One of the key challenges in Delta Technology is related to possibilitiesof 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 cost-effective material for flood defences and as the basis for nature-basedland 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.

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 and/or 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 iscrucial 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.

1) Further characterization of the effect of Tubifex worms in enhancingdewatering of soft sediments via consolidation tests for operationalconcentrations. 2) Exploration of cost efficient feeding strategies to maximize theimpact of worms in the sediment deposits. 3) Exploration of geochemical effects of the worms (e.g. possiblecementation effects). 4) Application of the findings of 2) and 3) in a final characterization ofthe effect of Tubifex worms via consolidation tests.

The dewatering and strengthening of soft sediments are characterizedby the very large waiting periods resulting in the inefficiency andelevated cost of this type of interventions ultimately constituting ashow stopper for an otherwise very attractive solution (e.g. mud iswidely available and thus an attractive construction material). Thistechnique offers a both very attractive cost wise and very efficientsolution. Moreover it makes use of a widely available very efficient andvery resistant meio-invertebrate Tubifex constituting a green butefficient way of addressing the issue. Tubifex happens to be an endemicspecies in both Canada and The Netherlands.This project will begin from the promising results of Phase I (fundedinternally by University of Alberta and Deltares). These will be expandedby exploring the performance of the technique under in-situ conditionswhile also exploring ways to optimize the role of the Tubifex worms andwhile discovering the geochemical consequences for the deposits too(which could offer further possibilities).

Alle partijen krijgen alle resultaten van het Project ter beschikking. De resultaten van de samenwerking kunnen breed verspreid worden. Partijen kunnen over deze resultaten vrijelijk publiceren. De resultaten zullen volledig openbaar beschikbaar zijn, met uitzondering van ter beschikking gestelde achtergrondkennis.

De informatie over dit project wordt kenbaar gemaakt via de website van de TKI Deltatechnologie (projectbeschrijving) en de projectwiki van Deltares (projectvoortgang en resultaten).

Na de datum waarop deze Overeenkomst in werking is getreden, maar uiterlijk tot een jaar voor de beoogde datum waarop het Project zal zijn voltooid, kunnen ondernemers en/of onderzoeksinstellingen, die op het terrein van het relevante subsidieprogramma van het TKI werkzaam zijn alsnog als Partij toetreden. Een later toetredende Partij zal een nader overeen te komen bijdrage in kind en/of in cash moeten leveren die in redelijke verhouding staat tot zijn relatief aandeel in het Project na toetreding. De overige Partijen ontvangen vervolgens naar rato een terugbetaling en/ of gedeeltelijke vrijstellingen van hun nog te leveren bijdrage in kind, voor zover niet besloten wordt de bijdrage van de later toetredende Partij aan het projectbudget toe te voegen.