hydrodynamic screw(Hydrodynamic Screws are designed for the production of electric energy. The machine works thanks to the difference of energy potential between two different points in a water flow. The water, thanks to the difference between two levels of natural flow, is used by a rotor that generates energy) and then flows again into its channel. The limit of this equipment is reached with geodetic heights of more than 10 metres and flow rates higher than 5,500 l/s. tisys.rusega_tarasov)
water treatment plant(Building work on a Ј16m water treatment works in York has begun. The plant, at Acomb Landing, will replace the existing works which has provided drinking water for the city since 1846. BBC Alexander Demidov)
