In the wake of the growing dependence on small water treatment plants (SWTPs) in providing quality water to rural areas and the global burden of water borne diseases, this study sought to examine the efficiency of 55 SWTPs located in rural or peri-urban areas of Limpopo and Mpumalanga Provinces in order to gauge the safety of water supply for human consumption. The microbiological and physical parameters of raw water, treated water and water in the distribution systems were examined using standard methods. Management issues impacting on quality of water supply were determined by use of questionnaires and focus group discussions. Results obtained showed that the pH, turbidity, temperature and conductivity of the raw water in SWTPs studied in both provinces ranged between 6.46 to 9.05 pH units, 0.19 to 8.0 NTU, 15.4oC to 31.40oC and 44.40.4 μS to 108 μS respectively. Water quality compliance at point of use (treated water) according to the Department of Water Affairs and Forestry of South Africa guidelines in SWTPs studied in both provinces were 85% for faecal coliforms and 69% for total coliforms. In the distribution systems, TCCs, FCCs and HPCs were within recommended limits except for few SWTPs suggesting a possibility of inadequate treatment and this may represent post-treatment contamination and possible risk of infection from these water supply sources. Physical parameters were generally within the recommended ranges . In terms of administrative issues, some plant operators did not have adequate knowledge of the functioning of the SWTPs and most were unable to calculate chlorine dosage, determine flow rates or undertake repairs of basic equipment. Poor working conditions , frequent stock depletion of chemicals , lack of maintenance culture , lack of emergency preparedness and poor communication were also cited . The study has revealed that the microbiological quality of raw water was very poor but that water treatment was efficient in the majority of SWTPs studied in both provinces. Regular monitoring of microbial and physico-chemical parameters of water quality served by the different SWTPs to the population is recommended to gauge their safety for human consumption. Issues such as enhanced incentives and periodic training of plant operators, improved communication and conditions of service , periodic stock inventory and entrenchment of maintenance culture may be necessary to ensure sustained and efficient water distribution systems.

No description available.

In a constructed treatment wetland applied to domestic wastewaters, long term studies and increased operational experience indicate that phosphorus removal is variable or inconsistent, especially in cold-climate applications. These inconsistencies can be attributed to the complexity of phosphorus removal mechanisms, and the lack of consideration of these complexities in the design, installation and operation of these treatment systems. Sorption of phosphorus to the wetland media is generally considered to be the major removal mechanism. The research described in this thesis was conducted to determine the most suitable material for application in a constructed wetland and a post wetland-filter to treat phosphorus in wastewater effluents, taking advantage of sorption processes. The present work was conducted at lab (bench) scale. Three potential sorptive media were studied in the research program, namely gravel, slag and clinker. Several methods for media analysis were investigated as potential screening tools for media selection. To determine the various forms of phosphorus in the media, sequential extraction tests were considered to be most relevant and useful for this research. Batch testing and flow cell testing along with sequential extraction tests were conducted to predict the sorption capacity and performance of the media for the long term (10+ years) removal of phosphorus. The protocols developed in this thesis permitted a rigorous assessment of the media and should be applied in any assessment of sorptive media to select the best medium. Gravel showed some sorption of phosphorus although it was not sufficient to meet the regulatory limits for the effluent concentration. Clinker and slag showed high sorption capacity as compared to gravel and the observed effluent concentration was below the regulatory limits. All three media showed the presence of background phosphorus, with clinker having the highest amount of background phosphorus. However, except gravel, clinker and slag did not show any significant amount of phosphorus being leached out during low phosphorus loading conditions. Taking all factors under consideration, slag and clinker were identified as good media for phosphorus removal. Media that have proven to have high sorption capacities and also retention capabilities should be considered for applications where phosphorus removal is the prime objective. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2007-12-10 11:40:49.657 / NSERC

Over the last few decades increasing attention has been paid to the effects of land use activities and land management on stream water quality. Recent research has largely focused on dominant land uses such as urban development and agricultural cropland. The relative effect of land use activities and management on stream chemistry in sub-tropical rangeland ecosystems, where much of the land use is converted to pasture and agriculture is largely unknown. This study examined stream water quality and land use in a sub-tropical watershed in Northeast Texas largely dominated by rangeland. The study site, White Oak Creek Watershed located in the Sulphur River Basin, has been identified as an impaired stream due to low dissolved oxygen concentrations and subsequently listed on the Texas Commission for Environmental Quality's 303d list (TCEQ). In an attempt to determine potential sources of the low dissolved oxygen concentrations, twenty different chemical constituents were analyzed at 18 different sample sites in the tributaries of White Oak Creek and also along the main stem from April 2010 to March 2011. Dissolved oxygen concentrations over the study period were consistently above the minimum standard required by TCEQ and showed no indication of impairment. Correlation analysis did not show any clear correlation between dissolved oxygen and any specific land use, or any chemical constituent. Some nutrients and suspended sediment concentrations were significantly different among the sub-catchments of White Oak Creek. Urban land uses were significantly and positively correlated to electrical conductivity, ammonium-N, magnesium, calcium, and dissolved organic carbon. Agricultural land use was significantly and positively correlated to orthophosphate-P, dissolved organic nitrogen, total suspended solids, and turbidity. Forests were inversely and significantly related to nitrate-N, orthophosphate-P, sulfate, dissolved organic carbon, total suspended solids, and turbidity. The study suggested that by maintaining a relatively high proportion of forested land in a watershed that water quality can be improved.

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No description available.

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The purpose of this research was to improve understanding of the quality of drinking water for domestic consumption in the City of Kumul, China. The guidelines for drinking water testing in the City of Kumul were assessed and compared with actual practices. Local households in the urban center were interviewed in order to assess public attitudes towards drinking water. The results showed that the quality of treated water did not pose a direct threat to human consumers, but there were opportunities for improvements in the areas of source water protection, water treatment processes, and communication between authorities and the public. 74% of urban households personally treated their tap water prior to consumption, most commonly by boiling, to improve drinking water quality. It is recommended that the local government should seek to improve communication between the water treatment authority and the public to ensure water quality in the City of Kumul.

An understanding of the reactivity of hydrophobic organic micropollutants (HOMs) is of paramount importance to water quality managers because of their toxicity, persistence, and liability to bioaccumulate. In this study, the role played by the main estuarine variables (organic matter, suspended particulate matter [SPM], particle type and salinity) on HOM behaviour was investigated by employing samples from estuaries with different geochemical signatures (Chupa, Russia, and the Dart, Plym, Beaulieu and Carnon, U K ) . A laboratory-based technique was developed for the determination of the solubility and sorptive behaviour of HOMs using 14C-labelled, beta-emitting organic compounds (2,2\5,5'-tetrachlorobiphenyl (2,2’5,5'-TCB), bis(2-ethylhexyl)phthalate ester (DEHP), and benzo[a]pyrene (BaP)) coupled with liquid scintillation counting. The results indicate that relative solubility is mainly dependent upon the type of dissolved organic carbon (DOC) present, not its concentration, and is reduced with increasing salinity. The uptake of 2,2’5,5'-TCB and BaP by particles is time dependent with a system response time (the time required to achieve 63% of the new equilibrium) of about 0.37 hours for 2,2',5,5’-TCB and 0.02 hours for BaP. The adsorption, expressed as particle-water partition coefficients, KDS, is to a varying extent dependent on DOC, salinity and particle characteristics (iron/manganese hydroxides, particulate carbon and specific surface area). Adsorption is best defined by a linear isotherm and is enhanced in sea water compared with river water owing to a reduction in charge on particle surfaces at high ionic strengths. This effect has been quantified using an adsorption salting constant, Gp, whose values are typically in the range 0.4-2 L mol-2 The inverse relationship between KD and SPM concentration, an effect well documented in the literature, has been defined by a simple power law (KD = a SPM-b where a and b are site and compound-specific constants). Typical values for a and b are approximately 4x10^ and 0.6 for 2,2',5,5'- TCB, 50x105 and 1.0 for DEHP, and 2x105 and 0.5 for BaP, respectively. Empirical parameterisation of these effects are extremely useful for encoding into numerical transport and distribution models, and their application is demonstrated in this thesis by calculating the retention of HOMs by estuaries.

The aim of this study was to analyse the interaction of natural organic matter (NOM) with the disinfectant ozone and the influence these interactions have on bromate formation and the production of assimilable organic carbon (AOC) in Australian drinking waters. / In order to achieve this, four local source waters (Hope Valley Reservoir, Myponga Reservoir and Warren Reservoir and Lake Wallace) were selected based on the variability of their raw water characteristics. Ozonation experiments on all four waters revealed that, even at low ozone / DOC ratios, bromate formed in levels above current regulatory guideline values. Previously developed bromate formation prediction models based on (overseas) raw water quality characteristics were assessed and found generally not to be applicable to the prediction of bromate in Australian drinking waters. / The NOM from two of these raw waters (Myponga and Lake Wallace) was first concentrated via reverse osmosis and then fractionated according to molecular weight (using ultrafiltration) and character (using ion exchange resins). This resulted in the production of eight distinct isolates derived from each source water. Analysis of the structural makeup of each fraction by techniques such as ¹³C-NMR, UV spectroscopy and HPSEC revealed significant differences in character and structure of each NOM isolate. / Ozonation of these fractions under identical conditions showed that the amount of bromate formed was dependent on the individual fraction and, more importantly, on the structural characteristics of that particular isolate. Kinetic studies revealed an apparent relationship between ozone decomposition and the formation of bromate. Analysis of these data using the previously developed "bromate yield" concept revealed the existence of a bromate formation threshold value for each NOM isolate, ozone being consumed readily upon addition to the sample before bromate begins to form. Once the ozone threshold has been met, bromate (per unit of consumed ozone) forms at a rate dependent on the characteristics of each fraction. Analysis using the "ozone exposure" concept confirmed this trend. / Research into the dominant mechanism of bromate formation revealed that the response of each fraction was dependent on whether the formation mechanism was dominated by direct oxidation (via the molecular ozone mechanism) or indirect oxidation (via the hydroxyl radical mechanism). / A study of 30 randomly selected bottled waters for disinfection by-products (DBPs) found that bromate was present in 12, with all being above guideline levels, some significantly so, posing a possible health concern. THMs were detected in 18 samples but in all cases were present at low concentrations. / An investigation into the influence each NOM isolate has on the formation of assimilable organic carbon (AOC) through the analysis of bacterial regrowth potential (BRP) values revealed that certain fractions may be contributing more to the BRP of the raw water and that the effects are dependent on the character of the NOM in the water. If the more biodegradable fractions can be preferentially removed after ozonation, problems caused by the formation of ozonation by-products will be reduced. / Thesis ([PhDAppliedScience])--University of South Australia, 2004.