A Novel Method for Removing Phosphorus from Agricultural Runoff and Sewage Effluent

Treatment of polluting discharges from abandoned mines is producing large quantities of ochre (mainly iron (III) oxides) for which no major end-use has yet been identified. At the same time, phosphorus pollution is a serious threat to the water environment in industrialised countries, causing eutrophication, algal blooms, fish kills and loss of water resources. Newcastle and Edinburgh Universities are currently conducting research to develop and test novel field-scale methods to use ochre for phosphorus removal from agricultural runoff and sewage effluent. Our laboratory experiments have demonstrated that ochre is an excellent adsorbent of phosphorus from solution (up to 30 g P kg -1 ). Phosphorus removal is unaffected by phosphorus form (total, inorganic, organic) and solution pH. Potential applications of ochre for phosphorus removal from agricultural runoff and sewage effluent are discussed, including treatment of agricultural drainage with ochre-filled filter and dosing units and ochre-filled reaction vessels for sewage effluent treatment.