There is a growing need to utilize sludge generated by sewage treatment plants in agricultural communities; that is, converting sludge into compost to reclaim open spaces and farmland. The sludge generated from effluents of 500 to 3,000 inhabitants merely amounts to 10-70kg/day (dry weight), and maintenance work is usually scheduled once or twice a week for these sewage treatment plants. While materials such as rice husks, wood chips, and sawdust are commonly used for absorbing the moisture of sludge, some of these materials are scarcely available in some regions. Meanwhile, compost facilities should be compact and inexpensive if they are to be installed in each sewage treatment plant. In consideration of these requirements, and based on the conditions listed below, a series of verification tests was conducted on compact compost facilities:
(1) The facilities should be based on an intermixing-type fermentation system.
(2) The facilities should not use any materials for absorbing moisture (rice husks, etc.).
(3) The facilities should adopt a batch treatment system to accommodate patrol maintenance work (once or twice a week).
(4) The fermentation process should continue for more than 48 hours at 65℃ or above.
(5) The phytotoxicity and fertilizing effects of finished products on plants should be verified.