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The failure of South African wastewater treatment plants to produce effluents of a high microbiological quality is a matter of great concern in terms of the pollution of water resources. This study aimed at assessing the effectiveness of 4 wastewater treatment plants in the Gauteng Province, namely the Zeekoegat, Baviaanspoort, Rayton and Refilwe Water Care Works (WCW), in the removal of pathogenic bacteria and viral indicators. Also taken into consideration were free chlorine concentrations and turbidity levels, which were measured using standard methods. Conventional methods and/or polymerase chain reaction (PCR) techniques were used to detect and identify pathogenic bacteria and coliphages. The turbidity ranged from 2.39 to 62.40 NTU and the concentrations of free chlorine ranged from 0.03 tol.60 mg·ℓ-1 for all plants. Despite high free chlorine residual concentrations in treated effluents, the survival and occurrence of Escherichia coli, Salmonella typhimurium and Vibrio cholerae were significantly higher at Baviaanspoort (100%, 88.2% and 35.3%), Refilwe (87.5%, 59.4% and 2 1.9%) and Rayton (75%, 38.2% and 9.4%) compared to Zeekoegat, which only showed the survival of E. coli, at a much lower occurrence rate of 8.8%. Somatic and F-RNA coliphages were removed at 15.57% and 13.96% for Baviaanspoort, 11.62% and 22.42% for Refilwe, 25% and 32.10% for Rayton, and 40.41% and 52.57% for Zeekoegat WCW. Significant correlations were found between pathogenic bacteria and coliphages at all plants (r = 0.765 for Baviaanspoort, r = 0.904 for Zeekoegat, r = 0.680 for Refilwe, r = 0.796 or the Rayton WCW, p <0.01). A combination of sedimentation, rapid sand filtration and chlorination processes was found to be a major prerequisite for the reduction of turbidity levels and viral indicators and the successful removal of pathogenic bacteria in the Zeekoegat WCW. This study therefore suggests an upgrading of the wastwater treatment plants by including processes such as rapid sand filtration and UV disinfection, which have proved to be effective in the removal and inactivation of pathogenic bacteria and viruses. [ABSTRACT FROM AUTHOR]

This study aimed at assessing the effectiveness of 4 wastewater treatment plants of the Gauteng Province, namely Zeekoegat, Baviaanspoort, Rayton and Refilwe Water Care Works (WCW), in the removal of Cryptosporidium and Giardia (oo)cysts. Wastewater influent and treated effluent samples were taken weekly between January and April 2008. Cryptosporidium and Giardia (oo)cysts were detected by immunofluorescence and immunomagnetic separation, according to a modified US EPA 1623 method. Effluent samples were subjected to a molecular study for the identification of Cryptosporidium parvum Genotype I and Giardia lamblia Assemblage A. The 18S rRNA gene for restriction digests was therefore used to characterise these (oo)cysts. Cryptosporidium oocysts were repeatedly detected in effluent samples collected from all wastewater treatments at lower concentration (range <1 to 40 oocysts/L) levels than Giardia cysts (range <1 to 175 cysts/ℓ). The mean removal efficiencies of Cryptosporidium and Giardia at the 4 wastewater treatment plants ranged from 67.40% to 98.26% and from 86.81% to 99.96%, respectively. For all effluent samples, except Zeekoegat WCW, 29% and 41% contained oocysts of Cryptosporidium parvum Genotype I and cysts of Giardia lamblia Assemblage A, respectively. Both C. Parvum and G. lamblia are human pathogens. This stresses the potential risk of discharging these parasites into receiving water bodies. [ABSTRACT FROM AUTHOR]

Silver impregnated carbon nanotubes and cyclodextrin polymers were synthesised by first functionalising carbon nanotubes in a mixture of nitric and sulphuric acid before impregnating them with silver nanoparticles. The silver impregnated functionalised carbon nanotubes were then polymerised with β cyclodextrin using hexamethylene diisocyanate as the linker. The polymers were characterised using various techniques. The polymers were then tested for their ability to destroy bacteria in water and were found to reduce bacterial cell counts in water spiked with E. coli (ATCC 25925) to as low as zero cfu/mℓ. Furthermore, the polymers could absorb 58% of para-nitrophenol from water spiked with this organic compound, which is a known pollutant in water. [ABSTRACT FROM AUTHOR]

In an endeavour to ascertain the interplay of factors involving chlorine dose, turbidity and flow capacity on microbial quality of drinking water in small water treatment plants (SWTPs), data from a previous study were analysed. The findings showed that most of the SWTPs were not producing water of safe microbial quality. Fifty one percent (51%) and seventy three (73%) of the SWTPs were below the stipulated limits for residual chlorine in final water and water at the point of use respectively. Current flow capacity was a major determinant of the microbial water quality indicators but no association was found between the dose of chlorine used for water treatment and the microbial water quality indicators. However, a combination of the amount of chlorine dose used up during treatment, flow capacity and change in turbidity contributed to about 65% of the amount of heterotrophic plate counts removed from raw water. Current flow capacity contributed less than 14% of the variation in chlorine dose used in water treatment at the plants. Turbidity tended to correlate and contribute more to the prediction of total coliform counts while faecal coliform counts were determined by current flow capacity and conductivity. Treatment plants with current flow capacity of over 50 Ml/d tended to be more efficient in heterotrophic plate count removal. In conclusion, this study noted that most of the SWTPs were using a chlorine dosage that was below the amount required by their respective current flow capacity; possible micro-organism resistance to chlorine and the significant effect of the level of turbidity on the microbial quality of treated water. [ABSTRACT FROM AUTHOR]

Aim: The current study investigated the prevalence and molecular relatedness between Escherichia coli O157:H7 isolated from water, meat and meat products and vegetables and from stools of confirmed and non-confirmed Human Immune Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) patients with diarrhoea. Methods and Results: Culture-based and polymerase chain reaction techniques were used to identify E. coli O157:H7. Thirty-five per cent of meat products, 25·5% of water, 21·7% of vegetables as well as 56·5% and 43·5% of stools of confirmed and non-confirmed HIV/AIDS patients, respectively, were presumptively positive with E. coli O157. Molecular results indicated that 10·3%, 8·6% and 7·8% of the vegetables, water and meat products examined carried E. coli O157:H7, which had homologous fliC H7, rfbE O157 and eaeA genetic loci to the genes of some E. coli O157:H7 isolated from 12·2% and 8·8% of the stools of confirmed and non-confirmed HIV/AIDS patients, respectively. Conclusions: Water, meat and meat products and vegetables are potential sources of E. coli O157:H7 that are potentially capable of causing diarrhoea in humans especially HIV/AIDS patients. Significance and Impact of the Study: Great care should be exercised to ensure that water and foods consumed by HIV/AIDS patients are safe, as contaminated water and foods can cause secondary infections in these patients. [ABSTRACT FROM AUTHOR]

Fresh vegetables have been implicated in outbreaks of Escherichia coli O157:H7 in most parts of the world. Microbiological quality of vegetables used as recipes for salads is very crucial. Residents of the Amathole District in the Eastern Cape Province of South Africa consume salads frequently, although the microbial quality of recipe vegetables is questionable. The present study investigated the prevalence and antimicrobial susceptibility of E. coli O157:H7 isolated from selected vegetables sold within the Amathole District. One hundred eighty samples of the vegetables were analyzed. Strains of E. coli O157:H7 were isolated by enrichment culture and by immunomagnetic separation and identified by conventional and molecular techniques. In three settlements in this district, the mean counts of presumptive E. coli O157 for the vegetables ranged between 9 x 10³ and 1.6 x 106 CFU/g for Fort Beaufort, 1.6 x 10³ and 1.6 x 105 CFU/g for Mdantsane, and 1.3 x 10³ and 4.1 x 104 CFU/g for Alice. Four (10.3%) of 39 vegetable samples were confirmed to carry E. coli O157:H7. Four representative E. coli O157:H7 isolates from these vegetables were susceptible to at least one of the eight antimicrobial agents tested against them. Even though the prevalence of E. coli O157:H7 was low and those isolated were susceptible to most of the antimicrobials, there remains a need for E. coli O157:H7 surveillance in vegetables used in salad recipes in urban and rural areas of South Africa. [ABSTRACT FROM AUTHOR]

This study describes the chemical and microbiological analysis of municipal drinking water collected from five sites (Ntselamanzi, Davidson primary school, Victoria East Clinic, Hillcrest primary school and the University of Fort Hare) of the Alice water distribution system in the Eastern Cape province of South Africa. To indicate the microbiological quality of the drinking water produced by the Alice water treatment plant (AWTP), heterotrophic plate count bacteria (HPC), Salmonella species (SP), faecal coliforms (FC) and total coliforms (TC) were determined according to standard methods. Also measured were various chemical and physical properties including pH, temperature, turbidity, residual chlorine, fluoride, phosphate, chromium, sulphate, nitrate/nitrite, copper, cadmium, zinc, total hardness and chemical oxygen demand. The chemical quality of the drinking water was acceptable with the exception of turbidity, of which values ranged between 1.6 and 4.7 NTU according to location in the distribution system. High turbidity resulted in the absence of or low residual chlorine (less than 0.3 mg/l) concentrations in the water. The failure of the AWTP to protect the distribution system with sufficient residual chlorine resulted in the microbiological quality (HPC, 2.2 × 10³ -9.6 × 104 cfu/ml; SP, 0-29 cfu/100 ml; FC, 5-39 cfu/100 ml; TC, 7-209 cfu/100 ml) exceeding the standards for potable water. Aeromonas hydrophila, Escherichia coil, Serratia odorifera, Salmonella arizonae, Pseudomonas aeruginosa, Pseudomonas fluorescens, Serratia liquefaciens and Serratia marcescens were present in all water samples. There was the possibility of Vibrio species in the Victoria East Clinic water. The drinking water supplied by the AWTP therefore poses a threat to the health of consumers and calls for urgent intervention by local authorities. [ABSTRACT FROM AUTHOR]

The expected growth in nanomaterial applications could result in increased amounts of nanoparticles entering municipal sewer systems, eventually ending up in wastewater treatment plants and therefore negatively affecting microbial populations and biological nutrient removal. The aim of this study was to ascertain the impact of zinc oxide nanoparticles (nZnO) on the bacterial microbiome of an activated sludge system. A metagenomic approach combined with the latest generation Illumina MiSeq platform and RDP pipeline tools were used to identify and classify the bacterial microbiome of the sludge. Results revealed a drastic decrease in the number of operational taxonomic units (OTUs) from 27 737 recovered in the nZnO-free sample to 23 743, 17 733, and 13 324 OTUs in wastewater samples exposed to various concentrations of nZnO (5, 10 and 100 mg/L nZnO, respectively). These represented 12 phyla, 21 classes, 30 orders, 54 families and 51 genera, completely identified at each taxonomic level in the control samples; 7-15-25-28-20 for wastewater samples exposed to 5 mg/L nZnO; 9-15-24-31-23 for those exposed to 10 mg/L and 7-11-19-26-17 for those exposed 100 mg/L nZnO. A large number of sequences could not be assigned to specific taxa, suggesting a possibility of novel species to be discovered. [ABSTRACT FROM AUTHOR]

This study describes a unique partnership that reduced the risk of waterborne diseases associated with domestic water supplies in a typical rural water scheme in South Africa. A three-way collaboration between distant water-treatment experts, scientific staff and technical support from a nearby academic institution, and the previously untrained personnel from the rural municipal water treatment plant, proved to be a cost-effective option for the sustained provision of safe drinking water. This study points the way for similar projects elsewhere. [ABSTRACT FROM AUTHOR]

This paper describes a collaborative process of identifying and prioritising current and future water research questions from a wide range of water specialists within South Africa. Over 1 600 questions were collected, reduced in number and prioritised by specialists working in water research and practice. A total of 59 questions were finally proposed as an outcome of the study and are categorised under the themes of change, data, ecosystems, governance, innovation and resources. The questions range in scale, challenge and urgency, and are also aligned with prevailing paradigms in water research. The majority of the questions dealt with relatively short- to medium-term research requirements and most focused on immediate issues such as water supply, service delivery and technical solutions. Formulations of long-term research questions were sparse, partly because some of the principles and methods used in this study were difficult to apply in the South African context, and also because researchers are influenced by addressing what are believed to be the more immediate, short-term water-related challenges in South Africa. This is the first initiative of its kind to produce a comprehensive and inclusive list of research priorities for water in South Africa. [ABSTRACT FROM AUTHOR]

This study assessed the combined effects of V5+ and Ni2+ on metal-tolerant microbial isolates (bacteria: Bacillus licheniformis and Pseudomonas putida and Protozoa: Peranema sp. and Trachelophyllum sp). Using the primers for nccAC1 and van2 genes, the polymerase chain reaction technique revealed the presence of genes in both P. putida and Peranema sp., whereas B. licheniformis contained only nccAC1 and Trachelophyllum sp. none. P. putida appeared to be highly resistant to V5+ (growth rate: 0.43 h-1, LC10: 40-50 ppm-V5+) and Ni2+ (growth rate: 0.41 h-1, LC10: 50 ppm-Ni2+). The absence of target genes in Trachelophyllum sp. was then confirmed by its high sensitivity to V5+ (growth rate: 0.08 h-1, LC10: 40-ppm-V5+) and Ni2+ (growth rate: 0.04 h-1, LC10: 30-40 ppm-Ni2+) when compared to other test isolates. Although the combination of Ni2+ and V5+ resulted in a synergistic reaction by increasing their toxicity and impairing the microbial growth survival and their metal-removal ability in the wastewater systems, bacterial isolates were more persistent than protozoan isolates. P. putida were able to persist up to 60 h (4 CFU/mL, LC50: 40-50 ppm-V5+-Ni2+) and Peranema sp. up to 48 h (~4 Cells/mL, LC50: 30-40 ppm). However, the co-inoculation of bacterial (2x10²-6.6x106 CFU/mL, LC50: 40-50 ppm) and protozoan (2.01x10²-1.63x10³ Cells/mL, LC50: 30- 40 ppm) isolates decreased the synergistic effect of the test metals. This study suggests that the ability of microbial isolates to resist to the synergistic effect of Ni2+-V5+ was due to the presence of metal-resistant genes and the microbial diversity in the media. [ABSTRACT FROM AUTHOR]

Diarrhoea is a hallmark of HIV infections in developing countries, and many diarrhoea-causing agents are often transmitted through water. The objective of the study was to determine the diversity and antibiotic susceptibility profiles of bacterial organisms isolated from samples of household drinking-water consumed by HIV-infected and AIDS patients. In the present study, household water stored for use by HIV-positive patients was tested for microbial quality, and isolated bacterial organisms were analyzed for their susceptibility profiles against 25 different antibiotics. The microbial quality of water was generally poor, and about 58% of water samples (n=270) were contaminated with faecal coliforms, with counts varying from 2 colony-forming unit (CFU)/100 mL to 2.4x10⁴ CFU/100 mL. Values of total coliform counts ranged from 17 CFU/100 mL to 7.9x10⁵/100 mL. In total, 37 different bacterial species were isolated, and the major isolates included Acinetobacter lwoffii (7.5%), Enterobacter cloacae (7.5%), Shigella spp. (14.2%), Yersinia enterocolitica (6.7%), and Pseudomonas spp. (16.3%). No Vibrio cholerae could be isolated; however, V. fluvialis was isolated from three water samples. The isolated organisms were highly resistant to cefazolin (83.5%), cefoxitin (69.2%), ampicillin (66.4%), and cefuroxime (66.2%). Intermediate resistance was observed against gentamicin (10.6%), cefepime (13.4%), ceftriaxone (27.6%), and cefotaxime (29.9%). Levofloxacin (0.7%), ceftazidime (2.2%), meropenem (3%), and ciprofloxacin (3.7%) were the most active antibiotics against all the microorganisms, with all recording less than 5% resistance. Multiple drug resistance was very common, and 78% of the organisms were resistant to three or more antibiotics. Education on treatment of household water is advised for HIV-positive patients, and measures should be taken to improve point-of-use water treatment as immunosuppressed individuals would be more susceptible to opportunistic infections. [ABSTRACT FROM AUTHOR]