电化学氧化与厌氧技术联用处理垃圾渗沥水

采用电化学氧化与上流式厌氧污泥床(UASB)结合技术,提出了处理香港垃圾渗沥水的二步法工艺.对含COD和NH₃-N分别为4750mg/L和1310mg/L的垃圾渗沥水,首先进行UASB预处理(消化温度37℃,COD负荷0.78g/(L·d),HRT为6.1d),获得了66%的COD去除率;UASB的出水被引入电化学氧化反应器进行深度处理.在外加Cl 2000mg/L,电流密度为32.3mA/cm²的条件下,经6h的电解间接氧化,COD和NH₃-N的去除率分别达到87%和100%,出水的COD为209mg/L,并且不含NH3-N,此过程的COD电能消耗＜55kW·h/kg.本文讨论了电化学氧化过程中电极反应原理,各实验参数对COD和NH₃-N去除率的影响,以及电能消耗与运行成本评估等.

Landfill Leachate Treatment by Anaerobic Process and Electrochemical Oxidation

This study was conducted to develop a two-stage process of UASB and electrochemical oxidation for the treatment of Hong Kong leachate. The leachate, containing 4750 mg/L of chemical oxygen demand (COD) and 1310 mg/L of ammoniacal nitrogen (NH3-N), was first treated in a UASB (upflow anaerobic sludge blanket) reactor at 37 degrees C. The process removed on average 66% of COD with 6.1 days of hydraulic retention time (HRT), corresponding to an organic loading rate COD of 0.78 g/(L.d). The UASB effluent, which had an average pH of 8.9, COD of 1610 mg/L and NH3-N of 1480 mg/L, was then further treated by electrochemical oxidation in a batch reactor with recirculation. With the addition of 2000 mg/L of chloride (in the form of sodium chloride) and at a current density of 32.3 mA/cm2, 87% of COD and 100% of NH3-N were removed from the UASB effluent in six hours. The energy consumption was < 55 kW.h/kg COD. The final effluent contained no residual NH3-N and only 209 mg/L of COD. In this paper, some basic problems in electrochemical oxidation, such as the effects of the operation parameters, the mechanism of the process, and assessment of the energy requirements were discussed in detail.