Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-02-02T17:29:36Z No. of bitstreams: 1 TESE_FINAL.AlineMansur.04092016.pdf: 3671406 bytes, checksum: 0deab42bbd5b80baf1c0a321d755a707 (MD5) / Made available in DSpace on 2017-02-02T17:29:36Z (GMT). No. of bitstreams: 1 TESE_FINAL.AlineMansur.04092016.pdf: 3671406 bytes, checksum: 0deab42bbd5b80baf1c0a321d755a707 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fundação de Amparo à pesquisa do Estado do Rio de Janeiro / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geociências- Geoquímica Ambiental. Niterói, RJ / As estações de tratamento de água (ETA) são projetadas para fornecer água continuamente, de maneira a atender a critérios de potabilidade. No entanto, além da água tratada e potável, essas estações são igualmente produtoras de resíduo, o material em suspensão decantado da água, reconhecido como resíduo de Estações de Tratamento de Água, ou resíduo de ETA. O descarte direto de resíduos de ETA em corpos d`água deve ser evitado, considerando que a essas descargas podem comprometer a qualidade da água, podendo gerar efeitos crônicos na comunidade aquática O Reservatório de Juturnaíba, considerado o segundo maior reservatório de água do estado do Rio de Janeiro, foi o repositório final dos resíduos produzidos por duas Estações de Tratamento de Água por cerca de 30 anos. Estes resíduos foram descartados nas margens do reservatório, podendo comprometer a qualidade da água e do sedimento do reservatório. Este estudo teve como objetivo avaliar se a disposição de resíduos de ETAs nas margens do reservatório causou contaminação no ambiente, através do estudo sobre mobilidade de metais (Al, Fe, Mn, Zn, Cr, Cu e Ni) entre os compartimentos: resíduos de ETAs, sedimentos superficiais e água do reservatório. Foram realizadas análises quantitativas e qualitativas dos resíduos de ETAs, bem como uma avaliação diagnóstica dos sedimentos superficiais adjacentes as áreas de descarte de resíduos. Através de modelos digitais de terreno construídos no software Surfer® e por equações matemáticas usando dados declarados pela empresa, foi possível calcular os volumes de resíduos presentes nas margens do reservatório, totalizando em cerca de 60.370 e 62.479 toneladas de resíduos em cada pilha de resíduo. Método de extrações de metais foram aplicados, para elucidar o teor pseudo-total (USEPA 3051A) e as frações geoquímicas dos metais (extração sequencial - BCR) nos resíduos de ETAs e nos sedimentos adjacentes a área de descarte. O fracionamento geoquímico de metais mostrou que existe uma a variação espacial entre os sedimentos localizadas próximos e distantes das áreas de descarte de resíduos. Os sedimentos localizados distantes da área de descarte não mostraram anomalias nas concentrações de metais, estando os metais Al, Fe, Zn e Cr associados predominantemente à fração residual (F4). O fracionamento do Al apresentou ser um bom traçador da presença de resíduos de ETA em sedimentos, já que apenas nos sedimentos localizados próximos aos resíduos, esse metal esteve predominantemente associado às frações prontamente mobilizáveis (F1+F2+F3) do sedimento, com elevadas concentrações na fração ácido-solúvel (F1). Assim, através do modelo de atenuação das concentrações pseudo-totais de Al no sedimento, aliado as avaliações de fracionamento geoquímico desse metal no sedimento, foi possível delimitar a área de abrangência da contaminação do sedimento, provenientes da dispersão espacial dos resíduos de ETAs. Experimentos usando microcosmos foram realizados para avaliar a dessorção de metais entre resíduo de ETA e a água do Reservatório, sob diferentes condições físico-químicas. Esses experimentos mostraram que o contato direto do resíduo com a água propicia a liberação de Al, Fe e Mn, e que a acidificação e o incremento de ácido húmico dissolvido na água favorece a dessorção do Al do resíduo. Conclui-se que a contaminação do sedimento por resíduos de ETAs está restrita a pequenas áreas localizadas próximas aos descarte de resíduo. No entanto, devido a proporção de Al associada as frações prontamente mobilizáveis do resíduo, a presença de resíduos de ETAs em contato direto com a água do reservatório, funciona como uma fonte pontual de Al para o ambiente. / Water treatment plants (WTP) are conceived to continuously produce clean water, responding to defined criteria of portability. However, besides treated and potable water, water treatment plants produce sludge resulting from decantation of the suspended matter that are disposed in the environment. The discharge of the water treatment residue into aquatic ecosystems may cause negative environmental impact on the natural water quality and chronic effects in the aquatic community. Juturnaíba Lake is an important water reservoir in Rio de Janeiro. For about 30 years, the residue generated by two Water Treatment Plants, were systematically discarded in two restricted areas in the Juturnaíba Reservoir edges. In direct contact with water, this residues may have been spread throughout the reservoir, affecting water and sediment quality. The aim of this study was to access the contamination of the Juturnaíba Reservoir, by evaluating the mobility of the metals (Al, Fe, Mn, Zn, Cr, Cu e Ni), between sludge, sediment, and water spatial and geochemical distribution of metals, mainly the Al, in the superficial sediments. Quantitative and qualitative analysis were performed, as a diagnostic evaluation of surface sediments adjacent waste disposal areas. The calculated mass of the residues piles are similar and respectively 60.3170 e 62.479. The residue mass was calculated based on the model terrain digital model and mathematical equations, which provided the following measures 60.370 e 62.479 tons in each piles of residue. Pseudo-total metal in sediment was assessed after aqua regia inverted digestion, with microwave assistance (EPA 3051A). The BCR sequential extraction procedure was applied, and geochemical fractions of Al, Fe, Mn, Zn, Cu, Cr e Ni were determined. The geochemical fractionation of metals showed that there is a spatial variation between near and far located sediments of residue disposal areas. In distant located sediments of the waste disposal area, the highest percentages Al, Zn, Fe and Cr was found in the residual fractions (F4), meaning that these metals were strongly bound to the sediments. Fractionation Al showed to be a good marker for the presence of ETA waste sludge, since only in the sediments located near the waste sludge, had aluminum predominantly associated with the mobile fractions (F1 + F2 + F3), with high concentrations in the acid-soluble fraction (F1). Through the model of attenuation of Al pseudo-total concentration in the sediment and along the geochemical fractionation assessments of Al in the sediments, it was possible to delimit the area of extent of sediment contamination, from the spatial dispersion of water treatment residue. Experiments using microcosms were performed to evaluate the desorption of metals from the residue and water reservoir under different physicochemical conditions. These experiments showed that the direct contact of the residue with water, promotes the release of Al, Fe and Mn, and that the acidification and the increase of humic acid dissolved in the water favor the desorption of Al present in the residue. The results show that the residue affected the sediment quality, although this contamination does not spread uniformly through the reservoir. It was concluded that the sediment contamination by water treatment residue is restricted to small areas located close to residue disposal. However, because the proportion of the Al associated with the mobility fractions, the presence of such residues in direct contact with the reservoir water,acts as a source of Al to the environment.

La forte augmentation de la population mondiale entraîne une demande croissante en eau potable. La production d'eau potable est accompagnée par la génération de résidus du traitement de l'eau dont la boue d'aluminium qui est donc largement disponible mondialement. Ce travail se concentre sur l'identification des différentes voies de valorisation des boues d'aluminium afin de les réutiliser dans le domaine de l’environnement. Deux sources de boues d'aluminium, collectées en France et en Irlande, ont été étudiées dans divers domaines d’application en fonction de leurs caractéristiques. Tout d'abord, les boues d'aluminium ont été utilisées en remplacement d’une partie de l'argile dans la fabrication des briques, en incorporant différents pourcentages de boues d'aluminium et à différentes températures. Les briques résultantes ont été caractérisées et les résultats ont montré que les briques composées de boues d'aluminium et d'argile sont conformes aux « normes européennes et irlandaises » et démontrent ainsi le potentiel pour une application industrielle des boues d'aluminium dans la fabrication de briques en terre cuite irlandaises. Dans un second temps, les boues d’aluminium ont été utilisées comme adsorbant des polluants présents dans l’agriculture. Le glyphosate est un ingrédient actif dans les pesticides utilisés massivement dans l'agriculture irlandaise et représente une problématique environnementale. La boue d’aluminium et la tourbe irlandaise ont été comparées pour l’élimination du glyphosate lors de tests en pot à l’échelle laboratoire. Les résultats ont montré que la boue d’aluminium permet d’éliminer le glyphosate à plus de 99% et réduire les niveaux de DCO. Cet aspect scientifique a permis d’être dans la sélection des adsorbants possibles pour le traitement des eaux usées agricoles en Irlande. Le co-conditionnement et la déshydratation des boues de station d’épuration avec des boues d’aluminium liquides ont également été étudiés. Pour cela, le Jar test a été effectué sur des boues issues d’une station de traitement des eaux française. Les résultats ont montré que le rapport optimal de mélange des boues est de 1:1 (boues d’épuration : boues d’aluminium). Ainsi, la quantité de polymère utilisée peut être diminuée de 14 fois par rapport aux technologies actuelles. Cette approche a permis de montrer la possible valorisation des boues d’aluminium comme un moyen durable et technique permettant ainsi l’élimination des boues localement pour une même station de traitement des eaux. Une autre voie de valorisation des boues d’aluminium comme adsorbant pour la purification des gaz a été étudiée lors d’expériences d’adsorption de H2S dans un réacteur à lit fixe dans différentes conditions expérimentales. Les données expérimentales d’adsorption du H2S ont été modélisées à l'aide de modèles empiriques basés sur la cinétique des processus d'adsorption. Les résultats ont montré que les boues d'aluminium sont un adsorbant efficace pour l'élimination du H2S (capacité de 374,2 mg H2S / g solide) et que des mécanismes mis en jeu sont l'adsorption dissociative et l'oxydation. Les coefficients de transfert de masse globaux ont également été calculés et pouvant ainsi être utilisés pour la prédiction. Enfin, les gâteaux de boues d'aluminium ont été réutilisés pour la purification simultanée d’H2S et le traitement des eaux usées. Les résultats ont montré la capacité de cet adsorbant pour éliminer tout le H2S présent avec une grande efficacité d’élimination de la DCO, TN et TP. Ainsi, il a été démontré la valorisation des boues d’aluminium en tant qu’adsorbant pour une purification du H2S simultanée avec le traitement des eaux usées. / The production of drinking water always accompanied by the generation of water treatment residues (WTRs). Alum sludge is one of the WTRs, it is an easily, locally and largely available by-product worldwide. This work focuses on the identification of different ways to valorize the alum sludge for environmentally friendly reuse. Two alum sludges collected from France and Ireland have been reused in various fields as a function of their characteristics. Firstly, alum sludge was used as a partial replacement for clay in brick making, by incorporating different percentages of alum sludge and calcined at different temperatures (range from 800 to 1200 °C). The resultant bricks were tested for compression, Loss on Ignition, water absorption, appearance, etc. Results show that alum sludge-clay bricks have met the “European and Irish Standards” and demonstrated the huge industrial application potential for alum sludge in Irish clay brick manufacturing. Glyphosate is an active ingredient in pesticide which is massive employed in agriculture. Alum sludge and Irish peat were compared for glyphosate removal in pot tests, results show that alum sludge present significant glyphosate removal capacity (>99 %) and could reduce the level of Chemical Oxygen Demand (COD). It provided a scientific clue for sorbents selection when considering the agricultural wastewater treatment in Ireland and to maximize their value in practice. The co-conditioning and dewatering of sewerage sludge with liquid alum sludge was also investigated in Jar-test based on the case analysis of a water industry in France. Results show that the optimal sludge mix ratio is 1:1, the use of the alum sludge has been shown to beneficially enhance the dewaterability of the resultant mixed sludge, and highlighting a huge polymer saving (14 times less than the current technologies) and provided a sustainable and technical sludge disposal route for the local water industry. The use of alum sludge as a sorbent for gas purification was studied by H2S adsorption experiments in a fixed-bed reactor with various operating parameters. The experimental breakthrough data were modeled with empirical models based on adsorption kinetics. Results show that alum sludge is an efficient sorbent for H2S removal (capacity of 374.2 mg/g) and the mechanisms including dissociative adsorption and oxidation were proposed. Moreover, the overall mass transfer coefficients were calculated which could be used for the process scaling up. Finally, alum sludge cakes were reused in the novel aerated alum sludge constructed wetland (CW), which were designed for simultaneous H2S purification and wastewater treatment. Results show that H2S was completely removed in the six months’ trials, while the high removal efficiencies of COD, total nitrogen (TN), total phosphates (TP) were achieved. Thus, a novel eco-friendly CW for simultaneous H2S purification and wastewater treatment was developed. In the different approaches and process considered, in particular it was put in investigating and describing the mechanisms involved. Overall, this work demonstrated alum sludge could be a promising by- product for various novel beneficial reuse rather than landfilling and provided a “Circular Economy” approach for WTRs management.

No description available.

No description available.

Les travaux présentés dans ce manuscrit de doctorat s'inscrivent dans la thématique du stockage inter-saisonnier de l'énergie solaire thermique pour l'habitat et le tertiaire (eau chaude sanitaire et chauffage). Le stockage thermochimique en air humide est une des solutions les plus prometteuses, en particulier avec un réacteur à lit fixe. Le bromure de strontium et l'alun de potassium ont été sélectionnés comme réactifs pour leurs caractéristiques énergétiques lors de réactions d'hydratation et de déshydratation. L'étude est constituée d'avancées théoriques, de nombreuses expérimentations et d'un modèle numérique détaillé. Une étude thermodynamique a démontré l'existence d'une droite de charge qui relie les conditions d'entrée et de sortie de l'air humide au passage du réactif. Les équations régissant les réactions chimiques, les transferts massiques et thermiques et la conservation de la quantité de mouvement ont été établies et un modèle numérique monodimensionnel couplant ces phénomènes a été développé. Des essais sur différents échantillons des deux sels et pour divers conditions opératoires ont été effectués dans le but de comprendre les phénomènes physico-chimiques ainsi que pour valider l'étude théorique et le modèle numérique. / This PhD thesis focuses on seasonal solar thermal energy storage for household applications such as production of heat and domestic hot water. Thermochemical storage was chosen for that purpose. The specific solid/gas reactions with water vapor, also called hydration/dehydration reactions, were used with a multi-scale global approach. The level of the reactor was identified as the critical level of that multi-scale approach. As a consequence, the integrated fixed-bed reactor technology in a moist air open loop system was adopted. A theoretical, experimental and numerical methodology was used for the study where strontium bromide and potassium alum salts were chosen as reactive materials. The corresponding reactions are: + 5 (H2O) ↔ (with Δhr=67.4 kJ/molwater and Δsr=175 J/K.molwater) + 9 (H2O) ↔ < KAl(SO4)2.12H2O > (with Δhr=44.2 kJ/molwater and Δsr=109.8 J/K.molwater) The first salt exhibits very good thermochemical properties. On the other hand, the main advantages of potassium alum are its low cost and the fact that it presents no sanitary risk. More than 30 cycles with 3 different samples of potassium alum and more than 25 cycles with 4 samples of strontium bromide under various stationary and dynamic operating conditions were carried out in order to understand the phenomena. The main experimental results were the following ones: • A very good stability and reproducibility of physical and chemical phenomena was observed for both materials. • A thermal reaction front was also observed. • A thermal hysteresis for both salts was found. • Based on that last observation a theoretical equation named charge-discharge line was developed. Experimental results with both salts validate the charge-discharge line theory. • A correlation between reaction kinetics, temperature rise due to the reaction, power of the reaction and the operating conditions was observed. The criterion for that correlation is the affinity of the reaction. A proportional correlation between affinity and reaction kinetics, temperature rise and power of the reaction was observed. • Spontaneous hydration and over-hydration reactions do not produce any particular difficulties or problems. • Pressure drop through the reactor and evolution of salts volume were also measured. Experimental energy density was measured in the range of 350 kWh/m3 for strontium bromide and 240 kWh/m3 for the potassium alum. • In general, strontium bromide is a very good candidate material for seasonal storage, while potassium alum cannot provide satisfying temperature rise and power. The equations governing those phenomena were also established and used to develop a 1D numerical model with partial differential equations coupling chemical phenomena, mass and thermal transfer phenomena and momentum conservation. Verification, validation and confirmation of this model under a very large range of operating conditions were carried out based on the experimental results of strontium bromide. A total of 19 different test cases were studied in order to validate the numerical model. The effect of humidity, temperature, quantity of reactive material and air flow were studied both for stationary and dynamic conditions. The numerical model was able to provide very satisfying results.

Lead is a known toxin, with the ability to accumulate in the human body from as early as fetal development. Lead exposure is known to cause a myriad of health effects which are more prominent among children. Health effects upon exposure can range from renal and heart disease or potentially cancer in adults to neurotoxicity in children. The continued presence of old lead service lines and plumbing in distribution systems as well as lead-containing solders and brass fixtures in homes may contribute lead to drinking water. Recent studies have highlighted the importance of a predictor known as the chloride-to-sulfate mass ratio (CSMR) in controlling lead release. A ratio above 0.5 – 0.6 theoretically increases the aggressiveness of lead leaching in galvanic settings, while a lower ratio controls lead corrosion. A switch in coagulant type could significantly alter the ratio. However, a coagulant switch could also trigger changes in finished water turbidity and organics, including disinfection by-product (DBP) precursors, as well as impact sludge production. Anecdotal evidence from an Ontario water treatment utility suggested the potential applicability of a newly formulated polymer, cationic activated silica (CAS), in improving DBP precursor removal when used in concurrence with a primary coagulant. No previous scientific research had been dedicated to testing of the polymer. The present research had three primary objectives: The first was to investigate the effect of conventional coagulation with six different coagulants on the chloride-to-sulfate mass ratio as it pertains to lead corrosion in two Ontario source waters of differing quality. Additionally, the effect of coagulant choice on pH, turbidity, and organics removal was investigated. The second objective was aimed at testing potential reductions in CSMR and organics that could be brought about by the use of two polymers, cationic and anionic activated silica (CAS and AAS, respectively), as flocculant aids. Finally, the performance of a high-rate sand-ballasted clarification process was simulated at bench-scale to gauge its performance in comparison with conventional coagulation simulation techniques. The first series of jar-tests investigated the effectiveness of CAS as a primary coagulant on Lake Ontario water. In comparison with the conventional coagulants aluminum sulfate and polyaluminum chloride, CAS did not offer any apparent advantage with respect to turbidity and organics removal. Testing of CAS and AAS as flocculant aids was also conducted. Results from a full factorial experiment focused on CAS testing on Lake Ontario water showed that coagulant dose is the most significant contributor to CSMR, turbidity, DOC removal, and THM control. Generally, improvements resulting from CAS addition were of small magnitude (<15%). Reductions in CSMR were attributed to the presence of the sulfate-containing chemicals alum and sulfuric acid in the CAS formulation. Testing of sulfuric acid-activated AAS on Grand River water showed that pairing of AAS with polyaluminum chloride provides better results than with alum with respect to DOC removal (39% and 27% respectively at 60 mg/L coagulant dose). Highest turbidity removals (>90%) with both coagulants were achieved at the tested coagulant and AAS doses of 10 mg/L and 4 mg/L respectively. CSMR reductions in the presence of AAS were also attributable to sulfate contribution from sulfuric acid. Bench-scale simulation of a high-rate sand-ballasted clarification process on Grand River water showed comparable removal efficiencies for turbidity (80 – 90% at 10 mg/L), and DOC (30 – 40% at 50 mg/L). Finally, six different coagulants were tested on the two source waters for potential applicability in CSMR adjustment in the context of lead corrosion. The two chloride-containing coagulants polyaluminum chloride and aluminum chlorohydrate increased CSMR in proportion to the coagulant dose added, as would be expected. Average chloride contribution per 10 mg/L coagulant dose was 2.7 mg/L and 2.0 mg/L for polyaluminum chloride and aluminum chlorohydrate, respectively. Sulfate-contributing coagulants aluminum sulfate, ferric sulfate, pre-hydroxylated aluminum sulfate, and polyaluminum silicate sulfate reduced CSMR as coagulant dose increased, also as would be expected. The highest sulfate contributors per 10 mg/L dose were pre-hydroxylated aluminum sulfate (6.2 mg/L) and ferric sulfate (6.0 mg/L). The lowest CSMR achieved was 0.6 in Lake Ontario water at a 30 mg/L dose and 0.8 in Grand River water at a 60 mg/L dose. Highest DOC removals were achieved with the chloride-containing coagulants in both waters (35 – 50%) with aluminum chlorohydrate showing superiority in that respect. DOC removals with sulfate-containing coagulants were less, generally in the range of 22 – 41%. Specificity of critical CSMR values to source water needs to be investigated. Additionally, long term effects of sustained high or low CSMR values in distribution systems need to be further looked into. Finally, the effect of interventions to alter CSMR on other water quality parameters influencing lead corrosion such as pH and alkalinity still represent a research deficit.

Lead is a known toxin, with the ability to accumulate in the human body from as early as fetal development. Lead exposure is known to cause a myriad of health effects which are more prominent among children. Health effects upon exposure can range from renal and heart disease or potentially cancer in adults to neurotoxicity in children. The continued presence of old lead service lines and plumbing in distribution systems as well as lead-containing solders and brass fixtures in homes may contribute lead to drinking water. Recent studies have highlighted the importance of a predictor known as the chloride-to-sulfate mass ratio (CSMR) in controlling lead release. A ratio above 0.5 – 0.6 theoretically increases the aggressiveness of lead leaching in galvanic settings, while a lower ratio controls lead corrosion. A switch in coagulant type could significantly alter the ratio. However, a coagulant switch could also trigger changes in finished water turbidity and organics, including disinfection by-product (DBP) precursors, as well as impact sludge production. Anecdotal evidence from an Ontario water treatment utility suggested the potential applicability of a newly formulated polymer, cationic activated silica (CAS), in improving DBP precursor removal when used in concurrence with a primary coagulant. No previous scientific research had been dedicated to testing of the polymer. The present research had three primary objectives: The first was to investigate the effect of conventional coagulation with six different coagulants on the chloride-to-sulfate mass ratio as it pertains to lead corrosion in two Ontario source waters of differing quality. Additionally, the effect of coagulant choice on pH, turbidity, and organics removal was investigated. The second objective was aimed at testing potential reductions in CSMR and organics that could be brought about by the use of two polymers, cationic and anionic activated silica (CAS and AAS, respectively), as flocculant aids. Finally, the performance of a high-rate sand-ballasted clarification process was simulated at bench-scale to gauge its performance in comparison with conventional coagulation simulation techniques. The first series of jar-tests investigated the effectiveness of CAS as a primary coagulant on Lake Ontario water. In comparison with the conventional coagulants aluminum sulfate and polyaluminum chloride, CAS did not offer any apparent advantage with respect to turbidity and organics removal. Testing of CAS and AAS as flocculant aids was also conducted. Results from a full factorial experiment focused on CAS testing on Lake Ontario water showed that coagulant dose is the most significant contributor to CSMR, turbidity, DOC removal, and THM control. Generally, improvements resulting from CAS addition were of small magnitude (<15%). Reductions in CSMR were attributed to the presence of the sulfate-containing chemicals alum and sulfuric acid in the CAS formulation. Testing of sulfuric acid-activated AAS on Grand River water showed that pairing of AAS with polyaluminum chloride provides better results than with alum with respect to DOC removal (39% and 27% respectively at 60 mg/L coagulant dose). Highest turbidity removals (>90%) with both coagulants were achieved at the tested coagulant and AAS doses of 10 mg/L and 4 mg/L respectively. CSMR reductions in the presence of AAS were also attributable to sulfate contribution from sulfuric acid. Bench-scale simulation of a high-rate sand-ballasted clarification process on Grand River water showed comparable removal efficiencies for turbidity (80 – 90% at 10 mg/L), and DOC (30 – 40% at 50 mg/L). Finally, six different coagulants were tested on the two source waters for potential applicability in CSMR adjustment in the context of lead corrosion. The two chloride-containing coagulants polyaluminum chloride and aluminum chlorohydrate increased CSMR in proportion to the coagulant dose added, as would be expected. Average chloride contribution per 10 mg/L coagulant dose was 2.7 mg/L and 2.0 mg/L for polyaluminum chloride and aluminum chlorohydrate, respectively. Sulfate-contributing coagulants aluminum sulfate, ferric sulfate, pre-hydroxylated aluminum sulfate, and polyaluminum silicate sulfate reduced CSMR as coagulant dose increased, also as would be expected. The highest sulfate contributors per 10 mg/L dose were pre-hydroxylated aluminum sulfate (6.2 mg/L) and ferric sulfate (6.0 mg/L). The lowest CSMR achieved was 0.6 in Lake Ontario water at a 30 mg/L dose and 0.8 in Grand River water at a 60 mg/L dose. Highest DOC removals were achieved with the chloride-containing coagulants in both waters (35 – 50%) with aluminum chlorohydrate showing superiority in that respect. DOC removals with sulfate-containing coagulants were less, generally in the range of 22 – 41%. Specificity of critical CSMR values to source water needs to be investigated. Additionally, long term effects of sustained high or low CSMR values in distribution systems need to be further looked into. Finally, the effect of interventions to alter CSMR on other water quality parameters influencing lead corrosion such as pH and alkalinity still represent a research deficit.