The flocculation process, which follows coagulation, usually consists of slow gentle stirring. During flocculation, as the particles come into contact with each other, they cling together to form larger particles which can be removed by settlement or filtration. Excessive chemical salts in water make it unpalatable. Desalination by distillation produces water without chemical salts and various methods can be used at household level, for example to treat seawater. Desalination is also effective in removing other chemicals like fluoride, arsenic and iron.
Disinfection is a way of ensuring that drinking water is free from pathogens.
The effectiveness of chemical and solar disinfection, and to a lesser extent boiling, is reduced by the presence of organic matter and suspended solids. Disinfection by boiling. A typical recommendation for disinfecting water by boiling is to bring the water to a rolling boil for 10-12 minutes. Chlorination is the most widely used method for disinfecting drinking water. Iodine is another excellent chemical disinfectant that is sometimes used.