Removal efficiency and biotoxicity evaluation of iron-carbon micro-electrolysis process for coal pyrolysis wastewater pretreatment

In order to enhnace removal efficiency of refractory compounds and biodegradability of effluent,the iron-carbon micro-electrolysis process was used for coal pyrolysis wastewater pretreatment.The removal efficiency,biodegradability and biotoxicity of coal pyrolysis wastewater were studied in iron-carbon micro-electrolysis process.The results showed that the micro-electrolysis reaction performed high removal efficiency for coal pyrolysis wastewater at the condition of Fe-C filler content of 50 g/L and pH of 5,the corresponding COD and total phenol removal efficiency reached 51.87% and 54.32%,respectively.Meanwhile,micro-electrolysis could make massive refractory compounds be transformed into biodegradable compounds,and make B/C ratio increase to 0.41,thereby effectively improving biodegradability of coal pyrolysis wastewater.Additionally,micro-electrolysis significantly reduced biotoxicity and reduced the effluent acute toxic unite (TU) by about 65%.It was suggested that iron-carbon micro-electrolysis is an efficient and feasible method for coal pyrolysis wastewater pretreatment,which can provide good water quality conditions for the subsequent biological process and advanced treatment process.