| Focusing on the problems of insufficient carbon source for denitrification from sludge digestion supernatant,developed a single-stage bio-electrolysis coupling multi-path denitrification technology for sludge digestion supernatant.The research focused on sequencing batch and continuous flow bio-electrolytic coupling systems,and explored the influence of electrode materials,microbial growth methods,and operating conditions on the construction of bio-electrolytic coupling systems,16S r RNA Amplicom high-throughput sequencing was used to analyze the microbial population in the constructed system reveals the microbial action mechanism of the single-stage biological-electrolytic coupling system for denitrification;the effects of nitrogen loading and C/N ratio on the efficacy of the bio-electrolytic coupled system were investigated,quantitative analysis of the system’s multi-path denitrification;on this basis,the biological-electrolysis coupled system’s treatment efficiency of the actual sludge digestion liquid is explored,and the system is explored using 3D-EEM and FRI analysis.Degradation law of refractory organic matter.The main conclusions of the study were as follows:Electrode materials,microbial growth methods,and operating conditions had significant effects on the construction of a sequencing batch bio-electrolysis coupling system for high ammonia nitrogen wastewater.The reactor was successfully constructed after 21 days of operation of the biological denitrification system.The TN removal rate of the three-cathode bio-electrolysis coupling system with iron rods as the anode reached90.8±0.7%,and its denitrification efficiency is better than the system with carbon rod anode and no electrolysis.The removal rate increased by 5.0%and 6.0%respectively;the denitrification efficiency of biofilm SBBR-electrolysis coupling system is better than activated sludge SBR-The electrolytic coupling system has a high TN removal rate of8.6%;the denitrification effect of placing anoxic electrolysis before the aerobic section is better than placing anoxic electrolysis after the aerobic section,and the TN removal rate is increased by 3.3%.The results of 16S r RNA Amplicom high-throughput sequencing showed that the nitrifying bacteria in the system are AOB Nitrosomonas;the denitrifying bacteria in the system are mainly endogenous denitrifying bacteria Thauera,aerobic denitrifying bacteria Acinetobacte,Pseudofulvimonas,autotrophic denitrifying bacteria Hydrogenophaga and the heterotrophic denitrifying bacteria Ottowia.The system achieves denitrification through the synergistic action of short-cut nitrification and multi-path denitrification（aerobic denitrification,endogenous denitrification,autotrophic denitrification,heterotrophic denitrification）.The continuous flow biological-electrolysis coupling system for high ammonia nitrogen wastewater was successfully constructed after 19 days of operation.,The TN removal rate was 82.9±0.7%.The results of 16S r RNA Amplicom high-throughput sequencing showed that the main nitrifying functional bacteria in the system are Nitrosomonas;the denitrifying functional bacteria in the system included endogenous denitrifying bacteria Thauera,Zoogloea,Bdellovibrio,and the aerobic denitrifying bacteria are Acinetobacte,Pseudofulvimonas,Gemmatimonas,autotrophic denitrifying bacteria Hydrogenophaga,heterotrophic denitrifying bacteria Ottowia,the system is realized through the synergistic effect of short-range nitrification and multi-path denitrification（aerobic denitrification,endogenous denitrification,autotrophic denitrification,heterotrophic denitrification）.The C/N ratio had a significant effect on the denitrification efficiency of the sequencing batch biological-electrolysis coupling system for high ammonia nitrogen wastewater.When the C/N ratio is 3,2,1,and 0.5,the TN removal rate is 94.2±0.5%,87.3±0.5%,74.0±0.6%,respectively.,the bio-electrolysis coupling system with a C/N ratio of 0.5 maintained a high TN removal rate,and the sharing rates of heterotrophic denitrification and autotrophic denitrification in the system were 37.4%and 62.6%,respectively.When the temperature is 30±3℃,C/N ratio is 0.35～0.46,nitrogen load is0.10～0.13kg N/（m3·d）,and the operating conditions is instantaneous inflow-hypoxia 2h-electrolysis 4h-aeration 17.75h-effluent precipitation 0.25h,the effluent NH4+-N,TN and COD were 16.8±1.7,42.5±3.8 and 53.8±6.7 mg/L,respectively,and the removal rates of NH4+-N,TN and COD were 96.6±0.3%,91.8±0.8%and 69.5±4.2%,respectively.3D-EEM and FRI analysis showed that the total fluorescence intensity of the influent of the sludge digestion solution was 131.87×107,AU-nm2,and the total fluorescence intensity of the treated effluent was reduced by 38.1%;the total accumulation of refractory organic matter in the effluent in areasⅠandⅣ～ⅦThe fluorescence intensity is 62.20×107,AU-nm2,which is 33.2%lower than the influent water.The biofilm-electrolysis coupling system has a certain ability to remove refractory substances through electric flocculation. |
