Seawater Desalination : A case study of coastal water supply options

Rapporten ämnar undersöka hur avsaltning av havsvatten används för att trygga dricksvattenförsörjningen i Värmdö respektive Östhammar kommun. Vidare behandlas även de juridiska aspekterna kring ämnet på såväl kommunal som nationell nivå. Arbetet avser även att utreda vilka risker som finns med att använda avsaltningsanläggningar för såväl konsumenterna av det avsaltade vattnet som för närliggande marina miljöer. För att besvara frågeställningarna genomfördes en fallstudie över de två kommunerna. Undersökningen baseras främst på litteraturstudier som kompletterats med intervjuer och studiebesök. Genom studien har det kunnat fastställas att avsaltning sker i de båda kommunerna, men i vilken omfattning detta sker har inte varit möjligt att besvara, vilket främst beror på att mindre avsaltningsanläggningar inte omfattas av tillståndsplikt. Således finns inget register över antalet anläggningar inom kommunerna, vilket ytterligare försvårade kartläggningen. Överlag finns inget sammanhängande regelverk för avsaltning samt att flera aktörer är inblandade i regleringen, vilket ytterligare kan försvåra kartläggning samt inkorporering av metoden för vattenförsörjning. Gällande påverkan på marina miljöer sågs brinet som den primära riskkällan, medan hälsoriskerna med att konsumera avsaltat vatten är omdiskuterat. Det fanns även få studier ämnade åt de svenska förutsättningar, därav rekommenderas ytterligare studier på området. Slutligen rekommenderas ökad samverkan mellan kommuner samt resurseffektivisering av vattenförsörjningen ifall avsaltning bedöms som olämplig inom kommunerna.The purpose of this report is to investigate if an expansion of desalination plants in Sweden could secure and amplify fresh water resources. The use of desalinated water in Sweden is currently not that widespread and there are few studies on how such expansion could impact the Swedish environment. The report aims to further investigate various health risks of consuming desalinated water and whether algae toxins from the Baltic Sea could be a potential health threat. To answer these questions a case study was conducted on the Värmdö municipality and Östhammar municipality, two archipelago municipalities located on the East coast of Sweden in Stockholm County respectively Uppsala County. Interviews with employees in both municipalities were conducted and supplemented with more interviews of other people active in the field. One of the main reasons for the interviews with employees in both municipalities was to answer the questions of how fresh water supply could be secured in the future if desalination plants were not a suitable option. Although the report was primarily based on a literature study, it was further complemented by two field excursions where two desalination plants were studied. The result of the study was that it was not possible to execute a detailed mapping of the number of desalination plants and how widespread desalination was in the municipalities, due to the fact the smaller facilities were excluded from permit obligation. A thorough mapping was likewise seen as expensive and time consuming which, if conducted by the municipalities, would require a redistribution of financial resources. The municipalities' attitude to desalination was positive, but it was not currently used in their fresh water supply. However there is currently no cohesive regulatory framework for desalination, and there is likewise a lack of a single authority with primary responsibility for desalination, which could aggravate implementation of desalination in Sweden. Consequently expanded cooperation between nearby municipalities as well as more resource efficient methods were proposed as solutions if desalination was unsuitable. The health risks of consuming desaline water was very oxymoronic; some sources said the lack of minerals in the water could result in cardiovascular diseases and other health issues, whereas other sources argued that they were due to different lifestyles. In addition algae toxins are common in the Baltic Sea which likewise could be a health risk. Overallt more research on the health risk of consuming desaline water is recommended since there are few studies on Swedish prerequisites. The main environmental impacts were the residual product from desalination, namely brine. The conclusion was that brine in low amounts probably did not pose a threat to the marine ecosystems and thus the environment, but again further studies are recommended