Regulating And Mechanism Of Fe~0/GO To Treatment Of High Concentration Organic Wastewater With Anaerobic Biological Technology

Anaerobic biogas fermentation system is a common technique for treating high concentration organic wastewater which has the characteristics of high load,low energy consumption and energy production.However,it is urgent to solve the problems of long growth generation time of anaerobic microorganisms,long hydraulic retention time,sensitivity of microorganisms to poisons and environmental changes,and low efficiency of wastewater treatment.In this study,Fe⁰/GO was used to enhance the effect of anaerobic biological treatment of high-concentration organic wastewater,so as to provide more economic and effective technical support and theoretical reference for the treatment technology of high-concentration organic wastewater.Firstly,through the anaerobic degradation experiment of high concentration organic wastewater,the appropriate ratio and dosage of Fe⁰/GO were determined,which were 5:1 and 1.2g/L,respectively.Then the regulation of Fe⁰/GO on anaerobic treatment of high concentration organic wastewater was studied,and Fe⁰ group,GO group and blank group were used as the control.The results showed that the removal rate and gas yield of COD_Cr in the Fe⁰/GO system?91.8%and 511 mL/d?were significantly higher than those in the 3 control groups.The degradation kinetics results showed that the degradation rate constant k of Fe⁰/GO system was 0.2113 h^-1,while that of blank,GO and Fe⁰ systems were 0.1743 h^-1,0.1836 h^-1 and 0.1990 h^-1,respectively.Among the four systems,the Fe⁰/GO system had the lowest redox potential?ORP?,which was-355 mV.The study on volatile fatty acids?VFAs?showed that the acetic acid fermentation was the dominant one in each system.The acetic acid climax community was always the dominant acid producing fermentation community of the anaerobic system during the whole experiment,and it had certain stability,which provided sufficient substrates for methanogens.The results of total VFAs showed that adding Fe⁰/GO could effectively accelerate the acid production process and promote the anaerobic treatment of high concentration organic wastewater,and the flocculation performance of activated sludge was better than that of the three control groups.High-throughput sequencing technology was used to study the stable co-metabolizing bacteria in each reactor.The results showed that the relative percentage and diversity of anaerobic dominant bacteria in Fe⁰/GO system were high,and the co-metabolizing bacteria with stable hydrolytic fermentation,acid-producing bacteria and methane-producing bacteria were formed.Effect of Fe⁰/GO on electron transfer research had shown that the electrical conductivity of Fe⁰/GO system had the highest conductivity and the lowest impedance,which were 13.8 mS·cm^-1 and 129.9?,respectively.Through the kinetic analysis of ETS activity,it was found that the TTC-ETS activity(₈))of Fe⁰/GO system was up to 500 mg TF·?g TSS·h?^-1,significantly higher than that of the other three control groups.The₈)of blank,GO and Fe⁰ systems was 178.6 mg TF·?g TSS·h?^-1,188.7 mg TF·?g TSS·h?^-1 and 384.6 mg TF·?g TSS·h?^-1,respectively.The addition of Fe⁰/GO significantly accelerated the electron transfer rate in the system and accelerated the degradation of organic matter.Finally,the impact resistance of each anaerobic system to pH and temperature in the presence of Fe⁰/GO was studied.The results showed that Fe⁰/GO system had the strongest impact resistance to pH and temperature,and could quickly recover the treatment effect,sludge activity and physicochemical characteristics.