The benchmark in silt Amoras
Joury van Gijseghem
DEME Blue Energy
Port authorities looking to making the switch to sustainable silt dredging and treatment technology can’t look past AMORAS, the Antwerp super project that is now four years into its 15-year exploitation phase.
DEME Design and Construction Manager Joury van Gijseghem led the successful completion of the AMORAS project’s initial phase in 2011. SeReAnt, a joint venture of DEME, Jan De Nul and their respective subsidiaries DEME Environmental Contractors and Envisan, had just 30 months to design, build and commission arguably the largest silt dredging and treatment project in the world, representing a construction investment of EUR 118 million.
After AMORAS, Mr Van Gijseghem moved on to a new role as General Manager of DEME Blue Energy, but he recalls with precision the challenges then in front of him.
Huge project, short timeframe
The project scope was complex with several large treatment plants, settling basins and several kilometres of transport pipelines. Plus, the project required two separate dredge installations, as Mr Van Gijseghem explains from his office at the DEME Group headquarters near Antwerp.
“It was a combination of the dredger and, on the other side of the site, two pumps for the dredging gantry over the settling basins. We needed very reliable equipment to operate with minimum downtime over a long 15-year period. The response from Damen to our call for tender, plus the first discussions that took place – that went very well and we had the idea that it was going to work with Damen. In the detailed engineering we worked very closely together – it was a very close and fast collaboration. It had to be fast, because we were under time pressure. In the end, Damen delivered the custom-designed equipment within 14 months.”
Sustainable public works
The AMORAS project, initiated by the Flemish Government and the Port of Antwerp, treats dredged spoil and stores up to 500,000 tonnes of dewatered silt and sludge each year in a new and sustainable manner. The process limits the environmental and ecological risks compared to alternatives, such as dumping on quays or lagooning. It reduces the space required for disposal and protects the port area from sea, air and groundwater pollution.
As Mr Van Gijseghem confirms, the super project is performing well and the uptime of the dredger has been a critical factor. If the dredging spoil is not pumped ashore in time, the whole project stands still.
“AMORAS has been going strong for several years now and the dredging equipment has been extremely reliable. There’s condition monitoring of the dredger as well, to make sure we can plan maintenance, with parameters for preventative and predictive scheduling.”
Unique benchmark project
The 30-hectare AMORAS storage site has capacity for filter cakes of dewatered silt up to a height of 50 metres, providing an operational lifespan of at least 30 years. Meanwhile, research into circular economy applications for the uncontaminated filter cakes is ongoing, such as for clay granules, bricks or road construction.
In the four years since operations began, this unique project has received widespread attention from around the world, proving a successful solution for not just lack of space but also for a more sustainable future.
“It was quite a big project. I think it’s the biggest, or one of the biggest, mechanical dewatering facilities at any port in the world. There are a lot of places with such challenges, Hamburg for example, so many ports have been interested in how we managed to solve it here.”
Rotating Gantry with integrated DOP submersible dredge pumps
- Movable span of approx. 180 metres
- 2 x controllable trolleys with attached Damen ladder
- 2 x identical and interchangeable 150 kW hydraulically driven standard Damen DOP dredge pumps, type DOP2320
- Dredging pump capacity of 1,000 m³/h per pump
- DOP pumps are movable over the radius axis and the working angle can be adjusted by means of a hydraulic cylinder
- Maximum dredging depth of -6 metres
- Hydraulically driven auger head to maximise the mixture concentration
Damen custom-engineered stationary Cutter Suction Dredger type ECSD450
- Capacity of 3,000 m3/h of mixture, for both the cutter action as well as the barge unloader
- Dredging depth of max -18 metres
- Dimensions 34 metres by 9.5 metres
- 2 x inboard Damen dredge pumps – Type BP45 1100 – electrically driven
- 450 mm diameter discharge, 300-metre line connecting to the sand separation plant
- Powered by high voltage shore cable supplying total power on board of 15.75 kV at 1,800 kVA
- Heavy duty cutter ladder swings by means of hydraulic cylinders instead of anchor and side wire winches
- 4 x spuds and 2 x hydraulically operated spud carriages
- The silt travels 4 kilometres in the discharge pipeline to the dewatering plant’s settling pools (120,000 m³ each), a buffer zone to separate silt from transport water.