Fast Bioremediation Eases Site Development in Boston

Underground storage tank (UST) leaks from a former gas station contaminated shallow ground water under a parking lot for a commercial building.  The UST contamination was found during trenching for utilities.  As the presence of contamination prevented further property development, fast remediation was important to the stakeholders.

The size of ground water plume that resulted from leaching soil contaminants was estimated to be 5,000 square feet.    The contamination was mainly diesel-range petroleum constituents, with the highest concentrations in the aliphatic range, but there were also scattered detections of xylene, toluene, and ethylbenzene.

Petrox bioremediation was implemented in the ground water.  Three units of Petrox (165 gallons) were injected into the contaminated ground water through vertical injection wells located up gradient of the monitoring wells.

After a single inoculation of Petrox, the contaminant concentrations were reduced across the property.  The following table shows the overall reduction in both the volatile and semi-volatile range hydrocarbons.

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Fast, Easy Drainage Ditch Cleanup

Petrox bioremediation of surface spills and TPH accumulation in drainage ditches and maintenance areas is simple. Using a simple manual sprayer, the Petrox is applied to the soil surface. The Petrox microbes begin bioremediation immediately to enhance natural digestion of the petroleum, like probiotics for petroleum destruction.  Unlike detergents that wash the visible oil deeper in the soil, Petrox microbes destroy the all of the oil.

The following chart and table show the results of the application of Petrox to petroleum-contaminated 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.  A second application to the 30 ft. north area reduced the concentration even more.

The problem was solved for a total Petrox cost of $600.

houston soil treatment chart houston soil treatment table

 

 

 

Improve Soil Flushing and LNAPL Removal with Petrox EC

Petrox EC is a product that combines a surfactant with petroleum-degrading microbes to improve separate phase oil recovery and bioremediation of residual oil.  The combined approach improves the rate of oil removal from soil and other subsurface media and establishes a beneficial petroleum-degrading microbial population that will treat tightly bound or deeply penetrated oil.

Petrox EC has been used in combination with periodic LNAPL extraction by pumping or bailing.   In field applications the surfactant effect has increased the LNAPL recovery rate by more than 10 fold.

Petrox EC has also been used to improve the efficiency of air sparging by flushing oil from the sediment surface for sparging and vapor phase recovery.

Field Bioremediation Rates For Petroleum and Solvents

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

 

CL-Out Bioaugmentation Saves Time and Money

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).