What are the most common biological treatment methods for chemical wastewater?

1. Conventional activated sludge process. 2. A/O process (anoxic, aerobic). 3. A2/O (anaerobic, anoxic, aerobic) process.

Traditional activated sludge process, A/O process, A2/O process, A/B process, SBR process

Traditional push-flow activated sludge process, A/O, A2/O, SBR, oxidation ditch.

Contact oxidation, fully mixed type, PACT

Anaerobic processes include: IC, CECT, UASB, hydrolysis-acidification, etc

Wastewater is purified primarily by the decomposition of organic substances in it by microorganisms, converting them into simple inorganic compounds. 1. Based on their oxygen requirements, biological treatment can be divided into two main categories: anaerobic biological treatment and aerobic biological treatment. Anaerobic biological treatment makes use of anaerobic microorganisms to convert organic matter into organic acids, which are then broken down by methanogens into methane, carbon dioxide, hydrogen, etc.; examples include anaerobic lagoons, septic tanks, anaerobic digestion of sludge, and anaerobic bioreactors. Aerobic biological treatment utilizes mechanical aeration or natural aeration (such as oxygen production through algae photosynthesis) to provide the energy needed for aerobic microorganisms in wastewater to carry out their metabolic activities, thereby promoting their decomposition processes and enabling the purification of the wastewater. Examples of such methods include activated sludge systems, biological filters, biological rotors, wastewater irrigation, and oxidation ponds. 2. Based on the suspension state of microorganisms, they are divided into the activated sludge process and the biofilm process. In the activated sludge process, microorganisms are suspended in wastewater, such as in oxidation ditches, A2O, conventional activated sludge processes, SBR, and so on. In the biofilm process, microorganisms attach to carriers, such as in the biological rotating disk process and biological fluidized bed process.