Joint commissioning plan for sewage treatment plant

Chapter 6 Production Operation Methods and Requirements I. Operating Procedures for Starting and Shutting Down the Wastewater Treatment System 1. Preparation for startup: (1) Notify the departments associated with this position before starting up, so that they can make the necessary preparations. (2) Contact the instrumentation and electrical personnel to inspect the instruments and electrical equipment in this position and restore power supply, ensuring that the instruments are sensitive and accurate, and that the lighting is adequate. Inspect the pipelines and valves associated with this position to ensure that the valves are in the correct positions. (3) Check whether the valves in the deammonification tower, fans, water pumps, and dosing system are flexible and functional. (4) Prepare the acid and alkali solutions. (5) Check whether the analytical instruments and reagents are complete and valid. (6) All equipment is ready. (7) Once ready, report to the on-duty team leader. 2. Driving operations: (1) Report to the dispatcher that the preparation is complete; driving may proceed only after obtaining approval. (2) Open the raw water inlet valve of the regulating tank, and contact the gas generation unit to supply water to the sewage treatment station. (3) When the water level in the tank reaches 2.5 meters, open the outlet valve of Pump #1 and start it up. Keep the water level at around 2 meters. (4) Open the drain valve on the inlet pipe of the primary sedimentation tank; once water starts flowing from the pipe, open the inlet valves of the northern and southern primary sedimentation tanks, allowing water to flow into these tanks. (5) Once the primary sedimentation tank is filled, the water flows through the overflow weir plate into the collection tank, and then enters the primary sedimentation clear water tank via the outlet pipe. (6) When the liquid level in the sedimentation tank was 4.0 meters, the lift pump was started to maintain the level at around 3 meters. (7) Open the valve on the upper tower, and control the water flow to the upper tower based on the water level in the tank. (8) Start the alkali metering pump to keep the pH value of the water output from the mixer in the upper tower between 9.5 and 10. (9) Start the centrifugal ventilator, open the fan outlet valve, and open the air flow control valve for air entering the tower. (10) After water exits the tower, start the acid dosing pump and the phosphorus nutrient solution dosing pump to keep the pH of the water leaving the tower between 9.0 and 9.3. (11) The water exiting the tower flows by gravity, passes through a pipeline mixer to the neutralization tank, and then enters the anoxic tank and aerobic tank for biochemical treatment. (12) The wastewater after biochemical treatment is collected in a water collection tank and then sent to a secondary sedimentation tank for further sedimentation. (13) The effluent from the secondary sedimentation tank may be discharged into the outdoor pipeline network only after it passes the inspection. (14) When the effluent becomes turbid during operation, open the sludge discharge valve of the secondary sedimentation tank; the sludge in the sludge hopper at the bottom of the tank enters the return tank. (15) Start the sludge return pump in the sludge return tank; depending on the quality of the effluent, some of the sludge is returned to the anoxic tank and the aerobic tank, while another portion goes to the sludge thickening tank. (16) In the sludge thickening tank, depending on the water quality, the supernatant is discharged into the regulating tank; the siphon sludge discharge valve is opened, and the sludge is sent to the sludge storage tank in the dewatering room. (17) Based on the sludge tank level, start the lift pump to send the liquid to the mixer tank of the dewatering machine. (18) Start the agitator of the dehydrator, and at the same time start the PAM metering pump to feed chemicals into the mixing tank. (19) The sludge treated by the slurry separator is dehydrated within the filter cloth, and the resulting sludge cake is removed using a hand cart. (20) Inform the shift leader that the startup is complete, monitor and analyze various control parameters, and keep records of the startup process and the analyses conducted. 3. Shutdown procedure: (1) Upon receiving the system’s shutdown command, first stop the operation of the dosing system. (2) Close the valve on the main inlet pipe of the regulating tank until all the water in the tank is drained; then close the outlet valve of the lift pump and stop the operation of the water pump. (3) Close the outlet valve of the centrifugal ventilator to stop its operation. (4) Stop the Roots blower from operating and close its outlet valve. (5) Keep proper parking records and report to the team leader. II. Operating Procedures for Centrifugal Ventilators 1. Preparation Work (1) Before starting the centrifugal ventilator, close the outlet valve and open the two flow control valves on the air inlet pipe of the ammonia removal tower, ensuring that there are no debris near the inlet. (2) Check whether the motor insulation is qualified. (3) Check whether the oil quality of the fan is satisfactory, and ensure that the oil level is at two-thirds of the sight glass. (4) Turn the turbine 3–5 times in the direction of its rotation. (5) Once there are no other issues, preparations to supply power can begin. 2. Startup steps: (1) Press the “Start” button on the fan control box, and the fan will begin to operate. (2) After checking that the operation, noise, and vibration are normal, slowly open the outlet valve to the specified operating condition, and pay attention to whether the motor current exceeds the limit. (3) Record the pressure gauge readings on the static pressure chamber and the startup time, and report them to the on-duty shift leader. 3. Steps to stop the centrifugal ventilator: (1) Press the “Stop” button on the fan control panel to halt the operation of the fan. (2) Close the fan outlet valve. (3) Record the shutdown time and reason of the fan in the report. III. Operating Procedures for the Lift Pump 1. Preparation Work (1) Check whether the cable is damaged or broken, and verify that the seal at the cable’s entry point is in good condition; any signs of electrical leakage or poor sealing should be addressed promptly. (2) Use a 500V megohmmeter to measure the insulation resistance between the motor phases and between each phase and the ground; this value should be no less than 2 megohms. (3) Check whether the plugs and gaskets on the oil chamber are complete, and verify that the plugs have compressed the gaskets properly. (4) Check whether the impeller rotates smoothly. (5) Check whether the power supply unit is safe, reliable, and functioning properly, and verify that the ground wire in the cable is properly grounded. (6) Check whether the rotation direction of the water pump is correct; if it is not, swap two of the three phases. (7) Close the control valve on the pump outlet pipeline. 2. Startup steps: (1) After the preparation work is completed, startup can be carried out only with the approval of the team leader. (2) Press the “Start” button on the control box, and the water pump will begin to operate. (3) Gradually open the outlet valve after the pump is running at full speed. (Note: It must not be operated with the valve closed for an extended period.) (4) The outlet control valve can be adjusted according to the liquid level in the tank. (5) After normal operation, report to the team leader and keep a record. 3. Pump shutdown procedure: (1) Upon receiving the command to shut down the pump, close the pump’s outlet valve. (2) Press the “Stop” button on the control box to stop the pump from operating. (3) When the pump has not been in use for more than half a month, it should be lifted up for cleaning and placed in a dry area. (4) Regularly check the insulation resistance between motor phases and between phases and ground; this value should be no less than 2 megohms. IV. Operating Procedures for Three-leaf Roots Blowers 1. Preparations before operation (1) Remove any foreign objects from the pipes to keep them clean. (2) Check the tightness of the bolt and nut connections. (3) Open all the valves on the pipeline; otherwise, the fan will operate under overload and the machine will be damaged. (4) Add gear oil, ensuring that the oil level stays at the center of the oil gauge. (5) Check the belt tension and ensure that the pulleys are not loose. (6) Fill the bearing with lubricating grease; use a grease gun to add it until oil begins to leak out from the drain hole on the gland. (7) Turn the pulley by hand; the fan may be started only after it is confirmed to be rotating without any abnormalities. 2. Blower startup steps: (1) After the preparation is complete, press the “Start” button on the control panel to start the blower. (2) At the beginning of operation, noise and high current levels occur due to the viscosity of the lubricating oil, but these issues disappear on their own after 10–20 minutes of operation. (3) The flow rate cannot be adjusted by turning on or off valves; it is adjusted by changing the speed and adding overflow pipes. (4) The fan should operate at the specified pressure, and the motor current level must be below the rated value indicated on the nameplate; otherwise, the motor’s lifespan will be reduced. (5) Open the pressure gauge valve to measure the air pressure. (6) Once the fan is operating normally, record the start time as well as the pressure and current readings, and report them to the shift supervisor. V. Operating procedures for the sampling pump: (1) Open the suction pipe valve before starting, and close the outlet valve. (2) Press the “Start” button on the control box, and the pump will operate. (3) After the motor starts, slowly open the outlet valve; once the pump is in normal operation, adjust the outlet valve to the desired opening degree. (4) Keep proper startup records. VI. Operating Procedures for the Chemical Addition System 1. Storage of acids and bases (1) Upon receiving a notification to receive acid or base, open the inlet valve of the storage tank for that substance, open the valve connecting to the level gauge, open the vent valve at the top of the acid storage tank, and close the drain valve at the bottom; then report that the conditions for receiving acid are met. (2) Closely monitor the changes in the liquid level indicator; when the liquid level is 20 centimeters from the top, notify to stop feeding liquid. (3) Blow the infusion pipeline with air until it is completely clean; then stop the air blowing and close the inlet valve of the acid or alkali storage tank. (4) Keep proper records and report to the on-duty shift leader. 2. Operating procedures for adding acid or alkali: (1) Open the water inlet valve of the acid or alkali metering tank and fill the tank with water. (2) Open the exhaust valve at the top of the acid metering tank. (3) Once the water level reaches the specified mark, close the inlet valve. (4) Slowly open the inlet valve for the acid or alkali solution in the acid or alkali metering tank; once the liquid level in the tank reaches the specified mark, close the inlet valve for the acid or alkali solution. (5) Open the inlet valve of the metering pump, adjust the pneumatic diaphragm valve on the outlet line of the metering pump, and start the acid or alkali pump. (6) Monitor the pressure gauge reading and adjust the flow rate of the metering pump to ensure that the pH value of the water output from the mixer meets the process requirements. 3. Operating procedures for adding polyacrylamide: (1) Open the water inlet valve of the PAM dissolution tank, fill it with water to the specified level, and then close the water inlet valve. (2) Start the mixer at the top of the PAM dissolution tank, and add an appropriate amount of polyacrylamide solid into the tank for dissolution. (3) After full dissolution, open the valve connecting the dissolution tank and the solution tank, fill the lower solution tank to the specified mark, and then close the connecting valve. (4) Open the inlet valve of the metering pump and the valve on the pipeline leading to the sludge dewaterer, then start the metering pump. (5) Adjust the flow rate of the metering pump and observe the formation of flocs in the mixing tank of the sludge dewaterer. (6) Keep records of the pump startup time and the amount of solution used. 4. Operating procedures for adding phosphorus nutrient solution