Activity development of key groups of enzymes involved in municipal refuse decomposition was measured in laboratory landfill bioreactors with and without leachate recycling and inoculation for about 210 days. The resu...Activity development of key groups of enzymes involved in municipal refuse decomposition was measured in laboratory landfill bioreactors with and without leachate recycling and inoculation for about 210 days. The results showed that the enzymes (amylase, protease, cellulase, lipase and pectinase) were present in fresh refuse but at low values and positively affected by leachate recycling and refuse inoculation. The total average of cellulase activity in digesters D3 operated with leachate recycling but no inoculation, D4 and D5 operated with leachate recycling and inoculation was much higher than that in digesters D1 and D2 without leachate recycling and inoculation by 88%—127%, 117%—162% and 64%—98%. The total average of protease activity was higher in digester D4 than that in digesters D1, D2, D3 and D5 by 63%, 39%, 24% and 24%, respectively, and the positive effect of leachate recycling and inoculation on protease activity of landfilled refuse mainly was at the first two months. The total average of amylase activity was higher in digesters D3, D4 and D5 than that in digesters D1 and D2 by 83%—132%, 96%—148% and 81%—129%. During the early phase of incubation, the stimulatory effect of inoculation on lipase activity was measured, but refuse moisture was the main factor affecting lipase activity of landfilled refuse. The inoculation, initial and continuous inoculation of microorganisms existing in leachate, was the mainly stimulatory factor affecting pectinase activity of landfilled refuse.展开更多
Humic acid(HA)is a typical refractory organicmatter,so it is of great significance to investigate its effect on the performance of Anammox granular sludge.When the dosage ofHA≤50 mg/L,HA promotes the total nitrogen r...Humic acid(HA)is a typical refractory organicmatter,so it is of great significance to investigate its effect on the performance of Anammox granular sludge.When the dosage ofHA≤50 mg/L,HA promotes the total nitrogen removal rate(NRR)to 1.45 kg/(m^(3)·day).When HA was between 50 and 100 mg/L,the NRR of Anammox was stable.At this time,the adsorption of HA causes the sludge to gradually turn fromred to brown,but the activities of heme and enzymes showed that its capacitywas not affected.When HA levels reached 250 mg/L,the NRR dropped to 0.11 kg/(m^(3)·day).Moderate HA levels promoted the release of extracellular polymeric substance(EPS),but excessive HA levels lead to a decrease in EPS concentrations.HA inhibited Anammox activity,which indirectly hindered the transmission of substrate and accumulated substrate toxicity.Although HA promoted the increase of heterotrophicmicrobial abundance in Anammox system,the microbial diversity decreased gradually.With the increase of HA concentration,the abundance of Candidatus_Brocadia,the main functional microorganism of Anammox system,decreased gradually,while the abundance of Candidatus_Kuenenia increased gradually.展开更多
文摘Activity development of key groups of enzymes involved in municipal refuse decomposition was measured in laboratory landfill bioreactors with and without leachate recycling and inoculation for about 210 days. The results showed that the enzymes (amylase, protease, cellulase, lipase and pectinase) were present in fresh refuse but at low values and positively affected by leachate recycling and refuse inoculation. The total average of cellulase activity in digesters D3 operated with leachate recycling but no inoculation, D4 and D5 operated with leachate recycling and inoculation was much higher than that in digesters D1 and D2 without leachate recycling and inoculation by 88%—127%, 117%—162% and 64%—98%. The total average of protease activity was higher in digester D4 than that in digesters D1, D2, D3 and D5 by 63%, 39%, 24% and 24%, respectively, and the positive effect of leachate recycling and inoculation on protease activity of landfilled refuse mainly was at the first two months. The total average of amylase activity was higher in digesters D3, D4 and D5 than that in digesters D1 and D2 by 83%—132%, 96%—148% and 81%—129%. During the early phase of incubation, the stimulatory effect of inoculation on lipase activity was measured, but refuse moisture was the main factor affecting lipase activity of landfilled refuse. The inoculation, initial and continuous inoculation of microorganisms existing in leachate, was the mainly stimulatory factor affecting pectinase activity of landfilled refuse.
基金This work was supported by the Natural Science Foundation of China(No.51938010)the Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment(No.XTCXSZ2022-1).
文摘Humic acid(HA)is a typical refractory organicmatter,so it is of great significance to investigate its effect on the performance of Anammox granular sludge.When the dosage ofHA≤50 mg/L,HA promotes the total nitrogen removal rate(NRR)to 1.45 kg/(m^(3)·day).When HA was between 50 and 100 mg/L,the NRR of Anammox was stable.At this time,the adsorption of HA causes the sludge to gradually turn fromred to brown,but the activities of heme and enzymes showed that its capacitywas not affected.When HA levels reached 250 mg/L,the NRR dropped to 0.11 kg/(m^(3)·day).Moderate HA levels promoted the release of extracellular polymeric substance(EPS),but excessive HA levels lead to a decrease in EPS concentrations.HA inhibited Anammox activity,which indirectly hindered the transmission of substrate and accumulated substrate toxicity.Although HA promoted the increase of heterotrophicmicrobial abundance in Anammox system,the microbial diversity decreased gradually.With the increase of HA concentration,the abundance of Candidatus_Brocadia,the main functional microorganism of Anammox system,decreased gradually,while the abundance of Candidatus_Kuenenia increased gradually.
