Laboratory-scale studies were undertaken to investigate the influence of varying hydrolysis conditions on the composition and amount of the produced hydrolysate, as well as the quality of hydrolysate as carbon source for denitrification. Three parameters were targeted for optimization, namely, temperature, retention time and pH value. The results showed that a soluble COD in the order of 18% in terms of sludge total COD at a temperature of 35°C, initial pH value of 6.4 and a retention time of

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... 0 hours was achieved. At an initial pH value of 11, a temperature of 20°C and a retention time of 6.0 hours an increase up to 28% soluble COD was obtained. A significant soluble COD production of about 45% could be obtained at a temperature of 35°C, pH value of 11 and a retention time of 6.0 hours. The use of the produced hydrolysate had succeeded to improve the denitrification rate up to 9.75 mg NO 3 -N/g VSS *h. Simultaneous removal of phosphorus up to 1.0 mg P/l was obtained.