In this article we will discuss about the Water:- 1. Definition of Safe and Wholesome Water 2. Uses of Water 3. Sources 4. Water Pollution 5. Diseases 6. Law 7. Purification.
- Essay on the Definition of Safe and Wholesome Water
- Essay on the Uses of Water
- Essay on the Sources of Water Supply
- Essay on the Water Pollution
- Essay on the Water-related Diseases
- Essay on the Water Pollution Law
- Essay on the Purification of Water
Essay # 1. Definition of Safe and Wholesome Water:
It is defined as water which is:
(a) Free from pathogenic agents.
(b) Free from harmful chemical substances.
(c) Free from colour and odour.
(d) Usable for domestic purposes.
Water is said to be polluted when it does not fulfil the above criteria.
Essay # 2. Uses of Water:
a. Domestic Use:
Water is required for drinking, cooking, washing, bathing, flushing of toilets, gardening, etc.
b. Public Purposes:
Water is used for cleaning streets, swimming pools, public fountains, fire protection and public parks.
c. Industrial Purposes:
Water is used for processing and cooling.
d. Agricultural Purposes:
It is used for irrigation.
e. Power Purposes:
It is used for power production from hydropower and steam power.
f. Waste Removal Purpose:
It is also used for the removal of waste from all manner of establishments and institutions.
Essay # 3. Sources of Water Supply:
Three main sources of water are:
b. Surface water: Rivers and streams, impounding reservoirs, tanks, ponds and lakes.
c. Ground water: Shallow wells, deep wells, springs.
(a) A part of the rain water sinks into the ground, some forms streams and rivers which flow ultimately into the sea.
(b) Some of the water in the soil is taken up by the plants and is evaporated by the leaves.
(c) Physically, it is clear, bright and sparkling.
(d) Chemically, it is very soft water containing traces of dissolved solids.
(e) Bacteriologically, it is free from pathogenic agents.
(f) It becomes impure as it picks up suspended impurities from the atmosphere such as dust, micro-organisms and gases such as carbon dioxide, nitrogen, oxygen and ammonia.
(g) Gaseous sulphur and nitrogen oxides are eliminated from power plants. These gases react with atmospheric water forming dilute solutions of sulphuric acid and nitric acid. The acid rain causes serious affects on plants and on surface water quality.
b. Surface Water:
It originates from rain water. It is the main source of water supply in many areas. It is contaminated from human and animal sources and hence it is never safe for human consumption unless purified before use
(i) Impounding reservoirs:
(a) These are artificial lakes constructed of earthwork or masonry in which large quantities of surface water is stored.
(b) Dams and mountain streams also provide large reserves of surface water.
(c) Algae and other microscopic organisms are grown in storing water in reservoirs imparting bad odours and tastes to water.
(d) These reservoirs are having good quality of water. The water is usually clear and palatable if the surrounding hills are covered with peat. The water is soft and free of pathogenic organisms.
(a) The river water is on the whole polluted and is quite unfit for drinking without treatment.
(b) River water contains dissolved and suspended impurities of all kinds. The bacterial count in it is very high.
(c) The impurities of river water are derived from sewage, industrial and trade wastes, and drainage from agricultural areas. The water is polluted by bathing, animal washing and disposal of the dead.
(d) Self-purification of river water accurse by dilution, sedimentation, aeration, oxidation, sunlight. But this is not sufficient to render the water potable. The water needs purification before drinking purposes.
(a) Surface water is stored in tanks and tanks are having contaminated water of all sorts.
(b) Tank water contains colloidal matters immediately after the rains. The older tanks are full of aquatic vegetation.
(c) Tanks are used for washing of clothes, cattle, humans, cooking pots and are also used for swimming purposes. Hence, the water becomes fully contaminated and the water cannot be drunk without boiling.
(d) Sea water contains 3.5 percent of salts in solution, 19,000 mg/litre of chloride, 10,600 mg/litre of sodium, and 1270 mg/litre of magnesium. Heavy expenditure is involved in desalting and demineralization.
Ground water is superior to surface water, because it has an effective filtering medium. It is mostly free from pathogenic agents and does not require any treatment. It is less contaminated than surface water. It contains salts of calcium and magnesium which make the water hard. The ground water sources are wells and springs. Wells are classified into shallow and deep wells, dug and tube wells.
(a) Shallow wells produce limited quantities of water and the water is liable to pollution unless well-constructed.
(b) Deep wells are usually machine-dug and are several hundred meters deep. These wells are satisfactory sources of water supply.
(c) Shallow wells are polluted from neighbouring sources of contamination such as latrines, urinals, drains and collections of manure.
According to construction, wells may be classified into dug wells and tube wells. Dug wells are of two types—katcha well and pucca well. In these wells, there is personal contact between the user and the water. Some people may even wash their faces, hands and feet which is a common Indian custom.
Tube wells are beneficial as a source of drinking water in many parts of India. They produce water which is bacteriologically safe and also cheap.
(a) Ground water when comes to the surface and flows freely under natural pressure is called a “spring”.
(b) Springs are of two types—Shallow springs and deep springs. Shallow springs dry up quickly during summer months, whereas deep springs do not show seasonal effect in the flow of water.
(c) Springs are exposed to contamination. Well protective structures are essential to safeguard water supply.
Essay # 4. Water Pollution:
a. Pure water does not occur in nature. It contains natural and man-made impurities.
b. The natural impurities are dissolved gases (carbon dioxide, nitrogen, hydrogen sulphide, etc.), suspended impurities (clay, sand, mud, etc.), and microscopic organisms and dissolved minerals (salts of calcium, magnesium, sodium etc.).
c. Water pollution is seriously caused by urbanization and industrialization. Sewage contains decomposable organic matter and pathogenic agents. Industrial wastes contain toxic agents. Agricultural pollutants contain fertilizers and pesticides. Physical pollutants contain heat and radioactive substances.
d. Even after treatment properly, water pollution still occurs due to corrosion of pipelines, leaky joints, and cross-connections between water supply pipes and sewage drainage pipes.
A. Biological (water-borne diseases):
a. Those caused by the presence of an infective agent:
(i) Protozoal: amoebiasis, giardiasis.
(ii) Helminthic: roundworm, threadworm.
(iii) Viral: viral hepatitis A, hepatitis E, poliomyelitis.
(iv) Bacterial: typhoid and paratyphoid fever, bacillary dysentery, cholera, E. Coli diarrhoea.
(v) Leptospiral: Weil’s disease.
b. Those due to the presence of an adequate host:
(i) Snail: Schistosomiasis.
(ii) Cyclops: Fish tape warm, Guinea worm.
a. Chemical pollutants include detergent solvents, cyanides, minerals, heavy metals, organic acids, bleaching agents, dyes, pigments, sulphides, ammonia, and toxic substances.
b. Chemical pollutants may affect man’s health by accumulating fish used as human food.
c. Some new pollutants are not easily removed by water treatment or purification processes.
d. High levels of fluoride cause mottling of the dental enamel.
e. Methemoglobinemia may occur when surface water from farmland, treated with a fertilizer, gain access to the water supply.
f. Hardness of water causes beneficial effect against cardiovascular disease.
g. Some diseases are transmitted due to inadequate use of water like trachoma, conjunctivitis, ascariasis.
h. Some diseases are related to the disease carrying insects breeding in or near water like malaria, filaria, etc.
Essay # 6. Water Pollution Law:
In India, water pollution is a serious problem. In 1947, parliament passed the Water (prevention and control of pollution) Act to protect water from being contaminated. The Act seeks to provide legal action against the spread of water pollution.
Essay # 7. Purification of Water:
Purification of water is done:
a. On a large scale.
b. On a small scale.
a. Purification of Water on a Large Scale:
Ground water (wells and springs) does require no treatment except disinfection. Surface water (river water) requires extensive treatment since it is turbid and polluted.
Purification system depends on one or more of the following methods:
(a) As a result of storage, 90 per cent of the suspended impurities settle down in 24 hours by gravity.
(b) The aerobic bacteria oxidize the organic matter present in the water by the help of dissolved oxygen. The content of free ammonia is reduced.
(c) The pathogenic organisms gradually die out. The total bacterial count drops.
(d) If the water is stored for long periods, there is development of vegetable growths such as algae which cause a bad smell.
(a) 99 per cent of the bacteria are removed by filtration in addition to other impurities.
(b) There are two types of filters—the “biological” or “slow sand” filters and the “mechanical” or “rapid sand” filters.
(c) The cost of construction of slow sand filters is cheaper than that of rapid sand filters. The physical, chemical and bacteriological quality of filtered water is very high.
(d) Rapid sand filters are of two types—the gravity type (Paterson’s filter) and the pressure type (Candy’s filter). The filter beds occupy less space. The filtration is rapid and the washing of the filter is easy.
(a) Disinfection is capable of destroying the pathogenic organisms present.
(b) Chlorine kills pathogenic bacteria but it has no effect on spores and certain viruses except in high doses. It oxidizes iron, manganese and hydrogen sulphide. It destroys some taste and odour producing constituents. It controls algae and slime organisms.
(c) Ozone eliminates undesirable odour, taste and colour, and removes all chlorine from the water. It has a strong virucidal effect. After the work, ozone decomposes and disappears and it does not have germicidal effect. Therefore, ozone is used as a pre- treatment of water to destroy not only viruses and bacteria but also organic compounds.