Experimental Study on Control of Odor from Dewatered Sewage Sludge in Landfill by Additives
Landfill of dewatered sewage sludge which has not been bio-stabilized has faced strong odor problems.Modifying additives,such as coal fly ash,aged refuse,building wastes and soil taking as the contrast,were selected to mix with sewage sludge to control odor effectively,targeting waste utilization and waste control by utilizing waste.It is found that the sequence of deodorization capability from strong to weak is coal fly ash,aged refuse,building wastes and soil.The aged refuse should be the priority option of additives to mix with sludge when sludge is to be disposed into the existing landfills,as it is easy available,of large quantity and not to occupy extra space of landfill.It is shown that the more the aged refuse added,the weaker the odor from modified sewage sludge was,but the less concentration of hydrogen sulfide in odor reduction was.The removal of hydrogen sulfide could reach 96% when the ratio of aged refuse to sludge is 7:10.The odor of the sludge mixtures could be reduced to lower than 3 levels,conforming to the emission standard of odor pollutants in landfill when 4 kinds of modified additives are added in the minimum mixing ratio meeting the strength requirements for landfill.