Influence of sludge ozonation on MBR performance efficacy

The technical study of sludge reduction of combining the chemical method with biological method was developed, with integrating the merits of MBR and sludge ozonation. The characteristics of sludge ozonation and its influence on MBR performance were investigated. The solubilization of sludge cell improved with the increase of ozone dose, but the properties of mixed sludge liquor (MLVSS, SCOD) changed slowly when the dose was above 0.16mgO₃/mgMLVSS. Under the optimal dose, 53.1% of MLVSS was solubilized by ozone; while SCOD and TN raised 1287 and 143.9 mg/L, respectively. The ratio of C/N in liquor phase was only 8.6 due to the oxidation of organic by ozone. Through parallel running of three MBRs systems (amounts of sludge ozonation were 0, 0.5% and 1% of influence flow rate respectively), ozonation could reduce markedly the sludge production rate of the system (the sludge production rate of 0.5%Q and 1%Q systems were only 0.17 and 0.12kgMLSS/kgCOD, with reduction of 29% and 50% respectively in comparison with the 0Q system); meanwhile, no obvious influence was observed on nitration and organic removal, the outflow water quality of the system was good.