Northampton Generating Co LP is nearing an air permit decision from the Pennsylvania Department of Environmental Protection for an Air Quality Plan Approval covering a revision to the permit limit for lead emissions (Pb) from a circulating fluidized bed (CFB) boiler located in Northampton Borough, Northampton County.
This revision is to address the variability of Pb content in fuel inherent with the multiple coal refuse piles that the plant currently uses. The company has sampled and tested approximately 21 refuse coal piles for lead content in order to determine the base line for lead. The results varied, ranging from 4.3 ppms to 140 ppms. NGC has used 140 ppms (highest lead found in the sample) in re-developing the lead emissions limit. Based on these sampling and findings the company has requested the department to revise the Pb limit, when burning Tire Derived Fuel (TDF), from 0.0027 pounds per hour to 0.0588 pounds per hour.
A Health Risk Assessment Model was provided to justify the revised lead emissions limit. No other operational changes were proposed by the company, the department said in a notice in the May 30 Pennsylvania Bulletin.
The department’s Central Office Air Quality staff reviewed the Health Risk Assessment results and concluded that for the increased lead emissions (0.0588 lb/hr = 0.00742 g/sec), the cancer risks for the baseline and TDF scenarios is 1.22 E-06. The non-cancer risks for the baseline and TDF scenarios have gone up slightly to 0.14 and 0.19, respectively, which are still below the acceptable level of 0.25.
Based on 8,760 hour per year operation and maximum of 140 ppm of lead content in coal refuse, the potential emissions from the boiler are expected at 0.258 ton/year of Pb.
The department will consider any written comments received within 30 days of May 30. A public hearing will be held on June 30 at the Northampton Community Center in Northampton, Pa.