Anthropogenic climate change will impact Virginia's hydrologic processes in unforeseen ways in the coming decades. This research describes variability in meteorology (temperature and precipitation) and associated hydrologic processes (evapotranspiration) throughout an ensemble of 31 general circulation models (GCMs) used by the Chesapeake Bay Program (CBP). Trends are compared with surface runoff generation patterns for a variety of land uses to investigate climate's effect on runoff generation. Scenarios representing pairings of the tenth, fiftieth, and ninetieth percentiles of precipitation and temperature in the CBP 31-model ensemble were run through VADEQ's VA Hydro hydrologic model to investigate streamflow's response to climate. Temperature changes across the study area were minimized in the tenth percentile scenario (+1.02 to +1.24◦C) and maximized in the ninetieth (+2.20 to +3.02◦C), with evapotranspiration change following this trend (tenth: +2.84 to +3.81%; ninetieth: +6.53 to +10.2%). Precipitation change ranged from -10.9 to -7.30% in the tenth to +22.1 to +28.0% in the ninetieth. Runoff per unit area was largely dependent on land use, with the most extreme changes in runoff often seen in forested and natural land uses (-24% in tenth; +53% in ninetieth) and the least extreme seen in impervious and feeding space land(tenth: -11%; ninetieth: +30%). Both overall runoff per unit area and streamflow changed drastically from the base in the tenth (-20.4% to -25.9% change in median runoff; -19.8% to -27.1% change in median streamflow) and ninetieth (+30.4% to +53.7% change in median runoff; +33.0% to +77.8% change in median streamflow) percentile scenarios. / Master of Science / Human-caused climate change will impact Virginia's hydrologic processes in unforeseen ways in the coming decades. This research describes variability in meteorology (temperature and precipitation) and associated hydrologic processes (evapotranspiration) throughout an ensemble of 31 general circulation models (GCMs) used by the Chesapeake Bay Program (CBP). Trends are compared with surface runoff generation patterns for a variety of land uses to investigate climate's effect on runoff generation. Scenarios representing pairings of the tenth, fiftieth, and ninetieth percentiles of precipitation and temperature in the CBP 31-model ensemble were run through VADEQ's VA Hydro hydrologic model to investigate streamflow's response to climate. Temperature changes across the study area were minimized in the tenth percentile scenario (+1.02 to +1.24◦C) and maximized in the ninetieth (+2.20 to +3.02◦C), with evapotranspiration change following this trend (tenth: +2.84 to +3.81%; ninetieth: +6.53 to +10.2%). Precipitation change ranged from -10.9 to -7.30% in the tenth to +22.1 to +28.0% in the ninetieth. Runoff per unit area was largely dependent on land use, with the most extreme changes in runoff often seen in forested and natural land uses (-24% in tenth; +53% in ninetieth) and the least extreme seen in impervious and feeding space land(tenth: -11%; ninetieth: +30%). Both overall runoff per unit area and streamflow changed drastically from the base in the tenth (-20.4% to -25.9% change in median runoff; -19.8% to -27.1% change in median streamflow) and ninetieth (+30.4% to +53.7% change in median runoff; +33.0% to +77.8% change in median streamflow) percentile scenarios.

The purpose of this research was to evaluate the rates, patterns, and pathways involved in the biodegradation of organic contaminants in subsurface environments. Subsurface material was obtained from ten sites in six geographical locations representing diverse environmental conditions. The overall goal was to gain a general understanding of biodegradative mechanisms rather than making site-specific measurements. The biodegradation rates of methanol, phenol, and <i>t</i>-butanol (TBA) were evaluated in static soil/water microcosms. Biodegradation assays were conducted under ambient anoxic conditions, and with the addition of potential electron acceptors (nitrate, nitrite, sulfate) or metabolic inhibitors (molybdate, BESA) to promote different pathways of anaerobic microbial metabolism (nitrate respiration/denitrification, sulfate reduction, or methanogenesis). In unamended systems, biodegradation rates varied considerably between sites. Methanol and phenol were degraded fairly readily. Rates generally ranged from 0.5 to 1.0 mgL⁻¹d⁻¹ for 20°C incubation. Disappearance of methanol and phenol followed zero- to first-order kinetics and was usually immediate, requiring no acclimation period. TBA was relatively recalcitrant in subsurface soils, disappearing at a rate of 0.1-0.3 mgL⁻¹d⁻¹ (20°C). No biodegradation was evident, relative to sterile controls, in certain soils. The pattern of TBA degradation was typically biphasic: a long lag period of slow, linear removal was followed by an abrupt increase in removal rate (albeit still slow). Biodegradation rates were positively correlated with bacterial density for 12 soil samples from 3 sites within a localized area at Blacksburg, Virginia. However, this relationship did not exist between soils from diverse locations. The prevailing electron acceptor conditions govern the catabolic pathways utilized in the anaerobic respiration of organic contaminants. The effects of the added electron acceptors and inhibitors on biodegradation rates varied between sites. Two general types of systems are indicated by relative biodegradation rates, characteristic responses to electron acceptor/inhibitor amendments, and general environmental conditions. "Fast" soils are characterized by a higher flux of water and nutrients, higher biodegradation rates, and rate enhancement upon adding nitrate or sulfate. In "slow" soils, organic contaminants are degraded at lower rates, rates are decreased by adding nitrate, sulfate, or BESA (which inhibits methanogenesis), and rates are increased by adding molybdate (which inhibits sulfate reduction). Nearly all soils tested were capable of sulfate-reducing and methanogenic metabolism, but those populations were more active, and competition between the two groups was less severe, in "fast" soils. In contrast, "fast" soils appeared to harbor an active population of nitrate respiring/denitrifying bacteria, whereas in "slow" soils that metabolic group was inactive, absent, or susceptible to nitrite toxicity. / Ph. D.

Groundwater contaminated by organic chemicals from industrial spills, leaking underground gasoline storage tanks and landfills has caused concern about the future of a major source of drinking water. Compounds from industrial sources such as alcohols and phenols are frequently found as groundwater contaminants. These compounds are highly soluble in water and do not adsorb well to aquifer material. They also have the potential to migrate in the subsurface system achieving significant levels in drinking water supplies. In addition, they can serve as carriers for carcinogenic compounds such as benzene, toluene and xylene which are relatively insoluble in water, but are quite soluble in alcohol. A potential alternative to expensive groundwater reclamation projects is the use of the natural soil bacteria to degrade organic contaminants. Very little is known, however, about subsurface soil bacteria to man-made organic chemicals or the degradation rates of these compounds. Such information would be useful in planning cleanup or protection strategies for groundwater systems. This study was designed to measure the kinetic response of tertiary butyl alcohol (TBA), determine the biological degradation rates of methanol, ethanol, propanol, l-butanol, TBA, pentanol, phenol and 2,4-dichlorophenol; describe site specific conditions which enhance or inhibit degradation and compare biodegradation rates with thermodynamic predictions. Laboratory microcosms utilizing soil from two previously uncontaminated sites of widely varying conditions were constructed to simulate the subsurface environment. Nitrate was added to some microcosms to stimulate denitrification and metabolic inhibitors were added to others to define conditions at each site which favor biodegradation. Each of the test compounds except TBA was readily degraded in the Blacksburg soil. Inhibition of sulfate reduction by the addition of molybdate stimulated degradation of all compounds including TBA, whereas, inhibition of methanogenesis with BESA slowed the degradation rates. The addition of nitrate did not affect the biodegradation in Blacksburg soil. In the Newport News soil, all of the test compounds were biodegraded at substantially higher rates than was observed in the Blacksburg soil. The presence of the metabolic inhibitors did not affect degradation, however, the addition of nitrate increased the degradation rates of the alcohols but not the phenols. The degradation rates in each of the soils did not correlate with the bacterial population size or free energies of the reactions. / Ph. D.

Thesis (MBA)--Stellenbosch University, 2005. / Some digitised pages may appear illegible due to the condition of the original hard copy / ENGLISH ABSTRACT: Water is essential for life. Like the very air that surrounds us the omnipresent and indispensable qualities of water pervade throughout all of our lives. For reasons of health, community and trade the beginnings of all civilisations were proximate to the mighty rivers of the world. In a rapidly expanding global village, the priority for our future is to secure the management of increasing levels of water demand, given the finite natural cycle that all water is subject to and derived from; the hydrological cycle. The focus of this papers investigation is how best to allocate the value of water through the relatively nascent developments of water markets. The premise of utilising markets for allocative efficiency is suitably ingrained in the workings of many societies today, and the need to treat water with commensurate value and avoid waste is encapsulated in the Dublin Principles, where #4 states; 'Water has an economic value in all its competing uses and should be recognised as an economic good'. Which in isolation has merit, the legacy of state water management is usually associated with underperformance at best or incompetence and corruption at worst, and therefore the introduction of market mechanisms to provide water with allocative efficiency and true value, should be a positive undertaking for change. However the requisite conditions for proficient markets and perfect competition; which primarily include, that all agents are buyers and sellers, for a homogeneous product, with perfect information, without externalities, after the full and fair assignment of property rights, where all goods and services are private goods, and where transaction costs remain close to zero; would seldom be applicable to water. The many idiosyncrasies of water inhibit the application of competitive markets. Water could easily be defined as a public good with riparian rights, subject to a range of social and environmental externalities, whilst incurring high structural entry costs and remaining subject to the problematic vagaries of the natural supply cycle. Demand profiles also give water a heterogeneous definition, as domestic uses include both sanitation and drinking water, whilst various levels of quality are required for industry and agriculture, and even recreation. This paper seeks to define those factors that both warrant and limit the introduction of market functions to water management. The premise of this paper remains the search for better ways of valuing water, and how to incorporate fully the foundations of the environment and social criteria of health, and poverty reduction within these economic considerations. The conclusion defines a premium / discount solution to market traded water prices, which internalises these factors. / AFRIKAANSE OPSOMMING: Water is noodsaaklik vir lewe. Net soos die lug wat ons omring het water ook alomteenwoordige eienskappe wat In onskeibare deel van ons lewens vorm. Die ontstaan van alle beskawings is te vinde in die nabyheid van groot en gevestigde riviere vir redes van gemeenskaplikheid, gesondheid en handel. Vandag se geintegreerde en snel-groeiende samelewing met sy toenemende vraag na water, noodsaak 'n toekomsgerigte benadering om waterbronne te bestuur gegewe die vaste water natuursiklus waar water vandaan kom en bewaar word in. Die fokus van hierdie studie is om die beste metodes te vind vir waterallokasie met verwysing na die ontwikkeling van water markte oor die eeue. Die gebruik van die markstelsel om water effektief te allokeer is die grondslag van baie samelewings vandag. So erken die Dublin beginsels die noosaaklikheid om 'n waarde te plaas op water beklemtoon dat dit nie vermors moet word nie. Beginsel #4 bepaal: "Water het 'n ekonomiese waarde in al sy vele gebruike en moet ooreenkomstig erken word as ekonomiese saak". Die bestuur van waterbronne deur 'n owerheid word gewoonlik vereenselwig met 'n nie-optimale of selfs korrupte onbevoegdheid. Hier behoort die bekendstelling van mark beginsels om 'n waarde en nut op water te plaas dus 'n positiewe ontwikkeling te wees. Tog is dit ook duidelik dat die vereistes vir 'n effektiewe mark; alle agente is kopers en verkopers, 'n eenvormige produk, deursigtigheid in informasie, geen eksternaliteite, erkenning van besitreg, alle goedere en dienste is privaat goedere, transaksie koste is naby aan nul; nie volkome toepasbaar is op water nie. Die eenvoudige asook komplekse aard van water verhoed dat standaard markstelsel en beginsels van kompetisie eenvormig toepasbaar is. Water kan ook maklik gekategoriseer word as publieke goedere met gemeenskapsregte, wat dit dan onderhewig sal maak aan verskeie maatskaplike en omgewingsmaatreëls, hoë toetrede kostes, en logistieke probleme van die verskaffingsiklus. Dit is egter die vraag na water wat defineer dit as heterogene produk met huishoudelike gebruike vir beide persoonlike verbruik asook sanitasie, terwyl doelgerigte gebruike in landbou, handel en nywerheid ook spesifieke kwaliteite kan vereis. Hierdie werkstuk beoog om die faktore te defineer wat die bekendstelling van 'n mark stelsel vir water bestuur daarstel en ook beperk. Die uitgangspunt van hierdie studie was om maniere te vind vir beter ekonomiese waardasie van water en dit dan te kombineer met die fondasies van die omgewing, maatskaplike & gesondheidsmaatreëls, asook die toeganklikheid van basiese dienste aan almal.

Thesis (MPhil)--Stellenbosch University, 2006. / ENGLISH ABSTRACT: Urbanisation is a complex phenomenon and is a trend witnessed across the globe. Africa particularly has been experiencing the world’s most rapid rate of urbanization and cities are faced with the resulting pressure on natural resources. Water is one of the resources under pressure and the provision thereof is complicated by the deteriorating quality and quantity thereof. This study takes a brief look at the water situation in a water scarce region in Africa and concentrates on the urban water supply sector. It takes an in depth look at the measures used to secure water supply to a city in this very dry part of the world. The area under study is Windhoek, the capital of Namibia, situated in the southwestern corner of Africa. Namibia is the driest country in Sub-Saharan Africa and is characterised by a semi-arid nature, which results in a very hot and dry climate with erratic rainfall patterns. Windhoek has a low average rainfall associated with very high evaporation rates. No permanent water bodies exist near the city and the bulk of Windhoek’s water supply comes from storage dams quite a distance from the capital. Most of these sources of supply have been developed and are nearing the limit of their potential. A desperate need therefore exists to develop reliable additional water resources to secure the water supply especially during periods of prolonged drought. The case study gives examples of the initiatives taken by water authorities to improve the security of supply and keep up with the growing demand in the city. These initiatives include a dual pipe system for the distribution of semi-purified sewage for irrigation, reclamation of domestic sewerage, aquifer recharge and the implementation of Water Demand Management principles. An analysis of the most efficient and cost-effective means of supply augmentation namely aquifer recharge, have been balanced against the potential water savings of Water Demand Management in the city. The study also takes a brief look at the principles of Integrated Water Resource Management and how it is incorporated in the strategies used to augment supply to the city. The research found aquifer recharge as the most efficient and cost-effective means to augment supply to the city and together with Water Demand Management creates an approach complying with the goals of Integrated Water Resource management. The study concludes by identifying gaps in demand management in the city. It also suggests relevant recommendations on how to increase the effectiveness of Water Demand management. / AFRIKAANSE OPSOMMING: Verstedeliking is ‘n komplekse verskynsel en ‘n tendens wat regoor die wêreld voorkom. Die hoogste voorkoms van verstedeliking vind in Afrika plaas wat groot druk plaas op die natuurlike hulpbronne van stede. Water is een van die hulpbronne onder druk en die voorsiening daarvan word bemoeilik deur die verswakking van die kwaliteit en die beskikbaarheid daarvan. Hierdie studie konsentreer op die watersituasie in ‘n waterskaars streek in Afrika en die stedelike watervoorsieningssektor. Dit behels ‘n in diepte ondersoek na metodes wat gebruik word om die watervoorraad van die stad te verseker in hierdie droogte gesteisterd deel van die wêreld. Die gebied onder bespreking is Windhoek, die hoofstad van Namibië, wat geleë is in die Suidwestelike deel van Afrika. Namibië is die droogste land in die Sub-Saharastreek en word gekenmerk deur gereelde droogtes met ‘n gepaardgaande warm droë klimaat en onreëlmatige reënvalpatrone. Windhoek word gekenmerk deur ‘n lae gemiddelde reënval met ‘n baie hoë verdampingstempo. Geen permanente waterbronne kom in die nabyheid van die stad voor nie en die watervoorraad word gestoor in opgaardamme wat redelik ver van die hoofstad geleë is. Hierdie voorsieningsbronne is voortdurend in gebruik en die voorraad is beperk. Daar onstaan dus ‘n dringende behoefte aan betroubare bykomende waterbronne om voortdurende voorsiening aan die stad te verseker veral gedurende aanhoudende droogtes. Die gevallestudie konsentreer op voorbeelde en inisiatiewe wat deur die Water Owerhede geneem word om die voorsiening van water, aan die immergroeiende behoeftes van die stad te verbeter en te verseker. Hierdie pogings sluit in,‘n dubbele pyplynsisteem vir die verspreiding van halfgesuiwerde rioolwater vir besproeiingsdoeleindes, herwinning van huishoudelike rioolwater, herlaai van ondergrondse watervoorraad en die implimentering van wateraanvraag bestuursmaatreëls. Die geskiktste en mees koste-effektiewe metode van verhoogde watervoorsiening naamlik die herlaai van ondergrondse waterbronne, is ontleed, en die voordele opgeweeg teen die potensiële waterbesparing deur die Bestuur van Wateraanvraag in die stad. Daar is ook kortliks gekyk na die beginsels van Geintigreerde Water Bronne Bestuur en hoe dit by bestaande strategieë ingelyf is om uitbreiding van voorsiening aan die stad te verseker. Die navorsing het bevind dat die herlaai van ondergrondse waterbronne as die geskikste en mees koste-effektiewe metode beskou kan word om die verhoogde aanvraag van die stad die hoof te bied. Die studie word afgesluit deur die tekortkominge in die Water Aanvraagbestuur van die stad te identifiseer. Relevante aanbevelings word gemaak van hoe om die effektiwiteit van hierdie betrokke strategie te verbeter.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project. / A reprint of Water-Supp1y Paper 320, United States Geological Survey. United States Department of the Interior, being No. 3 cooperative, between United States Departments and the Arizona Agricultural Experiment Station. / Chapter on agriculture by R. H. Forbes

AECI Bioproducts (Bioproducts) is part of an industrial complex located at Umbogintwini, approximately 26 km south of Durban, Kwazulu-Natal. This system was selected for water pinch investigation, as it is one of the major users of freshwater on the complex and hence discharges a related quantity of wastewater, amounting to approximately 400 ML per annum. Bioproducts is a manufacturer of l-lysine, which is an animal feed additive. Water stream flowrate and purity data, as well as operating cost information, were obtained from plant records at AECI Bioproducts. Limiting flowrate and purity conditions for the water-using operations were established from a mass balance over the entire system using the Linnhoff-March software, WaterTracker. Subject to the specified constraints and operating costs, the problem was to determine the design of the water-using subsystem. No treatment plants were included in the study, as none exist at the facility. Three scenarios were investigated, which examined the operating variability of one of the evaporators on the site (the AS evaporator), which produces a condensate source of variable purity. The operating cost target and network design for each scenario was determined using the Linnhoff-March software, WaterPinch. Alterations from current operating practice were identified and associated savings (water-using network operating cost and freshwater flowrate) were highlighted. A robust optimal design was identified, with a recycle, which was consistent for all scenarios investigated. The degree of reuse of the AS evaporator condensate source was determined to be dependent on the purity of the source. The limiting constraint was identified at the sea pipeline, for suspended solids (SS): a prohibitively low discharge concentration constraint was identified as posing the major obstacle for saving. The potential for saving was investigated by incrementing the SS concentration constraint and subsequently the free and saline ammonia (FSA) constraint and allowing for the broth effluent to be discharged via the sea pipeline (which was previously disallowed by an effluent exemption). Although relatively small savings were identified through process integration (from 0.61% to 1.56% of the water-using network operating cost), the analysis identified a potential saving of over 70% of the water-using network operating cost, with relaxation of the sea pipeline SS and FSA constraint. / Theses (M.Sc.)-University of Natal, Durban, 2002.

MSc Dissertation Submitted to School of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, South Africa 12 August 2016 / Most mineral processing plants have high water requirements for their operational activities. These plants often function in an environment where water is becoming increasingly scarce. An increase in population will result in an increased demand for water, potentially beyond the limits of supply, and hence increased competition for the resource. In South Africa, Gauteng and the North West Province are likely to be first to experience a shortage of potable water. The key to a sustainable future lies in understanding and utilising resources more efficiently. This holds especially for industries who seek to minimise water usage through better management of resources. The two tools used in this study are the Water Accounting Framework (WAF) and Water Footprinting (WF) method. This research assisted a refinery in the North West Province understand its water usage and move towards operating in a more sustainable manner. Site water management was improved and the objective of this research fulfilled by: (i) Surveying the potable water and the storm water systems with a view to assessing the current water accountability and determining methods to improve accountability; (ii) Determining the water balance for the site and presenting it in the form of a water balance sheet; (iii) Reporting water usage in accordance with the Minerals Council of Australia’s “Water Accounting Framework for the Minerals Industry”; (iv) Calculating the water footprints of the refinery; and (v) Evaluating the water usage at the refinery and identifying ways in which water savings could be achieved. It was seen that the biggest consumer of water was the boilers and utilities section and the biggest loss of water was through evaporation. The refinery potable water requirement (2 280 m3/y) amounted to 0.16% of the daily water use for the Bojanala Platinum District. Four reports (outputs) were generated using the WAF. The four reports generated provide a good indication of the movement of water into, out of and during a process. WFs were calculated for the process. The blue WF was calculated to be 832 363 m3 and the green WF was calculated to be 261 970 m3. The product WF was 43.9 m3/t of base metal produced. There was no grey WF as the site does not discharge polluted water. This research provided an opportunity for the refinery to improve water efficiency onsite as well as improve reporting standards. Water usage was reported using global reporting tools to set a benchmark for the base metals industry. / MT2017

This paper presents the results of the spike tests performed in the alternative water supply pilot testing program for the City of Pembroke Pines. It establishes the effectiveness of a protocol that can be used to gain further insight on the rejection capacities of RO membranes. An in-depth study of the molecular descriptors affecting rejection by RO membranes is presented and used in the development of a discriminant function analysis. This analysis proved to be an effective way to predict the passage of Emerging Substances of Concern (ESOCs) through RO membrane. Further, a principal component (PC) analysis was performed to determine which factors accounted the largest variation in RO permeability. Additionally, this paper defines the groundwork for a discriminant analysis model that, if further developed, could serve as an important tool to predict the rejection capabilities of RO treatment when handling with ESOCs. / by Fernando J. Pleitez Herrera. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

A study conducted by the World Health Organization and United Nations Children's Fund, concluded that approximately 768 million people worldwide are not receiving sanitary drinking water suitable for consumption. While there are many water treatment methods, lime softening proves to be one of the more effective approaches as it removes a wide variety of harmful compounds including arsenic, lead, mercury, and cadmium under the correct conditions. The greatest issues with lime softening on a smaller scale include the complexity of the chemistry and need for monitoring. By designing the system for groundwater sources and with a smaller capacity, this thesis hoped to reduce the level of monitoring, chemical expertise, and cost needed for operation. While promising results occurred in the removal of arsenic and total hardness, this project was unable to obtain consistent results and final water samples with pH values between the recommended standard of 6.5 to 8. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection