Knitting fabric printing and dyeing wastewater mainly includes:

Boiling wastewater, bleaching wastewater, dyeing wastewater, washing wastewater, etc.

Boiling wastewater:

The wastewater is alkaline. The wastewater mainly contains cellulose, fruit acid, wax, oil, alkali, scouring agent, etc., the amount of water is large, the concentration of pollutants is high.

Bleaching wastewater:

Wastewater mainly contains residual bleach and so on. The amount of water is larger and the concentration of pollutants is higher.

Dyeing wastewater:

Wastewater mainly contains dyes, sodium sulfate, fixing agents, auxiliaries and so on. The general chroma is high, the amount of water is large, the concentration of pollutants is high, and the biodegradability is poor.

Washing wastewater:

Wastewater mainly contains acetic acid, soap detergent, softener, fixing agent and so on. Generally neutral, low chroma, large amount of water, low concentration of pollutants.

Process design

Process design introduction

The comprehensive wastewater includes boiling wastewater, bleaching wastewater, dyeing wastewater, washing wastewater, etc.

The comprehensive wastewater first enters the mechanical grille to remove most of the suspended matter and enters the comprehensive adjustment tank. Then it is lifted to the initial settling reaction tank by the lifting pump, and the pH value is fine-tuned. At the same time, chemicals are added to make SS and some colored substances in the sewage undergo physicochemical reaction and flocculation precipitation, and most of them are removed in the air flotation tank. The supernatant of the initial sedimentation tank enters the hydrolysis tank and the aerobic tank. The supernatant from the primary sedimentation tank flows into the acidification tank and the aerobic tank. The macromolecular organic matter which is difficult to biodegrade in the wastewater is further decomposed into small molecular organic matter pollutants which are easy to degrade through the hydrolysis acidification of the hydrolysis tank, and the biodegradability is improved. Through the action of aerobic microorganisms in the aerobic tank, most of the pollutants are degraded and the sewage quality is further purified. After the sludge water is separated in the secondary sedimentation tank, the supernatant flows to the mixed sedimentation tank by itself. Part of the sludge is returned to the activated sludge tank through the sludge return pump, and the remaining sludge is discharged to the sludge thickening tank. Coagulant is added to the reaction area of the mixed sedimentation tank, the effluent enters the mixed sedimentation tank after stirring reaction, and the pollutants in the effluent are further reduced after coagulation reaction. The supernatant of the mixed sedimentation tank flows into the outlet tank for metering and discharge, and the sludge is discharged into the sludge thickening tank.