Fluctuations of indicator and index microbes as indication of pollution over three years in the Plankenburg and Eerste Rivers, Western Cape, South Africa

The Plankenburg and Eerste Rivers (Western Cape) have been reported to be contaminated with faecal coliforms. Water is drawn from both rivers for irrigation of fresh produce. The potential risk in the use of these rivers as irrigation sources was assessed by determining the fluctuations of ‘indicator’ and ‘index’ microbes over 3 years. Selected physico-chemical (water temperature, pH, COD, conductivity and alkalinity) and microbiological parameters, including coliforms, faecal coliforms, Escherichia coli and enterococci, as ‘indicators’ of faecal pollution, and Salmonella, Listeria and Staphylococcus, as ‘index’ of the presence of potential pathogens, were monitored.No correlation was found between water temperature and COD (r2 = 0.0003), whereas for temperature and pH a significant trend (p = 0.0004), but low correlation (r2 = 0.108), was observed. With the exception of the faecal coliforms (E. coli), no significant trends and no correlations between temperature and the dependent variables were found. For the faecal coliforms there was a significant trend (p = 0.0289) with temperature but not a good correlation (r2 = 0.0434), but the impact of temperature over time was significant (p = 0.0047). This is important, when the World Health Organisation (WHO) and South African Department of Water Affairs (DWA) guidelines for faecal coliforms are applied, as it indicates that temperaturedoes impact the faecal coliform numbers. The presence of indicator organisms did not only indicate unsanitary conditions, but also the presence of potential pathogens such as Staphylococcus, Klebsiella, Listeria and Salmonella. Based on these results the microbial quality of these rivers was found to be unacceptable and does not meet the WHO and DWA guidelines for safe irrigation. There was also a high risk of exposure to human pathogens when water from these rivers is used to irrigate produce that is consumed without further processing.Keywords: Irrigation water, faecal pollution, indicator and index organisms, Plankenburg and Eerste River

UASB treatment of a highly alkaline fruit-cannery lye-peeling wastewater

Anaerobic treatment of a highly alkaline fruit-cannery lye-peeling wastewater was investigated, using an upflow anaerobic sludge blanket (UASB) reactor. Only a short initialisation period was required before COD reduction and OLR had stabilised at 85 to 90% and 2.40 kgCODEm-3Ed-1, respectively. With subsequent increases in OLR to 8.1 kgCODEm-3Ed-1, the COD reduction remained between 85 and 93% and biogas production peaked at 4.1 .Ed-1 (63% methane). COD and reactor pH started to decrease after 111 d. Decreases in gas production were observed by Day 102, decreasing to 2.48 .Ed-1 by Day 111 and 0.93 .Ed-1 after 129 d. Subsequent reductions in the OLR, by reducing influent COD, had no effect on reactor stability. Loss of reactor performance was ascribed to the accumulation of sodium (potentially > 20 000 mgE.-1) within the reactor biomass, leading to inhibition of methanogenesis

Underestimated pathways of infection: Effects of contaminated irrigation water on fresh fruit and vegetables

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Quantitative investigation into the link between irrigation water quality and food safet, volume III: Impact of environmental parameters on growth kinetics of contaminants

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Treatment of apple and wine processing wastewaters using combined USAB technology and ozonation scenarios.

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Use of ozone and hydrogen peroxide in the post-treatment of UASB treated alkaline fruit cannery effluent.

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Combining UASB technology and advanced oxidation processes (AOP's) to treat food-processing wastewaters.

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Quantitative investigation into the link between irrigation water quality and food safety, volume I: Synthesis report

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Quantitative investigation into the link between irrigation water quality and food safety, volume IV: Extent of contamination in irrigation water and links to irrigated produce at-harvest: with a further exploratory study of contamination of fresh produce at point-of-retail

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Kinetic optimisation of the reversed phase liquid chromatographic separation of rooibos tea (<I>Aspalathus linearis</I>) phenolics on conventional high performance liquid chromatographic instrumentation

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