Decentralized Wastewater Treatment System (DEWATS) and Desludging Service for Hin Heup Town

Hin Heup, a district capital with moderate economic profile, is located only 2 hours from the capital of Vientiane. The site was chosen by the Groupe de Recherche et d'Echanges Technologiques' (GRET), a French nongovernment organization (NGO). Hin Heup was selected for the project because of its topography, which is appropriate for the construction of a gravity sewer system, and with its villagers' willingness to pay for simple sanitation services.

While 99% of the town’s households already utilize pourflush latrines, simple soak pits were preferred rather than sealed septic tanks. Out of these households, only 24% have engaged desludging services for their pits when full, with the rest either opting to build a new one or have yet to fill their pit. Additionally, only 10% of households have any form of grey water collection. Hence, the town has a relatively high risk of surface (Nam Lik River) and groundwater contamination, which would likely threaten the environment as well as the sources of drinking water for the town’s population. Given this scenario, the decentralized wastewater treatment system (DEWATS) and desludging service project was developed for Hin Heup Town.


Martin Lemenager, GRET Laos
Email:, Chanhsouk Simai, GRET Laos, Frédéric Naulet, GRET Paris