Method and apparatus for reducing secondary pollution and recovering water from dyeing and finishing wastewater for reuse

摘要

A method and an apparatus for reducing secondary pollution and recovery of water from dyeing and finishing wastewater. The apparatus comprises: a shunt control unit 10 that splits wastewater into highly and lowly polluted wastewater depending on whether the COD level in the wastewater is higher or lower than 600 mg/L or according to the amount of total dissolved solids (TDS); a sieving module 11 having a de-silting and degreasing unit 110 and an undersize sieving unit 110; a pH value adjustment module 12 having a blending unit 120 and a pH value adjustment unit 121; a coagulation and despumation module 13 having a coagulation unit 130 and despumation unit 131; a cooling unit 14; a microorganism decomposition module 15 having a microorganism decomposition unit 150 and a microorganism removal unit 151; an ion filtration unit 16 and an evaporation unit 17. Grease is removed using either gravitational precipitation or centrifugal force. The pH unit adjusts the pH of the wastewater to a level of 6-8. Suspended solids are agglutinated using an electrolytic or chemical coagulant. Pollutants are decomposed using oxygen uptake and anaerobic digestion. Ions are removed by reverse osmosis or electrodialysis.