Anaerobic Digestion, Important Aspects Regarding Digester Design and Sludge Mixing Systems

  • Bogdanka Radetic
Living reference work entry


Anaerobic sludge digestion is a natural process in which bacteria decompose organic material, whereby the sludge is stabilized and at the same time, biogas is produced. Owing to sludge stabilization, the sludge volume is reduced and with it, the carbon footprint of the used water treatment plant and transportation costs. This process is highly complex and sensitive and takes place in anaerobic digesters. Anaerobic digesters have been used for decades at municipal used water facilities and are designed to maximize the degradation of organic matter and optimize the growth of the bacteria that generate methane. There are many differing digester shapes and mixing possibilities, but irrespective of the design employed, several operating conditions must exist in order that optimum organic material degradation is attained. For this reason, anaerobic processes, digester design, and digester mixing are closely connected and an understanding of these relationships is very important when choosing and setting up a system.



Dry solids


Expanded polystyrene


Used water treatment plant


Volatile solids


  1. Appels L, Baeyens J, Degrève J, Dewil R (2008) Principles and potential of the anaerobic digestion of waste-activated sludge. Prog Energy Combust Sci 34(6):755–781CrossRefGoogle Scholar
  2. Brade CE, Noone GP (1981) Anaerobic sludge digestion – need it to be expensive? Making more of existing resources. Water Pollut Control 80:70–94Google Scholar
  3. EPA (2006) United States Environmental Protection Agency, Biosolids Technology Fact Sheet. Multistage anaerobic digestion, EPA 832-F-06-031, Office of Water, Washington, DC, September 2006Google Scholar
  4. Gerardi MH (2003) Wastewater microbiology series: the microbiology of anaerobic digesters. Wiley, New YorkCrossRefGoogle Scholar
  5. Merkblatt DWA-M 368 Biologische Stabilisierung von Klärschlamm (2014) Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e. V.Google Scholar
  6. Monnet F (2003) An Introduction to Anaerobic Digestion of Organic Wastes. A Report by Remade ScotlandGoogle Scholar
  7. Paul EL, Atiemo-Obeng VA, Kresta SM (2004) Handbook of industrial mixing: science and practice. Wiley, HobokenGoogle Scholar
  8. Qasim SR (1999) Wastewater treatment plants: planning. Design and operation, 2nd edn. CRC Press, Boca RatonGoogle Scholar
  9. Rajabu YR, Manyele SV (2015) Performance improvement for sisal waste anaerobic biodegradation by digester redesign and feed size reduction. Engineering 2015(7):553–566CrossRefGoogle Scholar
  10. Tiehm A, Nickel K, Zellhorn M, Neis U (2001) Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization. Water Res 35:2003–2009CrossRefGoogle Scholar
  11. Turovskiy IS, Mathai PK (2006) Wastewater sludge processing. Wiley, New YorkCrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  • Bogdanka Radetic
    • 1
    • 2
  1. 1.Faculty of TechnologyNovi Sad UniversityNovi SadSerbia
  2. 2.Civil Engineering and Water ManagementUniversity of Natural Resources and Life SciencesViennaAustria

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