Conn-Selmer, Inc. Groundwater Remediation System
EPA ID No: AZT 000 612 135
Conn-Selmer, Inc. (CSI) (formerly United Musical Instruments, Inc.) operates a groundwater remediation system (GRS) at 1310 West Fairway Drive, Nogales, Arizona (see Figures 1 and 2). The GRS is designed to remove volatile organic compounds (VOCs) from the groundwater. The VOC contamination is the result of inappropriate storage of wastes during musical instrument manufacturing operations conducted from 1966 through 1985. The GRS is a "pump and treat system" and consists of pumping groundwater from an extraction well at the source of contamination to a 7,000-gallon equalization tank. Contaminated groundwater is then pumped at 50-75 gallons per minute (gpm) through two air stripper towers, in series. Each air stripper tower is 28 feet tall, and has an inside diameter of 3.5 feet. The air stripper towers contain packing material to maximize exposure of contaminated groundwater to air, introduced by fans countercurrent to water flow. The clean, treated groundwater is sent to Palo Duro Creek Golf Course for irrigation. A schematic of the GRS is presented in Figure 3. A photograph of the system is shown in Figure 4.
History of the Site
From 1966 through 2003, the facility was used to manufacture clarinets and trombones, and to assemble saxophones. In 1966, due to the lack of public wastewater processing plants near the facility's rural location, sanitary waste and industrial process water were treated on-site and directed to a 50 by 200 foot unlined surface impoundment in the northwest portion of the 8 acre property. Approximately 3,000 gallons per month of sanitary waste and industrial wastewater, primarily solvent rinse-water containing small amounts of trichlorethene (TCE) and 1,1,1-trichlorethane (1,1,1-TCA) were discharged to the surface impoundment from 1966 to 1985. A 1,200 gallon concrete tank was used to precipitate metals out of the wastewater from plating operations. Precipitated metals were shipped to smelting and refining companies. The remaining wastewater was treated with sodium hypochlorite to destroy residual cyanide and discharged to the surface impoundment. Excess wastewater from the surface impoundment was pumped to two smaller, unlined surface impoundments east of the production building.
On August 18, 1980, CSI's predecessor, C.G. Conn/Artley Flute, filed a notice of hazardous waste activity with the U.S. EPA as required under the federal Resource Conservation and Recovery Act (RCRA) for their Nogales, Arizona facility. On November 19, 1980, C.G. Conn/Artley Flute submitted a RCRA Part A Permit Application in order to continue to operate under interim status. To comply with interim status requirements under A.A.C. 18-8-265.A (40 CFR 265.90 et seq.), groundwater monitoring was begun. Analysis of ground water samples indicated that contaminants from the surface impoundment had leached through the soil into the groundwater. As a result, in 1985, the large unlined surface impoundment, the two smaller impoundments, and the wastewater treatment system were closed, excavated, and the contaminated soil removed. Final closure was conducted pursuant to a plan approved by ADEQ in December 1986. On February 01, 1988, ADEQ certified closure of the three surface impoundments and the wastewater treatment unit under RCRA and the Arizona Hazardous Waste Management Act (AHWMA).
To mitigate the adverse impacts to the groundwater, an extensive evaluation of groundwater remediation alternatives was conducted in the 1980s. ADEQ approved the use of a pump and treat system to remove the hazardous volatile organic compounds from extracted groundwater. In 1990, CSI's consultant, Woodward-Clyde, installed and evaluated the efficiency of two air strippers operating in series. In 1993, CSI entered into a consent order (#D-47-93) with ADEQ that required CSI to continue to monitor and remediate groundwater at the site. A second consent order (#Z-10-98) was signed with ADEQ, stemming from violations noted from a 1996 ADEQ site inspection of the facility.
The GRS has now operated continuously since 1998. The concentrations of contaminants at the center of the contamination have been reduced by 97 percent over twenty years (see Table 1). Initially, hazardous contaminant concentrations and degradation products in groundwater at the source were approximately 10,000 parts per billion (TCE and 1,1,1-TCA). By 2008, concentrations of those hazardous VOC contaminants in groundwater have been reduced to less than 250 parts per billion. Treated water leaving the GRS contains no VOCs, and is used for irrigation at the City of Nogales, Palo Duro Creek Golf Course.
The site operates under the hazardous waste Post-Closure Permit and the requirements of Consent Order, Z-10-98. The Post-Closure Permit allows CSI to continue to operate the GRS until they demonstrate that the health-based aquifer contaminant levels for VOCs and degradation products have been met.
Types of Hazardous Wastes (40 CFR § 261, Subpart C & D)
The contaminated groundwater, associated with the former surface impoundment, is currently being withdrawn from an extraction well (EW-2) and pumped through two air strippers in series to evaporate the VOCs from the water. VOCs detected in groundwater that exceeded established limits for drinking water include trichloroethene, 1,1,1-trichloroethane, and aerobic and anaerobic degradation products.
Quantities of Hazardous Waste Stored
The total quantity of spent halogenated solvents that were placed in the surface impoundments before 1985 is unknown. The quantity of hazardous constituents that may have migrated through the soil to the groundwater is also unknown. However, chemicals used and potentially discharged to the surface impoundment are identified in Attachment A, Exhibit A-3 of the draft permit. That inventory is the basis for the constituents that must be monitored by CSI during post closure. Metals constituents have not consistently exceeded the established regulatory limits. Therefore, ADEQ requires in the permit to have CSI analyze the groundwater for total metals on an annual basis, rather than semi-annually, until such a time that CSI begins final site closure.
Description of the Post-Closure Permit
The Post-Closure Permit consists of seven separate sections of text and their attachments. All conditions are based on the RCRA Part B Post-Closure Permit Application submitted December 31, 1997, with supplements and updates provided by the applicant until March, 2009. The permit establishes a post-closure care period of thirty years, beginning upon permit issuance. The term for the permit is for ten years. It will be renewed periodically by the applicant until the cleanup is complete.
The following are brief descriptions of the Permit Parts and their regulatory basis:
- Part I - General permit conditions required by Arizona Administrative Code (A.A.C.) R18-8-270 A and L and 40 CFR 270.30.
- Part II - Post-closure facility conditions required by A.A.C. R18-8-264.A and 40 CFR 270.32 and 264, Subpart H.
- Part III - Specific conditions related to the groundwater monitoring and remediation system required by A.A.C. R18-8-264.A and 40 CFR 264.100.
- Part IV - Specific conditions regarding inspections required by A.A.C. R18-8-264.A. and 40 CFR 264.195 (tank inspections), and 40 CFR 264.602 (miscellaneous unit inspections).
- Part V - Specific conditions regarding emergency response required by A.A.C. R18-8-264.A and 40 CFR 264 Subpart D (Contingency Plans and Emergency Procedures).
- Part VI - Specific conditions regarding record keeping required by A.A.C. R18-8-264.A and 40 CFR 264 Subpart E (operating record).
- Part VII - Conditions regarding corrective action required by A.A.C. R18-8-264.A and 40 CFR 264.101(corrective action for solid waste management units).
Other Permit-Related Documents
- Part A - Permit Application
- Part B - Permit Application, Section 1 of 5
- Part B - Permit Application, Section 2 of 5
- Part B - Permit Application, Section 3 of 5
- Part B - Permit Application, Section 4 of 5
- Part B - Permit Application, Section 5 of 5
ADEQ Response to Public Comments on the Conn-Selmer, Inc. Final Draft Post-Closure Permit
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