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.

Treatment Guide

Petroleum Hydrocarbon Treatment

Proven strategies for treating BTEX, TPH, PAHs, and fuel hydrocarbons using bioremediation, chemical oxidation, and advanced combined technologies

Treatment Technologies

Excellent

6-18 months

Ferric Iron-Activated Persulfate

Target Compounds

BTEX

TPH

PAHs

Alkylbenzenes

Naphthalene

MTBE

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

Excellent

9-24 months

Enhanced Aerobic Bioremediation

Target Compounds

BTEX

Diesel

Gasoline

Light Fuel Oils

TPH

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

Good to Excellent

12-36 months

Enhanced Anaerobic Bioremediation

Target Compounds

BTEX (under sulfate/iron conditions)

MTBE

Naphthalene

Diesel

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

Excellent

6-24 months

ZVI-Peroxide-Persulfate Combined

Target Compounds

Recalcitrant TPH

PAHs

BTEX

Co-contaminants

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

BTEX Compounds

Compounds:

Benzene

Toluene

Ethylbenzene

Xylenes

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.

Total Petroleum Hydrocarbons (TPH)

Compounds:

Gasoline

Diesel

Jet Fuel

Heating Oil

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.

Polycyclic Aromatic Hydrocarbons (PAHs)

Compounds:

Naphthalene

Anthracene

Pyrene

Benzo(a)pyrene

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.

Fuel Oxygenates

Compounds:

MTBE

TBA

TAME

Ethanol

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

Site Assessment

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

Technology Selection

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

Pilot Testing

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

Full-Scale Implementation

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

Contaminants: BTEX, TPH-GRO

Technology: Enhanced Aerobic Bioremediation

Result: 95% BTEX reduction in 14 months, closure achieved

Industrial Facility - Midwest

Contaminants: Diesel, Heavy TPH

Technology: Ferric Iron-Activated Persulfate

Result: 88% TPH reduction in 9 months, no rebound observed

Bulk Fuel Terminal - South

Contaminants: Gasoline LNAPL, BTEX

Technology: Enhanced Anaerobic Bioremediation

Result: LNAPL depleted in 18 months, dissolved plume stabilized

Former MGP Site - Mid-Atlantic

Contaminants: PAHs, BTEX, Naphthalene

Technology: ZVI-Peroxide-Persulfate

Result: 92% PAH reduction, 97% BTEX reduction in 12 months

Ready to Discuss Your Petroleum Remediation Project?

Our team has successfully treated 400+ petroleum hydrocarbon sites. Let us help you select the optimal technology for your site conditions.

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.