A thesis submitted in partial fulfillment of the requirement for the degree of Master of science

Thesis (M.Sc.) - Asian Institute of Technology,1992

I n this study water hyacinth a nd solid waste were mixed at the different rati os and were converted to soil conditioner or fertilizer by composting process. Bacterial seeding was added to accelerate the maturation t ime. Th e experime nts were conducted i n Vietnam and in Thailand. The mode of composting process in Vietnam was Chinese ground- surface aerobic composting and ratio of water h yacinth to solid waste was 4: 1 with bacterial seeding 0 . 01596 of dry weigh t. Experiment in Thailand was undertaken by forced aeration mode of composting. It comprised of two runs. In run 1 ratios of water hyacinth to solid waste in three piles were as followed: pil e 1 = 4:1, pile 2 = 3:2, pile 3 = 2:3 and bacterial seeding of three pil es was 0.015%. After obtaining t h e optimal ratio of water hyacinth to solid waste run 2 was carried out with that ratio and diff erent size of bacte rial seeding. Pile 4 = 0.010%, pile 5 = 0.015%, pile 6 = 0 . 025%. The resul ts s howed that time required for composting process to reach maturation time was much l onger i n Ch i nese ground- surface aerobic composting pile than in forced aeration p iles. Optimal water h yacin t h to solid waste was 4:1 and bacterial seed i ng sizes from 0.010% to 0.025% gave a lmost the same acceleration rate of mat ura t ion t ime. Final compost product can be served as soil conditione r. Further investigation about op timal water hyacinth to solid waste ratio oth e r than those in t h is study would be recomme nded. The time required for composting process in Chinese ground- s u rface aerobic composting pile in different seasons in Vietnam should be studied.