Aquaponics system:A solution to limit nutrient release

from fish farming ?

Christophe Jaeger, Pierre Foucard, Aurélien Tocqueville, Sarah Nahon, Joël Aubin

220th Nitrogen Workshop, Rennes

Recirculating Aquaculture System (RAS)

Hydroponic System

320th Nitrogen Workshop, Rennes

Context

Multi goals for aquaculture :

• Aquaculture products more and more required

• Produce in systems environmentally friendly

• Sustainable systems and less dependent in exogenous resources

Is aquaponics system a solution ?

420th Nitrogen Workshop, Rennes

Aquaponics system studied

UV filter

Permeablegeotextilebag for sediment

Rotary drum filter

leachate

Moving bedbiofilm reactor(8 m3)

+ oxygenation Inlet water

200 l /kg feed/day

3.7 m3

4 Raft bedsarea: 4,8m²/raft bedwater volume: 550 l

3.7 m3 3.7 m3 3.7 m3

Wastewater

Settlingtank

Common tank

Flow rate of 45m3/h

Fish tanks with common carp

520th Nitrogen Workshop, Rennes

• A nutrient budget calculation approach carried out on 52 days

• Concentrations determined for N and P by analyses from different samples, except for fish from literature

• Measurements of inputs and outputs for each compartment of the system (quantities, volumes)

Material and methods

620th Nitrogen Workshop, Rennes

Sampling and analyses

3.7 m3

feed delivered

3.7 m3 3.7 m3 3.7 m3

Fish

Lettuce seedlings

Inlet water

Circulating water

INPUTS

720th Nitrogen Workshop, Rennes

Sampling and analyses

3.7 m3 3.7 m3 3.7 m3 3.7 m3

Fish

Lettuce

Outlet water

Circulating water

Sediment

OUTPUTS

leachate

820th Nitrogen Workshop, Rennes

ResultsNitrogen Budget

values expressed in percentage of total inputs

INPUTS OUTPUTS

Fish biomassproduced

18.7%

Lettuce biomassproduced

0.6%

920th Nitrogen Workshop, Rennes

ResultsINPUTS OUTPUTSPhosphorus Budget

values expressed in percentage of total inputsFish biomass

produced19.9%

Lettuce biomassproduced

0.7%

1020th Nitrogen Workshop, Rennes

Conclusion

• N and P removed from circulated water but in poor proportions

• Interesting system but needs to be improved to be really efficient

increase crop area to improve retention rate : potential of833 m² (N) and 585 m² (P) P is the limiting element

Need to take also into account micronutrients (Fe, Ca, Mg …)

• Unaccounted N : probably mostly explain by denitrification

Aquaponics system is a way to explore but not yet the solution

Thank you