The Effects of Alkaline Treatment on Excess Sludge Supernatant Characteristics

The effect of alkali treatment on excess sludge supernatant characteristics was studied in this experiment. 4 mol/L sodium hydroxide solution was utilized to adjust the initial pH value of excess sludge to 9.0, 11.0 and 13.0. Batch experiments were operated in 35 °C shaking bath for 12 h. The soluble chemical oxygen demand (SCOD), protein and polysaccharide concentration in excess sludge supernatant was measured every 3 h. The experimental results showed that maximum amount of protein, polysaccharide and SCOD were obtained when the initial pH value was 13.0.