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November 21, 1997
AMSA Reviewing EPA Air Office Draft POTW MACT Proposal
AMSA received this week an advance draft of the long-awaited proposed maximum achievable control technology (MACT) standard for POTWs under Section 112 of the Clean Air Act. The draft is undergoing final review by EPA's Office of Air & Radiation and will soon be forwarded to the Office of Management and Budget for evaluation before it gets noticed in the Federal Register sometime in December. AMSA's Air Quality Committee is reviewing the draft and will submit comments by the November 28 deadline.
AMSA's preliminary assessment of the draft raises some potential concerns with how EPA intends to determine compliance with this regulation. EPA has apparently determined applicability of the MACT by dividing POTWs into two subcategories: (1) non-industrial POTWs (existing and new) and (2) industrial POTWs (existing and new). The draft defines industrial POTWs as those which "accepts one or more specific regulated industrial waste streams for treatment that enables an indirect discharger to comply with the treatment requirements of its own NESHAP." A POTW which "does not meet the characteristics of a publicy owned industrial wastewater facility" belongs in the non-industrial POTW subcategory."
Due to AMSA's efforts on this issue over the past four years it appears that the majority of existing POTWs and AMSA members will not be impacted by this proposal. EPA will not require controls for the majority of existing non-industrial POTWs. However, a new or reconstructed non-industrial POTW that is a major source of hazardous air pollutants (HAP) emissions (>10 tons/yr of a single HAP or >25 tons/yr of any combination of HAPs) must have covers on all treatment units up to the primary clarifiers. For existing industrial POTWs, the appropriate NESHAPs for the indirect discharger(s) will determine compliance date(s). For example, a facility providing treatment for chemical plants regulated by the Hazardous Organic NESHAP will have to comply by April 22, 1999. A new industrial POTW must be in compliance as soon it begins accepting the waste stream(s) for treatment. Future acceptance of specific regulated industrial waste stream(s) for treatment must be in compliance by the time specified in the appropriate NESHAP(s) for the indirect discharger(s).
Another potential concern with the proposal focuses on the determination of whether a POTW is a major source of HAP emissions. While this regulation addresses only wastewater emissions, the determination will consider emissions from all stationary sources at the facility, including sewage sludge incinerators, internal combustion engines, boilers, and turbines, which are currently being evaluated for MACT standard development under section 129 of the CAA. EPA includes a conservative emission factor table to estimate emissions for each of the 76 HAP compounds expected at POTWs. While POTWs may use other fate models to determine if they are a major source of HAP emissions, EPA will rely exclusively on the use of its highly conservative WATER8 model if there is any ambiguity concerning their status as a major source. If direct measurements are taken of influent HAP concentrations, samples must be prepared and analyzed in accordance with the requirements of Method 305 or Method 25D in 40 CFR part 63. While the Method 600/800 series typically used for wastewater sampling under 40 CFR part 136 can be used, the POTW must document the test method, sampling protocol, and analytical variability accounted for in determining the HAP concentration. Lastly, there is unclear language regarding what constitutes reconstruction or a change/modification to an existing POTW that would cause the facility to be subject to the requirements to install covers up to the primary clarifiers.
AMSA will evaluate comments received from Air Quality Committee to determine the appropriate response to the draft proposal. Copies of the pending Federal Register notice will be sent to the membership for review and comment via an upcoming Regulatory Alert sometime before the end of the year.
Ø There will not be a FaxAlert next Friday, November 28, due to the Thanksgiving Holiday.
Also, members are reminded that a new phone system was installed at the National Office today and therefore members may experience technical difficulty reaching staff during the transitional period.