Commercial property building demolition followed by remediation
Active was asked to assist in a remediation project at a commercial property. Active began with the demolition and removal of an automotive repair garage so the work area could be accessed. The site had a long history of impact that was identified to an extent of approximately 30 feet below ground surface over a widespread area. Groundwater was identified to be approximately 15 feet which posed the first issue.
To access the work area and depth, Active established a dewater system that pumped approximately 3 million gallons of water from the work area over the duration of the project. Over the course of this project, Active removed and disposed of approximately 800 tons of impacted soil while stockpiling the remaining clean fill to be used as backfill.
To remove the final 10 feet of impacted soil Active created cells and drove sheeting to minimize the amount of groundwater flow into the excavation which allowed the dewatering pumps to keep up. Being almost 30 feet below the surface and at a minimum of 15 feet into the groundwater table, managing groundwater at this depth was a challenge, however with the sheeting it made the work easy to complete.
Prior to backfilling the excavation Active placed approximately 2,000 pounds of in-situ bio remedial enhancement agent to assist in the remediation of the groundwater. The site was backfilled in one-foot lifts and completed back at the original surface grade.
Active received a call from a client asking if we could help with identifying a suspected UST in the basement of a commercial property. Active begin with our in-house Geophysicist identifying and marking out the UST location. It was identified at this point that the UST appeared to be a 1,000 gallon tank. Upon completion of the identification, Active returned to the site to collect soil samples from around and through the bottom of the UST. Sample results indicated that there were detections over standard and that the UST and impacted soil were going to need to be removed. Two major concerns with the project were vapors from the UST disrupting the business and structural support. To eliminate the vapor issue, Active created a containment around the work area under negative pressure and vented the work area 150 feet to the rear of the building, thus eliminating any indoor air quality issues. Once that was established, an engineer designed structural support and the Active team went to work. As material was excavated from the work area around the UST the structural support was constructed. All material was removed by hand and the UST was cut in pieces and removed. All impacted soil was staged and later disposed of at an off-site disposal facility. The UST was recycled. Upon approval from the client, Active backfilled the excavation with flowable fill utilizing a pump truck. All the work was performed during normal business hours without any interruption to the businesses.
This project consisted of impacted soil in a wetland area. Prior to any start of work, Active worked closely with a wetland expert and the client to establish a game plan that was cost effective and efficient all working within the sensitivity of being in an ecological sensitive area that had been identified as a wetland area. Clearing and grubbing was established to access the work area. All nonnative species were carefully removed in order to prevent any spreading of those species. As this was bring performed Active had established E&S controls to mitigate any sort of erosion during the clearing and grubbing. Once completed, Active began with the remediation work. Active removed and disposed of approximately 1,400 tons of impacted soil while stockpiling and relocating approximately 2,100 tons of for onsite reuse during future development. Upon completion, Active completed the project with seeding, planting and landscaping.
Active was contracted to assist in the closure of two regulated tanks at a former gasoline station. Active’s specialized team expertly managed the removal and disposal of two 10,000 gallon steel wrapped fiberglass underground storage tanks (USTs) at a former gasoline station. Active’s team started with a thorough site assessment to confirm utilities identified by our in-house geophysicist, site safety, and work area access for traffic and equipment. Active began by safely excavating to the top of the UST’s to uncover and gain access to remove any remaining residual liquids. Once all liquids were removed, the team set up a nitrogen cradle to purge the tanks for safe access into the tanks for final cleaning prior to removal. Active preformed consistent safety monitoring while performing the cutting and cleaning of the tanks. Once a safe environment was established and access in to the inside of the tanks was established the team entered the tanks under a confine space entry permit and performed the final cleaning prior to removal. Once the tanks were removed, our team assisted in regulatory sampling followed by the backfilling of the former UST locations with certified clean fill. No additional remediation work was needed at this time. The USTs were recycled at a certified recycling facility to complete the project.
Recently, we completed an Underground Storage Tank (UST) removal and soil remediation project in New Jersey and thought it might be of value to share our process and expertise to provide insight on how we consistently complete challenging projects for our clients with a smile and a high level of integrity. THE PROJECT During initial conversations with the client we firmly understood that this would be an interesting and challenging project but one where our experience would allow us to shine and create a positive outcome. The site was a former commercial bus depot and the 10,000 gallon UST was originally assumed to be constructed of fiberglass. However, when we arrived on site and began the work, we immediately identified that the UST was constructed of steel and not fiberglass. The weight of the steel tank - they’re often around 4 times the weight of their fiberglass counterparts – meant that the project approach was going to need to be changed. Fortunately, we’re a dynamic firm that thrives on adapting to change and taking on challenging projects. In fact, we gained a strong reputation early on for accepting jobs that other firms either couldn’t figure out or deemed “too difficult”. For us, it was just another great day of “Challenge accepted!” and we knew we were going to create a great experience for the client. OUR PROCESS Accessing & Cleaning the UST Before breaking ground, we secured all necessary State and local permits and completed a public utility mark out as required by law through the New Jersey One Call notification system. The New Jersey One Call system only marks public utilities and as there was significant potential of encountering private utilities in the work area, we contracted with a private utility locating company to complete a geophysical investigation. This firm identified the boundary of the UST as well as other potential unmarked utilities and subsurface fixtures. As part of our company commitment to the safety of our clients, crews and the surrounding areas we work in, we always take that extra step to make sure any potential safety issues are unidentified before any work begins. Once all pre-mobilization permitting, utility location, and general site safety checklists were completed, we utilized our excavation equipment to uncover the top of the UST in order to gain safe access for the removal of bulk liquids and tank entry for cleaning work. We initially removed fittings on the exposed portion of the tank and utilized our vacuum truck to remove the remaining free liquids. Once complete, we utilized and LEL meter to check the tank for potentially life threatening hazards such as a lack of oxygen or explosive atmosphere and completed purging and inerting as needed to ensure it was safe to cut open and enter the tank for cleaning. A confined space entry retrieval system was set up and while continuously monitoring the tank atmosphere the tank was entered & cleaned. Once cleaning was complete, the UST was ready for removal. Removal Before removing a tank from the ground, the soils surrounding it need to be excavated so the tank can be safely removed. Once the cleaned tank is removed from the excavation, it can then be transported off-site to a recycling facility for processing and beneficial reuse, which is one benefit of steel tanks. As many tanks as we have removed during our 27 years in business, I always wondered if they come back as cars, refrigerators or countless other useful items after the recycling process but I guess we will never know. The downside to using steel tanks is that they are very susceptible to rust and corrosion, which potentially leads large scale environmental impacts and public health issues. Soil Remediation Once the UST was removed, the tank carcass is inspected for evidence of corrosions holes, seam failures and general age-related decay that indicates a potential release may have occurred. Additionally, the bottom and sidewalls of the excavation are inspected for any evidence of a discharge such as soil staining or petroleum odors that might indicate a potential impact to the surrounding soils. In this case, the client already completed a soil investigation and determined that a release had in fact occurred and soil contamination was identified outside the footprint of the UST. Having this information available prior to initiating the tank removal activities allowed us to be well prepared to complete the required remedial activities in the most cost-effective manner. We immediately removed and stockpiled contaminated soils, stockpiling it on and covering it with heavy plastic sheeting. Once all of the impacted soils were removed and staged, the next step was to load the impacted soils and transport the material to an approved and properly permitted facility for disposal and beneficial reuse. As the impacted soils were being transported off-site for disposal, certified clean fill material was delivered to the site and used to backfill the excavation. During the backfilling process, we mechanically compacted the fill material to prevent future settling of the excavated area. Modified stone was added on top of the back fill and compacted and graded in order to create a safe and drivable area for the client’s continued operations. The fieldwork for the entire project was competently managed and successfully completed by Active’s Senior Foreman Jayson Richards and Tony Salange. Voila! Project Complete. If you suspect a UST leak or if your site requires remediation services, don’t hesitate to contact us . We strive to get the job done on time, on budget and to create a positive experience for all of our clients; leaving every project site better than we found it.