Ballasting Agent for Immediate Solving of Sludge Bulking in Activated Sludge Process

Abstract

This research studied the effects of ballasting agent for immediate solving of sludge bulking problem in activated sludge process. Three types of ballasting agent with 4 average sizes, talc (8, 19, 41, 65 µm) powder activated carbon (PAC) (133, 213, 365, 802 µm) and crumb rubber (223, 408, 450, 644 µm) were tested.  Concentrations of ballasting agent were also varied, i.e. 0%, 20%, 50% and 100% of sludge concentration were also tested. The initial settling velocity (ISV) and sludge volume index (SVI) were used to demonstrate the sludge settling efficiency.  The results showed that all three ballasting agents could immediately increase an initial settling velocity and showed a low SVI. Small size and high concentration of all of ballasting agent could improve settling efficiency, which indicated from higher the ISV, 393%, 77% and 23% for talc, PAC and crumb rubber respectively than the control without ballasting agent in every condition. So results showed that all of ballasting agent could solve the immediate problem of sludge bulking while the talc addition made the highest ISV.