What is the mechanism of activated sludge? Basic principles of activated sludge method

Activated sludge is a sludge-like floc formed by various organisms such as bacteria, fungi, protozoa and metazoans, and inorganic substances such as metal hydroxides. It has good adsorption, flocculation, biological oxidation and biosynthetic properties. It contains the microbial community used to purify wastewater and the organic and inorganic substances adsorbed.

Principle: The complex microorganisms in activated sludge form a complex food chain with organic nutrients in wastewater. The first to take on the task of purification are isoaerobic bacteria and saprophytic fungi, bacteria, especially globular bacteria, play the most critical role, and the well-functioning activated sludge is a mycelium composed of globular bacteria with filamentous bacteria as the skeleton.

Good sedimentation, with the normal operation of activated sludge, bacteria multiply in large numbers and begin to grow protozoa, which is a predator of bacteria. Common protozoa of activated sludge are flagellates, flesh caterpillars, ciliates and strawworms. When the activated sludge matures, sessile ciliates and seed worms are dominant; Metazoans are secondary predators of bacteria, such as rotifers, nematodes, etc., which can only appear when the dissolved oxygen is sufficient, so when metazoans appear, it indicates that the treated water quality is improving.

It can be seen that it is a very environmentally friendly method that uses microorganisms and other methods to purify pollutants.

Activated sludge aerobic microorganisms grow and multiply and condense together to form a colloid, on which other microorganisms coexist, and adsorb and intertwine inanimate solid impurities to form activated sludge. It is generally used to treat sewage and achieve water purification through microbial degradation of organic matter in water.

Maybe it's the principle of molecular structure.

<>1. Principle: activated sludge method.

It is the main method of biological treatment of wastewater in Changliang with live luctoli sludge as the main body. The activated sludge method is a sludge-like floc formed by the reproduction of aerobic microorganisms after a certain period of time by continuously introducing air into the wastewater. It is inhabited by microbial communities dominated by colloidal pellets, which have a strong ability to adsorb and oxidize organic matter.

Second, the process mechanism:

1. Adsorption stage: After the sewage and activated sludge come into contact, the organic matter in the water decreases rapidly in a short period of time, which is mainly caused by adsorption. Due to the flocculent activated sludge surface area.

It is large and has a polysaccharide mucus layer on the surface, which is conducive to adsorption.

2. Oxidation stage: under aerobic conditions, microorganisms oxidize and decompose part of the adsorbed organic matter to obtain energy, and part of it synthesizes new cells, which is much slower than the adsorption stage.

3. Floc formation and coagulation and precipitation stage: the bacterial organism synthesized in the oxidation stage quickly forms flocs and precipitates them by gravity to purify the water.

Activated sludge method.

The principle is to mix the wastewater with activated sludge and aerate it, so that the organic pollutants in the wastewater can be decomposed, and then the solids will be separated from the wastewater, and part of it can be returned to the aeration tank according to the demand.

in the service. Its process is basically a process similar to the self-purification of water in nature, but it is purified and strengthened by artificial methods, and the effect will be relatively better.

Specific purification process of activated sludge:

In the first stage, activated sludge needs to adsorb the organic pollutants in the sewage to the top of the microbial colloid, and some macromolecular organic matter will gradually decompose the pollutants into small molecules under the action of bacterial extracellular enzymes.

In the second stage of activated sludge, microorganisms will absorb and oxidize organic matter when oxygen is sufficient. Some of the nutrients obtained will be used for their own survival and development needs. The organic pollutants present in the sewage will be degraded and eliminated accordingly, so that the activated sludge will multiply and grow, and the sewage will be purified.

After the activated sludge has been purified, the remaining mixture will enter the secondary sedimentation tank.

The suspended activated sludge and other solids of the mixture will be separated from the water in this sedimentation tank, and the clear sewage will be discharged directly from the system. Then the precipitated and concentrated sludge is released from the bottom, and some of the sludge needs to be returned to the aeration tank to ensure the concentration of suspended solids and microorganisms in the aeration tank; The microorganisms that have completed their proliferation inside are gradually expelled from this system automatically. In general, the principle of activated sludge method is relatively complex, and it requires a certain amount of patience to be able to implement the principle well.

Activated sludge is mainly composed of four parts: the active microbial community with metabolic function; residues of endogenous respiration and autooxidation of microorganisms; refractory organic matter adsorbed by sludge flocs; Inorganic matter adsorbed by sludge flocs.

Background: Activated sludge is an aerobic biological treatment method, and the basic concept of activated sludge was discovered by Clark and Gage in England in 1912. They aeration of sewage for a long time will produce sludge and at the same time the water quality will be significantly improved.

Arden and Lockgtt then studied this phenomenon.

The aeration test was carried out in the bottle, and at the end of each day, the bottle was emptied and restarted, and they stumbled upon the fact that due to the imperfect cleaning of the bottle, the sludge attached to the bottle wall was treated better. Recognizing the importance of the sludge left behind on the bottle wall, they called it activated sludge.

Subsequently, before the end of the test every day, they put the aerated sewage still and precipitate, and only poured the upper layer of purified water, leaving the sludge at the bottom of the bottle for the next day's use, which greatly shortened the time for sewage treatment.

In 1916, the first activated sludge sewage treatment plant was built using this experimental process. Looking at these brown flocculent sludge under a microscope, you can see a large number of bacteria, as well as fungi, protozoa and metazoa, which make up a unique ecosystem. It is these microorganisms (mainly bacteria) that feed on the organic matter in the sewage, metabolize and multiply, and reduce the organic matter content in the sewage.

The first stage of the activated sludge methodThe organic pollutants in the sewage will be adsorbed on the surface of the microbial pellet by the activated sludge particles, due to its huge specific surface area and polysaccharide viscous substances. At the same time, some macromolecular organic matter is decomposed into small molecule organic matter under the action of bacterial extracellular enzymes.

The activated sludge method is an aerobic biological treatment method for sewageIts principle is mainly to make use of the metabolic action of microorganisms

Phase IIUnder the condition of sufficient oxygen, microorganisms absorb these organic matter, synthesize some of the organic matter into new cellular matter, and oxidize and decompose the other part of the organic matter. The organic pollutants in the sewage are removed due to degradation, and the activated sludge itself continues to multiply and grow, which can be said to kill two birds with one stone.

The principle of the activated sludge method is that the microorganisms eat the organic matter in the sewage, so that the sewage becomes clean water. It is essentially similar to the self-purification process of water bodies in nature in Chipai, while Chendan is only artificially strengthened, and the effect of sewage purification is better.