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Application of Environmental Biotechnology - Coggle Diagram
Application of Environmental Biotechnology
2.0 Biotechnological Treatment
Disadvantages
There may be unexpected or negative effects of applied microorganisms such as emission of cells, odors or toxic gases during biotreatment
Optimal conditions must be maintained in the treatment system
Nutrients and electron acceptors must be added to intensify the biotreatment
There may be unexpected problems in the management of the biotechnological system because
of the complexity and high sensitivity of the biological processes
Main considerations
Large volume of treated wastes
A low concentration of pollutant in water or waste is preferred
Technically and economically reasonable rate of biodegradability or detoxication of waste substances during biotechnological treatment
The ability of natural microorganisms to degrade waste substances
Better public acceptance of biotechnological treatment
Advantages
A diverse set of conditions that are suitable for biotechnological methods
Availability of a wide range of biotechnological methods for complete destruction of hazardous
wastes
Biodegradation or detoxication of a wide spectrum of hazardous substances by natural microorganisms
3.0 Aerobic Treatment
Liquid Waste
Co-metabolism
Simultaneous biodegradation of hazardous organic substances and stereochemically similar substrates (source of carbon and energy for microbial cells)
Applications
: Degradation by bacterial enzyme for oxidization of methane or ammonia as main energy source.
Granular activated carbon (GAC) fluidized bed reactors
Ensure sorption of hydrophobic hazardous substance on the surface of GAC
Pre-treatment
Removal from wastewater or concentration of hazardous substances
Preliminary oxidation, preliminary photo-oxidation & electrochemical oxidation
Mechanical disintegration
Gaseous Waste
Applications
Bioremoval of biodegradable organic solvents, odors and toxic gases
Bioscrubber
Contain suspensions of biodegrading microorganisms
Biofilter
Packed with porous carriers covered by biofilms of degrading microorganisms
Solid Waste
Composting
Benefits
Destruction of pathogens and parasites
Retention nutrients in the end product
Prevent waste odors
Technology
Static pile system
In-vessel system
Windrow system
Converts biologically unstable organic matter into more stable humus-like product
Pre-treatment
Thermal treatment
Washing of waste
Mechanical disintegration
Chemical pre-treatment
4.0 Anaerobic Treatment
Advantages
no need to supply oxygen in system
useful for bioremediation of clay soil or high strength organic waste
Disadvantages
slower than aerobic treatment
may be significant outputs of dissolved organic products of fermentation or anaerobic respiration
Treatment
Anaerobic respiration
Effective in terms of output of energy per mole of transferred electrons
Performed by prokaryotes with electron acceptors
Anaerobic fermenting bacteria
Hydrolyze different natural polymers
Ferment monomers with production of alcohols, organic acid and CO2
Facultative anaerobes
Produce energy from reactions or aerobic oxidation
Useful when integrated with aerobic / anaerobic microorganisms in microbial aggregates
Anaerobic microorganisms
Slowly transform organic and inorganic wastes
Anaerobic/aerobic
Sequential nitrogen removal including aerobic nitrification and anaerobic denitrification
Reduction of sulfate or Fe(III) wit production of H2S or Fe(II)
Biodegradation of chlorinated aromatic hydrocarbons including anaerobic dichlorination and aerobic ring cleavage
5.0 Treatment of Heavy Metals- Containing Waste
Treated by biotechnological method
Microbial production of phosphate, H2S, and CO2 will stimulate precipitation of non-dissolved phosphates, carbonates, and sulfides of heavy metals
Production of H2S by sulfate-reducing bacteria is useful to remove heavy metals and radionuclides from sulfate containing mining drainage waters
Microbial production of organic acids in aerobic oxidation will promote formation of dissolved chelates of metals.
The surface of microbial cells is covered by negatively charged carboxylic and phosphate groups, and positively charged amino groups. The adsorption of heavy metals onto the microbial surface depend on pH.
Microbial metabolism generates products such as hydrogen, oxygen, H2O2, which can be used for oxidation/reduction of metals (accompanied by metal solubilization or precipitation).
Metal-containing minerals such as sulfides can be oxidized and metals can be solubilized for the purpose of for the bioleaching of heavy metals from sewage sludge before
landfilling or biotransformation
6.0 Enhancement of Biotechnological Treatment of Waste
Environmental Factors
Control pH of microbial biotopes (pH 1 -11)
Addition of a pH buffer or pH regulator
Control of organic acid formation in fermentation
Prevention of formation of inorganic acids in aerobic oxidation
Assimilation of ammonium, nitrate, or ammonium nitrate, leading to decreased pH, increased pH, or neutral pH,
Solutions of KOH, NaOH, NH4OH, Ca(OH)2, HCl, or H2SO4 can be added automatically to maintain the pH of liquid in a stirred reactor
Control temperature of microbial growth (10 to 90◦C ）
The heating of the treated waste can come from microbial oxidation or fermentation activities, providing sufficient heat generation and good thermal isolation of treated waste
Dissolved oxygen concentration
oxygen consumption rates ranging from 10 to 2,000 g O2/Lxh
Oxygen sources (increase oxygen transfer rate)
Pure oxygen (5 times increase)
Air supply with aeration and mechanical agitation
Hydrogen peroxide
Dissolved acceptors of electrons (NO−3,NO−2, Fe3+, SO2−4, and HCO−)
Techniques
Fixed biofilm reactors
viscous solid wastes
underground layers of soil
aquifers polluted by hazardous substances
Contaminants and nutrients must be available for action or assimilation by microorganisms
Nutrient
Purpose
Essential for microbial growth and enzymatic activities and must be added into the treatment systems if present in low concentrations in the waste.
Examples
Major elements (C, H, O, N, S, and P)
Other macronutrients (K, Mg, Na, Ca, and Fe)
Micronutrients (Cr, Co, Cu, Mn, Mo, Ni, Se, V, and Zn)
Organic compounds (vitamins, aminoacids, and nucleosides)
Essential metals are their dissolved salts or chelates with organic acids.
Content and activity of essential microorganisms in the treated waste must be sufficient for the treatment
Addition of microorganisms (inoculum) to start up or to accelerate a biotreatment process/
Common environment engineering practice （Pure starter cultures）
Recombinant DNA techniques or genetic engineering
Purpose
create new, artificial combinations of genes, and increase the number of desired genes in the cell
7.0 BIOSENSORS
Purpose
Monitoring of biodegradability, toxicity, mutagenicity, concentration of hazardous substances, and monitoring of concentration and pathogenicity of microorganisms in wastes and in the environment.
Examples
Bioluminescence toxicity bioreporter
Measuring toxicity
Luminescent reporter gene
Determine changes in the metabolic status of the cells
Respirometric sensors
Measuring respiration rates of these bacteria for toxicity monitoring in wastewater treatment
Bioluminescence
Measuring concentrations of hazardous substances
Mutant bacterial strains
Determine the potential mutagenicity of manufactured or natural chemicals.
Detecting enzymes, sequences of nucleic acids (RNA or DNA), antibodies, polysaccharides or other “reporter” molecules
Examples
Antibodies
monitoring the fate of bacteria released into the environment for the treatment of a polluted site.
Fluorescent or enzyme-linked immunoassay
A variety of contaminants, including pesticides and chlorinated polycyclic hydrocarbons.
Enzymes
Attached to matrices detecting interactions between enzymes and pollutants are used in on-line biosensors of water and gas biotreatment
Microarrays
Simultaneous semi-quantitative detection of different microorganisms or specific genes in the environmental sample
Radioactive labels, fluorescent labels
Increase sensitivity and simplicity of the hybridization
detection
1.0 Introduction
System related to the use microorganism and their products in the prevention, treatment, and monitoring of environmental pollution
Biotechnological agents: Bacteria and Archaea, Fungi, Algae, and Protozoa.
Main Application: biodegradation of organic matter of municipal wastewater and biodegradation/ detoxication of hazardous substances in industrial wastewater.
prevention of pollution
restoration of water quality in reservoirs, lakes and rivers, coastal area, in aquifers of ground water, and treatment of potable water
Areas of environmental biotechnology
prevent hazardous waste production using biotechnological analogs
develop biodegradable materials for environmental
sustainability
tests of toxicity and pathogenicity,
biosensors, and biochips to monitor quality of environment
produce fuels from biomass and organic wastes, and
reduce toxicity by bioimmobilization of hazardous substances