General Excavating - Environmental Services

Project:
Firth Cooperative
Underground Storage
Tank Remediation

Owner/Client:
Firth Cooperative
Mr. Ron Preston, Manager
3rd and Main Streets
P.O. Box 278
Firth, NE 68358
(402) 791-5837

Type of Waste / Contaminant:
Free Product and Dissolved Gasoline/Diesel

Scope of Work:
Soil Vapor Extraction System and Groundwater Pump and Treat System to clean up fuel contamination from both underground and above-ground storage tank leaks. The leaks were separate occurrences, requiring a second system be built to tie into the initial system with upgrades.
Initial System (Construction in 1994): Installation of 27 recovery wells, 17 of which were dual-phase air and water recovery. Combination of trenching and hand-digging 1200 LF of connecting piping. Boring of 180 feet under the street. Construction of a slab-on-grade 12 FT by 20 FT remediation building to house air-stripper, air compressor, SVE blower, oil/water separator, and controls. Installation of 27 manholes and lids (32-inch diameter). Installation of 27 groundwater pumps and individual controls. Electrical and plumbing for entire system. Excavation and disposal of 350 cubic yards of contaminated soil. Concrete replacement and other surface restoration.
System Addition (Construction in 1995-96): Modification of an existing monitoring well to become a dual-phase recovery well and a soil vapor extraction well. Project required manhole installation, pipe retrofitting, concrete pad, installation of 500 LF of 1-inch galvanized pipe, 500 LF of PVC pipe, and 10 LF of 8-inch PVC pipe. Excavation and disposal of 200 cubic yards of contaminated soil was required. Installation of a new product storage tank and associated piping for decanted fuel was utilized.

Method of Construction:
Backhoe for soil excavation, open cutting of trenches, directional boring under streeets and existing utilities, Well construction by a subcontractor using a bucket auger rig.
Benefit to Client:
Met installation deadlines for the Nebraska Department of Environmental Quality.
Conclusion:
Project completed on time and budget without accidents or safety problems. Firth