Process & contact
Kemira iron / aluminium phosphate
Member of ESPP
Contact 
Updated 11/2021
Input materials
Upgrading of existing sewage treatment works
Output products
Iron or aluminium phosphate
Process description
1) Optimisation of primary and secondary (biological) treatment by polymer dosing with control algorithms giving increased biogas production
2) Tertiary P-removal with iron and/or aluminium coagulants, control algorithms, separation by settling and/or centrifugation to produce a P-rich sludge, <10% C-org, containing >50% of WWTP incoming P. Can be installed at smaller WWTPs and recovered material treated at centralized treatment process.
3) Optionally further processing of the P-rich sludge, by drying, granulation, or separation of P and Fe or Al to produce phosphoric acid, phosphate salt and Fe or Al coagulant for water treatment
Operating status
Tested at full scale at two WWTPs (63,000 pe and 130,000 pe) for 1-7 months, and at pilot scale at three WWTPs for 2-3 months.
Iron phosphate granules have been tested as fertiliser in pot trials with rye grass.
Photos: NPK fertilizer granules including iron phosphate (left). Recovered aluminium phosphate pellets (right). Pilot set up for P-rich sludge separation in tertiary unit (bottom).