Technical specifications: Detailed operating procedures for wastewater treatment
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General Provisions 1. These regulations are formulated to strengthen the management of sewage treatment equipment, processes, and water quality, ensure the safe and normal operation of sewage treatment, and achieve the objectives of purifying water quality, treating and disposing of sludge, and protecting the environment. 2. The operation, maintenance, and safety of wastewater treatment shall comply not only with these regulations but also with the provisions of **current relevant standards. 1 General Requirements 1.1 Operational Management Requirements 1. Operational managers must be familiar with the plant’s processing processes, as well as the operational requirements and technical specifications of the facilities and equipment. 2. Operators must understand the plant’s processing procedures, as well as the operating requirements and technical specifications of the facilities and equipment in their respective positions. 3. Each position should have process system network diagrams, safety operating procedures, etc., which should be displayed in a prominent location. 4. Operations managers and operators shall conduct inspections as required to check the operation status of structures, equipment, electrical systems, and instruments. 5. Operators of each position should keep operation records on time. The data must be accurate. 6. When the operator notices abnormal operation, they should handle it promptly or report it to the competent authority. 7. All mechanical equipment should be kept clean, with no leaks of water or air. 8. The weirs and pool walls of water treatment structures should be kept clean and in good condition. 9. Depending on the requirements of various mechanical and electrical equipment, regular inspections should be carried out to add or replace lubricating oil or grease. 1.2 Safety operation requirements: 1. Operators and maintenance personnel in various positions must undergo technical training and practical experience, and pass examinations before they can take up their duties. 2. The equipment should be started after all preparation work for startup has been completed. 3. The motor should not be started when the supply voltage is 5% higher or lower than the rated voltage. 4. When operating the electrical switches, the operator must follow the electrical work procedures. 5. The power must be turned off when maintaining various equipment, and a maintenance sign must be hung at the switch before work can begin. 6. On rainy or icy weather, operators should be careful to avoid slipping when inspecting or working on structures. 7. Clean the mechanical and electrical equipment as well as the surrounding area to maintain hygiene. It is strictly prohibited to wipe the moving parts of the equipment, and the washing water must not splash onto the cable terminals, the live parts of the motors, or the lubricated areas. 8. Operators in each position should wear complete personal protective equipment to ensure proper safety precautions. 9. Protection and life-saving facilities and equipment should be provided in prominent locations within the structure. 10. It is strictly prohibited for personnel not assigned to this position to operate the mechanical and electrical equipment of this position. 1.3 Maintenance Requirements 1. Operation managers and maintenance personnel should be familiar with the maintenance regulations for mechanical and electrical equipment. 2. The structure of the structures in question, as well as various gate valves, guardrails, ladders, pipelines, etc., should be regularly inspected, maintained, and treated to prevent corrosion; damaged lighting equipment should also be replaced promptly. 3. Various equipment connections should be regularly inspected and tightened, and the wear-prone parts of the couplings should be replaced periodically. 4. Various pipeline gate valves should be regularly tested for opening and closing. 5. The electrical control cabinet should be regularly inspected and cleaned, and its various technical performances should be tested. 6. The limit switches of the electric gate valve, as well as the interlock devices for manual and electric operation, should be checked regularly. 7. After each shutdown of the pump, the sealing condition of the packing or oil seal should be checked, and necessary actions should be taken. And add or replace the filler, lubricating oil, and grease as needed. 8. In any device equipped with steel wire ropes, the ropes must be replaced if their wear exceeds 10% of their original diameter, or if one of the strands in them has broken. 9. In addition to regular maintenance, various mechanical devices should also undergo major, medium, and minor repairs in accordance with the design requirements or those specified by the manufacturer. 10. When maintaining various mechanical devices, it is necessary to meet the technical requirements such as coaxiality and static balance, in accordance with the specifications of those devices. 11. Lubricating oil, grease, laboratory wastewater, and other debris removed from maintenance equipment must not be discharged into sewage treatment facilities. 12. When repairing mechanical equipment, temporary power cables must not be connected arbitrarily. 13. The testing, maintenance, and frequency of lightning protection and explosion prevention devices for buildings, structures, etc., shall comply with the regulations set by the electrical and fire safety authorities. 14. Protective equipment such as fire-fighting facilities should be regularly inspected and replaced. 2 Operating procedures for various systems: Operating procedures for the pH adjustment tank, reaction tank, and flocculation tank. 1. Start the raw water pump to feed wastewater into the pH adjustment tank; at the same time, open the air intake valve to keep the water in motion, with the air intake valve remaining open at all times. 2. Start the ferrous sulfate pump and the PAM pump, and adjust the dosage of ferrous sulfate and PAM by opening the reflux valve. 3. Regularly check the condition of the wastewater in the tank, inspect the floccules formed as a result of the reactions taking place, and adjust the amount of chemicals added; if the floccules are small, more PAM needs to be added. Operating Procedures for Pressurized Dissolved Air Flotation Process. The pressurized dissolved air flotation system is a method that combines the flocs formed in the reaction tank with tiny air bubbles, allowing them to rise to the surface due to buoyancy, thereby achieving the removal of substances such as CODcr, BOD5, and SS (suspended solids in water). 1. Start the return water pump to feed the return water into the container tank; the water level in the tank must be above half of the tank’s volume. Then, compressed air is added, and the air and water mix together in the dissolving tank for about 10 minutes. The resulting dissolved water is considered qualified when it becomes milky white in color, with the pressure maintained at around 0.3–0.4 MPa. 2. When the scum is at 50–100 mm, press the button to activate the scum scraper, which then scrapes the scum into the scum collection tank. 3. When the amount of slag in the slag collection tank reaches a certain level, raise the overflow gate of the air flotation tank to increase the water level and flush the slag collection tank; after flushing is complete, lower the gate back to the normal operating water level. Operating Procedures for the Aeration Biological Tank: The aeration biological system operates under aerobic conditions, where the organic substances in wastewater are oxidized and decomposed into simple inorganic substances through adsorption, oxidation, and reduction processes carried out by microorganisms present in the activated sludge, thereby achieving the purpose of wastewater purification. 1. Adjust the aeration volume according to specific conditions by controlling various valves to regulate the air intake volume. 2. The aeration tank should be process-controlled by adjusting parameters such as sludge load, sludge age, or sludge concentration. 3. The dissolved oxygen at the outlet of the aeration tank should be 2 mg/L. 4. The biological community of the activated sludge, the clarity of the supernatant, the color and condition of the sludge, as well as its odor should be monitored regularly, and relevant parameters reflecting the characteristics of the sludge should be tested and calculated at regular intervals. 5. Abnormal phenomena such as sludge bulking or sludge floating in the sedimentation tank, caused by changes in water temperature, water quality, or the operating mode of the aeration tank, should have their causes analyzed. Depending on the specific situation, the system’s operating conditions should be adjusted, and appropriate measures taken to restore normal operation. 6. When the water temperature in the aeration tank is low, appropriate measures such as extending the aeration time, increasing the sludge concentration, prolonging the sludge age, or other methods should be taken to ensure effective wastewater treatment. 7. When foam and scum form in the aeration tank, the cause should be analyzed based on the color of the foam, and appropriate measures should be taken to restore normal conditions. Turn on the defoaming pump as appropriate and sprinkle the defoamer. 8. Add nutrients to the biochemical tank according to the condition of the sludge; generally, the nutrients are added in a ratio of BOD5:N:P = 100:5:1. The N source is urea, and the P source is sodium phosphate or disodium hydrogen phosphate. Operating Procedures for Sedimentation Tanks 1. Regularly inspect the sedimentation efficiency of the sedimentation tank, such as the turbidity of the effluent, the height of the sludge layer, the condition of the suspended solids in the sediment, and any floating sludge or scum on the water surface. Check whether all pipeline fittings and sludge/scale removal devices are functioning properly, whether the flow from each weir is even, and whether there is severe blockage at the weirs. Remove any debris and floating objects that have accumulated in the effluent weirs and channels. 2. The sludge should be discharged in a timely manner based on its production volume and storage time; generally, the sludge is stored for 2–4 hours. The amount of return sludge is controlled using valves, while the excess sludge is sent to the sludge thickening tank; the ratio between return sludge and excess sludge is carefully regulated. The sludge discharge volume from the sedimentation tank can be determined based on the sludge settling ratio, the sludge concentration in the mixed liquid, and the sludge level height in the secondary sedimentation tank. 3. Monitor the water quality of the effluent from the sedimentation tank; sludge floating in the tank is not allowed. 4. The thickness of the supernatant in the sedimentation tank is generally around 0.5-0.7 meters. Operating procedures for the secondary reaction tank: When the water level in the outlet tank is equal to that in the secondary reaction tank, start the pump to feed water into the secondary air flotation tank for sludge and water separation. Stop the pump when the water level in the outlet tank drops to 10 cm above the bottom of the tank. The valve of the air pipe leading into the tank remains open, keeping the water in the tank in a stirred state. Operating procedures for filtration and backwashing: Filtration is primarily used to remove residual CODcr, BOD5, fine SS particles, as well as synthetic detergents from water after physical, chemical, and biological treatment. For filtration, cobblestones are used as the bottom support filler, quartz sand as the middle layer, and activated carbon as the upper filler. Since, after operating for a period of time, the filter media become saturated with contaminants and their adsorption capacity declines, which leads to a deterioration in the quality of the water output, backwashing is necessary to restore the activity of the filter media. 1. Close the inlet valve at the top of the filter tank and the outlet valve at the bottom, and open the backwash inlet valve. 2. Start the backwash pump and perform backwashing for 12 minutes. 3. Turn off the backwash pump, open the inlet valve at the top of the filter tank and the outlet valve at the bottom, and close the backwash outlet valve; the backwashing is then complete. Operating procedures for the sludge thickening tank: The sludge thickening tank is used to thicken the residual sludge from the sedimentation tank; the degree of thickening affects the efficiency of the dewatering machine. 1. Observe whether the flow from each outlet of the water discharge weir is even; ensure that the water discharge weir and the discharge channel remain unobstructed and clean. 2. Start the sludge dewatering pump and the filter press according to the actual conditions in order to remove water from the sludge. 3. The moisture content of the sludge discharged from the thickening tank should be controlled at 95-97%. Operation and management of sludge dewatering: 1. When using mechanical equipment for sludge dewatering, appropriate chemical regulators such as PAC or PAM should be employed. 2. The dosage of chemical regulators should be determined through experiments, taking into account factors such as the properties of the sludge and the solid concentration. 3. Once sludge dewatering is complete, the equipment and filter cloth should be washed immediately; otherwise, it will be very difficult to clean them once the accumulated sludge dries out. Blower operation management 1. The air volume of the blower should be adjusted according to the oxygen requirements of the aeration tank. 2. In the event of abnormal situations such as a sudden power outage in the fan and water/oil cooling systems, immediate action should be taken to ensure that the fan does not malfunction. 3. The ventilation duct of the blower should be kept clean, and no items are allowed to be present. 4. While the fan is in operation, the operator should pay attention to monitoring parameters such as the wind pressure, oil temperature, oil pressure, air volume, current, and voltage of the fan and motor, and record them promptly. If abnormal conditions cannot be ruled out, the machine should be stopped immediately. 5. It is necessary to regularly check whether the cooling and lubrication systems are unobstructed, and whether the temperature, pressure, and flow rates meet the required standards. Operation and management of cooling towers: The purpose of cooling towers is to reduce water temperature to a level suitable for microbial growth, thereby enhancing the ability of these microorganisms to degrade organic substances in wastewater. 1. Operate the cooling tower based on the water temperature in the neutralization tank; start the cooling pump when the water temperature in the tank is above 30°C, otherwise there is no need to start it. 2. When the fan and pump are operating simultaneously, the valve should be opened gradually to adjust the water flow to an appropriate level, in order to prevent excessive water flow that could cause water to spill out. Use the appropriate water level markers in the water receiver of the cooling tower to determine the proper water level. Preparation of drugs: 1. For FeSO4 and PAC, close the connection valve between the two tanks, pour the drugs into the drug tank, add water and stir simultaneously. Once the drugs are completely dissolved, open the connection valve to allow natural pressure to push the drugs into the other tank; close the connection valve again when starting the pump. The medicine pot needs to be cleaned from time to time to prevent blockages. 2. H2SO4, NaOH: Open the tap water valve, add water until the volume is half full, then turn on the pump to add H2SO4 or NaOH until the tank is full. Make sure to add water first, and then the medication. Appendix: Abnormal issues in sedimentation tanks and solutions (1) Fine suspended particles in the effluent indicate poor sedimentation performance in certain areas of the sedimentation tank; possible causes include shock from high water flow rates or prolonged overload ； The residence time was reduced due to short-circuiting, causing the flocs to flow out of the outlet weir before they could settle ； Excessive aeration in the aeration tank causes the sludge to oxidize and break down on its own. Solutions include adjusting the uneven distribution of water inlet and outlet facilities to reduce the impact of shock loads, which helps to overcome short-circuiting ； Adjust the operating parameters of the aeration tank to improve sludge flocculation performance; for example, supplement nutrients when they are lacking, shorten the sludge age if the sludge has aged too much, and adjust the aeration volume in cases of excessive aeration ； The impact of evenly distributing the load from the clarified water in the concentration tank, as well as the impact of the load from the excess sludge entering the primary sedimentation tank. (2) The outlet weir is dirty and the water flow is uneven. Sludge accumulation, algae growth on the weir, or debris stuck at the weir opening cause the weir to become dirty, and in some cases the openings are blocked, resulting in uneven water flow. The solution is to regularly remove the dirt that gets stuck at the outlet weir ； Appropriate chlorination is used for disinfection to prevent the growth and accumulation of sludge and algae at the weir. (3) Sludge floating. The reasons for sludge floating include: excessive sludge retention time, organic matter** ； In the sedimentation tank, the sludge undergoes denitrification, being reduced to N2 which causes the sludge to float to the surface. Solutions include: ensuring proper storage and sludge discharge times ； Check for faults in the sludge discharge equipment ； Remove sludge from the inner walls of the sedimentation tank, as well as from components or certain dead corners ； Reduce the nitration level of sludge in aerobic treatment systems ； Such as high-speed sludge return flow, adjust the sludge age ； Prevent sludge from entering and causing corrosion in other structures. (4) Sludge scraper failure: The sludge scraper stops operating due to reasons such as excessive load. Solutions include: reducing the sludge retention time and decreasing the amount of sludge stored ； Check whether the scraper is stuck by bricks, stones, tools, or loose parts ； Replace damaged components such as wire ropes and scrapper plates in a timely manner ； Prevent freezing on the surface of the sedimentation tank ； Reduce the speed of the sludge scraper. This post was last edited by hesonchang214 on 2009-4-25 13:26.]
Chapter 1 Overview 1.1 General Information on the Plant The wastewater treatment plant was designed in 1986 by the Oilfield Chemical Engineering Design Institute of the Ministry of Petroleum Industry, and it came online for operation in 1989. The original design’s sewage treatment capacity was designed to match a crude oil processing capacity of 150,000 tons per year. In 1998, due to the expansion of refining capacity, technical upgrades were carried out under the design of the East China Design Institute in order to match a crude oil processing capacity of 1.5 million tons per year. Two additional plug-flow aeration tanks, three secondary sedimentation tanks, two equalization tanks, and a neutralization tank were added, raising the designed wastewater treatment capacity to 250 m3/h; currently, the actual treatment volume is 80–100 m3/h. The entire station currently has 31 employees, including 3 management officers, 1 safety officer, 2 technical staff, and 3 operational staff. There are 4 production teams, with a total of 22 operators. 1.2 General Overview of the Facility The function of the wastewater treatment station is to collect production wastewater discharged by various production units in the plant, water from oil tanks in the tank area, as well as wastewater generated from cleaning the surfaces of the facilities. This wastewater is then treated to remove pollutants such as petroleum compounds, sulfides, volatile phenols, and COD, so that it meets the requirements of the GB8978-1996** Comprehensive Wastewater Discharge Standards, thereby ensuring the smooth operation of the entire plant. This facility uses a three-stage treatment process involving oil separation, flotation, and biological treatment. For oil separation, horizontal flow inclined plates are employed to remove larger petroleum-based pollutants in suspended form from the wastewater, taking advantage of the difference in specific gravity between oil and water. The flotation system operates using two stages of pressurized air flotation tanks connected in series, employing physicochemical methods. A high-efficiency jet pressurization system is used for dissolving air, and coagulants are added; as the bubbles emerge from the water, they rise to the surface as scum, thereby separating the pollutants from the wastewater. The biochemical treatment system employs two types of aeration: complete mixing aeration and plug flow aeration. It utilizes the activated sludge method in biological treatment, relying on the biological activities of microorganisms to degrade organic matter in water. When the water volume increases and the water quality deteriorates, it can be adjusted using regulating tanks or reservoirs. The sludge, scum, and remaining activated sludge collected by the device are temporarily stored in a sludge tank, and after centrifugal dewatering, they are processed collectively. Chapter 2 Production Principles and Process Flow Description 2.1 Production Principles Wastewater treatment makes use of physical, chemical, and biochemical principles to remove organic substances such as oils and suspended solids from wastewater, thereby purifying it. Wastewater treatment processes include pretreatment, oil separation, flotation, and biochemical treatment processes. Pre-treatment involves using grids to capture larger suspended solids or floating debris, thereby reducing the processing load on subsequent treatment facilities, preventing blockages in pumps, and ensuring their proper operation. Oil separation is the process of removing suspended petroleum pollutants from wastewater by utilizing the difference in specific gravity between oil and water. Through a period of rest and slow flow, the wastewater allows the oil particles to rise to the surface due to gravity, taking advantage of the difference in specific gravity between oil and water, thereby achieving separation of oil from water. Flotation is a process in which air is introduced into water containing polluted impurities; tiny bubbles are generated as carriers. As these bubbles rise from the water, they attach to the pollutants present in the water, causing them to rise to the surface as scum, thereby separating the pollutants from the wastewater. During the wastewater flotation process, coagulants are often added to improve the flotation efficiency, causing small oil particles and other fine particles to aggregate into oil-loving and water-repelling coagulum flocs. These coagulum flocs rise to the surface along with the bubbles, thereby enabling the removal of oil and suspended solids. For biochemical treatment, the conventional activated sludge method is used. Through the biological metabolism of microorganisms, organic matter in water is degraded, thereby removing pollutants. The operation modes of the activated sludge process I use consist of surface aeration (completely mixed aerated sedimentation tanks) and plug flow aeration. A completely mixed aeration tank uses surface impeller aeration, and it consists of four sections: the aeration zone, the distribution zone, the return zone, and the sedimentation zone. The tank is circular, with the inlet located at the center of the bottom and the outlet at the perimeter. Within the aeration zone, the wastewater mixes thoroughly and rapidly with the returned sludge; thereafter, this mixture flows into the sedimentation zone through the guiding area. The clear water is discharged through the outlet weir, while the settled sludge returns into the aeration tank via the return grooves surrounding the bottom of the aeration cylinders. The main structures for plug-flow aeration are the plug-flow aeration tank and the secondary sedimentation tank. The wastewater to be treated and the returned activated sludge enter the plug-flow aeration tank together to form a mixture. Air is introduced into the aeration tank via blowers through tubular aerators, allowing the wastewater to come into full contact with the activated sludge and providing the mixture with sufficient dissolved oxygen. Under these oxygen-rich conditions, the organic substances in the wastewater are metabolized by the microorganisms present in the activated sludge (nutrients are added according to the process requirements to stimulate bacterial activity; in our facility, phosphate fertilizers and urea are generally used). After that, the mixture flows into the secondary sedimentation tank. After precipitation, a portion of the activated sludge is continuously recycled back to the plug-flow aeration tank, while the water from the clarification zone of the secondary sedimentation tank is discharged via overflow into an external collection tank, from where it is pumped to the Jindi River for discharge. 2.2 Process Flow Description: (1) All oily wastewater in the plant passes through a grid and enters a lift tank, where it is lifted by lift pumps (Pump-1/4.5.6.) and then sent to a regulating tank ； The other stream has the floating oil removed in an oil separator, and then is pumped to the primary flotation tank by a primary flotation pump (Pump–2/1.2.3). From there, it is sent to the secondary flotation tank via a secondary flotation pump (Pump–4/1.2.3). After the suspended solids are removed, the liquid proceeds to a circular aeration tank and a plug-flow biological treatment tank for biochemical treatment. The mixture from the plug-flow biological treatment tank is settled in a secondary sedimentation tank before being discharged into the external transfer tank. The treated wastewater is then pumped out of the plant using an external transfer pump (Pump–8/1.2.3). The sludge at the bottom of the secondary sedimentation tank is returned to the activated sludge tank, where it is sent back to the plug-flow aeration tank via a pump (pump--12/1.2) for reuse. (2) The contaminated oil removed by the regulating tanks and oil separators is collected in the oil collection tank, and then transported to the oil storage tank by an oil transfer pump (Pump-3/1.2). (3) Sludge and slurry are transported by a sludge pump to the three-sludge tank, and then sent to the three-sludge dewatering unit via a slurry pump (Pump-13/1.2); alternatively, they can be fed into the sludge tank using a gear pump (Pump-17/1), where they are processed after dewatering. A certain amount of coagulant and flocculant must be added during the dewatering of sludge and slurry; at our facility, polyacrylamide and lime milk are commonly used. (4) Wastewater with high pH and high concentration is pumped by lift pumps (Pump-1/4.5.6) to the regulation tank for adjustment. Chapter 3 Main Process Operating Conditions and Control Parameters 3.1 Main Process Operating Conditions 3.1.1 Oil Separation Tank Items Amount of wastewater treated Oil content at outlet Parameter 100 m3/h ≯100 mg/l 3.1.2 Regulation Tank Items pH value Liquid level Height Parameter 6–9 ≯14.5 m 3.1.3 Flotation Tank Items Pressure in air dissolution tank Dosing concentration Length of floating scum Parameter 0.2–0.3 MPa 30–50 mg/l ≯2/3 of tank length 3.1.4 Biological Treatment Tank Items pH value Water temperature Settling ratio Sludge concentration Dissolved oxygen Sludge index Parameter 6–9 17–40°C 10–50% 2–5 g/l 2–4 mg/l 50–150 mg/l 3.2 Main Control Parameters 3.2.1 Properties of Raw Materials Serial Number Item Unit Parameter 1 Amount of wastewater m3/h 50–200 2 pH value mg/l 6–9 3 COD mg/l ≤800 4 Petroleum substances mg/l ≤500 5 Volatile phenols mg/l ≤30 6 Sulfides mg/l ≤10 7 Ammonia nitrogen mg/l ≤150 8 BOD5 mg/l ≤300 3.2.2 Process Control Parameters Serial Number Name Item Unit Parameter 1 Outlet of oil separation tank Petroleum substances mg/l ≤100 2 Total wastewater discharge outlet pH value mg/l 6–9 COD mg/l ≤120 Petroleum substances mg/l ≤10 Volatile phenols mg/l ≤0.5 Sulfides mg/l ≤1.0 BOD5 mg/l ≤30 Ammonia nitrogen mg/l ≤50 Suspended solids mg/l ≤150 3.3 Power and Raw Material Consumption 3.3.1 Power Consumption Serial Number Name Unit Consumption 1 Fresh water t/a 6000 2 Electricity kwh/a 2,000,000 3 Steam t/a 1000 4 Air m3/a 5000 3.3.2 Chemical Raw Material Consumption Serial Number Name Unit Consumption 1 Polyaluminum t/a 40 2 Hydrochloric acid t/a 500 3 Urea t/a 15 4 Phosphate fertilizer m3/a 10 Chapter 4 Operations of Key Positions 4.1 Oil Separation Position 4.1.1 Operation of the dirt removal machine (1) Clean any debris inside the tank before allowing wastewater to enter, and ensure that there are no blockages at the inlet and outlet of the pipes. (2) Is the lubricating oil within the allowable range? Are the fixing screws secure? Is the scraper able to move up and down smoothly and effectively? (3) During the water intake process, start the dirt remover once every 8 shifts to remove debris. (4) After the dirt remover finishes operating, the scraper stops at the lower position. 4.1.2 Operation of the regulating tank (1) Inspection and preparation ① All valves and manholes are airtight, leak-free, and operate smoothly. ② All indicator instruments are flexible and easy to use. ③ The breather valves must be complete and in good condition. (2) Operation ① Open the tank inlet valve. ② When the liquid level rises to 14 m, open the outlet valve. ③ Oil production begins when the oil layer thickness reaches 0.3 m; during oil production, the liquid level is maintained at 14.5–15 m. ④ Before starting oil reception, notify the relevant personnel and purge the pipeline with steam; only after it is cleared can the oil reception valve be opened to start receiving oil. ⑤ When the temperature display shows less than 35°C, steam heating is activated to raise the temperature to 50–70°C. ⑥ Water is not allowed to be present during oil collection; the stations involved before and after the collection process must maintain regular communication and keep proper records. ⑦ After stopping the oil intake, open the steam valve to purge the pipeline until steam is no longer observed. Once the pipeline has been purged, close the steam valve and the oil intake valve. ⑧ When the pH value reaches 9, stop feeding water and notify the relevant personnel. 4.1.3 Operation of the water-circulation vacuum pump (1) Preparation work ① Remove debris from the pump and its surrounding area. ②Check whether the foundation bolts of the pump are loose. ③Check whether the lubricant level is within the required range. ④Is the liquid level in the gas-water separation tank higher than that of the pump? ⑤Open the valve of the pump’s water supply pipeline. ⑥Open the pump outlet valve and close the inlet valve. ⑦Turn the shaft 2–3 weeks. (2) Start-up ① Press the start button; once the pump’s vacuum gauge indicates the desired level and remains stable, open the pump inlet valve. ②During operation, the motor temperature should not exceed 65°C, the bearing temperature should not exceed 70°C, the vibration at the bearings should not exceed 0.06 mm, and there should be no abnormal noises. ③The vacuum level and pressure should meet the process requirements. ④The filler leakage meets the requirements. (3) Stop the pump: ① Close the inlet valve. ②Press the pump stop button. ③Close the outlet valve after the pump stops running. ④Close the pump supply valve. ⑤Conduct inspections, maintenance, and repairs. (4) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②During routine inspections, its readiness as a backup should be checked according to the integrity standards. ③Maintain good hygiene and keep the backup pump clean and tidy. 4.1.4 Operation of lift pumps (This procedure applies to stuffing pumps such as transfer pumps and slurry pumps.) (1) Preparation ① Clean the inside and outside of the lift pump room thoroughly, and remove debris around the valves and within the lift tank. ②Check the pump lubricant level; it should be within the allowable range. ③Disc lift pump: 2–3 weeks. ④Fire-fighting equipment should be in good condition and complete. ⑤The production tools and records are complete and in order. (2) Startup ① When the liquid level in the lifting tank reaches 3 m, start the vacuum pump; once the desired vacuum level is achieved, press the start button. ②After the pump is rotating properly, slowly open the outlet valve. (3) Precautions during normal operation: ① Adjust the outlet valve of the lift pump to maintain a stable water level. ②Pay attention to the pressure gauge and ammeter readings to see if there are any fluctuations, and record them promptly. ③Whether there is emulsification in the lubricating oil. ④Pay attention to the temperature of the pump body and the motor. (4) Common causes of faults and their solutions
Fault | Cause | Solution
--- | --- | ---
No flow or low flow rate | (1) Air in the pump | (1) Release air again
| (2) Impeller rotating in reverse | (2) Correct the impeller rotation
| (3) Blockage at the inlet | (3) Remove the blockage
| (4) Low water level at the inlet | (4) Raise the water level
| (5) Leakage at the inlet packing gland | (5) Tighten the bolts at the inlet connection points; compress or replace the packing
Interrupted water output | (1) Too low water level at the inlet | (1) Add more water
| (2) Severe blockage or air leakage at the inlet | (2) Remove the blockage; tighten the bolts at the inlet connection points
| (3) Sudden stop of the pump | (3) Start a backup pump to maintain operations; contact an electrician for repair
| (4) The inlet valve core has fallen off | (4) Repair the valve
Excessive packing leakage | (1) The packing is damaged | (1) Replace the packing
| (2) Wear of the shaft sleeve | (2) Repair or replace the shaft sleeve
| (3) Insufficient packing or inadequate tightening | (3) Add more packing or tighten the gland nuts
| (4) Bent shaft | (4) Straighten it out
| (5) Misalignment of the water seal ring | (5) Adjust the water seal ring
| (6) Excessive misalignment between the coupling gears | (6) Realign them
Smoke coming from the gland packing or overheating of the gland | (1) The gland is tightened too much | (1) Adjust the gland nut bolts
| (2) The gland is tilted and rubbing against the shaft | (2) Adjust the gland
| (3) Blockage in the water seal tube | (3) Clean the pipeline
Sudden increase in pressure | (1) Sharp decrease in water flow rate | (1) Reduce the number of pumps in operation or increase the reflux valve setting
| (2) Blockage in the outlet pipeline | (2) Remove the blockage
| (3) The outlet valve core has fallen off | (3) Repair the valve
Vibration of the pump | (1) Unbalanced pump base | (1) Level the base
| (2) Bent shaft | (2) Straighten it or replace it
| (3) Loose foundation bolts | (3) Tighten them
| (4) Damaged rotating parts | (4) Replace or repair them
| (5) Air in the pump chamber | (5) Drain the air
| (6) Excessive misalignment between the coupling gears | (6) Realign them
Too low current | (1) Inlet valve open too little or the valve core has fallen off | (1) Adjust the inlet valve opening
| (2) Air in the system | (2) Release the air
| (3) Excessive wear or damage to the impeller | (3) Replace the impeller
| (4) Faulty ammeter | (4) Replace or calibrate the ammeter
Too high current | (1) Gland packing is tightened too much | (1) Adjust the gland nut bolts
| (2) Motor running on one phase | (2) Contact an electrician for repair
| (3) Motor capacity exceeds the specified value | (3) Replace the motor or reduce the diameter of the impeller
| (4) Faulty ammeter | (4) Replace or calibrate the ammeter
Abnormal noises from the motor | (1) High load on the motor | (1) Reduce the motor load
| (2) Motor running on one phase | (2) Contact an electrician for repair
| (5) Use a backup pump | (5) Use a backup pump; according to relevant regulations, the direction of the rotation mark on the backup pump should be red on odd-numbered days and white on even-numbered days. ②Keep the lubricant level at the 1/2–2/3 mark on the oil sight gauge; whenever the level drops, top it up with fresh oil immediately. ③During routine inspections, its readiness as a backup should be checked according to the integrity standards. ④Maintain good hygiene and keep the backup pump clean and tidy. 4.1.5 Operation of the cross-flow inclined plate oil separator. (1) Check the preparation work. ①Clean the inside of the pool and cover it with the lid. ②Ensure that the inlet valve, steam valve, sludge discharge valve, and vent valve of the oil separator are airtight and leak-free, as well as easy to operate. ③Check that the oil collection pipe is not blocked and is in a position where oil is not being collected. ④The inclined plate should be placed correctly. ⑤The oil and sludge skimmer should be in good standby condition. ⑥Fire-fighting equipment should be complete and in good condition. ⑦Production tools and records are complete and in order. (2) Operation procedures and precautions ① Open the water inlet valve to introduce water into the tank. ②Adjust the water distribution valves in each area to ensure even water distribution. ③The thickness of the oil layer on the pond surface reached 30 mm, so an oil and sludge skimmer was activated to collect the oil. ④When collecting oil, turn the handwheel of the oil collection pipe so that the cut end of the pipe faces downward. Once the lower edge of this cut end reaches the oil surface, start the oil and sludge skimmer to scoop the oil floating on the surface into the oil collection pipe for recovery. During operation, make sure the orientation angle of the oil collection pipe is appropriate, so as to prevent a large amount of water from being collected in it. ⑤After collecting the oil, be sure to keep the opening of the oil collection pipe pointing vertically upward, to prevent large amounts of water from overflowing into the pipe during heavy rain or high water levels, which could cause the oil collection tank to overflow. ⑥When the oil on the surface of the pool condenses and becomes less fluid, open the steam valve to melt the oil. ⑦The sediment in the pool is removed once a month; prior to removal, contact the relevant department to arrange for the collection of the sediment. ⑧If the oil content in the effluent is abnormal or blockage of the inclined plate is detected, gradual venting and flushing should be carried out. (3) Abnormal conditions and handling Abnormal conditions Causes Handling methods Excessively high oil content in the effluent (1) Emulsification caused by alkaline residues in the incoming water (2) Excessive oil content in the incoming water (3) Too thick oil layer with excessive sludge at the bottom of the tank (4) Excessive treatment volume (1) Send it to the regulation tank and contact the dispatch team for adjustment. (2) Collect oil and sludge in a timely manner. (3) Reduce the water inflow volume, or activate multiple tanks. Oil skimming and clumping: The temperature is too low and there is a high amount of heavy oil; turn on steam for heating. (4) Shutdown procedures: ① Close the water inlet valve. ②Cut off the power to the oil and sludge scraper. ③Open the sludge discharge valve to drain the water, and then clean and perform maintenance. 4.1.6 Operation of the oil and sludge skimmer (1) Inspection and preparation work ① Contact an electrician to check the power supply and ensure that the motor is safe and reliable. ②Check all bolts to ensure they are not loose. ③Check whether the chain is stuck and whether the scraper is in good condition. ④Check whether the lubricant level is within the required range. ⑤Clear the surrounding clutter. (2) Start: Press the start button. (3) Normal operation: ① Regularly check the motor temperature; it should remain within the allowable range. ②The gearbox should make no abnormal noises. ③Check whether the scraper is stuck and whether it moves up and down smoothly and reliably. ④The oil and sludge scraper should operate smoothly, without any jamming or deviation. ⑤The operating time is determined based on the thickness of the oil layer. ⑥In the event of a broken chain, machine jamming, or any other serious abnormality, the machine must be stopped immediately and the station notified. (4) Shutdown ① Press the stop button. ②The scrapers must all come to a stop on the water surface. 4.1.7 Operation of the regulation tank: (1) When the water quality parameters such as alkalinity and COD are too high, open the inlet valve of the regulation tank to collect the wastewater with high concentrations there for quality adjustment. ⑵ Based on the upstream water inflow volume and water quality, the discharge valve of the regulating tank is opened at the appropriate time to allow water to flow into the lift tank in a uniform manner and at a low flow rate. ⑶ The regulation tank should normally be kept empty, so that in the event of abnormal conditions (heavy rainfall, high-concentration wastewater), there is sufficient capacity available for regulation. 4.1.8 Operation of the sludge pump (Roths pump) (1) Preparation ① After the new pump is installed, before starting it up, fill the gearbox and reducer with L-AN46, an oil designed for full-loss systems. ②Check the sealing of all pipeline flanges and joints to ensure they are tight and leak-free. ③The pump should be filled with the fluid to be transported before starting. ④Before starting, the valves in the suction and discharge pipelines should be fully opened; it is strictly prohibited to start with the valves closed. ⑤Verify the motor direction; start the motor only after the direction is correct. ⑥Open the valve of the oil tank into which the waste oil is being poured. ⑦Before starting the pump, purge the pipeline; stop once gas is detected. (2) Operation ① After starting the pump, pay attention to the temperature of the bearings and the pump body. ②If abnormal noises from the pump and motor are detected (or if the ammeter needle rises rapidly), the machine should be stopped immediately for inspection. ③If a fault occurs in the piping system, the machine should be stopped immediately to resolve the issue. ④Check the liquid level in the oil collection tank and the amount of oil collected from time to time. (3) Shutdown ① After turning off the motor, close the inlet and outlet valves of the pump. ②Before shutting down the machine, never close the outlet valve first, as this can easily damage the pump. ③After stopping the pump, purge the pipeline with steam. ④Faults and troubleshooting methods. (4) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②Keep the lubricant level at the 1/2–2/3 mark on the oil sight gauge; whenever the level drops, top it up with fresh oil immediately. ③During routine inspections, its readiness as a backup should be checked according to the integrity standards. ④Maintain good hygiene and keep the backup pump clean and tidy. 4.1.9 Operation of the oil tank (1) Inspection and preparation ① The access holes for the steam and water valves of the oil tank should be airtight and leak-free, as well as easy to operate. ②The indicator gauge is flexible and easy to use, with accurate readings. ③All debris inside and outside the tank area has been removed. ④Fire-fighting equipment and breathing valves must be complete and in good condition. (2) Oil inlet operation for the oil sludge tank: ① Open the oil inlet pipeline and the steam valve, and perform steam purging; close them once steam is observed at the outlet. ②Check the oil level in the tank. ③Start the sludge pump to transfer oil into the tank, making sure that the oil level in the tank does not exceed the safe level. ④After stopping the oil supply, turn on the steam to purge the pipeline until steam is observed. Once the purging is complete, close all relevant valves and take measurements while keeping a record of them. (3) Heating and dehydration ① Turn on the steam trap, then start steam heating, maintaining the temperature at 70–85°C. ②During the heating process, the steam flow rate should not be too high; regular inspections must be carried out to prevent contaminated oil from spilling over the tank. ③After heating is complete and 8 hours of settling have passed, the dehydration valve is opened to start the dehydration process. During this process, the personnel on duty must check regularly and close the dehydration valve immediately upon detecting any oil. ④During dehydration, the valve should not be opened too wide to prevent excessive oil from entering. ⑤Once the tank is full, and if the water content in the contaminated oil is less than 5%, contact the dispatch team to transfer the oil to another tank or facility, and keep proper records. (4) Oil delivery ① Conduct measurements and take records before oil delivery. ②Contact the oil receiving unit to clean the lines and switch the valves. ③Open the outlet valve of the oil tank and start the oil transfer pump to deliver oil. ④After the oil delivery is complete, stop the pump, close the outlet valve of the oil tank, and record the measurements taken after the delivery. ⑤Complete the task, report to production scheduling and the station, and switch the valve. (5) Calculation of the oil delivery volume: Formula: W = D × (V_before – V_after) × (1 – R) Where: W is the net weight of the oily waste delivered (in tons); R is the water content of the oily waste; V_before is the volume of the oily waste in the tank before delivery (in cubic meters); V_after is the volume of the oily waste in the tank after delivery (in cubic meters); D is the density of the oily waste (in tons per cubic meter). (6) Precautions: ① Regular inspections should be carried out during the dehydration process of the oily waste. ②After the contaminated oil is dehydrated, if the test results are unsatisfactory, repeat the dehydration process. ③The oil inlet height and heating temperature must not exceed the specified values. ④Strangers are strictly prohibited from entering the oil tank area, and a fire permit is required for any welding work. ⑤Take measures to prevent freezing and condensation in winter. ⑥Maintain good environmental hygiene. (7) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②Keep the lubricant level at the 1/2–2/3 mark on the oil sight gauge; whenever the level drops, top it up with fresh oil immediately. ③During routine inspections, its readiness as a backup should be checked according to the integrity standards. ④Maintain good hygiene and keep the backup pump clean and tidy. 4.1.10 Sludge Recovery Operations (1) Sludge Recovery Management ①Sludge recovery is carried out in accordance with the regulations set by the head office, under the unified coordination of the control room. ②The contaminated oil is transferred as arranged by the head office’s dispatch or planning department; after being signed off by the supervisors of that department, notification is sent to the wastewater treatment station, which then receives it in accordance with the specified quantity and quality standards. ③Once the storage tank is filled, the sewage treatment station is responsible for heating it. The control room coordinates with Station 1 for oil handling and the sewage treatment station to carry out the oil transfer process; the sewage treatment station starts the pumps to transfer the oil, which is then received by Station 1. After the transfer is complete, the pumps are stopped and the tank is purged with steam, ready for future use. (2) Sludge oil recovery operation: Process flow for sludge oil recovery: Equipment: Submersible pump, model 40LY250, flow rate: 10 m3/h, head: 90 m, power: 11 Kw; Sludge oil tank, dimensions φ1400*3500, capacity: 5 m3. Figure 1: Flow diagram for sludge oil recovery. (3) Operation of the submersible pump: (1) Preparation work: ① Check the tightness of all pipeline flanges and connections; they must be leak-free. ②Check that all oil and steam valves are airtight, leak-free, and operate smoothly. ③Check that all indicator instruments are flexible to use and provide accurate readings. ④Clean all debris inside and outside the oil tank. (2) Oil tank filling operation: ① Upon receiving the notification, check the liquid level in the tank, open the manhole access, and transfer the dirty oil from the unloading vehicle into the dirty oil tank. ②Regularly check the liquid level in the oil sludge tank, making sure that the level inside the tank does not exceed the safe height. ③After stopping the oil inflow, close the oil inlet manhole properly. (3) Oil tank heating operation ① Open the line from the steam outlet condensate to the sewage well. ②Turn on the steam line for heating, and control the oil temperature at 70–85°C. ③Check the temperature and liquid level inside the tank to prevent overflow caused by excessive temperature. (4) Oil transfer operations ① Conduct gauge checks and make records before receiving oil. ②Contact the oil receiving unit to purge the pipeline; once steam is detected at the outlet, switch the oil transfer valve. ③ Open the outlet valve of the sludge pump and start it to transfer the sludge. ④After the transfer of oil is complete, stop the pump, close the outlet valve of the oil tank, and prepare the measurement records after the oil delivery. ⑤Notify the production scheduler and the oil station to contact the team responsible for purging the oil pipelines, and stop the steam supply once steam is detected at the outlet. 4.2 Flotation Posts 4.2.1 Operation of flotation pumps, (this procedure applies to flotation pumps, air flotation circulation pumps, and other mechanical-sealed pumps.) ） (1) Preparation ① Contact an electrician to check the power supply and ensure that the motor is safe and reliable. Press the motor’s start button briefly to test whether its rotation direction is correct; rotation from the top of the motor toward the pump should be in a clockwise direction. The testing time should be short to prevent dry wear of the mechanical seal. ②Check whether the bolts connected to the outside of the pump are complete and firmly tightened. ③Check the water levels in the primary and secondary flotation sumps to ensure they are within the specified range. ④Open the inlet valve fully. ⑤Close the outlet valve. ⑥Open the exhaust valve to fill the entire pump with liquid, and close it once it is full. ⑦Spin the pump (2–3 weeks) to allow the lubricant to reach the mechanical seal faces. (2) Start-up ①Start the motor and check whether the pump rotates in the correct direction. ②By adjusting the opening degree of the outlet valve, the pressure (02–0.4 Mpa) and current (20.5–35.5 A) remain within the specified range. (3) Operation: ① After the pump is started, carry out operation and maintenance strictly in accordance with the \"five-step method\" for pumps (listen, touch, check, observe, compare). ②Check for shaft seal leakage; under normal conditions, the mechanical seal should leak less than 3 drops per minute. ③Check the motor; the bearing temperature rise should be ≤70°C. ④Check whether the pressure, flow rate, and current are within the specified range. (4) In the event of the following situations that cannot be resolved, switch immediately and report. ①The current is extremely high. ②Severe vibration and abnormal noises from the pump. ③The electrical system is smoking or on fire. ④A serious abnormality has occurred. (5) Stop the pump: ① Close the outlet valve. ②Press the stop button. (6) Common causes of faults and troubleshooting methods. Fault symptoms, possible causes, and troubleshooting methods: The water pump does not deliver water. (1) The inlet valve is not open, the inlet and outlet pipes are blocked, or the impeller in the flow channel is blocked. (1) Check and remove obstructions. (2) The motor is running in the wrong direction; it has a low speed due to a missing phase. (2) Adjust the motor direction and tighten the motor connections. (3) Air leakage in the suction pipe. (3) Tighten all sealing surfaces to remove air. (4) The pump is not filled with liquid; there is air inside the pump chamber. (4) Open the pump cover or the exhaust valve to release air. (5) Insufficient imported water supply, excessive head pressure, and valve leakage. (5) Stop the machine for inspection and adjustment. (6) Excessive pipeline resistance, improper pump selection. (6) Reduce pipe bends and select a new pump. Insufficient water pump flow (7): Blockage in the pipes, pump flow channels, and impeller area, scale deposition, and insufficient valve opening. (7) Remove the blockage and readjust the valve opening. (8) Low voltage (8) Voltage stabilization (9) Impeller wear (9) Replace the impeller. Excessive power (1) Operating beyond the rated flow rate (1) Adjust the flow by closing the outlet valve. Too high suction lift (2) Reduce it. (3) Pump bearing wear (3) Replace the bearings. Fault symptoms, possible causes, and solutions: Noise and vibration (1) Unstable pipeline support (1) Stabilize the pipeline. (2) Gas mixed in the liquid (2) Increase the suction pressure to expel gas. (3) Cavitation occurring (3) Reduce the vacuum level. (4) Damaged bearings (4) Replace the bearings. (5) Motor operating under overload and overheating conditions (5) Make adjustments. Motor overheating (1) Excessive flow rate, resulting in overload operation (1) Close the outlet valve. (2) Rubbing/scratching (2) Check and eliminate the cause. (3) Damaged motor bearings (3) Replace the bearings. (4) Insufficient voltage (4) Stabilize the voltage. Pump leakage (1) Wear of the mechanical seal (1) Replace it. (2) Holes or cracks in the pump body (2) Weld or replace the pump body. (3) Uneven sealing surface (3) Repair it. (4) Loose installation bolts (4) Tighten them. 4.2.2 Operation of flotation dosing pumps (metering pumps) (1) Preparations before starting the pump: ① Check whether the bolts at all connection points are tight. ②An appropriate amount of engine oil is injected into the transmission case depending on the ambient temperature and the temperature under conveying conditions. ③Rotate the pump (for 2–3 weeks), moving the plunger back and forth several times to ensure there is no sticking, then align the pump’s stroke zero position with the zero mark on the adjustment gauge. ④Check the motor wiring to ensure the pump rotates in the specified direction. ⑤Prepare the solution in the tank (aluminum hydroxide chloride). ⑥Start the motor, and the pump begins to operate. (2) Precautions during operation: ① If abnormal noises are heard while the pump is running, it should be stopped to determine the cause, and the station should be informed. ②When the leakage rate exceeds 15 drops per minute, the packing gland should be tightened appropriately. ③When the temperature at the plunger packing rises rapidly, the pump should be stopped, the packing gland should be loosened, the cause should be investigated, and the pump can be put back into operation only after the issue is resolved. ④The temperature of all areas must not exceed 65°C. (3) Parking ① Cut off the power supply to stop the motor from operating. ②Close the valve on the inlet pipeline, but be sure to open it before starting the pump. (3) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②Keep the lubricant level at the 1/2–2/3 mark on the oil sight gauge; whenever the level drops, top it up with fresh oil immediately. ③During routine inspections, its readiness as a backup should be checked according to the integrity standards. ④Maintain good hygiene and keep the backup pump clean and tidy. 4.2.3 Operation of the flotation cell (1) Inspection and preparation work ① Remove debris from the chemical dosing tank, dissolver tank, flotation cell, and around the valves. ②Check whether the valves associated with the position are airtight, leak-free, and functional. ③Check whether the instruments for various indicators are sensitive and accurate. ④The slag scraper, automatic control equipment, and suction valve are in good condition and ready for use. ⑤Prepare an aluminum hydroxide solution with a concentration of 50 mg/l in the dosing tank. ⑥Water is introduced into the flotation tank to the specified level. ⑦Prepare the production record report. (2) Operation ① Inlet valve and outlet valve of the air flotation tank. ②Open the inlet and outlet valves of the air flotation circulation pump. ③Start the dosing pump to inject the chemical solution into the pipeline before the air flotation pump. ④Adjust the releaser to produce uniform and fine bubbles. (3) Precautions during operation. ①Adjust the dosage of chemicals flexibly according to water quality changes; the typical addition concentration is 30–50 mg/l. ②Regularly check the chemical dosing pipeline to ensure it remains unobstructed. ③Maintain the pressure in the air flotation tank at 0.2–0.3 Mpa. ④Maintain regular communication with the oil separation team to ensure a steady and even water flow. ⑤When the scum on the surface of the tank reaches 2/3 of the tank length, start the scum scraper to remove it. When discharging the scum, the water level should be kept slightly above the overflow weir; care should be taken to minimize the amount of water involved and to avoid vigorous stirring, so as to prevent the scum from being carried away by the water flow and entering the biological treatment system. ⑥The sludge at the bottom of the tank is cleaned periodically, depending on the effluent from the air flotation tank and its operating time. (4) Shutdown procedure: ① Stop the chemical dosing pump and close the chemical feed valve. ②Stop the air lift pump and circulation pump, and open the vent valve of the dissolved air tank. ③Collect the remaining scum. (5) General methods for troubleshooting. Sequence Number, Fault, Cause, Solution: 1. Bubbles are large and uneven – (1) The air flotation circulation pump does not start; (2) The air flotation circulation pump keeps running. Contact the maintenance team for the automation system. 2. Excess oil content in the effluent – (1) High oil content in the effluent from the oil separator; (2) Insufficient dosage of chemicals or blocked pipelines; (3) Excessive accumulation of scum; (4) The air flotation process is not operating or keeps running. (1) Contact the team to improve control measures; (2) Repair the chemical dosing system or increase the dosage; (3) Remove scum promptly; (4) Carry out repairs promptly. 4.2.4 Operation of the flotation dissolved air tank: 1) Operational adjustments – ① Maintain pressure at 0.2–0.3 MPa; the optimal pressure for achieving good flocculation results is 0.25 MPa. ②If the pressure is not within the controlled range, adjust the relief valve or the outlet valve of the flotation pump to bring the pressure back within the controlled range. 2) Precautions (Operation of the 1# Dissolution Tank for Secondary Flotation) ① When the flocculation effect is poor, it is not possible to adjust the flocculation by using the manual mode in the electrical control cabinet; instead, the pressure must be adjusted according to the method specified by the ultrasonic water level automatic control system, so as to keep it within the desired range. ②Only if the ultrasonic water level automatic control system fails or other faults occur should the manual mode be used to ensure the effectiveness of flocculation. 4.2.5 Operation of the slag scraper (1) Preparation ① Contact an electrician to check the electrical components. ②Check the bolts in all areas; there should be no looseness. ③Check that the oil quality and quantity meet the requirements. (2) Start: Press the start button to activate the slag scraper. (3) Operation ① Check whether the slag scraper moves at a steady speed. ②The sound of the gearbox should be normal. ③Check whether the scraper is stuck and if the water depth is appropriate. (4) Stop immediately in the following situations. ①After pressing the start button, the slag scraper does not operate. ②The machine got stuck and other serious abnormalities occurred. (5) Stop: After all the scrapers of the slag scraper have been raised above the water surface, press the stop button. 4.2.6 Operation of the scum pump (1) Preparation ① Contact an electrician to check whether the power supply and motor are safe and reliable, and verify the motor’s rotation direction. ②Check the bolts connecting the pumps and pipelines; they must be complete, tight, and secure. ③Check the sealing of all pipeline flanges and joints, regularly inspect whether the filters are unobstructed, and remove debris around the pump. ④Check whether the dewatering valve of the slag tank is closed and whether the inlet valve on the slag tank is open. ⑤Inject liquid into the forward pump before starting (for the first start-up or after purging). ⑥Open the inlet valve and the outlet valve. ⑦Turn the pump 2-3 times. (2) Start up: ① Start the motor and check whether the pump rotates in the correct direction. ②Operate and maintain the pump strictly in accordance with the \"five-step method\" for pumps (listen, feel, check, observe, compare). (3) Stop the pump: ① Cut off the power supply to stop the motor from running; ② Close the inlet valve, but be sure to open it before restarting the pump. (4) Precautions: ① After the pump is started, it should operate smoothly without any abnormal noises; otherwise, it should be stopped to determine the cause, and the station should be informed. ②Check the temperature of all areas; it must not exceed 65°C. ③Operation without a load is strictly prohibited; if the output is low, the cause should be checked. ④The inlet valve and outlet valve must not be closed during the start-up, shutdown, or operation of the pump. ⑤After removing the slag in winter, purge with steam to prevent pipeline freezing and cracking. 4.3 Biochemical Treatment Unit 4.3.1 Operation of the circular aeration tank (1) Preparation ① Remove any debris inside and outside the biochemical treatment unit, and close the sludge discharge valve. ②Check that the aerator and electrical control units are in good standby condition. ③Cultivate active sludge properly and control various influent parameters. ④Prepare disodium hydrogen phosphate and urea. ⑤Prepare the sampling device for testing. ⑥Prepare the production tools and operation records. (2) Shipment operation ① Slowly open the water inlet valve to introduce water into the tank. ②Start the aerator. ⑶ Precautions: ① Closely monitor water quality and sludge properties (analyze the sedimentation ratio every two hours, and analyze dissolved oxygen every four hours). If any abnormalities are detected, report them to the station promptly, identify the cause, and adjust the operations accordingly. ②Pay attention to adjusting the inlet valve; sludge backflow is strictly prohibited. In case of sludge backflow and loss, report immediately, reduce the processing volume, and gradually resume normal operation once the sludge flow returns to normal. ③The sludge discharge time and amount are determined based on the settling ratio and the sludge concentration (controlled at 3–5 g/l). During sludge discharge, close the water inlet valve and shut down the aerator and blower for 30 minutes; then open the sludge discharge valve to release the sludge, paying attention to the level of water as this process takes place. When the water level drops to the expected level, close the sludge discharge valve, keeping the sludge settling ratio at around 25%. ④Based on the conditions observed during operation, purge the return gap to prevent sludge blockage (stop water inflow during purging, open the air valve for the return gap, and purge for 5–15 minutes; after purging is complete, close the air inlet valve. Once the sludge in the clarification zone has settled, open the water inlet valve to resume normal operations). ). ⑤Based on the analytical tests, phosphates (or other artificial nutrients) are added per shift in accordance with the process requirements. ⑷ Shutting down procedure: ① Slowly close the water inlet valve. ②Tingyun aeration machine. ③When the biochemical tank is out of use for more than a week, nutrients should be added to it as required to sustain the sludge. If it is necessary to clean the aeration tank, the activated sludge can be transferred to another tank; after cleaning, it can be returned to the original tank. (In cases of long-term disuse, the sludge should be stored by allowing it to settle naturally in order to preserve the microorganisms.) (5) Causes of common faults and their solutions. Sequence Number, Fault, Cause, Solution: 1. Sludge floating: (1) Deterioration of water quality; (2) Sudden rise in water temperature; (3) Blockage of the return gap; (4) Excessive inflow of water. Solutions: (1) Take measures to improve water quality; (2) Add fresh water; (3) Clean the return gap; (4) Adjust the water flow rate. 2. Sludge deposition: (1) Low return flow rate; (2) Low rotation speed of the aerator. Solutions: (1) Adjust the return gap; (2) Increase the rotation speed of the aerator. 3. Decrease in sludge volume: (1) Poor water quality; (2) Insufficient oxygen supply; (3) Insufficient nutrients. Solutions: (1) Improve water quality; (2) Increase the rotation speed of the aerator; (3) Add more nutrients to support sludge growth and supply fresh sludge. 4.3.2 Operation of the aerator: (1) Preparations before startup: ① Contact an electrician to check the power supply, ensure that the control system is reliable and the direction of operation is correct, then supply power. ②Keep the lubricating oil at the gauge scale line. ③Turn the shaft 2–3 weeks to check for any sticking. ④Open the inlet valve to introduce wastewater into the tank, ensuring that the impeller of the aerator is at the desired submersion depth (usually 40 mm); open the return window to 1/3–1/2 of its capacity. (2) Start-up ① Adjust the governor knob so that the pointer points to the “0” position. ②Press the start button to activate the aerator. ③Adjust the aerator speed based on the dissolved oxygen in the effluent and the BOD5 content in the influent. (3) Operation: ① After starting up, carry out maintenance tasks strictly in accordance with the \"five-step method\" of listening, touching, checking, observing, and comparing. ②The oil temperature of the gearbox is <65°C, and the bearing temperature is <70°C. ③Check for noise and vibration. (4) Parking: Press the parking button. (5) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②During routine inspections, its readiness as a backup should be checked according to the integrity standards. ③Maintain good hygiene and keep the backup pump clean and tidy. 4.3.3 Operation of the push-flow biochemical system (1) Preparation work. ①Remove debris inside and outside the tank, and close the drain valve as well as all bypass valves. ②Check whether the blower and sludge return pump are in good standby condition. ③Check whether the sludge discharge valve of the secondary sedimentation tank and the valves of each unit in the plug-flow aeration tank are flexible and functional. ④Check the air supply pipeline for push-flow aeration for any air leaks. ⑤Prepare the sampling device for testing. ⑥Prepare the production tools and operation records. (2) Shipment operation ① Slowly open the water inlet valve to introduce water into the tank. ②Start the blower. ③Adjust to ensure even air supply to each unit. ④After the water exits the secondary sedimentation tank, adjust the sludge discharge valves of the tank to ensure uniform sludge discharge from each tank. ⑤Regularly adjust the return flow rate of sludge. (3) Shutdown procedure ① Slowly close the water inlet valve. ②Shut down the blower. 4.3.4 Operation of the blower (1) Preparation for startup ① Check whether the pipes, silencers, and filter devices are in proper condition, whether there are any residual substances in the pipes, and whether all bolt connections are tight and secure. ②Check whether the bearing housing is filled with grease. ③Check whether the indicator is at the “0” position. ④Check the power supply to ensure that the wiring is safe and correct, that the voltage is normal, and that all switches and buttons are flexible, reliable, and functioning properly. ⑤Run the pump for 2–3 weeks, and check for any blockages or abnormal noises. ⑥There is a blower with cooling water; open the cooling water valve. ⑦Press the jog button to test operation and check the fan direction. (2) Startup ① Close the inlet and outlet valves (i.e., start the machine under no-load conditions; the outlet valve does not need to be closed). ②Start the motor. ③After starting up, pay attention to the vibration and noise; if anything abnormal is detected, stop the machine immediately for inspection and report the situation for prompt handling. ④Once the motor reaches its rated speed and there are no abnormalities in any of its components, open the inlet and outlet valves as soon as possible. At the same time, pay attention to the ammeter reading, ensuring that it remains below the motor’s rated current value. (3) Inspection after startup ①Check for any abnormalities in internal sound and vibration. ②Check whether there are any abnormalities in the motor load. ③Check for any gas leaks at all connections. ④There is a blower for cooling water; check that the cooling water flow is unobstructed to prevent any interruptions. (4) Inspection during operation ① Record wind pressure, air volume, bearing temperature, etc. at regular intervals. ②During operation, pay constant attention to the sound and vibration levels; if surge noises or excessive vibration are detected, stop the machine immediately for inspection and report to the workshop. ③When the radial amplitude at the bearing area exceeds 0.06 mm, the machine should be stopped for maintenance. ⑸Pressure and air volume adjustment: ① If the pressure is high and the air volume is low, slowly open the outlet valve until the required conditions are met ； ②If the pressure is high and the air volume is large, the inlet valve should be closed partially ； ③If the pressure is low but the air volume is high, the outlet valve should be closed gradually until the desired level is reached ； ④If the pressure is low and the air volume is small, the inlet valve should be opened wider until satisfactory results are achieved. ⑹Parking ① When parking, first press the stop button, then quickly close the inlet and outlet valves. ②During the shutdown process, pay attention to whether there are any abnormal noises inside the machine and whether the shutdown time is unusually short. ③For blowers with cooling water, close the cooling water valve. ④ During long periods of shutdown, rotate the fan rotor 180 degrees at intervals. ⑺Causes of Faults and Troubleshooting Methods Fault Condition Cause Solution Excessively high bearing temperature Excessive oil injection Drainage Bearing overheating and damage (1) Insufficient oil amount (2) Poor quality of oil (1) Add water (2) Change the oil ⑻ Spare pump ① Rotate the spare pump in accordance with relevant regulations; the rotation mark should be such that it faces upward: red on odd-numbered days, and white on even-numbered days. ②During routine inspections, its readiness as a backup should be checked according to the integrity standards. ③Maintain good hygiene and keep the backup fans clean and tidy. 4.4 Transfer Pump Operation 4.4.1 Operation of the transfer pump (see Section 1.4, Operation of the Lift Pump) 4.4.2 Operation of the sludge return pump (1) Preparation work ① Use a megohmmeter to check that the insulation resistance between the motor stator windings and ground is not less than 1 megohm. ②Check that the cable is free of damage or breaks, and that it is properly grounded. ③Starting is not allowed when the voltage exceeds 10% of the rated value. (2) Start-up ①Open the outlet valve. ②Turn on the power and jog the motor. ③Pay attention to checking the operation of the pump, such as whether there are any noises, and check the current and voltage conditions of the motor while the pump is running. (3) Parking ①Close the valve. ②Turn off the power supply to stop the motor. 4.4.3 Three-Phase Sludge Dewatering System 4.4.3.1 Operation of Horizontal Screw Discharge Sedimentation Centrifuge (1) Preparation ① The exposed fabric parts of the centrifuge and all bolts should be tightened. ②Check the flexibility of the drum; turn it 2–3 times. It should rotate smoothly, without any abnormal noises caused by jamming or sticking, and it should rebound when at rest. ③Click to check whether the motor rotates in the correct direction. (2) Start-up ① Set the frequency of the inverter to the specified value. ②Press the start button. ③Once the motor current or frequency reaches the set value, slowly open the feed valve. ④It is advisable to regularly adjust the feed valve to keep the quality of the effluent water from becoming too dark. ⑤Start the chemical dosing pump simultaneously with feeding. (3) Shutdown ①Stop the dosing pump. ②Close the feed valve. ③Open the clean water valve and flush for 10 minutes. ④Shut off the clean water valve and stop the machine after 5 minutes. (4) Precautions: It is not allowed to flush the centrifuge with clean water after it has been shut down. (5) Common faults of centrifuges and troubleshooting methods
Serial Number | Fault Symptoms | Possible Causes | Solutions
1 | Excessive overheating of the main bearing | 1. Too much grease applied to the bearing 2. Tight fit between bearings 3. Damaged bearing (inflexible rotation) | 1. Stop applying grease and run the machine at low speed for a while 2. Repair or grind the bearing housing to achieve a J7/h6 fit 3. Replace the bearing
2 | Severe vibration when the machine is not in operation | 1. Blockage in the drum and screw conveyor 2. Loose connection flanges of the differential 3. Misalignment of the drum’s scale lines during maintenance, resulting in loss of dynamic balance 4. Severely worn screw blades 5. Loose bolts connecting the main unit and motor | 1. Remove deposits 2. Check the concentricity of the differential and replace damaged parts 3. Realign the scale lines 4. Repair the screw blades 5. Tighten the bolts
3 | Severe vibration during feeding | 1. Uneven feeding or impact forces 2. Belt slippage, causing blockage in the drum | 1. Ensure even feeding 2. Remove deposits and readjust the belt
4 | Sediments cannot be discharged; the clear liquid flows normally | 1. Reverse rotation direction 2. Too loose belt, causing blockage in the drum 3. Blockage in the feed pipe (or accumulation of material inside the drum) | 1. Rotate in the correct direction 2. Adjust the belt and remove deposits 3. Clear the pipes of deposits
5 | Neither the solid nor liquid phases are discharged | 1. Blockages in the valves and feed pipes 2. Blockage at the outlet of the feed hopper | 1. Remove deposits from the pipes or replace the valves 2. Remove deposits from the feed hopper
4.4.3.2 Operation of the chemical dosing tank
(1) Preparation work ① Remove any debris from the surrounding area. ②Check for leaks in pipelines, valves, etc. (2) Operation: ① Open the valves before and after the sand remover. ②Open the valve for feeding into the tank. ③Start the submersible sewage pump. ④Open the outlet valve of the submersible pump. ⑤Start the chemical dosing pump simultaneously with the submersible sewage pump to add chemicals to the dosing tank. ⑥After filling the tank, open the air valve and stir for 5–10 minutes. ⑦Feed the degassing fan 30 minutes after the wind has stopped. (3) Shutdown ① Close the pump outlet valve. ②Stop the pump. ③Stop adding chemicals, and close the valves of the sand remover and the chemical feed tank. 4.4.3.3 Operation of the dosing machine (1) Preparation work ① Check that all bolts are securely tightened. ②Check whether the lubricant level in the gearbox meets the requirements. ③Rotate the shaft for 2–3 weeks and check whether there is any jamming in the gearbox. (2) Start-up ① Press the start button to activate the mixer. ②Observe the startup of the mixer slurry. (3) Operation ① Check whether the lubricating oil is normal. ②Check the gearbox and other components for oil leaks. ③Check for abnormal temperatures, noises, or vibrations; if any abnormalities are detected, stop the machine immediately to address the issue or report it. (4) Causes and solutions for common faults. Serial number, Fault, Cause, Solution: 1. Mixer does not move: 1. Power outage; 2. Problem with the reducer. 1. Contact an electrician to handle it; 2. Perform maintenance. 2. Excessively high temperature: 1. Insufficient lubricant level; 2. Damaged lubricant; 3. Incorrect lubricant grade; 4. Damaged gearbox components. 1. Add lubricant to the required level; 2. Replace the lubricant with the correct grade; 3. Change the lubricant; 4. Perform maintenance. 3. Abnormal noises: 1. Motor failure; 2. Damaged reducer bearings. 1. Perform maintenance; 2. Perform maintenance. Chapter 5: Methods for adjusting operations in key positions. 5.1 Oil separation position. 5.1.1 Regularly operate the grid cleaner to remove debris from the incoming water. 5.1.2 Adjust with acid based on the pH of the incoming water to prevent stress on subsequent treatment units. 5.1.3 Based on the water quality and quantity of the water supplied by the head plant, recycled water, regulating tanks, and adjustment ponds are used for regulation to ensure stable operation of the oil separator. 5.1.4 Regularly remove surface oil from the oil separator and regulating tank. 5.1.4 Ensure proper dehydration of the oily sludge tanks; once the water content of the oily sludge meets the required standards, it should be promptly transferred to the relevant units for treatment. 5.2 Flotation Unit 5.2.1 Treat the sewage after oil separation based on the conditions of the incoming water, to ensure stable operation. 5.2.2 Add flotation reagents as appropriate, and use air flotation to remove emulsified oil from wastewater. 5.2.3 Adjust the flotation tank release valve, or control the outlet pressure of the air flotation pump, to maintain the pressure in the dissolved air tank at 0.2–0.3 Mpa, thereby ensuring that the bubbles in the effluent from the flotation release valve are fine and uniform. 5.2.4 When the scum on the surface of the tank reaches 2/3 of the tank length, start the scum scraper to remove it. When discharging the scum, be careful to minimize the amount of water involved and avoid stirring, so as to prevent the scum from being carried away by the water flow and entering the biological treatment section. 5.3 Biochemical Unit 5.3.1 Closely monitor the quality of water entering the biochemical unit, paying attention to oil content and pH levels. Report any sudden changes promptly and identify the causes in order to adjust operations accordingly. 5.3.2 Closely monitor the properties of the sludge in the biochemical tank; it is strictly prohibited for the sludge to rise to the surface and be lost. In case this occurs, immediately reduce the amount of wastewater treated, and gradually restore normal operations once the sludge condition returns to normal. 5.3.3 Determine the sludge discharge time and amount based on the sludge settling ratio and sludge concentration. 5.3.4 Clean the return gap based on the operating conditions of the circular aeration tank to prevent sludge blockage. At this time, stop the water supply and perform cleaning for 5–15 minutes. After the cleaning is complete, close the air valve; once the sludge in the clarification zone has settled, resume water supply and return to normal operation. 5.3.5 Adjust the amount of return sludge based on the operating conditions of the push-flow aeration tank and the secondary sedimentation tank, to ensure stable water flow and efficient degradation of pollutants. 5.4 External Transfer Post 5.4.1 Maintain a stable liquid level in the collection tank based on the conditions of the water exiting the secondary sedimentation tank; ensure that the treated wastewater is transferred externally in a timely manner, and prevent the transfer pump from running dry. 5.4.2 Based on the reuse status of the treated wastewater from the main plant, open the wastewater reuse valves to facilitate its reuse. Chapter 6 Procedures and Steps for Starting Up and Shutting Down the Equipment 6.1 Startup Procedures 6.1.1 Preparations before startup ⑴ Organize the personnel on duty to study the startup plan and conduct relevant technical briefings. ⑵ Contact the electrical and instrumentation teams to inspect the system. ⑶ Prepare fire-fighting equipment, necessary tools, lubricants, etc. ⑷ Prepare the operation record sheet and production logbook. ⑸ Fill the flotation tanks, biochemical tanks, regulation tanks, etc. with water to test for leaks. ⑹ Cultivate and acclimate the activated sludge. ⑺ Prepare the polyaluminum and polyacrylamide solutions, and get ready for water quality testing. 6.1.2 Inspection ⑴ Check whether each pool and structure is clean enough to meet the usage requirements. ⑵ Inspect all pipelines, valves, oil collection facilities, and sewers. ⑶ Inspect the mechanical equipment; once it is confirmed to be in good condition, close all vents. 6.1.3 Commencement of operation ⑴ When the liquid level in the lifting tank rises to 3 meters, start the lifting pump to supply water to the oil separator and the regulating tank. ⑵ The wastewater is introduced into the flotation tank, while the dosing system and mixer are activated to inject the polyaluminum solution into the water inlet pipe. ⑶ After the water quality of the flotation effluent meets the requirements, it is introduced into the aeration tank and the plug-flow aeration tank; simultaneously, the blower is started to supply air to the plug-flow biological tank. ⑷ Once the water meets the standards, it is pumped out using the external transfer pump for discharge. ⑸ A submersible pump in the activated sludge tank returns sludge to the plug-flow bioreactor. 6.2 Shutdown 6.2.1 Collect all the floating oil from the oil separator, and stop the lift pump after the water in the tank has been pumped out. 6.2.2 Clean the scum in the flotation tank, stop feeding water and stopping the addition of chemicals. 6.2.3 After the flotation tank is shut down, reduce the speed of the aerator; if necessary, stop the blower used for forced aeration in the biological treatment process. 6.3.4 After shutting down in winter, drain the pumps, pipelines, etc. depending on the temperature conditions. Chapter 7 Emergency Plans 7.1 Emergency Plan for Heavy Rainfall During the summer, heavy rainfalls occur frequently. To ensure safe production and prevent accidents such as water overflowing from tanks or wells, the following emergency plan for heavy rainfall has been formulated. ⑴ Closely monitor the weather conditions, adjust the levels of the lift tanks, regulating tanks, and retention tanks in a timely manner, and adjust the amount of rainwater based on the specific situation. ⑵ When heavy rainfall requires the use of two or more lift pumps, two oil separation tanks should be used, and it is necessary to first ensure that the openings for the oil collection pipes in these tanks are oriented upward. Two flotation pumps need to be operated to ensure that rainwater can be discharged without any obstruction. To reduce the retention time of rainwater, the floating cross-line can be activated, following a process that involves a primary flotation pump and a secondary flotation tank. ⑶ Rainwater pollution is low, allowing it to be discharged directly; refer to the following process. ⑷ Discharge after flotation: Open valve 8 in the north valve well of the circular aeration tank and valve 9 at the inlet of the external transfer tank; close valves 1, 2, and 3 at the inlet of the circular aeration tank as well as valve 4 in the south part of the circular aeration tank. ⑸ After circular aeration, carry out external discharge: open valve 9 at the inlet of the external transfer tank, and close valves 6 and 7 at the inlet of the aeration tank. Note: All the operations mentioned above represent changes to the normal production process. Before making any adjustments, it is necessary to check the status of all valves to avoid accidental actions. 7.2 Emergency Plan for Fire and Explosion Incidents ⑴ Immediately call the emergency number 4879119, providing details of the location, area, and type of fire, and also inform the dispatch center and the workshop. ⑵ Stay at your posts, under the unified command of the squad leader, and take emergency fire-fighting measures. ⑶ Immediately close the inlet and outlet valves of the pool and tank to prevent the fire from spreading. ⑷ Use the fire extinguishers and other equipment available at the post to extinguish incipient fires. 7.3 Emergency Plan for Oil Spill from Oil Tanks ⑴ During heating: ① Immediately close the steam valve. ② Open the two bypass valves; if necessary, close the main steam valve or release some steam through the drain valve. ⑵ During oil transfer: ① Stop the pump immediately. ② Close the oil tank inlet valve. ③ Open the two bypass valves. ④ In special cases, some oil is drained through the dehydration valve. 7.4 Emergency Plan for Total Power Outage ⑴ Immediately close the outlet valves of all pumps. ⑵ Report to the head office dispatch team and the workshop, and inquire about the cause of the power outage and the time when power will be restored. ⑶ In the event of electrical issues at this site, please contact the electrical maintenance team immediately for inspection and repair. ⑷ During winter power outages, it is necessary to clean the oil pipelines in use. If the power outage lasts for an extended period, the water contained within the relevant pipelines and containers should be drained to prevent the pipelines and valves from being damaged by freezing. ⑸ The relevant personnel stayed at their posts and coordinated the work, resuming production immediately upon receiving the call. 7.5 Emergency Plan for Total Water Cutout ⑴ Contact the head plant’s dispatch team to inquire about the reason for the water cutout and the time when water supply will resume; if the cutout is expected to last for a long time, report to the workshop and adjust the various wastewater treatment units accordingly. ⑵ If the flotation system is dosing chemicals, stop the dosing pump as soon as possible. ⑶ The relevant personnel remain at their posts, carry out coordination work, and prepare to put the various wastewater treatment units into operation once water flow is available
Fault | Cause | Solution
--- | --- | ---
No flow or low flow rate | (1) Air in the pump | (1) Release air again
| (2) Impeller rotating in reverse | (2) Correct the impeller rotation
| (3) Blockage at the inlet | (3) Remove the blockage
| (4) Low water level at the inlet | (4) Raise the water level
| (5) Leakage at the inlet packing gland | (5) Tighten the bolts at the inlet connection points; compress or replace the packing
Interrupted water output | (1) Too low water level at the inlet | (1) Add more water
| (2) Severe blockage or air leakage at the inlet | (2) Remove the blockage; tighten the bolts at the inlet connection points
| (3) Sudden stop of the pump | (3) Start a backup pump to maintain operations; contact an electrician for repair
| (4) The inlet valve core has fallen off | (4) Repair the valve
Excessive packing leakage | (1) The packing is damaged | (1) Replace the packing
| (2) Wear of the shaft sleeve | (2) Repair or replace the shaft sleeve
| (3) Insufficient packing or inadequate tightening | (3) Add more packing or tighten the gland nuts
| (4) Bent shaft | (4) Straighten it out
| (5) Misalignment of the water seal ring | (5) Adjust the water seal ring
| (6) Excessive misalignment between the coupling gears | (6) Realign them
Smoke coming from the gland packing or overheating of the gland | (1) The gland is tightened too much | (1) Adjust the gland nut bolts
| (2) The gland is tilted and rubbing against the shaft | (2) Adjust the gland
| (3) Blockage in the water seal tube | (3) Clean the pipeline
Sudden increase in pressure | (1) Sharp decrease in water flow rate | (1) Reduce the number of pumps in operation or increase the reflux valve setting
| (2) Blockage in the outlet pipeline | (2) Remove the blockage
| (3) The outlet valve core has fallen off | (3) Repair the valve
Vibration of the pump | (1) Unbalanced pump base | (1) Level the base
| (2) Bent shaft | (2) Straighten it or replace it
| (3) Loose foundation bolts | (3) Tighten them
| (4) Damaged rotating parts | (4) Replace or repair them
| (5) Air in the pump chamber | (5) Drain the air
| (6) Excessive misalignment between the coupling gears | (6) Realign them
Too low current | (1) Inlet valve open too little or the valve core has fallen off | (1) Adjust the inlet valve opening
| (2) Air in the system | (2) Release the air
| (3) Excessive wear or damage to the impeller | (3) Replace the impeller
| (4) Faulty ammeter | (4) Replace or calibrate the ammeter
Too high current | (1) Gland packing is tightened too much | (1) Adjust the gland nut bolts
| (2) Motor running on one phase | (2) Contact an electrician for repair
| (3) Motor capacity exceeds the specified value | (3) Replace the motor or reduce the diameter of the impeller
| (4) Faulty ammeter | (4) Replace or calibrate the ammeter
Abnormal noises from the motor | (1) High load on the motor | (1) Reduce the motor load
| (2) Motor running on one phase | (2) Contact an electrician for repair
| (5) Use a backup pump | (5) Use a backup pump; according to relevant regulations, the direction of the rotation mark on the backup pump should be red on odd-numbered days and white on even-numbered days. ②Keep the lubricant level at the 1/2–2/3 mark on the oil sight gauge; whenever the level drops, top it up with fresh oil immediately. ③During routine inspections, its readiness as a backup should be checked according to the integrity standards. ④Maintain good hygiene and keep the backup pump clean and tidy. 4.1.5 Operation of the cross-flow inclined plate oil separator. (1) Check the preparation work. ①Clean the inside of the pool and cover it with the lid. ②Ensure that the inlet valve, steam valve, sludge discharge valve, and vent valve of the oil separator are airtight and leak-free, as well as easy to operate. ③Check that the oil collection pipe is not blocked and is in a position where oil is not being collected. ④The inclined plate should be placed correctly. ⑤The oil and sludge skimmer should be in good standby condition. ⑥Fire-fighting equipment should be complete and in good condition. ⑦Production tools and records are complete and in order. (2) Operation procedures and precautions ① Open the water inlet valve to introduce water into the tank. ②Adjust the water distribution valves in each area to ensure even water distribution. ③The thickness of the oil layer on the pond surface reached 30 mm, so an oil and sludge skimmer was activated to collect the oil. ④When collecting oil, turn the handwheel of the oil collection pipe so that the cut end of the pipe faces downward. Once the lower edge of this cut end reaches the oil surface, start the oil and sludge skimmer to scoop the oil floating on the surface into the oil collection pipe for recovery. During operation, make sure the orientation angle of the oil collection pipe is appropriate, so as to prevent a large amount of water from being collected in it. ⑤After collecting the oil, be sure to keep the opening of the oil collection pipe pointing vertically upward, to prevent large amounts of water from overflowing into the pipe during heavy rain or high water levels, which could cause the oil collection tank to overflow. ⑥When the oil on the surface of the pool condenses and becomes less fluid, open the steam valve to melt the oil. ⑦The sediment in the pool is removed once a month; prior to removal, contact the relevant department to arrange for the collection of the sediment. ⑧If the oil content in the effluent is abnormal or blockage of the inclined plate is detected, gradual venting and flushing should be carried out. (3) Abnormal conditions and handling Abnormal conditions Causes Handling methods Excessively high oil content in the effluent (1) Emulsification caused by alkaline residues in the incoming water (2) Excessive oil content in the incoming water (3) Too thick oil layer with excessive sludge at the bottom of the tank (4) Excessive treatment volume (1) Send it to the regulation tank and contact the dispatch team for adjustment. (2) Collect oil and sludge in a timely manner. (3) Reduce the water inflow volume, or activate multiple tanks. Oil skimming and clumping: The temperature is too low and there is a high amount of heavy oil; turn on steam for heating. (4) Shutdown procedures: ① Close the water inlet valve. ②Cut off the power to the oil and sludge scraper. ③Open the sludge discharge valve to drain the water, and then clean and perform maintenance. 4.1.6 Operation of the oil and sludge skimmer (1) Inspection and preparation work ① Contact an electrician to check the power supply and ensure that the motor is safe and reliable. ②Check all bolts to ensure they are not loose. ③Check whether the chain is stuck and whether the scraper is in good condition. ④Check whether the lubricant level is within the required range. ⑤Clear the surrounding clutter. (2) Start: Press the start button. (3) Normal operation: ① Regularly check the motor temperature; it should remain within the allowable range. ②The gearbox should make no abnormal noises. ③Check whether the scraper is stuck and whether it moves up and down smoothly and reliably. ④The oil and sludge scraper should operate smoothly, without any jamming or deviation. ⑤The operating time is determined based on the thickness of the oil layer. ⑥In the event of a broken chain, machine jamming, or any other serious abnormality, the machine must be stopped immediately and the station notified. (4) Shutdown ① Press the stop button. ②The scrapers must all come to a stop on the water surface. 4.1.7 Operation of the regulation tank: (1) When the water quality parameters such as alkalinity and COD are too high, open the inlet valve of the regulation tank to collect the wastewater with high concentrations there for quality adjustment. ⑵ Based on the upstream water inflow volume and water quality, the discharge valve of the regulating tank is opened at the appropriate time to allow water to flow into the lift tank in a uniform manner and at a low flow rate. ⑶ The regulation tank should normally be kept empty, so that in the event of abnormal conditions (heavy rainfall, high-concentration wastewater), there is sufficient capacity available for regulation. 4.1.8 Operation of the sludge pump (Roths pump) (1) Preparation ① After the new pump is installed, before starting it up, fill the gearbox and reducer with L-AN46, an oil designed for full-loss systems. ②Check the sealing of all pipeline flanges and joints to ensure they are tight and leak-free. ③The pump should be filled with the fluid to be transported before starting. ④Before starting, the valves in the suction and discharge pipelines should be fully opened; it is strictly prohibited to start with the valves closed. ⑤Verify the motor direction; start the motor only after the direction is correct. ⑥Open the valve of the oil tank into which the waste oil is being poured. ⑦Before starting the pump, purge the pipeline; stop once gas is detected. (2) Operation ① After starting the pump, pay attention to the temperature of the bearings and the pump body. ②If abnormal noises from the pump and motor are detected (or if the ammeter needle rises rapidly), the machine should be stopped immediately for inspection. ③If a fault occurs in the piping system, the machine should be stopped immediately to resolve the issue. ④Check the liquid level in the oil collection tank and the amount of oil collected from time to time. (3) Shutdown ① After turning off the motor, close the inlet and outlet valves of the pump. ②Before shutting down the machine, never close the outlet valve first, as this can easily damage the pump. ③After stopping the pump, purge the pipeline with steam. ④Faults and troubleshooting methods. (4) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②Keep the lubricant level at the 1/2–2/3 mark on the oil sight gauge; whenever the level drops, top it up with fresh oil immediately. ③During routine inspections, its readiness as a backup should be checked according to the integrity standards. ④Maintain good hygiene and keep the backup pump clean and tidy. 4.1.9 Operation of the oil tank (1) Inspection and preparation ① The access holes for the steam and water valves of the oil tank should be airtight and leak-free, as well as easy to operate. ②The indicator gauge is flexible and easy to use, with accurate readings. ③All debris inside and outside the tank area has been removed. ④Fire-fighting equipment and breathing valves must be complete and in good condition. (2) Oil inlet operation for the oil sludge tank: ① Open the oil inlet pipeline and the steam valve, and perform steam purging; close them once steam is observed at the outlet. ②Check the oil level in the tank. ③Start the sludge pump to transfer oil into the tank, making sure that the oil level in the tank does not exceed the safe level. ④After stopping the oil supply, turn on the steam to purge the pipeline until steam is observed. Once the purging is complete, close all relevant valves and take measurements while keeping a record of them. (3) Heating and dehydration ① Turn on the steam trap, then start steam heating, maintaining the temperature at 70–85°C. ②During the heating process, the steam flow rate should not be too high; regular inspections must be carried out to prevent contaminated oil from spilling over the tank. ③After heating is complete and 8 hours of settling have passed, the dehydration valve is opened to start the dehydration process. During this process, the personnel on duty must check regularly and close the dehydration valve immediately upon detecting any oil. ④During dehydration, the valve should not be opened too wide to prevent excessive oil from entering. ⑤Once the tank is full, and if the water content in the contaminated oil is less than 5%, contact the dispatch team to transfer the oil to another tank or facility, and keep proper records. (4) Oil delivery ① Conduct measurements and take records before oil delivery. ②Contact the oil receiving unit to clean the lines and switch the valves. ③Open the outlet valve of the oil tank and start the oil transfer pump to deliver oil. ④After the oil delivery is complete, stop the pump, close the outlet valve of the oil tank, and record the measurements taken after the delivery. ⑤Complete the task, report to production scheduling and the station, and switch the valve. (5) Calculation of the oil delivery volume: Formula: W = D × (V_before – V_after) × (1 – R) Where: W is the net weight of the oily waste delivered (in tons); R is the water content of the oily waste; V_before is the volume of the oily waste in the tank before delivery (in cubic meters); V_after is the volume of the oily waste in the tank after delivery (in cubic meters); D is the density of the oily waste (in tons per cubic meter). (6) Precautions: ① Regular inspections should be carried out during the dehydration process of the oily waste. ②After the contaminated oil is dehydrated, if the test results are unsatisfactory, repeat the dehydration process. ③The oil inlet height and heating temperature must not exceed the specified values. ④Strangers are strictly prohibited from entering the oil tank area, and a fire permit is required for any welding work. ⑤Take measures to prevent freezing and condensation in winter. ⑥Maintain good environmental hygiene. (7) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②Keep the lubricant level at the 1/2–2/3 mark on the oil sight gauge; whenever the level drops, top it up with fresh oil immediately. ③During routine inspections, its readiness as a backup should be checked according to the integrity standards. ④Maintain good hygiene and keep the backup pump clean and tidy. 4.1.10 Sludge Recovery Operations (1) Sludge Recovery Management ①Sludge recovery is carried out in accordance with the regulations set by the head office, under the unified coordination of the control room. ②The contaminated oil is transferred as arranged by the head office’s dispatch or planning department; after being signed off by the supervisors of that department, notification is sent to the wastewater treatment station, which then receives it in accordance with the specified quantity and quality standards. ③Once the storage tank is filled, the sewage treatment station is responsible for heating it. The control room coordinates with Station 1 for oil handling and the sewage treatment station to carry out the oil transfer process; the sewage treatment station starts the pumps to transfer the oil, which is then received by Station 1. After the transfer is complete, the pumps are stopped and the tank is purged with steam, ready for future use. (2) Sludge oil recovery operation: Process flow for sludge oil recovery: Equipment: Submersible pump, model 40LY250, flow rate: 10 m3/h, head: 90 m, power: 11 Kw; Sludge oil tank, dimensions φ1400*3500, capacity: 5 m3. Figure 1: Flow diagram for sludge oil recovery. (3) Operation of the submersible pump: (1) Preparation work: ① Check the tightness of all pipeline flanges and connections; they must be leak-free. ②Check that all oil and steam valves are airtight, leak-free, and operate smoothly. ③Check that all indicator instruments are flexible to use and provide accurate readings. ④Clean all debris inside and outside the oil tank. (2) Oil tank filling operation: ① Upon receiving the notification, check the liquid level in the tank, open the manhole access, and transfer the dirty oil from the unloading vehicle into the dirty oil tank. ②Regularly check the liquid level in the oil sludge tank, making sure that the level inside the tank does not exceed the safe height. ③After stopping the oil inflow, close the oil inlet manhole properly. (3) Oil tank heating operation ① Open the line from the steam outlet condensate to the sewage well. ②Turn on the steam line for heating, and control the oil temperature at 70–85°C. ③Check the temperature and liquid level inside the tank to prevent overflow caused by excessive temperature. (4) Oil transfer operations ① Conduct gauge checks and make records before receiving oil. ②Contact the oil receiving unit to purge the pipeline; once steam is detected at the outlet, switch the oil transfer valve. ③ Open the outlet valve of the sludge pump and start it to transfer the sludge. ④After the transfer of oil is complete, stop the pump, close the outlet valve of the oil tank, and prepare the measurement records after the oil delivery. ⑤Notify the production scheduler and the oil station to contact the team responsible for purging the oil pipelines, and stop the steam supply once steam is detected at the outlet. 4.2 Flotation Posts 4.2.1 Operation of flotation pumps, (this procedure applies to flotation pumps, air flotation circulation pumps, and other mechanical-sealed pumps.) ） (1) Preparation ① Contact an electrician to check the power supply and ensure that the motor is safe and reliable. Press the motor’s start button briefly to test whether its rotation direction is correct; rotation from the top of the motor toward the pump should be in a clockwise direction. The testing time should be short to prevent dry wear of the mechanical seal. ②Check whether the bolts connected to the outside of the pump are complete and firmly tightened. ③Check the water levels in the primary and secondary flotation sumps to ensure they are within the specified range. ④Open the inlet valve fully. ⑤Close the outlet valve. ⑥Open the exhaust valve to fill the entire pump with liquid, and close it once it is full. ⑦Spin the pump (2–3 weeks) to allow the lubricant to reach the mechanical seal faces. (2) Start-up ①Start the motor and check whether the pump rotates in the correct direction. ②By adjusting the opening degree of the outlet valve, the pressure (02–0.4 Mpa) and current (20.5–35.5 A) remain within the specified range. (3) Operation: ① After the pump is started, carry out operation and maintenance strictly in accordance with the \"five-step method\" for pumps (listen, touch, check, observe, compare). ②Check for shaft seal leakage; under normal conditions, the mechanical seal should leak less than 3 drops per minute. ③Check the motor; the bearing temperature rise should be ≤70°C. ④Check whether the pressure, flow rate, and current are within the specified range. (4) In the event of the following situations that cannot be resolved, switch immediately and report. ①The current is extremely high. ②Severe vibration and abnormal noises from the pump. ③The electrical system is smoking or on fire. ④A serious abnormality has occurred. (5) Stop the pump: ① Close the outlet valve. ②Press the stop button. (6) Common causes of faults and troubleshooting methods. Fault symptoms, possible causes, and troubleshooting methods: The water pump does not deliver water. (1) The inlet valve is not open, the inlet and outlet pipes are blocked, or the impeller in the flow channel is blocked. (1) Check and remove obstructions. (2) The motor is running in the wrong direction; it has a low speed due to a missing phase. (2) Adjust the motor direction and tighten the motor connections. (3) Air leakage in the suction pipe. (3) Tighten all sealing surfaces to remove air. (4) The pump is not filled with liquid; there is air inside the pump chamber. (4) Open the pump cover or the exhaust valve to release air. (5) Insufficient imported water supply, excessive head pressure, and valve leakage. (5) Stop the machine for inspection and adjustment. (6) Excessive pipeline resistance, improper pump selection. (6) Reduce pipe bends and select a new pump. Insufficient water pump flow (7): Blockage in the pipes, pump flow channels, and impeller area, scale deposition, and insufficient valve opening. (7) Remove the blockage and readjust the valve opening. (8) Low voltage (8) Voltage stabilization (9) Impeller wear (9) Replace the impeller. Excessive power (1) Operating beyond the rated flow rate (1) Adjust the flow by closing the outlet valve. Too high suction lift (2) Reduce it. (3) Pump bearing wear (3) Replace the bearings. Fault symptoms, possible causes, and solutions: Noise and vibration (1) Unstable pipeline support (1) Stabilize the pipeline. (2) Gas mixed in the liquid (2) Increase the suction pressure to expel gas. (3) Cavitation occurring (3) Reduce the vacuum level. (4) Damaged bearings (4) Replace the bearings. (5) Motor operating under overload and overheating conditions (5) Make adjustments. Motor overheating (1) Excessive flow rate, resulting in overload operation (1) Close the outlet valve. (2) Rubbing/scratching (2) Check and eliminate the cause. (3) Damaged motor bearings (3) Replace the bearings. (4) Insufficient voltage (4) Stabilize the voltage. Pump leakage (1) Wear of the mechanical seal (1) Replace it. (2) Holes or cracks in the pump body (2) Weld or replace the pump body. (3) Uneven sealing surface (3) Repair it. (4) Loose installation bolts (4) Tighten them. 4.2.2 Operation of flotation dosing pumps (metering pumps) (1) Preparations before starting the pump: ① Check whether the bolts at all connection points are tight. ②An appropriate amount of engine oil is injected into the transmission case depending on the ambient temperature and the temperature under conveying conditions. ③Rotate the pump (for 2–3 weeks), moving the plunger back and forth several times to ensure there is no sticking, then align the pump’s stroke zero position with the zero mark on the adjustment gauge. ④Check the motor wiring to ensure the pump rotates in the specified direction. ⑤Prepare the solution in the tank (aluminum hydroxide chloride). ⑥Start the motor, and the pump begins to operate. (2) Precautions during operation: ① If abnormal noises are heard while the pump is running, it should be stopped to determine the cause, and the station should be informed. ②When the leakage rate exceeds 15 drops per minute, the packing gland should be tightened appropriately. ③When the temperature at the plunger packing rises rapidly, the pump should be stopped, the packing gland should be loosened, the cause should be investigated, and the pump can be put back into operation only after the issue is resolved. ④The temperature of all areas must not exceed 65°C. (3) Parking ① Cut off the power supply to stop the motor from operating. ②Close the valve on the inlet pipeline, but be sure to open it before starting the pump. (3) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②Keep the lubricant level at the 1/2–2/3 mark on the oil sight gauge; whenever the level drops, top it up with fresh oil immediately. ③During routine inspections, its readiness as a backup should be checked according to the integrity standards. ④Maintain good hygiene and keep the backup pump clean and tidy. 4.2.3 Operation of the flotation cell (1) Inspection and preparation work ① Remove debris from the chemical dosing tank, dissolver tank, flotation cell, and around the valves. ②Check whether the valves associated with the position are airtight, leak-free, and functional. ③Check whether the instruments for various indicators are sensitive and accurate. ④The slag scraper, automatic control equipment, and suction valve are in good condition and ready for use. ⑤Prepare an aluminum hydroxide solution with a concentration of 50 mg/l in the dosing tank. ⑥Water is introduced into the flotation tank to the specified level. ⑦Prepare the production record report. (2) Operation ① Inlet valve and outlet valve of the air flotation tank. ②Open the inlet and outlet valves of the air flotation circulation pump. ③Start the dosing pump to inject the chemical solution into the pipeline before the air flotation pump. ④Adjust the releaser to produce uniform and fine bubbles. (3) Precautions during operation. ①Adjust the dosage of chemicals flexibly according to water quality changes; the typical addition concentration is 30–50 mg/l. ②Regularly check the chemical dosing pipeline to ensure it remains unobstructed. ③Maintain the pressure in the air flotation tank at 0.2–0.3 Mpa. ④Maintain regular communication with the oil separation team to ensure a steady and even water flow. ⑤When the scum on the surface of the tank reaches 2/3 of the tank length, start the scum scraper to remove it. When discharging the scum, the water level should be kept slightly above the overflow weir; care should be taken to minimize the amount of water involved and to avoid vigorous stirring, so as to prevent the scum from being carried away by the water flow and entering the biological treatment system. ⑥The sludge at the bottom of the tank is cleaned periodically, depending on the effluent from the air flotation tank and its operating time. (4) Shutdown procedure: ① Stop the chemical dosing pump and close the chemical feed valve. ②Stop the air lift pump and circulation pump, and open the vent valve of the dissolved air tank. ③Collect the remaining scum. (5) General methods for troubleshooting. Sequence Number, Fault, Cause, Solution: 1. Bubbles are large and uneven – (1) The air flotation circulation pump does not start; (2) The air flotation circulation pump keeps running. Contact the maintenance team for the automation system. 2. Excess oil content in the effluent – (1) High oil content in the effluent from the oil separator; (2) Insufficient dosage of chemicals or blocked pipelines; (3) Excessive accumulation of scum; (4) The air flotation process is not operating or keeps running. (1) Contact the team to improve control measures; (2) Repair the chemical dosing system or increase the dosage; (3) Remove scum promptly; (4) Carry out repairs promptly. 4.2.4 Operation of the flotation dissolved air tank: 1) Operational adjustments – ① Maintain pressure at 0.2–0.3 MPa; the optimal pressure for achieving good flocculation results is 0.25 MPa. ②If the pressure is not within the controlled range, adjust the relief valve or the outlet valve of the flotation pump to bring the pressure back within the controlled range. 2) Precautions (Operation of the 1# Dissolution Tank for Secondary Flotation) ① When the flocculation effect is poor, it is not possible to adjust the flocculation by using the manual mode in the electrical control cabinet; instead, the pressure must be adjusted according to the method specified by the ultrasonic water level automatic control system, so as to keep it within the desired range. ②Only if the ultrasonic water level automatic control system fails or other faults occur should the manual mode be used to ensure the effectiveness of flocculation. 4.2.5 Operation of the slag scraper (1) Preparation ① Contact an electrician to check the electrical components. ②Check the bolts in all areas; there should be no looseness. ③Check that the oil quality and quantity meet the requirements. (2) Start: Press the start button to activate the slag scraper. (3) Operation ① Check whether the slag scraper moves at a steady speed. ②The sound of the gearbox should be normal. ③Check whether the scraper is stuck and if the water depth is appropriate. (4) Stop immediately in the following situations. ①After pressing the start button, the slag scraper does not operate. ②The machine got stuck and other serious abnormalities occurred. (5) Stop: After all the scrapers of the slag scraper have been raised above the water surface, press the stop button. 4.2.6 Operation of the scum pump (1) Preparation ① Contact an electrician to check whether the power supply and motor are safe and reliable, and verify the motor’s rotation direction. ②Check the bolts connecting the pumps and pipelines; they must be complete, tight, and secure. ③Check the sealing of all pipeline flanges and joints, regularly inspect whether the filters are unobstructed, and remove debris around the pump. ④Check whether the dewatering valve of the slag tank is closed and whether the inlet valve on the slag tank is open. ⑤Inject liquid into the forward pump before starting (for the first start-up or after purging). ⑥Open the inlet valve and the outlet valve. ⑦Turn the pump 2-3 times. (2) Start up: ① Start the motor and check whether the pump rotates in the correct direction. ②Operate and maintain the pump strictly in accordance with the \"five-step method\" for pumps (listen, feel, check, observe, compare). (3) Stop the pump: ① Cut off the power supply to stop the motor from running; ② Close the inlet valve, but be sure to open it before restarting the pump. (4) Precautions: ① After the pump is started, it should operate smoothly without any abnormal noises; otherwise, it should be stopped to determine the cause, and the station should be informed. ②Check the temperature of all areas; it must not exceed 65°C. ③Operation without a load is strictly prohibited; if the output is low, the cause should be checked. ④The inlet valve and outlet valve must not be closed during the start-up, shutdown, or operation of the pump. ⑤After removing the slag in winter, purge with steam to prevent pipeline freezing and cracking. 4.3 Biochemical Treatment Unit 4.3.1 Operation of the circular aeration tank (1) Preparation ① Remove any debris inside and outside the biochemical treatment unit, and close the sludge discharge valve. ②Check that the aerator and electrical control units are in good standby condition. ③Cultivate active sludge properly and control various influent parameters. ④Prepare disodium hydrogen phosphate and urea. ⑤Prepare the sampling device for testing. ⑥Prepare the production tools and operation records. (2) Shipment operation ① Slowly open the water inlet valve to introduce water into the tank. ②Start the aerator. ⑶ Precautions: ① Closely monitor water quality and sludge properties (analyze the sedimentation ratio every two hours, and analyze dissolved oxygen every four hours). If any abnormalities are detected, report them to the station promptly, identify the cause, and adjust the operations accordingly. ②Pay attention to adjusting the inlet valve; sludge backflow is strictly prohibited. In case of sludge backflow and loss, report immediately, reduce the processing volume, and gradually resume normal operation once the sludge flow returns to normal. ③The sludge discharge time and amount are determined based on the settling ratio and the sludge concentration (controlled at 3–5 g/l). During sludge discharge, close the water inlet valve and shut down the aerator and blower for 30 minutes; then open the sludge discharge valve to release the sludge, paying attention to the level of water as this process takes place. When the water level drops to the expected level, close the sludge discharge valve, keeping the sludge settling ratio at around 25%. ④Based on the conditions observed during operation, purge the return gap to prevent sludge blockage (stop water inflow during purging, open the air valve for the return gap, and purge for 5–15 minutes; after purging is complete, close the air inlet valve. Once the sludge in the clarification zone has settled, open the water inlet valve to resume normal operations). ). ⑤Based on the analytical tests, phosphates (or other artificial nutrients) are added per shift in accordance with the process requirements. ⑷ Shutting down procedure: ① Slowly close the water inlet valve. ②Tingyun aeration machine. ③When the biochemical tank is out of use for more than a week, nutrients should be added to it as required to sustain the sludge. If it is necessary to clean the aeration tank, the activated sludge can be transferred to another tank; after cleaning, it can be returned to the original tank. (In cases of long-term disuse, the sludge should be stored by allowing it to settle naturally in order to preserve the microorganisms.) (5) Causes of common faults and their solutions. Sequence Number, Fault, Cause, Solution: 1. Sludge floating: (1) Deterioration of water quality; (2) Sudden rise in water temperature; (3) Blockage of the return gap; (4) Excessive inflow of water. Solutions: (1) Take measures to improve water quality; (2) Add fresh water; (3) Clean the return gap; (4) Adjust the water flow rate. 2. Sludge deposition: (1) Low return flow rate; (2) Low rotation speed of the aerator. Solutions: (1) Adjust the return gap; (2) Increase the rotation speed of the aerator. 3. Decrease in sludge volume: (1) Poor water quality; (2) Insufficient oxygen supply; (3) Insufficient nutrients. Solutions: (1) Improve water quality; (2) Increase the rotation speed of the aerator; (3) Add more nutrients to support sludge growth and supply fresh sludge. 4.3.2 Operation of the aerator: (1) Preparations before startup: ① Contact an electrician to check the power supply, ensure that the control system is reliable and the direction of operation is correct, then supply power. ②Keep the lubricating oil at the gauge scale line. ③Turn the shaft 2–3 weeks to check for any sticking. ④Open the inlet valve to introduce wastewater into the tank, ensuring that the impeller of the aerator is at the desired submersion depth (usually 40 mm); open the return window to 1/3–1/2 of its capacity. (2) Start-up ① Adjust the governor knob so that the pointer points to the “0” position. ②Press the start button to activate the aerator. ③Adjust the aerator speed based on the dissolved oxygen in the effluent and the BOD5 content in the influent. (3) Operation: ① After starting up, carry out maintenance tasks strictly in accordance with the \"five-step method\" of listening, touching, checking, observing, and comparing. ②The oil temperature of the gearbox is <65°C, and the bearing temperature is <70°C. ③Check for noise and vibration. (4) Parking: Press the parking button. (5) Standby ① Rotate the standby pump in accordance with relevant regulations; the orientation of the rotation mark should be such that it faces upward in red on odd-numbered days, and upward in white on even-numbered days. ②During routine inspections, its readiness as a backup should be checked according to the integrity standards. ③Maintain good hygiene and keep the backup pump clean and tidy. 4.3.3 Operation of the push-flow biochemical system (1) Preparation work. ①Remove debris inside and outside the tank, and close the drain valve as well as all bypass valves. ②Check whether the blower and sludge return pump are in good standby condition. ③Check whether the sludge discharge valve of the secondary sedimentation tank and the valves of each unit in the plug-flow aeration tank are flexible and functional. ④Check the air supply pipeline for push-flow aeration for any air leaks. ⑤Prepare the sampling device for testing. ⑥Prepare the production tools and operation records. (2) Shipment operation ① Slowly open the water inlet valve to introduce water into the tank. ②Start the blower. ③Adjust to ensure even air supply to each unit. ④After the water exits the secondary sedimentation tank, adjust the sludge discharge valves of the tank to ensure uniform sludge discharge from each tank. ⑤Regularly adjust the return flow rate of sludge. (3) Shutdown procedure ① Slowly close the water inlet valve. ②Shut down the blower. 4.3.4 Operation of the blower (1) Preparation for startup ① Check whether the pipes, silencers, and filter devices are in proper condition, whether there are any residual substances in the pipes, and whether all bolt connections are tight and secure. ②Check whether the bearing housing is filled with grease. ③Check whether the indicator is at the “0” position. ④Check the power supply to ensure that the wiring is safe and correct, that the voltage is normal, and that all switches and buttons are flexible, reliable, and functioning properly. ⑤Run the pump for 2–3 weeks, and check for any blockages or abnormal noises. ⑥There is a blower with cooling water; open the cooling water valve. ⑦Press the jog button to test operation and check the fan direction. (2) Startup ① Close the inlet and outlet valves (i.e., start the machine under no-load conditions; the outlet valve does not need to be closed). ②Start the motor. ③After starting up, pay attention to the vibration and noise; if anything abnormal is detected, stop the machine immediately for inspection and report the situation for prompt handling. ④Once the motor reaches its rated speed and there are no abnormalities in any of its components, open the inlet and outlet valves as soon as possible. At the same time, pay attention to the ammeter reading, ensuring that it remains below the motor’s rated current value. (3) Inspection after startup ①Check for any abnormalities in internal sound and vibration. ②Check whether there are any abnormalities in the motor load. ③Check for any gas leaks at all connections. ④There is a blower for cooling water; check that the cooling water flow is unobstructed to prevent any interruptions. (4) Inspection during operation ① Record wind pressure, air volume, bearing temperature, etc. at regular intervals. ②During operation, pay constant attention to the sound and vibration levels; if surge noises or excessive vibration are detected, stop the machine immediately for inspection and report to the workshop. ③When the radial amplitude at the bearing area exceeds 0.06 mm, the machine should be stopped for maintenance. ⑸Pressure and air volume adjustment: ① If the pressure is high and the air volume is low, slowly open the outlet valve until the required conditions are met ； ②If the pressure is high and the air volume is large, the inlet valve should be closed partially ； ③If the pressure is low but the air volume is high, the outlet valve should be closed gradually until the desired level is reached ； ④If the pressure is low and the air volume is small, the inlet valve should be opened wider until satisfactory results are achieved. ⑹Parking ① When parking, first press the stop button, then quickly close the inlet and outlet valves. ②During the shutdown process, pay attention to whether there are any abnormal noises inside the machine and whether the shutdown time is unusually short. ③For blowers with cooling water, close the cooling water valve. ④ During long periods of shutdown, rotate the fan rotor 180 degrees at intervals. ⑺Causes of Faults and Troubleshooting Methods Fault Condition Cause Solution Excessively high bearing temperature Excessive oil injection Drainage Bearing overheating and damage (1) Insufficient oil amount (2) Poor quality of oil (1) Add water (2) Change the oil ⑻ Spare pump ① Rotate the spare pump in accordance with relevant regulations; the rotation mark should be such that it faces upward: red on odd-numbered days, and white on even-numbered days. ②During routine inspections, its readiness as a backup should be checked according to the integrity standards. ③Maintain good hygiene and keep the backup fans clean and tidy. 4.4 Transfer Pump Operation 4.4.1 Operation of the transfer pump (see Section 1.4, Operation of the Lift Pump) 4.4.2 Operation of the sludge return pump (1) Preparation work ① Use a megohmmeter to check that the insulation resistance between the motor stator windings and ground is not less than 1 megohm. ②Check that the cable is free of damage or breaks, and that it is properly grounded. ③Starting is not allowed when the voltage exceeds 10% of the rated value. (2) Start-up ①Open the outlet valve. ②Turn on the power and jog the motor. ③Pay attention to checking the operation of the pump, such as whether there are any noises, and check the current and voltage conditions of the motor while the pump is running. (3) Parking ①Close the valve. ②Turn off the power supply to stop the motor. 4.4.3 Three-Phase Sludge Dewatering System 4.4.3.1 Operation of Horizontal Screw Discharge Sedimentation Centrifuge (1) Preparation ① The exposed fabric parts of the centrifuge and all bolts should be tightened. ②Check the flexibility of the drum; turn it 2–3 times. It should rotate smoothly, without any abnormal noises caused by jamming or sticking, and it should rebound when at rest. ③Click to check whether the motor rotates in the correct direction. (2) Start-up ① Set the frequency of the inverter to the specified value. ②Press the start button. ③Once the motor current or frequency reaches the set value, slowly open the feed valve. ④It is advisable to regularly adjust the feed valve to keep the quality of the effluent water from becoming too dark. ⑤Start the chemical dosing pump simultaneously with feeding. (3) Shutdown ①Stop the dosing pump. ②Close the feed valve. ③Open the clean water valve and flush for 10 minutes. ④Shut off the clean water valve and stop the machine after 5 minutes. (4) Precautions: It is not allowed to flush the centrifuge with clean water after it has been shut down. (5) Common faults of centrifuges and troubleshooting methods
Serial Number | Fault Symptoms | Possible Causes | Solutions
1 | Excessive overheating of the main bearing | 1. Too much grease applied to the bearing 2. Tight fit between bearings 3. Damaged bearing (inflexible rotation) | 1. Stop applying grease and run the machine at low speed for a while 2. Repair or grind the bearing housing to achieve a J7/h6 fit 3. Replace the bearing
2 | Severe vibration when the machine is not in operation | 1. Blockage in the drum and screw conveyor 2. Loose connection flanges of the differential 3. Misalignment of the drum’s scale lines during maintenance, resulting in loss of dynamic balance 4. Severely worn screw blades 5. Loose bolts connecting the main unit and motor | 1. Remove deposits 2. Check the concentricity of the differential and replace damaged parts 3. Realign the scale lines 4. Repair the screw blades 5. Tighten the bolts
3 | Severe vibration during feeding | 1. Uneven feeding or impact forces 2. Belt slippage, causing blockage in the drum | 1. Ensure even feeding 2. Remove deposits and readjust the belt
4 | Sediments cannot be discharged; the clear liquid flows normally | 1. Reverse rotation direction 2. Too loose belt, causing blockage in the drum 3. Blockage in the feed pipe (or accumulation of material inside the drum) | 1. Rotate in the correct direction 2. Adjust the belt and remove deposits 3. Clear the pipes of deposits
5 | Neither the solid nor liquid phases are discharged | 1. Blockages in the valves and feed pipes 2. Blockage at the outlet of the feed hopper | 1. Remove deposits from the pipes or replace the valves 2. Remove deposits from the feed hopper
4.4.3.2 Operation of the chemical dosing tank
(1) Preparation work ① Remove any debris from the surrounding area. ②Check for leaks in pipelines, valves, etc. (2) Operation: ① Open the valves before and after the sand remover. ②Open the valve for feeding into the tank. ③Start the submersible sewage pump. ④Open the outlet valve of the submersible pump. ⑤Start the chemical dosing pump simultaneously with the submersible sewage pump to add chemicals to the dosing tank. ⑥After filling the tank, open the air valve and stir for 5–10 minutes. ⑦Feed the degassing fan 30 minutes after the wind has stopped. (3) Shutdown ① Close the pump outlet valve. ②Stop the pump. ③Stop adding chemicals, and close the valves of the sand remover and the chemical feed tank. 4.4.3.3 Operation of the dosing machine (1) Preparation work ① Check that all bolts are securely tightened. ②Check whether the lubricant level in the gearbox meets the requirements. ③Rotate the shaft for 2–3 weeks and check whether there is any jamming in the gearbox. (2) Start-up ① Press the start button to activate the mixer. ②Observe the startup of the mixer slurry. (3) Operation ① Check whether the lubricating oil is normal. ②Check the gearbox and other components for oil leaks. ③Check for abnormal temperatures, noises, or vibrations; if any abnormalities are detected, stop the machine immediately to address the issue or report it. (4) Causes and solutions for common faults. Serial number, Fault, Cause, Solution: 1. Mixer does not move: 1. Power outage; 2. Problem with the reducer. 1. Contact an electrician to handle it; 2. Perform maintenance. 2. Excessively high temperature: 1. Insufficient lubricant level; 2. Damaged lubricant; 3. Incorrect lubricant grade; 4. Damaged gearbox components. 1. Add lubricant to the required level; 2. Replace the lubricant with the correct grade; 3. Change the lubricant; 4. Perform maintenance. 3. Abnormal noises: 1. Motor failure; 2. Damaged reducer bearings. 1. Perform maintenance; 2. Perform maintenance. Chapter 5: Methods for adjusting operations in key positions. 5.1 Oil separation position. 5.1.1 Regularly operate the grid cleaner to remove debris from the incoming water. 5.1.2 Adjust with acid based on the pH of the incoming water to prevent stress on subsequent treatment units. 5.1.3 Based on the water quality and quantity of the water supplied by the head plant, recycled water, regulating tanks, and adjustment ponds are used for regulation to ensure stable operation of the oil separator. 5.1.4 Regularly remove surface oil from the oil separator and regulating tank. 5.1.4 Ensure proper dehydration of the oily sludge tanks; once the water content of the oily sludge meets the required standards, it should be promptly transferred to the relevant units for treatment. 5.2 Flotation Unit 5.2.1 Treat the sewage after oil separation based on the conditions of the incoming water, to ensure stable operation. 5.2.2 Add flotation reagents as appropriate, and use air flotation to remove emulsified oil from wastewater. 5.2.3 Adjust the flotation tank release valve, or control the outlet pressure of the air flotation pump, to maintain the pressure in the dissolved air tank at 0.2–0.3 Mpa, thereby ensuring that the bubbles in the effluent from the flotation release valve are fine and uniform. 5.2.4 When the scum on the surface of the tank reaches 2/3 of the tank length, start the scum scraper to remove it. When discharging the scum, be careful to minimize the amount of water involved and avoid stirring, so as to prevent the scum from being carried away by the water flow and entering the biological treatment section. 5.3 Biochemical Unit 5.3.1 Closely monitor the quality of water entering the biochemical unit, paying attention to oil content and pH levels. Report any sudden changes promptly and identify the causes in order to adjust operations accordingly. 5.3.2 Closely monitor the properties of the sludge in the biochemical tank; it is strictly prohibited for the sludge to rise to the surface and be lost. In case this occurs, immediately reduce the amount of wastewater treated, and gradually restore normal operations once the sludge condition returns to normal. 5.3.3 Determine the sludge discharge time and amount based on the sludge settling ratio and sludge concentration. 5.3.4 Clean the return gap based on the operating conditions of the circular aeration tank to prevent sludge blockage. At this time, stop the water supply and perform cleaning for 5–15 minutes. After the cleaning is complete, close the air valve; once the sludge in the clarification zone has settled, resume water supply and return to normal operation. 5.3.5 Adjust the amount of return sludge based on the operating conditions of the push-flow aeration tank and the secondary sedimentation tank, to ensure stable water flow and efficient degradation of pollutants. 5.4 External Transfer Post 5.4.1 Maintain a stable liquid level in the collection tank based on the conditions of the water exiting the secondary sedimentation tank; ensure that the treated wastewater is transferred externally in a timely manner, and prevent the transfer pump from running dry. 5.4.2 Based on the reuse status of the treated wastewater from the main plant, open the wastewater reuse valves to facilitate its reuse. Chapter 6 Procedures and Steps for Starting Up and Shutting Down the Equipment 6.1 Startup Procedures 6.1.1 Preparations before startup ⑴ Organize the personnel on duty to study the startup plan and conduct relevant technical briefings. ⑵ Contact the electrical and instrumentation teams to inspect the system. ⑶ Prepare fire-fighting equipment, necessary tools, lubricants, etc. ⑷ Prepare the operation record sheet and production logbook. ⑸ Fill the flotation tanks, biochemical tanks, regulation tanks, etc. with water to test for leaks. ⑹ Cultivate and acclimate the activated sludge. ⑺ Prepare the polyaluminum and polyacrylamide solutions, and get ready for water quality testing. 6.1.2 Inspection ⑴ Check whether each pool and structure is clean enough to meet the usage requirements. ⑵ Inspect all pipelines, valves, oil collection facilities, and sewers. ⑶ Inspect the mechanical equipment; once it is confirmed to be in good condition, close all vents. 6.1.3 Commencement of operation ⑴ When the liquid level in the lifting tank rises to 3 meters, start the lifting pump to supply water to the oil separator and the regulating tank. ⑵ The wastewater is introduced into the flotation tank, while the dosing system and mixer are activated to inject the polyaluminum solution into the water inlet pipe. ⑶ After the water quality of the flotation effluent meets the requirements, it is introduced into the aeration tank and the plug-flow aeration tank; simultaneously, the blower is started to supply air to the plug-flow biological tank. ⑷ Once the water meets the standards, it is pumped out using the external transfer pump for discharge. ⑸ A submersible pump in the activated sludge tank returns sludge to the plug-flow bioreactor. 6.2 Shutdown 6.2.1 Collect all the floating oil from the oil separator, and stop the lift pump after the water in the tank has been pumped out. 6.2.2 Clean the scum in the flotation tank, stop feeding water and stopping the addition of chemicals. 6.2.3 After the flotation tank is shut down, reduce the speed of the aerator; if necessary, stop the blower used for forced aeration in the biological treatment process. 6.3.4 After shutting down in winter, drain the pumps, pipelines, etc. depending on the temperature conditions. Chapter 7 Emergency Plans 7.1 Emergency Plan for Heavy Rainfall During the summer, heavy rainfalls occur frequently. To ensure safe production and prevent accidents such as water overflowing from tanks or wells, the following emergency plan for heavy rainfall has been formulated. ⑴ Closely monitor the weather conditions, adjust the levels of the lift tanks, regulating tanks, and retention tanks in a timely manner, and adjust the amount of rainwater based on the specific situation. ⑵ When heavy rainfall requires the use of two or more lift pumps, two oil separation tanks should be used, and it is necessary to first ensure that the openings for the oil collection pipes in these tanks are oriented upward. Two flotation pumps need to be operated to ensure that rainwater can be discharged without any obstruction. To reduce the retention time of rainwater, the floating cross-line can be activated, following a process that involves a primary flotation pump and a secondary flotation tank. ⑶ Rainwater pollution is low, allowing it to be discharged directly; refer to the following process. ⑷ Discharge after flotation: Open valve 8 in the north valve well of the circular aeration tank and valve 9 at the inlet of the external transfer tank; close valves 1, 2, and 3 at the inlet of the circular aeration tank as well as valve 4 in the south part of the circular aeration tank. ⑸ After circular aeration, carry out external discharge: open valve 9 at the inlet of the external transfer tank, and close valves 6 and 7 at the inlet of the aeration tank. Note: All the operations mentioned above represent changes to the normal production process. Before making any adjustments, it is necessary to check the status of all valves to avoid accidental actions. 7.2 Emergency Plan for Fire and Explosion Incidents ⑴ Immediately call the emergency number 4879119, providing details of the location, area, and type of fire, and also inform the dispatch center and the workshop. ⑵ Stay at your posts, under the unified command of the squad leader, and take emergency fire-fighting measures. ⑶ Immediately close the inlet and outlet valves of the pool and tank to prevent the fire from spreading. ⑷ Use the fire extinguishers and other equipment available at the post to extinguish incipient fires. 7.3 Emergency Plan for Oil Spill from Oil Tanks ⑴ During heating: ① Immediately close the steam valve. ② Open the two bypass valves; if necessary, close the main steam valve or release some steam through the drain valve. ⑵ During oil transfer: ① Stop the pump immediately. ② Close the oil tank inlet valve. ③ Open the two bypass valves. ④ In special cases, some oil is drained through the dehydration valve. 7.4 Emergency Plan for Total Power Outage ⑴ Immediately close the outlet valves of all pumps. ⑵ Report to the head office dispatch team and the workshop, and inquire about the cause of the power outage and the time when power will be restored. ⑶ In the event of electrical issues at this site, please contact the electrical maintenance team immediately for inspection and repair. ⑷ During winter power outages, it is necessary to clean the oil pipelines in use. If the power outage lasts for an extended period, the water contained within the relevant pipelines and containers should be drained to prevent the pipelines and valves from being damaged by freezing. ⑸ The relevant personnel stayed at their posts and coordinated the work, resuming production immediately upon receiving the call. 7.5 Emergency Plan for Total Water Cutout ⑴ Contact the head plant’s dispatch team to inquire about the reason for the water cutout and the time when water supply will resume; if the cutout is expected to last for a long time, report to the workshop and adjust the various wastewater treatment units accordingly. ⑵ If the flotation system is dosing chemicals, stop the dosing pump as soon as possible. ⑶ The relevant personnel remain at their posts, carry out coordination work, and prepare to put the various wastewater treatment units into operation once water flow is available
It’s better to send it in a package. By the way, in a refinery’s wastewater treatment plant, which areas are relatively dangerous? Accidents are very likely to occur.