Master of Science / Geology / Saugata Datta / The province (upazila) of Matlab in SE Bangladesh is highly affected with elevated concentrations of dissolved As content and widespread fecal contamination in untreated drinking waters. The study area is sedimentologically composed of thick floodplain deposits of Holocene age overlying Plio-Pleistocene grey fine to coarse sands with considerable clays (consisting of Dupi Tila formation). The goal of the current study is to understand the possible impact of co-occurrence of dissolved organic carbon (along with As release) and fecal indicator bacteria (e.g., E.coli) in aquifers from shallow to deep groundwater quality in this area. Nineteen groundwater (spanning a depth range of 14 to 240 m) samples and nine surface water samples (eight ponds and one canal in proximity to the piezometer nests) were collected from four different piezometric nests within north and south Matlab Upazila in Bangladesh during the monsoonal season (Jun-Jul 2014). The analyses of dissolved organic carbon (DOC) and its fluorescence properties indicate that the chemical character of DOC from shallow to intermediate groundwaters (<150 m) and surface water is dominated by more aromatic and humic materials than deeper groundwaters. Both groundwaters and surface waters may receive humic substances leached from soil and/or from the cellular constituents and exudates of indigenous aquatic organisms. Dissolved organic carbons in groundwater and surface waters are composed of predominantly UVA and UVC-humic like along with tryptophan like components. Only 15% of total C is modern carbon at shallowest depths (<30 m) in groundwaters. The recharge source of groundwaters is from local precipitation, with or without some evaporation before infiltration as depicted by the δ2H and δ¹⁸O variations and the water is infiltrating through mostly terrestrially derived weathered sediments into the aquifers. The type of water in the study area is Ca-Na-HCO₃⁻ type. More toxic and soluble As (III) is present in shallow groundwaters (<30 m). High concentrations of As (V) and As[subscript (t)] are observed high in shallow and intermediate depth wells (<150 m). The most probable number based on the Colilert test and qPCR result for E.coli suggest that unprotected surface waters are harbingers for high microbial population compared to hand pumped wells. However, the very low observed concentrations of cultured E. coli (<1-10 MPN/100 mL) and E. coli DNA (<40 Copies/100 mL) in the wells indicates that the abundance of E.coli cells decrease rapidly with residence time in oligotrophic aquifers. Thus, it may be suggested that more humic DOC in shallow and intermediate groundwaters may be involved in complexation or other biogeochemical reactions that may mobilize As in groundwater. The non-indigenous bacteria can be the primary producers of DOC in the aquifers which can be utilizing surface derived DOC.

Agricultural runoff can carry FIB that can pollute surface waters through the soil matrix. This study was designed to inspect the impact of temperature and matrix on the survival of FIB. The FIB were routinely enumerated over an 18-day period from fecal samples and freshwater microcosms maintained at 4oC, 22oC, and 35oC. It was found that the FIB studied underwent a primary growth of up to 1-log10 to 3-log10, highlighting the weakness of conventional FIB as indicators of pathogen contamination. The concentrations of FIB in the water phase were found to be significantly greater than those observed in the fecal phase in all FIB and their associated survivals were found to be significantly different too. Similarly, temperature was also found to be a significant factor for the survival of FIB. While the differences in the survival were significant, there was a slight variation in the patterns regarding the differences.

<p>Greywater is domestic household wastewater without inputfrom the toilet, i.e. wastewater from sinks, the shower,washing machine and dishwasher in a home. Source separation ofgreywater can be a strategy to enhance recirculation of plantnutrients and/or improve water use. The risk for transmissionof disease when reusing greywater is largely dependent on thecross-contamination by faeces. High levels of faecalindicators, mainly thermotolerant coliform bacteria, have beenreported in greywater, indicating substantial faecal pollution.However, growth of indicator bacteria within the system leadsto an overestimation of thefaecal input and thus the hygienerisk. The faecal input of the greywater in Vibyåsen,Sollentuna, North of Stockholm, was estimated to be 0.04 ±0.02 g faeces person-1 day-1 from the quantification of thefaecal sterol coprostanol, compared to 65 g, 5.2 g and 0.22 gp-1 d-1 using E. coli, enterococci and cholesterolrespectively.</p><p>Prevalence of pathogens in the population and the faecalload based on coprostanol concentrations were used to form thebasis of a screening-level quantitative microbial riskassessment (QMRA) that was undertaken for rotavirus, Salmonellatyphimurium, Campylobacter jejuni, Giardia intestinalis andCryptosporidium parvum, looking at the treatment required to bebelow an acceptable level of risk (10-3) for reuse or dischargeof the greywater. The different exposure scenarios simulated–groundwater recharge, direct contact, irrigation andrecreational water–showed that a reduction of 0.7–3.7 log was needed for rotavirus, with the measured level offaecal load in Vibyåsen. The other pathogen of concern wasCampylobacter, where a 2.2 log reduction was needed forgroundwater recharge. The infectious dose of Salmonella is highand the excretion numbers of Giardia cysts and Cryptosporidiumoocysts low, resulting in no treatment requirements for theseorganisms under these circumstances. Pathogen input fromcontaminated food via the kitchen sink had a minor effect onthe microbiological quality of the greywater. Studies on virusoccurrence in greywater as well as validation of the faecalload of greywater at another site would give valuable input forfuture QMRAs.</p><p>Greywater treatment efficiency studies, especially on virusremoval, are scarce and more investigations are warranted.Active sludge may not be a suitable technique for greywater dueto the low carbon content in this flow. Chemical precipitationhas the advantage of removing phosphorus as well as virusesefficiently and it is suggested as one possible method fortreating greywater. Otherwise the most common practice forgreywater treatment in Sweden is soil infiltration. However, itis suggested that the recommendations for wastewaterinfiltration also be observed for greywater, despite the lowfaecal load, due to the simulated results on virus reductionneeded.</p><p><b>Key words:</b>greywater, greywater reuse, greywatertreatment, microbial risk assessment, groundwater recharge,irrigation, recreational water, faecal contamination, indicatorbacteria, index organisms, faecal sterols, bacteriophages,enteric pathogens, rotavirus, Salmonella, Campylobacter,Giardia, Cryptosporidium, Legionella</p>

Climatic variations, together with large-scale environmental forces and human development affect the quality of coastal recreational waters, creating potential risks to human health. These environmental forces, including increased temperature and precipitation, often promote specific vector-borne diseases in the Caribbean and Gulf of Mexico. Human activities affect water quality through discharges from urban areas, including nutrient and other pollutants derived from wastewater systems. Both water quality of recreational beaches and vector-borne diseases can be better managed by understanding their relationship with local environmental forces. I evaluated how changes in vector-borne diseases and poor recreational water quality were related to specific environmental factors through the application of satellite-derived observations, field observations, and public health records. Variability in dengue fever incidence rates in coastal towns of the Yucatan Peninsula (Mexico) was evaluated with respect to environmental factors in Chapter Two. Correlations between fecal indicator bacteria concentrations (i.e., culturable enterococci) at Escambron Beach (San Juan, Puerto Rico, USA) and regional environmental factors are discussed in Chapter Three. Predictions of dengue fever occurrences in the Yucatan Peninsula were tested using a nonlinear approach (i.e., Artificial Neural Networks) and are presented in Chapter Four. The Artificial Neural Network (ANN) model was also used to predict culturable enterococci concentration exceeding safe recreational water quality standards in Escambron Beach and results are presented in Chapter Five. Environmental factors assessed to understand their influence on dengue fever occurrences and culturable enterococci concentrations included precipitation, mean sea level (MSL), air temperatures (e.g., maximum, minimum, and average), humidity, and satellite-derived sea surface temperature (SST), dew point, direct normal irradiance (DNI), and turbidity. These factors were combined with demographic data (e.g., population size) and compared with dengue fever incidence rates and culturable enterococci concentration using linear and nonlinear statistical approaches. Dengue incidence rates in Yucatan (Mexico) generally increased in July/August and decreased during November/December. A linear regression model showed that previous dengue incidence rates explained 89% of dengue fever variability (p < 0.05). Dengue incidence two weeks prior (previous incidence) influences future outbreaks by allowing the virus to continue propagating. Yet dengue incidence was best explained by precipitation, minimum air temperature, humidity, and SST (p < 0.05). Dengue incidence variability was best explained by SST and minimum air temperature in our study region (r = 0.50 and 0.48, respectively). Increases in SST preceded increased dengue incidence rate by eight weeks. Dengue incidence time series were positively correlated to SST and minimum air temperature anomalies. This is related to the virus and mosquito behavior. Including oceanographic variables among environmental factors in the model improved modelling skill of dengue fever in Mexico. Chapter Three shows that precipitation, MSL, DNI, SST, and turbidity explained some of the enterococci variation in Escambron Beach surface waters (AIC = 26.76; r = 0.20). Variation in these parameters preceded increased culturable enterococci concentrations, with lags spanning from 24 h up to 11 days. The highest influence on culturable enterococci was precipitation between 480 mm–900 mm. Rainy events often result in overflows of sewage systems and other non-point sources near Escambron Beach in Puerto Rico. A significant decrease in culturable enterococci concentrations was observed during increased irradiance (r = -0.24). This may be due to bacterial inactivation. Increased culturable enterococci concentrations were significantly associated with higher turbidity daily anomalies (r = 0.25), in part because bacteria were protected from light inactivation. Increased culturable enterococci concentrations were related to warmer SST anomalies (r = 0.12); this is likely due to increased bacterial activity and reproduction. Higher culturable enterococci concentrations were also significantly correlated to medium to high values of dew point daily anomalies (r = 0.19). A significant decrease in culturable enterococci during higher daily MSL anomalies (r = -0.19) is possibly due to dilution of bacteria in beach waters, whereas during lower MSL anomalies the back-washing promotes increased bacteria concentrations through mixing from sediments. These environmental variables improve our understanding of the ecology of these bacteria over time. The predictive capability increases by including more than one environmental variable. Chapter Four explains a predictive model of dengue fever occurrences in San Juan, Puerto Rico (1994–2012), and Yucatan (2007–2012). The model was modified to predict dengue fever outbreak occurrences for two population segments: population at risk of infection (i.e., < 24 years old) and vulnerable population (i.e., < 5 years old and > 65 years old). There were a total of four predictive models, two sets for each location using the specified population segments. Model predictions showed previous dengue cases, minimum air temperature, date, and population size as the factors with the most influence to predict dengue fever outbreak occurrences in Mexico. Previous dengue cases, maximum air temperature, date, and population size were the most influential factors for San Juan, Puerto Rico. The models showed an accuracy around 50% and a predictive capability of 70%. These environmental and demographic variables are important primary predictors for dengue fever outbreaks in Puerto Rico and Mexico. Chapter Five shows the application of the ANNs model to predict culturable enterococci exceedance based on the U.S. Environmental Protection Agency (U.S. EPA) Recreational Water Quality Criteria (RWQC) at Escambron Beach, San Juan, Puerto Rico. The model identified DNI, turbidity, 48 h cumulative precipitation, MSL, and SST as the most influential factors to predict enterococci concentration exceedance, based on the U.S. EPA RWQC at Escambron Beach from 2005–2014. The model showed an accuracy of 76%, with a predictive capability greater than 60%, which is higher than linear models. Results showed the applicability of remote sensing data and ANNs to predict recreational water quality and help improve early warning system and public health. This work helps to better understand complex relationships between climatic variations and public health issues in tropical coastal areas and provides information that can be used by public health practitioners.

Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment. Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine sinceE. colihad a rapid inactivation in the urine and faecalstreptococci were found to grow within the system. The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.SalmonellaandE. coli) were rapidly inactivated (time for 90%reduction, T90&lt;5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T90of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,rhesusrotavirus andSalmonella typhimuriumphage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT90-values were 35 and 71 days, respectively.Cryptosporidiumoocysts were less persistent with a T90of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia. By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be&lt;10-3for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10-4. By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture. <b>Keywords:</b>urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.

<p>Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment.</p><p>Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine since<i>E. coli</i>had a rapid inactivation in the urine and faecalstreptococci were found to grow within the system.</p><p>The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.<i>Salmonella</i>and<i>E. coli</i>) were rapidly inactivated (time for 90%reduction, T₉₀<5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T₉₀of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,<i>rhesus</i>rotavirus and<i>Salmonella typhimurium</i>phage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT₉₀-values were 35 and 71 days, respectively.<i>Cryptosporidium</i>oocysts were less persistent with a T₉₀of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia.</p><p>By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be<10^-3for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10^-4.</p><p>By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture.</p><p><b>Keywords:</b>urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.</p>

Dans de nombreux pays en développement, la qualité médiocre de l'eau constitue une menace majeure pour la santé humaine. Par ailleurs, le manque d'accès à l'eau potable et à l'assainissement sont un frein majeur au développement. La Fleuve Rouge est le deuxième plus grand fleuve au Vietnam et constitue la principale source d'eau pour la population du Nord-Vietnam. Cette thèse présente les résultats des observations et de la modélisation des bactéries indicatrices de la contamination fécales (BICF) et du carbone organique (CO) dans la Fleuve Rouge. Le modèle Seneque/RIVERSTRAHLER utilisant l’ensemble des données recueillies a permis d'étudier la dynamique et la répartition saisonnière des BICF et du CO dans la Fleuve Rouge et ses affluents. Un scénario, basé sur l’évolution démographique et les changements d’usage des terres prévus à l'horizon 2050, a montré une augmentation limitée des nombres des BICF par rapport à la situation actuelle. Ceci est particulièrement le cas pour la ville d’Hanoi même si la population devrait tripler d'ici 2050. Les apports en CO et la respiration hétérotrophe résultant du CO abouti à un système qui est une forte source en CO2 pour l’atmosphère. Les résultats du modèle reflètent également l'importance des différents usages des terres, le débit et la prédominance des sources diffuses relatifs aux sources ponctuelles sur les BIFC et CO dans le Fleuve Rouge. Cette thèse fournit de nouvelles informations sur les teneurs en BICF et CO dans la Fleuve Rouge ainsi qu’une base de discussion pour les décideurs sur la gestion future des eaux usées rejetés dans ce Fleuve. / In many developing countries, poor water quality poses a major threat to human health and the lack of access to clean drinking water and adequate sanitation continues is a major brake on development. The Red River is the second largest river in Vietnam and constitutes the main water source for the population of North Vietnam. This thesis presents the results from observations and modeling of both faecal indicator bacteria (FIB) and organic carbon (OC) in the Red River system, North Vietnam. The objective of this work was to measure FIB numbers and OC concentrations in this system and then to model these parameters in order to investigate scenarios for 2050 when population in the area is estimated to have doubled. The dataset was then modeled using the Seneque/Riverstrahler model in order to investigate the dynamics and seasonal distribution of FIB and OC in the Red River and its upstream tributaries. A scenario, based on the predicted changes in future demographics and land use in the Red River system for the 2050 horizon, showed only a limited increase of FIB numbers compared with the present situation. This was particularly the case in Hanoi even though the population is expected to triple by 2050. The OC inputs and the resulting heterotrophic respiration of this OC resulted in a system that was a strong CO2 source. The model results also reflected the importance of land use, discharge and the dominance of non-point sources over point sources for FIB and OC in the Red River. This thesis provides some new information on FIB in the Red River as well as providing a base for discussion with decision makers on the future management of wastewater in the Red River.

Greywater is domestic household wastewater without inputfrom the toilet, i.e. wastewater from sinks, the shower,washing machine and dishwasher in a home. Source separation ofgreywater can be a strategy to enhance recirculation of plantnutrients and/or improve water use. The risk for transmissionof disease when reusing greywater is largely dependent on thecross-contamination by faeces. High levels of faecalindicators, mainly thermotolerant coliform bacteria, have beenreported in greywater, indicating substantial faecal pollution.However, growth of indicator bacteria within the system leadsto an overestimation of thefaecal input and thus the hygienerisk. The faecal input of the greywater in Vibyåsen,Sollentuna, North of Stockholm, was estimated to be 0.04 ±0.02 g faeces person-1 day-1 from the quantification of thefaecal sterol coprostanol, compared to 65 g, 5.2 g and 0.22 gp-1 d-1 using E. coli, enterococci and cholesterolrespectively. Prevalence of pathogens in the population and the faecalload based on coprostanol concentrations were used to form thebasis of a screening-level quantitative microbial riskassessment (QMRA) that was undertaken for rotavirus, Salmonellatyphimurium, Campylobacter jejuni, Giardia intestinalis andCryptosporidium parvum, looking at the treatment required to bebelow an acceptable level of risk (10-3) for reuse or dischargeof the greywater. The different exposure scenarios simulated–groundwater recharge, direct contact, irrigation andrecreational water–showed that a reduction of 0.7–3.7 log was needed for rotavirus, with the measured level offaecal load in Vibyåsen. The other pathogen of concern wasCampylobacter, where a 2.2 log reduction was needed forgroundwater recharge. The infectious dose of Salmonella is highand the excretion numbers of Giardia cysts and Cryptosporidiumoocysts low, resulting in no treatment requirements for theseorganisms under these circumstances. Pathogen input fromcontaminated food via the kitchen sink had a minor effect onthe microbiological quality of the greywater. Studies on virusoccurrence in greywater as well as validation of the faecalload of greywater at another site would give valuable input forfuture QMRAs. Greywater treatment efficiency studies, especially on virusremoval, are scarce and more investigations are warranted.Active sludge may not be a suitable technique for greywater dueto the low carbon content in this flow. Chemical precipitationhas the advantage of removing phosphorus as well as virusesefficiently and it is suggested as one possible method fortreating greywater. Otherwise the most common practice forgreywater treatment in Sweden is soil infiltration. However, itis suggested that the recommendations for wastewaterinfiltration also be observed for greywater, despite the lowfaecal load, due to the simulated results on virus reductionneeded. <b>Key words:</b>greywater, greywater reuse, greywatertreatment, microbial risk assessment, groundwater recharge,irrigation, recreational water, faecal contamination, indicatorbacteria, index organisms, faecal sterols, bacteriophages,enteric pathogens, rotavirus, Salmonella, Campylobacter,Giardia, Cryptosporidium, Legionella / NR 20140805

Urban stormwater runoff is both an environmental threat and a valuable water resource. This dissertation explores the use of two stormwater management strategies, namely green stormwater infrastructure and stormwater real-time control (RTC), for capturing and treating urban stormwater runoff. Chapter 2 focuses on clean bed filtration theory and its application to fecal indicator bacteria removal in experimental laboratory-scale biofilters. This analysis is a significant step forward in our understanding of how physicochemical theories can be melded with hydrology, engineering design, and ecology to improve the water quality benefits of green infrastructure. Chapter 3 focuses on the novel application of unsteady transit time distribution (TTD) theory to solute transport in a field-scale biofilter. TTD theory closely reproduces experimental bromide breakthrough concentrations, provided that lateral exchange with the surrounding soil is accounted for. TTD theory also provides insight into how changing distributions of water age in biofilter storage and outflow affect key stormwater management endpoints, such as biofilter pollutant treatment credit. Chapter 4 focuses on stormwater RTC and its potential for improving runoff capture and water supply in areas with Mediterranean climates. We find that the addition of RTC increases the percent of runoff captured, but does not increase the percent of water demand satisfied. Our results suggest that stormwater RTC systems need to be implemented in conjunction with context-specific solutions (such as spreading basins for groundwater recharge) to reliably augment urban water supply in areas with uneven precipitation. Through a combination of modeling and experimental studies at a range of scales, this dissertation lays the foundation for future integration of TTD theory with RTC to improve regional stormwater management. / Doctor of Philosophy / Urban stormwater runoff contains a variety of pollutants. Conventional storm drain systems are designed to move stormwater as quickly as possible away from cities, delivering polluted runoff to local streams, rivers, and the coastal ocean – and discarding a valuable freshwater resource. By contrast, green stormwater infrastructure captures and retains stormwater as close as possible to where the rain falls. Green stormwater infrastructure can also help remove pollutants from stormwater through physical, chemical, and biological treatment processes. This dissertation describes two modeling approaches for understanding and predicting pollutant removal processes in green stormwater infrastructure (Chapters 2 and 3). Chapter 4 explores the implementation of smart stormwater systems, which use automated controllers and sensors to adaptively address stormwater management challenges. Through a combination of modeling and experimental studies at a range of scales, this dissertation lays the foundation for future improvements to regional stormwater management.

No description available.