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.

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.

Acidophilic partial nitrification (pH<6) facilitates ultra-efficient short-flow nitrogen transformation: Experimental validation and genomic insights.

Partial nitrification (PN) represents an energy-efficient bioprocess; however, it often confronts challenges such as unstable nitrite accumulation, nitrite oxidizing bacteria shocks, and slow reaction rate. This study established an acidophilic PN with self-sustained pH as low as 5.36.

Anammox granule destruction and reconstruction in a partial nitrification/anammox system under hydroxylamine stress.

Nitrite oxidizing bacteria (NOB) outcompeting anammox bacteria (AnAOB) poses a challenge to the practical implementation of the partial nitrification/anammox (PN/A) process for municipal wastewater. A granules-based PN/A bioreactor was operated for 260 d with hydroxylamine (NHOH) added halfway through. qPCR results detected the different amounts of NOB among granules and flocs and the dynamic succession during operation.

Advanced nitrogen removal from mature landfill leachate based on novel step-draining partial nitrification-denitrification and Anammox process: Significance of low volume exchange ratio.

To save external carbon source dosage and simplify NH to NO ratio control strategy, this study established a novel step-draining based partial nitrification-denitrification and Anammox (PND-AMX) system for advanced nitrogen removal from mature landfill leachate. Separation of partial nitrification and denitrification was realized based on step-draining, achieving 74.8 % nitrogen removal.

Continuous plug-flow anammox system for mature landfill leachate treatment: Key zone for anammox pathway.

This study established the one-stage partial nitrification coupled anammox and partial denitrification coupled anammox process in an anoxic/oxic continuous plug-flow system and operated for 465 days to treat mature landfill leachate. 97.9 %-98.

Anammox-mediated municipal solid waste leachate treatment: A critical review.

Municipal solid waste (MSW) leachate treatment through the anaerobic ammonium oxidation (anammox) process has received increasing attention due to less oxygen consumption, carbon source demand, and sludge production. The recent advances in anammox-mediated MSW leachate treatment are systematically reviewed. During MSW leachate treatment, the anammox technology could be flexibly combined with partial nitrification, partial denitrification, fermentation, and methane oxidation.

An Innovative Process for Mature Landfill Leachate and Waste Activated Sludge Simultaneous Treatment Based on Partial Nitrification, In Situ Fermentation, and Anammox (PNFA).

An innovative partial nitrification, in situ fermentation, and Anammox (PNFA) system was developed to achieve mature landfill leachate and waste activated sludge simultaneous treatment. Three separate sequencing batch reactors (SBRs) were used for partial nitrification (PN-SBR), integrated fermentation-denitrification (IFD-SBR), and partial nitrification-Anammox (PNA-SBR). After 200 days of continuous operation, a satisfactory nitrogen removal efficiency (NRE) of 99.

Development of a novel partial nitrification, fermentation-based double denitrification bioprocess (PN-F-Double/DN) to simultaneous treatment of mature landfill leachate and waste activated sludge.

Introducing fermentation technology into sewage treatment is a sustainable development concept, but future application still faces many challenges. A novel partial nitrification, fermentation-based double denitrification bioprocess (PN-F-Double/DN) was achieved in three separated SBR type reactors, simultaneously treating high ammonia (1766.6 mg/L) mature landfill leachate and external waste activated sludge (WAS, MLSS = 20.

Improving stability of mainstream Anammox in an innovative two-stage process for advanced nitrogen removal from mature landfill leachate.

This study presents an innovative mainstream Anammox based on multiple NO-N supplement pathways to treat actual mature landfill leachate over 180 days. Desirable effluent quality of 11.8 mg/L total nitrogen (TN) and nitrogen removal efficiency of 98.

Achieving synergetic treatment of sludge supernatant, waste activated sludge and secondary effluent for wastewater treatment plants (WWTPs) sustainable development.

A novel process that combines partial nitrification, fermentation and Anammox-partial denitrification (NFAD) was proposed to co-treat ammonia rich sludge supernatant (NH-N = 1194.1 mg/L), external WAS (MLSS = 22092.6 mg/L) and WWTP secondary effluent (NO-N = 58.

New insights into co-treatment of mature landfill leachate with municipal sewage via integrated partial nitrification, Anammox and denitratation.

As a low consumption and high efficiency process, Partial Nitrification-Anammox/denitratation (PNAD) was applied to co-treat mature landfill leachate with municipal sewage for 300 days. Specifically, ammonia (670.2 ± 63.

Advanced nitrogen removal from mature landfill leachate via partial nitrification-Anammox biofilm reactor (PNABR) driven by high dissolved oxygen (DO): Protection mechanism of aerobic biofilm.

A novel partial nitrification-Anammox biofilm reactor (PNABR) operated under high dissolved oxygen (DO) with pre-anoxic - aerobic - anoxic operational mode was developed for efficient denitrogenation from mature landfill leachate. With DO concentration gradually increasing to 4.03 ± 0.

A continuous-flow combined process based on partial nitrification-Anammox and partial denitrification-Anammox (PN/A + PD/A) for enhanced nitrogen removal from mature landfill leachate.

A novel continuous-flow combined process of partial nitrification, Anammox (PN/A) and partial denitrification-Anammox (PD/A) was established to achieve enhanced nitrogen removal from landfill leachate. The NH-N transformation rate and NO-N accumulation rate in the PN reactor reached 93.4% and 91.

Simultaneous Ammonium oxidation denitrifying (SAD) in an innovative three-stage process for energy-efficient mature landfill leachate treatment with external sludge reduction.

High-loaded ammonia and low-strength organics mature landfill leachate is not effectively treated by conventional biological processes. Herein, an innovative solution was proposed using a three-stage Simultaneous Ammonium oxidation Denitrifying (SAD) process. Firstly, ammonia (1760 ± 126 mg N/L) in wastewater was oxidized to nitrite in a partial nitrification sequencing batch reactor (PN-SBR).

Nitrite accumulation in comammox-dominated nitrification-denitrification reactors: Effects of DO concentration and hydroxylamine addition.

In this study, nitrite accumulation was investigated under different DO conditions and different hydroxylamine addition methods during the domestic wastewater treatment. Two sequencing batch reactors in parallel were operated under cyclic aerobic and anoxic conditions with the DO concentration of 2.0 and 4.

Novel insights into integrated fermentation and nitrogen removal by free nitrous acid (FNA) serving as treatment method.

Free nitrous acid (FNA) has only been studied as the pretreatment of waste activated sludge (WAS). Integrated fermentation and nitrogen removal using FNA as a primary means of treatment are seldom investigated. WAS fermentation was characterized under various FNA concentration.

Enhanced nitrogen removal from nitrate-rich mature leachate via partial denitrification (PD)-anammox under real-time control.

It is difficult to achieve high standard effluent through conventional nitrification-denitrification process treating mature leachate and the advanced treatment is usually required. This study proposed an economical process for enhancing nitrogen removal from nitrate-rich leachate which combined partial-denitrification and anammox (PD/A) in a SBR. Under the concentration of influent ammonia and nitrate of 47.

High-efficient nitrogen removal from mature landfill leachate and waste activated sludge (WAS) reduction via partial nitrification and integrated fermentation-denitritation process (PNIFD).

Biological nitrogen removal from mature landfill leachate is ineffective due to the extremely low carbon/nitrogen (C/N) ratio. Moreover, a large amount of waste activated sludge (WAS) is inevitably generated from WWTPs during the municipal sewage treatment process. In this study, an innovative process was developed to enhance nitrogen removal from low C/N (1:1) mature landfill leachate and to reduce the WAS during a 300-day operation.

Efficient step-feed partial nitrification, simultaneous Anammox and denitrification (SPNAD) equipped with real-time control parameters treating raw mature landfill leachate.

An innovative step-feed partial nitrification, simultaneous Anammox and denitrification (SPNAD), equipped with real-time control parameters, achieved efficient nitrogen removal from raw mature landfill leachate. The variables pH and ORP served as real time on-line parameters to flexibly control the durations of aerobic and anoxic. A nitrogen removal efficiency (NRE) of 98.

Effect of carbon source type on intracellular stored polymers during endogenous denitritation (ED) treating landfill leachate.

Glycogen accumulating organisms (GAOs) capable of storing organic compounds as polyhydroxyalkanoate (PHA) have been used for endogenous denitritation (ED), but the effect of carbon sources type on nitrogen removal performance of GAOs treating landfill leachate is unclear. In this study, a successful ED system treating landfill leachate (COD/NH4(+)-N (C/N): 4) without external carbon source addition was applied. The mature leachate with C/N of 1 was used as the feeding base solution, with acetate, propionate, and glucose examined as the carbon sources, and their effects on yields and compositions of PHA produced by GAOs were determined and associated with nitrogen removal performance.

Continuous-flow combined process of nitritation and ANAMMOX for treatment of landfill leachate.

Due to the difficulty in removing nitrogen from landfill leachate, a combined continuous-flow process of nitritation and anammox was applied to process mature leachate. The transformation rate of ammonia and nitrite accumulation ratio in A/O reactor were kept above 95% and 92% respectively through associated inhibition of free ammonia (FA) and free nitrous acid (FNA) to NOB. The total nitrogen volumetric load of anammox in an UASB reactor was brought up from 0.