Treatment of sludge water with reverse osmosis

Considering the increasingly stringent requirements on the quality of treated wastewater introduced into surface or ground water, it is reasonable to reduce the loads of biogenic compounds produced already at wastewater treatment plants in sludge treatment processes because sludge water produced in such treatment brings into the process cycle up to 20% more of nitrogen and phosphorus load. The paper presents the results of sludge water treatment in a reverse osmosis process. The concentration of biogenic compounds in sludge water was successfully reduced by 95%. The tests were made using a pilot installation and laboratory installation. The concentrate produced in the reverse osmosis was treated by precipitating nitrogen and phosphorus compounds in form of struvite (NH₄)Mg(PO₄)×6H₂O that can be next used as a fertiliser.