[1]QIAO Sha,ZHENG Xueliang.Experimental Study on the City Runoff Pollutant Reduction by Multi-Series Surface Flow Constructed Wetland[J].Research of Soil and Water Conservation,2019,26(03):353-361.
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Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
26
Number of periods:
2019 03
Page number:
353-361
Column:
Public date:
2019-04-12
- Title:
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Experimental Study on the City Runoff Pollutant Reduction by Multi-Series Surface Flow Constructed Wetland
- Author(s):
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QIAO Sha1, ZHENG Xueliang2
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1. China Forest International Engineering Consulting Co., Ltd., Beijing 100013, China;
2. School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
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- Keywords:
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constructed wetland; surface flow; city; runoff; purification effect
- CLC:
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X524
- DOI:
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- Abstract:
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Rural domestic sewage has become one of the main sources of agricultural non-point source pollution. According to water characteristics of the runoff in Wuhan City, multi-series surface flow constructed wetland was used for purification experiment study on simulated and on-the-spot runoff. The purification effects of simulated runoff were compared in different operated phases of multi-series surface flow constructed wetland. Meanwhile, the variation of the pollutants (CODCr, SS, TN, TP, NH4+-N) along the constructed wetland and their removal mechanism were analyzed and discussed, respectively. In the purification study of on-the-spot runoff, removal rates of CODCr, SS, TN, TP, NH4+-N decreased in the order:NH4+-N > CODCr > BOD5 > TN > SS > TP in which the effluent met the grade Ⅲ of water. In the simulated experiment, the effluent water quality of BCW system met the needs of Environmental Quality Standard for Surface Water (GB 3838-2002) Ⅲ, besides TN met Ⅳ, most of the pollutants were removed in the front of the constructed wetland. The removal rate gradually decreased with the units. Correlation analysis showed that TP had no significant difference with the other pollution parameters (p>0.05). We established the exponential, the linear, and the quadratic polynomial model which were related to the inlet concentration of the wetland system through the monadic linear regression analysis of model coefficients. Then these three models were used for prediction and evaluation on the basis of the other four groups of testing data. Correlation analysis revealed that exponential decay model had a smaller relative root-square-error value with the best performance. The wetland system showed good purification effect during the whole test period, reducing the discharge of nitrogen and phosphorus of rural domestic sewage greatly, and mitigating the damage of domestic sewage to freshwater environment. The establishment of exponential attenuation model provided reference for the prediction of concentration changing along the multistage tandem constructed wetland system. The model can be used to easily predict nutrient concentration in any wetland subsystem when the influent concentration of the system is known. In total, there was remarkable treatment performance of the runoff when constructed wetland system was used, which also can withstand strong shock load. Moreover, it can be used to control urban surface runoff pollution.