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On March 21, 2011, the U.S. Environmental Protection Agency (EPA or Agency) published its final rule , Identification of Non-Hazardous Secondary Materials That Are Solid Waste (76 Fed. Reg. 15456), which defines as a solid waste any sewage sludge or biosolids that is combusted. Developed to assist EPA in its Clean Air Act (CAA) regulation of combustion units, including sewage sludge incinerators (SSIs), the rule has broader consequences for all sewage sludge that is burned directly in a SSI or processed into pellets for use as a fuel in other combustion units. The final rule is largely unchanged from the proposal – EPA continues to believe sewage sludge cannot meet key legitimate fuel criteria and is, therefore, a solid waste when combusted. Language in the preamble, however, limiting this finding to sludge that is incinerated, will help further reduce any potential impact of this rule on other sewage sludge management options.

NACWA believes that EPA’s final definition of solid waste rule is flawed and wrongly declares that all sewage sludge is solid waste when combusted. NACWA is proceeding with a formal legal challenge of the final rule, but the provisions in the rule remain in effect and NACWA prepared this Advocacy Alert to provide its members with an overview of the final rule and its implications for sewage sludge management. Advocacy Alert 11-11 provides a detailed explanation of the final CAA rule imposing air emissions standards on SSIs that result from this solid waste determination.

Background and Proposal

To meet its obligations under a 2007 ruling by the United States Court of Appeals for the District of Columbia Circuit, EPA initiated a rulemaking to define solid waste under the nonhazardous waste provisions of the Resource Conservation and Recovery Act (RCRA), starting with a January 2, 2009, Advanced Notice of Proposed Rulemaking (ANPRM). The solid waste rulemaking effort was intended to help EPA determine under which CAA section certain incinerators and boilers should be regulated. Under EPA’s proposed approach, combustion units burning solid wastes would be regulated under the more onerous Section 129 CAA requirements, while those burning ‘legitimate secondary materials’ (i.e., not solid wastes) would be regulated under Section 112 of the CAA. Sewage sludge was included in this definition rule as EPA believed that the 2007 ruling had called into question the regulatory status of SSIs.

On June 4, 2010, EPA issued its proposed rule outlining the criteria secondary materials like sewage sludge would have to meet in order for them not to be considered a solid waste. While NACWA had argued that EPA did not have the statutory authority to regulate sewage sludge as a solid waste due to the domestic sewage exclusion, EPA proposed to regulate any sewage sludge destined for combustion as a solid waste. Though EPA sought comment on a potential regulatory exclusion at NACWA’s request, the Agency at the time asserted that it had full authority to include sewage sludge as a solid waste. In the preamble to the proposed rule EPA also presented information indicating that it did not believe sewage sludge could meet the Agency’s legitimate fuel criteria, specifically the requirement that any secondary material fuel contain a level of contaminants similar to a traditional fuel (in this case coal). Furthermore, EPA outlined why it believed that current SSI units, even those with sophisticated waste heat recovery devices, were primarily designed for volume reduction or destruction and, therefore, could not qualify as an energy recovery device.

NACWA’s comments on the proposal offered expansive and detailed information supporting the Association’s view that EPA did not have the authority to regulate sewage sludge as a solid waste and provided updated and more contemporary data on contaminant levels in sludge.

In addition to commenting on the proposal, NACWA has provided comments on the ANPRM, sent top officials in EPA’s water, air, and waste offices a letter in September 2009, outlining why sewage sludge should not be considered a solid waste and why SSIs are more appropriately regulated under Section 112 of the CAA, and met several times with EPA and the White House’s Office of Management and Budget (OMB).

EPA’s Final Rule Largely Unchanged from Proposal

EPA’s March 21, 2011, final identification of non-hazardous solid waste rule outlines the conditions under which secondary materials would not be solid wastes when combusted. In the final rule, EPA continues to believe that sewage sludge cannot meet key legitimate fuel criteria and is generally burned in units that do not recover energy, and therefore is a solid waste when combusted, as discussed below.

The final rule also includes a non-waste determination process, a case-by-case approach through which a waste generator can petition the EPA Regional Administrator for a special ruling that their secondary materials are not solid wastes when combusted. These wastes must meet additional criteria in addition to the legitimate fuels criteria outlined in the rule.

All Sewage Sludge/Biosolids Destined for Combustion Considered Solid Waste
Based on EPA’s final rule, all forms of sewage sludge, including material that meets the Part 503 biosolids standards, pellets, and any other processed material from sewage sludge would be considered a solid waste when combusted. As structured, the regulations provide two main pathways for sewage sludge to potentially fall out of solid waste regulation:

• Section 241.3, paragraph (b)(1) states that “Non-hazardous secondary materials used as a fuel in a combustion unit that remain within the control of the generator and that meet the legitimacy criteria” would not be solid wastes. Sewage sludge burned in a SSI or dried sludge or pellets burned on-site by a utility would most likely fall into this category.

• Similarly, Section 241.3, paragraph (b)(4), states that “Fuel or ingredient products that are used in a combustion unit, and are produced from the processing of discarded non-hazardous secondary materials and that meet the legitimacy criteria” would not be solid wastes. Dried pellets or other biosolids products that are used as a fuel substitute by others (not the utility) would most likely fall into this category.
  

In both of these cases, however, all three of EPA’s legitimacy criteria must be met. The non-hazardous secondary material must be:

1. Managed as a valuable commodity;
2. Have a meaningful heating value and be used in a fuel that recovers energy; and
3. Contain contaminants at levels comparable in concentration to or lower than those in traditional fuels.

EPA made blanket determinations in both the proposal and the final rule that it does not believe that sewage sludge would satisfy the contaminant legitimacy criterion because of the presence of non-comparable levels of metals when compared to traditional fuels. In both rules EPA included a chart comparing average levels of key metals in sewage sludge compared to coal. NACWA was able to submit data to demonstrate that EPA’s comparison was inaccurate in the proposal, but the amended comparison chart in the final rule (see below) still indicated “higher levels, and those that EPA would not consider to be comparable for most of the contaminants found in sewage sludge when compared to coal [the traditional fuel EPA used when evaluating biosolids].”

Though the final rule does include a non-waste determination process, the legitimacy criteria must still be met. Processing and drying of sludge is not likely to reduce the metals concentrations that EPA says are not comparable to coal. It is unclear whether the process of gasifying sludge to produce synthetic gas, an emerging practice, would significantly reduce contaminant levels, but the final fuel product would have to meet all of the legitimacy criteria since it was processed from a solid waste. It is possible that sludge from a particular facility or facilities may have concentrations that fall below the average contaminant levels EPA provides in the final rule and therefore could be eligible for a non-waste determination. In such a case, a petition will need to be filed with EPA to seek a determination from the Regional Administrator. EPA has so far provided few details on how this petition process will work.

Burning in SSIs Not Considered Energy Recovery
The second legitimate fuel criterion requires the secondary material to have meaningful heating value and be burned in a unit that recovers energy. EPA has indicated in both the proposed and final rules that SSIs are not designed for energy recovery, but instead are designed for volume reduction and destruction. Therefore, burning in a SSI would meet the definition of ‘discard’ and the sewage sludge would be considered solid waste. Though many utilities have installed waste heat recovery systems, EPA believes the “presence of a waste heat boiler does not, by itself, change the fact that the unit…is primarily an incineration unit burning waste for disposal purposes.” EPA goes on to state that it “does not regard waste heat boilers as legitimate energy recovery devices” because they receive their energy from off-gases. Among other criteria, EPA requires that a “boiler’s combustion chamber and primary energy recovery section(s) must be of integral design”. This means that even if a particular utility’s sewage sludge has low contaminant levels and can meet all of the other legitimate fuel criteria, burning that sludge in a SSI will still be regulated as solid waste incineration.

Domestic Sewage Exclusion Does Not Apply to Sewage Sludge
For years NACWA has argued that POTW-generated sewage sludge is excluded from regulation under RCRA due to the domestic sewage exclusion. The statutory definition of ‘solid waste’ states that “solid or dissolved materials in domestic sewage” are not solid wastes. That language has been codified in the regulations as the domestic sewage exclusion and it has served to ensure that clean water agencies do not get pulled into hazardous waste rules simply because a sewer user may have discharged a hazardous waste into the system. EPA, however, in the proposed and final rules has continued to assert that the domestic sewage exclusion does not extend to POTW-generated sludges and, therefore, POTWs are generating a solid waste.

Impacts on Other Management Options/State Rules
NACWA has consistently raised concerns with EPA about the impact of its rulemaking on other biosolids management activities. As in the proposal, the final rule states that EPA’s determination is limited to the regulatory status of sewage sludge that is burned. EPA underscores that it is “not making solid waste determinations that cover other possible end uses (e.g., land application of sewage sludge).” EPA further asserts that the regulations should not dictate to state programs how to characterize and or regulate this material, “particularly since EPA does not have authority to regulate beneficial use of non-hazardous secondary materials under subtitle D [the non-hazardous section] of RCRA.”

While NACWA believes that this rule should have little or no impact on existing state rules, other than to dictate the federal CAA section under which certain incinerators should be regulated, EPA’s determination that sewage sludge is a solid waste in some circumstances may be used as evidence against land application or other reuse of biosolids by opponents of the practice. This remains a concern despite EPA’s assertions that its rule has no bearing on other management options.

NACWA Next Steps

NACWA is embarking on a multi-pronged legal effort to challenge the final SSI CAA standards and seek administrative review of those final standards. In tandem with those efforts, NACWA will also file a legal challenge of the final definition of solid waste rule, as a key regulatory underpinning for the SSI standards and as a major impediment to the use of biosolids as a renewable fuel source. NACWA must file its challenge to the SSI Rule by May 20, 2011, and the definition of solid waste rule by June 17, 2011, and has formed a Sewage Sludge Incineration Advocacy Coalition (SSIAC) to guide both efforts. NACWA member agencies that do not operate incinerators but are interested in participating in the work of the SSIAC as it relates to the definition of solid waste rule should contact Chris Hornback at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .