Bioaugmentation to Improve Oxygen Delivery Results

Many times oxygen is injected to improve natural attenuation of petroleum and other contaminants.  The results are often less than expected because the beneficial microbes that the oxygen addition is supposed to stimulate are absent or insufficient in numbers.  Bioaugmentation has been used to improve the results once the oxygen levels have increased but failed to improve the remediation rate.

The following table shows the results of Petrox bioaugmentation at a site in New Hampshire where the operation of an iSOC oxygen-delivery system failed to achieve stimulated bioremediation.  The table shows the improvement of the degradation rates and the achievement of reaching remediation goals.

Contaminant Pre-iSOC After iSOC Installation After Petrox Application
3/19/2002 1/9/2003 11/29/2004 2/9/2005 4/22/2005
Benzene 33 34 163 27 <2
Toluene 36 13 143 13 <2
Ethylbenzene 130 29 167 29 <2
Total Xylenes 500 141 336 109 <2
MTBE 60 24 61 35 1
Naphthalene 320 196 58 17 <2
1,2,4-Trimethylbenzene 110 40 238 110 <2
1,3,5-Trimethylbenzene 54 29 25 16 <2

California Site Closure with Petrox Bioremediation

Southern California Gasoline UST Release Site

After removal of USTs, piping and surrounding soils, ground water was treated with 110 gallons of Petrox® by direct injection in December 2009.  Post-treatment sampling shows that the bioaugmentation reduced the contaminant levels to below regulatory standards by the next semi-annual sampling round.

Sampling Date

TPHg Benzene Toluene Ethylbenzene

Total   Xylenes



1,200 320 7.2 700




<50 <0.5 <0.51 <1



All concentrations shown in µg/L.

Florida Site Closures With One Petrox Application

The following applications demonstrate the significant results that can be achieved with a single application of Petrox bioremediation.

Florida Panhandle Gas Station

Facility ID # 32-8520334

Petrox was injected through horizontal drilling to address a ground water plume with limited surface access.  After a single Petrox® application there was significant reduction in the contaminant concentrations.

Sampling Date Benzene Toluene Ethyl benzene Xylene Naph-thalene 2-Methyl naphthalene
Pre- bioaugmentation 11/11/05 4,300 3,000 1,300 5,300 240 48
10/23/07 2,700 4,200 860 5,700 240 41
Post-bioaugmentation 11/06/08 1.7 8.5 0.71 5.1 0.49 0.45
1/22/09 0.88 0.64 0.43 1.3 0.49 0.45

All Concentrations shown in µg/L.


Southeast Florida Gas Station

Facility ID 8838788

After removal of USTs, piping and surrounding soils Ground water was treated with 110 gallons of Petrox® by direct injection in June 2009.  Sampling six months after the Petrox® treatment showed significant reductions in all contaminants.

Sampling Date Benzene Toluene Ethylbenzene Total Xylenes
Pre-  bioaugmentation 4/4/2008 480 1800.0 110.0 900.0
Post- bioaugmentation 11/12/09 <0.5 <0.51 <0.44 <0.5

All concentrations shown in µg/L.


Southeastern Florida Marina

Tequesta, Florida

Facility ID # 43-8731703

Subsequent to the removal of petroleum underground storage tanks (USTs), piping and surrounding soils for redevelopment, residual soil and ground water contamination at the site were treated with Petrox® bioremediation.  Petrox® was applied to the soil that was removed during the UST removals and to the ground water in the UST cavity.

Approximately 4,000 tons of soil were removed from the excavation and stockpiled on site for treatment.  The total BTEX concentrations in the excavated soil were up to 100 mg/kg.  Petrox® bioremediation was applied to the stockpiled soils.  In less than 90 days the petroleum was no longer detected in the soil and in the soil met the applicable Florida DEP standards.

Petrox® bioremediation was applied to the water in the former UST cavity to treat residual petroleum.  The proximity of the cavity to the Jupiter Sound indicated that the ground water was strongly influenced by infiltration from the Sound.  After less than 90 days post treatment, the water in the excavation also met the applicable Florida DEP standards.


Maximum Water Conc. Benzene Toluene Ethylbenzene Total Xylenes
Pre-treatment 1,960 5,140 1,860 18,340
90 days after treatment 3.7 BDL BDL BDL

All concentrations shown in µg/L. BDL= below detection limits.


Central Florida Gas Station

Petrox was applied to the ground water in an area around a single monitoring well that did not respond to another treatment as well as the rest of the plume.  A single 10-gallon application of Petrox® was sufficient to apply for site closure.

Sampling Date Benzene Toluene Ethylbenzene Total Xylenes
Pre- treatment 8/2/2007 11,100 1,250 1,260 5,040
Post-treatment 10/4/07 1,600 20.0 290. 840.
11/19/07 0.40 1.0 1.00 32.0

All concentrations shown in µg/L.


Fast BTEX Bioremediation

Petrox bioaugmentation achieves fast BTEX bioremediation at the point of injection.  In most cases, the monitoring points are distant from the injection points. The speed of remediation depends on the rate of microbial dispersion from the injection point.

The following chart shows the speed of  bioremediation at two monitoring points. Three months after the initial bioaugmentation, the total BTEX concentration decreased more than 99% in one well and 77% in the other well.   Two months after the second bioaugmentation, the concentration in both monitoring wells was below detection limits.

fast BTEX bioremediation

Easy Bioremediation of Oil Surface Spills

Petrox  bioremediation of oil surface spills reduces TPH accumulation in drainage ditches and maintenance areas. Using a simple manual sprayer, Petrox microbes applied to the soil surface begin bioremediation immediately.

The following chart shows the results of the application of 10 gallons of Petrox to petroleum-contaminanted soil in a drainage ditch. After about 60 days, the TPH concentration was reduced by 67% in one location and over 90% in three locations. The Petrox cost to treat 2,000 square feet was $200.

Shallow Soil Treatment Results