Site Summary
CL-Out® perchlorate bioremediation was implemented at a confidential manufacturing site to remediate perchlorate concentrations in soil and ground water. After careful treatability testing and a source area pilot study, full-scale application of CL-Out® bioremediation reduced the perchlorate concentration in the soil by more than 99.9% and in ground water by approximately 99%. The remediation provided immediate risk reduction and mitigated potential off-site migration. Current results trend toward achieving applicable standards in soil and ground water in an accelerated timeframe. The property sold without environmental impairment upon completion of bioremediation.
Project Design and Implementation
Following the discovery of perchlorate in soil and ground water near a former storage area, a hydraulic extraction system was installed to contain the perchlorate ground water plume. CL-Out® bioremediation was then tested to determine applicability to remediate the site by in situ treatment and to eliminate the need for ground water containment. After a successful treatability study, a pilot study was implemented in the source area to test field applicability and to reduce concentrations in the impacted source area soil.
One of the key factors in CL-Out® cometabolism of perchlorate at this site was that CL-Out® organisms were able to reduce sequentially the oxygen and nitrate prior to perchlorate. The initial nitrate concentrations were typically much higher than the perchlorate concentrations. The perchlorate concentration did not decrease until the nitrate concentration decreased to less than the perchlorate concentration. One of the benefits of the CL-Out® organisms was this ability to utilize these different electron acceptors.
The source area soil was treated with the application of CL-Out® through a surface infiltration system. Five to 10 gallons of CL-Out® was applied through a percolation trench three times and allowed to seep through 30 cubic yards of impacted soil. An extraction well recovered the ground water. After six months the perchlorate concentration in the source area soils were reduced from 1,800 mg/kg to 8 mg/kg and to 0.35 mg/kg after 8 months.
Ground water samples taken from the source area extraction well showed a decrease in perchlorate concentrations during the soil treatment. Prior to the soil treatment the extracted ground water had a perchlorate concentration of 0.3 mg/L. At 6 months the perchlorate concentration in ground water decreased to 0.2 mg/L. After 8 months, the perchlorate concentration decreased to 0.1 mg/L. These results confirmed that the perchlorate was destroyed in situ and not flushed from the soil.
After successful source treatment, CL-Out® bioremediation was initiated in the ground water plume. Perchlorate is present in both an unconsolidated overburden aquifer and bedrock aquifer. The perchlorate plume is approximately 3 acres with a maximum detected concentration greater than 300 mg/L. High nitrate concentrations were associated with the high perchlorate concentrations. The aquifer is aerobic with high dissolved oxygen levels in both the overburden and bedrock aquifers. The application of CL-Out® cometabolism first reduced the oxygen and nitrate prior to reducing the perchlorate. The ground water pH was low and required buffering to prevent potential microbial growth limitations.
The aquifer amendments and bioaugmentation solution were introduced into the aquifer through temporary injection wells in lines at key locations perpendicular to the ground water flow. Before the bioaugmentation, a weak base was added to buffer the ground water pH. Then, CL-Out® microbes were injected in the aquifer in a solution with dextrose as a cometabolic substrate.
The unconsolidated aquifer was inoculated with CL-Out® through nine injection points near the plume front and seven injection points down gradient from the source area. Twenty-five to 110 gallons of CL-Out® were injected near the source area in three events between July and November 2012. One hundred total gallons of CL-Out® were injected near the plume front between August and November 2012.
Ground water in bedrock was treated by inoculation with CL-Out® at one injection point on three occasions. The inoculation volume was 25, 7 then 5 gallons in November 2012, June and July 2013.
Results
Periodic post–treatment ground water samples were taken from several monitoring wells to track the progress of bioremediation and to monitor the microbial population and growth conditions. In eight months, the perchlorate concentration in the unconsolidated aquifer was reduced from 128 mg/L to 3.4 mg/L immediately down gradient of the source area and from 220 mg/L to 39 mg/L farther down gradient. The perchlorate concentration near the first set of plume injection points decreased from 100 to <1.0 mg/L. At the plume front the perchlorate concentration decreased from 10 to 5.0 mg/L. The perchlorate concentration in the bedrock decreased from an average of 5 mg/L pretreatment to <0.3 mg/L.
As the perchlorate was removed, the CL-Out® microbes also removed the nitrate. Down gradient of the source area the nitrate concentration decreased from 105 mg/L to <1.0 mg/L. Farther down gradient the nitrate concentration decreased from 200 mg/L to 5 mg/L.
Field application of CL-Out® has rapidly reduced mass and concentrations by orders of magnitude, achieving plume containment and significant savings over hydraulic containment and ex-situ treatment. The remediation is in progress, but these early results confirm the successful application of CL-Out® bioremediation to high concentrations of perchlorate.
Pesticide Bioremediation with Petrox®
/in Chemical Industries, Petrox/by Mike SaulSite Summary
Petrox® bioremediation was used to remediate dieldrin and other pesticides at a site in Pensacola, Florida. The remediation progressed in stages including a bench-scale treatability study and field pilot study prior to full-scale remediation. The full-scale remediation is also staged to take full advantage of the benefits of each application of Petrox® bioremediation prior to the next application. The remediation is in progress, but this case study reports the significant progress made in reducing the size of the impacted ground water plume and the contaminant concentrations.
Geology and Hydrogeology
The site is located on coastal plain sediments. The sediments are fine to medium-grained quartz sand to approximately 40 feet deep, where a medium to coarse grained sand layer is encountered. The coarse-grained layer is approximately five feet thick. The coarse-grained layer overlies a fine to medium-grained sand layer with interbedded discontinuous clay lenses. The sediments form a thick, unconfined aquifer. The water table is at approximately 45 feet below grade.
Contamination
Chlorinated pesticides were used at the site from 1982 to 1984. The release is assumed to be from the accumulation of small spills during on site mixing operations. The impacted soil was located on the property and concentrated in a drainage swale. The pesticides leached from the soil into the ground water forming a plume that was approximately 2,000 feet long and 200 feet wide. Soil source removal was conducted in August 2005 when a total of 1,272 tons of soil were excavated and disposed off-site. Bioremediation was selected to remediate the residual impacted soil and ground water.
Remediation
Petrox bioremediation was applied to the on-property source area and a mid-plume down gradient area. The down gradient plume treatment area was at a set of three injection wells 425 feet from the source area and up gradient from a cluster of monitoring wells.
Three full-scale applications of bioaugmentation were completed. The initial application in November 2011 was 1,540 gallons of Petrox solution injected into soil and 7 seven injection wells in the source area, and 3 mid-plume injection wells near the CW-13 well cluster. The injection in February 2012 was 990 gallons of Petrox solutions in 6 source area wells and 3 down gradient wells near the CW-13 wells. The third injection was 330 gallons of Petrox solution in the same 3 down gradient wells.
Dieldrin Plume Before Bioremediation
Dieldrin Plume After Bioremediation
Following Petrox® bioaugmentation the source area dieldrin concentrations were reduced from a maximum of 9.9 µg/L to 0.47 µg/L. The down gradient treatment reduced the dieldrin concentrations over an area of more than one acre by at least 90%. Overall the size of the plume was reduced by about one half and concentration by 90% in less than one year.
Perchlorate Bioremediation in Soil and Ground Water
/in CL-Out/by Mike SaulSite Summary
CL-Out® perchlorate bioremediation was implemented at a confidential manufacturing site to remediate perchlorate concentrations in soil and ground water. After careful treatability testing and a source area pilot study, full-scale application of CL-Out® bioremediation reduced the perchlorate concentration in the soil by more than 99.9% and in ground water by approximately 99%. The remediation provided immediate risk reduction and mitigated potential off-site migration. Current results trend toward achieving applicable standards in soil and ground water in an accelerated timeframe. The property sold without environmental impairment upon completion of bioremediation.
Project Design and Implementation
Following the discovery of perchlorate in soil and ground water near a former storage area, a hydraulic extraction system was installed to contain the perchlorate ground water plume. CL-Out® bioremediation was then tested to determine applicability to remediate the site by in situ treatment and to eliminate the need for ground water containment. After a successful treatability study, a pilot study was implemented in the source area to test field applicability and to reduce concentrations in the impacted source area soil.
One of the key factors in CL-Out® cometabolism of perchlorate at this site was that CL-Out® organisms were able to reduce sequentially the oxygen and nitrate prior to perchlorate. The initial nitrate concentrations were typically much higher than the perchlorate concentrations. The perchlorate concentration did not decrease until the nitrate concentration decreased to less than the perchlorate concentration. One of the benefits of the CL-Out® organisms was this ability to utilize these different electron acceptors.
The source area soil was treated with the application of CL-Out® through a surface infiltration system. Five to 10 gallons of CL-Out® was applied through a percolation trench three times and allowed to seep through 30 cubic yards of impacted soil. An extraction well recovered the ground water. After six months the perchlorate concentration in the source area soils were reduced from 1,800 mg/kg to 8 mg/kg and to 0.35 mg/kg after 8 months.
Ground water samples taken from the source area extraction well showed a decrease in perchlorate concentrations during the soil treatment. Prior to the soil treatment the extracted ground water had a perchlorate concentration of 0.3 mg/L. At 6 months the perchlorate concentration in ground water decreased to 0.2 mg/L. After 8 months, the perchlorate concentration decreased to 0.1 mg/L. These results confirmed that the perchlorate was destroyed in situ and not flushed from the soil.
After successful source treatment, CL-Out® bioremediation was initiated in the ground water plume. Perchlorate is present in both an unconsolidated overburden aquifer and bedrock aquifer. The perchlorate plume is approximately 3 acres with a maximum detected concentration greater than 300 mg/L. High nitrate concentrations were associated with the high perchlorate concentrations. The aquifer is aerobic with high dissolved oxygen levels in both the overburden and bedrock aquifers. The application of CL-Out® cometabolism first reduced the oxygen and nitrate prior to reducing the perchlorate. The ground water pH was low and required buffering to prevent potential microbial growth limitations.
The aquifer amendments and bioaugmentation solution were introduced into the aquifer through temporary injection wells in lines at key locations perpendicular to the ground water flow. Before the bioaugmentation, a weak base was added to buffer the ground water pH. Then, CL-Out® microbes were injected in the aquifer in a solution with dextrose as a cometabolic substrate.
The unconsolidated aquifer was inoculated with CL-Out® through nine injection points near the plume front and seven injection points down gradient from the source area. Twenty-five to 110 gallons of CL-Out® were injected near the source area in three events between July and November 2012. One hundred total gallons of CL-Out® were injected near the plume front between August and November 2012.
Ground water in bedrock was treated by inoculation with CL-Out® at one injection point on three occasions. The inoculation volume was 25, 7 then 5 gallons in November 2012, June and July 2013.
Results
Periodic post–treatment ground water samples were taken from several monitoring wells to track the progress of bioremediation and to monitor the microbial population and growth conditions. In eight months, the perchlorate concentration in the unconsolidated aquifer was reduced from 128 mg/L to 3.4 mg/L immediately down gradient of the source area and from 220 mg/L to 39 mg/L farther down gradient. The perchlorate concentration near the first set of plume injection points decreased from 100 to <1.0 mg/L. At the plume front the perchlorate concentration decreased from 10 to 5.0 mg/L. The perchlorate concentration in the bedrock decreased from an average of 5 mg/L pretreatment to <0.3 mg/L.
As the perchlorate was removed, the CL-Out® microbes also removed the nitrate. Down gradient of the source area the nitrate concentration decreased from 105 mg/L to <1.0 mg/L. Farther down gradient the nitrate concentration decreased from 200 mg/L to 5 mg/L.
Field application of CL-Out® has rapidly reduced mass and concentrations by orders of magnitude, achieving plume containment and significant savings over hydraulic containment and ex-situ treatment. The remediation is in progress, but these early results confirm the successful application of CL-Out® bioremediation to high concentrations of perchlorate.
Easy Bioremediation of Oil Surface Spills
/in Gas Stations, Oil Spill Remediation, Petrox/by Mike SaulPetrox 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.
BTEX Remediation in Groundwater
/in Oil Spill Remediation, Petroleum Remediation, Petrox/by cyberviseBTEX Bioremediation
This project demonstrates the rapid bioremediation of BTEX components of petroleum with Petrox bioaugmentation. BTEX contamination in groundwater from a leaking underground storage tank was cost-effectively treated with two applications of Petrox.
The pre-treatment concentrations of Toluene and Xylene were 1,198ppb and 2,408 ppb, respectively. Ten units of Petrox aerobic microbes were injected into the ground water on about June 2, 2002. Within six weeks the concentrations decreased to 515ppb and 690 ppb, Toluene and Xylene, respectively. After a second inoculation in August 2002, the concentrations decreased to 3.7ppb and 16.4 ppb, respectively. There has been a slight rebound in Xylene to 23.8 ppb, and a third inoculation will be implemented to finish the treatment.
The cost to treat this quarter acre plume with Petrox was about $20,000.
Bioremediation of BTEX at an Industrial Site in Florida
/in News, Oil Spill Remediation, Petroleum Remediation, Petrox, Storage Tanks/by cyberviseBackground
Petrox® bioaugmentation was used to remediate ground water contaminated by benzene, toluene, ethylbenzene and xylene (BTEX) at an industrial facility in central Florida (Facility ID No. 8521705). The bioremediation was implemented in perimeter wells around the source area where air sparging and vapor extraction was implemented. This combined approach provided cost-effective, full-site remediation by using complementary technologies.
Remediation Approach and Results
Petrox® was introduced into the contaminated ground water in the perimeter of the source area plume by injection through temporary well points. Two applications of Petrox® were completed. The initial application was in December 2007 and a subsequent application was completed in April 2008. During each application 550 gallons of Petrox® microbial slurry were injected into the ground water through 19 injection points. The treatment covered an area of approximately 7,000 square feet.
The ground water treatment results were monitored by laboratory analysis of ground water samples for the contaminants of concern. The quarterly monitoring results after the applications showed an immediate and continuous decrease in the BTEX concentrations. The following chart shows the total BTEX concentrations in three quarterly sampling events after the implementation of Petrox® bioaugmentation.
Conclusions
This project demonstrates two of the benefits of aerobic bioaugmentation. Petrox® organisms were able to metabolize the BTEX compounds, which were initially at part per million levels, to below detection limits. Bioaugmentation provides active control of the site with hydrocarbon-degrading organisms compatible with air sparging and vapor extraction in the source area, where the contaminant concentrations persisted longer than in the bioaugmentation area.