Following conclusions are drawn from this study. The start-up of UASBCD reactor required a period of 120 days. In case of UASBASDIT reactor sludge bed was stabilized in a period of 80 days. The performance of both reactors to treat wastewater was enhanced with an increase in the temperature and sludge age. Overall performance of both reactors was optimal at sludge age ranging from 120 to 150 days and temperature varying between 25 and 30 C. The UASB technology provides a low-cost system for the direct treatment of municipal wastewater and can be applied in small communities where the wastewater flow variation is high due to rainy season or population load increases during the tourist season or due to seasonally operated food industries.