In-Well Stripping Installation

at the 57th & N. Broadway Site, Wichita, Kansas

Setting	Wichita, Kansas 31-well full-scale installation TCE, DCE, and vinyl chloride contamination in one unconfined aquifer
Hydrogeology	Stratified aquifer: Seven feet of silty clay; 36 feet of poorly-graded to well-graded sands Hydraulic conductivity: 50 ft/day to 400 ft/day Plume thickness: 42 to 50 ft in upper unconfined aquifer Depth to groundwater: 7.4 to 12.8 ft
Contamination	TCE peak concentration: 11 mg/L DCE peak concentration: 10 mg/L Vinyl chloride peak concentration: 14 mg/L Primary Objective: Reduce TCE, DCE, and vinyl chloride concentrations below MCLs downgradient of treatment wells
Inorganic Chemistry	Groundwater is not in equilibrium with calcite, indicating little potential or calcite scale formation.
Operation Details	One 1.75 hp rotary vane pressure blower per well. Open-loop systems. No emission control required. Two piezometers for each well (62 total) and three monitoring wells to measure performance. Pumping rate: 5.1 to 19.4 gpm. Air/water ratio: 3.7:1 to 22:1 in five measured wells. System operation: In service since October 2001 with limited inspection. Routine maintenance of the mechanical systems. One blower repair for high temperature damage.

Monitoring results indicate MCLs are being achieved by the systems at the monitoring wells on the eastern two thirds of the main plume. All concentrations below or near MCLs. Fifteen systems shut off after one year.