Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Aral, Mustafa; Committee Member: Guan, Jiabao; Committee Member: Jang, Wonyong; Committee Member: Kim, Seong-Hee; Committee Member: Uzer, Turgay. Part of the SMARTech Electronic Thesis and Dissertation Collection.

The goal of this research was to maintain excellent water quality at reduced chemical operations cost. Chemical usage data at the Austin water treatment plants were examined by identifying trends and investigating suspected inefficiencies. The investigation consisted in jar test experiments, plant-scale experiments, and equilibrium modeling. Lime and ferric sulfate were suspected to be added inefficiently with respect to cost while the other treatment chemicals were assessed to be added efficiently. Lime was investigated in greater depth than ferric sulfate because ferric sulfate was better characterized in its effect on finished water quality within the range of interest. The goal of lime addition is to remove hardness from the water by a process called lime softening. Hardness removal decreases corrosion in transmission lines and prevents deposition of unwanted solids in household appliances. Additionally, lime softening aids in particle removal and disinfection-by-product precursor reduction. The efficiency of lime addition was evaluated based on settled water pH and causticity goals, which serve as the operating parameters for the water treatment plants. The most efficient lime softening occurs when multiple softening goals are simultaneously achieved. First, the dissolved calcium concentration must achieve a minimum. Second, the dissolved magnesium concentration must be reduced by at least 10 mg/L as CaCO₃. Third, total alkalinity must be preserved at its maximum concentration while also achieving excellent hardness removal. Fourth, natural organic matter (NOM), which serves as a precursor for disinfection-by-products, must be removed sufficiently to achieve DBP reduction goals. Finally, the turbidity in the effluent from the settling basin must be below 2.0 NTU. Through the chemical investigation of lime based on existing scientific literature, computer modeling, jar test experiments, and full-scale testing, it was determined that the optimal condition operating condition for lime softening was a settled water pH range from 10.0 - 10.1. / text

Silver nanoparticles (Ag NPs) are frequently added as a disinfectant to ceramic filters used for household drinking water treatment. To provide suspension phase particle stability, Ag NPs can be synthesized using a number of different molecules to cap the metal core. The goal of this doctoral work was to advance the fundamental understanding of how stabilizing agents influence the attachment and detachment of Ag NPs from ceramic water filters. To achieve this goal, deposition experiments onto Al₂O₃ membranes and clay-based ceramic filters were performed using Ag NPs stabilized by three different agents: citrate, polyvinylpyrrolidone (PVP), and branched polyethylenimine (BPEI). Laboratory and field- scale filtration experiments were also conducted to evaluate the removal of Ag NPs from ceramics under different water conditions -- the presence of hardness and natural organic matter (NOM). Citrate-stabilized Ag NPs were found to have the highest attachment densities, regardless of filter material. Differing attachment densities for the three types of Ag NPs were extensively explained using a combination of classic Derjaguin, Landau, Verwey and Overbeek (DLVO) theory, steric forces, and particle-particle interaction energy calculations. A multilevel statistical model was built to describe the removal of Ag NPs from ceramic water filters under different water conditions. The type of Ag NP was found to affect the initial release of Ag from the filters, while the interaction of the type of Ag NP and water were found to affect the rate of removal. Hardness and NOM prolonged the release of Ag from ceramic water filters.

M. Tech. Water Care. / Aims to evaluate promising technologies for local application in the removal of viruses and protozoan parasites and to provide guidelines for the selection and use of appropriate home water treatment systems that could be used in rural households.

Application of low pressure membranes in drinking water treatment, including both microfiltration (MF) and ultrafiltration (UF), have witnessed a rapid increase in the past decades. Low pressure membranes are considered a good technology in retrofitting existing conventional drinking water treatment plants or in newly constructed plants to meet the stringent regulations for drinking water treatment that aim at preventing health risks of waterborne diseases. Enteric viruses are one of the major types of waterborne pathogens, and they can be commonly found and are persistent in the environment. Both the United States and Canada require a 99.99% (4-log) removal of viruses during the drinking water treatment train. Unlike MF membranes, UF membranes have a very good potential for removing enteric viruses from the water due to their smaller pores comparable to the size of viruses. Drinking water regulations/guidelines in both the United States and Canada do not grant UF membranes any removal credit for viruses by default; however they have the provision that, in certain cases, virus removal credit may be granted based on pilot scale challenge testing. A better understanding of the interaction between the UF membranes and virus rejection can help to establish a removal credit for UF membranes. An essential part of this will be the effect of the membrane operation on the rejection of viruses to determine if UF membranes can offer a consistent removal of viruses. Membrane fouling is one of the major problems in membrane operation and it can affect the rejection characteristics of the membrane and improve its performance. The aim of this study was to investigate the removal of virus surrogates (MS2 and φX174 bacteriophage) using a commercial UF membrane under different conditions, to obtain information about the removal mechanisms of viruses. The experimental filtration unit was designed to have similar conditions like the full scale membrane treatment plants. The UF membrane used in this study provided very good removal of both MS2 and φX174 bacteriophage. The obtained results were consistent and in agreement with the expected removals based on the membrane characterization results and types of virus surrogate. As part of this work, a detailed study to improve methods for characterizing the pore size distribution of membranes was conducted. In the second part of the study, two different types of surface waters were used to study the effect of membrane fouling on virus removal. It was found that mainly hydraulically irreversible fouling could significantly improve the virus removal by UF membranes. Different cleaning regimes that are used in treatment plants had varying effects on virus removal. After maintenance cleaning, virus removal remained higher than that of clean membranes, and only chemical cleaning was effective for completely removing membrane foulants and returning virus removal back to base levels. Advanced analytical techniques were used to define the nature of the fouling layer on the membrane surface and how the foulants affected the rejection of viruses. Finally, our study showed that UF membranes are a robust treatment technology for removing different types of enteric virus surrogates from water under different operational conditions. Close monitoring of the UF unit performance and direct integrity testing can possibly detect membrane problems that can affect the rejection of viruses. Based on the virus physical characteristics and a detailed study of the membrane surface characteristics, especially the pore size distribution of the membrane, the removal of the specific virus can be closely estimated.

In the theoretical part of diploma thesis is elaboreted literary search relating to problems with using of various modifications of coagulation tests. The experimental part of diploma thesis is focused on comparison of three types of coagulation tests during treatment of model water with increased content of humic matter. Concretly was compared classic jar test, modified jar test and centrifugation test. As a coagulant was used ferric sulphate. The efficiency of treatment was tested under various conditions (temperature, time of fast mixing and intensity of slow mixing). Information capability of results was evalueted on the basis of absorbance by 254 nm and 387 nm, residual concentration of iron and dichromate value. Obtained results were numerically processed and they are presented in the form of tables and graphs.

General part of thesis deal with information on technology of water treatment and its changes at drinking water treatment plant Štítary. In experimental part of the document are presented treated data on monitoring of concentration of organic matter along the technological line of reconstructed drinking water treatment plant in Štítary for period since 2009 to 2010.

Submitted in fulfilment of the requirements of the Degree of Master of Technology: Chemical Engineering, Durban University of Technology, 2013. / Lack of access to clean and safe potable water, especially for people living in rural areas of developing economies, is a matter of great concern in different parts of the world. Measures taken to address the challenges arising from this problem include the improvement of existing water purification methods and development of new appropriate technologies such as point of use (POU) water treatment technologies. One such appropriate POU technology is the Remote Rural Water Treatment System (RRWTS) developed at Durban University of Technology (DUT) in South Africa. The RRWTS is based on polyester woven fabric microfiltration (WFMF) membranes and other locally sourced materials. The filtration unit consists of flat sheet modules assembled into a pack and permeate outlets connected to a manifold and then to a tap. The system is gravity driven and therefore eliminates the use of pumps and electricity. This system has shown potential for use in water treatment as it produces permeate with turbidity below 1 NTU, has a high permeate flow rate, and is easy to use and maintain. However, the major challenge facing its use is that permeate does not meet the set microbiological standards for drinking water (zero E. coli in 100 mL treated water). The RRWTS can ideally remove 95 to 99 per cent of the influent E. coli. This necessitates the use of a separate disinfection step, often using chlorine for complete removal of microbial contaminants. The objectives of this study were: to investigate the incorporation of silver nanoparticles (AgNPs) into the WFMF membrane; to evaluate the disinfection efficacy of the AgNPs impregnated filter (coated filter); and to determine the long term performance of the coated filter in terms of disinfection and silver elution (90 days). The study was conducted in four stages. Firstly, AgNPs were incorporated on the membrane using in situ chemical reduction of silver nitrate using sodium borohydride. Secondly, the filters were characterized using scanning electron microscopy (SEM) to determine the morphology, and the Sessile drop method for contact angle measurement was employed to determine the membrane hydrophilicity. In addition, X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR) spectroscopy and UV- Visible Spectroscopy iii were used to investigate the presence of AgNPs on the coated filter. Thereafter, the antibacterial efficacy of the filters was evaluated using a laboratory scale experimental rig and different microbial assays. Raw river water and deionized water spiked with E.coli (synthetic feed) were used as feed. Lastly, the effects of concentration of E.coli in the feed and silver elution on the disinfection performance of the coated filter over time were investigated. The performance criteria were based on permeate quality and they included: turbidity, concentration of E.coli, and silver concentration. The characterization results depicted that AgNPs were successfully immobilized on the WFMF membranes by in situ chemical reduction. The incorporation of AgNPs was ascertained using UV-Vis Spectrophotometry, FT-IR and XRD. The Sessile drop test indicated that the membrane became more hydrophilic (77 per cent decrease in water contact angle) and the permeability increased significantly as a result of the coating (p <0.05). The coated filters demonstrated excellent filtration performance producing permeate with turbidity less than 1 NTU for feed turbidities between 40 and 700 NTU. The disinfection efficacy was found to be excellent, producing permeate with zero E.coli concentration for feed concentrations between 10,000 CFU/ 100 mL and 85,000 CFU/100 mL. The E.coli removal efficiency was 100 per cent for a period of 63 days of continuous filtration. The ICP Atomic Emission Spectrometer (ICP-AES) results showed that the leaching of silver from the coated filters over time (90 days) was always below 0.1 mg/L which is the widely accepted guideline for potable water. From the literature surveyed, this is the first study which investigated the use of AgNPs in WFMF membranes for potable water disinfection. The coated filters treated water to the set international standards for potable water in terms of physical and microbiological quality. However, the study did not comprise investigation into the effect of different silver loadings on the filter performance. The study also employed E.coli as the indicator organism for faecal contamination. The results obtained can be used as a model for future work using other microorganisms and different silver loadings in order to compare the performance.

<p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p> / <p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>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.</p>

This diploma thesis is aimed at the evaluation of the efficiency of surface water treatment technology in water treatment plant U svaté Trojice (Kutná Hora, Vrchlice reservoir). The plant performs destabilisation of impurities by coagulant aluminium sulphate (Al2(SO4)3 . 18 H2O) followed by aggregation induced by mixing with perforated baffles. Suspension is removed by double-stage separation process by means of sedimentation and filtration. When increased concentrations of manganese occur in raw water, manganese is removed by means of oxidation by potassium permanganate. Firstly, the quality of raw water was analysed. Then, the reaction conditions for the effective destabilisation (pH, dose of coagulant) were set using the jar tests. Moreover, sedimentation analysis was used to evaluate the properties of formed suspension and the length of filter cycles was assessed. Measurements were conducted between September 2012 and February 2013. Average value of raw water pH was 7.3, alkalinity was 1.64 mmol/l. DOC concentrations during September and October 2012 were equal to 6.7 mg/l and during November 2012 - February 2013 were 7.6 mg/l. Very low concentrations of aluminium (< 0.02 mg/l) were ascertained throughout the whole period investigated. Results of the jar tests showed that the optimum pH for...