What is the reason for the high sludge settlement ratio?

Emergency measures. The main method of temporary emergency is to add drugs to enhance the sludge sedimentation performance or directly kill filamentous bacteria. The addition of coagulants such as iron salt and aluminum salt can directly improve the compactness of sludge and ensure the precipitation of water.

In addition, adding some chemicals, such as chlorine, to the reflux sludge can also eliminate sludge swelling. The addition of hydrogen peroxide and ozone can also have the effect of destroying filamentous bacteria.

This method can generally reduce the SVI value quickly, but these methods do not fundamentally control the reproduction of filamentous bacteria, and once the dosing is stopped, the sludge swelling phenomenon can make a comeback. Moreover, the dosing may destroy the microbial growth environment of the biochemical system, resulting in the reduction of the treatment effect, so this method can only be used as a temporary emergency.

Improve the biochemical environment.

When sludge expansion occurs in sewage plants, it is generally impossible to solve it from the change of process flow, pool type and aeration mode, and can only inhibit or eliminate the overgrowth of filamentous bacteria by changing the microbial growth environment in the biochemical tank on the basis of the running process. With different processes and water quality, it is difficult to have a one-size-fits-all solution.

However, there are several problems that should be paid attention to in biochemical processes.

Control of the nature of the effluent.

First of all, the pH value should be checked and adjusted, when the pH value is lower than 5, it will not only be beneficial to the sludge expansion, but also will have a certain harm to the normal biochemical reaction, so when the pH value is low, it should be adjusted in time. In addition, in the cold areas of the north, you should pay attention to the water temperature in winter, if the water temperature is low, it should be heated, because low temperature will also lead to the occurrence of sludge expansion.

The use of blast aeration can effectively improve the water temperature in winter. When the nutrients in the sewage are insufficient or unbalanced, they should be supplemented. The content of N and P should be controlled at BOD:

n：p=100：5：

1 or so. If there is digestion before the biochemical system of sewage treatment, the low molecular weight organic acid produced will be conducive to the growth of filamentous bacteria, and the wastewater can be pre-aerated in the conditioning tank to improve.

Generally, an air diffuser is used to aerate the regulating tank with an effective water depth of 3-5 meters, and the air supply can be controlled at 3 meters of wastewater. It keeps the wastewater in the regulating tank fresh and effectively prevents odors caused by anaerobic. Maintaining sufficient dissolved oxygen in the pool is particularly important for biochemical systems with high loads, 3) DO> should generally be controlled at least 2 mg L.

The sludge in the sedimentation tank should be discharged or refluxed in time. Prevents it from occurring anaerobic. If anaerobic phenomenon occurs, various gases produced are adsorbed on the sludge, which will also make the sludge float and the sedimentation performance will deteriorate.

In addition, anaerobic sludge backflow can also lead to the proliferation of filamentous bacteria. In this case, in addition to discharging sludge and removing dead corners in the sedimentation tank, and shortening the residence time of sludge in the tank. The do value of the aeration tank should also be increased.

The water entering and exiting the sedimentation tank retains relatively dissolved oxygen. Or the sludge can be aerated and regenerated before it flows back into the biochemical tank.

High inlet water load.

The sludge inlet load is high, and the incomplete decomposition of organic matter affects the sedimentation performance of sludge, and the sedimentation effect becomes worse, and the sedimentation ratio becomes higher. It can reduce the load, reduce the total amount of COD in the influent water, improve the dissolved oxygen, and gradually restore the sludge performance.

The sludge sedimentation treatment method is as follows:

1. Measures to improve sludge sedimentation.

Long-term low-load operation leads to fluffy sludge and poor sedimentation, and the deterioration of sludge sedimentation leads to enhanced adsorption, which is the active response of microorganisms to changes in external environmental conditions in order to obtain more organic matter. The sludge sedimentation performance can be improved by increasing sludge discharge, shortening sludge age, speeding up sludge renewal, or adding flour, starch and other sources of leakage.

Under the condition of low dissolved oxygen concentration, sludge loosening and swelling can be caused, which is mainly caused by the denitrification of microorganisms using their own carbon source under low dissolved oxygen conditions.

By increasing the aeration and increasing the concentration of dissolved oxygen, the sludge sedimentation performance can be restored to normal, but the aeration volume can not be too high, the aeration capacity is too large, and the microorganisms will deplete the external available carbon source, and the activated sludge will also be loosened for 1 time, usually the DO can be controlled at 1 to 3mg per l.

2. The ratio of n and p is controlled within a suitable range.

When the pH value in the aeration tank is low, the sludge sedimentation will deteriorate, and the pH value can be controlled above by adding alkaline substances such as flake alkali. <>

Reasons for poor sludge sedimentation performancePoor sludge flocculation, reduced density of activated sludge, etc.

1. Poor sludge flocculation.

In this case, microscopic inspection of activated sludge shows that the index micro-lead stupid components are mainly composed of swimming protozoa, such as echinocercosis, bean insects, and grenade insects, and the reason for this characteristic is that there are many free bacteria in the activated sludge, which provide food for swimming protozoa**.

After the sludge was left for 30 min, the sludge was still dispersed, and there was no obvious interface between the supernatant and the sedimented sludge. In both high BOD load and low BOD load, high BOD load sewage enters the aeration tank, under the action of oxygen, bacteria grow rapidly, and the amount of new sludge grows very fast, which is inevitable in the process of activated sludge from new generation to maturity.

In the case of low BOD load, the sludge is in a state of starvation, at this time, the organisms will produce selectivity, survival of the fittest, and the microorganisms that are not suitable for this environment will die naturally, resulting in sludge disintegration, which will also lead to the decline of activated sludge sedimentation performance.

2. The density of sludge decreases.

In the case of high aeration, the sludge is agitated vigorously, in which case the colloidal pellets can easily adsorb oxygen and thus rise in the sedimentation tank. In the state of high aeration, the sludge oxidation rate is accelerated, and the sludge will be partially oxidized at this time, and the sludge will show a slight whitish phenomenon from the sludge color, and the sludge itself will be oxidized and the density will decrease.

The determination of inorganic matter can be analyzed by two indicators, MLSS and MLVSS, and the proportion of MLVSS in MLSS is between 65% and 70%, which is higher than this value, indicating that there are too many organic components and are prone to mud running.

Solutions to the decline in sedimentation performance:

After the positive increase of water temperature, the BOD load is gradually increased, and the BOD load of municipal sewage can generally be maintained, and the sludge age is controlled for 18 days in winter. More than 12 days in summer is sufficient.

The sedimentation of sludge can be gradually improved by adding powder carbon, diatomaceous earth or lime in the case of a unit of mud age, and gradually increasing the amount of inorganic matter. The improvement of sludge sedimentation makes the process very slow, often taking a year or more, so it is necessary to combine emergency and routine operations. <>

Summary. Hello dear, glad your question, what is the matter with the sludge settlement ratio is very small? to help you find the following answers: sludge aging, the reason for the small sludge settlement ratio is the sludge aging phenomenon.

What is the reason for the small sludge settlement ratio?

Hello dear, glad your question, what is the matter with the sludge settlement ratio is very small? to help you find the following answers: sludge aging, the reason for the small sludge settlement ratio is the sludge aging phenomenon.

Dear, the SV30 is less than 10, and the MLSS is so high, then the SVI is very small. It is estimated that the sludge aging phenomenon has occurred. When making SV, you should not pay attention to the final value, but also observe its settlement process.

See if the supernatant has some tiny flocs. There is also the case where the content of inorganic components is too high.