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- In Phase 1 of this research a stable gel that can be used for making gel barriers was designed by a PDEng student of the TU Delft (Bampatzeliou , et al., 2022);
- Phase 2 focusses on the ability of a gel barrier to reduce sedimentation and its interaction with navigation and flow conditions in the Port of Rotterdam (Deltares Jaksic and de Wit 2022).
Gel barriers are intended as biodegradable obstacles which could be placed on the bottom of a port entrance to reduce the spreading of sediments into certain port areas (Figure 1). Gel barriers are a combination of dredged material (i.e., excess sediment) and a biological flocculating agent, which should result in a stable yet eco-friendly barrier. Several types of flocculants will be tested. One of the potential candidates is Kaumera Nereda® Gum, which is a new bio-based raw material that is extracted from the sludge granules that form during the Nereda® purification process.
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Bampatzeliou et al. (2022) tested different gelation agents and found that the gel stiffness of the final product can be tuned by adjusting the concentration of solids and gelation agent in the final recipe. Gels with shear stress from 80-5,000 Pa can possibly be developed by mixing mud from port of Rotterdam with a gelation ingredient. Kaumera with the current low concentration of solids does not provide sufficient strength to build a barrier. A more appropriate application would be as an eco-friendly flocculent as it is seen that dried Kaumera can increase flocculation rates in diluted clay suspensions. Xanthan Gum, a polysaccharide polymer, has promising properties for the application of a gel barrier in terms production costs/effort, stability and durability. Xanthan Gum (XG) is readily used on large scale in the food industry and even in dyke projects as a stabilization agent for soil. By mixing local mud from the port with small quantities of XG (0-3% mass) a wide range of Bingham Yield Strengths can be realized (0-400 Pa) by varying the solids and/or XG content. Three gel examples with XG are summarized in the table below.
Name | Bingham Yield Strength (BYS) [Pa] | Bulk density [kg/m3] |
XG3Mud20 | 400 | +/- 1200 |
XG1Mud10_v1 | 200 | +/- 1100 |
XG1Mud10_v2 | 100 | +/- 1100 |
A 100 Pa gel represents a gel that would not obstruct navigation if a vessel would sail into the barrier. Based on experiments in several ports around the world, it was found that fluid mud layers with densities up to 1200 kg/m3 remain navigable. Furthermore, the German port of Emden prescribes that fluid mud is navigable up till 100 Pa (Kirichek, et al., 2018). XG1Mud10_v2 has properties within these limits (Table 2‑1). The 400 Pa gel (XG3Mud20) represents a material that could be used in locations where more strength is required, and where the draught of vessels is not limited. Bampatzeliou et al., (2022) showed that the gel’s strength is time-dependent and some swelling and weakening over time can be expected, although this influence will be stronger in lab-scale as in field-scale.
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It is logical and a relatively limited effort to start with line 1. When line 1 is finished lines 2 and 3 could be done simultaneously as there are interactions between them. When lines 1-3 are completed then it is recommended to start line 4 which is a small-scale pilot field test to learn in practice.
Our products are:
- Phase 1: Bampatzeliou, A., Daudey, P., Chassagne, C., Kirichek , A., de Wit, L., van Leeuwen, Y., Renard, V. (2022). Design of a Gel Product for sedimentation control in the Rotterdam port area. Delft.
- Report of Phase 2 can be found herePhase 2: Jaksic, L. and de Wit L. (2022), Gel barriers in the Port of Rotterdam, Analysis of the hydrodynamics, sediment transport and stability, Deltares report 11207279-000-ZKS-0001, 15 November 2022, download.