Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
권호 표지
DOI QR코드

DOI QR Code

Effects of High-efficiency Digestion System and Microbial Diversity with Internal Recirculation

  • Sang Kyu Park (School of Environmental Science and Engineering, POSTECH) ;
  • Suk Soon Choi (Department of Biological and Environmental Engineering, Semyung University) ;
  • Jeong Hyub Ha (Department of Integrated Environmental Systems, Pyeongtaek University)
  • Received : 2024.10.12
  • Accepted : 2024.11.03
  • Published : 2024.12.10
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, a combined sludge digestion process consisting of a mesophilic anaerobic digester (MAD) and a thermophilic aerobic digester (TAD) was developed. The effects of recirculation on the combined sludge digestion process were investigated. The volatile suspended solids (VSS) removal rate increased from 76% to 97% when internal recirculation was applied and remained stable until the end of the experiment. In contrast, the concentration of total suspended solids (TSS) increased slightly because of the accumulation of inert materials in the reactors. The methane production of the combined process showed the highest level of 260 mL/L/day in phase two and decreased to 170 mL/L/day as the strength of the pre-treatment decreased. At phase five, the influent and recirculated sludge were supplied without pre-treatment. During this phase, methane production rate decreased from 170 mL/L/day to 40 mL/L/day, and rapid accumulation of TSS and VSS occurred. However, the thermophilic aerobic digester was stable, and VSS accumulation was not observed. This indicates that the sludge removal ability of the combined process can be stably maintained without sludge pretreatment. Collectively, results of this experiment indicate that pre-treatment of influent sludge and internal recirculation of treated sludge from the TAD to the combined process are necessary for effective energy production and improved sludge removal in the combined process.

Keywords

References

  1. MOE, 2009. Sewage Sludge Management and Planning. Seoul, Korea.
  2. G. B. Kim, R. D. A. Cayetano, J. Park, Y. Jo, S. Park, M. E. Ersahin, and S. H. Kim, Effects of solids concentration and thermal pretreatment on continuous digestion of undigested dewatered sludge, Renew. Energy, 231, 120894 (2024). https://doi.org/10.1016/j.renene.2024.120894
  3. J. Park, R. D. A. Cayetano, Y. Kwon, G. B. Kim, Y. Jo, and S. H. Kim, Improved sludge anaerobic digestion capacity by dynamic membrane and alkaline-thermal pretreatment: Long-term continuous operation and techno-economic analysis, Chem. Eng. J., 474, 145735 (2023).
  4. G. B. Kim, R. D. A. Cayetano, J. S. Park, Y. R. Jo, S. Y. Jeong, M. Y. Lee, A. Pandey, and S. H. Kim, Impact of thermal pretreatment on anaerobic digestion of dewatered sludge from municipal and industrial wastewaters and its economic feasibility, Energy, 254, 124345 (2022). https://doi.org/10.1016/j.energy.2022.124345
  5. M. A. H. Jannat, S. H. Park, C. Chairattanawat, A. Yulisa, and S. Hwang, Effect of different microbial seeds on batch anaerobic digestion of fish waste, Bioresour. Technol., 349, 126834 (2022). https://doi.org/10.1016/j.biortech.2022.126834
  6. S. Kim, E. Kim, and S. Hwang, Methanogenic diversity changes in full-scale anaerobic digesters by co-digestion of food waste and sewage sludge, J. Mater. Cycles Waste Manag., 24, 2669–2676 (2022). https://doi.org/10.1007/s10163-022-01482-x
  7. H. G. Kelly and D. S. Mavinic, Autothermal thermophilic aerobic digestion research application and operational experience, WEFTEC 2003 Workshop W104 Thermophilic Digestion. November 11, Los Angeles, U.S.A (2003).
  8. C. Dumas, S. Perez, E. Paul, and X. Lefebvre, Combined thermophilic aerobic process and conventional anaerobic digestion: Effect on sludge biodegradation and methane production, Bioresour. Technol., 101, 2629-2636 (2010). https://doi.org/10.1016/j.biortech.2009.10.065
  9. J. T. Novak, S. Banjade, and S. N. Murthy, Combined anaerobic and aerobic digestion for increased solids reduction and nitrogen removal, Water Res., 45, 618-624 (2011). https://doi.org/10.1016/j.watres.2010.08.014
  10. S. K. Park, H. M. Jang, J. H. Ha, and J. M. Park, Sequencial sludge digestion after diverse pre-treatment conditions: sludge removal, methane production and microbial community changes, Bioresour. Technol., 162, 331-340 (2014). https://doi.org/10.1016/j.biortech.2014.03.152
  11. APHA, Standard Method for the Examination of Water and Wastewater, 21st ed., Water Environment Federation, Washington, DC, U.S.A (2005).
  12. S. Liu, F. Song, N. Zhu, H. Yuan, and J. Cheng, Chemical and microbial changes during autothermal thermophilic aerobic digestion (ATAD) of sewage sludge, Bioresour. Technol., 101, 9438-9444 (2010). https://doi.org/10.1016/j.biortech.2010.07.064
  13. M. D. Kim, M. K. Song, M. H. Jo, S. G. Shin, J. H. Khim, and S. H. Hwang, Growth condition and bacterial community for maximum hydrolysis of suspended organic materials I anaerobic digestion of food waste-recycling wastewater, Appl. Microbiol. Biotechnol., 85, 1611-1618 (2010). https://doi.org/10.1007/s00253-009-2316-x
  14. X. S. Li, H. Z. Ma, Q. H. Wang, S. Matsumoto, T. Maeda, and H. I. Ogawa, Isolation, identification of sludge-lysing strain and its utilization in thermophilic aerobic digestion for waste activated sludge, Bioresour. Technol., 100, 2475-2481 (2009). https://doi.org/10.1016/j.biortech.2008.12.019
  15. D. Sousa, J. Alves, M. M. Alves, H. Smidt, and A. J. Alfons, Effect of sulfate on methanogenic communities that degrade unsaturated and saturated long-chain fatty acids (LCFA), Environ. Microbiol., 11, 68-80 (2009). https://doi.org/10.1111/j.1462-2920.2008.01740.x
  16. T. Koo, A. Yulisa, and S. Hwang, Microbial community structure in full scale anaerobic mono-and co-digesters treating food waste and animal waste, Bioresour. Technol., 282, 439-446 (2019) https://doi.org/10.1016/j.biortech.2019.03.050