Protecting aquatic ecosystems

Martin Binney

December 23rd, 2021

Martin Binney

Global Product Line Manager,
Recording and Control

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While ships are a highly effective way of carrying cargoes around the world, they can also provide a way of transporting pollutants – both man-made and biological – that can be damaging to the environment if left unmanaged. We look at how ABB’s instruments and analyzers can be used to help protect the world’s ocean and coastal environments by tackling the problems of bilge and ballast water.

When we think of marine pollution, the things that spring immediately to mind might be engine emissions or oil leakages into the sea.

Yet there is another form of ‘pollution’ that ships can be responsible for – biological pollution that results in invasive life forms being transported around the world and released into new sea areas, disrupting the local ecosystems.

It’s all down to ballast water and how it is used and released. Ballast water is pumped aboard vessels to maintain safe operating conditions throughout a voyage. It offers several benefits - reduces stress on the hull, improves stability, improves propulsion and manoeuvrability and compensates for weight changes throughout the voyage.

The problems occur when ballast water ends up being discharged in a completely different part of the world. Plankton, bacteria, plants and molluscs can all end up in a new environment.

Invasive species can out compete native ones, alter ecosystems and change coastal landscapes.  Did you know there is even a Japanese sea worm that has neurotoxins more powerful than arsenic or cyanide?

To prevent these damaging invasions, ships are required by the IMO to have an approved Ballast Water Management Plan or BWMS. They must carry a ballast water record book and carry out ballast water management procedures to a given standard. The cleaning and discharge of bilge water is also regulated and the composition and location of both ballast and bilge water discharges must be recorded and reported.

The MARPOL regulations set a maximum limit of 15ppb for oil concentrations in bilge water for it to be discharged into the sea. The regulations also govern the discharge of wastewater from other parts of the ship such as scrubber sludge.

A typical system for treating ballast water would include a physical separation step, which filters out sediment and the larger organisms and returns them to the original ballast site. This could be followed by another disinfection technology to remove pathogens and the sneaky smaller organisms missed in the first stage.

Put simply, ships using a BWMS must meet a performance standard based on agreed numbers of organisms per unit of volume. A key requirement under the plan is the reporting of ballast and bilge water discharges – this must include details of when and where water was discharged, how much was released, as well as its salinity and temperature.

And non-compliance can be pricy - under the United States National Invasive Species Act, ship owners can be fined over $38,000 for discharging ballast water without an approved BWMS.

Measuring volumes of discharged water is a key part of the process, but one of the problems is the water to be measured – or rather, what’s in the water. Ballast water will contain mussels, sand and other particles, potentially clogging up any conventional, mechanical flow meters earmarked for the job. This limits the lifespan of the meter and requires increased maintenance and more frequent replacement.

By contrast, ABB’s ProcessMaster electromagnetic flowmeter has no moving parts reaching into the pipe that can wear and cause pressure loss. It also adds a highly abrasion resistant sensor liner to toughen it up still further.

And while measuring the flow of water, you’ll need some method of recording – this is where ABB’s RVG200 paperless data recorder comes in. This features a GPS location function, which logs the ship’s GPS co-ordinates alongside data on ballast and bilge water discharge volume and quality, so the ship can prove where it was when a volume of water was discharged.

The RVG200 is ideal for recording bilge well level, holding tank level, bilge alarm status, bilge pump status and bilge discharges. The recorder shows the whole process and puts all the relevant data at your fingertips on a touchscreen.

Getting to grips with the quality of ballast water is also vital. ABB offers a full range of sensors and transmitters, including digital options, for measuring multiple parameters including the pH, conductivity and turbidity of ballast and scrubber water.

Recent rule changes on BWMS will help prevent any further damage to biodiversity from ballast water discharges – and using ABB solutions can go a long way to meeting these rules and protecting the precious marine environment.

Smoother sailing on the Seven Cs

The topic of coastal protection is just one of the Seven Cs in our marine campaign, which covers key areas where ABB’s measurement technologies and service and support can help marine operators and shipping companies to optimize their performance whilst minimizing their environmental impact.

For more watch our Seven Cs TechTalks webinars

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