Remedial Design/Engineering

Cornhusker Army Ammunition Plant, NE

$6.6M, 2006-09

Bay West completed a 3-yr performance-based contract involving O&M of a 750-gpm groundwater extraction (hydraulic containment) and treatment system for explosives and low-level VOC-impacted groundwater.

In addition, Bay West designed and implemented a biostimulation amendment injection program for promoting in situ anaerobic biological degradation of the VOC and explosives plume. Groundwater extraction provides hydraulic control of the plume and provides a mechanism that promotes amendment dissolution and distribution into the aquifer.

Bay West was responsible for operating and maintaining the groundwater recovery and treatment system including the backwashing of the two 20,000-lb granular-activated carbon (GAC) treatment vessels. Bay West’s plant operator controlled the extraction well pumps using radio frequency communications between the treatment plant control room and the local controls in each pump house. Using this technology, the extraction well performance was continuously monitored and adjusted from the control room.

Bay West performed all treatment system sampling activities to provide the required analyses to ensure system performance was in conformance with the Record of Decision. Bay West also performed LTM including annual sampling of approximately 130 monitoring wells. Bay West’s plant operator performed inspections of the discharge canal and performs periodic canal maintenance, including maintenance of mini-weirs and vegetation removal.

Bay West achieved a greater than 25% reduction in explosives mass in the treatment zone within 1 year of each of the three injection events and has been retained under a separate competed task order to continue RAO, LTM, and O&M activities for two additional years.

Our successful project execution resulted in the following comment from the US Army Corps of Engineers Project Manager: “Bay West has utilized all of its capabilities (partnered subcontract) and local business participants to execute the work to the satisfaction of the Army PDT. The contractor has provided timely submittals and excellent documents for regulatory review and archive records. Site operating problems are minimal and easily resolved to the satisfactions of all stakeholders.”