What is the aeration method

3, activated sludge method is the use of a large number of microorganisms containing activated sludge, sewage organic or inorganic pollutants in the absorption and oxidative decomposition, so that the sewage can be purified method. Due to the large capacity and high efficiency of this method, it has been widely used in various kinds of sewage treatment. Activated sludge is an aerobic biological treatment method. At present, the following aeration methods are often used.

Ordinary aeration: Ordinary aeration method is also known as traditional aeration method. It is characterized by the process of sewage treatment, biological adsorption and biological oxidation stage in the same aeration tank continuously.

Gradual reduction of aeration: Installation of air diffusion equipment in the aeration tank, along the length of the pool gradually reduced, so that the supply of air is also gradually reduced accordingly.

Gradual aeration: sewage into the aeration tank, into several entrances into the aeration tank, can make the oxygen demand along the length of the aeration tank to become uniform.

Adsorption and regeneration aeration method: this method is the aeration tank is divided into two pools, so that the adsorption and oxidation processes are carried out in two pools. Adsorption pool is also known as contact pool, oxidation pool is also known as regeneration pool.

Completely mixed aeration method: it is characterized by the aeration of the pool of sewage, air and reflux sludge to fully and evenly mixed, so that the pool at each point of the water quality is basically the same. So that the oxygen demand at all points in the pool is also uniform.

4, biofilter method. It is one of the aerobic biological methods, the main device is a biofilter. Biofilter is equipped with filter media, on which there is a biofilm, this method is the use of biofilm in the water for organic adsorption and oxidative decomposition.

This is a reliable method of sewage purification and treatment, especially some difficult to deal with

Industrial wastewater, often resort to biofilter method. Biofilter structure

There are mainly three kinds of pool bed type, tower type and biological turntable.

5, biological pond. The use of naturally occurring or slightly man-made ponds in the growth of microorganisms to deal with organic sewage treatment facilities, called biological ponds. According to the microbial activity of the characteristics can be divided into aerobic biological ponds, and gas biological ponds and anaerobic biological ponds. Aerobic bioponds are shallow, sunlight can penetrate, load is small, all the sewage can be aerobic bioconversion; partially aerobic bioponds are deeper, sunlight is half-permeable, load is larger, the upper layer of the pool for aerobic bioconversion, the bottom and the sludge layer of anaerobic bioconversion; anaerobic bioponds are deeper, the load is large, the sewage for anaerobic bioconversion.

3 Technical progress of biochemical treatment method

With the wide application of biochemical treatment method, the research on the improvement of biochemical treatment technology is particularly active, especially on the improvement of activated sludge method.

311 New progress of activated sludge method

1) Pure oxygen aeration method. The first pure oxygen aeration sewage treatment plant was built in 1968 by the United States. Recently, due to the decreasing cost of manufacturing oxygen, the oxygen aeration method has been widely used.

②Deep water aeration method. Increase the depth of the aeration pool can increase the pressure of the pool water, thereby increasing the solubility of oxygen in the water, the rate of oxygen dissolution should also

increase, therefore, the deep-water aeration pool of dissolved oxygen in the water to be higher than the ordinary aeration

pools, is generally the depth of the pool by the original 4 m to about 10 m. The depth of the pool is generally the original 4 m to 10 m or so.

3 jet aeration method. Sewage and sludge mixture through the jet, due to high-speed jet and generate negative pressure, so there is a large amount of air inhalation, air and the mixture for full contact, improve the oxygen absorption rate of sewage, so that the efficiency of the treatment of sewage has been improved.

④Injection of chemical coagulant and activated carbon method. In the aeration tank of activated sludge method, chemical coagulant and activated carbon are added, which is equivalent to biochemical treatment and physical treatment at the same time. Activated carbon can be used as a carrier for microorganisms and assist the role of solid sedimentation, BOD and COD removal rate increased, so that the water quality purification.

⑤Biological contact oxidation. This is both the activated sludge method and biological filtration method features a new type of sewage treatment method, contact oxidation tank instead of the general aeration tank, contact sedimentation tank instead of the commonly used sedimentation tank.

6 pipeline aeration. This method is to make the sewage in the pressure pipe for activated sludge aeration, while the longer distance transportation. Because of less equipment, investment costs and operating costs can be reduced.

312 New progress in biological filtration

①Improvement of biological turntable. Improve the performance of the turntable material and increase the diameter of the turntable, which can increase the surface area of the turntable, which is conducive to the biochemical process of microorganisms. According to the working principle of the turntable, recently developed into a biological rotor, the cylinder can add a variety of filter media, thus increasing the surface area of the biofilm.

②Active biofilter. Its structure and biofilter is basically the same, the same operation mode, only in the sewage mixed with a certain amount of activated sludge.

And there is also a return flow of activated sludge and sewage mixing, and together into the biological

Biological filter. Because the biofilm on the filter media and the mixture itself contains activated

sludge have oxidizing effect, so the treatment efficiency is relatively high, the quality of the water.

BOD removal rate of more than 90%.

3 Enzyme treatment of sewage. Enzyme treatment of sewage, although earlier used by people, but the enzyme is generally easy to dissolve in water, can not be recovered after use, thus affecting the promotion. In recent years, the emergence of solid-phase enzyme preparations (by immobilizing enzymes on polymers and carriers) has prevented the loss of enzymes.