Can flocculation reduce the dispersion of deep sea sediment Plumes?

Can flocculation reduce the dispersion of deep sea sediment Plumes?

Ali, W. (TU Delft Environmental Fluid Mechanics)
Enthoven, D.H.B. (Student TU Delft)
Kirichek, Alex (TU Delft Rivers, Ports, Waterways and Dredging Engineering)
Helmons, R.L.J. (TU Delft Offshore and Dredging Engineering; Norwegian University of Science and Technology (NTNU))
Chassagne, C. (TU Delft Environmental Fluid Mechanics)

2022

For green energy transition, the industry seeks alternative resources for nickel and cobalt, the main ingredients for energy storage devices and other applications. Polymetallic nodules lying at the abyssal plain are rich in these mineral resources, which leads to an increased interest in deep-sea mining (DSM) of polymetallic nodules. During the DSM operation, the seabed will be disturbed, resulting in a suspended sediment plume. Such a plume can have a significant environmental impact. As a result, defining the main processes and quantifying sediment plume dispersion is vital for predicting the possible ecological implications. Flocculation could play a key role in minimizing and better prediction of dispersion of turbidity flows generated by deep-sea mining equipment. In this work, we study the effect of flocculation on the propagation of deep-sea sediment plumes by means of conducting a series of lock exchange experiments using artificial deep-sea sediment. Experiments were conducted in fresh and saline water with different clay and synthetic organic matter concentrations. Experiments are conducted in freshwater for comparison with saline water. The head velocity is measured via video analysis. At the end of the lock exchange experiments, subsamples at various run-out lengths are collected for particle size and settling velocity measurements. When experiments are conducted with synthetic organic matter in saline water, the results show that the head velocity reduces significantly compared to freshwater conditions due to the formation of dense flocs.

Sediment plume
flocculation
Deep sea mining

http://resolver.tudelft.nl/uuid:76194b25-760f-443d-bd98-580425b588e0

WODA

2023-07-01

Proceedings of the World Dredging Conference, WODCON XXIII: Dredging is Changing

WODCON XXIII, 2022-05-16 → 2022-05-20, Tivoli Hotel, Copenhagen, Denmark

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

conference paper

© 2022 W. Ali, D.H.B. Enthoven, Alex Kirichek, R.L.J. Helmons, C. Chassagne