Monitoring data for potable water in the R.M. of Macdonald regional water system indicates elevated levels of chlorine disinfection by-products (DBPs), trihalomethanes (THMs). Dissolved Organic Carbon (DOC) and chlorine dose are the key precursors for the formation of THMs. Currently, the DOC is not removed efficiently at the Sanford water treatment plant, which supplies the R.M.’s potable water distribution system. The raw water DOC concentration incoming to the plant varied from 8.9mg/L to 31.8mg/L during this study. Sanford treated water effluent contained an average DOC of 6.5mg/L and the THM levels ranged from 86.6ppb to 175.7ppb. One of the objectives of this study was to conduct jar tests to optimize Sanford’s water treatment process to improve removal of DOC. Optimization of the coagulation process successfully reduced the DOC level in the plant effluent by 51% during the summer and 34% in the winter. The DOC reduction resulted in a THM reduction of 73.5ppb in the summer and 59.9ppb during the winter. Results showed that removal of 1mg/L of DOC eliminates 26.8ppb of THMs in summer and 11.9ppb during the winter. Another goal of this project was to investigate the relationship between THMs and their precursors, which includes: water DOC, free chlorine residual, and the chlorine contact time. Water samples were strategically collected throughout the Sanford regional water distribution system; the samples were tested for DOC, UV254, SUVA, chlorine residual, and contact time. A linear relationship between THM formation and chlorine contact time (R2 of 0.92) was found. This indicates that the content of THMs can be decreased by reducing the amount of time the water stays in the distribution system.

The purpose of this study was to determinate what requirements there should be on refilling material used as soil remediation based on the soil environment, i.e. soil processes and factors important to soil-dwelling organisms. The study was conducted by investigating which parameters that is important for the soil environment and by comparing them with each other. To exemplify how the parameters may change in different locations, data for total organic carbon, dry matter (i.e. water content), and pH were analyzed from different locations before and after soil remediation. Dry matter, organic matter, pH, compaction, grain size, porosity and soil composition were found to have a significant impact on various soil processes and soil organisms. Field investigations were made to examine dry- and organic matter and pH. The results were indicating that dry matter increased and that the organic matter decreased when the area was refilled with a coarse material. This study showed that there should be requirements on the characteristics of refilling material such as; organic matter content, good water holding capacity, a pH that is as neutral as possible and that the soil should not be too compact. A conclusion from this study was that crushed rock may not be the optimal refilling material after soil remediation.

Mercury (Hg) is a known neurotoxin that is often found in concentrations exceeding safe consumption guidelines in aquatic biota. This is evident in northern Canada, where northerners consume significant amounts of animals such as beluga, seals and burbot. In the Mackenzie River Basin, recent increases in Hg concentration in many of these animals over the past 25 years have been observed. The warming climate, and with it, the changing carbon cycle, are hypothesised in this thesis to play a role in the increases. Within the context of the two major zones (mountainous and peatland), with distinct geomorphology, hydrology and geology, traditional fossil fuel exploration methods (Rock-Eval pyrolysis, organic petrography) have been employed in a novel manner on recent sediments to qualify and quantify the OM and several geochemical analyses have been used to determine the geochemical sources of Hg. The mountainous zone is composed mostly of refractory OM, from forest fire char and heavily reworked OM. It also contains, and fluxes, most of the Hg, which derives from oxidative weathering and erosion of widespread sulfide minerals. However, Hg from this zone is in chemical forms of limited bioavailability. The peatland zone has a greater proportion of labile OM, with higher concentrations of DOC and algal-derived OM. Lake-fed tributaries in this zone contain even higher proportions of labile OM. At one of these sites, the sediment core record shows that Hg has been increasingly associated with labile OM over time, due to increasing primary productivity accelerated by climate change, and is resulting in an increase in scavenged Hg. The temporal trend in algal-bound Hg in the sediment record matches very well with the temporal trend of Hg in burbot sampled from the area, providing one of the first and strongest lines of evidence for the climatic impact on Hg bioaccumulation in Arctic ecosystems.

The objective of drinking water treatment is to provide water which is free of pathogens, is chemically and biologically stable, and is of good aesthetic quality. Natural organic matter (NOM) is present in all natural waters and can make meeting these goals more challenging. Not only does it undergo adverse reactions with disinfectants such as chlorine, it also impacts the biological stability of water within the distribution system and contributes to undesirable aesthetic qualities such as taste and odour. NOM has also been implicated in membrane fouling, which continues to be a significant operational problem preventing wider implementation of this process. Due to its highly variable heterogeneous nature, NOM can be difficult to characterize in terms of its specific composition, however recent analytical advancements are allowing for a better understanding of its behaviour in water treatment. Two promising tools for NOM characterization include Liquid Chromatography Organic Carbon Detection (LC-OCD) and Fluorescence Excitation Emission Matrix (FEEM) analyses. In this research both techniques were applied to samples taken from five full scale facilities in Ontario, Canada over all four seasons. The source waters for these treatment locations consisted of both river (Grand River, Ottawa River) and Great Lake waters (Lake Huron, Lake Erie, Lake Ontario), and an additional raw source (Saugeen River) was also monitored. The plants all employed granular media filtration, but had differences including enhanced coagulation, ozonation, biofiltration and sand ballasted flocculation. Other relevant water quality parameters were also monitored (TOC, DOC, UV254, pH, conductivity etc.) as well as plant operating conditions (dosages, flows, filter run times etc.) to investigate their impact on removal of specific NOM fractions. Four of the waters (Grand River, Ottawa River, Lake Erie and Lake Ontario) were selected based on the initial survey due to their NOM composition, for bench scale ultrafiltration (UF) membrane fouling experiments. The experiments were run at constant flux for a period of five days, with an automated permeation cycle and backwash. The impact of biopolymers on hydraulically reversible and irreversible fouling was of specific interest. Important seasonal trends were identified for all waters, with biopolymer content increasing at higher temperatures. Useful comparisons could also be made between different treatment processes including conventional and enhanced coagulation. The enhanced process while significantly improving the removal of humic substances, was not beneficial in terms of biopolymer removal, suggesting a different removal mechanism for these two fractions. The removal of low molecular weight ozonation by-products during full scale biofiltration was well demonstrated, and other fractions (building blocks, biopolymers) had varying degrees of removal, which was more dependent on temperature. Principle component analysis (PCA), an advanced multivariate statistical method, was successfully applied to a FEEM data set containing five different waters at varying degrees of treatment. Three principle components related to humic-like, protein-like and particulate/colloidal material were identified, and served as useful complementary information to the LC-OCD results. The humic-like component was found to have relatively good correlation to the humic fraction from LC-OCD analysis, with some deviation in the post-ozonation samples (which underwent greater structural changes not captured by LC-OCD). The biopolymer fraction was shown to have good correlation to hydraulically reversible membrane fouling across all four waters. The same could not be said for hydraulically irreversible fouling for which a combined fouling layer (with particulate and colloidal material) is hypothesized. This research provides those working in the water treatment sector with greater insight into NOM behaviour during various levels of treatment. As biopolymers were demonstrated to impact hydraulically reversible fouling (relatively independent of water quality), their removal prior to membrane filtration could significantly extend operational cycles by extending time between backwashes, thereby reducing energy requirements. As biopolymers are also suspected in forming a combined fouling layer, their removal can potentially minimize chemical cleaning requirements (and extend the life cycle of the membranes). The removal of biopolymers through coagulation was well demonstrated. Biofiltration is also expected to perform well as a membrane pre-treatment due its ability to remove biopolymers and particulate/colloidal matter. The ability of biofiltration to control biological re-growth in the distribution system (by removing low molecular weight biodegradable products) was also shown using LC-OCD and FEEM analysis.

Natural organic matter (NOM) occurs ubiquitously in drinking water supplies and is problematic since it serves as a precursor to disinfection by-products (DBPs) formation. Stricter DBP regulations will drive utilities to consider advanced treatment processes for DBP control through NOM removal. Herein, the transformation of NOM in homogeneous (UVA/H2O2 and UVA/Fe/H2O2) and heterogeneous (UVA/TiO2) Advanced Oxidation Processes (AOPs) were studied. Organic matter from three different sources was investigated in this work, specifically a commercial humic acid, and two Australian surface water sources. The transformation of the organic matter as a result of oxidation was investigated through multiple analytical techniques, such as UV-Vis spectroscopy, DOC analysis, high performance size exclusion chromatography (HPSEC), resin fractionation, liquid chromatography with organic carbon detection (LC-OCD) and disinfection byproducts formation potential. The multi-analysis approach is required due to the complex and heterogeneous nature of NOM. Each analytical technique provides complementary information on different properties of NOM, leading to a comprehensive understanding on how AOPs transform the chemical and physical properties of NOM. Both homogeneous and heterogeneous AOPs were found to be effective for NOM removal. However, complete mineralisation was not achieved, even under prolonged irradiation. Large aromatic and hydrophobic organics were degraded into lower molecular weight hydrophilic compounds, which had weak UV absorbance at 254 nm. In the UVA/TiO2 treatment, multi-wavelength HPSEC analysis demonstrated the formation of low molecular weight compounds with strong absorbance at wavelength lower than 230 nm. These residual organic compounds, though recalcitrant, had a low reactivity to chlorine to form THMs, and were identified to be low molecular weight acids and neutral compounds from LC-OCD analysis. Finally, the current work reports the novel synthesis of magnetic photocatalyst for NOM oxidation from low cost precursors to solve the separation problem of nano-sized particles. Magnetite particles were coated with a layer of protective silica from sodium silicate precursor. Photoactive titanium dioxide was then deposited onto the silica coated particles using titanium tetrachloride precursor. The as-prepared magnetic photocatalyst exhibited excellent stability and durability. Although the photoactivity of the magnetic photocatalyst is lower than commercial TiO2 photocatalyst, it can be easily recovered by magnetic field.

Membrane processes are increasingly used in water treatment. Experiments were performed using stirred cell equipment, polymeric membranes and synthetic surface water containing natural organics, inorganic colloids and their aggregates, and cations. All processes could remove a significant amount of natural organics. Pretreatment with ferric chloride was required to achieve significant organic removal with MF and high MWCO UF. Additionally, fouling mechanisms for the three processes were investigated. Crucial parameters were aggregate characteristics (fractal structure, stability, organic-colloid interactions), solubility of organics and calcium, and hydrodynamics. In MF, fouling by pore plugging was most severe. Variations in solution chemistry changed the aggregation state of the colloids and/or natural organic matter and dramatically affected rejection and fouling behaviour. UF membrane fouling was mainly influenced by pore adsorption and could improve natural organics rejection significantly. Coagulant addition shifted fouling mechanism from pore adsorption to cake formation. Aggregate structure was most significant for flux decline. In NF, rejection of natural organics involved both size and charge exclusion. Fouling was caused by precipitation of a calcium-organic complex. Fouling could be avoided by pretreatment with metal salt coagulants. Thorough chemical characterisation of the organics used demonstrated that only size and aromaticity can be related to fouling. The study is concluded with a process comparison based on a water quality parameter and a cost comparison. Treatment cost of microfiltration with chemical pretreatment was similar to that of nanofiltration at a comparable natural organics rejection.

The structure and function of microbial communities are critical to the maintenance and sustainability of terrestrial ecosystem processes. Consequently, there is substantial interest in assessing how microbial communities respond to various land management practices, and if alterations to the characteristics of microbial communities has the potential to disrupt ecosystem processes. This thesis was conducted to identify the long term effects of fertilisation and different levels of post-harvest organic matter removal on the characteristics of the FH litter and soil microbial communities in six, second rotation Pinus radiata plantation forests located around New Zealand. The six sites, established between 1986 and 1994, were sampled in 2002 and 2003. Various physical and chemical properties of the sites were measured, and litterfall production was determined. The microbial biomass in the FH litter layer and soil was determined by chloroform fumigation-extraction, and Biolog plates were used to assess the relative differences in microbial community diversity, based on patterns of substrate utilisation. Fertilisation substantially altered the physical and chemical properties of the forest floor, including FH litter moisture content, mass, carbon content, nitrogen content and carbon: nitrogen ratio and soil pH, nitrogen content and carbon: nitrogen ratio. The same range of FH litter and soil properties were also significantly changed by different levels of organic matter removal. The biomass and diversity of the FH litter and soil microbial communities were significantly altered by fertilisation and organic matter removal, and the differences in the microbial community characteristics were significantly correlated to the effects of the fertilisation and organic matter removal treatments on the physical and chemical environment in the majority of cases. The physical and chemical properties of the sites were significantly correlated to estimates of wood production, and it was also found that the characteristics of the microbial community were strongly related to productivity at several sites. The results demonstrated that fertilisation and organic matter removal regimes have had long term effects on the microbial communities at the sites. The persistence of the effects of the organic matter removal treatments were particularly noteworthy, as these treatments were applied at site establishment, and despite no subsequent reinforcement over the life of the trials, were still substantially influencing the physical, chemical and microbiological properties of the FH litter and soil up to 17 years later. The results of this thesis also emphasised the value of long-term experiments in assessing the effects of disturbance on the physical, chemical and microbiological characteristics of forest ecosystems. Further research into the specific nature of the relationship between site productivity and microbial community characteristics was suggested as an important focus for future studies.

Contaminated soils and sediments have been identified as significant secondary sources of organic contaminants.  Leaching tests may be useful tools to estimate the mobility of contaminants via the water phase and thereby the risk for groundwater and surface water contamination. The influence of soil composition (peat and clay content) on the leachability was investigated in batch leaching experiments for chemically diverse hydrophobic organic compounds (HOCs: PCP, PAHs, HCB, HCHs, PCBs, and TCDD/Fs). The above mentioned compounds were analyzed by both GC-LRMS (gas chromatography coupled with low resolution mass spectrometry (GC-HRMS) and GC-HRMS (gas chromatography coupled with high resolution mass spectrometry). Also the the leachability of eleven selected PCBs from naturally aged soil (Västervik, Sweden) was investigated in relation to the composition and concentration of dissolved organic matter at different pH (2 to 9), using a pH static test with initial acid/base addition. The the composition and of dissolved organic matter (DOM) at different pH values was explored by FTIR spectroscopy. The results were evaluated by orthogonal projections to latent structures (OPLS). Generally, for all model compounds studies, the Kd-values showed a variability of 2-3 orders of magnitude depending on the matrix composition. The Kd-values of moderately hydrophobic compounds, (e.g. HCHs, PCP and Phe), were correlated mainly with the organic matter content of soil. For more hydrophobic compounds (e.g.BaA, HCB and PCB 47), the leachability decreased as the proportions of  OM and clay contents increased. The Kd-values of 1,3,6,8-TCDD and 1,3,6,8-TCDF were  positively correlated with peat content but negatively correlated with clay content, while for PCB 153 and PCB 155 the correlations were reversed. The log Kd-values of all target PCBs decreased with increased pH values and the log Kd-values were highly correlated with the concentration of total organic carbon (TOC) in the leachates. The FTIR analysis of DOM showed that the least chlorinated and hydrophobic PCB congeners (i.e. PCB 28) might be associated with the hydrophilic fraction (i.e. carboxylic groups) of DOM. Our study demonstrated how complex interaction between the organic matter, clay components, pH and DOC influences the leachability of HOCs in a compound-specific manner.

Cette thèse a pour objectif de tester l’intérêt des spéléothèmes en tant qu’archive pédologique dans le but de reconstruire l’histoire des sols à haute-résolution durant la période Holocène. Il s’appuie sur une partie expérimentale visant à tester la robustesse des proxies organiques comme indicateurs des variations environnementales au cours du temps, et sur l'utilisation des indicateurs robustes pour reconstruire l'évolution de l'environnement dans les Bauges durant les 6000 dernières années.Le d13C de la matière organique (MO, indicateur de la dynamique de la MO dans les sols) et les lipides (indicateurs des contributions des différentes sources) ont été analysés en complément du d13C de la calcite. Les Hydrocarbures Aromatiques Polycycliques (HAP) ont également été utilisés comme molécule sonde pour comprendre le transfert des différentes molécules organiques, et comme indicateur des combustions passées, naturelles ou anthropiques. Une attention particulière a été portée à l’optimisation de la méthode analytique, afin que la résolution temporelle des analyses soit compatible avec les questions environnementales. Les résultats obtenus pour ces proxies ne sont pas exploitables et montrent un manque de robustesse attribué à des problèmes analytiques (d13CMO, lipides), au type d’alimentation des spéléothèmes (HAP) ou a des effets de site (d13C calcite).L’analyse de fluorescence UV en phase solide a été utilisée pour obtenir un enregistrement haute-résolution des variations semi-quantitatives et qualitatives de la MO. Un protocole a été développé pour quantifier l’intensité de fluorescence en phase solide (FPS). L'intensité de fluorescence en phase liquide d'extraits de MO des sols et des spéléothèmes ont été couplées par un modèle non linéaire à la FPS à haute résolution. Cette méthode a permis d’obtenir une chronique des flux de MO exportée depuis les sols sur une stalagmite test, provenant du Vercors (Grotte de Choranche) et couvrant les 400 dernières années.Un enregistrement composite de l’intensité de fluorescence et du d18O a été créé à partir de trois spéléothèmes du massif des Bauges (salle du Précieux, réseau Garde-Cavale) se recoupant sur les derniers 6000 ans, et a permis l’interprétation des variations du paléoenvironnement. Celles-ci montrent une réponse de l’environnement aux forçages climatiques, basculant vers un forçage anthropique au cours du temps.Cette étude démontre qu’il est possible d’obtenir un enregistrement haute-résolution de l’histoire des sols à l’échelle de la période Holocène par l’utilisation de la FPS. Le couplage avec des proxies organiques plus informatifs a cependant montré la limite de l’utilisation de ces derniers, due à leur manque de robustesse. La combinaison du signal de FPS avec le d18O des spéléothèmes a tout de même permis de réaliser une interprétation des variations environnementales durant l’Holocène. Celle-ci pourrait être améliorée en intégrant d’autres traceurs inorganiques (terres rares, éléments traces) qui n’ont pu être analysés durant cette thèse. / This thesis aims to demonstrate the interest of speleothems as pedologic archives to reconstruct high resolution soil history during the Holocene. Experimental study was applied to test proxies robustness as environmental tracers. These robust tracers are used to reconstruct environmental evolution in the Bauges Massif during the last 6000 years.Organic matter (OM) d13C (tracer of OM dynamic in soils) and lipids (tracers of source contributors) were analyzed complementary to the d13C of calcite. Polycyclic Aromatic Hydrocarbons (PAH) were used as a “probe” to understand organic molecular transport from soils, and to record past natural and anthropogenic combustions. Attention was paid on the optimization of extraction method in order to obtain a temporal resolution suitable for environmental issues. Results obtained are not workable because of their lack of robustness attributed to analytical issues (d13COM, lipids), to speleothem water feeding type (PAH), or to site-specific effect (d13C).OM semi-quantitative and qualitative variations were recorded at high resolution using the solid-phase fluorescence (SPF) analysis. A protocol was developed to quantify the fluorescence intensity obtained with SPF. Liquid-phase fluorescence intensity of soil and stalagmite OM extracts was coupled with high resolution SPF using a non linear model. OM fluxes record was obtained for a stalagmite-test from the Vercors Massif (last 400 years).A composite record of SPF intensity and d18O was created from 3 stalagmites from the Bauges Massif (Précieux room, Garde-Cavale system), spanning the last 6000 years. It enabled the interpretation of paleoenvironmental variations which shows a change from a climatic to anthropogenic control.This study shows that SPF is a reliable tool to record soil history during Holocene with high resolution. However, organic proxies coupling highlights the limit of their use, induced by a weak robustness. Combination of SPF and d18O enabled to reconstruct environmental variations during the Holocene. This interpretation could be improved by integrating other proxies such as rare earths or trace elements, which could not have been tested during this work due to experimental issues.

Algal bloom can significantly impact reverse osmosis desalination process and reduce the drinking water production. In 2008, a major bloom event forced several UAE reverse osmosis plants to stop their production, and in this context, a better understanding of UF membrane fouling caused by algal organic matter (AOM) is needed, in order to adjust the filtration conditions during algal bloom events. Polymeric MF/UF membranes are already widely used for RO pretreatment, but ceramic UF membranes can also be an alternative for the filtration of marine algal solutions. The fouling potential of the Red Sea and the Arabian Sea, sampled at different seasons, along with four algal monocultures grown in laboratory, and one mesocosm experiment in the Red Sea was investigated. Algal solutions induce a stronger and more irreversible fouling than terrestrial humic solution, toward ceramic membrane. During algal bloom events, this fouling is enhanced and becomes even more problematic at the decline phase of the bloom, for a similar initial DOC. Three main mechanisms are involved: the formation of a cake layer at the membrane surface; the penetration of the algal organic matter (AOM) in the pore network of the membrane; the strong adhesion of AOM with the membrane surface. The last mechanism is species-specific and metal-oxide specific. In order to understand the stronger ceramic UF fouling at the decline phase, AOM quality was analyzed every two days. During growth, AOM is getting enriched in High Molecular Weight (HMW) structures (> 200 kDa), which are mainly composed by proteins and polysaccharides, and these compounds seem to be responsible for the stronger fouling at decline phase. In order to prevent the fouling of ceramic membrane, coagulation-flocculation (CF) using ferric chloride was implemented prior to filtration. It permits a high removal of HMW compounds and greatly reduces the fouling potential of the algal solution. During brief algal bloom events, CF should be implemented prior to UF to protect the membranes. A comparison between polymeric and ceramic UF membranes showed that ceramic membrane suffers from a stronger fouling but permits a better removal of DOC and particularly HMW compounds.