Tuesday, May 29, 2018

Source of Water in Textile | Impurities of Water and Their Significance

Textiles and Water Use:
In a textile processing plant, water is a vital raw material not only for the boilers supplying steam for heating and drying purpose, but also for all the wet processes such as scouring, bleaching, dyeing, printing and finishing. The success of these processes largely depends on the quality of the water being used. Generally, two qualities of water are to be maintained separately-very poor quality for feeding to the boiler, and moderately pure quality for processing purpose.
Using water in textile and apparel industry
Fig: Using water in textile and apparel industry
Source of Water in Textile and Apparel industry:
Water with a high degree of purity is rarely obtained from natural sources. The mineral constituents differ in amount and relative proportions, depending on the source. Supplies of water may be broadly classified into three groups:

1. Surface Water:
It is mainly accumulation of rainwater in streams, rivers and lakes. As it passes over the surface of the earth, it carries organic matters of varying stages of decomposition, a part of which is converted into nitrates by nitrifying bacteria. It also dissolves various mineral matters, depending on the nature of the soil or rock coming in contact, or may be turbid due to their suspensions. Generally, it contains sulphates and chlorides as well as bicarbonates of calcium and magnesium. Decaying vegetables may distinctly discolor surface water.

2. Subsoil Water:
Water, collected from shallow wells or surface springs, is actually surface water percolated a small distance through the soil or rock. It is generally free from suspension, as water is being filtered by the passage through soil. It, however, contains dissolved organic matters. Subsoil water is often rich in carbon di0xide arising from metabolism of vegetable life. It converts insoluble calcium content of subsoil waters may vary significantly.

3. Deep Well Water:
Water from deep wells or deep tune-wells is collected from a considerable depth below the ground, and such water has percolated through several layers of ground. Such water is generally free from organic matters due to filtration and bacterial action. The mineral content, however, may be very high because of prolonged contact with several layers of rocks and soil. It may contain sodium bicarbonate in addition to the bicarbonates and other salts of calcium, magnesium and iron.

Different Impurities of Water:
Various impurities commonly present in water are grouped as mentioned in the below:
  1. Suspended solids,
  2. Dissolved mineral salts,
  3. Organic and coloring matters,
  4. Dissolved gases,
  5. Bacterial and other micro-organisms.

The impurities affect the following characteristics of water and are, therefore, assesses regularly for the feed water in textile industry.
  • Turbidity and color,
  • Dissolved mineral salts,
  • Dissolved gases,
  • Alkalinity,
  • Water hardness.