Crushed concrete as a phosphate binding material: a potential new management tool
Sara Egemose1, Melanie J Sønderup, Malde V Beinthin
1Institute of Biology, Univ. of Southern Denmark, Odense. saege@biology.sdu.dk
Journal of Environmental Quality
|May 9, 2012
Summary
Crushed concrete effectively removes phosphorus (P) from runoff, acting as a sustainable filter material. This method is viable for urban and agricultural applications, but requires pH neutralization before water discharge.
Area of Science:
- Environmental Science
- Water Treatment Technology
- Materials Science
Background:
- Eutrophication from phosphorus (P) runoff necessitates effective removal methods.
- Urban and agricultural runoff contribute significantly to water body P loading.
- Dissolved and particulate P removal requires innovative and sustainable solutions.
Purpose of the Study:
- To evaluate crushed concrete as a filter material for P removal.
- To quantify P retention capacity of different concrete types.
- To assess factors influencing P removal efficiency and potential drawbacks.
Main Methods:
- Laboratory testing of five crushed concrete types for dissolved P retention.
- Analysis of P release from bound forms.
- Column experiments to simulate runoff conditions.
- Assessment of heavy metal leaching.
Main Results:
- All concrete types demonstrated high P retention (5.1-19.6 g P kg(-1)).
- P retention increased with finer concrete grain size and higher pH (up to pH 12).
- Outlet P concentrations were <0.0075 mg P L(-1) under optimal conditions.
- Heavy metal release was negligible.
Conclusions:
- Crushed concrete is a highly effective P removal agent for runoff.
- Optimal performance is linked to fine particle size and high pH.
- Neutralization or dilution of high pH effluent is crucial before discharge to prevent adverse effects.
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