Dewatered sewage sludge treatment, recovering reducing problem of sludge disposal

摘要

Treating sewage sludge in water treatment works comprises: (a) drying dewatered sludge in a fluidised bed drier until the water content has been reduced to a maximum of 10%; (b) gasifying the dried sludge in a de-oxygenated environment in a fluid bed gasification unit, making a product gas; (c) using the product gas as fuel for a district heating unit; (d) returning effluent heat from the fluid bed gasification unit and district heating unit through a closed pipe system to the fluidised bed drier; (e) dewatering the sludge in a high pressure chamber filter press; (f) mixing dewatered sludge with dried sludge and converted into pellet form; (g) drying product gas by steam condensation; (h) surrendering the district central heating unit waste heat via a heat exchanger; and (i) serving water discharged from the filter press to condense steam from the fluid bed gasification unit.