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Transcript of Bioremediation
• These organisms are heterotrophic, which means they eat from other food sources other than itself (in some cases, they can be autotrophic to some degree like protists). These microorganisms include many bacteria (bacterial bioremediation) and fungi (mycoremediation).
• Not all organisms are able to digest and eliminate the pollutant, especially if it’s in high concentration. However, some will adapt and evolve to be able to remove highly contaminated soils. These remaining microorganisms can withstand a lot. Deinococcus radiodurans has at least 4 spare sets of genes that allows itself to repair DNA after radiation. Examples of Microorganisms
• This is a strand of bacteria that can consume paint thinners and petroleum refining agents; most synthetic products
• Researchers are highly interested in this bacterium because it is the most capable bacteria known to digest aromatic or aliphatic hydrocarbons- these are products of burning fossil fuels or ultimately organic matter.
• Highly able to withstand environmental stress
• Uses other organisms to its advantage. For instance, “Fungi Saccharomyces cerevisiae [produces] the necessary glucose and also [maintaines] the pH,” to the Pseudomonas Putida's advantage. Pseudomonas Putida Phanerochaete chrysosporium • A type of rot fungus that can break down aromatic polymer lignin. This is the outer lining of a series of hydrocarbons, “containing one or more benzene rings.” Product of burned organic material.
• Also able to break down various pesticides, PCBs (an ingredient of manufacturing materials like refining oil) and poisons due to its production of extracellular enzymes (proteins that work outside the cell). Nitrosomonas europaea:
oxidizes ammonia to nitrate Nitrobacter hamburgensis:
Nitrogen oxidization into nitrate Paracoccus denitrificans: “Nitrate into Nitrogen gas” known as denitrification Chemical Reactions Involved in Bioremediation • A microorganism or microbe will break down an organic contaminate
o These include Petroleum by-products, Polychlorinated Biphenyls (PCBs), Polycyclic aromatic compounds (PAHs), etc. • The contaminate will contain carbon –essential for production of cell mass- and electrons- a source of energy for cell reproduction • After the contaminate is oxidized, the electrons are then separated for different purposes (the contaminate serving its purpose as an electron donor) • Some electrons go to an electron acceptor for energy –these are an element or compound that “accepts” electrons like iron, nitrate, sulfate and most commonly oxygen.
o The electrons stabilize the element or compound reducing its abundance.
o Also, the energy from the newly formed anion is transferred and used to produce the new cell.
o This process is known as aerobic (oxygen) or anaerobic (other electron acceptors) respiration • The rest of the electrons and carbon is used, using the energy gained from the respiration, to form a new cell. "Bio" means life or organisms
"Remediate" means to solve a problem
The literal definition of Bioremediation is to solve a problem using living organisms • From previous knowledge we know that certain organisms help their ecosystems by breaking down organic compounds.
• Bioremediation takes these pollution eating organisms and places them in organic compound polluted areas and promoting their rapid growth, to 'clean up' the environment. How it Works In some sites, proper microbe growing conditions are not present.
EPA digs up the soil on pad or in tanks.
Often times mixing soils will evaporate the contaminants.
To prevent the vapors from escaping, they are trapped in special tanks.
Then they are treated in the tanks.
To clean up contaminated water; wells are dug up and microbes and amendments are added.
In some cases a bioreactor is attached, generally a large tank where the water is mixed with microbes and amendments to clean it.
Depending on the condition of the site, the cleaned water may be placed back or released onto the surrounding ground. Pros and Cons Pros: -Inexpensive and long-lasting
-No buildings need to be dug up and removed
-The method is quick above ground and slower underground (where the water moves more slowly)
-As long as there is toxic waste the bacteria continues to feed on it and will eventually clean up the entire site
-This method has been proven effective in previous oil spills
-Does not require the use of technology Cons: -It's difficult to control where the bacteria goes
-Ethical concerns about having lots of germs spread around
-Some people are concerned that some of the germs may be able to kill people or make them sick
-However, most bacteria that eat toxic waste are not able to make people sick
-Many people are concerned with the use of genetically modified bacteria for toxic cleanup, since it's not natural
-Developing a consortium of compatible bacteria strains requires a lot of time and effort ffects on Communities -In 1979, a pipeline carrying crude oil burst and contaminated the underlying aquifer
-USGS scientists studying the site found that toxic chemicals leaching from the crude oil were rapidly degraded by natural microbial populations
-Over time the contaminated ground water stopped enlarging as rates of microbial degradation came into balance with rates of contaminant leaching
-First example of bioremediation without human intervention By: Aisha, Sama, Sarah Jane,Yashvi Different Form of Bioremediation
Concept of taking living organisms to clean the environment. Phytoremediation
•Phytostabilization: immobilizing metals with the use of plant roots (absorption in the soil, and transpiration) and leaves (catching contaminated dust)
•Phytoextraction: “extracting” contaminates by purposely planting plants to absorb pollutants above ground, preventing runoff. -In 1975, a massive leak from a military fuel storage facility in South Carolina released 80,000 gallons of kerosine-based jet fuel
-The fuel began to soak into the soil and reached the underlying water table
-By 1985, the contamination had reached the residential area
-In 1992, nutrients were delivered to contaminated soils through infiltration galleries
-By 1993 the contamination had been reduced by 75% -Remediation is an all natural process, (hardly produces toxic by-products)
-Bioremediation is not a good option in order to clean up large oil spills
o This is a fairly slow process(The longer the oil stays in the water the more toxic and
dangerous it gets)
-Takes longer then another physical or chemical technique.
-Gasoline Studies have shown rapid microbial degradation of gasoline contaminants and have
shown the importance of processes in degrading contaminants.