From selecting to operating a BWMS, shipowners need to understand the technology and the regulations, say Penelope Cooke and Conan O’Driscoll of Brookes Bell*
Ballast water management systems (BWMSs) already on the market treat the water using chemicals known as active substances (such as chlorination, oxidation and biocides), or physical processes (such as filtration, UV, heat and electrolysis) or a combination of both.
Provided the BWMS meets or exceeds the D-2 performance standard of IMO’s Ballast Water Management Convention (BWMC), either treatment process is acceptable because the performance standards for IMO and US Coast Guard (USCG) are the same. Where differences occur is in equipment testing and verification protocols: IMO guidelines do not require independent testing, whereas the USCG specifies mandatory type-approval testing that is independent from manufacturers.
Some owners of existing vessels have chosen to decouple their IOPP renewal survey from the Harmonised System of Survey and Certification (HSSC), taking advantage of the requirement to comply with the BWMC only by the first IOPP renewal survey after 8 September 2019.
As a result, BWMS installation dates could be up to six years from now, meaning the age of a vessel – and the effect on its value such a system would have – may need to be taken into account. Typical planning and pre-engineering times are advertised at between six months and one year, hence retrofitting BWMSs on existing vessels is likely to be the predominant focus for the foreseeable future.
A BWMS includes not only the ballast water treatment equipment, but also its associated control equipment, manufacturer-specified piping arrangements, control and monitoring equipment, and sampling facilities. An understanding of the functionality and usability of BWMSs may be valuable in deciding which one is selected, and owners would do well to consider the following when choosing:
• Technology: Is it proven to be reliable? Are the processes used robust?
• Size: Where will it fit? Can it be easily maintained?
• Availability: Consider availability of spare parts and service technicians.
• Vessel trading pattern: What types of water will it operate in? Will the water’s turbidity affect the system’s operation?
• Availability of system consumables: These will need to be ordered, and in sufficient quantity for voyages where such consumables are not available.
• Crew training and crew workload: Despite claims that some systems require ‘minimal crew interaction,’ we believe crew must maintain responsibility for checking the system regularly during a voyage, specifically during ballast water exchange.
• Power consumption: Is an additional generator required?
• Ballast tank coatings: Will the chemicals affect tank coatings?
• Futureproofing: Some systems will become obsolete, so consideration should be given to their interchangeability.
The BWMC details three ballast water exchange methods – sequential, flow-through and dilution – that deal not only with ballast water but with accumulated sediment in the tanks, which must also be flushed out. All qualifying vessels will ultimately need a compliant ballast water management plan (BWMP) and a ballast water management certificate or statement of compliance.
The BWMP should include the duties of key shipboard personnel undertaking ballast water tasks, all of whom should be fully conversant with the system’s safety aspects. To reduce potential compliance issues, ballast water records must be accurately maintained, and the BWMP should be able to be clearly demonstrated on board during any inspections.
Part of the duties associated with operating any BWMS relate to whether it uses chemicals, or ‘active substances,’ given their risk to the environment, human health, property or resources. Active substances are intended to be toxic, so appropriate safety controls on their storage and handling are required. It is prohibited to discharge such chemicals into the sea.
*Dr Penelope Cooke is an associate and consulting scientist and Conan O’Driscoll is an associate and marine engineer, both at the marine technical and surveying consultancy Brookes Bell Group
Why is our BWMS not working?
Checking compliance of the ballast water management system (BWMS) against manufacturers’ specifications and test certificates, along with crew training, will become essential to keep systems operational.
One problem already being highlighted is the effect of active substances on paint coatings inside ballast tanks, specifically where these are affecting the corrosion and coating requirements of ballast tanks.
“Brookes Bell’s expertise in investigating non-compliance in maritime systems is known globally,” Dr Cooke and Mr O’Driscoll told BWTT. It has extensive experience providing expert witness evidence in court and arbitration when things have not gone to plan. Brookes Bell also has experience selecting suitable systems and preparing installation plans, they added.