Air pollution control for waste to energy plants - what do we do now?

Recent regulations require owners and operators of many waste-to-energy facilities to upgrade their existing air pollution control equipment. While it makes sense for some of these to install systems which meet BACT (Best Available Control Technology) standards, for others such a route could be less than the best choice. For the purpose of this discussion the authors will consider BACT standards to be at least 90% SO{sub 2} reduction and 95% HCl reduction. For SO{sub 2}, this is higher than required by new source performance standards (NSPS) as defined in December, 1995. An air pollution control system to meet BACT standards generally includes a spray dryer injecting lime slurry, addition of other reagents for control of mercury, etc., and use of a fabric filter. For many units, a less expensive upgrade which seeks only to meet the latest regulatory requirements might be optimum. In some instances, this could be the difference between a plant continuing in operation, or closing. Political uncertainties and the current economic climate make these decisions very difficult.