Sewage plant common problems of practical treatment methods, done!

水量不足

When the water is insufficient, the process control is as follows:

1. Lift the pump room to keep the water pump flowing smoothly, but avoid running the pump at a low level。

2. If the water quantity is less than 50% of the designed water quantity, the sewage treatment system should run in a single group (double group system) or intermittently (single group system), pay attention to monitoring the operating parameters of the biochemical system (DO, pH, MLSS, etc.), and adjust the process in time。

3. Reflux ratio is controlled at 50-100%。

4. Half of the secondary sink。

When the water quantity exceeds the design load, the process control is as follows:

1. Lift pump house to full capacity production, but does not exceed the design load variation factor。

2. The coarse and fine grille should be opened continuously on site and the grille slag should be removed in time。

3. At the early stage of the water surge, the aeration equipment of the sewage treatment system should be fully turned on, pay attention to monitoring the operating parameters of the biochemical system (DO, pH, MLSS, etc.), and adjust the process in time。

4. Increase the sampling frequency of supernatant of biochemical tank, effluent of secondary sedimentation tank and total effluent。

5. The secondary sedimentation tank has been put into use。

6. With the gradual stability of the biochemical system, the increase of DO, and the low ammonia nitrogen of the system, it can be considered to reduce the number and opening frequency of aeration equipment。

When sludge swelling occurs, the staff on duty should immediately report to the production supervisor, notify the laboratory to immediately collect water samples, determine the water sample BOD, COD, MLSS, DO, PH, SV and biological microscopy, and then decide the following measures according to the site situation。

The most prominent performance of sludge bulking is that the sludge settling performance index SVI is greater than 150%。In the sewage, such as more carbohydrates, insufficient dissolved oxygen, lack of nitrogen, phosphorus and other nutrients, high water temperature or low pH value, it is easy to cause sludge swelling。In addition, overload, too long sludge age or small organic concentration gradient will also cause sludge swelling。Poor drainage of sludge will cause swelling of bonded water-based sludge。

The process adjustment for the causes of expansion is as follows:

1. Oxygen deficiency and high water temperature increase aeration, or reduce water temperature, reduce load, or appropriately reduce MLSS value, so as to reduce oxygen demand;

2. If the sludge loading rate is too high, the MLSS value can be appropriately increased to adjust the load, and if necessary, the water should be stopped for a period of time.

3. Lack of nitrogen, phosphorus and other nutrients, can be added nitrification sludge or nitrogen, phosphorus and other components;

4. If pH value is too low, lime can be added to adjust pH(6-8);

5. A large amount of sludge loss, can be added 5-10mg/L ferric chloride, promote condensation, stimulate the growth of bacterial micelles, can also be added bleach powder or liquid chlorine (according to the dry sludge of 0.3%-0.6%), inhibit filamentous reproduction, especially to control the swelling of the sludge。In addition, adding asbestos powder, diatomaceous earth, clay and other substances also have a certain effect。

When the sludge disintegration phenomenon occurs, the performance phenomenon is: the treatment water quality is turbidity, the sludge flocculation is fine, the treatment effect is worse。

The process should be adjusted as follows:

1. When the influent water quality is analyzed and it is determined that the sewage is mixed with toxic substances, it should be considered that this is the result of the new industrial wastewater, the influent water should be reduced and the aeration rate should be increased to restore the activity of the biochemical system as soon as possible。

2. Adjusted intake。

3. Adjust the amount of returned sludge to control MLSS。

4. Adjust the aeration rate to control the dissolved oxygen in 2.About 0mg/L。

5. Adjust the sludge discharge。

The phenomenon of the sludge floating up in bulk in the secondary sedimentation tank is not caused by corruption, but because the sludge age in the aeration tank is too long, the nitrification process is sufficient, the denitrification is produced in the sedimentation tank, the nitrate oxygen is used, and the nitrogen is released as a gas attached to the sludge, so the specific gravity is reduced and the whole block floats up。The so-called denitrification refers to the reduction of nitrate to ammonia or nitrogen by denitrifying bacteria。Denitrification generally has dissolved oxygen below 0.Occurs at 5mg/L。

The test shows that if the mixture with a high nitrate content is allowed to settle at rest, the sludge can settle well at the beginning of about 30-90mm, but it can be seen soon that the nitrogen generated by denitrification forms small bubbles in the mud, making the sludge float to the surface of the water as a whole。In the sludge settling ratio test, only check the settling performance of sludge 30mm。

Therefore, the denitrification of sludge is often ignored。This is a phenomenon that should be paid attention to in the operation of activated sludge method, in order to prevent the occurrence of this abnormal phenomenon, measures should be taken to increase the sludge return flow or timely exclusion of residual sludge, or reduce the concentration of mixed liquid sludge, shorten the age of sludge and reduce the concentration of dissolved oxygen, so that it is not carried out to the nitrification stage。

原因:

Hydraulic load impact or long-term overload, due to short flow and reduce the residence time, so that the floc before settling out of the weir。

The solution:

Evenly distribute hydraulic load;Adjusting the uneven inlet and outlet facilities, reducing the impact of impact load, is conducive to overcoming short flow;Flocculant is added to improve the settling performance of some difficult suspensions, such as the flocculation of colloid or emulsified oil particles;Adjust the load of residual sludge entering the primary sedimentation tank。

原因:

Sludge adhesion, algae growing on the weir, or scum and other objects stuck on the weir, resulting in dirty water weir, and even some weir blockage resulting in uneven water。

The solution:

Frequent removal of sewage stuck in the weir;Proper addition of medicine and disinfection to prevent the growth and accumulation of sludge and algae in weir。

原因:

Sludge residence time is too long, organic matter corruption。