Feature 4 | SHIPBOARD WATER TREATMENT Winning the faecological battle


New regulations that came into force in January governing the release of treated effluent from vessels has raised the requirements from merely diluting black and grey water to actively reducing the pollutants. A slew of options are available to owners for the treatment of effluent that will help operators comply with the new rules


the release of treated waste water from ships and was adopted on 5 October 2012, has arisen with the IMO clarifying the situation as following flawed interpretations from a number of sources. According to the IMO the resolution MEPC 227(64) did come into force on 1 January 2016 and all its requirements will be enforced from this date except the elements concerning the concentrations of phosphorous and nitrogen, MEPC (69), which takes place in April, will consider the entry into force dates and an announcement on that issue should be expected following that meeting. Essentially MEPC 227(64) will apply to


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sewage treatment plants installed on or aſter 1 January 2016 on ships, other than passenger ships, in all areas and passenger ships outside MARPOL Annex IV special areas. Currently the only ‘special area’ designated is the Baltic Sea, though there is an expectation that new areas will be stipulated in the near future. Te requirements of these Guidelines,


including those in section 4.2, will apply to sewage treatment plants installed on new passenger ships when operating in a MARPOL Annex IV special area and intending to discharge treated sewage effluent into the sea on or aſter 1 January 2016 and on existing passenger ships when operating in a MARPOL Annex IV special area and intending to discharge treated sewage effluent into the sea on or aſter 1 January 2018. Sewage treatment plants installed prior


to 1 January 2016 and on or aſter 1 January 2010, on ships other than passenger ships operating in MARPOL Annex IV special areas and intending to discharge treated sewage effluent into the sea,


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should comply with the earlier resolution MEPC.159 (55). Sewage treatment plants installed prior to 1 January 2010 on ships other than passenger ships operating in MARPOL Annex IV special areas and intending to discharge treated sewage effluent into the sea, should comply with resolution MEPC.2 (VI). In order to meet the required standards


vessel owners and operators will need to use an approved waste water treatment plant to process grey water, that is water from showers and galleys and black water which comes from toilets and may contain faecal matter. However, the IMO stipulates that:


“an approved sewage treatment plant should not rely solely on the dilution of wastewater.” Treatment of effluent should meet


the standards required by the IMO, that is, “The geometric mean of the thermotolerant coliform count of the samples of effluent taken during the test period should not exceed 100 thermotolerant coliforms/100ml as


ome confusion over the implementation of the regulation MEPC 227(64), which governs


ACO Marine MD Mark Beavis says: “Lots of technologies use dilution, but dilution is not a solution to pollution; it is not treating it, it is reshaping it; we can treat it and remove the pollutants”


determined by membrane filter, multiple tube fermentation or an equivalent analytical procedure.” In addition, the Total Suspended Solids


(TSS) content of the samples of effluent taken during the test period should not exceed 35 Qi/Qe mg/l, where Qi is influent and Qe is effluent. Meanwhile the IMO stipulates that


the method of testing should be through filtration of a representative sample through a 0.45μm filter, followed by drying at 105°C and weighing. An alternative would be the centrifuging of a representative sample (for at least five minutes with mean acceleration of 2,800-3,200g), drying at a minimum of 105°C and weighing or any other internationally accepted equivalent test standard. Te IMO advises that: “Administrations


should ensure the sewage treatment plant is designed to reduce both soluble and insoluble organic substances to meet the requirement that the geometric mean of a five-day biochemical oxygen demand


The Naval Architect March 2016


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