Nitrogen and phosphorus removal by coupling Anaerobic ammonia oxidation reaction with algal-bacterial symbiotic system

The pig farm wastewater after anaerobic digestion has attracted much attention due to its difficulty to be biochemically treated. This paper evaluated the potential of the combined anaerobic-aerobic process to treat digested wastewater from synthetic pig farms in terms of nitrogen, phosphorus, and organic compound removal. The experimental results showed that despite the low COD/TN(C/N) ratio of digested wastewater from pig farms, the removal efficiency of ammonium, total phosphorus (TP), and organic compound could reach 100%, 85%, and 87% respectively after reaching a steady-state by the combined anaerobic-aerobic process with an average hydraulic retention time of 3 days. The Anammox and Algae-Bacteria Symbiosis (An-ABS) system was significantly more effective than the Algae-Bacteria Symbiosis (ABS) system for nitrogen and phosphorus removal. When anaerobic ammonia-oxidizing granular sludge was introduced, the sedimentation performance of the algae-bacterial synergistic symbiotic system was significantly improved. The addition of anaerobic ammonia-oxidized granular sludge not only reduced the sludge diversity but also changed the sludge community structure. In addition, the suspended growth of Chlorella protected ammonia-oxidizing bacteria ( AOB ) and nitrite-oxidizing bacteria ( NOB ) from Optical damage. This study would provide some new insights into the combined anaerobic-aerobic process system for treating digested wastewater from synthetic pig farms, which would contribute to the development of low-energy wastewater treatment processes. All data generated and/or analyzed during this study are included in this published article and its supplementary files. ● An-ABS system was effective in treating pig farm wastewater after stabilization ● Improved sedimentation performance of algae-bacterial symbiotic systems ● Increased microbial abundance in the whole system ● The system has significance in reducing environmental pollution and saving energy