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Published: 6 September 2023

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1

Buck, Andrew. "Characterisation of chemical processes operating within a biological wastewater treatment plant." Thesis, Open University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409874.

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2

Tjernström, Linnéa. "Function of soil-based on-site wastewater treatment systems - Biological and chemical treatment capacity." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210716.

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On-site wastewater treatment systems are among the main Swedish anthropogenic sources of nutrients causing euthropication of the Baltic Sea. Among on-site systems in Sweden almost half have septic tank treatment followed by a soil-based system, in which the wastewater is treated through soil filtration. In this study a soil based technique for on-site wastewater treatment is studied where wastewater is filtered through a sand filter. Composite samples of influent and effluent at two sand filters in the area of Stockholm are sampled to determine their chemical and biological function and to compare their treatment capacity to requirements. Parameters within the scope of the study are tot-P, NH4-N, DOC, pH, turbidity and dissolved oxygen. Biological function was considered to be good in both systems as nitrification was high and the effluent had sufficient levels of dissolved oxygen suggesting aerobic conditions. Prevailing aerobic conditions in the sand filters would also indicate good reduction of organic substances which is the case for DOC as it was reduced by above 85 % for one site and almost 70 % for the other site. The overall high reduction of organic micropollutants in the systems, reported in another study, also suggests that biological function when it comes to reduction of organic substances is good. On the other hand, chemical function, with respect to reduction of phosphorus, was not sufficient as none of the systems fulfilled the requirements from HaV for normal or high protection level. In the systems tot-P was reduced by 42 and 54 % respectively. A drawback with the method approach used in the study is that the obtained reduction results only can represent the actual situation if variations in incoming and outgoing flow, variations in influent concentrations and magnitude of dilution of effluent compared to daily wastewater load are small. As these are unknown in this case it adds uncertainty to the results.
Decentraliserade system för rening av avloppsvatten är bland de huvudsakliga svenska antropogena källorna till näringsämnen som bidrar till övergödning av Östersjön. Bland decentraliserade system i Sverige är nästan hälften system med slamavskiljare följt av ett markbaserat system i vilket avloppsvattnet renas genom infiltration i jord. I denna studie studeras en markbaserad teknik i vilken avloppsvattnet filtreras genom sand, en så kallad markbädd. En fältundersökning gjordes där samlingsprov av ingående och utgående avloppsvatten togs på två markbäddar i Stockholmsområdet för att bestämma deras biologiska och kemiska reningsfunktion samt att jämföra avskiljningen av fosfor i systemen med rekommendationer från HaV. Parametrar som inkluderats i studien är totalfosfor, ammonium-kväve, löst organiskt kol, pH, turbiditet och löst syre. Biologisk funktion ansågs bra i båda markbäddarna eftersom nitrifikationen var hög och utgående vatten hade tillräckliga halter av löst syre vilket implicerar att markbäddarna var väl syresatta. Rådande syrerika förhållanden i markbäddarna antyder också att organiskt material bryts ned avsevärt, vilket är fallet för löst kol som reducerades med mer än 85 % i en av markbäddarna och med nästan 70 % i den andra. Den höga reduktionen av organiska mikroföroreningar som påvisats i markbäddarna i en annan studie tyder också på att biologisk funktion med avseende på avsklijning av organiska substanser är bra. Kemisk funktion, med avseende på avskiljning av totalfosfor, var inte tillräcklig då ingen av markbäddarna levde upp till reduktionskraven från HaV för normal eller hög skyddsnivå. Totalfosfor avskiljdes med 42 respektive 54 % i markbäddarna. En nackdel med metoden som användes i studien är att de resultat som fåtts för avkiljning av de olika parametrarna endast kan representera den verkliga situationen om variationer i in- och utgående flöde samt variationer i ingående vattenkoncentrationer är små och om utspädningseffekten av utgående vatten är försumbar.
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3

Gamez, Grijalva Victor Manuel. "BIOLOGICAL AND PHYSICAL-CHEMICAL METHODS FOR TREATMENT OF SEMICONDUCTOR MANUFACTURING EFFLUENTS." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195838.

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Semiconductor manufacturing is one of the most advancing, growing and evolving industries. The production of semiconductors presents several challenges, both technologically and environmentally. The amount and complexity of the chemical substances utilized in the manufacturing process has been growing exponentially, and new chemicals are often introduced to the process and the environment. Two steps of this process play a special important role in the introduction of new chemical and demand of natural resources: Chemical Mechanical Planarization (CMP) and Photolithography.Wastewaters from the semiconductor manufacturing are complex and have several chemicals in different concentrations. Heavy metals, acids, chelators, surfactants and other chemicals are found in semiconductor effluents. Part of the scope of this study is to evaluate and remediate wastewaters produced in semiconductor manufacturing.During the development of this project it was found that copper can be successfully removed and recovered from CMP wastewaters by the use of a sulfate reducing bioreactor and a crystallization reactor, promoting precipitation of copper sulfides on the surface of silica sand. High removal and recovery efficiencies were found as result of the study. Another finding include that citrate is a readily biodegradable compound which can be successfully utilized as electron donor for anaerobic processes such as methanogenesis and sulfate reductions. However other important chelator, like EDTA, can cause toxicity to these microorganisms and affect important biological processes. PFOS is an important chemical for the semiconductor industry; however, the physical and chemical properties make this compound persistent in the environment and bioaccumulative. New substitutes for PFOS were tested and evaluated for their environmental impact. It was found that perfluorination plays an important role in the chemical properties of PFOS and removal of this characteristic improves the environmental performance of the new substitutes. Evaluation of these new chemicals was also performed by simulation and modeling. The software utilized in this study identified properties like toxicity and octanol-water partition coefficient accurately. On the other hand biodegradability was poorly estimated and new models are suggested for evaluation of this property for compounds with characteristics similar to the ones studied here (specifically high fluorination).
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4

Sudarjanto, Gatut. "Integrated chemical and biological treatment process to remove colour compounds from wastewater /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19717.pdf.

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5

Kramadhati, Narahari Narasiah. "The impact of aircraft deicing wastes on the biological wastewater treatment process /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100640.

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In order to ensure aircraft safety during winter conditions, glycol-based deicing and anti-icing fluids are employed prior to takeoff. These products can exert a severe impact on the environment if allowed to go untreated. The present study is related to the treatment of glycol-contaminated wastewaters by the activated sludge process.
The specific objectives of the research were to: (1) determine the effects of process parameters such as biomass concentration, deicing fluid concentration and temperature on the biodegradation kinetics. (2) determine the mechanism of deicing fluid removal and model the reaction rates. (3) determine the effects of microbial changes on the treatment process. (4) evaluate the advantages of a sequencing batch reactor for the treatment of deicing wastes. (5) corroborate our laboratory results with field data from an operating wastewater facility treating deicing wastes.
The results from the field show that despite the increases in influent organic matter during the deicing season, there were very little changes in effluent values of organic matter. Furthermore, influent concentrations of deicing fluid between 10 and 30 mg/L were reduced to trace amounts (i.e. below 5 mg/L) throughout the deicing season. However, as witnessed by the high sludge volume index during the deicing season, the presence of deicing fluid creates settling problems in the clarifier.
The laboratory batch experiments indicate optimal substrate removal rates at biomass concentrations of 1000 mg/L and 2000 mg/L. Very low biomass levels lead to inhibition whereas a high biomass level of 3000 mg/L is unnecessary since the food to microorganism ratio is such that only a fraction of the biomass participates in the degradation reaction. With regards to deicing fluid concentration, organic matter removal rates tend to increase as the deicing fluid is increased. However, at the highest level of deicing fluid, certain inhibitory effects are present. As expected, higher temperatures produce much higher removal rates with the ethylene glycol substrate showing less variation with temperature than the other organic compounds present in the wastewater.
With regards to the mechanism of removal, the results showed very little adsorption of organic matter onto the biomass within the first hour of contact. In addition, the total organic matter removal (TOC and COD) followed first order kinetics with respect to substrate concentration.
Lastly, sequencing batch reactor operation allowed for much higher removal rates as the microbial population is acclimatized to the substrate with increasing cycles. With regards to the microbial population, the Biolog results showed that there was a decrease in the variety of compounds that could be degraded as the biomass was exposed to the deicing fluid. Furthermore, most population changes occurred at the very beginning of the deicing season and in the first half of the SBR experiments.
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6

Carini, Diane. "Treatment of industrial wastewater using chemical-biological sequencing batch biofilm reactor (SBBR) processes /." [S.l.] : [s.n.], 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13431.

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7

Kordi, Javad. "Processes and drivers of biological and chemical Phosphorus removal in wastewater treatment plants." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-38814.

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Phosphorus (P) is one of the most important elements exists in wastewater in soluble forms. Several methods have been using for P recovery in wastewater treatment plants, but this study tried to investigate on the most important drivers and the processes of biological phosphorus removal (EBPR) and chemical phosphorus removal that are the major technics of P recovery globally. It has been considered that EBPR is a high recovery method (normally greater than 90%) which could be implemented in different regimes with the integration feasibility of different methods, while chemical precipitation is a flexible technique that could be dosed in various section of a treatment unit. The performance and drivers of three metal-based salts such as Iron (Fe), Aluminum (Al), and Calcium (Ca) also investigated during chemical precipitation. The crystallization process is also investigated as a subcategory model of chemical P removal method. It has been considered that the alkaline pH of 9-9.5, mixing intensity, and the addition of isomorphic seed materials are the most important factors in the crystallization process.
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8

Yan, Qingmei, and 嚴慶梅. "Biological nitrogen removal of saline wastewater by ammoniumoxidizers." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42182116.

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9

Zhao, Kang, and 趙鈧. "An iron-facilitated chemical and biological process for phosphorus removal and recovery during wastewater treatment." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196027.

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Phosphorus (P) is an important pollutant of concern in wastewater that causes eutrophication and algal blooms in water body. On the other hand, P is a valuable natural resource for agricultural and industrial use. With the rapid depletion of mineral phosphorus on earth, there is a need to recover phosphorus from wastewater. In this study, a new chemical and biological process facilitated with iron dosing has been developed for P removal and recovery during wastewater treatment. The system consists of a main stream identical to the conventional activated sludge process in an aerobic sequencing batch reactor (SBR) for P removal and a side stream of sludge recirculation through an anaerobic SBR (AnSBR) for P release and recovery from the P-rich sludge. In the aerobic SBR treating a synthetic domestic wastewater, Fe(III) (FeCl3) was dosed to remove P by precipitation and adsorption. Fe(III) dosing at a Fe/P molar ratio of 1.5:1 could reduce the P concentration from more than 10 mg/L to below 1 mg/L in the final effluent. Compared to other dosing periods, dosing Fe(III) right before the SBR settling could achieve the best result in sludge flocculation and P removal. Meanwhile, organic removal was well maintained as 90% of the chemical oxygen demand (COD) was degraded in the aerobic SBR. In the AnSBR, phosphate precipitated with ferric iron in the sludge was released owing to microbial Fe(III) reduction, and a positive correlation was found between the phosphate and ferrous iron concentrations in the sludge suspension. Chemical tests showed that significant P release from Fe(III)-P occurred only if the acidic condition and the reducing condition were combined. For the AnSBR sludge, a higher organic loading, lower pH and higher biomass concentration resulted in a higher level of Fe(III) reduction and P release. Organic acidogenesis prevailed in the reactor and lowered the pH to ~4.5, which facilitated the P release from the solid phase into the liquid phase. With a solids retention time (SRT) of 10 days, the anaerobic supernatant contained a phosphate concentration of up to 70 mg/L, while the settled sludge was returned to the aerobic SBR. The phosphate could be readily recovered from the supernatant with Fe-induced precipitation by aeration and pH adjustment, and the overall P recovery could be achieved at about 70%. In addition to the treatment performance, the speciation of P in the aerobic sludge and the anaerobic sludge also was investigated. A significant change in the immediately available P and the redox-sensitive P was found in the sludge through the aerobic-anaerobic cycle. Such chemical transformation is believed to be crucial to the P removal and recovery during the wastewater treatment process.
published_or_final_version
Civil Engineering
Master
Master of Philosophy
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10

Bailey, Andrew Douglas. "An exploratory investigation of crossflow microfiltration for solid/liquid separation in biological wastewater treatment." Master's thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/21915.

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This thesis contains the results and discussion of an exploratory investigation into the application of Crossflow Microfiltration (CFMF) for solid/liquid separation in biological wastewater treatment systems. The principal objective of the study was to assess the influence of CFMF on the performance of identified biological wastewater treatment systems. It was not the objective to optimise filtration performance. A literature review indicated that the crossflow mode of filtration has been widely accepted as a unit operation in the fermentation industry. The filtration mode is now being applied not only for solid/liquid separation but also for separations on a molecular and ionic level. Very few applications of crossflow filtration in the context of biological wastewater treatment solid/liquid separation are reported in the literature. The reasons for this limited experience would appear to be the scale involved and the perceived high costs; separations in the fermentation industry are usually conducted at relatively small scale (laboratory or pilot-scale) and involve high-value products, justifying high capital and operating costs. Also, the high level of separation performance attained is perhaps not necessary for many wastewater treatment applications. No doubt these reservations are largely valid. However, these arguments cannot be applied equally to all filtration methods and wastewater treatment schemes. For example, the costs of microfiltration are substantially less than ultrafiltration or reverse osmosis, and in certain cases effluents with extremely low suspended solids contents may be required. In the light of these observations an investigation of CFMF for solid/liquid separation in biological wastewater treatment systems appears justified. Two biological treatment systems were selected for study: the Upflow Anaerobic Sludge Bed (UASB) reactor and the Activated Sludge system. The envisaged benefits accruing from the application of CFMF were different in each case.
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11

Musvoto, Eustina Vongai. "Mathematical modelling of integrated chemical, physical and biological treatment of wastewaters." Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/9676.

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Includes bibliographical references.
The development of a kinetic-based model to simulate chemical, physical and biological processes in three phase (gaseous-aqueous-solid) mixed weak acid/base systems is described. The chemical processes are expressed in terms of the kinetics of the forward and reverse reactions for the dissociation of the weak acid/bases. In this approach the H⁺ and all the species of the weak acidfbases of interest are included and the pH is calculated directly from H⁺ via pH = -log (H⁺). The advantage of this approach over the alkalinity/equilibrium chemistry approach is that kinetics are used throughout. Also, the approach is general and can be applied to any combination of mixed weak acid/base systems. The kinetic expressions of the carbonate, phosphate, ammonia, acetate and water systems, including the kinetics of the three phase chemical processes viz. precipitation/dissolution of calcium and magnesium phosphates and carbonates and gas stripping/dissolution of O₂, CO₂ and NH₃, were programmed into the AQUASIM shell package to generate simulation results. The chemical processes part of the model was validated by comparing steady state model predictions with those obtained from equilibrium chemistry based models such as STASOFT I and III (Loewenthal et al., 1986, 1991). Virtually identical results were obtained. The kinetic approach allowed integration of the biological kinetic processes of the IAWQ activated sludge model No 1 (Henze et al., 1987), to extend application of the model to situations where precipitation of minerals, stripping of gasses and biological processes take place in an environment where the pH does not remain constant. Where required the interaction between the chemical species and biological processes was included, e.g. CO₂ uptake for autotrophic nitrifier growth and NH₄⁺ uptake for heterotrophic growth and nitrification. Also, literature information on the effect of pH on the maximum specific growth rates of nitrifiers was included.
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12

Tan, Benjamin L. L. "Chemical and Biological Analyses of Selected Endocrine Disruptors in Wastewater Treatment Plants in South East Queensland, Australia." Thesis, Griffith University, 2007. http://hdl.handle.net/10072/365603.

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Studies in North America, Europe, Japan and Australia have reported the presence of endocrine disrupting compounds (EDCs) in wastewater treatment plants (WWTPs) effluent could affect physiological and reproductive function in exposed fish consistent with exposure to hormonally active chemicals. The occurrence of EDCs in rivers and receiving environments situated near WWTPs raises concern over the removal efficacy of these compounds by conventional treatment processes. The main aim of this study was to utilize chemical analyses to assess concentrations of selected endocrine disruptors as well as a biological assay to measure the potential estrogenic effects of EDCs present in water discharged from wastewater treatment plants in South East Queensland, Australia. Currently, there are few reported studies on the estrogenic effects of EDCs released from WWTPs into receiving environments in Australia. Two field sampling methods were used. Grab sampling with subsequent extraction using a solid-phase extraction (SPE) technique and passive sampling utilizing EmporeTM (styrene-divinylbenzene copolymer) disk were used in this study. A gas chromatography-mass spectrometric (GC-MS) method was successfully developed to simultaneously analyze 15 environmentally ubiquitous EDCs including phthalates, alkylphenols, tamoxifen, androgens and estrogens. Application of these methods for the determination of target EDCs in wastewater samples in this study showed 80 – 99% removal of most EDCs from influent to effluent, despite the wastewater treatment plants having different treatment processes. It was observed that the passive samplers accumulated less EDCs than predicted when compared to the grab samples. This is probably caused by, but may not be limited to, biofouling, low flow rate, biodegradation and temperature which can progressively reduce the uptake of compounds into the sampler. A future challenge would be to improve the reliability of passive samplers by reducing or controlling the environmental conditions that may impact on the passive sampler performance. Stir bar sorptive extraction (SBSE) in combination with thermal desorption coupled to GC-MS was successfully applied to analyze a range of EDCs in wastewater, biosolids and sludge. The technique was shown to be very versatile, shortening extraction time, reducing sample volume needed as well as being sensitive for the analysis of a wide range of EDCs. The results showed that there were high amounts of phthalates, alkylphenols and female hormones present in the raw influent wastewater and biosolids of the WWTP samples. For the complimentary bioassay, a proliferation assay using human breast cancer cell line MCF-7 (E-Screen assay) was used to determine estrogen equivalents (EEqs) in grab and passive samples from five municipal WWTPs. EEq concentrations derived by E-Screen assays for the grab samples were between 108 – 356 ng/L for the influents and <1 – 14.8 ng/L for the effluents with the exception of one effluent sample which was at 67.8 ng/L EEq. In most wastewater samples, the natural estrogens contributed to 60% or more of the EEq value. Based on the chemical and in vitro biological analyses results and coupled with reported no observed effect concentration (NOEC) in vivo studies (mainly based on fish vitellogenin studies), the risk of EDCs found in effluents of the monitored WWTPs having a significant impact on the receiving environment is reasonably low. Furthermore, a fugacity-based analysis was employed to model the fate of selected industrial chemicals with endocrine disrupting properties in a conventional activated sludge WWTP. Using mass balance principles, a fugacity model was developed for correlating and predicting the steady state-phase concentrations, the process stream fluxes, and the fate of four phthalates and four alkylphenols in a WWTP. The relative amounts of chemicals that are likely to be volatilized, sorbed to sludge, biotransformed, and discharged in the effluent water was assessed. Results obtained by applying the model for the eight compounds compared satisfactorily with data from the WWTP. All eight EDCs modelled in this study had high removal efficacy from the WWTP. Apart from benzyl butyl phthalate and bisphenol A, the majority is removed via biotransformation followed by a lesser proportion removed through primary sludge. Fugacity analysis provides useful insight into compound fate in a WWTP and with further calibration and validation the model should be useful for correlative and predictive purposes. In conclusion, the complementary chemical and biological analyses used in this study provided a comprehensive assessment which showed that the EDCs discharged from the monitored WWTPs would be expected to have a low impact on the receiving environments.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Faculty of Environment and Planning
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13

Nogueira, Verónica Inês Jesus Oliveira. "Assessing the effectiveness of chemical treatment with nanomaterials in improving the quality of different industrial effluents." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/15351.

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Doutoramento em Biologia
Industrial activities are the major sources of pollution in all environments. Depending on the type of industry, various levels of organic and inorganic pollutants are being continuously discharged into the environment. Although, several kinds of physical, chemical, biological or the combination of methods have been proposed and applied to minimize the impact of industrial effluents, few have proved to be totally effective in terms of removal rates of several contaminants, toxicity reduction or amelioration of physical and chemical properties. Hence, it is imperative to develop new and innovative methodologies for industrial wastewater treatment. In this context nanotechnology arises announcing the offer of new possibilities for the treatment of wastewaters mainly based on the enhanced physical and chemical proprieties of nanomaterials (NMs), which can remarkably increase their adsorption and oxidation potential. Although applications of NMs may bring benefits, their widespread use will also contribute for their introduction into the environment and concerns have been raised about the intentional use of these materials. Further, the same properties that make NMs so appealing can also be responsible for producing ecotoxicological effects. In a first stage, with the objective of selecting NMs for the treatment of organic and inorganic effluents we first assessed the potential toxicity of nanoparticles of nickel oxide (NiO) with two different sizes (100 and 10-20 nm), titanium dioxide (TiO2, < 25 nm) and iron oxide (Fe2O3, ≈ 85x425 nm). The ecotoxicological assessment was performed with a battery of assays using aquatic organisms from different trophic levels. Since TiO2 and Fe2O3 were the NMs that presented lower risks to the aquatic systems, they were selected for the second stage of this work. Thus, the two NMs pre-selected were tested for the treatment of olive mill wastewater (OMW). They were used as catalyst in photodegradation systems (TiO2/UV, Fe2O3/UV, TiO2/H2O2/UV and Fe2O3/H2O2/UV). The treatments with TiO2 or Fe2O3 combined with H2O2 were the most efficient in ameliorating some chemical properties of the effluent. Regarding the toxicity to V. fischeri the highest reduction was recorded for the H2O2/UV system, without NMs. Afterwards a sequential treatment using photocatalytic oxidation with NMs and degradation with white-rot fungi was applied to OMW. This new approach increased the reduction of chemical oxygen demand, phenolic content and ecotoxicity to V. fischeri. However, no reduction in color and aromatic compounds was achieved after 21 days of biological treatment. The photodegradation systems were also applied to treat the kraft pulp mill and mining effluents. For the organic effluent the combination NMs and H2O2 had the best performances in reduction the chemical parameters as well in terms of toxicity reduction. However, for the mine effluent the best (TiO2/UV and Fe2O3/UV) were only able to significantly remove three metals (Zn, Al and Cd). Nonetheless the treatments were able of reducing the toxicity of the effluent. As a final stage, the toxicity of solid wastes formed during wastewater treatment with NMs was assessed with Chironomus riparius larvae, a representative species of the sediment compartment. Certain solid wastes showed the potential to negatively affect C. riparius survival and growth, depending on the type of effluent treated. This work also brings new insights to the use of NMs for the treatment of industrial wastewaters. Although some potential applications have been announced, many evaluations have to be performed before the upscaling of the chemical treatments with NMs.
As atividades industriais são uma das principais fontes de poluição em todos os ambientes. Dependendo do tipo de indústria, vários tipos de contaminantes orgânicos e inorgânicos são frequentemente libertados no meio ambiente, em concentrações que podem representar riscos para os meios aquáticos. Várias metodologias, nomeadamente físicas, químicas, biológicas ou a combinação de processos, têm sido propostas e aplicadas para minimizar o impacto destes efluentes, contudo nenhuma delas foi totalmente eficaz em termos de taxas de redução dos vários contaminantes, redução da toxicidade, e melhoria de algumas propriedades físicas e químicas dos diversos tipos de águas industriais residuais. É por isso imperativo o desenvolvimento de novas metodologias de tratamento, com recurso a novos materiais que vão surgindo no mercado. Neste contexto surge a nanotecnologia, oferecendo novas possibilidades no tratamento de efluentes com base nas propriedades físicas e químicas melhoradas dos nanomateriais (NMs), que podem aumentar consideravelmente o seu potencial de adsorção e oxidação. Embora as várias aplicações dos NMs possam trazer benefícios, o seu uso também irá contribuir para a sua introdução no ambiente e varias preocupações têm vindo a ser levantadas sobre estes materiais. As mesmas propriedades que tornam os NMs tão atrativos para aplicações ambientais também podem ser responsáveis por efeitos ecotoxicológicos nas comunidades naturais. Com o objetivo de selecionar NMs para o tratamento de efluentes orgânicos e inorgânicos avaliámos a toxicidade de nanopartículas de óxido de níquel (NiO) com 100 e 10-20 nm, de dióxido de titânio (TiO2, < 25 nm) e de óxido de ferro (Fe2O3, ≈ 85x425 nm). A avaliação ecotoxicológica foi realizada através de uma bateria de ensaios com organismos aquáticos de diferentes níveis tróficos e grupos funcionais. Numa segunda etapa os dois NMs pré-selecionados foram aplicados no tratamento de efluente de lagar de azeite. Os NMs foram assim usados como catalisadores em processos de fotodegradação que incluíram os seguintes sistemas TiO2/UV, Fe2O3/UV, TiO2/H2O2/UV e Fe2O3/H2O2/UV. Utilização do TiO2 ou Fe2O3 com H2O2 revelou resultados bastante eficientes na melhoria de algumas propriedades químicas, no entanto, apesar de se ter verificado alguma redução da toxicidade para V. fischeri, a maior percentagem de redução foi registada para o sistema H2O2/UV, sem a adição de NMs. Posteriormente foi também aplicado ao mesmo efluente um tratamento sequencial utilizando oxidação catalítica com NMs e fungos. Esta nova abordagem aumentou a redução da carência química de oxigênio, do conteúdo em fenóis e da toxicidade para V. fischeri, no entanto não se verificou qualquer redução de cor e compostos aromáticos após 21 dias de tratamento biológico. Os processos de fotodegradação foram também aplicados no tratamento de efluente de pasta de papel kraft e efluente mineiro. Para o efluente orgânico a combinação NMs com H2O2 resultou em eficientes reduções quer nas propriedades químicas, quer em termos de redução da toxicidade. No entanto, para o efluente mineiro os tratamentos mais eficazes (TiO2/UV e Fe2O3/UV) apenas foram capazes de remover significativamente três metais (Zn, Al e Cd). Não obstante, estes tratamentos foram capazes de reduzir a toxicidade do efluente. Numa última etapa, avaliou-se a toxicidade dos resíduos sólidos formados após o tratamento de efluentes com NMs em larvas de Chironomus riparius, uma espécie representativa do compartimento sedimentos, em meios de água doce. Alguns desses resíduos mostraram a capacidade de afetar negativamente a sobrevivência e o crescimento de C. riparius, dependendo do efluente tratado, que os originou. Este trabalho abre novas perspetivas para a utilização de NMs no tratamento de efluentes industriais, e demonstra que apesar das aplicações anunciadas para os NMs, ainda são necessárias diversas avaliações, quer em termos da sua eficácia, quer da sua perigosidade para o ambiente antes da sua aplicação em grande escala.
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14

Howard, Samuel Clarence. "The effect of three holding tank chemicals on anaerobic wastewater treatment." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/45158.

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Sewage-holding tanks aboard recreational boats store human wastes, thereby preventing the direct discharge of wastewater to the aquatic environment. Water-conserving toilets and limited holding tank volumes produce a highly concentrated waste that must be periodically dumped to a wastewater treatment system. Prior to disposal, many boat operators add commercial preparations to control odors produced in their chemical toilets and holding tanks. The objective of this study was to determine the effects of three holding-tank chemicals on anaerobic wastewater treatment. Specifically, septic-tank performance with respect to effluent total suspended solids (TSS) and chemical oxygen demand (COD) was evaluated. Potential drain-field failure was the concern that led to the selection of TSS and COD. Drain-field failure could result from high solids carry-over or from a high concentration of COD in the effluent which would promote excessive bio-mat growth and clog the system. Laboratory septic tanks were constructed and operated for this evaluation. Methanol, paraformaldehyde and formaldehyde were each listed as an active ingredient in one of three chemical compounds used by recreational boat owners to deodorize sewage-holding tanks. septic-tank effluent TSS concentrations were not adversely effected by the shockloading with wastewater containing these chemicals. Concentrations expected to be achieved by dilution (20 and 50 percent of the recommended additive dose) resulted in septic-tank effluent COD within an acceptable range, which was determined by operation of a control system. Wastewaters containing these concentrations were not detrimental to the septic-tank treatment system. However, the full manufacturers' recommended dose of the odor control chemicals disrupted the system's ability to degrade COD. At full strength, the para formaldehyde and formaldehyde deodorants were particularly detrimental; no recovery occurred after the two-day shock-dose was completed.
Master of Science
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Hermes, Nina [Verfasser], Wolfgang [Gutachter] Imhof, and Thomas A. [Gutachter] Ternes. "Trace organic chemicals in the water cycle : Occurrence in wastewater treatment plants and removal by biological and chemical treatment / Nina Hermes ; Gutachter: Wolfgang Imhof, Thomas A. Ternes." Koblenz, 2021. http://d-nb.info/1227927800/34.

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16

Dao, Minh Trung, Thi Thanh Ngoc Tran, Thi Thao Tran Nguyen, Kim Dinh Ngo, and Vo Chau Ngan Nguyen. "Natural auxiliary coagulants - perspectives for the treatment of textile wastewater." Technische Universität Dresden, 2016. https://tud.qucosa.de/id/qucosa%3A32616.

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Applying chemical coagulants and auxiliary coagulants in wastewater treatment has become more popular in Vietnam. Although the efficacy of chemical coagulants has been well recognized, there are disadvantages associated with the use of these products, such as the inefficiency at low temperatures, increasing the residual cation in solution, causing health problems and distribution water, relatively high cost, producing high volume of sludge. Thus, it is desirable to replace these chemical coagulants for products that do not generate such drawbacks, such as natural polymers. In this paper, the authors conducted experiments by using natural auxiliary coagulants extracted from seeds of Cassia fistula (gum MHY) and chemical polymer as auxiliary coagulation to treat textile wastewater with basic polluted parameters: pH = 9.0; COD = 800 mgO2/L, color = 750 Pt-Co. The Jartest experiment results showed that the process efficiency of chemical polymer and gum MHY is not so different, with the COD removal efficiencies of 60.3% and 59.7%; the color removal efficiencies of 87.3% and 87.1%; the SS removal efficiencies of 93.2% and 92.6%. There-fore, coagulants obtained from gum MHY can be applied as the alternatives for chemical polymer in the process of treating textile wastewater.
Các ứng dụng chất keo tụ và chất trợ keo tụ hóa học trong xử lý nước thải ngày càng trở nên phổ biến tại Việt Nam. Mặc dù có nhiều ghi nhận về hiệu quả xử lý của chất keo tụ hóa học, phương pháp xử lý này vẫn tồn tại một số nhược điểm như hiệu suất xử lý thấp ở nhiệt độ thấp, nước thải sau khi xử lý còn chứa nhiều hóa chất tiếp tục làm ô nhiễm nguồn tiếp nhận, chi phí xử lý cao và tạo ra nhiều bùn thải. Do đó việc tìm kiếm một phương án xử lý thay thế, chẳng hạn sử dụng polymer tự nhiên, có thể khắc phục những nhược điểm này là rất cần thiết. Nghiên cứu này tiến hành đánh giá hiệu quả sử dụng chất trợ keo tụ sinh học ly trích từ hạt trái Muồng Hoàng yến (Cassia fistula) và chất trợ keo tụ hóa học để xử lý nước thải dệt nhuộm có các thông số ô nhiễm cơ bản: pH = 9,0; COD = 800 mgO2/L, độ màu = 750 Pt-Co. Các thí nghiệm trên bộ Jartest cho thấy hiệu quả xử lý nước thải dệt nhuộm của chất trợ keo tụ gum Muồng Hoàng yến và chất trợ keo tụ hóa học không khác biệt có ý nghĩa với hiệu suất xử lý COD lần lượt là 60,3 và 59,7%; hiệu suất xử lý độ màu là 87,3 và 87,1%; xử lý SS là 93,2 và 92,6%. Kết quả nghiên cứu cho thấy gum hạt Muồng Hoàng yến có thể sử dụng làm chất trợ keo tụ thay thế chất trợ keo tụ hóa học trong xử lý ô nhiễm nước thải dệt nhuộm.
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17

BENVENUTO, FEDERICA. "Integrated study of chemical, hydrological and biological aspects of impaired rivers to support restoration strategies." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2009. http://hdl.handle.net/10281/7504.

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The human presence and activities affect the environmental quality of water bodies in different ways. Pressures concern various aspects of the overall environmental quality and their effects are cumulative and synergic. That’s why an integrated approach is needed to understand and assess the importance of each kind of stressors and to define restoration strategies. The research work carried out in the last three years and shown in this thesis concerns impaired river ecosystems and includes, in particular: 1) Integrated study of chemical, hydrological and biological aspects of impaired rivers, especially those affected by multiple alterations in urban environments and, thus, wastewater treatment plant effluent dominated. A case study (Lura stream) is presented. 2) Development of analytical methods for determining organic micropollutants (PAHs, triazines and their main transformation products) in a wide range of surface and wastewater samples (coming from different environments in Italy and Spain) and, consequently, for evaluating the contamination from wastewater treatment plant discharges. 3) Evaluation of the organic micropollutant removal efficiencies of wastewater treatment plants and comparison of the concentrations measured in effluent samples to the environmental quality objectives fixed for surface waters, as most of the receptor flow is made by the discharged effluent itself. 4) Study of the performance of a demonstration scale constructed wetland in removing inorganic and organic contamination from wastewater treatment plant effluents, as a possible strategy for impaired river restoration.
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Alajmi, Hasan Mubarak. "Effect of physical, chemical and biological treatment on the removal of five pharmaceuticals from domestic wastewater in laboratory-scale reactors and full-scale plant." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2469.

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Pharmaceuticals and their metabolites are known to enter the environment from the effluent of wastewater treatment plants. From statistical analysis on the usage of pharmaceuticals, and their effects on the environment, five pharmaceuticals were selected for this study (Metronidazole, Trimethoprim, Sulphamethoxazole, Paracetamol and Ranitidine). Trace concentrations of pharmaceuticals were determined using a sensitive analytical method, comprising solid phase extraction (SPE) and liquid chromatography with a mass spectrometry detector (LC- MS),operating in selected ion monitoring (SIM) mode. It was found that Metronidazole, Trimethoprim, Sulphamethoxazole, Paracetamol and Ranitidine were detected at the highest levels in the wastewater entering the Sulaibiya WWTP Kuwait, with concentrations of up to 58 ng.L , 1814 ng.L , 1669 ng.L , 2086 ng.L and 2009 -1 ng.L , respectively. High removal efficiencies of these pharmaceuticals were found in the Sulaibiya WWTP. One year study was conducted to investigate the occurrence, persistence and fate of a range of these pharmaceuticals at different sampling points at the Sulaibiya WWTP. The treatment processes consisted of screening, grit removal and diffused air activated sludge treatment (primary and secondary treatment), followed by microfiltration (MF), reverse osmosis (RO), and chlorine oxidation (tertiary treatment). During primary and secondary treatment, Metronidazole, Trimethoprim, Sulphamethoxazole, Paracetamol and Ranitidine were removed efficiently with average removals efficiencies of 83.4%, 86.1%, 77.5%, 97.5% and 77.5%, respectively. The RO system lowered these pharmaceuticals further, giving overall removal efficiencies of 97%, 99%, 99%, 100% and 100% for Metronidazole, Trimethoprim, Sulphamethoxazole, Paracetamol and Ranitidine, respectively. All selected pharmaceuticals were tested in laboratory scale reactors to assess their -1 removal by chlorination and ozonation, and results showed that 10 mg.L of chlorine -1 removed these pharmaceuticals better than 15 mg.L of ozone. Lab-scale aerobic reactors (2 L), seeded with activated sludge inoculum from the Sulaibiya WWTP and fed with different concentrations of pharmaceuticals (0.1, 1 and -1 10 mg.L ), spiked individually into a synthetic wastewater showed that the TOC could be removed efficiently without inhibition by these pharmaceuticals. The fate of Metronidazole, Trimethoprim, Sulphamethoxazole, Paracetamol and Ranitidine was investigated in a membrane bioreactors (MBR), and a sequencing batch reactors (SBR), operating under strictly aerobic, and anoxic/aerobic conditions at different concentrations of a pharmaceutical mixture (PM) of the same -1 -1 -1 pharmaceuticals (1 µg.L , 1 mg.L and 10 mg.L ). The COD and TOC removal -1 efficiency decreased when the PM concentration was increased to 10 mg.L . The removal of Metronidazole and Trimethoprim was moderately effective, and similar in all the reactors. Sulphamethoxazole and Paracetamol were removed efficiently, but -1 this decreased when the PM was increased to 10 mg.L for most of the reactors, whilst Ranitidine experienced high removal rates at all concentrations in all the reactors. Analysis of the microbial diversity in laboratory reactors treating pharmaceuticals wastewater showed decreases in microbial community diversity when the PM concentration was increased. Pure cultures of bacteria isolated on selected pharmaceutical growth media were also detected in the microbial communities of reactor sludge by performing polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE).
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Jewell, Kevin [Verfasser], and Thomas [Akademischer Betreuer] [Gutachter] Ternes. "Investigations of chemically and biologically induced transformation reactions of micropollutants during biological wastewater treatment processes / Kevin Jewell ; Gutachter: Thomas Ternes ; Betreuer: Thomas Ternes." Koblenz, 2017. http://d-nb.info/1138981656/34.

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20

Wong, Yee Keung. "Feasibility of using Chlorella vulgaris for the production of algal lipids, for advancement towards a potential application in the manufacture of commodity chemicals and the treatment of wastewater." HKBU Institutional Repository, 2016. https://repository.hkbu.edu.hk/etd_oa/254.

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Driven by the increase in industrialization and population, the global demand of energy and material products is steadily growing. Microalgae have come into prominence in the past several decades due to their ability to utilize solar energy to fix atmospheric carbon dioxide, and produce biomass and lipids at productivities much higher than those possible with terrestrial biomass. The main objective of this research is to maximize the biomass and lipid production of Chlorella vulgaris by varying different external conditions so as to achieve the ideal feedstock for the production of commodity chemicals and implement wastewater treatment. The effects of various culture medium compositions on Chlorella vulgaris growth and lipid production were investigated using batch culture. Thirteen culture media: Modified Chu’s No. 10, Bold basal, BG-11, Modified BG-11, N-8, M-8, RM, Modified Spirulina, F-si, Fogg’s Nitrogen free, Fog, F/2, and Johnson medium were compared in terms of optical density, biomass production, specific growth rate and lipid production. Following a 10-day culture in a temperature controlled environment, Bold basal medium was found to have the highest average biomass productivity of 48.056 ± 2.097 mg L -1 day -1 , with overall specific growth rate of (d -1 ): 0.211 ± 0.003 and lipid productivity of 9.295 mg L -1 day -1 among the selected media. This is a basis for the optimization of different cultivating medium to enhance algal lipid production. In order to maximize the quality and quantity of the algal biomass and lipid content in Chlorella vulgaris, different strategies were used using different ratios of nitrogen and phosphorus source in the modified Bold basal medium (BBM). In the 12-day batch culture period, the highest biomass productivity obtained was 72.083 mg L -1 day -1 under Bold basal medium with Nitrogem control Phosphorus limited conditions. The highest lipid content, lipid concentration and lipid productivity obtained were 53.202%, 287.291 mg/L and 23.449 mg L -1 day -1 respectively, under Bold basal medium with Nitrogen Control Phosphorus Deprivation conditions. Nitrogen starvation was found to be the critical factor affecting the biomass production and lipid accumulation while the starvation of phosphorus induced a higher total lipid content and affected the lipid composition of Chlorella vulgaris cultures. Recently, as the demand for pure microalgae strains for the production of algal lipid as a feedstock of renewable energy has been increasing, the designation of an effective photobioreactor (PBR) for mass cultivation is essential to assure stability in the amount of feedstock. Various PBRs design such as bubbling, air-lift, porous air-lift was compared. In general, the bubbling design is a better PBR designs than the others, having the highest biomass concentration of 0.78 g/L during the culture time. Besides, it was observed that the 35 cm draft tube of the porous air-lift PBR had shorter mixing time (24.5 seconds) and higher biomass concentration (0.518 g/L) than the 50 cm air- lift design. The bubbling PBR with the highest gas flowrate of 2.7 L/min produced the highest biomass production of 0.74 g/L within the cultivation time. The information is shown to be a useful guide for determining the optimal condition of the PBRs. Light wavelengths and intensities were determinant factors in affecting the growth and lipid content of autotrophic organisms such as C. vulgaris. The experiment investigated the effect of algal lipid production by using LEDs (Light Emitting Diodes) with different wavelengths. C. vulgaris was grown in the effluent for 10 days under the photoperiod of 18:6 h Light/Dark cycles with different visible light sources (cool white, blue and red) and intensities (50 μmol m -2 s -1 ) at 25°C. The overall maximum dry biomass of 1353.33 mg/L was observed at 50 μmol m -2 s -1 cool white light during 10th culture day, with the highest overall productivity of dry biomass production (117.23 mg/L d -1 ) within cultivation time. The highest lipid content (34.06 %) was obtained with the blue color due to light efficiency and deep penetration to the photosynthetic pigments (chlorophyll) in C. vulgaris. However, the highest lipid productivity was observed in cool white light of 318.63 mg/L during the 10th culture day. The effect of light intensity toward the lipid productivity was further investigated by increasing the light intensity of cool white light. The highest lipid productivity was observed at 110 μmol m -2 s -1 in a light intensity of 658.99 mg/L during the 10th culture day. In high irradiance (110 μmol m -2 s -1 ), the proportion of poly unsaturated fatty acid (C18:1 and C18:2) contributed most of the fatty acid methyl ester (FAME) content in the collected sample, irrespective of all treatments. The next study optimized the harvesting rate of algae by using an electro- coagulation-flotation (ECF) harvester, which combines the electrochemical reaction in the electrodes and the dispersion of hydrogen gas to allow floatation of microalgae cell for surface harvesting. The response surface methodology model (RSM) was employed to optimize different ECF parameters: electrode plate material, electrode plate number, charge of electrode, electrolyte concentration and pH of the solution. The model revealed that aluminum was the best electrode material for the ECF process. It was also found that a three electrode plates setup with one anode and two cathodes had the best performance for harvesting. Additionally, sodium chloride (NaCl) at 8 g/L in harvesting medium could increase the flocculant concentration and reduce electric power consumption. Also, having the culture medium at pH 4 also had a significant effect on improving the flocculant production. Combining these optimal conditions, the highest flocculant concentration reached 2966 mg/L in 60 mins; a 79.8% increase in flocculant concentration, based on the tested conditions. The results of this study show the significance of different parameters affecting the coagulation and flocculation of C. vulgaris and provide a reference for the design of a large-scaled harvester for microalgae harvesting in the further study. To conclude, this research comprises a study on the use of indigenous algae for the production of algal lipid, which is used to produce commodity chemicals. Details on the use of nutrient sources, the techniques of cultivation and the optimization of cell harvesting were included so as to remove nutrients from effluents to minimize the occurrence of eutrophication in harbor, thereby providing economic advantages. Thus, the optimization of these processes is very adequate and offers significant advantages for the wastewater treatment. The developing of algal cell biotechnology is necessary to further enhance algal lipid production in an attempt to apply it commercially.
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21

Sigge, G. O. (Gunnar Oliver). "Integration of anaerobic biological and advanced chemical oxidation processes to facilitate biodegradation of fruit canning and winery wastewaters." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50374.

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22

Brundin, Carl. "Alternative energy concepts for Swedish wastewater treatment plants to meet demands of a sustainable society." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-146831.

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This report travels through multiple disciplines to seek innovative and sustainable energy solutions for wastewater treatment plants. The first subject is a report about increased global temperatures and an over-exploitation of natural resources that threatens ecosystems worldwide. The situation is urgent where the current trend is a 2°C increase of global temperatures already in 2040. Furthermore, the energy-land nexus becomes increasingly apparent where the world is going from a dependence on easily accessible fossil resources to renewables limited by land allocation. A direction of the required transition is suggested where all actors of the society must contribute to quickly construct a new carbon-neutral resource and energy system. Wastewater treatment is as required today as it is in the future, but it may move towards a more emphasized role where resource management and energy recovery will be increasingly important. This report is a master’s thesis in energy engineering with an ambition to provide some clues, with a focus on energy, to how wastewater treatment plants can be successfully integrated within the future society. A background check is conducted in the cross section between science, society, politics and wastewater treatment. Above this, a layer of technological insights is applied, from where accessible energy pathways can be identified and evaluated. A not so distant step for wastewater treatment plants would be to absorb surplus renewable electricity and store it in chemical storage mediums, since biogas is already commonly produced and many times also refined to vehicle fuel. Such extra steps could be excellent ways of improving the integration of wastewater treatment plants into the society. New and innovative electric grid-connected energy storage technologies are required when large synchronous electric generators are being replaced by ‘smaller’ wind turbines and solar cells which are intermittent (variable) by nature. A transition of the society requires energy storages, balancing of electric grids, waste-resource utilization, energy efficiency measures etcetera… This interdisciplinary approach aims to identify relevant energy technologies for wastewater treatment plants that could represent decisive steps towards sustainability.
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23

Butler, Erick Benjamin. "Biological Treatment of Dietary Supplementary Wastewater." Cleveland State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1264479316.

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Butler, Erick Benjamin. "Biological treatment of dietary supplement wastewater." Cleveland, Ohio : Cleveland State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1264479316.

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Thesis (M.S.)--Cleveland State University, 2009.
Abstract. Title from PDF t.p. (viewed on Feb. 16, 2010). Includes bibliographical references (p. 82-89). Available online via the OhioLINK ETD Center and also available in print.
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25

Walker, Gavin Michael. "Industrial wastewater treatment using biological activated carbon." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295433.

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26

Hou, Xiangting. "DIETARY SUPPLEMENT WASTEWATER TREATMENT BY BIOLOGICAL METHODS." Cleveland State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=csu1326295666.

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27

Decremps, Sophie. "Caractérisation du résidu particulaire et étude des mécanismes limitant la biodégradation des boues d'épuration." Thesis, Toulouse, INSA, 2014. http://www.theses.fr/2014ISAT0020/document.

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La matière des eaux usées urbaines (ERU) subit des transformations au sein des filières « eau » et « boue » des stations d’épuration (STEP). Une fraction de la matière organique est systématiquement retrouvée en fin de traitement biologique sous forme particulaire et est, à ce titre, identifiée comme non biodégradable et notée XU. L’origine « exogène » i.e. provenant de l’ERU brute, ou « endogène », i.e, résidus générés par les processus microbiens, et la contribution quantitative des composés accumulés dans cette fraction XU ne sont pas identifiables simplement. Par ailleurs, si une faible bioaccessibilité et/ou une inadéquation entre leur nature chimique et le pool enzymatique présent peuvent être suspectées, les raisons de leur caractère réfractaire sont mal connues et constituent un frein pour optimiser la valorisation de la boue par digestion anaérobie. S’intéressant spécifiquement à la fraction organique réfractaire d’une boue d’épuration, ce travail de thèse s’est donc attaché à définir son origine, à quantifier sa proportion selon différentes conditions opératoires de STEP et à caractériser ses composés d’un point de vue physique et chimique. Une approche filière a tout d’abord été menée pour analyser la relation entre l’origine et la biodégradabilité d’une boue. Deux approches de caractérisation chimique ont été mises en œuvre : (i) Analyse directe de l’empreinte chimique globale par spectrophotométrie infrarouge (IR) en réflexion totale atténuée (ATR) ; (ii) Analyses moléculaires (fluorescence 2D et 3D, UV 210 et 280 nm, dosages biochimiques) de fractions solubilisées après déconstruction thermo-chimique de l’agrégat réfractaire. Associée à des analyses statistiques, l’utilisation de l’empreinte IR s’est révélée pertinente pour différencier chimiquement différentes matrices réfractaires et suivre l’évolution des empreintes au fil des unités de traitement d’épuration. Par ailleurs, l’utilisation combinée de techniques analytiques complémentaires a permis une caractérisation plus précise des familles de molécules impliquées. Enfin, l’empreinte IR s’est avéré un outil pertinent de caractérisation de l’effet d’un traitement thermique (60 à 95°C) ou chimique (hydrolyse acide et alcaline) sur la chimie de la fraction XU
Organic matter of urban wastewaters (WW) is modified all along the treatment units of a wastewater treatment plant (WWTP). A fraction of the organic matter systematically remains at the end of biological treatment, mainly aggregated in particulate form. It is thus classified as refractory organics, noticed XU. The “exogenous” origin (e.g. originated from the urban WW) or “endogenous” one (e.g. residues produced by the microbial processes) and the quantitative contribution of compounds accumulated into the XU fraction are difficult to identify. Limited bioaccessibility and/or inappropriate chemical characteristics can be suspected. However, the reasons of their non-biodegradability are not clearly identified that limits an optimal valorization of sewage sludge by anaerobic digestion (AD). Focusing specifically on the refractory COD fraction of sewage sludge, this research work attempts to define its origin, to quantify its proportion depending on the applied operating conditions in the WWTP and to characterize the physical and chemical properties of its different compounds.A first approach is carried out to analyze the relationship between the WWTP operating conditions and the biodegradability of various sludges. The scientific approach is based on (1) the use of sludges of contrasted composition (fed with raw wastewater, or pre-settled WW, diluted primary sludge or synthetic influent, and produced with a solid retention time in the range of 2 and 70 days), and, on (2) the comparative analysis of physical, biological and chemical characteristics for refractory matrices resulting from their ultimate anaerobic digestion. Refractory COD fractionations are estimated comparing experimental and ASM1 predicted data. While 85% of anaerobic refractory organic matter remain aggregated, two characterization approaches were applied: (i) direct analysis (on unmodified particulate matter) of the global chemical fingerprint by infrared spectroscopy (IR) on attenuated total reflexion (ATR); (ii) molecular analysis (fluorescence 2D and 3D, UV 210 and 280 nm, biochemical assays) of solubilized fractions obtained by thermo-chemical solubilisation of the refractory aggregate.Combined with statistical tools (Hierarchical Ascendant Classification, HAC and Principal Component Analysis, PCA), infrared fingerprints appear relevant to chemically discriminate refractory residues of the selected sludges and hence to follow the evolution of the chemistry of matrices along the treatments chains. Main factors involved in the chemical fingerprint of XU are highlighted. For example the major effect of the chemistry of exogenic refractory compounds (XU,inf) on the XU chemical fingerprint is shown. In addition, our work underlines the interest of using complementary analytical techniques to get a more accurate chemical characterization of the molecules involved in the ultimate refractory matrices. For example, a significant contribution of proteins and humics on the chemistry of refractory aggregate could be observed with a clear contribution of bacterial compounds to protein refractory fraction.Finally, the infrared fingerprint was used to characterize the effect of heat treatments (60-95°C) or chemical treatments (acid and alkaline hydrolysis) on the chemistry of XU. In perspective, this approach could be extended to other treatments (e.g. high temperature, ozonation, enzymatic hydrolysis) to assess their effects and to define their optimal operating point for degradation of refractory compounds. Furthermore, the possibility to discriminate chemical fingerprints of different refractory residues could also be exploited. Acquiring spectral data banks could better define the scope of application of treatment units combined with the anaerobic digestion of sewage sludge
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28

Parekh, Asha 1942. "Use of magnetic nanoparticles for wastewater treatment." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82337.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Contamination of marine sediments and water environments by urban runoffs, industrial and domestic effluents and oil spills is proving to be of critical concern as they affect aquatic organisms and can quickly disperse to large distances as highlighted by the recent Gulf oil spill disaster. Polycyclic aromatic hydrocarbons (PAHs), poly chlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and heavy metals like mercury, lead and manganese are among the ubiquitous trace contaminants of marine and freshwater systems. Presence of these contaminants raise concerns as small quantities of the organic chemicals have been shown to be carcinogenic to mammals and can pose a risk to both human health and the aquatic biota. We have proposed a remediation technique based on a magnetically enhanced separation technology as an alternative to existing methods to separate the target contaminants from a sediment matrix or wastewater stream. This technology uses specifically tailored surface modified magnetic nanoparticles (MNP) that are capable of a high uptake of trace metals. These particles have a magnetic core that facilitates their recovery, a shell that provides stability, protection from oxidation and a surface to which contaminant specific ligands are attached. The advantages of this alternative are that it involves low cost chemicals and magnets, can be implemented in continuous manner and is target specific. To evaluate the feasibility of this project, we have explored thermodynamics of adsorption of contaminants on particles and transport of these particles through their medium of application (water and porous media). This work focuses on treating effluents contaminated with heavy metals, in particular, mercury. For the treatment, dithiocarbamate functionalized magnetic nanoparticles were synthesized and their adsorptive properties for mercury at different pH conditions, ionic strengths and in presence of salinity and competing ions were explored. A competitive adsorption model based on mercury speciation was developed to explain the experimental results. In addition to the adsorption experiments, theoretical models to determine binding constants of the functional group on these particles to the mercury species were evaluated using Gaussian. Transport properties through porous (representing sediment like structures) and nonporous (representing effluents) media were studied using finite element models. The simulations provided a fundamental understanding of how magnetic nanoparticles would behave differently under magnetic field gradients and in porous media. In addition, parametric results of a continuous separation model that quantifies the trend in separation as a function of system parameters were also investigated. Bench scale runs for treating wastewater-containing mercury with these particles were demonstrated. Apart from adsorption, this process uses a well-studied high gradient magnetic separation (HGMS) system to capture the magnetic nanoparticles. Breakthrough analysis of mercury and particles through the entire system, capture on particles by the HGMS system, recovering magnetic nanoparticles by stripping off the contaminant were studied in this work. As part of the PhDCEP Capstone paper, commercialization prospects of this technology have been examined for industrial applications, particularly heavy metal removal. An in-depth market analysis of North America's water and wastewater treatment chemicals market was carried out to determine market attractiveness. This was followed by competitor analysis and evaluation of this technology's value proposition based on economics and technical applicability. A roadmap of strategies that need to be adopted based on key market insights was discussed. This chapter concludes with the verdict on magnetic nanoparticles' potential as a disruptive game changer in industrial wastewater treatment market
by Asha Parekh.
Ph.D.
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29

Padron, Harold. "Combined anaerobic/aerobic treatment for municipal wastewater." ScholarWorks@UNO, 2004. http://louisdl.louislibraries.org/u?/NOD,110.

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Thesis (M.S.)--University of New Orleans, 2004.
Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Science in the Environmental Engineering Program."--Thesis t.p. Vita. Includes bibliographical references.
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30

Skonieczny, Monika. "Biological hydrogen production from industrial wastewater with «Clostridium beijerinckii»." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21981.

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An investigation of biohydrogen production from glucose by Clostridium beijerinckii was conducted in a synthetic wastewater solution. A study examining the effect of initial pH (range 5.7 to 6.5) and COD loading (range 1 to 3 g/L) on the specific conversion and hydrogen production rate has shown interaction behaviour between the two independent variables. Highest conversion of 10.3 mL H2/(g COD/L) was achieved at pH of 6.1 and COD of 3 g/L, whereas the highest production rate of 71 mL H2/(h*L) was measured at pH 6.3 and substrate loading of 2.5 g COD/L. In general, there appears to be a strong trend of increasing hydrogen production rate with an increase in both substrate concentration and pH. Butyrate (14% to 63%), formate (10% to 45%) and ethanol (16% to 40%) were the main soluble products with other volatile fatty acids and alcohols present in smaller quantities. Absence of the key nutrients biotin, MgSO4.7H2O and FeSO4.7H2O caused a significant decrease in hydrogen yield when compared to the results obtained under standard synthetic wastewater conditions, though no significant difference was observed when concentrations of biotin, MgSO4.7H2O, K2HPO4, KH2PO4, were decreased partially. Preliminary experiments with wastewater effluent obtained from a yogurt manufacturer gave poor biohydrogen production.
Ce projet de recherche porte sur la production de biohydrogène par le Clostridium beijerinckii en utilisant comem subtrat le glucose contenu dans une eau usée synthétique. Une étude de l'effet du pH initial (intervalle de 5.7 à 6.5) et de la charge organique (intervalle de DCO de 1 à 3 g/L) sur la conversion spécifique et le taux de production d'hydrogène a démontré des interactions entre ces deux variables indépendantes. La conversion la plus élevée, 10.3 mL H2/(g COD/L), a été observée à un pH de 6.1 et une DCO de 3 g/L alors que le plus haut taux de production, 71 mL H2/(h*L), a été obtenu à un pH de 6.3 et une DCO de 2.5 g/L. La tendance globale indique que le taux de production d'hydrogène augmente lorsque la charge organique et le pH augmentent. Le butyrate (14% à 63%), le formate (10% à 45%) et l'éthanol (16% à 40%) formaient les principaux produits solubles. Des acides gras volatiles et des alcools ont également été observés en faibles quantités. L'absence de nutriments essentiels tels que biotine, le MgSO4.7H2O et le FeSO4.7H2O a causé une diminution significative de la production d'hydrogène comparativement aux résultats obtenus à l'aide des conditions de référence utilisées pour la solution d'eau usée synthétique. Aucun impact significatif n'a toutefois été observé lorsque la concentration de ces nutriments était diminuée que partiellement. Des essais préliminaires à partir d'eau usée provenant d'une usine de production de yogourt ont indiqué une faible production d'hydrogène à partir de ce substrat.
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31

Reutershan, Trevor. "Chemical Kinetics and Adsorption in Wastewater Treatment Systems." Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10752236.

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The purpose of this thesis is to provide a combined theoretical and experimental approach to solve several enduring questions in wastewater chemistry. Firstly, the sulfate radical has been proposed as an alternative oxidant in advanced oxidation processes (AOPs). Its reactivity with dissolved organic matter (DOM) has not yet been studied and will be quantied in this work using electron pulse radiolysis. Next, it has been shown that DOM present in wastewater can act to impede the remediation of harmful pharmaceutical contaminants in the AOP. Using a new binding model presented here, this association was quantied in terms of equilibrium constants. Lastly, due to the use of bleach to prevent biofouling of the membrane bioreactor in wastewater treatment facilities, chlorine atom chemistry is becoming increasingly important to study regarding AOPs. A numerical system is provided in this thesis to understand the reactivity of chlorine atoms in the presence of wastewater constituents.

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32

Chai, Qian. "Modeling, estimation, and control of biological wastewater treatment plants." Doctoral thesis, Norwegian University of Science and Technology, Department of Engineering Cybernetics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2082.

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The activated sludge process (ASP), as the most generally applied biological wastewater purification technique, attracts a great deal of attention from the research community in a highly populated, industrialized world. The main objective of this thesis is to investigate methods for e¢ cient development of activated sludge plant models and for possible improvements in process operation and performance through applications of advanced modeling and control techniques. Different topics in advanced control such as parameter estimation, state estimation, and model predictive control, are addressed, and the methods investigated in this thesis are illustrated with two activated sludge processes, a laboratory-scale nitrogen (N) removal plant and a full-scale phosphorus (P) removal plant: the Duvbacken wastewater treatment plant (WWTP).

As model representation is important in control oriented modeling, the object-oriented modeling approach providing open component-based architectures and reuse of components, is suggested in this thesis to achieve a more flexible model representation. The models of the N-removal process and the Duvbacken WWTP are developed based on the Activated Sludge Models (ASMs) which are generally accepted as the standard models of activated sludge processes (ASPs). The dynamic models are implemented in the object-oriented modeling language Modelica using the Dymola simulation environment, based on a modification of the Modelica library WasteWater. In order to build a good software development environment, special consideration is given to two Dymola interfaces: the Dymola-Matlab interface provided by Dymola and the Dymola-Python interface developed by the author. The application of the modeling approach in this thesis shows that the combination of Modelica/Dymola for efficient object-oriented modeling and Matlab for further analysis is a powerful tool for control system design.

The performances of some widely used state estimation techniques, such as the standard Kalman filter (KF), the extended Kalman filter (EKF), the unscented Kalman filter (UKF), the square-root unscented Kalman filter (SRUKF), and the moving horizon estimation (MHE), are evaluated with application to the N-removal process. The comparison of these filters for the N-removal process shows that the SRUKF improves numerical properties of the UKF and provides the best estimation performance, and the discrete-time EKF gives the fastest performance with a satisfactory estimation result. In addition, since a good characterization of the main compositions in the influent is very important to the performance of the ASM models, a method for simultaneously estimating both model state and influent composition (model disturbance) is developed using the discrete-time EKF and illustrated with the Duvbacken WWTP. The filter has a good convergence property for the observable process based on responses from the simulation model. However, when the filter is evaluated based on the experimental data, the performance of the filter is relatively poor due to unobservability of the system. Additional measurements are therefore needed to render the Duvbacken system locally observable.

Parameter estimation of activated sludge plant models is a challenging task, since the models are in general large-scale, nonlinear, and overparameterized. A procedure for parameter identifiability analysis is discussed and tested with the Duvbacken model. This systematic method proves to be very useful, since it reduces a large number of parameters to a small subset of parameters that can be identified from the available experimental data. The fitting of the model to real data from the industrial plant is not great but satisfactory, especially for those outputs which are important to the plant operation (e.g. concentration of phosphate SPO4 and concentration of total phosphorus TP).

Advanced control strategies for the ASP aeration system are suggested with the focus on the MPC algorithm, since MPC provides an optimization-based procedure with an elegant way of handling constraints and with capabilities of removing process disturbances. Both linear and nonlinear MPC techniques are evaluated with the N-removal process, and the simulation results show that the performances of the MPC controllers are satisfactory: the controllers guarantee that the strict e­ uent requirements are fulfilled. The nonlinear MPC strategy is also compared with some conventional rule-based controllers, and the MPC controller shows the most reduction of the energy consumption and offers the easiest way to handle the inequality constraints.

Finally, recommendations for future research directions are suggested to an N-removal project group at Telemark University College, Norway.


Paper B reproduced with kind permission of Elsevier
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33

Aboobakar, Amina. "Quantification of greenhouse gas emissions in biological wastewater treatment." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/8494.

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There is an increasing need to reduce greenhouse gas (GHG) emissions and to identify influencing factors from wastewater treatment plants (WWTPs), particularly process emissions consisting of nitrous oxide (N2O), and methane (CH4) GHG, with global warming potentials about 310 and 21 times higher than carbon dioxide (CO2) respectively (IPCC, 2006). However, the challenges offered by full-scale environments, have to date, restricted a real-time, comprehensive approach of monitoring emissions and influencing factors. This study aimed at addressing this knowledge gap, by reporting the findings of a long-term, online, continuous monitoring of GHG emissions and operational variables. Lanes were monitored in nitrifying activated sludge plants (ASP) controlled under ammonia (NH4 + ) and dissolved oxygen (DO) set-points (DO setpoints monitored: 1.5 and 2.0 mg/L), as well as in a biological nutrient removal plant (BNR) under NH4 + control. The findings showed that CH4, although potentially formed in non-aerated compartments, was emitted in aerobic zones, at an average emission factor (EF) of 0.07 % of influent and removed chemical oxygen demand (COD). Nitrous oxide EFs on the other hand, depended on relative nitrogen fractions, with influent-based EFs showing a best-case scenario, at 0.05–0.72 % of both influent total nitrogen (TN) and NH4 + , compared to the higher EFs based on removed nitrogen at 0.13–3.9 % of TN and NH4 + removed. The processes operated under the same control settings (DO set-point 1.5 mg/L), had similar, or identical, EF, suggesting that settings could help predict the range of EF. Nitrous oxide was always produced in the presence of NH4 + , even at low concentrations (=<0.5 mg/L), therefore linking N2O production with NH4 + oxidation, particularly with nitrifier nitrification. Incomplete denitrification under low carbon to nitrogen (C/N) ratios also triggered N2O production (EFs of 2.4 and 4.1 % of reduced TN at C/N ratios of 2.8 and 2.4 respectively), particularly with intermittent aeration. Therefore, nitrifier denitrification and incomplete denitrification simultaneously occurred and triggered N2O production in the final stages of nitrification. The BNR lane was the most operationally stable process, therefore offering the best balance between efficiency (60–99 % less aeration and energy per kg of treated NH4 + ), low carbon footprint and reduced EFs (0.08–0.1 % of all nitrogen fractions). The second best option was the DO set-point control of 1.5 mg/L, with low EFs (0.05–0.2 %), stable operational conditions and reduction in aeration requirements (up to 340 % less than DO set-point 2.0 mg/L). Operating ASP under NH4 + control however, led to 7–96 % more efficiency than under DO set-points, although it required better control in the back end of the process. Only an online, long-term methodology such as adopted in this study, could provide insights into emission variability and the effect of operational variables on promoting or reducing emissions. Based on this, strategies to mitigate emissions at full-scale were recommended.
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34

Coughtrie, Andrew Robert. "Coupling hydrodynamic and biological process models for wastewater treatment." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/16207/.

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This thesis considers the problem of modelling bioreactors with complex mixing and biokinetic growth based on both soluble nutrients and photosynthesis. From the results of investigations performed on the different modelling methods for nutrient and photosynthesis dependent biomass growth a method of coupling the two biokinetic models was proposed. This new photosynthesis-nutrient (PN) model was then investigated, validated and determined capable of predicting growth characteristics dependent on both nutrient and photosynthetic processes. Additionally an investigation into the factors which may influence the results when using computational fluid dynamics (CFD) to model the flow field within a gas-lift bioreactor was performed. It was determined that one of the main factors which must be considered when modelling bioreactors with boundary layer flow separation is the choice of turbulence model. In the case presented here it was found that the transition SST turbulence model provided the best results with the k-w SST also performing well. Finally, a method of coupling the PN and CFD models was proposed and investigated. The photosynthesis-nutrient-hydrodynamic (PNH) model also incorporated a model for diffusion of light within the bioreactor to allow for investigations into the effects of light absorption and scattering within the bioreactor and how mixing affects the active biomass. Further investigation of this new PNH model determined that the coupling of the biokinetics and flow field provided some insight into the ability of a well-mixed bioreactor to counter low light penetration to an extent.
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35

Zivich, Jamie Dionne. "Biological Health Assessment of an Industrial Wastewater Treatment Facility." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/43523.

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The biological treatment of wastewaters from an industry was studied. Among the more important wastewater constituents of concern were high levels of suspended solids, due to graphite and nitrocellulose, the solvents, ethanol and acetone, and nitroglycerine (NG). The goal of this project was divided into four objectives. The impacts of graphite on a microbial population were evaluated. Sequencing batch reactors (SBRs) were used to monitor the effects of graphite on mixed liquor suspended solids (MLSS), removal of soluble chemical oxygen demand (sCOD), and specific oxygen uptake rates (sOUR). Graphite appeared to have no adverse effect on the microbes. The potential benefits of adding sucrose, nitrogen, and phosphorus to SBRs were evaluated. The MLSS was maintained at 1,250 mg/L, similar to the microbial population in the suspended growth system at the industry. Sucrose addition increased the sCOD removals and sOUR. No direct effect was observed with the addition of nitrogen and phosphorus. The treatability of acetone and ethanol was studied through sOUR and batch testing to determine bacterial response to solvents. Both solvents were utilized by the microbes. The concentrations tested proved to be beneficial, not inhibitory. Ethanol and a 50/50 mixture of acetone and ethanol were more viable substrates than acetone. NG treatability was examined under anoxic and aerobic conditions in SBRs and batch biological reactors. NG degradation occurred under anoxic conditions, but was more favorable in aerobic environments. NG was degraded in all SBR tests to below detection limit (0.5 mg/L); therefore, the optimal treatment could not be determined.
Master of Science
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36

Bi, Tianzhu. "Biological Treatment of Milk and Soybean Wastewater with Bioproducts." Cleveland State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=csu1292017443.

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37

Kang, Young Woon. "Biological treatment of turkey processing wastewater with sand filtration." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1078903968.

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Thesis (Ph. D.)--Ohio State University, 2003.
Title from first page of PDF file. Document formatted into pages; contains xxi, 187 p.; also includes graphic (some col.). Includes abstract and vita. Advisor: Karen M. Mancl, Dept. of Food, Agricultural, and Biological Engineering. Includes bibliographical references (p. 169-178).
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38

Cerqueira, Alexandre Andrade. "Aplicação da técnica de eletrofloculação utilizando corrente alternada de frequência variável no tratamento de água de produção da indústria do petróleo." Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2426.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro
O principal objetivo da tese está relacionado ao tratamento de águas oleosas através da eletrofloculação utilizando corrente alternada de frequência variável, o qual procurou explorar as potencialidades desta técnica. Com a crescente demanda por petróleo e seus derivados, é cada vez maior a produção dessas águas residuárias que, antes de serem descartadas, precisam ser submetidas a tratamento que satisfaçam aos requisitos legais. O trabalho apresentado descreve o levantamento bibliográfico e os resultados dos ensaios realizados, empregando o tratamento de eletrofloculação com a finalidade de remover as substâncias consideradas poluentes presentes nestes efluentes. O processo de eletrofloculação foi testado tanto para o tratamento em corrente continua quanto em corrente alternada de frequência variável em efluentes sintéticos e reais de alta salinidade, contendo teores elevados de óleos e graxas, turbidez e cor. Eficiências de redução de 99% para óleos e graxas, cor e turbidez foram obtidos utilizando eletrodos de alumínio. O processo de eletrofloculação demonstrou-se bastante vantajoso em função da alta condutividade que permite o tratamento com menor consumo energético. A tecnologia de eletrofloculação com corrente alternada quando comparada com a tecnologia de corrente contínua se mostrou muito eficiente em relação a economia no desgaste de massa de eletrodos, o que, dependendo do tempo de aplicação da corrente elétrica nas mesmas condições de estudo, houve redução de mais da metade do consumo.
The main aim of the present work was to study the treatment of oil wastewaters using electroflocculation with AC and variable frequency and to explore the potentiality of the process. With the increasing demand for oil and its derivatives the production of oil wastewaters also increases. Before its final disposal, these undesirable wastewaters must undergo treatment to adjust its quality to legal requirements. The present work presents an extensive literature survey and the experimental results obtained can be deemed as excelent, as reduction efficiencies of about 99% of the main quality parameters, namely, oils and greases, turbidity and colour, were obtained. The process was carried out using both direct and variable frequency alternate currents in high salinity samples of both real and synthetic wastewater. containing high levels of oil and grease, turbidity and color. Reduction efficiencies of 99% for oils and greases, color and turbidity were obtained using aluminum electrodes. The process electroflocculation seem to be quite advantageous due to the the fact that high conductivity values result in considerably low energy consumption. Electroflocculation processes using AC , as compared with similar processes, proved to very efficient, mainly because of its potential economy in mass of electrodes, which, depending on the time of application of electric current in the same conditions of study, a reduction of more half the consumption was obtained.
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39

Manchisi, James. "Development of sustainable adsorbents for wastewater treatment." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6448/.

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The purpose of this study was to develop adsorbents from slag materials as a low cost method to purify acid mine drainage of high acidity and toxic metal ions content. The study included adsorbent characterisation and adsorption experiments to understand the adsorption behaviour of a multi-adsorbate system of Cd\(^2\)\(^+\), Co\(^2\)\(^+\), Cu\(^2\)\(^+\), Fe\(^2\)\(^+\) and Mn\(^2\)\(^+\) ions. It was found that the adsorbents had low surface area and unfavourable pore size distribution. The chemical activation of the adsorbents improved the adsorbent properties, and thus increased amounts of metal ions adsorbed. However, the adsorption of multiple metal ions was only effective in dilute solutions, with adsorption efficiency increasing with increase in phase ratio, pH and temperature. The adsorption data was best described by pseudo second order kinetic and double exponential diffusion models. The mechanisms involved adsorption, precipitation and ion exchange. The adsorbent capacities were relatively low, with selectivity proposed as Fe\(^2\)\(^+\)>Cu\(^2\)\(^+\)> Cd\(^2\)\(^+\)>Co\(^2\)\(^+\)>Mn\(^2\)\(^+\). The fixed bed efficiencies were satisfactory but the adsorbents were easily exhausted, which indicated a limited ability for the adsorbent materials to be regenerated. However, desorption of metal ions was favourable, and this may provide an opportunity for metal ions to be recovered and for spent adsorbents to be disposed safely.
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40

Berktay, Ali. "The effects of pressure on aerobic biological wastewater treatment using rotating biological contractors." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/11709.

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The aim of this research was to investigate the application and effects of pressure on an aerobic biological wastewater treatment process. For the purpose of the investigation two specially designed, identical, laboratory-scale rotating biological contactor (RBC) units were constructed. One of these was held in a steel pressure vessel while the reference unit was operated open to the atmosphere. The treatment capabilities of the pressurized unit, as compared to those of the reference unit, were determined for a variety of organic loadings at increasing pressures up to a limit of 6 bar. During the investigation, the substrate employed was a synthetic wastewater made up frequently in the laboratory. Most of the analytical work was carried out on composite druly samples of the feed wastewater and of the two effluents produced, both filtered and nonfiltered. In addition, sludge samples from both units were regularly tested for a variety of sludge parameters. The water quality parameters investigated were the 5-day Biochemical Oxygen Demand (BOD5), the Chemical Oxygen Demand (COD), Suspended Solids, pH, Temperature, Ammoniacal Nitrogen and Total Oxidized Nitrogen (TON). The yield of sludge produced and certain characteristics of sludge i.e. Specific Stirred Volume Index (SSVl). Specific Resistance to Filtration, were also obtained. The quantity of air required for the pressurized treatment unit was also investigated. The pressurized treatment unit has demonstrated the capability of operating with a high level of carbonaceous oxidation and nitrification at organic loadings of up to 13 g BOD5/ m2 of disc area per day. In comparison with the identical reference unit operated at atmospheric pressure, the pressurized unit demonstrated slightly improved BODs and COD removal efficiencies, a greatly improved level of nitrification and a substantially lower sludge production. All these characteristics improved with increasing pressure.Of particular importance the sludge yield coefficient was always significantly lower for the pressurized unit than for the reference unit and results such as 0.12 kg dry solids/ kg BOD5 removed at 6 bar pressure are highly signif1cant with regard to the requirements of the modern wastewater treatment industry. Additional investigations were carried out to determine the cost of a proposed full-scale pressurized treatment unit with a design based upon the findings of this investigation. These were compared with the costs of a conventional biological treatment process capable of treating an equivalent wastewater loading. The comparison between the pressurized unit and the selected processes were made for three populations (500, 1,000 and 3,000 persons). The sludge disposal costs of the pressurized unit were appreciably lower than those for the other processes. The results indicated that the cost of the pressurized unit (present value for a twenty-year period) and the costs of activated sludge and conventional RBC processes were found to be similar for the smaller populations. However a substantial saving could be obtained with the pressurized unit for the larger populations. In addition there is an indication that the land requirement of the pressurized treatment unit decreases appreciably as the flow rate increases.
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41

Liu, Hong, and 劉紅. "Bio-hydrogen production from carbohydrate-containing wastewater." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31244518.

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42

McHarg, Amy Marie. "Optimisation of municipal wastewater biological nutrient removal using computer simulation." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/10479.

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Due to more stringent regulations for secondary municipal wastewater treatment, municipalities are beginning to implement tertiary treatment in their wastewater treatment plants. Tertiary treatment would be the removal of either phosphorous or nitrogen or both from the wastewater before it is discarded from the plant. Biological treatment is becoming an increasingly popular process used to accomplish this extra removal. There are several processes available that will provide acceptable levels of biological nutrient and BOD removal from wastewater. Three well-known processes were considered in this study - the Modified Bardenpho Process, the Modified UCT Process and the A2/O Process. For each of these processes, 2 1evel fractional factorial designs along with least squares analysis were performed in order to determine the optimal operating variables (recycle rates and anaerobic, anoxic and aerobic zone retention times), with respect to the final nitrogen concentration, the final phosphorous concentration and a combination of the final nitrogen and phosphorous concentrations. The analyses were performed at 10°C and 20°C with low, medium and high primary effluent concentrations. Due to the complexity of the processes, lab scale experiments were not feasible. Therefore, a widely accepted calibrated biokinetic model (Activated Sludge Model No 2d) was used in a computer simulation program (GPS-X) to gather the necessary data for analysis. Actual plant data were used to test the validity of the simulation model with respect to organic and nitrogen removal. Using the published kinetic and stoichiometric parameters for both temperature levels, the Activated Sludge Model provided a good estimation of outlet concentration levels. It was found that all three biological nutrient removal (BNR) process were capable of achieving an effluent soluble phosphorous concentration below the required limit of 1 mgP/L at 10 and 20°C with low, medium and high primary effluent concentration when the effluent nitrogen concentration was neglected. Neither the Modified Bardenpho, the Modified UCT nor the A 2/O process were capable of producing an effluent with nitrogen concentrations below the required limit of 5 mgN/L at high primary effluent concentrations. The Modified Bardenpho and the Modified UCT processes were both successful in achieving a combined nitrogen and phosphorous removal below their regulatory limits for low primary effluent concentrations at 10 and 20°C. The Modified Bardenpho process, at 20°C with medium primary effluent concentrations, was found to achieve an effluent with nitrogen and phosphorous concentrations below 5 mgN/L and 1 mgP/L, respectively. After analyzing the effects of individual operating variables, it was found that the anoxic recycle for the Modified UCT process had an insignificant effect on total nitrogen (TN) and soluble phosphorous (sP) removals and did not need to be included in future experimental studies. All of the input variables to the MB and A2/O process proved to be somewhat significant and it is recommended that they be kept within future experimental designs. From this study it was found that both the MB and MUCT process are capable of achieving the TN, sP and cBOD5 removals that ROPEC requires. However only the MB process proved to be a robust system when subjected to storm conditions (i.e., peaks in influent flow rate) with respect to sP and cBOD5 removal. Neither the MB nor the MUCT process provided acceptable TN removals when subjected to storm conditions. It is recommended that ROPEC further evaluate the MB process as a possible means to achieve simultaneous cBOD5, TN and sP removal.
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43

Li, Wen. "Improvement of Biological Processes of Inland Municipal Wastewater Treatment Plant." Thesis, KTH, Mark- och vattenteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190742.

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This master thesis gives an account for various aeration schemes that are utilized in conventional activated sludge treatment process in a wastewater treatment plant. By altering between different aeration schemes, the project aimed at reducing energy consumption along with maintaining the treatment performance at the plant. A series of experiments on the treatment performance over several different aeration schemes thus has been conducted on site at Solviken in Mora, Sweden. The project is basically a case study where no parameters were manually controlled except for the aeration schemes at the plant. Energy consumption reduction is logically relative to the ratio between aeration and non-aeration intervals. Several criteria were tested in regards to the treatment performance, including pH value, organic matters, phosphorus substances and microorganisms. The study has come up with a superior aeration scheme for the plant, as well as indicated processes that can be improved at the plant.
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44

Gaslightwala, Abizer F. (Abizer Firoze) 1973. "Evaluation wastewater treatment technologies at Ford Powertrain." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/9001.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, 2000.
Includes bibliographical references (p. 80).
In preparation for an upcoming EPA proposal regarding Free Oil & Grease (FOG) and metal ion content in wastewater effluent, a study was performed for Ford Motor Company that assesses various seconctary wastewater treatment technologies. The three water purification technologies, membrane filtration, biological treatment, and clay media adsorption, were evaluated as secondary water treatment solutions for oily wastewater. Three different types of membrane technologies were tested: polymeric, ceramic, and sintered stainless steel. In regards to FOG, the membrane technologies and the clay media were able to reduce FOG levels below the EPA proposal of 17 mg/L. However, the clay media did not show a strong affinity for metal ions. The membrane technologies were 'lble to reduce all iron levels below the recommended limits (1.3 mg/L). However, they were not able to reduce aluminum below the proposed limit (I mg/L). This implies that additional downstream processing would be required to remove the aluminum if the membrane solution was implemented and the regulation passes as proposed. The biological wastewater treatment was not tested during these trials, but was assumed to be able to meet all FOG and metal requirements proposed by the EPA. Based on these experimental results and basic design assumptions, an economic analysis over a ten-year period indicated that the biological waste treatment system was the lowest in costs, followed by the polymeric membranes. The estimated installed and operating costs for both technologies was $800,000 and $1,200,000 respectively. The nearest alternative solution, the stainless steel membranes, was over 200% more expensive than the lowest cost option. Based on this economic analysis, Ford should pursue additional research and experiments into the feasibility of using biological wastewater treatment to meet EPA proposed regulations. More specifically, experiments should be conducted to help verify the assumptions used and economic results obtained in this study. As a secondary option, in the absence of additional data, polymeric membranes are recommended as the best solution, despite additional processing needed to remove aluminum ions from water effluent. In addition, the biological waste treatment option has the potential to reduce chemical oxygen demand (COD) measurements below the levels seen by any of the membrane technologies. None of the membrane technologies investigated were capable of reducing COD levels below 200 mg/L on a consistent basis, thus indicating that this might be a fixed barrier for these technologies. Although not relevant today, COD measurements might have significant importance in future EPA water regulations, and should be taken into account when recommending a treatment solution.
by Abizer F. Gaslightwala.
S.M.
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45

Mendoza, Espinosa Leopoldo Guillermo. "Upflow and downflow biological aerated filters (BAFs) for wastewater treatment." Thesis, Cranfield University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268131.

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46

Uttley, P. J. "Integration of biological wastewater treatment and algal growth for biofuels." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6393/.

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This thesis is concerned with the production of biofuels from microalgae that can be grown in wastewater on marginal land. Algal-derived biodiesel is a promising alternative to both the finite reserves of fossil fuels and also the current biofuel crops that take up agricultural land. The case for coupling biological wastewater treatment to the production of algal biodiesel is a compelling one that is explored in this research using a combination of mathematical modelling and laboratory experiments. Algae utilise by-products of the wastewater treatment process such as carbon dioxide, nitrate and ammonia. In this work, a mathematical model of an integrated wastewater treatment and algal cultivation system is presented. The model contains two units: an activated sludge unit for secondary wastewater treatment and a pond for the cultivation of algae. These units have both liquid phase and gas phase integration. For the liquid phase, the treated effluent from the activated sludge unit is transferred to the algal pond to provide nutrients for algal growth. The model also incorporates gas-phase integration whereby the CO2 rich off-gas from the activated sludge unit is captured and used to enhance the algal growth. In addition, the O2 enriched off-gas from the algal pond is recycled back to improve dissolved oxygen levels in the activated sludge unit. The mathematical model uses equations for algal growth that were developed using laboratory experiments to measure the effect of dissolved CO2, nitrate and ammonia on the growth kinetics of a typical strain of freshwater alga: Chlorella sp. The model includes the industry standard Activated Sludge Model No. 3 for wastewater treatment. An economic profit function is used in the model to find the optimal pattern of gas phase integration to maximise Net Present Value over a specified project lifetime. For the case considered, the model predicts that integration using the gas and liquid exchange described above is necessary for a profitable outcome. This is a general approach that can be used to retrofit biofuel production onto an existing wastewater site, or design a new integrated system from first principles.
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Yan, Qingmei. "Biological nitrogen removal of saline wastewater by ammonium oxidizers." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42182116.

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48

Lumbers, Jeremy. "Rotating biological contactors : mechanisms, modelling and design." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47161.

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49

Hodges, Alan J. "Alternative Treatment Technologies for Low-Cost Industrial and Municipal Wastewater Management." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5884.

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Roughly the same volume of water that rushes over the Niagara Falls is produced as wastewater in North America. This wastewater is treated through a variety of means to ensure that it can be safely returned to the natural ecosystem. This thesis examines two novel means for this treatment, one biological and one physical-chemical in nature, namely, Rotating Algae Biofilm Reactor treatment and expanded shale augmented coagulation-flocculation. Rotating algae biofilm reactors (RABRs) support biofilm algae growth, and in turn, the algae take up harmful contaminants from the wastewater. This system was tested in wastewater from petroleum refining operations. The efficacy of the RABR system was compared with a traditional method of wastewater treatment, open pond lagoons, where wastewater is open to sunlight and algae growth occurs in suspension as compared to the biofilm formed by the RABR system. The RABR treatment demonstrated a statistically significant increase in removal of three constituents in wastewater that are harmful to the environment: nitrogen, phosphorus, and suspended solids. Additionally, the RABR treatment demonstrated increased biomass production. This biomass can be converted into a variety of bioproducts including biofuels, agricultural feed, and nutraceuticals. This study is the first demonstration of this system in petroleum refining wastewater. Currently, many wastewater treatment facilities use coagulation-flocculation to remove suspended solids from the wastewater. To achieve this removal, coagulants are added to the wastewater, which removes surface charges of the suspended particles, allowing particles in solution to coalesce and settle by gravity out of solution. One common coagulant added to wastewater is ferric sulfate. This study demonstrated that the addition of a new compound, expanded shale, to ferric sulfate could greatly improve the efficacy of the existing ferric sulfate coagulation system.
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Kent, Tanya Denise. "The effect of media size on biological aerated filter performance." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287176.

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