Characterization of the Regenerative Capacity of Membranes in the Presence of Fouling by Microalgae Using Detergents

TL;DR

This paper studies how different cleaning methods affect the regenerative capacity of membranes fouled by microalgae, finding that chemical and enzymatic methods are more effective than traditional approaches.

Contribution

The study introduces a novel comparison of mechanical, chemical, and biological cleaning methods for microalgae-fouled membranes.

Findings

Backwashing removes pore blockages but fails to eliminate surface biofilm.

Chemical cleaning with oxidative agents or anionic surfactants effectively removes biofilm.

Enzymatic cleaning improves performance by 61% over commercial agents and 42% over backwashing.

Abstract

The filtration of microalgae generates fouling through algal matter and exopolymer particles with consequences for the flow rate. Therefore, regeneration that is as complete and continuous as possible is necessary. For this purpose, a commercial membrane with a pore size of 0.8 µm is contaminated with the microalgae mixture Haematoccocus Pluvialis and Tetradesmus obliquus, and then regenerated with mechanical (backwashing), chemical (HCl, NaOH, NaClO, P3-Ultrasil) and biological (dishwashing and laundry detergents) cleaning methods. The filtration time of the individual experiments is compared with a new membrane, and the increase is determined. Backwashing cleans the pores, but the biofilm sticks to the membrane surface and blocks the pores shortly after a new cycle. It was shown that the biofilm can only be removed chemically through oxidative effects or anionic surfactants. Hydrolysis does not remove the biofilm, and it can actually make the blockage worse. Bigger cellular residues can only be removed with enzymes. This improves cleaning performance by 61% compared to commercial cleaning agents for membranes and 42% compared to backwashing.

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