Utilizing microbes, bioremediation can clean up contaminated soil and groundwater while limiting impacts on the environment, citizens and animals. During the bioremediation process certain microbes are used to “devour” contaminants, including oil and other petroleum products, solvents and pesticides. However, they can eat long-chain linear aliphatics, e.g., grease, cooking oils, petroleum hydrocarbons; nutrients, e.g., ammonia/nitrogen; short-chain aliphatics, e.g, hexane, octane; branched aliphatics, e.g., isoprenols; chlorosubstituted aliphatics, e.g, chlorobutadiene; aromatics, e.g., benzene, phenols, naphthalene, toluene; and chlorosubstituted aromatics, e.g. 2, 4, D, chlorotoluene, mono- and disubstitute chlorophenols and chlortoluenes.
With their diverse appetites, microbes offer the ability for municipalities to complete different cleanups or look toward creating legislature addressing unwanted products in wastewater that threaten to gum up the works.
“Of course,” said Director of Marketing Sean Griffin with Osprey Biotechnics Inc., “different genus of bacteria like different things.
“One type might like (one contaminant) — another strain might not have it on their diet or require additional additives that could be harmful to the environment,” he said.
Griffin noted beneficial bacteria can be introduced to areas affected by toxic waste — like petroleum — to begin the cleanup process and provide a natural solution.
According to the Environmental Protection Agency, other important elements are needed for bioremediation to be effective: Namely, the right temperature, nutrients, and food source must be present. To achieve these proper conditions, amendments may be added; they can range from household items like molasses and vegetable oil to air and chemicals that produce oxygen. An EPA guide notes, “Amendments are often pumped underground through wells to treat soil and groundwater in situ (in place).” These amendments stimulate the natural bacteria, but cannot increase the population as much as bioaugmentation. In some locations the climate and soil density may prevent bioremediation from being effective in situ.
Osprey Biotechnics provided an example where bioremediation using their product was completed in the area where there was an old dry cleaning shop. Solvents had found their way into the ground from the shop’s past operations. By using the right microbes, the solvents were targeted and devoured in a green manner. Griffin stated, “Our beneficial microbes remove the toxins and release only carbon dioxide and water. The naturally occurring bacteria return to the environment. This is why our product is recognized by the EPA’s Design for the Environment criteria.”
The EPA plays a vital role and works with companies to create environmentally safe microbes that meet the EPA’s Design for the Environment challenge. The product is then recognized as an environmentally preferred product that performs well and is safer for human health and the environment.
Spills of industrial solvents and petroleum may be infrequent on municipal properties, however, they could potentially happen on neighboring or adjacent properties, or in prior use of municipal properties. Bioremediation offers solutions for dealing with properties that now have historical or recently contaminated soil, groundwater.
“It is a quick and safe approach,” Vice President Mike Saul of CL Solutions LLC, a distributor for Osprey Biotechnics’ products that also provides technical support, said.
Due to their nature, microbes can be used in sensitive locations such as in or near protected bogs or swamps, surface water or water supply groundwater. Saul stated microbes can be sprayed on top of still waters, and as long as the microbes are in contact with the contaminants, they will get to work. However, he cautioned, they may not be appropriate for contaminated flowing waters. “You want them in contact with the contamination,” he said. This is hard to achieve with rivers, streams and larger bodies of flowing water like the ocean, where the microbes may be dispersed in uncontaminated water. However, for municipalities with canals on their properties there are options.
“In some situations, booms can be placed to contain the (contaminated) water, which provides a stable treatment area.”
If contaminants make their way into the soil, drill rigs can be brought in to probe the ground and inject the microbes to into the contamination is. Once microbes are in contact with contaminants, Saul said the process should take days or weeks to clean up rather than years. This approach is particularly helpful when it comes to meeting development or construction deadlines in areas undergoing redevelopment. “In situ treatment can be done during construction,” he said, which doesn’t slow down that redevelopment.