杏吧原创

A 鈥済reen roof鈥� that cleans up waste bath water for flushing toilets has been developed by London鈥檚 Metropolitan Water Company (GB 2375761). A pool of waste water around 12 centimetres deep, which forms part of the roof, is covered by a rainproof membrane. Flowers grow through the membrane with their roots in the water. A solar-powered pump circulates the water around the roots, where micro-organisms digest any organic matter. The cleaned-up water is then diverted to the toilet cistern. The roof water stays at around 5 掳C, keeping the house warm in winter and cool in the summer.