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Environ Technol. 2018 Jul;39(13):1715-1720. doi: 10.1080/09593330.2017.1337233. Epub 2017 Jun 14.

Nitrogen and phosphorus removed from a subsurface flow multi-stage filtration system purifying agricultural runoff.

Zhao Y1,2, Huang L1,2, Chen Y1,2.

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a Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment (Ministry of Education), College of Resource and Environment , Southwest University , Chongqing , People's Republic of China.
b Chongqing Key Laboratory of Agricultural Resources and Environment , Chongqing , People's Republic of China.


Agricultural nonpoint source pollution has been increasingly serious in China since the 1990s. The main causes were excessive inputs of nitrogen fertilizer and pesticides. A multi-stage filtration system was built to test the purification efficiencies and removal characteristics of nitrogen and phosphorus when treating agricultural runoff. Simulated runoff pollution was prepared by using river water as source water based on the monitoring of local agricultural runoff. Experimental study had been performed from September to November 2013, adopting 12 h for flooding and 12 h for drying. The results showed that the system was made adaptive to variation of inflow quality and quantity, and had good removal for dissolved total nitrogen, total nitrogen, dissolved total phosphorus (DTP), and total phosphorus, and the average removal rate was 27%, 36%, 32%, and 48%, respectively. Except nitrate ([Formula: see text]), other forms of nitrogen and phosphorus all decreased with the increase of stages. Nitrogen was removed mainly in particle form the first stage, and mostly removed in dissolved form the second and third stage. Phosphorus was removed mainly in particulate during the first two stages, but the removal of particulate phosphorus and DTP were almost the same in the last stage. An approximate logarithmic relationship between removal loading and influent loading to nitrogen and phosphorus was noted in the experimental system, and the correlation coefficient was 0.78-0.94.


[Formula: see text]: ammonium; [Formula: see text]: nitrite; [Formula: see text]: nitrate; DTN: dissolved total nitrogen; TN: total nitrogen; DTP: dissolved total phosphorus; TP: total phosphorus; PN: particulate nitrogen; PP: particulate phosphorus.


Agricultural runoff; loading; multi-stage filtration system; nitrogen; phosphorus

[Indexed for MEDLINE]

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