Petroleum Hydrocarbon Treatment
Proven strategies for treating BTEX, TPH, PAHs, and fuel hydrocarbons using bioremediation, chemical oxidation, and advanced combined technologies
Treatment Technologies
Target Compounds
Mechanisms
- Persulfate radical (SO₄•⁻) oxidation: 2.60V potential
- Ferrate (Fe(VI)) oxidation: 2.20V potential
- Direct persulfate oxidation: 2.01V potential
- Secondary bioremediation via sulfate/iron as electron acceptors
- Prevents rebound through sustained biological treatment
Advantages
- Rapid initial oxidation followed by biological polishing
- Effective on both aromatic and aliphatic hydrocarbons
- Works in all soil types including low permeability
- No rebound - combined oxidative/reductive mechanisms
- Treats dissolved and LNAPL/DNAPL phases
- Single component system
Limitations
- Higher cost than bioremediation alone
- Initial turbidity from iron precipitation
- Requires dosing optimization
Target Compounds
Mechanisms
- Aerobic bacterial oxidation: petroleum + O₂ → CO₂ + H₂O
- BTEX degradation order: Toluene > Ethylbenzene > Xylenes > Benzene
- Oxygen delivery via metallic peroxides (Ca, Mg)
- Nutrient addition (N, P) optimizes bacterial growth
- Biosurfactants enhance bioavailability
Advantages
- Cost-effective for large plumes
- Complete mineralization to CO₂ and water
- Natural attenuation enhancement
- Low site disruption
- Proven long-term performance
- Effective for moderate concentrations
Limitations
- Requires favorable geochemistry
- Slower than oxidation
- Benzene degrades slowest in BTEX suite
- Trimethylbenzenes can be recalcitrant
- May produce VFAs under nutrient-limited conditions
Target Compounds
Mechanisms
- Anaerobic degradation: petroleum + SO₄²⁻/Fe³⁺/NO₃⁻ → CO₂ + reduced products
- Electron donor (emulsified oil, molasses) creates reducing conditions
- Sulfate reduction, iron reduction, or methanogenesis
- BTEX can degrade anaerobically with proper electron acceptors
Advantages
- Effective for high-concentration LNAPL
- Long-lasting treatment zones
- Lower oxygen demand than aerobic
- Can treat recalcitrant compounds like MTBE
- Complements aerobic zones
Limitations
- Slower kinetics than aerobic
- Methane generation risk
- Requires careful geochemical management
- Sulfate or other electron acceptors needed
- Not suitable for all petroleum fractions
Target Compounds
Mechanisms
- ZVI catalyzes H₂O₂ → hydroxyl radicals (OH•): 2.80V
- Ferrous iron activates persulfate → sulfate radicals: 2.60V
- Residual ZVI provides long-term hydrogen and electrons
- Sequential oxidation then reduction
- Supports anaerobic biological processes after oxidant depletion
Advantages
- Most powerful oxidation system
- Treats petroleum + chlorinated co-contaminants
- Long-term treatment from residual ZVI
- Prevents rebound through multiple mechanisms
- Effective on recalcitrant PAHs and heavy oils
Limitations
- Complex chemistry requires expertise
- Higher material costs
- Carbonate buffering can reduce efficiency
- Requires careful ratio optimization
Contaminant-Specific Guidance
Compounds:
Degradation Order:
Toluene > Ethylbenzene > p-Xylene > m-Xylene > Benzene > o-Xylene
Preferred Technology:
Aerobic Bioremediation or Ferric Persulfate
Notes:
Benzene is slowest to degrade aerobically. Toluene degrades fastest. Persulfate provides rapid initial removal with bioremediation for polishing.
Compounds:
Degradation Order:
Light ends (C6-C12) > Mid-weight (C12-C24) > Heavy ends (C24-C40)
Preferred Technology:
Enhanced Bioremediation (aerobic for light, anaerobic for heavy)
Notes:
Light petroleum fractions degrade readily aerobically. Heavy fractions and LNAPL may require anaerobic or oxidative approaches.
Compounds:
Degradation Order:
2-ring > 3-ring > 4-ring > 5-6 ring
Preferred Technology:
Chemical Oxidation (Persulfate or Permanganate)
Notes:
Low solubility and high sorption make PAHs challenging. Oxidation is most effective. High molecular weight PAHs (4+ rings) very recalcitrant.
Compounds:
Degradation Order:
Ethanol > TAME > TBA > MTBE
Preferred Technology:
Anaerobic Bioremediation or Persulfate Oxidation
Notes:
MTBE is highly recalcitrant aerobically but degrades anaerobically with proper electron donors. Persulfate provides rapid oxidation.
Design Framework
- Define contaminant distribution (dissolved, LNAPL, sorbed)
- Characterize soil lithology and hydraulic conductivity
- Evaluate geochemistry: pH, ORP, DO, sulfate, nitrate, TOC
- Assess natural attenuation capacity
- Identify sensitive receptors and regulatory requirements
- BTEX dominant, aerobic aquifer → Enhanced Aerobic Bioremediation
- High concentrations, LNAPL present → Ferric Persulfate or Anaerobic Bio
- Low permeability → Persulfate Oxidation
- PAH contamination → Persulfate or Permanganate
- Mixed petroleum + chlorinated → ZVI-Peroxide-Persulfate
- Test multiple technologies in representative zones
- Optimize amendment dosing and delivery methods
- Monitor for target contaminants and intermediates
- Evaluate geochemical changes and biological response
- Refine design based on pilot results
- Install injection points (direct push or wells)
- Deploy amendments via gravity feed or pressurized injection
- Establish performance monitoring network
- Track contaminant concentrations, geochemistry, biological indicators
- Adjust approach based on performance data
Case Study Highlights
Former Gas Station - Northeast
Industrial Facility - Midwest
Bulk Fuel Terminal - South
Former MGP Site - Mid-Atlantic
Petroleum Hydrocarbon Remediation — Frequently Asked Questions
Answers to common questions about IET's petroleum remediation technologies and experience.
What petroleum contaminants does IET treat?
IET treats BTEX, total petroleum hydrocarbons (TPH), gasoline, diesel, light fuel oils, PAHs, naphthalene, MTBE, and LNAPL/DNAPL source zones using activated persulfate, enhanced aerobic bioremediation, catalyzed hydrogen peroxide, and ISCR.
What is the best technology for petroleum remediation?
For most petroleum sites, IET's ferric iron-activated persulfate provides rapid oxidation followed by sustained biological polishing that prevents rebound. Enhanced aerobic bioremediation is cost-effective for large dilute plumes. IET selects the technology based on contaminant, soil type, and cleanup goals.
How long does petroleum remediation take?
Activated persulfate ISCO shows significant reduction in 6–18 months with sustained treatment preventing rebound. Enhanced aerobic bioremediation typically requires 9–24 months for complete mineralization to CO₂ and water.
Can IET treat LNAPL source zones?
Yes. IET treats LNAPL and dissolved-phase petroleum using combined oxidative and reductive mechanisms, with single-component systems effective across all soil types including low-permeability formations.
How many petroleum sites has IET remediated?
IET has successfully treated 400+ petroleum hydrocarbon sites nationwide, applying proven ISCO and bioremediation technologies since 1998.