Research On Drying Characteristics Of Sewage Sludge And Belt Drying Process By Medium Temperature

There is a great deal of sludge produced in wastewater treatment plant. It has thecharacteristics of high water content, accumulation of toxic and harmful substances,organic matters and inorganic matters. Many researchers have focused on scientificand effective treatment and disposal technology of municipal sludge.It analyzed common sludge treatment and disposal methods in the world, and theimportant unit of thermal sludge drying was chosen as research object. Based ondrying experiment, design and operation practice of sludge drying project ofdewatered sludge in Shenzhen Nanshan wastewater treatment plant, it concludedsludge drying characteristics oand research results of medium temperature belt drying,which would supply references for research and project practice of Chinese sewagesludge treatment and disposal.Drying experiment was carried out as following: sludge particles with diameters of10mm,20mm and30mm at constant temperature drying conditions of105℃, sludgeparticles with diameters of10mm at constant temperature of90℃,105℃,120℃and135℃. It was found out that sludge ball experienced three stages during drying:acelerated drying, constant temperature dyring and falling rate drying, and dryingspeed was tightly related to drying temperature and sludge particle dimensions.Higherdrying temperature was, and less sludge particle dimension was, higher drying speedof specific sludge area, less time demanded for water content of balanced drying.Based on sludge drying experient, thermodynamics model was introduced. Byreduced time figure and fixed temperature linear fitting figure, most probable reactionmechanism functional integration equation was concluded:.Integration with Arrhenius thermodynamic equation,drying speed constant for sludge ball with diameter of10mm was obtained, andapparent pre-exponential factor A=118.78and apparent activation energy E=31.411kJ/mol.Combining with sludge drying theory and Sludge Drying Project in Shenzhen, itstated Circular Economy idea, system composition, thermal balance and mass balanceof Shenzhen Sludge Project.According to European Union safety production laws andnorms, safety production measures of Shenzhen Sludge Drying Project weredetermined. Odor and major pollutants in condensate water were detected during operation, and it analyzed odor discharge law and chemical odor removal processeffect, and high concentrations of organic wastewater formation and concentrationcharacteristics during drying condensation, and it pointed out process measures fordischarging to meet the standards.Finally, dried sludge was used for firing shale or clay brick experient, it analyzedinfluences of mixture quantity, firing temperature and firing time on fired brick. It wasfound that firing shale-sludge brick met Fired Perforated Bricks(GB13544-2000) inChina in intensity, appearance, heavy metal solution, radiation. It supplieddetermination foundation for resource path for dried sludge in Shenzhen DryingProject.