沉水植物型生态净化系统处理农田退水的总磷去除动力学研究

Kinetic modeling of total phosphorus removal from farmland drainage with submerged macrophyte-type ecological purification system

【目的】探讨以沉水植物为先锋物种的生态净化系统处理农田退水磷污染的动力学性能。【方法】通过批式试验研究苦草Vallisneria natans和金鱼藻Ceratophyllum demersum等2种沉水植物型净化系统对农田退水总磷的净化效率及其动力学特征。【结果】至试验结束时(第49天),2种植物净化系统总磷去除效率无显著差异(P>0.05),总磷去除率分别为82.8%(苦草型)和84.0%(金鱼藻型),但两者总磷去除效率的差异在时间尺度上存在不确定性;动力学模拟分析发现:除Grau二级动力学外,一级动力学、Monod动力学和修正的Gompertz模型均可以描述试验条件下总磷的去除过程[判定系数(R2)>0.930,相对均方根误差(RRMSE)<0.200],其中Monod动力学和Gompertz模型具有更高的拟合度(R^(2)>0.970),预测值与实验观测值之间吻合程度更好(RRMSE<0.110)。【结论】3种有效模型拟合获得的动力学常数在植物种类水平上均存在显著差异(P<0.05),其中指示总磷去除效率的动力学常数值一致表现为苦草型>金鱼藻型,表明苦草型净化系统除磷效率好于金鱼藻型。图5表2参35。

[Objective]The objective of this study is to investigate the dynamic performance of ecological purification system with submerged macrophytes as pioneer species for treatment of phosphorus pollution in farmland drainage.[Method]A batch-mode mesocosm experiment was performed to study total phosphorus(TP)purification efficiency and kinetic parameters of two submerged macrophyte systems:Vallisneria natans and Ceratophyllum demersum.Four kinetic models including first-order kinetic,Grau second-order kinetic,Monod kinetic and modified Gompertz model were used to evaluate TP removal efficiency.[Result]At the end of the experiment(Day 49),there was no significant difference in TP removal efficiency between the two mesocosm systems(P>0.05),and the TP removal rates were 82.8% for V.natans and 84.0% for C.demersum,but the difference in TP removal efficiency was uncertain in time scale.Kinetic simulation analysis showed that except Grau second-order kinetic,first-order kinetic,Monod kinetic and modified Gompertz model were proven capable of predicting TP removal process of the two submerged plant systems under experimental conditions,with R^(2)(coefficient of determination)>0.930 and RRMSE(relative root mean square error)<0.200.Among them,Monod kinetic and modified Gompertz model showed a higher fitting degree(R2>0.970),and a better agreement between the predicted value and the observed value(RRMSE<0.110).[Conclusion]The kinetic parameters obtained by the three effective model fitting show significant differences at the plant species level(P<0.05),and V.natans has higher kinetic parameter of TP removal efficiency compared with C.demersum(P<0.05),indicating that TP removal efficiency of V.natans is better than that of C.demersum.[Ch,5 fig.2 tab.35 ref.]