Many operators press run thin sludge through a chamber filter press and take it to the disposal site. Such sludge still contains some 60 to 70 percent of water. The high disposal cost is actually spent on water. Those who choose to dry their sludge after dewatering and invest in an energy efficient condensation dryer with integrated heat pump will save a lot of money. Drying reduces the weight and volume of the sludge by as much as 60 percent, and the disposal and transport cost in equal measure. Some types of sludge may obtain a more favourable classification which provides potential for more cost savings. In the event that the sludge contains valuable materials recycling might even create new revenue. Harter dryers with a heat pump were classified as future fit technology in 2017. Customers may thus enjoy government subsidy.