The impacts of on-site septic tank wastewater disposal in Kampala city

The use of septic tanks as an appropriate decentralized wastewater treatment solution to an inner city area of Kampala has been investigated. Several large septic tanks servicing hostels were monitored in addition to the water quality of four springs used as water source for the local population: two springs sited downstream of the septic tank percolation areas compared to two adjacent springs located within the surrounding unplanned settlements with several pit latrines. Although the septic tanks did not discharge into a constructed percolation area and had not been properly maintained, it has been shown that the unsaturated sandy subsoil acted to attenuate significantly the pollutants and protect the downstream springs. In contrast the springs situated within the unplanned development showed higher levels of contamination which was attributed to poor spring construction in combination with adjacent sources of faecal pollution from pit latrines and surface runoff.