Improving Long-Term Bioremediation Results with Nutrients

The goal of bioaugmentation is to improve the rate of contaminant removal by adding a high population of beneficial microbes to the contaminated media.  The additional microbes  should provide short-term benefit as the microbes begin metabolizing the contaminants immediately upon injection. But what benefit does bioaugmentation provide in the long term? And how much benefit does bioaugmentation provide over biostimulation by adding nutrients to the native organisms?

A client of CL Solutions completed a bench-scale study to answer these questions.  A bench-scale study was preferred to a field study because it removes the potential distribution and time-lag issues associated with the distances between injection and monitoring locations in the field.

Samples of petroleum-contaminated soils were obtained and separated into split samples for treatment with microbes and nutrients. Some were untreated for comparison.  Samples were tested for petroleum concentrations, including C-fraction concentrations after 30, 40 and 60 days.  Heterotrophic populations were measured at 40 and 60 days.

The tests showed the following results in the early stages:

  • All of the treated samples showed more than 80% total petroleum reduction in the first 30 days.
  • The sample treated with nutrients only had the same level of petroleum removal as the bioaugmented samples in the first 30 days.
  • The heterotrophic population of the biostimulated sample was as high as in the bioaugmented samples at 40 days.

After 30 days the situation changed.

  • The bioaugmented microbial population continued to increase  after 40 days and may have increased by a factor of 100 times.  Meanwhile, the biostimulated population appeared to stall.
  • The petroleum removal continued in the bioaugmented samples and reached as high as 93% removal.  In comparison the biostimulated sample stalled at 82% removal.
  • The difference appears to be that the bioaugmented samples removed the C-21 to C-35 concentrations at a much higher rate than the biostimulated sample.
  • Phenanthrene was target chemical for bioremediation. The biostimulated sample showed 39% removal while the bioaugmented samples showed complete removal to BDL.

Overall, the superior performance of the bioaugmented samples appears to be related to having a greater metabolic range that removed the heavier hydrocarbon fractions.  Microbes with the extended metabolic range could continue to multiply as they grew on the heavy hydrocarbon fraction.  The results are consistent with field results showing the recalcitrance of heavier hydrocarbon fractions and compounds like naphthalene and phenanthrene under natural attenuation.

Contact CL Solutions for more information and insights.

 

 

 

 

 

BTEX and Naphthalene Bioremediation to BDL by Petrox Microbes

Case Study:
Orange County Fire and Rescue Station 81, Orlando, Florida

Oculus Number 8520434

Petrox was used to treat the residual petroleum contamination in ground water after the leaking tank was removed.  The petroleum contamination exceeded applicable standards for benzene, toluene, ethylbenzene, and xylene (BTEX) and naphthalene.  Petrox was injected into the ground water through 28 injection points covering a plume area of approximately 6,300 square feet.   Petrox injections were completed on June 18, September 11, and November 1, 2002.

Prior to bioaugmentation 100 pounds of ORC was added to provide supplemental oxygen for the bioremediation.  After verifying the dissolved oxygen concentration was more than 1.0 mg/l, the site was ready for bioaugmentation.

During the first injection 10 drums of Petrox were injected to cover the full plume.  As the area of contamination decreased, less Petrox was injected.  Five drums were injected in a focused application on September 11 and November 1, 2002.

Quarterly monitoring was completed during and after the inoculation to determine the bioremediation results.  The cleanup goals were achieved in the source area after the first inoculation.  The contamination persisted, however, in the down gradient wells.  The cleanup goals were achieved in the down gradient monitoring well after the third injection, but there was subsequent rebound.  After full distribution of Petrox was reached throughout the plume, the BTEX and naphthalene concentration were below detection limits (BDL), and cleanup goals were achieved and maintained. 

Please refer to the table below for the ground water monitoring results.

Monitoring Well Date Benzene Toluene Ethylbenzene Total Xylenes Naphthalene
MW-7 Source Area 6/12/2000 5.0 46.0 18.0 90.0 24.0
6/13/2001 39.0 272.0 167.0 526.0 26.0
3/14/2002 21.0 19.0 102.0 266.0 39.0
6/5/2002 ORC Added
6/18/02 10 Drums of Petrox Added
7/14/2002 <1.0 <1.0 <1.0 <2.0 <1.0
9/11/2002 <1.0 <1.0 <1.0 <2.0 <1.0
9/11/02 5 Drums of Petrox Added
10/7/2002 <1.0 <1.0 <1.0 <2.0 <1.0
11/1/02 5 Drums of Petrox Added
12/2/2002 <1.0 <1.0 <1.0 <2.0 <1.0
1/9/2003 <1.0 <1.0 <1.0 <3.0 <5.0
4/17/2003 <1.0 <1.0 <1.0 <2.0 <1.0
             
MW-8

Down Gradient

6/12/2000 2.0 72.0 21.0 109.0 39.0
6/13/2001 14.8 677.0 207.0 1292.0 113.0
3/14/2002 71.0 1198.0 357.0 2408.0 193.0
6/5/2002 ORC Added
6/18/02 10 Drums of Petrox Added
7/15/2002 19.0 515.0 170.0 690.0 39.0
9/11/2002 <1.0 3.7 3.8 16.4 <1.0
9/11/02 5 Drums of Petrox Added
10/7/2002 6.4 2.3 4.7 23.8 15.0
11/1/02 5 Drums of Petrox Added
12/2/2002 38.0 515.0 95.0 460.0 10.0
1/9/2003 <1.0 <1.0 <1.0 <3.0 <5.0
4/17/2003 <110.0 1060.0 285.0 1120.0 65.0
4/29/2004 <1.0 <1.0 <1.0 <1.0 <1.0
9/1/2004 <1.0 <1.0 <1.0 <1.0 <1.0
12/1/2004 <1.0 <1.0 <1.0 <1.0 <1.0
3/21/2004 <1.0 <1.0 <1.0 <1.0 <1.0

Pesticide Bioremediation – Landfarming Application for DDD, DDE and Toxaphene

Petrox® bioremediation was used to remediate pesticide-contaminated soil at an industrial location in California.

Soil Remediation

The soil contamination consisted of pesticides including 4,4-DDD, 4’4-DDE and toxaphene.  Soil samples were sent to CL Solutions for bench-scale treatability studies.   The following table shows the  maximum detected concentrations and the treatment results.

Contaminant
Untreated Concentrations (ug/Kg)
Post-treatment concentrations (ug/Kg)
4,4-DDD
390
250
4,4-DDE
380
220
Toxaphene
8,500
440

After the bench-scale verification, full-scale bioremediation was implemented.  The contaminated soil was placed in two stockpiles and treated with Petrox. The following table shows the pre- and post-treatment results.

Contaminant Concentrations (ug/Kg)
Contaminant
Pile 1
Pile 2
Before
After
Before
After
4,4-DDD
310
170
14
nd ( <5)
4,4-DDE
810
300
8.7
nd  (<5)
Toxaphene
12,000
7,300
380
nd (<5)

Conclusions

The Petrox treatment successfully reduced the concentrations of pesticide contaminants in the soil stockpiles.  For additional information or assessment of applicability to your site contact CL Solutions.

Bioremediation Product Safety

CL Solutions wants to assure you that our products are safe for human health.  All of our products are manufactured under strict health and safety protocols.  Starting with seed cultures, that are known to be safe, from known sources the cultures are grown in sterile sealed tanks.  The finished products are also stored in laboratory-clean areas.  Manufacturing and laboratory areas have separate ventilation systems to prevent product contamination.

Some other manufacturers of bioremediation products use open-top growing tanks that can be contaminated by atmospheric organisms.  These manufactures do not control the type of organisms that may be present in their products.

CL Solutions’ products are tested for viability and the absence of pathogens prior to shipping.  Not all bioremediation manufacturers follow the high QA/QC protocols of our manufacturer.

You can be confident with our bioremediation products that you will get only beneficial microbes and the products will be pathogen free.  These safety measures protect our workers, your workers, and people who live or work at the site.

 

 

 

New Custom Blend Available for Denitrification

CL Solutions has provided Petrox DN for denitrification for many years.  Petrox DN is a freeze-dried consortium that requires hydration before application.  CL Solutions now provides a custom blend of microbes in a dry powdered form with denitrification capabilities. This dry blend makes for more convenient storage and use.  Additional organisms in the consortium can degrade ammonium and organics including petroleum hydrocarbons, fats, carbohydrates, proteins, starches and cellulose.  These benefits make the custom blend a powerful tool for bioremediation of liquid waste in fixed facility treatment or environmental applications.

Call CL Solutions for more infomation or a site evaluation at 513-284-5940.