Featured Project: 5 Million Gallon VOC & Benzene Water Treatment – West Texas Terminal (NPDES Storm Sewer Discharge)
A major West Texas crude terminal accumulated 5 million gallons of contaminated stormwater and process water loaded with VOC, benzene, oil & grease, and particulates in frac tanks and containment after heavy rains and tank cleaning operations.
The terminal needed to discharge to the municipal storm sewer system under a new individual NPDES permit — but had no on-site treatment capability. Off-site disposal would have cost $750K+ and taken months.
Envent secured the permit and treated everything on site in 21 days.
The Challenge
- 5,000,000 gallons in multiple frac tanks
- High benzene, VOCs, oil & grease, TSS
- Must meet NPDES individual permit limits for storm sewer discharge: – Benzene < 0.005 mg/L – Total BTEX < 0.1 mg/L – Oil & Grease < 10 mg/L – TSS < 30 mg/L
- Zero tolerance for spills or odors near community
- Tight schedule before next rain event
Envent’s Turnkey Mobile Water Treatment Solution
Envent engineers wrote and secured the individual NPDES permit with TCEQ/EPA in record time, then deployed:
| Process Step | Equipment & Media |
|---|---|
| Temporary 6″ Pipeline | 1,200+ ft HDPE from tanks to treatment area |
| Oil/Water Separation & TSS | 88 GPM Cavitated Air Flotation (CAF) + coagulant |
| VOC & Benzene Polishing | Dual 20,000-lb GAC vessels in lead-lag |
| Final Verification | Composite sampling + on-site lab |
| Discharge | Direct to storm sewer with flow meter & auto-sampling |
Performance
- Treated >240,000 gallons per day
- Effluent results: – Benzene non-detect (<0.001 mg/L) – Oil & Grease <5 mg/L – TSS <15 mg/L
- 100% compliant with all NPDES limits
Proven Results – $750K+ Saved, Zero Issues
| Benefit | Delivered Outcome |
|---|---|
| Cost Savings | >$750,000 vs. off-site disposal |
| Speed | 5M gallons in 21 days |
| Compliance | 100% NPDES & TCEQ individual permit |
| Schedule | Finished before next rain — tanks ready for service |
| Safety & Community | Zero spills, zero odors, zero complaints |
This project is why West Texas terminals now call Envent first for stormwater, tank-bottom, or produced-water treatment.
Got contaminated stormwater or process water blocking your terminal? Get your Free NPDES Discharge Permit Review & Mobile Treatment Quote today. Call Envent’s Water Team at 888-997-9465 or email [email protected] — we get you back in service fast and clean.
