Water Supply

Water Supply

Water is an important part of nature which surrounds us and of those natural conditions, we are changing constantly and ever more intensively: the flora, the soil, the mountains, mineral resources, the deserts, the marshes, the steppes and the taiga.Water passes through a very interesting natural cycle.The atmosphere which surrounds the earth's surface contains water which varies in amount in direct proportion to the temperature of its gases. Water is also evaporated into atmosphere.Atmosphere which has become saturated with water precipitates its moisture when the temperature lowers. This phenomenon is termed rainfall. The moisture falls to the earth and finds its way into a number of reservoirs.provided by nature. Vast depressions in the earth are filled with water through the medium of natural water sources such as rivers lakes, etc. over the earth's surface. These bodies of water are classified as inland lakes and are excellent sources of water. Sometimes the rainfall finds its way into the soil and forms water bodies at various levels because of the impervious nature of the undersoil. Often a water body deep in the soil consists of a sand or gravel stratum which connects or empties into the basin of an inland lake and provides a splendid source of water supply through the medium of a drilled well. Man uses water for domestic and sanitary purposes and returns it to the source through sewage disposal system. Industry likewise replaces water diverted to its use. Hence the cycle is completed but it is of prime importance that the supply be protected against pollution, for if it fouls no one can predict how disastrous may be the results. An adequate supply of pure, wholesome and palatable water is essential to the maintenance of high standards of health and to provide the convenience modern society demands. In some localities water is available in unlimited quantities and converting it to use is not a difficult problem. This is especially true of towns situated on large inland lakes or rivers. On the other hand there are cities where geographical location requires elaborate systems of water supply, and to provide a satisfactory supply of water in these localities becomes a large engineering task. The importance of a sufficient supply of water for domestic and industrial purpose has long been a deciding factor in the location of cities. The earliest settlers realized this need and took advantage of natural water sources by establishing colonies in close proximity to them. Water may be taken from any sources of water for human consumption after it has undergone a preliminary treatment to assure its purity. As man's communities grew in population, the demand for water increased and the need for protection of the source of water supply against the possibility of contamination became evident. Progress and civilization have called for elaborate and various systems and methods of water treatment.

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History of water supply

History of Water Supply

From the History of Water Supply

Water is power not only in the hydraulic sense, but in relation to progress and culture: campaigns as well as fortresses have been lost, projects rendered impracticable and communities have decayed for want of water.Nature has provided prototypes for most of man's devices and, just as the streams and rivers anticipated water distribution systems, so tanks, cisterns and reservoirs have their natural counterparts in water holes and natural pools. Long after man had found ways and means to organize water supplies, find them where they were hidden and lead

them to where he wanted them, streams and pools in their natural state have served as communal water supplies, even in more or less civilized Europe. The 17th century marks the beginning of the new order in communal organization and in relation to water supply, the beginning of large-scale schemes. All through London's history until modern times, the question of water supply continued to be a problem. In the 18th century even with the appearance of larger water companies the water supply was far from being satisfactory. It was a usual practice at the time to lay on water for two hours every second day. Water drawn from the river Thames was in a state that was offensive to the sight as the intake was found to be only three yards from the outlet of a great sewer. As a mutter fact it took 2 outbreaks of cholera to pass a Bill for an im¬proved water supply in the middle of the 19th century. In spite of the progress made in the field of water supply in many countries, there is much to be done yet. In Asia, Africa, Central and South America outside the great cities, methods are primitive as ever they were; village ponds

are.still used in Africa and Asia for drinking, washing and bathing and as watering places for cattle, in Madagascar in recent years people have had to carry their water bottles several miles and, as some of them can only do the journey twice a week, they have trained themselves to do with the minimum of water, drinking only on alternate days and never washing during a drought. In Japan, running water is still a luxury, even in the great cities: the average household have to carry water from a central source, while the villages rely on springs and streams. The speedy industrialization of the Soviet Union has also made the problem of water very acute. The situation in this country would have been much worse were it not for a number of important measures undertaken by the Soviet Government immediately after the Great October Socialist Revolution. Our water resources Were protected by the Decree on Forest signed by Lenin in May 1918. At present the requirements of water supply in Moscow both for the people and industry are fully met by several water treatment stations. In our capital water consumption per capita is very high, namely, it is more than 500 litres per day.Some projects of new water treatment stations are being considered to satisfy the growing needs of water in our capital.

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All year air conditioning ventilation

All Year Air Conditioning, Ventilation, Gas Supply

All Year Air Conditioning, Ventilation, Gas Supply

Air conditioning implies the control of temperature,humidity, purity and motion of the air in an enclosure. In our modern world of science and highly developed technology air conditioning is of great significance for industrial processes as well as for human comfort. Air conditioning for human comfort is employed in both large and small installations, such as theatres, office buildings, department stores, residences, airplanes, railways, cars and submarines. All-year air-conditioning systems must provide means for performing all the processes required for winter and summer air conditioning. The basic pieces of equipment are the filters, preheat coils, humidifiers, dehumidifiers, reheat coils, additional cooling coils, fans and controls. The control of air purity can be achieved in various degrees. As a minimum control some sort of filtering must be done near the entrance of the air-conditioning system. Possibly the most efficient filtering device is the electrostatic precipitator. In order to establish the size and operational requirements of an air-conditioning system, the maximum probable heating and co-demands have to be calculated. The maximum probable heating demand is usually for winter air conditioning and it involves heating and humidifying. The maximum probable cooling demand is generally for summer applications and requires cooling and dehumidifying.As far as ventilation is concerned the modern theory to this effect can be summed up in the statement that for places of general assembly the purpose of ventilation is to carry away excess heat and odours and that normally 10 cu. ft per minute of outside air per person is sufficient to accomplish this objective. In buildings such as homes, the leakage of air through cracks in doors and windows is usually sufficient to meet this requirement. Although ventilation was formerly concerned with the supply of fresh air to and the removal of hot and contaminated air from the space it gradually came to be associated with cleaning of air. Industrial buildings often present special problems in ventilation. There are certain industrial processes that are accompanied by the production of air-born dust, fumes, toxic vapours and gases which are hazardous to the health of workers.Another indispensable part of modern amenities is gas supply. It has come now to be of a very wide use. With an in tensive exploration of finding natural gas it has gradually replaced the manufacture in its utilization. At the present time natural gas is put to large-scale economic use. The principal utilization of natural gas is as a clean, convenient, economical source of heat. In homes it is used for cooking, waterheating, refrigeration for food as well as for space heating.

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Panel heating