1. Q: How is the methane produced by anaerobic digestion disposed of? How can it be utilized?
A: There are many ways to utilize it, such as as fuel, power generation, etc., but the safety requirements are very high and the investment cost is also high if it is utilized, so it is generally burned and discharged both at home and abroad, such as the methane produced by anaerobic treatment devices such as AF, IC, and so on, which are automatically ignited and burned by torches. It can also be used for biogas blower, which is a very good way to utilize, this kind of blower can be powered by electricity and biogas respectively.
2. Q: This process uses submerged biofilm. Considering the additional carbon source to increase the amount of labor, it is also not economical to reduce dissolved oxygen, ammonia and nitrogen effect removal is also okay, the effluent nitrate 11mg / L, but nitrite is very high. Please advise: Can the nitrogen removal effect be improved in the case of low C/N?
A: short-course denitrification can be used, because short-course denitrification is directly nitrite nitrogen denitrification to nitrogen, can greatly save energy, just because nitrite nitrogen is unstable, it is difficult to accumulate, since the effluent nitrite nitrogen is so high, why not try it? If it can be realized, to add a carbon source is also very cost-effective.
Q: pig wastewater, influent: COD1500, ammonia nitrogen 500, TP60, alkalinity 3000, nitrate nitrogen and nitrite nitrogen instrument can not be detected, certainly a very low value. Effluent: ammonia nitrogen 120, COD700, but nitrate nitrogen up to 1200, nitrite nitrogen 250. SRT: 1 day is this situation normal? Where does such high nitrate nitrogen come from? How to explain?
A: If the data measured correctly, there is only one explanation, that is, the total nitrogen is much higher than the ammonia nitrogen, nitrogenous organic matter constantly ammonia, ammonia nitrogen nitrification, and at this time the treatment system is in aerobic conditions, nitrate nitrogen can not denitrify and a large number of accumulations, in this case, if the treatment time increases, the effluent ammonia nitrogen can be reduced, the effluent nitrate nitrogen will increase.
Q: I debug a food wastewater, UASB produces granular sludge before the raw water COD2000-3000, the effluent has been 750 or so. This period of time is about 50 days. During this time run a small amount of flocculent sludge. After that, the concentration of wastewater reached 4000-5000, reduced the amount of treated water, has been to keep the water less than 1000. after that, began to increase the amount of treatment. After that, the treatment volume started to increase, and the flocculation became more serious, the mud production was very large, and the three-phase separator was not good. When I reached half of the designed treatment capacity, the company asked me to increase the water volume quickly because the aerobic is bigger. In the process of speeding up the water quantity, the gas production was decreasing, and the water output was 1100-1500. it was close to the design flow rate after fifteen days, but the cooperation with Party A was not good, and we failed to take samples for acceptance. After that, Party A’s production decreased, but the water quality concentration changes 3000-5500, after adjusting the flow rate, gas production began to increase slightly, but the particles of sludge with the water out of a large number of non-bubbles out of the main, even if the water is not into the water, there will be a large number of sludge floating up, never sinking. This phenomenon has been more than ten days.
A: It may be that the load is too large, which prolongs the acidic fermentation process and causes the alkaline fermentation process to be incomplete. For the feed load is not stable treatment device, the best pre-acidification of sewage before entering the UASB device, so as to improve the pH, better guarantee the treatment effect.
5. Q: I am doing the UASB anaerobic biochemical treatment experiment of molasses alcohol waste liquid, at present, the influent concentration is 30000~50000mg/L, the removal rate is 55~60%, the load is 20KG, in which we meet a lot of difficulties, mainly the influence of sulfate, the loss of the inoculated sludge (non-granular sludge) is serious, and the biochemical properties are poor. I think the reason is mainly caused by the bad acidification stage, I wonder if it is so?
A: Two comments for reference: (1) acidification time should not be long, so as not to affect the subsequent biochemical treatment of pH is too low; (2) the cultivation of granular sludge, you can add appropriate amount of activated carbon or PAM in the inoculated sludge, which is conducive to the formation of granular sludge. Because we do not know the specific situation is for reference only.

6. Q: denitrifying polyphosphorus bacteria (DPB) simultaneous phosphorus removal and denitrogenation process operation and management of what matters to pay attention to?
A: Operation and management requirements of many, such as anaerobic tanks can not have oxygen, but how to control it? Aerobic zone oxygen will affect the nitrification and polyphosphorus, oxygen is too high will make the anaerobic zone micro-oxygen environment, affecting the release of phosphorus, sometimes aerobic zone dissolved oxygen is not high, anaerobic zone may also have micro-oxygen, this is the dissolved oxygen with the aerobic zone outside the high and low, but also with the dirt sedimentation tank residence time, anoxic degree and other factors. In addition, it is also necessary to do according to the process requirements of timely sludge discharge, phosphorus is the ultimate way to remove the remaining sludge discharge, such as timely discharge, will be in the system week after week to carry out the cycle of polyphosphorus and phosphorus release.
7. Q: I have a business side of the treated sewage is ready for reuse, the treatment process is: conditioning tank – anaerobic tank – aerobic tank – a sinking tank – air flotation tank – outfall, which is added to a sinking tank of ferrous sulfate and lime, air flotation tank to add aluminum chloride and polyacrylamide, the water quality of the iron ions is very high, I do not know if there is any good way to reduce its content, the cost of course, can not be too high?
A: Do not use air flotation, can be aerobically treated water with lime, adjusted to pH 8 or so, and then add PAM, and control the mixing and other flocculation conditions, which can improve the removal rate of iron ions, you can try.
Q: BOD and COD in the relationship between COD is greater than BOD, COD – BOD is equal to non-biochemical organic matter
A: This is not accurate, because COD = COD (B) + COD (NB), the former is the part of the biochemical, the latter is not biochemical part. And microorganisms in the case of 20 degrees to complete the carbonization process takes about 20 days (that is, BOD20 and CODB close).
9. Q: a county, about 200,000 people, pre-built a municipal wastewater treatment plant, the size of 20,000 tons / day, due to limited government funds, construction costs want to control the 15 million or so, which process is more appropriate?
A: It is recommended to use nanometer diatom fine soil method, this method is especially suitable for urban wastewater treatment, the sludge can be used as thermal insulation materials, less investment, operating costs are only half of the traditional method. The difference between nano diatomaceous earth and general diatomaceous earth is that it has strong electric neutralization effect through special treatment, and the specific surface area is greatly increased.
Q: The sewage treatment plant is pulp and paper wastewater treatment, the use of complete mixing method, the sludge has recently appeared in the phenomenon of SV down to 5-6, the sludge is only bellworms, rotifers, the treatment effect is general. Recently, the F/M is around 0.3, the temperature is high, and the temperature of the aeration tank is 37-39 degrees, is it sludge poisoning? Or other reasons?
A: F/M is not too low, it doesn’t look like poisoning from the biological phase, because the bellworms are very sensitive to toxic substances. It may be due to high water temperature. Generally speaking, water temperature over 38 degrees will have some effect on the activity of aerobic microorganisms.
11. Q: I am now debugging SBR, treatment of slaughterhouse wastewater, the supernatant after sedimentation in the past few days there are always fine particles of mud suspended, can not be precipitated, resulting in the effluent COD, SS can not meet the standard, the water temperature is about 35-37 degrees, is the temperature is too high to lead to? What should be done?
A: The sludge has signs of aging, the temperature of the microbial activity of some impact, but not the main reason, mainly because of the aeration time is too long, to reduce the aeration time (such as intermittent aeration), but also need to drain the mud. Reduce the aeration time is to reduce the time of the reaction stage, due to a running cycle time is fixed, the idle stage time can be increased accordingly, the intake stage, such as the use of unrestricted aeration, then changed to restricted aeration.
Q: Acrylonitrile-containing wastewater, plus PAC and PAM, and then biochemical, ammonia nitrogen content of up to 217mg / L. Analysis may be acrylonitrile converted to acrylic acid and then converted to ammonia nitrogen, may amide also increase ammonia nitrogen, there is no theoretical and experimental data based on, is it possible to explain?
A: This situation is very normal, is the cause of ammonia, this kind of wastewater needs a long time to deal with, the effluent ammonia nitrogen is so high that acrylonitrile ammonia process has not been completed, to make the ammonia nitrogen to meet the standard, but also need to increase the biochemical reaction time.
13. Q: How to return the sludge from three oxidation ditches and two secondary sedimentation tanks? Two two sedimentation tanks set up a sludge pump room, how can the return sludge evenly distributed to the three oxidation ditch?
A: The sludge pump is set up before the mud pool, reflux sludge is lifted by the pump through a reflux sludge pipe to the oxidation ditch, and then divided into three branch pipes into the oxidation ditch.
Q: Existing high concentration of wastewater (BOD value of about 6000), please ask: activated sludge treatment (SBR method) to meet the requirements of sludge loading MLSS value to take a very large value (such as 20,000) is not appropriate? What kind of problems will occur? What is a better way to avoid the problem?
A: Such a high concentration should not be treated directly by aerobic treatment, but should be treated anaerobically before aerobic treatment. Regardless of the SBR method or other activated sludge methods, the MLSS should be controlled according to the F/M value and is limited by factors such as settling time and oxygen supply capacity.
15. Q: I am doing aquatic processing wastewater program with UASB, the water quality is as follows: Q=200t/d, COD=3000, BOD=1000, SS=300, Total Nitrogen=200, Ammonia Nitrogen=20. wastewater discharge standard: effluent requirements COD<300, BOD<150, SS<200, Total Nitrogen<40, Ammonia Nitrogen<25.
Please advise the following water quality conditions: (1) Is it possible to remove the total nitrogen without lowering the BOD after BOD<150 in order to save the project investment? (2) Is the end point of reaction for nitrogen in UASB NH4+ and NH3?
A: The transformation of nitrogen in UASB is mainly the ammonification of organic nitrogen, so it is necessary to continue ammonification, nitrification and denitrification after UASB, and it is recommended to use A2/0 contact oxidation method after UASB.

16. Q: Pig wastewater COD: 10000, ammonia nitrogen 400, anaerobic + SBR effluent COD: 150, ammonia nitrogen 150, 300 square meters / day, stabilization pond 15 acres, can be stored 1-1.5 meters deep, how to design the stabilization pond, early June planting of any plants, whether the water can be up to a level?
A: Two stabilization ponds can be used, the first level of aeration ponds, the second level of static ponds. Aeration ponds can be installed a small number of floating aerators (the same as fish ponds), generally not often aeration, static ponds can be propagated water hyacinth and other aquatic plants.
Q: I am now experimenting with a chemical wastewater treatment, the main processing difficulties are: poor biochemistry; easy discoloration (more serious than the degree of discoloration of dye wastewater); and the wastewater has a strong corrosive, its PH value of about 2 or so; biochemical COD is high and low, the main pollutants are also substances with benzene ring. What kind of process should be used?
A: Pre-treatment and then biochemical treatment, pretreatment can be electrolysis, fast ion removal method or acidification method.
Q: The plant is a large urban wastewater treatment plant, the daily treatment scale of 300,000 tons, the use of modified oxidation ditch process, the recent secondary sedimentation tank is particularly easy to run mud, while the oxidation ditch MLSS has been stable in the 4,000-5,000mg / L, why is this?
A: It may be the sludge itself oxidation caused by part of the sludge deflocculation caused, such as this, should increase the amount of sludge discharge, reduce the amount of aeration.
Q: There is a sewage plant, the use of ordinary aeration tanks, perforated pipe aeration, sewage has exceeded the design volume of water, the need to improve treatment capacity. Please teach in the aeration pool without changing the volume of the premise, what measures can be taken to improve the aeration pool capacity?
A: The following measures for reference: (1) set up fiber packing in the pool, using biological contact oxidation method; (2) the perforated pipe will be changed to microporous aeration hose, oxygen utilization can be increased by several times. This aeration pool volume load can be increased by more than double.
20. Q: The sludge in the aeration tank is getting less and less, the influent COD is about 100~200mg/L, sludge is difficult to grow, not put into use in the pool of dead mud, how to do good?
A: Intermittent aeration method can be used, the appropriate amount of some sludge, although the amount of sludge is very small, such as not discharging mud will be less.
21. Q: contact oxidation method of wastewater treatment, the requirements of the influent BOD can not be too high, hydrolysis and acidification and then contact oxidation can ensure that the contact oxidation pool of influent BOD requirements? If not, what should be done?
A: Hydrolytic acidification to remove COD is very limited, mainly to improve the biochemistry of wastewater, such as contact oxidation tank influent BOD is too high, anaerobic process or other methods of pre-treatment can be used.
22. Q: How to determine the amount of microorganisms in the contact oxidation aeration tank? The traditional activated sludge method can be expressed in terms of sludge concentration (MLSS), which can be visualized in terms of sludge settlement ratio (SV30). How should the amount of microorganisms in the contact oxidation aeration tank be visualized? Some people say that the thickness of the biofilm should be observed, what is the standard for the thickness?
A: The amount of biofilm in the contact oxidation tank is impossible and unnecessary to measure, the membrane on the packing is too thick, the specific surface area is small, the amount of active biofilm per unit volume is small, the membrane is too small and not good. In actual operation to control the thickness of the biological is one of the keys to operational management, the membrane is too thick to increase the amount of gas or flushing. As the biofilm are installed in the pool under the water surface, so it is best to press the installation of the pool side can be taken up to the observation of the filler, biofilm thickness to just cover the filler for the best.
Q: Some of the A/O process, A section for the anaerobic section, why also air tube aeration?
A: The use of air tube aeration, both anaerobic operation, can also be anoxic or aerobic operation, at the same time can be used in the mixing effect is not good when the aeration pipe to assist in the mixing, to prevent sludge settling, although the A section should be anoxic, but the appropriate amount of aeration (DO <0.5mg / L) is not a problem.
24. Q: In the anaerobic + aerobic process, such as anaerobic treatment also contains a large amount of sulfur, how can it be removed?
A: If there is still a lot of hydrogen sulfide after anaerobic treatment, it means that the anaerobic reaction is not complete, and the reaction conditions should be controlled.
25. Q: We design the second sedimentation tank is the sedimentation tank after Aubert oxidation ditch, oxidation ditch reflux sludge concentration requirements 8g / L, afraid of the reflux sludge concentration in the middle of the week into the week out of the concentration can not be reached, so the experts recommend the use of the week into the week out, the production plant introduces this process with a single pipe suction sludge machine, the reflux sludge concentration can be reached 8-12g / L, is it right?
A: It should be used with caution, the device with poor sludge settling performance is even more inappropriate to use the circumferential sedimentation tank, and the single pipe sludge suction machine is even more unsuitable.

Q: I do 100 tons of pilot projects, the recent ammonia nitrogen removal effect is not good, the current observation of the situation: oxygen supply should be okay, alkalinity is sufficient, the biological activity is still good and no obvious toxicity, sewage boring aeration or not, can we think that the load is not a problem? Ammoniation and nitrification of organic nitrogen, is not simultaneous, of which ammoniation is slightly ahead of nitrification? Are there any other factors affecting nitrification?
A: The ammonification process of nitrogenous organic matter precedes the nitrification process and is slower than the carbonization process of organic matter, but faster than the nitrification process of ammonia and nitrogen. Nitrification can only occur at low organic loads. Although it can not be said that the completion of the ammonia process to start the nitrification process, but can be considered in the nitrification process will occur before the ammonia process, in a certain period of time the two processes will coexist. Some devices into the water ammonia nitrogen is very low, the total nitrogen is very high, after biochemical treatment, the ammonia nitrogen effluent is higher than the influent, indicating that the device not only does not have enough nitrification reaction time, and even the ammonia process is not necessarily complete. Environmental protection bee from what you say the load should be no problem, but also to confirm that the nutrient ratio is satisfied, such as: whether the phosphorus is missing, etc..
Q: We are doing a fruit juice wastewater treatment, using UASB + contact oxidation process. COD in about 8000, BOD in about 4000, pH fluctuations in 9-13 or so, sometimes there will be 5 or so of the pH, the amount of water 1200, the amount of water is unstable, debugging to pay attention to those situations?
A: This type of water quality and quantity of water regulation is very important, regulating pool capacity should be large enough to make the treatment device stable operation.
28. Q: refinery (liquefied petroleum gas, straight-run diesel fuel, catalytic cracking gasoline) alkali washing waste lye, water volume of about 4KL / HR, COD about 40,000, with what method of pretreatment?
A: Pre-treatment recommendations: because the lye inevitably contains some oil, to set up a waste lye with oil decanting function of regulating storage tanks, and then neutralize the waste lye. General waste lye also contains a high concentration of sulfide, air or other oxidation method can be used to deal with (in front of the neutralization process).
29. A couple of questions: How does the waste lye conditioning tank with oil decanting function operate? Is it separated by gravity? If emulsification is serious how to do? Wastewater cooling tower recently due to tower pipe clogging, open bypass after the water temperature can be as high as 44.7, although the reaction rate can be accelerated, but also close to the top limit of the medium-temperature microorganisms, (THH is set at 45C) had no choice but to cut the highest temperature tributary in the influent pipeline out of the system; activated sludge method of the methanol content of influent water have any limitations? Because there is a problem with the methanol tanks need to be cleaned up, and worried about the impact on the biochemical discharge field. Checked some information, some say it is extremely high biochemical, some say too high will be toxic, I do not know the right?
A: Three questions are answered as follows: (1) Strictly speaking, waste lye such as oil should be washed with gasoline first, lye tanks should also have the function of oil decanting, a simple way is to set up different heights of the tank between the upper and middle oil drain, and install valves so that you can decant the oil at different liquid levels. (2) The temperature will seriously affect the biochemical treatment effect (unless anaerobic), to have cooling measures. (3) methanol although good biochemical, but the concentration is too high, unless it is anaerobic.
30. Q: Our plant is a modified SBR, the so-called improved is the realization of a continuous water intake, just the reaction pool with a retaining wall is divided into two steps, a so-called pre-reaction area and the main reaction pool, the lower part of the retaining wall there is a 2 square meters of the cavity is connected to the sludge, there is no sludge reflux, the pre-reaction area and the main reaction pool is exactly the same, the pre-reaction area of 3.5 meters long, the main reactor pool is 36 meters long, the depth of the pool is 4.7 meters, the width of the pool 12.5 meters, decanting height of 1.3 meters, the feed water is mainly domestic sewage COD400BOD180 total nitrogen 80 total phosphorus 8, 10,000 cubic meters of water per day, and now the two reactors are running! Please teach the sludge concentration control in how much suitable? The use of aeration hose aeration, may be the aeration tube is not very good, the reaction pool is just the two ends of the aeration in the middle is not aeration! Run half a year, the water is not up to standard, COD total in about 80, sludge concentration in about 6000. Four hours a cycle, two hours aeration, 1 hour static precipitation, 1 hour decanting! Please expert guidance! The dissolved oxygen during aeration is 2!
A: According to you it should be ICEAS process. Suggest that you check whether the aeration hose before the gas bag installed in the pipeline, the pipeline system is set whether the exhaust pipe (also known as sewage pipe), because these are related to what you said the aeration pipe two ends of the gas in the middle of the air is not the case. As for the MLSS high this is only one aspect of the reason, there are aeration time and other factors.
31. Q: I am now debugging a slaughtering wastewater, process: septic tank (HRT> 2d) – regulator – hydrolysis tank (HRT = 5) – contact oxidation tank (HRT = 6) – secondary sedimentation tank, due to the former septic tank effluent COD in 700, and the contact oxidation time is relatively short, it will be changed to the water contact tank aeration tank, but the added The effect of a submersible aerator is limited DO generally below 0.5, the original aeration pool DO normal. SV of the two pools can reach 20-30, now the water intake for the design of 70% of the water, the effluent water quality is still very poor, SS is more, the original aeration pool has a certain foam, and thicker, is it because of sludge aging reasons?
A: aerobic influent COD700 is very normal, foam has nothing to do with ammonia nitrogen, to determine whether it is a biological foam or chemical foam? If it is chemical foam, it will be reduced gradually if it is maintained under such sludge concentration, and if it is not possible, it can be defoamed by spraying with water. I feel that your sludge activity is very poor, the reason may be that the nutrient ratio is not controlled properly, such as nitrogen and phosphorus.
Q: we have a project has been running for a year, recently due to the deterioration of water quality into the biochemical device S content of about 100, now the water S in about 10, the recovery of five days, the COD of the water in 600, the water 300 or so, 10×16 microscope to see some dendritic things and some very small (needle point size) things, do not know what, sludge concentration almost No, what should be adjusted now, is the sludge oxidized, the gas volume should be adjusted smaller?
A: It means that the sludge has been severely damaged and disintegrated, and has to be re-cultured.
33. Q: sewage treatment system has just been built, ready to start operation, process: regulating tank – hydrolysis tank – anaerobic tank – aerobic tank – sedimentation tank – sludge treatment system, will soon start trial operation, the proposed use of inoculation taming, what are the specific precautions to be taken in driving and taming?
A: Static cultivation should be used in the early stage of bacterial cultivation, and after the initial formation of sludge, care should be taken to prevent the sludge from over-oxidizing itself. There are a lot of factories have happened this kind of situation, the sludge does not increase for a long time, or even decline, the reason is that the nutrition and aeration time is not controlled well, the sludge in the growth at the same time and constantly oxidize itself in such a vicious circle process. Activated sludge cultivation of bacteria in the late stage, although the sludge concentration is low, or should be properly discharged some sludge, will be conducive to the further growth and reproduction of microorganisms.
Q: The unit of anaerobic treatment device will begin to debug, please say anaerobic sludge culture methods and debugging process of attention.
A: There are various anaerobic sludge cultivation methods, and it is recommended to adopt the step-by-step cultivation method, and the general process is as follows: the residual sludge (which has been anaerobically) of the aerobic system through the thickening tank is put into the anaerobic reactor, and the dosage is about 20~30% of the capacity of the reactor, and then it is heated (if it is to be heated), and the temperature is gradually increased, so that the temperature rise is 1℃ per hour, and when the temperature rises to the temperature required for digestion (according to the design temperature)), the temperature is maintained. . The amount of nutrients should be increased gradually as the amount of microorganisms increases and should not be rushed. When the organic matter is hydrolyzed and liquefied (it takes one or two months), and the sludge matures and produces biogas, analyze the biogas composition and conduct ignition test when normal, then use the biogas and put it into daily operation. The initial start-up generally controls a low organic load. Only when the CODcr removal rate reaches 80% can the organic load be gradually increased. The concentration of acetic acid to complete the startup should be controlled below 1000mg/L. The above is only a general requirement, it is best to ask experienced people to guide.
Q: I plant is an oil refinery, sewage treatment process is currently this: high concentration of sewage into the aeration biofilter treatment, a part of the low concentration of sewage treatment system into the contact oxidation tank, part of the dilution of water as a SBR (SBR treatment of alkali residue after wet oxidation), SBR treatment is completed into the contact oxidation tank of low concentration of wastewater treatment system, low concentration of wastewater treatment system for the oil, air flotation, contact oxidation tank, secondary sedimentation tank, sand, water, water, water, water, water, water, water, water, water and water. The low concentration wastewater treatment system is grease trap, air flotation, contact oxidation tank, secondary sedimentation tank, sand filter and reuse. There is a problem that the ammonia nitrogen of the high concentration wastewater before entering the aeration biofilter is always higher than that of the water out of the aeration filter. What is the reason for this?
A: It is normal, because part of ammonia nitrogen is removed in the biofilter, not by heterogeneous pathway, but by assimilation process, i.e., through bacterial synthesis.

36. Q: I would like to consult the removal rate of the problem of domestic wastewater-based sewage treatment plant, if the influent BOD/COD is 0.4 to 0.5, the effluent BOD/COD is possible to reach 0.8 to 0.9, that is, the effluent COD is 40 to 50, but the BOD can not meet the standard, why is this the case, and how to adjust the process (treatment process SBR or oxidation) How to adjust the process (treatment process for SBR or oxidation ditch)?
A: This is counterintuitive, to confirm that the BOD5 determination of whether there is a problem, such as: the determination of whether to do a blank control; sampling of fine flocs in the effluent water can not be taken into, and so on.
37. Q: Our cesspool depth of 9 meters, pool length of 50 meters wide 15 meters, the bottom of the pool is now more silt, how to remove? Pool perennial water.
A: To say clearly what process? What is the pool? Estimated that the regulator pool, the regulator pool should be configured with mixing equipment, homogenization of sewage, if not have to empty the mud.
38 Q: municipal wastewater secondary effluent if only after filtration direct utilization, filtration should be how, how to filter out particles, hair, and algae and other impurities ah? Please advise you
A: Depends on the requirements of the reuse of water, such as as general miscellaneous water, at least after coagulation, filtration and sterilization of the three processes, filtering methods, more cost-effective is to use the quartz sand filtration, as for the water, such as hair and other substances in the water should be in the front of the sewage treatment device to remove.
Q: I use anaerobic process is UASB, no heating device, the whole process does not have a sludge return system, wastewater is overflowed through the UASB to the aerobic tank, and aerobic tank is used in the biofilm method, and now we have to carry out the sludge culture, the cultivation process, what should I pay attention to?
A: UASB sludge culture can be used to transplant anaerobic sludge from other wastewater plants after thickening for cultivation, the amount of sludge should be more than 1/3 of the height of the anaerobic reaction device, and the sludge layer should be at least 1m or more. If there is no anaerobic sludge, can also be used after a period of time after the placement of aerobic sludge to transplant culture, because the culture of the initial period do not have to pursue strict anaerobic, even if the transplantation of the sludge in the oxygen will soon be depleted, and the formation of anaerobic conditions, only the culture time will be a little longer. In the process of culture, pH must be measured frequently, controlled at about 7, but also to control the nutrition. Specific culture requirements can be referred to the relevant information.
Q: We are dealing with semiconductor wastewater (containing fluoride, ammonia, phosphate). Due to the original design is not well thought out, now changed to only an aerobic tank, no anaerobic tank. Aerobic tank influent ammonia nitrogen 30mg / L or so (flow rate of an average of 30t / h), plus sodium carbonate to adjust the pH and alkalinity, pH is generally about 7.5, 24-hour aeration; in the follow-up sedimentation tank bottom put a 5t / h sludge pump, is also a 24-hour reflux, due to the bad control so that reflux sometimes sludge is sometimes sewage, the effluent ammonia nitrogen is almost 0, continuous stable operation of this for 2 months. The ammonia nitrogen in the effluent is almost 0, and the pump has been running stably for 2 months. Can it still run stably like this?
A: There are two unreasonable aspects: one is no phosphorus removal function, anaerobic should not be canceled; the second is that the amount of return sludge should be relatively stable, in the bottom of the pool with a pump so that the discharge can not be. From the reaction time of the aerobic pool and the concentration of ammonia nitrogen in the influent water, ammonia nitrogen removal should not be a problem.
41. Q: The unit is used in front of the Aubert oxidation ditch process, the recent problems in the operation. Design water intake 50,000 tons / day, COD350, BOD150, ss220, the actual water intake of 5,000m3 / d per day, COD300, BOD120, SS180; operation is inside and outside the ditch four propellers fully open, inside and outside the ditch dissolved oxygen control at 3mg / L (recent laboratory test dissolved oxygen and online instrumentation data is not the same, the instrumentation is higher than the laboratory data 3mg / L, running for two months before the laboratory to control the dissolved oxygen in the 3mg / L). L, running two months before the laboratory started.) Intermittent aeration, aeration for 5 hours, static precipitation for 1 hour (propellers all closed), water intake for 1.5 hours, water intake for one minute to open the propellers, start aeration, by the oxidation ditch in the sludge concentration of 100 or so, a reflux pump for long-term reflux of sludge, flow rate of 700m3 / h, reflux sludge concentration of 100 or so, the concentration of sludge in the oxidation ditch has been unchanged to stay at 200 or so, the effluent COD140 It is better to be around 100, BOD50, SS50, and the effluent from the secondary sedimentation tank is turbid. (1) the second sedimentation tank sludge does not settle, the whole surface of the tank is very turbid, (2) oxidation ditch sludge has no flocculating body, all are very fine particles. (3) The microscopic examination only found a kind of microorganisms, looks like bean seeds, there are bubbles in the middle, more head. (4) The oxidation ditch has been there white sticky foam, (5) we treat all domestic sewage, running 3 months sludge concentration can not come up, the water has been bad. Please help to analyze the cause of such a situation.
A: It means that the sludge has been seriously aged and disintegrated, which is caused by too low sludge loading and too long aeration time, and the sludge is growing while oxidizing itself during the cultivation process, and of course the sludge concentration will not be increased. The sludge has to be re-cultured, but the problem is that if the water intake and sewage concentration are not yet increased, how can the cultured sludge be kept? Your current operation is not working, high dissolved oxygen is not the main reason, the key is the control of aeration time. The use of intermittent aeration underwater propellers do not have to stop, the inner ditch does not have to be aeration, can be used as a mixture of liquid flow to the sedimentation tank of the aisle, but the propeller can not stop.
42. Q: for the peripheral water inlet peripheral outlet of the two sedimentation tank, its has overcome the center of the water inlet peripheral outlet of the two sedimentation tank shortcomings? Also, I found that the auxiliary flow type dessicant tanks here have the phenomenon of very small sludge flocs turning over on the liquid surface, what is the reason for this?
A: I think that the peripheral inlet type sedimentation tank only reduces the influence of inlet water energy on sedimentation and the problem of short flow of the center mixture, and does not change the problems of the amplitude flow type sedimentation tank comprehensively. Theoretically, the peripheral sedimentation efficiency should be very high, can be very high requirements for the influent water distribution.
Q: Often see in some forums like this statement “aeration is too large, DO is too high, bacteria oxidize themselves, the load is too low, the microorganisms oxidize themselves, leading to deflocculation” clouds. In ASM1#, ASM2#, ASM3# model and wastewater biological treatment of the great McCarty is the microbial attenuation coefficient as a constant, with b, that is, the attenuation (self-oxidation) is a certain ratio b at any time in the occurrence of, carried out. The growth coefficient of microorganisms is closely related to the substrate concentration, is a variable, when the organic load is low, and the supply of oxygen is sufficient, the microorganisms will quickly consume the BOD in the water, so that the growth stops, only the attenuation, which leads to a net increase of 0, or even negative, so that the biomass does not increase, but rather decline. Therefore, it is said that auto-oxidation occurs at any time, not only under low load and high DO, I don’t know if this is appropriate?
A: Theoretically it is correct, but the actual operation of sludge aging is not limited to such an understanding, although sludge aging is mainly caused by the lack of nutrients for a long time microorganisms, that is, the imbalance between the nutrients and the amount of microorganisms, microorganisms can not grow normally, but the treatment device in the actual operation of the situation is more complex, the activity of the sludge is also related to the operation of the control conditions, the nutrient ratio and other factors. Some installations will occur as follows: when the influent concentration is normal, and the carbon and nitrogen ratio or carbon and phosphorus ratio is low, the activity of sludge will also be very poor, so that the microbial degradation of organic matter is limited, and the energy produced is reduced; when the influent concentration and nutrient ratio and so on is normal, but due to the residual sludge is not discharged in accordance with the requirements, coupled with the aeration time is too long and so on will also make the sludge loose, activity is poor, and such a sludge customarily also known as aging.

44.Q: There is a 25000T domestic wastewater treatment plant with Orbal oxidation ditch process, design influent COD: 370mg/L, actual influent COD is around 150mg/L, TP is around 2mg/L, ammonia nitrogen is around 20mg/L, total nitrogen is higher than ammonia nitrogen by around 6mg/L, MLSS is between 2000~2500mg/L, SV is less than 15%. MLSS is between 2000~2500mg/L, SV is less than 15%, SVI is about 50ml/g, MLVSS/MLSS=0.5, COD of the effluent is less than 40mg/L, TP has almost no removal effect, ammonia nitrogen is about 8mg/L, and the removal rate of total nitrogen is less than 50%. Now the problem is that there is mud running in the outlet weir of the secondary sedimentation tank, which has never been interrupted since it started operation in July last year. In addition, each of the three ditches has four rotary brush aerator, now due to the low load, outside, in the inner circle were opened 1, 2, 2 aerators, the inner circle of dissolved oxygen in 2.0mg / L or so, the outer circle of the online monitoring of the OBP as low as -400. May I ask: What is the reason for the two sedimentation run mud, so that the control of the aeration method is appropriate?
A: The sludge has been aging to a certain extent, the activity is very poor, and the effluent brings out the aging deflocculated sludge. The main reason is that the sludge load is too low. Countermeasures: (1) Reduce the aeration time, can stop the operation of the outer ditch, sewage directly into the ditch; (2) may not stop the operation of the outer ditch, increase the amount of sludge discharge, significantly reduce the MLSS. both measures are to increase the sludge load, the first is to increase the sludge load by reducing the reaction time, the latter is to increase the load by reducing the sludge concentration, of course, in order to maintain the balance of the three-phase of water, gas, mud, the amount of aeration can not be too large. Of course, in order to maintain the three-phase balance of water, gas and mud, the aeration volume can not be too large.
Q: Week in and week out of the water distribution requirements are very strict. In fact, the week into the week out of the water distribution port have a block of baffle deep into the bottom of the two sinkers, but how much deeper is more appropriate, so far I can not find information. Because it is said to be directly from the foreign technology, it is not calculated, I wonder what your opinion on this issue?
A: You’re right, the perimeter of the inlet with a stall, it is estimated that there are many inlet holes under the inlet tank, by the water energy dissipation downstream, and then from the inlet stalls under the diffusion of the pool, the specific location I can not say, it should be in the water surface of the water at about 2 meters, right. I think the key technology should be uniform water distribution and water dissipation.
46. Q: How to identify sludge poisoning and sludge aging on the surface?
A: Generally speaking, there will be a developmental process of serious aging of sludge, while sludge poisoning will quickly cause cell disintegration. The ESS of the effluent increases significantly when sludge is aged and poisoned, and experienced people can distinguish it from the surface. The suspended solid particles in the effluent of sludge aging are relatively larger, mostly in the form of fragments. When the sludge is poisoned, the suspended solids in the effluent are relatively small.
Sludge poisoning and sludge aging can also be distinguished from the change in DO value, sludge poisoning process is faster, will make the DO rise in a short time, and sludge aging has a gradual process, DO rise process is also gradual.
47. Q: In the case of no change in the sludge intake of the sludge dewatering machine, the water content of the cake after dewatering rises significantly, what is the reason for this?
A: Excluding the operating condition of the dewatering machine itself, it may be a problem in the sludge dosing and tempering process, or it may be caused by the failure of the mixer in the sludge homogenization tank or the failure of the scraper in the sludge thickening tank.
Q: In recent times, the filter cloth of the sludge dewatering machine (belt filter press) of this unit often runs out of shape, what is the reason?
A: It is necessary to confirm whether the surface of the drum is bonded or worn, whether the parallelism of the roller shaft is good, etc. If the filter belt is bad, it should be replaced in time.
Q: Recently there is more oil in the wastewater, especially in the area of the wells, there is black scaled oil, how do you usually deal with it?
A: Firstly, we use manual cleaning, and then we use oil-absorbing felt or oil-absorbing medium to absorb the oil.
50. Q: Contact oxidation has many advantages in treating low concentration domestic wastewater (small communities), but it is difficult to meet the discharge standard (secondary) for N and P. How can the process be improved so that it can have the effect of removing N and P?
A: I think it is not that the contact oxidation method is not good at removing nitrogen and phosphorus, but it may be caused by problems in the control chain, such as the DO control of the aerobic tank must be higher than that of the activated sludge method, the anoxic zone must have adequate mixing function, and there are also factors such as alkalinity control.

51. Q: Now the thickener is full of floating mud, (the color is grey) we have prolonged the age of the mud and reduced the mud feed to the thickener. But why is there still such a phenomenon?
A: Such measures are not targeted, you should increase the amount of sludge from the thickener, so that the residence time of sludge in the thickener is reduced to prevent anaerobic fermentation.
52. Q: UNITANK process can be used in large-scale sewage plants, engineers who have used this new process said that it is not suitable for large-scale sewage plants in the application, because of the complexity of self-control, etc., and the effect of phosphorus removal is poor, is that so? Guangdong, a sewage plant is 220,000 tons / day, Shanghai, a sewage plant is 400,000 tons / day (recently), it is said that the operation of the overall situation is good, this process used in large-scale sewage plant in the end how? Please answer.
A: I think the UNITANK process is also suitable for large-scale sewage plants, but not suitable for high phosphorus removal requirements of sewage.
53. Q: Our aerobic tank for biological contact oxidation tank, the purpose is to reduce ammonia nitrogen from 30 to less than 10, the actual now add color developer and blank about the same. Add sodium carbonate to adjust the alkalinity, from the back of the sedimentation tank sludge reflux, due to the reflux is not good control, so sometimes it is mud and sometimes water. In the past, I found that the pH value of the whole aerobic tank dropped sharply with the direction of water flow when there was no sludge reflux, but not when there was sludge reflux, and the pH value of the effluent was guaranteed to be between 6.5 and 7. However, in recent days, we found that the pH value of the whole aerobic tank is on the low side, the front end is only 6.9, and the effluent is about 5.8 (all the indexes of influent and the amount of sodium carbonate remain unchanged, and the concentration of ammonia nitrogen is still undetectable), and even if we improve the state of sludge reflux in comparison with the previous state, it is also like this, may I ask what is the reason for this? In addition, the sedimentation tank behind our aerobic tank is a vertical flow sedimentation tank (148m3, water volume 30m3/h), there are four small sludge hoppers underneath, what measures should be taken to improve the state of sludge reflux in the aerobic tank under the existing condition?
A: The sludge (shedding biofilm) of contact oxidation sedimentation tank is generally not reflux, so we should first confirm whether the biofilm on the packing is normal? If the bio is too thick is to increase the amount of gas flushing, otherwise it will seriously affect the treatment effect.
pH drop so much some anomalies, theoretically not explain, because the feed water ammonia nitrogen is not high, nitrification process of hydrogen ions are not down more than one pH unit, the only possibility is that the sedimentation tank is too much sludge, in the anoxic sludge in the acidification of bacteria reproduction, refluxed to the aerobic tank after the occurrence of the acidification effect, of course, just speculation. Therefore, it is recommended to confirm the growth of biofilm on the filler, sedimentation sludge should not be returned to the flow, observe for a period of time and then say.
54. Q: (after the reply to the previous posting of the question) our system was not reflux, of course, because the design of ammonia nitrogen does not need to consider, previously not taken seriously the aerobic tank, monitoring found that the entire aerobic tank pH course downward trend (according to the direction of water flow 6.3-5.5-5.3-5.5-5.5). -5.3-5.1); at the same time, because of the ammonia nitrogen influent concentration increases cannot be handled, please come to see when there are two suggestions: one is to increase alkalinity, the second is sludge reflux. At that time, only the first suggestion was adopted, after adding sodium carbonate, ammonia nitrogen was indeed effectively removed, but the pH value still fell by a relatively large margin, and it is very difficult to control, and then in the sludge reflux, it was found that the stabilization of pH value has a better effect, and now it has been refluxed. I always feel very uneasy about the aerobic tank system, for one thing, through the aerobic process only converts nitrogen from ammonia nitrogen form to nitrate nitrogen, it doesn’t remove it from the water, and it doesn’t reduce the harm to the environment; for another, I often doubt the stability and durability of this system. Please help analyze and suggest solutions.
A: Paper is not always accurate, only for reference. If the pH of the biochemical tank can be stabilized after reflux, there is only one explanation, that is, denitrification occurs in the sludge in the settling tank, and the reflux liquid contains OH-, which can neutralize part of the H+ after entering the aerobic tank. Of course, it is only speculation, but no matter how, it shows that the system removes ammonia nitrogen with good results. If you want denitrification, I do not know whether the reaction time is enough, you can try, in the middle of the aerobic tank, set anoxic zone (residence time of about half an hour to an hour, a small amount of aeration, DO in 0.5 or less), so that part of the nitrate nitrogen can be removed, and stabilize the pH. also note that: aerobic tank in the latter part of the DO is higher, at least in the 3mg / L or more.
Supplementary note: my previous post in the analysis of the aerobic tank pH decline may be too much sedimentation tank sludge, in anaerobic sludge in the acidifying bacteria reproduction, reflux to the aerobic tank after the occurrence of acidification to; in the latter post and said that the sludge in the sedimentation tank denitrification occurs, the reflux liquid contains OH-, into the aerobic tank can neutralize some of the H+, can stabilize the pH of the aerobic tank. the two post seems to be a contradiction, but it’s to the Two possibilities for analysis, the former is if the sludge has anaerobic fermentation into an acidification reaction, the latter is likely to be anoxic and denitrification. Now it seems that the latter is more likely.
Q: Please teach the hydrolysis acidification tank dissolved oxygen should be controlled in how much range, the need to install aeration and mixing devices?
A: hydrolysis acidification tank is a mud method or membrane method, if it is a mud method with agitator can be, if it is a contact oxidation method, in addition to the installation of agitators, and then set up perforated pipe or aeration hose and other aeration devices, mainly to play an auxiliary role in the mixing. Do not worry about aeration will affect the effect of acidification, because the acidification pool load is high, filling some of the oxygen on its impact is negligible.
56. Q: the scale of 30,000 tons, using hydrolysis + biological contact oxidation treatment process, running for two years, if the two pumps open two sedimentation tank (load 0.9 or so) there is always floating mud phenomenon, and sometimes there are needle flocs. Affect the effluent SS. but in the opening of a pump, the effect is very good, please give a diagnosis!
A: The main reason is that the surface load of the second sedimentation tank is too small, because the settling performance of the biofilm is worse than that of the activated sludge method, and the design of its surface load should be at least twice as large as that of the activated sludge sedimentation tank.

57. Q: We are treating a mixture of paper wastewater and chemical wastewater, using a Carrousel 2000 oxidation ditch. In the past year, the ammonia nitrogen in the influent has been increasing, about 250, and the ammonia nitrogen removal rate is about 30-40%. What is the impact of this increase in ammonia nitrogen on the operation of the system? What should be done? If the influent ammonia nitrogen is controlled at 80, how can it be treated to meet the standard?
A: To confirm the sludge load and alkalinity and other nitrification conditions are met? If these basic conditions are met, you can increase the aerobic area of oxygenation, the inner return gate open some, the purpose is to make the anoxic area in front of the DO rise, so that part of the anoxic area also has a certain nitrification function.
58. Q: how to determine the hydrolysis acidification residence time? What criteria are used to determine the degree and effect of hydrolytic acidification of sewage?
A: Acidification time to be set through the operation of the test, generally speaking, acidification tank effluent pH decreased, BOD / COD ratio increased on the acidification effect.
59. Q: Our plant uses CASS process, the concentration of influent from last year’s COD in an average of 250ppm to the current average of 350ppm or so, while the influent suspended solids than last year, a lot more. Treatment cycle is 4 hours, intermittent aeration, take the side into the water while aeration for 2 hours, the influent concentration is not so high when the basic take 1 hour into the water, aeration is also 1 hour of treatment. At the end of the aeration stage, DO was basically kept above 2ppm, but the color of activated sludge was still black. There is no big change in the amount of water in each batch. Take the former way of treatment has been more than half a month, after treatment of the effluent is still maintained at 150ppm or so, suspended solids in the 50 ~ 60ppm, sludge is black, activated sludge flocculation is poor, the structure of the loose, it is difficult to see the primary micro-organisms, MLSS in the 1700ppm, the influent BOD in the 120 or so.
A: My initial judgment is that the aeration time is not enough, the reason is: after the increase of influent concentration, you have adopted a non-restricted aeration, on the surface is to increase the aeration time of one hour, in fact, not, because most of the time in the influent period, due to the low level of water, the oxygen utilization is very low, and more importantly, due to the load increase, the biochemical process has not yet been completed at the end of the last cycle of the aeration phase, in the static precipitation stage exacerbated the sludge anaerobic, to the next cycle of the aeration phase. Sludge anaerobic, to the next cycle of water intake stage although in the aeration, but the aeration of this period of time is actually only the recovery of sludge activity or part of the recovery, the actual biochemical reaction time did not increase much.
Process adjustment of the basic idea is right, it is recommended that: (1) rotate the pools of sludge mulled aeration to the mud color initially turned brownish-yellow before entering the water aeration; but also to confirm whether the nitrogen or phosphorus is enough? Because the nutrient ratio may be out of balance after the influent COD concentration increases. I just speculate from the surface, just for reference.
60. Q: pharmaceutical wastewater, sulfate 3000-4000, Cl-3000-4000, COD3000-4000, want to hang filler in the hydrolysis acidification tank, but a small test found that hanging film is quite difficult; I do not know if it is not the right choice of filler, or is it the reason for the higher Cl-? Environmental protection company said Cl- more than 3000 filler can not hang film.
A: Such Cl- concentration will affect the biofilm culture rate, but still can be hung on the membrane, it is best to introduce activated sludge or anaerobic sludge, which can increase the rate of hanging film. From the packing point of view, the soft packing is the most easy to hang the film, elastic packing is second, semi-soft packing is worse, but the elastic packing is easy to balling, to be used with caution!