Remediation, the process by which contamination is removed from soils and water, can be confusing to both environmentalists and non-environmentalists. Even more complicated is a subset of remediation – Bioremediation. This obscurity is exasperated by the fact that all forms of bioremediation include the use of living organisms (biological microbes) to remove or reduce harmful pollutants in contaminated areas.
However, the devil is in the details. While some bioremediation techniques simply stimulate naturally occurring organisms to eat up toxic chemicals and pathogens, other techniques introduce microorganisms into the environment to achieve remedial goals. At the end of either process, the elevated populations level off when their energy source is gone and nature eventually restores its balance (homeostasis).
In essence, there are only two types of bioremediation techniques: biostimulation and bioaugmentation. These should not be contrasted with the two main methods of soil remediation (in-situ/ex-situ) which refers to how a remediation treatment is carried out and not the actual Biology (introduced or existing). To complicate things further, there are two subsets of microbiology under which oxygen can successfully aid or harm the process (aerobic and anaerobic).
Side note: bioremediation techniques are not the only confusing terms in environmental science. For instance, ‘in-situ’ and ex-situ’ are also misinterpreted to mean on-site and off-site, when using the term in situ or ex situ in remediation, the literal meaning is with or without excavation.
Biostimulation:
Biostimulation techniques motivate natural (indigenous) organisms to consume soil/water pollutants. Ordinarily, the naturally occurring microorganisms put in place by mother nature could take decades to degrade contaminants but by modifying the environment through the addition of nutrients, this time can be reduced. These nutrients and/or electron acceptors include phosphorus, nitrogen, oxygen or carbon.
Examples of biostimulation techniques are biosparging and bioventing. Bioventing is the injection of high-pressure air (oxygen) into the soil or unsaturated vadose zone to enhance aerobic biodegradation. Biosparging is the injection of air into the saturated zone of the soil matrix or groundwater table to stimulate degradation.
Bioaugmentation:
Bioaugmentation is the addition of actively growing (exogenous) microbial strains to supplement the degradation capacity of indigenous microbial populations. Usually, site assessments would have been conducted to determine the chemical structure and concentration of contaminants, the size and nature of existing microbial populations and the nature of the physical environment (soil type, pH, porosity, hydraulic conductivity, etc) before the right bioaugmentation technique can be conducted.
It is also worth noting that because of the introduction of external elements, an effective bioaugmentation technology must be able to maintain genetic stability and viability during storage, survive in foreign and hostile environments, effectively compete with indigenous microorganisms, and move through the pores of the sediment to the contaminants.
In most cases, nutrient application alone will not produce the desired remediation results. However, augmenting contaminated soils with the planet’s most aggressive bacteria will often produce desired results in as little as 30 days. In summary, while both techniques have an application in the remediation industry bioaugmentation reduces the risk and uncertainty that have often been associated with biostimulation. Since its inception in 2014, Delta Remediation, has grown to become a worldwide leader in the area of bioremediation. Through its proprietary remediation technology (BioLogix) and additional innovative solutions (ScreenLogix Rapid TPH Test), Delta Remediation is proud to provide industry leading bioremediation solutions to meet your site’s needs.
Get in touch with our team at [email protected] or 780-962-7991.
