Environmental Engineering Reference
In-Depth Information
Fig. 6.1 Basic steps in
biofilm formation. (Adapted
from Francolini et al. [79])
are formed by bridging cells and EPS in conjunction with non-cellular substances,
such as trapped inorganic particles, to form an environment.
Formation of biofilms has been associated with a broad range of problems and
costs billions of dollars to industry each year [2]. In water distribution systems,
biofilm formations are ubiquitous and controls of their growth have been great chal-
lenges. Reports frommany water utilities in the US have shown that biofilms survive
in water distribution systems, despite the continuing presence of disinfectants [3, 4].
They also harbor various types of microorganisms including pathogenic and oppor-
tunistic pathogens and threaten public health [5, 6]. In addition to water distribution
systems, biofilm formations cause metal corrosion, material deterioration, and foul-
ing of heat exchangers, membranes and ship hulls. Corrosion of metals caused by
sulfate reducing biofilm is a universal problem. In the medical industry, biofilm
formation on human lung, medical devices, and artificial organs also have been of
great concern [7, 8]. The various problems associated with biofilms are summarized
in Table 6.1.
Table 6.1 Problems associated with biofilm formation
Environment Problem location
Consequences
References
Industrial
Membrane filtration
units
Total flux loss, energy loss,
reduction of membrane life
[77]
Heat exchanger
Loss of heat exchange efficiency,
energy loss
[75, 78]
Ship hull
Energy loss
[79]
Water distribution pipe
Decreased disinfection, corrosion,
health threat
[3,4,6,76]
Petroleum reservoir
H 2 S souring, increasing refinery
cost, pipe clogging
[77]
Medical
Medical devices and
implants
Infection in medical devices and
implants, cystic fibrosis (CF) in
human lung
[7, 8]
Teeth
Dental plaque and cavity
[80]
 
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