◆Process introduction

The main feature of detergent wastewater is that the main pollutant in the wastewater is the anionic surfactant LAS. The high concentration of LAS in the wastewater has a certain hindering effect on the activity and proliferation of microbial cells. Therefore, it is more difficult to biodegrade this type of wastewater. The wastewater is alkaline, and the pH value is usually 9-12. In addition, the wastewater lacks the nitrogen element necessary for the synthesis of cytoplasm by microorganisms. According to the characteristics of this type of wastewater, a process flow combining physical and chemical treatment is determined. The physical and chemical treatment adopts coagulation sedimentation, and the biochemical treatment adopts hydrolytic acidification and contact oxidation.

After entering the anaerobic tank (hydrolysis acidification tank), the dissolved organic matter is absorbed by the microbial cells, which reduces the BOD concentration in the sewage; in addition, part of the NH3-N is removed due to the synthesis of the cells, which reduces the NH3-N concentration in the sewage. The NO3-N content did not change.

In the aerobic tank, the organic matter is biochemically degraded by microorganisms, and continues to decline; organic nitrogen is ammonified and then nitrified, so that the concentration of NH3-N decreases significantly, but as the nitrification process increases the concentration of NO3-N, P increases with The excessive intake of phosphorus bacteria also declined at a faster rate. Therefore, the A2/0 process can simultaneously complete the functions of organic matter removal, nitrification and denitrification, and removal of excessive phosphorus intake. The prerequisite for denitrification is that NH3-N should be fully nitrified. The aerobic pool can complete this function. The oxygen pool completes the denitrification function. The anaerobic tank and aerobic tank jointly complete the phosphorus removal function.