The project intends to design, fabricate and test a highrate anaerobic reactor that can treat the domestic wastewater and produce biogas as a byproduct. The biogas is a combustible mixture of methane, carbon monoxide, hydrogen gases etc. and can be used in the table burner. The target of the biogas reactor is to treat the wastewater generate from domestic wastewater at Kathmandu University. The major outcome of this project is to be a working design of the biogas digester which can be fabricated and can be coupled with domestic septic for the domestic wastewater treatment. The septic tank uses as a primary treatment of the wastewater whereas UASB is taken as a secondary treatment. We design pilot scale UASB wastewater treatment system and test know the proper operation of the reactor. The septic tank-UASB combine system has TSS and CODt removal efficiency of 83% and 88% respectively. This system is one of the appropriate systems for onsite wastewater treatment in the developing country. (C) 2019 Elsevier Ltd. All rights reserved.