Fouling Caused by EPS
Extra-cellular polymeric substances (EPS) are
products of active secretion, cell surface material
shedding, cell lysis and sorption from the environment
[23] and EPS has been identified as the main foulant
in MBR processes [24],[25]. The EPS matrix can be
characterized by its relative levels of polysaccharides,
proteins, and more rarely lipids and nucleic acids
[26],[27]. EPS is produced by most bacteria and
participates in the formation of microbial aggregates
whether the bacteria grow in suspended culture or
in biofilms [28],[29]. Consequently, EPS plays an
important role in the flocculation, settling and
dewatering of activated sludge [30].
A positive relationship between the higher the
suspended EPS concentration, the lower the filtration
ability was showed in various researches [31],[32].
On the contrary, some research showed that the higher
EPS caused a better filtration [33].
EPS can be classified as extracted EPS which
are artificially produced from the biological cell flocs
and the soluble EPS which are present in the activated
sludge supernatant and are not associated with the cell
(soluble microbial products) [34]. So far no standard
method for EPS extraction exists, which causes difficulty
in making a comparison between research groups.
Fouling Caused by EPSExtra-cellular polymeric substances (EPS) areproducts of active secretion, cell surface materialshedding, cell lysis and sorption from the environment[23] and EPS has been identified as the main foulantin MBR processes [24],[25]. The EPS matrix can becharacterized by its relative levels of polysaccharides,proteins, and more rarely lipids and nucleic acids[26],[27]. EPS is produced by most bacteria andparticipates in the formation of microbial aggregateswhether the bacteria grow in suspended culture orin biofilms [28],[29]. Consequently, EPS plays animportant role in the flocculation, settling anddewatering of activated sludge [30].A positive relationship between the higher thesuspended EPS concentration, the lower the filtrationability was showed in various researches [31],[32].On the contrary, some research showed that the higherEPS caused a better filtration [33].EPS can be classified as extracted EPS whichare artificially produced from the biological cell flocsand the soluble EPS which are present in the activatedsludge supernatant and are not associated with the cell(soluble microbial products) [34]. So far no standardmethod for EPS extraction exists, which causes difficultyin making a comparison between research groups.
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