Abstract
The composting toilet with low operation and production cost was developed to evaluate its operation performance and cost. It is a kind of urine diverting toilet with hand mixing device for no power requirement. As a result, weight of composting matrix increased with increasing total weight of loaded feces. The 50% of organic matter was biodegraded. The moisture content increased at initial then became stable at 55%. Organic acids were generated in the matrix at initial, but no acids were detected after 2 weeks. Some inactivation process of pathogens was required, because E-coli and coliform count was higher than conventional composting toilet with heating device. The required force for mixing increased with operation progress, but it could get small by adoption of reducer. However, adoption of reducer causes decrease of rotation number of screw and increase of force loading to the screw, relatively. The loading force from the matrix was increased with increase of weight of mixed matrix and decrease of distance between screw blade and reactor wall. The material cost in Japan was 220000 yen and over half was occupied by production of screw. In Indonesia, it was Rp. 10, 000, 000, (=100, 000 yen) which value is over usual construction cost for toilet. The material cost of PVC for reactor wall occupied 66%.
