Underground Storage Tank Removal or UST Abandonment
Underground storage tank removal is the technical process of excavating tanks from below the ground surface, in accordance with environmental laws and standards. In fact, this process requires regulatory oversight, special licencing contractors, geological evaluation and environmental compliance. Furthermore, the process generates hazardous waste on record. As a result, all UST removal projects require disposal documentation and certification. Additionally, confirmation soil sampling is a requirement by the government, before back filling can occur. This is to assure the necessity of further remediation before the burial process commences. Updated April 23, 2019.
Underground Storage Tank Removal, Excavation & Earthwork
Special licencing excavators, hygienists, geologists and engineers are a requirement to legally remove underground tanks. In most cases, excavators will try to simplify the removal process, by ramping the sidewalls of an excavation pit. In fact, this method is not only cheaper, but safer. However, some projects have complex conditions, and additionally require a geotechnical specialist for proper lateral support, shoring. Ultimately, this requirement will base on the requirements of local building and grading department codes.
Additionally, crane operators and welders with special certifications are occasionally required to safely extract the tanks from the subsurface. Moreover, field personnel have various state and OSHA certifications to be onsite during dig-out projects. Hazardous waste transportation in this case requires proper licensing, and all disposal or treatment facilities must have government registration and approval. Lastly, professional engineers must certify the back-filling materials undergo proper compaction.
Typical Procedure for Underground Storage Tank Removal Projects
The UST abandonment process includes the following procedures:
- An application for Underground Storage Tank Removal including as-built plans and proposed excavation calculations.
- An approved permit by the local regulatory agency.
- Site specific health and safety plan.
- Specialized earthwork construction meeting all OSHA standards.
- Pre-demolition hazardous materials management and spill prevention.
- Proper planning for hazardous waste disposal and EPA Certification.
- Tank-hauling and truck-mounting for licensed transportation.
- Soil sampling.
- Laboratory analysis and environmental assessment report.
- Certified soil back-filling and compaction testing.
- Surface pavement.
Mandatory Environmental Testing
Government agencies require environmental soil sampling in the areas under each UST. This process is “confirmation soil sampling,” and occurs under the professional responsibility of a geologist or engineer. For instance, four to five soil samples are collected, and laboratory results apply to determine the possibility of a leak. Each agency administers it’s own action levels for underground storage tank removal projects. In theory, slight contamination is allowable. However, if concentrations exceed the action levels, remedial action will be a requirement by the agency. Soil contamination can be cleaned-up via impact source removal remediation.
Soil Contamination Excavation and Remediation
Typically, soil contamination remediation during UST removal projects occur in the form of a continuous dig-out and disposal. This cycle may repeat up to three or four times before the regulatory agency allows back-filling or closure. On the other hand, if the contamination is continuously apparent above action levels after multiple confirmation cycles, the agencies will allow back-filling, but not close the case. Consequently, the agency will likely require environmental site assessments and other methods of long-term remediation. For example, back-filling the pit, and then implementing soil vapor extraction to clean the deep contamination.
Geo Forward, Inc. is a leading provider of UST abandonment services in California. Call (888) 930-6604 and speak with a licensed geologist, engineer or contractor.
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