Location:Home > Problem
Summary of sewage treatment problems

1. The treatment of pharmaceutical wastewater by hydrolysis and biofilm contact oxidation process has been carried out for a month, and the COD of the influent and effluent is basically the same. SV30 was specially made today, the sludge volume is still good, the sedimentation is very fast, the supernatant is clear, the microscopic examination shows that the sludge should not be dead or poisoned. Best thinking is puzzled! Recently, the KF content in the water is high, and the COD change is not likely to be the reason?


(1) Initially, your wastewater is pharmaceutical wastewater, so sludge needs an adaptive process, as long as sludge or biofilm can grow, the treatment efficiency will be improved.

(2) In addition, the sludge you mentioned should be removed because of excessive inorganic flow into the system, so that the effective ingredients are low, settlement is fast, and treatment efficiency is low. In short, as long as the sewage sludge needs to be adapted to domestication properly, the incubation time will be longer than that of ordinary municipal sewage sludge.

2. What measures should be taken to effectively reduce COD for dissolved organic matter?


In the process, hydrolytic acidification and biofilm process can be used for pre-degradation, and then the traditional activated sludge process can be used for final treatment.

3. Wastewater from the production of tri (butoxyethyl) phosphate can now be treated with flocculation, but the COD index is too high - above 10,000 mg/L. What can be used to reduce COD? The organic matter discharge index can not be too high. What can we do?


(1) Look at the B/C ratio and confirm the biodegradability. If the biodegradability is higher than 0.3, the biological contact oxidation tank + traditional activated sludge process can be used.

(2) If the biochemical property is not good, add hydrolysis acidification section. If the water quantity is not high, if it is several tons per day, it can also be handled by entrusting professional units to transport abroad.

4. Recent receipt of a project is an oily wastewater discharged from a vegetable oil plant. However, this wastewater is discharged into a nearby pond and is white. It is estimated that it has been emulsified. Now it is required to treat these wastewater. It is not necessary to require that the COD treatment meet the standard, as long as it can be slightly reduced and the treated wastewater is clear. What should we do?


It can be demulsified first and precipitated in coagulation. Purchase calcium chloride for demulsification, the specific dosage you can decide through a simple test. After coagulation and precipitation, the clarity of the effluent should not be a problem.

5. How to improve the treatment effect in anaerobic and anoxic stages?


To improve the treatment effect of anaerobic and anoxic stages, the residence time, PH value, temperature and other aspects are mainly controlled to ensure the effective treatment of organic matter by microorganisms. For example, if the influent PH is abnormal, we should try to adjust it, either acid-base adjustment or water volume adjustment.

6. Debugging a printing and dyeing wastewater plant. Their technological processes are flocculation, sedimentation, anaerobic, contact oxidation, secondary sedimentation and effluent. In front of them, the treatment effect of physical and chemical section is good, the anaerobic tank may not be ideal, the filler of contact oxidation tank is saturated, and the treatment effect is not good. But the manufacturer does not want to change the filler. Is there any way to improve the treatment efficiency?


Poor treatment is not necessarily a problem in contact oxidation tanks, because your printing and dyeing wastewater may be more difficult to degrade. In order to improve the treatment efficiency, it is necessary to improve the effect of anaerobic tank in order to improve the treatment efficiency of contact oxidation tank.

7. In the treatment of saponin wastewater, the following problems are encountered first. The maximum desulfurization efficiency of lime can only reach 50%. After 50% removal, the sulfate content is still 56,000. After the sulfate content is high, one is to affect the anaerobic effect, the other is that the calcium sulfate deposits seriously. Is there any solution? COD 12000-20000mg/L, PH3-4, SO42-8000-10000mg/L. The comprehensive wastewater has the characteristics of poor biodegradability, high pollution load, high SO42-content and high chroma. It also contains water-soluble saponins, tannins, pectin and other substances which are toxic to microorganisms. It is a kind of high concentration and refractory organic wastewater. What is the solution? Now I want to add aluminium salts to precipitate aluminium salts, but it is still in the test stage. Is that OK?


(1) This should be caused by too much sulfate in your raw water. Serious precipitation is mainly caused by loose precipitation of calcium sulfate, and some flocculants can be added to assist precipitation.

(2) Such wastewater does not know the amount of treatment per day? Generally, if the amount of water is not large enough, we can consider entrusting external professional units for treatment, then the cost of treatment has advantages. Technologically, it is still difficult to discharge such wastewater up to the standard. Domestic sewage can be introduced. If the amount of water is suitable, the system can be stabilized by cooperating treatment. Otherwise, it will be more difficult.

8. We all know that increasing sludge concentration can enhance the removal efficiency of COD, N and P under the condition of constant tank volume, but how to judge the tank volume is insufficient and needs to be expanded.


Mainly depends on whether MLSS is reasonable and the removal rate and oxygen supply.

(1) MLSS is generally not higher than 4000mg/l. If it is high, there will be problems in sedimentation and oxygen supply.

(2) Removal rate, naturally see whether it can meet the requirements of qualified effluent.

(3) Oxygen supply, if MLSS is too high, will not keep up with oxygen supply, in many cases may be less than 1.0 mg/l.

9. In the same system, the total amount of influent pollutants is the same, the reaction time is the same, the concentration of one kind of large water pollutants is low, and the concentration of one kind of small water pollutants is high.


It is difficult to achieve the same residence time with different water volume. Therefore, if the conditions are the same, it depends on whether the system runs at high load or low load. If not uniform, there will be shocks.

10. At present, a stream of electroplating wastewater is debugged. The main types of electroplating are copper-tin, copper-zinc and copper-silver plating. There is no nickel and no coke-copper. The use process is cyanide secondary cyanide breaking, chromium reduction, and then comprehensive use of chemical mixing treatment. Now I encounter the situation that the concentration of TCU in the effluent is above 35 PPM, and the removal rate of TCU in the effluent is about 1-2 PPM. The removal rate has reached 94%-97%, but still not up to the standard (TCU < 0.5). In chemical mixing treatment, PH is adjusted to about 9.0 to make it precipitate. But TCU can't fall down. What's the way? It was found that the concentration of TCU in oil separating tank and chromium system tank was very high, both exceeded 40. After treatment, both wastewater went to comprehensive regulating tank.


Oxygen. Of course, it can also reduce sludge concentration.

11. What are the factors affecting COD removal rate?


The removal rate is not low. Can we try to reuse the treated effluent to dilute the raw water? After general dilution, the treatment will be better. Water quality of primary and secondary sedimentation water: COD 600 mg/L BOD 90 mg/L are both approximate values. Secondly, the effluent quality of three precipitations: COD350mg/l BOD55mg/L (these two are also approximate values).

12. The failure of desliming machine caused the concentration of activated sludge in the system to rise to more than 9,000, ammonia nitrogen intake 36, effluent 30. How to reduce ammonia nitrogen under the condition of high concentration? How to improve the removal rate? After high concentration, there will be insufficient oxygen supply, resulting in the reduction of ammonia nitrogen removal rate, can it improve the dissolution rate?


Probably three factors influence:

(1) The influent quality determines the removal rate. Generally, the removal rate of refractory industrial wastewater is lower than that of domestic wastewater.

(2) Whether the design of treatment facilities matches the current situation, such as the problem of excessive hydraulic load.

(3) Whether the operation of the system can be achieved, such as excessive sludge concentration control, excessive aeration, lack of nutrients, etc.

13. A high-viscosity sewage containing polyacrylamide is now encountered and is ready to be treated by biological method. What is the upper limit of viscosity required for biological treatment of wastewater? If the viscosity is too high for biological treatment, is there any way to reduce the viscosity?


If you have medicines in this wastewater, you can test BOD5 to see its biodegradability. In addition, if the year is big, the following countermeasures can be taken:

(1). Introduce other wastewater for treatment and dilution.

(2). Considering multi-reflux in design, it can also play a diluting role.

(3). As for the viscosity, I don't think it's a big problem if it doesn't affect aeration. We can also test BOD5 with wastewater of different viscosity to see the highest removal rate at that viscosity or concentration.

14. CASS process for domestic sewage treatment, recently, ammonia nitrogen is unusually high, in the range of 60 ppm, cod 250-320 (design influent ammonia nitrogen is 30, COD320), the effluent ammonia nitrogen has been unable to fall down, and the effluent ammonia nitrogen of the pond with 2 hours aeration is 30-40 (normal operation is 4 hours, inflow aeration is 2 hours, precipitation is 1 hour, drainage is 1 hour). In order to improve the removal rate of ammonia nitrogen, several ponds are prolonged aeration for 3 cycles, namely aeration. The gas time is 6 hours. But the ammonia nitrogen in the effluent can not be reduced between 10 and 13. What's the matter? According to the data, the conventional influencing factors are: temperature: about 12 at present; PH: the pond is about 6.8-7.2 at present; mud age is very long, over 30, there should be 50; the proportion of carbon source in the influent is insufficient, and COD in the effluent has exceeded the standard of 70-100 in recent days. Excuse me: How to improve the removal rate of ammonia nitrogen? Why the COD is still high (the test data should be basically accurate)? In winter, I microscopy microorganisms, biochemical pool microorganisms have been unsatisfactory, there are a small number of Clonorchis and clubworms, but the individual is small and inactive. On the contrary, I took the sludge from the wall of the pond for microscopic examination, and there were a large number of Acanthopanax, a lot of Acanthopanax. Today, I had a microscopic examination of several of the pools. One had a large number of branching worms, nematodes and rotifers; the other had only nematodes. Why is the sludge mirror of the pond poor, the wall of the pond good, how to understand?


(1) PH to see if it can be further raised, as far as possible not less than 7; ammonia nitrogen at the initial stage of precipitation and the end of drainage should be detected, if the later data is high, it means that the time of precipitation and drainage should be shortened.

(2) Excessive aeration. The wall of the pond is microbial micelle, which is not easily affected by aeration.

15. Debugging an industrial wastewater treatment plant with liquid crystal display screen, which had been operating normally before, now the sludge sedimentation performance has become very poor. The water volume of the secondary sedimentation tank is a little larger, a large number of sludge will run away from the effluent immediately, and enter the subsequent high-efficiency sedimentation tank after adding medicine and precipitation (PAM and PAC), sludge will be discharged into the concentration tank, because the treatment capacity of the dewaterer is smaller than that of the physicochemical sludge production. Biomass, often a large number of physicochemical sludge into the biochemical tank, so that sludge sedimentation performance has not been improved. Specific operation parameters are as follows: treatment water volume is about 20000m3/d, influent ammonia nitrogen is over 30, TN is about 40-50, COD is about 200, BOD/COD is about 0.45, TP value is unstable, between 0.5-2, biochemical tank MLSS is about 2200 before, because physicochemical sludge has surged to over 3000, SV is about 50, sludge concentration has been controlled to 1700, SV is about 45, DO is controlled. The sludge sedimentation performance is still not improved after 3-5 mg/l operation for more than a month. Except for ammonia nitrogen and TN, the other conventional indexes are normal. COD effluent is about 35. What are the suggestions?


If the settlement ratio is 45, it is not as serious as the drifting mud in the secondary sedimentation tank. Whether your water intake has exceeded the design value, or if there is a short flow in the sedimentation tank.


Copyright © Jiangsu Welpep Environmental Protection Technology Co., Ltd.


Working hours:8:00-17:00