WATER
PURIFICATION
Submitted by: submitted to:
Prathana Shrestha
XI (SMC)
Water
◦ Water is an inorganic compound with the chemical formula H2O. It is a
transparent, tasteless, orderless, and nearly colorless chemical substance. It is
the main constituent of earth’s hydrosphere and the fluids of all known living
organisms. It is vital for all known forms of life, despite not providing food
energy or organic micronutrients. Its chemical formula, H2O indicates that each
of its molecules contains one oxygen and two hydrogen atoms, connected by
covalent bonds. The hydrogen atoms are attached to the oxygen atom at an
angle of 104.45 degree. In liquid from, H2Ois also called “water” at standard
temperature and pressure.
◦ Water covers about 71% of the earth’s surface, with seas and oceans making up
most of the water volume (about 96.5%). Small portions of water occur as
groundwater(1.7%), in the glaciers and the ice caps of antarctica and
Greenland (1.7%), and in the air as vapor, clouds (consisting of ice and liquid
water suspended in air),and precipitation (0.001%). Water moves continually
through the water cycle of evaporation, transpiration (evapotranspiration),
condensation, precipitation, and runoff, usually reaching the sea.
Importance
◦ Water plays an important role in the word economy.
Approximately 70% of the fresh water used by humans goes to
agriculture. Fishing in salt and fresh water bodies has been, and
continues to be, a major source of food for many protein. Much
of the long-distance trade of commodities is transported by
boats through seas, rivers, lakes, and canals. Large quantities of
water, ice and steam are used foe cooling and heating. Water is
an excellent solvent for a wide variety of substance, both mineral
and organic; as such, it is widely used in industrial processes and
in cooking and washing. Water, ice and snow are also central to
many sports and other forms of entertainment, such as swimming,
diving, ice skating, snowboarding etc.
Purification of water
◦ Water purification is the process of removing undesirable chemicals,
biological contaminants, suspended solids, and gases from water. The goal is to
produce water that is fit for specific purposes. Most water is purified and
disinfected for human consumption , but water purification may also be carried
out for a variety of other purposes, including medical, pharmacological,
chemical, and industrial applications. Water purification can reduce the
concentration of particulate matter including particles, bacteria, algae, viruses,
and fungi as well as reduce the concentration of a range of dissolved and
particulate matter.
Methods of purification of water
◦ There are several methods for purifying water, each suitable for different
contaminants and purposes. Here are some common methods:
1) Boiling: Heating water to a rolling boil for at least one minute kills most
bacteria, viruses and parasites. Heating water to 100degree Celsius or
212degree Fahrenheit.
2) Chemical treatment: Adding chemicals such as chlorine or iodine to
disinfect water. This method is effective against bacteria and viruses but
may leave residual taste. It kills bacteria and viruses, but may may remove
all contaminants. It is best for disinfection, especially in emergency
situations.
Methods of purification of water
Filtration
Using physical barriers (like sand, charcoal, or specialized filters) to remove
impurities and microorganisms. This includes:
Activated carbon filters: effective for organic compounds and chlorine.
◦ Reverse osmosis :removes a wide range of impurities, including salts and
heavy metals.
◦ Ceramic filters: effective for removing bacteria and sediments.
◦ Best for: physical, chemical, and biological contamination
Methods of purification of water
5) Sedimentation: allowing suspended6) Activated carbon adsorption:
particles to settle at the bottom of a water passes through a bed of
container, which can then be activated carbon which absorbs
separated from the clear water organic contaminants, chorine and
above. It removes suspended solids other chemicals. It removes chorine
and large particles. It is best for volatile organic compounds, and
large scale water treatment, some other pollutants. It is best for
especially for muddy or turbid improving taste and order, as well as
water. adding chemicals coagulants removing certain chemicals.
to water causes particle to clump.
