Key points for operation and maintenance of commonly used sewage treatment equipment

1) Coarse and fine grid cleaning machine

(a) Maintenance management

a) Regularly remove the debris intercepted by the grid, strengthen flood season inspections, increase the frequency of decontamination, and ensure smooth water flow.

b) When the grid cleaning machine is working, monitor the operation of the equipment and immediately stop for maintenance if any faults are found.

c) When encountering large debris and floating objects in front of the grille, timely clean them up to prevent damage to the cleaning machine components.

d) After each maintenance and repair work of the cleaning machine is completed, clean the inside and outside of the grille machine in a timely manner to maintain cleanliness.

(b) Safe operation

a) After maintenance and repair of the cleaning machine, screw conveyor, and slag press, check whether the equipment meets the start-up conditions.

b) When the dirt remover, screw conveyor, and slag press are stuck by hard objects or entangled with garbage, they must be shut down for treatment.

c) Pay attention to safety and have effective supervision when repairing the dirt remover or manually cleaning the slag.

(c) Maintenance and upkeep

a) Keep the cleaning machine and its surroundings clean.

b) Clean the rear wall panels and collect fibrous waste from the slag collection port once a day with a fine grid.

c) If the transmission chain flap of the cleaning machine is found to be broken, replace it immediately.

d) The cleaning machine, screw conveyor, and slag press are regularly inspected and maintained as planned.

2) Equipment in the inlet and 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 observing whether various instrument displays are normal and stable.

② The temperature rise of the bearing shall not exceed the ambient temperature of 35 ℃, and the maximum temperature shall not exceed 75 ℃.

③ There should be no abnormal heating at the mechanical packing gland. Regularly check the working condition of the grease pump or automatic refueling device, and the packing lubricated with water should not drip into a line.

④ The submersible pump unit must not have abnormal noise or vibration.

⑤ The water level of the water collection tank should be kept normal. During maintenance, it is not allowed to use the water pump to operate the water pump below the lowest working water level to pump and discharge residual water.

b) The equipment of the lifting pump station should be kept in good condition.

c) Maintain the cleanliness and hygiene of the pump station, and arrange all tools neatly.

Timely remove blockages from the pump body, gate valve, and pipeline. Timely salvage the floating objects in the pool to prevent blockage caused by suction into the pump body.

d) The water collection tank in the pump room is generally cleaned at least once a year, and relevant equipment maintenance is carried out at the same time.

e) The management of soft starters and other auxiliary equipment can be carried out according to the content of the substation.

(b) Safe operation

a) When there is a sudden power outage in the pump room or a major accident occurs to the equipment, it should be dealt with promptly and reported to the competent department of the sewage treatment plant. It is not allowed to connect the power supply or repair the equipment without authorization.

b) When cleaning the water collection tank in the pump room, special attention should be paid to preventing poisoning, an operation plan should be formulated in advance, a work ticket for the well operation should be issued, and the corresponding regulations should be followed.

c) Maintenance and repair personnel can only leave after the water pump is turned on and running stably, and after being handed over to the operating personnel and confirmed.

d) It is strictly prohibited to start the water pump frequently, and it should not be started more than 3 times per hour.

e) Stop the pump immediately when the following situations are found during operation:

① Control signal suddenly abnormal or interrupted.

② Sudden abnormal sound and vibration.

③ The temperature of the oil chamber bearing is too high.

④ The displayed values of pressure gauges and ammeters are too high or too low.

⑤ A large amount of water leakage occurred in the pipeline and valve of the computer room.

⑥ The motor has experienced a serious malfunction.

(c) Maintenance and upkeep

a) Check, 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 of the water collection tank.

(d) Technical indicators

When backup equipment is available, the integrity rate of the working equipment reaches 100%; The comprehensive integrity rate of pump room equipment should reach over 95%.

3) Aerated sand settling tank

(a) Operation and equipment management

a) The operator adjusts the inlet valve of the sedimentation tank according to the changes in water volume to ensure that the inlet water of the sedimentation tank meets the design flow rate.

b) The sand suction pump of the sedimentation tank should be operated according to changes in water volume and should not be stopped arbitrarily.

c) The sand settling tank shall discharge sand regularly based on the amount of sand accumulation, and the height of sand accumulation shall not exceed the design height.

d) The operation of the sand suction machine shall comply with the following regulations:

① The sand suction machine should be operated at least once a day (see the sand suction machine operation regulations, attached), and the operator should monitor it outdoors on site.

② After the sand suction machine is completed, restore it to its standby state.

e) The electrical equipment on the grit chamber should be treated with moisture and corrosion resistance measures.

f) The sand settling tank should be thoroughly cleaned and maintained every 2 years of operation.

(b) Safe operation

a) Observe the water discharge condition of each sand suction pump while the sand suction machine is running.

b) After the sand suction machine is completed, it is necessary to check the sand suction machine and sand water separator once.

(c) Maintenance and upkeep

a) The limit device of the sand suction machine is adjusted once a month.

b) Keep the sand discharge pipe, drainage channel, and sand water separator unobstructed.

c) Maintain a hygienic environment around the grit chamber, slag compactor, and sand water separator.

4) Integrated biological reaction tank

(a) Equipment management

(1) Ensure the normal operation of the intake gate, adjust the opening and closing limit devices, unify the opening degree, and ensure uniform water distribution in each pool.

(2) Actively cooperate with the process control work of the Process Technology Department of the sewage treatment plant.

(3) Regularly observe whether the thruster operates normally. Check if the water spray is in good condition.

(4) During the settling time of the reaction tank, observe whether there is any leakage in the aeration pipe and aeration head. If there is a large amount of leakage, immediately report for emergency repair of the aeration pipeline. During the aeration time of the reaction tank, check the aeration amount and whether the air distribution is uniform. If there are any abnormalities, apply for and arrange maintenance of the aeration equipment according to the situation.

(5) Regularly check whether the internal reflux pump operates normally.

(6) When the winter temperature is low, all water pipes in the area should be insulated properly.

(7) Timely clean up the garbage and debris in each tank and inlet channel of the aeration tank.

(b) Safe operation

(1) When installing the aeration head component, the tightening force should be appropriate and should not be too large or too small. The two ends of the aeration pipe joint should be tightened.

(2) The submersible thruster shall not be operated without water, and the blades shall not be blocked by foreign objects.

(3) The internal circulation pump and all electric valves are strictly prohibited from frequent starting, and should not exceed 5 times per hour.

(c) Maintenance and upkeep

(1) In addition to the normal scheduled maintenance, the aeration tank should be emptied and cleaned every 3 years, and the aeration device (including the aeration head, aeration pipe, submersible thruster, internal circulation pump, and other series of equipment) should be repaired at the same time.

(2) Air gate valves, aeration equipment, air pipelines, inlet gates, submersible thrusters, internal circulation pumps, and other equipment in the reaction tank shall be regularly maintained and maintained according to the sewage treatment plant plan.

(d) Technical indicators

(1) The intact rate of various equipment in the aeration tank is greater than 95%.

(2) The mechanical efficiency of aeration equipment, internal circulation pumps, and submersible thrusters meets production requirements, and the efficiency is greater than 95%.

5) Blower room

(a) Equipment management

(1) When abnormal phenomena occur in the motor, coupling, anchor bolts, and water cooling system of the blower, immediate measures should be taken to ensure that the blower does not malfunction.

(2) The shut down blower should close the inlet and outlet valves and undergo regular maintenance.

(3) Keep the fan room clean and strictly prohibit any items.

(4) Clean the air filter of the blower in a timely manner.

(5) Replace the lubricating oil of the blower in a timely manner according to the operating hours.

(6) During the operation of the blower, equipment inspectors should pay attention to observing the temperature, oil pressure, air volume, current, voltage, inlet differential pressure, water cooling system, etc. of the blower and motor.

(b) Safe operation

(1) Cleaning the blower room and blower filter screen must be carried out while the machine is shut down, and corresponding dust prevention measures must be taken.

(2) The inspection personnel deviate from the coupling when inspecting or working in the equipment room.

(3) Regularly check whether the cooling and lubrication systems are unobstructed, and whether the temperature, pressure, and flow rate meet the requirements.

(4) When the temperature, water cooling system, oil pressure, air volume, current, voltage, and differential pressure at the air inlet of the blower and motor are found to be abnormal, especially when there are signs of cracking in the coupling elastic plate, immediately notify the operating personnel to stop the machine for further investigation.

(5) Wear earplugs when entering the blower room.

(c) Maintenance and upkeep

(1) Ventilation gallery, inspected once a month.

(2) The filter material of the total air inlet curtain filter is regularly replaced.

(3) The equipment and facilities of the oil cooler and lubrication system are regularly vacuumed, cleaned, and maintained.

(4) Regularly sample and test lubricating oil, and replace it immediately if it exceeds the standard.

6) Secondary sedimentation tank, flocculation sedimentation tank, sludge return well

(a) Equipment management

(1) Regularly check the working conditions of the equipment in the valve well to see if there is any accumulated water in the well.

(2) Check the operation of the bridge crane.

(3) Check the scraping condition of the slag scraper and whether the slag outlet is unobstructed.

(4) Check whether the siphon reflux is normal and whether the opening of the reflux valve in the reflux well is appropriate.

(5) Clean the scum on the pool surface and green moss on the outlet weir in a timely manner to maintain the cleanliness of the pool surface.

(6) Bridge crane, sludge reflux pump, sludge discharge pump, and regular maintenance of various pipeline valves.

(b) Safe operation

(1) Pay attention to prevent slipping and falling accidents when inspecting the reflux well, secondary sedimentation tank, and flocculation sedimentation tank.

(2) During the inspection process, carefully follow the safety operating procedures to ensure personal safety and prevent accidents such as gas poisoning.

(3) Any problems encountered during the inspection process should be recorded and promptly reported for resolution.

(c) Maintenance and upkeep

Electrical appliances and equipment are regularly inspected and maintained according to the equipment maintenance cycle.

7) Flocculation mixing tank, sludge storage tank, dehydration machine room

(a) Equipment management

(1) Conduct an inspection every 2 hours to check the working conditions of each equipment. During the shutdown period, check every Tuesday and Friday.

(2) If abnormal vibration, noise, odor, or excessive temperature rise of bearings and transmission components are found in the equipment, notify the operating personnel to stop the machine in a timely manner for further inspection.

(3) After each maintenance and repair work is completed, immediately clean the equipment and the site.

(4) The sludge produced during maintenance is transported to the designated location for landfill, and the discharged sewage is returned to the front pool of the inlet pump room.

(5) The discharged waste oil must be stored or utilized according to regulations and must not be discharged into sewage pipelines.

(b) Safe operation

(1) During the operation of sludge thickeners, centrifuges, and sludge transfer pumps, check the operation of the equipment at any time, and maintain and minor repair them in a timely manner.

(2) When carrying out equipment maintenance and repair work on the top of the silo, the platform of the sludge mixing tank, and the sludge transfer pump, special attention should be paid to personal safety, and guardians must be arranged.

(3) When equipment such as sludge thickeners, centrifuges, and sludge transfer pumps are shut down for maintenance due to malfunctions, warning signs must be hung on the main control power supply of the equipment to prevent misoperation and electric shock accidents. Strictly follow the operating procedures during maintenance.

(4) Strictly control the dosage during the operation of the dosing and mixing equipment. And provide personal protection such as anti slip and corrosion protection.

(5) The dosing pipeline should be regularly flushed with clean water to prevent blockage of the pipeline by chemicals.

(c) Maintenance and upkeep

(1) After the sludge feed, discharge, and dosing pumps are stopped, maintenance must be carried out once.

(2) Rinse, regularly clean, unblock or replace the nozzle and high-pressure water pipe of the filter cartridge and the water collection tank.

(3) Regularly inspect and repair the air compressor and air pressure system.

(4) Regularly inspect the sludge concentration tank.

(5) Timely lubrication of various mechanical equipment.

(6) The constant pressure variable frequency water supply system for shared water is overhauled once a quarter.

8) Sewage treatment plant equipment inspection management

Equipment patrol inspection is an important system to grasp the operation status of equipment, in order to timely detect potential equipment hazards, monitor the dynamic operation of equipment, and ensure safe operation of equipment. It is carried out seriously and according to the prescribed route. Normal patrol inspection should be conducted every 2 hours. (Night shifts generally use turning off the lights for inspection).

(a) Normal inspection

Inspection content:

1) Check if the oil level of the oil injection equipment (including the pipe sleeve and main body) is normal, the oil color should be transparent and not black, and the shell should have no leakage or oil leakage.

2) The flexible wire shall have no loose, broken, excessively tight, loose or other phenomena, and the contact and joint of the knife shall not generate heat.

3) The surface of porcelain materials such as porcelain bottles and porcelain sleeves is clean and free from any abnormal phenomena such as damage, cracks, discharge flashover, and severe corona.

4) The sound and temperature of transformers, converters, voltage transformers, reactors, etc. are normal. The explosion-proof film is intact.

5) The opening and closing indication position of the oil switch is correct. There is no abnormal sound inside the switch, and there is no oil spray on the explosion-proof tube. The operation box door and the high-voltage switchgear network door are tightly closed.

6) The lightning arrester and grounding device (including recorder) are intact and in good condition.

7) The outer shell of the power capacitor is not deformed, there is no abnormal sound inside, and all connections are in good condition.

8) There is no oil leakage or discharge in the power cable terminal box, and there is no bulging or overflow of asphalt.

9) Check whether the relay protection device operates normally at the contact position, whether the wiring terminals are burnt red or disconnected, whether the pressing plate position is consistent with the required position, and whether the indicating position of the indicator light is correct.

10) Whether the position of the relay and automatic device is consistent and whether the contact is good.

11) Check for any abnormal sounds, sparks, and burnt odors in the relay and secondary wiring.

(b) Special inspection tour

Targeted inspection

1) In addition to the equipment involved in the accident, other equipment related to its electrical or installation location should also be inspected.

2) Equipment with abnormal conditions such as overload, overheating, abnormal noise, and vibration, as well as equipment operating with serious defects.

3) Equipment that may be affected by sudden and abnormal climate changes (thunderstorms, hail, typhoons, freezing, etc.).

4) Newly put into operation equipment or equipment put into operation after major modifications.

5) Inspection before and during holidays, as well as major events.

(c) Special inspection:

1) During the severe cold season, it is important to check whether the oil level charged is too low, whether there is a false oil level, and whether the wires are securely connected.

2) During the high temperature season, it is important to check whether the oil filling surface is too high, whether the oil temperature of transformers and other components exceeds the regulations, and whether the wire joints have heating or melting phenomena. Is the cooling device working properly.

3) Before the strong wind, check and handle whether the outdoor equipment is severely loose and whether there are any abnormalities in the connection and fixation.

4) During heavy rain, check the doors, windows, roofs, and walls of the power distribution room and instrument control room for leaks, water seepage, and other conditions. Check for water leakage in each junction box.

5) After lightning strikes, check the lightning arrester, porcelain bottle, and porcelain sleeve for any signs of flashover, and check the operation of the lightning arrester.

6) In foggy days, frost seasons, and polluted areas, check the degree of pollution in the ceramic insulation of the equipment, and whether there are any abnormal phenomena such as discharge and corona in the ceramic insulation of the equipment.

7) During peak load periods, it is important to check whether the load of the outgoing line (motor) and main transformer exceeds the rated value, and to check whether the equipment has overheating caused by overload.

8) After the accident, in addition to checking the protective action and equipment according to the accident handling regulations, the equipment affected by the accident should also be inspected, such as whether the wire is burned, broken, the equipment is damaged, there is oil spray, and there is no flashover or breakage of the porcelain bottle.

9) The inspector may inspect the equipment separately, but shall not carry out other unrelated work, shall not touch the operating mechanism, and shall not open the relay cover for inspection.

(d) Integrated reaction tank effluent quality and equipment condition inspection system

Before the on duty personnel conduct inspections, they need to inquire with the office staff about the water quality of the effluent and the operating conditions of the equipment. They should focus on inspecting cells that are prone to mud leakage and faulty equipment, while other equipment should undergo routine inspections.

Inspection content:

a) Situation inside the biochemical pool:

(1) Clean up floating debris on each pool surface in a timely manner.

(2) Whether the diving thruster in the anaerobic pool and anaerobic pool pushes the water evenly.

(3) The amount of aeration in the aeration tank is appropriate. Unbiased aeration, non aeration area.

(4) Adjust to an appropriate aeration rate based on the on-site situation to ensure dissolved oxygen within the normal range.

b) Intake electric gate, air gate valve

(1) Observe whether the electric head, screw rod, gate or valve are in good condition, whether there is oil leakage in the gearbox, and whether the transfer switch is in remote automatic mode;

(2) Observe the operation status (sound, vibration, temperature, lubrication, etc.) while controlling the operation status on site; Notify emergency repair immediately when the air gate valve is not tightly closed or the inlet gate cannot be opened or closed smoothly;

(3) Observe whether the electrical circuit and grounding wire are intact, whether the protective hose and insulation layer are damaged, and promptly notify management personnel of any problems found;

c) Aerator, underwater mixer, internal circulation water pump

(1) During the aeration process of the integrated reaction tank, observe whether the aeration is uniform and determine the operation status of the aeration head;

(2) Observe the appearance and joint condition of the power cable of the underwater mixer, and secure it with steel wire rope for lifting.

(3) During the operation of the pump and thruster, observe whether the motor operates normally (sound, temperature, vibration, flow rate, etc.).

(4) Observe whether there are missing parts in the on-site control box, whether the box door is closed properly, and whether the cables, grounding wires, etc. are in good condition;

d) Pipeline (air pipe, sludge pipe, water supply pipe)

(1) Check the sealing condition of each pipeline for any leakage or damage;

(2) Observe the condition of pipeline paint and anti-corrosion layer insulation layer.

(e) Patrol system

1) The pool surface inspection work is uninterrupted, and the entire factory equipment is inspected every 2 hours. Internal coordination is carried out during meal time to take over the post;

2) Record and report all abnormal situations in a timely manner;

3) When the water quality of the biochemical pool is abnormal, investigate the responsibility of the on duty inspection personnel 4 hours ago;

5) Follow the guidance and scheduling of process scheduling personnel.

(Source | New Horizon of Water Treatment)