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Key points for operation and maintenance of commonly used wastewater treatment equipment: 1) Coarse and fine screen decontamination machines (a) Maintenance management: a) Regularly remove the debris trapped by the screens. Strengthen inspections during the flood season and increase the frequency of debris removal to ensure unobstructed water flow. b) When the grid decontaminator is in operation, monitor its functioning; in case of any malfunction, stop it immediately for maintenance. c) If large debris and floating objects are encountered in front of the grid, remove them promptly to prevent damage to the components of the dirt remover. d) After each cleaning machine maintenance and repair task is completed, clean the interior and exterior of the grid machine promptly to keep it tidy. (b) Safe operation. a) After performing maintenance and repairs on decontamination machines, screw conveyors, and sludge presses, check whether the equipment is ready for operation. b) When the dirt remover, screw conveyor, and slag press are jammed by hard objects or entangled with trash, the machine must be stopped before any handling can take place. c) When servicing the decontamination machine or manually removing screen debris, safety must be observed and there must be effective supervision. (c) Maintenance a) Keep the dirt remover and its surrounding area clean. b) The fine screen cleans the rear panel daily, and removes fibrous waste from the sludge collection outlet once. c) If any breaks or similar issues are found in the drive chain links of the dirt remover, replace them immediately. d) Decontamination machines, screw conveyors, and sludge presses are regularly maintained according to the schedule. 2) Equipment in the water inlet and water outlet areas (a) Equipment management a) It is necessary to strictly implement the inspection system and comply with the following regulations: ① Pay attention to checking whether the readings of various instruments are normal and stable. ② The temperature rise of the bearing must not exceed 35°C above the ambient temperature; the maximum temperature must not exceed 75°C. ③ There should be no abnormal heating at the mechanical packing gland. Regularly check the operation of the grease pump or automatic lubrication system; for packings lubricated with water, no droplets should form when water falls. ④ The submersible pump unit must not produce any abnormal noises or vibrations. ⑤The water level in the collection tank should be maintained at normal levels; during maintenance, pumps must not be used to operate below the lowest operating level in order to remove excess water. (b) The equipment of the lift pump station should be kept in good condition. b) Keep the pump station clean and tidy, with all tools properly arranged. Remove blockages in the pump body, gate valves, and pipelines in a timely manner. Debris floating in the pool should be removed promptly to prevent it from being sucked into the pump and causing blockages. c) The collection tank in the pump room should generally be cleaned at least once a year, along with the maintenance of related equipment. d) The management of soft starters and other auxiliary equipment can be carried out in accordance with the procedures for substations. (b) Safe operation: a) In the event of a sudden power outage in the pump room or a serious malfunction of the equipment, it is necessary to handle the situation promptly and report it to the authorities in charge of the sewage treatment plant; under no circumstances should power be reconnected or the equipment repaired without authorization. b) When cleaning the sump in the pump room, special attention must be paid to preventing poisoning; an operation plan should be prepared in advance, a work permit for working underground should be issued, and relevant regulations must be followed. c) After ensuring that the pump has started and is operating stably, maintenance and repair personnel must hand it over to the operators for confirmation before they may leave. d) Frequent starting of the water pump is strictly prohibited; it shall not be started more than 3 times per hour. f) Stop the pump immediately if any of the following conditions are observed during operation. ① The control signal suddenly becomes abnormal or is interrupted. ② Sudden abnormal noises and vibrations occurred. ③ The oil chamber bearing temperature is too high. ④ The readings on the pressure gauge and ammeter are too high or too low. ⑤ There is severe leakage from the pipelines and valves in the machine room. ⑥ The motor has suffered a serious failure. (c) Maintenance: a) Inspect, adjust, and replace the mechanical seal and lubricating oil of the water pump every six months. b) Regularly inspect the float level gauge and conversion device in the collection tank. (d) When there are spare devices available for the technical parameters, the availability rate of the working devices reaches 100% ； The overall availability rate of the equipment in the pump house should be over 95%. 3) Aeration grit chamber (a) Operation and equipment management a) The operators adjust the inlet valve of the grit chamber according to changes in water volume, to ensure that the water flow into the grit chamber meets the designed velocity. b) The sand suction pump in the grit chamber should be operated according to changes in water volume; it must not be stopped arbitrarily. c) The grit chamber should discharge sediment at regular intervals based on the amount of accumulated sediment; the height of the accumulated sediment must not exceed the designed height. d) The operation of the sand suction machine shall comply with the following regulations: ① The sand suction machine must be operated at least once a day (see the regulations for operating the sand suction machine, attached hereto), with the operator monitoring it from outside the site. ② After the sand suction machinery has completed its work, return it to the standby state. e) The electrical equipment on the grit chamber should be protected against moisture and corrosion. f) The grit chamber should be thoroughly cleaned and inspected every 2 years of operation. (b) Safe operation. a) While the sand suction machine is in operation, observe the water discharge conditions of each sand suction pump. b) After the sand suction machine has finished working, it is necessary to inspect the sand suction machine and the sand-water separator. (c) Maintenance: a) The limit devices of the sand suction machinery should be adjusted monthly. b) Keep the sand discharge pipes, drainage channels, and sand-water separators unobstructed. c) Maintain hygiene around the grit chamber, screen trash compactor, and sand-water separator. 4) Equipment management for the integrated biological reaction tanks (a) (1) Ensure the proper operation of the inlet gates; adjust the opening/closing limit devices to maintain a uniform opening degree, thereby ensuring even water distribution among all tanks. (2) Actively cooperate with the work related to process control in the Process Technology Department of the sewage treatment plant. (3) Frequently check whether the thruster is operating normally. Whether the propulsion splash is good. (4) During the settling time in the reaction tank, check whether there is any air leakage from the aeration pipes and aeration nozzles; if there is significant leakage, immediately report it to carry out emergency repairs to the aeration pipelines. During the aeration period in the reaction tank, check the volume of aeration and whether the air distribution is uniform. In case of any abnormalities, apply for maintenance of the aeration equipment as necessary. (5) Regularly check whether the internal recirculation pump is operating normally. (6) When temperatures are low in winter, ensure that all water pipes in the area are properly insulated. (7) Promptly remove trash and debris from within each aeration tank as well as from the inlet channels. (b) Safe operation: (1) When installing the aeration head assembly, apply appropriate force when tightening; it should neither be too great nor too small, and both ends of the aeration pipe connections must be tightened properly. (2) The submersible propeller must not be powered on when there is no water, and its blades must not be blocked by foreign objects. (3) Frequent starting of the internal circulation pump and all electric valves is strictly prohibited; no more than 5 starts per hour are allowed. (c) Maintenance (1) Apart from regular scheduled maintenance, the aeration tank shall be drained and cleaned once every three years; concurrently, the aeration system shall be serviced (including various components such as diffusers, aeration pipes, submersible propellers, internal circulation pumps, etc.). (2) Equipment within the reaction tank such as air dampers, aeration devices, air pipes, inlet gates, submersible propellers, and internal recirculation pumps shall be regularly maintained in accordance with the sewage treatment plant’s schedule. (d) Technical indicators: (1) The integrity rate of various equipment in the aeration tank is greater than 95%. (2) The mechanical efficiency of the aeration equipment, internal circulation pump, and submersible propeller meets the production requirements, with an efficiency greater than 95%. 5) Blower room (a) Equipment management: (1) In the event of any abnormalities in the motor, coupling, foot bolts, or water cooling system of the blower, immediate action must be taken to ensure that the blower does not fail. (2) The decommissioned blowers should have their inlet and outlet valves closed, and regular maintenance should be carried out. (3) Keep the fan room clean; no items are allowed at all. (4) Clean the blower air filter in a timely manner. (5) Replace the blower lubricant in a timely manner based on the operating hours. (6) While the blower is in operation, the equipment inspectors should pay attention to monitoring the temperature of the blower and motor, oil pressure, air volume, current, voltage, inlet differential pressure, as well as the water cooling system. (b) Safe operation (1) Cleaning the blower room and blower filters must be carried out when the machine is shut down, and appropriate dust prevention measures must be taken. (2) When inspectors are walking around or working in the equipment room, they move away from the coupling. (3) Regularly check whether the cooling and lubrication systems are unobstructed, and whether the temperature, pressure, and flow rates meet the requirements. (4) If abnormalities are detected in the temperature of the blower and motor, as well as in the water cooling system, oil pressure, air volume, current, voltage, and inlet air differential pressure, and especially if there are signs of cracks in the coupling’s elastic elements, the operators must be notified immediately to shut down the equipment for investigation. (5) Wear earplugs when entering the blower room. (c) Maintenance and upkeep (1) Ventilation ducts, to be inspected once a month. (2) The filter media of the total inlet curtain filter should be replaced regularly. (3) The oil coolers and equipment and facilities of the lubrication system should be regularly vacuumed, cleaned, and maintained. (4) Regularly take samples of the lubricating oil for testing; replace it immediately if the standards are exceeded. 6) Secondary sedimentation tank, flocculation sedimentation tank, sludge return well (a) Equipment management: (1) Regularly check the operating condition of the equipment in the valve well, as well as whether there is any water accumulation in it. (2) Check the operation of the bridge crane. (3) Check the scraping condition of the slag scraping plate and whether the slag discharge port is unobstructed. (4) Check whether the siphon backflow is normal and whether the opening degree of the backflow valve in the backflow well is appropriate. (5) Remove the scum on the surface of the pool and the moss on the water outlet weir in a timely manner to maintain cleanliness on the pool surface. (6) Regular maintenance of the bridge crane, sludge return pump, sludge discharge pump, and valves in various pipelines. (b) Safe operation: (1) When inspecting the return well, secondary sedimentation tank, and flocculation sedimentation tank, be careful to avoid slips and falls. (2) During the inspection, strictly adhere to safety operating procedures to ensure personal safety and prevent accidents such as gas poisoning. (3) In case of any issues during the inspection, records should be filled out promptly and reported for resolution. (c) Maintain electrical appliances and equipment by performing regular inspections and upkeep in accordance with their maintenance schedules. 7) Flocculation mixing tank, sludge storage tank, dewatering machine room: (a) Equipment management: (1) Inspect once every 2 hours to check the operating condition of each piece of equipment. During the downtime, check it every Tuesday and Friday. (2) If abnormal vibration, noise, odor from the equipment, or excessively high temperatures in the bearings and transmission components are detected, the operators should be notified immediately to shut down the equipment for further inspection. (3) After each maintenance task is completed, clean the equipment and the work area immediately. (4) The sludge removed during maintenance is transported to a designated site for landfilling, while the discharged wastewater is recirculated to the pre-pool in the intake pump house. (5) The waste oil discharged must be stored or utilized in accordance with regulations, and must not be discharged into sewage pipes. (b) Safe operation: (1) While the sludge thickeners, centrifuges, and sludge transfer pumps are in operation, regularly check their performance and carry out timely maintenance and minor repairs. (2) When performing equipment maintenance and repairs on the top of the silo, on the platform of the sludge mixing tank, and at the sludge transfer pump, special attention must be paid to personal safety, and supervisors must be assigned. (3) When equipment such as sludge thickeners, centrifuges, and sludge transfer pumps stops operating for maintenance due to faults, a warning sign must be placed on the main power supply of the equipment to prevent accidental operations and electric shock accidents. Strictly follow the operating procedures during maintenance. (4) During the operation of the chemical dosing and mixing equipment, the amount of chemicals added must be strictly controlled. And take proper personal protective measures such as anti-slip and anti-corrosion protection. (5) The chemical dosing pipeline should be regularly flushed with clean water to prevent the chemicals from clogging it. (c) Maintenance (1) The sludge feed and discharge pumps, as well as the chemical dosing pump, must be maintained once after they are taken out of use. (2) Flushing: The nozzles of the filter cartridge and the water collection tank should be cleaned regularly, or the nozzles and high-pressure water pipes should be replaced. (3) Regularly inspect and maintain the air compressor and air pressure system. (4) Regularly inspect the sludge thickening tank. (5) Timely lubrication of various mechanical equipment. (6) The constant-pressure variable-frequency water supply system for shared water is inspected once per quarter. Equipment inspection in wastewater treatment plants is an important system aimed at understanding the operating conditions of the equipment, so as to identify potential problems promptly and monitor its operation to ensure safe functioning. It must be carried out carefully and in accordance with the prescribed procedures. Normal inspections are carried out every 2 hours. (Night shifts usually involve inspections with the lights turned off.) (1) Contents of regular inspections: 1) Check whether the oil level in the oiling equipment (including the tube sleeves and the main body) is at the proper level; the oil should be transparent and not black in color, and there should be no leakage from the casing. 2) The flexible wire shows no signs of loose or broken strands, nor is it too tight or loose; the contacts and joints of the switch do not heat up. 3) The surfaces of ceramic materials such as porcelain insulators and porcelain covers are clean, without any abnormalities such as damage, cracks, discharge flashovers, or severe corona. 4) The sounds and temperatures of transformers, converters, voltage transformers, reactors, etc. are normal. The explosion-proof film is intact. 5) The open/closed indication position of the oil circuit breaker is correct. There are no abnormal noises inside the switch, and no oil spraying from the explosion-proof tube. The doors of the control box and the panels of the high-voltage switchgear are closed tightly. 6) Surge arresters and grounding devices (including recorders) are intact and in good condition. 7) The housing of the power capacitor shows no deformation; there are no abnormal noises inside, and all connections are in good condition. 8) There is no oil leakage or discharge in the power cable termination boxes; there is no bulging or overflow of asphalt. 9) Check whether the relay protection devices are operating normally: verify the position of contacts, whether there is any overheating or broken wires at the terminal blocks, whether the position of the pressure plates matches the required position, and whether the indicator lights show the correct status. 10) The location of the relay protection and automatic devices should be consistent, and the contacts should be in good condition. 11) Check whether there are any abnormal noises, sparks, or burnt smells in the relay and secondary wiring. (2) Special inspections are conducted targetedly to examine 1) the equipment where an accident has occurred; in addition to that equipment, other devices that are electrically or physically related to it at the installation site also need to be inspected. 2) Equipment that is operating under abnormal conditions such as overload, overheating, abnormal noises, or abnormal vibrations, as well as equipment that is functioning with serious defects. 3) Equipment affected by sudden and abnormal climate changes (thunderstorms, hail, typhoons, freezing, etc.). 4) Equipment that has been newly put into operation or equipment that has been put into operation after major modifications. 5) Inspections before and during holidays, as well as in the event of major incidents. Special inspections: 1) During cold seasons, pay special attention to checking whether the oil level in oil-filled equipment is too low, whether there is a false oil level indication, and whether the conductors are securely connected. 2) During the hot seasons, it is necessary to carefully check whether the oil level is too high, whether the oil temperature of transformers and similar equipment exceeds the specified limits, and whether there is any heating or melting at the wire connections. Is the cooling device functioning properly? 3) Before strong winds, check and address any severe looseness in outdoor equipment, as well as any abnormalities in its connections and fixings. 4) During heavy rain, check the doors, windows, roof, and walls of the power distribution room and the instrument control room for any signs of leaks or water seepage. Check all junction boxes for any water leakage. 5) After a lightning strike, check the arrester, porcelain insulators, and porcelain bushings for any signs of flashover, and examine the operation of the arrester. 6) On foggy days, during frosty seasons, and in polluted areas, check the degree of contamination on the porcelain insulating parts of the equipment, as well as for any abnormal phenomena such as discharge or corona on the porcelain insulation. 7) During peak load periods, it is necessary to carefully check whether the load on the output circuits (motors) and the main transformers exceeds their rated values, as well as to verify whether the equipment is overheating due to overload. 8) After an accident, in addition to checking the operation of protective devices and the condition of the equipment involved in the accident as required by the accident handling procedures, it is also necessary to inspect the equipment that was affected by the accident. This includes checking whether the wires are burned or have broken strands, whether the equipment is damaged, whether there is oil leakage, and whether there are any flashover or breakage issues with the insulators. 9) The inspector may inspect the equipment alone, but must not carry out any other unrelated tasks; they are not allowed to touch the operating mechanisms or open the relay covers for inspection. (3) System for monitoring the quality of water discharged from the integrated reaction tank and the operating condition of the equipment: Before conducting inspections, the personnel on duty must inquire from those who left their posts about the quality of the discharged water and the operating condition of the equipment. Special attention should be paid to cells prone to sediment buildup and faulty equipment, while routine inspections should be carried out on the other equipment. Inspection items: 1) Conditions inside the biochemical tanks: (1) Floating debris on the surface of each tank should be removed promptly. (2) Whether the water flow is uniform as propelled by submersible propellers in the anaerobic tank and anoxic tank. (3) The aeration volume in the aeration tank is appropriate. Unbiased aeration, no aeration area. (4) Adjust the aeration volume according to the on-site conditions to maintain dissolved oxygen within the normal range. 2) Inlet electric gate valve, air gate valve (1): Check whether the electric actuator, screw rod, and gate or valve are in good condition, whether there is any oil leakage from the gearbox, and whether the changeover switch is set to the remote automatic mode ； (2) When controlling its operation on-site, observe its operating conditions (sound, vibration, temperature, lubrication, etc.) ； Immediately notify the repair team if the air lock valve does not close properly or if the water inlet gate fails to open and close smoothly ； (3) Check whether the electrical circuits and grounding wires are in good condition, and whether the protective hoses and insulating covers are damaged; report any issues to the management promptly ； 3.) During the aeration process in the integrated reaction tank, observe whether the aeration is uniform and assess the operating condition of the diffusers for the aerators, submersible mixers, and internal recirculation water pumps (1) ； (2) Inspect the appearance and connectors of the power cable of the underwater agitator, as well as the securing condition of the lifting wire rope. (3) When the pump and propeller are in operation, observe whether the motor is functioning normally (sound, temperature, vibration, flow rate, etc.). (4) Check whether there are any missing parts in the on-site control box, whether the box door is properly closed, and whether the cables, grounding wires, etc. are in good condition ； 4) Pipelines (air pipes, sludge pipes, water supply pipes) (1) Check the sealing condition of each pipeline for any leaks or damage ； (2) Inspect the pipeline paint, anti-corrosion layer, and insulation layer. Inspection system: 1) Surface inspections of the pool are carried out continuously; a full inspection of all equipment in the plant is conducted every 2 hours. During meal times, arrangements are made internally to cover the duties ； 2) All abnormal situations must be recorded in a timely manner and reported promptly ； 3) When the water quality in the biochemical tank is abnormal, investigate the responsibility of the on-duty inspector from 4 hours prior ； 5) Follow the guidance and scheduling of the process dispatcher.