Study On The Treatment Of The Organic Wastewater From PCB Production By Acidification-Fenton-Coagulation

With the development of PCB (printed circuit board) industry, the production wastewater treatment had been a difficult and urgent problem. The organic wastewater, which mainly including stripping and development wastewater, was hard to be discharged up to the standard by traditional biological and physical-chemical processes. Combined treatment process was a studying direction of industrial wastewater treatment technology.The combined process of Acidification-Fenton oxidation–Coagulation was employed in the study of wastewater treatment, which water sample taken from Yintian industrial zone in Shenzhen city. Firstly, in order to achieving the best treatment effect and reducing cost, the optimal technological conditions of Fenton oxidation and coagulation were ascertained by single factor experiments; then the optimal pH of pre-acidification was determined by experiment according to characteristics of stripping and development wastewater; next, study on kinetics of organic degradation by Fenton reagent was conducted; after that, under the optimal conditions respectively, wastewater was treated by process A of acidification-coagulation-Fenton and process B of acidification -Fenton-Coagulation. The comparison results of A and B treatment effect showed that effluent COD could be significantly reduced by two both of process. The total COD removal rate of process A was 90%, process B was 94%.COD value of effluent was 76mgL-1 for A and 46mgL-1 for B. Treatment effect by A was better than B obviously. The water turbidity was reduced by B remarkably from 619NTU to 3NTU, removal rate of turbidity was up to 99.5%. The COD removal rates were significantly decreased in coagulation and Fenton oxidation stage respectively than the period of single factor experiments. The reason was that COD was decreased largely after acidification treatment, only less than 200mgL-1. Finally,The economic cost analysis of the two treatment methods was conducted. The result showed that comparing with method A , method B not only saved the cost of 9% for lacking of one adding acid step, but also reduced labor force and time cost .The pH values of acidification, Fenton and coagulation were different in this paper; the prior procedure should prepared for the following process. It would reduce the cost of wastewater treatment, acid wastewater would be reclaimed as spent acid to acidification.This research provided a valuable reference for the generalization and application of this technique and had a certain practical significance for the more and more serious problem of wastewater pollution.