25 Environmental and Economic Impacts of Biofouling on Marine …
391
Category 3: Environmental issues associated with the process of biofouling mitigation or removal
Currently, there are many technologies employed in the industry for the prevention or the mitigation of biofouling in marine heat exchangers. The companies use
online biofouling prevention techniques, offline biofouling prevention techniques or
a combination of both (Müller-Steinhagen et al. 2011). The technique that will be
adopted depends on several factors like the type of heat exchanger, type of fouling,
severity of the fouling, cost and expenses related to the biofouling prevention technique, plant operational characteristics, the production capacity of the plant, seawater
conditions, environmental regulations, climate conditions of the region where the heat
exchanger is functioning and so forth. (Müller-Steinhagen et al. 2011). In the case
of online techniques, the cleaning or removal of biofouling from heat exchanger
surfaces is done without removing the heat exchanger from its current operation
(Müller-Steinhagen et al. 2011). But in offline cleaning, heat exchangers have to be
moved out of the current operation (Müller-Steinhagen et al. 2011).
A widely used online technique for the mitigation of marine biofouling in the
industry is the application of chemical agents like biocides, antiscalants or antifouling
agents (Kronholm 2018;Müller-Steinhagen et al. 2009). The dosage of these chemicals mainly depends on the type and the severity of fouling. These chemical agents
can reduce the growth and deposition of biofoulants on heat exchanger surfaces.
But, at the same time, they contain considerable amounts of chemicals like chlorine, polyphosphate, hypochlorite, coagulants bromine, zinc, among others (Kazi
2012). If the application process of chemical agents is not properly monitored, it
could result in the release of chemicals to seawater. This leads to seawater pollution and affects marine life. It also leads to the violation of important environmental
legislation such as Water Framework Directive 60/2000/EC of the European Union
(Müller-Steinhagen et al. 2009, 2011).
A popular offline cleaning technique is the mechanical cleaning of heat exchangers
using manual labour and chemicals. The removed fouling matter after the cleaning
process could contain harmful bacteria, fungi, carcinogenic/radioactive matter &
other microbial particles (Müller-Steinhagen et al. 2009). Improper disposal of
these ‘removed fouling matter’ as well as the ‘toxic chemicals used in the cleaning
process’ cause severe environmental pollution and health issues (Müller-Steinhagen
et al. 2009). For example, the removed fouling matter could have the presence
of Legionella (a pathogenic group of Gram-negative bacteria) (Bott 2006; Flemming 2002). Biofilms are known sources of Legionella pneumophila which causes a
pneumonia-type illness called Legionellosis (Abdel-Nour et al. 2013). In addition to
that, the inappropriate handling of chemicals while usage also results in safety issues
(for example, burns) due to exposure to chemicals (Müller-Steinhagen et al. 2011).
The research study provides clear evidence that biofouling in marine and coastal
heat exchangers lead to severe environmental, climate as well as health issues.
391
Category 3: Environmental issues associated with the process of biofouling mitigation or removal
Currently, there are many technologies employed in the industry for the prevention or the mitigation of biofouling in marine heat exchangers. The companies use
online biofouling prevention techniques, offline biofouling prevention techniques or
a combination of both (Müller-Steinhagen et al. 2011). The technique that will be
adopted depends on several factors like the type of heat exchanger, type of fouling,
severity of the fouling, cost and expenses related to the biofouling prevention technique, plant operational characteristics, the production capacity of the plant, seawater
conditions, environmental regulations, climate conditions of the region where the heat
exchanger is functioning and so forth. (Müller-Steinhagen et al. 2011). In the case
of online techniques, the cleaning or removal of biofouling from heat exchanger
surfaces is done without removing the heat exchanger from its current operation
(Müller-Steinhagen et al. 2011). But in offline cleaning, heat exchangers have to be
moved out of the current operation (Müller-Steinhagen et al. 2011).
A widely used online technique for the mitigation of marine biofouling in the
industry is the application of chemical agents like biocides, antiscalants or antifouling
agents (Kronholm 2018;Müller-Steinhagen et al. 2009). The dosage of these chemicals mainly depends on the type and the severity of fouling. These chemical agents
can reduce the growth and deposition of biofoulants on heat exchanger surfaces.
But, at the same time, they contain considerable amounts of chemicals like chlorine, polyphosphate, hypochlorite, coagulants bromine, zinc, among others (Kazi
2012). If the application process of chemical agents is not properly monitored, it
could result in the release of chemicals to seawater. This leads to seawater pollution and affects marine life. It also leads to the violation of important environmental
legislation such as Water Framework Directive 60/2000/EC of the European Union
(Müller-Steinhagen et al. 2009, 2011).
A popular offline cleaning technique is the mechanical cleaning of heat exchangers
using manual labour and chemicals. The removed fouling matter after the cleaning
process could contain harmful bacteria, fungi, carcinogenic/radioactive matter &
other microbial particles (Müller-Steinhagen et al. 2009). Improper disposal of
these ‘removed fouling matter’ as well as the ‘toxic chemicals used in the cleaning
process’ cause severe environmental pollution and health issues (Müller-Steinhagen
et al. 2009). For example, the removed fouling matter could have the presence
of Legionella (a pathogenic group of Gram-negative bacteria) (Bott 2006; Flemming 2002). Biofilms are known sources of Legionella pneumophila which causes a
pneumonia-type illness called Legionellosis (Abdel-Nour et al. 2013). In addition to
that, the inappropriate handling of chemicals while usage also results in safety issues
(for example, burns) due to exposure to chemicals (Müller-Steinhagen et al. 2011).
The research study provides clear evidence that biofouling in marine and coastal
heat exchangers lead to severe environmental, climate as well as health issues.