ACO Marine has concluded the commissioning of wastewater treatment units aboard the roll-on/roll-off passenger (Ropax) sisters Sveti Krsevan, Supertar and Cres, operated by Croatian shipping firm Jadrolinija.

According to the contract, ACO Marine retrofitted the three 87.6m ships with a Clarimar MF-2 biological type sewage treatment plant.

Equipment for all three retrofits was supplied between December last year and January 2019. The retrofitting was carried out at the Dalmont shipyard in Kraljevica, Croatia.

ACO Marine’s Italy-based engineering partner La Fornitrice concluded the commissioning of the system aboard Cres, which is the third and final ship in the series.

According to ACO Marine, the contract involved the delivery of the detailed installation drawings to the shipyard and securing the approval certificates from the Croatian Ship Register (HRB).

Before the installation and commissioning of the Clarimar units, the ships were not treating wastewater streams. Instead, they were collecting effluent in holding tanks that required emptying on a daily basis during the summer season.

ACO Marine managing director Mark Beavis said: “The storage of a vessel’s wastewater streams in onboard holding tanks is not the most operationally efficient solution. The use of port reception facilities can be costly and also delay ship turnaround times.”

Jadrolinija was required to install wastewater treatment units after Croatia mandated that ships must be fitted with systems for treating and monitoring wastewater discharges.

Jadrolinija is also planning to install the wastewater treatment units at the remaining five vessels of the same class, which are Hrvat, Juraj Dalmatinac, Marjan, Jadran, and Biokovo.

The ferries will be fitted out with the larger Clarimar MF-3 units, which La Fornitrice will start delivering from mid-October.

Beavis added: “We anticipate a run of orders from Croatia-based ship operators, as they look to retrofit wastewater treatment systems to meet the new requirements.

“ACO technology was accepted by the owner as suitable to upgrade their wastewater handling arrangements. Purchase was made through public tender, choosing the Clarimar MF-2 system through La Fornitrice as best bid price.

“The successful installation and performance of these units resulted in July in La Fornitrice winning another national tender for the retrofitting of the Clarimar system to an additional five ferries in the Jadrolinija fleet.”