Pretreatment of Sludge

摘要: Pretreatment technologies of sludge – thickening, conditioning, dewatering, drying are discussed. Thickening is a fundamental stage pretreatment. Pre-dewatering include rotary thickeners, gravity dissolved air floatation clarifiers and belt presses. The most widespread thickening method thickening. Sludge from wastewater treatment plants frequently conditioned, using chemical or physical means to alter the floc structures imparting sufficient stiffness incompressibility so that water entrained in can rapidly be drained through filtering other means. Dewaterability very important because it determines volume waste has handled. Dewatering performed by vacuum filters, filter presses, centrifuges, membrane Centrifuges presses currently popular dewatering methods due their good operation cost efficiency. primary sludges dewatered easily as these high fiber low ash. difficult solids high-rate biological systems. dewater containing ground wood fines. Drying flue gases combustion process standard method. Fluidized bed dryers, multiple hearth dryers found effective for drying.