Aeration process commonly used in sewage treatment

Aeration biological filter, also calls the BAF, invented in the late 1980 s and early '90 s biological membrane method sewage treatment technology, can effectively remove the harmful material such as SS, COD, BOD, and its maximum processing can reach hundreds of thousands of tons a day, and gradually developed to nitrogen and phosphorus, in Europe and the United States has been widely used, has strong practicability.

Basic principle

A certain amount of granular filter material with small particle size is loaded into the filter tank. As the surface of the filter material grows with high activity biofilm, it can be aerated in the filter tank. When the sewage passes by, the oxidation degradation of the filter material can be used to achieve the effect of rapid purification of sewage. At the same time, due to the compaction state of the filter material when flowing through the sewage, the small particle size of the filter material and biofilm flocculation can be used to intercept suspended solids in the sewage, so as to ensure that the detached biofilm will not float out with the water, which is the interception effect. After a period of operation, with the increase of head loss, the filter tank needs to be backwashed in order to release the trapped suspended matter and update the biofilm. This is the backflushing process. To be specific, firstly, the aerated biological filter should add a particle filter material with high specific surface area to the filter, which is conducive to the survival and growth of microorganisms. When to start operating aeration biological filter, sewage can flow from top to bottom or from bottom to top, and when the sewage flow through the filter filter, filter layer at the bottom of the blast blower also began to produce aeration, subsequently made in this process, air contact with sewage can reverse or higher, and the filter layer on the surface of the biofilm sublimation reaction with the organic pollutants in the water, degradation of organic pollutants, the effect is the premise of biological oxidation degradation reaction, and oxidation degradation can also effectively nitrification and denitrification, this makes the filtering process of secondary sedimentation can be omitted. In addition, the wastewater in the process of flow, particle filter material due to the smaller, biofilm on the surface of the creatures have flocculation effect, can produce separation effect, to ensure that the suspended pollutant in the sewage is separated, at the same time, the pollutants from the biofilm will be processed immediately, not into the water again, this process is to utilize intercept technology implementation. In the process of using the aerated biological filter, it is necessary to pay attention to the regular maintenance and repair.