Environmental implications of sewage water overflow : a case study of Cosmo City, Johannesburg, South Africa

Abstract

Cosmo City, situated in Johannesburg, Gauteng, has been experiencing SWO in previous years which poses a significant threat to the environment and water bodies such as wetlands, rivers, and streams. This raises concerns about the water quality of Zandspruit river as well as human health risks potentially posed by the level of pollution to the surrounding water bodies. The study aimed to investigate the impacts of sewage water overflows into the Zandspruit river, and the perceptions of the community towards SWO. Water samples were collected from Prestine Spruit stream a tributary of Zandspruit river for 12 months from 3 sampling sites of the stream for analysis. Water quality parameters such as pH, temperature, electrical conductivity, and total dissolved solids were measured in the field using a water quality multimeter, while other parameters such as turbidity, metals, nitrates, phosphate, COD, and E. coli were analysed at SANAS accredited laboratories. The results were compared to the South African water quality guidelines and other set standards. Most of the water quality parameters were found to be within the permissible standard limits with COD, E. coli and turbidity being the only parameters found to be above the permissible set standards. The detection of COD, E. coli and turbidity above set standards, is an indication that the river water is highly polluted. Perceptions of the community towards SWO was studied using a survey, through the distribution of questionnaires to community members. The purpose of the questionnaire was to assess community’s perceptions towards SWO. The survey was carried for a period of 3 months. On the survey results, the community perceived that the main causes of sewage water overflows were population growth, blockage, and broken sewers. The community also perceived that sewage water overflows are negatively impacting the environment, human health, river water quality, and the economy. The survey results are in conformity with experimental results. The overall results of this study revealed that sewage water overflows surrounding Cosmo City are negatively impacting the river water quality and poses health risk concerns. Therefore, there is a need to monitor and manage sewage water overflows in Cosmo City to mitigate any negative impacts that arise because of sewage water overflows.