Water quality is an important factor affecting the quality of the linen. In the washing process, the water acts as a solvent for dissolving and separating tasks compounds in stains out of clothes.
The following factors must be considered when washing:
- Ideal for cleaning water.
- Surface tension
- Hardness of water
- Metal content in the water

1 Water "ideal" for laundry
Features "ideal" of water will bring the best washing efficiency because it helps dissolve completely and effectively promote the laundry chemicals. Characteristics of water "ideal" in the laundry cited as below:
value
Hardness less than 4-5 ° dH
pH 7.0-7.5
Iron less than 0.1 mg / l
Manganese smaller of 0.05 mg / l
The analysis of water quality input in the laundry service is very important. If water has high hardness, the use of a water softener device should automatically be considered for use.
2 Surface tension of water
Clean water with large surface tension, therefore, it would be very difficult to penetrate between the fibers and stains. Ability to penetrate between the fibers and fiber stains is very important because it will create an environment of solvent soluble chemicals and pull out stains from clothing. The greater the surface tension will affect greatly to this effect after washing.
The addition of surface-active compounds in water will help reduce the tension of water and thus increases the efficiency laundry detergent in water. Currently, the compound into a surface integral component chemicals and washing powder.
3 Hardness
Water is the most versatile type of solvent on earth, capable of a lot soluble compounds. This is one of the most amazing properties of water without any substance can be. However, due to solubility of this great, bring water to a hassle for the quality control of laundry, this problem called "hardness".
The hardness of water is sort of the presence of calcium and magnesium salts. This concentration of salt, which is considered the scale due to hardness in the water, the unit is ppm or dH (Deutsche Harte). Water hardness 1dH will contain 10 mg of CaO in 1 liter of water, 1 dH 17,848 mg CaCO3 equivalent of 1 liter of water, or 17,848 ppm.
The hardness, soft water is given in the following table dH price:
Value juices dH
- Soft water 0-6 °
- Hard water just 7-13 °
- Hard water weighs 14-20 °
Efficient washing of chemicals will be reduced when it is dissolved in water with high hardness. The reason is because the pathogens in water hardness (calcium, magnesium carbonate) reacts with surface-active substances in chemical detergent affect its ability to reduce the surface tension of water and lead to effective remove fruit stains and low solubility.
In addition, these agents reacting with chemicals, salts tend to form carbonates or sulfates precipitated on the surface of the laundry, reduce brightness and cause the phenomenon of stained, yellow and dingy . Agent hardness can reduce the effectiveness of laundry softener and sometimes the reactions are caused unpleasant odors.
In addition, activity in hard water conditions also increase operating costs due to frequent equipment sanitation to remove hard deposits in the washing machine. In the hard water conditions, water softening equipment should definitely be used to ensure quality customer laundry as well as the durability of protective equipment. Currently on the market, water softening equipment is mainly based on the method of ion exchange filtration, separation of Ca2 + and Mg2 + out of the water! The cost of investment and operation of devices is relatively high, but the review and analysis of long-term conditions of use will be found feasible by chemical savings and improve service quality laundry
4 The alkaline
Alkaline / acidic water is determined by the pH value, the value of the logarithm of the concentration of H + ions in water.
The substance is alkaline and alkali metal salts, are important in the washing because it is capable of removing dirt from fabric without rubbing, beating, excessive bleaching. Soluble salts of potassium or sodium degreasing very good, because they form emulsions and oil particles suspended in water. The particles are no longer able to cling on clothes and will follow the entire discharge out.
5 Heavy Metals
Due to the versatile nature of the solvent, water contains many metal ions, including iron and manganese are metals strong influence on the quality of laundry. When the concentration of the two ions in the high country, it will cause problems such as:
- The precipitate on the surface and causes discoloration of laundry
- Causing damage to the fabric
This is also a factor as hardness, impact greatly on the quality of the linen. The removal of these ions is relatively simple components can by using measures such as open, sand filters, reverse filtering.
To wash the stain type patches are due to iron ions in the water to be treated by the same bleaching chemical pickling special chemicals often contain 2% oxalic acid!