There has been a steady rise in antibiotic resistance of bacteria and this urgently calls for the discovery of alternative therapeutic agents. Honey possesses therapeutic potentials which includes antimicrobial activity. Although the... more
There has been a steady rise in antibiotic resistance of bacteria and this urgently calls for the discovery of alternative therapeutic agents. Honey possesses therapeutic potentials which includes antimicrobial activity. Although the antimicrobial activity of honey has been effectively established against an extensive spectrum of microorganisms, it differs depending on the type of honey. To date, not much extensive studies of the antibacterial properties of South African honeys on enteric microorganisms have been conducted. The objective of this study was to compare the antibacterial activity of extracts of six different honeys with those of medical plants commonly used in South Africa. Using a broth dilution method, the antibacterial activity extracts of six South African honeys and medicinal plants against six enteric microorganisms viz- Enterobacter cloacae, Escheriachia coli, Klebsiella pneumoniae, Citrobacter freundii isolated from geophagia samples and Aeromonas hydrophila and...
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The relationship between protozoan biomass concentration and phosphate and nitrate removal was investigated in mixed liquor using three different carbon sources as supplements. The study was carried out using three respective initial... more
The relationship between protozoan biomass concentration and phosphate and nitrate removal was investigated in mixed liquor using three different carbon sources as supplements. The study was carried out using three respective initial biomass concentrations in a shaking flask environment. Samples were taken every 24 h to determine phosphate, nitrate, dissolved oxygen and chemical oxygen demand. The results revealed a direct relationship between decreases in nutrient concentrations and increases in cell densities of the isolates. Between 24 and 96 h, the increases in the protozoan density corresponded to a phosphate decreases from initial ranges of 55.42-57.36 mg/L, 50.27-51.17 mg/L and 50.01-50.83 mg/L to final ranges of 2.46-11.90 mg/L, 0.61-11.80 mg/L and 1.29-13.89 mg/L, in the presence of Aspidisca, Trachelophyllum and Peranema, respectively. Nitrate concentrations were observed to decrease from initial ranges of 23.84-25.90 mg/L, 23.94-25.84 mg/L and 26.12-26.54 mg/L to final ranges of 0.11-6.32 mg/L, 0.16-5.60 mg/L and 0.24-9.04 mg/L, respectively. The study had revealed that an increase in cell density of the test isolates produces a corresponding increase in phosphate and nitrate removal.
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The relationship between biomass concentration to nutrient and chemical oxygen demand (COD) removal in mixed liquor supplemented with sodium acetate was investigated, using three protozoan isolates and three different initial biomass... more
The relationship between biomass concentration to nutrient and chemical oxygen demand (COD) removal in mixed liquor supplemented with sodium acetate was investigated, using three protozoan isolates and three different initial biomass concentrations (10(1), 10(2) and 10(3) cells/mL). The study was carried out in a shaking flask environment at a shaking speed of 100 rpm for 96 h at 25 degrees C. Aliquot samples were taken periodically for the determination of phosphate, nitrate, COD and dissolved oxygen, using standard methods. The results revealed remarkable phosphate removal of 82-95% at biomass concentration of 10(3)cells/mL. A high nitrate removal of over 87% was observed at all initial biomass concentration in mixed liquor. There was an observed COD increase of over 50% in mixed liquor in at the end of 96-h incubation and this was irrespective of initial biomass concentration used for inoculation. The study shows the trend in nutrient and COD removal at different biomass concentrations of the test isolates in mixed liquor.
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ABSTRACT Increasing demand for safe drinking water and the problems associated with some existing water treatment methods have made it vital for the development of new technologies to address these challenges. This study explores the use... more
ABSTRACT Increasing demand for safe drinking water and the problems associated with some existing water treatment methods have made it vital for the development of new technologies to address these challenges. This study explores the use of nanosized silver and copper impregnated on polyurethanes for possible use in water disinfection. It also investigates the adsorption of organics by the metal impregnated polyurethanes in water. Copper and silver nanoparticles were immobilized on carbon nanotube and embedded in water-insoluble cyclodextrin polyurethane polymers. The polyurethanes were characterized by various techniques such as BET, TEM, SEM and EDX and evaluated for their adsorption and bacteria reduction capacity using spiked water samples containing bacteria (Escherichia coli and Salmonella typhi) and a model organic pollutant (para-nitrophenol) in water. The metal impregnated polyurethanes inactivated up to 3 logs of bacteria but had a maximum adsorption of 55% of the model organic pollutant.
Research Interests: Environmental Engineering, Chemical Engineering, Civil Engineering, Microbiology, Chemistry, and 15 moreModeling, Nanoparticle, Scanning Electron Microscopy, Carbon Nanotubes, Carbon Nanotube, Nanoparticles, Adsorption, New Technology, Copper, Escherichia coli, Bacteria, Drinking Water, Silver Nanoparticle, Decontamination, and Salmonella Typhi
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The demand of crude oil or any other oil by-products across the world and various activities are such as human and industrial activities has led to continuous pollution of various existing fresh water. The study was conducted using three... more
The demand of crude oil or any other oil by-products across the world and various activities are such as human and industrial activities has led to continuous pollution of various existing fresh water. The study was conducted using three protozoan isolates (Aspidisca sp., Trachelophyllum sp. and Peranema sp) where their growth and biodegradation abilities were screened using crude oil spill rich polluted wastewater in shaking flasks at pH 8 and incubated at 30 °C with a speed of 100 rpm for 5 days. Chemical Oxygen Demand, Dissolved Oxygen and growth of protozoan isolates were determined using standard methods. Crude oil concentrations in the samples were analysed using partition gravimetric method. The study revealed that high amount of COD released and over 80% DO were removed from wastewater. The protozoan biomass of 1.00×10 cells/mL was able to degrade crude oil (initial concentration:<50 mg/L) from wastewater at average rates ranging from 10.41% to 55.5%, from 11.0% to 64.5%,...
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The study investigates the influence of process parameters on the effectiveness of ozonation in the removal of organic micro-pollutants from wastewater. Primary and secondary municipal wastewater containing phenol was treated. The effect... more
The study investigates the influence of process parameters on the effectiveness of ozonation in the removal of organic micro-pollutants from wastewater. Primary and secondary municipal wastewater containing phenol was treated. The effect of operating parameters such as initial pH, ozone dosage, and initial contaminant concentration was studied. An increase in contaminant decomposition with pH (3–11) was observed. The contaminant removal efficiencies increased with an increase in ozone dose rate (5.5–36.17 mg L−1 min−1). Furthermore, the ultraviolet absorbance (UV 254 nm) of the wastewater decreased during ozonation indicating the breakdown of complex organic compounds into low molecular weight organics. Along the reaction, the pH of wastewater decreased from 11 to around 8.5 due to the formation of intermediate acidic species. Moreover, the biodegradability of wastewaters, measured as biological and chemical oxygen demand (BOD5/COD), increased from 0.22 to 0.53. High ozone utilizati...
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The failure of wastewater treatment plants to produce effluents of a high microbiological quality is a matter of great concern in terms of water resource pollution. A more serious concern is that this water source is used by communities... more
The failure of wastewater treatment plants to produce effluents of a high microbiological quality is a matter of great concern in terms of water resource pollution. A more serious concern is that this water source is used by communities in developing countries for multiple purposes, which include drinking, recreation and agriculture. The current study investigated the prevalence and potential health risks of enteropathogenic bacteria (Salmonella typhimurium, Shigella dysenteriae and Vibrio cholerae) in the treated effluents of three selected South African Wastewater Treatment Works as well as their receiving water bodies. Culture-based and polymerase chain reaction techniques were used to detect and identify the pathogenic bacteria. The conventional methods revealed that of the 272 water samples collected, 236 samples (86.8%) tested presumptively positive for Salmonella spp., 220 samples (80.9%) for Shigella spp. and 253 samples (93.0%) for V. cholerae. Molecular test results indica...
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In developing countries, most people do not have access to adequate water supply services, and the receiving water bodies are used for various purposes. Treated sewage effluent should therefore comply with a standard of nil fecal... more
In developing countries, most people do not have access to adequate water supply services, and the receiving water bodies are used for various purposes. Treated sewage effluent should therefore comply with a standard of nil fecal coliforms/100 ml before its discharge into the receiving surface water body, and this standard can only be achieved by disinfection. The present study aimed at evaluating the efficiency of four wastewater treatment plants for the removal of coliforms in order to establish the relationship between the microbiological quality of the final effluent and that of the receiving water body, which may influence infections and diseases in the community of the Eastern Cape Province, South Africa. The disinfection practice in terms of chlorine residual concentrations was found not to be sufficient for the removal of coliforms from the effluent. The Dimbaza plant removed coliform organisms at 85.71%. In Alice, Fort Beaufort, and East London wastewater treatment plants, 62.5%, 60%, and 43% of the organisms found in treated final effluents were also prevalent in receiving water bodies, respectively. The results suggest that the microbiological quality of the effluents examined pose a serious health risk to the communities because various potentially pathogenic organisms were identified. Keywords: treatment; wastewater; coliforms; receiving water body; developing country
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This study compared the effectiveness and sustainability of five selected cost-effective home water treatment systems in removing Cryptosporidium and Giardia spp. from water sources. These systems included: silver impregnated porous pot... more
This study compared the effectiveness and sustainability of five selected cost-effective home water treatment systems in removing Cryptosporidium and Giardia spp. from water sources. These systems included: silver impregnated porous pot (SIPP), biosand filter combined with zeolite (BSF-Z), biosand filter without zeolite (BSF-S), bucket filter (BF) and ceramic candle filter (CCF). The USEPA Methods 1623 were used for the isolation and the detection of the protozoan parasites. The flow rates of the devices ranged between 0.05 and 160.5 L/h. The average turbidity of the environmental intake water samples ranged between 1.47 and 42.93 NTU before filtration and between 0.05 and 14.49 NTU after filtration. The performance of the SIPP in removing the parasites (98–100% of both oocysts and cysts from synthetic water; 96–99.6% oocysts and 96.6–99.8% cysts from the environmental water sources) and in removing viral indicator (97.7–100%) was found to be significantly higher (p < 0.05) compa...
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To evaluate the effectiveness of polydex for the removal of total coliforms (TC), fecal coliforms (FC), and presumptive Salmonella (PS), three types of water sources were considered, which included raw water from a river, filtered surface... more
To evaluate the effectiveness of polydex for the removal of total coliforms (TC), fecal coliforms (FC), and presumptive Salmonella (PS), three types of water sources were considered, which included raw water from a river, filtered surface water, and groundwater. The water samples were treated with two different doses of polydex: 3.9 mg/l and 5.4 mg/l. The dose of 3.9 mg/l appeared to be suitable for the disinfection of filtered surface water and groundwater samples with turbidity values ranging between 0.59 and 8.18 NTU. In these water samples, no coliforms were detected 5 h after disinfection, and the copper residuals ranged between 1.01 and 2.96 mg/l 7 h after disinfection. The results revealed that the dose of 3.9 mg/l was not sufficient for the disinfection of highly turbid waters (>9 NTU). A dose of 5.4 mg/l used for the disinfection of these waters completely removed coliform bacteria 7 h after disinfection, and the copper residual in the finished water ranged between 2.52–3.06 mg/l. Although this study has revealed the effectiveness of polydex as a disinfectant, its efficiency may vary with the turbidity of water source. For turbid water, it is recommended that the dose of polydex be higher than the one recommended by the manufacturer. Keywords: disinfection; polydex; bactericidal; drinking water; rural community
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We report the aqueous hydrothermal preparation technique of Ag impregnated indigenous natural clinoptilolite zeolites (NCZ) and sand as a cost effective approach for microbial remediation of rural and small community water supplies in... more
We report the aqueous hydrothermal preparation technique of Ag impregnated indigenous natural clinoptilolite zeolites (NCZ) and sand as a cost effective approach for microbial remediation of rural and small community water supplies in South Africa. Substrates were saturated with ...
This paper is focused on primary, secondary, and total efficiency evaluation of the wastewater treatment process for chosen small wastewater treatment plant (WWTP) located near the Moravian Karst. Eight wastewater samples were taken... more
This paper is focused on primary, secondary, and total efficiency evaluation of the wastewater treatment process for chosen small wastewater treatment plant (WWTP) located near the Moravian Karst. Eight wastewater samples were taken during one year in three sampling profiles of WWTP: biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), pH, ammonia nitrogen (N-NH4), nitrite nitrogen (N-NO2), nitrate nitrogen (N-NO3), inorganic nitrogen (Ninorg), total phosphorus (Ptotal). Treatment efficiency by reduction was calculated for all laboratory analyzed indicators and average values were determined for the whole period. Calculated treatment efficiency of indicators BOD, COD and suspended solids was compared with the permissible minimum treatment efficiency of discharged waste water by Government Regulation No. 61/2003 Coll., for the WWTP from 500 to 2 000 PE. Permissible minimum treatment efficiency is not legislatively determined for the primary and second...
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This study was undertaken to highlight the social disparity between rural and urban areas in terms of housing patterns, provision of safe drinking water, access to sanitation facilities, education, employment rate and health-related to... more
This study was undertaken to highlight the social disparity between rural and urban areas in terms of housing patterns, provision of safe drinking water, access to sanitation facilities, education, employment rate and health-related to diarrhoeal episodes in Ugu District Municipality of KwaZulu-Natal Province of South Africa. To achieve this aim, a survey was conducted using a structured questionnaire. Drinking water samples were collected from the point of supply and the storage containers to assess the microbiological quality of drinking water in both rural and urban areas. Results of this study revealed prominent residential segregation between rural and urban communities, whereby the houses in the rural areas were generally constructed with corrugated iron sheets, or mud brick and mortar whereas conventional brick-and-mortar construction was used to build those in the urban areas. All of the urban households had flush toilets in their houses (100%), while 98.2% of the rural hous...
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The presence of antibiotic-resistant Salmonella spp. in the environment is of great public health interest, worldwide. Furthermore, its extended-spectrum β-lactamase (ESBL)-producing strains constitute an emerging global health concern... more
The presence of antibiotic-resistant Salmonella spp. in the environment is of great public health interest, worldwide. Furthermore, its extended-spectrum β-lactamase (ESBL)-producing strains constitute an emerging global health concern due to their limited treatment options in hospital. Therefore, this study aimed at characterising and tracking nonresistant and ESBL–producing Salmonella spp. from agricultural settings to nearby water sources highlighting their antibiotic resistance genes (ARG) and virulence factor (VF) distribution using a combination of both culture-dependent and independent methods. Furthermore, this study investigated the diversity and shared serovars among sampled matrices using amplicon sequencing of the invasion gene A (invA) of Salmonella spp. The results showed that soil had the highest prevalence of Salmonella spp. (62.5%, 65/104) and ESBL-producing Salmonella (34.6%, 36/104). For typed ARG, the most commonly detected gene was blaOXA with 75% (30/40), follo...
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The environmental dissemination of selected antibiotics from hospital wastewater into municipal wastewater and lastly to a receiving water body was investigated. Selected antibiotics (azithromycin (AZM), ciprofloxacin (CIP), clindamycin... more
The environmental dissemination of selected antibiotics from hospital wastewater into municipal wastewater and lastly to a receiving water body was investigated. Selected antibiotics (azithromycin (AZM), ciprofloxacin (CIP), clindamycin (CDM), doxycycline (DXC) and sulfamethoxazole (SMZ)) present in effluents of academic hospital wastewater, influents, sewage sludge, and effluents of municipal wastewater, receiving water, and its benthic sediment samples were quantified using the Acquity® Waters Ultra-Performance Liquid Chromatography System hyphenated with a Waters Synapt G2 coupled to a quadrupole time-of-flight mass spectrometer. The overall results showed that all assessed antibiotics were found in all matrices. For solid matrices, river sediment samples had elevated concentrations with mean concentrations of 34,834, 35,623, 50,913, 55,263, and 41,781 ng/g for AZM, CIP, CDM, DXC, and SMZ, respectively, whereas for liquid samples, hospital wastewater and influent of wastewater ha...
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The current study investigated the acceptance rate and long-term effectiveness of cost-effective household water treatment systems deployed in Makwane Village. A structured questionnaire was used prior to implementation to collect... more
The current study investigated the acceptance rate and long-term effectiveness of cost-effective household water treatment systems deployed in Makwane Village. A structured questionnaire was used prior to implementation to collect information such as level of education, level of employment, and knowledge about point-of-use water treatment systems in the target area. The long-term effectiveness was determined by factors such as the Escherichia coli removal efficiency, turbidity reduction, silver leached, and flow rate of the household water treatment devices. The results of the survey prior to deployment revealed that only 4.3% of the community had a tertiary qualification. Moreover, 54.3% of the community were unemployed. The results further revealed that 65.9% of the community were knowledgeable about other point-of-use water treatment methods. The acceptance rate, which was found to be initially higher (100%), reduced after three months of implantation (biosand filter with zeolite...
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Microbial water pollution is a key concern leading to waterborne diseases. This study evaluated the disinfection of wastewater using ozonation. The following aspects were investigated: inactivation efficiency against Escherichia coli,... more
Microbial water pollution is a key concern leading to waterborne diseases. This study evaluated the disinfection of wastewater using ozonation. The following aspects were investigated: inactivation efficiency against Escherichia coli, Salmonella species, Shigella species, and Vibrio cholerae; modelling of inactivation kinetics using disinfection models; and evaluation of microbial regrowth studies. 99% bacterial inactivation was obtained within 15 min, irrespective of the water matrix, showing the strong oxidizing potential of ozone. The disinfection data were fitted into the log-linear and Weibull models. The survival curves were non-linear and fitted the Weibull model (fractional bias and normalized mean square error equal to 0.0), especially at high bacterial concentrations (106 CFU/mL). The inactivation occurred in two stages: an initial rapid stage (15 min) and a final slow stage exhibiting a tailing mechanism (15-45 min) probably as a result of the self-defence mechanisms adop...
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To investigate the effect of a combined chlorine-monochloramine disinfection process on the inhibition of biofilm regrowth, surface water and groundwater were used as the test water sources while stainless steel and galvanized mild steel... more
To investigate the effect of a combined chlorine-monochloramine disinfection process on the inhibition of biofilm regrowth, surface water and groundwater were used as the test water sources while stainless steel and galvanized mild steel were used for the study of biofilm regrowth in a laboratory-scale unit. Disinfection was carried out using 2.5 mg.L-1 chlorine followed by 1.5 mg.mg.L-1 monochloramine. The bactericidal effectiveness of the process relied on heterotrophic plate count (HPC) and total bacteria. The concentrations of organic and inorganic compounds such as dissolved organic carbon, calcium, magnesium, chemical oxygen demand, total nitrogen, phosphate and sulfate were also taken into account. The formation of biofilm occurred 24 h after the exposure of test pipe materials to both chlorinated surface water and groundwater (with the average counts of 2 log.cfu.cm-2 for viable bacteria in both systems, 5 log.cells.cm-2 and 6 log.cells.cm-2 in surface water and groundwater ...
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This aim of this study was to ascertain whether household container-stored drinking water might play a role in the diarrhoeic conditions of HIV/AIDS patients and non-HIV-infected individuals of the rural communities who attended the Ugu... more
This aim of this study was to ascertain whether household container-stored drinking water might play a role in the diarrhoeic conditions of HIV/AIDS patients and non-HIV-infected individuals of the rural communities who attended the Ugu District Municipal hospitals. Water samples were collected from the standpipes and household containers, and stool specimens were obtained from HIV/AIDS-positive and non-HIV/AIDS patients with diarrhoea. Significant correlations were established between the incidence of potentially pathogenic bacteria isolated from chlorinated household-stored water, and in stool specimens of HIV-positive patients with diarrhoea (r = P < 0.05). A combination of molecular analysis targeting the 16S rRNA gene and the restriction fragment length polymorphism and sequence analysis of the amplified gene for differentiating between species and strains of the bacterial pathogens was also applied to isolates obtained from stored-water samples and stool specimens. Similar ...