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RELATIONSHIP BETWEEN FREE LIQUIDS AND SOLIDS CONTENT FOR SEWAGE SLUDGES
Citation:
Farrell, J. AND R. Gerstle. RELATIONSHIP BETWEEN FREE LIQUIDS AND SOLIDS CONTENT FOR SEWAGE SLUDGES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/303.
Description:
EPA guidelines for disposal of solid waste to landfills require that the waste contain no "free liquids", where the absence of free liquids is demonstrated by the EPA-prescribed pain filter liquids test (PFLT). his requirement applies to wastewater treatment sludges disposed to landfills. his investigation was conducted to determine whether solids content of sludges could be used in lieu of the PFLT since most treatment plants routinely determine solids content of their sludges. he experiments carried out demonstrated that solids content required to pass the PFLT ranged from 5.5% for waste activated sludge to 15.6% for primary sludges. gitation such as might be encountered in truck transport of sludge to a landfill did not cause sludges that initially passed the test to fail; however, some sludges that initially passed the test failed after standing for 24 hours. equirement that sludges meet a solids content criterion instead of passing the PFLT is not recommended. he solids content at which all wastewater sludges pass the PFLT would have to be set at about 20% solids. ew biological sludges can be dewatered to this high a solids content using conventional dewatering equipment. f a single solids content criterion were established, these sludges would require an additional dewatering or drying step before they could be disposed in a landfill.