Unicef called upon the services of engineer Andreas Hammar to build the provocatively-named Sweat Machine which purifies sweat into drinking water. Though not intended as a serious measure to tackle shortages in drinking water, Unicef does hope to raise awareness of the issue, and invited visitors and footballers at last week's Gothia Cup soccer tournament to partake of a glass.

At the heart of the machine is new water filtration technology (used for the first time in this machine) which was developed by HVR and The Royal Institute of Technology in Stockholm called Membrane Distillation. The system uses a plastic cassette in which the water to be filtered is heated into vapor and circulated between two membranes, the other sides of which are cold. It's the resulting difference in pressure that forces the vapor through the membranes, causing, HVR says, the "absolute separation of all non-volatile substances."

Footballers Mohammed Ali Khan and Tobias Hysén were the first to sample water from the machine during last week's Gothia Cup

Inside the Sweat Machine, the result, Hammar claims, is drinking water even cleaner than water from Swedish faucets. Hammar told the the BBC that one sweaty t-shirt typically provides about 10 ml (0.4 fl oz) of water, which equates to about a mouthful.

On Thursday the BBC reported that, according to its makers, 1,000 people had tried drinking water purified from sweat during last week's Thursday. In an apt twist, given the underlying goal of raising awareness, demand for water from the machine reportedly outstripped the supply of sweat. "So we've installed exercise bikes alongside the machine and volunteers are cycling like crazy," Mattias Ronge of advertising agency Deportivo told the BBC.

Sources: Unicef, BBC