基于一级动力学模型的潜流湿地污染物去除研究

摘要

通过对北京市野生动物救护中心水平潜流人工湿地运行特征参数及进出水水质情况进行定期连续监测,研究了污染物去除的面积速率常数及背景浓度与进水污染负荷之间的相关关系,并依据出水浓度,通过Arrhenius方程对潜流湿地不同污染物背景浓度进行了估计,同时分析比较了不同温度条件下污染物背景浓度的变化特征及不同背景浓度条件下面积速率常数的季节性变化规律.结果表明:污染物出水浓度与温度之间存在一定的相关关系,其中总悬浮固体物(TSS)和化学需氧量(CODcr)与温度的相关系数分别为0.6293和0.6210;对全磷(TP)和全氮(TN)的比较发现在估计背景浓度条件下,TP和TN的面积速率常数高于零背景值时的面积速率常数(P＜0.05),而CODcr和TSS的面积速率常数在零背景值和估计背景浓度下无显著差异(P＞0.05)；当污染负荷低于25mg/L时,潜流湿地对TSS去除的面积速率常数随迸水污染负荷的升高而呈指数增加,而在高污染负荷时,面积速率常数出现较大波动:污染物背景浓度与进水污染负荷之间存在一定的线性相关性,其中TSS的背景浓度与进水污染负荷之间的拟合度最高(R2=0.8388)；潜流湿地对污染物去除的面积速率常数存在较明显的季节性变化秋季面积速率常数较高,而夏季和冬季较低%Correlation analysis between the influent mass loading and the area rate constants, the influent mass loading and the background concentrations of different pollutants was conducted based on the datasets about the operating parameters and water quality obtained by continue monitoring the horizontal subsurface constructed wetland which located in Beijing Wildlife Rescue Center. The background concentrations were estimated through Arrhenius equation based on the effluent mass loading. The changing characteristics of the background concentrations at different temperatures and the seasonal variation of the area rate constants at different background concentrations were analyzed. The results showed that the effluent mass loading was correlated with temperature in a certain extent. The relationships between total suspended solids (TSS) and temperature, chemical oxygen demand (CODcr) and temperature were fitted well, with a higher coefficient of 0.6293 and 0.6210 respectively. Comparison of the total phosphorus (TP) and total nitrogen (TN) implied that the area rate constants calculated from the estimated background concentration were higher than those calculated from zero background concentration (P<0.05), but no significant differences between the area rate constants at different background concentrations were found both for CODCT and TSS (P>0.05). The area rate constant of TSS increased exponentially with the increasing of influent mass loading when the mass loading was lower than 25 mg/L, but changed greatly at a higher mass loading. Linear relationships were found between the background concentrations and influent mass loading. The relationship between the background concentration and influent mass loading was fitted well for TSS, with a higher coefficient of 0.8388. Appreciable seasonal variation existed on the area rate constants of different pollutants. The area rate constants were higher at autumn compared with those at summer and winter.