Evaluate the partial nitrification/anammox biofilm system treating the anaerobic biogas slurry of multisource organic solid waste

Abstract

Anaerobic digestion used for treating organic solid waste (OSW) usually produces much biogas slurry with high ammonia levels and low C/N ratio, suitable for partial nitrification/anammox (PN/A) process. However, the multisource OSW makes the biogas slurry complex, which may affect the stability of PN/A system. Therefore, this study explored the performance of a PN/A biofilm system treating biogas slurry with different water qualities. Different biogas slurry slightly affected nitrogen removal efficiency of the system (maintained at 90 %), whereas the contribution of anammox decreased gradually. The organic compounds in the biogas slurry were complex and difficult to degrade, but changed the microbial structure of the system. Complex biogas slurry promoted extracellular polymeric substances (EPS) secretion, helped maintain the stability of the biofilm and reduce the impact of the external environment. The relative abundance of Candidatus_Kuenenia, which was the dominant anammox genus, decreased from 9.02 % to 1.26 %. In addition, the relative abundance of Denitratisoma and Thauera decreased sharply, however, that of Truepera increased from 0.07 % to 6.52 %, making it the dominant denitrifying bacterial genus in the system. This study provides a reference for application of PN/A systems in the treatment of actual biogas slurry.