Cleaning Flue Gas from Sewage Sludge Incinerators Using an Electrostatic Precipitator and Polystage Chemical Scrubber

A study of a wet electrostatic precipitator (ESP) and chemical scrubber for flue gas cleaning was conducted on the multiple hearth sewage sludge incinerator at the New England Treatment Company (NETCO) facility in Woonsocket, RI. The ESP achieved the highest removal rate for heavy metals and particulate matter to a submicron range, while the two-stage chemical scrubber was able to oxidize and dissolve the incoming NO_x in the scrubbing solutions. This paper describes the details of sewage sludge incineration systems, NO_x emissions from a multiple-hearth sludge incinerator, and the current regulatory status; it also presents the results obtained from the commercial-scale ESP and the portable scrubber.