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1
Hubler, David K. "Modeling Electrochemical Water Treatment Processes." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/265367.
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Several electrochemical processes are modeled at process levels and atomic scales. Processes are presented for acid generation and ion exchange media regeneration, along with corresponding process models. Transport and reaction processes in individual ion exchange beads are also modeled. Acids of mild strength (pH = ~1-2) are generated from electrolyte solutions and their strength is effectively modeled as a function of time. The regeneration of ion exchange media is also modeled, to close agreement with measurements, and the process model is reconciled with a model for solute flux from an individual ion exchange bead. Together, the models show that the "gentle" regeneration process is controlled by the plating rate. Processes interior to the particle are controlled by diffusion, but all processes are faster than the characteristic time for plating. In a separate process, an electrochemical method is used to produce hypochlorite for disinfection. The process generates perchlorate as a toxic byproduct. Density function theory is used to construct an atomic-scale model of the mechanism for producing perchlorate, as well as the aging of the boron-doped diamond anode used in the process. The mechanism shows that the boron-doped diamond surface plays an important role in chemisorbing and stabilizing radicals of oxychlorine anions, allowing the radicals to live long enough to react and form higher ions like perchlorate. Wear mechanisms that occur on the anode are shown to oxidize and etch the surface, changing its chemical functionality over time. As the surface ages, the overpotential for water oxidation is decreased, decreasing the efficiency of the electrode.
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Bailey, Lucinda. "Microbial resistance to advanced water treatment processes." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403584.
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See, Hwee J. "Optimisation of water and wastewater treatment processes." Thesis, University of Cambridge, 2002. https://www.repository.cam.ac.uk/handle/1810/272064.
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Arnette, Verna J. "Cyanotoxin Removal in Drinking Water Treatment Processes." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258475751.
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Hung, Chien-ho. "Fate of thiocyanate in biological treatment processes." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/20864.
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Lau, Sze Chun Gary. "Physical characteristics of flocs in water treatment processes." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444945/.
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Aluminium sulphate, calcium nitrate, and two cationic polymers have been used to coagulate and flocculate dilute kaolin and latex suspensions (< 100 mg/1) in a stirred vessel. The effects of the different destabilising agents on the resulting floes have been monitored using a simple continuous optical technique based on turbidity fluctuations and the behaviour of these floes under shear conditions and the possibility of subsequent floe re-formation have been investigated. The results showed vast differences in behaviour regarding to floe breakage and re formation between the systems. For a low molecular weight, high charge polymer (A) and calcium nitrate, floe breakage was almost completely reversible. However, for aluminium sulphate, limited floe re-formation was observed on restoring previous shear conditions after breakage. For a high molecular weight polymer (B), limited floe breakage was observed. Moreover, a new automated monitoring technique based on cake and vacuum filtration has been developed to assess the filterability of floes. The technique is reliable and provides reproducible results. The results showed that polymer A was more effective in enhancing filterability than polymer B for both kaolin and latex suspensions. However, polymers do not have a significant influence on the filterability of floes if the primary particles involved have high sphericity.
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Bruzzone, David W. "The effect of various oxidants on water treatment processes." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/51900.
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The effects of four oxidants upon water treatment process parameters were investigated. The four oxidants under consideration were ozone, chlorine dioxide, potassium permanganate, and chlorine, Experimentation was directed towards the impact of these oxidants upon turbidity, TOC, and color removal, as well as reduced manganese oxidation. Studies were conducted with an experimental water with enhanced TOC levels. Experimentation was accomplished by a series of jar tests in which solution pH, coagulant dose, and oxidant dose were varied.
Results show that, in general, oxidant application had either no impact or a negative impact upon TOC, turbidity, and color removal. Further deterioration of finished water quality was observed with increasing oxidant dose. Reduced manganese was oxidized by both potassium permanganate and chlorine dioxide. Ozone effectively oxidized reduced manganese in waters of low TOC, while chlorine was an ineffectual oxidant.
Additionally, particle counts were conducted. Results show that the application of an oxidant increased the number of smaller particles present alter settling However, this immense of particles did not significantly alter settled turbidity levels.Master of Science
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Brenda, Marian [Verfasser]. "Hybrid Sludge Modeling in Water Treatment Processes / Marian Brenda." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2015. http://d-nb.info/1112044841/34.
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Stevens, Chad Howard 1980. "Assessment of desalination treatment processes for future water supplies." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/85745.
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Kennedy, Marla J. "Multi-Objective Optimization of Conventional Surface Water Treatment Processes." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1477332989340079.
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Mohammed, Alahmad Suleiman. "Electrochemical and Electroflotation Processes for Milk Waste Water Treatment." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu151309400205639.
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Philippe, Karine K. "The role of advanced oxidation processes in drinking water treatment." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/6782.
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Removal of natural organic matter (NOM) is an ever growing challenge for water utilities as many surface waters used for drinking water in the UK exhibit increasing organics levels and it is well known that these organics can lead to problems such as water colouration, unpleasant odour and taste, bacterial growth and disinfection by-products (DBPs) formation. NOM is traditionally removed by coagulation, however in the case of hydrophilic organic matter rich waters the performances of these processes are not able to remove sufficient organic matter leading to potential failures of DBP regulations. Here two advanced oxidation processes (AOPs) UV/H2O2 and TiO2 photocatalytic oxidation were studied to investigate how they could be integrated in a drinking water flowsheet to meet this challenge. Substantial structural changes in the organic matter were observed: loss of aromaticity and double bonded character, shift towards lower molecular weight (MW) more hydrophilic compounds and formation of oxygenated by-products. Although hydrophobic rich waters seem more suitable to AOP treatment as preferential attack of high MW hydrophobic compounds was demonstrated, no correlation was found between physical properties of nine NOM surrogates and removal by UV/TiO2. Dark adsorption onto TiO2 was shown to remove preferentially high molecular weight hydrophobic anionic compound such as tannic acid. UV/H2O2 combined with coagulation did not show any significant benefits in NOM removal as UV/H2O2 appeared to target similar components as coagulation (high MW, hydrophobic and charged) and to form by-products recalcitrant to coagulation. The combination of both AOPs with fresh GAC showed moderate benefits in Abstract ii trihalomethane formation potential (THMFP) and non purgeable organic carbon (NPOC) removal highlighting the role of size and surface chemistry on adsorption onto GAC. Biodegradability of the water did not exhibit any significant change after both AOP treatments within the studied conditions possibly due to insufficient UV irradiation and presence of organics recalcitrant to biodegradation.
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Scriven, Richard James. "The impact of physicochemical water treatment on downstream clarification processes." Thesis, University of Surrey, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362601.
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Vater, Katherine Ann. "Appropriate technology water treatment processes for MaeLa Temporary Shelter, Thailand." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43875.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.Includes bibliographical references (p. 71-74).
This thesis recommends the use of horizontal-flow roughing filters to treat spring water of variable annual quality in MaeLa Temporary Shelter, Thailand. The public drinking water system for 45,000 refugees is overseen by Aide Medicale Intemacionale, with which this project was conducted. Half the drinking water for the camp is provided by thirteen springs. The volume and turbidity of these springs varies annually, correlating with the rainy and dry seasons. Treating the varying turbidity and volume at these sources so that the water can be effectively disinfected is the treatment goal. Available materials and operation and maintenance capabilities are also design parameters. Horizontal-flow roughing filtration was determined to fit these parameters and a design with two equivalent filters operating in parallel is recommended. One important feature of the filters is baffles that dictate the flow path of water through the filter. A second feature is an outflow at the top of the filter that will maintain a constant water volume in the filter. The feasibility of the design is based on flow tests and turbidity measurements taken on site as well as weekly flow rates and turbidities for 2007 provided by AMI. The requirements for mechanical regeneration of the filter are also determined.
by Katherine Ann Vater.
M.Eng.
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Ferrer, Mallén Olga. "Substitution of conventional pre-treatment units by membrane based processes in drinking water treatment." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/334975.
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This thesis focused on the feasibility of substituting, partially or totally, drinking water treatment plant (DWTP) conventional pre-treatment by membrane based units, in particular by ultrafiltration (UF). For such purpose, bench and pilot scale tests with natural water were conducted, first, to address the technical feasibility and, second, to optimize its performance in order to determine whereas the proposed scheme was competitive from hydraulic and quality perspectives with the current conventional pre-treatment. Moreover, tailored microbes based tests were defined to assess its proper functioning and reliability, and additional advantages related to direct UF besides those purely related to the pre-treatment unit were investigated. The case study selected was Sant Joan Despí DWTP (Barcelona, Spain) due to its particularities: it treats Llobregat River water, which is a highly variable water resource in terms of quality and quantity, and it is a complex multistage system. As a result, this study covered a wide range of conditions and the technology under consideration could be pushed to its limits.
Results showed that direct UF of raw river water was a competitive alternative to dioxichlorination, coagulation/flocculation, settling and sand filtration. The pilot plant was able to continuously treat raw river water during 2 years, independently of its quality (e.g. turbidity > 1,000 NTU), delivering water of high and stable quality, both physico-chemically and microbiologically. In terms of pre-treated water quality, most of the physico-chemical parameters monitored presented lower values and variability in the direct UF scheme than in the conventional pre-treatment process. From a microbiological perspective, the direct UF scheme tested ensured an average removal of > 5 log10 units of bacteria and viruses greater than 60 nm. The highest water yields achieved ranged between 94.0%-94.7% in optimal conditions, involving 1 or 2 chemically enhanced backwashes (CEBs) per day, transmembrane pressure (TMP) below 1 bar, filtration fluxes of 40¿70 L/(m2¿h) and low reagents consumption. When a micro-coagulation previous to the UF was applied, the increase of the hydraulic resistance during filtration was decreased and stabilized, especially in winter, the hydraulic cleaning efficiency raised and the CEB frequency diminished.
Since fouling indicators (SDI15 and MFI0.45) of the direct UF permeate were lower than those associated to the conventional pre-treatment, the subsequent reverse osmosis (RO) unit would require less chemical cleanings and thus, its lifetime would be extended. In addition to this, besides the economic savings associated to the significant reduction of reagents dosed within the direct UF scheme (chemical disinfectants and coagulants mainly), a minimization of risk of RO membrane degradation was demonstrated. Studies concerning the effects on physico-chemical and transport properties of RO membranes exposed to chemicals used within the conventional pre-treatment scheme but avoided in the direct UF treatment were also undertaken. An advanced characterisation of the exposed membranes enabled understanding the RO membranes performance changes with its composition and structure modification.
The implementation of direct UF would imply the pre-treatment being a single membrane filtration step. This has advantages in terms of process complexity, space requirements, as well as avoidance of chemical based disinfectants dosage. Nevertheless, the preservation of its separating properties along time is of utmost importance, especially from a microbiological standpoint. Consequently, microbes based tailored tests aiming at assessing membrane integrity were defined and conducted periodically, to determine the removal capacity reliability of the pre-treatment scheme proposed in this thesis. Results showed that membrane integrity had not been compromised despite the challenging conditions that direct UF posed.Aquesta tesis s'ha centrat en l'estudi de la substitució, total o parcial, de l'etapa de pre-tractament d'estacions de tractament d'aigua potable (ETAPs) per processos de membrana, en particular per ultrafiltració (UF). Per a tal fi, es van realitzar experiments a nivell laboratori i pilot per, en primer lloc, avaluar la seva viabilitat tècnica, i en segon, optimitzar el seu funcionament per determinar així si l'esquema de tractament proposat era competitiu des d'un punt de vista hidràulic i de qualitat amb el pre-tractament convencional actual. A més, es van definir assajos per assegurar el seu correcte funcionament i fiabilitat, i es van identificar avantatges addicionals a les purament associades a l'etapa de pre-tractament. El cas d'estudi seleccionat va ser l'ETAP de Sant Joan Despí (Barcelona) degut a les seves particularitats: tracta aigua del riu Llobregat, que és un recurs altament variable en termes de qualitat i quantitat, i és un sistema multi-etapa complex. En conseqüència aquest estudi va cobrir un ampli rang de condicions i va permetre portar la tecnologia en qüestió a condicions límit. Els resultats vam mostrar que la UF directa d'aigua crua de riu és capaç de substituir, i resulta competitiva, amb la dioxicloració, coagulació/floculació, decantació i filtració per sorra. La planta pilot va ser capaç de tractar contínuament aigua crua durant 2 anys, independentment de la seva qualitat (ex. terbolesa d'entrada > 1000 NTU), produint aigua de qualitat alta i estable, tant fisicoquímicament com microbiològicament. La majoria dels paràmetres fisicoquímics avaluats van presentar valors inferiors i amb menor variabilitat en l'esquema d'UF directa que en el pre-tractament convencional. Des d'una perspectiva microbiològica, l'esquema d'UF directa avaluat va assegurar una eliminació > 5 log10 unitats de bactèries i virus de tamany superior a 60 nm. El rendiment hídric va oscil.lar entre 94.0-94.7% en condicions òptimes, requerint 1 o 2 contra rentats químics al dia, una pressió transmembrana per sota d'1 bar, fluxos de filtració entre 40-70 L/(m2.h) i un baix consum de reactius químics. En aplicar una micro-coagulació prèvia a la UF, l'increment de la resistència hidràulica durant la filtració va disminuir i es va estabilitzar, l'eficiència del contra rentat va augmentar, i la freqüència dels contra rentats químics va davallar. Degut a que els indicadors d'embrutiment (SDI15 i MFI0.45) del permeat d'UF directa van resultar inferiors als del pretractament convencional, és d'esperar que la unitat següent d'osmosis inversa (OI) precisi menys neteges químiques i per tant, la seva vida útil es prolongui. Addicionalment, a part de l'estalvi econòmic associat a la reducció significativa de reactius dosificats en l'esquema l'UF directa (desinfectants químics i coagulants principalment), es va demostrar una disminució del risc de degradació de les membranes d'OI. Es van dur a terme estudis avaluant els efectes de l'exposició de certs químics (dosificats en el pre-tractament convencional però no en l'UF directa) en les propietats fisicoquímiques i de transport de membranes d'OI. Una caracterització avançada va permetre relacionar els canvis de funcionament de les membranes d'OI amb els seus canvis de composició i d'estructura. La implementació de la UF directa implica que el pre-tractament consisteixi únicament en una etapa de filtració. Això suposa avantatges en termes de complexitat del procés, requeriments d'espai així com d'evitar l'ús de desinfectats químics. Tanmateix, la preservació de les seves propietats de separació al llarg del temps és de gran importància, sobretot des d'un punt de vista microbiològic. En conseqüència, es van definir i dur a terme periòdicament assajos en base a microorganismes per avaluar la integritat de la membrana d'UF directa. Els resultats van indicar que la integritat de la membrana d'UF s'havia preservat durant els 2 anys d'estudi, malgrat les condicions severes que la UF directa va suposar
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Collins, Michael Robin. "Removal of aquatic organic matter and humic substances by selected water treatment processes." Diss., The University of Arizona, 1985. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1985_382_sip1_w.pdf&type=application/pdf.
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Rolph, Catherine. "21st Century biological processes for metaldehyde removal in drinking water treatment." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/10011.
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In recent years advances in analytical techniques have resulted in the reporting of previously undetectable pesticides in treated drinking water. Most pesticides are traditionally removed using ozone and granular activated carbon, however polar pesticides such as metaldehyde are not effectively removed in this way. Biological treatments for drinking water are a potential option for metaldehyde removal. Experiments were undertaken firstly to understand if metaldehyde can be removed using a biological mechanism and whether this mechanism can be captured and enhanced. It was found that metaldehyde can be effectively degraded using a sand with an active biofilm. This mechanism can be enhanced using a period of acclimation where the biofilm is exposed to higher metaldehyde concentrations to achieve increased degradation rates, this rate is maintained for several days even in the presence of lower metaldehyde levels. Removal times can also be enhanced using a fluidised column, which was found to be more effective that a traditional downflow filter for metaldehyde degradation. Pilot scale experiments demonstrated the potential for this technology to be implemented at full scale. Finally, an economic analysis identified that a fluidised bed bioreactor is economically viable compared to current treatment options.
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Price, Robert. "A study of hybrid clarification-filtration processes for potable water treatment." Thesis, University of Nottingham, 2005. http://eprints.nottingham.ac.uk/12410/.
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This research investigates the removal of natural organic matter (NOM) from low turbidity waters by optimising an integrated coagulation and membrane filtration process. In conjunction with a regional water utility, the feasibility and operability of pre-coagulation with ultrafiltration membrane units, is investigated at both the fundamental and applied levels. The pH of coagulation greatly affects the growth of flocs. Although flocs are produced over the range of pH values, there is a significant improvement in performance at the optimum pH. The results show that for ferric sulphate, the optimum pH value for coagulation was 4.8; for ferric chloride the optimum pH value was 5.0; and for alum the optimum pH value was 6. Manipulation of the mixing regime during orthokinetic flocculation allows control of the final floe size. A high shear rate (447 s-1) induces greater particle collision and micro-floc formation, allowing an increased rate of growth during slow mixing. A mixing regime of 60 seconds rapid mixing (shear rate G= 447 s-1) followed by 3 minutes slow mixing (shear rate G= 20 s-1) is required for flocculation of the NOM and adequate enmeshment and removal of excess iron. Experiments conducted with the optimised coagulation regime and a Norit hollow fibre ultrafiltration membrane, operated in dead-end mode, leads to significant fouling. The results for the submerged Zenon ultrafiltration membrane also indicated membrane fouling, when the coagulation regime was optimised for NOM reduction and iron removal. Changing the coagulation regime altered the level of membrane fouling. It can be concluded that the optimum coagulation conditions in conventional water treatment are not always the optimum conditions for coagulation with ultrafiltration treatment and the unconventional coagulation conditions can be much more effective, than the conventional ones, in the context of membrane filtration, depending on the raw water characteristics.
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Sanches, Sandra. "Integration of Membrane Filtration and Photolysis Processes for Drinking Water Treatment." Doctoral thesis, Universidade Nova de Lisboa. Instituto de Tecnologia Química e Biológica, 2013. http://hdl.handle.net/10362/12031.
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Dissertation presented to obtain the Ph.D degree in Engineering and Technology Sciences, Chemical Engineering.Water is a fundamental resource for life. The presence of hazardous micropollutants such as pesticides and hormones in drinking water sources as well as the evidence of their presence in several treated waters raised concerns regarding the quality of the water intended for human consumption. The development of new technologies which are able to cope with these micropollutants and ensure the fulfillment of future more stringent regulations is therefore needed. Low pressure ultraviolet direct and indirect photolysis (using hydrogen peroxide and titanium dioxide) and nanofiltration are extremely promising technologies to effectively remove organic micropollutants from water.(...)
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Liu, Yen-Ling. "The Fate of Cyanotoxins in Drinking Water Sources and Treatment Processes." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1515021263671957.
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Wu, Shimin, and Shimin Wu. "Fate of Glucocorticoid Receptor Agonists During Water and Wastewater Treatment Processes." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/623167.
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In recent years, endocrine disruption of corticosteroid signaling pathways in wildlife and humans by environmental chemicals have attracted increasing attention. The integrated potential of chemicals in the aquatic environment that disrupt corticosteroid actions have been evaluated using in vitro glucocorticoid receptor (GR) mediated bioassays. Exogenous natural and synthetic corticosteroids (CSs), which are widely used in human and animal therapeutic applications, were demonstrated to be the most important GR agonists, that can potentially cause adverse effects, especially on aquatic organisms. To date, only a few studies have investigated the occurrence and behavior of GR agonists in the aquatic environment and their removal in conventional wastewater treatment plants. Furthermore, there are hardly any data reported on the removal of GR agonists by advanced water and wastewater treatment, especially those synthetic CSs with high potency. To further understand the fate of GR agonists in water and wastewater treatment processes, a sensitive and robust LC-MS/MS method was successfully developed for analyzing a wide range of GR agonists in various environmental waters. The occurrence of GR agonists in surface water and groundwater was monitored along the Lower Santa Cruz River (SCR). Several GR agonists were detected, and a trend of degradation was observed downstream the two WWTP outfalls for both surface water and groundwater. The fate of GR agonists in a local wastewater treatment plant (WWTP) was investigated, and up to 14 GR agonists were detected at different stages. Highly potent synthetic CSs, including clobetasol propionate (CBP), fluticasone propionate (FTP), fluocinolone acetonide (FCA), and triamcinolone acetonide (TCA), were poorly removed in WWTP. Negative removal of some CSs was observed in primary treatment, which may due to the deconjugation of CS conjugates. Removal of GR agonists in secondary effluent during various advanced water treatment processes, including UV, ozonation, MF, RO and chlorination, were studied. UV and RO appeared to be the most efficient treatment process for the attenuation of GR agonists, followed by ozone, while chlorination had little effects on GR agonists in water. Bench-scale experiments were then carried out to investigate the removal of GR agonists by ultraviolet based advanced oxidation processes (UV/AOPs), and powder activated carbon (PAC). UV/chlorine and UV/H2O2 were demonstrated to be effective in removal GR agonists in wastewater, and UV photolysis would be the predominant mechanism in UV/AOP processes. Four types of PACs were tested for removing GR agonists in wastewater effluent, and Cabot HDB carbon was suggested, while Calgon PWA carbon was not recommended due to its low removal efficiency.
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Bonneville, Craig R. "Effects of pre-ozonation and selected advanced water treatment processes on Mount Seymour impoundment water." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0003/MQ59781.pdf.
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Steinwinder, Thomas Riemann Zhao Dongye. "Engineered treatment of As-laden regeneration brine from ion exchange processes." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/master's/STEINWINDER_THOMAS_33.pdf.
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Trozell, Oskar, Daniel Wiman, Elis Wiggins, Elin Stigenberg, Alva Bergström, and Emilia Andersson. "Sustainable water treatment processes : Scenarios for a better environment in Håbo municipality." Thesis, Uppsala universitet, Institutionen för kemi - Ångström, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-448625.
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Clean drinking water is a vital part of our society and a basic human right. With an ever growing population and a decreasing quality of raw water, new methods need to be introduced to keep up with the demand for clean, biostable, and sustainable production of drinking water. The aim of this study is to evaluate Håbo municipality’s increasing usage of chemicals in their water treatment process and to investigate current and future possible technologies for water treatment for Håbo to make their process more sustainable. In this study four scenarios of different cost and change of today’s water treatment plants are presented, while our overall recommendation is to build a new facility. A new plant with new treatment methods such as ultrafiltration is most in line with Håbo municipality’s vision of decreasing chemical usage and sustainability, all while maintaining the water quality. Due to Håbo’s growing population and today’s water plants running close to maximum capacity, a new facility with a larger capacity should be considered.
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Vagadia, Aayushi R. "Comparison of Bacterial and Viral Reduction across Different Wastewater Treatment Processes." Thesis, University of South Florida, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10977800.
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Today billions of people live without access to basic sanitation facilities, and thousands die every week due to diseases caused by fecal contamination associated with improper sanitation. It has thus become crucial for decision makers to have access to relevant and sufficient data to implement appropriate solutions to these problems. The Global Water Pathogen Project http://www.waterpathogens.org/ is dedicated to providing an up-to-date source of data on pathogen reduction associated with different sanitation technologies that are important if the world is to achieve the Sustainable Development Goals (SDGs) related to health and sanitation provision. In this research, a subset of the Global Water Pathogen Project (GWPP) data is used to access the reduction of bacteria and viruses across different mechanical and natural sanitation technologies. The order of expected removal for bacteria during wastewater treatment was reported as highest for a membrane bioreactor (4.4 log10), waste stabilization pond (2.3 log10), conventional activated sludge (1.43 log10), anaerobic anoxic oxic activated sludge (1.9 log10), trickling filter (1.16 log10), and upflow anaerobic sludge blanket reactor (1.2 log10).
Furthermore, the order of expected removal for viruses was reported as highest for a membrane bioreactor (3.3 log10), conventional activated sludge (1.84 log10), anaerobic anoxic oxic activated sludge (1.67 log10), waste stabilization pond (1 log10), upflow anaerobic sludge blanket reactor (0.3 log10) and trickling filter (0.29 log10). It was found that hydraulic retention time (HRT) had a statistically significant relation to the reduction of bacteria in an anaerobic, anoxic oxic treatment system. Similarly, a significant relation was found between the number of waste stabilization ponds in series and the expected reduction of bacteria. HRT was also found to be a significant factor in virus reduction in waste stabilization ponds. Additionally, it was observed that waste stabilization ponds, trickling filters, and UASB reactors could obtain a greater reduction in bacteria (5–7 log10) when combined with additional treatment (e.g., chemical disinfection or use of maturation ponds). Also, mechanized systems, such as activated sludge systems and membrane bioreactors, obtained a greater reduction (2–3 log10) of viruses when compared to a natural system. It was concluded that the selection of the best suitable technology for pathogen reduction depends on environmental, design, and operational factors as well as considering the performance of specific wastewater treatment systems individually as well as when combined with other treatment technologies that may provide added removal of microbial constituents.
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Corden, Thomas Joseph. "Development of design and manufacturing techniques for glass reinforced plastic waste water treatment equipment." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339665.
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Segid, Yosief Teklehaimanot. "EVALUATION OF THE TAB-SIMCO ACID MINE DRAINAGE TREATMENT SYSTEM: WATER CHEMISTRY, PERFORMANCE AND TREATMENT PROCESSES." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/203.
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Mergen, Maxime Rodolphe Denis. "Impact of magnetic resin on DOC removal and downstream water treatment processes." Thesis, Cranfield University, 2008. http://dspace.lib.cranfield.ac.uk/handle/1826/2702.
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Seasonal periods of high rainfall and changes in land management have led to difficulties for UK water companies to remove sufficient natural organic matter (NOM) to stay in compliance with the tightening trihalomethane (THMs) standards. Hence alternative treatment options have come into focus of research and development. The continuous anion exchange process based on a novel magnetic resin (MIEX® resin) has emerged as a promising method to increase NOM removal and has been compared in this thesis to the most widely spread drinking water treatment method of coagulation with hydrolysing metal salts. Therefore the removal efficiency of both processes was investigated by treating different natural waters sources as well as selected organic model compounds of different hydrophobicity and molecular weight (MW). Magnetic resin was thereby seen to be competitive with coagulation for DOC removal in low SUVA sources dominated by mid to low MW material and to outperform coagulation for the treatment of low MW, hydrophilic acids. However magnetic resin had to be used in combination with subsequent coagulation using largely reduced Fe doses to ensure high levels of DOC removal in sources dominated by high MW NOM. This was related to a physical blockage mechanism of the easily accessible external resin bead surface by this high MW material. An effect that could be reduced by applying increased resin doses, which provided a larger external surface area for DOC removal. A combination of magnetic resin treatment with coagulation was nonetheless seen to be able to increase DOC removal as well as to generate enhanced floc properties in terms of strength, settling velocity and size. Beside a reduced THM formation potential, making magnetic resin an effective tool to help meet legislative standards, an increased solid-liquid separation was seen in pilot-scale to result from these effects.
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Lin, Joseph C. (Joseph Chris) 1981. "Determining the removal effectiveness of flame retardants from drinking water treatment processes." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29411.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.Includes bibliographical references (p. 52-55).
Low concentrations of xenobiotic chemicals have recently become a concern in the surface water environment. The concern expands to drinking water treatment processes, and whether or not they remove these chemicals while going through the treatment plant. In this study, the concentrations of organophosphoric acid triester flame retardants tributyl phosphate, tri(2-chloroethyl) phosphate, and ethanol, 2-butoxy-, phosphate (3:1) were measured after major treatment processes at the Chattahoochee Drinking Water Plant in Atlanta, Georgia, USA. The findings indicated significant removal of all three organophosphate triesters after the pre-treatment chemical addition of sodium hypochlorite. The interaction of sodium hypochlorite and organophosphate triesters, through oxidation, was suspected to be the reason for the removal. Second, the concentrations of tri(2-chloroethyl) phosphate after the filtration stage and at the clearwell were much greater than values after the sedimentation stage, and were well above the concentration measured at the intake. Exposure to the chemicals within the treatment plant was the chief potential reason for the heightened concentrations.
by Joseph C. Lin.
M.Eng.
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Itle, Cortney H. "Properties of Waste Resulting from Arsenic Removal Processes in Drinking Water Treatment." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34132.
Full textAbstract:
The arsenic maximum contaminant level (MCL) for drinking water is likely to be lowered sometime in 2001 or 2002. If the MCL is lowered, it is speculated that there will be stricter limits imposed on the disposal and handling of arsenic-containing residuals. The purpose of this study is to determine the properties of drinking water residuals, including the chemical characteristics, the amount of arsenic that leaches in common residual handling and dewatering processes, and the hazardous potential of the residuals.
Residual samples were collected from seven utilities with high arsenic concentrations in their raw water. Included in the study were four plants that coagulate with ferric chloride, two with aluminum hydroxide, and one softening plant. The residuals from each facility were acid digested and chemically characterized using ICP-AES to determine the total arsenic, aluminum and iron present. TCLP and California WET were performed to verify if the residuals were hazardous.
Simulated lagoons were set up and monitored over a six-month period to determine the amount of arsenic that was leached to the liquid portion over time. Toxicity testing was performed on the residuals at 20% and 100% after two months and six months of storage. Bench-scale sand drying beds were used to dewater residuals, and the leachates were analyzed to determine if arsenic leached from residuals.
The residuals were found to contain high levels of arsenic during the chemical characterization. However, all of the facilities passed the current TCLP limit of 5 mg/L. For all residuals, the California WET values were much higher than the TCLP values.
In the lagoon study, redox potentials decreased and the arsenic and iron concentrations in the liquid portions increased. In the sand drying beds, very little arsenic leached; arsenic concentrations in the leachate were less than 10 ppb. Lagoon storage may not be a safe alternative for residuals containing arsenic. However, sand drying does not appear to present any threats.
There were differences between the toxicity tests performed at 100% solids and 20% solids in the lagoon study. Some of the values increased and others decreased. Additionally, toxicity testing conducted after lagoon aging differed from earlier toxicity testing, due to the changing soluble arsenic. These discrepancies suggest that the test results can be affected by the percent solids and age of the residuals, and specific instructions should be given for consistent residuals testing.Master of Science
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Mohammed, Fadhil Muhi. "Modelling and design of water treatment processes using adsorption and electrochemical regeneration." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/modelling-and-design-of-water-treatment-processes-using-adsorption-and-electrochemical-regeneration(204b062d-9269-4638-9697-21e4b18de6b3).html.
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This thesis describes both batch and continuous processes for water treatment by adsorption with electrochemical regeneration of the adsorbent using an airlift reactor. The process is based on the adsorption of dissolved organic pollutants onto a graphite intercalation compound (GIC) adsorbent and subsequent electrochemical regeneration of the adsorbent by anodic oxidation of the adsorbed pollutant. Batch experiments were carried out to determine the adsorption kinetics and equilibrium isotherm for a sample contaminant, the organic dye Acid Violet 17 on the GIC (Nyex®1000) adsorbent. The adsorption capacity was found to be around 1 ± 0.05 mg/g. The rate of adsorption appeared to follow pseudo-second order kinetics. The increase in the rate adsorption with temperature indicated an activation energy of around 4.2 KJ/mole, suggesting that the mechanism of adsorption was physisorption. It was demonstrated that the adsorbent could be regenerated by anodic oxidation of the adsorbed dye in a simple electrochemical cell. The GIC adsorbent recovered its initial adsorption capacity after 40 to 60 min of treatment at a current density of 10 mA/cm2, corresponding to a charge passed of 12 to 15 C/g of adsorbent. The charge passed is consistent with that expected for mineralisation of the dye suggesting that the dye was removed and destroyed with high charge efficiency. Experiments were carried out to investigate the characterisation and performance of the continuous process, where water is treated continuously in a fluidised adsorption zone and the adsorbent is circulated through a moving bed electrochemical regeneration cell. The adsorbent circulation rate, the residence time distribution (RTD) of the reactor, and water treatment performance by continuous adsorption and electrochemical regeneration were studied. The RTD behaviour could be approximated as a continuously stirred tank. It was found that greater than 90% removal at feed concentrations of up to 100 mg/L were achieved using a single pass through a large continuous treatment unit by adsorption and electrochemical regeneration with a flow rate of 0.25 L/min. In a smaller continuous treatment unit 98% removal at feed concentrations of up to 66 mg/L were achieved in a single pass with a flow rate of 0.24 L/min. Steady state and dynamic models have been developed for the continuous process performance, assuming full regeneration of the adsorbent in the moving bed electrochemical cell. Experimental data and modelled predictions (using parameters for the adsorbent circulation rate, adsorption kinetics and isotherm obtained experimentally) of the dye removal achieved were found to be in good agreement. A higher dye removal was found with a co-current PFR model, but a number of tank in series (n CSTRs) was found to give higher contaminant removal for the same total adsorption zone volume. It was also found that the predicted number of stages of batch adsorption / regeneration required to achieve 99.9% AV17 removal was halved when the adsorptive capacity of the adsorbent was doubled. Similarly the predicted number of continuous CSTR adsorption / electrochemical regeneration process units required in series to achieve 99% AV17 removal was reduced by more than two thirds when the adsorptive capacity of the adsorbent was doubled.
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Fang, Jun. "Arsenic rejection by membrane processes model development and application /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5958.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 6, 2008) Includes bibliographical references.
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Holland, Valerie Ann. "Evaluation of conventional treatment processes for removal of nitrosodimethylamine (NDMA) from drinking water /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1426067.
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Litteken, Garrett Michael. "IMPACT OF WATER TREATMENT PLANT ALUM SLUDGE RESIDUALS ON WASTEWATER TREATMENT PLANT BIOLOGICAL PROCESSES: A CASE STUDY." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2246.
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Water treatment plant (WTP) residual discharge is considered a pollutant and requires treatment to prevent negative impacts when released to the environment. As regulatory requirement becomes increasingly strict, WTPs are required to find suitable methods for the treatment of sludge residuals. Wastewater treatment plants(WWTP) provide existing treatment methods to remove contaminants from WTP residuals. A case study on the Carbondale Water Treatment Plant (CWTP) and receiving Carbondale Southeast Waste Water Treatment Plant (SEWWTP) provided an opportunity to quantify potential negative impacts for the discharge of residual alum sludge to a biologic sludge digestion plant. The first part of the study focused on quantifying changes to the SEWWTP loading conditions from the addition of metal salt coagulant water treatment residuals discharged by the CWTP. Historic sludge quantities and treatment methodologies for both the CWTP and SEWWTP were used to predict loading conditions and residual concentrations at the SEWWTP. Ammonia, BOD, pH, and TSS concentrations from the CWTP were not identified to significantly impact the existing concentrations at the SEWWTP. Metals concentrations from the CWTP were also found to fall within WWTP regulatory quantities. The second part of the study evaluated potential impacts to beneficial bacteria populations in the SEWWTP oxidation ditch from the receipt of CWTP alum residuals. Studies of residual alum sludge impacts to beneficial bacterial populations are rare, and often do not translate from one treatment plants processes to the next. The SEWWTP employs a multi-ring oxidation ditch with an anoxic outer ring and aerobic middle and inner rings. Biologic Activity Reaction Tests (BART) were used to isolate beneficial bacteria species typically present in oxidation ditches including heterotrophic aerobic bacteria, denitrifying bacteria, and nitrifying bacteria. Heterotrophic aerobic bacteria and denitrifying bacteria are the predominant beneficial bacteria species in the outer ring, while nitrifying bacteria and heterotrophic aerobic bacteria dominate the aerobic inner rings. Heterotrophic aerobic bacteria and denitrifying bacteria populations identified in the outer ring of the oxidation ditch did not demonstrate any population impacts from the receipt of residual alum sludge. In addition, nitrifying bacteria populations and heterotrophic aerobic bacteria population demonstrated no impacts from the introduction of CWTP residual alum waste to the aerobic inner ring of the oxidation ditch. Overall, the study demonstrated the treatment of residual alum sludge from a WTP is possible through the existing biological processes at a WWTP.
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Steele, Andres. "Factors impacting on the appropriateness of water treatment and supply processes for post-emergency water supply systems." Thesis, University of Surrey, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520478.
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Ghasemzadeh, Shahram M. S. "Effect of Hydraulic Fracturing Waste in Wastewater Treatment Processes." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1471254155.
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Reig, i. Amat Mònica. "Integration of electrically driven membrane separation processes for water treatment and resources recovery." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/404786.
Full textAbstract:
Nowadays, due to the growing fresh water demand, several processes are used to purify seawater by means of desalination or industrial brackish water by different treatment processes. The main limitation of these techniques is the production of rejected brines. For this reason, new management techniques for brines valorization are being studied to achieve the maximum water recovery, avoid liquid streams disposal and recover the valuable compounds from the concentrated streams. In this thesis, four membrane technologies were used to promote resources recovery, including water, depending on the valorization way of the concentrated stream: electrodialysis (ED) was used for its concentration, nanofiltration (NF) for its purification, selectrodialysis (SED) for its ions separation and ED with bipolar membranes (EDBM) for acid and base production from the brines. The integration of these membrane techniques provided brines reuse and promoted potential circular economy based on solutions where a waste is transformed into a resource.
Seawater reverse osmosis (SWRO) brine was treated by ED in order to concentrate NaCl for the chlor-alkali industry. An ED pilot plant was used to concentrate the brine up to 150-250 g NaCl/L, depending on temperature and current density conditions. Then, a mathematical algorithm was developed to predict the concentration evolution during the ED process. The model was able to describe the NaCl concentration evolution and the energy consumption taking into account temperature changes and longtime operation. Moreover, monovalent selective cationic (MVC) membranes were synthetized using several mixtures of polyvinylidene fluoride (PVDF) and sulfonated PVDF (S-PVDF). Then, surface polymerization of polyaniline (PANi) doped with p-toluene sulfonic acid (pTSA) or L-valine was applied in order to improve their cationic monovalent selectivity. Results indicated that sodium selectivity increased when using doping agents (higher sodium selectivity when using valine than pTSA) or increasing the voltage applied.
Besides, NF was used as a purification treatment for the SWRO brine. Different membrane configurations (flat sheet (FS) and spiral wound (SW)) were tested to study ions rejection behavior. The solution-diffusion-electromigration-film model (SDEFM) was successfully applied in order to fit the experimental rejections and calculate the membrane permeances to each ion. Ions rejection and permeances calculated for both membrane configurations were similar. These results indicated that lab-scale results could be used for the NF scale up. Also, the dominant salt effect on the trace ion rejection was determined by means of a FS membrane indicating that a higher initial dominant salt concentration implied a lower rejection for the dominant salt itself and also for the trace ions.
Furthermore, two ED-based technologies were used. SED was utilized to separate chloride from sulfate ions of an industrial wastewater rich in sodium chloride and sodium sulfate, achieving separation factors around 80-90 %. EDBM was employed to produce sodium hydroxide/hydrochloric acid from sodium chloride and sodium hydroxide/sulfuric acid from sodium sulfate.Finally, ED, NF and SED were used as pre-treatments for EDBM. With the NF and EDBM system it was possible to purify the SWRO brine working with NF membranes at 20 bar. However, the permeate stream was treated by chemical precipitation in order to diminish the calcium and magnesium concentration before being introduced in the EDBM system. Maximum NaOH and HCl concentrations of 1 M were obtained. ED was used prior to the EDBM in order to concentrate the SWRO brine up to 200 gNaCl/L and be able to produce 2 M acid and base. SED was used to separate chloride from sulfate ions of an industrial wastewater. Both streams, sodium chloride-rich and sodium sulfate-rich were introduced in the EDBM stack and pure sodium hydroxide, hydrochloric acid (87 %) and sulfuric acid (93 %) were produced.A causa de la creixent demanda d'aigua, s'utilitzen varis processos de membrana per purificar aigua de mar mitjançant dessalinització o bé per tractar salmorres industrials. La principal limitació d'aquestes tècniques és la producció de salmorres de rebuig. Per això, s'estudien noves tecnologies per valoritzar salmorres i aconseguir la màxima recuperació d'aigua i/o composts valuosos dels corrents concentrats. En la tesi, es van utilitzar quatre tecnologies de membrana per promoure la recuperació de recursos, incloent aigua, depenent de la forma de valorització del corrent concentrat: l¿electrodiàlisi (ED) es va utilitzar per a la seva concentració, la nanofiltració (NF) per a la seva purificació, la selectrodiàlisi (SED) per a la separació dels seus ions i l'ED amb membranes bipolars (EDBM) per a la producció d'àcid i base a partir de les salmorres. La integració d'aquestes tècniques de membrana promou la reutilització de salmorres i una potencial economia circular on un residu es transforma en recurs. La salmorra d'osmosi inversa d'aigua de mar (SWRO) va ser tractada mitjançant ED per concentrar NaCl per a la indústria clor-àlcali. Es va utilitzar una planta pilot d'ED per concentrar la salmorra fins a 150-250 gNaCl/L, depenent de la temperatura i la densitat de corrent. Es va desenvolupar un algoritme matemàtic per predir l'evolució de concentració durant l'ED. El model va ser capaç de descriure l'evolució de la concentració de NaCl i el consum energètic tenint en compte els canvis de temperatura i la llarga durada dels experiments. D'altra banda, es van sintetitzar membranes selectives a cations monovalents (MVC) usant mescles de fluorur de polivinilidè (PVDF) i PVDF sulfonat (S-PVDF). A continuació, es va aplicar una polimerització de superfície amb polianilina (PANi) dopada amb àcid p-toluè sulfònic (pTSA) o L-valina per millorar la seva selectivitat a MVC. Els resultats van indicar que la selectivitat de sodi augmentava quan s'utilitzaven agents de dopatge (major selectivitat de sodi a l`utilitzar valina enfront de pTSA) o s'augmentava el voltatge aplicat. La NF va ser usada per purificar la salmorra SWRO. Es van provar dues configuracions de membrana (plana (FS) i en espiral (SW)) per estudiar el comportament del rebuig dels ions. El model de pel·lícula de solució-difusió-electromigració (SDEFM) es va ajustar amb èxit als rebutjos experimentals i va permetre calcular les permeances de la membrana a cada ió. El rebuig dels ions i les permeances calculades per a les dues configuracions de membrana van ser similars. Per tant, els resultats a escala de laboratori es podrien utilitzar per a l'escalat de NF. A més, l'efecte de la sal dominant en el rebuig d'ions traça va ser determinada per mitjà d'una membrana FS indicant que una major concentració inicial de sal dominant implicava un menor rebuig de sal dominant i d'ions traça. També es van emprar dues tecnologies basades en l'ED. La SED es va utilitzar per separar els clorurs dels sulfats d'una aigua residual industrial, aconseguint uns factors de separació del 80-90%. L'EDBM es va usar per produir hidròxid de sodi/àcid clorhídric a partir de clorur de sodi i hidròxid de sodi/àcid sulfúric a partir de sulfat de sodi. Finalment, l'ED, la NF i la SED es van emprar com a pretractaments de l'EDBM. Amb el sistema NF-EDBM es va purificar la salmorra SWRO treballant amb membranes de NF a 20 bar. No obstant això, el permeat va ser tractat per precipitació química per disminuir la concentració de calci i magnesi abans de ser introduït a l'EDBM. Es van obtenir concentracions màximes d'NaOH i HCl de 1 M. L'ED es va usar abans de l'EDBM per concentrar la salmorra SWRO fins a 200 gNaCl/L i ser capaç de produir àcid i base 2 M. La SED es va utilitzar per separar clorurs de sulfats d'una aigua residual industrial. Ambdós corrents, el ric en clorur de sodi i el ric en sulfat de sodi, es van introduir a l'EDBM per produir hidròxid de sodi pur, àcid clorhídric (87%) i àcid sulfúric (93%).
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Chai, Ayala. "Application of neural networks to the modeling of water treatment particulate removal processes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq40919.pdf.
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Geroni, Jennifer. "Rates and mechanisms of chemical processes affecting the treatment of ferruginous mine water." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/19120/.
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This thesis presents the results of research undertaken into the rates of Fe(II) oxidation and CO2 stripping from ferruginous mine drainage. It also provides new insight into the applicability of Vertical Flow Reactors (VFRs) to the treatment circumneutral waters. Batch-wise experiments were used to determine Fe(II) oxidation rates in the field. The data collected were used to show that values for the rate constant k1 were up to 3 orders of magnitude greater at the field sites than would be predicted from previously published laboratory studies. A methodology was also developed for determining k2 (the heterogenous oxidation rate constant) in the field. The results of field based monitoring of aeration cascades as well as batchwise CO2 stripping experiments conducted using waters of varying chemistry were combined with geochemical modelling to demonstrate the evolution of the chemistry in these systems over time. The aeration cascades were shown to remove approximately 50% of the dissolved CO2 initially present but this was not shown to have an appreciable effect on mine water treatability. Continued removal of the residual CO2 fraction by mechanical aeration resulted in the elevation of pH by up to 2 units. Trials of pilot scale Vertical Flow Reactors (VFR) at two sites in South Wales showed that rapid decreases in bed permeability over time make these systems unsuitable for deployment in the treatment highly net alkaline waters. As a result of adverse weather conditions and other technical difficulties there was insufficient data collected to determine the performance of these systems under net acid conditions. Qualitative observations suggest however that Fe removal was taking place at a significantly higher rate than would be seen in settling lagoons under the same conditions.
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Boyd, Christopher. "Assessment, Optimization, and Enhancement of Ultrafiltration (UF) Membrane Processes in Potable Water Treatment." Doctoral diss., University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5909.
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This dissertation reports on research related to ultrafiltration (UF) membranes in drinking water applications. A pilot-scale investigation identified seasonal surface water quality impacts on UF performance and resulted in the development of a dynamic chemically enhanced backwash protocol for fouling management. Subsequent analysis of UF process data revealed limitations with the use of specific flux, transmembrane pressure (TMP), and other normalization techniques for assessing UF process fouling. A new TMP balance approach is presented that identifies the pressure contribution of membrane fouling and structural changes, enables direct process performance comparisons at different operating fluxes, and distinguishes between physically and chemically unresolved fouling. In addition to the TMP balance, a five component optimization approach is presented for the systematic improvement of UF processes on the basis of TMP variations. Terms are defined for assessing process event performance, a new process utilization term is presented to benchmark UF productivity, and new measures for evaluating maintenance procedures are discussed. Using these tools, a correlation between process utilization and operating pressures was established and a sustainable process utilization of 93.5% was achieved.
UF process capabilities may be further enhanced by pre-coating media onto the membrane surface. Silicon dioxide (SiO2) and powdered activated carbon (PAC) are evaluated as pre-coating materials, and the applicability of the TMP balance for assessing pre-coated membrane performance is demonstrated. The first use of SiO2 as a support layer for PAC in a membrane pre-coating application is presented at the laboratory-scale. SiO2-PAC pre-coatings successfully reduced physically unresolved fouling and enhanced UF membrane organics removal capabilities.Ph.D.
Doctorate
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Environmental Engineering
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Rossouw, Arnoux. "Modified track-etched membranes using photocatalytic semiconductors for advanced oxidation water treatment processes." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80276.
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Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The purpose of this study was to develop modi ed tract-etched membranes using nanocomposite TiO2 for advanced water treatment processes. Photocatalytic oxidation and reduction reactions take place on TiO2 surfaces under UV light irradiation, therefore sunlight and even normal indoor lighting could be utilised to achieve this effect. In membrane ltration, caking is a major problem, by enhancing the anti-fouling properties of photocatalysts to mineralise organic compounds the membrane life and e ciency can be improved upon. In this study the rst approach in nanocomposite membrane development was to directly modify the surface of polyethylenetherephthalate (PET) track-etched membranes (TMs) with titanium dioxide (TiO2) using inverted cylindrical magnetron sputtering (ICMS) for TiO2 thin lm deposition. The second approach was rst to thermally evaporate silver (Ag) over the entire TM surface, followed by sputtering TiO2 over the silver-coated TM. As a result a noble metal-titania nanocomposite thin lm layer is produced on top of the TM surface with both self-cleaning and superhydrophilic properties. Reactive inverted cylindrical magnetron sputtering is a physical vapour deposition method, where material is separated from a target using high energy ions and then re-assimilated on a substrate to grow thin lms. Argon gas is introduced simultaneously into the deposition chamber along with O2 (the reactive gas) to form TiO2. The photocatalytic activity and other lm properties, such as crystallinity can be in uenced by changing the sputtering power, chamber pressure, target-to-substrate distance, substrate temperature, sputtering gas composition and ow rate. These characteristics make sputtering the perfect tool for the preparation of di erent kinds of TiO2 lms and nanostructures for photocatalysis. In this work, the utilisation of ICMS to prepare photocatalytic TiO2 thin lms deposited on track-etched membranes was studied in detail with emphasis on bandgap reduction and TM surface regeneration. Nanostructured TiO2 photocatalysts were prepared through template directed deposition on track-etched membrane substrates by exploiting the good qualities of ICMS. The TiO2-TM as well as Ag-TiO2-TM thin lms were thoroughly characterised. ICMS prepared TiO2 lms were shown to exhibit good photocatalytic activities. However, the nanocomposite Ag-TiO2 thin lms were identi ed to be a much better choice than TiO2 thin lms on their own. Finally a clear enhancement in the photocatalytic activity was achieved by forming the Ag-TiO2 nanocomposite TMs. This was evident from the band-gap improvement from 3.05 eV of the TiO2 thin lms to the 2.76 eV of the Ag-TiO2 thin lms as well as the superior surface regenerative properties of the Ag-TiO2-TMs.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om verbeterde baan-ge etste membrane (BMe) met behulp van nano-saamgestelde titaandioksied (TiO2) vir gevorderde water behandeling prosesse te ontwikkel. Fotokatalitiese oksidasie- en reduksie reaksies vind plaas op die TiO2 oppervlaktes onder UV-lig bestraling, en dus kan sonlig en selfs gewone binnenshuise beligting gebruik word om die gewenste uitwerking te verkry. In membraan ltrasie is die aanpaksel van onsuiwerhede 'n groot probleem, maar die verbetering van die self-reinigende eienskappe van fotokatalisators deur organiese verbindings te mineraliseer, kan die membraan se leeftyd en doeltre endheid verbeter word. In hierdie studie was die eerste benadering om nano-saamgestelde membraan ontwikkeling direk te verander deur die oppervlak van polyethylenetherephthalate (PET) BMe met 'n dun lagie TiO2 te bedek, met behulp van reaktiewe omgekeerde silindriese magnetron verstuiwing (OSMV).Die tweede benadering was eers om silwer (Ag) termies te verdamp oor die hele BM oppervlak, gevolg deur TiO2 verstuiwing bo-oor die silwer bedekte BM. As gevolg hiervan is 'n edelmetaal-titanium nano-saamgestelde dun lm laag gevorm bo-op die oppervlak van die BM, met beide self-reinigende en verhoogde hidro liese eienskappe. OSMV is 'n siese damp neerslag metode, waar materiaal van 'n teiken, met behulp van ho e-energie-ione, geskei word, en dan weer opgeneem word op 'n substraat om dun lms te vorm. Argon gas word gelyktydig in die neerslag kamer, saam met O2 (die reaktiewe gas), vrygestel om TiO2 te vorm. Die fotokatalitiese aktiwiteit en ander lm eienskappe, soos kristalliniteit, kan be nvloed word deur die verandering van byvoorbeeld die verstuiwingskrag, die druk in die reaksiekamer, teiken-tot-substraat afstand, substraattemperatuur, verstuiwing gassamestelling en vloeitempo. Hierdie eienskappe maak verstuiwing die ideale hulpmiddel vir die voorbereiding van die verskillende soorte TiO2 lms en nanostrukture vir fotokatalisasie. In hierdie tesis word OSMV gebruik ter voorbereiding van fotokatalitiese TiO2 dun lms, wat gedeponeer is op BMe. Hierdie lms word dan in diepte bestudeer, met die klem op bandgaping vermindering en BM oppervlak hergenerasie. Nanogestruktureerde TiO2 fotokataliste is voorberei deur middel van sjabloongerigte neerslag op BM substrate deur die ontginning van die goeie eienskappe van OSMV. Die TiO2-BM dun lms, sowel as Ag-TiO2-BM dun lms, is deeglik gekarakteriseer. OSMV voorbereide TiO2 dun lms toon goeie fotokatalitiese aktiwiteite. Nano-saamgestelde Ag-TiO2 dun lms is egter ge denti seer as 'n veel beter keuse as TiO2 dun lms. Ten slotte is 'n duidelike verbetering in die fotokatalitiese aktiwiteit bereik deur die vorming van die Ag-TiO2 nano-saamgestelde BMe. Dit was duidelik uit die bandgapingverbetering van 3,05 eV van TiO2 dun lms in vergelyking met die 2,76 eV van Ag-TiO2 dun lms. 'n Duidelike verbetering is behaal in die fotokatalitiese aktiwiteit deur die vorming van die Ag-TiO2 nano-saamgestelde TMs.
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Malcolm, Watson. "The removal of arsenic during drinking water treatment by sorption and coagulation processes." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2016. https://www.cris.uns.ac.rs/record.jsf?recordId=101128&source=NDLTD&language=en.
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This dissertation investigates the factors which affect the removal of arsenic from groundwater by adsorption and coagulation technologies, including the interactions between As and natural organic matter (NOM). Humic acid (HA) was utilised as an NOM analogue, and was shown to be capable of both complexing and oxidising As, depending upon the prevailing conditions. The arsenic removing capabilities of three iron oxide coated sands (IOCS) were investigated, including IOCSW, a waste material from a local drinking water treatment plant generated during the removal of iron and manganese. IOCSW was highly effective at removing both As(V) and As(III) from synthetic water matrices (qmax = 78.3 µg As(V)/g and 99.1 µg As(III)/g). The negative effects of competitive anions (phosphates, silicates and HA) on arsenic removals were not significant enough to preclude the application of IOCSW for arsenic removal during drinking water treatment. The removals of both As and NOM by coagulation and enhanced coagulation with pH correction and preoxidation were also investigated. As(V) was more readily removed by coagulation than As(III), so that the most efficient coagulation treatment investigated for arsenic and NOM removal applied preozonation with subsequent combined coagulation with polyaluminium chloride and ferric chloride. Different groundwaters displayed large variations in the As and NOM removal behaviours. Response surface methodology (RSM) was therefore applied to investigate the interactions between As and NOM during ferric chloride coagulation and optimise their combined removals. Multiple interaction effects were observed during this investigation, highlighting the importance of utilizing RSM to optimise drinking water treatment technologies.Ova disertacija ispituje faktore koji utiču na uklanjanje arsena iz podzemne vode primenom adsorpcija i koagulacije, uključujući i interakcije između arsena i prirodnih organskih materija (POM). Huminska kiselina (HA) je korisćena kao model za POM, a pokazano je da može i da kompleksira i da oksiduje As, u zavisnosti od eksperimentalnih uslova. Ispitivane su mogućnosti uklanjanja arsena za tri peska obložena gvožđe oksidom (IOCS), uključujući IOCSW, koji je dobijen sa postrojenja za tretman vode za piće i potiče iz procesa uklanjanja gvožđa i mangana. IOCSW se pokazao kao visoko efikasan za uklanjanje As(V) i As(III) iz sintetičkih vodenih matriksa (qmax = 78.3 µg As(V)/g i 99.1 µg As(III)/g). Negativni efekti kompetirajućih jona (fosfata, silikata i HA) na uklanjanje arsena nisu bili dovoljno značajni da bi se isključila primena IOCSW za uklanjanje arsena tokom tretmana vode za piće. Zajedničko uklanjanje As i POM koagulacijom i unapređenom koagulacijom uz podešavanje pH i kombinovanje sa oksidacionim predtretmanima je takođe ispitivano. Bolje uklanjanje koagulacijom postignuto je za As(V) u odnosu na As(III), stoga se kao najefikasniji ispitivani koagulacioni tretman pokazalo uklanjanje arsena i POM primenom predozonizacije praćene kombinovanom koagulacijom sa polialuminijum hloridom i gvožđe hloridom. Ispitivanja na različitim podzemnim vodama, pokazala su velike varijacije u ponašanju As i POM tokom tretmana. Iz tog razloga je primenjena metodologija odzivne površine (RSM) u cilju ispitivanja interakcija između As i POM tokom koagulacije gvožđe hloridom i optimizacije njihovog kombinovanog uklanjanja. Sagledavanje većeg broja interakcija primenom metodologije odzivne površine potvrđuje važnost njegove primene pri optimizaciji tretmana vode za piće.
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Khalid, Muhammad Imran. "Development of an intelligent dynamic modelling system for the diagnosis of wastewater treatment processes." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1153.
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In the 21st Century, water is already a limited and valuable resource, in particular the limited availability of fresh water sources. The projected increase in global population from 6 billion people in 2010 to 9 billion in 2050 will only increase the need for additional water sources to be identified and used. This situation is common in many countries and is frequently exacerbated by drought conditions. Water management planning requires both the efficient use of water sources and, increasingly, the re-use of domestic and industrial wastewaters. A large body of published research spanning several decades is available, and this research study looks specifically at ways of improving the operation of wastewater treatment processes.Process fault diagnosis is a major challenge for the chemical and process industries, and is also important for wastewater treatment processes. Significant economic and environmental losses can be attributed to inappropriate Abnormal Event Management (AEM) in a chemical/processing operation, and this has been the focus of many researchers. Many researchers are now focusing on the application of several fault diagnosis techniques simultaneously in order to improve and overcome the limitations experienced by the individual techniques. This approach requires resolution of the conflicts ascribed to the individual methods, and incurs additional costs and resources when employing more than one technique. The research study presented in this thesis details a new method of using the available techniques. The proposal is to use different techniques in different roles within the diagnostic approach based upon their inherent individual strengths. The techniques that are excellent for the detection of a fault should be employed in the fault detection, and those best applied to diagnosis are used in the diagnosis section of a diagnostic system.Two different techniques are used here, namely a mathematical model and data mining are used for detection and diagnosis respectively. A mathematical model is used which is based upon the principal of analytical redundancy in order to establish the presence of a fault in a process (the fault detection), and data mining is used to produce production rules derived from the historical data for the diagnosis. A dataset from an industrial wastewater treatment facility is used in this study.A diagnostic algorithm has been developed that employs the techniques identified above. An application in Java was constructed which allows the algorithm to be applied, eventually producing an intelligent modelling agent. Thus the focus of this research work was to develop an intelligent dynamic modelling system (using components such as mathematical model, data mining, diagnostic algorithm, and the dataset) for simulation of, and diagnosis of faults in, a wastewater treatment process where different techniques will be assigned different roles in the diagnostic system.Results presented in Chapter 5 (section 5.5) show that the application of this combined technique yields better results for detection and diagnosis of faults in a process. Furthermore, the dynamic update of the set value for any process variable (presented in Chapter 5, section 5.2.1) makes possible the detection of any process disturbance for the algorithm, thereby mitigating the issue of false alarms. The successful embedding of both a detection and a diagnostic technique in a single algorithm is a key achievement of this work, thus reducing the time taken to detect and diagnose a fault. In addition, the implementation of the algorithm in the purposebuilt software platform proved its practical application and potential to be used in the chemical and processing industries.
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Harianto, Rina. "Design of a Novel Thin Film Reactor for Photocatalytic Water Treatment Process." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1604335732713241.
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You, Chen Xialei. "Nutrient recovery from waste water treatment plant by sorption processes : technical and economic analysis." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/664193.
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In the last years has been performed a huge number of research related to nutrients (mainly N and P) recovery from waste water in order to promote their reuse and also to avoid eutrophication. Recovering nutrient from waste water can promote the circular economy, minimize the environmental footprint of waste water treatment and reduce anthropogenic alteration of nitrogen and phosphorus natural cycle.
Among the different techniques studied, sorption is nowadays one of the most interesting alternatives as requires less energy than electrochemical or membrane technologies and sorbents can be regenerated for being reused. Thus, the overall sorption performance of different ion exchangers was characterized for nutrient recovery from waste water treatment plant effluents.
Two commercial polymeric resins doped with Hydrated Ferrous Oxide (HFO) (Lewatit FO36 and Fiban-As) were assessed for ammonium and phosphate uptake from waste water streams. Equilibrium and kinetics studies have been performed through batch experiments and the dynamic studies were carried out by fixed-bed column. The experimental study covered from the simplest monocomponent synthetic water (ammonium, phosphate solutions) to the most complex real water from waste water treatment plant (WWTP) which contains ions, TSS and organic matter.
Sorption experiments reported for both sorbents high selectivity towards phosphate ions as sorption capacity did not significantly decrease in presence of competing ions. Loaded sorbents were regenerated through alkaline and acid desorption in order to reuse resin and obtain a high concentrated phosphate solution, which could be used for high quality fertilizer production. Results in dynamic flow experiments reported up to 80% of loaded phosphate extraction, although during desorption process was observed sorption capacity decrease up to 30% after three sorption-desorption working cycles.
Besides, salt modified synthetic zeolites were assessed for being used both as one charge (di-valent forms) and reusable (mono-valent forms) sorbent. Raw zeolites provided in sodium form as well as it modification in potassium form showed high sorption capacity for ammonium uptake but poor performance for phosphate recovery from waste water streams as the sorption mechanism is mainly ion exchange. Regeneration experiments showed that both Ze-Na and Ze-K can be reused several sorption-desorption working cycles without significant sorption capacity decrease (< 5%).
Nevertheless, after salt modification to calcium and magnesium forms, the precipitation of phosphate salts was favoured obtaining hydroxyapatite and struvite in loaded Ze-Ca and Ze-Mg, respectively. As hydroxyapatite’s solubility and phosphorus availability is similar to commercial fertilizers, loaded Ze-Ca could be potentially recycled for agricultural uses.
Finally, an economic assessment simulation was performed by applying Ze-Ca in the Baix Llobregat Waste Water Treatment Plant, located in the Metropolitan Area of Barcelona. The study reported that the implantation Ze-Ca filtration for nutrient recovery would be economically feasible, despite that more research is required in order to fit technical issues as the loaded sorbent disposal or the capability of loaded zeolites to be used as fertilizer.En los últimos años se han llevado a cabo un gran número de estudios relacionados con la recuperación de nutrientes (sobre todo N y P) de aguas residuales con el fin de promover su reutilización y evitar la eutroficación . Recuperar nutrientes de aguas residuales puede promover la economía sircular , minimizar la huella de los tratamientos de aguas residuales, así como reducir la alteración antropogénica del ciclo natural del nitrógeno y el fósforo. Entre las diferentes técnicas estudiadas, la sorción es actualmente uno de las alternat ivas más Interesantes ya que requiere menos energía que técnicas electróquímicas o las tecnologías de membrana. Además , los sorbentes se pueden regenerar y reutilizar. Así , se ha caracterizado el comportamiento integral de diferentes sorbentes para la recuperación de nutrientes de efluentes de aguas residuales. Se evaluaron dos lntercambiadores iónicos poliméricos comerciales dopados con Óxido de Hierro Hidratado (Lewatit F036 y Fiban-As) para la eliminación de fosfato de corrientes de aguas residuales. Se llevaron a cabo estudios en equilibrio y se caracterizó la cinética mediante experimentos en discontinuo y los experimentos dinámicos se llevaron a cabo mediante columnas de lecho fijo . El estudio experimental cubrió desde soluciones monocomponentes de fosfato hasta corrientes reales de plantas de tratamiento de aguas residuales que contenían iones competidores, sólidos suspendidos y materia orgánica . Los experimentos reportaron para los dos sorbentes una alta selectividad hacia los iones fosfato, ya que no se observó una reducción significativa de la capacidad de sorción en presencia de iones competidores . Los sorbentes cargados se regeneraron mediante desorción alcalina y ácida para reutilizar el sorbents y obtener corrientes con alta concentración de fosfato, que se pueden emplear para la producción de fertilizante de alta calidad. Los resultados en columnas de lecho fijo mostraron una extracción de más del 80% del fosfato sorbido, aunque durante el proceso de desorción se vio una reducción de la capacidad de más del 30% tras tres ciclos de sorción - desorción. Además, se evaluaron zeolitas modificadas mediante tratamiento salino para ser usados tanto como sorbentes de una sola carga (en la forma divalente) como reusables (en la forma monovalente). La zeolita bruta facilitada en la forma sódica, así como la forma potásica mostraron alta capacidad para la eliminación de amonio, pero prácticamente nula capacidad de retención para los iones fosfato, ya que el mecansmo de sorción es principalmente intercambio iónico. Los experimentos de regeneración mostraron que ambas zeolitas se pueden emplear para un gran número de ciclos de sorción-desorción sin perder capacidad (<5%). Tras la modificación salida a las formas cálcica y magnésica, se favorece la precipitación de sales fosfóricas obteniendo hidroxiapatita y estruvita en la Ze-Ca y Ze-Mg cargada, espectivamente. Dada que la solubilidad de la hidroxiapatita, así como la disponibilidad del fósforo de la hidroxiapatita es similar a la de los fertilizantes comerciales, la Ze-Ca cargada puede potencialmente ser reciclado para usar en agricultura. Finalmente, se llevó a cabo una simulación económica empleando Ze-Ca en la Planta de Tratamiento de Aguas Residuales de El Baix Llobregat, situada en la Area metropolitana de Barcelona. El estudio reveló que la implantación de un filtro de Ze-Ca para la recuperación de nutrientes puuede ser económicamente viable , aunque se requieren más estudios para dar solución a aspectos técnicos como la gestión del sorbente cargado o la capacidad real de las zeolitas cargas de ser utilizadas como fertilizantes
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Arjmandi, Parvin Arjmandi. "MULTI-OBJECTIVE OPTIMIZATION OF CORE WATER TREATMENT PROCESSES INCORPORATING ULTRAVIOLET AND FLUORESCENCE SPECTROSCOPIC MEASUREMENTS." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1501345847002254.
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Trahern, Patti Gremillion. "A comparative study of freeze-thaw processes for conditioning wastewater and water treatment sludges." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/53845.
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This research effort involved the application of indirect- and direct-contact, freeze-thaw conditioning techniques for improving the dewatering characteristics of both wastewater and water treatment sludges. Sludges tested included waste activated sludge, primary sewage sludge, waste activated/primary sewage sludge mixtures and alum sludge. The direct-freeze methods examined were the use of a secondary refrigerant (butane) evaporated in the sludge and the use of gas hydrate or clathrate formation by addition of Freon 12 under appropriate temperature and pressure conditions. Sludges were also frozen solid using indirect freezing methods, thawed and tested for comparative purposes. Particle size distribution and floc density measurements were used to determine changes in particle characteristics; specific resistance values and dewatered dry solids concentration were used to assess dewatering characteristics. Results of direct- and indirect-contact, freeze-thaw conditioning were compared to the effects of polymer conditioning. The results indicated that direct-freeze methods do not appear technically or economically competitive with currently accepted conditioning methods. The superior results obtained with the indirect-contact, freeze-thaw process when compared to the direct-contact processes suggested that the extent and rate of freezing may greatly influence the particle characteristics of the conditioned sludge, and thus its dewatering characteristics.Ph. D.
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Hutton, Mirinda. "Evaluation of pressure-driven and novel membrane processes for treatment of cooling tower water." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464440.
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Mukiibi, Muhammed Mutyaba. "Arsenic Stability In Fresh and Aged Amorphous Ferric Hydroxide Sludges Generated from Brine Treatment Processes." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/194140.
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Using Environmental Protection Agency occurrence and concentration data, it is estimated that about 6 million pounds of arsenic-bearing residuals (ABSR) will be generated annually in the United States when full compliance with the new standard for arsenic in drinking water (10 μg/L) is realized. Effective management of disposal of ABSR requires both a full characterization of the materials and an understanding of the environment in which the disposal will occur. Currently, there are different testing methods to evaluate the stability of ABSR, the principal of which is the EPA Toxicity Characteristics Leaching Procedure (TCLP). These tests indicate that common ABSRs may be disposed in mixed-solid waste landfills. However, this and previous work shows that these testing methods may significantly underestimate the degree and mechanism of arsenic mobilization from the residuals, because critical physical and chemical dissimilarities exist between the tests and landfill conditions. In addition, no current testing methods simulate the mineralogic aging in those ABSR, which exhibit further complexity. Landfill disposal involves liquid and solid residence times on the order of months and decades, respectively, whereas leaching tests are completed in two days or less. Consequently, time dependent re-mineralization of residuals that would be routinely expected in landfill time scales is not addressed by standard leaching tests. Treating arsenic brines by co-precipitation with iron oxyhydroxides is an established and effective remediation method for small quantities of highly concentrated liquid arsenic waste, such as brines derived from mine tailings, ion exchange resin regeneration, and reverse osmosis treatment of drinking water. However, amorphous ferric hydroxide (AFH) is expected to exhibit mineralogical aging analogous to the observed natural evolution of ferrihydrite to goethite and hematite. The aim of this research is to develop methods for characterization of AFH sludges precipitated from concentrated arsenic brines which exhibit mineralogical aging and to evaluate the impact of such aging on arsenic leachability. Overall, aging the sludge resulted in consistently higher arsenic release.
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Greetham, Matthew. "The effect of water treatment processes on the corrosion and biofilm growth promoting properties of water within distribution systems." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339892.
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