Achieving complete nitrogen removal by coupling nitritation‐anammox and methane‐dependent denitrification: A model‐based study

Abstract

The discovery of denitrifying anaerobic methane oxidation (DAMO) processes enables the complete nitrogen removal from wastewater by utilizing the methane produced on site from anaerobic digesters. This model-based study investigated the mechanisms and operational window for efficient nitrogen removal by coupling nitritation-anaerobic ammonium oxidation (Anammox) and methane-dependent denitrification in membrane biofilm reactors (MBfRs). A mathematical model was applied to describe the microbial interactions among Anammox bacteria, DAMO archaea, and DAMO bacteria. The model sufficiently described the batch experimental data from an MBfR containing an Anammox-DAMO biofilm with different feeding nitrogen compositions, which confirmed the validity of the model. The effects of process parameters on the system performance and microbial community structure could therefore be reliably evaluated. The impacts of nitritation produced NO2(-)/NH4(+) ratio, methane supply, biofilm thickness and total nitrogen (TN) surface loading were comprehensively investigated with the model. Results showed that the optimum NO2(-)/NH4(+) ratio produced from nitritation for the Anammox-DAMO biofilm system was around 1.0 in order to achieve the maximum TN removal (over 99.0%), independent on TN surface loading. The corresponding optimal methane supply increased while the associated methane utilization efficiency decreased with the increase of TN surface loading. The cooperation between DAMO organisms and Anammox bacteria played the key role in the TN removal. Based on these results, the proof-of-concept feasibility of a single-stage MBfR coupling nitritation-Anammox-DAMO for complete nitrogen removal was also tested through integrating the model with ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) processes whilst controlling the dissolved oxygen (DO) concentration in the simulated system. The maximum TN removal was found to be achieved at the bulk DO concentration of around 0.17 g m(-3) under the simulation conditions, with the AOB, Anammox bacteria and DAMO organisms coexisting in the biofilm.

Simultaneous nitrogen and phosphorus removal by combined anammox and denitrifying phosphorus removal process

“…Chen et al . attempted to resolve this problem by coupling nitritation–anammox and methane‐dependent denitrification, in which denitrifying anaerobic methane oxidation (DAMO) archaea converted nitrate to nitrite . Although Chen et al .…”

“…Chen et al attempted to resolve this problem by coupling nitritation-anammox and methane-dependent denitrification, in which denitrifying anaerobic methane oxidation (DAMO) archaea converted nitrate to nitrite. 5 Although Chen et al constructed a novel approach to the removal ammonium and methane simultaneously, this process could not bring about phosphorus removal at the same time. Thus, it is necessary to find another effective process to not only reduce nitrate in the effluent of the SNAP process, but also to achieve phosphorus removal simultaneously.…”

Simultaneous removal of ammonia nitrogen and manganese from wastewater using nitrite by electrochemical method

“…The results showed that the potential of 1.2583 V vs. SCE (saturated calomel electrode) could be attributed to oxygen evolution potential, [17][18][19] and the catalytic activity of Ti/RuO 2 -IrO 2 -SnO 2 maintained stability even after cyclic voltammograms tests (50 times). Figure 2 Moreover, the potential of 0.7575 and 1.7906 V vs. SCE can be attributed to the coupled oxidation of ammonia nitrogen and nitrite and oxygen evolution potential, [24][25][26] respectively. Meanwhile, Ti/ RuO 2 -IrO 2 -SnO 2 electrode can generate hydroxyl radicals on their surfaces under a certain potential; the adsorption of hydroxyl ions occurred at the electrodes before the oxygen evolution [27,28]; and ammonium nitrogen could be converted into nitrogen via hydroxyl Table 1.…”

Kinetics of anaerobic methane oxidation coupled to denitrification in the membrane biofilm reactor

“…Mathematical modeling studies have been conducted to mechanistically understand and ultimately optimize the performance of a CH 4 ‐based MBfR (Chen, Guo, Xie, Yuan, & Ni, ), but they were heavily focused on high‐strength wastewater containing nitrate and ammonium mixtures. This required that the model consider multiple types of active biomass, including AOM‐D archaea, AOM‐D bacteria, and anammox bacteria (Cai et al, , ; Haroon et al, ; Shi et al, ).…”