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The amended regulation governing ship wastewater discharge overboard requirements,

the MEPC.227(64), came into effect in January with questions still pending over details, such as the addition of the »special areas« requirement, writes Samantha Fisk
The IMO adopted resolution MEPC.227(64) with revised guidelines for effluent standards and performance test procedures for sewage treatment[ds_preview] plants. These guidelines, which supersede resolution MEPC.159(55), include the standards of section 4.2 that specifically apply to passenger ships operating in MARPOL Annex IV »special areas«, which intend to discharge treated sewage effluent in to the sea.

Concern over section 4.2 of the regulation that specifically highlights special areas was highlighted by Lloyds Register (LR) late last year saying that: »Entry in to force of MARPOL Annex IV requirements prohibiting passenger vessels from discharging sewage within the Baltic Sea area. These requirements were intended to apply to new passenger ships from January 2016. However, a delay in arranging and/or confirming reception facilities in the nine Baltic Sea states means that the special area cannot take effect on this date. Therefore, the IMO’s MEPC has agreed in principle (i.e.: without formally amending MARPOL Annex IV yet) to implement the requirements from 1 June 2019 (and 1 June 2021, for existing ships).«

At the IMO MEPC 69 meeting in May the guidelines concerning the dates that the regulation would come in to effect for the special areas was amended and now states that: »In the special area, the discharge of sewage from passenger ships will generally be prohibited unless the ship has in operation an approved sewage treatment plant that meets the applicable additional effluent standards for nitrogen and phosphorus in accordance with the 2012 Guidelines on implementation of effluent standards and performance tests for sewage treatment plants (resolution MEPC.227(64)). The dates are: for new passenger ships, on 1 June 2019; for existing passenger ships other than those specified below, on 1 June 2021; and for existing passenger ships en route directly to or from a port located outside the special area and to or from a port located east of longitude 28 10’ E within the special area that do not make any other port calls within the special area, on 1 June 2023.«

The aim of the updated regulation, including the special area, clause, has the specific aim of reducing nitrogen and phosphorous from treated water. To counteract this problem the IMO has introduced the Dilution Compensation Factor into the MEPC.227(64) regulation, to address technologies that use dilution in systems.

One of the concerns that the amendment has raised is that many systems will not be able to meet with the requirements, meaning owners will be left with no option but to retrofit new systems.

Mark Beavis, managing director, ACO Marine explains that: »A Biological system that passed the previous MEPC 159(55) regulation should pass updated regulation. Others that use other technologies need to rethink their systems, looking at the sludge and how it is handled.« Beavis further highlights that although ACO Marine doesn’t offer a solution for the large cruise ships, it is expected that these types of vessels that will be mostly affected by the change to the regulation.

The annual Friends of the Earth (FOE) survey, published in June, documented the environmental footprint of 17 cruise lines and 171 cruise ships finding that a significant proportion of vessels continue to operate out-dated sewage treatment plants. The FOE found that 40% of cruise ships continue to use 35-year old technology, calling for an urgent upgrade to systems capable of preventing environmental damage from the discharge of poorly treated, black, grey and galley wastewater streams. »The FOE report paints a contrasting picture of the environmentally conscientious one offered by the cruise lines themselves,« says Beavis. »That 40% of cruise ships are still using wastewater treatment technology developed in the 1980s suggests that some of these cruise ships are unable to meet current regulatory requirements. Certainly some of these vessels will be incapable of meeting the more stringent requirements set out in MEPC.227(64), which limits the amount of phosphorous and nitrogen discharged in treated effluent.«

The new amendments to the MEPC regulation has prompted equipment manufacturers to further develop their systems in some instances to meet with the new standards. ACO Marine is one of the companies that has invested in research and development of its water treatment technologies in order to meet with the MEPC.227(64), including the section 4.2 for vessels with 12 passengers or more. The ACO Marine Maripur NF and Clarimar MF utilise membrane bioreactor technology that incorporates ACO Marine’s »Bio Sword« filtration system, which has allowed to reduce the system’s footprint and operational costs considerably, the company claims.

According to the company, the »Bio-Sword« allows operation with biomass concentrations in the activation chamber of up to four times higher than those of a conventional settling type sewage treatment plants. However, Dr Wei Chen, future program development manager, Wärtsilä water systems questions the effectiveness of the updated regulation: »When equipment is installed the amount of dilution water used during operation may not be visible, hence operators and inspectors may not know if the approved dilution compensation factor is adhered to.«

MARPOL Annex IV has a serious lack of enforcement regime since its birth, this is the root-cause of wide spread poor treatment performance on ships that set to continue into the Special Area. The Netherlands has raised the alarm at MEPC meetings, twice, but in vain. »The situation is now getting worse, in addition to a weak regulatory framework and poor treatment performance on board, designs that do not conform to the requirements of the MEPC resolutions are now being introduced to the ships, especially on new build merchant ships, some approved by the Recognised Organisations by mistake,« adds Chen.

Dr Chen opines that vendors have the technical knowledge and expertise, »and we share the responsibility of helping our customers to avoid deficiencies and non-conformities, but not the opposite«. Technology around monitoring sensors has been under development for this application. Gill Sensors & Controls design and manufacturer sensors for harsh environments and is currently developing a sensor for blackwater that it expects to launch in January 2017. Measurement of blackwater tanks onboard vessels has proved an extremely difficult application due to substance build-up causing sensors to break or report inaccurate readings. The GS level blackwater liquid level sensor currently in development will be built to provide users with reliable measurement that is resistive to substance accumulation, the company says.
Samantha Fisk