Maritime Technologies
Contact Person: Dipl. Biol. Ralf Fisch, Prof. Dr. Bela H. Buck
Related Projects: AquaInno
Floating Raceway/Recirculation Aquaculture System (FRAS)
A new technology for finfish mariculture will be tested in the project AquaInno. This innovative system combines “In-Pond-Raceways” (IPR) and “Recirculation-Aquaculture-Systems” (RAS) in one ecologically compatible, floating plant. Depending on the operating mode, the system works either as a flow or as a circulation plant. The system has been modified already to in- and near shore deployment. In spring 2007 a prototype will be tested first in freshwater. A second plant follows in summer 2007 for marine use. Together with algae (Laminaria saccharina) cultures devices in the surrounding waters the development of a Floating-Partitioned–Aquaculture-System (FPAS) is intended.
Fig. 2: The pneumatic technique simplifies harvesting procedure. The cultured organisms are concentrated in a small area.
Fig. 1: Freshwater prototype of a floating in pond raceway used for cultivation of ornamental fish in the year 2004.
Further, the hydro dynamic design will be adapted for a potential offshore deployment. This approach will certainly lower the environment impacts of open aquaculture facilities like net cages. The system will be equipped with a multistage filter consisting of a waste collector for separating fish faces and a fixed-film biological reactor metabolizing solved wastes. This will reduce the rate of the intermediate products like ammonia and nitrite and lower the level of TOC, TON, TP and BSB. This could lead to higher stocking densities and improved water quality. The remaining dried waste can be used in biogas plants or as fertilizer for agriculture. The surroundings algae cultures can help to reabsorb the final product nitrate.
Fig.4: In-shore, scientists of the AWI and the company of Müritzfischer compares the FRAS with a net cage system.
Fig.3: A prototyp of the floating recirculating aquaculture system for freshwater application. This system is prepared for cultivation of 1000 kg pike-perch (sander lucioperca) or 2000 kg europaen catfish (silurus glanis).
A closed system is save against pathogens from the aquatic environment and avoids predator attacks from births or seals. The integrated control and sensor system protects the cultured species in case of a surrounding water contamination. Depending on the model deployed the water temperature and quality can be manipulated for the different ecological needs of the cultured candidates. Further, also the surrounding wild populations are protected from escapes, feces, parasites and pathogen loads from the culture system.
Fig. 5: Project AquaInno: Draft of a possible floating near shore system illustrating its components. The water flows from a fishpond (A) to a first waste collector (B), where particles will sediment. A bioreactor (C) eliminates dissolved nitrogen and phosphate. The re-use of water is controlled by sensors (G) and sediment dispose (F) takes place. A pneumatic system simplifies harvesting (E) of cultured organisms. The platform (D) around the pond is improving the overall handling of the device. A surrounding algae cultures (I) eliminates the final product nitrate.
The floating ponds can be connected with each other to create platforms. An integrated pneumatic technique simplifies harvesting and handling of fish. This can help to lower operational costs, make work more efficient and is the premise to install this technique in countries with high wages levels.