During the operation of the biochemical tank, once the microorganisms are impacted by the load (water quantity and concentration), the COD removal rate will suddenly drop, and in severe cases, the sludge will fall off from the biological filler and the effluent will become mixed. At this time, the water inflow should be stopped immediately, and powdered activated carbon should be added to the biochemical tank to reduce the sludge load. The dosage ratio of powdered activated carbon is1100m3 biochemical pool volume 100 kg. When the settling performance of sludge is restored, the rapid proliferation method of sludge domestication can be adopted. Domestic sewage, waste alcohol or wet paste cooked with dry flour can be added to the biochemical pool, and the addition ratio is 5-1000 kg of dry flour per1000 m3 of biochemical pool volume. After 2-3 days, water inflow began and increased day by day until the microorganisms returned to normal.
72. What if a large number of microorganisms die?
When microorganisms are seriously damaged and die in large numbers, but the rescue is ineffective, they should immediately report to the local environmental protection department for the record and replace the activated sludge immediately. Then find out the reason to prevent similar accidents from happening again. As long as it is declared in time, the wastewater discharged during sludge renewal and domestication can be treated without paying sewage fines.
73, how to ensure that power equipment always keep good working condition?
In order to achieve good treatment effect, the sewage treatment system must always keep all kinds of equipment in good working condition and maintain its due technical performance. The correct operation, maintenance and repair of equipment is the premise of the normal operation of sewage treatment system.
With the development of sewage treatment, the degree of mechanization and automation of sewage treatment system is constantly improving, and the equipment used in sewage treatment system is becoming more and more complicated. The sewage treatment system not only uses many unique sewage treatment equipment, but also uses many general equipment, which should be used, maintained and repaired well.
All these devices have their own operation, operation, maintenance and repair rules. Only when the equipment is operated and maintained correctly according to the specified working conditions and operating procedures can the equipment be in a good technical state. At the same time, in the process of long-term operation of mechanical equipment, due to friction, high temperature, humidity and various chemical effects and functions, it is inevitable to cause wear and tear of parts, maladjustment of coordination, gradual deterioration of technical status and gradual decline of operation effect. Therefore, it is necessary to disassemble and maintain the equipment accurately, timely, quickly and with high quality, so as to restore the performance of the equipment and keep it in good working condition.
74, sewage treatment system generally have what special equipment?
Special equipment: various sewage pumps, sludge pumps, storage pumps, metering pumps, screw pumps, air compressors, Roots blowers, centrifugal blowers, surface aerators, automatic water sampling prototypes, grid cleaners, sand scrapers, mud scrapers, sludge concentration scrapers, biogas digester sludge mixing equipment, biogas boilers, heat exchangers, liquid medicine mixers and sludge dehydrators.
75, sewage treatment system generally have what special electrical equipment?
Electrical equipment: AC /DC motor, variable speed motor, starting switch equipment, lighting equipment, lightning protection equipment, power transformation and distribution equipment (including cables, indoor overhead lines, disconnectors, load switches, fuses, a small amount of oil switches, voltage transformers, current transformers, power capacitors, circuit breakers, protectors, automatic devices and grounding devices, etc.). ).
76, sewage treatment system generally have what general auxiliary equipment?
General equipment: electric hoist, centrifuge, incubator, oven, refrigerator, all kinds of manual and electric gate valves, butterfly valves, gate hoists and check valves, green chemical spraying vehicles, hand-propelled and electric lawn mowers, winches, lathes, planers, milling machines, bridge cranes, transport vehicles, etc.
77, sewage treatment system generally have what instruments?
Instruments and equipment: all kinds of balances, analytical instruments commonly used in laboratories, electromagnetic flowmeters, liquid level meters, air flowmeters and dissolved oxygen meters.
78. What are the key points of equipment management of sewage treatment system?
For sewage treatment system, equipment management has the following four points:
(1) Make good use of the equipment
All kinds of equipment should have operating procedures and specify operating steps. The equipment operating procedures are mainly formulated according to the field conditions of the equipment manufacturer's instructions. Workers must operate in strict accordance with the operating procedures. Working conditions shall be recorded during the use of the equipment.
(2) Maintain the equipment.
Maintenance procedures should be formulated for all kinds of equipment. The maintenance procedures shall be formulated according to the site conditions specified in the equipment manufacturer's instructions, or put together with the operation procedures. Maintenance regulations include cleaning, adjustment, fastening, lubrication and corrosion protection. Maintenance work should also be recorded. Maintenance work can be divided into: daily maintenance-refers to patrol inspection and maintenance in operation. Regular inspection and maintenance-Stop the machine regularly for inspection and maintenance. Parking maintenance refers to the maintenance of standby units or idle equipment. Seasonal maintenance-refers to the maintenance of equipment in summer, winter and rainy season, including sun protection, cold protection, moisture prevention and cooling.
(3) repair equipment.
Establish equipment maintenance standards for major equipment, and restore technical performance through maintenance. Some equipment, to clear the boundaries of major, medium and minor repairs, division of labor to implement. The maintenance cycle of major equipment must be clearly defined and maintained regularly. I didn't think of maintenance until the damage was very serious. For daily maintenance, it is necessary to make a maintenance number of quota to reduce the maintenance cost, and make detailed records for each maintenance.
(4) Management equipment
The "management" mentioned here refers to the whole process management from equipment purchase, installation, debugging, acceptance, use, maintenance, overhaul, scrapping and updating. Including the fund management of equipment (overhaul cost, depreciation cost, etc.). ), every link must have regulations.
79, sewage treatment system equipment in good condition standard is what?
The following standards can be used as complete standards:
(1) The equipment performance is good, and the main technical performance reaches the original design or the minimum limit, which should meet the requirements of sewage treatment production process.
(2) The safety system for operation and control is complete, sensitive and reliable.
(3) Smooth operation, no abnormal vibration and noise.
(4) The insulation degree and safety protection device of electrical equipment shall comply with the electrical installation regulations.
(5) The ventilation, heat dissipation, cooling and sound insulation systems of the equipment are complete and effective, and the temperature rise is within the rated range.
(6) The equipment shall be clean inside and outside, well lubricated and free from leakage (oil leakage, air leakage, air leakage and water leakage).
(7) Operation records and complete technical data.
80. What is the maintenance cycle of sewage treatment system equipment?
After the equipment is used for a period of time, minor repairs, medium repairs or major repairs must be carried out. Some equipment manufacturers have clearly stipulated the time limit for minor repairs and major repairs. Some equipment is not clearly defined, so the maintenance period must be determined according to the complexity of the equipment, the durability of the wearing parts and the maintenance conditions of our factory. Maintenance cycle refers to the working time between two maintenance of equipment, and the maintenance cycle of some equipment in sewage treatment system is shown in table. (For reference only)
Name of equipment overhaul (hours) Planned overhaul
1 centrifugal sewage pump < < 600 rpm 40000 500
2 centrifugal sewage pump < < 800rpm 30000 500
3 centrifugal sewage pump < 1000r/min20000500
4 centrifugal sewage pump >1000r/min10000500
5 sludge pump (> 1000 rpm) 8000500
6 sludge pump (<1000rpm = 10000500)
7 gas lift pump (air lift) 8 years 1 year
8 screw pump 20000500
9 Centrifugal Fan 15000 500
10 sand scraper 10000500
1 1 roots blower 15000 500
8 1. Q: In the CAST process, the mixed liquid after sludge dehydration is directly discharged into the inlet pump house, which leads to high COD and ss in the inlet water, which affects the denitrification reaction in the selection tank (because part of the C source has been degraded in the previous sand blasting grit chamber). What should I do?
A: This is a problem that is generally ignored by sewage treatment plants at present, that is, the influence of the filtrate after sludge dehydration on biochemical treatment after it returns to the biochemical tank. Because conditioners such as PAC and PAM should be added before sludge dewatering, some of them are toxic, and sludge can flow back to biochemical reaction tank with filtrate during dewatering. There is no technical problem in treating these filtrates, only the cost. If the appropriate sludge conditioner is selected and the dosage and the amount of sludge entering the dehydrator are well controlled, the previous biochemical treatment will not be greatly affected. It is emphasized that the effect of sludge dewatering depends on the whole process management of sludge treatment process, including the management of sludge concentration tank.
Q: How to determine the "sludge age"? How to control it? Is it determined by the amount of sludge discharged or by something else?
A: Mud age, F/M, etc. It is not so much a control parameter of operation as a design parameter, but only a reference parameter in process control. In actual operation, sludge discharge is usually controlled according to MLSS value plus experience. When SVI is relatively stable, SV30 can also be used as a reference.
83. Q: Our factory uses Carroll oxidation ditch process. Sometimes the ammonia nitrogen in the effluent of the unit is higher than that in the influent, with the influent TP of about 2.5 mg/L and the effluent of only about 0.2, and the three aerators are running at full capacity. I can't find the reason. What's going on here?
A: We can only make a preliminary analysis based on the information you provided. It may be that there are more nitrogen-containing organic compounds in sewage and the reaction time is not enough. The ammoniation rate of organic nitrogen is greater than the nitrification rate of ammonia nitrogen. In addition, it may be that phosphorus is not enough, which affects the effect of removing ammonia nitrogen through assimilation.
84. Q: During the operation, there is a thick layer of sludge accumulation on the surface of the oxidation ditch, and the sludge particles with a particle size of about 1mm are yellow, which often causes a large number of floating sludge in the secondary sedimentation tank, which turns white, flocs flow out with the effluent, SV30 drops rapidly, the treatment effect is lost, and the accumulated sludge is thinned and eliminated. Repeatedly, what are the reasons and what are the control measures?
Answer: It means that sludge loses its activity and ESS increases. There are two possibilities: first, the sludge itself is oxidized; The second is sludge poisoning. Judging from the phenomenon you described, the former is more likely. The specific oxygen consumption rate, that is, the ratio of endogenous oxygen consumption rate to substrate oxygen consumption rate, can be determined and targeted measures can be taken.
85. Q: How to control paragraph A of AB method? Is it continuous reflux from a sedimentation tank to section A at the same flow rate? How much should SV30 be controlled? Is it 5%- 10%?
Answer: The reflux ratio of stage A is larger, but the sludge can't stay in a sedimentation tank for too short. Although adsorption is the main stage in A, there is also some biodegradation. Biodegradation is mainly carried out in sedimentation tanks. Only by degrading the organic matter adsorbed on the sludge surface can the adsorption capacity be restored. It should be controlled by MLSS, and SV30 can also be used when the sludge settling performance is stable, depending on the actual situation. The precipitation ratio of 5%- 10% is too low.
86. Q: If the treatment effect of a sewage plant does not reach a good state after one or two years of operation, should we consider re-cultivating bacteria (changing mud)? What's the difference between changing mud and cultivating bacteria at first?
A: No need to change! The operating conditions remain the same, so do the changes. Even if you use the dominant strain, it's useless. Only for a while. It is important to control the operating conditions. If it is a design problem, it should be rectified in time.
Q: I debug industrial wastewater. The process is hydrolysis+anaerobic+aerobic tank 1+ aerobic tank 2+ precipitation. Due to installation problems, the aeration tanks are unevenly distributed (circular aeration head aeration), and there is a similar fountain (about 1m in diameter) rolling up and down at each aerator. The uneven aeration has a great influence on the treatment effect. It is also found that there are few biofilm on the filler in the aeration area, and there are large metazoans under the microscope, and no other organisms are found. The surface of the filler biofilm is light yellow, and the biofilm outside the aeration zone is 3cm thick. Can you explain it to me?
A: You are not talking about uneven aeration, but a normal phenomenon. You said there weren't many biofilms. I wonder how many? If the biofilm basically covers the filler, it will be good. As for the biofilm outside the aeration zone, it is a serious nodulation, and measures should be taken, such as washing with the atmosphere and removing the anaerobic membrane.
Q: I would like to ask the following questions about contact with oxidation tanks.
(1) How long can the sludge on the packing survive when the contact oxidation tank is emptied?
(2) When the treatment capacity of the contact oxidation tank decreases, should nutrition be supplemented?
(3) Do you think it is effective to add kerosene to defoam the foam? If it is effective, how much is it usually added?
A: The answers to the three questions are as follows:
(1) After the contact oxidation tank is emptied, it is not a question of how long the biofilm sludge can survive, but to prevent the soft filler from drying and hardening in the sun. After hardening, it is difficult to stretch out after soaking in water, so it is necessary to prevent this from happening.
(2) The decline of the treatment capacity of contact oxidation tank should be considered from many factors, among which the thickness control of biofilm is very important, and too thick membrane will seriously affect the treatment capacity. It should also be noted that the cans can only be placed slowly when empty, otherwise the soft packing frame with a large number of biofilm will collapse or deform;
(3) It is more effective to spray chemical foam with water (it cannot be washed directly with water), and it is not in favor of defoaming with kerosene and other methods.
89. Q: The average data of water inflow, water outflow and biochemical pool in our factory in the past week are as follows: water inflow: BOD: 253 COD: 810 pH: 7.9 SS: 286 chroma: 32 times.
Ammonia nitrogen: 28 total nitrogen: 64 total phosphorus: 6.0 effluent: BOD: 4.8 cod: 74 ph: 8.1ss:12 chroma: 8 times ammonia nitrogen: 7.6 total nitrogen: 22.8 total phosphorus: 1.02 biochemical pool: mlss:
Sludge index: 1 18.9 Sludge age is 35 days.
An improved activated sludge process was adopted. At present, the inflow is only about 25,000 tons/day (designed as 50,000 tons), of which more than 80% is industrial wastewater and a small amount of landfill leachate with high concentration. The technological process is aeration grit chamber-post-biochemical tank-post-secondary sedimentation tank, non-contact tank and hydrolysis tank. The biochemical pool is supplied with air by blower and aerated by deep-water turntable. Dissolved oxygen can't reach 1mg/L when water is continuously fed, and slowly rises to about 4-5mg/L after water is stopped. Excessive inflow and structural defects lead to the overload of biochemical tank and small sludge concentration tank (180m3), and a large amount of excess sludge flows back to the inflow pump house. The problem now is that (1) suspended particles of activated sludge are often found in the secondary sedimentation tank after water inflow. Is it because precipitation time is not enough or precipitation is difficult? (2) Red worms were found in three secondary sedimentation tanks. Daphnia seems to be a good performance in treating water quality. Is it because of the high sludge concentration that a large number of people breed? (3) A thin layer of floating mud is sometimes found in the secondary sedimentation tank. Is it because of poor sludge settling performance and insufficient aeration in the biochemical pool? Or is the sludge backflow not timely? (4) The triangular weir plate of the secondary sedimentation tank is easy to grow moss or algae. Is there any way to overcome it? (5) I think that the sludge has been seriously aged, and it is necessary to control the MLSS between 3000 and 3500 or lower, increase the discharge of excess sludge and reduce the sludge age, so will the impact resistance of the biochemical tank be reduced? Will the effluent quality rise?
A: Sludge is aging, but it is not serious. Sludge age has reached 35 days. According to this calculation, the sludge load is less than 0.03. It is enough to control 2/3 of the current sludge concentration, and the sludge concentration should be gradually reduced. Daphnia has no effect on the effluent, so don't bring Daphnia when analyzing and sampling. Attention should also be paid to the mud layer control of the sedimentation tank. Moss and algae on the triangular weir plate of the secondary sedimentation tank can only be removed manually.
90. Q: We have two-stage biochemical treatment of petrochemical wastewater. The first stage is a circular fully mixed aeration tank, and the second stage is a plug-flow aeration tank. The first stage is 0.2 mg/L dissolved oxygen, and the second stage is 5.0 mg/L dissolved oxygen ... During this period, the influent pH of the primary biochemical treatment is 8.0, the effluent pH is 6.5, and the pH after the secondary biochemical treatment is 5.78, which exceeds the range of indicators 6-9. What happened?
A: It is normal to have a low level of DO, because the sludge load is high. The reason for the decrease of primary pH may be acidification caused by high load, and the decrease of secondary effluent pH may be caused by the consumption of alkalinity by nitrification reaction. Because your introduction is too simple, I can only simply analyze and infer.
9 1. Q: In order to remove ammonia nitrogen, besides having enough carbon source and a long sludge age to ensure enough reflux, is the reflux the effluent from the aerobic tank or the effluent from the bottom of the secondary sedimentation tank? I am debugging spandex wastewater now. Originally, I designed the effluent reflux of the aerobic tank, but in fact, if the reflux flow doubles, the anaerobic environment of the anoxic tank in front can not be guaranteed. My master said that it would be better to control the dissolved oxygen in the aerobic tank at around 1 mg/L, right?
A: According to your introduction, it should be pre-denitrification, and the effluent from aerobic tank and sludge from secondary sedimentation tank need to be refluxed. If you say that doubling the reflux can't ensure the anaerobic environment of the anoxic pool in front, it's wrong. The anoxic zone never tires of oxygen, so the do is less than 0.5 mg/L. It is also reasonable for your master to control the dissolved oxygen in the aerobic pool at around 1mg/L, which can prevent the DO in the anoxic zone from being greater than 0.5 mg/L. If the DO in the aerobic zone is about 1, and the effluent reflux doubles, the DO in the anoxic zone is still greater than 0.5 mg/L, and the dissolved oxygen in the aerobic zone cannot be reduced, resulting in effluent. At this time, the sludge output of the secondary sedimentation tank can be reduced, and the sludge layer in the tank can be raised to increase the residence time of sludge in the secondary sedimentation tank without affecting the sludge separation effect. The reduction of sludge output in the secondary sedimentation tank will not affect the amount of sludge flowing back to the reaction tank, because when the sludge layer in the secondary sedimentation tank rises, the concentration time of sludge in the sludge layer becomes longer. In this case, the sludge output decreases, but the sludge concentration increases. If it is a contact oxidation process, the effluent will flow back and the sludge will not flow back. I don't approve of pre-denitrification. Because of the high energy consumption of effluent reflux, large reflux requires a large reaction tank. The statement about removing nitrifying bacteria is not appropriate, but I see what you mean.