Dissertations / Theses on the topic 'Wastewater treatment (including water treatment processes)'

In recent years, endocrine disruption of corticosteroid signaling pathways in wildlife and humans by environmental chemicals have attracted increasing attention. The integrated potential of chemicals in the aquatic environment that disrupt corticosteroid actions have been evaluated using in vitro glucocorticoid receptor (GR) mediated bioassays. Exogenous natural and synthetic corticosteroids (CSs), which are widely used in human and animal therapeutic applications, were demonstrated to be the most important GR agonists, that can potentially cause adverse effects, especially on aquatic organisms. To date, only a few studies have investigated the occurrence and behavior of GR agonists in the aquatic environment and their removal in conventional wastewater treatment plants. Furthermore, there are hardly any data reported on the removal of GR agonists by advanced water and wastewater treatment, especially those synthetic CSs with high potency. To further understand the fate of GR agonists in water and wastewater treatment processes, a sensitive and robust LC-MS/MS method was successfully developed for analyzing a wide range of GR agonists in various environmental waters. The occurrence of GR agonists in surface water and groundwater was monitored along the Lower Santa Cruz River (SCR). Several GR agonists were detected, and a trend of degradation was observed downstream the two WWTP outfalls for both surface water and groundwater. The fate of GR agonists in a local wastewater treatment plant (WWTP) was investigated, and up to 14 GR agonists were detected at different stages. Highly potent synthetic CSs, including clobetasol propionate (CBP), fluticasone propionate (FTP), fluocinolone acetonide (FCA), and triamcinolone acetonide (TCA), were poorly removed in WWTP. Negative removal of some CSs was observed in primary treatment, which may due to the deconjugation of CS conjugates. Removal of GR agonists in secondary effluent during various advanced water treatment processes, including UV, ozonation, MF, RO and chlorination, were studied. UV and RO appeared to be the most efficient treatment process for the attenuation of GR agonists, followed by ozone, while chlorination had little effects on GR agonists in water. Bench-scale experiments were then carried out to investigate the removal of GR agonists by ultraviolet based advanced oxidation processes (UV/AOPs), and powder activated carbon (PAC). UV/chlorine and UV/H2O2 were demonstrated to be effective in removal GR agonists in wastewater, and UV photolysis would be the predominant mechanism in UV/AOP processes. Four types of PACs were tested for removing GR agonists in wastewater effluent, and Cabot HDB carbon was suggested, while Calgon PWA carbon was not recommended due to its low removal efficiency.

Today billions of people live without access to basic sanitation facilities, and thousands die every week due to diseases caused by fecal contamination associated with improper sanitation. It has thus become crucial for decision makers to have access to relevant and sufficient data to implement appropriate solutions to these problems. The Global Water Pathogen Project http://www.waterpathogens.org/ is dedicated to providing an up-to-date source of data on pathogen reduction associated with different sanitation technologies that are important if the world is to achieve the Sustainable Development Goals (SDGs) related to health and sanitation provision. In this research, a subset of the Global Water Pathogen Project (GWPP) data is used to access the reduction of bacteria and viruses across different mechanical and natural sanitation technologies. The order of expected removal for bacteria during wastewater treatment was reported as highest for a membrane bioreactor (4.4 log10), waste stabilization pond (2.3 log10), conventional activated sludge (1.43 log10), anaerobic anoxic oxic activated sludge (1.9 log10), trickling filter (1.16 log10), and upflow anaerobic sludge blanket reactor (1.2 log10).

Furthermore, the order of expected removal for viruses was reported as highest for a membrane bioreactor (3.3 log10), conventional activated sludge (1.84 log10), anaerobic anoxic oxic activated sludge (1.67 log10), waste stabilization pond (1 log10), upflow anaerobic sludge blanket reactor (0.3 log10) and trickling filter (0.29 log10). It was found that hydraulic retention time (HRT) had a statistically significant relation to the reduction of bacteria in an anaerobic, anoxic oxic treatment system. Similarly, a significant relation was found between the number of waste stabilization ponds in series and the expected reduction of bacteria. HRT was also found to be a significant factor in virus reduction in waste stabilization ponds. Additionally, it was observed that waste stabilization ponds, trickling filters, and UASB reactors could obtain a greater reduction in bacteria (5–7 log10) when combined with additional treatment (e.g., chemical disinfection or use of maturation ponds). Also, mechanized systems, such as activated sludge systems and membrane bioreactors, obtained a greater reduction (2–3 log10) of viruses when compared to a natural system. It was concluded that the selection of the best suitable technology for pathogen reduction depends on environmental, design, and operational factors as well as considering the performance of specific wastewater treatment systems individually as well as when combined with other treatment technologies that may provide added removal of microbial constituents.

Water treatment plant (WTP) residual discharge is considered a pollutant and requires treatment to prevent negative impacts when released to the environment. As regulatory requirement becomes increasingly strict, WTPs are required to find suitable methods for the treatment of sludge residuals. Wastewater treatment plants(WWTP) provide existing treatment methods to remove contaminants from WTP residuals. A case study on the Carbondale Water Treatment Plant (CWTP) and receiving Carbondale Southeast Waste Water Treatment Plant (SEWWTP) provided an opportunity to quantify potential negative impacts for the discharge of residual alum sludge to a biologic sludge digestion plant. The first part of the study focused on quantifying changes to the SEWWTP loading conditions from the addition of metal salt coagulant water treatment residuals discharged by the CWTP. Historic sludge quantities and treatment methodologies for both the CWTP and SEWWTP were used to predict loading conditions and residual concentrations at the SEWWTP. Ammonia, BOD, pH, and TSS concentrations from the CWTP were not identified to significantly impact the existing concentrations at the SEWWTP. Metals concentrations from the CWTP were also found to fall within WWTP regulatory quantities. The second part of the study evaluated potential impacts to beneficial bacteria populations in the SEWWTP oxidation ditch from the receipt of CWTP alum residuals. Studies of residual alum sludge impacts to beneficial bacterial populations are rare, and often do not translate from one treatment plants processes to the next. The SEWWTP employs a multi-ring oxidation ditch with an anoxic outer ring and aerobic middle and inner rings. Biologic Activity Reaction Tests (BART) were used to isolate beneficial bacteria species typically present in oxidation ditches including heterotrophic aerobic bacteria, denitrifying bacteria, and nitrifying bacteria. Heterotrophic aerobic bacteria and denitrifying bacteria are the predominant beneficial bacteria species in the outer ring, while nitrifying bacteria and heterotrophic aerobic bacteria dominate the aerobic inner rings. Heterotrophic aerobic bacteria and denitrifying bacteria populations identified in the outer ring of the oxidation ditch did not demonstrate any population impacts from the receipt of residual alum sludge. In addition, nitrifying bacteria populations and heterotrophic aerobic bacteria population demonstrated no impacts from the introduction of CWTP residual alum waste to the aerobic inner ring of the oxidation ditch. Overall, the study demonstrated the treatment of residual alum sludge from a WTP is possible through the existing biological processes at a WWTP.

Today billions of people live without access to basic sanitation facilities, and thousands die every week due to diseases caused by fecal contamination associated with improper sanitation. It has thus become crucial for decision makers to have access to relevant and sufficient data to implement appropriate solutions to these problems. The Global Water Pathogen Project http://www.waterpathogens.org/ is dedicated to providing an up-to-date source of data on pathogen reduction associated with different sanitation technologies that are important if the world is to achieve the Sustainable Development Goals (SDGs) related to health and sanitation provision. In this research, a subset of the Global Water Pathogen Project (GWPP) data is used to access the reduction of bacteria and viruses across different mechanical and natural sanitation technologies. The order of expected removal for bacteria during wastewater treatment was reported as highest for a membrane bioreactor (4.4 log10), waste stabilization pond (2.3 log10), conventional activated sludge (1.43 log10), anaerobic anoxic oxic activated sludge (1.9 log10), trickling filter (1.16 log10), and upflow anaerobic sludge blanket reactor (1.2 log10). Furthermore, the order of expected removal for viruses was reported as highest for a membrane bioreactor (3.3 log10), conventional activated sludge (1.84 log10), anaerobic anoxic oxic activated sludge (1.67 log10), waste stabilization pond (1 log10), upflow anaerobic sludge blanket reactor (0.3 log10) and trickling filter (0.29 log10). It was found that hydraulic retention time (HRT) had a statistically significant relation to the reduction of bacteria in an anaerobic, anoxic oxic treatment system. Similarly, a significant relation was found between the number of waste stabilization ponds in series and the expected reduction of bacteria. HRT was also found to be a significant factor in virus reduction in waste stabilization ponds. Additionally, it was observed that waste stabilization ponds, trickling filters, and UASB reactors could obtain a greater reduction in bacteria (5-7 log10) when combined with additional treatment (e.g., chemical disinfection or use of maturation ponds). Also, mechanized systems, such as activated sludge systems and membrane bioreactors, obtained a greater reduction (2-3 log10) of viruses when compared to a natural system. It was concluded that the selection of the best suitable technology for pathogen reduction depends on environmental, design, and operational factors as well as considering the performance of specific wastewater treatment systems individually as well as when combined with other treatment technologies that may provide added removal of microbial constituents.

This research effort involved the application of indirect- and direct-contact, freeze-thaw conditioning techniques for improving the dewatering characteristics of both wastewater and water treatment sludges. Sludges tested included waste activated sludge, primary sewage sludge, waste activated/primary sewage sludge mixtures and alum sludge. The direct-freeze methods examined were the use of a secondary refrigerant (butane) evaporated in the sludge and the use of gas hydrate or clathrate formation by addition of Freon 12 under appropriate temperature and pressure conditions. Sludges were also frozen solid using indirect freezing methods, thawed and tested for comparative purposes. Particle size distribution and floc density measurements were used to determine changes in particle characteristics; specific resistance values and dewatered dry solids concentration were used to assess dewatering characteristics. Results of direct- and indirect-contact, freeze-thaw conditioning were compared to the effects of polymer conditioning. The results indicated that direct-freeze methods do not appear technically or economically competitive with currently accepted conditioning methods. The superior results obtained with the indirect-contact, freeze-thaw process when compared to the direct-contact processes suggested that the extent and rate of freezing may greatly influence the particle characteristics of the conditioned sludge, and thus its dewatering characteristics.
Ph. D.

In the 21st Century, water is already a limited and valuable resource, in particular the limited availability of fresh water sources. The projected increase in global population from 6 billion people in 2010 to 9 billion in 2050 will only increase the need for additional water sources to be identified and used. This situation is common in many countries and is frequently exacerbated by drought conditions. Water management planning requires both the efficient use of water sources and, increasingly, the re-use of domestic and industrial wastewaters. A large body of published research spanning several decades is available, and this research study looks specifically at ways of improving the operation of wastewater treatment processes.Process fault diagnosis is a major challenge for the chemical and process industries, and is also important for wastewater treatment processes. Significant economic and environmental losses can be attributed to inappropriate Abnormal Event Management (AEM) in a chemical/processing operation, and this has been the focus of many researchers. Many researchers are now focusing on the application of several fault diagnosis techniques simultaneously in order to improve and overcome the limitations experienced by the individual techniques. This approach requires resolution of the conflicts ascribed to the individual methods, and incurs additional costs and resources when employing more than one technique. The research study presented in this thesis details a new method of using the available techniques. The proposal is to use different techniques in different roles within the diagnostic approach based upon their inherent individual strengths. The techniques that are excellent for the detection of a fault should be employed in the fault detection, and those best applied to diagnosis are used in the diagnosis section of a diagnostic system.Two different techniques are used here, namely a mathematical model and data mining are used for detection and diagnosis respectively. A mathematical model is used which is based upon the principal of analytical redundancy in order to establish the presence of a fault in a process (the fault detection), and data mining is used to produce production rules derived from the historical data for the diagnosis. A dataset from an industrial wastewater treatment facility is used in this study.A diagnostic algorithm has been developed that employs the techniques identified above. An application in Java was constructed which allows the algorithm to be applied, eventually producing an intelligent modelling agent. Thus the focus of this research work was to develop an intelligent dynamic modelling system (using components such as mathematical model, data mining, diagnostic algorithm, and the dataset) for simulation of, and diagnosis of faults in, a wastewater treatment process where different techniques will be assigned different roles in the diagnostic system.Results presented in Chapter 5 (section 5.5) show that the application of this combined technique yields better results for detection and diagnosis of faults in a process. Furthermore, the dynamic update of the set value for any process variable (presented in Chapter 5, section 5.2.1) makes possible the detection of any process disturbance for the algorithm, thereby mitigating the issue of false alarms. The successful embedding of both a detection and a diagnostic technique in a single algorithm is a key achievement of this work, thus reducing the time taken to detect and diagnose a fault. In addition, the implementation of the algorithm in the purposebuilt software platform proved its practical application and potential to be used in the chemical and processing industries.

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

Els Processos Avançats d'Oxidació (PAOs) són tècniques de degradació química basades en la producció in situ del potent reactiu radical hidroxil. L'acoblament entre PAOs i sistemes biològics pel tractament d'aigua contaminada amb compostos biorecalcitrants és una alternativa útil als mètodes de gestió convencionals. El principal benefici d'aquests tractaments acoblats és la minimització del pretractament químic fins a generar intermedis més biodegradables. Subseqüentment, un tractament convencional d'aigües residuals, basat en la activitat de microorganismes, es pot utilitzar per eliminar completament la matèria orgànica del medi.
Aquest tesi desenvolupa una estratègia d'acoblament entre sistemes químics i biològics per tractar herbicides específics com exemple de contaminants tòxics i no biodegradables produïts per l'home.
Advanced Oxidation Processes (AOPs) are chemical degradation techniques based on the in situ production of the powerful reactive hydroxyl radical. The coupling between AOPs and biological systems for the treatment of water polluted with biorecalcitrant compounds is a useful alternative to conventional management methods. The main benefit of these coupled treatments is the minimization of the chemical pretreatment to generate more biodegradable by-products. Subsequently, a conventional wastewater treatment, based on the activity of microorganisms, can be used to completely remove organic matter from solution.
This thesis deals with the development of a chemical and biological coupling strategy to treat some specific herbicides as examples of toxic and non biodegradable anthropogenic pollutants.

Due to their potential health impact on human beings and ecosystems, persistent trace organic compounds (TOrCs) have aroused concern from both the public and professionals. In particular, the discharge of pharmaceuticals, endocrine disrupters, disinfection byproducts and other TOrCs from wastewater treatment plants into the environment is an area of extensive current research. This work studies the fate and treatments of TOrCs, with emphases on advanced oxidation processes (AOPs). This work presents predicted removal efficiencies of a variety of engineered and natural processes for 55 frequently encountered TOrCs in treated wastewater, based on previously reported data and using existing predictive models. Correlations between physicochemical and biological properties of TOrCs and treatment performance were explored. Removal of TOrCs in all processes investigated in this study was found to be sensitive to matrix effects. Heuristic guidelines for selection of sequenced treatment processes for TOrCs management were established. A field reconnaissance of natural process of TOrCs was conducted by analyzing the occurrence and fate of a suite of TOrCs, as well as estrogenic activity in water and sediments in the Santa Cruz River, an effluent-dependent stream in Tucson, Arizona. Some TOrCs, including contributors to estrogenic activity, were rapidly attenuated with distance of travel in the river. TOrCs that have low biodegradability and low octanolwater partitioning coefficients were less removed. Results of independent experiments indicated potential indirect photodegradation of estrogenic compound by reactive species generated from photolysis of effluent organic matter. Utilizing advanced oxidation processes (AOPs) as tertiary water and wastewater treatment is an option to prevent discharge of TOrCs into the environment. Compared to conventional AOPs, the ability of generating hydroxyl radicals (•OH) without additional doses of hydrogen peroxide (H2O2) or ozone makes ultraviolet (UV) photolysis of ferric hydroxo complexes a novel AOP, especially in acidic environments. A Fe(III)/UV254 kinetic model, which combines Fenton-like mechanism, and photolyses of Fe3+, FeOH2+ and H2O2 was proposed and experimentally validated to predict Fenton-like and H2O2 direct UV254 photolysis scenarios, individually. Nevertheless, the model underestimated the ferrous ion development during Fe(III)/UV254 photolysis, perhaps due to the overprediction of the oxidation of Fe2+ by •OH. The UV/H2O2 AOP was also studied in this work. A predictive kinetic model was developed to evaluate process efficiency of oxidation of p-cresol by UV/H2O2 photolysis based on a complete reaction mechanism, including reactions of intermediates with •OH. Results of this study highlight the significance of consideration of radical scavenging effects by the byproducts from oxidation of organic matter in model prediction performance.

The reuse of treated wastewater in irrigation is fundamental in the management of water resources. The aims of this study were the performance assessment of NF/RO processes for reclamation of MBR-treated wastewater, the concentrate recovery and permeate quality assessment for irrigation. Wastewater processed by MBRs in “ITOB” wastewater treatment plant, located in Izmir, Turkey, was used in NF/RO filtration tests in a pilot-scale plant containing BW30 (RO), NF90 (NF) and NF270 (NF) membranes. Experiments were conducted using single membrane modules (in batch mode and concentrate recirculation flow configuration) and with two membranes connected in series. MBR effluent and NF/RO permeate quality were compared with the standard values found in guidelines (FAO, WHO and USEPA) and regulations (Turkish and Italian regulations). Permeate flux was higher for NF270 membrane while the lowest was for BW30 membrane. Salt rejections of BW30 membrane were significantly higher than those obtained with NF270 membrane, while with NF90 membrane, permeate fluxes were slightly lower than those of NF270 membrane with salt rejections close to those of an RO membrane. With concentrate recirculation flow configuration, the concentrate recovery was increased by increasing the concentrate recirculation. However, the operation has to be stopped when the feed solution concentration can compromise the performances of the system and shorten the membrane life. In the system with two membranes in series, high water recovery was achieved. BW30-NF270 system showed higher permeate flux, however, its quality is comparable to this one of NF270 membranes. NF90 and BW30 permeates meet the standards for irrigation, and negative effects on soil permeability can be minimized by mixing them with low amounts of MBR effluent. NF270 permeates contain excessive amount of nitrogen, and NaCl. MBR effluent is not suitable for irrigation, due to excessive salinity, NaCl, TDS and nitrogen content.

Water and sanitation (WatSan) development projects impact both natural systems and societal structures where they are placed. A complex process of development, including inter-governmental policies, aid agencies, personal relationships, and community politics enhance and constrain the efficacy of these projects. This study presents the many ways in which the WatSan development process has unintended and unexpected returns for certain community groups. Using a political ecology framework, I look at power structures, perceived and projected environmental impacts, multiple stakeholders, and individual discourses to critique how the right to water and sanitation is implemented in a specific community context. This project advances anthropological thought by showing a praxis-based study that links theory, on-the-ground, ethnographic experience, policy recommendations, and theoretical injections which relate to a variety of audiences, both within and outside of the academy. The project is conducted in two main field locations--La Paz and Sapecho, Bolivia. I employ a mixed-method approach, including interviews with development professionals and community members, a survey of water and sanitation users, focus groups with particularly impacted groups (e.g. water committees, students, and women), and various mapping techniques (GPS mapping, community-led) to address the space and place within which this project was realized. I give specific focus to sewage collection and wastewater treatment, two elements of the WatSan system that are distinctive in this rural developing-country context. WatSan development is not just infrastructure placement. It is a full process, a relationship. It comprises individual conversations, days of work, salaries, payment schedules, labor, expertise, and ongoing management practices. Individual perceptions of infrastructure efficacy, personal benefit, and best practices (both culturally and technologically) impact the long-term effectiveness of a project. Major tensions arise post-implementation: between community and aid agency, conservation and use, labor and upkeep, and sanitation and potable water. There are multiple influences and positions subsumed in this process. The study's political ecology approach, combined with foci on human rights, critical development, and water and culture, provides critical insights into the relationship between social and resource-based (water infrastructure) change. It looks at the ways in which the benefits and risks of a WatSan system are stratified, gendered, and power-laden. It further looks at the potential positive and negative outcomes of the system--all with an enviro-social focus. I look at how social and ecological relationships are tethered together (mutually constituted), how they are influenced by several levels of governance and policy. The experience of Sapecho shows how changes to WatSan environments can provide new water and sanitation access but in some cases, further engrain and exacerbate social inequalities. Provision of fresh water, sewage collection, and wastewater treatment infrastructure is not value-free--but it is necessary. This work tries to answer one small part of the question of how the right to water and sanitation can be best implemented in real-world situations.

District heating has a long standing tradition in Sweden and today it is the most common way of producing and transporting heat. A District heating system (DH system) is divided into three parts: a production facility, distribution network (DH network) and one more heat stations. The heat produced in the facilities is distributed to the customers via a heat transfer medium, usually water (DH water), in piping networks that make up the DH network. The heat is transferred to the customers via the heat exchanger at which point they can use it as heated tap water or for heating purposes. The DH networks are often constructed in steel as it is cheap and a relatively resistant material. However it has the disadvantages of corrosion and expansions when it is exposed high temperatures which lead to damages in the DH network resulting in loss of the DH water, this is an unavoidable occurrence in any DH network. This results in addition of pollutants by leakages into the DH network or with the water that is used to compensate for the losses. The pollutants cause further corrosion, leading to metal contamination, and more damages on the DH network meaning there is a continuous degradation. Therefore various treatments are used to clean and ascertain an acceptable chemical environment in the DH systems. These treatments are effective but not at a level which is required so many chemicals are used to enhance the treatment of the water. Some of these are known to be toxic to humans and water ecosystems. As leakages are abundant and often end up in the WWTPs of the concerned municipality, which often have troubles with disturbances of the biological treatment, it was decided that an assessment of the toxic effects that DH water pose on activated sludge was to be investigated. This was done by testing water from two DH networks, Växjö and Kalmar, on the same activated sludge obtained from Tegelviken WWTP in Kalmar. A respirometric bioassay approach established by the Organization for Economic Co-operation and Development (OECD), OECD standard 209; OECD Guidelines for the Testing of Chemicals was used with changes made to exposure and measuring time as this decrease the risk of misinterpretation of the results. A dilution series using different concentrations (6.25%, 25% and 100%) of DH water was tested and compered to a blank control samples containing only activated sludge. Assessment of toxicity on total oxidation, oxidation carbon and oxidation of nitrogen was made. To get some idea of what might cause toxic effect samples of the waters was sent to outside laboratories for analyses of metals. The result from the bioassay and metal analysis was used to formulate risk factors associated with a DH water spill and exposure to WWTPs. It was found that both DH waters have a significant inhibition on nitrification in WWTPs. The DH water from Kalmar exhibited similar toxicity dynamics, roughly 20% inhibition, despite large differences in concentration. The DH water from Växjö showed a negative correlation between an increase in concentration of DH water and toxicity, 74% for the lowest concentration and 11% for the highest. The metal analysis concluded that there was no abundance of metal contamination which led to the inference that toxicity is probably caused by the chemicals used for treatment. This poses a great risk for the Baltic Ocean as many WWTPs release their treated water directly into water courses with a short detention time before reaching the sea.

Abstract Industrial wastewaters are complex waters, which can contain a large variety of compounds such as heavy metals and salts as well as nutrients, e.g. nitrogen compounds and phosphorous. Prevention of wastewater formation is not always possible and therefore new more efficient water treatment techniques are needed. Legislation also supports the use of more efficient water treatment techniques, which can lead to better purification results and the recovery of valuable compounds from wastewaters. One technique, which has been of interest, is membrane technology. Membrane technology can separate heavy metals, salts and nutrients effectively, also at low concentrations, which is not always possible with conventional water treatment methods. The main disadvantage of membrane technologies is membrane fouling, which reduces the membrane permeate flux and separation efficiency. In this thesis membrane techniques were combined into hybrid processes to increase the efficiency of water treatment to reduce fouling and to widen the application areas of membrane technologies, as well as to increase the awareness of the benefits gained when using hybrid membrane processes in wastewater treatment. Three different hybrid membrane processes were applied. Catalytically active nanofiltration membranes were used to purify real mine wastewaters from harmful compounds, including sulphate. A catalytic layer reduced the membrane fouling tendency. Micellar-enhanced ultrafiltration was applied successfully to the separation of heavy metals from phosphorous-rich wastewater of a fertilizer company to achieve selective separation. In addition, reverse osmosis and membrane distillation were applied to the concentration of heavy metals, a metalloid and nitrogen compounds containing synthetic wastewater efficiently. High volume concentration factor was achieved with the RO-MD process. In this thesis high heavy metal, metalloid, and salt removal efficiencies were achieved with all hybrid membrane techniques. Hybrid membrane techniques were also categorized based on their properties. The study provides new knowledge on hybrid membrane techniques in the removal of inorganic compounds from industrial waters
Tiivistelmä Teollisuuden jätevedet voivat sisältää kohonneita haitta-ainepitoisuuksia, kuten raskasmetalleja ja suoloja. Teollisuuden jätevedet voivat sisältää myös ravinteita, esimerkiksi typen yhdisteitä ja fosforia. Jätevesien syntymistä ei aina voida ennaltaehkäistä, ja siksi uusille entistä tehokkaammille vedenkäsittelymenetelmille on tarvetta. Lisäksi myös lainsäädäntö vaatii entistä tehokkaampaa vesien puhdistusta, mikä osaltaan edistää entistä tehokkaampien puhdistustekniikoiden kehitystä sekä erotettujen aineiden talteenottoa. Yksi aktiivisen tutkimuksen kohteena oleva vesienkäsittelyssä käytetty menetelmä on kalvoerotustekniikka. Kalvoerotustekniikoilla voidaan erottaa tehokkaasti raskasmetalli-ioneja, sulfaattia ja ravinteita, kuten typpiyhdisteitä teollisuuden jätevesistä myös alhaisissa pitoisuuksissa, missä yleisesti käytettävät menetelmät voivat olla tehottomia. Yksi kalvoerotusmenetelmien ongelma on kalvojen likaantuminen, mikä alentaa kalvojen erotustehokkuutta ja vähentää tuottavuutta. Tässä tutkimuksessa kalvojen likaantumistaipumista on vähennetty yhdistämällä kalvoerotustekniikoita muihin erotusmenetelmiin hybriditekniikoiksi. Tässä työssä on tutkittu kolmea eri hybridimenetelmää. Sinkkioksidilla pinnoitettuja nanosuodatuskalvoja tutkittiin ja verrattiin kaupallisiin nanosuodatuskalvoihin kaivosteollisuuden vesien puhdistuksessa mm. sulfaatista. Katalyyttipinnoite muutti kalvoja vähemmän likaantuviksi, ja näin menetelmän tehokkuus parani. Miselliavusteisella ultrasuodatuksella erotettiin fosforipitoisesta lannoitetehtaan jätevedestä raskasmetalleja selektiivisesti, ja näin mahdollistettiin fosforin uudelleenkäyttö. Kolmannessa tutkimuskohteessa konsentroitiin kalvotislauksen ja käänteisosmoosin yhdistelmällä raskasmetalli- ja typpiyhdisteitä sisältävää synteettistä jätevettä pieneen tilavuuteen. Työssä saavutettiin korkeita raskasmetallien ja suolojen erotustehokkuuksia kaikilla käytetyillä tekniikoilla. Työssä arvioitiin myös yhteenvetona erilaisten hybridimembraanitekniikoiden eroja ja ominaisuuksia ja tekniikoita jaoteltiin menetelmien ominaisuuksien mukaan. Työ antoi uutta tietoa hybridimembraanitekniikoista epäorgaanisten aineiden erotuksessa teollisuuden vesistä

Les procédés électrochimiques d'oxydation avancée constituent une technologie efficace pour traiter les produits pharmaceutiques car ils permettent la formation d'oxydants puissants tels que les radicaux hydroxyles capables d'éliminer presque tout type de contaminants organiques grâce à leur très haut pouvoir oxydant. Parmi eux, l’électro-Fenton et l’oxydation anodique sont des méthodes respectueuses de l'environnement car ils n'utilisent aucun réactif chimique (oxydation anodique) ou uniquement l'oxygène de l'air et des ions fer en tant que catalyseur (électro-Fenton).Dans cette thèse, quatre produits pharmaceutiques appartenant à des familles différentes ont été sélectionnés en fonction de leur toxicité et de leur présence dans les eaux de l'environnement. Leur élimination de l'eau a été effectuée par électro-Fenton. Les objectifs de ce travail étaient de déterminer (i) les meilleures conditions opératoires à l’échelle du laboratoire (courant et concentration du catalyseur), (ii) la cinétique de dégradation et de minéralisation et enfin (iii) de proposer une voie de minéralisation basée sur des intermédiaires aromatiques, des acides carboxyliques et des ions libérés dans la solution.Comme ces traitements ont été appliqués avec succès, un réacteur pilote composé alternativement d'anodes en BDD et de cathodes en feutre de carbone, doté d’un système d'aération et fonctionnant en mode continu a été construit pour évaluer la faisabilité d’un changement d’échelle et se diriger vers une pré-industrialisation du procédé. Différentes configurations d'électrodes ont été testées. Le débit et le courant se sont avérés être plus influents sur le taux de minéralisation et sur la consommation d'énergie, respectivement. Pour mieux comprendre le rôle du débit et des configurations, une étude hydrodynamique a été réalisée. Le modèle hydrodynamique a été associé à un modèle cinétique de minéralisation afin d'obtenir un modèle permettant de prédire le pourcentage de minéralisation à différentes positions à l'intérieur du réacteur en régime permanent. Ainsi, ce modèle peut aider à optimiser les conditions opératoires et à dimensionner les futurs réacteurs en fonction de l’objectif de minéralisation du traitement (taux de minéralisation élevé, traitement combiné, flux élevé,…).Afin de réduire les coûts opératoires, la combinaison d’un procédé électrochimique et d’un traitement biologique a ensuite été étudiée. Afin d’obtenir un traitement combiné efficace, il a été constaté que le traitement électrochimique devait (i) dégrader l'hydrochlorothiazide (ii) réduire de manière significative la concentration de ses intermédiaires aromatiques car ils inhibent de manière significative l'activité bactérienne, (iii) favoriser la formation de molécules biodégradables telles que les acides carboxyliques. La biodégradation de quatre acides carboxyliques formés lors du traitement par électro-Fenton de l'hydrochlorothiazide a également été étudiée. Il a été démontré qu'ils étaient dégradés de manière séquentielle avec différentes phases de latence et cinétiques de dégradation. Ainsi, pour les minéraliser, un réacteur de type «piston» est recommandé. La combinaison de traitement a ensuite été appliquée à un traitement électrochimique effectué à faible courant avec une anode en BDD et une anode en Platine. Un degré de minéralisation de 38 et 50% a été obtenu par le traitement biologique permettant d'atteindre un taux de minéralisation global de 66 et 85% avec les anodes en BDD et Platine respectivement. Ainsi, cette combinaison de traitement a été un succès, un changement d’échelle du procédé peut alors être envisagé
Electrochemical advanced oxidation processes (EAOPs) constitute an efficient technology to treat the pharmaceuticals as they allow the formation of strong oxidants such as hydroxyl radicals able to remove nearly any type of organic contaminants thanks to their very high oxidation power. Among them the electro-Fenton and anodic oxidation processes are environmentally friendly methods as they use no chemical reagent (anodic oxidation) or only oxygen of air and iron ions as a catalyst (electro-Fenton).In this thesis, four pharmaceuticals from different families and structures were selected based on their toxicity and their occurrence in environmental waters and their removal from water was performed by EAOPs. The objectives of this work were to determine the best operating conditions at lab scale (current and catalyst concentration), investigate the kinetic of degradation and mineralization and finally propose a mineralization pathway based on aromatic intermediates, carboxylic acids and ions released to the solution.As these treatments were successfully applied, a lab scale pilot reactor composed alternately of BDD anodes and carbon felt cathodes with a bottom aeration system and working in the continuous mode was built to scale-up these processes in order to pre-industrialize them. Different configurations of electrodes were tested. The flow rate and the current were found to be more influent on the mineralization rate and on the energy consumption, respectively. To deeper understand the role of the flow rate and the configurations a hydrodynamic study was performed. The hydrodynamic results were gathered with a kinetic model for the mineralization to obtain a model predicting the percentage of mineralization at different position inside the reactor during the steady state. Thus, this model can help to optimize the operating conditions and to size future reactors depending on the mineralization objective of the treatment (high mineralization rate, combined treatment, high flow, …).To reduce operating cost, the combination of an electrochemical process and a biological treatment was then investigated. In this frame, it was found that electrochemical treatment can (i) degrade the hydrochlorothiazide (ii) reduce significantly the concentration of its aromatic intermediates as they were shown to significantly inhibit the bacterial activity, (iii) promote the formation of biodegradable molecules such as carboxylic acids. The biodegradation of four carboxylic acids formed during the electro-Fenton treatment of the hydrochlorothiazide at lab scale was also studied. It was demonstrated that they were sequentially degraded with different lag phases and kinetics of degradation. Thus to mineralize them, a “plug flow” type reactor is recommended. The combination of treatment was then applied with an electrochemical treatment performed at low current with a BDD anode and a Platine anode. A mineralization degree of 38% and 50% were obtained by the biological treatment enabling to globally reach a mineralization rate of 66% and 85% with the BDD and the Platine anodes respectively. Thus this combined treatment was successful and open the way for the scale-up of these processes

This thesis deals with Advanced oxidation processes (AOP) and its aplication for textile wastewaters treatment and reuse. AOP is a modern technology which currently recieves increased attention due to it´s high efficiency in removing resistant and hardly-degradable pollution. Thesis consists of search and practical part. Search part is created by three chapters. First chapter describe briefly wastewater reuse. The second chapter deals with Advanced oxidation processes. AOP principle, AOP division and descriotion is included with the strong focus on the ozonation technology. The third chapter presents the textile industry and its wastewaters. The practical part of this thesis consists of two chapters. Chapter 5 describes testing of textile wastewaters decoloration by ozonation in the selected textile copany and its results. This results are used in chapter 6. Chapter 6 is the study of textile industry treatment and reuse in the selected textile company. This study contains the design of two options for wastewater treatment and reuse in the textile processes.

O objetivo deste estudo foi analisar o desempenho de um sistema de captação e tratamento de água do rio Sarapuí, por meio de uma estação de tratamento composta por um sistema de pré-tratamento convencional, ligado a um sistema de separação por membranas de osmose inversa, no Município de Belford Roxo RJ, instalado para fornecer água de processo a instalações industriais. Foi verificado que a água captada encontra-se em condição bastante degradada e que a unidade de tratamento removeu, em média, 97% do teor dos poluentes presentes na água, enquadrando-a nos parâmetros requeridos pelo processo industrial. Foi possível comprovar que o processo de separação por osmose inversa pode ser utilizado em escala industrial, proporcionando ganhos econômicos consideráveis, além de evitar o consumo de água potável para fins de processos industriais e, ainda, contribuir para a retirada de carga orgânica de uma fonte degradada
The objective of this study was to analyze the performance of a system to capture and treat water from Sarapuí river through a treatment system consisting of a conventional pré-treatment stage, linked to a reverse osmosis separation system membranes, in the city of Belford Roxo - RJ, installed to provide process water for industrial plants. It was found that the water is captured in highly degraded condition and the treatment plant removed an average of 97% of the pollutants in the water, fitting the parameters required by the industrial process. It could be demonstrated that the separation process by reverse osmosis can be used on an industrial scale, providing significant economic gains, and avoid the consumption of potable water for industrial processes and also contribute to the removal of organic pollutants from a degraded source

碩士
明志科技大學
環境與安全衛生工程系環境工程碩士班
105
This study evaluated the treatability of disperse dyeing wastewater at the real plant, comprising an anoxic reactor, four activated sludge treatment unit and an aerobic membrane bioreactor. The efficiency of the treatment unit in the plant was analyzed, and the effect of the addition of bacteria on the accumulation of the sludge was discussed. To begin with screening strains to the ability of accumulation from the sludge using textile industries wastewater treatment system sludge as the sludge source.Acinetobacter baumannii, Acidovorax sp., Diaphorobacter sp., Alicycliphilus denitrificans, Chryseobacterium daecheongens, was identified by 16S rRna. Next the decolorization efficiency analysis of microorganisms, the bacteria was cultured in a large quantity and put into real plant unit. The results demonstrated that decolorization efficiency of Disperse Blue 124 by WS01 was found to be 85% at 250 mg/L within 24 hours, when growth medium containing yeast extract compared to other substrates. Bioaugmentation beginning in a bioreactor receive a load of COD(1342 mg/L)and sludge concentration(5.3 g/L). The results showed that the colonization of Dominant bacteria, the COD removal was stable at 80%, while concentration of sludge was 9.5g / L in the system. Overall, the system was demonstrated to be effective in the treatment of the Disperse dyeing wastewater under the operating conditions applied in the study.

Dissertação de Mestrado Integrado em Engenharia Química apresentada à Faculdade de Ciências e Tecnologia
Olive mill wastewater and effluents containing contaminants of emerging concern are one of the most recalcitrant effluents to conventional methods. Thus, this study focus mainly on Fenton-like processes for the treatment of these type of effluents aiming at its release into the natural water bodies. Synthetic olive mill wastewater was submitted to heterogeneous Fenton, using red mud - an alumina residue -, being the source of iron(III). The adsorption of the lab-made effluent onto the catalyst had no significant effects in the pollutants' removal. By testing different amounts of both red mud and \ch{H2O2}, it was possible to achieve around 100\% of the pollutants' degradation and 25\% mineralization. The optimal parameters with which such results were made possible were pH = 3, [\ch{H2O2}] = 100 mg/L and a catalyst load of 1g/L. Toxicity tests made on \textit{Corbicula fluminea} and \textit{Viibrio fischeri} showed a rise in toxicity from the treated solutions, when compared to the original one. As for \textit{Lepidium sativum} the toxicity from the treated solutions proved to be less toxic than the original. The contaminants used were Carbamazepine, Sulphametoxazole and Lorazepam. The solution containing these three compounds was also subject to heterogeneous Fenton-derived processes. Under sunlight, at near-neutral pH, the degradation of the three compounds went over the 50\% degradation line, reaching 62\% for Lorazepam. Synthetic Olive mill waste water was later treated with homogeneous photo-Fenton, using iron sulphate as the source of iron. The optimal conditions were 1 g/L of iron (II), pH = 3 and 100 mg/L of initial load of \ch{H2O2}, reaching 70\% of mineralization, ending up with a residual amount of \ch{H2O2} of approximately 23 mg/L, halved by the 50 mg/L obtained by homogeneous Fenton. Regarding iron removal processes, both failed to meet the 2 mg/L limit of iron allowed to be disposed. However, more experimental test have to be made to support the results obtained.
Efluente sintético proveniente da indústria do azeite e efluentes com contaminantes de preocupação emergente são dos efluentes mais recalcitrantes aos métodos convencionais. Assim, este estudo foca-se principalmente nos processos do tipo Fenton para o tratamento destes tipos de efluentes, visando a sua libertação nos corpos aquáticos naturais.O primeiro foi submetido a Fenton heterogéneo, usando red mud - um resíduo da alumina - sendo esta a a fonte de ferro(III). A adsorção do efluente no catalisador não teve efeitos significativos na remoção dos poluentes. Testando diferentes quantidades de red mud e \ch{H2O2}, foi possível atingir cerca de 100\% da degradação dos poluentes e 25\% de mineralização. Os parâmetros óptimos a partir dos quais tais resultados foram possíveis foram pH = 3, [\ch{H2O2}] = 100 mg/L e uma concentração inicial de catalisador de 1g/L. Testes de toxicidade realizados em \textit {Corbicula fluminea} e \textit {Viibrio fischeri} mostraram um aumento na toxicidade das soluções tratadas, quando comparadas com a solução original. Quanto à \textit {Lepidium sativum}, a toxicidade das soluções tratadas mostrou-se menos tóxica do que a solução original. Os contaminantes utilizados foram Carbamazepina, Sulphametoxazole e Lorazepam. A solução, contendo estes três compostos, foi também sujeita a processos derivados de Fenton heterogéneos. Sob a luz do sol, a pH quase neutro, a degradação dos três compostos ultrapassou a linha de 50 \% de degradação, atingindo 62\% no caso referente ao Lorazepam.Efluente sintético proveniente da indústria do azeite foi, desta feita, tratado com foto-Fenton homogéneo, utilizando sulfato de ferro como fonte de ferro(II). As condições ótimas foram 1 g/L de ferro (II), pH = 3 e 100 mg/L de carga inicial de \ch{H2O2}, atingindo 70\% de mineralização, terminando com uma quantidade residual de \ch {H2O2} de aproximadamente 23 mg/L, sendo aproximadamente metade dos 50 mg/L obtida pelo Fenton homogéneo. Em relação à Permuta iónica, a resina Dowex provou ser a escolha mais adequada em comparação às resinas Purolite e Lewatit. Em relação aos processos de remoção de ferro, ambos falharam em atingir o limite de 2 mg / L de ferro que pode ser libertado para o meio. No entanto, mais testes experimentais devem ser feitos para sustentar os resultados obtidos.

The concern with water quality problems worldwide has led to the improvement of water/wastewater treatment processes. In this PhD project, industrial water and drinking water treatments using membrane processes were investigated in three different case studies. The main aim of these works was the assessment, optimisation and validation of the process’s technologies for the respective case studies. These studies included in a laboratory stage followed by a pilot-scale stage. The first case study contemplates residual water from a rubber industry presenting high chemical oxygen demand (COD). The impact of retrofitting of the existent wastewater treatment process with the replacement of the previously used evaporator with an integrate system (nanofiltration+ evaporator), was evaluated. Two modes of operation were considered, batch and continuous, depending on the daily flowrate of water to be treated in this industry. The second case study addresses surface water treatment, for production of drinking water with a high chemical and microbiological quality, required by the current legislation. The research was focused on the validation of a multibarrier system incorporating nanofiltration and UV photolysis performed at three different locations of the surface drinking water production line. The third case study focuses on a novel treatment process dealing with groundwater contaminated by arsenic (in its inorganic arsenate form) with the purpose to be applied in rural areas located far from centralised drinking water supply infrastructures. It has been a challenge worldwide to treat arsenic contaminated drinking water in order to meet the current strict regulation standard for As. In this research, an ion exchange membrane process, integrating Donnan dialysis with precipitation of this target pollutant was proposed. This work explored the feasibility of arsenic removal from water streams containing sulphate, which strongly competes with arsenate and is preferentially transported through strong-base anion-exchange membranes. Subsequently, the optimisation of arsenic removal from drinking water by the process proposed was performed by using a response surface methodology (RSM). A systematic analysis of the three case studies was carried out and is presented in this thesis in order to provide a deeper insight into the treatment processes studied (theoretical and practical aspects), which makes the proposed solutions also applicable to other water/wastewater treatment cases, facing similar challenges.

博士
國立中山大學
環境工程研究所
95
The purposes of this study are：(1) comparing the treatment efficiency with advanced and traditional drinking water treatment plants in southern Taiwan；(2) assessing the treatment efficiency and formation of disinfection by-products in advanced water treatment processes；(3) assessing the feasibility of wastewater recycling and treatment efficiency of wastewater treatment units；(4) evaluating corrosion of drinking water transportation pipelines and reproducing of chlorination by-products. This study found that the removal efficiency of turbidity, iron, manganese, coliform group and total bacterial count were approximately 99% by advanced and traditional purification processes. The concentrations of ammonia-N (NH3-N), nitrite nitrogen and nitrate nitrogen were lower drinking water quality standard. Pellet softening process was designed following coagulation/sedimentation unit to increase 8~14% and 6~20% removal efficiency of alkalinity and total hardness (TH) concentrations. The removal efficiency of total dissolved solids (TDS) was approximately 3~15% by advanced water treatment processes better than traditional water treatment processes. In the formation of disinfection by-products (DBPs), the trihalomethanes (THMS) and haloacetic acid (HAA5) were efficiently decreased by advanced purification processes. Bromate concentrations which lower detection limit were treated by ozonation process during the study periods. Advanced treatment processes should control the dosage of ozone and post-chlorine to avoid production of DBPs. In wastewater reuse, the treatment efficiency of suspended solids (SS) was 48∼99%, respectively, showing the significant removal efficiency of the wastewater process. However, the removal efficiencies of NH3-N, total organic carbon (TOC) and chemical oxygen demand (COD) are limited by wastewater treatment processes. Because NH3-N, TOC and COD of the mixing supernatant and raw water are regulated raw water quality standards, supernatant reuse is feasible and workable during wastewater processes at this plant. Overall, analytical results indicated that supernatant reuse is feasible. The Chengcing Lake water treatment plant significantly reduced alkalinity, Ca2+ concentration and TH concentration via pellet softening treatment: however, reducing the Langelier saturation index (LSI) value of water could cause some adverse effects on distribution systems. Operational conditions by Pingding water treatment plant was added base to water can be tried to adjust pH to maintain a slightly positive LSI value, whereas for water with low hardness and alkalinity.

M. Tech. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology
Water pollution caused by organic and inorganic contaminants represents an important ecological and health hazard. Simultaneous treatment of organic and inorganic contaminants had gradually gained great scientific interest. Advanced oxidation processes such as photocatalysis, using TiO2 as a photocatalyst, have been shown to be very robust in the removal of biorecalcitrant pollutants. These methods offer the advantage of removing the pollutants, in contrast to conventional techniques. At present, the main technical challenge that hinder its commercialization remained on the post-recovery of the photocatalyst particles after water treatment. Supporting of the photocatalyst on the adsorbent surface is important as it assists during the filtration step, reducing losses of the materials and yielding better results in degrading pollutants. To overcome this challenge, in this study composite photocatalysts of TiO2/zeolite and TiO2/silica were prepared and investigated to explore the possible application in the simultaneous removal of organic and inorganic compounds from contaminated water. The main objective of this study was to investigate the heterogeneous photocatalytic degradation of organic compounds in the presence of metal ions using composite photocatalysts. The Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Raman spectroscopy (RS) and zeta potential (ZP) analyses were used to characterize the prepared composite photocatalysts. The successive composite photocatalysts were used in a semi-batch reactor under an irradiation intensity of 5.5 mW/m2 (protected by a quartz sleeve) at 25 ± 3°C for the photocatalytic degradation of synthetic textile (methyl orange) and agricultural (atrazine) wastewater in the presence of ions. The effect of operating parameters such as TiO2 composition on supporting material, particle size, composite photocatalyst loading, initial pollutant concentration and pH were optimized. The effects of inorganic salts and humic acid on dye and pesticides degradation were also studied, respectively. The performance of the photocatalyst reactor was evaluated on the basis of color removal, metal ion reduction, total organic carbon (TOC) reduction, intermediates product analysis and modeling of kinetics and isotherms. Different kinetic and isotherm models were introduced and applied in this work. Important aspects such as error functions with the optimal magnitude were used for the selection of the best suitable model.
European Union. City of Mikkeli, Finland. Water Research Commission (RSA)