Posts

How Sustainable Green Remediation Saves Time And Money

/in , /by

CL-Out Bioremediation Wins Green Remediation Recognition and Saves Time and Money

Sustainable, green remediation is recommended to reduce the environmental impact of the removal of existing soil or groundwater contamination.  It has the added benefit of reducing costs and accelerating remediation to save time.

Following the ASTM standards greener remediation best management practices, Irwin Engineering of Boston, Massachusetts saved time and money for their client in the removal of nitrate and perchlorate contamination using CL-Out bioremediation.  Most of the savings came from switching from ground water extraction and treatment using ion-exchange to in situ bioremediation.

Using best management practices saved the following amount of money:

  • Reused existing piping and structures – saved $10,000.
  • Switched from ground water extraction for thermal treatment to in situ bioremediation – saved $2-3 million.
  • Close delineation and remediation planning to reduce treatment volumes – saved $1-2 million.
  • On-site biological treatment of well development water – saved $15,000.
  • Used ion specific probes to optimize lab performance – saved $20,000.
  • Used vegetation testing to delineate plume in the wetland – saved $50,000.
  • Used horizontal wells for bioremediation injection where appropriate – saved $30,000.

Overall project savings $3 to $5 million.

Overall time savings 3 to 5 years.

The property was sold to a new owner and transferred without impairment.

 

Bioremediation of Phthalates

/in , , /by

Fast and Economical Phthalate Contamination Removal

Bioremediation of phthalates can reduce risks to human health and the environment.  Phthalates are a  a family of common industrial chemicals used in plastics and other consume products.  Phthalates can damage the liver, kidneys, lungs and reproductive system.  Petrox microbes can remove these contaminants from water or soil to reduce potential exposure to these risks.

Petrox bioremediation of phthalates has been demonstrated in field and laboratory studies to remove phthalates from soil and ground water.  Field application of Petrox bioremediation reduced bis(2-ethylhexyl)phthalate (BEP) concentrations from 650 ppm to 397  ppm in soil and 300 to 39 ppb in ground water at a site in Rochester, New York.  At the same site di-n-octylphthalate (DOP) in soil was reduced from 7.5 to 1.9 ppm. Click here to view the case study.

Dry Cleaner Bioremediation and Brownfield Redevelopment

/in , , , /by

Site Description

Dry cleaning solvent spills in a storage area lead to the contamination of soil and ground water on the property of a 50-year-old dry cleaners in the middle of a hot brownfield redevelopment.   After the contaminated soil was excavated for off site disposal to the most practical extent, residual perched ground water contamination impacted the redevelopment of the property.

The soil excavation was used as an infiltration gallery as part of a recirculating ground water recovery and treatment system.  The flushing reduced contaminant concentrations, but the levels were still far above the levels required to achieve no further action status.  CL-Out was added to the recirculating ground water and the cleanup goals were achieved in less than two years and were maintained through two years of  post treatment monitoring.

Site Characteristics

Geology and Hydrogeology

The site is on a fluvial terrace adjacent to the Ohio River.  The shallow soils are clayey silts to sit to eight feet deep.  An interbedded sandy zone that formed the first water-bearing zone was encountered from 8 to 12 feet deep.  Perched ground water occurred in the sandy zone at 12 feet below grade.

Ground Water Contamination

 The size of ground water plume that resulted from the spills was estimated to be 3,500 square feet.    The ground water contamination was mainly PCE with a maximum concentration of 11,000 ug/l prior to soil removal or ground water treatment.  The daughter compounds TCE and DCE were detected up to 17 and 12 ug/l respectively.  After three years of recirculation and flushing, the maximum PCE concentration was reduced to 2.3 ug/l and the daughter compounds were below detection limits.

Results

CL-Out bioaugmentation was implemented to supplement the flushing system.  By adding CL-Out on two occasions over two years, the contaminant concentrations were reduced to below drinking water standards.  During two years of post treatment monitoring the DCE concentrations rebounded to above the MCLs.  CL-Out bioaugmentation was implemented again and within three months the contaminant levels were below drinking water standards and remained below drinking water standards for nine months.  After post closure monitoring verified the cleanup goals would be maintained, the KDEP issued a “No Further Action” letter for the site.

The following chart shows the PCE contaminant trend in one of the key monitoring wells during the remediation and post closure monitoring.

Cost

The CL-Out cost during this remediation project was less than $10,000.

 

In-Situ Petroleum Bioremediation Rates With Petrox

/in , , , , , , /by

Recent data from field applications of Petrox bioremediation show degradation rates of 100 to 500 micrograms per liter (ug/ml) per day. These degradation rates are for total petroleum hydrocarbons or total BTEX, depending on the site monitoring requirements.

Achieving high degradation rates requires high initial concentrations. Initial concentrations of 1,000 to 10,000 ug/l were used to develop these degradation rates.

At lower concentrations, the degradation rates depend on effective distribution of microbes for cell to contaminant contact. Secondly, desorption of petroleum constituents from submerged soil may cause rebound and suggest lower degradation rates. For these reasons we cannot calculate a degradation rate for petroleum at low concentrations.

Chromium-Contaminated Ground Water Bioremediation

/in , /by

A bench-scale study demonstrated the viability of bioremediation of chromium contaminated ground water. The key factor to successful bioremediation was the selection of chromium-tolerant microbes. Actual contaminated ground water samples for the test. The ground water contained total chromium of 280 mg/L, with 270 mg/L hexavalent chromium.

The original sample was split into four bottles, with one preserved as a standard. Three split samples were treated with different blends of microbes. All three of the treated samples showed a reduction in the total dissolved chromium and nearly complete conversion from hexavalent to trivalent chromium. The average total chromium concentration in the treated samples was 160 mg/L and the hexavalent chromium concentration was 0.017 mg/L in two of the three treated samples. The sediments were not isolated for testing due to the small volume of sediment in the sample bottles.

Vials Showing Chromium Bioremediation Results

The photograph shows the untreated chromium-contaminated water on the left. The three bottles to the right were treated with various microbial blends.