Biological control of biofilms on membranes by metazoans

Journal article (2016)

Authors

Theresa Klein Eawag - Swiss Federal Institute of Aquatic Science and Technology, Institute for Corrosion Protection (IKS) Dresden
David Zihlmann ETH Zürich, Eawag - Swiss Federal Institute of Aquatic Science and Technology
Nicolas Derlon ETH Zürich, Eawag - Swiss Federal Institute of Aquatic Science and Technology
Carl Isaacson Eawag - Swiss Federal Institute of Aquatic Science and Technology, Bemidji State University
Ilona Szivak Eawag - Swiss Federal Institute of Aquatic Science and Technology
D.G. Weissbrodt Eawag - Swiss Federal Institute of Aquatic Science and Technology, BT/Environmental Biotechnology - AS , ETH Zürich
Wouter Pronk Eawag - Swiss Federal Institute of Aquatic Science and Technology
Research Group
BT/Environmental Biotechnology (AS) (TU Delft)
Biofouling Basal layer Biological control Flux increase Gravity driven membrane Nematodes Oligochaetes
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Published Date

2016

Language

English

Reuse Rights

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Faculty

Applied Sciences

Department

BT/Biotechnologie

Research Group

BT/Environmental Biotechnology

Abstract

Traditionally, chemical and physical methods have been used to control biofouling on membranes by inactivating and removing the biofouling layer. Alternatively, the permeability can be increased using biological methods while accepting the presence of the biofouling layer. We have investigated two different types of metazoans for this purpose, the oligochaete Aelosoma hemprichi and the nematode Plectus aquatilis. The addition of these grazing metazoans in biofilm-controlled membrane systems resulted in a flux increase of 50% in presence of the oligochaetes (Aelosoma hemprichi), and a flux increase of 119-164% in presence of the nematodes (Plectus aquatilis) in comparison to the control system operated without metazoans. The change in flux resulted from (1) a change in the biofilm structure, from a homogeneous, cake-like biofilm to a more heterogeneous, porous structure and (2) a significant reduction in the thickness of the basal layer. Pyrosequencing data showed that due to the addition of the predators, also the community composition of the biofilm in terms of protists and bacteria was strongly affected. The results have implications for a range of membrane processes, including ultrafiltration for potable water production, membrane bioreactors and reverse osmosis.