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Tag Archive for: bioremediation

Benzo(a)pyrene Bioremediation Using Custom Blend Microbes

May 3, 2019
03 May 2019
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Benzo(a)pyrene is a difficult remediation challenge. It is resistant to biological and chemical destruction and extraction from soil.  CL Solutions Custom Blend microbes, however, have successfully remediated benzo(a)pyrene and other PAHs in soil during ex situ land farming treatment.  By placing the contaminated  material in windrows, controlling the temperature and moisture, the addition of Custom Blend microbes has reduced the benzo(a)pyrene concentration by as much as 330 ug/kg/day.

The same approach works on high as well as low concentrations.  At a site in Oregon, the benzo(a)pyrene concentration was reduced from 140 ug/Kg to below detection limits in 7 days.  At a site in Ohio, the benzo(a)pyrene concentration was reduced from 28,000 ug/kg to 3.8 ug/Kg in 60 days.  At both sites, Custom Blend microbes effectively treated the full suite of PAHs along with the benzo(a)pyrene.

in Chemical Industries, Custom Blend microbes, News, Petroleum Remediation /by

Houston, Texas Dry Cleaner Site Remediation in Less than 6 Months

May 1, 2019
01 May 2019
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Summary

Dry cleaning solvents were found in the ground water adjacent to a dry cleaning facility located in a commercial shopping center in Houston, Texas. InControl Technologies, Inc. of Houston, Texas was the environmental consulting firm that completed the site investigation and remediation.

CL-Out® bioremediation was implemented to reduce the mass of contamination in the source area. CL-Out® is a consortium of Pseudomonas sp. that produces constitutive enzymes to cometabolize PCE and other halogenated aromatic compounds.  Dextrose is added with CL-Out® to provide a substrate for microbial growth.  Application of CL-Out® bioremediation at this site achieved the cleanup goals in less than 6 months.  The cleanup goals were maintained for more than one year to achieve project closure.

Geology and Hydrogeology

The site is located on a coastal plain where the geology is characteristically interbedded silt and sand deposits overlying a thick cohesive clay formation.  The affected aquifer was a silty sand zone approximately 40 to 55 feet below grade.  The aquifer ground water yield was low and the ground water was classified as Class 3 ground water.

The ground water aquifer was naturally aerobic.  Dissolved oxygen measurements taken from monitoring wells in the source area ranged from 2.6 to 5.4 mg/L.  The oxidation-reduction potential (ORP) measured in the same wells ranged from 89 to 303 mveq.  The aerobic conditions of the aquifer favored aerobic CL-Out® cometabolism.

Contamination

Monitoring wells were installed on all sides of the dry cleaners, but access restrictions prevented the installation of monitoring wells inside the building.  The site layout including sampling and treatment locations are shown on the attached figure.  PCE and concentrations of daughter products, including TCE and cis-1,2 DCE were found in ground water adjacent to the dry cleaners and down gradient businesses.  PCE concentrations in the source area ranged from 0.260 mg/L to 0.860 mg/L prior to remediation.  The TCE concentrations ranged from 0.031 mg/L to 0.085 mg/L. The cis-1,2 DCE concentrations ranged from 0.096 mg/L to 0.67 mg/L.  Vinyl chloride was not detected prior to remediation.  The sampling results are summarized in the attached table.  The contamination plume was estimated to be 7,500 square feet.

While the presence of breakdown products suggested natural attenuation by biological destruction was occurring, bioaugmentation was implemented to accelerate the site remediation.

Remediation Design

CL-Out bioremediation was implemented in the ground water in the source area and accessible down gradient locations.  Most of the down gradient plume, however, was inaccessible for direct treatment.  Due to limited access, the down gradient areas were treated by attenuation as the source mass was destroyed up gradient.  Eight temporary injection wells were installed around the dry cleaner building and source area.  The injection points were set with 10-foot-long screened intervals from 40 to 55 feet deep.  The temporary injection wells allowed for repeat inoculations without additional drilling costs.

CL-Out® organisms were injected into the affected aquifer in two events.  On April 15 and June 30, 2005, 50 gallons of hydrated CL-Out® were injected into the temporary injection wells.   Approximately 10 gallons of CL-Out® solution was gravity fed into each injection well without additional pressure.

Monitoring Results

Ground water samples were taken from the monitoring wells for laboratory analysis for the contaminants and field measurements of dissolved oxygen and ORP.  The field parameters show that after application of CL-Out® bioaugmentation the dissolved oxygen levels and ORP decreased.  This decrease confirms aerobic metabolism was taking place.  The PCE and TCE concentrations also decreased immediately following the injections.  However, there was also an increase in the cis-1,2 DCE concentrations following the bioaugmentation.  The cis-1,2 DCE concentrations decreased to the pretreatment levels in each of the source area wells except MW-4 during the post treatment monitoring.  Vinyl chloride was detected in MW-1 and occasionally in MW-8 and MW-11 after bioaugmentation, but persisted in only MW-1.  Maintaining aerobic conditions would have reduced or prevented the accumulation of the daughter products. Nevertheless, the daughter product concentrations did not exceed the Class 3 Standards applicable to the site.

The following tables show the PCE concentration trends during remediation.  MW-2, shows the concentration of PCE in a well outside of the treatment area remained relatively constant during the same time.

 

Ground Water Sampling Results Summary Table

Monitoring Date PCE TCE cis-1,2 DCE VC D.O. ORP
Well   (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mveq)
GW Class 3 PCL 0.5 0.5 7 0.2    
MW-1

 

 

 

 

 

 

 

 

 

 

 3/24/04 0.800 0.090 0.500 <0.001 5.8 131.7
8/13/04 0.700 0.100 0.510 <0.001 5.8 134.3
11/23/04 0.660 0.045 0.550 <0.005 5.4 154.6
3/30/05 0.750 0.067 0.550 <0.001 5.0 303.5
First CL-Out Inoculation
6/2/05 0.230 0.045 1.100 <0.001 0.9 -131.1
 Second CL-Out Inoculation
9/19/05 0.065 0.044 0.900 0.0032 3.0 -105.4
12/29/05 0.016 0.0084 0.650 0.021 3.0 -30.8
3/17/06 0.0054 0.0021 J 0.600 0.030 0.9 -104.7
6/8/06 0.018 0.018 0.120 0.039 1.2 -107.7
MW-4

 

 

 

 

 

 

 

 

 

 

 3/23/04 0.540 0.036 0.110 <0.001 4.9 128.1
8/13/04 0.760 0.039 0.140 <0.001 5.0 128.0
11/23/04 0.530 0.026 0.130 <0.005 5.2 141.2
3/30/05 0.410 0.019 0.096 <0.001 5.1 220.3
 First CL-Out Inoculation
6/2/05 0.330 0.019 0.120 <0.001 4.2 -79.3
Second CL-Out Inoculation
9/19/05 0.390 0.028 0.140 <0.0003 3.4 -81.8
12/29/05 0.410 0.031 0.200 <0.001 2.8 -20.8
3/17/06 0.089 0.021 0.410 <0.0003 0.6 -102.6
6/8/06 0.250 0.032 0.300 <0.00017 1.1 -103.2
MW-8

 

 

 

 

 

 

 

 

 

 8/23/04 0.580 0.046 0.220 <0.001 3.1 88.7
11/23/04 0.260 0.028 0.280 <0.001 4.7 157.8
3/30/05 0.700 0.039 0.330 <0.001 3.7 287.0
 First CL-Out Inoculation
6/2/05 0.150 0.031 0.250 <0.001 3.0 95.9
Second CL-Out Inoculation
9/19/05 0.045 0.0095 0.920 0.00051 J 4.2 24.1
12/29/05 0.011 0.0013 0.420 0.0027 3.3 33.6
3/17/06 0.0045 J <0.0023 <0.0029 <0.003 1.1 34.4
6/8/06 0.0024 J <0.00025 0.300 0.0024 J 1.0 -106.3
MW-11

 

 

 

 

 

 

 

 

 

 8/13/04 0.580 0.085 0.420 <0.001 2.8 129.1
11/23/04 0.580 <0.2 0.480 <0.2 3.3 150.5
3/30/05 0.860 0.074 0.670 <0.001 2.6 278.3
First CL-Out Inoculation
6/2/05 0.270 0.031 0.490 <0.001 2.8 161.3
 Second CL-Out Inoculation
9/19/05 0.180 0.023 0.720 0.00081 J 3.5 77.9
12/29/05 0.096 0.0083 0.120 0.0017 2.9 61.9
3/17/06 0.046 0.0062 J 0.057 <0.003 1.5 108.2
6/8/06 0.056 0.007 0.470 0.0039 J 0.9 62.2

After one year, the contaminant concentrations continued to meet the cleanup goals in the source area and a Certificate of Completion was recommended for the project.  The total CL-Out® remediation cost was less than $10,000.  More information can be obtained by contacting CL Solutions at 513-284-5940 or www.cl-solutions.com.

in Chlorinated Solvent Remediation, CL-Out, Dry Cleaners /by

Soil Bioremediation at Dry Cleaners

April 12, 2019
12 Apr 2019
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Permanently remove vapor intrusion risk

Soil bioremediation is a more effective strategy for managing the vapor intrusion risk at dry cleaners where solvents have contaminated soil or shallow ground water.  Soil bioremediation quickly eliminates the problem, while long-term vapor mitigation ties up resources in on-going operation, maintenance and monitoring costs.  Soil bioremediation eliminates the source of  vapors entering the cleaners and adjoining properties.  The source removal restores the full property value without disrupting operations.

CL-Out microbes have been used at many sites in the US and Canada to remove PCE contamination from soil at dry cleaners and other industries where solvents are used. CL-Out is a consortium of microbes selected for their ability to cometabolize chlorinated solvents under aerobic conditions.  The microbes are pumped into the soil through small boreholes in the building or surrounding area.  Once in the soil, the microbes produce metabolic enzymes that convert the PCE into carbon dioxide and water without generating harmful by products.

The following case studies are examples of how quickly and cost effectively CL-Out bioremediation removes the soil contamination:

Chicago, Illinois

CL-Out bioremediation reduced concentrations of dry cleaning solvents in soil to allow for the redevelopment of a property into luxury condos.  After the old building was removed, the contractor mixed CL-Out microbes into the PCE-contaminated soil.  After 90 days the soil was tested to verify success.

The 90-day sampling showed that the remediation met the site cleanup standards.  PCE was reduced by more than 95% from a maximum of 3,100 mg/kg to less than 120 mg/kg.  A “No Further Action” letter was submitted to IEPA.  The CL-Out cost for the project was $13,000.

Orange County, California

At a site in southern California, the soil and ground water contamination was removed at at operating dry cleaners without interrupting the business operations.  CL-Out microbes were injected into the soil and ground water through small-diameter borings.  Inside the building, hand-dug borings less than 3-inches in diameter were used for the treat the soil. Two drums of CL-Out microbial solution were injected into 80 cubic yards of contaminated soil.

After 30 days soil sampling showed the PCE concentration was reduced by 85% from 775 ug/Kg to 115 ug/Kg.  No daughter product were generated during the bioremediation.

The ground water was treated simultaneously and the contaminant concentrations were reduced by more than 90%.

The cost for CL-Out to treat both soil and ground water was $9,500.

Click here to view the full case study.

Call CL Solutions to discuss removing the vapor intrusion risk at your property.

 

in Chlorinated Solvent Remediation, CL-Out, Dry Cleaners /by

PAH Bioremediation

March 11, 2019
11 Mar 2019
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The results of a recent bench-scale test confirmed the effectiveness of a special blend of CL Solutions’ microbes formulated for PAH bioremediation.  The test results showed that after two weeks, the total concentration of 15 PAH compounds decreased by 85% from a total of 358 mg/kg to 50.9 mg/kg.  Benzo(A)pyrene is often a most difficult PAH to remove. The test showed that the custom blend reduced the benzo(A)pyrene concentration from 24.5 mg/kg to 3.68 mg/kg.  Tests will continue to determine whether even greater effectiveness can be achieved over 30 days.

in Gas Stations, Industrial Maintenance, Industrial Sites, Oil Fields, Oil Spill Remediation, Petroleum Remediation, Petrox, Storage Tanks /by

TCE Remediation With CL-Out® Bioremediation and Dual-Phase Extraction

November 15, 2018
15 Nov 2018
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Case Study: Industrial Site, Houston, Texas

Site Summary
CL-Out® bioaugmentation was implemented in combination with dual phase extraction at an industrial site near Houston, Texas to remove trichloroethylene (TCE) from ground water. The overlying contaminated soil was excavated, but perched ground water and a deeper aquifer had TCE concentrations greater than 10,000 µg/L. A dual-phase vacuum extraction system was installed to control the ground water gradient and increase distribution of the CL-Out® organisms in the aquifer. The TCE concentrations were reduced by 99.9% in one year.

Geology and Hydrogeology
The site is located on coastal plain sediments characteristically interbedded sands, silts and clays. The first impacted ground water was a thin perched layer 16 to 18 feet below ground surface. A more transmissive, water bearing zone was at 25 to 30 feet deep. Both water-bearing layers and the interbedded fine-grained layers had TCE concentrations above regulatory standards.

Contamination
High concentrations of TCE were present in perched and deeper ground water. Prior to treatment, a small area of soil less than 500 square feet had TCE concentrations greater than 20,000 µg/L. The underlying impacted perched ground water area was the same size and had TCE concentrations up to 30,000 µg/L. The TCE migrated laterally in the underlying deeper ground water where the TCE concentrations were greater than 10,000 µg/L. The area of the deeper ground water plume was approximately 30,000 square feet.

Remediation
The contaminated unsaturated soil was excavated for treatment to the perched ground water. The perched ground water was treated by a combination of potassium permanganate and vapor extraction. The deeper aquifer was treated by a combination of dual-phase extraction and CL-Out® bioremediation.

CL-Out® was applied eight times between January, 2010 and February, 2011. During each application 55 to 110 gallons of CL-Out® was injected into the ground water. The dual-phase extraction system was used to control the ground water gradient and induce greater distribution of the CL-Out® microbes. Periodic plate count analysis of the microbial population in the treated aquifer was completed to guide where and when the CL-Out® population should be supplemented. The repeat applications were on approximately 4 to 6 week intervals.

Results
Following one year of bioaugmentation, the contaminant concentrations were reduced by more than 99%. The daughter products caused by incomplete natural breakdown were removed as well as the TCE. The following table shows the contaminant concentration trends in the treatment area.

in Chemical Industries, CL-Out /by

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