A novel completely autotrophic biological treatment process coupled of anammox and sulfur autotrophic (CAS) reactors to remove nitrogen and perchlorate simultaneously

A coupled system of anammox and sulfur autotrophic (CAS) reactors was established to remove ammonia (NH4+-N) and perchlorate (ClO4-) simultaneously in wastewater. The anammox performed NH4+-N removal and the sulfur autotrophs removed nitrate (NO3--N) produced by anammox and ClO4- in influent. When the concentrations of ClO4-, NO3--N and NH4+-N in the CAS were 30–90 mg/L, 100 mg/L and 120 mg/L, respectively, the removal rates of TN and ClO4- by CAS were 99 % and 98 %. The synergistic mechanism of CAS indicated that the secretion of extracellular polymeric substances (EPS) could cope with the impact of ClO4-, so as to ensure the removal performance of NH4+-N and ClO4- and electron transfer system activity (ETSA). High throughput sequencing revealed that the dominant genera were Candidatus Kuenenia, Candidatus Brocadia, Armatimonadetes gp5 and Gp10 in the anammox reactor, and the seven dominant genera were Methyloversatilis, Methylocystis, Ancalomicrobium, Longilinea, Thermogutta, Sulfurimonas and Ferritrophicum in the sulfur autotrophic reactor. The dominant bacteria supported the feasibility of the CAS. Consequently, the CAS provided an effective technical path for the simultaneous removal of NH4+-N and ClO4- in practical application.