Glossary

Cleaning soil and groundwater contaminated with oil or VOCs by using the natural ability of microbes to break the contaminant down into water and carbon dioxide. Unlike excavation and disposal, it produces no bulk waste.

Related page: What is bioremediation?

Adding microbes with strong degrading ability to the contaminated site. BioRangers mainly uses this approach, with microbial consortia such as the Oppenheimer Formula.

Related page: How bioaugmentation works

Activating the microbes already living at the site with nutrients and oxygen so they degrade the contaminant. Because no microbes are added, it can take longer to get going.

Related page: The two approaches compared

A product containing several oil-degrading microbial species at high concentration. The microbes are taken from natural environments and are not genetically modified. BioRangers chooses between the Oppenheimer Formula, TerraZyme, ZeoBio and others to suit site conditions.

Related page: Microbial products

Treating contaminated soil or groundwater where it lies, without excavating or pumping it out. Often possible under buildings and at operating plants. Its counterparts are on-site (excavated and treated within the site) and off-site (hauled away).

Related page: Treatment methods

The hydrocarbons that make up gasoline, kerosene, diesel, heavy oil and lubricating oil. TPH (Total Petroleum Hydrocarbons) is their combined concentration and the usual measure of how contaminated soil is.

Related page: About oil

The signs of oil contamination people notice directly: soil that smells of oil, or a film floating on groundwater or puddles. Japan's oil-contamination guideline takes this nuisance to living conditions as the starting point for action.

Related page: How Japan approaches oil contamination

Benzene, toluene, ethylbenzene and xylene: volatile components abundant in gasoline. Benzene is a designated hazardous substance under Japan's Soil Contamination Countermeasures Act and is a common issue at former gas stations.

Related page: What oil is made of

Compounds built from several linked benzene rings, common in heavy oil and tar and slow to degrade. Our article series includes degradation test results with the microbial consortium.

Related page: PAH degradation tests (Article Vol. 5)

Organic compounds that evaporate readily at room temperature. In soil and groundwater contamination the term usually means chlorinated solvents such as trichloroethylene. BioRangers treats VOCs as well as oil.

Related page: VOC remediation

Chlorinated solvents long used for degreasing metal parts and dry cleaning. Heavier than water, they sink deep underground. Degradation passes through intermediates such as dichloroethene, whose concentrations must be tracked too.

Related page: Chlorinated ethene degradation

Excavated soil is spread out in a designated area, sprayed with a solution of microbial product and nutrients, and turned. The most frequent method in our track record.

Related page: Landfarming

An intensified form of landfarming: treated soil is heaped up and air is blown through pipes buried inside to speed degradation. Suits sites with limited space.

Related page: Biopile

Solution is sprayed onto relatively shallow contaminated soil, which is then mixed in place with an excavator. No digging out or hauling.

Related page: In-situ mixing

Microbial product and nutrients are injected underground through boreholes (direct) or wells. No excavation; often feasible under buildings and at operating facilities.

Related page: In-situ injection

BioRangers' patented system in which contaminated groundwater or wastewater contacts the microbes inside a tank so the oil is degraded. Used when groundwater is pumped up for treatment and for factory wastewater.

Related page: Bioreactor

A laboratory test on soil or groundwater from the actual site to confirm that the microbes can degrade that contamination. Always carried out before the remediation plan; the basis for method, quantities and schedule.

Related page: Testing & monitoring

Sampling and analysing soil or groundwater at intervals during the works to evaluate contaminant concentration, microbial counts and nutrients. Product, nutrients, moisture and oxygen are adjusted accordingly until the target is confirmed.

Related page: How monitoring works

Materials that supply the nitrogen (N) and phosphorus (P) microbes need to degrade oil. Oil is rich in carbon (C), so balancing carbon, nitrogen and phosphorus helps degradation proceed.

Related page: Nutrients and trace elements

Agents that emulsify and disperse oil so microbes can reach it. BioRangers uses highly biodegradable plant- and microbe-derived surfactants. Dispersants poured onto soil can spread the oil, so they must be used with care.

Related page: Surfactants

Digging out contaminated soil, hauling it off site and treating it at a disposal facility. Fast and certain, but costly, waste-heavy and hard to do under buildings or at operating plants. Bioremediation is its alternative or complement.

Related page: Compared with other methods

The Ministry of the Environment's 2006 framework for responding to oil-contaminated soil. It starts from nuisance to living conditions such as odour and film, chooses measures according to land use, and uses TPH as a reference when setting targets.

Related page: Japan and other countries