Environment Impact of huamn Activities

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Tutorial

• Environment Impact of huamn Activities

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Q1. Discuss the energy issue we all concern
about. Do you think that hydrogen is truly a
clean energy source?
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Some Energy Issues

• Ever increasing in energy demand. Approx 5 PA.
• High dependence on fossil fuels for energy needs
• The largest use of energy for transport
• Significant adverse effects from the use of
  energy most noticeable in localised air
  pollution from domestic heating, and CO2
  emissions and localised pollutants from
  transport.
• Poor energy efficiency and poor control of
  emissions
• Renewable energy (eg. wind, solar) remains
  largely undeveloped
• Energy resource management
• Issues related to Nuclear Energy which contribute
  about 8 of world energy

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http//www.fueleconomy.gov/feg
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Do you think that hydrogen is truly a clean
energy source?

• (Pros) Clean energy source
• (Pros) Cheap? (Cons) Not so! Also, production of
  hydrogen not cheap!
• (Pros) Light (Cons) Storage!
• (Pros) Hydrogen powered vehicle more efficient.

NASA uses hydrogen fuel to launch the space
shuttles. Credit NASA
http//www.nrel.gov/clean_energy/hydrogen.html htt
p//carbon.cfr.washington.edu/esc110/2003winter/pr
ojects/030/hp.html http//www.h2eco.org/info.htm
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Q2. Is recycling the only solution to the
wasteful consumer society? Give your critical
comments.
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• Its hard to believe that anyone would question
  the importance of recycling but, many of the
  reasons we support recycling can not be directly
  quantified in monetary terms. Many of the
  benefits are hidden.
• RECYCLING COSTS MONEY. The expenses may include
  
• Collection, transportation and processing costs
• Capital investments such as equipment and
  container costs and labor fees
• Recycling market fees may be charged to cover the
  costs of processing certain materials

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• RECYCLING SAVES MONEY. Areas where savings occur
  may include
• Lower manufacturing costs for products made from
  recycled rather than virgin materials
• Avoiding landfill or incineration fees, still
  over 100 per ton in Passaic County, New Jersey
• The value of conserving our natural resources
• The value of saved energy by recycling materials
  rather than obtaining virgin materials
• RECYCLING CAN MAKE MONEY.
• Depending upon the quality and quantity, selling
  recyclables can bring in revenue.

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What are the raw material (or feed) use in the
production of NEWater (RO water)?

• NEWater is treated used water that has undergone
  stringent purification and treatment process
  using advanced dual-membrane (microfiltration and
  reverse osmosis) and ultraviolet technologies.
• NEWater could be mixed and blended with reservoir
  water and then undergo conventional water
  treatment to produce drinking water (a procedure
  known as Planned Indirect Potable Use or Planned
  IPU).

http//www.pub.gov.sg/NEWater
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What are the key technologies involved in the RO
water production?

• The first barrier is the conventional wastewater
  treatment process whereby the used water is
  treated to globally recognised standards in the
  Water Reclamation Plants.
• The second barrier is the first stage of the
  NEWater production process known as
  Microfiltration (MF). In this process, the
  treated used water is passed through membranes to
  filter out and retained on the membrane surface
  suspended solids, colloidal particles,
  disease-causing bacteria, some viruses and
  protozoan cysts. The filtered water that goes
  through the membrane contains only dissolved
  salts and organic molecules.

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• The third barrier or the second stage of the
  NEWater production process is known as Reverse
  Osmosis (RO). In RO, a semi-permeable membrane is
  used. The semi-permeable membrane has very small
  pores which only allow very small molecules like
  water molecules to pass through. Consequently,
  undesirable contaminants such as bacteria,
  viruses, heavy metals, nitrate, chloride,
  sulphate, disinfection by-products, aromatic
  hydrocarbons, pesticides etc, cannot pass through
  the membrane. Hence, NEWater is RO water and is
  free from viruses and bacteria and contains very
  low levels of salts and organic matters. At this
  stage, the water is already of a high grade water
  quality.
• The fourth barrier or third stage of the NEWater
  production process really acts as a further
  safety back-up to the RO. In this stage,
  ultraviolet or UV disinfection is used to ensure
  that all organisms are inactivated and the purity
  of the product water guaranteed.

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Do you think that NEWater is safe for human
consumption? State your major concerns.How you
overcome these concerns?

• NEWater is cleaner than PUB Water (Colour)
• Comprehensive analyses of NEWater to ensure that
  the water quality is indeed good. These analyses
  are supervised by a panel of local and
  international experts.
• So far 20,000 analyses over the last two years
  have been conducted and these have established
  that NEWater is cleaner than PUB water.
• Physically, NEWater is very clear and sparkling.
  The river sources and reservoir water has more
  color as they contain more minerals and organic
  substances.

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(No Transcript)
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Quadrillion1015, British thermal unit
(Btu)1.05?103 Joules
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Present Energy Resources
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OIL and NATURAL GAS

• Oil reserves are expected to exhaust
• by 2040 at present rate of production and
• by 2020 if the production increases by 6 per
  year.

• This will lead to
• rise in oil price,
• the struggle for the control over remaining oil
  supply.

Natural gas reserves 1412 trillion cubic meters
another 60 years.
Relatively Clean But still CO2 problem
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• Powered the industrial revolution
• Estimated Reserves 220 Years
• A typical coal power station emits each year
  about
• eleven million tons of carbon dioxide,
• twenty nine thousand tons of nitrous oxide,
• sixteen thousand tons of sulphur dioxide,
• range of chemicals Al, Ca, K, Ti and As,
• Caused acid rain
• Green House Effect
• Coal also contains Uranium radioactivity problem

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Hydroelectric Power
Inexhaustible (Renewable) source. Hydropower,
even at its maximum utilization, will not be able
to provide more that 10 the world energy demand.

• Geographic constraints,
• No polluting material,
• But severely affects the environment and natural
  habitat by submerging huge areas

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Solar Energy
Earth receives about 88000 TW (200 W per square
meter ) from sun - enough to meet our demand many
thousand times.
Considering 25 efficiency, one require a 50-100
square km collector to produce electricity as
produced by typical power station.

• Requirements of
• sunny climate,
• large collector area and
• large energy storage system
• make solar power much costly and unattractive.

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Nuclear Fission Energy Most important near term
replacement for fossil fuels.
Fission Fragments
High N/Z Ratio than light nuclei
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Energy reserves (non-breeder fission reactors)
3000 quadrillion Btu
Fast breeder reactor (FBR)
Estimated energy reserves with FBR will be
3,50,000 quadrillion Btu.
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Uranium reserves for non-FBR are not more that
100 years.
FBR safety was undermined by 1995 accident at
Monju, Japan, so many countries (US, UK, France)
have curtailed their FBR research.
Moreover, thermal reactor provides energy at much
cheaper cost.

• The nuclear fission suffers from
• accidental radioactive release, (Three Mile
  accident in US and Chernobyl disaster in former
  Soviet Union),
• waste disposable management and
• proliferation of nuclear weapon material.

The Mission To develop a relatively clean AND
long-term alternative energy source.
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Acid Rain
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The Green House Effect