FAST TRACK INSTALLATION AND OPERATION OF FULL SCALE IN SITU OZONATION SYSTEM AT A FORMER MGP SITE

摘要

A full-scale, in situ ozonation application to remediate soil and groundwater was implemented by MidAmerican Energy at a former manufactured gas plant (MGP) site in Dubuque, Iowa. Previous operation of the MGP facility resulted in the release of polycyclic aromatic hydrocarbons (PAHs) and hydrocarbon contaminants to soils and groundwater. This paper describes the fast track implementation of an ozone sparging system within a semi-confined aquifer, and the combined effects of chemical oxidation and bioremediation on the MGP contaminants. In-situ ozone sparging was initially field tested in a 3-month pilot study, then selected by MidAmerican Energy and USEPA for full-scale implementation for treatment of the silty sand aquifer on-site. Ozone sparging was selected as the technology to meet the conditions of the Record of Decision (ROD) based on its ability to oxidize high molecular weight PAHs such as benzo(a)pyrene while enhancing in situ aerobic bioremediation. Ozone is 12.5 times more soluble in water than oxygen, decomposes to oxygen as it reacts with contaminants, and can make some contaminants more available to indigenous aerobic bacteria.