This paper describes the monitoring works of Integrated Fixed Activated System (IFAS) which are customized to suit its application in river water treatment plant (RWTP) under River of Life (ROL) project that have been monitored by Departments of Irrigation and Drainage (DID) at Klang river and its tributaries.There are seven RWTP selected for monitoring and testing since these RWTP are monitored by the Malaysian Department of Irrigation and Drainage for River of Life Project. Several types of biological carrier in six (6) different RWTPs will be tested for this study. Sampling schedule differ from each RWTP depend on its design and numbers of available chamber and its operation as well as weather condition. Water quality samples from Inlet and Outlet, MLVSS and TVS in the oxidation tank of the RWTP were collected as grab samples for once per month. This IFAS-RWTP can reduce turbidity to acceptable levels, and the effluent water can be achieved to NWQS Class II standard as initial target by the JPS. Further monitoring and analysis are needed to observe the long-term performance in low strength RWTP process in terms of biofilm formation and water quality for better understanding of the IFAS and MBBR processes