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CALMING THE WASHWATER DEBATE

Monday, January 27, 2020 

Regulations governing the release of sulphur oxides, also known as SOx, into the atmosphere will become a reality on 1 January 2020 and most operators have opted to use low- sulphur fuel to comply with the new rules.

Around 5% of owners have, however, opted to use exhaust gas cleaning systems (EGCS), or scrubbers and the washwater from these systems is causing consternation among the regulators, with calls from a number of organisations for further regulation to curb the discharge of scrubber washwater from vessels fitted with open loop scrubbers.

Open loop scrubbers collect sulphur and other pollutants from the exhaust and the collected pollutants, rather than being discharged into the atmosphere are released into the ocean. Many scrubbers have a closed loop system where the collected pollutants are stored on board and dealt with at a port, while others have hybrid, closed and open loop systems. For some industry observers, the washwater from scrubber technology is seen as a possible new source of pollution and will require further regulation to prevent the pollution of the seas. This is because the washwater from onboard scrubbers will contain heavy metals such as cadmium and lead as well as other pollutants such as PAHs (Polycyclic aromatic hydrocarbons) anthracene, fluoranthene and naphthalene, among other chemicals.

At the most recent Marine Environment Protection Committee, (MEPC74), of the International Maritime Organization (IMO), the Japanese delegation presented a report based on expert research on washwater that logged the expected environmental impact of scrubbers on the oceans. That report concluded that there would be little effect on the marine environment. That research conducted by experts commissioned by Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) has concluded that there is no serious danger from the discharge of scrubber washwater into the oceans, not only in the short-term, but over the long term and in the wider marine environment.

According to the report, which was published earlier this year, there is no “scientific justification to prohibit the use of open-looped (sic) scrubbers, as long as the IMO’s discharge criteria were met”.

Speaking exclusively to Clean Shipping International, the MLIT report co-ordinator Naohide Saitoh says: “The conclusions of the paper were that the heavy metal, PAHs and SOx in the washwater do not pose any serious harmful effects on the marine environment as the levels were quite low.

“We don’t need to care about the amounts as the detection levels were too low to worry about.”

In its washwater report, MLIT assumed that all ships were fitted with open-loop scrubbers and the researchers intentionally studied the comparatively enclosed areas of the Seto Sea, Ise and Tokyo Bay. Using details on washwater deposits from ships fitted with open-loop devices researchers were able touse AIS data to estimate the number of ships visiting the regions over a 10-year period and to calculate the accumulated concentrations of harmful substances.

Given that only around 5% of ships have currently been fitted with scrubbers, the calculations are considered to be substantial over-estimates of the actual deposits expected over a decade, explained Saitoh.

At MEPC74, Japan concluded that the risk of harmful concentrations of pollutants from washwater was “in the acceptable range of negligible”, both in the long and short term and that based on this study Japan will not apply restrictions on open-loop scrubbers in its waters.

Results from Japan’s research project are very similar to the initial conclusions drawn by consultants CE Delft and Deltares in their study of exhaust gas cleaning systems (EGCSs) called The Impacts Of EGCS Washwater

Discharges On Water Quality, which was also submitted to this year’sMEPC74 in May. This report is aimed at assessing the impact of washwater discharges at the berth, with a focus on the Baltic and North Seas.

According to the initial findings of the CE Delft/Deltares report, the impact of washwater from EGCSs would “increase the equilibrium concentration in the port by no more than 0.025% of the annual average 2021 environmental quality standard in the EU.”

Annual average harbour accumulated concentrations are calculated as a percentage of future expected averages, in 2021, and the allowable concentrations laid down in the EU Directive 2013/39/EU, concerning pollutants in surface waters, both inland and in the wider seas and oceans.

Initial results from the European consultants will be followed by further research into two more generic ports in the North Sea and Baltic regions, comparing a range of potentially hazardous compounds against the IMO criteria for washwater from EGCSs as well as comparing concentrations in river and sea water.

Meanwhile, a third study conducted by cruise ship operator Carnival Corporation is an ongoing analysis of washwater from 23 cruise vessels testing for 54 separate parameters, including PAHs and heavy metals.

Samples are taken from three points, the EGCS inlet, the tower and the outlet. Carnival said that an expanded data base included samples from 11 vessels that were fitted with washwater filtration systems, samples were also taken from the point immediately before the water entered the filter.

However, the researchers pointed out that the positive results from the vessels fitted with filtration systems particularly for certain compounds, such as anthracene, benzo(a) anthracene, benzo(b)fluoranthene, arsenic, copper and many other substances, the number of ships in the study with filters was just 11 and as such there would need to be further tests, including operational trials, to determine the effectiveness of filtration.

Nevertheless, the company concluded that washwater concentrations were below the emission limits for land-based industry. However, the report cautioned: “This is not evidence of compliance with these standards (which are intended for a different regime and include other controls and limits for compliance). The comparison does, however, establish a point of reference to understand the quality of the EGCS washwater relative to other industrial discharges.”

Even so,the report also pointed out that the washwater concentrations measured from the cruise ships also compared favourably with tougher environmental regulations such as the EU Surface Water Standards for inland waters. The analysis again pointed out that these EU rules were designed for a very different application, but said “they provide a useful quantitative reference” in understanding the washwater concentrations, particularly for compounds such as PAHs where “there is a lack of more suitable standards”.

Results also pointed to low concentrations of certain compounds such as arsenic, cadmium, lead, mercury, selenium and thallium.

While useful, the Carnival study does have some acknowledged limitations. These include the statistics provided are averages of all the vessels in the study rather than individual results for each ship.

In addition, Carnival points out that the study only offers an insight into washwater quality as a basis for a more informed, industry-wide debate.

It does not assess the cumulative effects of washwater discharges and neither does the research offer an insight into the wider environmental impacts of those discharges.

Results from the Carnival and CE Delft/Deltares research projects, while inconclusive, offer an insight into the levels of concentrations that could be emitted from vessels using scrubber technology to meet new IMO 2020 regulations. The broader study by MLIT shows that the wider effects of washwater discharges are unlikely to pollute the oceans significantly.

Whether Japan and other countries can use this evidence to successfully argue this case at an IMO that is keeping one eye on the wider population and its opinion remains open to question.

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