A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand.

Thesis (M.Eng.) - Asian Institute of Technology, 1972

A series filtration water treatment system using local materials was developed for treating surface water in small communities of Asia. Design criteria were developed using coconut husk fiber as roughing filter medium and burnt rice husk as polishing filter medium. The optimum filtration rate was 1.25 m3 /m2 /hr for both filters. The optimum depth of media using series filtration units was at 100 cm for coconut husk fiber and 80 cm for burnt rice husk. A dual media filter, comprising coconut husk fiber of 80 cm depth followed by burnt rice husk of 20 cm depth, fed at a filtration rate of 1.25 m3 /m2 /hr, had efficiencies for turbidity and coliform removal greater than 99% when treating surface waters. Duration of the filter run, using the dual media, would approximate one month's operating time based on current village water use habits in Thailand. The dual media filter appears promising as a tertiary waste treatment process also. For raw water sources with turbidity less than 40 JTU, a single media filter of burnt rice husk, fed at filtration rate of 0.25 m3 /ma/hr, proved to be satisfactory to provide a high efficiency of turbidity and coliform removal.