Browsing by Author "Cloete, T. E."

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    Evaluating sulphate removal and identifying the bacterial community present in acid mine drainage treated with synthetic domestic wastewater sludge
    (South African Water Research Commission, 2016-07) Van den Berg, M. F.; Botes, M.; Slabbert, E.; Cloete, T. E.
    Domestic wastewater sludge can serve as a carbon source in the passive biotic treatment of acid mine drainage (AMD) in microbial bioreactors to create anaerobic conditions for the removal of sulphate, chemical oxygen demand (COD) and pH neutralization. A synthetic medium simulating domestic wastewater sludge was used in AMD treatment in a ratio of 1:1 AMD: synthetic domestic wastewater sludge (SDWWS). Sulphate and COD removal were determined at different incubation temperatures and with and without a biofilm in the bioreactors. Sulphate and COD were removed by 60.8% and 96% within 26 d, after which a plateau was reached. Bacterial community analyses using next generation sequencing showed that Chlorobium spp. dominated at a relative percentage of 36% followed by Magnetospirillum spp. and Ornithobacterium spp. The effect of a resident biofilm in the bioreactors showed dominance of Chlorobium spp. at a relative percentage of 62% and removal of sulphates and COD at 96% and 58%, respectively, after 26 d. Incubation at 17–19°C reduced sulphates by only 10% and COD by 12% after 17 d, after which a plateau was reached. Magnetospirillum spp. was the dominate organism at the end of this trial.
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    Influence of winemaking practices on the characteristics of winery wastewater and water usage of wineries
    (South African Society for Enology and Viticulture, 2014) Conradie, A.; Sigge, G. O.; Cloete, T. E.
    The winemaking industry produces large volumes of wastewater that pose an environmental threat if not treated correctly. The increasing numbers of wineries and the demand for wine around the world are adding to the growing problem. The vinification process includes all steps of the winemaking process, from the receipt of grapes to the final packaged product in the bottle. To fully understand all the aspects of winery wastewater it is important to know the winemaking processes before considering possible treatments. Winemaking is seen as an art and all wineries are individual, hence treatment solutions should be different. Furthermore, wastewater also differs from one winery to another regarding its volume and composition and therefore is it vital for a detailed characterisation of the wastewater to fully understand the problem before managing it. However, prevention is better than cure. There are a number of winemaking practices that can help lower the volume of the wastewater produced to decrease the work load of the treatment system and increase the efficiency of treatment.