Pretreatment of Oil Shale Retort Wastewater by Acidification and Ferric-Carbon Micro-Electrolysis

The combined process of acidification and ferric-carbon micro-electrolysis was used to pre-treat oil shale retort wastewater. The influence factors, such as optimum acidized condition, ferrous-carbon ratio, pH value and reaction time were investigated. The results showed:in the acidification process,the optimum oil shale retort wastewater acidized conditions were pH value 4.0 and sediment 24 h, the content of mineral oils was 1670 mg/L, and its removal rate was 61.52%; the content of CODcr is 7400 mg/L, and its removal rate was 28.85%; the content of volatile phenol was 891.17 mg/L, and its removal rate was 17.03%. In the ferric-carbon micro-electrolysis process, the treatment effect of ferric-carbon micro-electrolysis was the best with ferrous-carbon ratio 5:8, pH value 5.0, reaction time 60 min and sediment 2 h. After the combined pretreatment of acidification and ferric-carbon micro-electrolysis, the content of CODcr was 1600 mg/L, and its removal rate was 78.38%, the content of phenol was 21 mg/L, and its removal rate was 97.64%, the content of colority was 697.32 degree, and its removal rate was 79.68%. At the same time, the BOD/COD value of wastewater increased from 0.05 to 0.34 that fully showed the improvement of biochemical property.