O desempenho de unidades de flotação por ar dissolvido (FAD) depende significativamente do projeto da zona de contato (ZC) dessas unidades, situada na entrada das mesmas e responsável por promover condições adequadas para que ocorram taxas satisfatórias de colisão entre as microbolhas de ar e os flocos formados na etapa antecedente de floculação da água para abastecimento. Os dois principais parâmetros de projeto da ZC são o tempo de detenção hidráulico ou tempo de contato (Tzc) e o gradiente médio de velocidade na ZC (Gzc). A presente dissertação apresenta os resultados de estudo sobre a influência do Tzc e do Gzc na ZC de uma unidade piloto de flotação por ar dissolvido (UPFAD) com escoamento contínuo aplicada ao tratamento de água para abastecimento. Foram utilizados módulos contendo tela metálica em seu interior com malha de #25 mm com diferentes dimensões, de modo a se obterem diferentes valores de Gzc e Tzc. Foram investigadas duas configurações na unidade de FAD (Configurações A e B), nas quais o comprimento (Lzc) e a altura (Hzc) da ZC foram variados, permitindo a alteração do Tzc e mantendo-se controlados os valores de Gzc (com a introdução ou não de diferentes módulos de tela metálica na ZC) e vice versa. Os demais parâmetros do processo de FAD não sofreram variações, tais como taxa de aplicação superficial (TAS) na zona de separação, tempo de floculação, entre outros. Para a configuração A, foram estudadas três alturas diferentes na ZC e para a configuração B, quatro alturas diferentes na ZC, o que acarretou, para cada valor de Gzc variação do Tzc. Para cada configuração da ZC, também foram testados três valores de vazão de recirculação de água saturada com ar de modo a se obterem três diferentes concentrações de ar (A/V) no processo de flotação. Para todos os parâmetros analisados (Turbidez, Cor, Absorbância), as maiores eficiências de remoção foram obtidas nos ensaios realizados com o uso da tela #25 mm tanto na configuração A (TASzc = 136 m/h e G = 6,1 s-1) quanto na configuração B (TASzc = 87 m/h e G = 3,2 s-1). Os resultados permitem concluir que o par de valores (Tzc, Gzc) é mais apropriado para o projeto da zona de contato de unidades FAD do que o par (Tzc, TASzc) usualmente adotado pelos projetistas, sendo que, na faixa de valores investigados a UPFAD apresentou melhor desempenho para o par: Tzc de 41 s e Gzc de 6,1 s-1. / The performance of units dissolved air flotation (DAF) depend significantly of design on the contact zone (CZ) of these units, situated at the entrance thereof and responsible for promoting appropriate conditions to occur satisfactory collision rates between air microbubbles and the flocs formed in the step of flocculation of potable water. The two main design parameters of the CZ are the hydraulic detention time or contact time (Tcz) and the velocity gradient in the CZ (Gcz). This work presents the results of study of the effects of varying the Tcz and Gcz at the contact zone of pilot unit DAF with continuous flow applied to the treatment of potable water. Were used modules containing metal grille with mesh of #25 mm, with different dimensions in order to obtain different values of Gcz and Tcz. Were investigated two configurations in the unit FAD ( configurations A and B) where the length (Lcz) and height (Hcz) of contact zone were varied, allowing the variation of Tzc and keeping the values of Gcz controlled (with the introduction or not of different modules in the metal grille in CZ) and vice versa, without changes in other process variables FAD, such as rate of surface application (TAS) in the separation zone, flocculation time, among others. For the configuration A were studied three different heights in the CZ and in configuration B, four different heights in the CZ, which resulted, for each value of Gcz (relative to the chosen value of Lcz) the variation of Tzc. For each configuration of CZ were also tested three values of recirculation flow of air saturated in order to obtain three different values of concentration in air (A/V) in the flotation process. For all parameters analyzed (turbidity, color, absorbance), the highest efficiencies were obtained in assays performed using the grille #25 mm, both in configuration A (TAScz = 136 m/h and L = 6,1 s-1) and configuration B (TAScz = 87 m/h and G = 3,2 s-1). The results indicate that the pair of values (Tcz, Gcz) is more suitable for project of the CZ of units FAD than the pair (Tcz, TAScz) usually adopted by the designers, and values in the range investigated in UPFAD showed performed better for Tcz of 41 s and Gcz of 6,1 s-1.

O presente trabalho teve como objetivo estudar a influência do gradiente médio de velocidade (Gzc), associado ao tempo de detenção hidráulico (tzc) e à taxa de aplicação superficial (TASzc), na zona de contato, na eficiência de clarificação de uma unidade retangular de flotação por ar dissolvido, em escala piloto, tratando água para abastecimento. Foram estudadas duas configurações da Unidade Piloto de Flotação por Ar Dissolvido (UPFAD) (A e B), as quais diferem no comprimento da zona de contato A (90 mm) e B (140 mm). A TASzc - A (133 ± 3 m/h) e B (86 ± 1 m/h) - e o tzc - A (54 ± 1s) e B (84 ± 1 s) - são diferentes. Foram avaliados três valores do Gzc A (1,8; 6,5;10,2) e B (0,9; 4,7; 6,3), através da inserção de telas com características diferentes no interior da zona de contato. E, Para cada valor de Gzc, foram investigados três valores de A/V (3,73; 4,90; 6,41). Em todos os ensaios realizados, foram fixados os seguintes parâmetros: vazão da água bruta preparada (5,4 m³/h); temperatura da água bruta preparada (26 ± 1ºC); pH de coagulação (6,5 ± 0,1); tempo de floculação (17,2 min); gradiente médio de velocidade de floculação (110 s-1); vazão de descarte após a floculação (0,8 m³/h); vazão de entrada para a flotação (Qe) (4,6 m³/h); velocidade de entrada para a flotação (ve) (180 m/h); velocidade cross-flow (45 m/h); TASzs (14,6 ± 0,2 m/h); pressão de saturação (4,5 ± 0,1 Kgf/cm²). A unidade piloto FAD foi alimentada com água preparada, que apresentou turbidez em torno de 7,4 ± 0,6 UNT, e cor aparente, em torno de 39,4 ± 4,3 UH. A fração removida dos parâmetros analisados para cada Gzc é menos sensível a variações de A/V na configuração A que na configuração B. Na configuração A, a tela que apresentou Gzc em torno de 6,5 s-1 gerou melhores resultados para cada A/V analisado. Na configuração B, a tela que gerou Gzc em torno de 4,7 s-1 proporcionou melhor fração removida de turbidez e cor para cada A/V estudado. Além disso, na configuração B, a fração removida de turbidez e cor foi menos sensível a variações de A/V, para Gzc de 4,7 s-1 que para os demais valores de Gzc. A tela que gerou resultados mais eficientes na configuração A foi a mesma para a configuração B. Portanto o uso da referida tela favoreceu o desempenho das configurações A e B. Comparando todas as situações estudadas nas duas configurações, o ensaio com a configuração A (com tzc de 54 s) com Gzc de 6,3 s-1 e A/V de 4,9 g/m³, apresentou as maiores frações de remoção de cor e turbidez. / The present work aimed to study the influence of velocity gradient (Gzc) associated with the hydraulic detention time (tzc) and the rate of surface application (TASzc) in the contact zone in the efficiency of clarification of a unit rectangular dissolved air flotation pilot scale, treating water supplies. Two different kinds of configurations of the reactor dissolved air flotation in pilot scale (UPFA) (A and B) were studied, which differ in the length of the contact zone - A (90 mm) and B (140 mm). The TASzc - A (133 ± 3 m/h) and B (86 ± 1 m/h) - and tzc - A (54 ± 1 s) and B (84 ± 1 s) were different. Three different values of Gzc were analysed - A (1.8, 6.5, 10.2 s-1) and B (0.9, 4.7, 6.3 s-1) by insertion of grilles with different characteristics within the zone contact. And for each value of Gzc, three values of A/V (3.73, 4.90, 6.41 g/m³) were investigated. In all trials, the following parameters were set: flow of synthetic raw water (5.4 m³/h), synthetic raw water temperature (26 ± 1ºC), coagulation pH (6.5 ± 0.1); flocculation time (17.2 minutes), the speed gradient flocculation (110 s-1); flow disposal after flocculation (0.8 m³/h), input flow to the flotation (Qe) (4, 6 m³/h), input speed for flotation (ve) (180 m/h), cross-flow velocity (45 m/h), TASzs (14.6 ± 0.2 m/h), saturation pressure (4.5 ± 0.1 kgf/cm ²). The pilot plant was fed with synthetic water, which showed turbidity of approximately 7.4 ± 0.6 NTU, and apparent color, about 39.4 ± 4.3 HU. The removal efficiency of the analyzed parameters for each Gzc is less sensitive to variations in the A/V in the configuration A than in the configuration B. In configuration A, the grille that showed Gzc about 6.5 s-1 gave better results for each A/V analysis. In configuration B, the grille that has generated Gzc around 4.7 s-1 provided the best removal efficiency of turbidity and color for each A/V studied. Furthermore, in the configuration B, the removal efficiency of color and turbidity was less sensitive to variations in A/V for Gzc 4.7 s-1 than for other values of Gzc. The grille that generated the best results in the configuration A was the same for the configuration B. Therefore the use of that grille favored the performance of configurations A and B. Comparing all the situations studied in two configurations, the test with the configuration A (with tzc the 54 s) with Gzc of 6.3 s-1 and A/V of 4.9 g/m³, had the highest removal efficiencies of color and turbidity.

The diploma thesis deals with micro-fuels in drinking water sources and their subsequent removal. In the thesis mainly pesticides and pharmaceuticals are described. The reader is first introduced to the most common pesticides occurring in water and their consumption. Drugs are described in a similar context. In addition, there are practical studies on the occurrence, degradation and removal of micro-pollutants from water. The final thesis is a laboratory experiment dealing with the removal of salicylic acid from water by filtration through the filtration material Bayoxide E33 and activated carbon. The thesis describes the procedure and results of the experiment.

The master's thesis deals with actual possibilities of acquisition water from air humidity in order to obtain fresh water, focusing on energy intensity of vapor-compression refrigeration for it is production. There is a basic determine study for Czech climatic zone in selected localities. For graded cooling capacity dependencies describing the acquisition of water from the air, where is the energy intensity ranges on average between 0,3 ÷ 0,5 kWh/l. For the selected family house are set the individual variants of non-potable rainwater management.

Der Gegenstand dieser Arbeit ist eine neue Optimierungsmethode zur Minimierung der Produktkosten von Kraftwerksprozessen ohne und mit nachgeschalteten Anwendungen. Diese Methode, die Planern und Projektanten als Werkzeug zur Auslegung von Kraftwerken dienen soll, wird erläutert und exemplarisch zur Optimierung eines ausgewählten Gas- und Dampfturbinenkraftwerkes verwendet. Im Rahmen der Untersuchungen werden dabei zwei Varianten betrachtet: Der Kraftwerksentwurf/-betrieb ohne und mit Auskopplung von Energie- und Stoffströmen. Beim Kraftwerksentwurf/-betrieb mit Auskopplung von Energie- und Stoffströmen wird das Gas- und Dampfturbinenkraftwerk mit einer nachgeschalteten hybriden Meerwasserentsalzungsanlage verknüpft. Zur Identifizierung der jeweils zu optimierenden Komponenten/Parameter werden bei der neuen Methode Elemente der thermo- bzw. exergoökonomischen Analyse und der Sensitivitäts- und Trendlinienanalysen verwendet. Die Optimierung selbst folgt dem Koordinatenverfahren nach Gauß und Seidel. Anhand der Optimierungsergebnisse und der Kriterien ’Auswahl/Beitrag der Komponenten/Parameter’ sowie ’Rechenumfang’ wird die neue Optimierungsmethode mit bekannten thermo- bzw. exergoökonomischen Optimierungsmethoden (Quadranten-/Matrix-Methode, thermo-/exergoökonomische Kennzahlen-Methode) verglichen und bewertet. Zur Ergebnisdiskussion werden Parameterstudien erstellt. Abschließend werden Empfehlungen zur Gestaltung des untersuchten Gas- und Dampfturbinenkraftwerkes gegeben und Ansätze für weiterführende Forschungsarbeiten in der Kraftwerkstechnik abgeleitet.

Norrvatten is a municipal association which owns a water treatment plant capable of supplying good quality drinking water to the consumers in the associated neighbouring municipalities. After preliminary investigations for the future year of 2050, there were estimates which suggest a potential water quality degradation in the lake which supplies the raw water for treatment due to uncertain future climatic conditions and other forms of pollutions from the surrounding. There is also a forecast of future population increase in the respective neighbouring municipalities of Stockholm county, which consequently increases the demand for additional quantity of supplied drinking water. The supplied drinking water, which even though is currently acceptable by the standards set by Swedish Food Agency, still requires additional advanced treatment techniques in order to provide an upscale to its quality. This increase in water quality can be achieved by increasing the natural organic matter removal treatment techniques in the water treatment plant by implementing more chemical and microbiological barriers. Norrvatten has proposed several alternative water purification methods, out of which one of them can be implemented in the water treatment plant, after an expansion in the capacity of the plant to achieve all the above-mentioned requirements.  A case study has been performed at Norrvatten in Stockholm, Sweden for evaluating the environmental performance of the proposed treatment alternatives. This study adopts a cradle-to-gate life cycle assessment methodology to analyze the alternatives using stand-alone and comparative assessment methods. An explicit focus is given with the selection of 15 different environmental categories to assess the related environmental burdens. The various hotspots identified from the analysis is investigated and identified to find the associated trade-offs with the alternatives under study. Additional parameter changes have been made in the alternatives to apprehend how the impacts change accordingly.  The various hotspots identified from the results of the study were, the utilization of granular activated carbons for filtration, the consumption of aluminium sulphate for coagulation, the consumption of soda if iron chloride is selected as the main coagulant, the consumption of electricity in the WTP by nanofiltration process, hydropower from pumped storage and the use of heavy trucks for transporting chemicals from suppliers to the site. Other aspects and assumptions from conducting a sensitivity analysis indicated that there are possibilities to decrease the impacts through the following changes. By switching the main coagulant from aluminium sulphate to iron chloride to decrease the major resource depletion and human health impacts with a trade-off increase in impacts from an increased production of soda for chemical consumption. By switching the current purchase of electricity, from a green energy mix to the Swedish grid mix, to greatly improve the environmental performance of the treatment plant. This energy change was observed to result in the reduction of global warming potential from CO2 emissions. Other changes which can be implemented to reduce the overall environmental impacts are switching from fuel- based transportation trucks to electric trucks and switching chemical suppliers from outside Sweden to suppliers located near or within Sweden, closer to the water treatment plant. / Norrvatten är en kommunförening som äger en vattenreningsanläggning som kan leverera dricksvatten av god kvalitet till konsumenterna i de angränsande grannkommunerna. Efter preliminära undersökningar för det kommande året 2050 fanns det uppskattningar som tyder på en potentiell nedbrytning av vattenkvaliteten i sjön som ger råvattnet för behandling på grund av osäkra framtida klimatförhållanden och andra former av föroreningar från omgivningen. Det finns också en prognos om framtida befolkningsökning i respektive grannkommuner i Stockholms län, vilket följaktligen ökar efterfrågan på ytterligare mängd levererat dricksvatten. För närvarande levererat Dricksvatten, som trots att det är acceptabelt enligt de standarder som fastställts av Livsmedelsverket, kräver ytterligare avancerade behandlingstekniker för att ge en förbättring av dess kvalitet. Denna ökning av vattenkvaliteten kan uppnås genom att öka de tekniska behandlingsteknikerna för avlägsnande av organiskt material i vattenreningsverket genom att implementera fler kemiska och mikrobiologiska barriärer. Norrvatten har föreslagit flera alternativa vattenreningsmetoder, varav en av dem kan implementeras i vattenreningsverket, efter en utvidgning av anläggningens kapacitet att uppnå alla ovannämnda krav.  En fallstudie har utförts vid Norrvatten i Stockholm för att utvärdera miljöprestanda för de föreslagna behandlingsalternativen. Denna studie använder livscykelanalys för att analysera alternativen. Ett uttryckligt fokus ges med valet av 15 olika miljökategorier för att bedöma relaterade miljöbördor. De olika hotspots som identifierats från analysen undersöks och identifieras för att hitta tillhörande avvägningar med alternativen som studeras. Ytterligare parameterändringar har gjorts i alternativen för att förstå hur effekterna förändras i enlighet därmed.  De olika hotspots som identifierats från resultaten av studien var användningen av grandulerat aktivt kol för filtrering, konsumtionen av aluminiumsulfat för koagulering, konsumtionen av läsk om järnklorid väljs som huvudkoaguleringsmedel, förbrukningen av el i vattenreningsverket genom nanofiltreringsprocessen , vattenkraft från pumplagring och användning av tunga lastbilar för transport av kemikalier från leverantörer till anläggningen. Andra aspekter och antaganden från att genomföra en känslighetsanalys visade att det finns möjligheter att minska effekterna genom följande förändringar. Genom att byta huvudkoaguleringsmedlet från aluminiumsulfat till järnklorid för att minska den största resursutarmningen och människors hälsoeffekter med en avvägning av effekterna från en ökad produktion av natriumkarbonat. Genom att byta det aktuella inköpet av el, från en grön energimix till den svenska nätmixen, för att kraftigt förbättra reningsverkets miljöprestanda. Denna energiförändring observerades leda till en minskning av den globala uppvärmningspotentialen från koldioxidutsläpp. Andra förändringar som kan genomföras för att minska den totala miljöpåverkan är att byta från bränslebaserade transportbilar till elektriska lastbilar och byta kemikalieleverantörer från utanför Sverige till leverantörer nära eller inom Sverige, närmare vattenreningen växt.

Climate change and increasing population demands expansion of infrastructures in urban areas. Drinking water treatment plants are part of the critical infrastructure and must upgrade in the future. However, expansions and technological advancements often come with impacts on the environment. Therefore, this thesis compares two drinking water treatment technologies regarding its environmental impacts through a life cycle assessment. In specific, the thesis elaborates the impacts of membrane precipitation and conventional precipitation in the suspended solids removal stage at a treatment plant in Piteå, Sweden. The research addresses the environmental challenges posed by traditional and modern water treatment methods, providing insights and knowledge to more sustainable water practices. The research involves an attributional, comparative life cycle assessment. The findings from this thesis intend to guide decision-making for future drinking water treatment plant designs.  The research was conducted through an attributional and comparative LCA using SimaPro software based on ISO 14040-series standards. This approach allowed for a detailed analysis of both the operational and construction phases of the treatment technologies, considering various environmental impact categories.  The results indicate that membrane system presents for most impact categories, a lower  environmental impact in the combined configuration scenario. The combined configuration scenario includes for the membrane system calcium carbonate, aluminium sulfate and 95% reduced hypochlorite consumption. The conventional system considers in the combined configuration scenario aluminum sulfate and calcium carbonate This is primarily due to its efficiency in reducing chemical usage such as coagulants. However, if both systems use the same chemical composition (same coagulant, pH-controlling chemicals as in the base scenario), the conventional system becomes more environmentally friendly than the membrane system in most impact categories. This is mainly due to the additional CEB chemical consumption of the membrane system, which nullifies the advantage of lower consumed coagulants. Compared to the operational phase in both systems, the construction phase is insignificant over the lifetime of the treatment plants. The major hotspots are identified as operational chemicals and chemical enhanced backwash chemicals, which are used for the membrane system only. Scenario analysis shows that chlorine/aluminum-based chemicals such as polyaluminum chloride and hypochlorite have a high environmental impact and with reducing or even changing these chemicals major improvements can be achieved. Especially changing aluminum-based chemicals to iron-based chemicals show a significant decrease of impacts in all categories. Further, the scenario analysis shows that by changing lime to calcium carbonate, the environmental impacts can be reduced significantly. Therefore, the future focus should rely on reducing and changing chemicals, especially switching aluminum/chlorine based to iron-based chemicals. / Klimatförändringarna och den ökande befolkningen kräver utbyggnad av infrastrukturen i stadsområden. Reningsverk för dricksvatten är en del av den kritiska infrastrukturen och måste uppgraderas i framtiden. Expansioner och tekniska framsteg medför dock ofta påverkan på miljön. Detta examensarbete jämförs därför två tekniker för dricksvattenberedning med avseende på miljöpåverkan genom en grundlig livscykelanalys. Mer specifikt behandlar avhandlingen effekterna av membranfiltrering och konventionell fällning i steget för avlägsnande av suspenderade ämnen vid ett reningsverk i Piteå, Sverige. Forskningen tar upp de miljömässiga utmaningar som traditionella och moderna vattenbehandlingsmetoder innebär och ger insikter och kunskap om mer hållbara vattenmetoder. Resultaten från denna avhandling är avsedda att vägleda beslutsfattandet för framtida utformningar av dricksvattenreningsverk och erbjuder ett första verktyg för mer hållbara vattenbehandlingsmetoder.  Forskningen genomfördes genom en bokförande och jämförande LCA med hjälp av programvaran SimaPro baserat på ISO 14040-seriens standarder. Detta tillvägagångssätt möjliggjorde en detaljerad analys av både drifts- och konstruktionsfaserna för behandlingsteknikerna, med beaktande av olika miljöpåverkanskategorier.  Resultaten tydar på att membranfiltrering ger en lägre total miljöpåverkan vid vanliga förhållanden. Detta beror främst på dess effektivitet när det gäller att minska kemikalieanvändningen, t.ex. koaguleringsmedel. Men om båda systemen använder samma kemiska sammansättning (samma koaguleringsmedel) är det konventionella systemet mer miljövänligt än det konventionella systemet. Detta beror främst på den extra kemikalieförbrukningen för CEB i membransystemet, vilket upphäver fördelen med lägre förbrukning av koaguleringsmedel. Jämfört med driftsfasen i båda systemen är byggfasen obetydlig under reningsverkens livstid. De viktigaste aspekterna identifieras som driftskemikalier och kemikalier för kemiskt förstärkt backspolning, som endast används för membransystemet. Scenarioanalysen visar att klor-/aluminiumbaserade kemikalier som polyaluminiumklorid och hypoklorit har en hög miljöpåverkan och att stora förbättringar kan uppnås genom att minska eller till och med byta ut dessa kemikalier. Särskilt om aluminiumbaserade kemikalier byts ut mot järnbaserade kemikalier minskar påverkan betydligt i alla kategorier. Vidare visar scenarioanalysen att miljöpåverkan kan minskas betydligt genom att byta ut kalk mot kalciumkarbonat. Därför bör fokus i framtiden ligga på att minska och byta ut kemikalier, särskilt att byta ut aluminium/klorbaserade kemikalier mot järnbaserade kemikalier.

Stormwater runoff has negative impacts on water resources, human health and environment. In this research the effectiveness of Rain Water Harvesting (RWH) systems is examined as a stormwater Best Management Practice (BMP). Time-based, evapotranspiration-based, and soil moisture-based irrigation scheduling methods in conjunction with RWH and a control site without RWH were simulated to determine the effect of RWH as a BMP on a single-family residence scale. The effects of each irrigation scheduling method on minimizing water runoff leaving the plots and potable water input for irrigation were compared. The scenario that reflects urban development was simulated and compared to other RWH-irrigation scheduling systems by a control treatment without a RWH component. Four soil types (sand, sandy loam, loamy sand, silty clay) and four cistern sizes (208L, 416L, 624L, 833L) were evaluated in the urban development scenario. To achieve the purpose of this study; a model was developed to simulate daily water balance for the three treatments. Irrigation volumes and water runoff were compared for four soil types and four cistern sizes. Comparisons between total volumes of water runoff were estimated by utilizing different soil types, while comparisons between total potable water used for irrigation were estimated by utilizing different irrigation scheduling methods. This research showed that both Curve Number method and Mass-Balance method resulted in the greatest volumes of water runoff predicted for Silty Clay soil and the least volumes of water runoff predicted for Sand soil. Moreover, increasing cistern sizes resulted in reducing total water runoff and potable water used for irrigation, although not at a statistically significant level. Control treatment that does not utilize a cistern had the greatest volumes of predicted supplemental water among all soil types utilized, while Soil Moisture-based treatment on average had the least volume of predicted supplemental water.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Intensive strip and leach mining activity within a confined region usually causes environmental impacts both on the land and on water quality. Adverse water quality effects could be realized long after any mining activity has ceased due to the continuous leaching by precipitation of contaminants from spoils piles and leach dumps. The Miami, Arizona region is unique in its surface and subsurface hydrology. Two unconnected aquifers underlay the region with both serving as domestic (private and municipal) and industrial (mining) supply sources. The shallow floodplain alluvial aquifer is hydraulically connected to surface drainage from mine tailings and leach dumps. Several wells drawing from this aquifer have been abandoned as a municipal supply source due to severe water quality degradation. Water quality in these wells varies directly with precipitation indicating a correlation between surface drainage over and through tailings and leach piles. Expansion of spoils dumps into natural recharge pathways of the deeper Gila Conglomerate aquifer has raised concern that this aquifer may also be subjected to a long term influx of mine pollutants. Questions have also been raised concerning the potential effects of a proposed in situ leaching operation on the water quality of the conglomerate aquifer.

Phytoplankton blooms compromise the quality of freshwater ecosystems and the efficient processing of water by treatment works worldwide. This research aims to determine whether in-situ filamentous biofiltration processes mediated by living roots and synthetic filters as media can reduce or remove the phytoplankton loading (micro-algae and cyanobacteria) prior to a potable water treatment works intake. The underlying biofiltration mechanisms were investigated using field and laboratory studies. A novel macroscale biofilter with three plant species, named the "Living-Filter", installed in Farmoor II reservoir, UK, was surveyed weekly for physicochemical and biological variables under continuous flow conditions during 17 weeks. The efficiency of a mesoscale biofilter using the aquatic plant Phalaris arundinacea and synthetic filters, was tested with Microcystis aeruginosa under continuous flow conditions and in batch experiments. The 'simultaneous allelochemical method' was developed for quantifying allelochemicals from Phalaris in aqueous samples. Microscale studies were used to investigate biofilter allelochemical release in response to environmental stressors and Microcystis growth inhibition in filtered and unfiltered aqueous root exudate. Results demonstrate that the removal of phytoplankton biomass by physical mechanisms has a removal efficiency of ≤45% in the "Living-Filter" (filamentous biofilter plus synthetic fabric) and that the removal of Microcystis biomass using only biofilters was 25%. Chemical mechanisms that reduce Microcystis cell numbers are mediated by allelochemicals released from biofilter roots. Root exudate treatments on Microcystis revealed that Microcystis growth is inhibited by allelochemicals, not by nutrient competition, and that protists and invertebrates play a role in removing Microcystis. Filamentous biofilters can remove phytoplankton biomass by physical, chemical and biological mechanisms. Biofilters and synthetic filters in combination improve removal efficiency. Application of macroscale biofilters prior to potable water treatment works benefits the ecosystem. Plant properties, biofilter size to surface water ratio, and retention time must be considered to maximise the benefits of biofiltration processes.