Featured Project: 1 Million Gallon Contaminated Water Treatment – Gulf Coast Pygas Tank (TCEQ & Title V Compliance)
A Gulf Coast refinery needed to empty a 132 ft diameter × 56 ft tall internal floating-roof tank previously in pyrolysis gasoline (Pygas) service and recently used for waste/contaminated water storage before API 653 inspection. The water was heavily loaded with oil, grease, and suspended solids — far exceeding the facility’s downstream treatment capabilities and risking TCEQ Title V deviations or RCRA violations if discharged untreated.
Off-site deep-welling or trucking would have cost $500K+ and delayed inspection by weeks.
The Challenge
- ~1,000,000 gallons of mixed oily/contaminated water
- High oil & grease, TSS, and benzene (Pygas residuals)
- Must meet TCEQ Industrial Wastewater Discharge and 40 CFR Part 261 (RCRA) standards before downstream processing
- No downtime allowed – inspection clock was running
Envent’s Mobile 88 GPM Solution – Cavitated Air Flotation (CAF)
Envent performed a full bench-scale treatability study, selected the optimal coagulant, and deployed a complete temporary treatment train:
| Process Step | Equipment & Media |
|---|---|
| Coagulant Injection | Custom polymer selected via bench testing |
| Cavitated Air Flotation (CAF) Unit | 88 GPM – micro-bubble flotation for oil/TSS removal |
| Vapor Control | Full EMTOS thermal oxidizer on CAF off-gas |
| Solids/Waste Storage | Frac tanks for oil skim & sludge |
| Final Polishing & Sampling | Holding tank + lab verification before discharge |
Performance
- Processed 1,000,000 gallons in under 6 days (vs. 8-day estimate)
- Effluent: – Oil & Grease: <5 mg/L – TSS: <10 mg/L – Benzene: non-detect
- 100% compliant with TCEQ and facility downstream limits
Proven Results – 6 Days, Zero Issues, Major Savings
| Benefit | Delivered Outcome |
|---|---|
| Speed | <6 days vs. 8-day estimate |
| Cost Savings | Hundreds of thousands vs. deep-welling/trucking |
| Compliance | 100% met TCEQ wastewater & RCRA standards |
| Inspection Schedule | Tank handed over on time for API 653 inspection |
| Safety & Environmental | Zero spills, zero odors, zero vapor release |
This project is why Gulf Coast refineries now use Envent’s mobile water treatment trailers for tank bottoms, slop oil, and stormwater jobs.
Got oily or contaminated water blocking your tank inspection or turnaround? Get your Free Treatability Study & Mobile Water Treatment Quote today. Call Envent’s Water Team at 888-997-9465 or email [email protected] — we turn dirty water into discharge-ready in days.
