Attachment 8 - Excavation Contaminated Mat.doc

Attachment 8

DTFAAC-15-R-02838

EXCAVATION AND HANDLING OF CONTAMINATED MATERIAL

3.0 Execution

3.1 EXISTING STRUCTURES AND UTILITIES

No excavation shall be performed until site utilities have been field located. Contracting Officer’s Technical Representative (COTR)/Resident Engineer (RE) shall mark all utilities in excavation area. The Contractor shall take the necessary precautions to ensure no damage occurs to existing structures and utilities. Utilities encountered that were not previously shown or otherwise located shall not be disturbed without approval from the Resident Engineer.

3.2 CLEARING

Clearing shall be performed to the limits shown on the drawings or as directed by the Resident Engineer.

3.3 CONTAMINATED MATERIAL REMOVAL

3.3.1 Excavation

Areas of potential contamination shall be excavated to the depth and extent shown on the drawings or as directed by the Resident Engineer. Excavation shall be performed in a manner that will limit spills and the potential for contaminated material to be mixed with uncontaminated material. An excavation log describing visible signs of contamination encountered shall be maintained for each area of excavation.

3.3.2 Shoring

If workers must enter the excavation, it shall be evaluated, shored, sloped or braced as required by 29 CFR 1926 section 650.

3.3.3 Dewatering

Surface water shall be diverted to prevent entry into the excavation. Dewatering shall be limited to that necessary to assure adequate access, a safe excavation, prevent the spread of contamination, and to ensure that compaction requirements can be met.

3.4 CONFIRMATION SAMPLING AND ANALYSIS

The Resident Engineer shall be present to inspect the removal of contaminated material from each site. After all material suspected of being contaminated has been removed, the excavation shall be examined for evidence of contamination. Field analysis shall be used to determine the presence of contamination. Excavation of additional material shall be as directed by the Resident Engineer. After all suspected contaminated material is removed, confirmation samples shall be collected and analyzed in accordance with regulatory and permit requirements. A minimum of one sample shall be collected from the bottom of the excavation. Based on test results, the Contractor shall propose any additional excavation that may be required to remove material which is contaminated above action levels. Additional excavation shall be subject to approval by the Resident Engineer. Locations of samples shall be marked in the field and documented on the as-built drawings or provided in a separate report.

3.5 CONTAMINATED MATERIAL STORAGE

Material shall be placed in temporary storage immediately after excavation. The following paragraphs describe acceptable methods of material storage. Storage units shall be in good condition and constructed of materials that are compatible with the material or liquid to be stored. If multiple storage units are required, each unit shall be clearly labeled with an identification number and a written log shall be kept to track the source of contaminated material in each temporary storage unit.

3.5.1 Stockpiles

Stockpiles shall be constructed to isolate stored contaminated material from the environment. The maximum stockpile size shall be 200 cubic yards. Stockpiles shall be constructed to include:

▪ A chemically resistant liner free of holes and other damage. The ground surface on which the liner is to be placed shall be free of rocks greater than 0.5 inches in diameter and any other object which could damage the membrane.

▪ Cover free of holes or other damage to prevent precipitation from entering the stockpile. The cover material shall be extended over the berms and anchored or ballasted to prevent it from being removed or damaged by wind.

▪ Berms surrounding the stockpile, a minimum of 8 inches in height. Vehicle access points shall also be bermed.

▪ The liner system shall be sloped to allow collection of leachate. Storage and removal of liquid that collects in the stockpile, shall be in accordance with paragraph Liquid Storage.

3.5.2 Roll-Off Units

Roll-off units used to temporarily store contaminated material shall be water tight. A cover shall be placed over the units to prevent precipitation from contacting the stored material. Liquid that collects inside the units shall be removed and stored in accordance with paragraph Liquid Storage.

3.5.3 Liquid Storage

Liquid collected from excavations and stockpiles shall be temporarily stored in 500-gallon polyethylene tanks provided by the contractor. Liquid storage containers shall be water-tight and shall be located near the stockpile areas.

3.6 SAMPLING

3.6.1 Sampling of Solid Material

Samples of stored material shall be collected at a frequency sufficient to meet the requirements of approved disposal facilities. Samples shall be tested in accordance with regulatory and disposal facility permit requirements.

Stored material with contaminant levels that exceed action levels shall be treated or disposed offsite. Analyses for contaminated material to be taken to an offsite treatment facility shall conform to local, state, and federal criteria as well as to the requirements of the treatment facility. Documentation of all analyses performed shall be furnished to the Resident Engineer. Additional sampling and analyses to the extent required by the approved offsite treatment, storage, or disposal (TSD) facility shall be approved by the Resident Engineer.

3.6.2 Sampling Liquid

Liquid collected from excavations and stockpile leachates shall be sampled at a frequency of once for every 500 gallons of liquid collected. Samples shall be tested in accordance with regulatory and permit requirements.

Liquid with contaminant levels that exceed action levels shall be treated or disposed offsite. Analyses for contaminated liquid to be taken to an offsite treatment facility shall conform to local, state, and federal criteria as well as to the requirements of the treatment facility. Documentation of all analyses performed shall be furnished to the Resident Engineer. Additional sampling and analysis to the extent required by the approved offsite TSD facility receiving the material shall be the responsibility of the Contractor and shall be subject to approval by the Resident Engineer.

3.7 SPILLS

In the event of a spill or release of a hazardous substance (as designated in 40 CFR 302), pollutant, contaminant, or oil (as governed by the Oil Pollution Act (OPA), 33 U.S.C. 2701 et seq.), the Contractor shall notify the Resident Engineer immediately. If the spill exceeds the reporting threshold set by the State and/or EPA, the Contractor shall follow the pre-established procedures as described in the Facility Contingency Plan for immediate reporting and containment. Immediate containment actions shall be taken to minimize the effect of any spill or leak. Cleanup shall be in accordance with applicable federal, state, and local regulations. As directed by the Resident Engineer, additional sampling and testing shall be performed to verify spills have been cleaned up

3.8 BACKFILLING

3.8.1 Confirmation Test Results

Excavations shall be backfilled immediately after all contaminated materials have been removed and confirmation test results have been approved. Backfill shall be placed and compacted to the lines and grades shown on the drawings.

3.8.2 Compaction

Approved backfill shall be placed in lifts with a maximum loose thickness of 12 inches. Soil shall be compacted to 90 percent of maximum dry density.

3.9 CLOSURE REPORT

Three copies of a Closure Report shall be prepared and submitted within 30 calender days of completing work at the site. The report shall be labeled with the contract number, project name, location, date, and the name of general contractor. The Closure Report shall include the following information as a minimum:

▪ A cover letter signed by a responsible company official certifying that all services involved have been performed in accordance with the terms and conditions of the contract documents and regulatory requirements.

▪ A narrative report including, but not limited to, the following:

− site conditions;

− excavation logs;

− field screening readings;

− quantity of materials removed from each area of contamination;

− quantity of water/product removed during dewatering;

− waste disposal manifests

− sampling locations and sampling methods;

− sample collection data such as time of collection and method of preservation;

− sample chain-of-custody forms; and

− source of backfill.

Include the following:

▪ Copies of all chemical and physical test results.

▪ Copies of all manifests and land disposal restriction notifications.

▪ Copies of all certifications of final disposal signed by the responsible disposal facility official.

▪ Field drawings showing limits of each excavation, limits of contamination, known underground utilities within 20 feet of excavation, sample locations, and sample identification numbers. On-site stockpile, storage, treatment, loading, and disposal areas shall also be shown on the drawings.

8/27/07