Beyond the Call

IT'S NOT OFTEN that a company in a highly regulated industry looks forward to more rules, but Teris North America, Dallas, used newly imposed federal Clean Air Act requirements to transform its 30-year-old El Dorado, Ark., incineration facility into a multi-technology center for complex wastes management.

In 1999, the U.S. Environmental Protection Agency (EPA), Washington, issued maximum achievable control technology (MACT) standards to reduce airborne emissions from hazardous waste incinerators. Teris knew that to comply, it would be spending millions of dollars to upgrade its El Dorado facility's two high-capacity rotary kiln incinerators. Tony Clark, the company's vice president of sales, said that from a customer perspective, the MACT standards had the potential to reduce the number of treatment, storage, and disposal facilities (TSDs) nationally, as well as the range of wastes they could manage.

Many companies try to manage emissions by limiting what goes into the incinerator and cutting back on accepted waste streams, Clark says. However, the El Dorado facility did not want to limit its functionality and lose customers. So the company decided to exceed the emissions requirements to maintain its customer base and expand its range of services.

As part of complying with the standards, the company had two major goals: Keep downtime to a minimum during upgrades and improve the facility's production capabilities. This required replacing the incinerator's existing secondary combustion and emission control systems — literally everything between the kilns and the exhaust stack — with new technology. Yet there was one hitch. The MACT standards anticipated using “wet scrubber” technology to reduce dioxins and furans, and a conventional “dry” cloth filter and baghouse system to reduce particulates. Both were proven systems, says Gary Usery, engineering manager, but configuring the systems to work created technical challenges.

For the solution, the company turned to a four-step scrubbing system comprised of a saturator, twin parallel spray tower condenser columns and a high-energy scrubber with a de-mister, followed by a baghouse. Process gas is reheated prior to entering the baghouse to keep it above the dew point. Carbon also is injected to help enhance the removal of pollutants.

To reduce facility downtime during construction, the company built the new system onsite, then cut out the old system and installed the new one. Most of the major components for the new system were fabricated offsite and shipped to El Dorado. The greatest challenge to integrating the new system was physically connecting and commissioning the system in a minimum amount of time without error. Some of the ductwork is refractory-lined and weighs several tons, so maneuvering it 100 feet in the air above the operating process area was a challenge, Usery says. There were only four connection points for the new system — one for each kiln, one for the waste-fired boiler and one at the stack. Crews worked 24-hour days to cut out the old ductwork system and connected the new system nine days later.

According to Bill Ziegler, Teris' vice president for health, safety and environmental affairs, now that the system is working as planned, it is exceeding the emissions standards. More importantly, however, the process has taught the company that it can continue facility operations, even during routine maintenance. “Instead of having to shut down for two weeks of maintenance every 16 months, that work is performed automatically during normal operations,” Ziegler explains.

Because of the project's $32 million cash outlay, the company secured financing from the Little Rock-based Arkansas Development Finance Authority. The company qualified for aid as a startup operation because the company was still in process of acquiring the El Dorado facility from ENSCO at the time of construction. The project was financed through 18-year bonds.
Eric Gernath CEO, Teris North America Dallas