Williams Hill Redevelopment Area, Subsurface Investigation and Remediation, St. Paul, Minnesota
 
DPRA, under contract with the St. Paul Port Authority, performed a soil and groundwater investigation and cleanup at this 31-acre site. Sources of contamination identified included historical railroads, former city dump, asphalt production, and stockpiles of concrete, crushed aggregate, asphalt, and borrow material. DPRA installed monitoring wells, excavated numerous test pits and trenches, and conducted extensive vapor and groundwater receptor surveys. DPRA conducted groundwater modeling to evaluate the potential impact to the nearby Mississippi River and establish site-specific cleanup goals. Lead-contaminated soils were stabilized on site and managed as non-hazardous, significantly reducing cleanup costs.

City of Barstow Waste Water Treatment Plant Discharge Investigation, Barstow, California.

The City of Barstow operates a waste water treatment plant (WWTP) along the southern bank of the Mojave River. Elevated nitrates found in drinking water at a nearby neighborhood prompted a large scale investigation overseen by the Regional Water Board.  Nitrogen and oxygen isotope analysis performed by DPRA’s laboratory, Zymax Forensics, has provided evidence that denitrification is occurring in and around the WWTP facility and aided in delineating the lateral and vertical extents of discharges.
 
Site Investigation and Expert Witness Testimony, ExxonMobil Property, St. Paul, Minnesota
 
DPRA collected detailed field data and provided expert witness testimony to assist the St. Paul Housing and Redevelopment Authority (HRA) obtain a favorable ruling from the Ramsey County District Court regarding the sale through eminent domain of the ExxonMobil property located in St. Paul, Minnesota. A key part of the trial presentation involved the computer animation of site stratigraphy, including representation of existing and proposed monitoring wells, recovery wells, and vapor extraction ports. This presentation provided the court with a visual means of understanding the subsurface conditions in a manner that was comprehensive and clear.
Former Dry Cleaner Site Investigation and Remediation, Sunstone Hotel Investors, Rochester, MN
 
DPRA performed comprehensive due diligence, subsurface investigation, and remediation on the site of a former retail laundry and dry cleaning facility adjacent to the Mayo Clinic. DPRA installed a dual-phase extraction system which removed nearly 300 pounds of PCE and significantly reduced the dissolved PCE concentrations in the groundwater. DPRA submitted reimbursement applications for the client to the MPCA Dry Cleaner Fund and the client received reimbursement for all investigation and cleanup activities at the site. Based on DPRA’s investigation, the City of Rochester proceeded with site purchase and redevelopment.