The use of sunlight for water disinfection has been practiced since ancient times. Only in the last three decades has solar disinfection become widely recognized as a viable means of providing safe drinking water to the disadvantaged portion of the world’s population. The World Health Organization estimates that 1.6 million people die every year because of waterborne diseases. <br/><br/> The Swiss Federal Institute of Environmental Science and Technology and their Department of Water and Sanitation in Developing Countries have been instrumental in propagating the solar water disinfection (SODIS) process in developing countries. The reason for this technology being widely used and accepted is its ease of use and effectiveness: water is placed in clear plastic bottles and exposed to direct sunlight for approximately six hours. The microorganisms in the water absorb the sunlight and it, in turn at sufficient UV dosages, causes mutations to their genetic material, inhibiting reproduction. Although some pathogens may still be viable they are no longer infective. The result is microbiologically safe water. <br/><br/> Research to date has explored everything from which colour and size the SODIS containers should be to whether adding catalysts to the water before exposure improves disinfection. Apart from a few studies that examined the effect of shaking the bottles (to entrain air) before exposure, there has been limited research on pretreatments for enhancing solar disinfection. <br/><br/> The focus of this project was to explore two pretreatments for SODIS and determine how they affect the efficiency of the process. The first stage was to examine one of the currently used pretreatments: cleaning the water containers before use. The second stage was to develop an accessible, low-cost filtration technique to remove particles from the water before exposure to sunlight. Particles in the water disperse the light and protect the microorganisms from being inactivated, so it is important to have as few particles as possible; the recommended upper limit is 30 NTU for solar disinfection. In many instances, surface water with high turbidity (greater than 200 NTU) serves as the only source for drinking water in developing areas. <br/><br/> The first series of experiments in the current research evaluated if cleaning the bottles was necessary and if so, which cleaning agents would be most effective and available. The agents selected were 70% isopropyl alcohol, a soap-water mixture, and lime juice. The experiments demonstrated that cleaning with 70% isopropyl alcohol did not affect the process in any way. Cleaning with the soap-water mixture did have a slightly negative effect on the process; there was substantial microbial recovery when bottles were kept in the dark overnight. In the case of the lime juice, it actually inhibited the disinfection process. It is necessary to remove any debris that might exist within the containers before using them, but using a chemical cleaning agent or mechanically scrubbing can decrease the amount of disinfection that occurs during SODIS. Thus, it is suggested that using a chemical pretreatment is not necessary and has the potential to inhibit disinfection, especially without proper training or technical knowledge. <br/><br/> The second series of experiments identified the optimal design for a low-cost roughing filter that could be used to remove particles from water before exposure to sunlight. The roughing filter that was built from the same plastic pop bottles used for solar disinfection, as well as gravel and sand. It was constructed with three centimetres of gravel on the bottom of the pop bottle and then 17 cm of coarse sand was added on top to make the total filter height 20 cm. A 0.6 mm hole was made at approximately 1.5 cm from the bottom of the bottle using a standard sewing needle. Each filter run consisted of 10 L of water at approximately 200 NTU. Experimental results indicated that 95% removal of turbidity could be achieved. These roughing filters can be constructed from readily available and affordable materials in developing countries and produce an effluent water quality of less than 30 NTU when initial turbidities are greater than 200 NTU. <br/><br/> Finally, the third series of experiments focused on testing the newly developed roughing filter in series with SODIS to evaluate the system as a whole. The results confirmed that using the roughing filter, as a pretreatment to SODIS, is a highly effective means of improving the disinfection potential of the process. These roughing filters produce an effluent water quality of less than 30 NTU, which is required for SODIS, making them a viable pretreatment for turbid water intended for SODIS use.

Syftet med examensarbetet var att undersöka effekterna av ozonering och filtrering på råvattnet från sjön Mälaren. Studien är utförd i en pilotanläggning på Lovö vattenverk, Stockholm Vatten AB, under våren 2004. En negativ effekt med den konventionella reningen är den stora konsumtionen av kemiska koagulanter. Kemikalieanvändningen leder till många transporter och processen producerar också ett slam som för närvarande transporteras till Mälaren. År 2001 byggdes en pilotanläggning på Lovö vattenverk för utveckling av nya processer, en av processerna är ozonering följt av olika filter. Ozonering har använts i Europa i många år som desinfektion i slutet av dricksvattenreningsprocessen. Intresset för ozonering har ökat markant sista åren och idag används ozonet också i andra steg i processen. Förutom desinfektion har ozonet andra fördelar, som oxidation av järn och magnesium, mikroflockning, reduktion av lukt och smak samt är bra på att reducera färgen på vattnet. Mikroflockningen leder till att kemikalieanvändningen kan minska och i vissa fall tas bort helt. Den här studien startade med en litteraturundersökning följd av försök med ozonering och filtrering i pilotanläggningen. De första undersökningarna sammanfattades med att ozonering följt av filtrering inte gav tillräckligt bra resultat och processen behöver ett komplement för att producera ett högklassigt vatten. Undersökningen fortsatte med laboratorieanalyser för att undersöka effekterna av olika kemiska koagulanter. Resultatet visade att järnsulfat tillsammans med kalcium var ett bra alternativ och en lägre kemikaliedos kunde användas. Efter implementering av kalcium och järnsulfat till pilotanläggningen testades olika ozondoser och olika järnsulfatdoser. Det bästa resultatet erhölls då man använde sig av en ozondos på 6 mg O3/l och en järnsulfatdos på 50-60 μmol/l. Denna mängd av järnsulfat är ca 60 % lägre än den dos som används vid den konventionella reningen på Lovö vattenverk. Olika filter används i pilotanläggningen och för att förbättra resultatet provades även ett Filtralite-filter som biofilter istället för GAC-filtret. Jämförelsen mellan Filtralite-filter och GAC-filter visade på stora skillnader i parametervärden i början av studietiden. När bakteriepopulationen ökade i Filtralite-filtret blev skillnaderna mindre och i slutet av undersökningstiden var parametervärdena likartade. Det slutliga resultatet indikerar att Filtralite-filter kan vara ett bra alternativ som biofilter. / This Master thesis was made to investigate the effects of ozonation and filtration on raw water from Lake Mälaren. The study was performed in lab-scale as well as in a pilot plant at Lovö waterworks, Stockholm Water Company during spring 2004. The conventional treatment at Lovö waterworks comes with a few disadvantages, such as large consumption of chemical coagulants. The chemical consumption leads to many transports and the treatment also produces a sludge which is, in present, returned to Lake Mälaren. In 2001 a pilot plant were built at Lovö waterworks for research on new treatment processes, and ozonation followed by filtration is one of them. Ozonation has been used in Europe for several years as disinfection at the end of the drinking water treatment process. The interests of ozonation has increased significantly in recent years and today the ozonation is used in other steps in the drinking water treatment process. Except for the disinfection, ozone has other benefits such as oxidation of iron and manganese, microflocculation, reduction of taste and odour and it is also effective to reduce the water colour. The microflocculation leads to the fact that less or no coagulants need to be used in the process. This study started with a literature overview followed by experiments on ozonation and filtration in the pilot plant. After the first experiments the conclusions were that the ozonation and filtration did not reach the same results as Lovö waterworks. To continue, jar tests were made to see the effects of different coagulants. The result indicated that ferric sulphate together with calcium addition (pH-adjustment) was a good alternative. Thereby a lower coagulant dose could be used. When ferric sulphate and calcium were implemented into the pilot plant, different ozone doses and ferric sulphate doses were tested. The best results occurred when an ozone dose of 6 mg O3/l and a ferric sulphate dose of 50-60 μmol/l were used. This amount of ferric sulphate is approximately 60 % lower than that for the conventional treatment at Lovö waterworks. To produce ozone electrons are needed and energy consumption increases with approximately 66 % compared to the conventional treatment. The decrease in chemical dose and increase in energy demand gives a decrease of the total cost with 10 % compared to the conventional treatment. The results indicate that the treatment with ozonation, calcium addition and ferric sulphate as a coagulant is an alternative to the conventional treatment. Different filters were used in the pilot plant and to improve the results a Filtralite-filter was tested instead of the GAC-filter as a bio filter. When comparing Filtralite-filter with the GAC-filter there were large differences between the filters at the beginning of the study. When the bacteria population in the Filtralite-filter had started to increase the differences became less. In the end of the experimental period the filters had similar conditions and Filtralite-filter may be a good alternative as a biofilter.

An excessive input of nutrients to lakes and other water bodies has created a problem with eutrophication in Sweden. Untreated, or partially treated, domestic sewage is a major source for discharge of phosphorus (P), which is the nutrient most frequently responsible for eutrophication of most fresh waters and the Baltic Sea. The waste water can be cleaned by filter materials, which have a high P-retention ability and which after saturation may be used as fertilizers. Four potentially suitable filter materials were tested in batch- and column experiments in this study. In the batch experiments, the following materials were shaken with waste water in time series ranging from 5 seconds to 60 minutes: coarse (1-4 mm) and fine (0-2 mm) Polonite® (heated bedrock from Poland); Filtralite® (light expanded clay aggregates with limestone added before burning); water cooled blast furnace slag (BF-slag) and BF-slag mixed with 10% burned limestone. In the column experiment, the phosphorus sorption capacity in BF-slag and BF-slag mixed with burned limestone was observed under saturated and unsaturated flow conditions for 10 weeks. The waste water used in both experiments originated from the full scale testing site at Ångersjön in Sweden. After the column experiment was ended, the filter materials were investigated with XRD (X-ray diffraction) and SEM (scanning electron microscope) in order to figure out which chemical reactions that had taken place. The results from the batch experiments show that fine Polonite® and BF-slag mixed with limestone have the fastest P sorption capacity. Already after 5 seconds of shaking the materials showed effective retention of P. The coarse Polonite®, Filtralite® and BF-slag showed similar sorption capacities, although the coarse Polonite® tended to be somewhat inferior. The column studies showed that the materials used in the columns had a sorption capacity of 98 % or more. The XRD and SEM indicated that an amorphous calcium-P-compound was created in the filter material. / I Sverige är reningen av fosfor i vatten från enskilda avlopp ofta bristfällig, vilket bland annat kan leda till övergödning av sjöar, hav och vattendrag. Sedan några år tillbaka har olika filtermaterial med speciella reaktiva egenskaper, som bland annat avskiljer fosfor från avloppsvatten, undersökts. Tanken med filtermaterialen är att de efter mättnad med näringsämnen ska kunnas användas som jordförbättringsmedel. I denna rapport har några olika filtermaterial, lämpade för fosforavskiljning, undersökts genom skak- och kolonnförsök. I skakförsök, där skaktiderna varierade mellan 5 sekunder och 60 minuter, testades Polonite®, Filtralite®, Hyttsand och Hyttsand blandad med 10 % bränd kalk. Polonite® är en upphettad form av bergarten opoka varav två olika kornstorleksfraktioner (0-2 mm och 1-4 mm) användes. Filtralite® och Hyttsand är antropogena filtermaterial. Filtralite® tillverkas i Norge och består av kalkhaltiga kulor av expanderad lera (Leca®). Hyttsand framställs genom vattenkylning av masugnsslagg som bildas vid framställningen av råjärn vid stålverket i Oxelösund. I kolonnförsöken, som utfördes under 10 veckor, studerades Hyttsand och Hyttsand blandad med 10 % bränd kalk under omättade och mättade flödesförhållanden. I samtliga experiment användes avloppsvatten från reningsverket vid Ångersjön, där Filtralite® och Hyttsand testas i fullskala. Efter kolonnförsöken avslutats undersöktes filtermaterialen med XRD (röntgendiffraktion) och SEM (svepelektron mikroskop) för att utreda vilka mekanismer som medverkat vid avskiljningen av fosfor. Resultaten från skakförsöken visade att finkornig Polonite® och Hyttsand blandad med kalk avskiljer fosfor effektivt redan efter skakning i 5 sekunder. Grovkornig Polonite, ren Hyttsand och Filtralite® sorberade fosfor tämligen likartat, även om den grovkorniga Poloniten® tenderade att vara aningen sämre än de övriga. Resultaten från kolonnförsöken visade att fosfor kunde avskiljas till över 98 % i alla kolonner och att det bildats amorfa fosfatföreningar, främst med kalcium, under den 2,5 månader långa experimentperioden.

Resurseffektiv kvävereduktion genom nitritation Problematiken med övergödning i våra akvatiska system har lett till hårdare krav på kväverening vid våra reningsverk. En rejektvattenbehandling har visat sig vara ett bra alternativ för att utöka kvävereningen. Vid Nykvarnsverket i Linköping renas avloppsvatten och sedan 2009 finns en SHARON-anläggning i drift. SHARON står för ”Stable High rate Ammonia Removal Over Nitrite” och är en kvävereningsprocess för rejektvatten utvecklad av Grontmij i samarbete med Tekniska universitetet i Delft. I denna studie har SHARON-processen i Linköping undersökts. Dess funktion har utvärderats, drift- och underhållsbehov har studerats och nyckeltal för processen har tagits fram. Arbetet har utförts under våren 2012 genom teoretiska studier samt genom platsbesök och praktiska undersökningar vid Nykvarnsverket i Linköping. Resultaten av denna studie visar att SHARON-processen i Linköping renar ammonium med en reningsgrad på 92,5 %. Denna kväverening motsvarar 18 % av reningsverkets totala kvävereduktion trots att endast cirka 0,5 % av det totala flödet genom reningsverket behandlas. Kostnaden för den utökade kvävereningen är 9,3 kr/kg N och energiåtgången är 2,2 kWh/kg N. Processen har sedan idrifttagandet haft undermålig luftningskapacitet. Detta har troligen lett till den instabilitet som processen uppvisat och att den uppsatta reningsgraden på 97 % inte nås. På grund av låga syrehalter finns Anammoxbakterier i SHARON-reaktorn. Anammoxbakterierna påverkar kvävereningen, men i vilken utsträckning detta sker är inte klarlagt. En ny blåsmaskin är i drift sedan den 30 april och luftningskapaciteten motsvarar nu ursprunglig processdesign. Effekten av den utökade luftningen behöver utvärderas ytterligare. De stöddoseringar av bland annat fosfor och koppar, som är nödvändiga för mikroorganismernas tillväxt, kan exempelvis behöva justeras då processen reagerat på den utökade syretillförseln. / Resource-efficient nitrogen removal through nitritation Eutrophication in our aquatic systems has led to stricter limits regarding nitrogen removal at our wastewater treatment plants. Side stream treatment of reject water has proven to be a good alternative for extended nitrogen removal. At Nykvarnsverket, in Linköping municipality, in Sweden a SHARON-process has been operational since 2009. SHARON stands for ”Stable High rate Ammonia Removal Over Nitrite” and is a nitrogen removal reject water treatment process developed by Grontmij and Delft University of Technology. In this study the function of the SHARON-process in Linköping has been evaluated. The operating and maintenance costs have been calculated. The study has been performed during the spring of 2012 through theoretical studies and practical investigations at Nykvarnsverket in Linköping. The results show that the SHARON-process in Linköping removes ammonia with an efficiency of 92.5 %. This nitrogen removal corresponds to 18 % of the total nitrogen removal at Nykvarnsverket, in spite of the fact that the reject water treatment constitutes only 0.5 % of the treatment plant’s total hydraulic capacity. The cost of the extended nitrogen removal was 9.3 SEK/kg N and the energy consumption was 2.2 kWh/kg N. Ever since the process was put into operation, there has been a lack of aeration capacity. This is probably the cause of the process instability and the fact that the nitrogen removal efficiency does not reach the design value of 97 %. Because of the low levels of dissolved oxygen there are Anammox-bacteria present in the process. The Anammox-bacteria affect the nitrogen removal, but exactly to what extent has not been determined. A new blower is in operation since the 30th of April and the aeration capacity now corresponds to the original design. The effect of the increased aeration needs further evaluation. The aid dosages of copper and phosphorous, important for the growth of the microorganisms, may need to be fine-tuned when the process has reacted to the increased oxygen supply.

For produced biogas to be usable as vehicle fuel it has to be upgraded to a higher energy content. This is accomplished by elevation of the methane concentration through removal of carbon dioxide. Absorption with water wash is the most common upgrading method used in Sweden today. The upgrading technique is based on the fact that carbon dioxide is more soluble in water than methane. Upgrading plants that utilises this method have problems with microbial growth in the system. This growth eventually leads to a stop in operation due to the gradually drop in upgrading capacity. The aim of this thesis were to evaluate the possibility to through some kind of water treatment maintain an acceptable level of growth or altogether prevent it in order to maintain an acceptable process capacity and thereby avoid the need to clean. Through collection of literature the implementation possibilities were evaluated with regard to efficiency, economic sustainability and if there would be a release of any harmful substances. In order to prevent the microbial growth in the columns the treatment should either focus on removing microorganisms or limit the accessible nutrients. For the single pass system it is concluded that the treatment should reduce the biofilm formation and be employed in an intermittent way. Among the evaluated treatments focusing on the reduction of microorganisms the addition of peracetic acid seems to be the most promising one. For the regenerating system the treatment method could focus on either one. As for the single pass system peracetic acid could be added to reduce the amount of microorganism. To reduce the amount of organic matter an advanced oxidation process could be deployed with the advantage that it also could remove the microorganisms. / För att kunna använda den producerade biogasen som fordonsgas måste dess energiinnehåll höjas. Detta åstadkoms genom avskiljning av koldioxid så att metankoncentrationen ökar. Den vanligaste förekommande uppgraderingstekniken i Sveriges är absorption med vatten, som bygger på att koldioxid är mer lösligt än metan i vatten under tryck. Uppgraderingsanläggningarna har mikrobiell tillväxt på fyllkropparna i absorptionskolonnen, vilket ofrånkommligen orsakar en lägre uppgraderingskapacitet och slutligen är ett stopp i produktionen nödvändig för kunna tvätta fyllkropparna. Anläggningarna som recirkulerar processvattnet kan även ha tillväxt i kolonnen, där den lösta koldioxiden tas bort. Syftet med detta arbete var att genom en litteraturstudie undersöka om det vore möjligt att undvika eller åtminstone hålla tillväxten under en acceptabel nivå genom någon typ av vattenrening. De olika reningsmetoderna utvärderades med avseende på möjlighet att implementeras i det befintliga uppgraderings systemet, effektivitet, möjliga utsläpp och ekonomisk hållbarhet. För att begränsa tillväxt i kolonnerna ska vattenreningen antingen fokusera på att ta bort mikroorganismer eller begränsa tillgången på näringsämnen för bakterierna som når kolonnerna via biogasen, luften som används för att ta bort koldioxiden från vattnet, eller via vattnet. För uppgraderingsanläggningar där processvattnet bara passerar kolonnen en gång rekommenderas en reningsmetod som fokuserar på reducera bildandet av biofilmen. Av de utvärderade metoderna ter sig perättiksyra som det bästa alternativet. För system med recirkulerande processvatten skulle reningsmetoden fokusera på antingen reduktion av mikroorganismer, organiskt material eller både och. Som för anläggningar med icke-cirkulerande vatten verkar perättiksyra vara det bästa alternativet för reduktion av mikroorganismer. En avancerad oxidationsprocess skulle kunna användas för att reducera mängden mikroorganismer och organiskt material.

A series of pilot-scale granular media filtration experiments was conducted to examine the effect of media roughness on filter performance and to evaluate the applicability of spherical, rough engineered ceramic filter media for use in granular media filters used for drinking water treatment. Filter media performance was assessed using turbidity and particle count reductions, Cryptosporidium oocyst and oocyst-sized microsphere removal, head loss and stability of operation. Experiments were designed to allow related facets of current filtration research to be examined. These included: effect of loading rate, coagulant type and dosage, and suitability of latex microspheres as surrogates for Cryptosporidium oocyst removal by granular media filtration. This study indicated that increased filter media roughness consistently improved turbidity and particle count reduction under the conditions investigated. As well, the engineered media also consistently achieved greater stability of operation during non-ideal operational periods (e.g. sudden change in filter influent turbidity).Oocyst removals were generally improved by media roughness, though this improvement was reliant on operating conditions, such as coagulant dose and type of coagulant used. The surrogate relationship between oocyst-sized latex microspheres and oocyst removal by filtration was also dependent on coagulant dose and type of coagulant. During trials with no coagulant addition, contrasts in oocyst removal were not significant, suggesting that neither surface roughness nor the size of media used were significant factors impacting oocyst removal by filtration during those periods of impaired operation. When pre-treating raw water with PACl, the engineered ceramic media achieved up to 1.25 log10 higher oocyst removals than conventional media. This improvement in oocyst removal relative to conventional media was not observed when alum was used as the primary coagulant, however. Future studies should directly compare engineered and conventional media filtration performance, using other raw water sources and different operating conditions. Biologically active filtration should also be included in future performance studies because the rough, highly porous surface of the engineered ceramic media is likely to provide excellent biofilm support.

The use of sunlight for water disinfection has been practiced since ancient times. Only in the last three decades has solar disinfection become widely recognized as a viable means of providing safe drinking water to the disadvantaged portion of the world’s population. The World Health Organization estimates that 1.6 million people die every year because of waterborne diseases. <br/><br/> The Swiss Federal Institute of Environmental Science and Technology and their Department of Water and Sanitation in Developing Countries have been instrumental in propagating the solar water disinfection (SODIS) process in developing countries. The reason for this technology being widely used and accepted is its ease of use and effectiveness: water is placed in clear plastic bottles and exposed to direct sunlight for approximately six hours. The microorganisms in the water absorb the sunlight and it, in turn at sufficient UV dosages, causes mutations to their genetic material, inhibiting reproduction. Although some pathogens may still be viable they are no longer infective. The result is microbiologically safe water. <br/><br/> Research to date has explored everything from which colour and size the SODIS containers should be to whether adding catalysts to the water before exposure improves disinfection. Apart from a few studies that examined the effect of shaking the bottles (to entrain air) before exposure, there has been limited research on pretreatments for enhancing solar disinfection. <br/><br/> The focus of this project was to explore two pretreatments for SODIS and determine how they affect the efficiency of the process. The first stage was to examine one of the currently used pretreatments: cleaning the water containers before use. The second stage was to develop an accessible, low-cost filtration technique to remove particles from the water before exposure to sunlight. Particles in the water disperse the light and protect the microorganisms from being inactivated, so it is important to have as few particles as possible; the recommended upper limit is 30 NTU for solar disinfection. In many instances, surface water with high turbidity (greater than 200 NTU) serves as the only source for drinking water in developing areas. <br/><br/> The first series of experiments in the current research evaluated if cleaning the bottles was necessary and if so, which cleaning agents would be most effective and available. The agents selected were 70% isopropyl alcohol, a soap-water mixture, and lime juice. The experiments demonstrated that cleaning with 70% isopropyl alcohol did not affect the process in any way. Cleaning with the soap-water mixture did have a slightly negative effect on the process; there was substantial microbial recovery when bottles were kept in the dark overnight. In the case of the lime juice, it actually inhibited the disinfection process. It is necessary to remove any debris that might exist within the containers before using them, but using a chemical cleaning agent or mechanically scrubbing can decrease the amount of disinfection that occurs during SODIS. Thus, it is suggested that using a chemical pretreatment is not necessary and has the potential to inhibit disinfection, especially without proper training or technical knowledge. <br/><br/> The second series of experiments identified the optimal design for a low-cost roughing filter that could be used to remove particles from water before exposure to sunlight. The roughing filter that was built from the same plastic pop bottles used for solar disinfection, as well as gravel and sand. It was constructed with three centimetres of gravel on the bottom of the pop bottle and then 17 cm of coarse sand was added on top to make the total filter height 20 cm. A 0.6 mm hole was made at approximately 1.5 cm from the bottom of the bottle using a standard sewing needle. Each filter run consisted of 10 L of water at approximately 200 NTU. Experimental results indicated that 95% removal of turbidity could be achieved. These roughing filters can be constructed from readily available and affordable materials in developing countries and produce an effluent water quality of less than 30 NTU when initial turbidities are greater than 200 NTU. <br/><br/> Finally, the third series of experiments focused on testing the newly developed roughing filter in series with SODIS to evaluate the system as a whole. The results confirmed that using the roughing filter, as a pretreatment to SODIS, is a highly effective means of improving the disinfection potential of the process. These roughing filters produce an effluent water quality of less than 30 NTU, which is required for SODIS, making them a viable pretreatment for turbid water intended for SODIS use.

Parameters associated with the detection and quantification of microorganisms (or discrete particles) in water such as the analytical recovery of an enumeration method, the concentration of the microorganisms or particles in the water, the log-reduction achieved using a treatment process, and the sensitivity of a detection method cannot be measured exactly. There are unavoidable random errors in the enumeration process that make estimates of these parameters imprecise and possibly also inaccurate. For example, the number of microorganisms observed divided by the volume of water analyzed is commonly used as an estimate of concentration, but there are random errors in sample collection and sample processing that make these estimates imprecise. Moreover, this estimate is inaccurate if poor analytical recovery results in observation of a different number of microorganisms than what was actually present in the sample. In this thesis, a statistical framework (using probabilistic modelling and Bayes’ theorem) is developed to enable appropriate analysis of microorganism concentration estimates given information about analytical recovery and knowledge of how various random errors in the enumeration process affect count data. Similar models are developed to enable analysis of recovery data given information about the seed dose. This statistical framework is used to address several problems: (1) estimation of parameters that describe random sample-to-sample variability in the analytical recovery of an enumeration method, (2) estimation of concentration, and quantification of the uncertainty therein, from single or replicate data (which may include non-detect samples), (3) estimation of the log-reduction of a treatment process (and the uncertainty therein) from pre- and post-treatment concentration estimates, (4) quantification of random concentration variability over time, and (5) estimation of the sensitivity of enumeration processes given knowledge about analytical recovery. The developed models are also used to investigate alternative strategies that may enable collection of more precise data. The concepts presented in this thesis are used to enhance analysis of pathogen concentration data in Quantitative Microbial Risk Assessment so that computed risk estimates are more predictive. Drinking water research and prudent management of treatment systems depend upon collection of reliable data and appropriate interpretation of the data that are available.

Point-of-use (POU) and point-of-entry (POE) water treatment are forms of decentralized water treatment that are becoming increasingly sought alternatives for ensuring the safety of drinking water. Although the acceptance of POU and POE systems is still the subject of some debate, it is generally acknowledged that they have a role to play in drinking water treatment. However, some of the main drivers for the increase in the use of POU and POE alternatives include: (1) the emergence of new technologies with high removal efficiencies of target contaminants; (2) the enhanced certification system of POU and POE treatment devices and components which ensures that devices have been well engineered to achieve defined contaminant removal targets and do not add contaminants from materials of construction; (3) the inclusion of POU and POE systems as acceptable means to comply with drinking water standards; and (4) the concerns voiced by consumers in several surveys regarding the safety of centrally treated drinking water; which, regardless of whether or not these concerns are justified, have led to an increase in the use of POU and POE treatment systems. With the commercialization of these devices the task of selecting a suitable device for treatment has become cumbersome. When the inherent complexity of a particular drinking water treatment task is added to the mix, a complex decision making situation is created. Thus the need for designing a decision support tool to compare and select POU and POE treatment systems was evident. Currently the best decision aid for selecting POU and POE systems is NSF International’s listing of the devices and their contaminant reduction claims. A significant contribution of this research is the depiction of an appropriate conceptual framework for developing usable and valid decision support systems (DSSs) to select or design water or wastewater treatment systems. A thorough investigation of the methods used to develop DSSs benchmarked a systematic approach to developing DSSs, which includes the analysis of the treatment problem(s), knowledge acquisition and representation, and the identification and evaluation of criteria controlling the selection of optimal treatment systems. Finally, it was concluded that there is a need to develop integrated DSSs that are generic, user-friendly and employ a systems analysis approach. Another significant contribution of this research is applying a systems analysis approach to outline aspects of implementation, management, and governance of POU and POE water treatment systems. The analysis also included a timeline of the progress of POU and POE treatment from regulatory, industry and certification, and research perspectives. Results of the analysis were considered the first step of a conceptual framework for the sustainability assessment of POU and POE treatment systems which acts as the basis for developing a decision support system that will help select sustainable POU or POE treatment systems. In the context of POU and POE treatment, sustainability encompasses providing: (a) safe drinking water to help maintain good human health and hygiene; (b) minimum negative impact on the environment; (c) better use of human, natural, and financial resources; (d) a high degree of functional robustness and flexibility; and (e) cultural acceptance thus encouraging responsible behavior by the users. The most significant contribution of this research is developing, for the first time, a set of sustainability criteria, objectives, and quantifiable indicators to properly assess the sustainability of the various POU and POE alternatives. Twenty five quantitative and qualitative indicators covering technical, economic, environmental, and socio-cultural aspects of implementing a POU or a POE system were defined. Results of a survey of experts’ judgment on the effectiveness of the developed list of indicators generated 52 comments from 11 experts, which helped in refining and enhancing the list. The conceptual framework for assessing the sustainability of POU and POE systems represented a blueprint for building the decision support system. Decision logic and cognitive thinking was used to formulate the calculation of the 20 refined indicators. The Analytical Hierarchy Process (AHP), a recognized Multi-criteria Decision Analysis (MCDA) tool, was employed to construct the structural hierarchy of sustainability indicators. Pairwise comparison was used to help in the analysis of indicators' relative importance and develop the indicators’ weights. A survey was designed to develop the relative weights of the indicators based on the average response of 19 stakeholders to a series of pairwise comparison questions pertaining to the relative importance of the indicators. Finally, the practical contribution of this research is the development of, for the first time, a new Decision Support System for Selecting Sustainable POU and POE Treatment Systems (D4SPOUTS) suitable for a particular water treatment case. The MCDA technique explained above is combined with designed screening rules, constraints, and case characteristics to be applied to a knowledgebase of POU and POE treatment systems incorporated in the DSS. The components of the DSS were built using Microsoft® Excel® and Visual Basic® for Applications. The quality of the DSS and aspects of its usability, applicability, and sensitivity analysis are demonstrated through a hypothetical case study for lead removal from drinking water. This research is expected to assist water purveyors, consultants, and other stakeholders in selecting sustainable and cost effective POU and POE treatment systems.

Magnetic particles have attracted increasing attention in fields ranging from separation processes to electromagnetic information storage an medical application. Various approaches for their synthesis have been developed and studied to satisfy the criteria of production. Improvement and optimization of size, stability, and functionality is of vital importance in biological applications. The main aspect of project, initially, was to study the application of aqueous functionalized magnetic nanoparticles coupled with high gradient magnetic separation technique for the removal of trace residue of organic contaminants from drinking water. However, the importance of synthesizing stable ferrofluid for this purpose became clear later and took precedence over the initial objective. Different approaches were adopted, such as the incorporation of poly(ethylene glycol) methacrylate, ethylenediamine, and chitosan, to enhance the stability of magnetic particles. However, these surface modifications had unfavorable effect on the stability of initial particles. In accord with the initial objective of the project, the possibility of utilization of β-cyclodextrin, as organic pollutant entrapment agent, was investigated in preliminary studies conducted on its interaction with a model compound, procaine hydrochloride. The outcomes of these experiments suggest its potential as a biocompatible removal agent for the elimination of organic pollutant in drinking water system, or other applications that require selective separation of organic compounds.