Sewage sludge disintegration by combined treatment of alkaline + high pressure homogenization

Alkaline pretreatment combined with high pressure homogenization (HPH) was applied to promote sewage sludge disintegration. For sewage sludge with a total solid content of 1.82%, sludge disintegration degree (DDCOD) with combined treatment was higher than the sum of DDCOD with single alkaline and single HPH treatment. NaOH dosage ⩽0.04 mol/L, homogenization pressure ⩽60 MPa and a single homogenization cycle were the suitable conditions for combined sludge treatment. The combined sludge treatment showed a maximum DDCOD of 59.26%. By regression analysis, the combined sludge disintegration model was established as 1 1 - DD COD = 0.713 C 0.334 P 0.234 N 0.119 , showing that the effect of operating parameters on sludge disintegration followed the order: NaOH dosage > homogenization pressure > number of homogenization cycle. The energy efficiency with combined sludge treatment significantly increased compared with that with single HPH treatment, and the high energy efficiency was achieved at low homogenization pressure with a single homogenization cycle.