Sewage fungus

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Sewage fungus Sphaerotilus natans

Wastewater fungus is a colloquial term for a community of diverse bacteria (Bacteria) that grows in polluted ( eutrophicated ) waters and forms long threads or fur-like coatings. In the water quality determination it serves as an indicator for the water quality class III – IV.

In sewage treatment plants, this thread-like growth form can lead to problems, since the sludge then no longer settles in the secondary clarifier of sewage treatment plants as desired , but instead expands, foam forms and rises.

Until the 1960s, “ Sphaerotilus , the so-called wastewater fungus”, was spoken of as the cause of these operational problems. It was not until 1975, after Eikelboom differentiated the various thread organisms in the activated sludge on the basis of morphological and color criteria, that it became apparent that around 30 different thread bacteria play a role in bulky sludge and floating sludge .

Examples are: Thiothrix sp., Beggiatoa sp., Type 021N and Type 0914, Microthrix parvicella , nocardioform actinomycetes , Type 0041/0675, Type 0092, Type 1851 and Nostocoida limicola Kunst et al. 2000. Sphaerotilus natans , Haliscomenobacter hydrossis , type 021N, type 1701 and type 1863.

As a rule, various factors cause the problem of bulking and floating sludge in sewage treatment plants, for example a one-sided wastewater composition, procedural boundary conditions such as the set sludge load, the type of aeration, the achievable oxygen content and the precipitant used . Therefore, several measures are usually necessary to solve the problem.

literature

  • Gerhard Höhnl: Nutritional and metabolic physiological studies on Sphaerotilus natans . In: Archives for Microbiology . tape 23 , no. 3 , 1955, pp. 207-250 , doi : 10.1007 / bf00407897 .
  • TG Schmitt, J. Hansen, Michael M. Richter, A. Stahl: Central collection system for advice on bulking and floating sludge problems in municipal sewage treatment plants - final report . Technical University of Kaiserslautern 2003 (previously online )

Individual evidence

  1. ↑ DH Eikelboom, HJJ van Buijson: Handbook for microscopic sludge examination . 3. Edition. Hirthammer, Munich 1992, ISBN 3-88721-013-1 .