Journal of Ecology and Rural Environment ›› 2016, Vol. 32 ›› Issue (4): 639-644.doi: 10.11934/j.issn.1673-4831.2016.04.019

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Translocation and Transformation of Phosphorus in Rainwater Runoff in the Bio-Retention System

FENG Cui-min1, CAI Zhi-wen1, MI Nan2, ZHANG Ya-jun1, QIAN Hong-liang3   

  1. 1. Key Laboratory of Urban Stormwater System & Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China;
    2. China Mobile Group Design Institute Co. Ltd., Beijing 100080, China;
    3. Beijing General Municipal Engineering Design & Research Institute Co. Ltd., Beijing 100082, China
  • Received:2016-02-25 Online:2016-07-25 Published:2016-07-26

Abstract:

Based on effects of a bio-retention system on rainwater, a simulation test on rainwater runoff was carried out. With the sequential extraction method, contents of exchangeable inorganic phosphorus(Ex-P), aluminum phosphate(Al-P) and iron phosphorus(Fe-P) in the filtration medium or soil of the bioretention system at different depth (0, 5, 15 and 35 cm) were determined and TP in the effluent of bio-retention system was also monitored. Results show that the adsorption of Ex-P, Al-P and Fe-P by the soil medium decreased with the depth, layer by layer from the top to the bottom. During the process of adsorption, Ex-P gradually transformed into Al-P and Fe-P, while, Al-P did into Fe-P. As a result, Ex-P decreased in concentration while Al-P and Fe-P increased with the depth. About 90% of the TP in the runoff rainwater was intercepted and removed by the system. The phosphorus, not absorbed by plants, remained in the system, being a part of the dynamic TP balance of the water-soil-root-biome system.

Key words: bio-retention, soil filtration medium, runoff rainwater, phosphorus, translocation, transformation

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