Bioremediation of Industrial Fill

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Historical industrial sites often have deposits of fill material containing a wide range of organic contaminants.   Perched ground water  present in the base of the fill is usually impacted by the contaminants and may provide a mechanism for off-property migration of the contaminants.  The organic contaminants are wide spread throughout the fill without a well defined source area.  Cost-effective remediation is difficult with this combination of conditions.

Bioaugmentation with CL-Out or Petrox can remove the contaminants from the fill and perched water by destruction in place.  The organisms in CL-Out and Petrox can metabolize a wide-range of organic chemicals at concentrations from separate-phase layers to part per trillion levels.  Soil and ground water contaminants are addressed simultaneously though injection of the microbes without disturbing the  site operations.

The following table shows typical results from a single application of Petrox to contaminated soil and perched ground water on July 10, 2011.  The remediation progress was tracked by ground water monitoring because it was the easiest sampling method once wells were in place.Industrial Fill TreatmentThe results show that within 30 days the contaminant concentrations in perched water were reduced by 50%.  After 60 days there was slight rebound in come of the contaminants, showing that more soil treatment may be necessary if lower cleanup goals needed to be maintained.

 

 

Field Bioremediation Rates For Petroleum and Solvents

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The success of bioaugmentation depends on effective distribution of the beneficial microbes.  If the target population is achieved, the remediation rate ranges from 50% to over 99% removal.  The rate appears to be independent of the contaminant starting concentrations.  This indepedence is the advantage of bioaugmentation.  Through bioaugmentation the density of beneficial organisms is sufficient for frequent reactions with high or low contaminant levels.  The following chart shows the results of a single application of bioaugmentation at 11 sites in different states, with different contaminants.

remediation rates with bioaugmentation

 

The chart also suggests that the results are not time dependent.  The apparent time independence may be because the reactions are completed early and because these were grid applications with the monitoring locations within the bioaugmented area instead of downgradient where the results would depend on dispersion rates.

The USEPA tested the degradation rate of oil using Munox SR for NCP listing.  The degradation rate exceeded most comparable products with 95% removal of alkanes and 89% removal of aromatics in 28 days.  The NCP test results are available at https://19january2017snapshot.epa.gov/sites/production/files/2013-08/documents/notebook.pdf

 

Bioaugmentation to Improve Oxygen Delivery Results

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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

Bioremediation of Dinitrotoluene

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Dinitrotoluene (DNT) may occur in soil and ground water as the result of spills and historical use of the chemical as a solvent and industrial intermediary or as a residual of explosives at military facilities.  CL Solutions and SpecPro, Inc. conducted a treatability study to determine the effectiveness of CL-Out microbes in the removal of DNT from contaminated ground water at the Badger Army Ammunition Plant (BAAP) near Baraboo, Wisconsin.  The treatability study showed the removal of all six isomers of DNT, with a 53% to 91% removal in 21 days.  Intermediate by-products were detected only temporarily during the treatability study.  For more detailed information call CL Solutions.

CL-Out Bioaugmentation Saves Time and Money

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By switching from active extraction to in situ CL-Out® bioremediation, In Control Technologies, Inc. of Houston, Texas saved their client $100,000s in on-going operation and maintenance costs.  The Site was a shopping center where soil and ground water were contaminated by dry cleaning chemicals.  A dual phase extraction system was installed and operated for 9 years.  The dual phase system reduced the total CVOCs by 70%, but the contaminant removal rate  reached the limit of cost effectiveness.

By switching to bioremediation, the client avoided $75,000 on-going annual operation and maintenance cost with a $20,000 investment in bioremediation. CL-Out® bioremediation reduced the residual contamination by more than 98% in less than 90 days.  This case study was reported at the 9th In Situ and On-Site Bioremediation Symposium, 2007

Irwin Engineers, Inc., of Natick, Massachusetts has undertaken a similar approach to reduce on-going pump and treat remediation costs at a site of perchlorate contamination.  Irwin Engineering presented that case study at the AEHS Soils, Sediment, Water and Energy Conference (2013).