Hodgdon Powder Company (Hodgdon) has manufactured propellant at their facility in central Kansas since 1979. The propellant is gunpowder that is a formulation of potassium perchlorate, potassium nitrate, sulfur, and charcoal that is an alternative to black powder. Subsurface contamination was identified which resulted from the permitted use of unlined wastewater lagoons. A Remedial Investigation (RI) at the site revealed a plume of perchlorate contamination in groundwater which extended over an area of several square miles with perchlorate identified in at least three separate fractured bedrock aquifers. Perchlorate contamination was also identified in surface water and on-site soils. Hodgdon provided a new potable water supply and distribution system to impacted rural residents in the area and entered into a Consent Agreement with the State of Kansas to address the perchlorate impacts.
Source-area and off-site evaluation of the extent of perchlorate impact
Hydrogeological characterization/aquifer testing
Remedial technology review
Bench-scale/pilot-scale testing of in-situ biological treatment amendments
Remediation management and groundwater monitoring oversight
Facility storm water management
Evaluation and correction of sewer infiltration and inflow issues
Water pollution control permitting
Remedial activities included implementation of IRM to achieve source-area cleanup of impacted soil. Enhanced biological reduction of perchlorate was successfully achieved in source-area soils via mixing of no-cost carbon-donor material from a neighboring cattle feed lot. This innovative remedial approach resulted in destruction of perchlorate to non-detectable levels and closure of source-area soil treatment cells within three years of implementation. This also represented the first time, on a national level, that perchlorate impacted soil had been successfully treated in this manner.
Interim remedial measures were also initiated to examine similar biological reduction techniques to treat perchlorate impacted groundwater, this time using no-cost effluent from Hodgdon’s on-site wastewater biological treatment plant. Pilot test efforts successfully resulted in significant perchlorate degradation and Blackstone extended this in-situ remedial approach to treat the entire groundwater source area.
Source-area groundwater treatment and off-site groundwater monitoring are ongoing.