Preliminary evaluation of the use of powdered coal as a natural gas substitute for sewage sludge incineration. Final report, June 1--November 30, 1977

Abstract

Data was collected from each EPA region, each state environmental protection agency, and certain U.S. cities relative to oil, gas, and electricity usage for purposes of wastewater sludge incineration. At present, in the U.S., 7.2 x 10/sup 12/ Btu of premium fuels are utilized for sludge incineration, 68% of which is from gas and 31.5% from oil. Major urban areas at present utilize 3.5 x 10/sup 12/ Btu/yr of these fuels of which 99.5% is from natural gas. By considering sludge incinerators planned and under construction, it may be expected that by 1980, about 9.1 x 10/sup 12/ Btu of premium fuels will be used for this purpose. If ocean dumping and landfilling of sludge were prohibited, and all major urban areas were to utilize sludge incineration, about 32 x 10/sup 12/ Btu (or 159,000 heating equivalents) of premium fuels would be used for this purpose. Coal may be utilized to replace the premium fuels used for sludge incineration. Powdered coal may be utilized in biological reactors as nucleation sites for bio-floc development resulting in enhanced biological processing efficiency, while the resulting coal--biological sludge mixture may be sent to the sludge incinerator. Powdered coal usage at levels dictated by bio-reactor requirements indicate that the possibility exists to recover surplus coal--sludge generated energy from incineration and that 60 x 10/sup 12/ Btu ofpremium fuel would be up for public use. The total social impact of this incinerator is about 450,000 home heating equivalents of energy, about 77.5% of which is located in major urban areas.