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Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
A laboratory study to determine the use of polluted river sediment as a substrate for extensive green roofs
Wei Zhang1, Xing Zhong2, Wu Che1
1Beijing Engineering Research Center of Sustainable Urban Sewage System Construction and Risk Control, Beijing University of Civil Engineering and Architecture, 100044 Beijing, China E-mail: zhangwei@bucea.edu.cn; Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China and Beijing Advanced Innovation Center for Future Urban Design, 100044 Beijing, China.
Abstract:
In this study, laboratory-scale green (e.g. living) roof platforms were established to assess the potential use of polluted river sediment in their substrate mixture. The mean runoff retention of the green roof platforms, which contained peat and/or river sediment, after 11 artificial rainfall events was >72%, significantly higher than traditional roofs. However, green roof platforms that had been filled with peat soil showed chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) leaching. Green roofs that had used river sediment showed good leaching control for COD, TN and TP. The cumulative leaching masses from the green roofs contained 30% (COD), 42% (TN) and 47% (TP) as much as the total leaching mass from traditional roofs, and the Cu, Zn, Cd and Pb leaching risk from green roofs when river sediments are used as part of a substrate mixture was relatively low. Despite some nutrient leaching in the initial phase of runoff from the green roofs, river sediment has the potential to be used as a substrate for extensive green roofs.
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