Sanitation infrastructure and their potential impacts on human health: A case study of Tembalang sub-district in Semarang City, Indonesia

Abstract

Purpose / Context - The provision of reticulated sanitation infrastructure has not kept pace with the rapid urbanization, which can be witnessed in Indonesia. In addition, lack of proper sanitation infrastructure treaty led to pollution of groundwater. The most common system used for human ex-creta disposal system in Indonesia is septic tank, which is an on-site treatment system, is waste disposal from inadequately designed or maintained septic tanks can lead to the contamination of the shallow groundwater.. Unfortunately, the shallow groundwater is being used as a potable water re-source by a significant fraction of the urban population due to inadequate coverage of reticulated water supply, which can negatively affect the human health. This research study intended to investigate the impact of on-site sanitation systems on groundwater quality of dug wells, which was carried out in three villages in Tembalang sub-district of Semarang. Methodology / Approach - Water samples from 22 selected shallow wells (at least 7 each village) were analysed for biological (total coliforms and E. coli), chemical (Nitrate, Chloride, COD, pH) and physical (Total Dissolved Solids and Temperature) parameters of water according to Indonesian National Standard (SNI). Open space ratio, septic tank density, drainage density, soil permeability were also determined for incorporation into the envisaged analysis. House owners and septic tank builders were also interviewed using a structured interview. Results - It was found that most of the septic tanks were constructed without lined bottoms as pit latrines and no additional leach field was provided. Generally, the septic tank was located in the back yard, while shallow well was in the front yard. This condition did not only make the sludge removal problem, but also difficulty in maintain safe distance between the septic system and the well. The groundwater quality during dry season was considerably better than that during rainy season. The study also revealed that 55%, 30% and 50% of water samples contained Nitrate, COD and E. coli, respectively, which exceeded the Indonesia Health Ministry Standard for drinking water. Key Findings / Implications –The study results presented that even though the distance between septic tank to shallow well could be more than 10 m, the groundwater was still found to bemicrobiologically polluted. A communal sanitation system such as Small Bore Sewerage could be one of the options to be considered for minimizing the potential groundwater pollution.