Water treatment refers to purify polluted industry water or river water through series
water treatment equipment to correspond with national water quality standard. As society
producing and life are relevant to the water, so the water treatment is widely used and
composes enormous industrial applications.
Waste water treatment is generally including following three grades treatment:
Primary treatment:remove the stone, gravel, fat, ferric ion, manganese ion and oil etc.
content in polluted water by mechanical treatment, such as retainer, sediment or air
Secondary treatment means biological treatment, the degradation and conversion of
pollutant under the action of microorganism.
Tertiary treatment means high treatment of sewage, it includes nutrient removing and
adopts add chlorine, ultraviolet radiation or ozone technology to sterilize sewage.
General method of water treatment has biochemical process, such as activated sludge
process, fixed biofilm processes and combined biological processes etc; physical-chemical processes, for example, granular media filtration, activated carbon adsorption,
chemical precipitation, membrane processes etc. natural treatment, for example, stabilization
ponds, aerated or facultative lagoons, constructed wetlands etc.