M.Sc. (Aquatic Health) / Located largely in a semi-arid part of the world, South Africa’s water resources, in global terms are extremely scarce and limited. (South Africa is one of the 30 driest countries of the world). South Africa is already categorised as water stressed with annual freshwater availability of less than 1700 mm³ /person (the index for water stress) (Blignaut and Van Heerden, 2009). South Africa is a water scarce country due to low rainfall (less than 500 mm per annum, some parts less than 200 mm: the average of 475 mm is well below the global average of 860 mm p/a.) and due to the uneven distribution of its water resources (more than 60% of the river flow arising from only 20% of the land area) which is a direct result of the climate and topography of the country (Davis and Day, 1998). South Africa is a large piece of land, far larger than for instance Germany (population of 82.7 million- Bergman and Renwick, 2003). When compared, Germany has 2169 cubic meters of water available per person while South Africa has only 1208 (Bergman and Renwick, 2003). Compared with another arid country, Australia has a population of 19.1 million and freshwater resources of 18 722 cubic meters per person (Bergman and Renwick, 2003). South Africa has close to the lowest conversion of rainfall to usable run-off from rivers of all the countries in the world (South Africa 8.6%, Australia 9.8%, and Canada 66%) (Bergman and Renwick, 2003). South Africa will also be negatively impacted by both changes in climate and the prevalence and spread of alien invasive species (Blignaut and Van Heerden, 2009). Prosperity for South Africa depends upon the sound management and utilisation of many resources, with water playing a pivotal role. Any decrease in the quality and therefore the usability of water in South Africa by 1% may result in the loss of 200 000 jobs, a drop of 5.7% of disposable income per capita, and an increase of 5% or R18.1 billion in government spending. This will further result in a 1% decrease in the GDP growth rate (Du Toit, 2010). This is reiterated by a number of other studies.

Freshwater resources and supplies in South Africa are experiencing severe stress from rising population growth, drought and high urbanization. The stress factors have also exerted pressure on wastewater treatment works leading to the release of partially treated effluent. The study assessed and compared the impact of the two wastewater treatment works effluent discharged into the Roodeplaat Dam. Selected physical parameters (pH, conductivity), chemical parameters (total oxidised nitrogen, phosphate, chemical oxygen demand, chloride, sulphate, sodium) and microbiological parameter (Escherichia coli) were evaluated and compared with South African standards. Secondary data (from January 2012 to December 2017) was used to identify parameters that were above or below regulatory standards. The t-test (p < 0.05) was used to compare changes between 2012 and 2018 over the same months.The results indicated that aquatic ecosystem quality has not improved, degradation continues as well as a lack of intervention from authorities. The leading parameters in causing stress to Roodeplaat water quality in descending order were Escherichia coli (E. coli), Phosphate (PO43-), Total Oxidized Nitrogen (TON), Chemical Oxygen Demand (COD), Chlorophyll a (Chl a), Ammonia (NH3), Electrical Conductivity (EC) and Sodium (Na). One of the main reasons why poor effluent was released is limited financial investment to upgrade the treatment facilities. This research provided highlights on the need to enforce extra measures to guarantee compliance of treated effluent quality to the existing guidelines. Moreover it highlights the need for concerned department’s authorities to invest in water by allocating enough budget to address the challenge of wastewater treatment works upgrades. / Environmental Sciences / M. Sc. (Environmental Sciences)