Study On The Treatment Of Epichlorohydrin Wastewater By Electrodialysis-biological Process

The wastewater which is produced during the production process ofepichlorohydrin (ECH) has high alkalinity, high concentrations of inorganic salt，andit also contains organic chlorides. The treatment of ECH wastewater now becomesone of the difficulties and hot research topics in the researchers at home and abroad.At present, the biological method is the conventional way which is most widely usedto deal with the ECH wastewater, but the high salinity in the ECH wastewater is theobstacle, so it makes the treatment difficult and the result is bad.In this study, the electrodialysis-biological method was adopted to deal with theECH wastewater, which was with high salinity, intended to provide a new process forthe effective treatment of analogous wastewater with high salinity. Firstly,polyaluminium chloride (PAC) was used as the flocculants to deal with the ECHwastewater, the research studied the factors which affected the results during theflocculation precipitation process, and obtained the optimum pH and the appropriatetemperature in the flocculation precipitation process of ECH wastewater, at22℃, pHof8and polyaluminium chloride as the flocculants, the removal rate of CODCrreached about40%. The wastewater was further put into the electrodialyzer, theinfluence of operating conditions on desalination rate was explored, and the change ofsalinity and CODCrwere studied, obtaining the desalination rate changing with theoperating conditions during the electrodialysis process. By replacing draw solutionwith deionized water many times,90%of salinity in the ECH wastewater wasremoved. During the electrodialysis process, the CODCrof wastewater went downgradually, but lightly.Then municipal sludge was cultivated and domesticated, and it was used to treatthe desalinated wastewater. The CODCrof wastewater was studied with the operatingconditions. And under the optimal conditions, the desalinated wastewater was treatedby the biological process. When pH was8, temperature was30℃and dissolvedoxygen concentration was3mg/L in the sludge tank, after6h’s treatment ofdesalinated wastewater, the CODCrof wastewater was less than100mg/L, while theCODCrof wastewater without desalination dropped to the minimum of400mg/L after12h’s biological treatment. The experimental results show that the electrodialysis-biological process isfeasible to deal with the ECH wastewater, the study provides a basis for the practicalindustrial application.