VESSEL REVIEW | Catchy 2 – Litter collector prototype to undergo trials in European rivers

Switzerland-based Allseas has developed a new means of collecting litter from some of Europe's rivers.

The Catchy 2 prototype riverine litter collecting system has been installed underneath the Erasmus Bridge in Rotterdam in the Netherlands, where it will remain for approximately one year. The system will collect both floating and submerged rubbish from the Nieuwe Maas River before it could flow out into the North Sea.

The system comprises three key components: two floating booms, a collection cage, and a floating frame. The booms guide waste floating on and below the surface into the collection cage. The collection cage is held in place by the floating frame. When full, the cage is emptied and the waste is recycled. Collected plastic is used for the production of concrete blocks for quay protection.

The vessel works entirely on tide and current, while its robust design ensures its operation is not limited by weather conditions.

The system is an improved variant of Allseas' earlier Catchy litter collector, which has been in operation for several years. The design parameters of the first system are used for the basics of Catchy 2. However, the developer wanted to explore other prospects such as possible scale-up of the system.

Allseas said the most important differences are technological. The new system is to be deployed beneath the Erasmus Bridge in Rotterdam, in the river Nieuwe Maas, which means that it must cope with a greater number of different variables compared to the first-generation Catchy. The biggest difference is the continuous flow of a large river, in this case near a coastal area.

Catchy 2 is designed to be able to remove plastic from the river both in ebb and in flood conditions with varying direction of flow. This is enabled by the non-return door systems, which have been adjusted to the flow.

Another noticeable difference is the use of floaters instead of spud-piles to allow adjustable mooring. These floaters provide the necessary structural stability while simultaneously improving the ability of the litter collector itself to adapt to different situations.