Application of natural biodegradable fiber as biofilm medium and carbon source in DEnitrifying AMmonium OXidation (DEAMOX) process for nitrogen removal from wastewater

Nitrite (NO2-) accumulation and retaining of anammox bacteria are two decisive factors for stable operation of partial denitrification coupled with the anammox process. Denitrifying ammonium oxidation (DEAMOX) process has been regarded as a promising method for nitrogen removal from wastewater containing both ammonium (NH4+) and nitrate (NO3-) pollutants simultaneously. However, performance and efficiency of DEAMOX process in biofilm reactors are still not fully understood. This study successfully implements biode-gradable Luffa Cylindrica fiber as both carbon source and biofilm carrier in the DEAMOX system. 87% nitrate-to-nitrite transformation was achieved through the partial denitrification process. An average total nitrogen (TN) removal efficiency of similar to 98% was obtained with influent NH4+-N and NO3--N concentration of 100 mg L-1 in an up-flow packed bed biofilm reactor. The Field Emission-Scanning Electron Microscopy (FE-SEM) analy-sis indicated that for the proposed conditions, the DEAMOX packed bed reactor favor biofilm granulation developed on L. cylindrica. The results imply that solid phase partial denitrification and granulation of anam-mox bacteria were achieved using L. cylindrica as a carbon source and biofilm carrier, respectively. Complete NO3- removal observed in this study supports the hypothesis that solid carbon source can support denitrifi-cation of NO3- produced through the anammox process. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved