S10-S12 Flashcards
What is biodegradation?
Biodegradation is the digestion or breakdown of any complex compounds into simpler molecules with the help of living organisms that occurs naturally.
What is bioremediation?
Bioremediation is a process of degradation of environmental contaminants by microbial consortia via a man-made engineered execution plan to get the desired product.
Biodegradation VS Bioremediation
Principle
1: It solely depends on the metabolic capabilities of the microorganisms to progressively convert hazardous contaminants to soluble and stable compounds.
2: Based on the degradative capabilities of microbes but also on the factors such as temperature, nutrient supplements, aeration, and more, controlled by humans that help in enhancing the remediation process
Type of Process
1: Self-paced, naturally occurring process.
2: An artificially engineered remediation process employing microorganisms.
Time
1: It is a slow-paced process since it requires time to transform contaminants into water and carbon dioxide completely.
2: Fast-paced process dealing with the transformation of pollutants into a stable form.
Human Intervention
1: Human intervention is not required, as it is a natural process
2: Experts and Scientists carefully design the execution plan to monitor and analyze in order to get the desired result
Bioremediation CRITERIA
- Microorganisms must have the needed catabolic activity (i.e., capacity to degrade organic matter.)
- Those organisms must have the capacity to transform the compound at reasonable rates and bring its concentration to levels that meet regulatory standards.
- They must not generate products that are toxic at the concentrations likely to be achieved during the remediation.
- The site must not contain concentrations or combinations of chemicals that are markedly inhibitory to the biodegrading species, or means must exist to dilute or otherwise render the inhibitors innocuous.
- The target compound(s) must be available to the microorganisms.
- Conditions at the site or bioreactor must promote microbial growth or activity (e.g., an adequate supply of inorganic nutrients, sufficient O2 or some other electron acceptor, favorable moisture content, suitable temperature, and a source of carbon and energy for growth ) if the pollutant is to be cometabolized.
- The cost of the technology must be lower or, at worst, not higher than that of other technologies which can also destroy the target substance.
Techniques for Soil Bioremediation
- Ex-Situ Bioremediation
Ex-situ means to remove contamination mat to a remote treatment location.
Disadvantage: Poses a hazard to spreading contamination or risking an accidental spill during transport. - In-Situ Bioremediation
Bioremediation process is done at the contamination site defines the in-situ method.
In situ is the preferred bioremediation method, as it requires less mechanical efforts to eliminate spreading contaminants and prevent the spread of pollutant through transportation or pumping away to other treatment locations.
2 Classes of Ex-Situ Bioremediation
- Slurry Phase
This technique involves the process of combining contaminated soil with water and other additives in a large bio-reactor and mixed to keep the indigenous micro-organisms in contact with the contaminants.
Essential nutrients, oxygen are added and the conditions in the bio-reactor are ensured at optimum environment for the micro-organisms to degrade the contaminants. Slurry-phase is a relatively rapid process compared to other biological treatment processes specifically for contaminated clays. - Solid Phase
Solid phase treatment is used to treat soils in above-ground treatment area. This area equipped with collection systems to check the contaminants from escaping the treatment. The parameters like moisture, heat, nutrients, and oxygen are controlled to enhance rate of degradation. Solid-phase systems are simple to process and maintain in spite of, it requires a large amount of space and more time of treatment than slurry-phase processes.
Three Solid Phase Techniques:
Land Farming, Solid Biophiles, and Composting
2 Classes of In-Situ Bioremediation
- Intrinsic Bioremediation
Intrinsic bioremediation is a process for converting environmental pollutants degrades to non-toxic forms through the immanent abilities of naturally occurring microbial population at the site. This process is usually employed in underground places as such underground petroleum tanks. This technique deals with stimulation of indigenous microbial population by feeding them nutrients and oxygen to increase their metabolic activity. - Enhanced (Engineered) Bioremediation
This technique involves the introduction of specific microorganism to the contaminated site. Engineered in situ bioremediation accelerates the degradation process by enhancing the physicochemical conditions to increase the growth of microorganism.
Techniques:
Bio-venting, Bioslurping, Biosparging, Bioaugmentation, Phytoremediation, and Mycoremediation
Advantages and Disadvantages of Microbial Bioremediation
Advantages
1. Public Acceptance
2. Low Cost Technology
3. It can be done in situ and ex situ
Disadvantages
1. Takes relatively long to achieve treatment
2. May not be effective on all contaminants
3. Pollutant and environmental limitations
4. Specialized expertise are required in designing and implementing.
Applications of Microbial Bioremediation
- Wastewater and industrial effluent treatment
- Soil and land treatment
- Control of air pollution
- Solid waste management
Microbial Bioremediation Strategies
- In situ Bioremediation
- Ex situ Bioremediation
- Bioreactors
Microbial Bioreactors in Bioremediation
- Slurry Phase Bioreactors
- Partitioning Bioreactors
- Stirred Tank Bioreactors
- Biofilter Bioreactor
- Airlift Bioreactor
Factors Affecting Microbial Bioreactor Performance
- Environment-related factors
- Temperature
- pH
- Nutrients
- Moisture
- Electron acceptor
- Reactor design-related factors
- Organism-related factors
- Pollutant-related factors
What is Phytoremediation?
Bioremediation process that employs varieties of plants to eliminate, transfer, maintain, extract or degrade contaminants in the soil and groundwater.
Mechanisms of Phytoremediation
Phytoextraction
Phytostimulation
Phytostabilization
Phytodegradation
Phytovolatilization
Rhizofiltration
Factors affecting efficiency of phytoremediation
Contaminated area
Concentration of contaminant
Plant biomass
Accumulation potential of plant
Tolerance of plants
Plant species
Advantages of phytoremediation
Environment-friendly
Cost-efficient
Long-term applicability
Multiple contaminants can be removed
Least harmful method
What is catalytic biodegradation
Sometimes referred to as “aerobic biodegradation”. It is the breakdown of organic contaminants when oxygen is present.
Catalytic biodegradation compounds
Aliphatic compounds
Halogenated aliphatics
Alicyclic hydrocarbons
Aromatic hydrocarbons
The more complex the structure is, the harder it is to degrade via aerobic degradation.
What is non-catalytic biodegradation
Sometimes referred to as
“anaerobic biodegradation”. Organic decompositions are done when oxygen is not present.
Under anaerobic conditions, organic compounds are often degraded by an interactive group or consortium of microorganisms.
Process of non-catalytic biodegradation
- Hydrolysis
- Acidogenesis
- Acetogenesis
- Methanogenesis
Catalytic vs non-catalytic biodegradation
Catalytic
Rapid degradation
No pungent-smelling gas produced
Non-catalytic
Slow process
Pungent-smelling gas produced (methane)
What are bio-based, bio-sourced, plant-based polymers
Bio-based, bio-sourced, and plant-based polymers are polymers which will mostly biodegrade in compost. Plant-based polymers are derived from plant molecules.
What is Polymerization
Polymer was formed through a process called polymerization, the chain-linking of individual rings (small molecules or monomers) with same or different sizes and compounds to form one long or large molecule; thus, the word polymer was derived (in Greek, poly means “many” and mer means “part”).
