Bio-remediation and Phyto-remediation Flashcards
What is bioremediation?
Is a process that uses living or dead biological systems to remove environmental pollutants from the air, water, soil and other environments. It’s a technique that enhances the natural biodegradation processes that occur over time
What is phytoremediation?
It is a cost effective environmental restoration technique that uses plants to clean up contaminated soil, water and sediment
Plants absorb contaminants through their roots and then store convert or release them in various ways
What is biodegradation?
Refers to the partial, and sometimes total, transformation or detoxification of contaminants by microorganisms
What are the steps of phytoremediation?
Phytofiltration- uses plants to clean water systems
Phytostabilization- plants that stabilize toxic materials within the soils
Phytovolatilization- occurs when plants extract metals and release them into the air
Phytoextraction- where metals are translocated and accumulated in harvestable shoots and incinerated
Phytodegradation- plants use their metabolism to break down pollutants to non-pollutant compounds
Rhizosphere degradation- breakdown of metals by rhizospheric microorganisms
What is an example of phytoremediation?
Plants extract heavy metals from water and soil bioaccumulating them in various parts (root, stem, leaves, flowers, fruit), without adverse effects on soil structure, fertility and biological activity
In addition, phytoremediation has the advantage to be driven by solar energy and also the potential to remove pollutants from the contaminated sites almost completely
What plants are used in phytoremediation?
Hyperaccumulators are plants capable of absorbing and storing exceptionally high concentrations of heavy metals and other pollutants in their tissues without suffering toxic effects.
What is an example of a hyperaccumulator?
Duckweed: an efficient hyperaccumulator of heavy metals in water bodies
What are the strategies for improving phytoremediation efficiency of duckweeds?
Genetic engineering
Overexpression of potential HM resistant/tolerant genes
Selection of transformants on antibiotic selection media
What are the advantages of Phytoremediation?
It is beneficial as it can be applied on large areas of land, requires minimal monitoring and the accumulated metals in biomass can be recovered, especially in the case of critical metals
Properties of the soils are improved, the microflora from the rhizosphere area is restored
Phytoremediation is based on an autotrophic system, for which the nutrient intake is relatively reasonable, easy to manage
Socially acceptable due to it’s aesthetic appearance and environmental sustainability
How are oil spills cleaned up?
Booms (floating barriers)- the very first action after an oil spill is directed to the oil collection, preventing it from spreading
Skimmers are boats and other devices remove oil from the sea surface
In-situ burning. Used in the early stages of an oil spill, before its weathering and evaporation of toxic volatile components
Largely decreases the costs of the listed activities
What are dispersants?
Surfactants (or detergents). They contain both hydrophobic and hydrophillic moieties. The hydrophobic moeity is orientated towards the oil, while the hydrophillic head is turned toward the water. This leads to the significant reduction of the interfacial surface tension of oil droplets, thus increasing availability of the oil to hydrocarbon-degrading microorganisms
What is essential to the effective biodegradation of hydrophobic hydrocarbon substrates?
Bacterial surface properties are essential to the effective biodegradation of hydrophobic hydrocarbon substrates
How can bacteria be used to deal with oil spills?
Fimbriae or flagellum of bacteria attach to petroleum oil
Biosurfactants secreted by bacteria emulsify petroleum oil
Proteins, lipids, and other small molecules on bacterial surface for adhering petroleum oil
What is more effective aerobic or anerobic bioremediation?
Aerobic bioremediation is usually preferred because it degrades pollutants 10 to 100 times faster than anaerobic bioremediation
Facultative types can thrive under either aerobic and anaerobic conditions. Certain bacteria bacteria beloging to the Bacillus and Pseudomonas species have these desirable characteristics
What is crude oil?
Crude oil is a mixture
Hydrocarbons of different lengths
A compound made from hydrogen and carbon
