Process & contact
Members of ESPP
Sewage sludge digestate, before dewatering, from WWTP using iron salts for chemical P removal
Product: vivianite (iron(II) phosphate).
Can be used as an iron fertiliser. Or possibility to process to PK fertiliser and iron coagulants for use in WWTPs
Precipitation of iron phosphate in the form of vivianite, by reducing iron(III) to iron(II) in anaerobic conditions (digester), then recovery of the vivianite by magnetic separation. Vivianite can be used as an Fe fertilizer to treat Fe-chlorosis of for instance olive treas. Optional extraction of P from vivianite to liquid PK fertiliser and recycle iron as coagulant to WWTP
Manual 1 m3/h pilot for magnetic separation of vivianite tested at Nieuwveer WWTP, NL (2019).
Automatic 1 m3/h pilot (photo) currently in operation, with continuous trials in Germany (2022), Denmark (first half of 2023) and the Netherlands.