Bioremediation | Using Microorganisms to Cleanup Toxic Waste
Bioremediation | Using Microorganisms to Cleanup Toxic Waste
Cleaning up toxic waste using bioremediation is not the newest technique used to perform environmental remediation, but it is certainly one of the more interesting and effective ways to cleanup toxic waste. In a nutshell, bioremediation involves the injection of microbes and/or nutrients into polluted soils and ground water to accelerate the cleanup of toxic waste. The cleanup occurs as the microbes feed off of and digest toxic waste, breaking it down into benign constituents. Cleanups of toxic waste sites can be performed rapidly, if bioremediation is implemented correctly and the microbes perform as expected.
The United States has embarked on a multi-generational mission to cleanup (remediate) polluted properties throughout the country, including the well known Superfund program that addresses the most severely polluted sites, to protect the environment and bring the properties back to productive uses. This effort has proven to be very expensive and time consuming. The necessity of cheaper and faster site remediation methods has led to many cost and time saving innovations in the field of environmental site remediation, including bioremediation, which has grown more popular over the years as it has proven that it works in real world toxic site cleanups.
Bioremediation also has the added benefit of being a non-invasive way of cleaning up toxic waste. There is no need for digging dirt out from an entire site or spending decades pumping and treading ground water. Bioremediation can be performed with relative obscurity, with little disruption to a property beyond drilling wells to inject microbes and/or nutrients.
Bioremediation | Using Microorganisms to Cleanup Toxic Waste | Methods
Traditionally, the most common remediation method utilized to bring ground water contaminants beneath polluted properties to safe levels below regulatory thresholds has been a ground water treatment system (aka pump and treat). While often effective in the long run, running a ground water treatment system, which involves pumping ground water to the surface for treatment, is costly and time consuming. Periodic changeouts of filters, system maintenance, electrical costs, and ground water monitoring, all drive up the cost of running a ground water treatment system.
Looking for a cheaper and faster way to treat ground water contamination, environmental scientists noticed that some sites that had high levels of naturally occurring microorganisms in the ground water responded more quickly to remediation efforts. Further investigation revealed that certain naturally occurring microorganisms would literally eat and digest organic toxic contaminants, and in the process of digesting them break the toxic contaminants down to their benign constituent elements or compounds. Organic toxic contaminants that are treatable via bioremediation include petroleum byproducts, such as gasoline and heating oil, and dry cleaning chemicals, such as tetrachloroethylene (PCE) and trichloroethylene (TCE), which are common pollutants found on polluted sites.
With this knowledge in hand, a whole new remediation industry was born, which has come to be known broadly as bioremediation. Under the umbrella of bioremediation, there are a number of on-site (in-situ) and off-site (ex-situ) bioremediation methods.
One common in-situ method of bioremediation, called biostimulation, involves the stimulation of existing naturally occurring microorganisms beneath a site via the injection of nutrients, such as fertilizers, or food sweeteners, such as molasses into ground water. If done correctly, the injection will cause the naturally occurring microorganisms to multiple rapidly beneath the site, thus greatly enhancing the naturally occurring breakdown of toxic contaminants in ground water.
Another common in-situ method of bioremediation, called bioaugmentation, involves the injection of select or engineered microorganisms into ground water beneath a site; which are selected based on site conditions and the type of ground water contamination that is targeted for treatment. The injection introduces a large number of engineered microorganisms into ground water beneath the site, which then ingest and breakdown the toxic contaminants in ground water. Biostimulation is sometimes used in conjunction with bioaugmentation to enhance the effectiveness of bioaugmentation.
Organic toxic contaminants in soil are also reduced when bioremediation methods are employed against ground water contamination. This is because the microorganisms do not remain exclusively in ground water, and migrate to the soil above; digesting and breaking down the toxic contaminants in soil in the process. Reducing soil contamination can reduce or eliminate the need for costly off-site soil disposal at polluted sites.
While not viable on all contaminated sites, such as sites with poor sub-surface water flow conditions or sites with inorganic contaminants such as heavy metals, bioremediation has proven to be highly effective at reducing toxic organic contaminants to safe levels below regulatory thresholds at thousands of sites across the United States. The effectiveness of bioremediation is measured by the collection of post-treatment soil and ground water samples. Site remediation can now be achieved via bioremediation in a fraction of the time that it once took via the traditional ground water treatment system method, thus saving a great deal of time and money, and allowing contaminated sites to be returned to productive uses or to be redeveloped.
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How Bioremediaton Works
John Coviello (author) from New Jersey on November 22, 2019:
I'm glad you found this article about bioremediation to be so useful and helpful Kenny. It's a great way to remediate contaminated sites without creating disruption to what's going on above ground.
Kenny on November 19, 2019:
This is an outstanding article. I was searching for a simplistic way to explain bioremediation and your article is a great help.
John Coviello (author) from New Jersey on March 28, 2016:
I'm glad you found this Hub to be informative and interesting. Actually, there's nothing to worry about bioremedial microogranisms going awry. They are naturally occoring microogranisms. Bioremediation just introduces them to subsurface environments where they either exist in too small of numbers to be effective or do not exist. They just do their thing and run their course.
Bill from Greensburg Pennsylvania on December 30, 2014:
I found this to be an informative and interesting idea. The only fear would be is that whatever is introduced to remove those toxins is not something that down the road someones says oh my we should not of put that in our soil. great article.