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 (C(OW)/N(OW) ratio), and the water-soluble organic carbon to total organic nitrogen (C(OW)/N(OT)) 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. (C) 2010 Published by Elsevier Ltd.