2. SOURCES OF WATER
1. Groundwater
2. Lakes and reservoirs
3. Rivers, canals and low land reservoirs
4. Rainwater harvesting
5. Surface Water
6. Atmospheric water generation
Note:
Atmospheric water generation is a new technology that can provide
high quality drinking water by extracting water from the air by cooling
the air and thus condensing water vapor
3. Water purification
It is the process of removing undesirable chemicals, biological
contaminants, suspended solids and gases from water.
Most water is disinfected for human consumption i.e. for drinking and
hence it is important the water to be purified.
Purpose for water purification:
•Drinking water
•For medical needs
•Pharmalogical
•Chemical and Industrial application
4. Water purification
Purifying water may reduce the concentration of particulate matter
including suspended particles, parasites, bacteria, algae, viruses,
fungi, as well as reducing the concentration of a range of dissolved
and particulate matter.
The standards for drinking water quality are typically set by
governments or by international standards.
These standards usually include minimum and maximum
concentrations of contaminants, depending on the intended purpose
of water use
5. WATER CONTAMINANTS IN DRINKING WATER
Particulates
Smaller and smaller micron sizes particles present
Bacteria
This includes bacteria, virus, pathogens, and more.
Minerals
Minerals include natural dissolved minerals from the rocks in the ground, heavy
metals that are the bi-product of industry and manufactured waste.
Staining on fixtures is a result of dissolved minerals that have oxidized on the
toilets, sinks, tubs, showers, clothes etc.
Orange, brown and yellow stains usually signify the presence of iron.
•White deposits generally come from calcium; hard water is an excess of calcium
and magnesium.
•Manganese leaves grey and black deposits and makes the whites in the laundry to
come out grey.
•Blue usually means that the water is acidic and is corroding the copper pipes.
•A slight yellowish, greenish or bluish hue in the water when viewed in a white
five-gallon bucket in daylight generally signifies the presence of tannin.
6. Chemicals
Chemicals are in the air we breathe and are carried in the soil via
ground water.
Rain drops are formed around tiny particles, many of which are pollutants in the
atmosphere.
A fuel known as Jet fuel is in the blood of every living creature on earth. Cases of
ADHD, autism, neural disorders, physical deformities, and more are on the rise.
Toxic coalitions are battling big industry. Most home owners purchase cleaning
products made with harmful ingredients and are oblivious of the fact that much of
these chemicals ultimately end up in our water.
Pharmaceuticals
Many of the drugs are thrown in the landfill or flushed down the toilet.
Either way, they do not go away.
Many scientists have found deformed fish containing pharmaceuticals in their
blood, have done water tests on water that has been officially approved for
municipal consumption with the results of not hundreds but thousands of toxins
in the water; many of these toxins are pharmaceuticals.
7. METHODS OF WATER PURIFICATION
1.SEPERATION –HEAT/ LIGHT & GRAVITY
A. SEDIMENTATION - It gravitationally settles heavy suspended
material.
B. BOILING WATER – Water boiled for 15 to 20 minutes kills 99.9%
of all living things and vaporizes most chemicals.
C. DISTILLATION - It boils and recondenses the water, but many
chemicals vaporize and recondense in concentration in the
output water. It is also expensive to boil & cool water.
D. ULTRAVIOLET LIGHT - It is a good substance that kills bacteria,
but works only in clearly filtered water.
8. METHODS OF WATER PURIFICATION
2.CHEMICALS
A. CHLORINE - It is common, cheap, but extremely toxic.
It does not decrease physical or chemical contamination, but it increases
cholesterol formations and causes heart disease.
A. BROMINE- It is used in pools and spas, doesn't smell or taste as bad and
doesn't kill bacteria very well.
B. IODINE - It is not practical, and is mostly used by campers.
C. HYDROGEN PEROXIDE- It kills bacteria with oxygen, is chemically made and is
very toxic. It is used in emergencies.
D. SILVER – It is an effective bactericide but a cumulative poison which
concentrates and doesn't evaporate.
E. NONTOXIC ORGANIC ACIDS - It should be used with caution in large water
plants only.
G. ION EXCHANGE - It exchanges sodium from salt for calcium or magnesium,
using either glauconite (greensand), synthetic organic resins etc. thus
softening the water.
Minerals, metals, chemicals or odors are not affected, and the water is salty to
drink
9. METHODS OF WATER PURIFICATION
3.FILTRATION
A. SAND PROCESS:
• Slow sand of 1 cubic meter passes about 2 l/min, and does a limited bacteria
removal.
• Pressure sand of 1 cubic meter passes about 40g/m and must be backwashed
daily.
B. POROUS STONE/CERAMIC :The filters are small but expensive, and do not
effect chemicals, bacteria or odors.
C. PAPER or CLOTH -The filters are disposable and filter to one micron, but do
not have much capacity.
D. CHARCOAL: COMPRESSED CHARCOAL/CARBON BLOCK is the best type of
charcoal filter, it can remove chemicals and lead.
E. REVERSE OSMOSIS - It uses a membrane with microscopic holes that require 4
to 8 times the volume of water processed to wash it in order to remove
minerals and salt, but not necessarily chemicals and bacteria.
F. PLANTS -There are numerous plants, animals and organisms that are quite
effective in filtering water.
10. METHODS OF WATER PURIFICATION
4. OXYDATION –Reducing the compounds
A. AERATION -It sprays water into the air to raise the oxygen content, to break
down odors, and to balance the dissolved gases.
B. OZONE - is a very good bactericide, using highly charged oxygen molecules to
kill microorganisms on contact, and to oxidize and flocculate iron, manganese
and other dissolved minerals for post-filtration and backwashing.
C. ELECTRONIC PURIFICATION -
It creates super oxygenated water in a dissolved state that lowers the surface
tension of the water and effectively treats all three types of contamination:
physical, chemical and biological.
12. Rainwater harvesting
Rainwater harvesting is the accumulation and storage of rainwater
for reuse on-site, rather than allowing it to run off.
It can be collected from rivers or roofs, and in many places, the water
collected is redirected to a deep pit (well, shaft, or borehole), a
reservoir with percolation, or collected from dew or fog with nets or
other tools.
Its uses include water for gardens, livestock, irrigation, domestic use
with proper treatment, indoor heating for houses, etc.
The harvested water can also be used as drinking water, longer-term
storage, etc.
It is one of the simplest and oldest methods of self-supply of
water for households usually financed by the user.
13. Advantages :
1. It provides water when a drought occurs, and reduces demand
on wells which may enable groundwater levels to be sustained.
2. It also helps in the availability of potable water, as rainwater is
substantially free of salinity and other salts
3. Applications of rainwater harvesting in urban water system is
beneficial for both water supply and waste supply.
4. It is used to supplement the main supply.
Applications:
• Agriculture
• Domestic use
• Industries
14. STORM WATER SUPPLY
Storm water is the water that originates during precipitation events
and snow/ice melt.
It can soak into the soil, be held on the surface and evaporate,
or runoff and end up in nearby streams, rivers, or other water
bodies.
In natural landscapes such as forests, the soil absorbs much of the
storm water and plants help hold storm water close to where it falls.
In developed environments, unmanaged storm water can create
two major issues: one related to the volume and timing of runoff
water (flooding) and the other related to potential contaminants
that the water is carrying (water pollution).