The site is an active firing range in Cedar Rapids, IA for police officer training. The backstop berm area was reconstructed to address environmental concerns with high-lead concentrations in the soil and to provide additional protection for neighboring properties.
The remedial objectives at this site were to stabilize the lead-impacted soil to meet the Toxicity Characteristic Leaching Procedure (TCLP) criteria for lead, recycle lead bullets, and restore the berm for future use.
Prior to screening lead from the berm soil at the gun range, the soil was stabilized using EnviroBlend®, a dry, coarse chemical delivered to the site in dump trucks. EnviroBlend was applied superficially to site areas requiring treatment, then mechanically blended into the soil using a tracked excavator. The soil was blended until a homogenous mixture was achieved. In-situ treatment of the soil prior to excavation allowed the material to be rendered non-hazardous prior to further management, avoiding generation of an unpermitted hazardous waste pile. Following treatment of the soil, two samples were collected for Toxicity Characteristic Leaching Procedure (TCLP) – lead analysis. The TCLP results demonstrated lead concentrations below 5 mg/L in the stabilized material.
After the soil was treated and confirmed to be non-hazardous, the contractor screened lead bullets from the soil using a MKII PowerScreen with a 3-inch upper deck and a ¼ -inch lower deck. Soil was fed into the hopper on the screen, and three material piles were generated:
- Material retained on the 3-inch screen – typically large soil clods, debris, and rocks
- Material retained on the ¼ -inch screen – expected to be lead material
- Material passing through both screens – fine soil particles
Lead recovered from the soil was to be transported to the Doe Run Resource Recovery Facility in Boss, MO for recycling. Analysis of the lead-containing material screened from the soil indicated it was approximately 50% lead by weight and not suitable for recycling. EnviroBlend stabilizes soil, and the treated material is stable over a wide range of conditions and is protective of leaching to groundwater. Because of this quality, the screened and stabilized material could be used as a backfill for reconstructing the core of the backstop berm.
The total project cost for EnviroBlend stabilization and screening was $45,000 which provided significant savings over hazardous waste disposal.