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United States Department of Agriculture

Agricultural Research Service

Research Project: Conservation Practice Impacts on Water Quality at Field and Watershed Scales

Location: National Soil Erosion Research

Title: A review of phosphorus removal structures: How to assess and compare their performance

Author
item Penn, Chad
item Chagas, Isis
item Klimeski, Aleksanders
item Lyngsie, Gry

Submitted to: Water
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2017
Publication Date: 8/10/2017
Citation: Penn, C.J., Chagas, I., Klimeski, A., Lyngsie, G. 2017. A review of phosphorus removal structures: How to assess and compare their performance. Water. 9(8):583.

Interpretive Summary: Phosphorus (P) losses to surface waters are the main culprit in algae blooms and eutrophication. Preventing particulate P transport is relatively easy, but dissolved P losses are much more difficult to control. The P-removal structure, a large landscape-scale filter, was developed to filter dissolved P from drainage water before reaching a lake or stream. Filter materials known as P sorption materials (PSMs) are often industrial by-products, and greatly vary with regard to their ability to remove P. This paper presents a method for normalizing P removal data that allows for comparison between different PSMs and studies. The performance of a PSM will also vary as a function of the inflow P concentration and the time in which the water is in contact with the PSM (retention time, RT). Second, this paper summarizes the performance of over 40 studies conducted on pilot or full-scale P removal structures, and compares their performance. Structures treating wastewater were more efficient compared to those that treated non-point drainage water due to higher inflow P concentrations and longer RT for wastewater. The PSMs dominated with calcium and increased RT would result in an increased cumulative P removal. For non-point drainage structures, which typically have low inflow P concentrations and RT, the iron-based PSMs were more efficient at P removal compared to the Ca-based PSMs. The average cumulative P removal for all studies was 33%. The summarized information from field installed P removal structures is useful to those who plan to construct similar systems.

Technical Abstract: Controlling dissolved phosphorus (P) losses to surface waters is challenging as most conservation practices are only effective at preventing particulate P losses. As a result, P removal structures were developed to filter dissolved P from drainage water before reaching a water body. While many P removal structures with different P sorption materials (PSMs) have been constructed over the past two decades, there remains a need to evaluate their performances and compare on a normalized basis. The purpose of this review was to compile performance data of pilot and field-scale P removal structures and present techniques for normalization and comparison. Over 40 studies were normalized by expressing cumulative P removal as a function of cumulative P loading to the contained PSM. Results were further analyzed as a function of retention time (RT), inflow P concentration, and type of PSM. Structures treating wastewater were generally more efficient than non-point drainage water due to higher RT and inflow P concentrations. For Ca-rich PSMs, including slag, increased RT allowed for greater P removal. Among structures with low RT and inflow P concentrations common to non-point drainage, Fe-based materials had an overall higher cumulative removal efficiency compared to non-slag and slag materials.

Last Modified: 09/22/2017
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