Study On Coupling Of Photocatalytic And Aerobic Biological Process For Advanced Treatment Of Pigment Production Wastewater

A large amount of wastewater is generated during the production of pigments.Because the wastewater contains some organic substances that are difficult to biodegrade,the wastewater is still difficult to meet national discharge standards after anaerobic/aerobic（A/O）microorganism treatment.In this study,a S/TiO₂photocatalyst was prepared by a sol-gel method,and the biodegradability of the biological treatment effluent of pigment production wastewater was improved by photocatalytic pretreatment,and the relationship between the chroma and biodegradability of pigment wastewater was studied.The photocatalytic effluent was then returned to the aerobic bioreactor,and the wastewater was further treated through the biological degradation of the aerobic microorganisms.The structure and changes of the microbial community before and after the reactor operation were analyzed,so that the pigment wastewater reached the discharge standard,which reduced the amount of industrial wastewater.Costs of gradual drainage of wastewater from the sewage treatment plant in the park.In this study,a S/TiO₂ photocatalyst was prepared by a sol-gel method at a calcination temperature of 300 degrees.The prepared catalyst was characterized by spectroscopy（DRS）.The results showed that the catalyst exhibited high crystallinity and uniform morphology,and the crystal structure was pure anatase crystal.The form of SO₄^2-is fixed on its surface.Compared with commercial titanium dioxide P25,S/TiO₂ catalyst has higher photocatalytic efficiency under simulated sunlight.The best parameters for photocatalytic oxidative degradation of pigment wastewater were determined by single-factor experiments.The experimental results show that the doping dose of K₂S₂O₈ is 0.50 wt%,the dosage of catalyst is 2 g/L,and the initial p H of the wastewater is 8.3 the effect of photocatalytic oxidation degradation of pigment wastewater is the best.After 180 minutes of photocatalytic pretreatment,the COD of the wastewater decreased from 382 mg/L to 250 mg/L,and the chroma decreased from 525 to 8,while the biodegradability of the wastewater increased from 0.08 to0.34,which can be returned to aerobic organism the reactor undergoes microbial degradation,and the photocatalytic degradation experiment follows pseudo-first-order kinetics.The COD removal rate became stable after 30 days of acclimation of the inoculated sludge of the aerobic microbial reactor.After 180 days of continuous operation,the COD of the wastewater after biological reaction decreased from 258mg/L to 46 mg/L,and the COD removal rate increased to 88%,The COD of the wastewater degraded by microorganisms has dropped to<50 mg/L,and has reached the IA level in the Pollutant Discharge Standard for Municipal Wastewater Treatment Plants（GB 18918-2002）.High-throughput sequencing showed that compared with seed sludge（S0）,the abundance of bacteria that benefited from the degradation of hard-to-degrade substances was increased,such as Dokdonella（8.88%）,Defluviimonas（5.71%）,Thaauera（4.4%）and Rhodobacter（3.95%）,they are enriched in activated sludge of aerobic bioreactor（S1）.