The Millennium Dome "Watercycle" experiment: to evaluate water efficiency and customer perception at a recycling scheme for 6 million visitors.

Thames Water's "Watercycle" project at the Millennium Dome was one of the largest in-building recycling schemes in Europe, designed to supply up to 500 m3/d of reclaimed water for WC and urinal flushing. It catered for over 6 million visitors in the year 2000. Overall, 55% of the water demand at the Dome was met by reclaimed water. The site was also one of the most comprehensive studies ever carried out of water conservation in a public environment, evaluating a range of water efficient appliances and researching visitor perceptions of reclaimed water. Within the Dome there were six identical core buildings housing the washrooms, which were equipped with a variety of different water-efficient devices for comparison. Water usage by the different appliances was monitored using a sophisticated metering and telemetry system. The importance of correct installation and maintenance of "high tech" water efficient devices was highlighted during the research programme, as some water wastage occurred due to poor installation. The results prove that metering should complement any large-scale water efficient system, so that any faults with the appliances can be quickly identified. The visitor survey showed very positive attitudes to the use of reclaimed water for non-potable uses.