The  Terms and Definitions Remediation

Application of a process or technology to a mixture of materials such that the problem or hazard associated with the mixture is counteracted or removed. There are two types of remediation:

• Chemical or biochemical reactions like oxidation or reduction of the chemical components through a chemical or biological activity.

• Physical separation takes a combination of chemical species and by applying physical or chemical principles, creates two or more separate products which differ in composition.
  

Bioremediation

The use of microorganisms or microbial processes to detoxify and degrade environmental contaminants.

Bioremediation uses naturally occurring microorganisms to degrade and break down hazardous substances into less toxic or non toxic substances. Microorganisms, just like humans, eat and digest organic substances for nutrients and energy. Certain microorganisms can digest organic substances that are hazardous to humans.

The organic contaminants degrade in harmless products consisting mainly of carbon dioxide and water. Some examples of organic contaminants include fuels, such as oil spills and solvents.

Many names and terms are applied to Bioremediation systems for the treatment of soils. Soil treatment systems will be divided into three mayor categories: Land treatment, including landfarms and prepared bed systems; In-Situ sub-surface, including dissimulation via bioventing; Bioreactor systems.

Bioremediation has been used at more than 150 locations to cost effectively remediation hundreds of thousands of cubic yards of contaminated soil. Various superfund sites have been completely and successfully remediated using biological treatment.

Some of the most cost effective bioremediation techniques are:

• In-Situ - Bioventing

• Ex-Situ - Biopiles

• Ex-Situ Landfarming or soil treatment

• In-Situ Natural Attenuation

Responsible parties have saved more than 300 million dollars by implementing bioremediation programs.

Why Bioremediation?

In-Situ Bioventing

Is the process of aerating soils to stimulate in situ biological activity and promote bioremediation. The technique injects oxygen into the contaminated soil at a low rate to encourage biodegradation rather than volatilization.

This technique is able to treat large volumes of soil effectively and with minimal disruption to business operations. It can also remove contamination from near or under fixed structures. Bioventing also reduces the need for aboveground treatment because it works to degrade contaminants in place.

Bioventing has been implemented at more than 150 sites and has emerged as one of the most cost effective and efficient technologies currently available for vadose zone remediation of petroleum contaminated sites.

Ex-Situ Biopiles

Is a technique for removing contaminants from excavated mounds or “piles” of soil. Nutrients are added to the soil mounds, which are often several feet high, to facilitate bioremediation. Aeration conduits and irrigation systems are constructed in the mound.

This low-maintenance technique requires a relatively short treatment time and also provides better control over aeration, moisture, nutrient levels, and soil texture than other methods.

Biopiles have been effective in reducing concentrations of nearly all contaminants below regulatory limits and is most appropriate for shallow contamination sites that cover a large horizontal area.

Ex-Situ Landfarming

Also known as “land treatment” is a technique for removing contaminants from excavated soil by adding nutrients and spreading the soil in layers over a lined treatment area.

The contaminated soil is periodically tilled to facilitate the natural release of volatile organic compounds (VOC’s) and the biodegradation of contaminants.

Landfarming has been proven effective in reducing concentrations to below regulatory limits on many soil types and nearly all types of contaminants.

In-Situ Natural Attenuation

Also known as passive bioremediation is an approach that depends upon natural processes to degrade and dissipate contaminants in soil and groundwater.

This method of remediation relies on microorganisms to break down petroleum products in the soil. It does not require the addition of oxygen or nutrients to facilitate the process.

In-Situ Natural Attenuation is extremely slow. It is most appropriate when expedient remediation is not needed and nearby receptors will not be affected. To date, few sites have been fully remediated using this approach.