South Jersey Clothing Company Superfund Site Remediation
Minotola, New Jersey
Date of Execution: February 23, 1999
Description of Project
The SJCC manufactured military clothing from 1940 to 1982. In the later years, dry cleaning equipment discharged TCE onto the property which migrated to the groundwater table and create a plume on the shallow and intermediate aquifers. The plume extended for over 1 mile.
Sevenson performed work under multiple contracts at the site. The first contract involved the ACM abatement and demolition of the existing manufacturing buildings to prepare for the construction and operation of groundwater and soil remediation systems to remove TCE/PCE from groundwater and vadose zone soils. As a result of the pre-construction engineering survey, several areas of the plant were deemed unsafe, including failing roof support members and unstable basement walls. Sevenson revised its work plans and SSHP to account for these additional hazards by adding administrative and engineering controls to mitigate accidents or injuries.
During the ACM abatement phase of work, Sevenson implemented daily QC inspections as a means of managing productivity and to ensure that safe work practices were employed. A result of implementing this procedure was successfully completing this phase 50 days ahead of schedule despite additional work associated with previously unknown ACM identification.
The demolition of the manufacturing facilities was accomplished using traditional civil construction equipment (track excavator with grapple attachment). The demolition of the SJCC buildings included the removal of foundations to a depth of six feet. The basement floor slab was broken in-place to allow for water drainage, backfilled with certified clean fill and compacted using a vibratory roller to 90% maximum Proctor Density. Upon completion of debris removal, the site was graded to prevent ponding and stormwater run-off in accordance with the site Soil Erosion and Sediment Control plan.
The southern wall of one SJCC manufacturing building was only 18 feet away from an adjacent residence. There was valid concern that the demolition action could cause debris to damage the house. Prior to commencing demolition activities, Sevenson developed a “buttress” bracing system at five critical locations along the building’s southern wall to ensure that demolition methods would result in building debris falling in-place, mitigating damage to the residence.
Construction, start-up and short-term O&M of the 650 gpm groundwater recovery and the treatment systems was required under contract 2. Fifteen extraction wells were installed in the shallow and intermediate aquifers and twelve injection wells were installed in the upper aquifer to ensure 99.9% recapture of injected water as required in the NJDEP permit. Additional monitoring wells were installed to monitor for potential mounding of the shallow groundwater aquifer in areas adjacent to nearby residences.
Groundwater and soil treatment systems included vapor and liquid phase GAC units, upflow sand filter, gravity settler, two-chamber air stripper, chemical treatment (acid, caustic, KmnO4, and polymer), and soil vapor extraction wells. During treatment system construction, Sevenson assigned additional site superintendents to assist subcontractors during critical construction activities. These were seasonal individuals who had experience in building and pipeline construction. This provided Sevenson’s subcontractors valuable guidance and direction.
Sevenson installed 1.5 miles of dual-wall (extraction) and single-wall (injection) force mains throughout the Borough of Buena’s roads and property. Several actions were instituted to mitigate disruption with on-going businesses as well as maintain the safety of both project personnel and residents. Actions included establishment of traffic controls; scheduling work at busy intersections to avoid congestion and the increased potential risk of accidents; and work in the vicinity of an elementary school was conducted over weekends to mitigate any risks to school children.
Since a significant portion of the work took place in an active area of town, a high degree of coordination among Sevenson’s labor forces, local municipal officials and affected residents was required. Sevenson’s Project Manager conducted operations and safety briefings throughout the duration of the project with municipal officials, including local emergency responders, to ensure that all work was carried out safely and responders were aware of the potential hazards associated with responding to potential incidents at the site. Sevenson also maintained close communication with municipal officials regarding the sequence of work activities to ensure minimal interruption local businesses and residents.
Treatment System Operation
The SJCC system is designed to remove VOCs (primarily TCE and PCE) from the aquifers beneath the facility and the surrounding community south of the former SJCC plant. The SJCC treatment system, with an average annual operating cost of $800,000, consists of:
- Extraction well collection of GW from shallow and intermediate depth wells via a dual containment force main to a 60,000 gallon equalization tank.
- Addition of KMnO4 to aid in iron removal.
- Gravity settlement and removal of solids and particulates through sand filters. Solids and particulates are captured in a sludge holding tank then dewatered via plate-and-frame filter press prior to shipment for off-site disposal.
- Dual column air strippers to remove VOCs from the process water stream.
- Liquid-phase GAC treatment of the process water as a final VOC polishing step.
- Re-injection of the treated effluent into a 12-well gallery upgradient of the treatment facility.
- SVE remediation of contaminated vadose zone soils using a vapor-phase GAC system.
- Vapor-phase GAC treatment of SVE and process air streams adsorbs VOCs for regeneration/disposal.
The injection gallery includes a series of groundwater monitoring wells with remote sensors that feed into the system PLC. In the event that mounding of the groundwater occurs (which would impact several nearby residences) the PLC will either reduce flows through the treatment system or shut the system down.
Sevenson’s efforts to optimize treatment system efficiency has included:
- Elimination of the KMnO4 addition system - since there is little iron (hardness) in the extracted groundwater requiring treatment. The manganese levels in the groundwater actually increased as a result of KMnO4 addition.
- Repositioning of extraction well pumps to optimize contaminated groundwater removal and redevelopment/cleaning of injection wells increased discharge volumes by 20%.
- Balancing of extraction well withdrawal rates to maximize flows from higher contaminated wells increased the average VOC removal from 25 ppb to 250 ppb in the process stream.
- During base year operations, Sevenson utilized the services of a Team Member to provide several system refinements, including upgrade of SCADA system hardware and software. These included:
- Installation and configuration of peripheral data storage and backup devices to ensure data system operations integrity in the event of a power failure.
- Programming and calibration of PLCs and Human Machine Interfaces (HMI) software to improve accuracy of system performance monitoring.
- Enhance data management and reporting functions.
- Upgrade system alarm recognition functions to improve monitoring capabilities and avoid unnecessary plant shut-downs.
- Develop global system enablement command logic to significantly reduce start-up time.
- Improvement of existing graphical interface screens and development of additional interface screens.
- Addition of remote monitoring and control access to facilitate off-site programming and support activities.
These refinements improved treatment system management, reliability, and performance, as well as reduce operating costs by $35,000 per year.
Treatment Systems Start-up
Completion of the construction contract included transition training and the development of as-built drawings and the facility O&M manual. Site operations staff were brought on-board as part of system start-up and shakedown. This aided in problem troubleshooting and identification of corrective actions during system prove-out.
Sevenson's on-site staff includes one Project (N4) Supervisor and one Plant Operator who provide on-site management on an 8-hour, 5 day per week basis. Operational problems during unmanned periods result in the system auto-dialer calling the Project Supervisor, then the Plant Operator. Through a dial-up connection, the Project Supervisor can review every aspect of the treatment plant remotely, identify the reason(s) the alarm was tripped, as well as reset certain system components to restart the plant. When the Plant Supervisor in not available, the Plant Operator can assume these responsibilities.