Adsorption, precipitation, filtration, distillation and sterilization.
Adsorption: Alum and activated carbon are commonly used. Alum dissolves in water to form gel, which absorbs suspended solids in water. Activated carbon can not only adsorb suspended solids in water, but also adsorb odorous substances and pigments in water.
Sedimentation: Suspended substances in water are adsorbed separately to form dense particles, thus precipitating impurities.
Filtration: remove insoluble impurities in water.
Distillation: a method of removing soluble impurities.
Sterilization: common disinfectants: bleaching powder, chlorine gas, new disinfectant chlorine dioxide.
Among adsorption, precipitation, filtration and distillation, distillation has a high degree of purification.
Comprehensive application, according to the order of adsorption, precipitation, filtration and distillation, the purification effect is good.
Tap water purification steps:
① Take water from the reservoir.
(2) Flocculants (mainly alum) are added to make the suspended small-particle impurities adsorbed and condensed.
(3) precipitating and separating in a reaction sedimentation tank to clarify water.
(4) introducing clear water flowing out of the sedimentation tank into the filtration tank to further remove insoluble impurities.
⑤ Introduce water into the activated carbon adsorption tank to remove odor and residual insoluble impurities with smaller particles.
⑥ Bacterial disinfection (commonly used chlorine gas). It is a process of chemical change, because the process of removing germs is the process of turning germs into other substances.
⑦ Disinfection water is clean and drinkable tap water, which is supplied to users through a water distribution pump, but the water still contains some impurities that can be dissolved in water, so it is still a mixture.