Activated sludge treatment process includes which methods

The common activated sludge process includes the following four kinds:

(1) Ordinary activated sludge method

Also known as the traditional activated sludge method, it is the activated sludge operation method that has been used in the early days to the present. With the flow of sewage along the length of the pool, the degradation of organic matter in the pool mainly undergoes two phases of adsorption and metabolism, and the microorganisms also undergo a complete growth cycle from logarithmic growth at the beginning of the pool, decelerated growth in the middle, to endogenous leveling absorption at the end of the pool.

The traditional activated sludge system is extremely effective for wastewater treatment and is more stable in operation, but there are many problems. The aeration tank of this activated sludge method is characterized by high front-end and low back-end load due to the degradation effect of microorganisms, so in order to avoid insufficient supply of ****oxygen at the front end, the organic load of influent should not be too high, or take a gradual reduction in the supply of nutrients.

Basic flow of activated sludge treatment process

(2) Oxidation ditch method

The plane structure of oxidation ditch presents an oval ring, and the sewage in the ditch circulates along the ring ditch. It is actually a variant of the activated sludge method, in which the processes of aeration, sedimentation and sludge stabilization are completed in a single structure. Because the sewage and activated sludge continuously circulate in the aeration channel, it is called "circulating aeration tank" or "terminal-free aeration tank". Oxidation ditch method has a strong hydraulic retention time, sewage into the oxidation ditch immediately after the large that is diluted by a large amount of water, so it has a lower organic load and longer sludge age.

Compared with the traditional active pollution method can be omitted regulating pool, primary sedimentation tank, pollution pool, some can also omit the two rivers sedimentation tank. At the same time, reasonable oxidation ditch operation can achieve the effect of simultaneous nitrogen and phosphorus removal.

(3) two-stage activated sludge method

Also known as AB two-stage activated sludge method. It divides the activated sludge system into two stages, i.e., A section and B section. Its purpose is to make full use of the population characteristics of microorganisms, respectively, to create a suitable environment for them, so that different micro-populations get good proliferation, so as to effectively degrade the pollutants in the water. According to the different ways of connecting the aeration and sedimentation tanks, it can be divided into series and parallel methods, and the latter is also called enhanced aeration method. Compared with the traditional activated sludge process, the two-stage activated sludge process can save a large amount of aeration, and at the same time, less residual sludge is produced.

(4) Sequential batch activated sewage sludge method

This refers to the use of cutting time, the original need to be completed in several pools of water intake, reaction, sedimentation, decanting and idling of a set of five phases of the activated sludge method in a pool to complete.

The method has the following advantages: due to the use of complete mixing, completed in a pool, the method requires fewer structures and occupies less maintenance of gas time is short, aeration efficiency is high, the same also makes it has a better shock load resistance. In addition, sequential batch activated sludge process operation is flexible and adaptable; it can be timely adjusted according to the changes in sewage water quality and operation, and it also has good effect on nitrogen and phosphorus removal. However, the volume of the sequential batch activated sludge method single pool is very large, and usually count on the need for better automation and control equipment, operation and management of complex.