Process & contact
Member of DPP
Raw or digested sludge after dewatering, from WWTPs operating biological and/or chemical P-removal.
P > 8% (P2O5 > 18.3%)
Ca: 2 – 6 %
1) continuous hydrothermal hydrolysis carbonization process at 175°C, 20-25 bars.
2) Acid treatment of hydrolysed sludge to dissolve P.
3) Mechanical separation into low-P solid “coal” and P-rich liquid filtrate.
4) Phosphate precipitation from the liquid to produce a calcium phosphate salt.
Full scale plant operating on dewatered sewage sludge in China (since 2016) input capacity 2 t/h
Demonstration plant at Ruhrverband/Duisburg Germany, input capacity 250 kg/h.