New MACT to Tax Adaptability

The U.S. EPA continues to review comments on the new rules it proposed last year to strengthen emissions controls on hazardous-waste incinerators and cement kilns. These MACT standards, once promulgated, will affect the types of wastes fed, their manner of being fed, and the kind of equipment needed because they are expected to require

• Emission limits for a number of pollutants not covered in existing permits. These include dioxins/furans, metals, chlorine, total hydrocarbons, and carbon monoxide (CO).
• Continuous emission monitors (CEMS) for non-classical parameters. The EPA will require, at a minimum, CEMs for CO and oxygen (O2). The agency has stated that monitors for particulate matter, mercury, and HCl/Cl2 may serve as "traffic cops" to control unit operations and trigger emergency shutdowns when incinerator emissions exceed permitted levels.
• Retrofitting additional control systems. Combustion units unable to meet the MACT standards may require potentially costly retrofits, especially for substances such as polychlorinated dioxins and furans.

Moreover, meeting the standards will not automatically constitute compliance. Under EPA's National Combustion Strategy, every RCRA combustion facility must perform a site-specific, multi-path risk assessment. For some facilities, the results of this assessment may dictate emissions limits more stringent than MACT standards.

Factors for Decision-making

Captive incinerator operators will need to balance anticipated compliance costs against shutting down regulated units. In many cases, the financial benefits of thermal waste treatment will continue to outweigh any new compliance hurdles. However, unit closure costs will be just one factor to consider in any decision to switch to off-site disposal. The shutdown of on-site units may increase the demand for commercial waste disposal services, driving up price.

Other important issues influencing a final decision on whether or not to continue incinerator operations include the

• costs and potential liabilities of off-site waste disposal;
• need to upgrade air-pollution-control systems to meet the MACT standards;
• potential downtime and record keeping associated with installation and operation of additional CEMs;
• activities associated with permit renewals for combustion units; and
• impact on waste feed materials, such as limits and feed rates.

In many cases, compliance will require upgrading pollution-control equipment, such as installing carbon injection or catalytic-based systems to control dioxin/furan emissions. Carbon injection may, in turn, require upgrading the particulate-control systems to remove added particle loading. The wastewater-treatment systems also may require upgrading to remove carbon from scrubber waters prior to discharge or reuse.

Permit Renewal

Coincident with the upcoming MACT standards, many units also face expiration of RCRA permits. The time and effort associated with preparing for permit-renewal application, agency negotiation, trial-burn planning, and risk assessment could be substantial. In many cases, agencies will use permit renewals as opportunity to impose additional restrictions, including the need to meet standards for metals, CO, dioxins/furans, and chlorine.

Non-conventional CEM Systems

The MACT rule will require CEM systems to be linked to waste-feed cutoff systems. Whereas CO and 02 monitors have been used for years, monitors for metals, particulates, and chlorine have yet to reach a high level of operational reliability. The potential downtime of new CEM technology could seriously impede incineration-unit operating efficiency. Other concerns include the costs of new CEM systems (for example, the capital cost of a mercury monitor may exceed $100,000) and, more important, those associated with capturing and reporting a significant amount of data.

RCRA/CAA Coordination

The hazardous-waste-incineration MACT standards will be promulgated under the Clean Air Act (CAA). Requirements under both RCRA and CAA will require close coordination to achieve reasonable permit conditions. However, the agencies responsible for implementing the two programs may disagree on requirements for a specific unit. To negotiate the most sensible permit, incinerator operators will need an in-depth knowledge of both sets of rules and a sound grasp of the different agencies' policies and procedures.

Above all operational flexibility will continue to be a key for facilities that continue incinerating under the new standards.

Nick Pangero is director of Combustion Programs at ENSR. This article is adapted from his ENSR white paper "Concerned About Your Hazardous Waste Combustor?" ENSR provides solutions to environmental problems for both industry and regulated government organization from more than 75 locations internationally. ENSR, 35 Nagog Park, Acton, MA 01720. Tel: 800.722.2440

Edited by Paul Hersch