Carlhian Remediation on the Sudbury River

CommTank was hired by this customer to remove a 500-gallon underground storage tank and replace it with a 275-gallon Roth Tank. The tank was located under a patio in the back of the house. After taking out the underground tank, we found oil underneath it and a hole that was the size of a dime in the tank's bottom. The tank was at least 50 years old and had been leaking for some time.

The underground storage tank was removed and we tested the surrounding soil to determine the extent of the oil spill. Because the soil under the tank was clay (the house fronts the Sudbury River) the fastest method for recovering the oil was excavating the contaminated soils. Due to the sensitive nature of the waterfront property, an excavator could not be brought in to dig out the area. Instead it was done by hand over the summer months and the soil was moved to a container using a conveyor belt that passed through the house. The project was very unusual as the customer is the editor of the newsletter-Rhododendron Species in our Midst and an avid collector. Her gardens are also featured on the American Rhododendron Society Massachusetts Chapter web site. The grounds surrounding the house were covered in Rhododendrons and could not be disturbed. Excavating was done under the house, which presented issues of support. Many columns of concrete footings were built to support the areas that we exposed. The seasonal groundwater fluctuations required treatment of the water before it could be discharged. CommTank provided a water treatment system to handle this and discharged the clean water back to a dry well. Once the contamination was removed, the conveyor belt was used to bring crushed stone to fill the void under the house. To complete the restoration, a liquid flowable fill (a combination of fly ash, slag, and cement) was pumped through hoses into holes in the foundation floor.