Experimental study on the treatment of dye wastewater by plasma coupled biotechnology

In this experiment, a gas-liquid two-phase discharge water treatment inverse device was designed independently to treat the actual workshop intermediate dye wastewater from a chemical plant. Firstly, the effects of initial concentration of wastewater, initial pH, circulation flow rate of solution, content of Fe2+, content of H2O2, and addition of tert-butanol on the organic removal rate and decolorization rate of dye wastewater treatment were investigated. The results showed that Fe2+ and tert-butanol would react with the active particles (H2O2, center dot OH) and inhibit the degradation of the dye wastewater, resulting in the decrease of both organic matter degradation rate and decolorization rate. The experimentally degraded dye wastewater mainly contained benzoic acid and its derivatives in addition to dye molecules, thus the degradation mechanism of benzoic acid was mainly analyzed. Then, the actual dye wastewater treated by low-temperature plasma was combined with the traditional biological treatment technology. The biochemical properties of the wastewater treated by low-temperature plasma technology were greatly improved, and the B/C was increased from the initial 0.17 to 0.33. The effluent after the combined biological method could meet the effluent discharge standard, and the final CODcr reached 198 mg/L, BOD5 reached 65 mg/L, and pH and chromaticity reached 6.39 and 50, respectively.