02/19/2014 § 5 Comments
By: Nadia Lovko, Sustainability Metrics and Reporting Intern
Bioremediation is the use of microbes and biological processes to clean up contamination. Some microbes can eat and process contaminants and use them for fuel. If soils and groundwaters do not have enough of these microbes, they can be added through a process known as bioaugmentation. This process is becoming increasingly popular as a method of cleaning up oil spills. pesticides, and other contaminants.
How does it work?
Bioremediation works by having microbes digest the contaminants, usually releasing small amounts of water and carbon dioxide in their place. For bioremediation to be effective, there must be ideal conditions. This means the right temperature, nutrients, and food must be present. Without these conditions, the microbes will either die or grow too slowly to effectively clean up contaminants. To augment conditions, “amendments” can be added to the soil. These can be household products or air and chemicals. If the conditions cannot be augmented in situ, for example in cold environments, the temperatures cannot be raised, the soil can be dug up and treated ex situ.
How long does it take?
The truth is, it depends. There is no set amount of time for these clean-ups, because not all contamination is the same. The factors that influence the amount of time needed for bioremediation are:
- concentration of contaminants
- accessibility to contaminants
- size of contaminated area
- soil conditions (whether they must be augmented)
- ex situ or in situ treatment
Why use it?
Since bioremediation relies on microbes that already exist naturally, there is no harm to people. The microbes added to an area are expected to die off once the contamination is removed and the food source has dwindled. The chemicals added to the soils to augment conditions are thought to harmless, as they are chemicals used in lawn care and gardening. Samples of soil and groundwater are tested regularly to see the progress and to ensure the safety.
It is also much lower impact than most methods. It is a lost cost, low effort way to clean up contamination without adding more chemicals.
Does it work?
Yes. Bioremediation has been used in cleaning up over 100 Superfund sites. Naturally occurring microbes in the Gulf of Mexico have helped decrease the amount of damage caused by the BP oil spill. Without these microbes in place, the Gulf would undoubtedly be much worse off than it is. Mycelium in mushroom has been used to clean up waterways. Mycelium can break down oil, pesticides, and harmful bacteria, while acting as a natural pesticide.
To find out more about bioremediation, visit the EPA fact sheet.