The prevention of outbreaks of waterborne diseases remains a major challenge to public health service providers globally. One of the major obstacles in this effort is the unavailability of on-line and real-time methods for rapid monitoring of faecal pollution to facilitate early warning of contamination of drinking water. The main objective of this study was to develop a β-glucuronidase (GUD)-based method that could be used for the on-line and real-time monitoring of microbial water quality. GUD is a marker enzyme for the faecal indicator bacteria Escherichia coli. This enzyme breaks down the synthetic substrate p-nitrophenyl-β-D-glucuronide (PNPG) to D-glucuronic acid and p-nitrophenol (PNP), which turns yellow under alkaline pH. The enzymatically produced PNP was used to detect GUD activity. In situ GUD assays were performed using running and stagnant water samples from the Bloukrans River, Grahamstown, South Africa. The physico-chemical properties of environmental GUD were determined, after which a liquid bioprobe and a microbial biosensor modified with Moraxella 1A species for the detection of the enzyme activity were developed. In order to determine the reliability and sensitivity of these methods, regression analyses for each method versus E. coli colony forming units (CFU) were performed. The storage stabilities of the bioprobe and biosensor were also investigated. The physico-chemical properties of in situ GUD were different from those of its commercially available counterpart. The temperature optimum for the former was between 35 and 40 °C while for the latter it was 45 °C. Commercial (reference) GUD had a pH optimum of 8.0 while the environmental counterpart exhibited a broad pH optimum of between pH 5.0 and 8.0. The liquid bioprobe had a limit of detection (LOD) of GUD activity equivalent to 2 CFU/100 ml and a detection time of 24 h. The method was less labour intensive and costly than the culturing method. The liquid bioprobe was stable for at least four weeks at room temperature (20 ± 2 °C). The biosensor was prepared by modifying a glassy carbon electrode with PNP degrading Moraxella 1A cells. The biosensor was 100 times more sensitive and rapid (5-20 min) than the spectrophotometric method (24 h), and was also able to detect GUD activity of viable but non-culturable cells. Thus it was more sensitive than the culturing method. Furthermore, the biosensor was selective and costeffective. The possibility of using a Pseudomonas putida JS444 biosensor was also investigated, but it was not as sensitive and selective as the Moraxella 1A biosensor. The Moraxella biosensor, therefore, offered the best option for on-line and real-time microbial water quality monitoring in South African river waters and drinking water supplies.

Whole Effluent Toxicity (WET) testing has been identified as one of the tools in the management of complex effluents in aquatic ecosystems. In South Africa, toxicity testing has not been required for regulatory purposes. Recently, the Department of Water Affairs and Forestry has adopted WET testing as a tool to evaluate the suitability of hazardous effluent for discharge into receiving environments. This has necessitated suitable procedures to be established for use in the South African situation. With the implementation of the new National Water Act (No 36 of 1998), industries have to comply with set standards to protect the aquatic environment. However, the South African Water Quality Guidelines for Aquatic Ecosystems have been set using international toxicity data, and it is not known if they are comparable with South African conditions. The aim of this study was to investigate the tolerances of selected indigenous riverine invertebrates to complex saline effluents. The study investigated the effects of kraft mill effluent to Tricorythus tinctus, a tricorythid mayfly from the Sabie River, Mpumalanga, and the effects of a textile effluent to baetid mayflies of the Buffalo River, Eastern Cape. Indigenous riverine invertebrates were chosen as test organisms, as there is no toxicity data in South Africa which could be used to evaluate the level of protection afforded by the South African Water Quality Guidelines for Aquatic Ecosystems. The use of indigenous riverine invertebrates added the challenge of variability of a wild population, and the use of a complex effluent as toxicant added the variability of effluent composition. In this study, WET testing was used to determine the dilution of whole effluents required for discharge. Hazard-based guidelines were developed for the disposal of kraft and textile effluents. The level of environmental hazard posed by different effluent concentrations was ranked, and was related to the River Health Class. This indicated effluent concentrations that may be allowed to enter the aquatic environment, e.g. 3% effluent concentration guideline for both general kraft effluent and general textile effluent for the protection of a Class A river. This approach could contribute to the use of an Environmental Risk Assessment, approach for the management of complex effluents. A number of acute 96 hour toxicity tests were conducted following an unreplicated regression design, using kraft and textile effluents as toxicants, mayfly nymphs as test organisms, and river water as diluent and control. Test organisms were sampled from unimpacted, flowing-water riffle areas, and were exposed in recirculating artificial streams (or channels) to a range of effluent concentrations. Mortality was selected as end-point and observed twice daily. The experimental results showed the variability and acute toxicity of both kraft and textile mill effluents. Baetids were more sensitive (mean LC50=16% effluent concentration) to General Textile Effluent (GTE), but less sensitive to Post Irrigation Textile Effluent (PITE). Textile effluent (PITE) held in a holding dam were therefore less variable and less toxic; suggesting that stabilization of the effluent could have contributed to reduced toxicity. Effluent composition, e.g. higher calcium levels, may also have contributed to lowering toxicity. T. tinctus was sensitive to kraft effluents, but showed less variable responses to Irrigation Kraft Effluent than General Kraft Effluent. Toxicity test data indicated that GKE, IKE and GTE should not enter the aquatic environment without treatment, as they can cause adverse effects to aquatic biota. Both kraft and textile effluents must therefore be treated before discharge. Different responses to different effluent batches were probably due to effluent variability. The use of indigenous organisms, and not a standard laboratory organism, could also have contributed to variability. A hazard-based approach could be useful, as it will provide a consistent basis for deciding on the acceptability of impacts, while allowing natural site-specific differences to be taken into account.

Industries producing highly polluted waste waters are having to purify their effluents to meet with ever increasing requirements laid down by water authorities. The South African Water Act of 1956 has prescribed a very high standard to which waste waters must conform before discharge into a South African water course. Enforcement of these standards falls under the jurisdiction of government authorities such as the Department of Water Affairs. Similarly, municipalities and other local authorities set standards with which trade effluents must comply before discharge into public sewers for treatment in a municipal sewage works. These local authorities are empowered to recover from the trader the additional costs incurred in treating trade effluents. Costs are usually levied in respect of volume, oxygen demand, settleable solids and the production of secondary sludge. In recent years, these standards have been enforced to an extent where the survival of several industries has become dependant on whether these industries are able to purify or dispose of their effluents in a manner acceptable to the water authorities. Chap. 1, p. 1.

M.Sc. (Environmental Management) / The main purpose of this study is to determine whether trends in rainfall patterns correlate to trends in water quality constituents for the Roodeplaat Dam Drainage Basin, thereby increasing the ‘dilution capacity’ potential of the aforementioned water system. The Roodeplaat Dam (reservoir) is a hypertrophic impoundment located approximately 20 kilometres north-east of Pretoria. The dam was originally designed for irrigational purposes and later became an important recreational site. In recent years it serves as an important source for Magalies Water, which represents a state-owned water board that currently supplies potable water to a large area north of Pretoria. The Roodeplaat Dam catchment consists of three contributing rivers to the inflow of the impoundment, namely: The Pienaars River (located in the centre of the catchment), the Edendale Spruit (east of the catchment) and the Moreleta/Hartebees Spruit (west of the catchment). There are also two Water Care Works (Zeekoegat and Baviaanspoort) within the catchment, which supplement additional inputs of treated effluent discharges to the reservoir. Temporal changes in selected physical, chemical and microbial constituents were analysed at established sampling points along each river, including a sample site located at the dam wall outlet. Such changes in water quality, in conjunction with rainfall patterns exhibited in the study area were analysed to determine whether an association exists between the two variables, and more specifically how rainfall impacts on water quality within the catchment which has a direct effect on the quality of the Roodeplaat Dam. Data for rainfall and water quality were analysed over a 10 year period, from January 1999 to December 2009. Water quality sampling results were obtained from the Department of Water Affairs. Rainfall data for the same time period in question was obtained from the South African Weather Service. Results for both variables were projected graphically and collated to determine whether rainfall trends have an impact on concentrations of water quality constituents. Constituent concentrations were also compared at each sample site. To quantitatively justify graphical results, the author preformed Pearson’s and Spearman’s correlation analysis to establish whether rainfall and water quality concentrations displayed significant associations. Results from graphical presentations and quantitative analyses identified that a correlation does exist between rainfall and water quality constituents, whereby an increase in rainfall tends to result in a decrease of water quality constituent concentrations. Microbial constituents contrasted to physical and chemical results, and displayed a strong positive correlation to rainfall. Rainfall therefore increases the ‘dilution capacity’ potential of the catchment, whereby the water system increases in its ability to receive and remove pollutants disposed in them by human induced land-use activities. It was also found from the study that the strength and association between rainfall and water quality constituents is affected by external, anthropogenic variables which also exert an influence on the quality of water present in the Roodeplaat Catchment Area. This includes additional inputs from the Baviaanspoort, which is located along the Pienaars River. Results from the sample site located on this river displayed no relationship for many of the water quality constituents tested. It has also been highlighted from the study how the landscape has been severely altered by the rapid rate of human induced land use activities in the past decade. Further investigations need to incorporate the influences of natural phenomena, such as rainfall, together with influences exerted from anthropogenic activities. This will provide clearer information on the interdependent factors at play which compromise the dilution capacity potential of the Roodeplaat Catchment Area and subsequently the poor water quality status exhibited at the impoundment. Once such externalities are accounted for, it is recommended that a suitable management plan be conducted for the Roodeplaat Catchment Area that is based on scientific grounding and proactively mitigates the impacts exuded by land-use activities, thereby improving the status of the Roodeplaat impoundment.

M.Sc. / The water quality monitoring project undertaken on the Blyde River in Pilgrim's Rest and surrounding area, provided information on various parameters. These included the macro variables (pH, temperature, conductivity, dissolved oxygen concentration, oxygen saturation percentage and turbidity), micro variables (ionic and metal concentrations) and fauna (fish and invertebrates). Field and experimental data were integrated to form a realistic and representative picture of the general state of health of the Blyde River. The macro variables (pH, temperature, conductivity, dissolved oxygen concentration, oxygen saturation percentage and turbidity) were all within the guideline limits as provided by the Department of Water Affairs and Forestry. The ionic concentrations (calcium, magnesium, sodium, chloride and nitrate) were acceptable and conformed to guideline values. The aquatic macro-invertebrate and habitat quality survey indicated that most of the sampling sites could be described as good. Sampling site 2 (next to reduction works) was classified as poor. This is the result of mining activity at this specific site situated at the rock dump at Peach Tree Creek. The extensive disturbance of the habitat is the result of 130 years of mining activities. The metal concentrations in the Blyde River exceeded the guideline limits, except for manganese. Aluminium toxicity is pH dependent, and increases with a decrease in the pH. The alkaline pH in the Blyde River acts as a buffer against the aluminium toxicity. The lead concentration in the Blyde River exceeded the Department of Water Affairs and Forestry guideline limit. Lead is hazardous to most forms of life. Zinc is toxic to fish and aquatic organisms at relatively low concentrations. Although nickel is a natural element of the earth and water, mining activities cause nickel emissions and an increase in the nickel concentrations in water systems. Copper is regarded as a highly toxic metal if present in high concentrations. Iron is not easily absorbed by aquatic organisms and because of its limited toxicity and bioavailability, described as a noncritical element. Chromium is biologically inert. Despite of a lack of information on the concentrations of metals in the Blyde River before the onset of mining activities at Pilgrim's Rest, it is clear that the extensive disturbance of the habitat at Peach Tree Creek and Vaalhoek, and to a lesser extent at Delvers' Creek exists. Present and past mining activities in the Pilgrim's Rest area resulted in the deterioration of the water quality in the Blyde River. Rehabilitation of the area around the rock dump at Peach Tree Creek will have to be done to prevent seepage from the rock dump and disturbed area to the river. Measures, such as the construction of paddocks and berm walls to collect seepage before it reaches the river, will have to be implemented. The water will then have to be treated before releasing it into the river. The acute, sub-lethal toxicity tests with nickel and lead were conducted based on the concentrations as derived from water samples taken from the Blyde River, during the monitoring phase of the project. The results of the blood physiological experimentation indicated that normal physiological functioning were disturbed when fish were exposed to sub-lethal concentrations of lead and nickel. Results indicated that stimulation of the immune system, osmotic stress and hypoxic conditions arise after lead and nickel exposure. Hypoxia arises because of a deficiency in the amount of oxygen reaching bodily tissues. Osmotic stress is a result of affected gill and kidney functioning. The metabolic variables indicated that the metabolism of trout was affected, because of stress associated with metal exposure. The nervous system functioning was also, affected, as derived from the enzymatic variables. Taking these factors into consideration, the normal functioning and survival of rainbow trout (Oncorhynchus mykiss) is hindered. The acute, lethal toxicity tests of nickel on rainbow trout (Oncorhynchus mykiss) and chubby head barb (Barbus anoplus) were performed using nickel concentrations as determined in the Blyde River. The 100% mortalities recorded, when exposing the fish to these concentrations, indicated that the Blyde River provides a buffer action against the toxic effect of nickel on the aquatic organisms. Should this buffer action be disturbed, for instance a sudden drop in water pH, the toxicity of nickel will increase and have detrimental effects on the aquatic organisms. Further deterioration of the water quality in the Blyde River should be avoided at all cost. Large scale yellow fish (Barbus marequensis) were only found at sites below sampling site no 8, which is alarming and a further confirmation of habitat degradation. To prevent further degradation of the water quality in the Blyde River annual biomonitoring in conjunction with experimental studies are suggested to obtain information, which enables effective managerial decision making. Measurements should be taken to reduce the impacts of mining and agricultural activities, if future studies indicate further water quality degradation. Objectives regarding the health of the aquatic environment should be set and actions taken to prevent the impactors from doing further harm. The Pilgrim's Rest area can be developed for Eco-tourism, and therefore the aim should be to create awareness of the river and its surroundings and involve people in the conservation thereof.

Magister Scientiae - MSc / The objective of this study was to investigate the feasibility of the application of low cost high capacity inorganic ion exchange material, synthesized form collected fly ash and acid mine drainage solid residues, for the decontamination of secondary co-disposal process waters, with emphasis on investigating the processes governing the solid/solution interface. / South Africa

The anaerobic digestion of tannery wastewaters was investigated with a view to using this form of treatment in the tanning industry. As these wastewaters are extremely complex and contain high concentrations of both inorganic and organic compounds, the effect of these individual compounds on the anaerobic digestion process was investigated in detail, in order to ascertain the fate of these compounds during the digestion process. The experiments comprising the initial toxicity study were carried out as adaptation experiments using a synthetic wastewater. It was found that the heavy metals such as chrome, aluminium and iron precipitated and accumulated in the sludge bed of the digesters . The soluble ions such as sodium and chloride were not retained and passed through the digesters. Approximately 20 % of the calcium ions were removed through precipitation, with the remainder being present in the digester effluent . Under the anaerobic conditions, ammonification of the organic nitrogen occurred, and influent sulphates were reduced to sulphides . These sulphides were present as either H2S, HS or insoluble sulphides. As these compounds under investigation on caused no inhibition of the anaerobic digestion process at the concentrations found in tannery wastewaters, the anaerobic treatment of these wastewaters appeared to be possible, provided the bacteria were given sufficient time to adapt to the potentially toxic compounds. However, despite the findings of the synthetic study, the successful anaerobic digestion of the tannery effluents could not be achieved. Although the use of acid was found to be essential in order to control the digester pH in the optimum range, the metabolism of the methanogenic bacteria was inhibited by the presence or absence of unknown compounds. Neither the addition of essential trace nutrients, nor the prevention of the competition between the methanogens and the sulphate-reducing bacteria were able to reverse this inhibition. As tannery effluents contain very low concentrations of phosphorous, it is possible that the methanogens were inhibited by a lack of phosphorous, which is essential during methanogenesis. In contrast to the results obtained from the effluent experiments, the anaerobic digestion of tannery sludge was found to be possible. Of the organic solids present in the sludge, 60 % were degraded and converted into biogas, which had a methane content greater than 70 %. The degradation of the organic solids ensured that COD and PV reductions of greater than 90 % were achieved, and the fate of the compounds in the digesters were in agreement with the findings of the v synthetic study. Efforts to improve the efficiency of the digestion process through the addition of trace nutrients and the use of a two-stage process were only successful in bringing about a minor improvement in digester performance. The overall results of this investigation show, therefore, that although the anaerobic treatment of the tannery effluent was not achieved, the successful anaerobic digestion of tannery sludge is possible at low loading rates. As many difficulties still need to be solved, a great deal of further research is necessary if anaerobic digestion is to be used on an industrial scale for the treatment and disposal of tannery wastewaters.

Internationally, water resources are facing increasing pressure due to over-exploitation and pollution. Integrated Water Resource Management (IWRM) has been accepted internationally as a paradigm for integrative and sustainable management of water resources. However, in practice, the implementation and success of IWRM policies has been hampered by the lack of availability of integrative decision support tools, especially within the context of limited resources and observed data. This is true for the Crocodile River Catchment (CRC), located within the Mpumalanga Province of South Africa. The catchment has been experiencing a decline in water quality as a result of the point source input of a cocktail of pollutants, which are discharged from industrial and municipal wastewater treatment plants, as well as diffuse source runoff and return flows from the extensive areas of irrigated agriculture and mining sites. The decline in water quality has profound implications for a range of stakeholders across the catchment including increased treatment costs and reduced crop yields. The combination of deteriorating water quality and the lack of understanding of the relationships between water quantity and quality for determining compliance/non-compliance in the CRC have resulted in collaboration between stakeholders, willing to work in a participatory and transparent manner to create an Integrated Water Quality Management Plan (IWQMP). This project aimed to model water quality, (combined water quality and quantity), to facilitate the IWQMP aiding in the understanding of the relationship between water quantity and quality in the CRC. A relatively simple water quality model (WQSAM) was used that receives inputs from established water quantity systems models, and was designed to be a water quality decision support tool for South African catchments. The model was applied to the CRC, achieving acceptable simulations of total dissolved solids (used as a surrogate for salinity) and nutrients (including orthophosphates, nitrates +nitrites and ammonium) for historical conditions. Validation results revealed that there is little consistency within the catchment, attributed to the non-stationary nature of water quality at many of the sites in the CRC. The analyses of the results using a number of representations including, seasonal load distributions, load duration curves and load flow plots, confirmed that the WQSAM model was able to capture the variability of relationships between water quantity and quality, provided that simulated hydrology was sufficiently accurate. The outputs produced by WQSAM was seen as useful for the CRC, with the Inkomati-Usuthu Catchment Management Agency (IUCMA) planning to operationalise the model in 2015. The ability of WQSAM to simulate water quality in data scarce catchments, with constituents that are appropriate for the needs of water resource management within South Africa, is highly beneficial.

Removal of nitrogenous compounds from precious metal refinery (PMR) wastewater is important in terms of avoiding eutrophication (environmental protection), metal recovery (increased overall process efficiency and value recovery) and reuse of treated water (maximum use of natural resources). Extreme pH conditions (4 to 13 depending on the wastewater stream), high chemical oxygen demand (> 10,000 mg/I), numerous metals and high concentrations of those metals (> 20 mg/l of platinum group metals) in the wastewater are the main challenges for biological removal of nitrogenous compounds from PMR wastewater. Nitrogenous compounds such as NH₄⁺-N and N0₃-N are strong metal ligands, which make it difficult to recover metals from the wastewater. Therefore, a bioprocess was developed for removal of nitrogenous compounds from carefully simulated PMR wastewater. A preliminary investigation of metal wastewater was carried out to determine its composition and physico-chemical properties, the ability to nitrify and denitrify under different pH conditions and denitrification with different carbon Source compounds and amounts. Even at pH 4, nitrification could be carried out. A suitable hydraulic retention time was found to be 72 hours. There was no significant difference between sodium acetate and sodium lactate as carbon sources for denitrification. Based on these results, a reactor comparison study was carried out using simulated PMR wastewater in three types of reactors: continuously stirred tank reactor (CSTR), packed-bed reactor (PBR) and airlift suspension reactor (ALSR). These reactors were fed with 30 mg/l of Rh bound in an NH₄⁺ based compound (Claus salt: pentaaminechlororhodium (III) dichloride). Total nitrogen removal efficiencies of > 68 % , > 79 % and > 45 % were obtained in the CSTR, PBR and ALSR, respectively. Serially connected CSTR-PBR and PBR-CSTR reactor configurations were then studied to determine the best configuration for maximum removal of nitrogenous compounds from the wastewater. The PBR-CSTR configuration gave consistent biomass retention and automatic pH control in the CSTR. Ammonium removal efficiencies > 95 % were achieved in both reactors. As poor nitrate removal was observed a toxicity study was carried out using respirometry and the half saturation inhibition coefficients for Pt, Pd, Rh and Ru were found to be 15.81, 25.00, 33.34 and 39.25 mg/l, respectively. A mathematical model was developed to describe the nitrogen removal in PMR wastewater using activated sludge model number 1 (ASMl), two step nitrification and metal toxicity. An operational protocol was developed based on the literature review, experimental work and simulation results. The optimum reactor configuration under the set conditions (20 mg/I of Rh and < 100 mg/I of NH₄⁺-N) was found to be PBR-CSTR-PBR process, which achieved overall NH₄⁺-N and N0₃⁻-N removal efficiencies of > 90 % and 95 %, respectively. Finally, a rudimentary microbial characterisation was carried out on subsamples from the CSTR and PBRsecondary. It was found that the CSTR biomass consisted of both rods and cocci while PBRsecondary consisted of rods only. Based on these experimental works, further research needs and recommendations were made for optimisation of the developed bioprocess for removal of nitrogenous compounds from PMR wastewater.

M.Sc. / The world is focusing on increasing the number of people who have access to safe drinking water due to the ascending numbers of drinking water related illnesses reported annually in rural areas where water is not treated before consumption. To meet this goal, household water treatment has to be introduced especially in places where homes are wide apart making centralised water treatment improbable. Most readily available household water treatment systems (HWTS) such as membrane filters may not be affordable in rural areas due to power requirements and degree of ability to use and maintain them. This study was therefore aimed at designing and constructing HWTS using readily available material such as sand, gravel, zeolites and clays. Five HWTS were designed, built, evaluated and compared based on their ability to remove chemical contaminants such as iron, arsenic and fluorides from drinking water. The types of filters that were used during this study are the biosand filter (BSF), a modified biosand filter with zeolites (BSFZ), a silver impregnated porous pot (SIPP) filter, a ceramic candle filter (CCF) and a bucket filter (BF). Effectiveness of the filters in reducing physical parameters such as turbidity and visual colour was also assessed. The water treatment devices had the following flow rates; 1.74 L/h – 19.20 L/h (BSFZ), 0.81 L/h – 6.84 L/h (BSF), 0.05 L/h – 2.49 L/h (SIPP) and 1.00 L/h – 4.00 L/h (CCF). The flow rates were high at the early stages of filter use and decreased with increase in the volume of water filtered through. The flow rates of the filters were affected by the turbidity of intake water which was between 1.74 NTU – 42.93 NTU and correlated to chlorophyll a concentrations. The household water treatment technologies reduced turbidity to levels less than 1 NTU (> 90% reduction) in the following order SIPP > BSFZ > BSF > CCF > BF. The filters achieved greater than 60% retention of calcium, magnesium, iron and arsenic. These contaminants with the exception of arsenic were reduced to acceptable levels of the South African National Standard of drinking water (SANS 241, 2004). Compared to the other filters, the BSFZ performed better in removing nitrates, phosphates and fluorides although the overall retention efficiency was low. Total organic carbon was removed greatly by the CCF (39%) and the least removal was by the BF. The overall performance of the filters in reducing contaminants from drinking water was in the order BSFZ > BSF > SIPP > CCF > BF. Filter washing vi resulted in an overall increase in the flow rates of the filters but negatively affected turbidity reduction. The filters still removed contaminants after total cumulative volumes of 1200 L (BSFZ, BSF, CCF and BF) and 300 L (SIPP) were filtered through the devices. The five evaluated filters have several advantages to the readily available technologies and the advantages include ease of construction, operation and maintenance. The filters are gravity driven and work independent of temperature. These HWTS incorporate safe storages fitted with spigots to eliminate recontamination of water when it is drawn for use. The filters can produce enough drinking and cooking water for a family of six members due to their high flow rates. The BSFZ, BSF, SIPP, CCF and BF may therefore be considered for treating contaminated water at household scale in places where water is taken directly from the source without treatment.