Enhanced effect of sludge reusing and PAC adsorption process on organic matter removal

The enhanced removal of turbidity,DOC and UV254 by integration of sludge reusing and PAC adsorption process is investigated in jar tests,and the effect of integrated process,conventional coagulation and sludge reusing alone on turbidity and organic matter removal is also compared.The results indicate that removal of turbidity,DOC and UV254 by the integrated process could reach up to 89.2%,52.7% and 60.1%,respectively,which is higher than conventional coagulation by 12.4%,33.3% and 24.7%,respectively.The DOC and UV254 removal of the integrated process is higher than sludge reusing alone with PAC by 9.5% and 5.9%.The enhanced removal effect on turbidity and organic matter by integrated process may be due to the combination of adsorption and sweeping by hydroxide precipitates and the adsorption of PAC existing in mixed sludge with PAC.The residual aluminum content of the effluent of integrated process is slightly more than raw water but less than that of conventional coagulation.The effect of integrated process on turbidity,DOC and UV254 removal is significantly influenced by the turbidity of raw water,it's better to apply the integrated process within the turbidity of raw water less than 100 ntu.