In-line treatment cuts Acme Foundry's disposal costs by 90%.

An in-line treatment-system designed specifically for Acme Foundry Co. preconditions cupola baghouse dust to a nonhazardous state and has reduced the foundry's disposal costs dramatically. Acme, located in Coffeyville, Kansas, is an iron castings producer, specializing in hydraulic valves.

With an in-line or Totally Enclosed Treatment System (TETS), wastes are treated prior to leaving the baghouse, thereby discharging nontoxic dust from the baghouse. Since the discharged dust is nonhazardous, it is not subject to the land ban or RCRA requirements.

Sincestart-up, Acme has realized a number of other benefits from its treatment system as well. 'Our treatment and disposal costs were cut dramatically-over 90%-and we were able to terminate our status as a hazardous waste generator," said Don Pusa, Acme vice president. 'In addition, the system helps preserve the environment and reduces disposal costs, which keeps us competitive."

Prior to using this treatment process, Acme retained a company to treat their waste on-site and then shipped it to a Subtitle C hazardous waste landfill for disposal. Costs for treatment and disposal averaged $475/ton of hazardous dust.

The foundry produces nearly 50 tons of iron castings per day and generates about 1400 lb of cupola baghouse dust per eight-hour shift. During a five month period, costs for 1935 lb of treating agent for the 1400 lb of dust and the transportation of both to an approved landfill totaled more than $76,000. "With the high costs, it was fortunate that we found RMT to provide another method of handling our wastes," said Pusa.

Acme became familiar with RMT, Inc., an engineering and environmental management services firm, through the American Foundrymen's Society. We chose RMT because of their proprietary Emission Dust Additive Process (EDAP), their ability to work with the regulatory agency and help us prepare the paperwork for presentation of the system to the agency, and for documentation of treatment effectiveness," said Pusa. 'In addition, they were able to test our wastes in their inhouse laboratory facility and coordinate their services with GMD equipment," he added. In a joint effort, RMT and GMD Engineered Systems, Inc., a manufacturing contractor, integrated EDAP with GMD's TETS for Acme Foundry.

"EDAP/TETS is a totally enclosed treatment system that involves injecting an additive into the ductwork upstream of the baghouse, which stabilizes the metals such as lead and cadmium in the waste," said Steve Streblow, a senior project engineer for RMT.

"Since the treatment additives are injected into the ductwork upstream of the point where the solid particles are settled out as wastes, EDAP/TETS is considered a process modification by the state of Kansas, and, therefore, the system is exempt from RCRA permit requirements."

Prior to the installation of EDAP/TETS, the cupola baghouse dust was classified as hazardous for the characteristic of toxicity for lead.

The firststep in developing EDAP/TETS was to have RMT perform bench-scale testing on the hazardous waste.

For the bench-scale testing, RMT developed a composite from the individual baghouse waste samples, using equal weights of each sample. "During the testing, subsamples of the composite dust were mixed with proprietary treatment additives, and TCLP tests were performed," said Bob Stanforth, senior applied chemist with RMT.

Based on the results of the bench-scale treatability testing, a target dosage of the optimum additives was chosen for field testing of the inline injection system.

The totally enclosed treatment system, manufactured by GMD, consists of storage for the dry treatment additives; powder screw feeders that meter the amount of additives to be injected into the system; a powder blower to transport the additives to the powder injection point; a powder injection nozzle (PIN), which thoroughly mixes the dry additives with all dust articles within the gas stream; and a control system to operate EDAP/TETS, with interlocks to Acme's existing control system.

While untreated foundry wastes are often variable in lead and cadmium content, the system is able to handle the variability and remain effective in meeting the specified treatment levels," said Stanforth.

For convenience, Acme Foundry houses its EDAP/TETS system in a separate building, which is located outside the main foundry and below the cupola baghouse system structure. "This system uses standard, industrial-duty equipment that has been designed with automatic controls and appropriate control interlocks," explained Streblow.

Acme's EDAP/TET's was operational in mid-February, five months after the initial testing, which included a four-week period during which Acme examined scrap charges and tried some variations in an attempt to lower the lead and cadmium levels. TCLP testing showed lead and cadmium levels in the dust to be far below the land ban requirements of 5.0 mg/l of lead and 1.0 mg/l of cadmium.

"Wastes discharged from EDAP/TETS also exhibit low leaching characteristics when subjected to a water leaching test," added Streblow. "We think the water leaching test more accurately depicts the leaching conditions in a foundry monofill, since these fills are usually nonacidic. Our experience with other treatment methods has shown that it is possible to treat a waste to meet TCLP treatment requirements, while the same waste will leach lead at levels above 5.0 mg/l during a water leaching test.

RMT petitioned the state of Kansas, on behalf of Acme Foundry, to remove the company from the list of firms that generate hazardous waste. An overview document and field test by RMT at Acme Foundry were submitted to Kansas officials for consideration. Based upon RMT's studies, the state approved EDAP/TEIS and officially terminated the foundry's status as a hazardous waste generator, in about four weeks.

By being classified solely as a nonhazardous waste generator, we have greatly reduced our liability and saved a lot of money and headaches,' said Pusa. We no longer have to train our employees how to handle and dispose of hazardous wastes; emergency procedures are simpler; we have less regulatory documentation to maintain, and our image in the community is enhanced because we no longer generate hazardous waste, he said.

Since the waste is nonhazardous based on treatment test results, Acme Foundry is again able to dispose the waste at its private landfill site and is in control of its waste management plans.

We have already paid for EDAP/TETS in the amount of money we have saved on hazardous waste treatment and disposal," added Pusa.