室内中试人工湿地无植物填料床去污性能研究

Pollutant Removal of Indoor Unplanted Substrate Beds

完成人工湿地填料筛选后,为进一步确定无植物条件下人工湿地填料床去污性能,在柱状填料去污实验结果的基础上进行室内中试实验。中试实验装置包括污水配给箱、无植物填料床(有机玻璃材质,长×宽×高=3 m×1 m×1.5 m)、出水池和电磁流量计等。装置内填充页岩、粗砾石、麦饭石构建无植物填料床,研究无植物条件下湿地填料的COD、TN、TP去除效果。实验结果表明,当水力负荷为400 mm.d-1时,页岩和麦饭石为主填料层的1#COD、TN、TP最高去除率分别为15%、33%和60%,单一页岩为主填料层的2#COD、TN和TP去除率稍高于1#,分别为20%、38%和69%,湿地填料对污染物质去除贡献较小。为确定污染物质去除之间的相关关系,将COD、TN、TP去除率进行相关性分析,发现COD去除与TP去除呈正相关关系,COD去除与TN去除、TN去除与TP去除呈负相关关系。

After selection of constructed wetland substrates, an indoor pilot experiment was conducted to investigate pollutant removal performance of unplanted substrate beds based on the results of column experiments. Experimental apparatus consisted of wastewater feeding tank, unplanted substrate beds, effluent tank and electromagnetic flowmeter etc. Shale, coarse gravel and hornblende were packed into organic grass apparatus （with a dimension of 3 m × 1 m × 1.5 m）. In this experiment, hydraulic loading rate was equal to 400 mm · d^-1, we found that maximal COD, TN and TP removal rates were 15% , 33% and 60% , respectively, for 1# （ shale and hornblende used as main substrate layers）. During a same period of the test run, the maximal COD, TN and TP removal rates were 20% , 38% and 69% , respectively, for 2# （ single shale used as the main substrate layers） , revealing that these values were somewhat higher than those for 1#. Such low COD, TN and TP removal rates indicated that substrates contributed less to pollutant removal of unplanted substrate beds. In order to reveal a relationships between different pollutant removals, COD, TN and TP removal rates were analyzed by linear regression model. It was found that there was a positive correlation between COD removal and TP removal, while COD removal and TN removal, TN removal and TP removal showed negative correlations.