1 usage of water, 3 water supply and demineralisation

What is the role of water during the washing process?
1. solvent for detergents only
2. energy transfer to textiles
3. transportation of detergents to textiles and removal of soil from textiles
What are the basic requirements of water for laundries?
1. soft (below 4 od), Fe ions <0.01 mg/l, Mn ions <0.05 mg/l
2. no Fe ions, no Mn ions
3. no Fe ions, no Mn ions, no heavy metals
What does the water hardness mean?
1. presence of alkaline earth ions
2. presence of heavy metals
3. presence of organic compound
Temporary hardness of water is caused by:
1. Ca(Mg)-sulphates, chlorine and nitrate
2. Ca(Mg)-hydrogen carbonates
3. Ca(Mg)-hydrogen carbonates, sulphur, chlorine, nitrate
Permanent hardness of water is caused by
1. Ca (Mg)-hydrogen carbonates
2. Ca(Mg)-sulphates, -chlorides, -nitrates
3. Ca(Mg)-hydrogen carbonates, -sulphates, -chlorides, -nitrates
Reasons of inorganic incrustation are?
1. precipitation of Ca(Mg)- sulphates, -chlorides, -nitrates
2. precipitation of Ca(Mg)- carbonates
3. precipitation of Ca(Mg)- hydrogen carbonates
Inorganic incrustation can cause
1. only residues on laundry (greying, high ash content, mechanical fibre damage)
2. only sediment on tube walls and electrical heating coils
3. both residues on laundry and sediment on tube walls and electrical heating coil
What are the consequences of reaction of soaps with Ca(Mg) ions?
1. insoluble soap salts formation and reduced concentration of wash-active substances in the wash liquor
2. greying of the laundry
3. build-up a hydrophobic film on the fibre surface
What are sources for heavy metals in laundries?
1. water
2. corrosion of pipes and tanks only
3. textile goods + corrosion of pipes and tanks
What are the consequences of heavy metals` presence for washing and bleaching processes?
1. deposition on textiles
2. yellowing of textiles and depolymerization of cellulose
3. Catalytic decomposition of peroxides during bleaching
Microbiological requirements for the technological water?
1. requirements shall meet the limits of drinking water
2. no requirements are fixed
3. the limits of drinking water can be exceeded max. 2x
What will be removed by heating?
1. temporary (carbonate) hardness
2. permanent (non-carbonate) hardness
3. Mn and Fe content
Unit of water hardness is
1. mmol CaO
2. mmol CaSO4
3. mmol FeO
Which degrees are used as units of water hardness
1. German degree, English degree or French degree
2. American degree or French degree
3. Italian degree, English degree or French degree
The best used unit of water hardness in Europe is
1. English degree
2. German degree
3. French degree
Incrustation on textiles are the most often caused by
1. hard water
2. wrong pH value of the water
3. too fast cooling of the wash liquor

1 usage of water, 3 water supply and demineralisation

This chapter is about water supply and demineralisation. You already learned somtething about the water consumption in different kind of washing machines. Now the view is focussed on the quality of the water.