INSPIRATIONSDAG FÖR FISKODLING PÅ ÅLAND 27. Feb. 2020

Hav-Tek, danskt utvecklingsprojekt –Developing and test of feed with reduces P-content and possibility to take up sludge/fishfaeces

Lisbeth Jess Plesner, chef Adviser v. Dansk Akvakultur (producers organisation)

Erik Damgaard Christensen, professor v. DTU-Mek, Dks tekniske Universitet.

Funding: GUDP (Grøn Udviklings- og Demonstrations Projekt) 4.127.285 kr. (550.000 Euro)Partners: AquaPri A/S, DTU Aqua, sektion for akvakultur, DTU Mekanik, Biomar, Dansk Akvakultur, Hvalpsund NetPeriode: 01-07-2019 til 31-12-2022

Project Hav-Tek

Development and testing of technical solutions for a more environmental optimized sea cage farming.

Developing and testing P- reduced feed, faeces structure and sinking rates

Modelling and developing equipment for faeces collection (solid faeces).

Fish quality and performance, roe quality, growths rates, fish welfare

Available raw materials/ingredients to commercial feed

Sludge quality / faeces collection, storage and utilization

Price – economically sustainably business case

Kilde. DHI Rapport 2014

Project Hav-TekN and P effluent - primary obstacle to growth in in seacage fish production in the Baltic.

Today N and P effectivity for seacage farming in DK *P: 3,5-5 kg P pr. tons fish producesN: 38-46 kg P pr. tons fish produces

Project -> Reduce outlet P and N pr. produced tons fish.

Status og grundig gennemgang af havbrugsområdet

Kilde: BioMar, Data sheet Commercial fishfeed

* Dalsgaard A. J. T. & Pedersen P. B. (2016): Produktionsbidrag og dambrugsmodel: manual og modelforudsætninger. DTU Aqua-rapport nr. 309-2016.

2020: DTU-Aqua Laboratory test

Resul

Status og grundig gennemgang af havbrugsområdet

April – Dec. 0,8 kg – 4 kg rainbow trout (roe).

1. Control 0,8% P. Commercial feed EFICO Enviro 939Adv 6/8mm, P content 0.8% (0,41% fish need)

2. Test diet 0,65% P. The digestibility of phosphorus in the raw materials is higher, which means that the diet as above contains 0.41% (fish need) available phosphorus.

3. Test diet 0,6% P. The diet is added the enzyme phytase which releases otherwise inaccessible phosphorus from vegetable raw materials. This further increases the phosphorus digestibility of the diet.

DTU Aqua also test faeces sinking rates and structure.

2021: Test in Agersø Havbrug

AquaPri: Agersø Havbrug

Full scale Test in a commercial seacage ( April – Nov/Dec. 2021).

Test diet: Depending on result from lap.

Test: Fish, welfare, quality test

Environmental test/monitoring.

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

Detailed modelling of particle path in fish cage

Erik Damgaard ChristensenDTU-MEK

6

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

An example of a future research driver

Fish cages: An element of a research driver- Forces in mooring systems- Wave structure interaction in open water- Detailed interaction with mussel lines- Spreading processes- Porous media modelling- Extreme wave interaction

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Aquaculture in offshore areas is a focus area under the EC

7 2 March 2020

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

The model development• The model conists of three elements

– A model for the porous net structure (net+ seaweed)

– LES (Large Eddy Simulation) of the flow

– Particle model

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DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

Wave interaction with porous media in the marine environment

ICCE2014

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

Fish cage model development 1/2

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

Fish cage model development 2/2

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

• LES-DEM model (Large Eddy Simulation combined with Discrete Element Method)• LES: Models the flow including large scale vortices• Dem: Particle model.

Flow proporties in a protection layer (1/2)

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

Flow proporties in a protection layer (2/2)

Turbulent quantities for a hydraulically

rough boundary layer from

Vorticity around the

spherical elements

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

Flow penetrationFlow and sediment particles

t = 0.2 s

t = 0.4 s

t = 0.6 s

Movement of particles inside

protection layer

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

• Wave/Seabed/structure interactionHydrodynamics and sediment transport in protection layers

Xerxes Mandviwallas PhD project. Part of MSBWIICCE2012

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

Basic test case with all three elements.

DTU Mechanical Engineering27 February 2020 Åland fiskeopdræt

Controlling the flow to create ”tea-cup” principle