Bioremediation Flashcards
what is bioremediation
the utilisation of microorganisms to transform contaminants into a benign and/or less mobile form
what could the remediation goals be?
to remove, degrade, or immobilise the contaminant
what are the 3 strategies
- stimulate natural microbial community
- add surfactants or other substances
- add microorganims
what are the options for stimulating natural microbial community
- Aeration (increasing oxygen)
- Adding nutrients (N, P, Fe…)
- Adding PEDs or TEAs
finish the sentence:
add surfactants or other substances to…
enhance microbial attachment or dispersion
finish the sentence:
add microorganims that are…
specifically selected or bred/engineered, “bioaugmentation”
what is an insitu bioremediation technique
permeable reactive barrier - can include microorganisms or not and used for organic or inorganic contaminants
what are the 5 ex situ methods
- slurry bioreactors
- constructed wetlands
- composting
- pump and treat
- biopiles
ORGANIC CONTAMINANTS: what is the goal
degrade the organic contaminant (oxidise it)
ORGANIC CONTAMINANTS: what can be used to achieve this
- petroleum hydrocarbons
- chlorinated hydrocarbons
- plasticisers
- solvents
ORGANIC CONTAMINANTS: how does aeration work
organic contaminants are served as PED for chemoheterotrophy
organic contaminants are degraded (oxidised) fastest via aerobic respiration)
ORGANIC CONTAMINANTS: when aeration is no sufficient or feasible what can be used
stimulating the anaerobic chemoheterotrophs that can degrade the pollutants
ORGANIC CONTAMINANTS: what can be the problem with stimulating anaerobic chemoheterotrophs
can be slow, issues with toxisity, dispersion and so may need to add nutrients and electron shuttles to help it along
ORGANIC CONTAMINANTS: what can be added to help microorganisms stick to contaminants
use surfactants or other substances to be added in order to enhance the microbial attachment or dispersion
METALS AS CONTAMINANTS: what are the natural sources of metals
rocks and minerals
METALS AS CONTAMINANTS: what are the anthropogenic sources of metal contamination
agriculture, metallurgy, energy production, microelectronics, mining, sewage, waste disposal
METALS AS CONTAMINANTS: what supplies lots of metals to plants and soils
atmospheric depostion
METALS AS CONTAMINANTS: what is one of the main sinks in terrestrial ecosystems
soils
METALS AS CONTAMINANTS: what is a major sink in aquatic ecosystems
sediments
METALS AS CONTAMINANTS: what are mobility and toxicity dependant upon
concentration and speciation (especially oxidation state)
METALS AS CONTAMINANTS: what is a global metal contaminant
Uranium
METALS AS CONTAMINANTS: what is a focus of the remediation at most nuclear sites
to prevent uncontrolled dispersion and transport in groundwater
METALS AS CONTAMINANTS: what is more mobile U(4) or U(6) and why
U(6) - the oxidised form is more mobile because it in an aqueous cation
whereas
U(4) - the reduced form has low solubilty and therefore is less mobile
METALS AS CONTAMINANTS: what are the 4 potential strategies to prevent dispersion of Uranium
- Bioreduction
- Biosorption
- Bioaccumulation
- Biomineralisation
METALS AS CONTAMINANTS: what does bioreduction include
adding electron donors
METALS AS CONTAMINANTS: what does biosorption do
passive sorption of U onto cell surfaces
METALS AS CONTAMINANTS: what does bioaccumulation do
cells uptake contaminant
METALS AS CONTAMINANTS: what does biomineralisation do
induces precipitation of mineral
