What factors affect the concentration of COD in sewage?

With the rapid development of industry and the rapid improvement of living standards, the sources of sewage appear to be very extensive and various. So, what are the main factors that affect COD in sewage?

1. Changes in the oxygen supply environment

        The sludge produced in the secondary sedimentation tank mainly comes from the biofilm after shedding. Since the biofilm is mainly composed of aerobic bacteria, it is converted from aerobic to anaerobic in the oxygen supply environment. A large number of aerobic bacteria are ruptured and the cytoplasm is dissolved. Part of it is used by facultative bacteria and anaerobic bacteria to synthesize bacteria, and part of it enters the water body to become undegraded COD. At the same time, the broken aerobic cell wall fragments cannot be decomposed by facultative bacteria and anaerobic bacteria, and become refractory organic matter suspended in the water body. Due to the existence of a large amount of sludge, the COD in the secondary sedimentation tank does not drop but rises.

2, its own factors       

 The COD of wastewater produced in the production of enterprises will be too high, such as residues in food factories, pickling wastewater in electroplating industry, and reducing substances in chemical plants, etc., which will lead to excessive COD.

3. the process is not perfect

        When the temperature and dissolved oxygen in the sewage are too low, the activity of the bacteria in the sewage decreases, and normal metabolism cannot be achieved, so that the COD in the sewage cannot be decomposed normally. Once the COD concentration in the sewage is too high, it will poison the biochemical industry After the bacteria in the pool are destroyed, the COD concentration will rise, thus entering an infinite vicious circle.

4. How to reduce COD in sewage?

        Usually, the process is improved to increase the bacterial species in the biochemical pool. Although this method can effectively reduce the COD value in the water, the transformation process needs to be stopped and the cost will be high. Therefore, in order to save costs on the premise of convenient and effective removal of COD, we recommend that you use a COD degrader, which is easy to operate and can be directly added without equipment. It can reach the standard discharge in 6 minutes, and will not produce secondary pollution.