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The U.S. Environmental Protection Agency’s (EPA) Non-Hazardous Secondary Materials (NHSM) rule (March 21, 2011; 76 Fed. Reg. 15456) defines all municipal sewage sludge destined for combustion as a solid waste.  Combustion of a solid waste triggers stringent Clean Air Act (CAA) requirements, but EPA’s NHSM rule provides a pathway for sludge that is processed into a legitimate fuel to avoid the most stringent air emission requirements.

This Advocacy Alert supplements and updates Advocacy Alert 11-12 with additional information on proposed changes to the NHSM rule and new information on obtaining a non-waste determination for sewage sludge.  These changes and new information will unfortunately not benefit sewage sludge incinerators (SSIs), which must still work to meet the recently promulgated CAA standards in 40 CFR § 60 Subpart LLLL (new sources) or Subpart MMMM (existing sources) (See Advocacy Alert 11-11).

NACWA continues to fight to preserve a range of management options for sewage sludge, including incineration, and is actively challenging both the NHSM rule and the CAA standards for SSIs[1]. However, both rules remain in effect and the Association is working on a parallel track to ensure these rules have the least impact on sludge management.

NHSM Rule Non-Waste Determination for Biosolids

While the Association disagrees with EPA’s general finding that all sewage sludge is a solid waste when combusted and has filed a judicial challenge of that decision, the NHSM rule remains in effect.  Accordingly, NACWA has been working to ensure that the rule presents minimal impediments to the use of sewage sludge or biosolids as a renewable fuel and that this option remains viable into the future.  NACWA had hoped to dissuade EPA from making a blanket statement that all biosolids are solid wastes when combusted and had made a compelling argument that SSIs can recover a significant amount of energy with the appropriate equipment.  EPA’s final NHSM rule, however, provides only a small window for biosolids, combusted in units other than SSIs (which EPA has determined are designed for waste destruction, not energy recovery), to qualify as legitimate secondary material fuels.

Under the NHSM rule, clean water utilities that wish to dry and burn their own biosolids for energy recovery can do so through the self-implementing provisions of 40 CFR § 241.3.  The self-implementing provisions only apply to biosolids that “remain within the control of the generator”, which is specifically defined in § 241.2.  By demonstrating that its biosolids have been sufficiently processed and can meet EPA’s legitimate fuel criteria, a utility can burn the biosolids for energy recovery – in compliance with any applicable CAA requirements for the combustion unit – without triggering the more onerous requirements for a solid waste combustion unit.  Some of the proposed revisions to the NHSM rule, discussed below, should make it easier for a utility to take advantage of these self-implementing provisions.

There has been recent interest by industries currently burning coal to use dried biosolids pellets as an alternative fuel.  Any public utilities interested in providing biosolids to a third party for use as a fuel, can petition for a non-waste determination from the appropriate EPA Regional Administrator.  This determination only applies to the biosolids from the particular facility requesting the determination.  Without this non-waste determination, the third party user of the biosolids fuel would have to comply with the more stringent CAA requirements for burning solid wastes.  Key to making this determination is demonstrating that the solids have been sufficiently processed and can meet the legitimate fuel criteria in § 241.3.  The criterion that will likely present the biggest challenge for biosolids is the contaminant level criterion, which requires that the biosolids have levels of contaminants (as defined in § 241.2 – revisions are proposed for this definition; see below) comparable to a traditional fuel.

EPA has consistently used coal as the comparison fuel for biosolids.  EPA has provided some information on its website for determining the typical contaminant levels in traditional fuels including coal, but utilities can use other sources as well in accordance with § 241.3.  EPA is proposing revisions to this section to clarify that “ranges of traditional fuel contaminant levels compiled from national surveys, as well as contaminant level data from the specific traditional fuel being replaced” can be used for comparison.

NACWA was encouraged to learn that a community in Michigan has already successfully gone through the petition process for its biosolids.  EPA’s formal non-waste determination letter for that community is posted on the EPA website.  NACWA obtained the community’s original submittal to EPA and is making this information available to members interested in pursuing such a determination:

Non-Waste Determination Submittal – Delhi Charter Township – Holt, Michigan

• June 16, 2011 - Application for a Non-Waste Determination
• Revised Pollutant Concentrations (“as fired” and not on a dry weight basis)
• EPA Region 5 Final Approval Letter

Proposed Revisions to the NHSM Rule

NACWA submitted comments February 21 on EPA’s reconsideration of, and proposed revisions to, the NHSM rule (76 Fed. Reg. 80452; December 23, 2011).  NACWA is optimistic that the additional clarification and proposed categorical non-waste determination process could make it easier for those utilities that are interested in burning dried biosolids as a fuel or fuel substitute.  The proposed revisions to § 241.3 help to clarify elements of EPA’s legitimate fuel criteria and should make the non-waste demonstration (discussed above) less cumbersome.  The new, proposed categorical non-waste determination process may provide an opportunity for an industry-wide exemption, but it remains to be seen whether biosolids, which can be significantly variable in terms of pollutant levels, could qualify for the categorical determination.  NACWA will look further into the possibility of using the categorical determination for biosolids.

EPA intends to finalize the revisions to the NHSM rule this spring.  NACWA’s legal challenge to the NHSM rule has been placed in abeyance pending the Agency’s final publication of revisions to the rule.  The Association will update members as developments occur on this issue.

[1] NACWA has filed a legal challenge of the Subpart LLLL and Subpart MMMM air emissions standards (NACWA v. EPA), but the rules remain in effect and SSIs must be in compliance by no later than May 2016.