Analysis of Degradation by Aerobic Recharge for Concentrated Leachate
Concentrated leachate obtained from landfill leachate by membrane separation was treated using technique of aerobic recharge. Variation of effluent COD, NH3-N and pH in concentrated leachate during aerobic recharge was studied. The impact of hydraulic loading on the removal rate of COD and NH3-N was investigated. The results indicate that, after passing through the three stages of rapid declining, smooth declining and stabilization, the variation of effluent COD of the concentrated leachate versus time maintains in the range of 900~2000 mg/L, and the corresponding removal rate is 88%~92%. The variation of effluent NH3-N versus time indicates a trend that it climbs up initially and then declines. The effluent NH3-N starts from 700 mg/L. After 35 days, it declines down to 18 mg/L and maintains in the range of 93%~99% with a corresponding removal rate up to 98%. Aerobic recharge reduces the build up of organic acids in the early stage. After 10 days, the pH value of the leachate maintains in the range between 7.5 and 9.0. The COD removal rate decreases from 94.39% down to 75.75% when the hydraulic loading increases from 12.5 mL / (L·d) to 75mL / (L·d), indicating a strong trend. In the mean time, the NH3-N removal rate decreases from 98.14% down to 90.11%, indicating a weak tread.