how bioremediation works
bioremediation relies on stimulating the growth of certain microbes that utilize contaminants including oil solvents and pesticides for sources of food and energy these microbes convert contaminants into small amounts of water as well as harmless gases such as carbon dioxide bioremediation requires a combination of the right temperature nutrients and foods the absence of these elements can prolong the cleanup of contaminants conditions that are unfavorable for bioremediation can be improved by adding amendments to the environment such as molasses vegetable oil or simple air these amendments optimize conditions for microbes to flourish accelerating the completion of the bioremediation process bioremediation can be done in situ at the site of the contamination or ex situ at a location away from the site ex situ bioremediation may be necessary if the climate is too cold to sustain microbe activity or if the soil is too dense for nutrients to distribute evenly ex situ bioremediation can require excavation and cleaning of the soil above ground and this can add significant costs to the process the bioremediation process can take anywhere from several months to several years to complete depending on variables such as the size of the contaminated area the concentration of contaminants temperature soil density and whether bioremediation will occur in situ or ex situ advantages of bioremediationbioremediation offers numerous advantages over other cleanup methods it minimizes damage to ecosystems by relying solely on natural processes bioremediation often takes place underground where amendments and microbes can be pumped to clean up contaminants in groundwater and soil bioremediation doesn t disrupt nearby communities as much as other cleanup methodologies as a result the bioremediation process creates relatively few harmful byproducts mainly because contaminants and pollutants are converted into water and harmless gases like carbon dioxide it s cheaper than most cleanup methods because it doesn t require substantial equipment or labor example of bioremediationthe exxon valdez oil tanker ran aground off the coast of alaska in 1989 and ended up spilling approximately 11 million gallons of oil bioremediation was gaining traction as a viable option for oil cleanups at around this time the epa and exxon mobil corporation xom both began testing compounds initial tests regarding the effectiveness of bioremediation looked promising 1more than 100 000 pounds of fertilizer were applied over more than 2 000 applications to the affected areas between 1989 and 1990 the cleanup was considered complete by mid 1992 and the fertilizer had degraded nearly all the oil compounds 2