Effect of microwave irradiation on the disintegration and acidogenesis of municipal secondary sludge

This work experimentally determined the effect of microwave treatment on the disintegration and acidogenesis of municipal secondary sludge. Sludge samples (500 g) were heated for 0, 3, 5, 7, 9, 11, and 15 min in a microwave oven (2450 MHz, 700 W). The solubilization degree (soluble chemical oxygen demand (SCOD)/COD) of sludge increased asymptotically with microwave irradiation time from 2% at 0 min to 22% at 15 min. The concentrations of soluble protein, carbohydrate, lipid, and calcium also increased with microwave irradiation time. The biochemical acidogenic potentials (BAP) of sludge increased from 3.58 to 4.77 g COD l−1. The results show that microwave irradiation increases the solubilization degree and BAP of municipal secondary sludge.