Newly established process combining partial hydrogenotrophic denitrification and anammox for nitrogen removal

Abstract

The anaerobic ammonium oxidation (anammox) process holds great promise for treating nitrogen-contaminated water; stable nitrite-nitrogen (NO2--N) production is significant to anammox performance. In this study, partial hydrogenotrophic denitrification (PHD) was used to stably and efficiently produce NO2--N from nitrate-nitrogen (NO3--N). An investigation of the effects of initial pH on the PHD process revealed that a high NO2--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 (NH4+-N), NO3--N, and total dissolved inorganic nitrogen removal efficiencies of 93.4, 98.0, and 86.9%, respectively. The NO2--N to NH4+-N and NO3--N to NH4+-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.

Investigation of nitrite accumulation by hydrogenotrophic denitrification in a moving bed biofilm reactor for partial denitrification and anammox process

“…In ideal operating conditions, the MBBR had an NRE of 89.2+8.9%, with NO À 2 -N accumulation at an NAE of 64.4+14.5%, indicating that NO À 3 -N residue was minimized and NO À 2 -N accumulation was simultaneously sustained for the subsequent anammox reaction in the PDA process. Shinoda et al (2020) reported NRE and NAE values of 88.1% and 96.7%, respectively, in a HD reactor operated at a highly alkaline pH (10.5). This NAE is 1.5 times higher than the value obtained herein.…”

Hydrogen injection reduces ammonia nitrogen and changes microbial community composition in aquaculture water

“…Compared with other physical and chemical methods such as adsorption method, chemical precipitation method and active metal reduction method, it has the characteristics of lower cost such as no addition of potentially toxic chemical reagents, harmless to cultured animals, simple operation and easy maintenance (Broman et al, 2017;Zha et al, 2020). It has achieved remarkable results in many water treatment fields such as high ammonia wastewater treatment and drinking water treatment, and most of these applications tested by the hydrogen nutrition process have achieved high efficiency and high denitrification rate (Karanasios et al, 2010;Shinoda et al, 2020).…”