Industries that require wastewater treatment are: chemical, paper, printing and dyeing, leather, food processing, breeding plants, medical treatment, slaughtering, pharmaceuticals, new villa complexes, coal mines, steel, oil fields, hotels.
Modern sewage treatment technology can be divided into primary, secondary and tertiary treatment according to the degree of treatment. Generally, the degree of sewage treatment is determined according to the water quality status and the whereabouts of the treated water.
It mainly removes suspended solid pollutants in sewage. Most of the physical treatment methods can only meet the requirements of primary treatment. After primary treatment, BOD can be removed by about 30%, which can not reach the discharge standard. The primary treatment belongs to the pretreatment of the secondary treatment.
It mainly removes colloidal and dissolved organic pollutants (BOD, COD substances) in sewage, and the removal rate can reach more than 90%, making organic ...