Currently, there is no unified classification of wastewater, but there are atmospheric water, urban wastewater, industrial wastewater and agricultural wastewater
The methods of purification of polluted waters are diverse and are predetermined by the physico-chemical, physical, chemical and microbiological indicators of the impurities contained in them.
Most often, about 85% of water is returned to the technological process and about 5% is discharged into surface sources, the rest of the water goes to losses – 10%.
As a rule, wastewater treatment systems are built on the basis of using a set of purification methods. The determining criterion for choosing a method of water purification is its further use. The desire of specialists to maximally transfer enterprises to a closed cycle of water use leads to a deterioration in the quality of water that is used for household purposes.
The efficiency and reliability of any cleaning device is determined by the range of values of the impurity concentration and waste water flow.
The most common classification of cleaning methods is the following:
- methods of mechanical cleaning – from suspended substances in the form of suspensions and emulsions;
- physico-chemical methods of purification - from colloidal dispersed and truly dissolved impurities;
- chemical methods of purification-from truly dissolved impurities;
- biological methods of purification - from organic substances.