Characteristics Of Printing And Dyeing Wastewater

Characteristics of printing and dyeing wastewater

Textile printing and dyeing industry is a large industrial sewage discharge, sewage mainly contains textile fibers on the dirt, grease, salt and processing of various additional slurry, dyes, surfactants, additives, acid and alkali, etc..

Wastewater is characterized by high concentration of organic matter, complex composition, deep color and variable, large pH change, large water and water quality change, it is difficult to treat industrial wastewater.

With the development of chemical fiber fabrics, the rise of emulation silk and improvement of printing and dyeing finishing, the PVA slurry, rayon alkaline hydrolysis, new dyes, auxiliaries and refractory organic compounds into a lot of textile printing and dyeing wastewater, pose serious challenges to the traditional wastewater treatment process, the COD concentration also increased from the original hundreds of milligrams per liter to 3000 ~ 5000 mg/l.

Pulp dyeing waste water high chromaticity, high COD, especially according to the foreign market developed silk, silk black, dark blue, blue, dark such as printing and dyeing process, the sulfur dye is widely used in printing and dyeing, printing and dyeing auxiliaries such as sodium sulfide, wastewater contains a large number of sulfide, therefore, this kind of wastewater must be dosing preprocessing, and then serial processing, can stable discharging standard.

Wastewater containing dye bleaching, pulp, surface active agent and other auxiliaries, this kind of waste water, the density and chromaticity are low, if simply using physico-chemical treatment, the effluent is between 100 ~ 200 mg/l, color also can to meet emissions requirements, but to increase pollution, high cost of sludge treatment, easy to cause secondary pollution, in the case of a strict environmental protection, biochemical treatment system should be considered, and the conventional enhanced biological treatment process can meet the requirements.