Why microorganisms are nowadays frequently used instead of chemicals to bioremediate pollution?
Microorganisms (primarily bacteria and fungi) are nature's original recyclers. Their capability to transform natural and synthetic chemicals into sources of energy and raw materials for their own growth suggests that expensive chemical or physical remediation processes might be replaced with biological processes that are lower in cost and more environmentally friendly.
Scenario 1: Metal Removal in Fluid Environment Using Chemical Treatment
Disadvantages:
• Corrosive chemicals are required for use (sulfuric acid, sodium hydroxide).
• Chemical treatment is very sensitive to changes in emulsifier (surfactant) chemistry.
• Specialized instruments are required (pH meter).
• Instruments require frequent calibration (pH meter).
• Chemical changes and/or meter malfunctions can result in poor water quality without notice.
• Balancing chemical reactions, at times, can be more an art than a science.
• Synthetic fluids cannot be effectively treated by this method.
• The basic concepts of this method are abstract and are not easily understood by persons without some chemistry background.
Scenario 2: Disinfection in Water Treatment
Disadvantages:
Excess chlorine in water can combine with organic material in the water to form substances such as trihalomethanes, which can cause liver, kidney, or central nervous system problems, and are linked to an increased risk of cancer over a lifetime exposure.
Scenario 3: Pre-tanning processes of Leather Processing
Disadvantages:
Chemicals such as lime, sodium sulphide, and caustic soda are introduced in soaking, dehairing, bating, degreasing and offal treatment. The tannery effluents are released into the rivers and streams contaminating with the toxic chemicals. Therefore, leather industry contributes to one of the major industrial pollution problems facing countries such as India.
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