2537.01 SCOPE OF WORK.

A. Removal of Underground Tanks.
Removal of underground tanks shall include:

1. Removal, collection, and disposal of contents of the tank system.

2. Vent, remove, transport, and destroy all components of the tank system.

3. Obtain and test soil and groundwater samples necessary to complete Iowa DNR's Tank Closure Report.

4. Furnish, install, maintain, and subsequently remove safety fence enclosure around excavated areas.

5. Remove non-contaminated soil and rubble.

6. Furnish, place, compact, and finish to grade the excavation with suitable backfill soil.

7. Prepare and provide Tank Closure Reports to the Engineer.

B. Remediation of Petroleum Contaminated Soil.
Remediation of petroleum contaminated soil shall include:

1. Removal of contamination by excavating a specified volume of soil.

2. Transport, spread, incorporate and turn contaminated soil at remediation areas designated or approved by the Engineer, or transport and dispose of contaminated soil at an approved solid waste landfill.

3. Obtain and test soil and groundwater samples necessary to complete Iowa DNR's requirements for removal of contaminated soil by excavation.

4. Furnish, place, compact, and finish to grade the excavation with suitable backfill soil.

5. Prepare and provide an Over-Excavation of Contaminated Soil report to the Engineer.

In situations where suitable remediation sites are not available within the ROW, the contract documents will require delivery of petroleum contaminated soil to a solid waste landfill facility approved by the Engineer.

All work shall be in accordance with 567 IAC, Chapters 120 and 135, applicable OSHA regulations, and this specification.

2537.02 DEFINITIONS.

For the purposes of this Specification the following definitions will apply:

A. Contamination.
Contamination or contaminated shall mean the presence of petroleum hydrocarbon constituents at concentration levels at or above those listed in Iowa DNR's Tier 1 Look-Up Table in 567 IAC, Chapter 135. Soils with constituent concentrations below these levels will be classified "non-contaminated."

B. Destroy.
Destroy shall mean rendering a tank system unusable for any purpose other than scrap metal or landfill material in the case of plastics or fiberglass. All components of a system shall be cut-up and/or crushed prior to being recycled as scrap or landfilled.

C. Land Application.
Land application shall mean the act or process of placing, leveling to a uniform thickness and application rate, incorporation, and remediation of petroleum contaminated soil to a level of constituent concentration less than those listed in the Tier 1 Look-Up Table in 567 IAC, Chapter 135. Land application and land farming are terms which are often used interchangeably.

D. Incorporation.
Incorporation means the process of mixing the contaminated soil after placement to provide a loose and divided soil texture and leveling at the remediation site. Mixing operations such as disking or harrowing to approximately 2 inches (50 mm) greater than the depth of material placed are considered acceptable.

E. Remediation of Contaminated Soil.
Remediation of contaminated soil means the process of removing contaminated soil by excavation, surface applying the contaminated soil in a relatively thin layer, and allowing natural processes to reduce contamination levels below regulated action levels. Once contaminated soil has been land applied, it must remain in place until the levels of contamination are below those listed in the Tier 1 Look-Up Table in 567 IAC, Chapter 135.

F. Tank System.
Tank System means underground storage tanks and all associated piping, auxiliary equipment, containment systems and leak detection equipment. A tank system includes, but is not limited to: fill and vent piping, product delivery piping, product pumps, product dispensers, leak detection piping, and leak detection wells.

2537.03 NOTIFICATION.
Based on the Contractor's work schedule, the Engineer will complete necessary Iowa DNR regulatory notifications for tank removals and additional excavation for petroleum contaminated soil.

A. Removal of Underground Tanks.
The contractor shall provide written notification to the Engineer 45 calendar days prior to removing underground tanks. The Engineer will provide the 30 calendar day Iowa DNR written pre-tank-removal notification.

B. Remediation of Petroleum Contaminated Soil.
The Contractor shall provide and submit the Iowa DNR's "Land Application Notification" form to the Iowa DNR with a copy sent to the Engineer at least 30 calendar days prior to beginning excavation activities.

The Engineer will waive this ten calendar day notification if:

1. Petroleum contaminated soil will be taken to an approved solid waste landfill.

2. Yhe remediation notification was separately identified and included with the 45 calendar day notification for removal of underground tanks.

3. The excavated material will be stockpiled, pending further remediation activities. In this case, submission of the Iowa DNR notification will be required at least 30 calendar days prior to removing the soil from the stockpile for land application.

2537.04 LOCATION.

A. Removal of Underground Tanks.
The location of all known underground tanks will be identified in the contract documents. Should the Contractor encounter an underground tank system that is not identified in the contract documents, the Contractor shall stop all activities in close proximity of the discovery, promptly notify the Engineer of the discovery, and not resume work in the immediate area until authorized by the Engineer.

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B. Remediation of Petroleum Contaminated Soil.
The location for an excavation and any Engineer-designated remediation area, or approved solid waste landfill will be designated in the contract documents. The Contractor may propose an alternate remediation area, subject to the requirements of 567 IAC, Chapter 120 and the Engineer's approval. Contaminated soil shall be stored, applied, incorporated, and turned in accordance with the landfarm operating requirements in 567 IAC, Chapter 120. If a remediation area is located within a designated borrow or staged construction area, the Contractor shall coordinate with the other project contractors and be prepared to stage land application operations so the remediation area remains available for construction project requirements. The contract documents may contain other specific containment requirements.

2537.05 UNDERGROUND TANK REMOVAL.

A. Removal of Tank Contents.
Prior to tank removal:

1. All liquid, sludge, and/or sand shall be removed from the tank system, collected, and disposed of in accordance with Federal, State, and local regulations.

2. Tanks shall be vented and purged to reduce vapors below explosive levels.

B. Removal of Underground Tanks.
Underground Tank Removal shall include the removal and destruction of the tank, all associated piping, and auxiliary equipment.

2537.06 EXCAVATION, BACKFILL, AND SAFETY FENCE.

A. Removal of Underground Tanks.
Excavation required for underground tank removal shall be the excavation necessary to remove the tank including all original backfill that was placed when the tank was installed, and excavation necessary to remove piping associated with the underground tank system.

The Contractor shall immediately notify the Engineer if excavated material contains suspected contamination pursuant to 567 IAC 135.6. Excavated material that has petroleum contamination shall be remediated as described in this specification. All other sand fill, rubble, and materials associated with tank removal shall become the property of the Contractor and removed from the project in accordance with Article 1104.08.

B. Remediation of Petroleum Contaminated Soil.
Approximate limits of excavation (horizontal and vertical) will be identified in the contract documents. Actual excavation limits will be determined in the field and based on the extent of contaminant migration. Excavation shall continue until Organic Vapor Monitoring (OVM) readings and laboratory tests indicate remaining soil is at, or below, Iowa DNR's Tier 1 Look-Up Table levels published in 567 IAC, Chapter 135, or when directed by the Engineer to stop.

In situations where petroleum contaminated soil is below a layer of non-contaminated soil, the Contractor shall remove and stockpile the non-contaminated soil before or during excavation of the contaminated area. Non-contaminated soil may be used for backfill material provided Type A compaction, in accordance with Section 2107, can be achieved. If non-contaminated excavated soil does not meet the requirements of Article 2102.06 or cannot achieve adequate compaction it shall become the property of the Contractor and removed from the project in accordance with Article 1104.08.

C. Backfilling Excavations.
The Contractor shall provide earth fill material for backfilling. This material shall meet the requirements of Article 2102.06.

Backfilling shall not begin until authorized to do so by the Engineer. The backfilling and compaction operation shall be completed according to the requirements of Section 2107 for Type A compaction, and shall be completed within ten working days after authorization is given.

The site shall be graded, shaped to drain, and left in a condition in accordance with Article 1104.08.

D. Safety Fence.
The Contractor shall furnish, place, maintain, and remove (after completing backfilling operations), safety fence meeting the requirements of Article 4188.03 around the site of work. Fencing material shall remain the property of the Contractor.