Wastewater Treatment Of Fine Chemicals Industrial By UASB

This project comes from the improvement of wastewater treatment process in a fine chemical company in Dalian. For business reasons, the original physical chemistry-contact oxidation process can not meet the standard of COD<300 mg/L because the discharge of wastewater increased from 200 T/d to 400 t/d. The wastewater is complicated in composition with high concentration of organics which will impact downstream wastewater treatment plant without any promptly pre-treatment.Based on the evaluation, we decided to keep the original aerobic unit using contact oxidation process. A anaerobic device should be added in fore-end and keep stable effluent flow to ensure back-end discharge water to meet national standard. The COD can controlled between 1100 mg/L and 1500 mg/L.We take raw wastewater from target company and build UASB reactor at the same time. The main research contents are as follows.(1) Acclimate residue downstream wastewater treatment plant sludge particles to adapt target company wastewater circumstance.(2) Evaluation of acclimated sludge particles capacity.(3) Study on the main COD index factors affecting the of water quality.(4) Determining the feasibility of using UASB in target company.The results showed that:(1) The start time of UASB has been shortened by using the acclimated residue sludge particles from downstream wastewater treatment plant. The acclimation cost only three months.(2) The most adaptive operating parameters are found:Hydraulic retention time (HRT):24 hours, Temperature:35?, Basicity:1000 mg/L-1200 mg/L, pH value 7-8, Influent COD concentration:4000 mg/L-6000 mg/L.(3) UASB is proved feasible to target company which can provide a stable water quality for the subsequent aerobic process. The COD of effluent:1100 mg/L-1500 mg/L.