Tiev Visoth creator Chongrak Polprasert Chairperson Ha, Sung Ryong Co-Chairperson Preeda Pakpian Examination Committee Trankler, Josef Examination Committee Swedish International Development Agency (SIDA) Scholarship donor text series technical report th Bangkok Asian Institute of Technology 1999 continuing eng 112 leaves The Tonle Sap River Basin plays a key role in supplying as raw water to Phnom Penh City, Cambodia. The purposes of this study were: to evaluate water quality characteristics in the Tonle Sap water basin, identify problems of water supply quality and conduct experiments on water hyacinth pond (WHP) systems to improve quality of raw water from the Tonle Sap river. Various aspects of water quality were studied at four locations of the main path of the Tonie Sap River. Raw water, treated water and distributed water from households from four districts were analyzed. Experiments on WHPs were conducted to investigate the treatment efficiencies by changing HRT and varying the percentage of plant harvesting. The results showed that quality of the Tonie Sap water, treated water and distributed water fluctuated with time and exceeded recommended WHO and MRC raw water and drinking water quality standards. For example, the TSS concentrations of raw water from Tonle Sap river were 80-600 mg/L, exceeding TSS the MRC raw water quality standard of 25 mg/L. The WHP experiments found the optimum conditions of WHP to be: HRT of 3 days, plant harvesting at 50% of the pond surface area; the k value was 30.7 m/yr. The use of WHPs to pre-treat the raw water supply could improve the raw water quality to meet the raw water quality standards. A thesis proposal submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development Thesis (M.Sc.) - Asian Institute of Technology, 1999 Water quality Cambodia Phnom Penh Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B12096 http://203.159.5.9/ait-thesis/detail.php?q=B12096 041199 20260818112723.0