Problems associated with biofouling are common in facilities that handle seawater, despite the low biodegradability of natural organic matter (NOM) in seawater.

In this Spanish–French work, a fixed-film aerobic biofilter is proposed as an effective unit to prevent biofouling in such facilities.

A packed-bed biofilter with an empty bed contact time (EBCT) of 6–11 minutes was employed. The results demonstrate that dissolved organic carbon (DOC) is reduced by 6%, and the biochemical oxygen demand at 7 days (BOD7) is reduced by up to 15%.

Analysis using liquid chromatography coupled with organic carbon detection (LC-OCD) revealed that biofiltration abates the low molecular weight (LMW) neutrals and biopolymer fractions by 33% and 17%, respectively.

However, fractionation with an ultrafiltration (UF) membrane showed that the biofiltration process is able to degrade the more biodegradable compounds that have molecular weights greater than 1 kDa and compounds with molecular weights of less than 1 kDa.

After biofiltration, the biological activity measured in terms of adenosine triphosphate (ATP) removal was reduced by 60%.

Finally, a test to evaluate the biofilm formation capacity of a water sample revealed reductions of approximately 94% when comparing biofiltered and non-biofiltered seawater.

Therefore, a fixed-film aerobic biofiltration process could be a useful treatment for the removal of biodegradable organic matter from seawater, and to improve water quality in terms of less biofilm formation capacity.

Desalination, Volume 316, 1 May 2013, Pages 8–16.