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研究论文

Removal efficiency of typical pollutants by different substrate combinations for constructed wetlands

摘要：选取沸石、火山岩、空心砖、钢渣4种填料，通过对水中典型污染物的等温吸附试验，进行填料组合方式的优化配比.选取优化后的配比组合模拟人工湿地基质系统进行动态试验，进一步考察分析不同填料组合对污染物去除效果的差异.实验结果表明，Langmuir模型能够较好地模拟填料对氮、磷的吸附过程.各填料对NH₄⁺-N的饱和吸附量大小为沸石（2388.92 mg · kg^-1）>空心砖（618.39 mg · kg^-1）>火山岩（310.84 mg · kg^-1）；对磷的饱和吸附量大小为空心砖（3051.57 mg · kg^-1）>钢渣（2863.69 mg · kg^-1）>火山岩（1102.78 mg · kg^-1）>沸石（717.15 mg · kg^-1）.在动态试验中，不同的填料组合对污染物具有不同的去除效果.综合考虑各填料组合对污染物的去除，选取效果最优的填料组合为ZH11（沸石与空心砖质量比1：1混合），其对COD、NH₄⁺-N、NO₃^--N、TP的去除率分别达到62.40%、95.54%、59.82%和97.50%.

Abstract：Zeolite, volcanic rock, hollow brick debris and steel slag were selected as potential substrates in a constructed wetland. Firstly, the substrate combinations were optimized and combined according to adsorption isotherm tests. The combinations with satisfactory removal efficiencies were then investigated for dynamic tests of pollutant removal in simulated wetland substrate columns. The results showed that Langmuir equations were well fitted for describing the adsorption characteristics of all single substrates. The theoretical saturated adsorption capacity of ammonia nitrogen onto three substrates followed the order of zeolite (2388.92 mg · kg^-1) > hollow brick (618.39 mg · kg^-1) > volcanic rock (310.84 mg · kg^-1). The theoretical maximum adsorption capacities of phosphorous onto four substrates followed the order of hollow brick (3051.57 mg · kg^-1) > steel slag (2863.69 mg · kg^-1) > volcanic rock (1102.78 mg · kg^-1) > zeolite (717.15 mg · kg^-1). In dynamic experiments, the pollutant removal efficiency varied with the substrate combinations. The substrate combination with the best removal efficiency was ZH11 (zeolite: hollow brick 1 ：1). With ZH11, the removal rates of COD, NH₄⁺-N, NO₃^--N and TP could achieve 62.40%, 95.54%, 59.82% and 97.50%, respectively.