Drainage losses of phosphorus (P) contribute to an estimated load of 33% of total agricultural P losses in Denmark. Mitigating agricultural P losses is challenging, as critical P losses are only a small fraction of actual soil P contents and not directly related to fertilizer P input. Targeting high risks areas of P loss and applying site-specific measures therefore seems a more cost-efficient approach. The Danish Commission for Nature and Agriculture has now called for a shift of paradigm towards targeted mitigation and development of new, cost-efficient technologies to mitigate site-specific nutrient losses in drainage. The “SUPREME-TECH” project (2010-2015), funded by the Danish Strategic Research Council, aims at providing the scientific basis for developing cost-effective drainage filter technologies to retain P in agricultural drainage waters. The project studies different approaches of implementing the drainage filter technologies including surface-flow constructed wetlands, subsurface flow constructed wetlands, and drainage well filters (www.supremetech.dk). We will present results on P retention from (i) controlled column experiments with permeable filter substrates, and (ii) a full-scale surface-flow constructed wetland. In the former, various natural and industrial P filter substrates have been tested for their ability to reduce inlet P concentrations to below environmental threshold values (<0.05 mg P L-1) at variable phosphorus loads, hydraulic retention times, and flow regimes. Based on laboratory experiments and field scale monitoring, the different filter technology approaches will be compared and evaluated from a case study perspective.
Theme: Mitigation Measures for Reducing P Losses (5), 2014
Main Research Area:
7th International Phosphorus Workshop - IPW7, 2014