Ciba-Geigy Chemical Corporation Superfund Site, Operable Unit 2

Toms River, New Jersey

Date of Execution: April 2001

Significant Project Features:

• Sevenson was selected to provide Constructibility Review services during development of the RD.

• Remedial Design and Construction Management executed on a collaborative basis among Ciba-Geigy, its RD engineer and Sevenson.

• Multiple contracts for site work, building construction and remediation services are required to complete Operable Unit 2.

• Excavation, characterization, consolidation, transportation and disposal of 47,000 buried drums.

• Excavation, transfer and ex-situ bioremediation of 175,000 cy contaminated soils from multiple source areas is conducted in specialty structures using composting methodology.

Location and History of Project

Ciba-Geigy manufactured dyes, pigments, resins and epoxy additives on a 1,350 acre parcel between 1952 and 1990. Sludge and chemical process wastes were placed in drums and buried, or disposed in lagoons and other areas on the property. Groundwater and soil were contaminated primarily with volatile organic compounds (VOCs).

In 1983, the site was added to the National Priorities List. Between 1983 and the implementation of the remedial action requirements of Operable Unit 2, several important measures were implemented at the site. These included implementation of the groundwater remedy required under OU1 as well as the development, implementation and completion of multiple investigations, engineering studies and preliminary design studies.

In 2000, Ciba-Geigy developed a statement of work to address the requirements of Operable Unit 2. The objective was to identify a firm with the ability to assist Ciba and its design engineer, as a team member, to participate in an ongoing Constructibility Review to develop the final plans and specifications. Sevenson was awarded this contract in 2001. The contract included construction management responsibilities for all remedial action requirements under OU2. Sevenson worked closely with both Ciba and its design engineer through 2003 when the project was ready to move to implementation. Each phase of the subsequent remedial actions was competitively bid to Ciba-Geigy.

Project Description

Thus far, Sevenson's field work has centered around three (3) OU2 activities. These are:

Site Work Contract - This contract required Sevenson to prepare the site and coordinate site activities for all planned remedial actions under OU2. Site work included clearing and grubbing; construction of all access roads; installation of storm water controls; and preparations of work areas for the construction of three (3) treatment buildings which will house bioremediation operations. This initial site work and building construction work took 6 months to complete.

Buried Drum Removal - Sevenson excavated over 47,000 drums from a lined disposal area that was used between 1972 and 1977. The drums contained both hazardous and non-hazardous materials. The original number of drums was estimated to be 32,000. Drums were excavated, inspected, characterized, segregated and removed. Drum materials were consolidated into roll off boxes and moved off-site for treatment and/or disposal.

Bioremediation Operations - Operable Unit 2 remediation activity includes the excavation and bioremediation treatment of excavated soils. Sevenson is currently excavating 175,000 cy of contaminated soil and sludge from seven (7) source areas: Backfilled Lagoon Area, Borrow Compactor Area, Building 108 Area, Equalization Basins, Former South Dye Area, Filtercake Disposal Area, and Drum Disposal Area. Soil is excavated and staged at the biotreatment facility. Soil excavated from source areas is replaced with treated material or onsite borrow. Air monitoring is conducted during all operations. At the Former South Dye, Filtercake Disposal and Drum Disposal areas, slurry walls and vertical drains and caps for infiltration barriers will be constructed to confine these areas estimated to be 25 acres.

Ciba-Geigy, with assistance from its RD engineer and Sevenson, developed the ex-situ biotreatment "recipe." Sevenson is implementing processes and procedures to treat soil using windrow composting bioremediation. Soil is excavated, staged, screened and stored, then mixed with a ratio of soil, straw, wood chips, nutrients, water and oxygen. A compost mixer (Allu) is used to aerate and turn the soil mixture to increase contaminant break down. After several weeks, soil is moved to a secondary treatment area where treatment with water and aeration continues. When treated materials passes a leaching test the soil is considered treated. The treated soils are used as backfill in areas scheduled to be capped as remedial actions under OU2 future contracts.

Health and Safety Overview

Sevenson developed a Health and Safety Contingency Plan (HSCP) to address any impacts to public health, safety, and the environment. An extensive air monitoring plan was included in the HSCP. The plan included baseline air monitoring, perimeter air monitoring, work-zone air monitoring (during bioremediation, soil and material excavation and drum handling) and post-excavation air monitoring.

All work was performed to minimize the risk of exposure to the constituents of concern including organic contaminants. Workers were trained and instructed on proper work safety, PPE levels, decontamination, and emergency procedures.

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