The Necessity of Desalination Technology for Designing and Sizing Multi-Loop Aquaponic Systems

Aquaculture Europe 2017, Dubrovnik, Hrvatska

Simon Goddek, Karel Keesman

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Disadvantages:

Suboptimal growth conditions for both plants and fish.

Lower yields compared to stand-alone hydroponic and aquaculture systems.

Fish sludge (faeces) is not used.

One-Loop Systems

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Optimal System Conditions

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Advantages:

Optimal conditions for fish and plant

Remineralization of fish faeces in anaerobic reactors; i.e. creation of bio fertilizers for the plants

Main water loss only via evapotranspiration; i.e. ETc dependency

Increased Yields

Control the concentration of the hydroponic nutrient solution.

Disadvantage:

Measurement and Control

Multi-Loop Aquaponic Systems

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Decoupled Multi-Loop AP System

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Sizing:

Rule of Thumb: 60g feed/m²

Inflow HP = Plant Uptake

Issue: Different Nutrients

Focus: N & P & Nutrient

Concentrations

RAS:

Total Tank Volume: 600m³, Max. Density: 40kg m-³, Fish Species: Nile Tilapia,

Fingerling Weight: 3g, Target Weight: 600g

Hydroponics:

Greenhouse Size: variable (modelled), Plant Species: Tomatoes

Desalination/Distillation:

Operation Flow Rate: 2000L h-1 (during sunshine hours); on/off (modelled)

Remineralization:

Nitrogen Recovery: 40%; Phosphorus Recovery: (optimistic) 90%

MATLAB Simulation – Important Parameters

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Modelling Cases

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2 Cases:

Tórshavn

Almería

60g m-2 when using

fruity plants (e.g.

tomatoes)

30g m-2 when 50% of

the total nutrients is

supplied by

remineralization tech.

Sizing Rule of Thumb

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Almería – Nutrient Balance & RAS Concentration

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Impact on HP-Concentration...

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Faroe Islands vs. Spain #1

Higher radiation =>

Higher Etc =>

Higher N uptake

Nutrient Concentrator – Distillation Technology

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HP sump size dependent

Smaller HP sump: decreased

required flow to achieve

optimal nutrient solution

concentration

However, this also means less

flow of demineralized water to

the RAS.

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Desalination/Distillation technology has the potential to play an

important role in concentrating the hydroponic nutrient solution

Global radiation has a high impact on nutrient uptake and thus

sizing/balancing the system.

Mineralization technology (as presented by Boris Delaide) and its

performance are a key parameter in sizing a decoupled aquaponic

system.

Take home messages

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Thx for attending!

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