Many types of contaminants of emerging concern (CECs), including per- and poly-fluoroalkyl substances (PFAS), have been found in leachate of operating municipal landfills. However, information on CECs in leachate of historic landfills (≥3 decades since closure, often lacking engineered liners or leachate collection systems) and the related risk posed from groundwater plumes discharging to nearby aquatic ecosystems is limited. In this study, 48 samples of leachate-impacted groundwater were collected from 20 historic landfills in Ontario, Canada. The CECs measured included artificial sweeteners (ASs), PFAS, organophosphate esters (OPE), pharmaceuticals, bisphenols, sulfamic acid, perchlorate, and substituted phenols. Several landfills, including ones closed in the 1960s, had total PFAS concentrations similar to those previously measured at modern landfills, with a maximum observed here of 12.7 μg/L. Notably elevated concentrations of several OPE, cotinine, and bisphenols A and S were found at many 30-60 year-old landfills. There was little indication of declining concentrations with landfill age, suggesting historic landfills can be long-term sources of CECs to groundwater. A full-year field study was performed on a 0.5-km reach of an urban stream receiving contaminated groundwater from nearby historic landfills. Elevated concentrations of ammonium, the AS saccharin, an indicator of old landfill leachate, and CECs (e.g., maximum total PFAS of 31 μg/L) in the shallow discharging groundwater were relatively stable across the seasons but were spatially restricted by hyporheic exchange and discharge of other groundwater. This indicates a patchy but long-term exposure for endobenthic organisms, which are rarely monitored. Stream water concentrations were more dilute, but increased markedly across the landfill stretch, and showed signs of increases in winter and after rain/snowmelt events. These findings provide guidance on which CECs may require monitoring at historic landfill sites and suggest how landfill monitoring programs could be improved to fully capture the risk to receiving water bodies. / Thesis / Master of Science (MSc) / Historic landfills are a known source of groundwater contamination. This study investigated whether these landfills contain new groups of chemicals, called contaminants of emerging concern (CECs), which are suspected to pose serious environmental and human health risks. This study found many CECs at high concentrations in most of the 20 historic landfill sites investigated, even those closed up to 60 years. A full-year investigation at one historic landfill site showed that organisms living in the sediments of a nearby stream are exposed to high concentrations all year long. Concentrations in the stream increased as it flowed past the landfill, and may be higher in winter and after rains, times monitoring is rarely done. The elevated concentrations of harmful contaminants in this water are potentially threatening the stream ecosystem. Operators of historic sites should consider testing for CECs and ensure that monitoring strategies accurately evaluate the risk posed to the environment.

No description available.

abstract: Population growth and fresh water depletion challenge drinking water utilities. Surface water quality is impacted significantly by climate variability, human activities, and extreme events like natural disasters. Dissolved organic carbon (DOC) is an important water quality index and the precursor of disinfection by-products (DBPs) that varies with both hydrologic and anthropogenic factors. Granular activated carbon (GAC) is a best available technology for utilities to meet Stage 2 D/DBP rule compliance and to remove contaminants of emerging concern (CECs) (e.g., pharmaceutical, personal care products (PCPs), etc.). Utilities can operate GAC with more efficient and flexible strategies with the understanding of organic occurrence in source water and a model capable predicting DOC occurrence. In this dissertation, it was found that DOC loading significantly correlated with spring runoff and was intensified by dry-duration antecedent to first flush. Dynamic modeling based on reservoir management (e.g., pump-back operation) was established to simulate the DOC transport in the reservoir system. Additionally, summer water recreational activities were found to raise the level of PCPs, especially skin-applied products, in raw waters. GAC was examined in this dissertation for both carbonaceous and emerging nitrogenous DBP (N-DBP) precursors (i.e., dissolved organic nitrogen (DON)) removal. Based on the experimental findings, GAC preferentially removes UV254-absorbing material, and DOC is preferentially removed over DON which may be composed primarily of hydrophilic organic and results in the low affinity for adsorption by GAC. The presence of organic nitrogen can elevate the toxicity of DBPs by forming N-DBPs, and this could be a major drawback for facilities considering installation of a GAC adsorber owing to the poor removal efficiency of DON by GAC. A modeling approach was established for predicting DOC and DON breakthrough during GAC operation. However, installation of GAC adsorber is a burden for utilities with respect to operational and maintenance cost. It is common for utilities to regenerate saturated GAC in order to save the cost of purchasing fresh GAC. The traditional thermal regeneration technology for saturated GAC is an energy intensive process requiring high temperature of incineration. Additionally, small water treatment sites usually ship saturated GAC to specialized facilities for regeneration increasing the already significant carbon footprint of thermal regeneration. An innovative GAC regeneration technique was investigated in this dissertation for the feasibility as on-site water treatment process. Virgin GAC was first saturated by organic contaminant then regenerated in-situ by iron oxide nanocatalysts mixed with hydrogen peroxide. At least 70 % of adsorption capacity of GAC can be regenerated repeatedly for experiments using modeling compound (phenol) or natural organic matter (Suwannee River humic acid). The regeneration efficiency increases with increasing adsorbate concentration. Used-iron nanocatalysts can be recovered repeatedly without significant loss of catalytic ability. This in-situ regeneration technique provides cost and energy efficient solution for water utilities considering GAC installation. Overall, patterns were found for DOC and CEC variations in drinking water sources. Increasing concentrations of bulk (DOC and DON) and/or trace organics challenge GAC operation in utilities that have limited numbers of bed-volume treated before regeneration is required. In-situ regeneration using iron nanocatalysts and hydrogen peroxide provides utilities an alternative energy-efficient operation mode when considering installation of GAC adsorber. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2012

No description available.

Pharmaceuticals are an important class of pollutants in aquatic ecosystems. Detected concentration are typically in the range 1 ng/L – 1 μg/L. Traditional wastewater treatment does not provide a complete removal of these contaminants; hence, they may have a negative impact on the environment. In addition, microalgae are an ecologically-meaningful target group of species for bioindication purposes as well as primary production and oxygen supply. The present work aimed to investigate the effect of Ibuprofen on the green alga Pseudokirchneriella subcapitata. Algal cultures were exposed to five different concentrations of the drug (5, 15, 45, 135, 405 mg/L) for four days. Absorbance measured at 680 nm was determined every day and obtained data were transformed into cell concentration (cells/mL) by a previously prepared calibration curve. Specific growth rate, generation time, percent inhibition and effective concentration were calculated. Moreover, one way ANOVA with Tukey’s test were applied to observe differences between groups and time periods. Based on this study, all the cultures treated with Ibuprofen had a growth inhibition as well as presenting a lag phase. Increasing the Non-Steroidal Anti-Inflammatory drug (NSAID) concentration reduced the growth rate and consequently, increased the percent inhibition in a concentration-dependent manner. According to this report, new research should be focused on the development of hybrid systems for degradation and removal of pharmaceuticals. NSAID pollution may lead to a reduction in the diversity and number of functional groups of eukaryotic algae. Finally, more research should be devoted to the toxicity of drugs in a variety of test organisms and development of reliable methods for toxicity test at low and chronic exposures to achieve more realistic conclusions.

No description available.

abstract: Many manmade chemicals used in consumer products are ultimately washed down the drain and are collected in municipal sewers. Efficient chemical monitoring at wastewater treatment (WWT) plants thus may provide up-to-date information on chemical usage rates for epidemiological assessments. The objective of the present study was to extrapolate this concept, termed 'sewage epidemiology', to include municipal sewage sludge (MSS) in identifying and prioritizing contaminants of emerging concern (CECs). To test this the following specific aims were defined: i) to screen and identify CECs in nationally representative samples of MSS and to provide nationwide inventories of CECs in U.S. MSS; ii) to investigate the fate and persistence in MSS-amended soils, of sludge-borne hydrophobic CECs; and iii) to develop an analytical tool relying on contaminant levels in MSS as an indicator for identifying and prioritizing hydrophobic CECs. Chemicals that are primarily discharged to the sewage systems (alkylphenol surfactants) and widespread persistent organohalogen pollutants (perfluorochemicals and brominated flame retardants) were analyzed in nationally representative MSS samples. A meta-analysis showed that CECs contribute about 0.04-0.15% to the total dry mass of MSS, a mass equivalent of 2,700-7,900 metric tonnes of chemicals annually. An analysis of archived mesocoms from a sludge weathering study showed that 64 CECs persisted in MSS/soil mixtures over the course of the experiment, with half-lives ranging between 224 and >990 days; these results suggest an inherent persistence of CECs that accumulate in MSS. A comparison of the spectrum of chemicals (n=52) analyzed in nationally representative biological specimens from humans and MSS revealed 70% overlap. This observed co-occurrence of contaminants in both matrices suggests that MSS may serve as an indicator for ongoing human exposures and body burdens of pollutants in humans. In conclusion, I posit that this novel approach in sewage epidemiology may serve to pre-screen and prioritize the several thousands of known or suspected CECs to identify those that are most prone to pose a risk to human health and the environment. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2013

Contaminants of emerging concern (CECs) are continuously being released into the environment mainly because of their incomplete removal in the sewage treatment plants (STPs). The CECs selected for the study include antibiotics (macrolides, sulfonamides and ciprofloxacin), sucralose (an artificial sweetener) and dioctyl sulfosuccinate (DOSS, chemical dispersant used in the Deepwater Horizon oil spill). After being discharged into waterways from STPs, photo degradation is a key factor in dictating the environmental fate of antibiotics and sucralose. Photodegradation efficiency depends on many factors such as pH of the matrix, matrix composition, light source and structure of the molecule. These factors exert either synergistic or antagonistic effects in the environment and thus experiments with isolated factors may not yield the same results as the natural environmental processes. Hence in the current study photodegradation of 13 CECs (antibiotics, sucralose and dicotyl sulfosuccinate) were evaluated using natural water matrices with varying composition (deionized water, fresh water and salt water) as well as radiation of different wavelengths (254 nm, 350 nm and simulated solar radiation) in order to mimic natural processes. As expected the contribution of each factor on the overall rate of photodegradation is contaminant specific, for example under similar conditions, the rate in natural waters compared to pure water was enhanced for antibiotics (2-11 fold), significantly reduced for sucralose (no degradation seen in natural waters) and similar in both media for DOSS. In general, it was observed that the studied compounds degraded faster at 254 nm, while when using a simulated sunlight radiation the rate of photolysis of DOSS increased and the rates for antibiotics decreased in comparison to the 350 nm radiation. The photo stability of the studied CECs followed the order sucralose > DOSS > macrolides > sulfonamides > ciprofloxacin and a positive relationship was observed between photo stability and their ubiquitous presence in natural aquatic matrices. An online LC-MS/MS method was developed and validated for sucralose and further applied to reclaimed waters (n =56) and drinking waters (n = 43) from South Florida. Sucralose was detected in reclaimed waters with concentrations reaching up to 18 µg/L. High frequency of detection (> 80%) in drinking waters indicate contamination of ground waters in South Florida by anthropogenic activity.

Indirect potable reuse has been practiced with the potential to enhance sustainability of water resources if planned accordingly. Depending on the pretreatment implemented for potable reuse, emerging contaminants; such as pharmaceuticals, personal care products, industrial solvents, bacterial/viral pathogens, and disinfection byproducts, might be present in source water and difficult to remove via various water treatment technologies. Low molecular weight organic compounds are especially challenging to remove and may require treatment optimization. The overarching purpose of this study was to demonstrate the feasibility of a carbon-based advanced treatment train; including ozonation, biological activated carbon (BAC) filtration and granular activated carbon (GAC) adsorption to achieve water quality suitable for potable reuse and assess the impact of a range of operating conditions for emerging contaminant removal at pilot-scale. The results from this study showed that carbon-based treatment train is equally effective as more commonly used, and more costly, membrane-based treatment trains in terms of pathogen and disinfection byproduct removal. A multiple-barrier approach was implemented, with each treatment stage capable of removing total organic carbon (TOC). GAC was responsible for removal of most of the TOC and emerging contaminants and this removal depended on the number of bed volumes of water processed by GAC. Empty bed contact time was another factor that dictated the extent of TOC removal in the BAC and GAC units as the carbon media was exhausted. Among the emerging contaminants detected, sucralose, iohexol and acesulfame-k were present in the highest concentrations in the influent and were detected consistently in the GAC effluent, thus making them good indicators of treatment performance. Apart from organics removal, BAC played an important role in removal of nutrients, such as ammonia via nitrification. N-Nitrosodimethlyamine (NDMA) was formed in the treatment process by ozone, but was shown to be effectively removed by BAC. EBCT, temperature, ozone dose and presence of pre-oxidants, such as monochloramine, played an important role in determining the amount of NDMA removed. These factors can be further optimized to improve NDMA removal. Sodium bisulfite was used for dechlorinating monochloramine residual post ozone. Nitrification in the BAC was shown to be inhibited by excess of sodium bisulfite dose. Thus monochloramine residual needs to be dechlorinated with sodium bisulfite to help with NDMA degradation but at the same time the sodium bisulfite dose needs to be monitored to allow complete nitrification in the BAC. 1,4-dioxane, another contaminant of emerging concern, was monitored in the treatment process. Biodegradation of 1,4-dioxane was enhanced via addition of tetrahydrofuran as a growth substrate. Biodegradation of 1,4-dioxane can help reduce energy and capital costs associated with advanced oxidation processes that are currently used for 1,4-dioxane removal. Further, relying on biodegradation for the removal of 1,4-dioxane can help avoid the formation of disinfection byproducts associated with advanced oxidation processes such as ozone with peroxide or ultraviolet disinfection with peroxide. The results from this project can be useful for designing potable reuse treatment trains and provide a baseline for removal of organic carbon and emerging contaminants. The conventionally used reverse osmosis and ultrafiltration approach is useful for organics removal in areas where the rationale behind potable reuse is water scarcity. Operational difficulties encountered during this study can prove to be important as this treatment process is scaled up to treat a total of 120 MGD of water for managed aquifer recharge. Overall the lessons learnt from this study can give a better understanding of a carbon-based treatment and further the advancement of reuse projects that have drivers other than water scarcity. / Doctor of Philosophy / The increased growth in urban areas has been accompanied by an increase in potable water demand, leading to depletion of surface and groundwater. Further, the discharge of nutrients such as nitrogen and phosphorus into some of these water bodies can lead to algal blooms. Water reuse involves treating used water and discharging into either a surface or groundwater body. Water reuse has been sought after as a solution to prevent these nutrients being discharged into surface water and to provide a sustainable solution for depletion of water sources. Direct or indirect potable reuse can include a combination of advanced treatment methods such as membrane filtration using ultrafiltration and reverse osmosis, biological filtration, granular or powdered activated carbon adsorption and disinfection methods such as ozonation and ultraviolet disinfection. This study focused on Hampton Roads Sanitation District's managed aquifer recharge project 'sustainable water initiative for tomorrow' (SWIFT), two different advanced water treatment strategies, namely carbon-based and membrane-based were implemented on a pilot-scale (20,000 L/day). The driver for indirect potable reuse in this study was not related to water shortage but aimed at reducing the nutrients discharged into the Chesapeake Bay. Other reasons for implementing reuse included recharging the depleting groundwater levels, land subsidence, and preventing flooding and seawater intrusion near the coastal areas. Membrane-based treatments, such as reverse osmosis, have been well established and studied for potable reuse. The less frequently used carbon-based treatment, that includes used of activated carbon for adsorption and biodegradation of organics (not involving any membrane barrier), was shown to be cost-effective and provided equal protection as that of the membrane-based system in terms of removal of pathogens. Further, since there is no membrane involved in the carbon-based treatment the energy requirements are less than that of the membrane-based treatment and concentrated brine solution is not produced, which makes it favorable for potable reuse where water scarcity is not an issue. This carbon-based treatment which included ozonation and activated carbon filtration and adsorption was further monitored and optimized for removal of organic contaminants and disinfection byproducts. Emerging contaminants such as pharmaceuticals, industrial solvents and personal care products can be harmful to human health and water ecology even at low concentrations. These contaminants are often present in wastewater effluent and can enter drinking water sources if untreated. These emerging contaminants were shown to be effectively removed by ozonation and granular activated carbon adsorption. The formation of disinfection byproducts such as N-nitrosodimethylamine in the treatment process and its removal in the biological activated carbon filtration was also monitored. The impact of temperature, presence of pre-oxidants and design factors such as ozone dose and empty bed contact time affected the removal of all these contaminants. This study provided an understanding of implementing carbon-based treatment for managed aquifer recharge for optimizing removal of bulk organic carbon and emerging contaminants. The results from this study can be utilized for designing advanced water treatment systems and can prove to be a guideline for monitoring and removing emerging contaminants.

Les tensioactifs poly- et perfluoroalkylés (PFAS) sont des composés d’origine anthropique produits à partir des années 1950 et qui sont désormais considérés comme des polluants ubiquistes. La première partie de ce travail a consisté à optimiser et valider des procédures pour l’analyse ultra-trace des PFAS. Ces méthodes ont ensuite été utilisées afin d’apporter de nouveaux éléments de réponse sur l’occurrence et la dynamique des PFAS dans les environnements aquatiques. Une attention particulière a été accordée aux valeurs censurées (<LD). Dans les eaux de surface et les sédiments, à l’échelle nationale, le perfluorooctane sulfonate (PFOS) s’est avéré prédominant parmi les acides perfluoroalkylés (PFAA) considérés ; la fraction organique du sédiment est apparue un facteur de contrôle clé des teneurs sédimentaires. L’utilisation des cartes auto-organisatrices de Kohonen a facilité la synthèse des résultats et les comparaisons entre sites. A une échelle plus locale, ces travaux ont permis de cartographier la contamination sédimentaire d’un estuaire macrotidal et d’étudier les facteurs de contrôle de leur distribution. La dynamique spatio-temporelle des PFAS et leur transfert aux premiers maillons trophiques ont été évalués en milieu fluvial urbain (la Seine) et en milieu estuarien (la Gironde). La détermination des facteurs d’amplification trophique en estuaire de Gironde confirme le caractère bioamplifiable du PFOS et de certains PFAA à longue chaîne. Le dernier axe de ces travaux concernait la recherche de PFAS d’intérêt émergent zwittérioniques et cationiques ; des résultats préliminaires semblent dissiper les inquiétudes concernant leur potentiel de bioaccumulation. / Poly- and perfluoroalkyl surfactants (PFAS) are anthropogenic compounds that have been used sincethe 1950s in a variety of applications and that have emerged as ubiquitously distributed contaminants.The first aim of this work was to optimize and validate analytical procedures for the trace-leveldetermination of PFAS. These methods were then applied to various sets of environmental samples,providing new elements to document the occurrence and environmental fate of PFAS in aquaticecosystems. In terms of statistical analyses, a special care has been devoted to incorporate nondetects(data <LOD). In French surface waters and sediments, perfluorooctane sulfonate (PFOS) wasthe prevailing perfluoroalkylated acid (PFAA); sediment organic carbon fraction was a key controllingfactor of PFAS sedimentary levels. Kohonen self-organizing maps were used to highlight similaritiesand differences between sites, providing evidence for distinctive features, sometimes at watershedscale. A mapping of PFAS in sediments was established in a macrotidal estuary, along with theirpartitioning behavior in the water column. The spatio-temporal dynamics of PFAS and transfer to thefirst trophic levels were investigated in an urban freshwater hydrosystem (the Seine River) and in anestuarine environment (Gironde estuary). In the Gironde estuary, trophic magnification factors (TMF)were significantly >1 for PFOS and several long-chain PFAA, providing new evidence for theirbiomagnification. The last theme addressed in this work was the analysis of newly-identified cationicand zwitterionic PFAS ; preliminary evidence seem to dispel concerns about the bioaccumulationpotential of the latter.