Wang Fangze, Ye Chengze, Wang Jiayi, Xu Xiangyang
ZJU-UIUC Institute, Zhejiang University, Haining, People's Republic of China.
College of Environmental & Resource Sciences, Zhejiang University, Hangzhou, People's Republic of China.
Environ Technol. 2025 Aug;46(19):3904-3917. doi: 10.1080/09593330.2025.2480320. Epub 2025 Mar 27.
Aged landfill leachate is a type of refractory wastewater containing high concentrations of humic substances and ammonia nitrogen (NH-N). A new three-dimensional electrocatalytic oxidation (3D-ECO) system was constructed to treat aged leachate using a composite-loaded metal electrode as the anode, a titanium plate as the cathode, and coconut shell biochar (CBC) as particle electrodes. The conditions for the electrochemical reaction were first optimized, and the pollutant removal effects of the two-dimensional (2D) and 3D systems were compared under optimal conditions. Finally, the electrochemical degradation mechanism was analysed. The results showed that when the initial pH was 5, the current density was 30 mA/cm², the particle addition was 7 g/L, and the electrode plate spacing was 4 cm, the pollutant removal efficiency in the leachate was the highest. At then the removal rates of COD and NH-N were 90.2% and 30.4%, respectively, while under the same conditions, they in the 2D system were only 41.1% and 17.4%, respectively. The introduction of CBC has increased the removal rate of organic pollutants in leachate by 49.1% and reduced energy consumption by 57.2%. Various active substances such as hydrogen peroxide, hydroxyl radicals, and singlet oxygen played a major role in the degradation of leachate pollutants. The synergy between the anode and the third electrode (75%) enhanced the overall effect of electrochemical degradation of organic pollutants in leachate. Therefore, the introduction of CBC can effectively improve the level of pollutant removal, and the 3D-ECO process is a promising technology for treating aged landfill leachate.
老龄垃圾渗滤液是一种含有高浓度腐殖质和氨氮（NH-N）的难处理废水。构建了一种新型三维电催化氧化（3D-ECO）系统，以复合负载金属电极作为阳极、钛板作为阴极、椰壳生物炭（CBC）作为粒子电极来处理老龄渗滤液。首先优化了电化学反应条件，并在最佳条件下比较了二维（2D）和3D系统的污染物去除效果。最后分析了电化学降解机理。结果表明，当初始pH为5、电流密度为30 mA/cm²、粒子添加量为7 g/L、电极板间距为4 cm时，渗滤液中污染物去除效率最高。此时，COD和NH-N的去除率分别为90.2%和30.4%，而在相同条件下，2D系统中的去除率分别仅为41.1%和17.4%。CBC的引入使渗滤液中有机污染物的去除率提高了49.1%，能耗降低了57.2%。过氧化氢、羟基自由基和单线态氧等各种活性物质在渗滤液污染物降解中起主要作用。阳极与第三电极之间的协同作用（75%）增强了渗滤液中有机污染物电化学降解的整体效果。因此，CBC的引入可有效提高污染物去除水平，3D-ECO工艺是处理老龄垃圾渗滤液的一种有前景的技术。
