Superfund Site Remediation

"Remediating a Chemical Manufacturing Site"

What's the most effective way to design a groundwater treatment system for a Superfund site, without disrupting the facility's operations?

MWH tackled this challenge for the Chemplex Superfund site in Iowa. Our experts conducted remedial investigations for the chemical manufacturing site, and later designed a groundwater extraction and treatment system. During the installation of the system, our staff also managed the construction activities.

Three-dimensional Hydrogeologic Model

MWH's remedial investigation included subsurface investigation and testing of the complex fractured carbonate aquifer (mainly Silurian Systems). This provided valuable data for the design of the groundwater extraction and treatment systems.

Remedial investigations had shown that light and dense nonaqueous phase liquids (LNAPLs and DNAPLs), as well as petroleum products, chlorinated solvents and polynuclear aromatic hydrocarbons had been detected in the groundwater. MWH maintained close regulatory contact for the client with EPA Region VII and Iowa Department of Natural Resources.

MWH's remedial design featured an extraction and conveyance system, as well as a treatment system. Our professionals developed a 3-D hydrogeologic model that simulated aquifer response to natural and induced conditions. This helped MWH select the location of 51 remedial extraction wells and their associated pumping rates.

The new treatment system collects LNAPL and DNAPL, in addition to treating extracted groundwater for dissolved constituents. Components of the treatment systems include iron removal, air stripping, granular activated carbon (GAC) and catalytic oxidation of the off-gas from the air strippers.

Ongoing Monitoring

The groundwater extraction and treatment system is fully automated. This minimizes the risk of operator oversight as well as the need for interface with a busy facility.

MWH continues to provide ongoing monitoring of the extraction wells, and annual ground water sampling.