Treatment technology of printing and dyeing wastewater

1、 Sand filtration + UF + Ro / NF treatment process

After pretreatment, the printing and dyeing wastewater will reduce the CODCr, suspended solids and turbidity in the wastewater, and enter the ultrafiltration treatment system to remove the smaller suspended solids, turbidity and chroma before entering the subsequent Ro / NF treatment system to intercept the pollutants in the wastewater, separate and concentrate the pollutants, so as to make the effluent meet the quality requirements of production reuse water.

2、 Pretreatment + Ro / NF treatment process

1. The printing and dyeing wastewater is treated by biochemical or physicochemical traditional process, and the effluent is discharged through the secondary sedimentation tank (the effluent quality is good), and the suspended solids and CODCr in the wastewater are effectively treated. The supernatant of secondary sedimentation tank can further remove suspended solids and turbidity in wastewater through filter or high-efficiency sedimentation technology, so that the effluent SDI can meet the requirements of < 5. After entering the subsequent Ro / NF treatment system, the pollutants in the wastewater are intercepted, and the pollutants are separated and concentrated, so that the effluent meets the quality requirements of production reuse water.

Pretreatment system: the system uses sand filter, fast filter or high efficiency sedimentation technology to further remove suspended solids and turbidity in wastewater, so that the effluent SDI can meet the requirements of < 5.

3、 MCR / MBR + Ro / NF treatment process

After the printing and dyeing wastewater is treated by traditional process or low concentration wastewater is not treated, the concentration of organic pollutants and suspended solids in the wastewater is high. Through MCR or MBR treatment technology, the organic pollutants and suspended solids in the wastewater are reduced, and enter the subsequent Ro / NF treatment system to retain the pollutants in the wastewater, so that the effluent can meet the quality requirements of reuse water.

Membrane bioreactor process (MBR) is a new wastewater treatment technology combining membrane separation technology with biotechnology. The membrane separation equipment is used to intercept and retain the activated sludge and macromolecular organic substances in the biochemical reaction tank to separate the clean water, so as to realize the synchronous biochemical reaction and the separation of clean water, and the secondary sedimentation tank is omitted.

MBR is a compact and simple unit structure, especially suitable for the treatment of printing and dyeing wastewater with complex components and high concentration of pollutants.