WP 3: Mechanistic studies on P dynamics during Fe phase transformation

Within WP 3 we aim on the development of deterministic, quantitative models for processes and mechanisms controlling the behaviour of P during the transformation of Fe minerals.

WP 3 is lead by the Swiss Federal Institute of Aquatic Science and Technology (EAWAG), and has the following objectives:

i) Unravel mechanisms controlling transformations of P-containing Fe(III) oxides in soils, sediments, bioreactors and drainage Systems
ii) determine kinetics of the Fe phase transformations and the corresponding release or uptake of P
iii) creating quantitative models for predicting and interpreting the behaviour of P containing Fe phases in natural and engineered environments

To achieve the objectives, WP 3 has several tasks. Each task involves several participants and leads to distinct deliverables and milestones, which have to be reported towards the EC.

Task 1: Systematically investigate transformations of P-containing Fe(III) oxides in laboratory experiments (EAWAG, UU)
Mechanisms and kinetics of the transformation of P-containing Fe minerals upon aging or change in redox conditions will be studied and the controlling factors will be determined.

Task 2: Develop kinetic models for transformations of P containing Fe phases (all beneficiaries)
Empirical rate laws for the transformation of Fe phases obtained from laboratory experiments will be integrated and tested in models for the Fe and P dynamics in the soils, sediments, drainage systems and bioreactors.

Task 3: Investigate the temporal dynamics of solid-bound Fe and P in the studied systems (all beneficiaries)
The speciation of Fe and P will be determined in all investigated systems (soils, sediments, drainage, bioreactors) and their changes due to phase transformations will be elucidated.

Task 4: Characterising solid-bound Fe and P with state-ofthe-art microscopic and spectroscopic techniques (EAWAG, UU, UNIVIE, UNIMAN)
Spectroscopic and microscopic techniques, including synchrotron-based X-ray spectroscopy will be applied to investigate the association of Fe and P down to atomistic level.


D3.1 (due month 36, lead EAWAG, public): Kinetic models for the transformation of P containing Fe phases – Report or scientific publication on the development of kinetic models for the transformation of P containing Fe phases

D3.2 (due month 40, lead UNIVIE, public): Report on the fate of P during Fe phase transformations – Report or scientific publication on the fate of P during Fe phase transformations in soils


MS5 (due month 9, lead KU Leuven): Protocol solid characterisation – A procedure for standard characterisation of Fe and P phases in soils and sediments to be shared by all partners has been established (report)

MS16 (due month 40, lead UU): Management assessment – Validated management assessment completed (report)