Section I 1.If incineration can be effective fordestroying contaminants, why isn’t it used more often? What other similartechnique could be used in its place and explain why? 2.What kind of...

Ans no. 1: Incineration is process of waste treatment where organic compounds are
combusted in a waste. Incineration is particularly very effective in removing biological
contaminants like pathogens, toxins and spores produced by pathogens in hazardous waste,
medical waste and laboratory wastes (European Commission, 2006). The major disadvantage
is that Incineration produces ash, flue gas, heat and pollutants which are not safe for living
organisms and environment surrounding them. Incineration may produce toxic waste like
heavy metal (vanadium, manganese, chromium, nickel, arsenic, mercury, lead, and cadmium)
which can be very dangerous even in low concentration. For these reasons incineration is not
most likely the choice. Presently new and alternative technologies are employed which are
more efficient and less hazardous. Some examples of such technologies are discussed below
Mechanical Biological treatment: Employs composting and anaerobic digestion of mixed
house hold waste and industrial and commercial waste.
Anaerobic Digestion: Involves microorganisms which degrade biodegradable waste materials
and produce some products which have market value like bioethanol, biodiesel, polymers and
animal feed (European Commission, 2006).
Autoclaving: The most commonly used sterilizing process in case of a biological
contamination. Involve use of high temperature and pressure in a metal container which kills
biological contaminants.
Radiation: This is applied for that type of material which cannot be autoclaved.
Plasma Gasification: Converts organic matter into synthetic gas using plasma technique.
Mechanical heat treatment: Involve mechanical sorting followed thermal treatment.
As all these techniques are quite efficient produces very less or no pollutants these are now
commonly used for removal of contaminants.
Ans no. 2: Ground water is the major source of drinking water for living organisms. But due
to some physical activities some contaminants reach ground water and contaminate them.
This contaminated water can be hazardous for living organism. So treatment is necessary.
One of the methods of treatment is using activated carbon (Odell, 2009). This activated
carbon has large surface area, so it adsorbs contaminants present in water. The other methods
are described below.
SECTION-I
http://en.wikipedia.org/wiki/Vanadium
http://en.wikipedia.org/wiki/Manganese
http://en.wikipedia.org/wiki/Chromium
http://en.wikipedia.org/wiki/Nickel
http://en.wikipedia.org/wiki/Arsenic
http://en.wikipedia.org/wiki/Mercury_%28element%29
http://en.wikipedia.org/wiki/Lead
http://en.wikipedia.org/wiki/Cadmium
Biological treatment Technique:
Bioventing:In this technique oxygen and some nutrients are infused into the contaminated
water to enhance the activity of indigenous microorganisms and degradation of contaminants
by them.
Bio augmentation: In this process live microbial strains are inoculated into the contaminated
water which is known for degrading that type of contaminant.
Biosparging: This process is similar to bioventing but this system is used for removal of
petroleum contamination (Odell, 2009).
Phytoremediation: Some types of plants are known to accumulate heavy metals from soil and
water. These plants absorb heavy metals and accumulate them freeing the water from
contamination. E.g.: Chinese Ladder Fern, cottonwood tree
Permeable Reactive Barrier:
Chemical Treatment Technique:
Chemical Precipitation: Involves addition of a chemical agent and removes hardness and
heavy metal.
Ion-exchange: Ion-exchange resins are employed to specifically trap ionic contaminant.
Chemical oxidation: Chemical oxidants are infused to the contaminated water which
enhances natural oxidation and degradation process (Odell, 2009).
Some other treatments such as Air sparging, Dual-phase vacuum extraction and Surfactant
enhanced recovery can be employed.
Ans no. 3: VOCs or Volatile Organic Compounds are chemical compounds with very low
boiling point. These VOCs are soluble in water and contaminate soil and groundwater. So
removal of VOCs from ground water becomes necessary as this water is consumed by
humans and other organisms. Air sparging is one of the efficient techniques used to remove...