Natural organic matter (NOM) is present in all surface waters as a result of decaying vegetation, biological activity, and organic soil. Alternative NOM removal processes such as anion exchange resins (AERs) have shown NOM removals typically ranging between 50 to 90%, with up to 99% removal achieved in some cases. The first portion of this study evaluated the performance of two AERs; a conventional Type 1 AER and magnetic ion exchange resin (i.e. MIEX®) for NOM removal from surface water quantified by UV254, dissolved organic carbon (DOC), and specific UV absorbance (SUVA). Samples were also characterized for chloride, sulphate, and chloride-to-sulphate mass ratio (CSMR) to provide additional information on water quality characteristics of AER treated waters. Overall, the results showed that both AERS were effective for removing NOM. However, the MIEX® resin provided greater removal of NOM with shorter contact times compared to the conventional resin investigated. Water treated with MIEX® resin showed significantly higher chloride and lower sulphate concentrations than the conventional AER. Higher CSMR values were found with MIEX® treated water compared to conventional AER system, although both resins showed CSMR much greater than 0.5, which can increase galvanic corrosion effects with lead. Bench-scale jar tests were conducted to investigate the impact of temperature on the efficacy of three NOM removal treatment technologies; enhanced coagulation with alum, MIEX® and a combined MIEX® treatment followed by coagulation with a low dose of alum. Higher settled water turbidity was observed during cold water operating conditions for all three processes. At cold-water operating conditions, DOC removal was reduced with combined MIEX® -Alum treatment, and UV254 removal was impacted for both MIEX® and MIEX® -Alum processes. The combined MIEX®-Alum process was found to provide the lowest THMFP and HAAFP at both temperatures to concentrations lower than current regulatory maximum acceptable concentration (MAC) guidelines in Canada. Surface charge analysis experiments were performed at bench-scale using synthetic water containing humic acid to determine the relationship between NOM and the charge of AER-treated waters. Further bench and pilot-scale studies were performed to investigate the use of surface charge measurements to monitor and optimize NOM removal during treatment with AER systems. Strong correlations were observed between UV254 and respective charge measurements (i.e. ZP, SC) of AER-treated synthetic and raw waters. The results of this research has shown that it is possible to use charge to optimize the MIEX® process for NOM removal. Additionally, it was found that SC measurements could be used as an operational tool for AER processes, where deviations in SC from optimum treatment would indicate the requirement for fresh resin addition or resin regeneration.

In order to improve the water situation in rural areas of Bangladesh, a research group at the University of Dhaka has been developing low cost domestic methods to remove pathogens from surface water through pasteurisation using free solar energy. Pasteurisation is a process in which water is heated to approximately 60 °C and maintained for about 30 minutes to destroy pathogens. In these methods, the water is also exposed to UV-light from the sunshine, which causes destruction of diarrhoeal pathogens at temperatures somewhat lower than required in normal pasteurisation. However, despite many advantages these devices need to be installed for each time of use. Recently, a semi-permanent device has been developed which is expected to be more user friendly. The objective of this Master thesis has been to study and optimize the low cost semi-permanent device that can deliver safe drinking water to people in rural areas. Two test devices were constructed to determine the most effective treatment e.g. temperature, time, solar radiation, user-friendliness and cost. To replicate the results from the solar heating tests a model, based on the solar radiation and convective heat loss from the device, was used. The model was also able to determine the time duration at a certain solar radiation level to estimate when the water is safe to drink. The results revealed that the performance of the device depends on thickness of the insulation and thickness of the air gap. This is because the most important factors to achieve safe drinking water are solar radiation and time. The modelling indicated that the measured water temperature corresponds well with the calculated water temperature and also showed that the lowest required solar radiation is 390 W/m2 to reach drinking water criteria, at an air temperature of 25 °C. A study of microbiology showed that the semi-permanent low cost device could purify surface water to a safe level.

The occurrence of As in groundwater in Argentina was known since 1917; however, the occurrence, distribution and mobilization of As and other trace elements (TEs) in groundwater in the Bolivian Altiplano are still quite unknown. An investigation applying a geochemical approach was conducted in the Poopó Basin and Lake Titicaca to understand processes of TEs in different systems such as water, soils, crops and sediments in mining areas. In Poopó Basin,As, Cd and Mn concentrations exceed World Health Organization (WHO) guidelines and Bolivian regulations for drinking water in different places around the basin, but Cu, Ni, Pb and Zn do not. In soils, the sequential extraction methods extracted up to 12% (fractions 1 and 2), which represent &lt; 3.1 mg/kg of the total As content, as potentially mobilized fractions, that could be transferred to crops and/or dissolved in hydrologic system. The large pool of As can be attached due to amorphous and crystalline Fe oxide surfaces (fractions 3, 4, and 5) present in the soils. Furthermore, the concentrations of As, Cd and Pb in the edible part of the crops revealed that the concentrations of As and Cd do not exceed the international regulation (FAO, WHO, EC, Chilean) (0.50 mg/kgfw for As and 0.10 mg/kgfw for Cd), while Pb exceeds the international regulations for beans and potatoes (for beans 0.20 mg/kgfw and for potato 0.10 mg/kgfw). In the Lake Titicaca, principal component analysis (PCA) of TEs in sediments suggests that the Co-Ni-Cd association can be attributed to natural sources such as rock mineralization, while Cu-Fe-Mn come from effluents and mining activities, whereas Pb-Zn are mainly related to mining activities. The Risk Assessment Code (RAC) indicate “moderately to high risk” for mobilization of Cd, Co, Mn, Ni, Pb and Zn, while Cu and Fe indicate “low to moderate risk” for remobilization in the water column. / <p>QC 20140604</p> / Hydrochemistry: Arsenic and heavy metals in the Lake Poopó Basin (Sida contribution: 7500707606) / Catchment Management and Mining Impacts in Arid and semi-arid South America (CAMINAR) (INCO-CT-2006-032539)

This study gives insight to the origin of pollution in the water resources of the Limpopo province of South Africa. The Limpopo province is the largest rural province in South Africa. Up to 40% of the total population does not have access to sufficient water supply, resulting in adverse health effects. The purpose of this study is to determine (1) the degree of inorganic pollution of borehole water; (2) to identify the pollution sources, and (3) to determine whether the pollution is inherited from the surface water that recharges the groundwater or is caused on site near the bore holes. In order to achieve these objectives, surface water quality data (14 675 samples) and borehole water data (340 samples) at health facilities were analysed. A pollution index, defined by the following ratio: Pollution index (%) = 100 x ([Cl–] + 2[SO4^-2] + [NO3-] + 3[PO4^-3]) ÷ ([Cl-] + 2SO4^-2 + [NO3-] + [PO4^-3] + [HCO3-]) was used to determine the percentage of contribution of each chemical species towards pollution. This ratio is based on the fact that bicarbonate is released during chemical weathering of rocks whereas sulphate, nitrate, chloride, and phosphate are anthropogenic in origin. The pollution index shows that 6% of the surface waters and 21% of the borehole water is severely polluted. The pollution of the surface water is characterized by high concentrations of sulphate whereas the pollution of the borehole water is characterized by high concentrations of chloride. This indicates that the pollution of the borehole water is not so much the result of the infiltration of polluted surface water, but rather the result of on–site pollution on the surface near the bore holes. / Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2011.

This study gives insight to the origin of pollution in the water resources of the Limpopo province of South Africa. The Limpopo province is the largest rural province in South Africa. Up to 40% of the total population does not have access to sufficient water supply, resulting in adverse health effects. The purpose of this study is to determine (1) the degree of inorganic pollution of borehole water; (2) to identify the pollution sources, and (3) to determine whether the pollution is inherited from the surface water that recharges the groundwater or is caused on site near the bore holes. In order to achieve these objectives, surface water quality data (14 675 samples) and borehole water data (340 samples) at health facilities were analysed. A pollution index, defined by the following ratio: Pollution index (%) = 100 x ([Cl–] + 2[SO4^-2] + [NO3-] + 3[PO4^-3]) ÷ ([Cl-] + 2SO4^-2 + [NO3-] + [PO4^-3] + [HCO3-]) was used to determine the percentage of contribution of each chemical species towards pollution. This ratio is based on the fact that bicarbonate is released during chemical weathering of rocks whereas sulphate, nitrate, chloride, and phosphate are anthropogenic in origin. The pollution index shows that 6% of the surface waters and 21% of the borehole water is severely polluted. The pollution of the surface water is characterized by high concentrations of sulphate whereas the pollution of the borehole water is characterized by high concentrations of chloride. This indicates that the pollution of the borehole water is not so much the result of the infiltration of polluted surface water, but rather the result of on–site pollution on the surface near the bore holes. / Thesis (M.Sc. (Geography and Environmental Studies))--North-West University, Potchefstroom Campus, 2011.

Water quality is of great importance for ecosystems and society. This thesis characterized and modeled the variation in several key constituents of Swedish surface waters, with particular consideration given to intra-annual variability and sensitivity to climate change. Cyanobacterial data from 29 lakes and basins as well as total organic carbon (TOC) from 215 watercourses were used. Extensive data on catchment characteristics, morphometry, discharge, temperature and other water chemistry data were also analyzed. Models characterizing the seasonality in cyanobacterial concentration and relative cyanobacterial abundance were developed with common lake variables. Concentrations of TOC, iron and absorbance were simulated using discharge, seasonality and long-term trend terms in the Fluxmaster modeling system. Spatial patterns in these model terms were investigated, and the sensitivity of cyanobacteria and TOC to future climate was explored. Nutrients were the major control on cyanobacterial concentration seasonality, while temperature was more important for relative cyanobacterial abundance. No cyanobacterial blooms occurred below a total phosphorus threshold of 20 µg l-1. Discharge and seasonality explained much of the intra-annual variability in TOC, but catchment characteristics could only explain a limited amount of the spatial patterns in the sensitivity to these influences. North of Limes Norrlandicus the discharge term had a larger impact on the TOC concentration in large catchments than in small catchments, while south of Limes Norrlandicus the seasonality had a larger impact in small catchments than in larger catchments. According to the climate change scenarios, both TOC and cyanobacterial concentrations will be higher in the future. The cyanobacterial dominance will start earlier and persist longer. The spring TOC concentration peak will come earlier. The changes in TOC loads are more uncertain due to predicted declines in discharge. Parsimonious statistical regression models could explain observed variability in cyanobacteria and TOC. For predictions, these models assume that future aquatic ecosystems will exhibit the same sensitivity to major drivers as in the past. If this proves not to be the case, the modeling can serve as a sentinel for changing catchment function as indicated by degradation in model performance when calibrations on older data are used to model later observations.

Landfills are a major potential source of groundwater and surface-water contamination. The compounds that can leach from landfilled materials include dissolved organic matter, inorganic macrocomponents, heavy metals, and xebobiotic organic compounds. Landfill surface-water runoff poses a threat to the environment due to high mobility, but has not been rigorously characterized with regards to common pollutants found in landfills. It is well documented that constructed wetlands can serve as an effective treatment option for many pollutants found in landfills. The Napanee Landfill has constructed a wetland in order to treat surface-water runoff coming off the landfill. The objectives of this study were to: 1) characterize the water chemistry of surface-water runoff for an inactive landfill; 2) evaluate the treatment potential for the constructed wetland system at the Napanee Landfill; and, 3) recommend design, maintenance, and operative improvements to enhance effluent water quality. The analysis of the landfill surface-water runoff entering the Napanee Landfill constructed wetland included the pollutants nitrate, ammonia, sulphate, phosphorus, and chloride. The median inflow and outflow concentrations for all of the observed pollutants did not exceed Canadian federal or provincial water quality guidelines. There were sampling days where ammonia, phosphorus, and chloride exceeded guidelines at the inflow and days where ammonia and chloride exceeded guidelines at the outflow. The only pollutant that saw a statistically significant decrease in concentrations was sulphate, with a change of 38% from the inflow to the outflow. Other changes of note were nitrate and phosphorus concentrations increasing by 50% and 23% respectively from the inflow to the outflow. There are a variety of improvements that can be made to the Napanee Landfill constructed wetland that would increase the treatment efficiency of ammonia. Incorporating a vertical-flow wetland would increase available surface area for nitrifying bacteria growth and would provide more oxygen for nitrification processes; both would increase the potential for significant ammonia treatment. Overall, the concentrations of the pollutants found in the surface-water runoff coming off of the Napanee Landfill constructed wetland did not pose a significant threat to the environment at the time of sampling and treatment processes were only successful in reducing sulphate pollutant concentrations.

Hydration is known to be crucial in biomolecular interactions including ligand binding and self-assembly. In our earlier studies we have shown the key role of water in stabilizing the specific parts of the collagen triple helix depending on the imino acid content. We further showed that the primary hydration shell around collagen could act as a lubricating layer aiding in collagen assembly. But key details on the structure and dynamics of water near protein surfaces and its role in protein-protein interactions remain unclear. In the current study we have developed a novel method to analyze hydration maps around peptides at 1-A resolution around three self-assembling lament systems with known structures, that respectively have hydrated (collagen), dry non-polar and dry polar (amyloid) interfaces. Using computer simulations, we calculate local hydration maps and hydration forces. We find that the primary hydration shells are formed all over the surface, regardless of the types of the underlying amino acids. The weakly oscillating hydration force arises from coalescence and depletion of hydration shells as two laments approach, whereas local water diffusion, orientation, or hydrogen bonding events have no direct effect. Hydration forces between hydrated, polar, and non-polar interfaces differ in the amplitude and phase of the oscillation relative to the equilibrium surface separation. Therefore, water-mediated interactions between these protein surfaces ranging in character from ‘hydrophobic’ to ‘hydrophilic,’ have a common molecular origin based on the robustly formed hydration shells, which is likely applicable to a broad range of biomolecular assemblies whose interfacial geometry is similar in length scale to those of the present study. In a related study through simulations we show that the rate of tissue optical clearing by chemical agents correlated with the preferential formation of hydrogen bond bridges between agent and collagen. Hydrogen bond bridge formation disrupts the collagen hydration layer and facilitates replacement by a chemical agent to destabilize the tertiary structure of collagens thereby reducing light scattering. This study suggests that the clearing ability of an alcohol not only depends on its molecular size, but also on the position of hydroxyl groups on its backbone.

Both rice production and fish culture in the Mekong Delta, Vietnam have a close mutual relationship with the use of water and land resources. First, they are competitive in the use of land and water. Second, rice production discharges pesticides into water bodies causing an external cost to fish culture, which, in turn, leads to an increase in fish cost and price. A dynamic model for maximizing the social surplus is developed for optimal management of resources as well as production. Its first-order conditions provide some important quantitative as well as qualitative interpretation that explains the dynamic relationships among prices, water quality, and shadow price. The time paths and phase diagrams of the model show the variations and the changes in prices, outputs, and water quality over time, and the initial position in regions leading to divergence or convergence. As a result, effective policies are set up to maximize social welfare. Data are collected and used in estimations of demand functions of rice and fish, the function of assimilative capacity, the fish cost function, and the parameter of pesticide discharge. The total loss of fish culture (total external cost in the year 2001) due to pesticide use is about 9 billion $US. Two cases of linear and nonlinear forms are simulated with scenarios of initial values for the year 2001. The simulation shows optimistic results with prices going down and water quality going up over time, meaning the social surplus will rise. The phase diagram shows that the social manager should look for policies to raise the initial value of water quality to get an optimal solution. A comparative analysis of the model simulation shows the directions of change in parameters leading to a change in the steady state values. How to change the parameter values is analyzed and the analysis suggests different policies.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.