General ESR project research structure:

P-TRAP consists of 11 ESR projects (see below), which are organised in three scientific work packages (WP1 – WP3) to maximise methodological and thematic interlocking. Each ESR contributes to at least two WPs. Research is driven by applied research questions from the private and non-academic sector and guided by a network of scientists covering a broad area of complementary scientific expertise.

The complimentary non-academic partners cover the different related business areas to facilitate the dissemination and implementation of results achieved within P-TRAP;  e.g. application of new technologies to sequester P from water, or production of fertilisers. Regarding this last point, the use of recycled sources of P has been identified as a crucial aspect by all the stakeholders in the use of P. Non-academic partners are key players in P-TRAP. Their involvement ensures an application-oriented perspective on P-TRAP research and maximises acquaintance of ESRs with the non-academic sector. Each ESR will perform secondment projects driven by applied research needs of the non-academic host.

The applied methodology used in the ESR projects is diverse but can be categorised as follows:

• Design and implement field experiments on the retention of P in drainage systems (WP1) and P binding in lakes by Fe amendment (WP2).
• Rigorous investigation of field sites which have been subjected to Fe amendments in the past to study long-term effects which extent of the time scale of years and decades: agricultural sites in which Fe-containing sorbents have been installed in drains (WP1), agricultural areas in which vivianite fertilization had been performed (WP1), and lakes which have experienced addition of Fe(III) salts (WP2).
• Performing laboratory experiments to investigate key processes under controlled conditions. These processes include sorption of P to Fe-containing solids, transformation of Fe minerals induced by aging or by changes in redox conditions, and release of Fe and P from P-containing Fe minerals under rhizosphere conditions (WP3).
• Development of mechanistic and quantitative models for developing a conceptual framework for P-TRAP technologies, designing laboratory and field experiments, and to evaluate the applicability of P-TRAP technologies depending on field conditions (all WPs).

The following ESR projects belong to P-TRAP:

ESR 1: Development of an on-site phosphorus retention technology

ESR 2: Effect of applying vivianite and P-containing Fe(III)oxides on P bioavailability and dynamics in different agricultural soil types

ESR 3: Improving the management of surface waters draining agricultural areas to optimise the retention and recovery of Fe-associated P

ESR 4: Converting Fe residual materials into filter-stable sorbent materials for P removal 

ESR 5: Microbial technologies for converting P-loaded Fe(III)oxides

ESR 6: Process controlling P dynamics upon reductive transformation of P containing Fe minerals

ESR 7: Mechanistic studies on the transformation of P-containing Fe oxides

ESR 8: The effectiveness of vivianite as a sustainable Fe and P fertiliser for agricultural crops

ESR 9: Studying the effect of Fe addition to sediments on the sedimentary biogeochemical processes

ESR 10: Biogeochemical mechanisms influencing the bioavailability of P and Fe from vivianite

ESR 11: Effects of Fe supplementation on the ecology and P dynamics in eutrophic lakes