Screw Pumps are an efficient means of lifting large quantities of water or wastewater at low heads.  They can handle large volumes of  liquid at relatively low lifts and operate at  or above 70 % of efficiency for 2/3 of their operating capacity – all powered by one single constant speed drive. Furthermore there is no friction with pipes etc. so that screw pumps require little horsepower. Pre-screening is not needed, and the pump operates reliably without much attention needed.