REMOVAL OF PO4 AND NH4 FROM WASTEWATERS BY UASB METHANOGENIC FERMENTATION

The removal of PO4 and NH4 from wastewaters was investigated by stimul ating the formation of precipitates containing PO4 and NH4 in granulat ed sludge in UASB methanogenic fermentation, In a synthetic wastewater containing volatile fatty acids, the removal efficiencies of PO4 and NH4 were 85 (influent = 406 mg/l) and 60% (influent = 100 mg/l), respe ctively, when 8 mM Ca and 8 mM Mg were added in the influent. In a hea t-treated liquor of sewage sludge, a PO4 removal efficiency of 70% (in fluent = 53 mg/l) was achieved by the addition of 2 mM Ca and 3.5 mM M g; removal of NH4, however, was not observed during the experimental p eriods.