DEL071 – 1230587 Optimizing the usage of Tubifex to enhance densification and strength of Oil Sands

Aanleiding van het project

Sediment waste of mine processes (tailings) as well as dredged
sediments are stored in dedicated deposits, or beneficially re-utilized to
build new lands (e.g. Marker Wadden), to improve resilience of flood
defences or enhance habitat restoration. However these sediment andor
waste is characterized by a very high fines content, and the
accompanied very long consolidation times (e.g. the soil is very fluffy
and not suitable for construction, and it takes a lot of time for the soil to
gain strength). This results in inefficiencies of the reclamation process,
deriving in very high operational costs.
The ability to speed up the consolidation time of these deposits is
crucial for the future of reclamation of mining areas and reclamation
and flood protection projects with dredged sediment. The techniques
being currently used by the industry are very high in costs and not very
efficient in increasing the soil strength within a competitive time scale,
and thus there is room for improvement and for seeking new
competitive and efficient technologies. This project builds up on the
positive development and findings of the previous phase, towards
further improving consolidation of soft sediments in depositional
processes at reclamation projects.

Doel van het project

One of the key challenges in Delta Technology is related to possibilities
of building on and with soft material. Soft materials (e.g. from dredged
material and mine tailings) can be reused to form robust water
defences, enclosure dams and for land building. The material can be
used to combat settlement in Sustainable Delta Cities, as a costeffective
material for flood defences, and as the basis for nature-based
land reclamations like Marker Wadden. As such, “Bouwen met Slib” has
been identified as an important innovation to strengthen the
international position of Dutch engineering companies.
This project further explores the innovative use of Tubifex worms to
enhance dewatering of sediment at disposal site deposits.

Omschrijving van de activiteiten

1) Further characterization of the effect of Tubifex worms in enhancing
dewatering of soft sediments via consolidation tests, for operational
concentrations.
2) Exploration of cost efficient feeding strategies to maximize the
impact of worms in the sediment deposits.
3) Exploration of geochemical effects of the worms (e.g. possible
cementation effects).
4) Application of the findings of 2) and 3) in a final characterization of
the effect of Tubifex worms via consolidation tests.

Verwachte resultaten

This project will extend the characterization of the beneficial effects of
Tubifex worms in accelerating soft sediment deposits consolidation for
operational and in-situ conditions, explore the impact of cheap feeding
strategies in the former, investigate geochemical consequences of the
technique for the deposits, and overall contribute to the design of a
strategy to apply this technique in-situ that can be cost efficient and
attractive to the industry. One (or several) scientific publications will be produced too.
Alongside the produced knowledge, the results of the project will
provide an improved understanding of mine tailings and dredged
sediment management and reuse. Through partners such as IOSI,
University of Alberta and Imperial, this will lead to an enhancement of
international knowledge within the industry network.
This knowledge will be able to be utilized by the Dutch partners (e.g.
dredging industry or RWS) on large on-going soft sediment projects to
improve accuracy of design and reduce risks and cost (e.g.
MarkerWadden), as well as in the support they bring to the
management of waste from mining worldwide.

Innovativiteit

The dewatering and strengthening of soft sediments are characterized
by the very large waiting periods, resulting in the inefficiency and
elevated cost of this type of interventions, ultimately constituting a
show stopper for an otherwise very attractive solution (e.g. mud is
widely available and thus an attractive construction material). This
technique offers a both very attractive cost wise and very efficient
solution. Moreover, it makes use of a widely available very efficient and
very resistant meio-invertebrate, Tubifex, constituting a green but
efficient way of addressing the issue. Tubifex happens to be an endemic
species in both Canada and The Netherlands.
This project will begin from the promising results of Phase I (funded
internally by University of Alberta and Deltares). These will be expanded
by exploring the performance of the technique under in-situ conditions,
while also exploring ways to optimize the role of the Tubifex worms and
while discovering the geochemical consequences for the deposits too
(which could offer further possibilities).

Valorisatie

This project will take advantage of parallel collaboration with University
of Alberta (U of A) and Imperial. U of A will provide insight on
geotechnical processes and background knowledge to the field (e.g.
long and fruitful collaboration between U of A and the industry). On the
other hand, Imperial will provide testing materials and knowledge about
the operational conditions.
The theory developed will be disseminated by Deltares at short courses.
Project results will be presented at various conferences worldwide (e.g.
IOSTC;OSTRF;etc)

Link naar projectresultaten…