EESA10H3 Lecture Notes - Giardia Lamblia, Arsenic Poisoning, Legionella
Chapter 3: Water Quality and Water Resources
- Water is essential to human life, and it is needed to be plentiful for human to survive.
- Industrial wastes and climate change pose both new and old threats to our water supply
- The next info is going to be about how to maintain quality and water quantity...
- We endure the potential diseases in contaminated water since the 19th century
oSome diseases include diarrheal diseases which kill 2 million annually
- Even though we have improved our ways of water sanitation, it still leaves 20% without
improved drinking supplies
- Evidence have shown that changing the means of human waste disposal is much better
than purifying your water supplies
Sources of Water
- There’s also surface water, and there’s ground water
oSurface water is
Streams, lakes, and rivers
most contaminated because it’s on the surface...being prone to chemicals
and microbial pathogens from waste runoff from nearby land
oGround water is...
Artesian or other types of wells
Not as contaminated because its beneath the soil which act as filters for
However, ground water can be contaminated if waste on top seeps
through...such as a landfill.
Once ground water is contaminated, the water stays contaminated for a
Uses of Water
- Water isn’t only to be consumed. It’s actually the least we do with water...
- 70% of water is used for agriculture
o88% in Africa (highest), and 31% in Europe (lowest)
oUS and Europe use 55% of their water for industries
oIn industries, water is used for cooling or flushing equipment, which then leads to
rivers, streams, etc. (contaminated water)
Most is used for toilet flushing, then clothes washers, and then faucets
Sources of Contamination
- Chemicals can enter into water through a number of ways...
oFertilizers and pesticides are washed away from land and brought to streams,
lakes, and rivers (surface water)
oThis can happen to animal waste in the similar fashion
oHeavy landfills can have their chemicals seep through into ground water
oEven Earth’s crust contaminates the water with arsenic and radon when water is
in contact with it
oAlso, treating water with chemicals and disinfectants have a chance for it to be
still present in our drinking water
- Sources of contaminants that discharge into receiving waters from a pipe or other
identifiable device are called “point sources”.
oThese include industrial wastes, and sewage treatment plants
- The sources of contaminants that don’t use visible pipes are called :non-point sources”
oIncluding agricultural run off, oil run off, chemicals from streets, etc, etc
- Acts such as the “US Clean water act” and the “safe water drinking act” has
tremendously reduced the amount of point source contaminants
oEven though we reduced point source contaminants, water is still vulnerable to
non-point source contaminants
Water Treatment Process
- Even though we have been treating water for a long time, the water treatment process
changes very little
- The Water Process
oWater is pumped from source.
oHeld in settling tanks, where water is treated with chlorine to get rid of microbial
pathogens and sediments
oCoagulant is then added. This makes small particles (organic matter/microbes)
stick together in water
oThen flocculation happens, when they stir the water so the particles stick
together, being heavier and larger, they’ll sink to the bottom
oSince the above steps are just to get rid of small particles, it is not chemical free.
oTreating the water with chlorine, or other forms such as ultra violet light or ozone,
is needed to disinfect the water before it gets distributed
- Reverse osmosis and other filtration techniques are becoming more common with the
demand for higher water quality.
- In developing worlds, is kind of hard to have such a complex water treatment process.
- Even though boiling water can take away chemicals, it requires energy....energy that
they don’t have.
oAlternatives have been on arise
Black water bottles to collect solar energy to heat up the water inside,
disinfecting the water!?!?! Who would want to do that
Biological Threats to our Water Quality
- WHO (World health Org.) says there are 5 ways water can be associated with human
oWaterborne: diseases transmitted from microorganisms that survive in water and
oWater washed: diseases such as trachoma and skin/eye infections that are from
inadequate washing of hands/food