Acknowledgment to the Reviewers of Journal of Environmental & Earth Sciences in 2025
2026-02-06
Enhancing Circular Bioeconomy through Aerobic Granular Sludge: Experimental Insights into Nutrient Recovery from Kitchen Waste Leachate
Authors
-
Xiaosu Wu
School of Water Conservancy and Civil Engineering, Beijing Vocational College of Agriculture, Beijing 102442, China
DOI:
https://doi.org/10.30564/jees.v8i8.13585Abstract
Kitchen waste leachate is a variable, nutrient-rich liquid stream generated during the collection, storage, and processing of food waste. While it significantly increases the organic load, ammonium, phosphate, suspended solids, oils, and fermentation products are very troublesome in the treatment process; it also provides for the recovery of carbon, nitrogen, and phosphorus. This review critically analyzes the use of aerobic granular sludge (AGS) as a biological platform to improve circular bioeconomy strategies for recovering nutrients from kitchen waste leachate. The review combines leachate characteristics, granulation mechanisms in AGS, microbial nutrient pathways, experimental evidence, and integration pathways with downstream technologies for leachate recovery. The difference between pollutant removal and resource recovery is discussed, as is the fact that conventional nitrogen and phosphorus removal may not yield reusable products. The advantages of AGS treatment include compact dimensions, superior settleability, high biomass retention, and the simultaneous occurrence of carbon degradation and nitrification, anoxic and anaerobic microenvironments, and phosphorus accumulation. But high organic loading, ammonia inhibition, fats, salinity, influent inconsistency, and granule instability remain significant challenges. For recovery-oriented AGS systems, it is therefore beneficial to combine pretreatment, fermentation, struvite precipitation, ammonium recovery, membrane separation, or biomass valorization. Nutrient mass balances, product safety, pilot-scale validation, assessment of greenhouse gas(es) (GHG), and techno-economic analysis should be given greater importance in future research. In general, AGS is a potential bridge between biological treatment and nutrient circularity in sustainable food waste management systems, and between decentralized urban resource recovery and future cities.
Keywords:
Aerobic Granular Sludge; Kitchen Waste Leachate; Nutrient Recovery; Circular Bioeconomy; Struvite PrecipitationReferences
[1] Kehrein, P., van Loosdrecht, M., Osseweijer, P., et al., 2020. Exploring resource recovery potentials for the aerobic granular sludge process by mass and energy balances—Energy, biopolymer and phosphorous recovery from municipal wastewater. Environmental Science: Water Research & Technology. 6(8), 2164–2179. DOI: https://doi.org/10.1039/D0EW00310G
[2] Yadav, B., Atmakuri, A., Chavan, S., et al., 2021. Role of bioeconomy in circular economy. In: Pandey, A., Tyagi, R.D., Varjani, S. (Eds.). Biomass, Biofuels, Biochemicals: Circular Bioeconomy—Current Developments and Future Outlook. Elsevier: Amsterdam, The Netherlands. pp. 163–195. DOI: https://doi.org/10.1016/B978-0-12-821878-5.00022-2
[3] Paul, T., Yee, J.-J., Park, S.H., 2025. Biochar-assisted aerobic granulation in enhanced biological treatment of landfill leachate with municipal wastewater for sustainable resource recovery: A biorefinery approach. Journal of Environmental Chemical Engineering. 13(2), 115330. DOI: https://doi.org/10.1016/j.jece.2025.115330
[4] Guzmán-Fierro, V., Quiroz, M., Moscoso, K., et al., 2026. Aerobic granular sludge as a regenerative system for nutrient removal and metal recovery from landfill leachate. RSC Advances. 16(2), 1121–1133. DOI: https://doi.org/10.1039/D5RA05817A
[5] Mehta, C.M., Khunjar, W.O., Nguyen, V., et al., 2015. Technologies to recover nutrients from waste streams: A critical review. Critical Reviews in Environmental Science and Technology. 45(4), 385–427. DOI: https://doi.org/10.1080/10643389.2013.866621
[6] Cydzik-Kwiatkowska, A., 2021. Biopolymers in aerobic granular sludge—Their role in wastewater treatment and possibilities of re-use in line with circular economy. Energies. 14(21), 7219. DOI: https://doi.org/10.3390/en14217219
[7] Hamza, R., Rabii, A., Ezzahraoui, F.-Z., et al., 2022. A review of the state of development of aerobic granular sludge technology over the last 20 years: Full-scale applications and resource recovery. Case Studies in Chemical and Environmental Engineering. 5, 100173. DOI: https://doi.org/10.1016/j.cscee.2021.100173
[8] Sijan, A.H., Zhang, B., 2025. Accelerating the formation of aerobic granular sludge (AGS): Advances, challenges, and future perspectives. Water-Energy Nexus. 9, 75–84. DOI: https://doi.org/10.1016/j.wen.2025.08.004
[9] Vydehi, P., Ravindran, G., Shyamala, G., et al., 2025. Aerobic granular sludge-based wastewater treatment: Current trends, formation, applications, granulation, efficiency, and bottlenecks. Journal of Water Process Engineering. 70, 107075. DOI: https://doi.org/10.1016/j.jwpe.2025.107075
[10] Smoot, L., 2021. A Molecular-Level Interrogation of Ammonia Oxidizing Bioreactors: Comparing and Contrasting Nitritation and Nitrification [Master’s Thesis]. University of Idaho: Moscow, ID, USA.
[11] Qu, Z., Zhang, S., Ren, Y., et al., 2026. Resource recovery from aerobic granular sludge: Potential, methodologies and state of the art. Water. 18(5), 540. DOI: https://doi.org/10.3390/w18050540
[12] Ferreira, T.J.T., 2023. Study of emerging aerobic biotechnologies for sewage treatment and resource recovery [Master’s Thesis]. Federal University of Ceará: Fortaleza, Brazil.
[13] Dababat, S., Enaime, G., Wichern, M., et al., 2023. Aerobic granular sludge: Perspectives for excess sludge management and resource recovery. Chemie Ingenieur Technik. 95(12), 1881–1896. DOI: https://doi.org/10.1002/cite.202300093
[14] Chen, X., Wang, X., Wang, Q., et al., 2024. Energy and resource recovery from a future aerobic granular sludge wastewater treatment plant and benefit analysis. Chemical Engineering Journal. 487, 150558. DOI: https://doi.org/10.1016/j.cej.2024.150558
[15] Pagliaccia, B., Campo, R., Carretti, E., et al., 2024. Towards resource recovery-oriented solutions in agriculture exploiting structural extracellular polymeric substances (sEPS) extracted from aerobic granular sludge (AGS). Chemical Engineering Journal. 485, 149819. DOI: https://doi.org/10.1016/j.cej.2024.149819
[16] Al-Gheethi, A., Noman, E.A., Alsahari, M., et al., 2024. Potential of complex microbial community in aerobic granular sludge as a bio-startup approach for next-generation wastewater treatment. Applied Water Science. 14(10), 215. DOI: https://doi.org/10.1007/s13201-024-02268-2
[17] Shameem, K.S., Sabumon, P.C., 2023. A review on the stability, sustainability, storage and rejuvenation of aerobic granular sludge for wastewater treatment. Water. 15(5), 950. DOI: https://doi.org/10.3390/w15050950
[18] Wang, H., Xu, J., Sheng, L., 2019. Study on the comprehensive utilization of city kitchen waste as a resource in China. Energy. 173, 263–277. DOI: https://doi.org/10.1016/j.energy.2019.02.081
[19] Yuan, Q., Huang, Y., Chi, J., et al., 2024. Effective treatment of leachate concentrate from waste incineration plant by combination of coagulation and direct contact evaporation. Chemosphere. 349, 140880. DOI: https://doi.org/10.1016/j.chemosphere.2023.140880
[20] Gurjar, R., Behera, M., 2021. Effect of operating parameters on leachate quantity and quality generated during hydrolysis of kitchen waste. In: Kalamdhad, A.S. (Ed.). Integrated Approaches towards Solid Waste Management. Springer: Cham, Switzerland. pp. 255–264. DOI: https://doi.org/10.1007/978-3-030-70463-6_24
[21] Yan, Y., Liang, H., Wang, Z., et al., 2024. Attaining superior nitrogen removal from integrated mature landfill leachate and kitchen waste digestion liquid via a two-stage partial nitrification/anammox (PN/A) process. Chemical Engineering Journal. 480, 148352. DOI: https://doi.org/10.1016/j.cej.2023.148352
[22] Chen, Z., Zhang, S., Li, Y., et al., 2023. Investigating nitrous oxide emissions and mechanisms in kitchen waste composting with leachate reuse. Chemical Engineering Journal. 476, 146813. DOI: https://doi.org/10.1016/j.cej.2023.146813
[23] Ilmasari, D., Nishimura, F., 2025. Algal-bacterial aerobic granular sludge: Applications and future prospects. Journal of Water and Environment Technology. 23(2), 57–70. DOI: https://doi.org/10.2965/jwet.24-080
[24] Zhang, P., Chai, J., Cao, J., et al., 2023. Landfill leachate generation mechanism study: A review. International Journal of Environmental Science and Technology. 20(8), 9271–9290. DOI: https://doi.org/10.1007/s13762-022-04723-6
[25] Abdel-Shafy, H.I., Ibrahim, A.M., Al-Sulaiman, A.M., et al., 2024. Landfill leachate: Sources, nature, organic composition, and treatment: An environmental overview. Ain Shams Engineering Journal. 15(1), 102293. DOI: https://doi.org/10.1016/j.asej.2023.102293
[26] Sharma, V., Nagpal, G., Naveen, B.P., et al., 2026. An updated review on landfill leachate treatment methods. Discover Chemistry. 3(1), 34. DOI: https://doi.org/10.1007/s44371-026-00473-3
[27] Li, W., Liu, H., Deng, L., et al., 2024. Recent advances in treatment refinement of kitchen digested wastewater: Feasibility, prospects, and technicalities. Water Cycle. 5, 20–30. DOI: https://doi.org/10.1016/j.watcyc.2023.12.001
[28] Remmas, N., Manfe, N., Zerva, I., et al., 2023. A critical review on the microbial ecology of landfill leachate treatment systems. Sustainability. 15(2), 949. DOI: https://doi.org/10.3390/su15020949
[29] Babcock-Jackson, L., Konovalova, T., Krogman, J.P., et al., 2023. Sustainable fertilizers: Publication landscape on wastes as nutrient sources, wastewater treatment processes for nutrient recovery, biorefineries, and green ammonia synthesis. Journal of Agricultural and Food Chemistry. 71(22), 8265–8296.
[30] Ahmed, S.M., Rind, S., Rani, K., 2023. Systematic review: External carbon source for biological denitrification for wastewater. Biotechnology and Bioengineering. 120(3), 642–658. DOI: https://doi.org/10.1002/bit.28293
[31] Shen, N., Zhou, Y., 2016. Enhanced biological phosphorus removal with different carbon sources. Applied Microbiology and Biotechnology. 100(11), 4735–4745. DOI: https://doi.org/10.1007/s00253-016-7518-4
[32] Jun, Z., Fan, Z., Xiaofeng, L., et al., 2025. Insight of biological transformation process in the anaerobic codigestion of kitchen waste with landfill site closure leachate. Scientific Reports. 15(1), 22930. DOI: https://doi.org/10.1038/s41598-025-06866-1
[33] Mei, Z., Wang, J., Luo, J., et al., 2025. Unraveling the mechanism of dissolved organic matter in enhancing nitrogen removal from leachate wastewater treatment via aerobic granular sludge process. Water Research. 287, 124407. DOI: https://doi.org/10.1016/j.watres.2025.124407
[34] Ma, J., Sun, H., Ji, Y., et al., 2025. Niche differentiation drives microbial community assembly in an anaerobic/oxic/anoxic-aerobic granular sludge (AOA-AGS) system: Insights into anammox self-enrichment. Water Research. 288, 124615. DOI: https://doi.org/10.1016/j.watres.2025.124615
[35] da Silva, V.E.P.S.G., de Sousa Rollemberg, S.L., dos Santos, A.B., 2023. Step-feeding in aerobic/anoxic cycles enhanced the performance of aerobic granular sludge (AGS) systems treating effluents with low C:N ratios. Process Safety and Environmental Protection. 171, 1031–1042. DOI: https://doi.org/10.1016/j.psep.2022.10.004
[36] Wang, J., Li, Z., Wang, Q., et al., 2023. Use of photo-driven algal-bacterial aerobic granular sludge system to close carbon cycle in biological nutrients removal and sludge anaerobic digestion units in wastewater treatment plants. Chemical Engineering Journal. 475, 145999. DOI: https://doi.org/10.1016/j.cej.2023.145999
[37] Liu, L., Wang, C., Peng, Y., et al., 2025. Deciphering spatial microbial distribution in aerobic granules: Linking granulation dynamics to nitrogen metabolism in the continuous flow self-circulating reactor. Chemical Engineering Journal. 514, 163111. DOI: https://doi.org/10.1016/j.cej.2025.163111
[38] Rosas-Echeverría, K., Fall, C., Gutiérrez-Segura, E., et al., 2023. Mechanisms of persistence and impact of ordinary heterotrophic organisms in aerobic granular sludge. Bioresource Technology. 384, 129346. DOI: https://doi.org/10.1016/j.biortech.2023.129346
[39] Xiao, H., Wang, K., Wang, Y., et al., 2024. Inhibition of denitrification and enhancement of microbial interactions in the AGS system by high concentrations of quinoline. Journal of Environmental Management. 370, 122837. DOI: https://doi.org/10.1016/j.jenvman.2024.122837
[40] Ni, M., Pan, Y., Zhang, X., et al., 2021. Effects of P/C ratios on the growth, phosphorus removal and phosphorus recovery of a novel strain of highly efficient PAO. Process Biochemistry. 111, 109–117. DOI: https://doi.org/10.1016/j.procbio.2021.08.010
[41] Su, L., Li, Y., Chao, L., et al., 2023. Enhanced simultaneous nitrogen and phosphorus removal performance of the AGS-SBR reactor based on the effects of the C/N ratio and microbial community change. Sustainability. 15(9), 7691. DOI: https://doi.org/10.3390/su15097691
[42] Min, K.J., Lee, E., Lee, A.H., et al., 2024. Effect of settling time and organic loading rates on aerobic granulation processes treating high strength wastewater. Heliyon. 10(16), e36018. DOI: https://doi.org/10.1016/j.heliyon.2024.e36018
[43] Toja Ortega, S., van den Berg, L., Pronk, M., et al., 2022. Hydrolysis capacity of different sized granules in a full-scale aerobic granular sludge (AGS) reactor. Water Research X. 16, 100151. DOI: https://doi.org/10.1016/j.wroa.2022.100151
[44] Setianingsih, N.I., Hadiyanto, Budihardjo, M.A., et al., 2024. Effective sludge activation in a sequencing batch reactor (SBR) towards aerobic granular sludge (AGS) technology. Desalination and Water Treatment. 320, 100774. DOI: https://doi.org/10.1016/j.dwt.2024.100774
[45] Sarvajith, M., Nandini, D., Nancharaiah, Y., 2024. Comparative evaluation of activated sludge and aerobic granular sludge for biological treatment of real domestic wastewater with oxytetracycline dosing. Journal of Environmental Chemical Engineering. 12(2), 112482. DOI: https://doi.org/10.1016/j.jece.2024.112482
[46] Anjum, M., Anees, M., Qadeer, S., et al., 2023. A recent progress in the leachate pretreatment methods coupled with anaerobic digestion for enhanced biogas production: Feasibility, trends, and techno-economic evaluation. International Journal of Molecular Sciences. 24(1), 763. DOI: https://doi.org/10.3390/ijms24010763
[47] Zhang, Y.-X., Cai, X., Zhang, X.-G., et al., 2024. Periodic injection of liquefied kitchen and food waste in municipal solid waste: Effects on leachate and gas generation. Waste Management. 176, 1–10. DOI: https://doi.org/10.1016/j.wasman.2024.01.020
[48] da Silva, V.E.P.S.G., 2023. Aerobic granular sludge system optimization strategies for landfill leachate treatment and co-treatment with domestic sewage [Master’s Thesis]. Federal University of Ceará: Fortaleza, Brazil.
[49] Berenji Rahimzadeh, N., 2024. Impact of the co-treatment of food waste and municipal wastewater on the performance of an aerobic granular sludge system [Master’s Thesis]. İstanbul Technical University: Istanbul, Türkiye.
[50] Chen, H., Zhou, W., Xu, Z., et al., 2021. Nitrogen and phosphorus removal by GAOs and PAOs using nitrate and limited oxygen as electron acceptors simultaneously and the impact of external carbon source in the anoxic phase. Journal of Environmental Chemical Engineering. 9(6), 106520. DOI: https://doi.org/10.1016/j.jece.2021.106520
[51] Chen, J., Wang, J., Wang, X., et al., 2022. Strengthening anoxic glycogen consumption in SNEDPR-CW as a strategy to control PAO-GAO competition under carbon limited condition. Chemosphere. 288, 132617. DOI: https://doi.org/10.1016/j.chemosphere.2021.132617
[52] Chen, H.-B., Wang, D.-B., Li, X.-M., et al., 2015. Enhancement of post-anoxic denitrification for biological nutrient removal: Effect of different carbon sources. Environmental Science and Pollution Research. 22(8), 5887–5894. DOI: https://doi.org/10.1007/s11356-014-3755-1
[53] Gong, B., Duan, K., Chen, S., et al., 2023. Enhanced nutrients removal and microbial mechanisms in a pilot-scale anaerobic-oxic-anoxic (A/O/A) system: Synergistic roles of denitrifying polyphosphate accumulating organisms and endogenous denitrifiers. Process Safety and Environmental Protection. 179, 47–56. DOI: https://doi.org/10.1016/j.psep.2023.08.085
[54] Morales-Polo, C., Cledera-Castro, M.D.M., Moratilla Soria, B.Y., 2018. Reviewing the anaerobic digestion of food waste: From waste generation and anaerobic process to its perspectives. Applied Sciences. 8(10), 1804. DOI: https://doi.org/10.3390/app8101804
[55] Siciliano, A., Limonti, C., Curcio, G.M., et al., 2020. Advances in struvite precipitation technologies for nutrients removal and recovery from aqueous waste and wastewater. Sustainability. 12(18), 7538. DOI: https://doi.org/10.3390/su12187538
[56] Podder, A., Reinhart, D., Goel, R., 2020. Integrated leachate management approach incorporating nutrient recovery and removal. Waste Management. 102, 420–431. DOI: https://doi.org/10.1016/j.wasman.2019.10.048
[57] da Silva, V.E.P.S.G., Fiorani Ezequiel, T., Iorhemen, O., et al., 2026. Adaptation and application of methodologies for quantification of xanthan and curdlan in conventional AGS systems and algal-bacterial association. Biomass and Bioenergy. 205, 108558. DOI: https://doi.org/10.1016/j.biombioe.2025.108558
[58] da Silva, V.E.P.S.G., de S. Rollemberg, S.L., da S. e Santos, S.G., et al., 2022. Landfill leachate biological treatment: Perspective for the aerobic granular sludge technology. Environmental Science and Pollution Research. 29(30), 45150–45170. DOI: https://doi.org/10.1007/s11356-022-20451-3
[59] Kazimierowicz, J., Dębowski, M., 2022. Aerobic granular sludge as a substrate in anaerobic digestion—Current status and perspectives. Sustainability. 14(17), 10904. DOI: https://doi.org/10.3390/su141710904
[60] Wang, J., Qiao, Z., 2024. A comprehensive review of landfill leachate treatment technologies. Frontiers in Environmental Science. 12, 1439128. DOI: https://doi.org/10.3389/fenvs.2024.1439128
[61] Gusiatin, M.Z., Kulikowska, D., Bernat, K., 2024. Municipal sewage sludge as a resource in the circular economy. Energies. 17(11), 2474. DOI: https://doi.org/10.3390/en17112474
[62] Karthikeyan, O.P., 2008. Solubilization of ammoniacal nitrogen in landfills under tropical environments—Effects on waste stabilization and struvite recovery [PhD Thesis]. Anna University: Chennai, India.
[63] Mady, E., Oleszkiewicz, J., Yuan, Q., 2026. Phosphorus-rich liquid extraction strategies to enhance phosphorus removal in aerobic granular sludge treating municipal wastewater. Bioresource Technology Reports. 34, 102852. DOI: https://doi.org/10.1016/j.biteb.2026.102852
[64] Pagliano, G., Ventorino, V., Panico, A., et al., 2017. Integrated systems for biopolymers and bioenergy production from organic waste and by-products: A review of microbial processes. Biotechnology for Biofuels. 10(1), 113. DOI: https://doi.org/10.1186/s13068-017-0802-4
[65] Dung, N.P., 2022. Nitrous oxide emissions during wastewater treatment process [Master’s Thesis]. Technische Universität Darmstadt: Darmstadt, Germany.
[66] Cavanaugh, S.K., 2021. Nitrous Oxide Emissions from Wastewater Treatment Processes and Process Parameters Affecting Emissions [Master’s Thesis]. University of Washington: Seattle, WA, USA .
[67] Sharrer, M., Rishel, K., Taylor, A., et al., 2010. The cost and effectiveness of solids thickening technologies for treating backwash and recovering nutrients from intensive aquaculture systems. Bioresource Technology. 101(17), 6630–6641. DOI: https://doi.org/10.1016/j.biortech.2010.03.101
[68] Yu, C., Wang, K., 2024. Continuous flow aerobic granular sludge: Recent developments and applications. Water Science & Technology. 89(5), 1155–1178. DOI: https://doi.org/10.2166/wst.2024.055
[69] Upadhyay, S.K., 2026. Composting: Safety and regulatory considerations in sustainable agriculture. In: Singh, R.K., Trindade, H., Sousa, J.R., et al. (Eds.). Composting of Farm Residues by Nature-Based Solutions: A Potential Key towards Sustainable Agricultural Practices. Springer: Cham, Switzerland. pp. 379–409. DOI: https://doi.org/10.1007/978-3-032-12255-1_15
[70] Kazimierowicz, J., Dębowski, M., Zieliński, M., 2022. Microbial granule technology—Prospects for wastewater treatment and energy production. Energies. 16(1), 75. DOI: https://doi.org/10.3390/en16010075
[71] Ahmed, M., Ahmad, S., Fayyaz-ul-Hassan, et al., 2019. Innovative processes and technologies for nutrient recovery from wastes: A comprehensive review. Sustainability. 11(18), 4938. DOI: https://doi.org/10.3390/su11184938
Downloads
How to Cite
Wu, X. (2026). Enhancing Circular Bioeconomy through Aerobic Granular Sludge: Experimental Insights into Nutrient Recovery from Kitchen Waste Leachate. Journal of Environmental & Earth Sciences, 8(8), 450–476. https://doi.org/10.30564/jees.v8i8.13585
Issue
Article Type
Review
License
Copyright © 2026 Xiaosu Wu
This is an open access article under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) License.
