Towards the application of mainstream low-carbon anammox wastewater treatment technologies: strategies, innovations, and prospects

Abstract

Enhancing nitrogen removal is a very active branch in municipal wastewater treatment research, toward this end, anammox technology is a sustainable solution. This review systematically outlines the strategies employed to enhance mainstream anammox performance, including nitrite accumulation and microbial enrichment based on partial nitrification coupled anammox and partial denitrification coupled anammox, developed to address the challenges of low ammonium content in wastewater, nitrate accumulation in the effluent, and the influence of organic matter. The characteristics and advantages of novel anammox-coupled processes, including partial nitrification and partial denitrification coupled anammox, endogenous partial denitrification coupled anammox, and denitrifying anaerobic methane oxic coupled anammox are also comprehensively discussed; these aim to ensure the highly efficient and stable operation of anammox under diverse wastewater conditions by constructing a composite biological nitrogen removal system based on anammox, supplemented by nitrification-denitrification and other processes. Additionally, a novel anammox application route including mainstream partial denitrification/anammox and absorption-biodegradation as well as sidestream partial nitrification/anammox is proposed, and its application pathway in conceptual wastewater treatment plants is outlined, aiming to foster the development of cost-effective, efficient, and energy-saving advanced wastewater treatment processes. Finally, prospects are presented that indicate the gaps in contemporary research and potential future research directions. Overall, this review provides a reference for treating municipal wastewater with anammox and sheds new light on related strategies and nitrogen removal mechanisms.

Graphical abstract

Keywords

mainstream anammox / municipal wastewater treatment / nitrogen removal / operation strategy / process innovation

References

[1] Li W , Li X , Zhang Q , Kao C , Hou X , Peng Y . Recent advances of partial anammox by controlling nitrite supply in mainstream wastewater treatment through step-feed mode. Science of the Total Environment, 2024, 912: 168965

[2] Firestone M , Kavlock R , Zenick H , Kramer M . The U. S. Environmental protection agency strategic plan for evaluating the toxicity of chemicals. Journal of Toxicology and Environmental Health Part B: Critical Reviews, 2010, 13(2–4): 139–162

[3] Water Quality Sewerage System Guidelines. Water Quality Australia Website, 2024

[4] Ren Z , Wang H , Zhang L , Du X , Huang B , Jin R . A Review of anammox-based nitrogen removal technology: from microbial diversity to engineering applications. Bioresource Technology, 2022, 363: 127896

[5] Mulder A , van de Graaf A A , Robertson L A , Kuenen J G . Anaerobic ammonium oxidation discovered in a denitrifying fluidized bed reactor. FEMS Microbiology Ecology, 1995, 16(3): 177–183

[6] Jiang C , Xu S , Wang R , Feng S , Zhou S , Wu S , Zeng X , Wu S , Zhuang X . Achieving efficient nitrogen removal from real sewage via nitrite pathway in a continuous nitrogen removal process by combining free nitrous acid sludge treatment and DO control. Water Research, 2019, 161: 590–600

[7] Pedrouso A , Río A V , Morales N , Vázquez-Padín J R , Campos J L , Méndez R , Mosquera-Corral A . Nitrite oxidizing bacteria suppression based on in-situ free nitrous acid production at mainstream conditions. Separation and Purification Technology, 2017, 186: 55–62

[8] Fenu A , Smolders S , Gussem K D , Weemaes M . Conflicting carbon footprint and energy saving in a side-stream anammox process. Biochemical Engineering Journal, 2019, 151: 107336

[9] Jiang M , Ji S , Wu R , Yang H , Li Y , Liu J . Exploiting refractory organic matter for advanced nitrogen removal from mature landfill leachate via anammox in an expanded granular sludge bed reactor. Bioresource Technology, 2023, 371: 128594

[10] Zhao K , Wang Y , Gao L , Chai B , Zhuang P , Kou X . Anammox in a biofilter reactor to treat wastewater of high strength nitrogen. Journal of Water Process Engineering, 2022, 49: 103169

[11] Lackner S , Gilbert E M , Vlaeminck S E , Joss A , Horn H , van Loosdrecht M C M . Full-scale partial nitritation/anammox experiences—an application survey. Water Research, 2014, 55: 292–303

[12] Wang G , Xu X , Zhou L , Wang C , Yang F . A pilot-scale study on the start-up of partial nitrification-anammox process for anaerobic sludge digester liquor treatment. Bioresource Technology, 2017, 241: 181–189

[13] Du R , Peng Y , Ji J , Shi L , Gao R , Li X . Partial denitrification providing nitrite: opportunities of extending application for anammox. Environment International, 2019, 131: 105001

[14] Gao R , Peng Y , Li J , Du R , Yang L , Wang M , Deng L . Nitrogen removal from low COD/TIN real municipal sewage by coupling partial denitrification with anammox in mainstream. Chemical Engineering Journal, 2021, 410: 128221

[15] Liu Q , Peng Y , Zhao Y , Zhao Q , Li X , Zhang Q , Sui J , Wang C , Li J . Excellent anammox performance driven by stable partial denitrification when encountering seasonal decreasing temperature. Bioresource Technology, 2022, 364: 128041

[16] Wu P , Chen J , Garlapati V K , Zhang X , Jenario F W V , Li X , Liu W , Chen C , Aminabhavi M T , Zhang X . Novel insights into anammox-based processes: a critical review. Chemical Engineering Journal, 2022, 444: 136534

[17] Qiu S , Li Z , Hu Y , Shi L , Liu R , Shi L , Chen L , Zhan X . What’s the best way to achieve successful mainstream partial nitritation-anammox application. Critical Reviews in Environmental Science and Technology, 2020, 51(10): 1045–1077

[18] Gu X , Huang Y , Hu Y , Gao J , Zhang M . Inhibition of nitrite-oxidizing bacteria in automatic recycling PN/ANAMMOX under mainstream conditions. Bioresource Technology, 2021, 342: 125935

[19] Zhang C , Zhang M , Yang H , Cai W , Wu J . Single-stage partial nitrification/anammox process performance restoration by bio-augmenting nitrifiers with or without nitrite oxidizing bacteria suppression. Journal of Water Process Engineering, 2024, 57: 104608

[20] Lei Z , Wang L , Wang J , Yang S , Hou Z , Wang X , Chen R . Partial-nitritation of low-strength anaerobic effluent: a moderate-high dissolved oxygen concentration facilitates ammonia-oxidizing bacteria disinhibition and nitrite-oxidizing bacteria suppression. Science of the Total Environment, 2021, 770: 145337

[21] Shi L , Du R , Peng Y . Achieving partial denitrification using carbon sources in domestic wastewater with waste-activated sludge as inoculum. Bioresource Technology, 2019, 283: 18–27

[22] Cao S , Li B , Du R , Ren N , Peng Y . Nitrite production in a partial denitrifying upflow sludge bed (USB) reactor equipped with gas automatic circulation (GAC). Water Research, 2016, 90: 309–316

[23] Liu H , Dong W , Zhao Z , Wang H , Hou Z , Li Y , Chen S , Xiao D . Anammox-based technologies for municipal sewage nitrogen removal: advances in implementation strategies and existing obstacles. Journal of Water Process Engineering, 2023, 55: 104090

[24] Chen X , Liu L , Bi Y , Meng F , Wang D , Qiu C , Yu J , Wang S . A review of anammox metabolic response to environmental factors: characteristics and mechanisms. Environmental Research, 2023, 223: 115464

[25] Wu Q , Wang X , Li H , Huang D , Huang B , Jin R , Fan N . Perturbation and mechanism of non-antibiotic drug in regulating resistome and metabolome of anammox consortia: an overlooked and underrated cause of multiresistance. Chemical Engineering Journal, 2023, 475: 146325

[26] Zhang Y , Sun Q , Zhao B , Li J , Zhang X , Zhang B , Liu B . Response of anammox to long-term stress of Ni(II): nitrogen removal, microbial products and microbial community. Biochemical Engineering Journal, 2023, 200: 109112

[27] Jin P , Li B , Mu D , Li X , Peng Y . High-efficient nitrogen removal from municipal wastewater via two-stage nitritation/anammox process: long-term stability assessment and mechanism analysis. Bioresource Technology, 2019, 271: 150–158

[28] Zhang M , Wang S , Ji B , Liu Y . Towards mainstream deammonification of municipal wastewater: partial nitrification-anammox versus partial denitrification-anammox. Science of the Total Environment, 2019, 692: 393–401

[29] Wang Z , Zheng M , Duan H , Yuan Z , Hu S . A 20-year journey of partial nitritation and anammox (PN/A): from sidestream toward mainstream. Environmental Science & Technology, 2022, 56(12): 7522–7531

[30] Choi D , Lee C , Jung J . Innovative start-up strategies for single-stage deammonification with conventional activated sludge: results of a pilot-scale demonstration. Bioresource Technology, 2020, 309: 123423

[31] Cao Y , Kwok B , Loosdrecht M , Daigger G , Png H , Long W , Eng O . The influence of dissolved oxygen on partial nitritation/anammox performance and microbial community of the 200,000 m³/d activated sludge process at the Changi water reclamation plant (2011 to 2016). Water Science & Technology, 2018, 78(3): 634–643

[32] Gu J , Zhang M , Liu Y . A review on mainstream deammonification of municipal wastewater: novel dual step process. Bioresource Technology, 2020, 299: 122674

[33] Wan J , Gu J , Zhao Q , Liu Y . COD capture: a feasible option towards energy self-sufficient domestic wastewater treatment. Scientific Reports, 2016, 6(1): 25054

[34] Qiu S , Wang L , Chen Z , Yang M , Yu Z , Ge S . An integrated mainstream and sidestream strategy for overcoming nitrite oxidizing bacteria adaptation in a continuous plug-flow nutrient removal process. Bioresource Technology, 2021, 319: 124133

[35] Ma Y , Peng Y , Wang S , Yuan Z , Wang X . Achieving nitrogen removal via nitrite in a pilot-scale continuous pre-denitrification plant. Water Research, 2009, 43(3): 563–572

[36] Ge S , Peng Y , Qiu S , Zhu A , Ren N . Complete nitrogen removal from municipal wastewater via partial nitrification by appropriately alternating anoxic/aerobic conditions in a continuous plug-flow step feed process. Water Research, 2014, 55: 95–105

[37] Soliman M , Eldyasti A . Ammonia-oxidizing bacteria (AOB): opportunities and applications—a review. Reviews in Environmental Science and Biotechnology, 2018, 17(2): 285–321

[38] Hou X , Li X , Zhu X , Li W , Kao C , Peng Y . Advanced nitrogen removal from municipal wastewater through partial nitrification-denitrification coupled with anammox in step-feed continuous system. Bioresource Technology, 2024, 391: 129967

[39] Dytczak M A , Londry K L , Oleszkiewicz J A . Activated sludge operational regime has significant impact on the type of nitrifying community and its nitrification rates. Water Research, 2008, 42(8): 2320–2328

[40] Gilbert E M , Agrawal S , Schwartz T , Horn H , Lackner S . Comparing different reactor configurations for partial nitritation/anammox at low temperatures. Water Research, 2015, 81: 92–100

[41] Xu Z , Zhang L , Gao X , Peng Y . Optimization of the intermittent aeration to improve the stability and flexibility of a mainstream hybrid partial nitrification-anammox system. Chemosphere, 2020, 261: 127670

[42] Le L , Nghiem L D , Bui X , Jahng D . Improve nitrogen removal of the biofilm single-stage PN/A process by optimizing the intermittent aeration strategy. Environmental Technology & Innovation, 2023, 30: 103078

[43] Hulle S W V , Volcke E I , Teruel J L , Donckels B , van Loosdrecht M C , Vanrolleghem A P . Influence of temperature and pH on the kinetics of the sharon nitritation process. Journal of Chemical Technology and Biotechnology, 2007, 82(5): 471–480

[44] Wang L , Kang X , Liu Y , Huang X . Free ammonia-free nitrous acid based partial nitrification in sequencing batch membrane aerated biofilm reactor. Water Research, 2023, 241: 120168

[45] Ma B , Yang L , Wang Q , Yuan Z , Wang Y , Peng Y . Inactivation and adaptation of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria when exposed to free nitrous acid. Bioresource Technology, 2017, 245: 1266–1270

[46] Yun H , Kim D . Nitrite accumulation characteristics of high strength ammonia wastewater in an autotrophic nitrifying biofilm reactor. Journal of Chemical Technology and Biotechnology, 2003, 78(4): 377–383

[47] Duan H , Ye L , Lu X , Yuan Z . Overcoming nitrite oxidizing bacteria adaptation through alternating sludge treatment with free nitrous acid and free ammonia. Environmental Science & Technology, 2019, 53(4): 1937–1946

[48] Wang Z , Zhang S , Zhang L , Wang B , Liu W , Ma S , Peng Y . Restoration of real sewage partial nitritation-anammox process from nitrate accumulation using free nitrous acid treatment. Bioresource Technology, 2018, 251: 341–349

[49] Xu G , Zhou Y , Yang Q , Lee Z M , Gu J , Lay W , Cao Y , Liu Y . The challenges of mainstream deammonification process for municipal used water treatment. Applied Microbiology and Biotechnology, 2015, 99(6): 2485–2490

[50] Cao Y , Mark M C M , Daigger G T . Mainstream partial nitritation-anammox in municipal wastewater treatment: status, bottlenecks, and further studies. Applied Microbiology and Biotechnology, 2017, 101(4): 1365–1383

[51] Hellinga C , Schellen A A J C , Mulder J W , van Loosdrecht M C M , Heijnen J J . The sharon process: an innovative method for nitrogen removal from ammonium-rich waste water. Water Science and Technology, 1998, 37(9): 135–142

[52] Li J , Zhang L , Peng Y , Yang S , Wang X , Li X , Zhang Q . NOB suppression in partial nitritation-anammox (PNA) process by discharging aged flocs: performance and microbial community dynamics. Chemosphere, 2019, 227: 26–33

[53] Arora A S , Nawaz A , Qyyum M A , Ismail S , Aslam M , Tawfik A , Yun C M , Lee M . Energy saving anammox technology-based nitrogen removal and bioenergy recovery from wastewater: inhibition mechanisms, state-of-the-art control strategies, and prospects. Renewable & Sustainable Energy Reviews, 2021, 135: 110126

[54] Gong S , Qin Y , Zheng S , Lu T , Yang X , Zeng M , Zhou H , Chen J , Huang W . The rapid start-up of CANON process through adding partial nitration sludge to ANAMMOX system. Journal of Environmental Management, 2023, 338: 117821

[55] Zhu G , Wang S , Ma B , Wang X , Zhou J , Zhao S , Liu R . Anammox granular sludge in low-ammonium sewage treatment: not bigger size driving better performance. Water Research, 2018, 142: 147–158

[56] Malovanyy A , Trela J , Plaza E . Mainstream wastewater treatment in integrated fixed film activated sludge (IFAS) reactor by partial nitritation/anammox process. Bioresource Technology, 2015, 198: 478–487

[57] Pedrouso A , Trela J , del Rio A V , Mosquera-Corral A , Plaza E . Performance of partial nitritation-anammox processes at mainstream conditions in an IFAS system. Journal of Environmental Management, 2019, 250: 109538

[58] Wu J , Kong Z , Luo Z , Qin Y , Rong C , Wang T , Hanaoka T , Sakemi S , Li Y . A successful start-up of an anaerobic membrane bioreactor (AnMBR) coupled mainstream partial nitritation-anammox (PN/A) system: a pilot-scale study on in-situ NOB elimination, AnAOB growth kinetics, and mainstream treatment performance. Water Research, 2021, 207: 117783

[59] Han X , Zhang L , Yuan Y , Zhang Q , Peng Y . Anaerobic starvation realizes partial nitrification and starts anammox bacteria self-enrichment in mainstream municipal sewage treatment in a low filling ratio sequencing batch reactor. Bioresource Technology, 2023, 387: 129505

[60] Rong C , Luo Z , Wang T , Qin Y , Wu J , Guo Y , Hu Y , Kong Z , Li Y . Biomass retention and microbial segregation to offset the impacts of seasonal temperatures for a pilot-scale integrated fixed-film activated sludge partial nitritation-anammox (IFAS-PN/A) treating anaerobically pretreated municipal wastewater. Water Research, 2022, 225: 119194

[61] Yang S , Peng Y , Zhang L , Zhang Q , Li J , Wang X . Autotrophic nitrogen removal in an integrated fixed-biofilm activated sludge (IFAS) reactor: anammox bacteria enriched in the flocs have been overlooked. Bioresource Technology, 2019, 288: 121512

[62] Li L , Ling Y , Wang H , Chu Z , Yan G , Li Z , Wu T N . H₂O emission in partial nitritation-anammox process. Chinese Chemical Letters, 2020, 31(1): 28–38

[63] Qiu S , Hu Y , Liu R , Sheng X , Chen L , Wu G , Hu H , Zhan X . Start up of partial nitritation-anammox process using intermittently aerated sequencing batch reactor: performance and microbial community dynamics. Science of the Total Environment, 2019, 647: 1188–1198

[64] Rathnayake R M L D , Oshiki M , Ishii S , Segawa T , Satoh H , Okabe S . Effects of dissolved oxygen and pH on nitrous oxide production rates in autotrophic partial nitrification granules. Bioresource Technology, 2015, 197: 15–22

[65] Su Q , Ma C , Domingo-Félez C , Kiil A S , Thamdrup B , Jensen M M , Smets B F . Low nitrous oxide production through nitrifier-denitrification in intermittent-feed high-rate nitritation reactors. Water Research, 2017, 123: 429–438

[66] Poh L S , Jiang X , Zhang Z , Liu Y , Ng W J , Zhou Y N . H₂O accumulation from denitrification under different temperatures. Applied Microbiology and Biotechnology, 2015, 99(21): 9215–9226

[67] Castro-Barros C M , Rodríguez-Caballero A , Volcke E I P , Pi M . Effect of nitrite on the N₂O and NO production on the nitrification of low-strength ammonium wastewater. Chemical Engineering Journal, 2016, 287: 269–276

[68] Ribera-Guardia A , Pi M . Distinctive NO and N₂O emission patterns in ammonia oxidizing bacteria: effect of ammonia oxidation rate, DO and pH. Chemical Engineering Journal, 2017, 321: 358–365

[69] Beaumont H J E , Lens S I , Reijnders W N M , Westerhoff H V , van Spanning R J M . Expression of nitrite reductase in Nitrosomonas europaea involves NsrR, a novel nitrite-sensitive transcription repressor. Molecular Microbiology, 2004, 54(1): 148–158

[70] Qiu S , Li Z , Hu Y , Yang Q , Chen L , Liu R , Zhan X N . H₂O generation via nitritation at different volumetric oxygen transfer levels in partial nitritation-anammox process. Journal of Cleaner Production, 2021, 293: 126104

[71] WuJXuTYanGHeCZhouG. Model predictive control of partial nitrification via nitrous oxide (N₂O) emission monitoring. Journal of Environmental Chemical Engineering, 2015, 3(44, Part A): 2857–2865

[72] Ye L , Ni B , Law Y , Byers C , Yuan Z . A novel methodology to quantify nitrous oxide emissions from full-scale wastewater treatment systems with surface aerators. Water Research, 2014, 48: 257–268

[73] Zhu Z , Zhang L , Li X , Zhang Q , Wang S , Peng Y . Robust nitrogen removal from municipal wastewater by partial nitrification anammox at ultra-low dissolved oxygen in a pure biofilm system. Bioresource Technology, 2023, 369: 128453

[74] Chen Y , Sun Y , Zhang J , Li J , Peng Y . A novel control strategy to strengthen nitrogen removal from domestic wastewater through eliminating nitrite oxidizing bacteria in a plug-flow process. Bioresource Technology, 2022, 350: 126856

[75] Wang J , Zhang S , Li J , Yang H . Municipal wastewater treatment via the two-stage partial nitrification-anammox (PN/A) process with gel immobilization. Journal of Water Process Engineering, 2022, 50: 103267

[76] Wan C , Yang X , Lee D , Liu X , Sun S . Partial nitrification using aerobic granule continuous-flow reactor: operations and microbial community. Journal of the Taiwan Institute of Chemical Engineers, 2014, 45(5): 2681–2687

[77] Zhao J , Dong X , Su H , Huang J , Liu Z , He P , Zhang D . Rapid start-up of PN/A process and efficient enrichment of functional bacteria: a novel aerobic-biofilm/anaerobic-granular nitrogen removal system (OANRS). Bioresource Technology, 2023, 380: 128944

[78] Wang Z , Peng Y , Li J , Liu J , Zhang Q , Li X , Zhang L . Rapid initiation and stable maintenance of municipal wastewater nitritation during the continuous flow anaerobic/oxic process with an ultra-low sludge retention time. Water Research, 2021, 197: 117091

[79] Gao R , Peng Y , Li J , Li X , Zhang Q , Deng L , Li W , Kao C . Nutrients removal from low C/N actual municipal wastewater by partial nitritation/anammox (PN/A) coupling with a step-feed anaerobic-anoxic-oxic (A/A/O) system. Science of the Total Environment, 2021, 799: 149293

[80] Wang J , Peng Y , Zhang Q , Su Y , Wang S , Li J . Advanced nitrogen removal in a single return anaerobic/aerobic/anoxic/aerobic (AnOAO) bioreactor treating municipal wastewater through hydroxylamine addition: performance and microbial community. Bioresource Technology, 2022, 351: 126926

[81] Gao R , Peng Y , Li J , Liu Y , Deng L , Li W , Kao C . Mainstream partial denitrification-anammox (PD/A) for municipal sewage treatment from moderate to low temperature: reactor performance and bacterial structure. Science of the Total Environment, 2022, 806: 150267

[82] Tao Y , Shi R , Li L , Xia S , Ning J , Xu W . Performance optimization and nitrogen removal mechanism of up-flow partial denitrification/anammox process. Journal of Environmental Management, 2023, 348: 119191

[83] Du R , Cao S , Wang S , Niu M , Peng Y . Performance of partial denitrification (PD)-ANAMMOX process in simultaneously treating nitrate and low C/N domestic wastewater at low temperature. Bioresource Technology, 2016, 219: 420–429

[84] Qian W , Ma B , Li X , Zhang Q , Peng Y . Long-term effect of pH on denitrification: high pH benefits achieving partial-denitrification. Bioresource Technology, 2019, 278: 444–449

[85] Cao S , Du R , Peng Y , Li B , Wang S . Novel two stage partial denitrification (PD)-anammox process for tertiary nitrogen removal from low carbon/nitrogen (C/N) municipal sewage. Chemical Engineering Journal, 2019, 362: 107–115

[86] Gao X , Zhang Q , An Z , Shao B , Peng Y . Municipal wastewater treatment with limited carbon sources: the significance and advantages of transformation from partial denitrification to partial nitrification coupling with anammox. Resources, Conservation and Recycling, 2023, 198: 107185

[87] HenkelJ. Oxygen transfer phenomena in activated sludge. Dissertation for Doctoral Degree. TU Darmstadt, 2010, 178

[88] Zhang Z , Zhang Y , Chen Y . Recent advances in partial denitrification in biological nitrogen removal: from enrichment to application. Bioresource Technology, 2020, 298: 122444

[89] Li J , Peng Y , Zhang L , Liu J , Wang X , Gao R , Pang L , Zhou Y . Quantify the contribution of anammox for enhanced nitrogen removal through metagenomic analysis and mass balance in an anoxic moving bed biofilm reactor. Water Research, 2019, 160: 178–187

[90] Du R , Cao S , Peng Y , Zhang H , Wang S . Combined partial denitrification (PD)-anammox: a method for high nitrate wastewater treatment. Environment International, 2019, 126: 707–716

[91] Ge S , Peng Y , Wang S , Lu C , Cao X , Zhu Y . Nitrite accumulation under constant temperature in anoxic denitrification process: the effects of carbon sources and COD/NO(3)-N. Bioresource Technology, 2012, 114: 137–143

[92] Liu X , Liu R , Yang Q , Cui B , Wu W , Zhao X , Wang Y . Achieving and control of partial denitrification in anoxic-oxic process of real municipal wastewater treatment plant. Bioresource Technology, 2021, 341: 125765

[93] Zhang M , Liu J , Liang J , Fan Y , Gu X , Wu J . Response of nitrite accumulation, sludge characteristic and microbial transition to carbon source during the partial denitrification (PD) process. Science of the Total Environment, 2023, 894: 165043

[94] Li W , Liu S , Zhang M , Zhao H , Zheng P . Oxidation of organic electron donor by denitratation: performance, pathway and key microorganism. Chemical Engineering Journal, 2018, 343: 554–560

[95] YuanYHuangYDengHShengXPanYLiX. Effect of C/N ratio on nitrite accumulation during denitrification process. Environmental Science, 2013, 34(4): 1416–1420 (in Chinese)

[96] Zhang M , Gao J , Liu Q , Fan Y , Zhu C , Liu Y , He C , Wu J . Nitrite accumulation and microbial behavior by seeding denitrifying phosphorus removal sludge for partial denitrification (PD): the effect of COD/NO3− ratio. Bioresource Technology, 2021, 323: 124524

[97] Zhang T , Cao J , Liu W , Liu G , Huang C , Luo J . Insights into integrated glycerol-driven partial denitrification-anaerobic ammonium oxidation system using bioinformatic analysis: the dominance of Bacillus spp. And the potential of nitrite producing via assimilatory nitrate reduction. Science of the Total Environment, 2023, 858: 160048

[98] Sharp R , Niemiec A , Khunjar W , Galst S , Deur A . Development of a novel deammonification process for cost effective separate centrate and main plant nitrogen removal. International Journal of Sustainable Development and Planning, 2017, 12(1): 11–21

[99] Du R , Cao S , Li B , Zhang H , Li X , Zhang Q , Peng Y . Step-feeding organic carbon enhances high-strength nitrate and ammonia removal via DEAMOX process. Chemical Engineering Journal, 2019, 360: 501–510

[100] Hao Z , Zhang L , Zhang Q , Peng Y , Shi L , Li Y . Rapidly achieving partial denitrification from nitrate wastewater in a alkaline fermentation system with primary sludge as inoculated sludge and fermentable substrate. Bioresource Technology, 2022, 360: 127528

[101] Kumar M , Lin J . Co-existence of anammox and denitrification for simultaneous nitrogen and carbon removal—strategies and issues. Journal of Hazardous Materials, 2010, 178(1): 1–9

[102] Cao S , Du R , Zhou Y . Coupling anammox with heterotrophic denitrification for enhanced nitrogen removal: a review. Critical Reviews in Environmental Science and Technology, 2021, 51(19): 2260–2293

[103] Du R , Liu Q , Peng Y , Cao S . Potential causes of partial-denitrification (PD) granular sludge breakdown under high nitrate loading rates. Science of the Total Environment, 2023, 862: 160749

[104] Zhang J , Miao Y , Zhang Q , Sun Y , Wu L , Peng Y . Mechanism of stable sewage nitrogen removal in a partial nitrification-anammox biofilm system at low temperatures: microbial community and EPS analysis. Bioresource Technology, 2020, 297: 122459

[105] Li W , Li X , Li J , Gao R , Kao C , Zhang Q , Hou X , Peng Y . Improved nitrogen removal performance by enhanced denitratation/anammox as decreasing temperature for municipal wastewater treatment. Resources, Conservation and Recycling, 2023, 190: 106869

[106] Du R , Cao S , Li B , Zhang H , Wang S , Peng Y . Synergy of partial-denitrification and anammox in continuously fed upflow sludge blanket reactor for simultaneous nitrate and ammonia removal at room temperature. Bioresource Technology, 2019, 274: 386–394

[107] Gao M , Zou X , Dang H , Guo H , Yao Y , Chen Y , Guo J , Liu Y . Enhancing anammox process at moderate temperature via employing anammox granular sludge reactor effluent addition. Process Safety and Environmental Protection, 2024, 182: 894–902

[108] Lin L , Zhang Y , Li Y . Enhancing start-up strategies for anammox granular sludge systems: a review. Science of the Total Environment, 2023, 902: 166398

[109] Adams M , Xie J , Kabore A J , Chang Y , Xie J , Guo M , Chen C . Research advances in anammox granular sludge: a review. Critical Reviews in Environmental Science and Technology, 2022, 52(5): 631–674

[110] Li J , Peng Y , Gao R , Yang L , Deng L , Zhao Q , Liu Q , Li X , Zhang L , Zhang L . Highly enriched anammox within anoxic biofilms by reducing suspended sludge biomass in a real-sewage A₂/O process. Water Research, 2021, 194: 116906

[111] Zhao Q , Chen K , Li J , Sun S , Jia T , Huang Y , Peng Y , Zhang L . Pilot-scale evaluation of partial denitrification/anammox on nitrogen removal from low COD/N real sewage based on a modified process. Bioresource Technology, 2021, 338: 125580

[112] Zhang X , Miao Y , Yu D , Qiu Y , Zhao J , Wang X . Culturing partial denitrification biofilm in side stream incubator with ordinary activated sludge as inoculum: one step closer to mainstream anammox upgrade. Bioresource Technology, 2022, 347: 126679

[113] Gao D , Li Y , Liang H . Biofilm carriers for anaerobic ammonium oxidation: mechanisms, applications, and roles in mainstream systems. Bioresource Technology, 2022, 353: 127115

[114] Du R , Cao S , Zhang H , Li X , Peng Y . Flexible nitrite supply alternative for mainstream anammox: advances in enhancing process stability. Environmental Science & Technology, 2020, 54(10): 6353–6364

[115] Sun Y , Cao J , Xu R , Zhang T , Luo J , Xue Z , Chen S , Wang S , Zhou H . Influence of C/N ratio and ammonia on nitrogen removal and N₂O emissions from one-stage partial denitrification coupled with anammox. Chemosphere, 2023, 341: 140035

[116] Al-Hazmi H E , Maktabifard M , Grubba D , Majtacz J , Hassan G K , Lu X , Piechota G , Mannina G , Bott C B , Mąkinia J . An advanced synergy of partial denitrification-anammox for optimizing nitrogen removal from wastewater: a review. Bioresource Technology, 2023, 381: 129168

[117] Du R , Peng Y , Cao S , Wang S , Niu M . Characteristic of nitrous oxide production in partial denitrification process with high nitrite accumulation. Bioresource Technology, 2016, 203: 341–347

[118] Wang Z , Zhang L , Zhang F , Jiang H , Ren S , Wang W , Peng Y . 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. Bioresource Technology, 2020, 297: 122483

[119] Zhang L , Zhang Q , Li X , Jia T , Wang S , Peng Y . Enhanced nitrogen removal from municipal wastewater via a novel combined process driven by partial nitrification/anammox (PN/A) and partial denitrification/anammox (PD/A) with an ultra-low hydraulic retention time (HRT). Bioresource Technology, 2022, 363: 127950

[120] Jin R C , Yang G F , Yu J J , Zheng P . The inhibition of the anammox process: a review. Chemical Engineering Journal, 2012, 197: 67–79

[121] Zhao J , Wang X , Li X , Jia S , Wang Q , Peng Y . Improvement of partial nitrification endogenous denitrification and phosphorus removal system: balancing competition between phosphorus and glycogen accumulating organisms to enhance nitrogen removal without initiating phosphorus removal deterioration. Bioresource Technology, 2019, 281: 382–391

[122] Shang T , Zhu X , Gong X , Guo J , Li X , Zhang Q , Peng Y . Efficient nitrogen removal in a total floc sludge system from domestic wastewater with low C/N: high anammox nitrogen removal contribution driven by endogenous partial denitrification. Bioresource Technology, 2023, 378: 128995

[123] Feng Y , Luo S , Zhang Y , Wang S , Peng Y . Enhanced nutrient removal from mainstream sewage via denitrifying dephosphatation, endogenous denitrification and anammox in a novel continuous flow process. Bioresource Technology, 2022, 351: 127003

[124] Zhao Q , Peng Y , Li J , Gao R , Jia T , Deng L , Du R . Sustainable upgrading of biological municipal wastewater treatment based on anammox: from microbial understanding to engineering application. Science of the Total Environment, 2022, 813: 152468

[125] Feng Y , Wang S , Peng Y . Stable nitrogen removal in the novel continuous flow anammox system under deteriorated partial nitrification: significance and superiority of the anaerobic-oxic-anoxic–oxic operation mode. Bioresource Technology, 2022, 361: 127693

[126] He Z , Geng S , Shen L , Lou L , Zheng P , Xu X , Hu B . The short- and long-term effects of environmental conditions on anaerobic methane oxidation coupled to nitrite reduction. Water Research, 2015, 68: 554–562

[127] Zhu G , Jetten M S M , Kuschk P , Ettwig K F , Yin C . Potential roles of anaerobic ammonium and methane oxidation in the nitrogen cycle of wetland ecosystems. Applied Microbiology and Biotechnology, 2010, 86(4): 1043–1055

[128] Holler T , Widdel F , Knittel K , Amann R , Kellermann M Y , Hinrichs K U , Teske A , Boetius A , Wegener G . Thermophilic anaerobic oxidation of methane by marine microbial consortia. ISME Journal, 2011, 5(12): 1946–1956

[129] Ma B , Wang S , Cao S , Miao Y , Jia F , Du R , Peng Y . Biological nitrogen removal from sewage via anammox: recent advances. Bioresource Technology, 2016, 200: 981–990

[130] Lu P , Liu T , Ni B J , Guo J , Yuan Z , Hu S . Growth kinetics of candidatus ‘methanoperedens nitroreducens’ enriched in a laboratory reactor. Science of the Total Environment, 2019, 659: 442–450

[131] Guerrero-Cruz S , Stultiens K , van Kessel M A H J , Versantvoort W , Jetten M S M , den Camp H J M O , Kartal B . Key physiology of a nitrite-dependent methane-oxidizing enrichment culture. Applied and Environmental Microbiology, 2019, 85(8): e00124–e19

[132] Liu C , Liu T , Zheng X , Meng J , Chen H , Yuan Z , Hu S , Guo J . Rapid formation of granules coupling n-DAMO and anammox microorganisms to remove nitrogen. Water Research, 2021, 194: 116963

[133] Nie W , Xie G , Ding J , Peng L , Lu Y , Tan X , Yue H , Liu B , Ren N . Operation strategies of N-DAMO and anammox process based on microbial interactions for high rate nitrogen removal from landfill leachate. Environment International, 2020, 139: 105596

[134] Zhang Z , Li D , Zhou C , Huang X , Chen Y , Wang S , Liu G . Enhanced nitrogen removal via partial nitrification/denitrification coupled anammox using three stage anoxic/oxic biofilm process with intermittent aeration. Water Research, 2024, 255: 121491

[135] Gao R , Peng Y , Li J , Zhang Q , Li X , Deng L , Li W , Kao C . Improving performance and efficiency of partial anammox by coupling partial nitrification and partial denitrification (PN/A-PD/A) to treat municipal sewage in a step-feed reactor. Bioresource Technology, 2021, 341: 125804

[136] Cui H , Zhang L , Zhang Q , Li X , Huang Y , Peng Y . Advanced nitrogen removal from low C/N municipal wastewater by combining partial nitrification-anammox and endogenous partial denitrification-anammox (PN/A-EPD/A) process in a single-stage reactor. Bioresource Technology, 2021, 339: 125501

[137] Ma B , Liang Y , Zhang Y , Wei Y . Achieving advanced nitrogen removal from low-carbon municipal wastewater using partial-nitrification/anammox and endogenous partial-denitrification/anammox. Bioresource Technology, 2023, 383: 129227

[138] Meng H , Zhang X , Zhou Z , Luo L , Lan W , Lin J , Li X , Gu J . Simultaneous occurrence and analysis of both anammox and n-damo bacteria in five full-scale wastewater treatment plants. International Biodeterioration & Biodegradation, 2021, 156: 105112

[139] Lu Y , Liu T , Hu S , Yuan Z , Dwyer J , Akker B V D , Lloyd J , Guo J . Coupling partial nitritation, anammox and n-DAMO in a membrane aerated biofilm reactor for simultaneous dissolved methane and nitrogen removal. Water Research, 2024, 255: 121511

[140] Zhang L , Jiang L , Zhang J , Li J , Peng Y . Enhancing nitrogen removal through directly integrating anammox into mainstream wastewater treatment: advantageous, issues and future study. Bioresource Technology, 2022, 362: 127827

[141] Zhang X , Zhang X , Chen J , Wu P , Yang Z , Zhou L , Zhu Z , Wu Z , Ruth G . A critical review of improving mainstream anammox systems: based on macroscopic process regulation and microscopic enhancement mechanisms. Environmental Research, 2023, 236: 116770

[142] Wang H , Fan Y , Zhou M , Liu J , Li X , Wang Y . Metagenomics insight into the long-term effect of ferrous ions on the mainstream anammox system. Environmental Research, 2023, 238: 117243

[143] Zuo F , Yue W , Gui S , Sui Q , Wei Y . Resilience of anammox application from sidestream to mainstream: a combined system coupling denitrification, partial nitritation and partial denitrification with anammox. Bioresource Technology, 2023, 374: 128783

[144] Izadi P , Izadi P , Eldyasti A . Towards mainstream deammonification: comprehensive review on potential mainstream applications and developed sidestream technologies. Journal of Environmental Management, 2021, 279: 111615

[145] Cao S , Koch K , Duan H , Wells G F , Ye L , Zhao Y , Du R . In a quest for high-efficiency mainstream partial nitritation-anammox (PN/A) implementation: one-stage or two-stage. Science of the Total Environment, 2023, 883: 163540

[146] Wang L , Gu W , Liu Y , Liang P , Zhang X , Huang X . Challenges, solutions and prospects of mainstream anammox-based process for municipal wastewater treatment. Science of the Total Environment, 2022, 820: 153351

Competing interests

The authors declare that they have no competing interests.

Acknowledgements

This work was supported by the Gansu Provincial Science and Technology Program (Technology Innovation Guidance Program)-East-West Science and Technology Collaboration Special Project (24CXNA029), Lanzhou Science and Technology Project (2024-8-39), Tianyou Youth Talent Lift Program of Lanzhou Jiaotong University, Lanzhou Jiaotong University Gansu Provincial Key Laboratory Open Subjects (2023047), Lanzhou Jiaotong University-Southwest Jiaotong University Joint Innovation Fund Project (LH2024020), Gansu Provincial Association for Science and Technology Enterprise Technology Innovation Project (GXHQY20240328-19).

RIGHTS & PERMISSIONS

2025 Higher Education Press