The Study On Physicochemical/Bio-enhanced Treatment Of Kitchen Waste Fermentation Wastewater

For solving the problems of high cost of membrane treatment of kitchen waste fermentation wastewater and inhibition of microbial activity by extreme ammonia nitrogen,with the goal of developing high efficiency and low cost treatment technology of kitchen waste fermentation wastewater,a vacuum thermal ammonia stripping system of kitchen waste fermentation wastewater was constructed,and the effects of temperature,pH and vacuum on the stripping efficiency of the wastewater were investigated,and the kinetics analysis was carried out.At the same time,the enhanced hydrolytic acidification technology based on zero-valent iron（ZVI）,magnetite and Fe-C micro-electrode and the enhanced hydrolytic acidification-denitrification coupling system were proposed.The construction methods and efficiency factors of enhanced hydrolytic acidification,thermophilic denitrification and enhanced hydrolytic acidification-denitrification coupling system were studied,and the microbial population structure and functional microbes of enhanced hydrolytic acidification system were explored by means of molecular biology.On this basis,an anaerobic treatment system of kitchen waste fermentation wastewater tolerant to high ammonia nitrogen based on hydrophilic methanogenic bacteria was proposed,with emphasis on the effects of sludge inoculation provenance and microbial growth mode on the construction and efficiency of the system.And the anaerobic-aerobic-coagulation combined treatment system of kitchen waste fermentation wastewater was established,the treatment efficiency of the system was investigated,the key working parameters were obtained,and the organic components of the combined system were analyzed by 3D-EEM,and the microbial population structure and functional microbes of anaerobic and aerobic biological system were studied by 16s rRNA high-throughput sequencing technology,and the microbial action mechanism of the system was explored.The main research results were as follows:Temperature and vacuum had significant effects on the ammonia stripping systematic efficiency and liquid-phase mass transfer coefficient（K_L）,while pH had no significant effect on them.When the pH and vacuum were constant,the higher the temperature was,the greater K_L was,the shorter the time required for stripping system to remove more than 90%ammonia nitrogen was,the higher the ammonia nitrogen removal rate was;and when the temperature and pH were constant,the smaller the vacuum was,the greater K_L was,the higher the ammonia nitrogen removal rate of stripping system was.ZVI,magnetite and Fe-C micro-electrode had significant effects on the efficiency and microbial population structure of hydrolysis acidification system of kitchen waste fermentation wastewater.The total degradation rates of protein and carbohydrate by ZVI,magnetite and Fe-C micro-electrolysis enhanced hydrolytic acidification system were58.16%,73.33%and 52.38%,respectively,and the magnetite group was 58.71%,15.17%and 20.95%greater than the control group,ZVI group and Fe-C micro-electrolysis group,respectively,and the average TVFAs formation rate was 56.11%,77.55%and 44.21%,respectively.The average generation rate of TVFAs increased by 57.09%compared with the control group.And the results of Illumina MiSeq 16S rRNA sequencing indicated that the dominant hydrolytic acidification microbes in ZVI reactor,magnetite reactor and Fe-C micro-electrolysis reactor were Acetomicrobium,Acinetobacter,Anaerobranca,Caldicoprobacter,Candidatus＿Microthrix,Coprothermobacter,Sporanaerobacter,Tepidimicrobium,Thermovirga,Proteiniborus and Proteiniclasticum,with the total relative abundance of 38.43%,67.50%and 32.42%.The addition of magnetite had a significant effect on the efficiency of enhanced hydrolysis acidification system of kitchen waste fermentation wastewater.When the influent TVFAs concentration was 2778.46±80.91mg/L,and when the magnetite dosage were 5g,10 g and 15g respectively,the average effluent TVFAs concentration were3649.93mg/L,4933.21mg/L and 4972.64mg/L,respectively,and the formation rate were 31.37%,77.55%and 78.97%respectively.The suitable dosage of magnetite was 10g.Nitrate load had a significant effect on the establishment and efficiency of hydrolytic acidification-denitrification coupling system for kitchen waste fermentation wastewater.When the reactors nitrate load were 0.075kg NO₃^--N/（m³·d）,0.175kg NO₃^--N/（m³·d）and 0.275kg NO₃^--N/（m³·d）,respectively,the average TVFAs formation rate of the system were 48.52%,20.90%and 9.26%,respectively,and the average removal rates of NO₃^--N were 91.43%,83.73%and 67.83%,respectively.The inoculated sludge had a significant effect on the establishment and efficiency of anaerobic ASBBR and ASBR systems in kitchen waste fermentation wastewater.The anaerobic SAOB-HM organic degradation system of kitchen waste fermentation wastewater tolerant to high ammonia nitrogen was successfully established in the anaerobic biological system by gradually increasing ammonia nitrogen.The results of Illumina Mi Seq 16S rRNA sequencing indicated that when the ammonia nitrogen concentration of the ASBR system inoculated hydrolytic acidification tank sludge were979.90mg/L,1739.48mg/L and 3140.41mg/L respectively,the dominant organic degradation microbes in the system were A55＿D21,Caldicoprobacter,Clostridium,Coprothermobacter,Desulforudis,Proteiniclasticum,Allochromatium,Anaerobaculum and SHD-231.And the dominant ammonia-nitrogen-tolerant hydrophilic methanogenic archaea in the system were Methanosarcina and Methanobacterium.The effluent COD removal rates of the anaerobic biological treatment system inoculated hydrolytic acidification tank sludge,combined fermentation system sludge and wastewater treatment plants（WWTPs）dewatering sludge were 79.93%,72.09%and 68.35%（activated sludge）respectively.The total COD removal rate of the combined anaerobic-aerobic-coagulation treatment system for kitchen waste fermentation wastewater reached 94.80%,and the effluent COD concentrations of ASBR,SBBR and coagulation process were 2708.33±394.96mg/L,828.89±94.06mg/L and 363.50±23.76mg/L,respectively,meeting the third-class standard of the Integrated Wastewater Discharge Standard（GB 8978-1996）.The corresponding COD removal rates were 61.20%,69.39%and 56.21%respectively,and the sharing rates were 61.2%,26.93%and 6.67%,respectively.The anaerobic biological process unit played a leading role,and the physicochemical effect of the coagulation unit could reduce the COD removal rate of SBBR effluent by 56.21%.The results of 3D-EEM and FRI indicated that the fluorescence intensity of regionⅢdominated by fulvic acid and regionⅤdominated by humic acid in the effluent of coagulation treatment unit decreased by 29.23%and 31.49%,respectively.The coagulation unit was effective in the removal of refractory organic matter.