The Ballast Water Management Challenge Solutions to a Global Environmental Problem

David A. Wright, University of Maryland, Center for Environmental Science, Environmental Research Services Thomas P. Mackey, Hyde Marine, Inc.

[Note that this material is excerpted from a series of papers being prepared by the Ballast Water Expert Group (BWEG) of the Institute of Marine Engineering Science and Technology (IMarEST). The authors are the co-chairs of the BWEG.]

It has long been recognized that ballast water represents the primary vector for the introduction of invasive aquatic organisms into waterways and coastal ecosystems. Invasive species threaten not just the balance of the ecosystems themselves but may also degrade coastal and inland fisheries, through encroachment by non-commercial species, and industrial and municipal water usage through the clogging of intakes by species such as zebra mussels. Introductions of some phytoplankton species through this vector can involve potentially serious health risks. Prominent among these has been the proliferation of harmful algal blooms resulting from ballast water transport of phytoplankton between coastal areas.

The transoceanic transport of non-indigenous species was the focus of the 2004, United Nations International Maritime Organization (IMO) Ballast Water Management Convention (BWMC) mandating international ballast water management. After 2016 all vessels subject to the regulations will be required to have an operational, IMO type approved ballast water management system. Some jurisdictions may apply stricter standards. The current standard sets limits on the number of viable organisms allowed in treated discharged ballast water. The standard includes different size categories and makes provision for both bacteria and more complex planktonic organisms.

One of the greatest challenges imposed by the BWMC and the requirement to fit type approved Ballast Water Treatment Systems (BWTS) is finding space and power and managing the installation onto existing ships. New vessels can deal with the challenge through proper planning and providing adequate space and power for a treatment system. The major challenge for new buildings may be the availability of suitable IMO Type Approved BWTS. Currently 10 systems have received type approval under the IMO G-8 Guidelines. Additional approvals are expected soon.

A system must be chosen that is well suited to the particular vessel whether it is a retrofit or new construction. Because of the significant investment involved, an established supplier offering a technology with proven operational reliability, as well as IMO type approval should be chosen. The system must be compatible with the existing or planned ballast system and generally must be suitable for operation in salt, brackish and fresh waters. Particularly in the case of retrofits, the system should be designed for adaptability with modular components for installation flexibility and preferably suitable for transport through existing accesses. The owner/operator and supplier need to work closely with the installers and the Classification Society. There are many special considerations particularly for ships on which the system must be installed in hazardous areas or that have very high ballast water flow rates. Because of the tight compliance schedules, the availability of installation facilities, skilled fitters and engineering services may be among the greatest impediments to meeting the BWM Convention requirements for existing ships.

Many other engineering, installation and operational challenges must be met on vessel retrofits including determining the effect of the added pressure drop on the ballast pump’s capacity. Normally a ship check will be required to determine the most suitable location for the system components and to develop the necessary engineering information and drawings to meet the owner and class requirements. Safety, reliability, maintainability, automation, and low operating costs, energy consumption, and consumables throughout the life of the ship are among the principal operational considerations.

As the BWMC advances towards full ratification by IMO member states, the size and scope of the management task becomes increasingly clear. The Convention will come into force exactly 12 months following full ratification. Many observers expect full ratification of the convention in 2012 or sooner.

The worldwide commercial fleet has been estimated at approximately 70,000 vessels. Ballast capacities range from several cubic meters (m3 or tonnes) in the case of fishing boats to hundreds of thousands of tonnes on very large bulk carriers, where ballasting rates can be as high as 15,000–20,000 m3/h. In many multiple BWTS may be required, depending on the number and configuration of ballast pumps and for larger vessels with very high ballast capacities and flow rates. Installation of BWTS has been scheduled according to a 4-year timetable, depending on the capacity of the ship and its age. Assuming full compliance by the existing merchant fleet, and an expected 2,000 new ships entering the world’s fleets each year, it has been estimated that the global BWTS market will spike during years 2012 to 2015 with over 10,000 existing ships per year (30 per day) installing BWT systems, and will then drop sharply in 2016, when it is assumed that all existing vessels will be in compliance and the annual market will be represented only by new ships (King and Hagan 2011). Given the enormity of the task some slippage in these dates would not be surprising. In addition to the daunting task of equipping the world commercial fleet with BWTS there is the formidable job of enforcing the statute circumscribed by the convention once it comes into force.

Although performance testing has become increasingly standardized world-wide and has become the ‘blueprint’ for future compliance testing, an important distinction between the two will be that, performance testing typically compares treated with untreated water, compliance testing will deal exclusively with the discharge of treated water from vessels as they enter port. This challenge is just now being dealt with at IMO.

In view of the fact that enforcement of the convention will be the responsibility of the port states it is likely that jurisdictions will adopt a tiered approach to compliance assessment, including the use of reporting, inspections, and testing for selected groups of organisms. Such a strategy would identify the most obvious cases of noncompliance, based on the rationale that is much easier and cheaper to detect clear noncompliance than it is to identify full compliance, bearing in mind the sampling and analytical effort involved.

The complexity of the issue and the need for a relatively uniform approach to this worldwide challenge will require a sustained effort to standardize outstanding sampling and analytical protocols and streamline the testing process. This in turn will provide a cost effective means for enforcing the ballast water management convention and reversing the exponential increase in aquatic invasive species introductions worldwide.

All ship owners will have to comply with the upcoming BWM regulations. The IMO BWM Convention is expected to be ratified shortly and will come into force 12 months after ratification. Planning immediately for the installation of BWTS and selecting safe, practical, robust and reliable ballast water management solutions should be the highest priority.

King, D.M. and Hagan, P. (2011). "The question industry should ask IMO about ballast water.”
Sustainable Shipping April 20, 2011.