Sustainable communal septic tank systems in informal settlements : the case of Lebak Siliwangi, Indonesia

This study focused on realizing Sustainable Development Goal (SDG) 6 for inclusive clean water and sanitation; in particular Target 6.3, which aims to reduce untreated wastewater by 2030 while promoting circular wastewater reuse and recycling globally. The main objective was to assess the adequacy and efficiency of communal septic tank systems in informal settlements while helping local planners and authorities in their decision-making regarding Target 6.3. Quantitative and qualitative approaches were employed with secondary data from previous researchers, and primary data were collected from field surveys, observations, and interviews with members of the local community. The research was delimited to two village administrative divisions known as Rukun Warga (Village Administrative Division, RW): RW 7 and RW 8 of Lebak Siliwangi Kampung in Coblong District, Bandung, West Java, Indonesia. The findings were also compared with situations in other informal settlements in Brazil, Bangladesh, and Nairobi. The results indicated the inadequacy of communal septic tanks in informal settlements due to factors such as substandard system design, limited support and communication between authorities and residents, and the gap between septic tank availability and capacity vis-a-vis demand. Other limiting factors included limited land availability and irregular geomorphology, the latter of which affected the siting and operation of septic tanks due a lack of room for upgrades or expansion in response to continuous population growth. These findings illustrate the need to complement communal septic systems with flexible centralized or decentralized systems to achieve Target 6.3 of SDG 6.