A running flush for membranes?
15 Jan 2000
Membrane filtration is just one of three innovative methods of water collection and recycling to be used at the Millennium Dome in Greenwich. The building's 20-acre roof will collect rainwater, which will then be filtered through a reed bed for primary treatment. This naturally occurring and environmentally friendly system has been designed by Thames Water using reeds similar to those growing locally.
Water is also being obtained from a borehole sunk by Thames Water's engineers at the construction site. This groundwater is unsuitable as drinking water because of its age and high salt content, but combined with rain water and water from wash basins and showers (grey water) around the site and primary treatment in the reeds, it is to be processed through two Leopold membrane plants to make it suitable for flushing toilets. The reclaimed water at the site should provide 50,000 litres of water needed every day to cater for the estimated 83,000 flushes.
The first membrane unit is a hollow fibre ultrafiltration plant and the second is a reverse osmosis plant.These methods are to be assessed to establish whether or not they can be used in the future to solve the problem of grey water treatment.
