We deploy a dual-phase extraction rig with a 300-gpm vacuum system for contaminated soil remediation in Houston, a city where the Gulf Coast alluvial plain meets industrial petrochemical legacy. The rig combines a 40-ft auger for soil blending with an activated carbon filtration unit, allowing us to treat volatile organic compounds on-site without hauling. This setup reaches depths of up to 25 feet, typical for Houston's soft clays and silty sands that often host chlorinated solvents from decades of refinery operations. Before mobilizing, we run a site characterization that includes a resistivity survey to map contaminant plumes in the shallow aquifer, ensuring the extraction wells target the saturated zone precisely.
In Houston's clay-rich soils, in-situ chemical oxidation achieves 95% BTEX removal within 14 days, provided injection spacing is calibrated to the 10⁻⁶ cm/s permeability.
Methodology and scope
We follow ASTM E1527-21 Phase I ESA protocols and the Texas Commission on Environmental Quality (TCEQ) Risk Reduction Rules (30 TAC Chapter 350) for all remediation work in Houston. The local soil profile — Beaumont clay interbedded with sands from the Brazos River alluvium — demands a tailored approach. We apply in-situ chemical oxidation using sodium persulfate activated with ferrous iron, which degrades BTEX compounds within a 15-foot radius per injection point. For heavy metals like arsenic and lead, we use phosphate-induced metal stabilization. Each batch of treated soil passes the TCLP (Toxicity Characteristic Leaching Procedure, EPA Method 1311) before backfill. We also deploy soil vapor extraction on sites with shallow groundwater (2-4 ft below grade), which is common west of Downtown Houston. The entire process is documented in a Remedial Action Plan (RAP) submitted to the TCEQ.
Technical reference image — Houston
Local considerations
A 15-story office tower on Buffalo Bayou's south bank hit a buried dry-cleaning solvent plume during foundation excavation for a mat foundation. The initial 6-ft deep excavation revealed trichloroethene (TCE) at 12 mg/kg, ten times the TCEQ Residential SSL. We halted all soil hauling and switched to on-site thermal desorption using an indirect-fired rotary kiln operating at 400°C. The operation treated 1,200 cubic yards of contaminated soil over 18 days, with vapor capture through a carbon bed. The project schedule slipped 6 weeks but avoided $500k in off-site disposal fees. The lesson: early vapor intrusion screening with a georadar survey can spot buried tanks or drywells before excavation, cutting the risk of finding contamination mid-construction.
BTEX, PAHs, chlorinated solvents, heavy metals (Pb, As, Cr)
Injection Grid Spacing (ISCO)
10 ft x 10 ft (sandy zones) / 15 ft x 15 ft (clay)
Soil Vapor Extraction Flow Rate
150 – 300 scfm per well
Treated Soil Confirmation
TCLP (EPA 1311) + Total Petroleum Hydrocarbons (EPA 8015)
Mobilization Time
7-10 business days within Harris County
Associated technical services
01
In-Situ Chemical Oxidation (ISCO)
We inject sodium persulfate and ferrous iron catalyst through a grid of 2-inch PVC wells spaced 10 to 15 feet apart, depending on soil permeability. The reaction breaks down BTEX and chlorinated solvents within 14 days, with oxidation front radius verified by ORP monitoring. We treat volumes from 500 to 10,000 cubic yards per project, with no soil removal required.
02
Soil Vapor Extraction (SVE)
For volatile compounds in the vadose zone, we install 4-inch slotted PVC wells connected to a 300-cfm vacuum blower. The extracted vapor passes through an activated carbon drum rated for 500 ppmV inlet concentration. We monitor effluent with a PID every 4 hours to confirm breakthrough limits. Typical cleanup time is 30-60 days for a 0.5-acre footprint.
How do you determine if a site in Houston needs remediation?
We start with a Phase I ESA (ASTM E1527-21) to identify recognized environmental conditions. If a release is suspected, we collect soil samples at 5-ft intervals using a Geoprobe 6620DT. Samples are analyzed for BTEX, PAHs, metals, and chlorinated VOCs. Results are compared to TCEQ Protective Concentration Levels (PCLs) from 30 TAC Chapter 350. Exceedances trigger a Remedial Action Plan.
What is the typical timeline for contaminated soil remediation in Houston?
For a 1,000-cubic-yard site with BTEX contamination, in-situ chemical oxidation takes 14-21 days for injection and 30 days for post-treatment verification. Soil vapor extraction spans 45-60 days with continuous monitoring. Thermal desorption of 1,200 cubic yards runs 18-22 days. Off-site disposal is fastest (5-7 days) but carries the highest total cost.
How much does contaminated soil remediation cost in Houston?
For a typical 500-cubic-yard site with moderate hydrocarbon contamination, costs range between US$3,550 and US$14,310 depending on treatment method, depth, and accessibility. In-situ chemical oxidation is at the lower end; thermal desorption or off-site disposal pushes costs higher. A detailed cost estimate requires a site-specific characterization.
Do you handle TCEQ reporting for contaminated sites?
Yes. We prepare and submit all required documentation to the TCEQ Remediation Division, including the Phase I ESA, Remedial Action Plan (RAP), and closure reports. Our reports follow the TCEQ format and include chain-of-custody forms, laboratory analytical data, and a summary of treated soil confirmation results.
Location and service area
We serve projects across Houston and its metropolitan area.
