Sludge Thermal Drying Porto Torres
ASI Consorzio per l'area di sviluppo industriale Sassari - Porto Torres - AlgheroPorto Torres | Sassari - Italy
- System description: Thermal drying
- Waste processed: Waste water t reatment sludge
- Plant capacity: 35,000 t /year
Ecomaster has built a plant for thermal drying of sludge deriving f rom waste water t reatment . The works, carried out on a “ turn-key” basis, have included the architectural and engineering design and the const ruct ion of equipment and related civil works.The sludge to be processed is unloaded by the t ransport vehicles direct ly in a storage hopper where it is ext racted and then conveyed to the drying line. The drier consists of a cylindrical double wall const ruct ion, which is heated by diathermic oil. An internal rotor projects the sludge towards the heated wall. Af ter evaporat ion of the water, the sludge powder is conveyed by the gas st ream passing through the drier to a cyclone followed by a bag f ilter, where it is separated f rom the gas f low. The energy for the evaporat ion is supplied by an oil-fuelled diathermic oil boiler. To prevent condensat ion of the water vapour inside the circuit , ducts, cyclone and bag f ilter are thermically insulated. Downst ream the f ilter there is a condenser and heat exchanger. The condensate is collected and discharged to the waste water t reatment system, while the gas st ream returns to the drier. A set of auger conveyors conveys the dry sludge to the roll-of f container. One of the auger conveyors is water cooled to reduce the sludge temperature.
A fan provides the pressure required to compensate the system pressure loss and to recirculate the gas st ream. A small f ract ion of the gas is sent to the combust ion chamber of the boiler, where the organic compounds are burnt . The plant includes the required safety equipment and is cert if ied according to the ATEX regulat ions. Drying of the sludge drast ically reduces its weight and this allows a signif icant saving in landf ill fees. In addit ion, the heat ing value of the dried sludge is high enough to use it as an alternat ive solid fuel. The energy generated f rom the combust ion of dry biomass is renewable energy.