Minimization of activated sludge production by chemical uncoupler, 3,3,4,5-tetrachlorosalicylanilide

• Main Author: Seah, Siew Ying.
• Other Authors: Liu Yu
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Environmental engineering::Water treatment
• Online Access: http://hdl.handle.net/10356/15918
• Institution: Nanyang Technological University

Activated sludge process is one of the most common biological processes in wastewater treatment plants worldwide. Due to its contribution to higher operating cost, excessive sludge produced in the activated sludge treatment process is a vital problem that needs to be solved. This report aims to describe the effect of fixed metabolic uncoupler concentration of varying initial biomass concentrations on reduced sludge growth in activated sludge batch culture. 3,3,4,5- tetrachlorosalicylanilide (TCS) was chosen as the uncoupler to carry out the batch tests. Sludge growth, organic removal efficiency, pH, microbial morphology and particle size were analyzed in relation to the batch experiments. Activated sludge obtained from Ulu Pandan Water Reclamation Plant was cultivated and used throughout the project period. Throughout the project, a series of batch experiments (4 hours in duration) were carried out with varying initial biomass concentrations from 250 to 1000 mg/L at a fixed TCS concentration of 1 mg/L. Batch experiments without additions of TCS were carried out to act as a control. It was found that sludge reduction was related to the amount of relative TCS concentration to initial biomass concentration. A shift in predominant microbial population to filamentous bacteria and a dropped in pH were also observed after the introduction of TCS. TCS can successfully reduce sludge growth in the activated sludge batch culture but at the same time, it will affect organic removal efficiency. It has been discovered that the amount TCS surrounding per unit of biomass can better reflect the real strength of TCS exerting on biomass, rather than the initial TCS concentration alone.