Meeting “New” SSI MACT 129 Limits

Sewage sludge incinerators (SSIs) located at Publicly Owned Wastewater Treatment Works (POTWs) are subject to the recently enacted US Environmental Protection Agency (USEPA) 129 emission limits, often referred to as the MACT 129 rule. These regulations set a time limit of March 21, 2016 for compliance with emission limits for both multiple hearth incinerators (MHIs) and fluidized bed incinerators (FBIs). They also establish new, more restrictive limits for “new” MHIs and FBIs. As a result, owners of existing incinerators have been evaluating compliance strategies to continue incineration or to shut down their incinerators and determine alternatives for the future processing of their sludge. Although most utilities currently operating SSIs fall under the MACT rule’s “existing” category for compliance, some are being classified as “new” per the MACT’s “50 percent rule” (Rowan et al., 2011) and are required to meet stricter “new” MHI emission limits.This paper discusses both operational considerations and emission control equipment that may be required for “new” MHIs and FBIs. This paper discusses recent experience with emissions control compliance for MHIs and how this knowledge may be applied to other MACT compliance projects, particularly those POTWs faced with a decision on implementing emission controls to meet “new” MACT limits to continue operating, or who want to understand potential future emission limits that may be implemented for “existing” MHIs.