Biofouling is one of the major challenges faced by the shipping industry. Biofouling results in decrease in the speed of the ship, increase in the burning of fuel, and the resultant greenhouse gas emissions. To understand these challenges, one must understand Biofouling.
What is Biofouling?
Biofouling is the undesirable accumulation or colonization of bacteria, barnacles, algae, and other sea animals on submerged wet surfaces of the ship. Shipping and leisure vessels, heat exchangers, oceanographic sensors, and aquaculture systems are greatly impacted by Biofouling.
The existing remedy to fight Biofouling is an approach called Antifouling, which is the process of removing the accumulation of organisms and preventing such accumulation. This is accomplished by coating the submerged areas of the ships with antifouling coating. The system is based on the controlled release of biocides to kill the colonizing organisms. However, due to the increased environmental restricts placed on biocides and their use, there is a need for developing newer, non-toxic coating methods to accomplish this task. To achieve this goal, and introduce novel technologies to control Biofouling, an R&D project, Advanced Nanostructured Surfaces for the Control of Biofouling (AMBIO) has been designed.
The AMBIO project is a collaboration of diverse disciplines and partners. While the disciplines include nanotechnology, polymer science, surface science, coating technology, hydrodynamics, and marine biology, the partners represent industries, universities, research organizations and end-user stakeholders.
Problems caused by Biofouling
As we understand the overall problem of Biofouling, detailed information is required to gauge the impact of Biofouling.
- Accumulation of unwanted bacteria on the submerged surfaces of the ship results in the increase of frictional drag. This reduces the speed of the ship by more than 10%.
- A fouled ship burns 40% more fuel which increases the fuel cost.
- An increase in burning of fuel results in more emission of greenhouse gases. This is estimated to be 20 million tons per annum.
- Fouled ships disturb the balance of sensitive ecosystems by spreading alien species around the world.
- Biofouling affects the coastal and oceanographic measuring instruments, which are used in marine and coastal research and monitoring programmes by reducing the data quality and instrument performance. The manual cleaning by divers to combat Biofouling is very expensive.
- Desalination and power plants face an overall decline in efficiency and increase in cost due to fouled intake structures, screens, seawater piping systems, and heat-exchanger tubes. For example, the presence of a biofilm on transfer surfaces of heat exchangers cooled by seawater reduces the heat transfer rate by 20 to 50% and incurs a global expenditure of over $15 billion per annum to control the problem.
- Fouling in the area of membrane technology, microfiltration, and ultrafiltration leads to significant decline of the permeate flux, higher energy consumption, and failure to meet the regulatory standards in the long run.
- Farm infrastructure such as immersed cages, netting and pontoons, onshore equipment such as pipelines, pumps, filters, and holding tanks. This leads to an annual cost of €96000 per annum per farm for small shellfish producers.
The AMBIO Project
The AMBIO project aimed at developing a new coating that will prevent or reduce the adhesion of fouling organisms through the physio-chemical properties of the surface rather than the release of biocides. Since the organisms are on a micro-scale dimension, studying them with the help of nanotechnology becomes imperative. For this, research on nanoscale interfacial properties of different properties of different surfaces, how organisms adhere have to be studied. Nanostructuring of a coating controls many surface and bulk properties that are relevant to an antifouling, non-sticky surface such as surface energy, charge, conductivity, porosity, roughness, moisture, friction, modulus, physical and chemical reactivity, and compatibility with organisms. Another goal of the project was to study the influence of surface properties on the adhesion process of fouling organisms.
Results of the AMBIO Project
The AMBIO project has been successful in understanding and developing newer and innovating methods to fight Biofouling such as the following:
- Developed 500 different nanostructured coatings representing 64 generic coating chemistries on a laboratory scale, for evaluating their antifouling and fouling release performance. Further, 15 underwent end-user tests. Several coatings have been commercialized and the others are being studied for further development.
- Applied surface sensitive tools developed as part of the project to the study the nanoscale properties of coatings and their changes during immersion.
- Made advances in understanding the influence of surface nanostructure on the settlement and adhesion of fouling organisms.
- Developed the concept of ambiguous coating on the premise that that an appropriate level of heterogeneity and pattern, in topography, or in surface chemistry, may be more effective than a homogeneous surface.
- Developed novel methods for nanostructuring surfaces for use other than antifouling.
- Understood the relationship between the structure and properties of a coating and its biological performance.
- Established Hydrodynamic properties of several candidate nanostructured coatings.
- Developed and applied novel imaging methods including digital holography and imaging Surface Plasmon Resonance for the first time to analyze how the fouling organisms explore surfaces and how the coating properties affect this.
- Exchanged knowledge and technology amongst partners working in different disciplines, and between academia and industry.
- Established new enterprises and cooperative projects.
- Submitted patent applications for five coating technologies.
- Published 70 papers in international journals.
- Informed the general public, coating industry, and research community about nanotechnology and its potential for accelerating the introduction of green and sustainable technologies through 531 items of individual dissemination.
Benefits of the AMBIO Project
With the success of the AMBIO project has provided several benefits to the Industry, Research sector, Environment, Socio-Economic sector, and the European Research Area.
- Development of cleaner and renewable technologies
- Reduction of energy losses, consumption of fossil fuels, greenhouse gases
- Establishment of new networks of collaboration promoting knowledge transfer in the EU industries
- Benefit of the competitive edge to the EU industries
- Encouragement to continue the research for novel technologies further
- Acquisition of three successful patent applications for new coating technologies
- Development of research and publication material