Ultra-high efficiency simultaneous nitritation, denitritation and phosphorus removal from digestate centrate using calcium-enhanced aerobic granular sludge.

Functional microbial competition and evolution driven by increased chemical oxygen demand/nitrogen ratio and reduced temperatures in mainstream partial nitritation-anammox.

Synergistic transformation of alkylbisphenols (BPA, BPE, and BPF) mediated by ammonia-oxidizing bacteria and heterotrophic bacteria in nitrifying activated sludge.

Exploring the high-concentration powdered carrier bio-fluidized bed process nitrogen removal performance: Effect of dissolved oxygen.

Irreversible nitrite-oxidising bacteria inhibition by operational shutdowns for high‑ammonia wastewater treatment: from mechanism insights to pilot‑scale granular sludge reactor verification.

Linking carbon, nitrogen and sulfur cycles: Electron transfer model for nitrate and sulfate dependent anaerobic oxidation of methane.

Optimal glycine betaine threshold for enhancing partial denitrification-anammox performance under carbon starvation: Mechanisms and microbial responses.

Mechanisms of quinone-functionalized FeOOH for enhanced nitrogen removal in micro-aerobic activated sludge process treating low carbon-to-nitrogen ratio wastewater.

Biofiltration, seasonality, and distribution system factors influence nitrifier communities in a full-scale chloraminated drinking water system.

Membrane aerated biofilm reactor for largely enhanced nitrogen removal in low carbon/nitrogen ratio municipal wastewater: integrating nitrification, partial denitrification, and anammox.

Static magnetic fields enhance partial nitrification and phosphorus removal performance in anaerobic/aerobic/anoxic-aerobic granular sludge systems: Two-way role of microbial activity and extracellular polymeric substances.

Mechanistic insights into nitrite-type denitrifying phosphorus removal driven by iron-sulfur cycle-mediated electron transfer in pyrite-based constructed wetlands.

Mainstream anammox achieved in a two-stage acidophilic partial-nitrification/anammox system: Ultra-high enrichment of anammox bacteria and identification of a potential novel acidophilic ammonia-oxidizing bacterium.

Enrichment and nitrogen preference of heterotrophic nitrifying bacteria in the maize rhizosphere

Despite longstanding concerns over pesticide contamination in aquatic environments, their impacts on nitrogen-cycling functions in agricultural soils remain inadequately explored. This study employed target, suspect, and nontarget screening to identify residual pesticides and transformation products (TPs) in rapeseed-rice rotation soils, revealing associations with ammonia-oxidizing microorganisms (AOMs). Suspect and nontarget screening uncovered an additional eight pesticides and 14 TPs, including three novel TPs and three newly identified in environmental matrices. The mean total concentration of TPs (230 μg/kg dw) was comparable to that of the parent pesticides (221 μg/kg dw) with enrichment in the rhizosphere. Ammonia-oxidizing archaea and comammox Nitrospira were more susceptible to pesticides and TPs than ammonia-oxidizing bacteria. Notably, certain TPs imposed greater stress on AOMs than their parent compounds, especially in the rhizosphere. These findings suggest that pesticide-induced shifts in AOM abundance may alter soil nitrogen cycling, highlighting the need to investigate the long-term effects on nitrogen-cycling microorganisms in agricultural soils.

Global heatwave intensification under climate change will impact the nitrogen cycle, yet its effect on active nitrifier groups or their interactions with viruses remains unclear. Using 13CO2-DNA-based stable-isotope probing coupled with metagenomics, we show that elevated temperatures under heatwave conditions fundamentally restructure active nitrifying communities and their associated viruses in Yangtze River estuary upper tidal flats and adjacent agricultural soils. In tidal flats, sustained high temperature constrained nitrification by reducing the abundance of active ammonia-oxidizing archaea and bacteria (AOA, AOB) and canonical nitrite-oxidizing bacteria (NOB). This was accompanied by a shift in the active community from marine to more thermotolerant but less salt-tolerant terrestrial ecotypes. Conversely, heatwave conditions in agricultural soils suppressed AOB but enhanced nitrification activity in thermotolerant terrestrial AOA ecotypes. Across both ecosystems, inferred virus-nitrifier interactions were temperature dependent. 13C-labeled nitrifier-infecting viruses exhibited coordinated shifts in virus-to-host abundance ratios and predicted lifestyles with their hosts, with sustained high temperatures reducing virus-to-host abundance ratios and favoring temperate infections, relative to higher abundance ratios and a greater proportion of predicted lytic cycles at lower temperatures. We identified AOA-infecting viruses that carry plastocyanin (pcy), encoding a key copper-dependent electron carrier in the AOA respiratory chain, with conserved active sites and a predicted protein fold that supports its capacity for electron transfer, potentially augmenting host energy metabolism. Together, our findings demonstrate that prolonged heatwaves drive coupled shifts in nitrifier community composition and virus-host interaction strategies in a land-use-dependent manner, with implications for nitrogen transformations and ecosystem feedbacks under climate extremes.

Integration of real-time NH4+-N control and spatial microbial engineering achieves high removals of nitrogen and carbon in a sequence anoxic-oxic-anoxic (SAOA) system.

Nitrogen pollution poses significant risks to both environmental systems and human health. Iron-based autotrophic denitrification offers a green and cost-effective strategy for nitrogen removal, but is often accompanied by the accumulation of undesirable byproducts. A nitrogen removal system combining anammox with iron-based autotrophic denitrification was constructed in this study to investigate the enhancement effect of anaerobic ammonium-oxidizing bacteria (AnAOB). The results showed that during the stable operation phase, nitrate removal efficiencies reached 91.45% and 84.29% for groups A (0.5 g/L AnAOB) and B (0.1 g/L AnAOB), respectively, significantly higher than the 62.87% observed in the control group. Furthermore, the experimental groups exhibited markedly reduced accumulation of ammonium byproducts. Microbial community analysis revealed that AnAOB addition increased microbial richness and diversity, and promoted community shifts that favored nitrogen removal. Notably, even low dosages of AnAOB yielded strong performance enhancements, underscoring the economic viability of this integrated approach. Structural characterization using SEM, XRD, and XPS indicated that system performance deterioration in the later stages was primarily due to cell encrustation and iron passivation. Electrochemical analyses further demonstrated that iron passivation impaired electron transfer on the filler surface, thereby reducing denitrification efficiency, whereas extracellular polymeric substances (EPS) did not exhibit such inhibitory effects. These findings provide both mechanistic insight and practical guidance for the design and optimization of anammox-enhanced iron-based denitrification systems.

Since the discovery of anaerobic ammonium oxidation bacteria, commonly known as AnAOB in the early 1990s, more than a quarter century has passed and partial nitrification/anammox process for sewage treatment is still mainly in lab and pilot-scale research phase with few plants in operation. The main challenges for that are enrichment, grow and how to keep AnAOB in the reactor on low-strength wastewater treatment, such as in anaerobically treated domestic sewage. Another important aspect is need for continuous supply of nitrite and how to minimize nitrite consumption by others than anammox. In addition to that other minor control parameters play an important role, such as hydraulic and sludge retention time, dissolved oxygen, temperature, pH, etc. This paper presents a detailed review of essential process parameters and identifies gaps and solutions for effective implementation of the anammox process highlighting the different factors that suppress AnAOB growth, along with the aspects favouring activity and immobilization. Reactor start-up and operation, bacteria inhibition and conversion of emerging-pollutants is also investigated, with their effect on AnAOB and their removal. The main conclusions are the sustainability evaluation, which found that the process reduce the overall GHG emissions compared to conventional nitrogen removal processes; a possible microbial pathway that could be involved for simultaneous organics, nutrients and emerging-pollutants removal; and, finally, a novel concept of a three-stage treatment process in two up-flow anaerobic sludge blanket-based system is proposed.

Introduction Continuous soil monocropping typically disrupts microecological equilibrium, leading to reduced crop yield and quality degradation, whereas crop rotation often mitigates these issues. However, understanding of the microbial mechanism behind this rotation practice is still limited. Methods A three-year field experiment was conducted comparing tobacco continuous monocropping and tobacco-rice rotation. The bacterial community structure, assembly processes, and functional profiles were analyzed within three tobacco growing periods. Results While most soil physicochemical parameters, such as pH, total phosphorus, and available phosphorus, were not significantly different between the two systems, tobacco monoculture specifically resulted in elevated contents of total nitrogen and alkali-hydrolyzable nitrogen compared to tobacco-rice rotation systems. Although α-diversity also showed no significant differences between systems, bacterial community composition diverged significantly, with Proteobacteria, Acidobacteria, and Actinobacteria dominating. Deterministic processes governed community assembly, with βMNTD and βNTI exhibiting significant correlations with soil available nitrogen, phosphorus, potassium, and pH exclusively in the rotation system-contrasting sharply with the absence of such correlations in monoculture. Tobacco-rice rotation exhibited more complex co-occurrence networks anchored by 22 topological connector taxa than tobacco monocropping. Functionally, the rotation significantly suppressed nitrifying bacteria abundance, whereas monocropping enriched dark sulfide-oxidizing bacteria. Notably, despite the absence of significant overall differences in pathogen abundance between the two cropping systems, a high variation was observed of plant pathogen abundance in the vigorous growth stage of tobacco monocropping, which indicates that certain locations possess a considerably elevated susceptibility to potential disease epidemics. Discussion Compared to continuous monocropping, tobacco-rice rotation caused minimal shifts in soil α-diversity and physicochemical properties. However, our three years field study reveals that it profoundly restructured the composition and interaction networks of the soil bacterial community. This highlights the divergent impacts of cropping systems on the soil microbiome and indicates that the benefit of rotation may stem primarily from its ability to rewire microbial interactions, thereby alleviating continuous cropping obstacles.