Primary and A-sludge treatment by anaerobic membrane bioreactors in view of energy-positive wastewater treatment plants

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Mustafa Abdelrahman A., Furkan Aras M., Çiçekalan B., Fakioglu M., Cingoz S., Basa S., ...More

Bioresource Technology, vol.351, 2022 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 351
  • Publication Date: 2022
  • Doi Number: 10.1016/j.biortech.2022.126965
  • Journal Name: Bioresource Technology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Compendex, EMBASE, Environment Index, Food Science & Technology Abstracts, Geobase, INSPEC, MEDLINE, Pollution Abstracts, Veterinary Science Database, Civil Engineering Abstracts
  • Keywords: A-stage, Anaerobic membrane bioreactor, Sludge digestion, Energy recovery, Nutrient recovery
  • Istanbul Technical University Affiliated: Yes


Energy-rich sludge can be obtained from primary clarifiers preceding biological reactors. Alternatively, the incoming wastewater can be sent to a very-high-loaded activated sludge system, i.e., a so-called A-stage. However, the effects of applying an A-stage instead of a primary clarifier, on the subsequent sludge digestion for long-term operation is still unknown. In this study, biogas production and permeate quality, and filterability characteristics were investigated in a lab-scale anaerobic membrane bioreactor for primary sludge and A-stage sludge (A-sludge) treatment. A higher specific methane yield was obtained from digestion of A-sludge compared to primary sludge. Similarly, specific methanogenic activity was higher when the anaerobic membrane bioreactor was fed with A-sludge compared to primary sludge. Plant-wide mass balance analysis indicated that about 35% of the organic matter in wastewater was recovered as methane by including an A-stage, compared to about 20% with a primary clarifier.