How to detect and remove harmful gases from tube-well

摘要

The excessive withdrawl of ground water has resulted in a sharp decline of water table level. As a result, the ground water has gone beyond the suction/ lift range of the centrifugal pumps. This has forced the farmers to deepen the exiting pits and digging of new pits for installing centrifugal pumps. Accumulation of harmful gases has been found in tube well pits after the onset of monsoon. When a person into pits for repair and maintenance of pump he feels difficulty in breathing and become unconscious after few minutes and may dies if he remains in pit for longer time. The analyses of air samples show the presence of more carbon dioxide, increase in nitrogen and decrease in oxygen contents. Heavy rains and continuous flooding of rice fields result in formation of sheet of water over the large areas thus preventing the replenishment of oxygen and escape of carbon dioxide gases in soil-air by gaseous exchange.