Avskiljning av uran från dricksvatten med reaktiva filter
Water is our most important provision and its quality is above all dependent on the geological conditions in the area from where it is extracted. Due to geological properties there are certain areas with an elevated risk of high uranium levels in the ground water, which in turn constitutes a risk...
| Main Author: | |
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| Format: | Otro |
| Language: | Swedish Swedish |
| Published: |
2008
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| Subjects: | |
| Online Access: | https://stud.epsilon.slu.se/11780/ |
| _version_ | 1855571937809399808 |
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| author | Dässman, Ellinor |
| author_browse | Dässman, Ellinor |
| author_facet | Dässman, Ellinor |
| author_sort | Dässman, Ellinor |
| collection | Epsilon Archive for Student Projects |
| description | Water is our most important provision and its quality is above all dependent on the
geological conditions in the area from where it is extracted. Due to geological
properties there are certain areas with an elevated risk of high uranium levels in the
ground water, which in turn constitutes a risk for human health. Consumption of water
that contains a high concentration of uranium implies a health risk due to the chemical
characteristics of uranium. Livsmedelsverket (The National Food Administration) and
Socialstyrelsen (The National Board of Health and Welfare) therefore recommend that
precautionary measures should be taken when the uranium concentration in ground
water exceeds 15 micrograms per litre. In particular, drinking water collected from
wells in areas with uranium-rich bedrock may have a harmfully high level of uranium.
One of the wells of the Ärla water purification plant, located near Eskilstuna, Sweden,
contains water that exceeds the guideline of 15 micrograms per litre.
One interesting technique for removing uranium from drinking water is adsorption to
reactive filter materials. Reactive filters represent a kind of low-cost technology that is intended to utilise a minimum of energy and chemicals. The filters may have specific
physical and chemical properties that make them suitable for removing unwanted
substances from the water. The aim of this thesis was to investigate the potential of
two different reactive filters for uranium removal, i.e. iron-oxide-coated olivine
(IOCO) and an anion exchange resin (Purolite).
The study included batch experiments with artificial water, from the Ärla water
purification plant, and water from a stream near the Stripa mine, both sites having
uranium levels higher than 15 micrograms per litre. The results that were obtained by
using iron oxide coated olivine filters were further analysed using the chemical
equilibrium model Visual Minteq 2.52. The model used was then optimised for
uranium removal. The study also included a column experiment with the two filter
materials, using water from the Ärla water purification plant. The goal was to provide
a more realistic picture of how efficient the filters really were concerning uranium
removal.
Results from the batch and column experiments showed that the iron oxide coated
olivine filter efficiently removed uranium. The two filter columns showed different
results, but both of them were able to reduce the uranium concentration to less than 11
micrograms per litre, i.e. significantly lower than the guideline mentioned above. The
ion exchange did not work as planned as the filtering efficiency gradually declined
during the latter part of the experiment. Presumably this was due more to technical
problems than to chemical ones. It seems likely that channels may have formed in the
filter material, causing a lower uranium removal efficiency.
In conclusion, it can be established that iron oxide coated olivine is a potentially
interesting filter material for the removal of uranium from drinking water, but further
research and development is needed. |
| format | Otro |
| id | RepoSLU11780 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish swe |
| publishDate | 2008 |
| publishDateSort | 2008 |
| record_format | eprints |
| spelling | RepoSLU117802017-10-17T10:27:44Z https://stud.epsilon.slu.se/11780/ Avskiljning av uran från dricksvatten med reaktiva filter Dässman, Ellinor Dept. of Soil Sciences Water resources and management Water is our most important provision and its quality is above all dependent on the geological conditions in the area from where it is extracted. Due to geological properties there are certain areas with an elevated risk of high uranium levels in the ground water, which in turn constitutes a risk for human health. Consumption of water that contains a high concentration of uranium implies a health risk due to the chemical characteristics of uranium. Livsmedelsverket (The National Food Administration) and Socialstyrelsen (The National Board of Health and Welfare) therefore recommend that precautionary measures should be taken when the uranium concentration in ground water exceeds 15 micrograms per litre. In particular, drinking water collected from wells in areas with uranium-rich bedrock may have a harmfully high level of uranium. One of the wells of the Ärla water purification plant, located near Eskilstuna, Sweden, contains water that exceeds the guideline of 15 micrograms per litre. One interesting technique for removing uranium from drinking water is adsorption to reactive filter materials. Reactive filters represent a kind of low-cost technology that is intended to utilise a minimum of energy and chemicals. The filters may have specific physical and chemical properties that make them suitable for removing unwanted substances from the water. The aim of this thesis was to investigate the potential of two different reactive filters for uranium removal, i.e. iron-oxide-coated olivine (IOCO) and an anion exchange resin (Purolite). The study included batch experiments with artificial water, from the Ärla water purification plant, and water from a stream near the Stripa mine, both sites having uranium levels higher than 15 micrograms per litre. The results that were obtained by using iron oxide coated olivine filters were further analysed using the chemical equilibrium model Visual Minteq 2.52. The model used was then optimised for uranium removal. The study also included a column experiment with the two filter materials, using water from the Ärla water purification plant. The goal was to provide a more realistic picture of how efficient the filters really were concerning uranium removal. Results from the batch and column experiments showed that the iron oxide coated olivine filter efficiently removed uranium. The two filter columns showed different results, but both of them were able to reduce the uranium concentration to less than 11 micrograms per litre, i.e. significantly lower than the guideline mentioned above. The ion exchange did not work as planned as the filtering efficiency gradually declined during the latter part of the experiment. Presumably this was due more to technical problems than to chemical ones. It seems likely that channels may have formed in the filter material, causing a lower uranium removal efficiency. In conclusion, it can be established that iron oxide coated olivine is a potentially interesting filter material for the removal of uranium from drinking water, but further research and development is needed. Vatten är vårt viktigaste livsmedel och dess kvalitet är framförallt beroende av de geologiska förutsättningarna där det utvinns. På grund av geologiska omständigheter finns det i vissa områden en förhöjd risk för höga koncentrationer av uran i grundvattnet, vilket i sin tur utgör en risk för människors hälsa. Att dricka uranhaltigt vatten kan vara en hälsorisk på grund av uranets kemiska egenskaper. Livsmedelsverket och Socialstyrelsen rekommenderar därför att åtgärder vidtas när dricksvattnet innehåller en högre koncentration av uran än 15 mikrogram per liter. Kartläggningar gjorda av SSI och SGU visar att det är framförallt bergborrande brunnar i områden med en uranrik berggrund som kan innebära skadliga koncentrationer uran i dricksvatten. I samhället Ärla, utanför Eskilstuna, ligger Ärla vattenverk där man i en av vattenverkets brunnar har koncentrationer av löst uran som överstiger riktvärdet. En intressant teknik att utveckla för uranavskiljning i brunnar är adsorption till reaktiva filtermaterial. Ett syfte med reaktiva filter är att kunna avskilja ämnen genom att använda ett minimum av energi och kemikalier. Reaktiva filter måste ha specifika fysikalisk-kemiska egenskaper för att kunna avskilja oönskade ämnen i vatten. Examensarbetets övergripande syfte var att undersöka två reaktiva filters potential för uranavskiljning; en järnoxidtäckt olivinsand samt en anjonbytarmassa. Examensarbetet innefattade skakförsök med konstgjorda vatten, vatten från Ärla vattenverk i Eskilstuna och vatten från en bäck nära Stripa Gruva, samtliga med lösta urankoncentrationer högre än 15 μg/l. Resultaten från skakförsöken med järnoxidtäckt olivinsand som filtermaterial tolkades med hjälp av det kemiska jämviktsprogrammet Visual MINTEQ 2.52. Modellen optimerades darefter för uranavskiljning. Studien innefattade även kolonnförsök med de två reaktiva filtermaterialen för vattnet i Ärla, detta för att få en mer verklig bild av hur effektiva filtren är gällande uranavskiljning. Resultat från skak- och kolonnförsöken visade att den järnoxidtäckta olivinsanden avskiljde uran effektivt. Kolonnerna innehållande järnoxidtäckt olivinsand skiljde sig åt men båda förmådde reducera urankoncentrationerna till mindre än 11 μg/l, vilket är klart lägre än gränsvärdet på 15 μg/l. Jonbytarmassan fungerade inte som önskat då avskiljningseffektiviteten gradvis försämrades under den senare delen av försöket. Förmodligen var problemet mer tekniskt än kemiskt då det med stor sannolikhet hade bildats kanalgångar som förorsakade en sämre avskiljning. Sammanfattningsvis kan det konstateras att de resultat som erhållits i min studie visar att järnoxidtäckt olivinsand är potentiellt intressant som filtermaterial för avskiljning av uran i dricksvatten men att ytterligare forskning och utveckling krävs. 2008-09-30 Other NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/11780/1/dassman_e_171017.pdf Dässman, Ellinor, 2008. Avskiljning av uran från dricksvatten med reaktiva filter. UNSPECIFIED, Uppsala. Uppsala: (NL, NJ) > Dept. of Soil Sciences <https://stud.epsilon.slu.se/view/divisions/4023.html> urn:nbn:se:slu:epsilon-s-7909 swe |
| spellingShingle | Dept. of Soil Sciences Water resources and management Dässman, Ellinor Avskiljning av uran från dricksvatten med reaktiva filter |
| title | Avskiljning av uran från dricksvatten med reaktiva filter |
| title_full | Avskiljning av uran från dricksvatten med reaktiva filter |
| title_fullStr | Avskiljning av uran från dricksvatten med reaktiva filter |
| title_full_unstemmed | Avskiljning av uran från dricksvatten med reaktiva filter |
| title_short | Avskiljning av uran från dricksvatten med reaktiva filter |
| title_sort | avskiljning av uran från dricksvatten med reaktiva filter |
| topic | Dept. of Soil Sciences Water resources and management |
| url | https://stud.epsilon.slu.se/11780/ https://stud.epsilon.slu.se/11780/ |