When producing a single kind of resin, the concentration of COD cr can be reduced from 195 800 mg/ L to 57 000 mg/L by acid polycondensation or alkali polycondensation, and the removal rate is about 70%. Therefore, distillation pretreatment of resin wastewater can greatly reduce the concentration of pollutants. The concentration of organic matter in comprehensive wastewater is still high, and it contains a lot of toxic organic matter, which is difficult to biodegrade. According to the conventional biochemical treatment method, the number and activity of microorganisms that can degrade the target pollutants in the biochemical system are low, which affects the treatment effect. Even if the pretreatment process can reduce the COD cr concentration of wastewater to below 1 000 mg/ L, the COD cr concentration of biochemical effluent can only reach 300 ~ 400 mg/L. Since most toxic organic substances are degraded by * * * metabolism, adding some nutrients, including carbon sources and energy substances, will help to stimulate the growth of degrading bacteria, improve the operation performance of the treatment system and improve the biology of organic substances. Therefore, when the domestic sewage in the factory area is concentrated and mixed with the production wastewater, and a certain amount of special nutrients are properly added for blending, the biodegradability of the comprehensive wastewater can be improved, and at the same time, the targeted microbial flora can be cultivated during the biochemical treatment and debugging.
① Paint (coating) enterprises have great potential to control wastewater pollutants from the source, which can not only reduce pollutant emissions, but also improve product quality, fully embodying the idea of clean production.
② After distillation pretreatment, the concentration of COD cr in resin wastewater can be reduced from >: 100 000 mg/ L to about 55 000 mg/L, which greatly reduces the pollution load of subsequent biochemical treatment, and the distillate can be recycled.
(3) Using domestic sewage and special nutrients to mix industrial wastewater can greatly improve the biodegradability of wastewater. The operation experience shows that the COD cr concentration of wastewater before biochemical treatment is controlled at 1 200 ~ 1 800 mg/L, which can make the final effluent meet the standard stably.