Scientists at the Environment Agency's national laboratory at Starcross, near Exeter, UK, have been putting a pioneering water purification filter through its paces
The Seychelle In-Line Eliminator is a personal water purification system designed for campers, hikers, cyclists and the military.
The compact filtering system can be fitted to the drinking tube of most hydration packs and gravity feed water systems such as Camelback, Platypus and Blackhawk Tactical Gear.
"The UK representative of the filter's American manufacturer visited the Starcross laboratory and asked us to test it to its limits," said Wayne Civil, head of the laboratory's research and development team.
"They were keen to test the filter's ability to remove micro-organisms causing particularly harmful diseases such as anthrax and polio".
The challenge for the scientists at Starcross was to create surrogate organisms that would mimic the real organisms that were too dangerous to use.
The device had already undergone tests in America but the manufacturer, Seychelle Environmental Technologies, from California, was keen to have it tested by an independent UK laboratory to meet the latest Ministry of Defence specifications.
The cylinder-shaped device comprises three main components - a coconut carbon filter, a ceramic disk and iodine coated beads.
Any large organisms are effectively 'shredded' on the ceramic disk.
An electro-static charge around the iodine-coated beads attracts smaller organisms rendering them harmless.
The carbon filter then traps and retains contaminants.
More than 150 rigorous laboratory tests were undertaken to measure the filter's ability to remove a range of harmful substances.
These included E coli, cholera, salmonella and hepatitis bacteria; polio, norwark, meningitis and anthrax viruses; parasites such as giadiosis, cryptosporidium, bilharzia and weils disease; heavy metals such as lead, copper, aluminium, mercury, radon 22 and cadmium; and industrial chemicals such as nitrates, PCBs, benzines and DDT.
The filter also had to remove the chlorine and iodine used in the disinfecting process, leaving the user with clean, safe, odour and taste-free water.
"Each filter test was challenged with 300 litres of water cumulatively seeded with a combination of organic, metal, inorganic and microbiological contaminants to represent potential field operation conditions," continued Civil.
"It turned into a real team effort with our colleagues in micro-biology producing samples of surrogate organisms for us to test in the filter".
The filter was found to remove up to 99.9% of harmful contaminants; exceeding expectations and meeting the stringent requirements of the MoD.
"This project posed some tough technical challenges, but the excellent outcome more than made up for the time and effort we put in.
"In addition to testing, we suggested some improvements to the filter design.
"By delivering a successful solution we have satisfied a customer who is delighted with the results".
The filter provides up to 450 litres of filtered water and has proved so effective it is now in use by the Special Air Service and Royal Air Force.
"The professional service provided by the Environment Agency's National Laboratory Service at Starcross was outstanding.
"We could not have sought better advice and testing from any other laboratory.
"The results were impressive and will provide a bench mark standard for future tests recognised the world over for these systems", said Giles Butler, UK spokesman for Seychelles Environmental Technologies.
