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SOLVATTEN is a combined portable water treatment and solar water heater system that has been designed for use at the household level in the developing world. The device uses natural UV radiation to treat water, and units are capable of rendering highly contaminated water drinkable (as defined by the WHO safe drinking water standards.〔(Climate Solver: Solar safe water system )〕) in a few hours, provided there is sufficient sunlight. SOLVATTEN incorporates three water treatment processes: filtration, pasteurisation and UV sterilisation.〔Lundström, H. & Hagström, E. A field study in Kenya of insolation parameters to make water drinkable in the household water treatment unit SOLVATTEN. Uppsala University, Sweden ()〕 Under optimal conditions, the device can eliminate all pathogenic material in 10-litres of water within 2 hours,〔Jönsson, J., Wikman, A. & Wätthammar, T. (2011) Social Return on Investment, SROI, the value added for families before and after using Solvatten in the Bungoma district in Western Kenya. Swedish University of Agricultural Sciences (SLU), Uppsala ()〕 allowing for multiple batches of water to be treated in a given day. The device is typically used in situations where water resources are scarce and prone to contamination, but it has also been applied in disaster relief scenarios.〔(Solvatten use following Typhoon Yolanda (in Swedish) )〕 The device and its inventor, Petra Wadström, have both achieved recognition through a series of national and international awards. == Design and Usage == Each SOLVATTEN unit consists of two five-litre containers that have transparent surfaces and can be filled with water. The transparent surfaces of the containers are made from a plastic that allows the penetration of a large portion of UV light, specifically UV-B which is highly effective at destroying microorganisms. Water is poured in through an opening that houses a filter of 35 microns to remove larger particles〔(Solvatten product brochure )〕 Once filled, the unit is placed in direct sunlight, which simultaneously heats the water and exposes it to ultraviolet radiation. The combination of these is an effective means of purifying water and, depending on conditions, the water will be free of pathogenic material in 2–6 hours. The water is heated to between 55 and 75 °C,〔 making it suitable for a number of other household and hygiene purposes, such as hand washing, bathing and domestic cleaning. A study has shown that the use of SOLVATTEN is associated with health improvements in communities that are dependent upon contaminated water resources. It showed that it eliminated 100% of pathogenic material from water sourced from contaminated wells, whilst its use was also associated with as 60% reduction in diarrhoeal infections in children under five years old.〔 The study, conducted in Mali, showed that households using SOLVATTEN reduced their combustion of firewood and charcoal by an average of 0.5 and 0.9 Kg/day respectively.〔Diop, B. S. (2012) Sanitary, economic and environmental impacts of Solvatten in the West African peri-urban context: case of Dialakorodji, Bamako (Mali). University of Dakar, Senegal. ()〕 This had additional economic benefits for the user, with average savings of 15.8 USD/month.〔 A separate research exercise calculated the social return on investment (SROI) of SOLVATTEN, which accounts for extra-financial value (e.g. environmental and social value not reflected in conventional financial accounts) relative to resources invested. In that study, the SROI was calculated as being 1:26, meaning that for every unit of currency invested in SOLVATTEN, 26 were created〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Solvatten」の詳細全文を読む スポンサード リンク
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