Inhibitory Effect of Salinity and Humic Acid on the Performance of Anaerobic Ammonium Oxidation Process and Recovery of Anammox Activity

The anaerobic ammonium oxidation (Anammox) process can effectively treat the landfill leachate. However, the influences of complex components in landfill leachate on anammox bacteria were insufficiently understood. In this study, the single and combined influences of salinity and humic acid on the anammox process were investigated. The results showed that the initial nitrogen removal performance and the specific anammox activity in the salinity/humic acid group were lower than that of the single salinity or humic acid group. The simulation results of modified Boltzmann model showed that the median recovery time of the salinity/humic acid group was 18.82 days, which was 7.84 days longer than that of the salinity group alone. The reduction of electron transport system (ETS) activity might be the main reason for the deterioration of anammox activity. The ETS activity of the salinity/humic acid group was lower than that of the humic acid group or the salinity group, and was only 31.09% of the control group. The coexistence of salinity and humic acid resulted in the decrease of S = O and C-O functional groups, which related to the expression of electron transport enzymes and then disturbed seriously the ETS activity of anammox sludge.

Automated summary

The study found that the combination of salinity and humic acid had a negative impact on the Anammox process, possibly due to the reduction of ETS activity. Additionally, the coexistence of salinity and humic acid resulted in a decrease in functional groups, which in turn affected the ETS activity of the Anammox sludge.