Water Treatment of Biological Methanation

Benedikt Rahe

Research output: ThesisMaster's Thesis


As basis for a nutrient recovery in biological methanation, the rejection performance of a polyamide reverse osmosis membrane treating a multiple-salt solutions at 65°C is experimentally investigated. The samples are (a) composed of an abiotic salt solution and (b) of a biotic mixture of salt solution and archaea (Methanothermobacter thermautotrophicus). The rejection is calculated based on conductivity measurements. In diafiltration mode, the use of the membrane leads to 60-fold more time for the abiotic solution to reach 25% of the initial concentration, compared to a theoretical calculation without reverse osmosis. In normal operation mode, the membrane stabilizes at 90% rejection. The rejection performance of the membrane and the biotic solution is impeded by cell lysis and a resulting ion release. Quantitative analyses of the feed and permeate streams reveals an unequal retention of the different ion species. The group of better retained ions contains molybdenum, cobalt, magnesium, iron, nickel, and phosphorus; the group of lesser retained ions consists of sodium and potassium. An economic calculation shows that the membrane system can save 84% ± 12% of the cost of the ions used.
Translated title of the contributionWasseraufbereitung in der Biologischen Methanisierung
Original languageEnglish
Awarding Institution
  • Montanuniversität
  • Lehner, Markus, Supervisor (internal)
  • Pinder, Zachary, Supervisor (external), External person
Award date21 Oct 2022
Publication statusPublished - 2022

Bibliographical note

embargoed until 03-10-2027


  • water treatment
  • biological methanation
  • archaea
  • reverse osmosis
  • reverse osmosis at elevated temperatures
  • nutrient recovery
  • membrane purification

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