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Zero-waste strategy of small wastewater treatment plants with integrated thermal treatment of generated solid wastes

Author

Listed:
  • Urbancl, D.
  • Hochenauer, C.
  • Zachl, A.
  • Fekonja, N.
  • Petrovic, A.
  • Goricanec, D.
  • Simonic, M.

Abstract

The aim of the study was to analyse two small wastewater treatment plants (SWTPs) and compare their treatment performance with the aim of developing a zero-waste strategy. The analyses showed that the second wastewater treatment plant had a problem with an increased phosphorus concentration in the wastewater as well as fluctuations in nitrogen removal. One of the key aspects was the recovery of phosphorus in the form of struvite precipitated on zeolite, which can be used as a fertiliser due to its significant nutrient content. The main benefit of the same SWTP is the separate collection of cellulosic material (labelled as sample RS), which has the potential for reuse as biochar, while from the first SWTP the sludge sample (labelled as sample SS) was taken and torrefied for comparison with RS. Both samples were torrefied at 250 °C and 350 °C in nitrogen and carbon dioxide atmospheres. The RS products obtained in CO2 atmosphere at 350 °C showed the best biochar properties, as they had a higher heating value (HHV) and a higher C content. Elemental analysis showed that the carbon content in RS and SS increased from 43 to 65 % and from 35 to 39 %, respectively. Measurement of the HHV of the torrefied RS product showed an increase from 17 to 26 MJ/kg, while for SS it increased from 15 to 17 MJ/kg. The comprehensive combustion index and the EMCI index show higher values for the RS samples torrefied at 350 °C. The H/C and O/C ratios are favourable for these samples, as the high quality of torrefied biomass is associated with the highest prices on the market. According to the TGA and FTIR analysis, the type of torrefaction atmosphere, in contrast to the torrefaction temperature, has little influence on the subsequent use of the torrefied samples in combustion. The results show that the integration of torrefaction for biochar production with phosphorus recovery by struvite precipitation is an efficient solution for waste management in small wastewater treatment plants.

Suggested Citation

  • Urbancl, D. & Hochenauer, C. & Zachl, A. & Fekonja, N. & Petrovic, A. & Goricanec, D. & Simonic, M., 2025. "Zero-waste strategy of small wastewater treatment plants with integrated thermal treatment of generated solid wastes," Energy, Elsevier, vol. 337(C).
    • Handle: RePEc:eee:energy:v:337:y:2025:i:c:s0360544225043828
    DOI: 10.1016/j.energy.2025.138740
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    References listed on IDEAS

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    1. Faisal, M. & Muttaqi, Kashem M. & Sutanto, Danny & Al-Shetwi, Ali Q. & Ker, Pin Jern & Hannan, M.A., 2023. "Control technologies of wastewater treatment plants: The state-of-the-art, current challenges, and future directions," Renewable and Sustainable Energy Reviews, Elsevier, vol. 181(C).
    2. Gan, Yong Yang & Ong, Hwai Chyuan & Ling, Tau Chuan & Chen, Wei-Hsin & Chong, Cheng Tung, 2019. "Torrefaction of de-oiled Jatropha seed kernel biomass for solid fuel production," Energy, Elsevier, vol. 170(C), pages 367-374.
    3. Arkadiusz Dyjakon & Tomasz Noszczyk & Łukasz Sobol & Dominika Misiakiewicz, 2021. "Influence of Torrefaction Temperature and Climatic Chamber Operation Time on Hydrophobic Properties of Agri-Food Biomass Investigated Using the EMC Method," Energies, MDPI, vol. 14(17), pages 1-19, August.
    4. Maja Ivanovski & Darko Goričanec & Danijela Urbancl, 2023. "The Evaluation of Torrefaction Efficiency for Lignocellulosic Materials Combined with Mixed Solid Wastes," Energies, MDPI, vol. 16(9), pages 1-15, April.
    5. Ma, Zhangke & Cheng, Leming & Wang, Qinhui & Li, Liyao & Luo, Guanwen & Zhang, Weiguo, 2022. "Co-combustion characteristics and CO2 emissions of low-calorific multi-fuels by TG-FTIR analysis," Energy, Elsevier, vol. 252(C).
    6. Ivanovski, Maja & Goricanec, Darko & Krope, Jurij & Urbancl, Danijela, 2022. "Torrefaction pretreatment of lignocellulosic biomass for sustainable solid biofuel production," Energy, Elsevier, vol. 240(C).
    7. Zhao, Ruixin & Liu, Shanjian & Li, Zhihe & Liu, Yinjiao & Li, Ning & Xu, Pan, 2024. "Exergy, exergoeconomic and carbon emission analysis of a novel biomass pyrolysis system with self-heating and torrefaction," Energy, Elsevier, vol. 313(C).
    8. Niu, Yanqing & Lv, Yuan & Lei, Yu & Liu, Siqi & Liang, Yang & Wang, Denghui & Hui, Shi'en, 2019. "Biomass torrefaction: properties, applications, challenges, and economy," Renewable and Sustainable Energy Reviews, Elsevier, vol. 115(C).
    9. Zachl, A. & Soria-Verdugo, A. & Buchmayr, M. & Gruber, J. & Anca-Couce, A. & Scharler, R. & Hochenauer, C., 2022. "Stratified downdraft gasification of wood chips with a significant bark content," Energy, Elsevier, vol. 261(PB).
    10. Chen, Wei-Hsin & Lu, Ke-Miao & Tsai, Chi-Ming, 2012. "An experimental analysis on property and structure variations of agricultural wastes undergoing torrefaction," Applied Energy, Elsevier, vol. 100(C), pages 318-325.
    11. Šantl, Neža & Stergar, Janja & Bozicko, Matevz & Goričanec, Darko & Urbancl, Danijela & Petrovič, Aleksandra, 2024. "The utilisation of thermally treated poultry farm waste for energy recovery and soil application," Renewable Energy, Elsevier, vol. 221(C).
    12. Mong, Guo Ren & Chong, William Woei Fong & Nor, Siti Aminah Mohd & Ng, Jo-Han & Chong, Cheng Tung & Idris, Rubia & Too, Jingwei & Chiong, Meng Choung & Abas, Mohd Azman, 2021. "Pyrolysis of waste activated sludge from food manufacturing industry: Thermal degradation, kinetics and thermodynamics analysis," Energy, Elsevier, vol. 235(C).
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