Underground Storage Tank Removal
Does your property contain an underground storage tank (UST) that needs to be removed? Let Rubidium Environmental’s experts assist you with overseeing the removal of the tank and verifying that soil and/or groundwater in the vicinity of the tank are not impacted.
What is an Underground Storage Tank?
An underground storage tank is a below grade cylindrical vessel and any associated underground piping that is used to store and transfer liquid materials. The presence of USTs is indicated by the presence of fill ports that are generally flush with the ground surface and vent pipes that are located above grade. Underground storage tanks can vary in size and are commonly used for the storage of fuel oil, gasoline, diesel, and solvents.
Why are Underground Storage Tanks a Concern?
Prior to the mid-1980s, a majority of USTs were made of uncoated mild steel, which is highly likely to corrode over a period of time. As the storage tank rusts away, this allows the contents of the tank to escape and discharge into the surrounding soil and/or ground water. In addition, a majority of underground storage tanks were installed directly onto the ground surface and the use of a secondary containment unit was not implemented. Without secondary containment, leaks from the tanks begin to contaminant the neighbouring soil, and potentially the groundwater.
If contamination is expected or detected from an underground storage tank, it should be removed and remediated prior to causing further subsurface contamination. The presence, or potential presence of underground storage tanks are common sources of soil contamination in Ontario. If during a Phase 1 Environmental Site Assessment, an underground storage tank is expected, a Phase 2 Environmental Site Assessment is recommended to assess the potential extent of contamination in the vicinity of the tank caused by any leaks and/or spills.
Who Controls the Use of Underground Storage Tanks?
USTs used to store petroleum products are controlled by provincial regulations. In Ontario, the Technical Standards and Safety Authority (TSSA) regulates USTs containing petroleum products, while the MOEC oversees any off-Site contamination (if identified).
Commonly, underground storage tank removal activities are conducted in compliance with the TSSA Protocol for Environmental Management for Fuel Handling Sites (2007), the Canadian Council of Ministers of the Environment (CCME) Environmental Code of Practice for Underground Storage Tanks Containing Petroleum Products, and the applicable Site Condition Standards.
What are the components of an underground storage tank Removal?
In order to remove a UST, a qualified and experienced environmental contractor is retained to conduct the underground storage tank removal. Removal of the tank generally requires excavation of the property, and the area around the tank. Often it is most economical to combine the underground storage tank removal, and soil and groundwater remediation services during the same process. Rubidium Environmental supports the UST removal through Environmental Site Assessment inspections and oversight during the underground storage tank removal process, and by conducting the verification soil and groundwater sampling program. The TSSA requires documentation of the activities, and Rubidium has experience in preparation of the necessary reports.
Why Is Underground Storage Tank Removal Important?
Early detection of a UST leak and/or spill, identifying the source of the release, and assessing the soil and/or groundwater in the vicinity of the tank are important. In order to identify the source of the release and verify the amount of liquids released into the environment, a tank and associated piping must be inspected and subsequently removed. Generally, a tank tightness test is conducted to verify and/or refute if a leak is occurring. Upon confirmation of a leak, the source of the release must be minimized and the potential risks to the environment must be reduced immediately. Leaking USTs can have impacts on the property value, drinking water wells, and the build-up of vapours in underground structures in close proximity of the UST can cause human health and safety impacts.
The initial phase of the underground storage tank removal commences with the removal of the remaining tank contents and purging of any vapours. Once the tank is deemed “clean”, soil and groundwater remediation is performed starting with the excavation of the area in the vicinity of the tank. Generally, soil is stockpiled on-site and classified (through soil sampling and laboratory analyses) as re-usable material or material that needs to be disposed of off-site. Once the tank and piping are exposed, the piping is disconnected and removed, followed by the removal of the tank. Once the UST has been excavated from the tank nest, the tank is punctured, sheared and disposed of off-site at a licensed landfill. Subsequently, confirmatory soil sampling is conducted on the walls and floor of the former tank nest to confirm that no soil impacts are present. If there is evidence of potential impacts to groundwater, then confirmation groundwater samples must be collected and submitted for laboratory analyses. Upon receipt of analytical results that comply with the applicable Site Condition Standards, the excavated area is backfilled, graded, and restored. Should soil and/or groundwater impacts be detected during the confirmatory soil sampling and testing program, a soil and groundwater remediation action plan is compiled and the impacted area is remediated accordingly.
Upon completion of the underground storage tank removal and successful soil sampling program, a report is provided to the Client and the TSSA for regulatory review and compliance.