PHOXNAN - Phosphorus Recovery by a Hybrid Process of Low Pressure Wet Oxidation and Nanofiltration

Goal of the PHOXNAN-project is to prove the feasibility of phosphorous recovery from sewage sludge by a hybrid process of low pressure wet oxidation and nanofiltration at acidic pH.

The process stages of low pressure wet oxidation (LOPROX), solids separation, nanofiltration and phosphorous conditioning will firstly be investigated in laboratory scale separately. Afterwards the complete process will be optimised in bench-scale. The assessment will include ecotoxilogical and quantitative analytics.

The LOPROX will be optimised with respect to three goals: phosphorous dissolution, amount and composition of residual solids, and elimination of organic micropollutants.

The nanofiltration will separate heavy metals from the phosphorous compounds which, at the acidic pH of the LOPROX process, will pass the membrane and can be recovered in high purity from the permeate.

The results from the project will allow a substantiated assessment of the potential of this new process and be the basis for the further investigation and development in pilot-scale.