The importance of water as a mechanism for the spread of disease is well recognized. This study conducted household surveys and measured several physical, chemical, and microbial water quality indicators in 37 elevated storage tanks constructed of different materials (polyethylene, fiberglass, cement) located in a peri-urban community near Cochabamba, Bolivia. Results show that although there is no significant difference in physical and chemical water quality between polyethylene, fiberglass and cement water storage tanks there is a difference in microbial contamination as measured by E. Coli counts (p = 0.082). Evidence points toward elevated water temperatures that increase along the distribution system (from 10.6°C leaving the treatment plant) to within the black polyethylene storage tank (temperatures as high as 33.7°C) as the most significant factor in promoting bacterial growth. Results indicate that cleaning frequency may also contribute to microbial water quality (p = 0.102).

Hydrogen sulfide imparts odors and taste to drinking water and can be corrosive to distribution systems. Groundwater sources used to produce drinking water tend to have sulfide concentrations ranging from below 0.1 to over 3 mg/L. Under anaerobic conditions, hydrogen sulfide can be formed from reduction of sulfate and elemental sulfur through chemical or biological reactions. Therefore, to decrease the potential for hydrogen sulfide in water systems, control of all forms of sulfur should be consistent. Hydrogen sulfide in groundwater can be controlled through conversion or removal mechanisms. Conversion reactions result from chemical or biological reactions that oxidize hydrogen sulfide to elemental sulfur or sulfate, depending on the reaction conditions. Removal reactions include stripping, anion exchange, or formation of a precipitate that can be removed through solid/liquid separation processes. In many groundwater treatment systems, hydrogen sulfide is controlled through aeration, chlorine oxidation, or a combination of these two methods. In addition to chlorine, other oxidizers can be used including hydrogen peroxide, UV, ozone, or potassium permanganate. The main factors that influence whether hydrogen sulfide is oxidized to elemental sulfur and/ or sulfate are pH, temperature, and the type and dose of oxidant. In recent years alternative treatments technologies such as anion exchange, have become available. It is interesting to note that this technology was proposed as early as the middle of last century. Although large scale anion exchange has not been implemented, its application for the removal of hydrogen sulfide is feasible based on anion exchange principles. This research was designed to evaluate feasible options for controlling hydrogen sulfide from groundwater sources. The feasibility of using anion exchange was investigated through pilot-scale testing of four groundwater sources. In addition, the performance of typical and alternative chemical oxidizers to control hydrogen sulfide was evaluated.

Eighty percent of the 780 million people worldwide that access water from an unimproved source live in rural areas. In rural areas, water systems are often managed by community based organizations and many of these systems do not provide service at the designed levels. The Sustainability Analysis Tool developed in Chapter 2 can inform decision making, characterize specific needs of rural communities in the management of their water systems, and identify weaknesses in training regimes or support mechanisms. The framework was tested on 61 statistically representative geographically stratified sample communities with rural water systems in the Dominican Republic. The results demonstrated the impact that long term support by outside groups to support community management activities can improve sustainability indicators, including financial sustainability which is a significant issue throughout the world. When analyzing the financial sustainability of water systems, it is important to consider all life-cycle costs including the expenditures made by households. Chapter 3 analyzes financial and economic expenditures on water services in 9 rural and peri-urban communities in Burkina Faso. Data from household and water point surveys were used to determine: socio-economic status, financial and economic expenditures, and service levels received by each household. In Burkina Faso recurrent financial and economic expenditures on water service ranged between US$5 and US$9.5 per person per year, with cumulative costs approximately US$19.5 per person per year. The average expenditures on water in Burkina Faso were well above the affordability threshold used by World Bank demonstrating the need to improve subsidies in the water sector. The sustainability of water supply systems and the ability to ensure the health benefits of these systems is also influenced by the deficiencies in sanitation infrastructure. Unimproved sanitation can be a source of water contamination and a risk factor in water related disease. Furthermore, the effective management of community water supply infrastructure is not a sufficient condition for ensuring water quality and eliminating health risks to consumers. As a result water treatment technologies, such as ceramic water filters (CWFs), implemented and managed at the household level and combined with safe storage practices are proposed as a means of reducing these risks. The performance of CWFs in laboratory settings has differed significantly from field studies with regard to microbial treatment efficacy and also hydraulic efficiency. Chapter 4 presents a 14 month field study of two locally manufactured CWFs conducted in a rural community in the Dominican Republic. Each of the 59 households in the community received one filter. The CWFs in this study performed poorly with regard to water quality and hydraulic performance. Focus group meetings and household survey suggests that flow rate is a major issue for user acceptability. To address the user concerns Chapter 5 presents two mathematical models for improving the hydraulic performance for the frustum and paraboloid designs. The models can be used to predict how changes in user behavior or filter geometry affects the volume of water produced and therefore can be used as tools to help optimize filter performance.

Perchlorate contamination of drinking water sources in the United States is widespread and represents a public health concern. Biological treatment is an attractive option because perchlorate-reducing bacteria (PRB) are ubiquitous in the environment and can reduce perchlorate completely to chloride. Treatment of perchlorate-contaminated water in fixed-bed bioreactors has been demonstrated at the laboratory- and pilot-scale. However, full-scale development of reliable biological drinking water treatment processes requires a better understanding of the microbial ecology and activity of perchlorate-reducing communities in bioreactors. The objective of this research was to develop molecular biology tools (MBTs) to quantify PRB and expression of genes required for complete perchlorate reduction (pcrA and cld). The development of MBTs targeting specific genes requires that the sequence of the genes be known. In this work, an MBT called prokaryotic Suppression Subtractive Hybridization (SSH) PCR complementary DNA (cDNA) Subtraction was developed to rapidly isolate target genes for sequencing. This new tool was developed and validated using the model bacterium Pseudomonas putida mt-2 and the model pollutant toluene. For this system, over 90% of the isolated gene fragments encoded toluene-related enzymes, and 20 distinct toluene-related genes from three key operons were identified. Based on these results, prokaryotic SSH PCR cDNA Subtraction shows promise as a targeted method for gene identification; however, application to a PRB did not yield new pcrA and cld sequences. Therefore, to support the development of biological perchlorate treatment processes, quantitative PCR (qPCR) and reverse transcription qPCR (RT-qPCR) assays targeting pcrA and cld were developed using existing sequences. The qPCR and RT-qPCR assays were applied to a laboratory-scale bioreactor and two pilot-scale bioreactors treating perchlorate-contaminated water. Higher quantities of perchlorate reduction genes and transcripts generally were observed when bioreactor performance was superior. Although no quantitative correlations were established, these assays detected differences in the quantity of PRB and changes in gene expression levels during the course of bioreactor operation and between bioreactors with different performance levels. Furthermore, these assays provided an additional line of evidence that microbial perchlorate reduction was occurring. This marks the first application of qPCR assays to quantify perchlorate reduction genes and transcripts in bioreactors. / text

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

M. Tech. Chemical Engineering / The lack of clean and fresh water has become a worldwide problem because of water pollution caused by industrialization. Contamination of natural water sources by heavy metal is a worldwide public health problem, leading to waterborne outbreaks of infectious hepatitis, viral gastroenteritis, and cancer. Therefore it very important to remove these toxic metal ions from municipal and industrial effluents in order to protect plants, animals and human beings from their adverse effect before discharging into natural water bodies. Although, several separation methods such as filtration, reverse osmosis and membrane technology have been developed to remove these toxic heavy metal ions from wastewater, however these conventional treatments technologies were found to be expensive on a sustainable basis. Adsorption process was identified as the most effective, and extensively used essential process in wastewater treatment, and in order for adsorption process to feasibly remove pollutants from wastewater, there should be a need for a suitable adsorbent which will have a large porous surface area, and a controllable porous structure. Through the application of nanotechnology, nano adsorbents can be developed as effective adsorbents to treat wastewater. The main objective of this project was to apply magnetic metal doped iron oxides as an efficient adsorption media for the removing of Cr(VI), Cd(II) and V(V) ions from wastewater.

In rural Bangladesh, the drinking water supply is mostly dependent upon manually operated hand pumped tubewells, installed by the local community. The presence of natural arsenic (As) in groundwater and its wide scale occurrence has drastically reduced the safe water access across the country and put tens of millions of people under health risk. Despite significant progress in understanding the source and distribution of As and its mobilization through sediment-water interactions, there has been limited success in mitigation since the problem was discovered in the country’s water supply in 1993. This study evaluated the viability of other kinds of alternative safe drinking water options and found tubewells are the most suitable due to simplicity and technical suitability, a wide acceptance by society and above all low cost for installation, operation and maintenance. During planning and decision making in the process of tubewell installation, depth of the tubewell is a key parameter as it is related to groundwater quality and cost of installation. The shallow wells (usually &lt; 80m) are mostly at risk of As contamination. One mitigation option are deep wells drilled countrywide to depths of around 250 m. Compared to safe water demand, the number of deep wells is still very low, as the installation cost is beyond affordability of the local community, especially for the poor and disadvantaged section of the society. Using depth-specific piezometers (n=82) installed in 15 locations spread over the 410 km2 area of Matlab (an As-hot spot) in southeastern Bangladesh, groundwater monitoring was done over a 3 year period (pre- and post-monsoon for 2009-2011 period). Measurements were performed for hydrogeological characterization of shallow, intermediate deep and deep aquifer systems to determine the possibility of targeting safe aquifers at different depths as the source of a sustainable drinking water supply. In all monitoring piezometers, As was found consistently within a narrow band of oscillation probably due to seasonal effects. Hydrogeochemically, high-As shallow groundwaters derived from black sands are associated with elevated DOC, HCO3, Fe, NH4-N and PO4-P and with a relatively low concentration of Mn and SO4. Opposite to this, shallow aquifers composed of red and off-white sediments providing As-safe groundwater are associated with low DOC, HCO3, Fe, NH4-N and PO4-P and relatively higher Mn and SO4. Groundwaters sampled from intermediate deep and deep piezometers which were found to be low in As, are characterized by much lower DOC, HCO3, NH4-N and PO4-P compared to the shallow aquifers. Shallow groundwaters are mostly Ca-Mg-HCO3 type and intermediate deep and deep aquifers’ groundwaters are mostly Na-Ca-Mg-Cl-HCO3 to Na-Cl-HCO3 type. A sediment color tool was also developed on the basis of local driller’s color perception of sediments (Black, White, Off-white and Red), As concentration of tubewell waters and respective color of aquifer sediments. A total of 2240 sediment samples were collected at intervals of 1.5 m up to a depth of 100 m from all 15 nest locations. All samples were assigned with a Munsell color and code, which eventually led to identify 60 color varieties. The process continued in order to narrow the color choices to four as perceived and used by the local drillers for identification of the targeted As-safe aquifers. Munsell color codes assigned to these sediments render them distinctive from each other which reduces the risk for misinterpretation of the sediment colors. During the process of color grouping, a participatory approach was considered taking the opinions of local drillers, technicians, and geologists into account. In addition to the monitoring wells installed in the piezometer nests, results from 87 other existing drinking water supply tubewells were also considered for this study. A total of 39 wells installed in red sands at shallow depths producing As-safe water providing strong evidence that red sediments are associated with As-safe water. Average and median values were found to be less than the WHO guideline value of 10 μg/L. Observations for off-white sediments were also quite similar. Targeting off-white sands could be limited due to uncertainty of proper identification of color, specifically when day-light is a factor. Elevated Mn in red and off-white sands is a concern in the safe water issue and emphasizes the necessity of a better understanding of the health impact of Mn. White sediments in shallow aquifers are relatively uncommon and seemed to be less important for well installations. Arsenic concentrations in more than 90% of the shallow wells installed in black sands are high with an average of 239 μg/L from 66 wells installed in black sediments. It is thereby recommended that black sands in shallow aquifers must be avoided. This sediment color tool shows the potential for enhancing the ability of local tubewell drillers for the installation of As-safe shallow drinking water tubewells. Considering the long-term goal of the drinking water safety plan to provide As-safe and low-Mn drinking water supply, this study also pioneered hydrogeological exploration of the intermediate deep aquifer (IDA) through drilling up to a depth of 120 m. Clusters of tubewells installed through site optimization around the monitoring piezometer showed a similar hydrochemical buffer and proved IDA as a potential source for As-safe and low-Mn groundwater. Bangladesh drinking water standard for As (50 µg/L) was exceeded in only 3 wells (1%) and 240 wells (99%) were found to be safe. More than 91% (n=222) of the wells were found to comply with the WHO guideline value of 10 µg/L. For Mn, 89% (n=217) of the wells show the concentration within or below the previous WHO guideline value of 0.4 mg/L, with a mean and median value of 0.18 and 0.07 mg/L respectively. The aquifer explored in the Matlab area shows a clear pattern of low As and low Mn. The availability of similar sand aquifers elsewhere at this depth range could be a new horizon for tapping safe drinking water at about half the cost of deep tubewell installation. All findings made this study a comprehensive approach and strategy for replication towards As mitigation and scaling-up safe water access in other areas of Bangladesh and elsewhere having a similar hydrogeological environment. / <p>QC 20151211</p> / Sida-SASMIT project (Sida Contribution 75000854).

Access to clean and safe drinking water is a fundamental human requirement. However, in many areas of the world natural water sources have been impacted by a variety of biological and chemical contaminants. The ingestion of these contaminants may cause acute or chronic health problems. To prevent such illnesses, many technologies have been developed to treat, disinfect and supply safe drinking water quality. However, despite these advancements, water supply distribution systems can adversely affect the drinking water quality before it is delivered to consumers. The primary aim of this research was to investigate the effect that water distribution systems may have on household drinking water quality in Christchurch, New Zealand and Addis Ababa, Ethiopia. Water samples were collected from the source water and household taps in both cities. The samples were then tested for various physical, chemical and biological water quality parameters. The data collected was also used to determine if water samples complied with national drinking water quality standards in both countries. Independent samples t-test statistical analyses were also performed to determine if water quality measured in the samples collected from the source and household taps was significantly different. Water quality did not vary considerably between the source and tap water samples collected in Christchurch City. No bacteria were detected in any sample. However, the pH and total iron concentrations measured in source and tap water samples were found to be significantly different. The lower pH values measured in tap water samples suggests that corrosion may be taking place in the distribution system. No water samples transgressed the Drinking Water Standards for New Zealand (DWSNZ) MAVs. Monitoring data collected by the Christchurch City Council (CCC) was also used for comparison. A number of pH, turbidity and total iron concentration measurements collected by the CCC in 2011 were found to exceed the guideline values. This is likely due to structural damage to the source wells and pump-stations that occurred during the 2011 earthquake events. Overall, it was concluded that the distribution system does not adversely affect the quality of Christchurch City’s household drinking water. The water quality measured in samples collected from the source (LTP) and household taps in Addis Ababa was found to vary considerably. The water collected from the source complied with the Ethiopian (WHO) drinking water quality standards. However, tap water samples were often found to have degraded water quality for the physical and chemical parameters tested. This was especially the case after supply interruption and reinstatement events. Bacteria were also often detected in household tap water samples. The results from this study indicate that water supply disruptions may result in degraded water quality. This may be due to a drop in pipeline pressure and the intrusion of contaminants through the leaky and cross-connected pipes in the distribution network. This adversely affects the drinking water quality in Addis Ababa.

Per- and polyfluoroalkyl substances (PFASs) are chemicals that have been used for over 50 years. They are both hydrophobic and hydrophilic, which make them useful in a wide range of products, both in the domestic and industrial market. Recently, the global attention on PFASs has increased due to their possible harmful health effects on humans. Furthermore, PFASs have been detected in drinking water sources all over the world. Conventional treatment processes in drinking water treatment plants (DWTPs) are not able to remove PFASs. Therefore, more research is required to find efficient removal techniques for these compounds. The aim of this study was to investigate the removal efficiency of PFASs using two different adsorption techniques, anion exchange (AE) with the resin Purolite A-600, and granular activated carbon (GAC) of type Filtrasorb®400. The experiments were performed in laboratory batch-scale, at Swedish University of Agriculture (SLU), and column tests in pilot-scale, at Bäcklösa DWTP in Uppsala. The PFASs showed a high sorption potential to AE and GAC. However, the removal efficiency differed depending on the perfluorocarbon chain length, functional group, and concentration level. For the AE, in average 92 % of the PFASs were removed in the end of the batch experiments while the average removal efficiency in the column experiment was 86 %. In the batch experiments treated with GAC on average 55 % of the PFASs were removed in the end of the experiments while the column experiment had the average removal efficiency of 86 %. There was an increase in the removal efficiency with increasing perfluorocarbon chain length in the column experiments. However, in the batch experiments, the adsorption of PFASs decreased with an increasing chain length, except for the highest PFAS concentration level (5000 ng L-1) treated with AE and the lowest PFAS concentration level (200 ng L-1) treated with GAC. In the column experiments, the perfluoroalkane sulfonates (PFSAs) were slightly better removed than perfluoroalkyl carboxylates (PFCAs) with an average removal efficiency of 97 % for AE and 91 % for GAC compared to 67 % and 82 % for AE and GAC, respectively. In the batch experiments, there was no clear trend between the removal efficiency and functional group. Overall, the pilot-scale experiments removed the PFASs relatively well even after 42 days (on average, 86 % for both AE and GAC). The lowest removal capacity in the column experiments was seen for the shorter chained PFSAs (in average 46 % for ≤C6 PFCAs using AE and 75 % for ≤C7 PFCAs using GAC). More efficient treatment techniques are needed to minimise the PFAS concentrations in drinking water and the potential human. / Per- och polyfluorerade alkylsubstanser (PFASs) är kemikalier som har används globalt under de senaste 50 åren. Tack vare att de är uppbygda av både en hydrofob och en hydrofil del är de ytaktiva (s.k. surfaktanter) och har ett brett användningsområde, både för industri- och hushållsprodukter. På senare år har dessa ämnen fått uppmärksamhet på grund av att exponering för PFASs har visats kunna medföra hälsorisker. PFASs har upptäckts i dricksvatten på många håll i världen, men flera av de konventionella reningsmetoderna för dricksvatten är inte effektiva för PFASs och därför finns ett behov av mer forskning och kunskap inom vattenberedningsområdet. I denna studie undersöktes reningseffektiviteten för PFASs hos två adsorptionstekniker; i) anjonbyte (AE) med Purolite A-600 och ii) granulerat aktivt kol (GAC) med Filtrasorb®400. Studien utformades så att inverkan av kolkedjans längd, molekylens funktionella grupp samt koncentrationsnivån av PFASs kunde utvärderas. Experimenten utfördes både i liten skala genom försök i bägare på Sveriges lantbruksuniversitet (SLU) och i något större skala i en pilotanläggning med kolonnexperiment på Bäcklösa dricksvattenverk i Uppsala.  Båda reningsmetoderna visade god effekvititet för avlägsnandet av PFASs i dricksvatten. I slutet av bägarexperimenten var i medeltal 92 % och 55 % av PFASs eliminerade för de prover behandlade med AE respektive GAC. Reningseffektivititen för kolonnexperimenten var i medeltal 86 % för båda metoderna. Reningsgraden var beroende av längden på den perfluorerade kolkedjan. I kolonnexperimenten visades att ökad kedjelängd ledde till ökad reningseffektivitet, medan bägarexperimenten visade på motsatt trend, med undantag för prover behandlades med AE och PFAS-koncentration 5000 ng L-1 samt prover behandlade med GAC och PFAS-koncentration 200 ng L-1. Reningseffektiviteten varierade också beroende på funktionell grupp, d.v.s. beroende på om det var en sulfonat eller en karboxylat. I kolonnexperimenten avlägsnades de perfluorerade alkylsulfonaterna (PFSAs) i något högre grad (97 % och 91 %; AE och GAC) än karboxylaterna (PFCAs; 67 % och 82 %; AE och GAC). För bägarexperimenten hittades dock inget tydligt motsvarande samband. Sammanfattningsvis renades PFASs från dricksvattnet i kolonnexperimenten relativt väl även i slutet av experimentent (efter 42 dagar). De sämst renade PFAS ämnena var de med kortare kolkedja. Efter 42 dagar hade PFCAs med kolkedjelängd ≤C6 renats bort med 46 % (AE) och på PFCAs med kolkedjelängd ≤C7 med 75 % (GAC). Behovet av bättre reningsmetoder för dessa PFASs är därför stort.

published_or_final_version / abstract / toc / Chemistry / Master / Master of Philosophy