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Recent examples on sustainable
aquaculture development in Denmark
DTU Aqua National Institute of Aquatic Resources, Section for Aquaculture, Hirtshals, DK.
Lars-Flemming Pedersen Bsumer Fischtag, 7/6 2012
BackgroundandstatusinDenmark
Fromflowthroughtorecirculation
ModelTroutFarmconcept
Challenges&Perspectives
http://www.aqua.dtu.dk/English/Research/Aquaculture.aspx
DTU Aqua
Recent examples on sustainable
aquaculture development in Denmark
OUTLINE
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Recirculatingaquaculturesystems
Background&status
0.90
1.00
1.10
1.20
1.30
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
FQR
(feeddelivered/biomassgain)
Annualproduction(MT/yr)
Danish trout production (freshwater)
P ro du ct io n Fee d con su mp tion Fee d q uo ti en t
DTU Aqua
National plan to increase the production > 3x
Source: Danish Aquaculture Organization: Plan for Green Development, 2009
FREA* Model Trout Farm Flow-through
Freshwater trout produc tion prospectives
MT/year
* Fully Recirc. Aquaculture systems
Recirculatingaquaculturesystems
Background
&
status
Recomm. from a national
aquaculture committee in 2002
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Danish trout farms anno 2001(From Faunapassage rapport, 2004)
Danishaquaculturebackground&status
From flow-through to recirculation
Decreasing # of aquaculture facilities
Increasing average production / unit
2009: < 190 traditional fish farms
> 25 model trout farms (RAS)
(> 30% produced in MTF)
DTU Aqua
Model trout farm concepts were
implemented in 2004
Increased focus on sustainability
discharge regulations
EU-Water Frame Directive / EPAEnvironmental neutral production
expansion sustainable development
Flow-through Model Trout Farm Full Recirculation
30 - 60 m3/kg 3 - 4 m3/kg 0,2 0,4 m3/kg
Fromflowthroughtorecirculation
DTU Aqua
Advanced full RAS forhigh value species.
> 70% of all large scale
RAS designed by
Danish companies
Traditional flow-through
rely on water intake fromnatural water courses
Semi-recirc. with
> 95% water reuse.
Environmentally
improved and
economically feasible
relying on RAS
treatment components
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Nitrogenous and Carbonaceous loading is
determined by the by the relative water
consumption (kg feed/m3 make-up water)
Wasteproduct
Dilution (Qin)
Fromflowthroughtorecirculation
DTU Aqua
Fromflowthroughtorecirculation
DTU Aqua
Courtesy: P.B. Pedersen
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Recirculatingaquaculturesystems
Modeltroutfarmcomponents sludgecones
DTU Aqua
Courtesy: A. Jokumsen
Recirculatingaquaculturesystems
Modeltrout
farm components
drum
filters
< 75 m mesh
Solids removal +
parasitic control
DTU Aqua
Courtesy: A. Jokumsen
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Recirculatingaquaculturesystems
Modeltroutfarm componentsBiofilter
NH3/NH4+ -NO2
- &
COD reduction
DTU Aqua
400 m2
biofilter
surface
pr. ton
feed/yr
Recirculatingaquaculturesystems
Modeltrout
farm components
airlifts
Airlift: water circulation, O2CO2
DTU Aqua
Alternative: Pumps, O2 and trickling filters
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Recirculatingaquaculturesystems
Modeltroutfarm components constructedwetlands
DTU Aqua
+ Sludge compartments and geotubes
[organic matter and nitrate removal]
Courtesy: P.B. Pedersen
25 m2 constructed wetland
pr. ton feed/yr
Recirculatingaquaculturesystems
Modeltrout
farms
pros
&
cons
Water course Fish farm
Advantages:
Free water flow up/down stream and
free fauna passage
Reduced nutrient and organic matter losses
per kg produced fish
Reduced discharge of medicines and
therapeutants and reduced maximum
concentrations
Improved oxygen conditions
downstream the fish farm
Reduced losses of fauna from water
courses to the fish farm
Happy entomologists and anglers
Disadvantages:
None
Advantages:
Stable production conditions, incl.
increased water temperature
Improved efficiency of cleaning devices
Improved management control and
production planning
Reduced risk of external infections
Reduced need for medicine/antibiotics
Improved work environment
Disadvantages:
Seasonal fish loss due to parasites
Higher energy consumption per kg fish
Risk of toxic levels of ammonia and NO2- Increased need of supervision and
management
Increased need of back-up systems:
Electricity, oxygen, pumps, etc.
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Removal efficiency in MTF
Parameter Expected Realized
BI5 75% 93%
NH4+
77%
TotalN 31% 50%
TotalP 60% 76%
(After PB. Pedersen & L. Svendsen, 2008)
Recirculatingaquaculturesystems
encouragementand
incitements
to
perform
better
DTU Aqua
Model trout farm has proven successful and economical feasible - and new
concepts have been developed.
Raceways vs. circular tanks improved solids removal, fixed bed vs. moving
bed biofilters and management experiences etc.
Recent legislation allows feed allocation based on effluent values as opposed
to a fixed feed quota. An additional motivation to improve management.
Paramet ers Was tecontribution
(kg/tonsoffishproduced)
Discharged criteria*
(kg/tonsoffishproduced)
Dischargedamounts(example)
(kg/tonsoffishproduced)
NH3+NH4N 39 25,4
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Recirculatingaquaculturesystems
NewgenerationopenRASsystems[FREA]
DTU Aqua
Recirculatingaquaculturesystems
Newgeneration
RAS
systems
[FREA]
DTU Aqua
Design: 1 l/s makeup water
200 tons feed/year
~ 6 kg/m3 make-up water
High N-P-C removal efficiency1.1 kW/kg fish produced
Courtesy: P. Nielsen
Nielsen Consulting, DK.
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Managementissues
Waterquality(microbial&chemical)
Pathogencontrol
TANandnitritelevels(nitrification)
DTU Aqua
ModelTroutFarms
Challenges
Effluent treatment
Reduce Ndischarge
Endofpipe denitrification
Sludgehandling
Perspectives
DTU Aqua
Environmentally neutral production expansion
Effluent based regulation / discharge control
increased focus and motivaiton on effluent composition
MTF and big scale FREA systems (> 2000 MT/y)
Landbased saltwater RAS
Difficult conditions for traditional flow-through fish farms
(Intensification or nich production)
Energy, production and water treatment optimization
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Thanks for the attention