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| Retention effect of ecomedium on nitrogen and phosphorus of agricultural nonpoint source pollution |
| (1. School of Environmental and Safety Engineering, Jiangsu University， Zhenjiang，
Jiangsu 212013， China; 2. Waterworks Corp of Zhenjiang, Zhenjiang， Jiangsu 212000，
China) |
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Abstract Ecomedium device with layered medium was used to remove nitrogen (N) and
phosphorus (P) of agricultural nonpoint source pollution (NPS) caused by rainfall
runoff. The experiment results indicate that the system has significant removal efficiency
of N and P. In the simulation of rainfall runoff formation under different rainfall
intensity running for 0.5 h, 1 h and 3 h, the removal rates of TN are 44.63% to 62.36%,
38.59% to 54.74% and 29.69% to 51.94%, and the removal rates of TP are 67.20% to 88.36%,
56.08% to 81.48% and 38.62% to 70.37%, respectively. The mass concentration of dissolved
oxygen (DO) at the vertical direction is 0.23 to 5.61 mg·L-1 to provide ideal environment
for microbial nitrificationdenitrification.NH4+N removal is mainly completed by
adsorption and microbiological nitrification in the layer of zeolite and ceramic.TN
removal is pushed by denitrification in the middle and lower unit. TP removal is achieved
by precipitation reaction of phosphate and metal elements in the limestone layer.
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Received: 18 November 2015
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2016, Vol. 37 
