Bolina Ltd, an Ecocoast company, has engineered what is claimed to be the longest river barrier in Europe to catch plastic and other floating debris.
Commenting on the barrier installed on Belgium’s Scheldt River, Gregory Duquennois, Ecocoast project lead said: “Our core purpose is to pioneer and therefore we are proud to have designed a bespoke product that leads the way in waterway protection. We look forward to creating further product solutions across European waterways to assist in cleaning the rivers, so that ecosystems and people can continue to benefit from what can be called the heartlines of Europe.”
DEME installed a litter trap in Temse, with a floating funnel that covers part of the river. Operational 24/7, it catches and collects drifting debris inside the Bolina floating debris barrier. Once the litter trap is full, everything is transferred into a CO2 neutral DEME vessel using VR technology. The debris is then transported to the riverbank, where DEME transfers the litter once again for collection and processing. An innovative design was required due to its tricky location on the Scheldt near the Temse Bridge. Various factors came into play including the tidal effect of up to six metres, the alternating current directions and water speeds of up to two metres per second, as well as the river being a busy shipping route - a fitting challenge for both Ecocoast and DEME.
The original design integrated the tried and tested Bolina floating debris barriers that would rise and fall with the tide. Two giant ‘arms’ would form a funnel and guide the pollution towards the plastic collector to be trapped and then disposed of by means of a waste container and an autonomous vessel. Both arms are constructed from one full length, without intermediate pieces or other connections in order to maintain maximum tensile strength. The arms span 103 metres for the northern side of the funnel and the southern arm is 175 metres.
Due to the extreme tidal effect, Bolina D-500 pile drivers were provided at the beginning of the barriers, which followed the full height difference of six metres, four times a day. At the plastic collector, a special roller system was designed for the connection between the Bolina floating debris barriers and the collector itself. The new roller system allows free movement between the dirt screen and the pontoon in the event of strong waves and tides, without losing any plastic or floating debris.
Waterways worldwide face water pollution challenges, plastic, wet wipes and all kind of debris. Trial and investment from governments, private companies and organisations like DEME and The Flemish Waterway initiative at Temse means these rivers have seen a revitalisation with ecosystems returning and beginning to flourish.