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Pollutants removal in subsurface constructed wetland based on the first-order kinetic model |
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Abstract 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 (P0.05). 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.
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Received: 28 January 2011
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