Sustainability of a simplified sewer system (Tanzania)

This study was conducted to assess the sustainability of the simplified sewer system (SSS) for its potentiality of up-scaling and replicating elsewhere with similar challenges by assessing the sanitation status before introduction of simplified sewer system and sanitation status after introduction of simplified sewer system. The methodology involved collection of data on performance of different components of the sanitation service chain in the study area; and determination of sustainability index using a set of indicators. Data collection techniques include literature reviews, household questionnaires, expert surveys, and physical observations. Data analysis utilized the analytical hierarchy process (AHP) to assign weights to sustainability indicators, the urban sanitation status index (USSI) was used to evaluate the status of the sanitation service chain, and the sanitation sustainability index (SSI) determined the level of sustainability of the sewerage system. Results showed that the emptying and transport component of the sanitation service chain performed better, with a USSI value of 0.905. However, the system performed poorly on the complementary services (stormwater, greywater, and solid waste management), which had a USSI value of 0.552, probably due to fewer investments in these services. On the other hand, the sustainability of the simplified sewer system was found to be high, with an SSI score of 76.5%. Hence, it can be concluded that, the simplified sewer system is an appropriate option for addressing safely managed sanitation in unplanned urban settlements with poor households where connection to conventional sewer systems is challenging.