Pedersen DTU Aqua

8/13/2019 Pedersen DTU Aqua

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08/06/20

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


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


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)


DTU Aqua


DTU Aqua

Courtesy: P.B. Pedersen


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Modeltroutfarmcomponents sludgecones

DTU Aqua

Courtesy: A. Jokumsen


Modeltrout

farm components

drum

filters

< 75 m mesh

Solids removal +

parasitic control

DTU Aqua

Courtesy: A. Jokumsen


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Modeltroutfarm componentsBiofilter

NH3/NH4+ -NO2

- &

COD reduction

DTU Aqua

400 m2

biofilter

surface

pr. ton

feed/yr


Modeltrout

farm components

airlifts

Airlift: water circulation, O2CO2

DTU Aqua

Alternative: Pumps, O2 and trickling filters


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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


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)


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*


Dischargedamounts(example)


NH3+NH4N 39 25,4


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NewgenerationopenRASsystems[FREA]

DTU Aqua


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

Documents

Pedersen DTU Aqua