Cover Slide TCEQ logo

Cost Effective Strategies for Groundwater Remediation Midori Campbell, P.E.

Water Use by Industry in Texas, 2013 2% Livestock 58% Irrigation 30% Municipal 6% Manufacturing 1% Mining 3% Power 53 % Groundwater 47 % Surface Water 37 % Groundwater 63 % Surface Water 84 % Groundwater 16 % Surface Water 23 % Groundwater 77 % Surface Water 77 % Groundwater 23 % Surface Water 10 % Groundwater 90 % Surface Water

Groundwater Protection Statutes Federal: Safe Drinking Water Act (SDWA) Resource Conservation and Recovery Act (RCRA) Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Texas: Texas Water Code

Sites Beneath Which There is Groundwater Contamination in Ector County, Texas This is a map from 2012. Groundwater beneath these sites are contaminated with hexavalent chromium and volatile organic compounds. Although the contamination appears to be wide-spread, each site is unique. Ector County, Texas

Groundwater Remediation Strategy Factors Containment Versus Aquifer Restoration Exit Strategy Performance-Based Monitoring Capital Costs and Annual Operation and Maintenance (O&M) Costs

Containment Versus Aquifer Restoration Containment: Prevents a contaminant from reaching an identified receptor(s) above a protective level. Aquifer Restoration: Reduce the contaminant’s mass in the aquifer to achieve the established protective level.

Exit Strategy What are the milestones for measuring progress? How is the progress monitored? What resulting action is associated with achieving these milestones? What is the contingency plan if one or more milestones are not achieved?

Performance Based Monitoring Incorporate with the exit strategy into the remedial design. Select indicator parameters where possible. Incorporate with the exit strategy into the remedial design. Select indicator parameters where possible. Minimize sampling near source. Use remote monitoring (e.g., using telemetry) when feasible. Performance-Based Monitoring Use remote monitoring (e.g., using telemetry) when feasible. Minimize sampling near source.

Strategy for Containment Realize that a complete exit strategy for containment may not exist. Performance monitoring may demonstrate that hydraulic control is maintained or degradation or attenuation of contaminants over time is achieved. Exit strategies of components may be possible (e.g., increase pumping and reduce or eliminate sampling.)

Image of Geneva Industries Federal Superfund Site in Houston, Texas This aerial image of the Geneva Federal Superfund site shows the site boundaries, the locations of the monitoring and recovery wells, slurry wall, and groundwater treatment facility.

Strategy for Aquifer Restoration If source areas exist, consider treating areas downgradient separate from source areas. Prevents downgradient migration of source area contaminants, including non-aqueous phase liquids (NAPLs) Allows for cleanup goals to be achieved earlier in downgradient areas. Reduces monitoring requirements. New, proven technologies can be applied as they develop.

Capital and O&M Cost Considerations Infrastructure Life Cycle Automation Disposition of Treated Groundwater

Infrastructure Can an existing infrastructure be utilized? Is the site-wide contamination uniform to allow a large scale infrastructure? Would a network of smaller components allow more opportunities for reducing overall O&M?

Sprague Road Federal Superfund Site in Odessa, Texas Machine and Casting The Sprague Road Federal Superfund site encompasses three sites overlying three separate groundwater plumes. Machine and Casting overlies the northernmost plume, Leigh Metals overlies the central plume, and National Chromium overlies the southernmost plume. Sprague Road Federal Superfund Site Odessa, Texas Leigh Metals National Chromium

PhotoCat Groundwater Treatment System The PhotoCat groundwater treatment system at Sprague Road is situated inside a building at Leigh Metals.

Potential Locations for In-situ Treatment at Leigh Metals and National Chromium Three in-situ treatment zones are recommended each at Leigh Metals and National Chromium

Time to Achieve Remedial Action Objectives (RAOs) Life Cycle Time to Achieve Remedial Action Objectives Short Term Consider leasing equipment. Being aggressive initially may shorten the life cycle. Long Term Consider areas where RAOs can be achieved short-term and other areas where system may be operating until perpetuity. Perpetuity Re-evaluate RAOs, conduct optimization review. Automate as much of the remediation efforts as possible. Consider leasing equipment. Being aggressive initially may shorten the life cycle. Short Term Time to Achieve Remedial Action Objectives (RAOs) Consider areas where RAOs can be achieved short-term and other areas where system may be operating until perpetuity. Long Term Perpetuity Re-evaluate RAOs, conduct optimization review. Automate as much of the remediation efforts as possible.

Automation Minimizes time lost to shut-downs. Safety net to prevent contaminants from being discharged or migrating off-site unknowingly. Allows for remote troubleshooting and monitoring. Initial costs are offset by savings in labor.

Disposition of Treated Groundwater for Above-Ground Systems Re-injection of treated groundwater for recharge, hydraulic control, and/or vadose zone flushing Infiltration gallery Infiltration basin Injection wells NPDES or POTW discharge Re-use

First Quality Cylinders State Superfund Site in San Antonio, Texas This site map shows the locations of the site boundary, monitoring wells, boundary of the plume management zone, the existing trench, the slurry wall, and the groundwater treatment system, which is not currently in use.

Removal Action This photograph shows the initial removal action inside a building at First Quality Cylinders.

Secured Excavation Soil excavated to 12 feet below ground surface (bgs) and backfilled Bottom 5 feet was select fill amended with 1 gallon calcium polysulfide solution per 1 cubic yard of soil. Remainder of the excavation, up to 12 inches bgs, was backfilled with select fill. The top was finished with compacted flex base limestone to grade.

In-Situ Chemical Reduction at First Quality Cylinders A 29% CPS solution was injected in temporary vertical-bush borings Borings were each 1.5 inches in diameter Target interval was from 7 to 12 feet bgs Each injection was followed by 160 gallons of clean chase water.

Discharge Criteria Met at First Quality Cylinders State Superfund Site

Groundwater Remediation is a Dynamic Process Changing Regulatory Environment Emerging Contaminants Emerging Technologies Changing Site Characteristics Develop a sound strategy!

Questions?