Research Projects

Project at a Glance

Title: An innovative integrated systems approach to non-incineration destruction of benzene, VOCs and odors from metal casting operations. Final report

Principal Investigator / Author(s): Lewallen, Steve

Contractor: Gregg Industries

Contract Number: ICAT 02-307

Research Program Area: Emissions Monitoring & Control

Topic Areas: ICAT Grants / Technology, Stationary Sources


The casting operations of all foundries may produce odor-causing compounds, volatile organic compounds (VOCs) and particulate matter. The majority of the emissions of concern come from two operations in the casting process: core making and sand handling. In the core making process, new sand is mixed with resins - phenolic, phenolic-urethane, etc. - and cured to form resin-bound sand forms (cores) that are used to create open spaces in the molds that result in the ability to make hollow castings. The majority of the resins generate odors during the core making, core curing and metal casting processes. Sand handling operations, which include mixing, molding, casting, pouring, cooling and shakeout, can also generate odors, particulate matter and VOCs. The odors generated by foundries in populated areas have led to an increasing number of nuisance complaints. Gregg Industries, Inc., and iron casting foundry in El Monte, California, had seen a continued increase in odor-related complaints, totaling almost 200 per year prior to this project. To reduce or eliminate these complaints, Gregg Industries and its parent organization, Neenah Foundry Company of Neenah Wisconsin sought an innovative technology that would control odor-causing compounds and reduce VOC emissions.

Furness-Newburge, Inc. had developed Sonoperoxone, an advanced oxidation system that treats the water used in sand mixing/mulling and sand cooling operations of greensand foundries with a combination of high powered acoustics and additions of ozone and hydrogen peroxide. Advanced oxidants react with the clays and coals of greensand to reduce harmful emissions and to recycle clays and coal from particulate collected from dust collectors. VOC reductions of up to 74 percent, benzene reductions of up to 64 percent, and clay usage reductions of up to 43 percent have been reported at foundries using the Sonoperoxone process. Furness-NewBurge had also developed a wet scrubber system to remove pollutants and destroy odors from core-making operations. The scrubber uses UV light and advanced oxidant enhanced water to remove the pollutants and odor causing compounds, then regenerates the water with the Sonoperoxone process. This project is the first time the innovative Sonoperoxone Clay Recycle and Odor Scrubber Systems were integrated, installed and demonstrated at the commercial-scale in an operating foundry.

The objectives of this demonstration project were to determine 1) the effectiveness of the Sonoperoxone Scrubber in reducing odors and VOCs from gaseous effluents generated from core making and sand handling operations and 2) the overall technical and economic feasibility of the integrated system, specifically whether the savings from the use of the Sonoperoxone System in sand handling operations can justify the cost of the odor and VOC scrubbing technology.

The following tests were performed: 1) a series of background tests to identify the foundry operating conditions (sand system conditions) that produce the maximum odor intensity; 2) a series of baseline tests to identify VOC and odor causing compound concentration; 3) a series of tests to evaluate the operating sand system conditions following installation of the Sonoperoxone scrubber system; and 4) a series of tests to determine the effectiveness of the Sonoperoxone scrubber system at reducing VOC and odor causing compound concentrations.

The conclusions from the project are:

* The Sonoperoxone scrubber system is an effective odor control/VOC reduction technology for reducing emissions. The AQMD considers a level five times the threshold of detection as the point where the odor becomes an annoyance. That technology litmus test was exceeded only once (by phenol) in all the testing completed, missing the target by two percent. Improvements planned for the core room scrubber system will further reduce the final phenol levels.

* Odor complaints dropped from roughly 200 per year before the Sonoperoxone scrubber system was installed to two since installation. AQMD determined that these two complaints were not related to operations at Gregg Industries.

* In-plant smoke and odors have been reduced dramatically as a result of installing the Sonoperoxone scrubber system.

* Casting quality has improved, scrap rates have dropped, and sand, clay and coal purchases and use are down, resulting in significant savings and operating costs.

* The savings realized have already paid for the entire system.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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