Avisco was contracted for the demolition of building foundations and the removal of process sewer piping, sanitary and storm sewer pipe along with contaminated soil at a former uranium processing plant and TNT/DNT manufacturing facility which covers over 50 acres. Work was preparatory to constructing an on-site disposal cell. Major operations included: removal and placement of 457,000 cubic yards of rad/chemical contaminated concrete and soils in adjacent storage areas constructed on site; 39,000 linear feet of underground piping; the placement of 57,000 cubic yards of low-permeable soil; 64,000 cubic yards of structural embankment; and 95,000 cubic yards of miscellaneous fill soil for the construction of the landfill cell. The project also included removal of 155,000 cubic yards of clean soil that was unsuitable for the future landfill; accurate daily surveys of the irregular shaped contaminant plumes; characterization and remediation of mercury contaminated drains; removal of contaminated soils; miscellaneous asbestos abatement; construction of haul roads and temporary and permanent access roads; development and maintenance of temporary staging areas; removal of underground skimmer and fuel storage tanks; removal of electrical conduit and lead sheathed cable; removal of asphalt pavement; removal of PCB-contaminated concrete; development of a borrow area and associated sediment controls; 30 acres of storage area; and implementation of extensive dust controls to contain radioactive airborne particles.
Avisco developed a borrow area and associated haul road for the remediation of Solid Waste Storage Area (SWSA) 4 Burial Ground and Intermediate Holding Pond (IHP). SWSA 4 was performed as a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remedial action. The selected remedial action for SWSA 4 was hydraulic isolation with a multi-layered cap, which included an up-gradient diversion trench and a down-gradient collection trench, and excavation of contaminated soils, sediment and vegetation from the IHP. Major work items for this phase of work included erosion control measures, installation of corrugated metal pipe, basin excavation, construction of entrance and access roads, fence repair, clearing and grubbing, stone base and installation of traffic control signs.
Avisco, Inc. performed a project to remediate the four seepage basins that were once used by the Savannah River Laboratory (SRL). The basins consisted of four unlined earthen pits that received low-level radioactive waste water from the SRL. The basins were located adjacent to each other and are connected through a series of sequential overflow channels. The activities performed included erosion and sedimentation control measures, clearing and grubbing, dewatering, contaminated soil removal, packaging and shipping of contaminated soil to an off-site disposal facility, fencing, compacted backfill, final grading and permanent seeding of the finished basin fill area, storm water drainage control systems, and access roads.
Avisco, Inc. constructed a soil vapor extraction system designed to remediate an old burning pit located in C-Area of the DOE Savannah River Site. The work consisted of constructing a low-permeability clay cap, installing 28 air injection wells and 28 soil vapor extraction wells, concrete equipment pads, installing the associated air compressor and vapor extraction equipment, a propane fueled incinerator, the necessary piping and electrical systems and general site preparation. This project was constructed under the strict requirements of DOE and met all the requirements imposed by the South Carolina Department of Health and Environmental Control.
The S-3 Ponds Pathway 2 Treatment System (P2TS) was constructed by Avisco to passively treat contaminated groundwater extracted from a french drain located west of the former S-3 Ponds site. The project site is located at DOE’s Y-12 Plant, Oak Ridge, Tennessee. This CERCLA project consisted of the installation of an additional 125 ft French drain, and extraction well for the French drain, a 750 ft siphon drain line, two shallow treatment boxes, a drain field, reinstallation of a monitoring well, and associated valves, instrumentation, and treatment media.
Avisco, Inc. was contracted to construct a vertical interceptor drain system to depths of 27 feet along contaminant plumes leading into Mitchell Branch and a vertical interceptor drain 23 feet deep along the base of the K-1070 C/D Burial Grounds to deter the flow of contaminated groundwater. The trenches were excavated to the top of bedrock using a Bio-Polymer Slurry to provide hydrostatic pressure on the narrow, unstable trench walls. The HDPE panels were installed through the slurry and connected using HDPE interlocks welded to each panel. The trenches were backfilled with select drainage stone on the up-gradient side. Submersible pumps and HDPE Force Main piping were installed to transfer the contaminated groundwater to the wastewater treatment plant, Central Neutralization Facility. Other aspects of this project included boring and jacking a 12" casing pipe under an existing railroad track, installation of extraction wells and piezometers, installation of a 38,000 pound oil/water phase separator, and constructing approximately 800 linear feet of stream channelization with articulated block pavers along Mitchell Branch.
Avisco remediated petroleum contaminated soils caused by a leaking underground pipe at a fuel storage facility on the Tennessee ANG Base in Knoxville. The project entailed working around underground gas, electrical and jet fuel lines, many of which were live during the excavation and required shoring until clean dirt was returned.
Avisco remediated the site known as Elza Gate under the FUSRAP program used during the Manhattan Project in the 1940s. The site originally consisted of five warehouses and other smaller structures used to store uranium ore (pitchblende) and processed residues. Avisco selectively excavated contaminated soil and concrete from a building and surrounding grounds while allowing production to continue at an existing manufacturing facility at the site.
Avisco, Inc. installed a dual-contained HDPE leachate collection piping system, dual-contained HDPE manholes, lift station and a storage facility to contain and transfer several hazardous chemicals leaching from this DOE. The contaminants identified in the excavations included volatiles, semi-volatiles, vinyl chloride and radioactive leachate. Some work had to be accomplished at Level "B". All personnel had to be fit tested for respirators. Continuous air monitoring, sampling, testing and analyses were conducted to insure limited exposure to hazardous substances including high levels of radiation. Equipment had to be decontaminated prior to leaving, therefore decontamination pads were constructed and mobile steam pressure washers were provided on site
Avisco, Inc. started this project by selectively clearing a one mile right-of-way for an access road around the K-901-A pond. Work crews were informed of the potential for finding hazardous debris, cylinders, and drums along the route. Avisco constructed the access road, a PVC lined burial cell for internment of contaminated fish, a staging area for cylinders, and a decontamination area. The pond was drained and a rip-rap access pier was constructed on the pond bottom to allow a trackhoe, equipped with a hydraulic grappling thumb, to reach the entire pond depression. The trackhoe sifted through the silty sediment to dislodge and remove hazardous cylinders, drums, and debris. All debris removal was performed in Level “B” protection using supplied air carried on the trackhoe. Cylinders and drums were pressure washed, and characterized by qualified personnel in the Decon area.
This was the first Superfund site on Chattanooga Creek to be remediate. The site consisted of ceramic debris contaminated with heavy metals which had been pushed into a wetland. Avisco, Inc. excavated and hauled the heavy metal contaminated soil from the wetlands and encapsulated the contaminants in low permeable clay. Low ground pressure equipment was utilized to place the heavy metal contaminated soil and low permeable clay into the disposal area. Access to and from the site was difficult and required coordination of traffic in order to perform the work in a timely manner.