The printing and dyeing wastewater of printing and dyeing Industrial Park mainly accepts the wastewater that meets the indirect standard requirements in Table 2 of GB 4287-2012 "Discharge Standard of Water Pollutants in Textile Dyeing and Finishing Industry" after pretreatment by various printing and dyeing enterprises in the park.

Process design

Process design introduction

Printing and dyeing wastewater first enters the mechanical grille to remove most of the suspended matter and enters the regulating 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 from the primary clarifier flows into the hydrolysis tank and the anoxic 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.

In the anoxic pool denitrifying bacteria will bring in the internal reflux nitrate through biological denitrification, into the atmosphere into nitrogen, so as to achieve the purpose of nitrogen removal;

In the aerobic tank, the nitrifying bacteria will convert ammonia nitrogen and ammonia nitrogen from organic nitrogen into nitrate through biological nitrification. In the aerobic tank, most of the pollutants are degraded and the sewage quality is further purified through the role of aerobic microorganisms. The effluent from the activated sludge tank mixed liquor outlet flows into the secondary clarifier, where the sludge and water are separated, 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.

Add ozone to the ozone oxidation tank, through ozone oxidation, further remove chrominance, decompose difficult to degrade macromolecular organic matter, improve biodegradability.

The aerated biological filter is filled with particle filler with high specific surface area, which is a reactor integrating biofilm method and activated sludge method. The biological aerated filter has the function of biooxidation degradation and filtration at the same time, so high effluent quality can be obtained.

The filter cloth filter tank is filled with a filter cloth, which is filtered through the filter cloth to intercept the suspended matter floating in the biological aeration filter tank to ensure the quality of the effluent. After passing through the filter cloth filter, the waste water is discharged directly up to the standard.