So You Operate A CISWI Unit – What’s The Good News?

Recall the March 2011 proposed Non-Hazardous Secondary Materials (NHSM), Commercial and Industrial Solid Waste Incineration (CISWI), and National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters (Boiler MACT) rules.  A major concern for owners and operators of boilers that used alternate or “non-traditional” (i.e., waste) fuels at that time was how specific emissions units would be regulated under the suite of proposed rules.  In accordance with the March 2011 proposed rules, a boiler would only be allowed to utilize waste fuel if the boiler was classified as an “energy recovery unit” under the proposed CISWI rule.  However, such sources could opt-out of CISWI and be regulated under Boiler MACT if they ceased firing fuels classified as waste.  For many owners and operators that were not yet sure whether their boiler could comply with the CISWI rule, some may have seriously considered ceasing their use of waste fuels until they were certain that their boiler could comply with the CISWI rule.

Remember also that at the time of the March 2011 proposed rules, it was unclear whether a boiler switching from firing a traditional fuel (e.g., fuel oil, coal, natural gas, etc.) to a non-traditional fuel (or waste) would be classified as a “new” or “existing” CISWI unit.  The confusion related to whether a fuel switch from a traditional fuel to a waste fuel would be considered as a modification, thereby subjecting an “existing” CISWI unit to more stringent new source CISWI standards.  So here’s the good news.  In U.S. EPA’s December 2011 proposed reconsideration of the CISWI rule, they clarified that a traditional fuel-to-waste switch alone would not cause a boiler to be classified as a “new” unit (i.e., if the boiler doesn’t trigger new source applicability for reasons other than the fuel-to-waste switch). Although only proposed, we expect to see this interpretation maintained in the final version of the rules, which U.S. EPA intends to promulgate any day now.