The elimination of natural organic matter (NOM) is an important aim of water treatment in demineralisation plants of power stations. NOM is regarded as corrosion risk factor in the steam water cycle because of its potential to decompose into low-molecular-weight (LMW) acids and carbon dioxide. Further, the removal of NOM is also one of the main objectives in the drinking water production, since it can cause i) colour, taste and odour problems, ii) formation of carcinogen halogenated disinfection by-products (DBPs) after disinfection with chlorine and iii) bacterial growth in the water distribution system. In earlier studies, it was found that anion exchange is a successful method to remove NOM fractions. However, NOM fractions with low charge density (LMW neutrals and hydrophobic organic carbon (HOC)) and/or large molecular size (biopolymers and particulate organic carbon (POC)) could not be removed in some cases in satisfying quantities. The aim of the present work was to investigate the uptake performance of different anion exchange resins (AERs) in regard to problematic NOM fractions. The AERs differ especially in their functional groups (tertiary versus quaternary amines) and matrix material (polystyrene versus polyacrylic resins). The use of different AERs provides an option to identify possible interactions between adsorbate (NOM fractions) and adsorber (AERs) as well as the mechanism which determine the removal efficiency. The NOM fraction adsorption onto AERs was studied in equilibrium and fixed-bed experiments with three types of starch with different molecular size distributions (model substances for biopolymer fraction) as well as 2-naphthol (model substance for the LMW neutral fraction) at acidic pH (relevant for water in demineralisation plants of power stations) and neutral pH (covering most raw waters). Furthermore, the NOM fraction uptake from “real” acidic and neutral water samples, obtained from a demineralisation plant of a power station, was estimated for different AERs. Results were discussed in terms of size-exclusion, anion exchange and hydrophilic/hydrophobic repulsion. In case that size-exclusion influences the NOM uptake onto AERs, it was found that the smaller the size of the NOM molecules and the higher the water content of the AERs, the more effective the uptake is. Thus, for the removal of biopolymers and POC, polyacrylic resins with high water content could be a good choice. Contrary, polystyrene AERs are the most effective resins in the removal of NOM fractions, if no size-exclusion occurs. They seem to be able to uptake more hydrophilic NOM fractions by polar/ionic interactions between acids/acidic components and tertiary/quaternary amines as well as to remove more hydrophobic NOM fractions by π-π stacking and/or hydrophobic interactions on the polystyrene matrix. Further, it was found that the higher the total volume (anion exchange) capacity of an AER, the higher its NOM removal by polar/ionic interactions can be. At acidic pH, weak/medium base AERs have higher total volume (anion exchange) capacities than strong base AERs, whereas, at neutral pH, strong base AERs have the highest ones. In view of these results, the application of polyacrylic AERs with high water content can be recommended to remove NOM components with large molecular size in demineralisation and drinking water plants. If there is a higher amount of smaller NOM fractions, especially LMW neutrals, than polystyrene weak/medium base AERs should be favoured in demineralisation plants and polystyrene strong base AERs in drinking water treatment plants. From the engineering point of view, breakthrough curve (BTC) prediction models are important for the design of fixed-bed filter. Therefore, two different BTC model approaches were tested in the present study to describe the single-solute adsorption onto AERs: i) the homogenous surface diffusion model (HSDM) with linear driving force (LDF) approach for surface diffusion, known from activated carbon adsorption, and ii) the Glueckauf/Helfferich formulae as an extension of the height equivalent to a theoretical plate (HETP) model, initially used to describe ion exchange processes. It was found that the Glueckauf/Helfferich approach is not only a suitable tool for the fast calculation of BTCs for ionic components, but it can also successfully be applied, after considering the Freundlich model for the mass balance, for the rapid prediction of BTCs for single-solute organic molecules. For competitive BTC predictions, the ideal adsorbed solution theory (IAST) within the LDF model was applied. All calculated BTCs fit the experimental data in a good manner. Thus, the investigated BTC models can be applied for estimating the breakthrough bed volumes of different AERs to avoid leakage of NOM in the drinking or demineralised water caused by overloading. / Die Entfernung von natürlichen organischen Substanzen (NOM) ist ein wichtiges Ziel für die Herstellung von Reinstwasser im Kraftwerksbetrieb, da diese sich im Wasser/Dampf-Kreislauf zu niedermolekularen Säuren und Kohlenstoffdioxid zersetzen können und so ein potentielles Korrosionsrisiko darstellen. Außerdem ist die Elimination von natürlichen organischen Substanzen einer der Schwerpunkte in der Trinkwasseraufbereitung, da NOM im Trinkwasser folgende Konsequenzen verursachen können i) Farb-, Geschmacks- und Geruchsprobleme, ii) Bildung von kanzerogen halogenierten Desinfektionsnebenprodukten nach der Desinfektion mit Chlor und iii) Bakterienwachstum im Wasserverteilungssystem. In früheren Untersuchungen wurde festgestellt, dass Anionenaustauscherharze (AERs) die NOM-Fraktionen in der Regel erfolgreich aufnehmen können. Nur NOM-Fraktionen mit geringer Ladungsdichte (niedermolekulare Neutralstoffe und hydrophober organischer Kohlenstoff) und/oder großer Molekülgröße (Biopolymere und partikulärer organischer Kohlenstoff) können unter bestimmten Bedingungen nicht in zufriedenstellender Menge entfernt werden. Ziel dieser Arbeit war es, das Aufnahmeverhalten unterschiedlicher AERs hinsichtlich problematischer NOM-Fraktionen zu untersuchen. Die AERs unterscheiden sich vor allem in ihren funktionellen Gruppen (tertiäre versus quaternäre Amine) und ihrer Matrix (Polystyren- versus Polyacryl-Harze). Die Verwendung unterschiedlicher AERs erlaubt es, mögliche Wechselwirkungen zwischen Adsorbat (NOM-Fraktionen) und Adsorber (AERs) und die Mechanismen, die die NOM-Aufnahme entscheidend bestimmen, zu identifizieren. Die Entfernung von NOM-Fraktionen durch AERs wurde in Gleichgewichts- und Festbett-versuchen mittels dreier Stärketypen mit unterschiedlicher Molekülgrößenverteilung (Modellsubstanzen für die Biopolymere) und 2-Naphthol (Modellsubstanz für die Neutralstoffe) unter sauren pH-Bedingungen (relevant für die Herstellung von Reinstwasser im Kraftwerksbetrieb) und neutralen pH-Bedingungen (bedeutsam für die meisten Rohwässer) untersucht. Außerdem sollte das Adsorptionsverhalten von AERs bezüglich verschiedener NOM-Fraktionen unter Einsatz von „real“ neutralen und sauren Wasserproben aus einer Wasseraufbereitungsanlage eines Kraftwerksbetriebes eingeschätzt werden. In dieser Arbeit konnte gezeigt werden, dass falls Größenausschluss die NOM-Aufnahme von AERs beeinflusst, dann ist die Adsorption der NOM-Fraktionen umso größer, je kleiner die NOM-Moleküle sind und je höher der Wassergehalt der AERs ist. Daher kann für die Entfernung von größeren Biopolymeren, der Einsatz von AERs mit Polyacryl-Matrix und hohem Wassergehalt die beste Option sein. AERs mit Polystyren-Matrix besitzen die höchste Aufnahmekapazität für NOM-Fraktionen, falls kein Größenausschluss auftritt. Es scheint für sie möglich zu sein, sowohl hydrophile NOM-Fraktionen durch polare/ionische Wechselwirkungen zwischen NOM Säuren/sauren Komponenten und tertiären/quaternären Aminen aufzunehmen als auch hydrophobe NOM-Fraktionen durch π-π Anziehungen und/oder hydrophobe Interaktionen an die Polystyren-Matrix zu binden. Weiterhin konnte gezeigt werden, dass je höher die Gesamtvolumenkapazität eines AERs, desto größer ist die NOM-Entfernung auf Grund von polaren/ionischen Wechselwirkungen. Es gilt, dass schwach/mittel basische AERs im Vergleich zu stark basischen AERs höhere Gesamtvolumenkapazitäten unter sauren pH-Bedingungen besitzen und stark basische AERs die höchsten Gesamtvolumenkapazitäten unter neutralen pH-Bedingungen aufweisen. Auf Grund dieser Ergebnisse ist es möglich, die Verwendung von AERs mit Polyacryl-Matrix und hohem Wassergehalt für die Entfernung von NOM-Fraktionen mit großer Molekülgröße in Reinst- und Trinkwasseraufbereitungsanlagen zu empfehlen. Falls es einen höheren Anteil von kleineren NOM-Fraktionen, im Besonderen Neutralstoffen, gibt, sollte die Verwendung von schwach/mittel basischen AERs in Vollentsalzungsanlagen von Kraft-werksbetrieben und stark basischen AERs in Trinkwasseraufbereitungsanlagen bevorzugt werden. Vor allem im Hinblick auf technische Anwendungen ist es wichtig, Durchbruchskurven (BTC) vorausberechnen zu können. In der vorliegenden Arbeit wurden zwei Modellansätze für die Berechnung von BTCs für die Einkomponentenadsorption getestet: i) das homogene Oberflächendiffusionsmodell mit linearer Triebkraft (LDF), bekannt aus Untersuchungen zur Aufnahme von NOM an Aktivkohle, und ii) die Glueckauf/Helfferich-Formeln, primär verwendet für die Beschreibung von Ionenaustauschprozessen. Es konnte gezeigt werden, dass das Glueckauf/Helfferich-Verfahren nicht nur ein geeignetes Instrument für die schnelle Berechnung von BTCs für ionische Komponenten ist, sondern dass dieses, nach Berücksichtigung des Freundlich-Ansatzes in der Massenbilanz, auch erfolgreich angewendet werden kann, um BTCs für Einkomponentenadsorption von Organika zu berechnen. Für die Vorausberechnung von BTCs für Mehrkomponentensysteme wurde die Theorie der idealen adsorbierten Lösung im LDF-Modell genutzt. Die berechneten BTCs stimmen in guter Qualität mit den experimentell ermittelten BTCs überein. Die Ergebnisse verdeutlichen, dass die untersuchten BTC-Modelle eingesetzt werden können, um Durchbruchspunkte für die jeweiligen AERs zu bestimmen und damit die Gefahr des Schlupfes von NOM ins Trink- bzw. Reinstwasser zu minimieren.

Disinfectants in drinking water can interact with natural organic matter (NOM) to form disinfection by-products (DBPs). Halogenated furanones (including MX and MCA) are a group of emerging DBPs that can account for a significant amount of the total mutagenicity found in drinking water. Source water characteristics and NOM removal capabilities of coagulation can greatly influence the formation of DBPs. This project examines the effects of bench scale coagulation and chlorination tests on NOM removal, DBP formation, and genotoxicity. NOM was characterized using liquid chromatography-organic carbon detection (LC-OCD). Experiments with Ottawa River, Otonabee River, and Lake Simcoe waters show that DBPs decreased with increases in coagulant dosage, due to the removal of NOM during coagulation. DBP formation and speciation was then compared with NOM content to identify specific fractions that contribute to the formation of these DBPs. Genotoxicity was directly linked to MX presence in chlorinated waters.

Komati Power Station has installed a membrane plant consisting of ultrafiltration, double pass reverse osmosis and continuous electro-deionisation to treat cooling tower blowdowns in order to produce demineralised water and to conduct sidestream chemistry control of the cooling water circuit. This plant has replaced the existing ion-exchange plant that was used for the production of demineralised water and thus serves to reduce the loading of mobile salts in the ash dam (90% reduction) by eliminating regeneration effluent from the ion-exchange plant. Due to oil contamination in the cooling water circuit (when oil from oil coolers leaks into the cooling water), the membrane plant was also designed to operate on raw water from either the Nooigdedacht or the Vygeboom Dam or a blend of both dams. This is considered to be an emergency intervention under abnormal conditions to prevent possible irreversible fouling of the membranes due to oil in the cooling water. The Nooigtedach Dam water contains high concentrations of organic matter and is also enriched with nutrients due to raw sewage influent into the Dam water. This poses a challenge with regard to treatment of the high fouling feed water on the membrane plant. Natural organic matter in water has the ability to foul reverse osmosis membranes. This adversely affects the operation of the reverse osmosis process. However, very little information is available regarding the fouling characteristics of natural organic material in the raw and cooling water at Komati Power Station for the reverse osmosis membranes. Therefore, a pilot study was undertaken to determine the influence of natural organic matter on membrane fouling, to optimise the process for the removal of natural organic matter and to assess the ability of two different reverse osmosis membranes to effectively treat the high fouling feed water at Komati Power Station. The ability of a polyethersulphone hollow-fibre ultrafiltration membrane system was first evaluated to remove natural organic matter in the feedwater, by conducting pilot tests, initially without coagulation of the raw water and thereafter with in-line coagulation for organics removal. Jar tests were conducted in the laboratory to determine the most suitable coagulant and dosage for turbidity and natural organic matter removal. Various coagulants were tested and, based on the results of the jar tests, a coagulant (U3000) was identified based on optimal removal of both total organic carbon and turbidity at a dosing level of 20 mg/L. During the operation of the ultrafiltration pilot plant, permeate flow; feed pressure and feed temperature were monitored. Performance of the ultrafiltration membrane was monitored in terms of flux versus time for operation with and without a coagulation process. The results indicated that there was very little total organic carbon removal (maximum removal of 4%) without coagulation and a slight decrease in flux. The flux declined as a result of fouling but could be recovered by performing hydraulic backwashes and CEB procedures. Permeate flux, however, could be maintained at about 90 Lmh (from 642 hours of operation). Since most of the organics passed through the ultrafiltration membrane, it was concluded that the loss in flux was due to colloidal fouling of the membrane. This was observed when the operation was carried out using raw water as feed as well as when cooling water was used. The total organic carbon removal increased to 30% when the plant was operated with inline coagulation. The flux remained relatively stable during the first 600 hours of operation and only decreased significantly during the last 200 hours of operation as a result of fouling. The reduction in flux prior to cleaning was less than the 15% (maximum flux decline of 9.9% during the test period) which is acceptable according to the industry norm of 15%. It appeared that flux could be maintained at around 90 Lmh which was about the same as when no coagulant was applied. The 30% total organic carbon reduction that was obtained was not sufficient to reduce the organics to the level of 6mg/L dissolved organic carbon that was specified by the membrane manufacturer for the standard brackish water reverse osmosis membrane. Two reverse osmosis membranes – the standard brackish water reverse osmosis membrane (BW30-2540) and the extra-low-fouling membrane (BW30XFR-2540) – were assessed in terms of their ability to remove dissolved organic carbon, ease of cleaning of the membrane and the ability to recover flux after cleaning. This was done to establish which membrane is more suited to Komati’s high-fouling feedwater. The evaluation of the performance of the two reverse osmosis membranes was conducted using pre-treated water (filtered water after in-line coagulation, anti-scalant and biocide dosing) as well as using water that was not pre-treated. During operation (under both conditions), the normalised permeate flux, conductivity, dissolved organic carbon and organics absorbing at UV254 were monitored. It was established that in terms of flux decline that the extra low-fouling membrane gave slightly superior performance to that of the standard membrane, achieving longer production runs (up to 5 days compared with 3 days achieved by the standard brackish water membrane) without requiring chemical cleaning. The low fouling membrane achieved better CWF recovery after the cleaning cycles (81.26% Lmh of the virgin membrane on the occasions when there was flux loss) compared to the standard membrane (restored to 77.35% of CWF of the virgin membrane) when using untreated feed water. This performance improved when pre-treated feed water was used and the low fouling membrane’s CWF regained after the CIP was 95.89% which was within the industry norm of a flux recovery of 95%, indicating that the CIP had been effective. It was determined that the TOC rejection of the low-fouling membrane was higher (average TOC rejection of 97%, maximum TOC rejection of 99%) than that of the standard membrane (average TOC rejection of 95.3%, maximum TOC rejection of 97%). Preliminary efforts to optimize the pre-treatment for organics removal in order to reduce organic loading for the RO membranes confirmed that the use of granular activated carbon and use of an organic scavenger resin might not be economically feasible due to the relatively quick TOC breakthrough (8910BV, approximately 18000BV and less than 18000BV for the Filtrasorb 300, Filtrasorb 400 and organic scavenger resin, respectively). Although further investigations should still be conducted, the preliminary results indicate that it would be beneficial to also identify other options that can be further investigated for optimization of organics removal at Komati Power Station. Decline in the normalised flux as well as the evidence of biofouling were witnessed during the pilot operation suggesting that the membranes were fouled. Autopsies were performed on both membranes to identify foulants responsible for the decline in flux that was observed during the pilot study. The results did not indicate an organic foulant on the membrane surface. Biofouling should however, be monitored in the main plant as this was suspected to have resulted in the flux decline during the pilot study. The low fouling membrane demonstrated a better capability to treat the Komati raw and cooling water and would be expected to achieve lower operating costs for the plant (CIP costs and membrane replacement costs) while achieving better organics removal and it is therefore recommended that the low-fouling membranes be used at Komati Power Station as they are superior to the standard membrane and the cost of the low-fouling membranes is comparable to that of the standard membrane. While this would provide somewhat better performance than that obtained with the standard brackish water membranes, it is proposed that further investigation into pre-treatment optimization for organics removal as well as more efficient cleaning solutions be investigated to improve the performance and economics of the main water treatment plant at Komati power Station. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Chemical Engineering / unrestricted

Chlorine has effectively reduced the prevalence of waterborne diseases, however there are secondary consequences to this public health advancement. Disinfection byproducts (DBPs) are chemicals formed when chlorine reacts with natural organic matter (NOM) in water. A new class of DBPs, halobenzoquinones (HBQs), has recently been identified and data suggests it could be potentially carcinogenic and up to 1000 times more toxic than some regulated DBPs. So far, in vitro studies have assessed HBQ toxicity without taking into account its transformation in cell media into potentially less toxic compounds. This study evaluated the toxic effects of one HBQ, 2,6-DCBQ, and its transformed derivatives on colon epithelial and liver hepatoma cell lines by measuring intracellular reactive oxygen species production and cell viability post-DCBQ exposure. In addition, to better quantify the trade-off between exposure to waterborne pathogens and 2,6-DCBQ, the inactivation of a virus indicator (MS2), and formation of DCBQ were determined in chlorinated surface waters. Dose-dependent toxic effects were observed in both cell lines and transformed DCBQs were observed to be less toxic than their parent compound. MS2 inactivation occurred immediately post-chlorination, but DCBQ was detected simultaneously. Such findings indicate that this compound is toxic to human cells, including colon epithelial cells, which may be pertinent due to the possible association between chlorinated waters and colon cancer. Findings also suggest this DBP may be relevant in developing countries because HBQs may form in point-of-use chlorinated drinking waters. Furthermore, observed reduction in toxicity of media-transformed DCBQs calls current literature on HBQ toxicity into question.

<p>Cilj ovog rada bio je da se u laboratorijskim uslovima ispitaju efekti odabranih<br />unapredenih procesa oksidacije (Fenton proces, ozonizacija, TiO2-katalizovana ozonizacija,<br />perokson proces i TiO2-katalizovan perokson proces) i koagulacije na sadržaj i strukturu<br />prirodnih organskih materija u vodi, kao prekursora dezinfekcionih nusprodukata hlora.<br />Karaterizacija POM frakcionisanjem pre i nakon navedenih oksidacionih tretmana i<br />koagulacije izvr&scaron;ena je u cilju ispitivanja mehanizama oksidacije i uklanjanja POM, kao i<br />utvrdivanja promene reaktivnosti prekursorskog materijla DBP (trihalometana i halosircetnih<br />kiselina, kao najvi&scaron;e zastupljenih DBP, i haloacetonitrila, hlorpikrina i haloketona, kao<br />nedovoljno istraženih, visoko prioritetnih &bdquo;DBP u razvoju&ldquo;).<br />Analizom hemijskih karakteristika prirodnog matriksa utvrdeno je da voda sadrži<br />visoke koncentracije prirodnih organskih materija (DOC sirove iznosi 9,92&plusmn;0,87 mg/L) uz<br />dominaciju materija hidrofobnog karaktera (14% huminskih i 65% fulvinskih kiselina). U<br />slucaju sintetickog matriksa (sadržaj DOC 11,2&plusmn;0,37 mg/L) zastupljena je samo frakcija<br />huminske kiseline, te je iz tog razloga sinteticki matriks znatno hidrofobniji u odnosu na<br />prirodni. Veci stepen hidrofobnosti sintetickog matriksa u poredenju sa prirodnim matriksom,<br />rezultovao je i vecim sadržajem prekursora najzastupljenijih dezinfekcionih nusprodukata<br />hlora, THM i HAA. Vrednosti za PFTHM iznose 438&plusmn;88,2 &mu;g/L za prirodni matriks,<br />odnosno 3646&plusmn;41,3 &mu;g/L za sinteticki matriks, dok PFHAA prirodnog matriksa iznosi<br />339&plusmn;68,9 &mu;g/L, odnosno 559&plusmn;20,5 &mu;g/L za sinteticki matriks. Sadržaj HAN, CP i HK je<br />znatno niži u poredenju sa prekursorima THM i HAA. PFHAN iznosi 3,65 &mu;g/L za prirodni,<br />odn. 7,98 &mu;g/L za sinteticki matriks, dok prekursori CP nisu detektovani. Prekursori HK su<br />zastupljeni samo u strukturi POM prirodnog matriksa i PFHK iznosi 46,9&plusmn;5,08 &mu;g/L.<br />Hidrofoban materijal, kao dominantan u strukturi POM ispitivanih matriksa, je ujedno i<br />osnovni prekursorski materijal THM i HAA, dok su prekursori haloacetonitrila i haloketona u<br />navecoj meri zastupljeni u hidrofilnoj frakciji.<br />Ispitivanjem uticaja Fenton procesa na sadržaj POM, pri optimalnim reakcionim<br />uslovima (pH 5, reakciono vreme od 15 min. i brzina me&scaron;anja 30 o/min), postignuto je u<br />zavisnosti od primenjene doze Fe2+, molarnog odnosa Fe2+ i H2O2 i matriksa 80-95%<br />smanjenja saržaja DOC, 70-99% PFTHM, 37-92% PFHAA. Kao posledica uklanjanja POM<br />oksidaciojom i koagulacijom, zabeležene su blage fluktuacije u sadržaju prekursora HAN, CP<br />i HK.<br />Ispitivanjem uticaja ozonizacije u vodi pri razlicitim pH na sadržaj i strukturu POM<br />utvrdeno je da je ozonizacija u baznoj sredini efikasnija za uklanjanje POM u odnosu na<br />ozonizaciju u kiseloj sredini. Katalizovanje procesa ozonizacije primenom TiO2 u vodi<br />razlicitim pH unapreduje smanjenje sadržaja kako ukupnih organskih materija, tako i<br />specificnih prekursora DBP u poredenju sa ozonizacijom. Najefikasnije smanjenje sadržaja<br />POM postignuto je TiO2-O3 procesa u baznoj sredini primenom 3,0 mg O3/mg DOC i 1,0 mg<br />TiO2/L (30% DOC, 92-100% PFTHM, PFHAA, PFHAN i PFHK). TiO2-O3 proces pri svim<br />pH vrednostima produkuje manji sadržaj CP u odnosu na ozonizaciju. Veca efikasnost<br />primenjenih procesa u smanjenju sadržaja POM sintetickog matriksa u odnosu na prirodni<br />ukazuju da je frakcija huminske kiseline podložnija oksidacionom tretmanu u odnosu na<br />fulvinsku, kao dominantnu frakciju POM prirodnog matriksa. Kada je u pitanju mehanizam<br />oksidacije POM ispitivanih matriksa, primenom ozonizacije i TiO2-O3 procesa, pri svim pH<br />postignuta je potpuna oksidacija frakcije huminske kiseline do fulvinske kiseline i hidrofilnih<br />jedinjenja. U slucaju ozonizacije, sa povecanjem pH vrednosti sredine, usled povecane<br />produkcije hidroksil radikala iz ozona, povecao se i udeo odnosno sadržaj DOC u hidrofilnoj<br />frakciji ozonirane vode (86%-90%). Raspodela DOC nakon TiO2-O3 procesa pri svim pH<br />vrednostima je oko 70% i 50% u hidrofilnoj frakciji prirodnog i sintetickog matriksa, redom.<br />Frakcija koja se dominantno formira nakon navedenih oksidacionih tretmana je hidrofilna nekisela<br />frakcija. Frakcionisanjem POM nakon oksidacionih tretmana je utvrdeno da su<br />prekursori THM i HAA kako hidrofobne aromaticne strukture, tako i hidrofilna polarna<br />jedinjenja, dok je najreaktivniji prekursorski materijal HAN, CP i HK sadržan u hidrofilnoj<br />frakciji POM.<br />Uvodenjem H2O2 u proces ozonizacije (O3/H2O2 i iO2-O3/H2O2) u slabo baznoj<br />sredini (pH 7-7,5) postignut je jo&scaron; veci stepen oksidacije POM i povecanje udela hidrofilnih<br />struktura (oko 88%) ispitivanih matriksa u odnosu na ozonizaciju i iO2-O3 (oko 70%),<br />primenom 3,0 mg O3/mg DOC; O3:H2O2=1:1 i 1,0 mg iO2/L. Povecanje sadržaja prekursora<br />THM i HAA samo u slucaju prirodnog amtriksa posledica je povecanja reaktivnosti frakcije<br />fulvinske kiseline nakon O3/H2O2 i iO2-O3/H2O2 procesa, u kojoj su ujedno i prekursori HK<br />najzastupljeniji. Najveci sadržaj azotnih DBP (HAN i CP) sadrži hidrofilna frakcija POM.<br />Ispitivanjem kombinovanih procesa ozonizacije i TiO2-O3 i koagulacije utvrdeno je da<br />oksidacioni tretmani imaju pozitivne efekte u uklanjaju POM koagulacijom. Maksimalna<br />efikasnost smanjenja sadržaja DOC od 32% postignuto je primenom 3,0 mg O3/mg DOC i<br />200 mg FeCl3/L, dok su ne&scaron;to niže doze ozona pogodne za uklanjanje prekursora DBP (80-<br />89% PFTHM, PFHAA, PFHAN i PFHK, primenom 0,7-1,0 mg O3/mg DOC i 200 mg<br />FeCl3/L). Prekursori CP koji se formiraju ozonizacijom zaostaju u vodi nakon koagulacije.<br />Rezultati dobijeni tokom istraživanja ukazuju da se primenom razlicitih oksidacionih i<br />unapredenih oksidacionih procesa može smanjiti sadržaj POM i prekursora DBP do<br />odredenog stepena. Kao najefikasniji u uklanjaju kako ukupnih organskih materija, tako i<br />specificih prekursora DBP se pokazao Fenton proces. Kada su u pitanju unapredeni procesi<br />oksidacije zasnovani na primeni ozona, uvodenje katalizatora ili H2O2 kao oksidanta u proces<br />ozonizacije, kao i odabir optimalne pH vrednosti procesa može unaprediti oksidabilnost<br />organskih molekula. Pri tom, poznavanje mehanizama oksidacije POM iz razlicitih izvora<br />primenom ozona i/ili hidroksil radikala, kao i mehanizma uklanjanja POM koagulacijom<br />može se primeniti za odabir i optimizovanje odgovarajuceg procesa u tretmanu vode za pice,<br />a u zavisnosti od kvaliteta sirove vode.</p> / <p>The aim of this work was to examine under laboratory conditions the effects of<br />certain advanced oxidation processes (Fenton process, ozonation, TiO2-catalyzed ozonation,&nbsp;peroxone process and TiO2-catalyzed peroxone process) and coagulation on the content,&nbsp;structure and role of natural organic matter in water as the precursors of chlorine disinfection&nbsp;byproducts. The NOM was characterized by fractionation before and after these oxidation&nbsp;treatments and coagulation, in order to investigate NOM oxidation mechanisms and identify&nbsp;the changes in the reactivity of DBP precursor material (trihalomethanes and haloacetic acids,&nbsp;as the most abundant DBP, and haloacetonitriles, chloropicrin and haloketones, as underresearched,&nbsp;high priority &ldquo;emerging DBP&rdquo;).&nbsp;Through analysis of the chemical characteristics of the natural matrix, it was found&nbsp;that the water contains high concentrations of natural organic matter (raw water DOC was&nbsp;9.92 &plusmn; 0.87 mg/L) dominated by substances with a hydrophobic character (14% humic and&nbsp;65% fulvic acids). The synthetic matrix studied (DOC content of 11.2 &plusmn; 0.37 mg/L)&nbsp;contained only the humic acid fraction, and was therefore significantly more hydrophobic&nbsp;compared to the natural one. The greater degree of hydrophobicity in the synthetic matrix&nbsp;relative to the natural matrix resulted in a higher content of precursors of the most frequent&nbsp;chlorine disinfection byproducts, THM and HAA. The THMFP of the natural matrix was&nbsp;438&plusmn;88.2 mg/L, compared to 3646&plusmn;41.3 mg/L for the synthetic matrix, while the HAAFP of&nbsp;the natural matrix was 339&plusmn;68.9 mg/L, compared to 559&plusmn;20.5 mg/L for the synthetic matrix.&nbsp;The contents of HAN, CP, and HK precursors were much lower than the THM and HAA&nbsp;precursors. HANFP were 3.65 mg/L for natural, and 7.98 mg/L for the synthetic matrix,&nbsp;whilst CP precursors were not detected. HK precursors were present only in the structure of&nbsp;the natural NOM matrix, with a HKFP of 46.9&plusmn;5.08 mg/L. Hydrophobic material, as the&nbsp;dominant structure in the investigated NOM matrix, is the basic precursor material of THM&nbsp;and HAA, while the precursors of haloacetonitriles and haloketones are represented mostly in&nbsp;the hydrophilic fraction.<span style="font-size: 12px;">Whilst examining the influence of the Fenton process on the NOM content, under&nbsp;</span><span style="font-size: 12px;">optimal reaction conditions (pH 5, reaction time of 15 min and stirring speed of 30 rpm),&nbsp;</span><span style="font-size: 12px;">depending upon the applied dose of Fe2+, the molar ratio of Fe2+ and H2O2, and the matrix,&nbsp;</span><span style="font-size: 12px;">reductions in the DOC content of 80-95%, in the THMFP of 70-99%, and in the HAAFP of&nbsp;</span><span style="font-size: 12px;">37-92%, were achieved. As a result of removing NOM by oxidation and coagulation, mild&nbsp;</span><span style="font-size: 12px;">fluctuations in the contents of HAN, CP and HK precursors were recorded.&nbsp;</span><span style="font-size: 12px;">The investigation into the effects of ozonation at different pH levels on the content&nbsp;</span><span style="font-size: 12px;">and structure of NOM has shown that ozonation under alkaline conditions is more effective at&nbsp;</span><span style="font-size: 12px;">removing NOM than ozonation under acidic conditions. Catalyzing the ozonation process&nbsp;</span><span style="font-size: 12px;">using TiO2 in water with different pH promotes the reduction of both total organic matter and&nbsp;</span><span style="font-size: 12px;">specific DBP precursors in comparison with ozonation alone. The most effective NOM&nbsp;</span><span style="font-size: 12px;">reduction was achieved using the TiO2-O3 process in alkaline conditions using 3.0 mg O3/mg&nbsp;</span><span style="font-size: 12px;">DOC and 1.0 mg TiO2/L (30% DOC, 92-100% THMFP, HAAFP, HANFP and HKFP). The&nbsp;</span><span style="font-size: 12px;">TiO2-O3 process produces lower amounts of CP at all pH values, relative to ozonation. The&nbsp;</span><span style="font-size: 12px;">applied processes showed increased efficacy in reducing the NOM content of the synthetic&nbsp;</span><span style="font-size: 12px;">matrix compared with the natural matrix, which shows that the humic acids fraction is more&nbsp;</span><span style="font-size: 12px;">susceptible to oxidation treatments than the fulvic acids which are the dominant faction of the&nbsp;</span><span style="font-size: 12px;">natural NOM matrix. Regarding the NOM oxidation mechanism in the investigated matrices,&nbsp;</span><span style="font-size: 12px;">using ozonation and the TiO2-O3 process, complete oxidation of the humic acid fraction to&nbsp;</span><span style="font-size: 12px;">fulvic acids and hydrophilic compounds was achieved at all pH levels. In the case of&nbsp;</span><span style="font-size: 12px;">ozonation, increasing the pH in the matrix lead to an increase in hydroxyl radicals production&nbsp;</span><span style="font-size: 12px;">from ozone, and the proportion or content of DOC in the hydrophilic fraction of ozonated&nbsp;</span><span style="font-size: 12px;">water (86%-90%) increased. The distribution of DOC after the TiO2-O3 process at all pH&nbsp;</span><span style="font-size: 12px;">values was about 70% and 50% in the hydrophilic fraction of the natural and synthetic&nbsp;</span><span style="font-size: 12px;">matrices, respectively. The dominant fraction formed after the oxidation treatments was the&nbsp;</span><span style="font-size: 12px;">hydrophilic non-acid fraction. By NOM fractionation after the oxidation treatments, it was&nbsp;</span><span style="font-size: 12px;">shown that the THM and HAA precursors are hydrophobic aromatic structures and&nbsp;</span><span style="font-size: 12px;">hydrophilic polar compounds, whilst the most reactive precursor materials for HAN, CP and&nbsp;</span><span style="font-size: 12px;">HC are contained in the hydrophilic NOM fraction.&nbsp;</span><span style="font-size: 12px;">Introducing H2O2 into the ozonation process (O3/H2O2 and iO2-O3/H2O2) in weak&nbsp;</span><span style="font-size: 12px;">basic conditions (pH 7 to 7.5) enhances further the degree of NOM oxidation and increases&nbsp;</span><span style="font-size: 12px;">the proportion of hydrophilic structures (88%) in the examined matrices in comparison to&nbsp;</span><span style="font-size: 12px;">ozonation and iO2-O3 (about 70%), using 3.0 mg O3/mg DOC; O3:H2O2=1:1 and 1.0 mg&nbsp;</span><span style="font-size: 12px;">iO2/L. An increase in the THM and HAA precursor contents occurred in the case of the&nbsp;</span><span style="font-size: 12px;">natural matrix as a result of the increased reactivity of the fulvic acid fraction after the&nbsp;</span><span style="font-size: 12px;">O3/H2O2 and iO2-O3/H2O2 processes, and HK precursors were also present. The highest&nbsp;</span><span style="font-size: 12px;">content of nitrogen DBP (HAN and CP) was found in the hydrophilic NOM fraction.&nbsp;</span><span style="font-size: 12px;">By examination of the combined processes of ozonation, TiO2-O3 and coagulation, it was&nbsp;</span><span style="font-size: 12px;">shown that oxidative treatments have a positive effect on NOM removal by coagulation. A&nbsp;</span><span style="font-size: 12px;">maximum efficacy in reducing DOC by 32% was achieved with 3.0 mg O3/mg DOC and&nbsp;</span><span style="font-size: 12px;">200 mg FeCl3/L, whereas slightly lower ozone doses are suitable for the removal of DBP&nbsp;</span><span style="font-size: 12px;">precursors (80-89% THMFP, HAAFP, HANFP and HKFP, using 0.7-1.0 mg O3/mg DOC&nbsp;</span><span style="font-size: 12px;">and 200 mg FeCl3/L). CP precursors which are formed during ozonation remain in the water&nbsp;</span><span style="font-size: 12px;">after coagulation.&nbsp;</span><span style="font-size: 12px;">The results obtained during this investigation show that the application of different oxidation&nbsp;</span><span style="font-size: 12px;">and enhanced oxidation processes can reduce the contents of NOM and DBP precursors to&nbsp;</span><span style="font-size: 12px;">some degree. The most effective process at removing both total organic matter and specific&nbsp;</span><span style="font-size: 12px;">DBP precursors proved to be the Fenton process. With respect to enhanced oxidation&nbsp;</span><span style="font-size: 12px;">processes based upon the use of ozone, by introducing catalysts or H2O2 as an oxidant in the&nbsp;</span><span style="font-size: 12px;">ozonation process and by selecting the optimum pH for the process, the oxidizability of&nbsp;</span><span style="font-size: 12px;">organic molecules can be improved. In addition, knowledge of the NOM oxidation&nbsp;</span><span style="font-size: 12px;">mechanisms from different sources using ozone and / or hydroxyl radicals, as well as the&nbsp;</span><span style="font-size: 12px;">mechanism of NOM removal by coagulation, can be used to select and optimize the most&nbsp;</span><span style="font-size: 12px;">appropriate process in drinking water treatment, depending upon the quality of the raw water.</span></p>

The elimination of natural organic matter (NOM) is an important aim of water treatment in demineralisation plants of power stations. NOM is regarded as corrosion risk factor in the steam water cycle because of its potential to decompose into low-molecular-weight (LMW) acids and carbon dioxide. Further, the removal of NOM is also one of the main objectives in the drinking water production, since it can cause i) colour, taste and odour problems, ii) formation of carcinogen halogenated disinfection by-products (DBPs) after disinfection with chlorine and iii) bacterial growth in the water distribution system. In earlier studies, it was found that anion exchange is a successful method to remove NOM fractions. However, NOM fractions with low charge density (LMW neutrals and hydrophobic organic carbon (HOC)) and/or large molecular size (biopolymers and particulate organic carbon (POC)) could not be removed in some cases in satisfying quantities. The aim of the present work was to investigate the uptake performance of different anion exchange resins (AERs) in regard to problematic NOM fractions. The AERs differ especially in their functional groups (tertiary versus quaternary amines) and matrix material (polystyrene versus polyacrylic resins). The use of different AERs provides an option to identify possible interactions between adsorbate (NOM fractions) and adsorber (AERs) as well as the mechanism which determine the removal efficiency. The NOM fraction adsorption onto AERs was studied in equilibrium and fixed-bed experiments with three types of starch with different molecular size distributions (model substances for biopolymer fraction) as well as 2-naphthol (model substance for the LMW neutral fraction) at acidic pH (relevant for water in demineralisation plants of power stations) and neutral pH (covering most raw waters). Furthermore, the NOM fraction uptake from “real” acidic and neutral water samples, obtained from a demineralisation plant of a power station, was estimated for different AERs. Results were discussed in terms of size-exclusion, anion exchange and hydrophilic/hydrophobic repulsion. In case that size-exclusion influences the NOM uptake onto AERs, it was found that the smaller the size of the NOM molecules and the higher the water content of the AERs, the more effective the uptake is. Thus, for the removal of biopolymers and POC, polyacrylic resins with high water content could be a good choice. Contrary, polystyrene AERs are the most effective resins in the removal of NOM fractions, if no size-exclusion occurs. They seem to be able to uptake more hydrophilic NOM fractions by polar/ionic interactions between acids/acidic components and tertiary/quaternary amines as well as to remove more hydrophobic NOM fractions by π-π stacking and/or hydrophobic interactions on the polystyrene matrix. Further, it was found that the higher the total volume (anion exchange) capacity of an AER, the higher its NOM removal by polar/ionic interactions can be. At acidic pH, weak/medium base AERs have higher total volume (anion exchange) capacities than strong base AERs, whereas, at neutral pH, strong base AERs have the highest ones. In view of these results, the application of polyacrylic AERs with high water content can be recommended to remove NOM components with large molecular size in demineralisation and drinking water plants. If there is a higher amount of smaller NOM fractions, especially LMW neutrals, than polystyrene weak/medium base AERs should be favoured in demineralisation plants and polystyrene strong base AERs in drinking water treatment plants. From the engineering point of view, breakthrough curve (BTC) prediction models are important for the design of fixed-bed filter. Therefore, two different BTC model approaches were tested in the present study to describe the single-solute adsorption onto AERs: i) the homogenous surface diffusion model (HSDM) with linear driving force (LDF) approach for surface diffusion, known from activated carbon adsorption, and ii) the Glueckauf/Helfferich formulae as an extension of the height equivalent to a theoretical plate (HETP) model, initially used to describe ion exchange processes. It was found that the Glueckauf/Helfferich approach is not only a suitable tool for the fast calculation of BTCs for ionic components, but it can also successfully be applied, after considering the Freundlich model for the mass balance, for the rapid prediction of BTCs for single-solute organic molecules. For competitive BTC predictions, the ideal adsorbed solution theory (IAST) within the LDF model was applied. All calculated BTCs fit the experimental data in a good manner. Thus, the investigated BTC models can be applied for estimating the breakthrough bed volumes of different AERs to avoid leakage of NOM in the drinking or demineralised water caused by overloading. / Die Entfernung von natürlichen organischen Substanzen (NOM) ist ein wichtiges Ziel für die Herstellung von Reinstwasser im Kraftwerksbetrieb, da diese sich im Wasser/Dampf-Kreislauf zu niedermolekularen Säuren und Kohlenstoffdioxid zersetzen können und so ein potentielles Korrosionsrisiko darstellen. Außerdem ist die Elimination von natürlichen organischen Substanzen einer der Schwerpunkte in der Trinkwasseraufbereitung, da NOM im Trinkwasser folgende Konsequenzen verursachen können i) Farb-, Geschmacks- und Geruchsprobleme, ii) Bildung von kanzerogen halogenierten Desinfektionsnebenprodukten nach der Desinfektion mit Chlor und iii) Bakterienwachstum im Wasserverteilungssystem. In früheren Untersuchungen wurde festgestellt, dass Anionenaustauscherharze (AERs) die NOM-Fraktionen in der Regel erfolgreich aufnehmen können. Nur NOM-Fraktionen mit geringer Ladungsdichte (niedermolekulare Neutralstoffe und hydrophober organischer Kohlenstoff) und/oder großer Molekülgröße (Biopolymere und partikulärer organischer Kohlenstoff) können unter bestimmten Bedingungen nicht in zufriedenstellender Menge entfernt werden. Ziel dieser Arbeit war es, das Aufnahmeverhalten unterschiedlicher AERs hinsichtlich problematischer NOM-Fraktionen zu untersuchen. Die AERs unterscheiden sich vor allem in ihren funktionellen Gruppen (tertiäre versus quaternäre Amine) und ihrer Matrix (Polystyren- versus Polyacryl-Harze). Die Verwendung unterschiedlicher AERs erlaubt es, mögliche Wechselwirkungen zwischen Adsorbat (NOM-Fraktionen) und Adsorber (AERs) und die Mechanismen, die die NOM-Aufnahme entscheidend bestimmen, zu identifizieren. Die Entfernung von NOM-Fraktionen durch AERs wurde in Gleichgewichts- und Festbett-versuchen mittels dreier Stärketypen mit unterschiedlicher Molekülgrößenverteilung (Modellsubstanzen für die Biopolymere) und 2-Naphthol (Modellsubstanz für die Neutralstoffe) unter sauren pH-Bedingungen (relevant für die Herstellung von Reinstwasser im Kraftwerksbetrieb) und neutralen pH-Bedingungen (bedeutsam für die meisten Rohwässer) untersucht. Außerdem sollte das Adsorptionsverhalten von AERs bezüglich verschiedener NOM-Fraktionen unter Einsatz von „real“ neutralen und sauren Wasserproben aus einer Wasseraufbereitungsanlage eines Kraftwerksbetriebes eingeschätzt werden. In dieser Arbeit konnte gezeigt werden, dass falls Größenausschluss die NOM-Aufnahme von AERs beeinflusst, dann ist die Adsorption der NOM-Fraktionen umso größer, je kleiner die NOM-Moleküle sind und je höher der Wassergehalt der AERs ist. Daher kann für die Entfernung von größeren Biopolymeren, der Einsatz von AERs mit Polyacryl-Matrix und hohem Wassergehalt die beste Option sein. AERs mit Polystyren-Matrix besitzen die höchste Aufnahmekapazität für NOM-Fraktionen, falls kein Größenausschluss auftritt. Es scheint für sie möglich zu sein, sowohl hydrophile NOM-Fraktionen durch polare/ionische Wechselwirkungen zwischen NOM Säuren/sauren Komponenten und tertiären/quaternären Aminen aufzunehmen als auch hydrophobe NOM-Fraktionen durch π-π Anziehungen und/oder hydrophobe Interaktionen an die Polystyren-Matrix zu binden. Weiterhin konnte gezeigt werden, dass je höher die Gesamtvolumenkapazität eines AERs, desto größer ist die NOM-Entfernung auf Grund von polaren/ionischen Wechselwirkungen. Es gilt, dass schwach/mittel basische AERs im Vergleich zu stark basischen AERs höhere Gesamtvolumenkapazitäten unter sauren pH-Bedingungen besitzen und stark basische AERs die höchsten Gesamtvolumenkapazitäten unter neutralen pH-Bedingungen aufweisen. Auf Grund dieser Ergebnisse ist es möglich, die Verwendung von AERs mit Polyacryl-Matrix und hohem Wassergehalt für die Entfernung von NOM-Fraktionen mit großer Molekülgröße in Reinst- und Trinkwasseraufbereitungsanlagen zu empfehlen. Falls es einen höheren Anteil von kleineren NOM-Fraktionen, im Besonderen Neutralstoffen, gibt, sollte die Verwendung von schwach/mittel basischen AERs in Vollentsalzungsanlagen von Kraft-werksbetrieben und stark basischen AERs in Trinkwasseraufbereitungsanlagen bevorzugt werden. Vor allem im Hinblick auf technische Anwendungen ist es wichtig, Durchbruchskurven (BTC) vorausberechnen zu können. In der vorliegenden Arbeit wurden zwei Modellansätze für die Berechnung von BTCs für die Einkomponentenadsorption getestet: i) das homogene Oberflächendiffusionsmodell mit linearer Triebkraft (LDF), bekannt aus Untersuchungen zur Aufnahme von NOM an Aktivkohle, und ii) die Glueckauf/Helfferich-Formeln, primär verwendet für die Beschreibung von Ionenaustauschprozessen. Es konnte gezeigt werden, dass das Glueckauf/Helfferich-Verfahren nicht nur ein geeignetes Instrument für die schnelle Berechnung von BTCs für ionische Komponenten ist, sondern dass dieses, nach Berücksichtigung des Freundlich-Ansatzes in der Massenbilanz, auch erfolgreich angewendet werden kann, um BTCs für Einkomponentenadsorption von Organika zu berechnen. Für die Vorausberechnung von BTCs für Mehrkomponentensysteme wurde die Theorie der idealen adsorbierten Lösung im LDF-Modell genutzt. Die berechneten BTCs stimmen in guter Qualität mit den experimentell ermittelten BTCs überein. Die Ergebnisse verdeutlichen, dass die untersuchten BTC-Modelle eingesetzt werden können, um Durchbruchspunkte für die jeweiligen AERs zu bestimmen und damit die Gefahr des Schlupfes von NOM ins Trink- bzw. Reinstwasser zu minimieren.

<p>Cilj ovog rada je ispitivanje mogućnosti uklanjanja visokih koncentracija organskih i neorganskih materija iz vodenih rastvora &bdquo;Cross-Flow&ldquo; nanofiltracijom primenom spiralno uvijenih membrana. Mogućnosti separacije NOM-a, amonijum-jona i ukupnog arsena su ispitivane na koncentratima-otpadnim vodama dobijenim iz industrijskih nanofiltracionih uređaja i obuhvaćeni su eksperimentima serije NFCP. Izdvajanje visokih koncentracija jona kalcijuma, magnezijuma, gvožđa i mangana je ispitivano iz prirodnih podzemnih voda i izvedeno je u eksperimentima serije NFWP. Određeni su optimalni fluksevi i transmembranski pritisci, kao i koncentracije doziranja kompleksirajućih supstanci. Dobijeni poluindustrijski rezultati su praktično primenjivi u velikoj skali za pripremu pijaće vode kako iz dubokih, tako i iz plitkih akvifera. Primena prikazanih rezultata u pripremi vode za piće od vode dubokih izdani uz značajne u&scaron;tede resursa je namenjena prvenstveno lokacijama u Panonskom basenu. Tretman bunarske vode plitkih izdani je pogodan posebno zbog dodatka organskih kompleksirajućih agenasa koji supstitui&scaron;u uobičajene postupke deferizacije i demanganizacije i na taj način znatno smanjuju kako investicione, tako i eksploatacione tro&scaron;kove postrojenja. Dobijeni rezultati su poslužili kao osnova za izradu idejnog re&scaron;enja industrijskog postrojenja za kondicioniranje pijaće vode od bunarske vode duboke izdani iz regiona grada Zrenjanina, kao i izradu idejnog re&scaron;enja industrijskog postrojenja za kondicioniranje pijaće vode od bunarske vode plitke izdani regiona grada Bačke Palanke za naseljeno mesto Despotovo.</p> / <p>The goal of this thesis was to examine removal possibility of high concentrations of organic and inorganic matter from aquatic solution using &ldquo;Cross-flow&rdquo; spiral wound nanofiltration membranes. Natural organic matter, ammonia ions and total arsenic removal was examined using concentrates &ndash; waste water obtained from industrial nanofiltration plant and they present NFCP experiment series. Removal of high concentrations of calcium, magnesium, iron and manganese ions was a part of NFWP experiments and was conducted using natural groundwater. Optimal fluxes and transmembrane pressures, as well as complexing substances dosage concentrations were determined. Obtained results in semi industrial scale are practically applicable on the large scale plants for drinking water preparation from deep wells, as well as from shallow aquifers. Application of presented results, concerning drinking water preparation from deep wells with significant savings of water resources, is designed especially for locations in Pannonia basin. Shallow aquifer well water treatment is applicable in practice especially because of addition of organic complexation agents that substitutes conventional deferization and manganese removal methods ultimately reducing investment and exploitation costs. On the basis of obtained results, industrial plant that produces drinking water from Zrenjanin aquifer deep well was designed. Furthermore, potable water industrial plant was designed that used shallow aquifer well water located in Bačka Palanka region, settlement Despotovo.</p>

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[pt] A presença de ácidos húmicos (AHs), fração esta representativa da matéria orgânica natural (MON) presente em águas naturais, pode contribuir para a formação de subprodutos de desinfecção (SPDs), como os Trihalometanos (THMs), ao reagirem com o cloro durante a produção de água potável nas estações de tratamento de água (ETAs). Tais subprodutos têm sido amplamente investigados devido a seus efeitos no organismo humano, como por exemplo, o aumento do risco de câncer. Portanto, a remoção deste material orgânico antes da etapa de cloração é necessária para a minimização de tais riscos. O processo de oxidação avançada (POA) baseado em FZV (ferro zero valente) e peróxido de hidrogênio (H2O2) aplicado como uma etapa pré-oxidativa em ETAs foi proposto e investigado quanto à degradação da matéria orgânica, incluindo sua fração relacionada aos AHs. Cortes de ferro metálico comercial (área superficial de 2,56 cm²) foram aplicados ao processo FZV/H2O2 como fonte de FZV de baixo custo de capital. Experimentos em escala de bancada foram conduzidos com água natural (amostras coletadas em lago do Regent’s Park e do Rio Tâmisa, localizados em Londres, Reino Unido) e em solução de AH preparada em laboratório. Alterações na absorbância de UV a 254 nm (UV254), na concentração de carbono orgânico dissolvido (COD) e na formação de Trihalometanos (THMs) foram analisadas para avaliar o desempenho do tratamento FZV/H2O2. Análises de caracterização do FZV e seus respectivos produtos de corrosão foram verificados pelas técnicas de OES (Espectroscopia de Emissão Ótica), MEV (Microscopia Eletrônica de Varredura), DRX (Difração de raios-X), XPS (Espectroscopia de Fotoelétrons Excitados por raios X). Concluiu-se que a remoção da matéria orgânica natural foi influenciada pela dosagem de H2O2, pH inicial e número de ciclos de reuso do FZV. A formação de uma camada passiva na superfície do metal FZV a partir de sua oxidação produziu espécies de óxidos/hidróxidos que podem contribuir para a redução na eficiência de reuso do FZV. A formação do THM clorofórmio foi maior quando o processo FZV/H2O2 foi aplicado sob pH inicial 6,5, indicando valores acima do limite máximo permissível pela legislação brasileira. Experimentos visando verificar a eficiência do POA investigado sobre diferentes corpos hídricos (Lago do Regents Park e Rio Tâmisa) mostraram semelhantes resultados de remoção de COD e UV254. Isto indica a viabilidade de aplicação deste processo oxidativo sobre diferentes águas naturais de superfície, possibilitando a mineralização parcial da MON e uma significativa redução de sua estrutura húmica. As melhores condições experimentais a nível do planejamento estatístico obtidas a partir do tratamento em água natural (Regent s Park) foram pH0= 4.5, FZV= 50 g/L e [H2O2]= 100 porcento de excesso da dosagem estequiométrica, alcançando remoções de 51 porcento e 74 porcento para COD e UV254, respectivamente. / [en] The presence of humic acids (HAs), a fraction that represents the natural organic matter (NOM) present in natural waters, can contribute to the formation of disinfection byproducts (DBPs), such as Trihalomethanes (THMs), when reacting with chlorine during the production of drinking water in water treatment plants (WTPs). Such byproducts have been widely investigated due to their effects on the human organism, such as the increased risk of cancer. Therefore, the removal of this organic material prior to the chlorination step is necessary to minimize such risks. The advanced oxidation process (AOP) based on ZVI (zero valent iron) and hydrogen peroxide (H2O2) applied as a pre-oxidative step in WTPs has been proposed and investigated for the degradation of organic matter, including its HA-related fraction. Commercial metallic iron cuts (surface area of 2.56 cm2) were applied to the FZV/H2O2 process as a source of low capital cost ZVI. Bench-scale experiments were conducted with natural water (samples collected from Regent s Park and Thames River lake, located in London, UK) and laboratory-prepared HA solution. Changes in UV absorbance at 254 nm (UV254), dissolved organic carbon (COD) concentration and THMs formation were analyzed to evaluate the performance of the ZVI/H2O2 treatment. Characterization analyzes of ZVI and their respective corrosion products were verified by OES (Optical Emission Spectroscopy), SEM (Scanning Electron Microscopy), XRD (X-ray Diffraction), XPS (X-ray Excited Spectroscopy) techniques. It was concluded that the removal of natural organic matter was influenced by initial pH, H2O2 dosage, and number of ZVI reuse cycles. The formation of a passive layer on the surface of the ZVI metal from its oxidation has produced oxide/hydroxide species that may contribute to the reduction of ZVI reuse efficiency. The formation of chloroform (i.e. THM) was higher when the ZVI/H2O2 process was applied at initial pH 6.5, indicating values above the maximum limit allowed by the Brazilian legislation. Experiments to verify the efficiency of the investigated AOP on different water bodies (Regent s Park Lake and River Thames) showed similar DOC and UV254 removal results. This indicates the feasibility of applying this oxidative process over different natural surface waters, enabling the partial mineralization of NOM and a significant reduction of its humic structure. The best experimental conditions in the statistical planning obtained from natural water treatment (Regent s Park) were pH0 = 4.5, ZVI= 50 g/L and [H2O2] = 100 percent of stoichiometric excess dosage, reaching 51 percent and 74 percent removals for DOC and UV254, respectively.