Newly established process combining partial hydrogenotrophic denitrification and anammox for nitrogen removal
Kenta Shinoda, Rawintra Eamrat, Yuya Tsutsumi, Suphatchai Rujakom, Tippawan Singhopon, Tatsuru Kamei, Futaba Kazama
Abstract
Abstract The anaerobic ammonium oxidation (anammox) process holds great promise for treating nitrogen-contaminated water; stable nitrite-nitrogen (-N) production is significant to anammox performance. In this study, partial hydrogenotrophic denitrification (PHD) was used to stably and efficiently produce -N from nitrate-nitrogen (-N). An investigation of the effects of initial pH on the PHD process revealed that a high -N production efficiency (77.9%) could be ensured by setting an initial pH of 10.5. A combined PHD-anammox process was run for more than three months with maximal ammonium-nitrogen (-N), -N, and total dissolved inorganic nitrogen removal efficiencies of 93.4, 98.0, and 86.9%, respectively. The -N to -N and -N to -N ratios indicated that various bioprocesses were involved in nitrogen removal during the anammox stage, and a 16S rRNA gene amplicon sequencing was performed to further clarify the composition of microbial communities and mechanisms involved in the nitrogen removal process.