Nitrate Reduction Research Articles

Hydrogeology and subsurface water flow beneath grass waterways: Implications for exploiting waterways for nitrate reductions

Hydrogeology and subsurface water flow beneath grass waterways: Implications for exploiting waterways for nitrate reductions

Cu1-Fe Dual Sites for Superior Neutral Ammonia Electrosynthesis from Nitrate.

The electrochemical nitrate reduction reaction (NO3RR) is able to convert nitrate (NO3-) into reusable ammonia (NH3), offering a green treatment and resource utilization strategy of nitrate wastewater and ammonia synthesis. The conversion of NO3- to NH3 undergoes water dissociation to generate active hydrogen atoms and nitrogen-containing intermediates hydrogenation tandemly. The two relay processes compete for the same active sites, especially under pH-neutral condition, resulting in the suboptimal efficiency and selectivity in the electrosynthesis of NH3 from NO3-. Herein, we constructed a Cu1-Fe dual-site catalyst by anchoring Cu single atoms on amorphous iron oxide shell of nanoscale zero-valent iron (nZVI) for the electrochemical NO3RR, achieving an impressive NO3- removal efficiency of 94.8% and NH3 selectivity of 99.2% under neutral pH and nitrate concentration of 50 mg L-1 NO3--N conditions, greatly surpassing the performance of nZVI counterpart. This superior performance can be attributed to the synergistic effect of enhanced NO3- adsorption on Fe sites and strengthened water activation on single-atom Cu sites, decreasing the energy barrier for the rate-determining step of *NO-to-*NOH. This work develops a novel strategy of fabricating dual-site catalysts to enhance the electrosynthesis of NH3 from NO3-, and presents an environmentally sustainable approach for neutral nitrate wastewater treatment.

Enhancing selective nitrate-to-ammonia electrocatalysis with high-performing Ni2P embedded nitrogen phosphide doped carbon (NPC) deposited on CP: Unprecedented performance and stability

One of the biggest challenges to the sustainable manufacture of liquid ammonia and the prevention of worldwide water contamination is the development of effective electrocatalysts for the electrochemical reduction of nitrate (NO3−) to NH3 with high stability. Herein, a highly active and serviceable electrocatalyst is synthesized by pyrolysis, composed of nanostructure nickel phosphide (Ni2P) embedded in nitrogen phosphide doped carbon (NPC) followed by deposition on carbon paper (CP) to improve the electrocatalytic nitrate reduction. Various characterization techniques investigate the crystallinity, morphology, and chemical components of the Ni2P-NPC/CP nanoparticles. The results support the formation of nanostructure Ni2P and strong synergistic interactions between Ni2P and NPC, which resulted in substantial active sites and high electrical conductivity. Excellent performance of Ni2P-NPC/CP nanoparticles is achieved for electrocatalytic NO3− reduction with an NH4+ yield rate of 2.468 mg h−1 mgcat.−1 and Faradaic efficiency (FE) of 84.6% at −1.2 V vs. RHE. Additionally, Ni2P-NPC/CP nanoparticles exhibit exceptional robustness and endurance. Studies using isotope labeling have been carried out, and the results show that nitrate reduction produces ammonia. Ni2P-based electrocatalysts can effectively treat nitrate wastewater to recover ammonia and facilitate its use in diverse industrial applications.

High Entropy Borides as Efficient Catalysts for Electrochemical Reduction of Nitrate to Ammonia

Electrochemical reduction of nitrate (NO3-RR) to ammonia has attracted great attention as a strategy for simultaneously achieving pollutant removal and economic product acquisition. To achieve high Faradaic efficiency of ammonia (FE) and ammonia selectivity, it is necessary to develop highly active catalysts with strong hydrogenation ability. In this work, we report high-entropy-borides (HEB) with tunable cation composition as high-performance catalysts for NO3-RR. Taking (TiVCrMo)B2 as the model material systems, we systematically investigate the effect of doping (Co, Fe and Ni) on the activity of NO3-RR. Electrochemical test results show that the HEB doped with Co element exhibited the optimal performance, with a FE reaching 97.9%. Combining several advanced spectroscopic techniques, we find that Co dopant can effectively facilitate the hydrogenation process of NO3-RR. This work demonstrates high-entropy ceramics as an excellent platform for rational design of highly active catalyst for energy and environmental applications.

Enhancing iron biogeochemical cycling for canga ecosystem restoration: insights from microbial stimuli

IntroductionThe microbial-induced restoration of ferruginous crusts (canga), which partially cover iron deposits and host unique ecosystems, is a promising alternative for reducing the environmental impacts of the iron mining industry.MethodsTo investigate the potential of microbial action to accelerate the reduction and oxidation of iron in substrates rich in hematite and goethite, four different microbial treatments (water only as a control − W; culture medium only − MO; medium + microbial consortium − MI; medium + microbial consortium + soluble iron − MIC) were periodically applied to induce iron dissolution and subsequent precipitation. Except for W, all the treatments resulted in the formation of biocemented blocks.ResultsMO and MI treatments resulted in significant goethite dissolution, followed by precipitation of iron oxyhydroxides and an iron sulfate phase, due to iron oxidation, in addition to the preservation of microfossils. In the MIC treatment, biofilms were identified, but with few mineralogical changes in the iron-rich particles, indicating less iron cycling compared to the MO or MI treatment. Regarding microbial diversity, iron-reducing families, such as Enterobacteriaceae, were found in all microbially treated substrates.DiscussionHowever, the presence of Bacillaceae indicates the importance of fermentative bacteria in accelerating the dissolution of iron minerals. The acceleration of iron cycling was also promoted by microorganisms that couple nitrate reduction with Fe(II) oxidation. These findings demonstrate a sustainable and streamlined opportunity for restoration in mining areas.

Modulation of Reactive Hydrogen Adsorbed on Dual-Active Site NiMoO4 Nanocubes for Reduction of Nitrate to Ammonia

Modulation of Reactive Hydrogen Adsorbed on Dual-Active Site NiMoO₄ Nanocubes for Reduction of Nitrate to Ammonia

Graphdiyne Enabled Nitrogen Vacancy Formation in Copper Nitride for Efficient Ammonia Synthesis.

The electrocatalytic reduction of nitrate is promising for sustainable ammonia synthesis but suffers from slow reduction kinetics and multiple competing reactions. Here, we report a catalyst featuring copper nitride (Cu3N) anchored on a novel graphdiyne support (termed Cu3N/GDY), which is used for electrocatalytic reduction of nitrate to produce ammonia. The GDY absorbed hydrogen and enabled nitrogen (N) vacancy formation in Cu3N for the fast nitrate reduction reaction (NO3RR). Further, the distinct absorption sites formed by GDY and N vacancy enabled the excellent selectivity and stability of NO3RR. Notably, the Cu3N/GDY catalyst achieved a high ammonia yield (YNH3) up to 35280 μg h-1 mgcat.-1 and a high Faradaic efficiency (FE) of 98.1% using 0.1 M NO3- at -0.9 V versus a reversible hydrogen electrode (RHE). Using electron paramagnetic resonance (EPR) technology and in situ X-ray absorption fine structure (XAFS) spectroscopy measurement, we visualized the N vacancy formation in Cu3N and electrocatalytic NO3RR enabled by GDY. These findings show the promise of GDY in sustainable ammonia synthesis and highlight the efficacy of Cu3N/GDY as a catalyst.

Boosting Electrochemical Ammonia Synthesis via NOx Reduction over Sulfur‐Doped Copper Oxide Nanoneedle Arrays

Boosting Electrochemical Ammonia Synthesis via NO<i>_x</i> Reduction over Sulfur‐Doped Copper Oxide Nanoneedle Arrays

Review on electrocatalytic nitrate reduction to ammonia: advances, challenges and future prospects

Review on electrocatalytic nitrate reduction to ammonia: advances, challenges and future prospects

Electrocatalytic Nitrate Reduction on Metallic CoNi-Terminated Catalyst with Industrial-Level Current Density in Neutral Medium.

Green ammonia synthesis through electrocatalytic nitrate reduction reaction (eNO3RR) can serve as an effective alternative to the traditional energy-intensive Haber-Bosch process. However, achieving high Faradaic efficiency (FE) at industrially relevant current density in neutral medium poses significant challenges in eNO3RR. Herein, with the guidance of theoretical calculation, a metallic CoNi-terminated catalyst is successfully designed and constructed on copper foam, which achieves an ammonia FE of up to 100% under industrial-level current density and very low overpotential (-0.15V versus reversible hydrogen electrode) in a neutral medium. Multiple characterization results have confirmed that the maintained metal atom-terminated surface through interaction with copper atoms plays a crucial role in reducing overpotential and achieving high current density. By constructing a homemade gas stripping and absorption device, the complete conversion process for high-purity ammonium nitrate products is demonstrated, displaying the potential for practical application. This work suggests a sustainable and promising process toward directly converting nitrate-containing pollutant solutions into practical nitrogen fertilizers.

Ru-Doped NiFe-MIL-53 with Facilitated Reconstruction and Active Hydrogen Supplement for Enhanced Nitrate Reduction.

The Electrochemical reduction of nitrate to ammonia (NH3) is a process of great significance to energy utilization and environmental protection. However, it suffers from sluggish multielectron/proton-involved steps involving coupling reactions between different reaction intermediates and active hydrogen species (Hads) produced by water decomposition. In this study, a Ru-doped NiFe-MIL-53 (NiFeRu-MIL-53) supported on Ni foam (NF) has been designed for the nitrate reduction reaction (NO3RR). The NiFeRu-MIL-53 exhibits excellent NO3RR activity with a maximum Faradaic efficiency (FE) of 100% at -0.4 V vs. RHE for NH3 and a maximum NH3 yield of 62.39 mg h-1 cm-2 at -0.7 V vs. RHE in alkaline media. This excellent performance for the NO3RR is attributed to a strong synergistic effect between Ru and reconstructed NiFe(OH)2. Additionally, the doped Ru facilitates water dissociation, leading to an appropriate supply of Hads required for N species hydrogenation during NO3RR, thereby further enhancing its performance. Furthermore, in situ Raman analysis reveals that incorporating Ru facilitates the reconstruction of MOFs and promotes the formation of hydroxide active species during the NO3RR process. This work provides a valuable strategy for designing electrocatalysts to improve the efficiency of the reduction of electrochemical nitrate to ammonia.

Tailoring Ni 3d orbitals in Ni-Fe/Ni foam heterostructures for enhanced H* adsorption and boosted electrocatalytic nitrate reduction performance

The electrochemical nitrate (NO3−) reduction (ENR) in wastewater, a promising remediation strategy, is often impeded by the essential use of costly noble metals. This study introduces an innovative non-noble Ni-Fe/Ni foam cathode fabricated via one-step electrodeposition technique. Efficient nitrate removal (99.4 %) was achieved with the selectivity of 83.6 % to NH3. The exceptional performance can be ascribed to the augmented active sites and the synergistic interaction between Ni and Fe. The leftward shift of the 3d orbitals density of Ni and the elevation of density at the Fermi level on Ni foam heterostructures, consequent to Fe doping, enhance the adsorption of H*. The addition of reactive chlorine species, generated through anodizing in Cl− mediated system, further improves N2 selectivity by oxidizing intermediate NH4+ product. The coupled anodic oxidation method employed herein achieves nearly 100 % removal efficiency of total nitrogen (TN) for initial concentration of 100 mg/L within 180 min, under the conditions of 1.5 g/L Cl− concentration and a current density of 25 mA cm−2. The findings underscore the potential of the Ni-Fe/Ni foam cathode within a Cl− mediated electrocatalytic framework for nitrate wastewater treatment, providing novel insights into the design of cathode catalysts and anodic coupling strategies for efficient TN removal.

Subnanometer‐sized CuOx Clusters on TiO2 as Active Photocatalysts for Ammonia Production from Photocatalytic Nitration Reduction Reaction

The Haber‐Bosch process is commonly used to produce ammonia while consuming energy and yielding huge emissions of carbon dioxide. Finding an alternative way to produce ammonia sustainably is a promising research direction with less CO2 emission. Photochemical nitrate reduction reaction (NtRR) to ammonia (NH3) could solve the nitrate pollutant problem in water and approach to produce ammonia with a more environmentally friendly process and lower energy consumption. In this work, the subnanometer‐sized copper oxide clusters decorated on titanium oxide nanoparticles (CuOx‐TiO2) were synthesized through the hydrothermal method and calcination treatment. CuOx‐TiO2 demonstrated impressively conversion rate of NO3‐ to NH3 with a yield of 153.09 μg‐gcat‐1‐h‐1 in KNO3 solution. The characteristic structure analysis revealed CuOx clusters with ~less than 1 nm decorated on TiO2 nanoparticles. From in‐situ X‐ray absorption fine structure (XAFS) spectroscopic technique, the transformation of the oxidation state of Cu clusters and the changes of local structure in the CuOx‐TiO2 were observed. The photocatalytic reaction mechanism of nitrate reduction on the CuOx‐TiO2 was successfully revealed. These discoveries have broad implications for the functional advancement of catalysts based on subnanometer‐sized clusters. Our findings may pave the way for exploring advanced ammonia synthesis routes with reduced energy consumption and carbon emissions.

Synergies of chemodenitrification and denitrification in a saline inland lake

The interconnection between biotic and abiotic pathways involving the nitrogen and iron biogeochemical cycles has recently gained interest. While lacustrine ecosystems are considered prone to the biotic nitrate reduction (denitrification), their potential for promoting the abiotic nitrite reduction (chemodenitrification) remains unclear. In the present study, batch incubations were performed to assess the potential for chemodenitrification and denitrification in the saline inland lake Gallocanta. Sulfidic conditions are found in top sediments of the system while below (5–9 cm), it presents low organic carbon and high sulfate and ferrous iron availability. Anoxic incubations of sediment (5–9 cm) and water from the lake with nitrite revealed potential for chemodenitrification, especially when external ferrous iron was added. The obtained isotopic fractionation values for nitrite (ɛ15NNO2) were −6.8 and −12.3 ‰ and therefore, fell in the range of those previously reported for the nitrite reduction. The more pronounced ɛ15NNO2 (−12.3 ‰) measured in the experiment containing additional ferrous iron was attributed to a higher contribution of the chemodenitrification over biotic denitrification. Incubations containing nitrate also confirmed the potential for denitrification under autotrophic conditions (low organic carbon, high ferrous iron). Higher reaction rate constants were found in the experiment containing 100 μM compared to 400 μM nitrate. The obtained ɛ15NNO3 values (−8.5 and −15.1 ‰) during nitrate consumption fell in the range of those expected for the denitrification. A more pronounced ɛ15NNO3 (−15.1 ‰) was determined in the experiment presenting a lower reaction rate constant (400 μM nitrate). Therefore, in Gallocanta lake, nitrite generated during nitrate reduction can be further reduced by both the abiotic and biotic pathways. These findings establish the significance of chemodenitrification in lacustrine systems and support further exploration in aquatic environments with different levels of C, N, S, and Fe. This might be especially useful in predicting nitrous oxide emissions in natural ecosystems.

Development of a method for quantitative determination of nitric oxide (NO) in rat tissues based on high-performance liquid chromatography and mass spectrometry

A quantitative assessment of nitric oxide (NO) production in body tissues is an urgent problem in pharmacology and biochemistry. The study of physiological processes occurring with the participation of NO, as well as the metabolism and pharmacodynamics of pharmacological agents from the group of NO donors, requires the introduction of accurate and reproducible methods for the quantitative determination of this metabolite in biological media.The aim of the study was to develop the HPLC-MS/MS methods for the quantitative determination of NO in various tissues of rats.Materials and methods. The indirect NO quantification was based on estimation of the level of more stable metabolites: nitrites and nitrates extracted from rat tissues by homogenization with water. The reduction of nitrates to nitrites was carried out using nitrate reductase. The derivatization of nitrites was based on a reaction with Griess reagent. The resulting azo dye was determined by HPLC-MS/MS using an Agilent InfinityLab Poroshell 120 EC-C18 4.6×100 mm, 2.7 μm analytical column. The total chromatographic analysis time was 12 minutes, and the analyte retention time was 6.1 minutes. The analytical range of the method was 0.1–100.0 nmol (in terms of nitrite) per 1 ml of plasma or tissue homogenate.Results. The developed a bioanalytical method was validated according to the following parameters: a selectivity, a matrix effect, a recovery degree, a sample transfer, an analytical range linearity, a lower limit of quantification (LLOQ), an intra- and inter-assay accuracy and precision, and a stability at all the stages of the analysis. To test the method, the NO content in the plasma, brain, heart, aorta and lungs of rats was determined.Conclusion. The developed bioanalytical HPLC-MS/MS methods fully meets the validation requirements. The metrological characteristics of the technique make it possible to highly accurately estimate the NO production in various tissues of rats, which is undoubtedly relevant and in demand in the study of pathological processes as well as the mechanism of action of pharmacological agents from the group of NO donors.

Theoretically exploring bioinspired enzyme-like [formula omitted] with organic ion axial ligand for electrocatalytic nitrate reduction to ammonia

Electrocatalytically driven reduction of nitrate (NO3−) from NO3−-laden wastewater to ammonia (NH3) has emerged as a promising complementary strategy to the energy-intensive Haber-Bosch process. Herein, based on density functional theory (DFT) calculations, 14 organic ionic groups are found to significantly improve the electrocatalytic reduction of NO3− to NH3 (eNO3RR-to-NH3) activity of typical M−N4−C (M = Fe, Co, and Ni) catalysts by axially ligating metal center, among which Ethyl thiolate axially ligated Co−N4−C exhibits the highest eNO3RR-to-NH3 activity with the limiting potential (UL) of -0.11 V. 4-Mercaptobenzoic acid and Thiophenolate axially ligated Fe−N4−C can inhibit the NN coupling reaction while having high eNO3RR-to-NH3 activity (UL = -0.16, -0.31 V, respectively) and thus have better NH3 selectivity. Furthermore, ΔGH*NO and ICOHP (integrated crystal orbital hamilton populations) between the 3d orbital of M and 2p orbital of N (*NO) atoms show remarkable volcano relationship for L−Fe−N4−C systems and linear relationship with R-Square of 0.83 occurs for L−Co−N4−C systems. There is an excellent linear relationship (R-Square is 0.88) between ICOHP and UL for the L−Co−N4−C systems. Hence, the ICOHP can work as an excellent thermodynamic activity descriptor for eNO3RR-to-NH3 over L−Co−N4−C catalysts. The three catalysts are concluded to be promising electrocatalysts for eNO3RR-to-NH3.

Bacterial Community Characteristics and Roles in Nitrogen Transformation in Industrial Farming Systems of Litopenaeus vannamei

Industrial farming is one of the main farming systems used for L. vannamei, and it is also the main direction of development in the future. To investigate the role of the bacterial community in nitrogen transformation in industrial L. vannamei farming systems, we studied the concentration of nitrogen compounds, the bacterial community using 16S rRNA sequencing, and nitrogen cycling genes’ abundance using absolute quantitative PCR in aquaculture water (using seawater (WD) and groundwater mixed with seawater (CY)) and analyzed the correlations between them using a person analysis. The results showed that the bacterial α-diversity index (ACE, Shannon, and Sobs) significantly changed during culture in WD but not in CY. Bacterial community species composition analysis and linear discriminant analysis effect size (LEfSe analysis) revealed that Cyanobiaceae and Microbacteriaceae were the dominant bacteria and biomarkers in WD. Vibrionaceae, Ateromonadaceae, Microbacteriaceae, Saprospiraceae, and Cryomorphaceae were the dominant bacteria and biomarkers in CY. A functional annotation of procaryotic taxa (FAPROTAX) analysis revealed that the bacterial community in WD exhibited a greater phototrophic activity at early culture stages, while at the same stage, CY exhibited strong nitrate reduction. A correlation analysis of nitrogen cycling genes and environmental factors revealed that napA, narG, ureC, amoA, and nirK were significantly correlated with the concentrations of total ammonia nitrogen (TAN), nitrite (NO2−-N), nitrate (NO3−-N), and total nitrogen (TN) in WD. In CY, amoA was positively correlated and napA and nirK were negatively correlated with TAN and TN concentrations. A correlation analysis between bacterial abundance and environmental factors revealed that Flavobacteriaceae, Saprospiraceae, Cryomorphaceae, Cyanobiaceae, Halieaceae, and Cyclobacteriaceae were significantly correlated with the concentrations of TAN and NO2−-N. The above results indicated that the bacterial community in industrial shrimp farming systems changed under different conditions, with consequent changes in the abundance of genes being involved in the nitrogen cycle and in this biogeochemical process in the water. Our study facilitates further understanding of microbes and their functions in nitrogen cycling in industrial shrimp farming systems.

Long-term source apportionment of PM2.5 across the contiguous United States (2000-2019) using a multilinear engine model

Identifying PM2.5 sources is crucial for effective air quality management and public health. This research used the Multilinear Engine (ME-2) model to analyze PM2.5 from 515 EPA Chemical Speciation Network (CSN) and Interagency Monitoring of Protected Visual Environments (IMPROVE) sites across the U.S. from 2000 to 2019. The U.S. was divided into nine regions for detailed analysis. A total of seven source types (tracers) were resolved across the country: (1) Soil/Dust (Si, Al, Ca and Fe); (2) Vehicle emissions (EC, OC, Cu and Zn); (3) Biomass/wood burning (K); (4) Heavy oil/coal combustion (Ni, V, Cl and As); (5) Secondary sulfate (SO42-); (6) Secondary nitrate (NO3-) and (7) Sea salt (Mg, Na, Cl and SO42-). Furthermore, we extracted and calculated secondary organic aerosols (SOA) based on the secondary sulfate and nitrate factors. Notably, significant reductions in secondary sulfate, nitrate, and heavy oil/coal combustion emissions reflect recent cuts in fossil-fueled power sector emissions. A decline in SOA suggests effective mitigation of their formation conditions or precursors. Despite these improvements, vehicle emissions and biomass burning show no significant decrease, highlighting the need for focused control on these persistent pollution sources for future air quality management.

Highly selective and stable electrochemical reduction of nitrate to ammonia using VO2-x/CuF catalyst with oxygen vacancies

Electrocatalytic reduction poses significant challenges due to slow kinetics, limited selectivity, and instability, hindering its potential for sustainable nitrate (NO3−) removal and producing valuable N-containing compounds. This study develops a one-step hydrothermal approach for decorating copper foam (CuF) with VO2 nanobelts. Subsequently, N2 annealing is performed to generate oxygen vacancies (OVs) and yield a VO2-x/CuF sample for its application as an electrocatalyst in reducing NO3− to ammonia (NH3). Several characterization techniques are applied to study the structural and morphological features of the VO2-x/CuF sample, which shows a high crystalline and defective bundle-like structure of nanobelts attributed to the release of oxygen atoms that are beneficial for the electrochemical NO3− reduction processes. The VO2-x/CuF sample demonstrates impressive results, with a NO3− conversion of 78.7 %, an NH4+ yield rate of 1.833 mmol h−1 cm−2, an NH4+ FE of 77.9 %, and a remarkable NH4+ selectivity of 99.7 % at −1.3 V vs RHE. It is worth mentioning that the isotopic labeling findings reveal that the NH4+ originated from NO3− during the electrocatalytic NO3− reduction using a VO2-x/CuF sample. This confinement method effectively creates accessible metallic catalysts with OVs, enabling high-activity, selective and stable NO3− reduction to NH4+ electrocatalysts.

Salt stimulates sulfide−driven autotrophic denitrification: Microbial network and metagenomics analyses

Sulfur autotrophic denitrification (SADN) is a promising biological wastewater treatment technology for nitrogen removal, and its performance highly relies on the collective activities of the microbial community. However, the effect of salt (a prevailing characteristic of some nitrogen−containing industrial wastewaters) on the microbial community of SADN is still unclear. In this study, the response of the sulfide−SADN process to different salinities (i.e., 1.5 % salinity, 0.5 % salinity, and without salinity) as well as the involved microbial mechanisms were investigated by molecular ecological network and metagenomics analyses. Results showed that the satisfactory nitrogen removal efficiency (>97 %) was achieved in the sulfide−SADN process (S/N molar ratio of 0.88) with 1.5 % salinity. In salinity scenarios, the genus Thiobacillus significantly proliferated and was detected as the dominant sulfur−oxidizing bacteria in the sulfide−SADN system, occupying a relative abundance of 29.4 %. Network analysis further elucidated that 1.5 % salinity had enabled the microbial community to form a more densely clustered network, which intensified the interactions between microorganisms and effectively improved the nitrogen removal performance of the sulfide−SADN. Metagenomics sequencing revealed that the abundance of functional genes encoding for key enzymes involved in SADN, dissimilatory nitrate reduction to ammonium, and nitrification was up−regulated in the 1.5 % salinity scenario compared to that without salinity, stimulating the occurrence of multiple nitrogen transformation pathways. These multi−paths contributed to a robust SADN process (i.e., nitrogen removal efficiency >97 %, effluent nitrogen <2.5 mg N/L). This study deepens our understanding of the effect of salt on the SADN system at the community and functional level, and favors to advance the application of this sustainable bioprocess in saline wastewater treatment.