Study On Improvement Of Chlor-alkali Wastewater Treatment Process And Facilities

Chlor-alkali wastewater has the characteristics of high salinity,suspended solids,high CODcr concentration and poor biodegradability.If the wastewater from chlor-alkali chemical industry is discharged directly without strict treatment,it is bound to cause serious damage to the environment.Therefore,better wastewater Processing technology,chlor-alkali enterprises outside the drainage to achieve national standards is of great significance.This paper chooses Chongqing Changshou Chlor-Alkali Chemical Co.,Ltd.production wastewater as the research object.The company is a small chemical company,mainly in the production of caustic soda,liquid chlorine,PVC and other products.Wastewater produced in the process of production mainly includes chlor-alkali workshop production wastewater,PVC workshop production wastewater,boiler dust removal desulfurization wastewater and domestic wastewater.The main indicators of wastewater:pH 2⁶,CODcr 190 mg/L²40mg/L,SS 200³00mg/L,NH₃-N 45⁶0mg/L.Because the original wastewater treatment system has only simple neutralization and sedimentation,and the unreasonable pH control of the wastewater directly affects the effect of the back sedimentation,the PAC feeding amount and the stirring time of the coagulation reaction pool are not reasonable enough,and the biochemical treatment technology is not used,Therefore,chlor-alkali wastewater CODcr and ammonia nitrogen concentration higher.The results show that the optimum pH range of coagulation and sedimentation is 8-9,the optimal pH is 8,the dosage of PAC is 400mg/L,the dosage of PAM is 3mg/L,the precipitation time For 30min,stirring time is 30min.The best time to stay in the hydrolytic acidification stage is 5h.The best aeration time of aeration experiment is 5h.The overall experimental process results:SS removal rate of up to 94.1%,CODcr removal rate of up to 82.7%,ammonia nitrogen removal rate of up to 89.1%.In the actual wastewater treatment,the use of coagulation sedimentation-hydrolysis acidification-biological aerated filter combination of operating better.The results of sampling showed that the average concentration of effluent CODcr was50mg/L⁷0mg/L,the average concentration of SS was 13mg/L⁴0mg/L and the average concentration of ammonia nitrogen was 6mg/L¹0mg/L.Water quality is stable,and can meet the national emission standards.