Removal of Released Phosphorus in Anaerobic Digested Activated Sludge Using Thickener Sludge Generated During the Total Phosphorus Removal Process in the Municipal Wastewater Treatment Plant
In this study, the thickener sludge(PS-sludge) generated at total phosphorus(T-P) removal process was introduced into anaerobic digested activated sludge to examine the role of PS-sludge in immobilizing phosphorus and also in improving dewaterability of the mixed sludge. Maximum absorption capacity of phosphorus from the Langmuir isotherm plot was 9.3 mg/g-sludge(dry wt.) for PS-sludge. Experimental results observed T-P removal of 87% using a PS-sludge concentration of 1.66% TS(total solids), and the simultaneous decrease in COD(chemical oxygen demand). However the use of PS-sludge resulted in the deterioration of the dewaterability of mixed sludge by increasing the SRF(specific resistance to filtration). The results indicated that PS-sludge can further be used as absorbent media for T-P removal from the reject water, despite of the deterioration of the sludge dewaterability.