Water and nutrient recovery from stored urine by forward osmosis with an ammonium bicarbonate draw solution

Forward osmosis with an ammonium bicarbonate draw solution was investigated as a low energy non-sewered sanitation solution, to recover nutrients and water from source separated urine. Stored urine collected Urine Diversion Dry Toilets in the eThekwini Municipality (Durban), South Africa used feed solution. Water recoveries of up 45.9% fluxes 6.0 L m −2 h −1 were achieved using undiluted stored over 8-h operating period 2.5 M Rejections 95% for phosphates, 85% nitrogen chlorides, 75% potassium sodium achieved. Low fouling membrane observed after multiple runs cleaning by circulation deionized or osmotic backwash sufficient >95% original flux. Little irreversible detected, assumed be caused carbonate calcium scaling SEM-EDX analysis. This study suggests that forward could integrated closed loop nutrient recycling technology prospect clean recovery use waste heat from, example, fecal sludge combustion.