Featured Project: Permanent Fugitive Emissions Elimination on Aging DAF Cell Lids – Automated Thermal Oxidizer & LDAR Compliance
With LDAR enforcement intensifying nationwide (e.g., SCAQMD Rule 1173, BAAQMD Reg 8-18, TCEQ HRVOC, Colorado Reg 7), even low-pressure sources like Dissolved Air Flotation (DAF) cell lids on oil-water separators are now monitored via Method 21 and optical gas imaging. Aged fiberglass or steel lids routinely leak 500–5,000 ppmv VOCs, triggering mandatory repairs, root-cause analysis, and potential $25,000+/day fines.
This facility chose to get ahead of regulators with a permanent, automated vapor control system instead of endless repairs.
The Challenge: Fugitive VOCs from Old DAF Cell Lids
- Aging lids on multiple DAF cells leaking detectable hydrocarbons
- Method 21 readings routinely >500 ppmv (some >10,000 ppmv)
- Risk of major LDAR violations and consent decree exposure
- Manual venting or carbon cans were temporary and ineffective
Envent’s Permanent Solution: Custom Automated Thermal Oxidizer System
Envent designed, fabricated, and installed a fully automated, plant-integrated thermal oxidizer system that maintains a slight negative pressure inside every DAF cell — ensuring zero fugitive emissions at the lid seals.
Key System Features
- Selective Vacuum Control: Motorized dampers automatically cycle between cells to maintain −0.1 to −0.5 in. w.c. on each lid
- Dedicated Thermal Oxidizer: 500–1,000 scfm enclosed unit with >99.9% DRE at 1,600 °F
- Plant Utility Integration: Uses site natural gas and electricity — no diesel generator or supplemental fuel fuel costs
- Full Automation: PLC + HMI with remote monitoring — runs 24/7 without operator attendance
- Safety: Flame arrestors, LEL monitoring, auto-shutdown, and explosion vents
Post-installation Method 21 surveys: 0 ppmv detectable on every lid.
Proven Benefits – Permanent LDAR Compliance
| Benefit | Delivered Outcome |
|---|---|
| Fugitive Emissions | 100% eliminated — zero leaks above 500 ppmv |
| LDAR Compliance | Removed DAF cells from future Method 21 monitoring |
| Regulatory Satisfaction | Passed air district inspection with flying colors |
| Operating Cost | Uses plant utilities — no generator/fuel expense |
| Labor Savings | Fully automated — no daily operator required |
| Longevity | Permanent stainless steel system built for 20+ years |
This system has become the gold standard for oil recovery units, API separators, and wastewater tanks in strict LDAR jurisdictions.
