Water Purifier Vestergaard Frandsen LifeStraw Family

Features Is a point-of-use microbial water treatment system intended for routine use in low-income settings Filters up to 18, 000 litres* of water, enough to supply a family of five with microbiologically clean drinking water for three years, thus removing the need for repeat intervention Ensures high flow rate and high volume of purified water Complies with US Environmental Protection Agency 1987 Guide Standard and Protocol for Testing Microbiological Water Purifiers: - Removes minimum 99.9999% of bacteria ( > Log 6 reduction) * - Removes minimum 99.99% of viruses ( > Log 4 reduction) * - Removes minimum 99.9% of protozoan cysts ( > Log 3 reduction) * Removes turbidity Requires no electrical power, batteries or replacement parts Requires no running water or piped-in water supply Has an easy-to-clean prefilter and purification cartridge All raw materials are US Food and Drug Administration compliant or equivalent * Note: based on laboratory trials with aging water of 15 NTU turbidity – A2 test dust and 5mg/ L humic acid and challenge water of 100 NTU turbidity – A2 test dust and 10mg/ L humic acid. Assumes normal cleaning in accordance with manufacturer’ s instructions Functioning At the time of first use, opening the exit valve removes all the air trapped inside the hollow-fibre membrane and wets the membrane surface, allowing an optimal filtration of the untreated water. The exit valve must be closed after 3 seconds. When untreated water is poured into the feed water bucket, the textile prefilter removes coarse particles larger than 80¼ m. Gravity pushes the water with particles finer than 80¼ m to flow down the plastic hose towards the purification cartridge. The purification cartridge, which contains an ultrafiltration ( hollow-fibre) membrane of 20nm porosity, stops all particles larger than 20nm ( including all microbes: protozoan parasites, bacteria and viruses) . Turbidity particles are also stopped by the membrane by size exclusion. The untreated water is pushed through the ultrafiltration ( hollow-fibre) membrane by gravity, i.e. by the pressure applied by the 1m long plastic hose, which corresponds to 0.1 bar pressure. This 0.1 bar pressure forces the water through the pores of the hollow-fibre membrane; particles and microbes larger than 20nm stay on the dirty side of the membrane and clean/ purified water passes through the membrane. Purified water can be collected from the blue tap. When the cleaning bulb is squeezed, dirt particles on the dirty side of the membrane are lifted by backpressure and then removed by flushing through the exit valve. Since all microbes are stopped by the 20nm membrane, the purified water complies with the US EPA requirements of LOG 6/ 4/ 3 reduction of microbes concentrations for water purifiers. The 0.1 bar pressure which allows the purification process to take place also leads to a flow-rate of 12-15L/ hour of purified water. The LifeStraw® Family filter also contains a chlorine chamber located below the top container. This chamber elutes low amounts of active chlorine, which protect the ultrafiltration membrane from fouling ( small amounts of active chlorine slow down the bio film formation on the hollow-fibre membrane) . The low amounts of active chlorine protect the ultrafiltration cartridge and that way lead to an extended lifetime of the LifeStraw® Family water purifier.