ABSTRACT
Residual solids from wastewater treatment processes are often dewatered prior to disposal on land or in landÞlls or before further processing (drying, pelletizing, composting, incineration). During dewatering, any volatile compounds present may be stripped or volatilized from the solids. In many cases, the dewatering processes are covered, with headspace air exhausted to foul air collection systems for odor control. In other situations, the process units may be placed in enclosed buildings equipped with exhaust systems, again as an odor control measure in the buildings. In either case, the continuous replacement of process headspace air with “clean” air leads to the maximum driving force for volatilization of organic compounds from the solids. This chapter discusses biosolids dewatering processes most widely used at POTWs and describes VOC transfer in the dewatering process. VOC transfer studies are also reviewed.
