Background:
The Allen Bradley Site in Fairfield, New Jersey is the former leased location of a specialty electronics manufacturing facility. Rockwell International purchased Allen Bradley in 1985 and the site was closed in 1994. Subsequently the site was converted into a school for emotionally disturbed children. In September 1997 Rockwell retained an environmental consulting firm, Vectre Corporation of Lafayette, New Jersey, to review work performed by a previous consultant, and to advise Rockwell on what actions were necessary to mitigate potential environmental hazards at the Allen Bradley site.

Vectre conducted a detailed Remedial Investigation of the site which suggested that septic wastewater injected into an on-site dry well had produced TCE and DNAPL contamination in a plume about 20 feet below the surface which threatened a nearby stream. They also concluded that the previous site characterization had been inadequate, and that the natural attenuation and pump and treat options previously considered would not satisfy Rockwell's desire to expedite the site clean up. The existing database failed to adequately characterize source areas, vertical concentration gradients, or health and safety issues. After completing the investigation, Vectre concluded that a permeable reactive barrier was both an appropriate technical solution and the most responsive way to satisfy Rockwell's objective, which was to ensure that the site was remediated in a timely and economical manner that satisfied all health, safety and ecological issues.

Permeable Reactive Barrier Technology Overview:
Permeable Reactive Barriers are an effective, cost effective method for the passive remediation of dissolved groundwater contamination. This technology is gaining acceptance in the regulated community and is currently deployed as full or pilot scale applications in over fifteen states. The technology involves the placement of a reactive media into the subsurface where it will intercept the flow path of a groundwater contaminant plume. Groundwater is allowed to passively flow through the reactive media. As the contaminant comes into contact with the reactive media it is degraded, precipitated or sorbed. The design, monitoring and understanding of the reactions within the system is critical to a successful application. Knowledge of the site-specific conditions including a complete site characterization, determination of subsurface geology and identification of a suitable reactive media are necessary for deployment.

The ITRC formed the Permeable Reactive Barriers Team two years ago when the technology became a priority among the ITRC states and federal partners. During the first year the team developed a regulatory guidance document entitled "Regulatory Guidance for Permeable Barrier Walls Designed to Remediate Chlorinated Solvents" in addition to reviewing the US Air Force Document entitled "Design Guidance for Application of Permeable Barriers to Remediate Dissolved Chlorinated Solvents". Both documents have now been finalized and distributed [to the ITRC participating states] for ITRC consensus.

Remediation Review and Approval:
Rockwell, Vectre and the New Jersey Department of Environmental Protection (NJDEP) held a technical meeting in Trenton on May 19, 1998 to discuss the Allen Bradley site. Prior to the meeting, Matt Turner, an employee of NJDEP and also the ITRC Team Leader for Permeable Reactive Barriers, provided the NJDEP attendees with copies of the ITRC Guidance Documents. Attendees at this meeting included Mark Ishihara, Rockwell project manager, Steve Tappert, the lead consultant for Vectre Corporation, and Rob Lux and John Kosher from NJDEP. Rob Lux is the state geologist for this site. John Kosher is the sire remediation Program Manager. As background for the meeting Steve Tappert submitted an outline for a remedial strategy which included excavation of the DNAPL and the use of a reactive wall for containment and treatment of dissolved contamination. The type of reactive wall they were considering was a "funnel and gate" system.

During the meeting the advantages and disadvantages of both funnel and gate and continuous reactive walls were discussed. At that time the NJDEP attendees offered Rockwell/Vectre the ITRC guidance documents as a resource to assist in the decision process, design of the chosen system, and design of the ground water monitoring program.

Steve Tappert was familiar with permeable reactive barrier technologies, but had not previously done one himself. In Steve's own words: "The initial meeting with the NJDEP in May resulted in my first introduction to the ITRC documents. Recognizing that the NJDEP, through Matt Turner, had participated in the development of the guidance documents I surmised that it would be prudent to examine the documents closely and incorporate applicable aspects to the project at hand."

In July 1998 Rockwell/Vectre submitted a Remedial Action Workplan (RAW) to NJDEP which proposed excavation of the DNAPL area and back filling with a mixture of reactive iron and sand. They proposed to address the dissolved contamination using a continuous reactive wall 127 feet long, 5 feet wide, and 16-25 feet deep. Verbal approval to construct the system was given by the end of July. The review of the RAW was generally very straightforward for several reasons: a very thorough soil and ground water investigation was performed; there was favorable geology and distribution of the contaminants; and the application of a technology, while technically complex in terms of reactions and emplacement, was also fundamentally easy to understand and visualize.

Summary of Benefits:
Treatment of the DNAPL area and installation of the continuous reactive wall were completed in mid-August 1998, several weeks before school resumed at the site. Both Steve Tappert and Rob Lux credit the ITRC Permeable Barrier Wall Regulatory and Design Guidance Documents with significantly contributing to this expedited and successful site cleanup process, as the following comments indicate.

Rob Lux, State Geologist:
"It should be clear …that the key person in this case so far has been Steve Tappert of Vectre Corp. He came to the Department with the proposal for a reactive wall and addressed our concerns concerning source areas. His proposals were straightforward and well documented. It was hoped that by supplying the ITRC documents his job would be easier and that the Department would receive a high quality product. Certainly the latter was true but I cannot speak to the former."

Steve Tappert, Environmental Consultant:
" Finishing the job before school started was absolutely critical - the next window of opportunity would have been the following summer, which may have allowed high concentrations of contaminants to reach a major sewer interceptor in the street. When we started the project there was considerable skepticism that it could be completed within the allotted timeframe, and it took great cooperation from NJDEP to do it."

"The whole process - design through installation - took less than four months. That level of accelerated review is based upon a common pool of knowledge provided in the ITRC documents. Some of the confidence behind that [expedited] approach was due to the knowledge that our recommendation was basically consistent with the ITRC documents. The design document was somewhat useful in shifting our focus to a continuous wall rather than a funnel-and-gate (which ultimately saved time during the review process and cost during construction). I certainly used the monitoring design presented in those documents because I had an added degree of confidence that the proposed program would be accepted."

Mark Ishihara, Rockwell Program Manager
"Rockwell Automation's main objective for this site is to complete the remediation of the groundwater in a timely and economical manner in order to satisfy the NJDEP, the site owners, site tenants, neighbors and our stockholders. Additionally, we needed to complete the installation of the remediation system before the start of school this past fall. We were concerned that any delays in the approval of our selected design system would prevent us from completing the installation in time causing concerns for all our stakeholders and increasing the costs of the system. With the cooperation of the NJDEP and VECTRE, we were able to meet this installation objective."

Matt Turner, ITRC Permeable Barrier Team Leader
Permeable reactive barriers offer several advantages over conventional technologies such as a pump and treat system. For instance, reactive barriers are a passive in situ remedy with minimal operation and maintenance costs and no energy requirements. While this technology has been deployed full scale at a number of sites in the United States, it is still the subject of research and technology verification projects.

Cost Comparison for Selected Remedy and Most Likely Alternative

The state review and approval process for the Allen Bradley site took less than 3 months. This is the second site where NJDEP has approved use of permeable reactive barrier technology. First use of this technology in New Jersey was at the Caldwell Trucking CERCLA site in Fairfield, New Jersey, and the review took about 15 months. First use of this technology in Massachusetts (at a former manufactured gas plant) took over a year. The third use of this technology in Colorado, took 10 months.

This rapid and effective site remediation was of special significance to the Gramon School. As the site tenant and therefore a major stakeholder in the process they were anxious to assure that construction activity at the site would not interfere with school operations.

David Weeks, Director of the Gramon School:
" I was aware that this was a relatively new technology and that Steve Tappert had somehow been able to get it on a "fast track" with the regulators. I didn't at all appreciate the high level of teamwork and cooperation that went into the project until I read this study.

"Steve and Lee, his associate at Vectre, kept me regularly informed of both the planning and the implementation of the project. Moreover, whenever I appeared at the site, either one or the other was there at my side to explain what was going on and to ask if I had any concerns.

"From our perspective, Steve's ability to plan and execute the project on such a tight schedule was nothing short of miraculous! We were able to open school on time in September without missing a beat. Rockwell International must also receive high marks for its willingness to "go the extra mile" in responding to our concerns both promptly and generously."

Who to Contact for Additional Information:

Marybeth P. Brenner, ITRC State Point-of-Contact
New Jersey Department of Environmental Protection
401 East State Street, POB 409
Trenton, NJ 08625
Phone: 609-292-6877
Fax: 609-292-7340
e-mail: mbrennner@dep.state.nj.us

Rob Lux , Case Geologist
New Jersey Department of Environmental Protection
401 East State Street, POB 409
Trenton, NJ 08625
Phone: (609) 292-1998
e-mail: rlux@dep.state.nj.us

Matt Turner, Permeable Reactive Barrier ITRC Team Leader
New Jersey Department of Environmental Protection
401 East State Street
Trenton, NJ 08625
Phone: 609-984-1742
Fax: 609-633-1454
e-mail: mturner@dep.state.nj.us

Steve Tappert, Environmental Consultant
Vectre Corporation
15 State Route 15
Lafayette, NJ 07848-2007
Phone: (973) 383-2500 Ext. 26
Fax: (973) 579-0025
e-mail: set@vectre.com

Mark Ishihara, Project Manager
Rockwell Automation
1201 S. Second Street
Milwaukee, WI 53204
Phone: (414) 382-2566
e-mail: mrishihara@ra.rockwell.com

Dr. David Weeks, Director
The Gramon School
24 Dwight Pl.
Fairfield, NJ 07004-3304
Phone: 973-808-9555
Fax: 973-227-8626
e-mail: dweeks@idt.net

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