Sludge is dried from 16-25 % DS to 65-90 % DS, using hot (about 130 °C) air. All kinds of energy sourves can be used for to produce hot air.
Oil, gas, biogas, steam for example can be used for warming air. Also thermal oil is possible as an closed circuit. In all case warming is carried out
with indirect safety way. The Belt Dryer itself is slightly in under pressure, which guarantee that odour and air stay inside the dryer. The dryness of inffeeded sludge
is not significicant in thermal process, but the total efficiency is the most significant. So the most suitable dewatering device before the Belt Dryer is Belt Filter Press.