A situational analysis of the microbial water quality in a peri-urban catchment in South Africa

• Published in: Water science and technology Vol. 35; no. 11-12; pp. 119 - 124
• Main Authors: VENTER, S. N, STEYNBERG, M. C, DE WET, C. M. E, HOHLS, D, DU PLESSIS, G, KFIR, R
• Format: Conference Proceeding Journal Article
• Language: English
• Published: New York NY Pergamon Press 1997; Oxford IWA Publishing
• Subjects: Applied sciences; Bacteria; Bacteriology; Biological and medical sciences; Catchment area; Catchment areas; Coliforms; Continental surface waters; Dilution; Discharge; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Epidemiology; Exact sciences and technology; Faecal coliforms; Fecal coliforms; Freshwater; Fundamental and applied biological sciences. Psychology; Industrial areas; Industrial pollution; Land use; Microbiology; Microorganisms; Modelling; Natural water pollution; Pathogens; Pollution; Pollution effects; Pollution sources; Pollution, environment geology; Population density; Quality assessment; Rivers; Runoff; Sewage; Sewage treatment plants; Urban catchments; Wastewater; Wastewater discharges; Wastewater treatment; Wastewater treatment plants; Water pollution; Water quality; Water quality assessments; Water treatment and pollution; South Africa; Africa; Virus; Drainage basins; Escherichia coli; Surface water; Water quality; Bacteria; Coliphage; Water pollution; Urban area; Coliforms; Phage; Enterobacteriaceae
• ISBN: 9780080433004; 0080433006
• ISSN: 0273-1223; 1996-9732
• DOI: 10.1016/S0273-1223(97)00245-X

The Rietspruit catchment in the Gauteng province on the outskirts of Johannesburg was selected for study as an example of a small (1120 km2) densely populated (1000 persons per km2) catchment area, representative of many peri-urban situations where populations with few sanitary provisions have grown up on the edge of cities in South Africa. The spatial distribution of land use and water quality in the catchment was assessed. The principal sources of population were identified and the effects of dilution and bacterial die-off on water quality considered with reference to the concentrations of coliforms and the levels required by the Drinking Water Standards, using the QUAL2E water quality model. The principal factors adversely affecting water quality were discharges from the 4 principal sewage treatment plants and runoff from the irregular settlements; industrial activities in the catchment had no major effect. Modelling runs for predicting faecal coliform counts demonstrated that bacterial die-off did not exert any significant beneficial effect on water quality.