The final episode of BBC’s Blue Planet II, that aired in December last year, had a deep impact on its viewers. The documentary showed unsettling images of albatross feeding their chicks plastic and dolphin calves exposed to toxins from their mother’s milk. David Attenborough in his final address made severe observations: “The oceans are under threat now more than ever before in human history. The future of humanity and of all life on earth now depends on us,” he said.
Now there is growing public pressure and it is influencing decision-makers and regulators, including the International Maritime Organization (IMO).
“The whole world is looking at it more. There’s a heightened awareness of what’s going on,” says Jason Hardy, head of sales for Wärtsilä’s Advanced Waste Treatment Systems Retrofit business, speaking of the interest in the health of oceans. “The environmental regulations will only get more stringent. It’s only going to go one way, that is, towards zero-emissions.”
According to Tom Jilbert, a marine biogeochemist at the University of Helsinki, the Baltic was one of the first polluted seas in the world to generate public concern, with alarm rising throughout the 1970s.
“By around the 1980s, the water quality of the Baltic Sea had declined significantly, the oxygen concentrations had declined in the deep areas and we started to see more of these harmful algal blooms,” he says.
The sea’s size, its low level of water exchange with the North Sea and the density of surrounding industry and agriculture made it unusually vulnerable.
“It’s generally regarded as one of the most human-impacted marine systems and that’s because there’s a relatively high population density in the catchment area and some highly industrialised countries,” explains Jilbert.
“And then it’s a relatively small and shallow sea, which means that it accumulates high concentrations of nutrients or other pollutants that go in,” he adds.
To protect the waters, the Baltic Marine Environment Protection Commission (Helcom) was set up in 1974 and in 2007 it adopted the Baltic Sea Action Plan. Under this plan, the countries surrounding the sea promised to make major reductions in the quantities of phosphorus and nitrogen entering the sea from agriculture and other activities in the hope of reducing algal blooms.
“In some cases, the nutrient inputs have been reduced significantly,” says Jilbert. “But there is a time lag. I am confident that if the targets are met, the systems will improve. However, with the current models, it’s hard to say how many years or decades it will take.”
From January 2019, all newly-built ships that want to operate in MARPOL Annex IV special areas, such as the Baltic, will have to meet emission limits on phosphorus and nitrogen in wastewater that has been treated to be discharged. By 2021, all existing ships will also need to comply with this limit.
The IMO has also taken measures to reduce the entry of invasive species. Untreated ballast water released at the ship’s destination could potentially introduce a new invasive marine species that can have devastating consequences for the local ecosystem. This has been the cause of damage to marine ecosystems globally for some time now.
On 8 September 2017, the Ballast Water Management (BWM) convention finally came into force. Under this treaty, all ships in international traffic are required to manage their ballast water and sediments and maintain a certain standard based on ship-specific ballast water management plans. All ships are required to carry a ballast water record book and an international ballast water management certificate.
Ballast water management standards are being phased in over a period of time as well. Currently, every ship that is over 400 Gross Registered Tonnes (GRT) has to install a type-approved treatment system to kill plant and animal life in ballast water at its next mandatory International Oil Pollution Prevention Certificate (IOPP Certificate) renewal survey.
The IOPP certificates are also issued to new ships after a surveyor has inspected it and found it to be in compliance with the MARPOL convention. This means new ships have to comply with the BWM guidelines as well.
As a result of the IMO wastewater regulation, also known as the ‘paragraph 4.2’, Wärtsilä has seen strong demand for its latest Membrane Bio Reactor (MBR).
The advanced wastewater treatment system (AWWT), which is capable of removing nitrogen and phosphorus, is being used to meet legislative demands of special areas.
Removing nitrogen from wastewater requires adding an anoxic zone to the standard bio reactor, allowing the bacteria needed for this biological process to effectively remove nitrogen within the biomass.
For existing ships that require upgrades or retrofitting, this means either finding space on board for a new tank or re-designating parts (or the whole) of an existing ship’s structural tank to increase the volume for the biological process to effectively remove nitrogen.
To remove the phosphorus, the water is dosed with alum (hydrated aluminium sulphate) during the aerobic digestion stage of the process.
“In the next year or two, it’s going to be very busy,” says Hardy. “We’ve already seen requests coming in thick and fast for upgrading and retrofitting to meet incoming standards.”
Most customers, especially cruise companies such as the Carnival brands, are going one step further and installing larger systems to treat their vessels’ ‘grey water’, which comes from showers, sinks, laundry machines and the galley, as well as ‘black water’ containing sewage.
“They (customers) have come to me and said, ‘If we’re going to do an upgrade to our system, we want to futureproof it so that we don’t have to do it again in the next five to ten years when the legislation gets even tighter’,” says Hardy.
“From a future perspective, we believe this will be the next step. Much like the current legislation in Alaska, ‘grey water’ will need to be treated in the Baltics as well,” he adds.
