Phosphate is the limiting nutrient in freshwater aquatic systems. Meaning that, if all phosphorus is used, plant growth will cease, no matter how much nitrogen is available. Excessive concentrations of phosphorus can quickly cause extensive growth of aquatic plants and algal blooms. Preventing this phosphate from reaching surface waters, or removing it from there, is therefore a much-needed measure to control eutrophication in areas with intensive fertilization or manure application. On the other hand, phosphate is an increasingly scarce resource and irreplaceable. Moreover the EU has very little domestic P resources and depends almost totally on a handful of countries that control these resources. Measures are under way to recover wasted phosphate from systems such as sewage and slaughter waste, which constitute an important part of the total phosphate flow in Europe, but a roughly equal part is still lost diffusely in agriculture through non-optimized use. Recuperating phosphate from diffuse dispersal therefore has a double advantage: a valuable resource is recuperated, and the vitality of ecosystems is preserved.

Over the last years research has been done in both Belgium, the Netherlands and Sweden on innovative technologies to reduce phosphorus and nitrogen loads from agricultural fields.

The effectiveness of phosphorus and nitrogen removal of many of these technologies has been demonstrated. However, practical field demonstrations are needed to optimize practical applicability, control potential side-effects and improve cost-effectiveness and acceptance. Therefore this proposed project will investigate the efficiency of promising materials to perform this task in real-life situations, thus creating a wholly new technology to capture diffuse phosphates in sorbing filters at drain outlets. This will also allow the potential re-use of phosphates which is a stated goal for national authorities in Europe as well as the EU itself. The integration of existing nitrogen removal technologies in the drainage filter system will also be investigated. In this way both nitrogen and phosphorus limits for surface water can be controlled with one system to fulfill the standards required by the Water Framework Directive.

 A quantified phosphate and nitrogen capture efficiency for materials in field situations:

· Residual P and N levels in solution in a variety of circumstances

· a design for suitable placement of such systems

· a performance-over-time curve

· a strategy for P recovery from saturated systems to ensure it is re-inserted into the circular economy e.g. as fertilizer

· a strategy for removal performance vs. recovery potential

· insights into rollout potential (which areas should be targeted and which levels of P/N are realistic as inputs)

· insights into economic viability, scale of implementation, potential for employment/job creation

 1. Belgium (Flanders)

 · Agriculutal research (2): PCG/INAGRO

 · AVECOM

 2. The Netherlands

 · Research (3) : TNO ; Deltares ; Alterra – WUR

 · Willem Schipper Consultancy (associated partner)

3. Switserland

· Bioptech