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1
Holt, Peter Kevin. "ELECTROCOAGULATION: UNRAVELLING AND SYNTHESISING THE MECHANISMS BEHIND A WATER TREATMENT PROCESS." Thesis, The University of Sydney, 2002. http://hdl.handle.net/2123/624.
Full textAbstract:
Electrocoagulation is an empirical (and largely heuristic) water treatment technology that has had many different applications over the last century. It has proven its viability by removing a wide range of pollutants. The approach to reactor design has been haphazard, however, with little or no reference to previous designs or underlying principles. This thesis reviewed these reactor designs, identifying key commonalities and synthesising a new design hierarchy, summarised by three main decisions: 1. Batch or continuous operation; 2. Coagulation only or coagulation plus flotation reactors, and; 3. Associated separation process if required. This design decision hierarchy thereby provides a consistent basis for future electrocoagulation reactor designs. Electrochemistry, coagulation, and flotation are identified as the key foundation sciences for electrocoagulation, and the relevant mechanisms (and their interactions) are extracted and applied in an electrocoagulation context. This innovative approach was applied to a 7 L batch electrocoagulation reactor treating clay-polluted water. Structured macroscopic experiments identified current (density), time, and mixing as the key operating parameters for electrocoagulation. A dynamic mass balance was conducted over the batch reactor, for the first time, thereby enabling the extraction of a concentration profile. For this batch system, three operating stages were then identifiable: lag, reactive, and stable stages. Each stage was systematically investigated (in contrast to the previous ad hoc approach) with reference to each of the foundation sciences and the key parameters of current and time. Electrochemical behaviour characterised both coagulant and bubble generation. Polarisation experiments were used to determine the rate-limiting step at each electrode's surface. Consequently the appropriate Tafel parameters were extracted and hence the cell potential. At low currents both electrodes (anode and cathode) operated in the charge-transfer region. As the current increased, the mechanism shifted towards the diffusion-limited region, which increased the required potential. Polarisation experiments also define the operating potential at each electrode thereby enabling aluminium's dissolution behaviour to be thermodynamically characterised on potential-pH (Pourbaix) diagrams. Active and passive regions were defined and hence the aluminium's behaviour in an aqueous environment can now be predicted for electrocoagulation. Novel and detailed solution chemistry modelling of the metastable and stable aluminium species revealed the importance of oligomer formation and their rates in electrocoagulation. In particular, formation of the positively trimeric aluminium species increased solution pH (to pH 10.6), beyond the experimentally observed operable pH of 9. Thereby signifying the importance of the formation kinetics to the trimer as the active coagulant specie in electrocoagulation. Further leading insights to the changing coagulation mechanism in electrocoagulation were possible by comparison and contrast with the conventional coagulation method of alum dosing. Initially in the lag stage, little aggregation is observed until the coagulant concentration reaches a critical level. Simultaneously, the measured zeta potential increases with coagulant addition and the isoelectric point is attained in the reactive stage. Here a sorption coagulation mechanism is postulated; probably charge neutralisation, that quickly aggregates pollutant particles forming open structured aggregates as indicated by the low fractal dimension. As time progresses, pollutant concentration decreases and aluminium addition continues hence aluminium hydroxide/oxide precipitates. The bubbles gently sweep the precipitate through the solution, resulting in coagulation by an enmeshment mechanism (sweep coagulation). Consequently compact aggregates are formed, indicating by the high fractal dimension. Flotation is an inherent aspect of the batch electrocoagulation reactor via the production of electrolytic gases. In the reactor, pollutant separation occurs in situ, either by flotation or settling. From the concentration profiles extracted, original kinetic expressions were formulated to quantify these competing removal processes. As current increases, both settling and flotation rate constants increased due to the additional coagulant generation. This faster removal was offset by a decrease in the coagulant efficiency. Consequently a trade-off exists between removal time and coagulant efficiency that can be evaluated economically. A conceptual framework of electrocoagulation is developed from the synthesis of the systematic study to enable a priori prediction. This framework creates predictability for electrocoagulation, which is innovative and original for the technology. Predictability provides insights to knowledge transfer (between batch and continuous), efficient coagulant and separation path, to name just a few examples. This predictability demystifies electrocoagulation by providing a powerful design tool for the future development of scaleable, industrial electrocoagulation water treatment design and operation process.
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Holt, Peter Kevin. "ELECTROCOAGULATION: UNRAVELLING AND SYNTHESISING THE MECHANISMS BEHIND A WATER TREATMENT PROCESS." University of Sydney. Chemical Engineering, 2003. http://hdl.handle.net/2123/624.
Full textAbstract:
Electrocoagulation is an empirical (and largely heuristic) water treatment technology that has had many different applications over the last century. It has proven its viability by removing a wide range of pollutants. The approach to reactor design has been haphazard, however, with little or no reference to previous designs or underlying principles. This thesis reviewed these reactor designs, identifying key commonalities and synthesising a new design hierarchy, summarised by three main decisions: 1. Batch or continuous operation; 2. Coagulation only or coagulation plus flotation reactors, and; 3. Associated separation process if required. This design decision hierarchy thereby provides a consistent basis for future electrocoagulation reactor designs. Electrochemistry, coagulation, and flotation are identified as the key foundation sciences for electrocoagulation, and the relevant mechanisms (and their interactions) are extracted and applied in an electrocoagulation context. This innovative approach was applied to a 7 L batch electrocoagulation reactor treating clay-polluted water. Structured macroscopic experiments identified current (density), time, and mixing as the key operating parameters for electrocoagulation. A dynamic mass balance was conducted over the batch reactor, for the first time, thereby enabling the extraction of a concentration profile. For this batch system, three operating stages were then identifiable: lag, reactive, and stable stages. Each stage was systematically investigated (in contrast to the previous ad hoc approach) with reference to each of the foundation sciences and the key parameters of current and time. Electrochemical behaviour characterised both coagulant and bubble generation. Polarisation experiments were used to determine the rate-limiting step at each electrode�s surface. Consequently the appropriate Tafel parameters were extracted and hence the cell potential. At low currents both electrodes (anode and cathode) operated in the charge-transfer region. As the current increased, the mechanism shifted towards the diffusion-limited region, which increased the required potential. Polarisation experiments also define the operating potential at each electrode thereby enabling aluminium�s dissolution behaviour to be thermodynamically characterised on potential-pH (Pourbaix) diagrams. Active and passive regions were defined and hence the aluminium�s behaviour in an aqueous environment can now be predicted for electrocoagulation. Novel and detailed solution chemistry modelling of the metastable and stable aluminium species revealed the importance of oligomer formation and their rates in electrocoagulation. In particular, formation of the positively trimeric aluminium species increased solution pH (to pH 10.6), beyond the experimentally observed operable pH of 9. Thereby signifying the importance of the formation kinetics to the trimer as the active coagulant specie in electrocoagulation. Further leading insights to the changing coagulation mechanism in electrocoagulation were possible by comparison and contrast with the conventional coagulation method of alum dosing. Initially in the lag stage, little aggregation is observed until the coagulant concentration reaches a critical level. Simultaneously, the measured zeta potential increases with coagulant addition and the isoelectric point is attained in the reactive stage. Here a sorption coagulation mechanism is postulated; probably charge neutralisation, that quickly aggregates pollutant particles forming open structured aggregates as indicated by the low fractal dimension. As time progresses, pollutant concentration decreases and aluminium addition continues hence aluminium hydroxide/oxide precipitates. The bubbles gently sweep the precipitate through the solution, resulting in coagulation by an enmeshment mechanism (sweep coagulation). Consequently compact aggregates are formed, indicating by the high fractal dimension. Flotation is an inherent aspect of the batch electrocoagulation reactor via the production of electrolytic gases. In the reactor, pollutant separation occurs in situ, either by flotation or settling. From the concentration profiles extracted, original kinetic expressions were formulated to quantify these competing removal processes. As current increases, both settling and flotation rate constants increased due to the additional coagulant generation. This faster removal was offset by a decrease in the coagulant efficiency. Consequently a trade-off exists between removal time and coagulant efficiency that can be evaluated economically. A conceptual framework of electrocoagulation is developed from the synthesis of the systematic study to enable a priori prediction. This framework creates predictability for electrocoagulation, which is innovative and original for the technology. Predictability provides insights to knowledge transfer (between batch and continuous), efficient coagulant and separation path, to name just a few examples. This predictability demystifies electrocoagulation by providing a powerful design tool for the future development of scaleable, industrial electrocoagulation water treatment design and operation process.
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Holt, Peter Kevin. "Electrocoagulation unravelling and synthesising the mechanisms behind a water treatment process /." Connect to full text, 2002. http://hdl.handle.net/2123/624.
Full textAbstract:
Thesis (Ph. D.)--University of Sydney, 2003.Title from title screen (viewed Apr. 28, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Dept. of Chemical Engineering, Faculty of Engineering. Degree awarded 2003; thesis submitted 2002. Includes bibliography. Also available in print form.
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Gunukula, Sampath Reddy. "ELECTROCOAGULATION/FLOTATION TREATMENT OF SYNTHETIC SURFACE WATER." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1304363574.
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Andrade, Milton. "Heavy metal removal from bilge water by electrocoagulation treatment." ScholarWorks@UNO, 2009. http://scholarworks.uno.edu/td/1092.
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The purpose of this research was to observe the removal efficiency for copper (Cu), nickel (Ni), and zinc (Zn) using Electrocoagulation (EC) technique in a continuous flow reactor with a synthetic bilge water emulsion; and additionally, to discuss the operation cost of the treatment. The optimal configuration for EC treatment used combined electrodes, aluminum and carbon steel; flow rate of 1 L/min; effluent recycling and 7.5 amps; this optimal configuration achieved 99% of zinc removal efficiency, 70% of both, copper and nickel removal efficiency, and low operation costs. The current intensity did not have significance incidence on the removal efficiency. The analysis of cost per gram of removed contaminant indicated that nickel had an average cost of $1.95 per gram removed, zinc and copper had $0.60 and $0.88 per gram removed, respectively. To develop additional experiments with the EC reactor are required in order to optimize metal removal efficiency.
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Lin, Jack. "Pre-treatment of coal seam water with coagulation and electrocoagulation." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/105358/4/Jack_Lin_Thesis.pdf.
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This thesis examined innovative methods for pre-treatment of coal seam water. In order to prevent scaling and fouling of downstream reverse osmosis membranes we investigated both electrocoagulation and chemical coagulation using aluminium and iron based electrodes and/or coagulants. Application of electrocoagulation was found to significantly reduce the presence of problematic dissolved species such as silica and also alkaline earth ions which potentially can scale membranes and equipment. Chemical coagulation could also remove dissolved silica from simulated coal seam water samples but was found to be relatively ineffective when treating real coal seam water. The future study of electrocoagulation is worthy in order to determine its applicability to a wider range of coal seam water compositions and to minimise costs of use.
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Kuokkanen, V. (Ville). "Utilization of electrocoagulation for water and wastewater treatment and nutrient recovery:techno-economic studies." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526211084.
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Abstract Electrocoagulation (EC) is an emerging technology that combines the functions and advantages of conventional coagulation, flotation, and electrochemistry in water and wastewater treatment. The aims of this work included doing an updated literary review of recent feasible applications of EC, which were found to be plentiful. Since the economic and practical operational key figures related to EC haven’t been extensively mapped out before, this was a prime objective of this part of the work. The aim of the next part of this work was to find new feasible applications for EC in the treatment of water and wastewater. The studied wastewaters included bio- and synthetic oil-in-water emulsions, various industrial nutrient-containing wastewaters, and peat bog drainage water containing humic substances (an interesting and topical problem, especially in Finland). These studies proved the feasibility of EC. In addition, larger-scale experiments were also conducted successfully, thus proving the scalability of the EC process. Extensive economic analyses of the studied EC applications were also done. The operational costs and energy consumption of EC were found to be very low—typically about 0.1–1.0 €/m3 and 0.4–4.0 kWh/m3. It has been forecasted that in the future there will be a shortage of virgin phosphorus. Therefore, another essential purpose of this work was to conduct a preliminary study on the feasibility of using EC for nutrient (especially phosphorus, but also nitrogen) removal and recovery from different types of real wastewater. Specifically, it may be possible to use EC sludges containing notable amounts of phosphorus and nitrogen as additives in granulated bio ash-based fertilizer products for various applications. This is a novel idea and a “hot topic” in the waste utilization sector and in circular and bioeconomyTiivistelmä Elektrokoagulaatio (electrocoagulation, EC) on nosteessa oleva teknologia, joka yhdistää perinteisen koagulaation, flotaation ja sähkökemian hyödyt ja mahdollisuudet vesien ja jätevesien käsittelyssä. Tämän työn ensimmäisenä tavoitteena oli laatia kirjallisuuskatsaus EC:n viimeaikaisista käyttökelpoisista sovelluksista, joita löytyi runsaasti. Koska EC:n toiminnallisia ja taloudellisia avainlukuja ei ole kartoitettu kattavasti aiemmin, tämän tekeminen oli tämän osion tärkein tavoite. Väitöstyön seuraavana tavoitteena oli löytää uusia sovellutuksia EC:lle vesien ja jätevesien käsittelyssä. Tutkittuja vesiä olivat bio- ja synteettisistä öljyistä valmistetut öljy-vesiemulsiot, erilaiset teolliset ravinnepitoiset jätevedet ja humusainepitoiset turvesoiden valumavedet (kiinnostava ja ajankohtainen ongelma, erityisesti Suomessa). EC todettiin käyttökelpoiseksi teknologiaksi näissä kokeissa. Suuremman skaalan kokeilla todistettiin lisäksi EC-prosessin skaalautuvuus. Lisäksi, em. EC-sovellutuksista suoritettiin kattavat taloudelliset analyysit. EC:n käyttökustannukset ja energiankulutus todettiin erittäin pieniksi, tyypillisesti ne olivat välillä 0.1–1.0 €/m3 ja 0.4–4.0 kWh/m3. On ennustettu, että tulevaisuudessa on pulaa neitseellisestä fosforista. Tästä johtuen eräs tämän työn keskeisistä tarkoituksista oli suorittaa alustavia kokeita liittyen EC:n käyttökelpoisuuteen ravinteiden (erityisesti fosfori, mutta myös typpi) poistossa ja talteenotossa aidoista jätevesistä. Erityisesti jatkossa voisi olla järkevää hyödyntää runsaasti fosforia ja typpeä sisältäviä EC-sakkoja lisäaineina rakeistetuissa biotuhkapohjaisissa lannoitteissa eri sovellutuksissa. Tämä idea on uusi ja on jo herättänyt suurta kiinnostusta mm. kierto- ja biotaloussektoreilla
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Willfors, Andreas. "Local Treatment of Water and Sludge Containing Oil in Sweden." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-25146.
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Due to several reasons, treatment methods for a certain waste are oftennot available locally in the waste handling and management industry. This is especially true for regions which are not densely populated. This requires transports, the majority of which consumes fossil fuel. To avoid this, local waste treatment methods need to be developed. In this work it is investigated how treatment of one hazardous waste is done; water and sludge containing oil. Based on sustainability criteria three novel methods are presented that can be conducted locally; mycoremediation, phytoremediation and electrocoagulation. The methods are evaluated in a case study of a recycling company. Mycoremediation and electrocoagulation were found to be suitable in the case study, as long as some criteria are fulfilled. In addition it is shown what barriers exist in law, policies and practices that hinder local treatment of water and sludge containing oil.
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McBeath, Sean T. "Pilot capacity iron electrocoagulation scale-up for natural organic matter removal for drinking water treatment." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60562.
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Canadian remote communities are most often those who are affected by poor water quality and boil water advisories. A major issue is the applicability of traditional water treatment technologies to unconventional applications (small-scale and inaccessible communities). Their inaccessibility presents difficulties for supplying needed chemicals involved in traditional treatment processes such as coagulations and flocculation. Electrocoagulation (EC), an electrochemical process producing coagulant chemicals on-site and on-demand, may be an alternative technology to traditional coagulation suitable for small and remote communities. The following work investigated a continuous iron EC process for natural organic matter (NOM) removal. EC experiments were undertaken in the laboratory at 1.35 and 5 LPM, using synthetic surface water, monitoring the effect of flocculation, metal loading (ML), current density and inter-electrode gap. At both flow rates, flocculation was found to have no effect on the reduction of DOC or UV-abs-254. ML was found to have the greatest effect on both DOC and UV-abs-254 reductions, where the highest ML tested yielded reductions >90% and >60%, respectively. Increases in UV-abs-254 at low ML were found to be due to dissolved residual iron. It was determined that humic acid and chloride functioned as ligands and increased the solubility of iron. Operations were scaled-up to 10 LPM and integrated into a water treatment plant in the community of Van Anda, using raw surface water. Average DOC and UV-abs-254 reductions at the greatest ML were 37.2±4.2% and 54.7±0.9%, respectively. EC was found to have low energy requirements at a pilot-scale, whereby 0.480-0.621 kWh per cubic meter of water treated was required to operate at the conditions that yielded the greatest NOM reductions. Finally, an investigation to determine the current density distribution was undertaken. Current distribution results yielded increased current uniformity with the increase of the inter-electrode gap. This increased uniformity can be attributed to the water velocity profiles in the reactor. Through computational fluid dynamic (CFD) models, it was demonstrated that fluid flow uniformity also increased with an increasing inter-electrode gap. Regions of the electrode that were observed to be occupied by high fluid velocity were also areas yielding greater current density.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Peterson, Mark. "Electrodisinfection of Municipal Wastewater Effluent." ScholarWorks@UNO, 2005. http://scholarworks.uno.edu/td/294.
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To avoid the spread of disease from sewage treatment effluents, pathogenic microorganisms present must be destroyed by one or a combination of disinfection methods. Chlorine remains the predominant disinfectant used although it consumes considerable amounts of energy and has associated exposure risks from production, transportation and storage of this poisonous gas. In addition to bacteria and other objectionable microorganisms, color, suspended and colloidal solids also require removal from water for reuse. Aluminum and iron additions have been used to coagulate and remove non-settleable solids. By electrically dissolving aluminum to form solids-bridging aluminum hydroxide, the water itself can also be disinfected by the effects of electrical fields and its reactions to form disinfectant chemicals and direct destruction of microorganisms in the water. This research investigated the effects of electrical current, time, and chloride concentration on the electrochemical disinfection of sewage treatment plant effluent using aluminum electrodes to substitute for chlorine disinfection.
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Mohammed, Alahmad Suleiman. "Electrochemical and Electroflotation Processes for Milk Waste Water Treatment." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu151309400205639.
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Liu, Han. "CNT-based Electrochemical Filter for Water Treatment: Mechanisms and Applications." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17467306.
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Water treatment is a critical global challenge requires innovated effective solution. Conventional treatment methods includes membrane filtration, adsorption and electrochemical oxidation of organics. This dissertation proposed a new hybrid of the three conventional technologies and investigated the mechanism and application potential for water treatment using carbon nanotube (CNT) based anodic filter. A qualitative reactive transport model consisting of mass transport, adsorption/desorption, electron transfer was developed to understand reaction mechanism and compare the filtration with the batch electrochemical system. The mass transport step is found to be the key advantage (>6-fold) of the electrochemical filtration over the batch system due to convective mass transport through the filter pores. This indicate synergy between the filtration and the electrochemisty. A quantitative model coupling the above three steps was also build to quantitatively simulate the reaction kinetics and probe information about reactive sites. The model simulation was successfully validated by experimental methyl orange oxidation data and was further used to identify kinetics from reactive sites. It was found that two types of reactive sites–the sidewall sites and oxy-defect sits are both reactive for ferrocyanide oxidation with a slightly different overpotential. Also, microscopic flux and steamline plot again verify the convective mass transport enhance reaction kinetics–synergy of the filtration and electrochemistry. To improve potential for organic oxidation applications, the CNT filter was coated with 3.9±1.5 nm bismuth-doped tin oxide (BTO) nanoparticles. In the oxalate oxidation experiments, the current efficiency increased by 1.5–3.5 times and TOC removal increased by 2–8 times after coating. The BTO-CNT anode energy consumption was 25.7 kWh kgCOD-1 at ~93% TOC removal and 8.6 kWh kgCOD-1 at ~50% TOC removal, comparable to state-of-the-art oxalate oxidation processes (22.5–81.7 kWh kgCOD-1). The anode stability also improved by extending the working potential range from 1.4 V of pure CNT to 2.2 V of BTO coated CNT. For inorganic ion removal applications, the CNT filter was coated by a 5.5 ± 2.7 nm layer of TiO2 for arsenic removal. Compared with the conventional adsorption column using granular adsorbents, the TiO2-CNT filter is a highly dispersed nano-system allows forced convective transport through the pores whereas diffusive mass transport dominates and limits kinetics for granular adsorbents. As a result, adsorption kinetics of the TiO2-CNT filter increased by two orders of magnitude due to structure improved site accessibility (20–30 fold), internal convection (4–6 fold) and electrosorption (0.15–2 fold). Groundwater samples containing 44 ppb As were treated by single-pass filtration, and 12500 bed volumes (residence time of 4.5 s; 127 L m-2 h-1; 5.8 mg m-2 h-1). TiO2 filter was successfully regenerated by 5 mM NaOH for both As(III) and As(V).Engineering and Applied Sciences - Engineering Sciences
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Woudneh, Million Bekele. "Mechanisms and factors affecting removal of herbicides by biological filters." Thesis, University of Surrey, 1996. http://epubs.surrey.ac.uk/843258/.
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A critical review of the mechanisms of present water treatment systems including, chlorination, coagulation, filtration, granular and powdered activated carbon adsorption, ozonation and ultraviolet radiation for the removal of herbicides is presented. Rapid selective and sensitive HPLC methods were developed and rigorously validated for the analysis of the selected herbicides. Analysis of atrazine was made using Cl8 cartridges. For raw water containing interferences, extraction of the compound was made on SCX cartridges, followed by solvent exchange on C18 cartridges. A quantitative recovery of virtually 100% of the compound was achieved using C18. While the double cartridge extraction of the compound gave a recovery of about 89%. Previously developed methods for 2,4-D and MCPA were rigorously validated for the extraction and analysis of 2,4-D and MCPA. A quantitative recovery of usually greater than 90% was achieved for both compounds using Cl8 cartridges. For the extraction of paraquat different extraction systems including, reversed phase on C8 and C18, ion-paired reversed phase on C18, and cation exchange on SCX, CBA, and CN were investigated. A quantitative recovery, usually greater than 90%, of the compound was obtained using CN and CBA cartridges. The methods were then successfully used for the evaluation of the removal efficiency and establishment of mechanisms of removal of herbicides by biological filters at bench and pilot scale. Four herbicides belonging to three broad chemical categories were studied. The data presented in this study demonstrated that biological filters are very efficient in removing certain classes of herbicides. 2,4-D and MCPA were consistently removed to below a detection limit of 0.1 mug/1 for an influent concentration of 3-11 mug/1. Process variables such as flow rate, bed depth and contact time were investigated for the efficient removal of these herbicides. Seasonal variations in performance were observed and possible explanations proposed. A series of experiments was undertaken to establish .mechanisms of removal. Quantitative recovery of the herbicides from the river water proved that the processes in the filter bed as opposed to the processes in the water were responsible for removal of the herbicides. It was clear from the investigation of the adsorption of the herbicides both on the sand and organic and inorganic dirt that adsorption on these surfaces was not the main reason for removal. Filter maturation experiment showed that the presence of microorganisms in the bed is a precondition for the removal of herbicides. A depth experiment for the removal of 2,4-D showed that superficial efficient zone of removal imitates the distribution of microbial density. This evidence confirms the significance of microorganisms for the removal of herbicides by the filter bed. The ultimate proof of the biodegradation of 2,4-D by microorganisms in the filter bed was the identification of the biodegradation product 2-chlorophenol as predicted by the metabolic pathways of the compound. Filter design modifications using activated carbon were made to accommodate the removal of 'non-biodegradable' herbicides. A sandwich sand / GAC / sand filter was investigated. Filter efficiency for this arrangement was determined and short-comings were identified and a possible solution in the form of a double GAC sandwich is suggested.
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Hansson, Henrik. "Reduction of Pollutants in Stormwaterand Processwater from the WoodIndustry by Electrocoagulation." Thesis, University of Kalmar, School of Pure and Applied Natural Sciences, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hik:diva-2530.
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Although wood floor production does not use water in the production process, water consumptionis related to cleaning and washing of floor and machineries in different steps of the process line,which generate a number of small flows that are highly polluted.Besides this, the industry has a need to store large amounts of wood outside to be able to havecontinuity in the production. This takes up a lot of space outdoors and once it rains the water thathas been in contact with wood, oil and metals forms stormwater, which transports pollutants.Stormwater has for a long time not been seen as a problem and has often been discharged intorecipient water bodies without any treatment. During cold seasons, this also involves snowmelt thatcan transport high concentrations of different pollutants.This report describes the composition of process- and stormwater from a wood floor industry inNybro, Sweden regarding parameters such as COD, phenol, tannin and lignin. The concentrationsof phenols in the stormwater were found in a range considered toxic to marine life.Regarding the process water, high values was found for COD (Chemical Oxygen Demand) and forother substances and elements potentially toxic (e.g. formaldehyde, wood resins, detergents andmetals). If these waters are directly released to a sewage treatment plant without any pre-treatmentprocess it can disturb the plant treatment efficiency; if released to a recipient water body, it cancause oxygen deficiency and consequently, death to marine life.The possibility of reducing the levels of pollutants through the use of electrocoagulation has beenexamined in this study. This has been done both for process water and stormwater from the woodfloor industry. A 250 ml batch unit for electrocoagulation EC was setup with iron (Fe) andaluminium (Al) electrodes for treating process water and stormwater. The results show that the ECprocess can reduce COD concentration from stormwater at least 70%. On the other hand, lessefficiency of EC for treating process water was observed.A method for simulating a snowmelt period in lab scale was also developed. Snow collected from awood floor industry was melted according to real temperature and the quality of these samples hasthen been compared to on-site samples of stormwater
Development of an integrated approach for industrial wastewater and stormwater management in the wood-industry sector
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de, Farias Lima Flávia [Verfasser], Peter [Gutachter] Krebs, Stefan [Gutachter] Stolte, and Reza Mohammad [Gutachter] Malayeri. "Oilfield produced water treatment with electrocoagulation / Flávia de Farias Lima ; Gutachter: Peter Krebs, Stefan Stolte, Reza Mohammad Malayeri." Dresden : Technische Universität Dresden, 2019. http://d-nb.info/1226942407/34.
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Hansson, Henrik. "TREATMENT OF WASTEWATER GENERATED BY WOOD-BASED DRY INDUSTRIES: ADVANCED OXIDATION PROCESSES & ELECTROCOAGULATION." Doctoral thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-36437.
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Wood is a material with an enormous number of applications. For decades, the development of wastewater treatment technologies tailored for the wood sector has focused on those industries that have water as an integral part of the industrial production, such as paper and pulp. However, there is a large and potentially growing sector that has been neglected, which is formed by industries in which water is not part of their production line, as for example, the wood floor and furniture industries (named wood-based dry industries). These industries still produces relatively low volumes of highly polluted wastewaters, with COD up to 30,000 mg/L, due to cleaning/washing procedure (named cleaning wastewaters). These cleaning wastewaters are often sent to the municipal wastewater treatment plant after dilution with potable water. Once there, recalcitrant pollutants are diluted and discharged into recipient water bodies or trapped in the municipal wastewater sludge. Another type of contaminated water these “dry industries” often generate in high volumes, and which is usually discharged with no previous treatment, is storm-water containing contaminants that have leached from large wood storage areas. The overall aim of this thesis was to increase the level of knowledge and competence and to present on-site wastewater treatment options for wood-based dry industries using the wood floor industry as a case-study, with a focus on combined treatment methods and solutions applicable to both the cleaning wastewater and storm-water. Among the treatment technologies investigated, electrocoagulation was studied both as a standalone treatment and combined with sorption using activated carbon. The combined treatment achieved a COD reduction of approximately 70%. Some advanced oxidation processes (AOP) were also studied: a COD reduction of approximately 70% was achieved by photo-Fenton, but the most successful AOP was ozone combined with UV light, were a COD reduction around 90% was achieved, with additional improvement in the biodegradability of the treated effluent. Ozone also proved to be effective in degrading organic compounds (approximately 70% COD reduction) and enhanced the biodegradability of the storm-water runoff from wood storage areas. The results have shown that the application of ozone can be considered an option for treatment of cleaning wastewaters and possibly for storm-water biodegradation enhancement.Trä är ett material med ett stort antal möjliga användningsområden. Inom träindustrin har utvecklingen av vattenbehandlingsmetoder varit inriktat på de branscher som har vatten som en del av produktionen, såsom papper- och massaindustrin. Men det finns en stor och potentiellt växande sektor inom träindustrin som har försummats, den utgörs av industrier som inte har vatten som en del av produktionen, t.ex. trägolv och trämöbel industrier. Trots detta så producerar dessa industrier fortfarande relativt kraftigt förorenade avloppsvatten med t.ex. COD-värden upp till 30000 mg/l men i relativt låga volymer. Dessa avloppsvatten uppkommer vid rengöring av maskiner och städning av lokaler, varefter de oftast efter utspädning med dricksvatten skickas till det kommunala reningsverket. Väl där späds det förorenade vattnet vidare ut med annat inkommande vatten men passerar dock till stor del obehandlat och släpps ut i mottagande vattendrag eller så fastnar föroreningarna i avloppsslamet. Dagvatten är en annan typ av förorenat vatten från dessa "torra industrier" som ofta genereras i stora volymer och innehåller föroreningar som lakats från de trämaterial som förvaras i de stora upplag som ofta förekommer vid denna typ av industrier. Det övergripande syftet med avhandlingen var att öka kunskapen och kompetensen för att kunna miljömässigt riktigt och ekonomiskt billigt behandla industriavloppsvatten lokalt på plats inom trävaruindustrin, genom att använda en trä-golvsindustri som fallstudie. Fokus lades på kombinerade behandlingsmetoder och lösningar som skulle kunna vara lämpliga både för industriavloppsvatten och dagvatten. Ett antal behandlingstekniker har undersökts; elektrokoagulering studerades både som en fristående behandling och i kombination med aktivt kol. Den kombinerade behandlingen gav en COD-reduktion på ungefär 70 %. Flera avancerade oxidationsprocesser (AOP) studerades också, och en COD-reduktion på cirka 70% uppnåddes med en kombination av UV-ljus och Fenton behandling. Den mest framgångsrika behandlingen var ozon i kombination med UV-ljus där en COD-reduktion runt 90 % uppnåddes varvid en avsevärd förbättring av den biologisk nedbrytbarhet på det behandlade avloppsvattenet erhölls. Ozon visade sig också vara effektivt för nedbrytning av organiska föreningar (ca 70% COD reduktion) och förbättrade den biologiska nedbrytbarheten av föroreningarna i dagvattnet från den studerade industrin. Resultaten har visat att ozon kan anses vara ett lämpligt alternativ för att behandla industriavloppsvatten inom trävarusektorn och möjligen för att öka den biologiska nedbrytbarheten av dagvattnet från dessa industrier
Integrated Approach for Handling of Industrial Wastewater and Stormwater
Triple Helix Collaboration on Industrial Water Conservation in Småland and the Islands
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Baudequin, Clément. "Conception d'une unité mobile pour le post-traitement d'eau utilisée pendant des opérations d'extinction d'incendie." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2011. http://www.theses.fr/2011ECAP0045/document.
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L’extinction de feux de liquides inflammables sur des installations industrielles telles que les dépôts de carburant ou les raffineries entraîne l'utilisation de milliers de mètres cubes d'eau, composé majeur des mousses anti-incendie. Ces dernières contiennent généralement des tensioactifs hydrocarbonés ainsi que des tensioactifs fluorés qui se retrouvent dans les eaux d'extinction, ainsi que les suies et les restes de solvants. Les tensioactifs fluorés jouent un rôle clé dans l'efficacité des mousses anti-incendie en raison de leur nature chimique particulière. En raison de la présence des tensioactifs fluorés, le traitement actuel de l'eau d'extinction d'incendie est l'incinération dans des incinérateurs haute température et résistant aux halogènes. Les tensioactifs sont des composés amphiphiles qui ont comme propriétés d'abaisser la tension superficielle de l'eau et de former des agrégats en solution : les micelles. Les tensioactifs peuvent également s'adsorber aux interfaces ainsi qu'aux surfaces solides, et éventuellement y former des agrégats de surface, analogues aux micelles en solution. L’objectif industriel de la présente thèse est de proposer une unité mobile de traitement de ces eaux afin de concentrer les composés fluorés et limiter les volumes à incinérer. Les critères de sélection des procédés que nous avons retenus sont les suivants : compacité, peu ou pas de produits chimiques ou solides nécessaires. L’objectif scientifique de ce travail est de mieux comprendre le comportement de ces composés au cours des procédés d’électrocoagulation/filtration et d’osmose inverse. Des essais préliminaires ont été réalisés et ont permis de choisir les procédés suivant : l'électrocoagulation couplée à la filtration comme prétraitement pour séparer les particules en suspension et les traces d’émulsions éventuelles de la phase aqueuse et l'osmose inverse comme traitement pour concentrer les tensioactifs fluorés. A l'échelle du laboratoire, l'électrocoagulation, permettant le retrait de la matière en suspension, a été optimisée pour des eaux d'extinction d'incendie pilotes et un mécanisme a été proposé. L'efficacité de ce procédé a ensuite été vérifiée sur un pilote industriel. L'osmose inverse d'eaux d'extinction d'incendie pilotes pré-traitées par électrocoagulation/filtration a montré de forts taux de rétention du tensioactif fluoré. Une comparaison de différents matériaux membranaires a été réalisée sur un module d’osmose inverse plan avec des solutions modèles. Des essais de filtration de longue durée, à l’échelle pilote, ont permis de suivre l’évolution de la rétention des tensioactifs et du flux de perméat. Ces données ont été utilisées pour réaliser le dimensionnement d’une unité mobile de post traitement d’eau d’extinction d’incendie. Les perspectives de ce travail sont les suivantes : La prise en charge de la réalisation d’une unité mobile devrait être menée par un partenaire de DuPont de Nemours qu’il reste à identifier. L’étude sur la modification de l’état de surface des membranes est poursuivie dans le cadre d’une nouvelle thèse et permettra à terme de mieux choisir les conditions opératoires de filtration et de nettoyage au cours des procédés membranaires et ainsi d’améliorer les performances du procédéExtinguishment of large solvent fire leads to the production of fire fighting water, which are collected thanks to the design of industrial infrastructures. Depending on the nature of the firefighting foam used, the resulting water may require the removal of fluorinated surfactants potentially present. After decantation of the organic phase, fire fighting waters essentially contain surfactants. Surfactants are amphiphilic chemicals having the ability to lower both interfacial and surface tensions by adsorbing in an oriented fashion at interface. Surfactant can form micellar aggregates in solution and on interfaces under certain conditions, and have a pronounced influence on interfacial phenomena. Hence, before considering any water treatment process, interfacial science and surfactant were introduced. This work has a dual purpose. The industrial purpose is to provide an economically viable alternative to water incineration. The foreseen unit will have to be mobile and able to extract fluorinated surfactants from water at a rate of 1-4.5 m3h-1 (20,000 m3 in 4-6 months). The scientific purpose of this work is the study of the behavior of surfactants in the context of water treatment processes. The state of the art of relevant water treatment processes and an experimental screening with real firefighting water permitted to identify two steps as likely to fit the constraints of a mobile unit: electrocoagulationfiltration coupled with reverse osmosis. The electrocoagulation process followed by filtration was applied to pilot, model and industrial firefighting waters. This process was found to remove efficiently the unwanted turbidity from pilot firefighting waters. Current knowledge about the separation mechanisms of small organic molecules in reverse osmosis has been reviewed, and rejection as well as flux decline were related to membrane, solution, and solute properties. Polyamide and cellulose acetate membrane materials were screened in a flat sheet cell. The stabilities of rejection and flux decline were confirmed during longer tests (several days) on an industrial pilot with the most appropriate membrane. A final design study confirmed the possibility to combine electrocoagulation-filtration and reverse osmosis to treat firefighting waters
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Reiss, Charles Robert. "MECHANISMS OF NANOFILTER FOULING AND TREATMENT ALTERNATIVES FOR SURFACE WATER SUPPLIES." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3422.
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This dissertation addresses the role of individual fouling mechanisms on productivity decline and solute mass transport in nanofiltration (NF) of surface waters. Fouling mechanisms as well as solute mass transport mechanisms and capabilities must be understood if NF of surface waters is to be successful. Nanofiltration of surface waters was evaluated at pilot-scale in conjunction with advanced pretreatment processes selected for minimization of nanofilter fouling, which constituted several integrated membrane systems (IMSs). Membrane fouling mechanisms of concern were precipitation, adsorption, particle plugging, and attached biological growth. Fouling was addressed by addition of acid and antiscalent for control of precipitation, addition of monochloramine for control of biological growth, microfiltration (MF) or coagulation-sedimentation-filtration (CSF) for control of particle plugging, and in-line coagulation-microfiltration (C/MF) or CSF for control of organic adsorption. Surface water solutes of concern included organic solutes, pathogens, and taste and odor compounds. Solute mass transport was addressed by evaluation of total organic carbon (TOC), Bacillus subtilis endospores, gesomin (G), 2-methlyisoborneol (MIB), and threshold odor number (TON). This evaluation included modeling to determine the role of diffusion in solute mass transport including assessment of the homogeneous solution diffusion equation. A cellulose acetate (CA) NF was less susceptible to fouling than two polyamide (PA) NFs. NF fouling was minimized by the addition of monochloramine, lower flux, lower recovery, and with the use of a coagulant-based pretreatment (C/MF or CSF). NF surface characterization showed that the low fouling CA film was less rough and less negatively charged than the PA films. Thus the theory that a more negatively charged surface would incur less adsorptive fouling, due to charge repulsion, was not observed for these tests. The rougher surface of the PA films may have increased the number of sites for adsorption and offset the charge repulsion benefits of the negatively charged surface. The addition of monochloramine significantly reduced biodegradation and integrity loss of the CA membrane. PA membranes are inherently not biologically degradable due to their chemical structure. Monochloramination reduced the rate of fouling of the PA membrane but resulted in a gradual increase in water mass transfer coefficient and a decrease in TDS rejection over time, which indicated damage and loss of integrity of the PA membrane. Based on surface characterization by X-ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectrometry (FTIR), the PA membrane degradation appeared to be chemically-based and initiated with chlorination of amide nitrogen and/or aromatic rings, which ultimately resulted in disruption of membrane chemical structures. The recommended Integrated Membrane System to control fouling of a surface water nanofiltration system is CSF monochloramine/acid/antiscalent„³monochloramine-tolerant NF. This IMS, at low flux and recovery, operated with no discernable fouling and is comparable to a groundwater nanofiltration plant with cleaning frequencies of once per six months or longer. A significant portion of the organic solutes including total organic carbon (TOC) passing through the membranes was diffusion controlled. Permeate concentration increased with increasing recovery and with decreasing flux for both PA and CA membranes. The influence was diminished for the PA membrane, due to its high rejection capabilities. Total rejection of spores used as pathogen surrogates was not achieved as spores were indigenous and high spore concentrations were used in all challenge studies; however, Integrated Membrane System spore rejection exceeded credited regulatory rejection of similar sized microorganisms by conventional treatment by several logs. Spore rejection varied by NF but only slightly by MF as size-exclusion controlled. There was no difference among spore rejection of IMS with and without in-line coagulation. Consequently, these results indicate membrane configuration (Hollow fiber>Spiral Wound) and membrane film (Composite Thin Film>CA) significantly affected spore rejection. Geosmin and methylisoborneol have molecular weights of 182 and 168 respectively, and are byproducts of algal blooms, which commonly increase taste and odor as measured by the threshold odor number (TON) in drinking water. Although these molecules are neutral and were thought to pass through NFs, challenge testing of IMS unit operations found that significant removal of TON, G and MIB was achieved by membrane processes, which was far superior to conventional processes. A CA NF consistently removed 35 to 50 percent of TON, MIB, and G, but did not achieve compliance with the TON standard of 3 units. A PA NF provided over 99 percent removal of MIB and G. Challenge tests using MIB and G indicated that size-exclusion controlled mass transfer of these compounds in NF membranes.Ph.D.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Environmental Engineering
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Geroni, Jennifer. "Rates and mechanisms of chemical processes affecting the treatment of ferruginous mine water." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/19120/.
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This thesis presents the results of research undertaken into the rates of Fe(II) oxidation and CO2 stripping from ferruginous mine drainage. It also provides new insight into the applicability of Vertical Flow Reactors (VFRs) to the treatment circumneutral waters. Batch-wise experiments were used to determine Fe(II) oxidation rates in the field. The data collected were used to show that values for the rate constant k1 were up to 3 orders of magnitude greater at the field sites than would be predicted from previously published laboratory studies. A methodology was also developed for determining k2 (the heterogenous oxidation rate constant) in the field. The results of field based monitoring of aeration cascades as well as batchwise CO2 stripping experiments conducted using waters of varying chemistry were combined with geochemical modelling to demonstrate the evolution of the chemistry in these systems over time. The aeration cascades were shown to remove approximately 50% of the dissolved CO2 initially present but this was not shown to have an appreciable effect on mine water treatability. Continued removal of the residual CO2 fraction by mechanical aeration resulted in the elevation of pH by up to 2 units. Trials of pilot scale Vertical Flow Reactors (VFR) at two sites in South Wales showed that rapid decreases in bed permeability over time make these systems unsuitable for deployment in the treatment highly net alkaline waters. As a result of adverse weather conditions and other technical difficulties there was insufficient data collected to determine the performance of these systems under net acid conditions. Qualitative observations suggest however that Fe removal was taking place at a significantly higher rate than would be seen in settling lagoons under the same conditions.
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Zhong, Shifa. "Permanganate Reaction Kinetics and Mechanisms and Machine Learning Application in Oxidative Water Treatment." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1618686803768471.
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Ashraf, Syeda Nishat. "Applicability of coagulation technologies for high-turbidity coal seam gas water treatment." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/127500/1/Syeda_Ashraf_Thesis.pdf.
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This project developed new strategies to facilitate reuse of water from the coal seam gas (CSG) industry. Both chemical coagulation and electrocoagulation were examined for their ability to protect downstream reverse osmosis (RO) desalination systems from detrimental fouling and scaling. Electrocoagulation in particular was highly effective at removing dissolved silicates, alkaline earth ions and suspended solids; thus RO operation was expected to be improved. In addition the purification of resultant brine was demonstrated, thus potentially enabling the recovery of salt as a product. It was recommended to scale-up electrocoagulation testing to pilot plant.
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Al, Tahmazi Talib. "Characteristics and mechanisms of phosphorus removal by dewatered water treatment sludges and the recovery." Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/105255/.
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The use of novel industrial by-products (IBPs) to remove phosphorus (P), instead of high-cost P removal techniques, is one of the sustainable solutions to protect aquatic life from excessive P discharges. One of such IBPs is dewatered drinking water treatment works sludges generating from using aluminium or iron salts as coagulant during the drinking water treatment process. Previous studies have shown that the sludges hold promise as a novel adsorbent for the removal of P from wastewaters; however, comprehensive investigation into factors affecting the P removal and the recovery is lacking. Therefore, the main aim of this study is to contribute to a mechanistic understanding of P removal and retention by dewatered water treatment sludge (DWTS), and the associated coagulant recycling and P recovery from the P-saturated sludge used as substrate in a constructed wetland system. Seventeen DWTSs were collected from different areas in the UK to study the combined effect of sludge inherent properties and solution chemistry; and the P equilibrium and kinetic adsorption behaviour using batch experiments. Results revealed that the metal content (Al, Fe, Aloxalate and Feoxalate) and specific surface area components had the most significant explanation for the variance of: (i) P-uptake at different initial P concentrations; (ii) the adsorption maxima; and (iii) the Freundlich constant. Overall, giving the combined effect of intrinsic sludge properties and solution chemistry, dewatered waterworks sludges with high reactive metal content (Al and Fe), Ca and SO42- ions, and total specific surface area, would be the best choice for P retention in practical applications. Phosphorus retention by two Al- and two Fe-DWTS were modelled under various operation conditions of hydraulic retention time and influent P concentration, using a continuous feeding system. Four design equations for P retention were developed and these successfully predicted discrete P retention, maximum P loaded to the sludge, accumulative amount of P retention, and lifespan at the required P saturation degree. The model results revealed that the lifespan of ferric sludge is about four years to reach its saturation point, if the flow rate of 190 (l/capita.d) and inflow P concentration of 5 mg/l are used. IV With regards to coagulant recycling and P recovery using electrodialysis (ED) technology, P saturation degree influenced negatively on Fe and P recovery where their percentages dropped from 70 ± 8%, 49 ± 3% to 17 ± 2, 6 ± 1% when P saturated sludge increase from 0% to 100% respectively. The normalised values of recovered Fe to permeated dissolved organic carbon (DOC) were between 29 and 290. Most of the recovered coagulants were comparable in performance with commercial coagulant in term of DOC removal (42 to 59%), Turbidity, and UV254 absorbance. Overall, the results have shown that DWTS has great potential not only for P removal but also for coagulant and P recovery. However, further research is needed before the developed models can be applied at field scale, and also to enhance the ED recovery for further benefits.
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Makris, Konstantinos Christos. "Long-term stability of sorbed phosphorus by drinking-water treatment residuals mechanisms and implications /." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0006635.
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Hao, Wei. "A potential energy-saving heat treatment for re-circulated irrigation water and its biological mechanisms." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/49596.
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Heat pasteurization is an effective water treatment to address the emerging plant pathogen issue associated with increased water recycling practices in the ornamental horticulture industry. The current protocol that recommends treating water at 95"C for 30 s, however, faces two major challenges: its energy cost and environmental footprint. We hypothesized that temperature required to inactivate major pathogens in re-circulated water may be substantially lowered from 95"C with extended exposure time. The goal of this study was to test this hypothesis and make this water decontamination technology economically more attractive while reducing its environmental impact. Specific objectives were to (1) examine the effect of water temperature on the survival of Phytophthora and bacterial species, two major groups of plant pathogens in water recycling systems, and (2) elucidate the underlying biological mechanisms by which plant pathogens are killed at those temperatures. Lab assays were performed to determine the survival of zoospores and chlamydospores of P. nicotianae, and oospores of P. pini as well as seven bacterial species after heat treatments at given periods of time. Greenhouse experiments were conducted to determine the applicability of the lab assay data to the real world using annual vinca (Catharanthus roseus) and P. nicotianae as a model system. The results of these studies indicated that the water temperature required to eliminate Phytophthora and bacterial species can be lowered to 48"C from 95"C if treatment time extends to 24 h. Two major steps were taken to elucidate the underlying biological mechanisms. Firstly, a scheme based on the DNA fingerprint and sequence analysis was developed for characterizing bacterial species in irrigation water, after comparing two typing strategies, three sample concentration methods, and evaluating conditions in denaturing gradient gel electrophoresis (DGGE) profiling. Bacterial species detected by culture-dependent and -independent strategies were rather different. The greater bacterial diversity was detected when water samples were concentrated by using both methods than centrifugation or filtration alone. As for DGGE profiling, 40 to 60% denaturant concentrations at 70 V for 16 h revealed the highest bacterial diversity. Secondly, water samples were taken from an irrigation reservoir in a local nursery and analyzed for bacterial diversity following heat treatments at 42 and 48"C. After these heat treatments "-proteobacteria, "-proteobacteria, and Firmicutes became dominant which presents a substantial shift of bacterial community structure compared to those in the control water at 25"C. Among the dominant in treated water were Bacillus, Pseudomonas, Paenibacillus, Brevibacillus, and Lysobacter species, which may have potential biocontrol activities against plant pathogens. This study provided the scientific basis for developing a more energy-efficient and environmentally sound heat pasteurization protocol for water decontamination.Ph. D.
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Barnes, Andrew. "Rates and mechanisms of Fe(II) oxidation in a passive vertical flow reactor for the treatment of ferruginous mine water." Thesis, Cardiff University, 2008. http://orca.cf.ac.uk/54812/.
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This thesis presents the methodology and results of research undertaken into the rates and mechanisms of iron oxidation both in field and laboratory environments. The field based aspects of the research entailed the collection and analysis of hydrological, hydrogeochemical, and mineralogical data from two parallel treatment systems. Both systems were treating identical ferruginous, circum-neutral, coal-mine drainage, from the Taff Merthyr site, South Wales. During this study a novel pilot scale passive Vertical Flow Reactor (VFR) was trialled against a conventional settlement lagoon and the performance of both systems was compared. The second research aspect focuses on the determination of heterogeneous Fe(II) oxidation rates under laboratory conditions. Experiments were carried out under varying pH, and catalytic surface concentration and type. An analytical method was developed which allowed for the determination of both dissolved and sorbed Fe(II). The results of the field study have shown that the VFR system is capable of removing Fe at a rate greatly in excess of a conventional settlement lagoon. This therefore drastically reduces the treatment area required. In addition, due to the heterogeneous method by which the VFR operates (passing mine- water down through a bed of ochre solid), highly efficient manganese removal was also achieved. The laboratory study has shown that significant catalysis of Fe(II) oxidation can be achieved under mildly acidic pH conditions making Fe(II) oxidation (and therefore passive mine-water treatment) feasible under these conditions. Evidence is also presented for the adsorption of non-oxidisable Fe(II) onto Fe(III) (hydroxy)oxides under mildly-acidic pH conditions. A comparison was then made between field and laboratory results and a conceptual model was produced to describe the observed adsorption and oxidation characteristics.
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Shao, Hong Xiang. "DEVELOPING ORGANIZATIONAL DYNAMIC CAPABILITIES IN PROJECT-BASED INTEGRATED SOLUTION : A Study of Servitization in Chinese Water Treatment Industry." Thesis, Umeå universitet, Företagsekonomi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-160755.
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Manufacturing firms seeking to create and extend competitive advantage are striving to include more services into their offerings. Meanwhile, there are research gaps such as how frontline service providers influence organizational dynamic capabilities and how organizational dynamic capabilities can be developed in servitization need to be systematically studied and explicitly explained. Although service is characterized by service providers applying own knowledge and skills for the benefits of customers, service providers are traditionally looked as pure decision takers. The influence of service providers upon organizational dynamic capabilities is habitually underestimated. Because solution is classified as the most common offering in servitization and project-based integrated solution is an essential category in solution the study launched in this thesis focuses on firms providing project-based integrated water treatment solutions. The attempt to fill identified research gaps is carried out in three steps by answering hereinafter questions: What roles the frontline service providers, project manager and team members, play in project-based integrated solution? How service providers can influence organizational dynamic capabilities in project-based integrated solution? What mechanisms service providers can leverage to develop dynamic capabilities in project-based integrated solution? This thesis builds on the intersection of dynamic capability and servitization literatures and is complemented by insights from project-based organization researches. Knowledge about the micro-foundations of dynamic capabilities in project-based integrated solution is generated from literature review. Data on potential strategic roles of service providers, their influence on organizational capabilities, and mechanisms to develop capabilities are collected in semi-structured interviews. In this thesis, the strategic roles which project manager and team members play, and their respective influences upon organizational capabilities are differentiated. Meanwhile, data in relation with the service cocreators on customer side are also collected and analysed, and their influence on project performance is discussed. Overall, this study is qualitative in nature and the theory development follows a deductive in combination with inductive approach. This study generates at least four theoretical contributions: firstly, it classifies the roles frontline service providers could play; secondly, it deepens the understanding of the influence frontline service providers could have on organizational capabilities; thirdly, it explores the micro-foundations of dynamic capabilities in servitization; and fourthly, it provides preliminary findings about the influence of service co-creators. This study also brings multiple managerial contributions for example providing insights for managers to reconsider firm organizational structure, decision-making processes, human resource and knowledge assets management in servitization. Additionally, this study suggests that there are applicable mechanisms for firms to develop capabilities in project-based integrated solution. Finally, this study emphasizes that, to improve project performance, managers should also put more efforts on developing service cocreators’ capabilities.
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Singh, Shivashkar. "The biological treatment of metalworking fluids : insights into carbon removal mechanisms and integration with biocide toxicity mitigation strategies." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:999c3738-fe5c-4e41-a7f3-83b0cffe7ea9.
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The biological treatment of metalworking fluids (MWFs) is a cost effective alternative to conventional waste disposal processes. While research has proven that this process is capable of treating large volumes of wastes with high organic concentrations, there are uncertainties about the mechanisms by which the treatment occurs, and there are limitations that must be overcome. There is a need to understand the importance of the mechanisms by which carbon (and hence COD) is removed from the wastewater. This will allow for waste practitioners to make better decisions for optimizing the process, and for disposing of waste (i.e sludge) that is generated. The biological treatment process is also susceptible to biocides present within formulations. These compounds either need to be removed before the treatment process, or the bioreactors need to be made more resistant to them to ensure that their presence does not hinder the reactor functioning. This study aims to answer the uncertainties about the carbon removal mechanisms involved in the treatment of oil-containing MWFs. In the first experimental chapter, it is shown that the predominant mechanism of carbon removal is oil/water separation induced by emulsifier degradation, and hence the bioprocess treatment rate is significantly affected by the biodegradability of surfactants and by the presence of cations found naturally in the water that used to prepare the emulsions. The study then provides insights into the potential that coagulation and coalescence has for removing inhibitory components commonly found in MWFs. Coagulation and coalescence is shown to effectively remove biocides with low aqueous solubility (iodopropynyl butylcarbamate) and those that partition themselves into the oil phase (o-phenyl phenate and its sodium salt). Finally, to improve the resistance of reactors to inhibitory compounds, factors influencing the development of fixed-film reactors are investigated. A micro-cosmic system is used to study the both physico-chemical effects and nutritional factors on the development of biofilm reactors. It is shown that biofilm yields can be controlled through pH adjustment, and that these yields are maximized with phosphate stimulation and ammonium limitation. It is then shown that fixed-film reactors are able to treat metalworking fluids even under conditions deemed to be inhibitory. In summary, this project provides insights into further understanding and enhancing the biological treatment of MWFs.
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Eveborn, David. "Bed filters for phosphorus removal in on-site wastewater treatment : Removal mechanisms and sustainability." Licentiate thesis, KTH, Land and Water Resources Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12048.
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For many surface waters, phosphorus (P) leaching is a serious problem that should be minimized to prevent eutrophication. In Sweden there is a demand for physical and technical development of high-performance P removal techniques to reduce phosphorus leaching from on-site wastewater treatment systems to the Baltic Sea. However, although these systems are designed to reduce eutrophication there are also other environmental impacts to be considered when implementing them in on-site systems; energy use and global warming potential are two examples. This study has investigated several bed filter materials (reactive media and natural soils) for their total environmental impact (in commercial applications) as well as for the predominating chemical phosphorus removal mechanisms. The use of life cycle assessment revealed that several reactive bed filters are relatively energy-consuming due to the material manufacturing process. Characterization of phosphorus compounds in used reactive media provided evidence for calcium phosphate precipitation as the predominating P removal mechanism in alkaline filter materials. However, in soil treatment systems with noncalcareous soils, batch experiments and extractions suggested that aluminium compounds were important for P removal. According to mass balance calculations that compared accumulated P with the estimated P load in a soil treatment system, the long term P removal capacity was very low; only 6.4 % of the applied phosphorus had been removed during 16 years of operation.
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Eakin, Katharine. "NEUROPROTECTIVE EFFECTS OF POSTINJURY LITHIUM TREATMENT: DETERMINING THE OPTIMAL DOSING PARADIGM AND ASSESSING POTENTIAL MECHANISMS OF ACTION." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2174.
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Traumatic brain injury (TBI) has a dramatic impact on our society in terms of mortality, morbidity, and inherently high financial costs. Formidable research efforts are being addressed to the identification of neuroprotective agents capable of ameliorating the neurological outcome after TBI. Preclinical studies have recently demonstrated lithium to be a promising neuroprotective agent for both acute ischemic brain injury and chronic neurodegenerative disease. In light of these encouraging data, we designed a lateral fluid-percussion injury (FPI) study aimed at investigating the role of early post-traumatic administration of lithium as a strategy for reducing TBI-induced motor and cognitive deficits. The optimal dose of this agent and the time window for its administration have been determined on the basis of data derived from the assessment of motor and cognitive functioning in experimental animals, as well as from the stereological quantification of neuronal survival (PID 7) within the CA3 and hilar regions of the hippocampus ipsilateral to the FPI. In addition, we attempted to elucidate the mechanisms underlying the neuroprotective properties of this drug via western blot analysis of levels of the pro-apoptotic marker caspase-3 (PID 1, 7) and two neuroplasticity markers, growth associated protein-43 (GAP-43) and brain-derived neurotrophic factor (BDNF) (PID 1, 7, 21). Our findings indicate that low-dose lithium chloride (0.125 or 0.25 mmol/kg), given either 30 min or 8 hr after lateral FPI significantly ameliorates injury-induced cognitive and motor impairment. Specifically, cell survival in the CA3 region of the hippocampus of the injured lithium-treated animals (but not in the hilus) was significantly increased compared to injured vehicle-treated animals. Western blot analyses revealed a significant increase in GAP-43 levels on PID 7 in injured animals when treated with lithium, indicating a possible mechanism for lithium-induced neuroprotection. In contrast, BDNF levels were relatively unchanged until PID 21, and caspase-3 activation was not observed at all, suggesting that these proteins play less significant roles in the observed neuroprotective effects of lithium treatment after lateral FPI. Early administration of lithium, within 8 hours after TBI, holds promise as an effective therapy to ameliorate postinjury neurobehavioral deficits and warrants further investigation in clinical TBI studies.
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Zhang, Ziyang. "Facile Synthesis of ZnWO4/Bi2WO6, FeWO4/Bi2WO6, and TiO2/Bi2WO6 Nanocomposites via a Modified Pechini Sol-gel Method and their Photocatalytic Performance for Bisphenol A Degradation." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613753216804191.
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Rezai, Bidakhavidi Caminde. "Nouvelles solutions de préparation et d'activation des surfaces : assemblages époxy-fonte." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCA021/document.
Full textAbstract:
Les revêtements organiques déposés en surface de tuyaux en fonte ductile ont pour vocation d’assurer une protection (notamment la résistance chimique, la tenue à la corrosion) vis-à-vis des effluents agressifs transportés. Pour assurer l’adhérence entre le revêtement (époxy) et son substrat, une préparation de surface est souvent nécessaire. Parmi les procédés conventionnels, le grenaillage est la solution la plus utilisée. Simple à mettre en œuvre et d’efficacité prouvée, il permet d’assurer le décapage de la surface tout en générant une rugosité adaptée. Si la solution est approuvée, des questions subsistent néanmoins quant à l’influence respective de la topographie et de la physico-chimie des surfaces. De plus, encouragées par les nouvelles réglementations environnementales, de nouvelles techniques de préparation de surface se développent.Le travail présenté s’est alors attaché à évaluer l’effet de nouvelles techniques de préparation comme le laser de structuration et le jet d’eau à ultra haute pression à comparer à d’autres procédés conventionnels tels que le brossage et le sablage. Ces nouvelles alternatives vont permettre alors de mieux comprendre l’influence du décapage et de la rugosité de surface avant la mise en peinture.Enfin, les différents résultats obtenus ont été alors spécifiquement analysés pour permettre la compréhension des phénomènes ou mécanismes d’adhésion se produisant à l’interface du couple époxy/substrat, d’un point de vue mécanique et physico-chimique. Divers moyens d’analyses ont alors pu être mis en œuvre pour caractériser les surfaces d’un point de vue morphologique (ratio de surface) et chimique (spectroscopies Raman et photoélectronique à rayons X (XPS)) pour évaluer la tenue interfaciale (test de traction adhérence)Organic coatings applied on the surface of cast iron pipes ensure very good chemical and anti-corrosion protection against aggressive effluents. To improve adherence between coating (epoxy) and substrate, a surface preparation is required. Among conventional processes shot blasting has emerged as the most efficient and cheapest solution for ensuring stripping while generating adapted roughness. However, as it may enhance both mechanical anchorage and chemical bonding a better understanding of these phenomena should be developed. Besides new eco-friendly alternatives were investigated.Indeed, new techniques were evaluated, i.e. laser structuring and an ultra-high pressure water jet whose major benefits are understanding the effect of ablation and surface roughness prior to applying a coating. Moreover, two other conventional processes (sand blasting and brushing) were introduced to obtain a various roughness.Results obtained were then analyzed to further understand bonding mechanisms at the interface.Several processes were then implemented to evaluate the surface morphology as well as the surface chemistry (spectroscopy Raman and XPS) correlated to the adhesion mechanisms
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de, Farias Lima Flávia. "Oilfield produced water treatment with electrocoagulation." Doctoral thesis, 2018. https://tud.qucosa.de/id/qucosa%3A35508.
Full textAbstract:
Produced water is the largest waste product by volume in the oil industry and its treatment in onshore or offshore fields poses bigger and different challenges than what water engineers are used to encounter. Process to achieve reuse quality of this water is very expensive with many technical hurdles to overcome making the optimization of the treatment steps necessary.
Electrocoagulation (EC) generates coagulants in-situ responsible for destabilizing oil droplets, suspended particles, and common pollutant in produced water. Furthermore, EC is a very efficient technology compared with traditional primary treatments used in the oil & gas industry and has several advantages such as: no hazardous chemical handling (which diminishes the risk of accident and logistic costs), high efficiency potential concerning boron removal, potential small footprint and less sludge generation.
In this research, the treatment of produced water using EC was investigated in a practical manner for the oilfield to aim for a cleaner effluent for further processing and help to achieve a reuse quality. For this, an EC cell was designed using different parameters normally used in the literature to fit this scenario. After preliminary tests, the treatment time was set to 3 seconds. Response surface method (RSM) was employed to optimize the operating conditions for TOC removal on a broad quality of synthetic produced water while varying: salinity, initial oil concentration and initial pH. TOC was chosen to be the main response because of its importance in legislation and sensibility on the method.
Furthermore, turbidity removal, change of pH value after EC in water with lack of buffer capacity, aluminum concentration and preliminary tests involving boron removal and influence of hydrogen carbonate were also studied. Real produced water was treated with EC to assess the optimum conditions obtained by the RSM showing the results were closely related. Finally, an estimation of volume required and operating cost for EC in the different types of produced water was made to assess how realistic it is for onshore and offshore applications.:ERKLÄRUNG DES PROMOVENDEN I
ACKNOLEDGEMENT III
ABSTRACT V
TABLE OF CONTENT VII
LIST OF FIGURES IX
LIST OF TABLES X
LIST OF EQUATIONS XII
ABBREVIATIONS XIV
1. INTRODUCTION 1
2. PRODUCED WATER 6
2.1 Characterization of Oilfield Produced Water 6
2.2 Produced Water Management 10
2.2.1 Discharge and Regulations 10
2.2.2 Efforts on Reuse 11
2.2.3 Cost 14
3. PRODUCED WATER TREATMENT 17
3.1 Most Common Primary Treatment 17
3.1.1 Hydrocyclones 17
3.1.2 Flotation unit 18
3.2 Further Water Treatment Technologies 19
3.2.1 Membrane Process 19
3.2.1.1 Microfiltration 19
3.2.1.2 Ultrafiltration 21
3.2.1.3 Nanofiltration 23
3.2.1.4 Reverse Osmosis 24
3.2.1.5 Forward osmosis 24
3.2.2 Electrodialysis 25
3.2.3 Biological treatment 28
3.2.3.1 Aerobic and anaerobic process 28
3.2.3.2 Combining membrane and bio-reactor 29
3.2.4 Oxidative process 30
3.2.4.1 Oxidation process 30
3.2.4.2 Anodic oxidation 32
3.2.5 Thermal technology 34
3.2.5.1 Evaporation 34
3.2.5.2 Eutectic freeze crystallization 35
3.2.6 Adsorption and ion-exchange 36
3.3 Electrocoagulation 39
3.3.1 Colloidal Stability Theory 39
3.3.2 Theory of Electrocoagulation 40
3.3.3 Mechanism of Abatement of Impurities 44
3.3.4 Operational parameters and efficiency 49
4. MATERIALS AND METHODS 51
4.1 Analytical Techniques and Synthetic Solutions 51
4.1.1 Analytical Techniques 51
4.1.2 Synthetic Produced Water 51
4.2 Design of Experiment and Models 54
4.3 Experimental Protocol for EC 56 4
.4 Development of the new Electrocoagulation cell 57
4.5 Real Produced water 58
5. RESULTS AND DISCUSSION 59
5.1 Designing EC Cell Process 59
5.1.1 Computational Fluid Dynamics for EC manufacturing 59
5.2 Preliminary Experiments 61
5.2.1 TOC Removal and Residence Time Determination 61
5.2.2 Aluminum Concentration 64
5.3 Models Quality and Range of Validity 66
5.3.1 TOC Removal 66
5.3.2 Turbidity Removal 69
5.3.3 Final pH value 71
5.3.4 Ionic Strength and Interpolation for Different Salinities 73
5.3.5 Partial Conclusions 76
5.4 Evolution of the Final pH Value 78
5.5 Operation Region for Effective Treatment of Produced Water with EC 80
5.5.1 Produced Water with Low Salinity 80
Organic Compounds Removal 80
Turbidity Removal 83
5.5.2 Produced Water with Medium Salinity 84 Organic Compounds Removal 84
Turbidity Removal 86
5.5.3 Produced Water with High Salinity 87
Organic Compounds Removal 87
5.6 Influence of Hydrogen Carbonate 90
5.7 Real Produced water 91
5.8 Boron Removal 93
5.9 Estimation of the Size for EC in Full scale 94
5.10 Produced Water with Very Low Salinity and EC 95
5.11 Estimation of Operation Cost 96
6. CONCLUSION AND RECOMMENDATIONS 98
6.1 Conclusion 98
6.2 Recommendations for Future Work 101
Scale up on EC for upstream 101
Further processing and reuse 101
Online optimization for EC 101
Recommendations for any research related to upstream produced water 101
BIBLIOGRAPHY 102
APPENDIX A 117
APPENDIX B 120
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Mashamaite, Aubrey Nare. "Electroflocculation of river water using iron and aluminium electrodes." Thesis, 2008. http://hdl.handle.net/10352/269.
Full textAbstract:
M. Tech. (Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology.A novel technology in the treatment of river water, which involves an electrochemical treatment technique to produce domestic or drinking water is being investigated using aluminium and iron electrodes in an electrochemical circuit. Coagulation and flocculation are traditional methods for the treatment of polluted water. Electrocoagulation presents a robust novel and innovative alternative in which a sacrificial metal anode treats water electrochemically. This has the major advantage of providing mainly active cations required for coagulation and flocculation, without increasing the salinity of the water. Electrocoagulation is a complex process with a multitude of mechanisms operating synergistically to remove pollutants from the water. A wide variety of opinions exist in the literature for key mechanisms. A lack of a systematic approach has resulted in a myriad of designs for electrocoagulation reactors without due consideration of the complexity of the system. A systematic, holistic approach is required to understand electrocoagulation and its controlling parameters. An electrocoagulation-flotation process has been developed for water treatment. This involved an electrolytic reactor with aluminium and/or iron electrodes. The water to be treated (river water) was subjected to coagulation, by Al(III) and Fe(II) ions dissolved from the electrodes, resulting in floes floating after being captured by hydrogen gas bubbles generated at the cathode surfaces. Apparent current efficiencies for AI and Fe dissolution as aqueous Al(III) and Fe(II) species at pH 6.5 and 7.8 were greater than unity. This was due to additional chemical reactions occurring parallel with electrochemical AI and Fe dissolution: oxygen reduction at anodes and cathodes, and hydrogen evolution at cathodes, resulting in net (i.e. oxidation plus reduction) currents at both anodes and cathodes. Investigation results illustrate the feasibility of ferrous and aluminium ion electrochemical treatment as being a successful method of water treatment. Better results were achieved under conditions of relatively high raw water alkalinity, relatively low raw water turbidity, and when high mixing energy conditions were available.
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HSIEH, CHENG-YUN, and 謝承芸. "Study on the Reaction Mechanisms of Rare Earth Elements and Stable Lead Isotopes along the Waste Water Treatment in Textile Mills." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/8d35gg.
Full textAbstract:
碩士國立中正大學
地球與環境科學研究所
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Rare earth elements (REEs) and lead isotopes can indicate some important chemical environments, such as redox state and sorption process, and indicate the sources of lead, respectively. In this study, both of them were applied on the wastewater from a textile mill in Taiwan for evaluating the chemical environments differences along the wastewater treatment system. The samples were collected from the inflow of wastewater, aeration pool, activated sludge pool, chemical precipitation tank, sedimentation pool and the effluent. Major elements and heavy metals were measured with ICP-OES. REEs and lead isotopes, and other inorganic components of water were measured with ICP-MS. The results of REE analysis demonstrate that strongly adsorption in the active sludge treatment causes HREE enrichment owing to the preferable adsorption of light REEs on the surface of activated sludge due to the smaller hydrated ion radii of light REEs. Moreover, the Ce negative anomaly can be observed, which indicates that the oxidation reactions may become considerable due to the redox increasing. However, the Eu positive anomaly is also observed, which was probably cause by the predominant form of neutral coordination complex (EuOH(CO3)0) in the wastewater. The concentration of lead decreases along the wastewater treatment, which means there is no extra lead sources. Besides, the results of principal component analysis (PCA) show that the behavior of metal ions along the wastewater is highly affected by wastewater treatment, especially the active sludge treatment. Therefore, it is concluded that the wastewater treatment with activated sludge is strongly controlled by adsorption process.
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Li, Wen. "Mechanisms for phosphorus elimination in constructed wetlands: a pilot study for the treatment of agricultural drainage water from dairy farms at the Lower River Murray, South Australia / Li Wen." 2002. http://hdl.handle.net/2440/21868.
Full textAbstract:
Includes list of publications issued during the candidature.Bibliography: leaves 176-197.
iii, ix, 197, [22] leaves : ill., maps ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Phosphorus retention was measured in five pilot-scaled constructed wetlands with different configurations in terms of macrophyte species and substrates in order to evaluate the phosphorus removal efficiency of water plants and substrates in experimental ponds; assess the contribution of macrophytes to phosphorus removal through direct uptake, modification of water chemistry and impacts on the phosphorus adsorption characteristics of substrate; and, contribute to the optimal design and operation of constructed wetlands for the treatment of agricultural drainage water.
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2002?
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Li, Wen. "Mechanisms for phosphorus elimination in constructed wetlands: a pilot study for the treatment of agricultural drainage water from dairy farms at the Lower River Murray, South Australia / Li Wen." Thesis, 2002. http://hdl.handle.net/2440/21868.
Full textAbstract:
Includes list of publications issued during the candidature.Bibliography: leaves 176-197.
iii, ix, 197, [22] leaves : ill., maps ; 30 cm.
Phosphorus retention was measured in five pilot-scaled constructed wetlands with different configurations in terms of macrophyte species and substrates in order to evaluate the phosphorus removal efficiency of water plants and substrates in experimental ponds; assess the contribution of macrophytes to phosphorus removal through direct uptake, modification of water chemistry and impacts on the phosphorus adsorption characteristics of substrate; and, contribute to the optimal design and operation of constructed wetlands for the treatment of agricultural drainage water.
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2002?