A Thesis 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, 1988

Pilot scale composting of water hyacinth with forced aeration was undertaken with two sets of experiments: three piles for each set. Each compost pile was made from chopped water hyacinth and cesspool slurry. They were experimented upon by the difference of aeration rates and inoculum seeding sizes. The aeration rates were varied at 0.30, 0.54 and 1.54 m 3/day/kg of volatile solids (VS). The inoculum seeding size of 0.015% was used with and without aeration and 0.03% with aeration. The chemical and physical parameters were observed throughout the composting period. Fecal coliform was used as the hygiene indicator. In piles with variation of forced aeration rates, the minimum rate 3 of 0.3m /day/kg of VS gave the greatest reduction in the organic carbon and the C/N ratio. The peak temperature of 59.8°C was observed in the same pile. In the other piles with the variation of size of inoculum seeding, better results in reduction of organic carbon and C/N ratio were observed in the non-aerated pile. A maximum temperature of 56. 1°C was obtained in the same pile. Temperatures beyond 50°C were attained at the pile center for 4 days in aerated piles with seeding and 8 days in the non-aerated pile . In both the experiments, more than 85% of the fecal coliform were destroyed. For a C/N ratio of 28, the optimum aeration for highest decomposition rate required is 0.3m3/d/kg of VS . An inoculum seeding of 0. 015% in a pile of C/N ratio 23: 1 without aeration was found to give better results than those with aeration.