Multi-omics reveals mechanism of hydroxylamine-enhanced ultimate nitrogen removal in pilot-scale anaerobic/aerobic/anoxic system.

Hydroxylamine (HA) dosing is an effective strategy for promoting partial nitrification (PN); however, its impact on endogenous denitrification remains underexplored. In this study, long-term continuous HA dosing (1.4 mg/L) was introduced for over 110 days in a pilot-scale anaerobic/aerobic/anoxic (AOA) system treating municipal wastewater (66.

Unraveling rapid start-up and stable maintenance of partial nitrification in domestic wastewater under high dissolved oxygen.

Partial nitrification (PN), is a promising nitrogen removal technology in wastewater treatment. Contrary to the dogma that low dissolved oxygen (DO) is more conducive to achieving PN, this study successfully established PN within 7 days under high DO conditions (> 6 mg/L). Ultra-stable PN was maintained over 143 days with an average nitrite accumulation ratio of 98 % treating real domestic wastewater.

Acidophilic partial nitrification rapid startup and robustness validation for municipal wastewater treatment: Operation performance and microorganism insights.

Acidophilic partial nitrification (a-PN) is a promising short-flow nitrogen conversion biotechnology, but achieving a rapid startup remains a significant challenge. This study explored strategies for starting up a-PN in real municipal wastewater treatment using sequencing batch reactors (SBRs). The influent alkalinity-to-NH molar ratio was maintained at 0.

Metagenomic insights into nitrite accumulation in sulfur-based denitrification systems utilizing different electron donors: Functional microbial communities and metabolic mechanisms.

Sulfur-based autotrophic denitrification (SADN) offers new pathway for nitrite supply. However, sequential transformation of nitrogen and sulfur forms, and the functional microorganisms driving nitrite accumulation in SADN with different reduced inorganic sulfur compounds (RISCs), remain unclear. Desirable nitrite accumulation was achieved using elemental sulfur (S-group), sulfide (S-group) and thiosulfate (SO-group) as electron donors.

Refining Metal-Free Carbon Nanoreactors through Electronic and Geometric Comodification for Boosted HO Electrosynthesis toward Efficient Water Decontamination.

Hydrogen peroxide (HO) electrosynthesis using metal-free carbon materials via the 2e oxygen reduction pathway has sparked considerable research interest. However, the scalable preparation of carbon electrocatalysts to achieve satisfactory HO yield in acidic media remains a grand challenge. Here, we present the design of a carbon nanoreactor series that integrates precise O/N codoping alongside well-regulated geometric structures targeting high-efficiency electrosynthesis of HO.

Pilot-scale implementation of mainstream anammox for municipal wastewater treatment against cold temperature.

Applying anammox to municipal wastewater treatment promises enormous energy and resource savings; however, seasonally cold conditions pose a considerable challenge, impeding its future applications towards non-tropical regions. In this study, we establish a pilot-scale wastewater treatment plant (50 m/d) in northern China and implement the partial denitrification coupling anammox process on actual municipal wastewater. Despite seasonal cooling, the nitrogen removal efficiency remains high, ranging from 75.

Novel mixotrophic denitrification biofilter for efficient nitrate removal using dual electron donors of polycaprolactone and thiosulfate.

A novel mixotrophic denitrification biofilter for nitrate removal using polycaprolactone and thiosulfate (MD-PT) as electron donors was investigated. MD-PT achieved high nitrate removal efficiency of approximately 99.8 %.

Achieving efficient anammox contribution and the enrichment of functional bacteria in partial denitrification/anammox system: Performance, microbial evolution and correlation analysis.

The primary challenge of applying partial denitrification/anammox (PD/A) to municipal wastewater treatment lied in the enrichment of functional bacteria with a considerable autotrophic nitrogen removal performance. The results showed influent NO-N: NH-N, reaction time and temperature would influence anammox nitrogen removal contribution. N isotopic tracing technology further revealed the average anammox contribution rate was up to 94.

Enhancing anammox bacteria enrichment in integrated fixed-film activated sludge partial nitritation/anammox process via floc retention control.

A promising technology for partial nitritation/anammox (PN/A) processes to treat ammonium wastewater is integrated fixed-film activated sludge (IFAS). For practical applications, achieving efficient enrichment of anammox bacteria (AnAOB) remains a challenge. In this study, membranes were temporarily used to separate solid and liquid components to induce changes in the mixed liquor suspended solids of the flocs.

Predicting aeration time and nitrite accumulation rate variations for Partial Nitritation: A model incorporating nitrogen oxidation rate dynamics.

This study aimed to develop a two-step nitrification model to predict variations in aeration time and nitrite accumulation rate (NAR) under fluctuating operational conditions in mainstream partial nitritation (PN) processes. Lab-scale sequencing batch reactors (SBRs) were used to evaluate the ammonia oxidation rate (AOR) and nitrite oxidation rate (NOR) under different solids retention times (SRT) (10, 15, 20, 30, and 50 days) and total volumetric nitrogen loadings (TVNL) (20-60 mg N/L per cycle). A static model was developed to predict consistent AOR and NOR values in the steady state, whereas a dynamic model was established to capture the growth dynamics of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) under unsteady-state conditions.

Continuous self-circulating up-flow granular sludge fluidized bed process treating low-strength real municipal wastewater at high hydraulic loads.

Conditions conducive to aerobic granular sludge (AGS) growth and maintenance are very difficult to realize in continuous-flow biological treatment processes. This study conducted a continuous-flow self-circulating up-flow granular sludge fluidized bed (Zier process) treating real urban wastewater approximately one year. The substantial self-circulating multiple times (R, 8-15 times) and up-flow velocity (8-15 m/h) generated by aeration, the only power equipment in Zier process, facilitated pollutant removal, particle granulation and stabilization.

Feasibility of double nitrite supply through partial nitrification and partial denitrification driven by sludge fermentation.

Challenges in obtaining stable nitrite have impeded the use of anammox in municipal wastewater treatment. This study explored the feasibility of using sludge fermentation products as carbon source and selective nitrification inhibitor to supply nitrite via partial nitrification (PN) and partial denitrification (PD). PD was initiated within 15 days, achieving nitrite transformation rate of over 90 % with a carbon/nitrogen ratio of 3 and a reaction time of 0.

Novel control strategy employing anaerobic/aerobic/anoxic/aerobic/anoxic mode to enhance endogenous denitrification and anammox for municipal wastewater treatment.

Anaerobic/Aerobic/Anoxic (AOA) process utilizes endogenous denitrification to remove nitrogen. However, low endogenous denitrification activity critically restricts its application owing to insufficient carbon sources. In this study, a novel control strategy employing anaerobic/aerobic/anoxic/aerobic/anoxic (AOAOA) mode was introduced to treat low Carbon/Nitrogen (C/N) ratio municipal wastewater over 262 days.

Achieving advanced nitrogen removal with anammox and endogenous partial denitrification driven by efficient hydrolytic fermentation of slowly-biodegradable organic matter.

Anammox-based processes are pivotal for elevating nitrogen removal efficiency in municipal wastewater treatment. This study established a novel HF-EPDA system combined in-situ hydrolytic fermentation (HF) with endogenous partial denitrification (EPD) and anammox. Slowly-biodegradable organic matter (SBOM) was degraded and transformed into endogenous polymers for driving production of sufficient nitrite by EPD, further promoted the nitrogen removal via anammox process.

Pathways of inhibition of filamentous sludge bulking by slowly biodegradable organic compounds.

The organic compound composition of wastewater, serves as a crucial indicator for the operational performance of activated sludge processes and has a major influence on the development of filamentous bulking in activated sludge. This study focused on the impact of typical soluble and slowly-biodegradable organic compounds, investigating the pathways through which these substrates affect the occurrence of filamentous bulking in systems operated under both high- and low-oxygen conditions. Results showed that slowly-biodegradable organic compounds lead to a concentrated distribution of microorganisms within flocs, with inward growth of filamentous bacteria.

Advanced N removal from low C/N sewage via a plug-flow anaerobic/oxic/anoxic (AOA) process: Intensification through partial nitrification, endogenous denitrification, partial denitrification, and anammox (PNEnD/A).

Achieving low-cost advanced nitrogen (N) removal from municipal wastewater treatment plants (WWTPs) remains a challenge. A plug-flow anaerobic/oxic/anoxic (AOA) system with a mixtures bypass (MBP) integrating partial nitrification (PN), endogenous carbon denitrification (EnD), partial denitrification (PD), and anaerobic ammonium oxidation (Anammox), was constructed to treat actual sewage with a low C/N ratio. The effluent concentrations and removal efficiency of total inorganic nitrogen (TIN) during stable operation were 2.

Saturated dissolved oxygen-driven high-rate and ultrastable partial nitrification in municipal wastewater.

Achieving stable and high-rate partial nitrification (PN) remains a worldwide technical conundrum in low-strength mainstream conditions. This study successfully achieved ultrarapid mainstream PN within 8 days under a saturated dissolved oxygen (DO) supply strategy, reaching a record-breaking PN rate of over 1.0 kg N m d treating municipal wastewater.

Genomic synergistic efficient carbon fixation and nitrogen removal induced by excessive inorganic carbon in the anammox-centered coupling system.

Given the significance of HCO for autotrophic anammox bacteria (AnAOB), excessive HCO was always provided in anammox-related systems and engineering applications. However, its impact mechanism on anammox process at genome-level remains unknown. This study firstly established an anammox-centered coupling system that entails heterotrophic partial denitrification (PD) and hydrolytic acidification (A-PDHA) fed mainly with inorganic carbon (high HCO concentration and low C/N ratio).

Enhancing Fenton-like reaction mediating performance of covalent organic frameworks through porosity modification.

Covalent organic framework (COF) catalytic photocatalysts mediating Fenton-like reactions have been applied to the treatment of organic dyes in printing and dyeing wastewater. However, the photocatalytic performance of original COF is often unsatisfactory. This study investigated the impact of porosity modification strategies on the performance of COF photocatalysts in mediating the removal of organic dyes via Fenton-like reaction.

Enhancing collaboration of anammox with heterotrophic microbes mediated selectively by iron of different valences: Activities balance, metabolic mechanism, and functional genes regulation.

The partial denitrification/anammox (PD/A) process is receiving increasing attention due to its cost-effectiveness advantages. However, effective strategies to alleviate organic matter inhibition and promote anammox activity have been proven to be a big challenge. This study investigated the effects of three types of iron (nano zero-valent iron (nZVI), Fe(II), and Fe(III)) on the PD/A process.

Integrated process of Tetrasphaera-dominated in-situ waste activated sludge fermentation, biological phosphorus removal and endogenous denitrification in single reactor for treatment of wastewater with limited carbon sources.

An integrated process of sludge in-situ fermentation, biological phosphorus removal and endogenous denitrification (ISFPR-ED) was developed to treat low ratio of chemical oxygen demand to nitrogen (COD/N) wastewater and waste activated sludge (WAS) in a single reactor. Nutrient removal and WAS reduction were achieved due to Tetrasphaera-dominated sludge fermentation provided organic carbon in extending the anaerobic duration. The WAS reduction efficiency, effluent orthophosphate (PO-P) and total inorganic nitrogen reached 28.

Novel Anoxic-Anaerobic-Oxic process successfully enriched anammox bacteria under actual municipal wastewater.

Anaerobic ammonia oxidation (Anammox) exhibits promise for wastewater treatment,but the enrichment of anammox bacteria (AnAOB) in municipal wastewater treatment plants is a significant challenge. This study constructed a novel Anoxic-Anaerobic-Oxic (AAnO) process with a pure biofilm anoxic zone fed with actual fluctuating municipal wastewater and operated for six months to enrich AnAOB at ambient temperature. High-throughput sequencing (HTS), qPCR, and fluorescence in situ hybridization showed that AnAOB were successfully enriched in the anoxic biofilms, reaching 1.

Long-term effect of fine particulate matter constituents on reproductive hormones homeostasis in women attending assisted reproductive technologies: A population-based longitudinal study.

Fine particulate matter (PM) may disrupt women's reproductive hormones, posing potential reproductive risks. However, the exact compositions of PM responsible for these effects remain unclear. Our investigation explored the long-term impacts of PM constituents on reproductive hormones, based on a large longitudinal assisted reproductive cohort study in Anhui, China.