| 1. |
- Baresel, Christian, et al.
(författare)
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Rening av hormoner vid avloppsreningsverk i kalla klimat : En kunskapssammanställning och lärdomar från pilottester vid Fillan ARV i Sundsvall
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Vid tre av de största avloppsreningsverken i Sundsvall kommun har IVL genomfört en förstudie med syftet att utreda förutsättningar för en fullskaleinstallation för rening av läkemedelsrester från avloppsvatten. Förstudien visade att det framför allt var hormoner som utgjorde den största risken för negativ påverkan på vattenförekomsten. Eftersom Sundsvall kommun har planer för en framtida utbyggnad med kväverening vid Fillan ARV, föddes en tanke om huruvida en sådan utbyggnad även skulle kunna bidra till att hormonhalterna i utgående avloppsvatten minskar till icke-detekterbara nivåer.Detta mot bakgrund av att minskade hormonhalter observerats vid avloppsreningsverk med kväverening i södra Sverige. Om motsvarande minskning av utgående hormonhalter skulle observeras vid en utbyggd kväverening i Sundsvall kommun, skulle detta leda till att de observerade miljöriskerna i recipienten eliminerades.Med ekonomiskt stöd från Naturvårdsverket, och med hjälp av en befintlig pilotanläggning för studier av kväverening i kalla klimat via rörliga biofilmsreaktorer med bärare (MBBR), genomfördes under åren 2021 och 2023 en kompletterande förstudie vars resultat presenteras i denna rapport. Projektet har fokuserat på rening av hormoner och hormonstörande effekter vid implementering av kväverening i kalla klimat. Det övergripande målet har varit att öka kunskapen om kväverening och nedbrytning av hormoner vid låga temperaturer och att identifiera kunskapsluckor.Denna kunskap ska stödja planering och implementering av reningsprocesser vid höga hormonhalter i avloppsvatten i kalla klimat.Föreliggande rapport sammanställer dels kunskap om rening av hormoner och hormonstörande ämnen vid avloppsreningsverk utifrån i huvudsak en svensk kontext, dels resultat från genomförda pilottester vid Fillan ARV i Sundsvall. Genomgående under projektperioden observerades att kväve kunde reduceras med mer än 70 % i genomsnitt. Veckovisa analyser av hormoner och hormonstörande effekter, samt månadsvisa analyser av läkemedelsrester, visade däremot på en stor variation av inkommande halter och reningrader.En genomgående, och förväntad trend, var att halterna av östrogena effekter följde detekterade halter av både östron och östradiol. Halten av etinylöstradiol, däremot, detekterades inte i något av de analyserade proverna under hela projektperioden. Vid de tillfällen där reduktionsgraden av hormonerna var närmare 80 %, var det fortfarande höga halter av hormoner i utgående avloppsvatten, vilket bland annat kunde förklaras med höga inkommande halter. Inga tydliga samband mellan höga reduktionshalter av hormoner och kväve eller andra processrelaterade aspekter kunde observeras. Detta resultat indikerar att reduktion av hormoner och kväverening i huvudsak utförs av skilda grupper av mikroorganismer. En högre reduktion av hormoner kunde däremot observeras i filtrerade prover relativt ofiltrerade, något som delvis kan förklara den låga hormonreduktion efter MBBR-processen som vid dessa försök saknade en partikelavskiljning. Sammanfattningsvis kan det konstateras att hypotesen kring att kväverening effektivt kan rena bort hormoner i kalla klimat med en MBBR-teknik inte kan bekräftas vid de betingelser som utvärderats i denna rapport. Det kunde inte heller bekräftas när temperaturen ökade med 4 °C i processen eftersom ingen signifikant påverkan på reningsgraden för varken hormoner, hormonstörande effekter eller läkemedelsrester kunde observeras. Utifrån data från denna rapport kan det därför konstateras att vid anläggningar i norra Sverige, där höga hormonhalter utgör huvudproblemet avseende påverkan på recipient, kan en avancerad rening för att ta bort hormoner och deras effekter behövas, åtminstone i de fall där biofilmsprocesser såsom MBBR implementeras.
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| 2. |
- Kumar, Sudesh, et al.
(författare)
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Reversible in situ precipitation: a flow-through approach for coating macroporous supports with metal hydroxides
- 2014
-
Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488. ; 2:4, s. 1076-1084
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Tidskriftsartikel (refereegranskat)abstract
- In this study we report on the production of metal-hydroxide-coated macroporous polymers (MHCMPs), which mainly involves a polyacrylamide backbone coated with iron-aluminium double hydroxides. The coating process is fast, occurs using relatively mild reagents at room temperature, and can be repeated multiple times, thus making it a very simple and flexible process. Electron microscopy and energy dispersive X-ray spectroscopy studies showed that metal hydroxide coating occurred throughout the polymer backbone. It was shown that the mass of metal hydroxides incorporated in the MHCMPs could be adjusted by varying the initial salt solution concentration or the number of cycles in the process. Under the studied conditions, on a polymer backbone of mass 25 mg, we observed a maximum metal hydroxide mass incorporation of 18 mg for the MHCMPs produced at 6 cycles by using 0.4 M iron and aluminium salt solution. Nitrogen adsorption isotherms indicated that the surface area of the MHCMPs increased linearly with the increase in the mass of metal hydroxides incorporated. The polymer backbone with no mass incorporated showed a BET surface area of 18 m(2) g(-1) and the MHCMPs with maximum mass incorporation under the studied conditions showed a BET surface area of 63 m(2) g(-1). MHCMPs with varying mass incorporations were applied for arsenic (As(III)) adsorption and showed a high As(III) removal, indicating that they can serve as potential adsorbents. In addition, MHCMPs incorporated with other metal hydroxides were also produced and characterized to show that this method is applicable for coating these as well.
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| 3. |
- Moshi, Anselm, et al.
(författare)
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Production of raw starch-degrading enzyme by Aspergillus sp. and its use in conversion of inedible wild cassava flour to bioethanol.
- 2015
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Ingår i: Journal of Bioscience and Bioengineering. - : Elsevier BV. - 1347-4421 .- 1389-1723.
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Tidskriftsartikel (refereegranskat)abstract
- The major bottlenecks in achieving competitive bioethanol fuel are the high cost of feedstock, energy and enzymes employed in pretreatment prior to fermentation. Lignocellulosic biomass has been proposed as an alternative feedstock, but because of its complexity, economic viability is yet to be realized. Therefore, research around non-conventional feedstocks and deployment of bioconversion approaches that downsize the cost of energy and enzymes is justified. In this study, a non-conventional feedstock, inedible wild cassava was used for bioethanol production. Bioconversion of raw starch from the wild cassava to bioethanol at low temperature was investigated using both a co-culture of Aspergillus sp. and Saccharomyces cerevisiae, and a monoculture of the later with enzyme preparation from the former. A newly isolated strain of Aspergillus sp. MZA-3 produced raw starch-degrading enzyme which displayed highest activity of 3.3 U/mL towards raw starch from wild cassava at 50°C, pH 5.5. A co-culture of MZA-3 and S. cerevisiae; and a monoculture of S. cerevisiae and MZA-3 enzyme (both supplemented with glucoamylase) resulted into bioethanol yield (percentage of the theoretical yield) of 91 and 95 at efficiency (percentage) of 84 and 96, respectively. Direct bioconversion of raw starch to bioethanol was achieved at 30°C through the co-culture approach. This could be attractive since it may significantly downsize energy expenses.
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| 4. |
- Paul, Catherine, et al.
(författare)
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A GH57 4-α-glucanotransferase of hyperthermophilic origin with potential for alkyl glycoside production.
- 2015
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Ingår i: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 1432-0614 .- 0175-7598. ; 99:17, s. 7101-7113
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Tidskriftsartikel (refereegranskat)abstract
- 4-α-Glucanotransferase (GTase) enzymes (EC 2.4.1.25) modulate the size of α-glucans by cleaving and reforming α-1,4 glycosidic bonds in α-glucans, an essential process in starch and glycogen metabolism in plants and microorganisms. The glycoside hydrolase family 57 enzyme (GTase57) studied in the current work catalyzes both disproportionation and cyclization reactions. Amylose was converted into cyclic amylose (with a minimum size of 17 glucose monomers) as well as to a spectrum of maltodextrins, but in contrast to glycoside hydrolase family 13 cyclodextrin glucanotransferases (CGTases), no production of cyclodextrins (C6-C8) was observed. GTase57 also effectively produced alkyl-glycosides with long α-glucan chains from dodecyl-β-D-maltoside and starch, demonstrating the potential of the enzyme to produce novel variants of surfactants. Importantly, the GTase57 has excellent thermostability with a maximal activity at 95 °C and an activity half-life of 150 min at 90 °C which is highly advantageous in this manufacturing process suggesting that enzymes from this relatively uncharacterized family, GH57, can be powerful biocatalysts for the production of large head group glucosides from soluble starch.
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| 5. |
- Quiroga Flores, Roxana, et al.
(författare)
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Adsorption of cadmium by a high-capacity adsorbent composed of silicate-titanate nanotubes embedded in hydrogel chitosan beads
- 2020
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Ingår i: Environmental Technology. - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 41:23, s. 3043-3054
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we developed a nanoparticle-based mesoporous composite that consisted of silicate-titanate nanotubes (STNTs) supported in hydrogel chitosan beads (STNTs-Ch beads) and was studied for Cd2+ adsorption. By using Fourier-transform infrared spectroscopy, transmission and scanning electron microscopy coupled to an energy-dispersive X-ray spectrometer, we coulddetermine that the hollow STNTs were highly dispersed in the walls of the hollow beads. The dispersion was attributed to the effect of pH when the composite was prepared and we observed a non-interaction between STNTs and chitosan. The adsorption studies of Cd2+ showed that the kinetic rate (k2) increased 3-fold and that the diffusion rate (Kd) increased 2-fold afterthe embedment. Moreover, the maximum capacity of adsorption of STNTs-Ch beads was 2.3 times higher than that of STNTs alone. The treatment of a synthetic Cd2+ solution and a real leachate in continuous mode showed two phases in which it was observed higher removed fractions of transition metal ions (Cd2+, Co2+, Ni2+, Zn2+ and Cu2+) and the post-transition metal ion Pb2+, in comparison to the removed fractions of alkali and alkali-earth metal ions (Ca2+, K+, Mg2+). The composite was successfully reused four times when adsorbing Cd2+, saving three times the needed amounts of TiO2, SiO2 and chitosan for the production of the material. This composite was produced in a simple way and shows the potential for wastewater treatment.
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| 6. |
- Suresh, Prashanth, et al.
(författare)
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Arsenic adsorption by iron-aluminium hydroxide coated onto macroporous supports : Insights from X-ray absorption spectroscopy and comparison with granular ferric hydroxides
- 2016
-
Ingår i: Journal of Hazardous Materials. - : Elsevier. - 0304-3894 .- 1873-3336. ; 302, s. 166-174
-
Tidskriftsartikel (refereegranskat)abstract
- This paper evaluates the arsenic adsorption characteristics of a macroporous polymer coated with coprecipitated iron-aluminium hydroxides (MHCMP). The MHCMP adsorbent-composite fits best with a pseudo-second order model for As(III) and a pseudo-first order kinetic model for As(V). The MHCMP shows a maximum adsorption capacity of 82.3 and 49.6 mgAs/g adsorbent for As(III) and As(V) ions respectively, and adsorption followed the Langmuir model. Extended X-ray absorption fine structure showed that binding of As(III) ions were confirmed to take place on the iron hydroxides coated on the MHCMP, whereas for As(V) ions the binding specificity could not be attributed to one particular metal hydroxide. As(III) formed a bidentate mononuclear complex with Fe sites, whereas As(V) indicated on a bidentate binuclear complex with Al sites or monodentate with Fe sites on the adsorbent. The column experiments were run in a well water spiked with a low concentration of As(III) (100 mu g/L) and a commercially available adsorbent (GEH (R) 102) based on granular iron-hydroxide was used for comparison. It was found that the MHCMP was able to treat 7 times more volume of well water as compared to GEH (R) 102, maintaining the threshold concentration of less than 10 mu gAs/L, indicating that the MHCMP is a superior adsorbent.
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| 7. |
- Suresh, Prashanth, et al.
(författare)
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Arsenite adsorption on cryogels embedded with iron-aluminium double hydrous oxides: Possible polishing step for smelting wastewater?
- 2013
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 1873-3336 .- 0304-3894. ; 250, s. 469-476
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Tidskriftsartikel (refereegranskat)abstract
- Arsenic is among the most toxic elements and it commonly exists in water as arsenite (As(III)) and arsenate (As(V)) ions. As(III) removal often requires a pre-oxidation or pH adjustment step and it is a challenge to adsorb As(III) at circumneutral pH. In this study, iron-aluminium double hydrous oxides were synthesized and incorporated into cryogels. The resulting composite cryogels were evaluated for As(III) adsorption. Initial experiments indicated that the adsorbent showed similar adsorption kinetics for both As(V) and As(III) ions. The adsorption of As(III) best fit the Langmuir isotherm and the maximum adsorption capacity was 24.6mg/g. Kinetic modeling indicated that the mechanism of adsorption was chemisorption, making the adsorbent-adsorbate interactions independent of charge and hence allowing the adsorbent to function equally efficient across pH 4-11. A Swedish smelting wastewater was used to evaluate the adsorption performance in continuous mode. The studies showed that the adsorbent was successful in reducing the arsenic concentrations below the European Union emission limit (0.15mg/l) in a smelting wastewater collected after two precipitation processes. The arsenic removal was obtained without requiring a pH adjustment or a pre-oxidation step, making it a potential choice as an adsorbent for As(III) removal from industrial wastewaters.
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| 8. |
- Önnby, Linda, et al.
(författare)
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Applications of Cryogels in Water and Wastewater Treatment
- 2016
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Ingår i: Supermacroporous Cryogels : Biomedical and Biotechnological Applications - Biomedical and Biotechnological Applications. - : CRC Press. - 9781482228823 ; , s. 331-364
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Bokkapitel (refereegranskat)abstract
- Cryogels have potential for applications in water and wastewater treatment. However, maximum levels of exposure to both incorporated materials in cryogels (i.e., nanoparticles [NPs]) and monomers, as a result of leakage, must be established before cryogel composites can be implemented in the large-scale treatment of water. Other factors, such as cost and reuse, must also be studied for each specific adsorbent. One of the greater advantages of cryogels is the flexibility of their preparation. The material can be prepared as monoliths, discs, beads or particles, to suit specific requirements. Results on a laboratory scale may be different from those obtained when treating real water and wastewater due to differences in scale and water chemistry. The social acceptance of the technology and its overall environmental impact must also be assessed. This chapter starts with describing how cryogel materials have been developed from their initial applications in water treatment to more recent developments. This is followed by current published results obtained from the treatment of water from different sources, including both lab-scale evaluations as well as real water samples. As the main application of cryogels within water treatment today is as adsorbent materials, these will be given the main focus for this chapter but still include more recent research results from applications regarding disinfection and oil absorption. The main pollutants of interest for this chapter are inorganic pollutants such as metals and metalloids (e.g. cadmium and arsenic), but organic contaminants are also mentioned. Future challenges in this area today, regarding cryogel applications, cover the need for system regeneration, the deposition of the pollutant and, finally, the total cost of the treatment.
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| 9. |
- Önnby, Linda, et al.
(författare)
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Cryogel-supported titanate nanotubes for waste treatment: Impact on methane production and bio-fertilizer quality.
- 2015
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 207, s. 58-66
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Tidskriftsartikel (refereegranskat)abstract
- By reducing the cadmium (Cd(2+)) content in biomass used for bio-based products such as biogas, a less toxic bio-based fertilizer can be obtained. In this work, we demonstrate how a macroporous polymer can support titanate nanotubes, and we take advantage of its known selective adsorption behavior towards Cd(2+) in an adsorption process from real nutrient-rich process water from hydrolysis of seaweed, a pollutant-rich biomass. We show that pretreatment steps involving alteration in area-to-volume ratio performed in aerated and acidic conditions release the most Cd(2+) from the solid material. By integrating an adsorption step between hydrolysis and the biomethane, we show that it was possible to obtain high Cd(2+) removal (ca. 94%) despite molar excess (between 100 and 500) of co-present ions (e.g., Mg(2+), Ca(2+), Na(+), K(+)) and with maintained total phosphorous content. The bio-methane potential did not significantly decrease as compared to a process without cadmium removal and the yielded bio-fertilizer followed Swedish guideline values. This study provides a sound and promising alternative for a novel remediation step, enabling higher use of otherwise tricky and to some extent overlooked biomass sources.
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| 10. |
- Önnby, Linda, et al.
(författare)
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Improved arsenic(III) adsorption by Al2O3 nanoparticles and H2O2: Evidence of oxidation to arsenic(V) from X-ray absorption spectroscopy.
- 2014
-
Ingår i: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 113, s. 151-157
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the oxidation of inorganic As(III) with H2O2 catalysed by Al2O3, using X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopy. The effects of different reaction conditions (pH, time and initial H2O2 concentration) were also studied as were the kinetics of the oxidation reaction. We demonstrated that As(III) was oxidized to As(V) in the presence of H2O2 and Al2O3. Furthermore, all arsenic species found on the Al2O3 surface were in the As(V) state. The presence of both Al2O3 and H2O2 was necessary for oxidation of As(III) to take place within the period of time studied. The oxidation kinetics indicate a mechanism where reversible As(III) binding to the alumina surface is followed by irreversible oxidation by H2O2 leading to strongly bound As(V). Results from this study indicate that there is a surface-catalysed oxidation of As(III) on Al2O3 by H2O2, a reaction that can take place in nature and can be of help in the development of novel treatment systems for As(III) removal.
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| 11. |
- Önnby, Linda, et al.
(författare)
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Kartläggning av organiska mikroföroreningar – Töreboda avloppsreningsverk : Kartläggning, miljöpåverkan och åtgärdsförslag
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Töreboda avloppsreningsverk (ARV) är ett mindre reningsverk i Västra Götaland som tar emot avloppsvatten från Töreboda tätort, en livsmedelsindustri samt en liten andel från en nedlagd deponi i kommunen. Reningsverkets recipient är Friaån. Tidigare undersökningar av vattenkvalitén i Friaån har vid ett provtillfälle indikerat höga koncentrationer av mikroföroreningarna diklofenak, östradiol och perfluorooktansyra (PFOS), som är ett vanligt förekommande ämne inom ämnesgruppen perfluorerade alkylsubstanser (PFAS). Någon detektion av etinylöstradiol, ett ämne som har stark östrogen effekt i den akvatiska miljön, gjordes inte, utan detta ämne rapporterades under rapporteringsgränsen.För de kvantifierade ämnena gällde särskilt att de påträffats vid halter som överstiger bedömningsgrunder för godkänd ekologisk status för inlandsytvatten enligt Havs- och vattenmyndighetens författningssamling. IVL Svenska Miljöinstitutet (IVL) har genomfört en kartläggning av mikroföroreningar för att bedöma risker och åtgärder som kan bli aktuellt för Töreboda ARV i framtiden avseende avancerad rening av mikroföroreningar såsom antibiotika, läkemedel och hormoner. Riskbedömningen utgår från hur ARV påverkar recipienten.Kartläggningen av mikroföroreningar har genomförts genom provtagning vid fyra tillfällen under ett års tid vid i) reningsverket och ii) i recipienten.Inkommande och utgående avloppsvatten vid reningsverket provtogs genom veckoprover. Recipientprover uppströms och nedströms reningsverkets utsläppspunkt togs som stickprover. Analyser inom projektet har avsett läkemedelsrester, hormoner, antibiotika, fenoler, östrogen effekt samt PFAS-ämnen. Utöver ARV och recipient, har analys av lakvattenprover också genomförts avseende PFAS ämnen, som ett led i att utvärdera påverkan från källor uppströms ARV. För att bedöma recipientpåverkan har två tillvägagångssätt använts. Dels har recipienthalten predikterats genom en beräknad utspädning av halten i utgående avloppsvatten, dels har uppmätta halter i recipienten nyttjats. Beräkning av utspädningen i recipienten gjordes med hjälp av aktuellt flöde ut från ARV och aktuellt flöde i recipienten. Det senare erhölls genom att använda flödesdata från SMHI:s flödesmodell S-hype.Recipientbedömning har genomförts genom att beräkna riskkvoter (PEC/PNEC-kvoter där PEC står för predicted environmental concentration och PNEC står för predicted no effect concentration). När kvoten överskrider 1 indikeras att det föreligger en risk i recipienten.Kartläggningen av mikroföroreningar från Töreboda ARV samt upp- och nedströms i recipienten visade att halterna av mikroföroreningar, i tre fall av fyra, var högre nedströms jämfört med provpunkten uppströms reningsverkets utsläppspunkt. Halterna av PFAS-ämnen in och ut från reningsverket indikerade också att de låg relativt högt vid jämförelse med medelhalten för andra svenska reningsverk.Uppströmskällor till Töreboda ARV som kan bidra med PFAS-ämnen är den nedlagda deponin i Borreboda, som bidrar med lakvatten motsvarande ca 1 % av det årliga inflödet. PFAS-belastningen från lakvattnet visade sig motsvara ca 12,1 % av den totala årsbelastningen in till reningsverket.Recipientbedömningen indikerade att det råder hög miljörisk för sex mikroföroreningar nedströms recipienten, inklusive PFOS och diklofenak som det finns nationella bedömningsgrunder för god status för. PFOS återfanns dock både upp- och nedströms Töreboda ARV och det finns därmed uppströms källor för denna förekomst. Sammantaget, och sett till aktuella bedömningsgrunder, kan det därmed inte uteslutas att det finns ett behov av avancerad rening vid Töreboda ARV. PFOS-förekomsten bör dock åtgärdas vid källan och inte primärt vid Töreboda ARV. När förslaget till nytt EQS-direktiv beaktas utgör även bisfenol A en risk för recipienten, samt PFAS24, uttryckt som PFOA-ekvivalenter, vilka observeras med hög risk både upp- och nedströms Töreboda ARV. Även diklofenak tillkommer som ett ämne som utgör hög risk eftersom det befintliga gränsvärdet föreslås att sänkas i nya EQS direktivet.Sett till befintliga och möjliga tekniker för Töreboda ARV fungerar både i) ozon efterföljt av efterbehandling i form av exempelvis GAK-filtrering, och ii) GAK som ett ensamt reningssteg. GAK står för Granulerat Aktivt Kol. För ozon är det ämnet oxazepam som kan verka begränsande och särskilt vid så låg utspädning som fem eller lägre. I detta fall resulterar det i att ozondosen behöver ligga inom intervallet 0,7 - 1,0 mg ozon/mg DOC. För GAK är det ämnena diklofenak, oxazepam och furosemid som kan verka begränsande vid låg utspädning i förhållande till högflöde, och eventuellt resultera i att ett filterbyte sker tidigare än 20 000 bäddvolymer. Avseende PFOS gäller för båda teknikerna att det är begränsande vid låg utspädning. Detta ämne, och PFAS11 i sin helhet, bör dock åtgärdas uppströms och därför har inget större fokus ägnats åt PFOS-åtgärd vid reningsverket. Ett avancerat reningssteg föreslås placeras sist i den befintliga reningsprocessen och kan med fördel föregås av ett filtersteg såsom sandfilter och/eller mikrosil för att minska risken för att partiklar går in i det avancerade reningssteget.Om ozon efterföljs av GAK-filtrering kan fler mikroföroreningar avskiljas jämfört med när ozon efterföljs av sandfilter. Det behövs ca fyra GAK-filter om de dimensioneras med en volym på 50 m3 och årligen uppskattas det att ca 52 ton aktivt kol förbrukas.Framgent rekommenderas Töreboda ARV att genomföra en teknikutredning för att i detalj förstå teknikernas kostnad, möjlighet och eventuella miljövinst. PFAS källor uppströms reningsverket bör också utredas. Det kan även vara av vikt att förstå hur reningsverkets flöde påverkar recipientflödet över ett helt år, när det både råder låg- respektive högflöde
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| 12. |
- Önnby, Linda, et al.
(författare)
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Polymer composite adsorbents using particles of molecularly imprinted polymers or aluminium oxide nanoparticles for treatment of arsenic contaminated waters.
- 2012
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Ingår i: Water Research. - : Elsevier BV. - 1879-2448 .- 0043-1354. ; 46:13, s. 4111-4120
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Tidskriftsartikel (refereegranskat)abstract
- Removal of As(V) by adsorption from water solutions was studied using three different synthetic adsorbents. The adsorbents, (a) aluminium nanoparticles (Alu-NPs, <50 nm) incorporated in amine rich cryogels (Alu-cryo), (b) molecular imprinted polymers (<38 μm) in polyacrylamide cryogels (MIP-cryo) and (c) thiol functionalised cryogels (SH-cryo) were evaluated regarding material characteristics and arsenic removal in batch test and continuous mode. Results revealed that a composite design with particles incorporated in cryogels was a successful means for applying small particles (nano- and micro- scale) in water solutions with maintained adsorption capacity and kinetics. Low capacity was obtained from SH-cryo and this adsorbent was hence excluded from the study. The adsorption capacities for the composites were 20.3 ± 0.8 mg/g adsorbent (Alu-cryo) and 7.9 ± 0.7 mg/g adsorbent (MIP-cryo) respectively. From SEM images it was seen that particles were homogeneously distributed in Alu-cryo and heterogeneously distributed in MIP-cryo. The particle incorporation increased the mechanical stability and the polymer backbones of pure polyacrylamide (MIP-cryo) were of better stability than the amine containing polymer backbone (Alu-cryo). Both composites worked well in the studied pH range of pH 2-8. Adsorption tested in real wastewater spiked with arsenic showed that co-ions (nitrate, sulphate and phosphate) affected arsenic removal for Alu-cryo more than for MIP-cryo. Both composites still adsorbed well in the presence of counter-ions (copper and zinc) present at low concentrations (μg/l). The unchanged and selective adsorption in realistic water observed for MIP-cryo was concluded to be due to a successful imprinting, here controlled using a non-imprinted polymer (NIP). A development of MIP-cryo is needed, considering its low adsorption capacity.
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| 13. |
- Önnby, Linda, et al.
(författare)
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Removal of heavy metals from water effluents using supermacroporous metal chelating cryogels.
- 2010
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Ingår i: Biotechnology Progress. - : Wiley. - 1520-6033 .- 8756-7938. ; 26:5, s. 1295-1302
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Tidskriftsartikel (refereegranskat)abstract
- Applications of IDA in, for example, immobilized metal ion affinity chromatography for purification of His-tagged proteins are well recognized. The use of IDA as an efficient chelating adsorbent for environmental separations, that is, for the capture of heavy metals, is not studied. Adsorbents based on supermacroporous gels (cryogels) bearing metal chelating functionalities (IDA residues and ligand derived from derivatization of epoxy-cryogel with tris(2-aminoethyl)amine followed by the treatment with bromoacetic acid (defined as TBA ligand)) have been prepared and evaluated on capture of heavy metal ions. The cryogels were prepared in plastic carriers, resulting in desired mechanical stability and named as macroporous gel particles (MGPs). Sorption and desorption experiments for different metals (Cu²+, Zn²+, Cd²+, and Ni²+ with IDA adsorbent and Cu²+ and Zn²+ with TBA adsorbent) were carried out in batch and monolithic modes, respectively. Obtained capacities with Cu²+ were 74 μmol/mL (TBA) and 19 μmol/mL gel (IDA). The metal removal was higher for pH values between pH 3 and 5. Both adsorbents showed improved sorption at lower temperatures (10°C) than at higher (40°C) and the adsorption significantly dropped for the TBA adsorbent and Zn²+ at 40°C. Desorption of Cu²+ by using 1 M HCl and 0.1 M EDTA was successful for the IDA adsorbent whereas the desorption with the TBA adsorbent needs further attention. The result of this work has demonstrated that MGPs are potential treatment alternatives within the field of environmental separations and the removal of heavy metals from water effluents.
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| 14. |
- Önnby, Linda
(författare)
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Water treatment using cryogel-based adsorbents - Targeting environmental pollutants at low concentrations
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The lack of safe, clean water is strongly linked to poverty, underdevelopment and poor health. Water is needed not only to sustain life, but to produce food and in industrial processes. Anthropogenic pollution and natural events can jeopardize access to safe water. Inorganic pollutants or toxic metal ions such as arsenic and cadmium are of special concern since these are persistent and accumulate in nature. Contaminated water used for direct consumption or for irrigation of crops can thus lead to direct and indirect exposure to humans to these metals. To improve access to safe water, treatment must be developed to remove even low concentrations of toxic metal ions. Adsorption is a suitable technique. In this work, adsorbents were developed for various kinds of water sources; dinking water, wastewater, industrial water and leachate from a biogas process, all of which contained metal ions, such as As or Cd, at low concentrations. The adsorbents developed were based on a polymer cryogels, produced via cryoconcentration. Cryogels have a highly interconnected and porous structure, making them suitable for water treatment. The cryogels evaluated in this thesis were all based on the polymer polyacrylamide (pAAm). In the first study, a pAAm cryogel was chemically modified with chelating functionalities suitable for the removal of heavy metals (i.e. Cu2+, Zn2+, Pb2+ and Ni2). A rational design was suggested, involving preparation of the polymer inside plastic carriers to increase the mechanical stability of the material. Another strategy using particles was explored by embedding either nanoparticles (NPs) or molecularly imprinted polymers (MIPs) in pAAm-cryogels. The ability of Al2O3 NPs or MIPs in cryogels (called Alu-cryo and MIP-cryo, respectively), to remove As(V) was investigated. Both Alu-cryo and MIP-cryo exhibited adsorption capacities similar to those when the respective particles were applied in suspension. MIP-cryo showed higher selectivity but lower adsorption capacity than Alu-cryo. To improve the removal of As(III) without any pretreatment, co-precipitated Fe-Al hydrous oxides were prepared and embedded in cryogels. As(III) could be removed from smelting wastewater in flow-through mode, reducing the concentration to European industrial emission standards. The removal of Cd2+ from leachate resulting from the anaerobic digestion of seaweed was studied using hydrothermally modified TiO2 embedded in cryogels. This cryogel was shown to be successful in removing Cd2+ when tested in flow-through mode, and high adsorption capacities were obtained. Toxicity and particle leakage were studied in NP-embedded cryogels. Although no evidence of particle leaking was found, toxicity resulted from the leakage of the monomer acrylamide from the cryogel. The findings of this work show that cryogel-based adsorbents have potential in water treatment, due to their broad range of applications and the flexibility of the material. New and improved methods of particle immobilization in cryogels should be investigated, and pAAm should be replaced by non-toxic alternatives. Making cryogel materials with high adsorption capacities, which can be regenerated, can reduce the cost of water treatment. It is also important that novel technology meets environmental safety requirements to ensure the supply of safe water.
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| 15. |
- Önnby, Linda, et al.
(författare)
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γ-Al2O3-based nanocomposite adsorbents for arsenic(V) removal: Assessing performance, toxicity and particle leakage.
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 473, s. 207-214
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Tidskriftsartikel (refereegranskat)abstract
- The generation and development of effective adsorption materials for arsenic removal are urgently needed due to acute arsenic contamination of water sources in many regions around the world. In the search for these new adsorbents, the application of nanomaterials or nanocomposites, and especially the use of nanoparticles (NPs), has proven increasingly attractive. While the adsorptive performance of a range of nanocomposite and nanomaterial-based systems has been extensively reviewed in previously-published literature, the stability of these systems in terms of NP release, i.e. the ability of the nanomaterial or nanocomposite to retain incorporated NPs, is less well understood. Here we examine the performance of nanocomposites comprised of aluminium oxide nanoparticles (AluNPs) incorporated in macroporous polyacrylamide-based cryogels (n-Alu-cryo, where n indicates the percentage of AluNPs in the polymer material (n=0-6%, w/v)) for As(V) adsorption, and evaluate AluNP leakage before and after the use of these materials. A range of techniques is utilised and assessed (SEM, TEM, mass weight change, PIXE and in vitro toxicity studies). The 4-Alu-cryo nanocomposite was shown to be optimal for minimising AluNP losses while maximising As(V) removal. From the same nanocomposite we were further able to show that NP losses were not detectable at the AluNP concentrations used in the study. Toxicity tests revealed that no cytotoxic effects could be observed. The cryogel-AluNPs composites were not only effective in As(V) removal but also in immobilising the AluNPs. More challenging flow-through conditions for the evaluation of NP leakage could be included as a next step in a continued study assessing particle loss and subsequent toxicity.
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