Purification of Water : a Study

1707 Words Sep 12th, 2012 7 Pages
Chemistry Investigatory Project

To determine minimum amount of
Bleaching Powder
Required to disinfect different samples of Water.

INDEX I. Introduction o Purification of Water o History of Water Purification o Bleaching Powder

II. Experiment o Aim o Requirements o Theory o Procedure o Observations o Result o Precautions


98% of the Earth’s water is present in the oceans with an average salinity of 3.5%. The remainder of the Earth's water constitutes the planet's fresh water resource. Typically, fresh water is defined as water with salinity below around 0.035%.
The planet's fresh water is also very unevenly distributed. About 68.7% of the freshwater is deposited in
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The treatment and distribution of water for safe use is one of the greatest achievements of the twentieth century. Before cities began routinely treating drinking water with Chlorine, Cholera, Typhoid, Dysentery and Hepatitis A killed thousands of U.S. residents annually. Drinking water chlorination and filtration have helped to virtually eliminate these diseases in the U.S. and other developed countries.
Meeting the goal of clean, safe drinking water requires a multi-barrier approach that includes protecting source water from contamination, appropriately treating raw water, and ensuring safe distribution of treated water to consumers’ taps.
During the treatment process, chlorine is added to drinking water as elemental chlorine, sodium hypochlorite solution or dry calcium hypochlorite. When applied to water, each of these forms “free chlorine,” which destroys pathogenic organisms. Almost all systems that disinfect their water use some type of chlorine-based process, either alone or in combination with other disinfectants.

But due to the side effects of the usage of Chlorine, it was slowly replaced by bleaching powder across the world. Bleaching powder is added as part of the drinking water treatment process.

However, bleaching powder also reacts with the organic matter, naturally present in water, such as decaying leaves. This chemical reaction forms a group of chemicals known as disinfection by-products. Current
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