Anthropogenically-derived substances, including pharmaceuticals and personal care products, endocrine-disrupting chemicals, and pesticides, are increasingly being detected in drinking water supplies and wastewater effluents. Concerns over the presence of these compounds in water supplies include their ability to impart toxicological activity, their capacity to spread antibiotic resistance, and their potential to affect cell-signaling processes. For these reasons, water treatment processes geared towards removal of these trace organic contaminants are vital. In this work, ozone was used to treat four pharmaceutical contaminants: ciprofloxacin, cyclophosphamide, erythromycin, and ifosfamide. Ciprofloxacin and erythromycin are antibiotic/antimicrobial compounds, and cyclophosphamide and ifosfamide are chemotherapy agents. Ozone effectively transformed all four pharmaceuticals, even in the presence of background natural organic matter, which exerts a considerable ozone demand. The apparent rate constants for the reaction of the pharmaceuticals with ozone at pH 7 were determined: 3.03 M-1s-1 for cyclophosphamide; 7.38 M-1s-1 for ifosfamide; 1.57×104 M-1s-1 for ciprofloxacin; and 7.18×104 M-1s-1 for erythromycin. Cyclophosphamide and ifosfamide, which do not react quickly with ozone, exhibited high rate constants (2.7×109 M-1s-1) for transformation by hydroxyl radicals, which are formed through ozone decomposition. Nevertheless, complete removal of cyclophosphamide and ifosfamide was achievable using a novel continuous aqueous ozone addition reactor and an ozone-based advanced oxidation process (peroxone). In ozone-based processes, pharmaceuticals are systematically transformed via complex oxidative pathways towards CO2, H2O, and the oxidized forms of other elements. Intermediate oxidation products containing oxygen atoms or hydroxyl groups substituted into the chemical structure of the parent pharmaceutical were identified using liquid chromatography-mass spectrometry (LC-MS). Given the structural similarity of intermediate oxidation products to the parent pharmaceuticals, an antimicrobial activity assay was employed to monitor the removal of pharmacological activity associated with ciprofloxacin, erythromycin, and their respective intermediate oxidation products throughout treatment. For solutions containing ciprofloxacin or erythromycin, ozone was able to completely eliminate the corresponding antimicrobial activity. Ciprofloxacin intermediate oxidation products were pharmacologically active; however, erythromycin’s intermediate products did not contribute to the residual antimicrobial activity. These results suggest that the design of conventional and advanced ozone-based processes must incorporate ozone demand from background organic matter and account for destruction of pharmacologically active intermediates. / text

This is a project about The Water Treatment System at Djupdalen. The leakage water comes to the Water Treatment System from a deposition plant through the land. The leakage water is characterized by a high concentration of nitrogen and the system is based on biological removing of the nitrogen in the water, by nitrifying and denitrifying bacteria. Four different problems are found in the system: 1. High level of nitrogen concentration in the outgoing water of the system. It should be due to the lack of phosphate in the water, that do not let the bacteria to grow. 2. Low temperature during the most part of the year. Nitrifying and denitrifying bacteria are temperature-dependent, that are very slow at low temperatures. 3. High oxygen concentration in one of the anoxic pond, where the denitrification process take place. This oxygen concentration is too high for denitrifying bacteria to work. 4. The nitrification and denitrification bacteria need to be “old” to work efficiently. They need a surface to attach, because if not they flow with the water and they leave the system. And four possible solutions for the system are presented: 1. Phosphate should be added to the system to let bacteria growth. 2. Store the water at a store pond during the winter months and transport it to the system when the temperature is optimum for the bacteria to work. 3. Add carbon matter to improve the carbon oxidation and to low down the oxygen levels at the anoxic ponds. 4. Two options are presented to improve the system, the first one is based on the construction of a dark wavy bottom in the channel system, which will give a surface for bacteria to attaché, it will produce oxygenation in the water, and it will also improve the water temperature; and the second one is based on the addition of panels made of black material, which will give to bacteria a surface to attach, and improve the water temperature.

The presence of naturally occurring arsenic in groundwater has caused a number of social and health-related problems for the rural poor of Bangladesh. Today, it is estimated that 42 – 60 million people in Bangladesh consume water at arsenic concentrations greater than the World Health Organization (WHO) standard of 10 μg/L. The arsenic-iron removal plant (AIRP) has been widely used to remove arsenic from drinking water across much of the country; however, AIRPs show variable levels of efficiency and have often failed to meet the WHO standard. Those who continue to drink water with elevated concentrations of arsenic are prone to skin disease and various cancers. The thesis presented here examines methods to mitigate exposure of the rural poor to arsenic by modifying the AIRP and increasing our understanding of the chemical and social factors associated with its use. This objective is accomplished via four channels: (1) assessment of the chemical processes occurring within the AIRP, (2) evaluation of three retrofits, (3) development of a waste management strategy, and (4) examination of social factors affecting use and sustainability of the AIRP. Household AIRPs installed in the village of Mohadevpur, in the Manikganj district, are examined.

An evaluation of BioSand Filters, a method of Household Water Treatment, was conducted in Posoltega, Nicaragua, with objectives of determining the long-term filtration efficiency and the rate of sustained use. Field methods included microbial and turbidity water quality testing and interviews with filter users regarding the operation, maintenance and perceptions towards the filters. Of the 234 BioSand Filters installed in 1999 and 2004, only 24 were found to still be in operation. The average filtration efficiency was found to be 98% for total coliforms, 96% for E. coli and 88% for turbidity. Statistically significant effects on filtration efficiency were detected for the source contamination, the inverse of the flow rate, and the standing depth of water over the sand. A follow-up laboratory QA/QC procedure was undertaken to validate the field methods, which consisted of membrane filtration (MF) with m coliBlue24 growth media, and SolarCult dipslides. It was found that MF with m coliBlue24 produced useful reproducible results, and is an appropriate method for conducting field water quality testing. The dipslides were found to be an appropriate tool for testing source water quality and assessing the applicability of BioSand Filters, and may be an appropriate tool for local health representatives to promote safe water practices within the community. However, the dipslides should not be used as a presence / absence test for drinking water due to the high limit of detection. The low rate of sustained use (10%) is mostly a result of the structural failure of the concrete walls of the filter, in particular for those filters from 2004. Anecdotal evidence suggests insufficient quality control during the construction. The filtered water and the stored post-filtered water did not meet the WHO guidelines for safe drinking water on account of the presence of E. coli. Also identified were improper maintenance practices and unsafe storage of post-filtered water. These problems could have been addressed through the development of a holistic water system approach, such as the World Health Organization Water Safety Plan.

Contaminated drinking water is one of the major health challenges facing people in the developing world. The country of India leads the world in under age five mortality due to diarrheal disease, which is attributed to water and food contamination. While the Indian government has made progress in expanding access to improved water sources in the last decade, the microbiological quality of the water is unpredictable. Point of use household water treatment systems can provide clean drinking water for people who do not have access to a clean water source. This report examines five non-electrical point of use household water treatment options which have been extensively field-tested and could potentially be used in rural, South Indian villages: chlorine disinfectant, chlorine-flocculant sachets, ceramic filters, biosand filters and solar disinfection. A case study of a village in Andhra Pradesh is presented that highlights the factors to consider when introducing a new POU technology into a community.

The environmental and agricultural viability of land disposal of a water treatment residue (WTR) from the Midmar Water Treatment Works of Umgeni Water was investigated by determining answers to four broad questions: 1. What effects would the application of the WTR have on plants growing on the treated soils? 2. What effects would application of the WTR have on soil chemical properties? 3. What effects would the WTR have on the soil solution composition (and by implication the quality of the groundwater)? 4. Could this material be used to reduce solubility of potential pollutants? To answer these questions, the following experiments were set up, and their respective results are reported. 1. Effects of the water treatment residue on plant growth This was investigated in a pot experiment and two field experiments. In the pot experiment five soils, two Huttons (Hu-M and Hu-T), an Inanda (la-C), a Namib (Nb-F) and a Shortlands (Sd) were used to grow perennial ryegrass ((Lolium perellne). All samples were fertilized with a basal dressing of N, P, K, Mg and S. Two lime levels were added to the Ia-C and Nb-F soils, the higher calculated to reduce acid saturation to 1%, and the lower being half of that. The WTR was applied at rates of 0, 40, 80 and 120 Mg ha-1. All treatments were in triplicate. Eight cuts in all were made of the perennial ryegrass. The dry matter (DM) yield of perennial ryegrass grown in the pot experiment increased with the WTR applied in all five soils although the highest increase was with the acidic Ia-C and Nb-F soils. The fact that the highest yields were on the strongly acid soils suggests that the liming effect of the WTR could have contributed, more so considering that lime also increased yields in these soils. It was, however, clear that no one factor was responsible for the increase in yield as the timing effect could not explain the results of the other three soils. At the two field experiments perennial ryegrass was grown at Brookdale Farm from 1998 to 2001, after which the site was re-seeded with tall fescue (Festuca arundinaceae). At Ukulinga Farm tall fescue was grown from the outset in 2000. In the two field experiments with both perennial ryegrass and tall fescue, no significant increase in yield was apparent. Importantly, however, from an environmental point of view there was no decrease in yield whether the WTR was incorporated or applied as a mulch. This was observed even at the highest rates of application, namely 1280 Mg ha-1. The growth on the mulched plots was often observed to be better than any of the other treatments, including the control. Analysis of the plant material from both pot and field experiments indicated that the WTR neither pollution of the groundwater by nitrates. However, analysis of saturated pastes from soils at both field experiments showed that the levels of nitrate were increased by application of the WTR in only the fallow plots. 4. The water treatment residue as a possible pollutant-reducing agent The effect of the water treatment residue on the sorption of P and heavy metals (Cd, Ni and Zn) was studied in the laboratory. Soils treated with WTR were equilibrated for 6 hours in 0.005 M calcium cWoride solution containing a known concentration of each element. For the coarse-textured soils, initial P concentrations ranged from 0 to 1000 mg kg-1 as opposed to 0 to 1800 mg kg-1 for the clay soils. Treatments of WTR used were 0, 80, 320 and 1280 Mg ha-1, both incubated and non-incubated. At high initial P solution concentrations, the WTR increased the extent of sorption in the coarser textured soils (Hu-T, Nb-A, Nb-F, Va and We), and decreased it in highly sorbing Av, Hu-M, la-C and la-W soils. In general though, the WTR greatly reduced soluble P. For Cd, Ni and Zn only one concentration, 50 mg kg-1, was studied using the incubated soil samples as affected by WTR rates from 0 to 1280 Mg ha-1. For all three metals, the amount sorbed increased with increase in amount of WTR for the nine soils studied, namely the Av, Hu-F, Hu-M, Hu-T, la-C, la-W, Nb-F, Va and We. In many cases the sorption was so high that more than 40 mg kg-1 of the initial concentration was removed from solution. Even for those soils with high sorption capacity e.g. the Va and We, the WTR still increased sorption by up to an average of more than 25% for Cd and more than 40% for Ni and Zn. Because for the Av and la-W soils liming also increased sorption, it could be assumed that the accompanying increase in pH as a result of the addition of WTR promoted precipitation of metals, and/or the resultant increase in negative charge increased their adsorption. These results show that where excess concentrations of soluble heavy metals may occur (especially in coarse-textured soils), and where there is concern about run-off with high P concentrations then this WTR could be considered to immobilize these elements and render them less harmful to the environment. General comments and management guidelines. Based on the results reported above, it is apparent that the WTR can be safely disposed of onto land. It has been demonstrated in the current investigation that rates of application can be as high as 1280 Mg ha-1. Rates of application to land higher than 1280 Mp; ha-1 could probably be acceptable - this was the highest rate tested in this investigation - where the residue is produced in large amounts at the plant, and land for disposal is somewhat limited. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

No abstract available. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2006.

Dyes are often recalcitrant organic molecules that produce a colour change and contribute to the organic load and toxicity of textile industrial wastewater. Untreated effluent from such sources is harmful to aquatic life in the rivers and lakes due to reduced light penetration and the presence of highly toxic metal complex dyes. The use of alum as flocculant/coagulant in wastewater treatment is not encouraged as it induces Alzheimer’s disease in humans and results in the production of large amounts of sludge. Therefore, the development of safe and biodegradable flocculating agents that will minimize environmental and health risks may be considered as an important issue in wastewater treatment. Bioflocculants are extracellular polymers synthesized by living cells. In this study, bacterial bioflocculants were assessed for their ability to remove dyes from textile wastewater as well as reducing the microbial load in untreated river water. The bacteria were isolated from a wastewater treatment plant and identified using standard biochemical tests as well as the analysis of their 16S rDNA gene sequences. Six bacterial isolates were identified viz. Staphylococcus aureus, Pseudomonas plecoglossicida, Pseudomonas pseudoalcaligenes, Exiguobacterium acetylicum, Bacillus subtilis, and Klebsiella terrigena. The flocculating activities of the bioflocculants produced by these isolates were characterized. The effect of temperature, pH, cations and bioflocculant concentration on the removal of dyes, kaolin clay and microbial load was also determined. The amount of bioflocculants produced by the bacterial isolates ranged between 5 and 27.66 g/l. According to the findings of the present study, bacterial bioflocculants were composed of carbohydrates, proteins, uronic acid, and hexosamine in varying quantities. The bioflocculants were effective to varying degrees in removing the dyes in aqueous solution, in particular whale dye, medi-blue, fawn dye and mixed dyes, with a decolourization efficiency ranging between 20-99.9%. Decolourization efficiency was influenced by the bioflocculant concentration, pH, temperature, and cations. The bacterial bioflocculants were also capable of reducing both the kaolin clay and the microbial load from river water. The flocculating activity ranged between 2.395–3.709 OD-1 while up to 70.84% of kaolin clay and 99% of the microbial load from the river water was removed. The efficiency of kaolin clay flocculation increased with higher concentration of bacterial bioflocculants. The optimum pH for the flocculating activity was observed between 6 and 9. The best flocculating activity was observed at 28oC. Divalent cations such as Mg2+ and Mn2+ improved the flocculation while salts such as K2HPO4, CH2COONa, and Na2CO3 did not. The findings of this study strongly suggest that microbial bioflocculants could provide a promising alternative to replace or supplement the physical and chemical treatment processes of river water and textile industry effluent. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2008.

High voltage treatment technology has been developed in this thesis and had initially shown promise in its effectiveness in reducing microorganisms found in water supplies. Initial testing found that the high voltage could destroy over 99.9% of the bacteria S. marcescens (a 3-log reduction). Cited literature on the effects of high voltage pulsed electric fields (PEFs) on various microorganisms have shown that high destruction rates of up to 9-log can be achieved. Thus by increasing the electric field strength or exposure time, or by improving the design of the electrode flow chamber, better results should be achieved using high voltage on water. However, contrary to this, upon further design improvements the 99.9% destruction threshold was rarely increased. The initial slow flow device of one litre-per-minute (1 LPM) was scaled up to flows of 10 LPM and 33 LPM. However, these faster flow devices were even less effective in the destruction of bacteria, destroying only 99% of S. marcescens (2-log reduction). No physical or technical design parameters could account for this low performance. One possible reason for these low results was in the preparation of the bacteria themselves. It was discovered that the growth stage of bacteria prepared for experiments had a large effect on the results. Bacteria harvested in the early growth stage could be nearly all destroyed by the high voltage (greater then 4-log reduction), whereas those harvested in the late stationary stage were much more resistant (less than 0.5-log reduction). Bacteria naturally occurring in water supplies will mostly be in a non-metabolising state. This implies that they will be more resistant to high voltage exposure than bacteria grown in a laboratory under standard testing procedures. Thus standard testing procedures for this device do not give accurate results. Further research into the mechanism behind the bacterial resistance is required to improve the performance of high voltage devices. A combination of different technologies may also prove effective in overcoming the resistance mechanism. These improvements are required before high voltage treatment can be properly developed and commercially exploited.

Application of low pressure membranes in drinking water treatment, including both microfiltration (MF) and ultrafiltration (UF), have witnessed a rapid increase in the past decades. Low pressure membranes are considered a good technology in retrofitting existing conventional drinking water treatment plants or in newly constructed plants to meet the stringent regulations for drinking water treatment that aim at preventing health risks of waterborne diseases. Enteric viruses are one of the major types of waterborne pathogens, and they can be commonly found and are persistent in the environment. Both the United States and Canada require a 99.99% (4-log) removal of viruses during the drinking water treatment train. Unlike MF membranes, UF membranes have a very good potential for removing enteric viruses from the water due to their smaller pores comparable to the size of viruses. Drinking water regulations/guidelines in both the United States and Canada do not grant UF membranes any removal credit for viruses by default; however they have the provision that, in certain cases, virus removal credit may be granted based on pilot scale challenge testing. A better understanding of the interaction between the UF membranes and virus rejection can help to establish a removal credit for UF membranes. An essential part of this will be the effect of the membrane operation on the rejection of viruses to determine if UF membranes can offer a consistent removal of viruses. Membrane fouling is one of the major problems in membrane operation and it can affect the rejection characteristics of the membrane and improve its performance. The aim of this study was to investigate the removal of virus surrogates (MS2 and φX174 bacteriophage) using a commercial UF membrane under different conditions, to obtain information about the removal mechanisms of viruses. The experimental filtration unit was designed to have similar conditions like the full scale membrane treatment plants. The UF membrane used in this study provided very good removal of both MS2 and φX174 bacteriophage. The obtained results were consistent and in agreement with the expected removals based on the membrane characterization results and types of virus surrogate. As part of this work, a detailed study to improve methods for characterizing the pore size distribution of membranes was conducted. In the second part of the study, two different types of surface waters were used to study the effect of membrane fouling on virus removal. It was found that mainly hydraulically irreversible fouling could significantly improve the virus removal by UF membranes. Different cleaning regimes that are used in treatment plants had varying effects on virus removal. After maintenance cleaning, virus removal remained higher than that of clean membranes, and only chemical cleaning was effective for completely removing membrane foulants and returning virus removal back to base levels. Advanced analytical techniques were used to define the nature of the fouling layer on the membrane surface and how the foulants affected the rejection of viruses. Finally, our study showed that UF membranes are a robust treatment technology for removing different types of enteric virus surrogates from water under different operational conditions. Close monitoring of the UF unit performance and direct integrity testing can possibly detect membrane problems that can affect the rejection of viruses. Based on the virus physical characteristics and a detailed study of the membrane surface characteristics, especially the pore size distribution of the membrane, the removal of the specific virus can be closely estimated.