Longhorn Army Ammunition Plant

Environmental Restoration Program

LHAAP-04

Site Description/History

LHAAP-04, also known as the Former Pilot Wastewater Treatment Plant, is located in the central portion of LHAAP at the northwest corner of 6th and 60th Streets near the former fire station and covers approximately 0.5 acre. LHAAP-04 began industrial wastewater treatment operations in 1984 and historical operations resulted in environmental impacts to soil and groundwater. Demolition of the Former Pilot Wastewater Treatment Facility structures, tanks, and piping, and the disposal of associated wastes were completed in the summer of 1997 as part of Resource Conservation and Recovery Act closure of the plant.

Remediation Activities

Numerous sampling events were conducted from 1993 through 2008 to identify contamination from past operations and its impact to soil. In coordination with the U.S. Environmental Protection Agency (USEPA) and the Texas Commission on Environmental Qualtiy (TCEQ), Army implemented a non-time-critical removal action in 2009 through which a total of approximately 3,406 cubic yards of soil contaminated with perchlorate and mercury were excavated and transported off site, eliminating the principle threat at the site.

Contaminants of Concern

Perchlorate in groundwater

Current Phase

Final Record of Decision (ROD) was signed by EPA March 30, 2017. The selected remedy includes in-situ bioremediation (ISB) to reduce contaminant of concern concentrations in groundwater to meet the cleanup level, Long-Term Monitoring (LTM) of groundwater, and land use controls (LUCs).

Future Phase

Future planned phases to complete remedy implementation are Remedial Design (RD) and Remedial Action Construction (RAC).