Impact of carbon source and COD/N on the concurrent operation of partial denitrification and anammox

Abstract

In this study, concurrent operation of anammox and partial denitrification within a nonacclimated mixed culture system was proposed. The impact of carbon sources (acetate, glycerol, methanol, and ethanol) and COD/NO3 − -N ratio on partial denitrification selection under both short-and long-term operations were investigated. Results from short-term testing showed that all carbon sources supported partial denitrification. However, acetate and glycerol were preferred due to their display of efficient partial denitrification selection, which may be related to their different electron transport pathways in comparison with methanol. Long-term operation confirmed results of batch tests by showing the contribution of partial denitrification to nitrate removal above 90% after acclimation in both acetate and glycerol reactors. In contrast, methanol showed challenges of maintaining efficient partial denitrification. COD/NO3 − -N ratio mainly controlled the rate of nitrate reduction and not directly partial denitrification selection; thus, it should be used to balance between denitrification rate and anammox rate. © 2018 Water Environment Federation • Practitioner points• The authors aimed to investigate the impact of carbon sources and COD/NO3 − -N ratio on partial denitrification selection. • All the carbon sources supported partial denitrification as long as the nitrite sink was available. • 90% partial denitrification could be achieved with both acetate and glycerol in long-term operations. • COD/NO3 − -N ratio did not directly control partial denitrification but can be used to balance between denitrification rate and anammox rate.

Primary sludge fermentate as carbon source for mainstream partial denitrification–anammox (PdNA)

“…93% PdN efficiency observed in the batch kinetic studies, 2. 80% PdN efficiency at the highest possible target, achieved in the mainstream pilot with acetate as COD source (Le et al, 2019a), 3. Lower ranges of PdN efficiency (60%, 50%, and 30%) which were based on results from pilot testing with fermentate.…”

Nitrate residual as a key parameter to efficiently control partial denitrification coupling with anammox

“…While the AnAOB process is easily controlled whenever nitrite is available, PdN selection has become a critical step determining success of the PdN‐AnAOB approach (Kumar & Lin, ). Nitrite accumulation as indicator of PdN has been reported in many studies when fast carbon sources such as acetate (Du et al, ; Ge et al, ; Gong et al, ; Le et al, ; Van Rijn, Tal, & Barak, ; Yang, Wang, & Zhou, ) or glycerol (Baideme et al, ; Bill et al, ; Park, Brotto, Loosdrecht, & Chandran, ; Sharp et al, ; Uprety, ) were used for denitrification. Furthermore, other research also showed that COD/N ratio, pH, DO level, and SRT could be important factors impacting PdN performance (Almeida, Júlio, Reis, & Carrondo, ; Beccari, Passino, Ramadori, & Tandoi, ; Glass & Silverstein, ; Obaja, MacÉ, & Mata‐Alvarez, ).…”

New Insight into Partial Denitrification (PD)-based Anammox Process and Potential Engineering Application: A Review

“…Previous literatures have evidenced that simple micromolecule organic materials could easily harvest NO 2 --N accumulating organisms compared with complex carbon source. For instance, ethanol [26], methanol [23], acetate [27], even the biodegradable organics in urban sewage were exploited as denitrifiers electronic donors. However, easily biodegradable organics were rarely detected in current practical wastewater, i.e., municipal wastewater, sludge digestion solution and manufacturing wastewater.…”

“…--N in raw wastewater, which was critical factor for terminating NO 3 --N reduction only to NO 2 --N. The ratio of COD/NO 3 --N largely determined the denitrification process and controlled the reduction rate of NO 3 --N [26]. Widely reported appropriate COD/NO 3 --N ratio for PD process ranged from 2.0~3.5, of which high NTR performance and anammox bacteria suitable influent substrate (NH 4 + -N/NO 2 --N=1.30) could be available [8,22,31].…”