Incorporation of rapid thermal conditioning into a wastewater treatment plant

Rapid thermal conditioning is a developing technology recently applied to sludge treatment. Sludge is heated rapidly to reaction temperature (up to about 220°C) and quenched after 10 to 30 s. This process reduces the amount of biosolids requiring land disposal by increasing its biodegradability and dewaterability. Rapid thermal conditioning may be incorporated into a wastewater treatment plant where, combined with anaerobic digestion, it would reduce the quantity of biosolids requiring disposal, eliminate the need for polymer coagulant, improve dewaterability, increase methane production, and further reduce the concentration of pathogens. Also, the odor problem associated with traditional thermal conditioning processes is largely minimized. Pilot scale equipment was used to assess the process and provide design parameters for scale-up. Introduction of the process into an existing municipal wastewater treatment plant was then evaluated using the Wards Island Water Pollution Control Plant of New York City as an example. Two alternative flow sheets are shown together with preliminary engineering designs. Cost estimates for these alternatives show a substantial advantage in comparison to present plant operation.