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Sewage plant common problems of practical treatment methods, done!

来源:From the network      Release time:2022-05-31       Number of readings:



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。

Water quantity exceeds design load

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。

Sludge bulking

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。

Sludge disintegration

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 denitrification effect of sludge is poor

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。

Sedimentation basin anomaly

The effluent contains a large number of suspended particles


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。

The effluent weir is dirty and uneven


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。

Sludge rising


Sludge residence time is too long, organic matter corruption。

The solution:

The first is to keep the mud discharge in time, so that the sludge does not stay in the secondary sedimentation tank for too long;Check the failure of mud discharge equipment;Remove sludge from settling tank walls, parts or some dead corners。The second is to increase the oxygen supply at the end of the aeration tank so that there is enough dissolved oxygen in the mixed liquid entering the secondary sedimentation tank to keep the sludge from being treated in the denitrification state。For sludge rising caused by denitrification, the discharge of residual sludge can also be increased, SRT can be reduced, and nitrification can be controlled to achieve the purpose of denitrification control。

Scum overflow


The location of the scum removal device is improper or the removal frequency is too low, and the scum residence time is long。

The solution:

Maintenance of scum scraping device;Adjust the scum scraping frequency;Strictly control the amount of scum produced。

The sludge pipeline or equipment is blocked


The content of precipitable-prone substances in the sludge of the secondary sedimentation tank is high, and the caliber of the pipeline or equipment is too small, and it is caused by infrequent work。

The solution:

Set up clearing measures;Increase the frequency of sludge equipment operation;Improve sludge pipeline or equipment。

Mud scraper is faulty


The mud scraper stopped running due to excessive load and other reasons。

The solution:

Shorten the time of mud storage and reduce the amount of mud storage;Check whether the scraper is stuck by masonry, tools or loose parts;Timely replacement of damaged links, scraper and other parts;Prevent the accumulation of ice on the surface of the sedimentation tank;Slow down the speed of the mud scraper

Biochemical tank foam problem

In the operation and management of sewage treatment plant, when it is found that a large amount of foam is produced in the biochemical tank。Report immediately to the production supervisor and decide what action to take to remove the foam according to the situation on site。

Generally, the following three measures can be taken: First, spray the water surface of the biochemical tank with tap water or treated effluent。Second, add defoamer, such as diesel oil, kerosene。Third, increase the amount of returned sludge and increase the concentration of activated sludge in the biochemical tank。

The effect of biological phosphorus removal is poor

The anaerobic zone should be maintained in a strictly anaerobic state, that is, the dissolved oxygen is below 0.2mg/L, at this time the phosphorus accumulating bacteria can effectively release phosphorus to ensure the subsequent treatment effect。The dissolved oxygen in the aerobic zone should be maintained at 2.Above 0mg/L, phosphorus accumulating bacteria can effectively absorb phosphorus。

因此,当出水出现总磷不达标时(>1 mg/L),则视具体情况可通过调整鼓风机的充氧量和调节回流污泥量使得溶解氧在厌氧区控制低于0.2mg/L, the aerobic zone is controlled above 2mg/L。

Source: From the Internet