The effects of rice husk, sawdust and rice bran on the composting process of food waste were studied in a
180-L laboratory composter based on a mixture experimental design. Linear and quadratic models of
seven important process characteristics (composting and acidification times, lowest and final pH values,
highest temperature, the water-soluble organic carbon to water-soluble organic nitrogen (COW/NOW
ratio), and the water-soluble organic carbon to total organic nitrogen (COW/NOT) ratio) in terms of fractional
compositions of bulking agents as well as the water absorption capacity and the free air space
of the composting matrix were developed.