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REPORT OF PYROLYSIS OF SEWAGE SLUDGES IN THE NEW YORK-NEW JERSEY METROPOLITAN AREA (PHASE I)
Citation:
REPORT OF PYROLYSIS OF SEWAGE SLUDGES IN THE NEW YORK-NEW JERSEY METROPOLITAN AREA (PHASE I). U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-81/202 (NTIS PB82105537), 1981.
Description:
The purpose of this work was to reduce the volume of municipal wastewater (sewage) sludge in a multiple-hearth furnance via starved air combustion (pyrolysis) to determine how it compared with incineration as an environmentally acceptable method of sludge disposal. Sludge was first dewatered to 35-50 percent solids content in a plate and frame filter press having expandable rubber diaphram plates. The dewatered sludge was then thermally converted to ash and/or char in a .91 m (36 inch) inside diameter pilot scale multiple-hearth furnace having six hearths. Thermal conversion consisted of incineration at 900 C (1625 F) and starved air burning (pyrolysis) at 700 C (1290 F) to 900 C (1625 F). Heat contents of the off-gases and the ash and/or char mixtures were determined. The amounts of heavy metals retained in the ash and/or char were determined. Heavy metals retained by each mode of operation were compared to determine which process would cause the least air pollution. Toxic organics in the sludge were reduced below detectable limits in the ash and particulate emissions. This applied to all modes of operation. Particulate Emissions from starved air combustion (pyrolysis) were less than for incineration in most cases. A cost estimate for conversion of an existing plant to the starved air mode of operation is included in the report.