Browsing by Author "Mergen, Maxime Rodolphe Denis"

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    Impact of magnetic resin on DOC removal and downstream water treatment processes
    (Cranfield University, 2008-01) Mergen, Maxime Rodolphe Denis; Parsons, Simon; Jarvis, Peter; Jefferson, Bruce
    Seasonal periods of high rainfall and changes in land management have led to difficulties for UK water companies to remove sufficient natural organic matter (NOM) to stay in compliance with the tightening trihalomethane (THMs) standards. Hence alternative treatment options have come into focus of research and development. The continuous anion exchange process based on a novel magnetic resin (MIEX® resin) has emerged as a promising method to increase NOM removal and has been compared in this thesis to the most widely spread drinking water treatment method of coagulation with hydrolysing metal salts. Therefore the removal efficiency of both processes was investigated by treating different natural waters sources as well as selected organic model compounds of different hydrophobicity and molecular weight (MW). Magnetic resin was thereby seen to be competitive with coagulation for DOC removal in low SUVA sources dominated by mid to low MW material and to outperform coagulation for the treatment of low MW, hydrophilic acids. However magnetic resin had to be used in combination with subsequent coagulation using largely reduced Fe doses to ensure high levels of DOC removal in sources dominated by high MW NOM. This was related to a physical blockage mechanism of the easily accessible external resin bead surface by this high MW material. An effect that could be reduced by applying increased resin doses, which provided a larger external surface area for DOC removal. A combination of magnetic resin treatment with coagulation was nonetheless seen to be able to increase DOC removal as well as to generate enhanced floc properties in terms of strength, settling velocity and size. Beside a reduced THM formation potential, making magnetic resin an effective tool to help meet legislative standards, an increased solid-liquid separation was seen in pilot-scale to result from these effects.
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    Magnetic ion-exchange resin treatment: Impact of water type and resin use
    (Elsevier Science B.V., Amsterdam., 2008-04-30T00:00:00Z) Mergen, Maxime Rodolphe Denis; Jefferson, Bruce; Parsons, Simon A.; Jarvis, Peter
    Three raw waters of fundamentally different natural organic matter (NOM) character were treated by magnetic resin using a bench-scale method designed to mimic how the resin is used in continuous operation. Increasing water hydrophobicity resulted in reduced dissolved organic carbon (DOC) removal with removal of 56%, 33% and 25% for waters containing 21%, 50% and 75% hydrophobic NOM, respectively. Study of consecutive resin uses showed that the NOM in the hydrophobic water had high affinity for the resin shown by DOC removal of 65% after the first use of the resin. This dropped to 25% DOC removal after 15 consecutive resin uses. For the more hydrophilic waters, NOM removal remained consistent after each resin use. The hydrophobic sample contained higher MW NOM that was capable of blocking resin sites that prevented continual adsorption of organics on to the resin. The hydrophilic NOM containing a large proportion of hydrophilic acids was consistently removed to around 60%. The water containing algogenic-derived NOM was poorly removed by magnetic resin. Subsequent coagulation showed higher removal with increasing hydrophobicity. (C) 2007 Elsevier Ltd, All rights reserved.