Background Information:
This site is located in South Buffalo, adjacent to the Buffalo River. New York State Department of Environmental Conservation (NYSDEC) had determined that cleanup requirements for the project have been achieved. The Buffalo Color Corporation (BCC) chemical and dye plant consisted of numerous process, administrative, maintenance buildings, process equipment, and chemical storage tanks prior to remediation. The plant produced over 1,000 different dyes and organic chemicals based on aniline and aniline derivatives from 1879 to 1977. Demolition of these structures took place in 2011 by South Buffalo Development, LLC. The remediation work was complete in 2013, including work performed by Geo-Solutions. The planned future reuse for this site is commercial and light industrial.
Project Objectives:
The project design included a contiguous hydraulic barrier wall combining slurry wall & jet-grout techniques, encircling impacted groundwater within Area A. Also, an existing water intake structure located adjacent to the Buffalo River required decommissioning. This decommissioning required installation of concrete headwalls and grouting with controlled low-strength materials (CLSM) to seal the water flow from entering the site. This work was completed first, and then the hydraulic barrier wall was constructed through the CLSM and keyed into the underlying clay strata to facilitate a groundwater pump and treat system, installed and maintained by others after barrier wall installation.
Description of Work:
Although the design included 20,000 vertical square feet (VSF) of slurry wall and over 13,000 square feet of jet-grouted barrier wall, Geo-Solutions was able to re-proportion the units to construct 28,150 VSF of Slag-Cement-Bentonite slurry wall and only 6,370 VSF of jet-grouted wall, thus saving the client significant money. The barrier wall was carried to deeper elevations in several locations where the clay confining zone was deeper. Geo-Solutons conducted an extensive mix design program to achieve a significantly lower hydraulic conductivity in the barrier wall performance. The structural stability of the wall was also increased several orders of magnitude above the minimum design, allowing greater flexibility for future land-use considerations. The Slag-Cement-Bentonite hydraulic barrier wall was completed with a CAT 385 hydraulic excavator and Geo-Solutions’ specialty boom and stick attachment capable of excavating to a depth of 60 feet below ground surface elevation. A Geo-Solutions-designed reagent batch plant provided the self-hardening slurries for hydraulic barrier wall construction.
The New York State Department of Environmental Conservation (DEC) determined the cleanup requirements to address contamination related to the Buffalo Color Corporation Site Area A, under New York State’s Brownfield Cleanup Program. The cleanup activities were performed with oversight provided by DEC. DEC approved a Final Engineering Report and issued a Certificate of Completion for the site.
Various structures are present on Area A, including former BCC Building 75 (single-story masonry structure), the groundwater extraction system treatment building (single-story metal clad building), and several other metal-clad structures. The balance of Area A is now covered with a soil cover system, an asphalt paved parking lot, site entrance, and gravel pavement. The site and surrounding area topography is now generally flat but with an embankment leading to the edge of the Buffalo River. The site and area surrounding the site is generally zoned for heavy industry. The nearest residential areas are located approximately 1,000 feet north of the site.
The river originally came through this parcel of the site before the site was backfilled and the intake structure needed to be filled in order to keep the river water from mobilizing the existing subsurface contamination in Area A. Personnel worked in the mouth of the structure, near river water level, with pneumatic tools to install reinforcement steel dowels in the existing concrete and erected sacrificial concrete formwork prior to placing the cast-in-place concrete for the bulkheads. Vertical holes were drilled above this intake structure from the ground surface and 330 cubic yards of self-hardening flowable fill (controlled low-strength material) were used to seal-up the vault below. The slag-cement bentonite vertical hydraulic barrier wall was subsequently installed with the long-stick excavator through the area to form a contiguous site barrier, connecting to the jet-grout barrier wall, preventing off-site migration of impacted groundwater and confining the impacted groundwater for the subsequent pump-and-treat system. Marine diving equipment and suits were needed for construction. Underwater video camera equipment was utilized to verify successful construction of the headwalls.
