Case Study 代写 A Critical Study Of Ballast Waters Management Environmental Sciences Essay

Case Study 代写 A Critical Study Of Ballast Waters Management Environmental Sciences Essay

A Critical Study Of Ballast Waters Management Environmental Sciences Essay

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Ballast water discharges are believed to be the leading source of invasive species in costal waters, thus posing public health and environmental risks, as well as significant economic cost to industries such as water and power utilities, commercial and recreational fisheries, agriculture, and tourism. By 2010, shipowners and managers who ship to North America must have a ballast water management system in place. At the moment most shipping companies are only in the process of developing ballast water management plan and do not have any ballast water systems in place. Furthermore, shipowners and managers also have to deal with the issues relating to retrofit of the system i.e. cost and ROI, space for the ballast water system, stability of ships during ballast exchange and ensuring that crew are adequately trained to handle the systems. Other member countries of the IMO are also expected to ratify the regulations in the next 5 years. This timely workshop will look at how ship operators can move forward in the most cost-effective and efficient manner.

The introduction of invasive marine species into new environments by ships’ ballast water, attached to ships’ hulls and via other vectors has been identified as one of the four greatest threats to the world’s oceans. The other three are land-based sources of marine pollution, overexploitation of living marine resources and physical alteration/destruction of marine habitat.

Shipping moves over 80% of the world’s commodities and transfers approximately 3 to 5 billion tonnes of ballast water internationally each year. A similar volume may also be transferred domestically within countries and regions each year. Ballast water is absolutely essential to the safe and efficient operation of modern shipping, providing balance and stability to un-laden ships. However, it may also pose a serious ecological, economic and health threat. 

What needs to be done to improve ballast water management?

IMO Treaty Ratification. The United States should ratify the IMO ballast water treaty. The IMO treaty represents the work product of ten years of consensus-building internationally. The United States should ratify the treaty and urge other countries to do so as well.

Ballast Water Treatment Standard. The United States should adopt an initial ballast water discharge standard consistent with the standard contained in the treaty. This standard should be subject to the same preimplementation review process outlined in the treaty,

which will adjust the standard after taking into account the availability of new treatment technologies and additional data collected during technology demonstration projects.

Aims and Objectives

Understand the behavior of ballast tank sediments and identify procedures to minimize the transfer of marine organisms.

Identify practical aspects of ballast exchange in terms of efficiency and study the effect of enclosing a natural community of microscopic marine plankton, including algae and animals, in a closed tank during the ship’s voyage.

provide an overview of the problem and describe the current state of play with respect to international ballast water regulations at IMO and ballast water management strategies being developed by the regional seas organizations within Europe

identify issues and technical difficulties related to developing and contributing to the strategies being developed by the Regional Sea Conventions, ratifying the IMO Convention and the processes being employed to help develop these controls.

Literature review

IMO Recommendations

A set of recommended actions have been adopted by IMO in relation to the uptake of ballast water. The taking in of ballast water in shallow habitats, during prevailing turbidity of water, nearby sewage outfalls, when a tidal stream is known to be more turbid, in areas where tidal flushing is known to be poor, during phytoplankton blooms or relevant disease outbreaks and near dredging sites have to be avoided to minimize the risk of up taking species. In addition ballast water should be wherever possible not be taken in darkness (when bottom dwelling organisms may rise up in the water column) and in very shallow waters or when propellers may stir up sediments.

Ballast water uptakes in port areas characterised by slow tidal currents could result in the uptake of ballast water formerly used by another vessel and just released. This scenario could enable some organisms discharged in the ballast water from one vessel to become transported again pumped in with the ballast water of another vessel.

It has been proposed that ballast water may be analysed in a laboratory on board and that the investigation may provide a certificate of cleanness of the ballast water documenting the absence of harmful aquatic organisms.

Dr. Stephan Gollasch, Removal of Barriers to the Effective Implementation of Ballast Water Control and Management Measures in Developing Countries. Available from: http://www.gollaschconsulting.de/download/IMO_report.pdf [Accessed 23 January 2010]

Ballast Water Exchange

Current ballast water regulations usually recommend minimizing the risk of introducing non-native species by exchanging ballast water in the open ocean.

This method is effective because organisms from coastal waters are unlikely to survive in the open ocean and vice versa. Drawbacks to this method are: (1) it is difficult to completely remove sediments and residual water from the bottom of ballast tanks; (2) organisms stuck to the sides of the tank or structural supports within the tank will not be readily removed; and (3) during stormy or rough seas it is unsafe for a ship to exchange ballast water. Thus, organisms remaining inside the ballast tanks may be discharged at a later time into ports and harbors if the exchange fails to remove all organisms.

There are also advantages to ballast tank exchange. Because it is done while the ship is en route, relatively little time is lost during the voyage. No additional equipment or operator training is needed for ballast exchange so the capital costs are low and it is a simple process to implement. Enforcement of ballast exchange laws can occur to some degree because open ocean waters have higher salinity levels than coastal waters and this difference can be detected by port authorities. In addition, Battelle, a research institution, is developing a quick and easy test for determining if ballast water exchange has occurred.

The effectiveness of ballast water exchange could be improved by redesigning ballast tanks and pumping systems. Currently, most ballast tanks have one pipe that pumps water in both directions, but not at the same time. With the addition of another pipe, ballast exchange could be achieved by continual flushing of the tank with one pipe bringing water into the tank and another pipe allowing water to exit the tank. This would be a safer means of exchanging ballast because the tanks would contain water at all times. Another means of improving current ballast tank flushing would be to remove the residual water and sediments from the bottom of ballast tanks. Pumps, which are relatively inexpensive, could be installed in the bottom of ballast tanks to remove these residual materials, thereby reducing the risk of introducing a nonnative species. Ballast tanks could also be redesigned with a sloping bottom or other structure that allows sediment and water to drain into a pump. Current ship designs often include structural supports and odd corners in the ballast tanks that trap organisms and ballast water. The possibility of trapping organisms in ballast tank structures could be reduced by

designing ships that do not have these structures, redesigning these structures so they do not trap ballast water and organisms, or by installing small pumps in these areas to remove water during ballast exchange.

Corrina Chase, Christine Reilly, and Judith Pederson, Ph.D. Marine Bioinvasions Fact Sheet:

Ballast Water Treatment Options. Available from:

http://massbay.mit.edu/resources/pdf/ballast-treat.pdf [Accessed 22 January 2010]

Chemical

Chemical biocides may be used to treat ballast water and prevent the introduction of non-native species. The specific type of biocide must be chosen very carefully to avoid harming humans or the environment. Biocides are usually shipped and stored in the form of a concentrated solid or liquid, so they can easily be stored

onboard a ship. These are widely used industrial chemicals, so much data exists on their safety and effectiveness, although reactions between biocides and sea water that could produce harmful byproducts have not been extensively studied. The machines for applying biocides are reliable and need little maintenance, but their size may be a limitation when installing them aboard ships. A major concern with the use of biocides is the safety of the crew members who handle the chemicals.

Because other dangerous chemicals that are used for lubricants and other functions on the ship must also be handled, training the crew to safely use biocides should be relatively simple. Another concern is whether residual biocides have the potential of corroding ballast tanks, pipes, pumps, and other structures.

Corrina Chase, Christine Reilly, and Judith Pederson, Ph.D. Marine Bioinvasions Fact Sheet:

Ballast Water Treatment Options. Available from:

http://massbay.mit.edu/resources/pdf/ballast-treat.pdf [Accessed 22 January 2010]

Filtration

Ballast water can be filtered before it enters the tanks or while it is being discharged. The advantage to filtering as water is pumped into the tanks is that organisms that are filtered out may be retained in their native habitat. If ballast water is filtered while being

discharged, proper disposal of organisms is required to eliminate accidental introductions. One of the main drawbacks to filtration is that it requires specialized equipment which may be expensive to purchase and install. The cost of filtration increases as smaller particles, and organisms, are removed from ballast water. Since the size of filters used to treat ballast water are not likely remove microorganisms, another treatment method would have to be used to remove microbial

invaders. New technologies are developing ways to increase the flow rate through filters and prevent organisms from clogging filters, making this method of treatment more useful.

The Algonorth experiment is a $1.3 million project in the Great Lakes that is designed to measure the effectiveness of ballast water filtration. A filtration nit, a testing laboratory, and peripheral equipment such as a trolley for towing a plankton net through a ballast tank were installed in 1996. A back washing mechanism cleans the filters and collects organisms to prevent their accidental release. In addition to removing larger organisms with the filtration method, another experiment will study which pathogens are carried in ballast water and evaluate whether filtration with fine-meshed filters removes pathogens.

Corrina Chase, Christine Reilly, and Judith Pederson, Ph.D. Marine Bioinvasions Fact Sheet:

Ballast Water Treatment Options. Available from:

http://massbay.mit.edu/resources/pdf/ballast-treat.pdf [Accessed 22 January 2010]

Other Methods

Other methods for treating ballast water are being investigated. These methods need much more research and development before they will be applied to ballast water treatment.

Ultraviolet (UV) light is currently used in hospitals, homeless shelters, and prisons to kill

microorganisms and prevent the spread of disease. UV lamps are being studied for use in municipal water treatment plants as a replacement for chlorine. This method is most effective on microorganisms, so would need to be combined with another method to effectively

remove all potential bioinvaders from ballast water. One of the main drawbacks is that UV light is ineffective in water containing suspended matter, so ballast water may need to be filtered before treatment.

Corrina Chase, Christine Reilly, and Judith Pederson, Ph.D. Marine Bioinvasions Fact Sheet:

Ballast Water Treatment Options. Available from:

http://massbay.mit.edu/resources/pdf/ballast-treat.pdf [Accessed 22 January 2010]

Methodology

Ships use ballast water to provide stability and maneuverability during a voyage. Water is taken on at one port when cargo is unloaded and usually discharged at another port when the ship receives cargo. Because organisms ranging in size from viruses to twelve inch fish living in the surrounding water or sediments are taken on board with ballast water, there is a potential for the introduction of non-native organisms – called bioinvaders, alien species, nonindigenous species or exotic species –

into the port of discharge. Ballast exchange costs are relatively low and involve development of ballast water management plans as well as increased pumping and fuel costs. Most crude oil tankers already have ballast water management plans in place.

No single ballast water management technique has been able to remove all organisms or all types of organisms from ballast tanks. A combination of different methods may prove to be more effective than one method alone, however little research has been conducted into this possibility. It is difficult to implement treatments because ship owners are understandably reluctant to install technology that is expensive, unreliable, or time consuming.

When evaluating ballast water treatment options a number of general factors must be considered including cost, enforcement, the effectiveness of the method, and the risks the treatment may pose to human health and the environment. The monetary cost of a treatment method includes the expense of the equipment, the crew needed to operate the treatment equipment, and the time needed for the treatment operation. Many treatment methods require that ships be retrofitted with the necessary equipment or that new ships have the equipment included in their design, both of which may be quite expensive. Because crew members have many tasks to perform on a ship, any crew that is needed to operate the treatment may decrease the number of crew members that are available for other ship operations. If a treatment method slows down the journey of a vessel or causes excess fuel consumption the journey will be more expensive. Any treatment method should provide means for port authorities to easily monitor whether or not the treatment has been performed and if it was effective.

This allows for enforcement of any laws regarding ballast water treatment. Because many treatment methods work by killing the organisms in ballast water, the method itself may pose a risk to human health or to the environment if the treatment is not properly contained in the ballast tanks. These risks and costs need to be evaluated and compared to the risk of introducing species to a port.

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