The main raw water source for the Kinmen Water Treatment Plant (WTP) is reservoir. Due to the long term contamination by municipal wastewater, the reservoir is severely eutrophicated especially in summer. The deteriorated raw water quality has caused poor operations in pre-oxidation and coagulation/flocculation. As a result, the organic contaminants cannot be effectively removed in the subsequent sedimentation or floatation processes, which burdens the rapid filtration operation and causes filter clogging. The slow filtration unit followed has been proved ineffective in lowering the concentrations of contaminants, such as organic matter, iron and manganese. After post-chlorination, the residual trihalomethane, iron, and manganese exceed the drinking water standard, which jeopardizes the drinking water safety of residents. For this reason, we propose to upgrade the treatment units of Kinmen WTP with high-efficiency chemicals and filter media to improve the operational performance and the drinking water quality of residents. This project will first evaluate the raw water quality of the Kinmen WTP, and identify the main causes for poor treatment efficiency. After that, optimum dosing model for the combination use of oxidants (NaOCl, ClO2 or KMnO4) and coagulants (Alum or Polysilicate iron) in removing organic contaminants will be evaluated. Then, the efficiency of organic matter removal by rapid filtration with a high-performance filter media (granular activated carbon coupled with manganese sand) will be evaluated. A water quality improvement strategy including cost analysis will be provided. Finally, a standard operation process (SOP) for water quality improvement will be established for individual WTP, which will be compiled into a training book. In addition, training sessions will be conducted to strengthen the water treatment competency of water treatment operators to provide residents with quality drinking water.