Abstract
It is necessary to make high quality compost in order to expand the utilization of biosolid produced in sewage treatment plants. The high quality compost should not only possesses characteristics of ordinary compost, but also has superior ability to improve soil properties and contains more plant nutrients. Additives, which were possessed of two functions, were used in this research. One is called bulking material function that contributes to adjusting moisture content and improving the permeability of air during the active composting. The other is called soil amendment function that contributes to improving soil properties and to balancing plant nutrients. Cedar chips, zeolite, charcoal and rice bran were used in this study. The results indicate that cedar chips are the suitable bulking material because it possesses large water adsorption capacity and low bulk density. Zeolite not only has high ability of NH3 adsorption but also possesses large value of cation exchange capacity (CEC). Charcoal functions as soil amendment. Rice bran contains a fairly high amount of plant nutrients. The compost in which cedar chips, zeolite, charcoal and rice bran are added contains high ability of improving soil property and fairly amounts of plant nutrients. Using these materials as the additives, the high quality compost was produced.
