What are the treatment processes of textile wastewater?

Textile printing and dyeing industry is a major industrial sewage discharge, sewage mainly contains textile fibers on the dirt, grease, salts and processing process additional various slurry, dye, surfactants, additives, acid and alkali.  Wastewater is characterized by high concentration of organic matter, complex composition, deep color and variable, pH change, water quality change, but also has high COD, biochemical poor characteristics, is difficult to treat industrial wastewater.

For the printing and dyeing wastewater coagulation treatment, the key lies in the selection of appropriate flocculant, conventional flocculant for printing and dyeing wastewater treatment is mainly in the early stage is polyaluminum chloride, aluminum sulfate, ferric sulfate, ferric chloride,  In the later stage, cationic polyacrylamide is used. These flocculants have obvious effects in the treatment of some insoluble dye wastewater, such as dispersive dyes, reducing dyes, vulcanized dyes,COD and chroma removal rates are very high.  

1, in the textile industry, polyacrylamide flocculant as fabric post-processing sizing agent, finishing agent, can generate compliant, wrinkle, mold resistant protective layer.  

2. Flocculant as post-treatment agent can prevent static electricity and flame retardant of fabric.  

3, when used as printing and dyeing auxiliaries, can make the product adhesion fastness, high brightness, can also be used as bleaching non-silicon polymer stabilizer.  

4, for the printing and dyeing textile industry sewage discharge has a high efficiency purification role.

In the aspect of treatment technology, in recent years, the textile printing and dyeing industry sewage treatment using biological treatment technology, has achieved good treatment results.  

1. Anaerobic biological treatment of textile factory printing and dyeing wastewater:  

The anaerobic decomposition of organic matter includes two stages: acidic fermentation and alkaline fermentation.  In the acid fermentation stage, the organic matter in the printing and dyeing wastewater of textile factories is decomposed into simple organic matter under the action of acid-producing bacteria. In the alkaline fermentation stage, the pH value gradually rises due to the neutralization effect of NH3 on organic acids, and the methanogens begin to act and decompose the organic acids and alcohols of the decomposition products in the previous stage into methane and carbon dioxide.  

2, aerobic biological treatment of textile factory printing and dyeing wastewater:  

Textile printing and dyeing wastewater treatment in the state of dissolved organic matter in the aerobic decomposition process, solid and colloidal organic matter was first adsorbed by bacteria, and under the action of bacteria secreted enzymes, hydrolysis into soluble substances, and infiltrate into the bacterial cells.  Under the action of internal enzymes, part of the dissolved organic matter entering the cell is oxidized and decomposed into simple inorganic matter, and at the same time, energy is released.  

Generally speaking, the combined process of anaerobic and aerobic treatment of printing and dyeing wastewater in textile factories can save energy and reduce consumption, and the effect is better.