No description available.

<p> In this study the influence of several water chemistry parameters on the toxicity of Ni to Daphnia pulex in soft water were tested. A reconstituted soft water (pH 7.8, hardness 31.5 mg/L CaCO3) was used as the basis for culture and testing. Daphnia pulex was chosen as a typical cladoceran, one which can be acclimated to very soft water. An understanding of the influence of water chemistry on Ni toxicity in soft water is relevant because metals have higher bioavailability in soft water. The 48h EC50 in the reconstituted soft water (RSW) was 974 μg/L (16 μM) dissolved Ni (95%CI 830- 1081 μg/L). The following factors were examined for their potential for modifying Ni toxicity: Ca, Mg, Na, K, Cl, pH (3 different approaches used) and natural organic matter (NOM, 2 sources tested). Both Ca and Mg protected against Ni toxicity and the relative effect was greater for Ca. Varying the concentrations of Na, Cl or K did not alter the toxicity of Ni. Tests at different pH showed that as pH increased, Ni toxicity decreased. When the test solution pH was adjusted with the organic buffer 3-morpholinepropanesulfonic acid, there was a clear correlation between increasing pH and increasing EC50. The pH tests using bicarbonate to adjust pH did not show this relationship as clearly. Both types of NOM showed a protective effect on Ni toxicity with Nordic Reservoir NOM having a 4 fold greater effect than that of Suwannee River NOM. This research illustrated that the effect of alterations in water chemistry were generally as predicted within the context of the biotic ligand model (BLM) approach. The data provide the information required to develop a BLM for the acute effects of Ni in soft water.</p> / Thesis / Master of Science (MSc)

A cation exchange method (Chelex 100) that distinguishes weakly bound and strongly bound copper was investigated for its ability to measure bioavailable copper in estuarine waters. Copper bound to the Chelex 100 resin was operationally defined as bioavailable copper. Varying initial copper concentration from 195 to 495 ug/L at a constant 12.5 mg/L natural organic matter (NOM) did not affect percent bioavailability. There were also no noticeable effects when varying total Cu concentration in the presence of 0, 12, and 24 mg/L NOM. An increase in pH from 4 to 8.5 and NOM from 0 mg/L to 12.5 mg/L reduced percent bioavailability. Using the Chelex 100 resin to measure bioavailable copper, about 20 to 40% of the total copper was bioavailable in the absence of NOM, while about 15 to 20% was bioavailable when either 12 or 24 mg/L NOM was present. Acute toxicity bioassays were performed with mysid shrimp (Americamysis bahia) to evaluate the toxic effects of copper in the presence of Suwannee River Fulvic Acid, which served as a source of NOM. Static or static renewal tests, based on EPA method OPPTS 850.1035 with a minimum of 10 mysid shrimp per test condition, were used to determine the LC50 and EC50 of copper and the effects of NOM. Test solutions consisted of artificial synthetic seawater at 20 parts per thousand containing concentrations of 0, 100, 200, 400, 800 ug/L copper with either 0, 12, 24 mg/L NOM. Forty-eight hour acute toxicity tests were performed on larval (2 to 3 day) mysid shrimp that were fed Artemia (brine shrimp); mortality and immobilization were the endpoints. The 48 hour LC50 was 200 ug/L dissolved Cu and 94 ug/L bioavailable Cu without NOM, 340 ug/L dissolved Cu and 98 ug/L bioavailable Cu when 12 mg/L NOM was present, and 495 ug/L dissolved Cu and 105 ug/L bioavailable Cu at 24 mg/L NOM. The consistency of the LC50 measurement using bioavailable Cu suggest that the Chelex 100 resin is a useful technique for toxicity analysis in saline water. / Master of Science

D'enfant intrigué par des inscriptions en gallois, Tolkien évolue vers un apprentissage précoce du latin, du grec et de nombreuses langues anciennes. Sa passion pour les langues ne se dément pas: bientôt il travaille à l'élaboration de langues inventées basées sur le finnois, puis il fonde un club de lecture de sagas en norrois. Dans son étude des langues, il s'intéresse aux anciens textes qui recèlent leur évolution: très vite, pour lui, le langage et le mythe sont indissociables. Le langage génère du mythe et ce dernier survit à travers les langages. Du propre aveu de l'auteur, c'est pour donner vie à ses langues inventés qu'il créa leur monde: « [...] il lui fallait une « histoire » pour lui servir de base. [...] Il mettait ce langage au point, maintenant il lui fallait trouver les gens dont ce serait la langue. » (Carpenter, 2002). En marge de ses recherches universitaires, il construit donc sa mythologie personnelle, un travail étalé sur toute une vie dont quelques vingt ans sur le seul Seigneur des Anneaux pour lequel il s'attarde minutieusement sur chaque mot: « It was begun in 1936, and every part has been written many times. Hardly a word in its 600 000 or more has been unconsidered. » (Carpenter, 1981). En parcourant la biographie de ce linguiste-écrivain, qui peut se surprendre de voir le langage comme personnage principal de son oeuvre Le Seigneur des Anneaux? Son récit se veut une reconstruction moderne basée sur les légendes anciennes qu'il affectionne et il y inclut à cet effet nombre des éléments langagiers, relevant souvent de la pensée mythique, qui donnent à ces récits anciens leur saveur particulière. Parmi ces éléments, nous avons relevé le traitement accordé à la nomination et celui accordé aux manifestations de la parole poétique que sont ces chants et poèmes que l'on retrouve égrenés dans la narration en prose. En premier lieu, nous exposerons l'intérêt de l'auteur pour le langage et les littératures médiévales (principalement germaniques et finnoise), notamment pour leurs techniques langagières particulières. Nous nous appuierons en cela sur ses essais consacrés aux sources et à la genèse du texte (Tolkien, 1981, 1997). Puis, nous mettrons en relief ce qui, de la pensée mythique, éclaire la perspective et l'utilisation par Tolkien du nom et de la parole poétique avec l'appui de l'essai de Mircea Eliade: Aspects du mythe. Ensuite, il nous faudra étudier la littérature médiévale germanique avec l'aide des ouvrages de Régis Boyer y ayant trait. Nous pourrons ensuite nous pencher sur la question du traitement de la nomination dans l'oeuvre de Tolkien: quel est sa nature, son sens et ses fonctions pour le récit et qu'est-ce qui la rattache à la pensée mythique? Enfin, nous nous intéresserons aux nombreux chants et poèmes propres à l'oeuvre. Nous verrons comment ils définissent des cultures, relatent un passé et des mythes; bref, comment ils ajoutent à la cohérence et à la profondeur de l'univers fictif dépeint. Ainsi, et plus que de simples artifices stylistiques, ces manifestations langagières singulières qui imprègnent Le Seigneur des Anneaux participent de la structure même du récit et sont étroitement liées à la pensée mythique: le langage, le mot, a un véritable pouvoir chez Tolkien. Voilà ce que ce travail tendra à démontrer. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Mythe, Nomination, Parole poétique, Fantasy.

Uppsalas dricksvattenförsörjning baseras på konstgjord grundvattenbildning som innebär att vatten från Fyrisån får rinna ned till grundvattnet från infiltrationsbassänger. Detta examensarbete syftar till att undersöka vad som händer med naturligt organiskt material (NOM) i Uppsalaåsen vid konstgjord grundvattenbildning. De viktigaste processerna för minskning av NOM är biologisk avskiljning genom nedbrytning, fysikalisk-kemisk avskiljning genom sorption till metalloxider samt utspädning genom inblandning av naturligt grundvatten. Arbetet bestod av tre delar: 1) analys av vattenkemidata från grundvattenprover, 2) analys av extraktion av TOC, Al och Fe från jordprover för att undersöka utfällning av NOM med metalloxider samt 3) ett inkuberingsexperiment för att utvärdera potentialen för biologisk nedbrytning i löst organiskt material (DOC). Jordproverna hämtades från borrkärnor som tagits på fem platser längs åsen under sommaren 2014. Grundvattenprover togs i 19 brunnar minst en gång per månad från november 2014 fram till april 2015. TOC-halten i grundvattnet är som högst vid infiltrationsbassängerna, ca 15 mg/l. TOC- minskar med 30 % de första 200 metrarna i flödesriktningen men minskningen avtar under grundvattentransporten. I den omättade zonen avskiljs mindre än 10 %. Vattnet i Fyrisån har en varierande sammansättning över ett år, vilket också observerades i provtagningspunkter som ligger närmast infiltrationsanläggningarna. Analys av uran och stabila isotoper visar att dispersion i åsen utjämnar dessa variationer. Analys av UV-absorbans och fluorescens tyder på att det organiska materialet i grundvattnet byter karaktär i den mättade zonen och blir hydrofilt. Resultaten från extraktionerna i jordprover visar på god korrelation mellan Fe och TOC. Bidning till järnoxider antas därför vara den viktigaste avskiljningsmekanismen i åsen. Resultaten indikerar på anrikningar av humuskomplex i de ytligaste jordlagren under sandfiltren samt precis under grundvattenytan i närheten av bassängerna. Inkuberingsexperimentet utfördes genom att grundvatten från fem olika provpunkter sterilfiltrerades. 15 vattenprover tillsattes med inockulat innehållande mikroorganismer och övriga 15 sterila prover användes som referenser. TOC undersöktes varannan vecka på samtliga vattenprover under 1,5 månader. Efter två veckor minskade halten TOC i samtliga prover och referenser med cirka 25 % och var därefter relativt konstant. Sammanfattningsvis sker en snabb minskning av NOM i grundvattnet nära infiltrationsbassängerna. Det antas bero på adsorption till metalloxider och fasta partiklar och biologisk nedbrytning. Minskningstakten av NOM avtar med transportsträckan. Längre bort antas inblandning av naturligt grundvatten vara den viktigaste orsaken till att halten NOM minskar. / The drinking water supply in Uppsala is based on this technique which involves surface water from Fyrisån percolating to the ground water through an infiltration basin. This master thesis aims to evaluate the fate of natural organic matter (NOM) in the Uppsala esker during artificial groundwater recharge. The most important processes for the removal of NOM are biological degradation, physical-chemical sorption to metal complexes and dilution by mixing with natural ground water. The work consisted of three parts: 1) analysis of water chemistry data from groundwater samples, 2) analysis of extractions of TOC, Al and Fe from soil samples to evaluate deposition of NOM with metal oxides, and 3) an incubation test to evaluate the potential for biological degradation in dissolved organic carbon (DOC). Soil samples were collected from drill cores taken from five locations along the Uppsala esker in the summer of 2014. Ground water was sampled in 19 wells at least once every month from November 2014 to April 2015. The levels of TOC in ground water are highest at the infiltration basins, about 15 mg/l. The TOC levels drop by 30 % the first 200 meters in the flow direction, but the removal rate decreases during the ground water transport. Less than 10 % is removed in the unsaturated zone. The water in Fyrisån has a variation in composition during a year, which is also observered in sampling points close to the infiltration basins. Analysis of uranium and stable isotopes shows that dispersion in the esker evens these variations. The analysis of absorbance and fluorescence shows that the NOM changes character in the saturated zone and becomes less humificated and becomes hydrophilic. The results from the extractions in the soil samples show a good correlation between Fe and TOC. Complexes of NOM and iron oxides are thought to be the most important complex in the Uppsala esker. The extractions also indicate that enrichments of humus complexes in the uppermost soil of the infiltration basins and right below the ground water table in several locations near the basins. The incubation test was done by sterilization filtering of ground water from five different locations. Inoculate with microorganisms was added to 15 of these samples, while 15 without inoculate was used as reference samples. Analysis of TOC was done every two weeks during 1,5 months. The levels of TOC decreased by 25 % after two weeks in all samples and reference samples, and were stable afterwards. In summary, a quick decrease of NOM occurs in the groundwater close to the infiltration basins. This is mainly caused by sorption and biological degradation. The removal rate of NOM decreases with distance. Further away from the basins, the most important process for decrease of NOM is mixing with local ground water.

The diploma thesis deals with characterizing properties of non-proteinaceous cellular organic matter (COM) of green alga Chlorella vulgaris in connection with its coagulation using aluminium sulphate and polyaluminiumchloride. As a part of this work, interaction mechanisms were also studied. It has been found out that non-proteinaceous COM of Chlorella vulgaris is made up by saccharides (25 % DOCNP, 21 % of dry biomass of non- protein matter) and other unspecified non-protein substances. It has been found out by fractionation of molecular weights that non-protein COM is formed primarily by substances with MW < 3 kDa and substances with MW > 100 kDa. Coagulation by aluminium sulphate taken place in interval pH 5 - 8,5 and coagulation by polyaluminiumchlorid taken place in interval pH 7 - 10 depending on coagulation agent dose. The maximum DOC removals were 17 - 22 % depending on selected coagulation agent, on its dose and pH. Polyaluminiumchloride showed higher DOC removal rates than aluminium sulphate. The highest effectiveness of coagulation was in the area of neutral pH for both agents. In all the coagulation tests the values of residual concentrations of aluminium were higher than the hygienic limit for drinking water (0.2 mg.L-1 ). Primarily high-molecular matter was removed by coagulation and...

Societies are facing great challenges with obtaining a good quality and quantity of drinking water in the context of climate change. Increases in natural organic matter (NOM) and per- and polyfluoroalkyl substances (PFAS) have been observed in lakes and drinking water the past years, which is of great concern for water treatment plants in Sweden. It is therefore vital to increase the knowledge regarding the distribution of these substances in the environment. The main objective of this project was therefore to further develop a hydrodynamic model for lake Ekoln by including transportation and degradation of NOM. This was to be done by calibrating the model in terms of total organic carbon (TOC) and Water colour (Colour). A second objective was to investigate the requirements to successfully model PFAS in Ekoln for future studies. The study was done using the model MIKE 3 FM, developed by the Danish Hydraulic Institute (DHI) The two variables TOC and Colour, were calibrated separately for the period of February 2017 to September 2018. For TOC the within-lake processes were decay and sedimentation. These were described using a reference decay constant for 20 °C (k0), that was scaled using the Arrhenius temperature coefficient (θ), and sedimentation was represented by a settling velocity (vsm). For Colour the included process was photooxidation. This process was described using a maximum photooxidation rate (kphoto) that was scaled using the Monod relation including parameters for minimum photosynthetically active radiation (PAR) necessary for photooxidation to occur (Imin) and a PAR half saturation constant (I1/2). The calibration of TOC resulted in the following best fit parameters for k0  of 0.001 d-1, θ of 1.07 and vsm of 0.001 md-1. The calibration of Colour resulted in the following best fit parameters for kphoto of 0.0125 d-1, Imin of 0 µmol photons m-2s-1 and I1/2 of 4 µmol photons m-2s-1. Overall it can be concluded that the chosen processes managed to capture the seasonal variations of TOC and Colour, and the calibrated parameter values are in line with similar studies. The assumption of not including autochthonous input proved to be the biggest source of error in the calibration of TOC but proved to have a minor influence on the calibration of Colour. To achieve a more realistic representation of photooxidation in the vertical profile, for the simulation of Colour, more processes should be considered to be added in the model in future studies. The results presented in this study contributes with increased knowledge of carbon budgets in lakes and can be used to predict water quality hazards connected to climate change and extreme events. The limited access to PFAS data for Ekoln, constrained the study of PFAS and only two sources could therefore be studied: The sewage treatment plant Kungsängsverket and precipitation. The results showed that the simulated concentrations of PFAS in Ekoln only accounted for 40 % of the observed concentrations. It could further be concluded that the contribution from precipitation is negligible. For future studies it is judged to be vital to include Fyrisån as a PFAS source, and to look into processes that influence PFAS distribution, such as sedimentation and adsorption to organic matter. / Samhällen står idag inför stora utmaningar vad gäller att tillhandahålla god kvalitet och kvantitet av dricksvatten under rådande klimatförändringar. De senaste åren har det observerats ökande halter av naturligt organiskt material (NOM) och per- och polyfluorerade alkylsubstanser (PFAS) i sjöar och dricksvatten, vilket är bekymmersamt för Sveriges vattenreningsverk. Det är därför av största vikt att öka kunskapen om dessa ämnens distribution i miljön. Huvudsyftet med denna studie var därför att vidareutveckla en hydrodynamisk modell för sjön Ekoln så att den även inkluderar transporten och nedbrytningen av NOM. Detta utfördes genom att kalibrera modellen för totalt organisk kol (TOC) och Vattenfärg (Färg). Ett andra syfte var att undersöka vilka förutsättningar som krävs för att kunna modellera PFAS på ett korrekt sätt i Ekoln. Studien utfördes i modellverktyget MIKE 3 FM, utvecklat av DHI.  De två variablerna TOC och Färg kalibrerades separat för perioden februari 2017 – september 2018. Processerna som valdes att påverka TOC var nedbrytning och sedimentation. Dessa processer beskrevs med hjälp av en referens-nedbrytningskonstant för 20 °C (k0), vilken anpassades med hjälp av Arrhenius temperaturkoefficient (θ) och sedimentation beskrevs med hjälp av en sedimentationshastighet (vsm). Färg påverkades endast av processen fotooxidation vilken beskrevs med en maximal hastighet för fotooxidation  (kphoto) som anpassades med hjälp av Monods relation. Anpassningen skedde med hjälp av parametern för minimal fotosyntetiskt aktivt ljus (PAR) för att fotooxidation ska ske (Imin) samt en PAR halv mättnads konstant (I1/2) .  Kalibreringen resulterade i värden för k0 av 0.001 d-1, θ av 1.07 och vsm av 0.001 md-1. Kalibreringen för Färg resulterade i värden för kphoto av 0.0125 d-1, Imin av 0 µmol fotoner m-2s-1 och I1/2 av 4 µmol fotoner m-2s-1. Det kan konstateras att de valda processerna lyckas med att beskriva säsongsvariationerna av både TOC och Färg och att de kalibrerade parametervärdena stämmer överens med litteraturen. Antagandet om att inte inkludera autoktont tillförsel av organiskt material (NOM från ytvatten), visade sig vara den största felkällan i simulering av TOC, men visade sig ha en mycket liten påverkan på simuleringen av Färg. För en mer realistisk bild av fotooxidations spridning i djupled, för simuleringen av Färg, bör fler processer övervägas att inkluderas i modellen för framtida studier.  Studien av PFAS var begränsad av tillgången till data, vilket medförde att endast två källor av PFAS till Ekoln analyserades: reningsverket Kungsängsverket och nederbörd. Resultaten visade att den simulerade koncentrationen av PFAS endast motsvarade 40 % av den observerade. Vidare kunde det konstateras att tillförsel av PFAS från regn kan antas vara försumbar. För framtida studier av PFAS i Ekoln bedöms det vara avgörande att inkludera Fyrisån som en källa, samt att vidare undersöka processer som påverkar transporten av PFAS så som sedimentation och adsorption till organiskt material.

Geosorption processes play an important role as retardation mechanism in subsurface transport of organic water constituents. Geosorption behaviour of Ionisable Hydrophobic Organic compounds (IHOCs) especially influence of dissolved natural organic materials on their sorption coefficients is poorly investigated. In this study influence of pH and NOM on the sorption of three different phenols (2-methyl-4,6-dinitrophenol, 2,4,6-trichlorophenol and pentachlorophenol) on a natural sandy aquifer material collected from a bank filtration site was studied in flow through column experiments. In first step the sorption coefficients of investigated phenols from NOM-free solutions with different pH values were determined. Single as well as multi (mixed) solutes experiments confirmed that there was no competition effect among the phenols investigated. An increasing sorption/retardation was observed with decreasing pH. A linear model was used to resolve the apparent sorption coefficient into an ionised species and neutral species component. This model allows a prediction of apparent sorption coefficients for any pH value. Analysis of data also revealed that the anion of 2-M-4,6-DNP show no significant sorption and a simple model based on the neutral form sorption coefficient was useful in predicting the apparent sorption coefficient over the entire pH range investigated. For 2,4,6-TCP and PCP, the anion sorption is much lower than that of the neutral species but cannot be neglected completely. For PCP, the anion sorption is even as high as the sorption of neutral 2,4,6-TCP. Thus for such hydrophobic phenols prediction of sorption based only on the partitioning of non-dissociated species may lead to an error, especially at high pH values (&amp;gt; pKa), where ionised form is present predominantly. On the other hand prediction of sorption based on the partitioning of non-dissociated species is useful at pH &amp;lt; pKa or in cases where the anion sorption can be neglected. The advantage of this prediction is that it allows predicting the pH-dependent sorption only on the basis of LFER correlations. It was shown that the organic carbon normalized sorption coefficients of the neutral forms of the phenols can be predicted better by solubility based regression correlations than by n-octanol-water partition coefficient based correlations. In second step the apparent sorption coefficients of investigated phenols from NOM-containing solutions (mixed solution of phenols dissolved in natural river water) with different pH values were determined; the sorption coefficients obtained from this step were compared with the results of the first step examinations. Analysis of data revealed that binding of 2-M-4,6-DNP by dissolved humic substances (DHS) reduces the sorption coefficient significantly. In contrast to it, the sorption of the more hydrophobic chlorinated phenols was not affected by DHS. A strong reduction of sorption onto aquifer material caused by complex formation with DHS was also observed for a second nitrophenol (2,4-DNP) and seems to be typically for nitrophenols. A combined sorption and complex formation model was proposed which could be used successfully to describe the effect of pH and NOM concentration on sorption reduction and to estimate binding constants. The binding constant found for 2-M-4,6-DNP is much higher than those reported by Ohlenbusch and Frimmel, 2001, for chlorophenols associated with Aldrich humic acid. This can be interpreted as a result of specific interactions between the nitrophenol and DHS. This phenomenon may cause an increase of the amount of nitrophenols, which can be transported with the groundwater flow and has to be considered in transport modelling, especially in cases where pH is lower than pKa. The models developed here are a useful tool to describe the influence of pH and NOM on geosorption processes and to estimate the Kd values which have to be used in transport models.

Norrvatten är den fjärde största dricksvattenproducenten i Sverige. De producerar och distribuerar dricksvatten till 14 kommuner norr om Stockholm. Norrvatten har under en tid studerat alternativa processer för att optimera och öka produktionskapaciteten och effektiviteten i deras dricksvattenreningsverk vid Görvälnverket.  I detta projekt har en pilotanläggning använts för att studera och optimera ett hybridprocessteg bestående av ett koagulerings- och ultrafiltreringssteg med syfte att avlägsna humusämnen från ytvatten. Effekten av pH, reaktionstid och olika matarvattenkvaliteter (Görväln, Fyrisån och sandfiltrat) analyserades genom en serie experiment utförda med pilotanläggningen. Den mest optimala placeringen av ett eventuellt ultrafiltreringssteg i reningsprocessen studerades även.   Resultaten från experimenten påvisade att pH mellan 6.1 och 6.7 inte hade någon effekt på reningen av fDOM. Mer signifikanta skillnader i rening kunde observeras mellan de olika koaguleringsdoserna, vilket indikerar att denna parameter är viktigare än pH. Reaktionstiden hade ingen märkbar effekt på anläggningens reningseffektivitet. Däremot ökade transmembrantrycket tio gånger snabbare under experimenten med den kortare reaktionstiden. Dessa resultat antyder att de bildade flocken var mindre och därmed blev mer tätt packade i ultrafiltret vilket i sin tur lett till det snabbt ökande trycket i membranet. En avskiljning av minst 50 %, men inte mer än 60 %, av det ingående fDOM kunde uppnås med alla matarvatten utom sandfiltratet, som hade en reningseffektivitet på 18 %. Vattnet från Fyrisån visade sig vara en utmaning för anläggningen att hantera, då trycket snabbt byggdes upp i membranet vilket tyder på att anläggningen inte klarar för starkt förorenade vatten. Resultaten från sandfiltratexperimenten visade att ett ultrafiltreringssteg efter sandfiltren skulle kunna vara en möjlig placering av ultrafiltren. Ytterligare studier krävs dock för att med säkerhet kunna bestämma den mest optimala placeringen.   Sammanfattningsvis visar resultaten från experimenten lovande tecken på att en ultrafiltreringsprocess är ett möjligt alternativ för att öka Norrvattens dricksvattenreningsverks effektivitet och kapacitet. / Norrvatten is the fourth largest drinking water producer in Sweden. They produce and distribute drinking water to 14 municipalities north of Stockholm. For some time, Norrvatten has studied alternative processes in order to optimise and increase the production capacity and efficiency of their drinking water treatment plant at Görvälnverket.   In this project, a small-scale pilot plant has been used to study and optimise a coagulation and ultrafiltration hybrid process step in order to remove humic substances from surface water. The effect of pH, reaction time, and different feed water qualities (Görväln, Fyrisån and Görväln full scale sand filtrate) were analysed through a series of experiments performed with the pilot plant. The most optimal placement of an eventual ultrafiltration step was also studied.  The results from the experiments suggested that pH in the range 6.1 to 6.7 had no large effect on the removal efficiency of fluorescent dissolved organic matter (fDOM). Instead, differences in removal efficiency could be observed between coagulant dosages which indicates that this parameter is of more importance than pH. At higher pH (&gt; 7) removal was significantly lower. The reaction time had no effect on the removal efficiency of the plant. However, the transmembrane pressure increased ten times faster during the experiments with a shorter reaction time. These results suggested that the floc formed were smaller and thereby more tightly packed in the ultrafilter which in turn increased the pressure in the membrane. An fDOM removal of at least 50 %, though no more than 60 %, was achieved with all feed waters except for the sand filtrate which had a removal efficiency of 18 %. However, highly concentrated humic waters such as Fyrisån proved to be challenging for the plant to handle since the pressure built up rather quickly in the membrane. The sand filtrate feed water experiments indicated that an ultrafiltration step after a sand filtration process would be effective. However, further studies are required to be able to determine the most optimal placement of the ultrafiltration process.  In conclusion, the results achieved with the pilot plant show promising signs of an ultrafiltration process being a viable alternative for Norrvatten to increase their drinking water treatment plant’s efficiency and capacity.

L'objectif de cette recherche est de définir les significations du N (nom) fois au travers des principales constructions qui l'utilisent en français contemporain, et d‟expliquer la formation des expressions dérivées autrefois, des fois (que), parfois, quelquefois, toutefois, une fois (que). Examiné sous l'angle du lexique, le mot fois est un substantif féminin, qui, précédé d'un déterminant, se constitue en groupe nominal (GN). Le N fois dénote un comptage d'occurrences, c'est-à-dire d'unités de discours, qui sont le plus souvent des processus verbaux ou des prédicats. Il s'agit donc d‟unités linguistiques ce qui explique que fois apparaît dans des contextes divers. Nous avons classé les principales constructions en fonction des déterminants relevés dans le GN fois. D'une part, les GN composés des adjectifs cardinaux ou quantificateurs + fois permettent de compter des occurrences du langage et ont une fonction adverbiale de quantification ; si les occurrences comptées sont des processus verbaux, ils portent en sus une notion temporelle à valeur itérative ou fréquentielle. Avec les autres déterminants (article défini et indéfini, adjectif démonstratif, quantificateurs universels tous les et chaque), fois est un nom temporel qui tend à se standardiser. Les expressions dérivées évoluent sémantiquement et produisent une forme adverbiale préalable à d'autres transformations. Nous pouvons ainsi identifier le groupe des adverbiaux de quantification, le plus ancien, qui a facilité l'apparition des expressions dérivées, et un groupe plus récent où fois apparaît comme un nom temporel au même titre que jour, instant ou moment.