17. In a closed system there is a high production of quality fish on a relatively small area. In a closed system, there is independent of the location; all year round a constant production of high quality fish while farming in a closed system is independent of climate and environment.
18. It is always summer in a closed recirculation fish farming system.
28. Looking at the costs for such an extra filtration unit and the increasing production costs we usually will accept new water intakes up to 300 litre per kilogram feed. Compared to a “controlled” open system, we can save on heating or cooling costs by constant mechanical and biological filtration and by re-circulating the water.
29. Re-circulating aquaculture systems are the solution for fish production on all locations in all countries. In for example Chile; the control on the health of the fish in the pre-growing phase in open waters has led to major problems. In a re-circulation system it’s easier and better to produce salmon fingerlings and salmon smolts than in the lakes.
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32. In dry countries like Africa or Australia and several Mediterranean countries water is a major problem while there is a lack of rain and evaporation of water in ponds and lakes is enormous. To establish new flow through systems in these countries is not acceptable for economical reasons, financial reasons and environmental reasons. Water uses for farming are often not allowed and water costs are too high.
41. So no disadvantages at all? It’s hard to find disadvantages in a closed re-circulating fish farm but we have a few attention points. Despite we are able to farm several interesting species on a constant optimum temperature without environmental problems, we believe there is a need for “real specialists” in this technology.
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43. Procedure to set-up a fish farm Enough willingness to give up a secured life for an less sure future. The job of fish farmer is interesting and the profits are usually good but working with life stock can be also a risk. Enough financial backing by own capital and/or bank, eventual subsidies must be an extra, never the foundation of a business.
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45. Take care of reliable supply for eggs, fry or fingerlings. Contact feed suppliers and demand assistance on feed regimes. Take care of regular Oxygen supply. Make contacts and eventual contracts for the sales. Find a good supplier of a fish farming system or fish farming elements.
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47. To get licences and grants? Start with your own local government and make them part of your plan. Hopefully they get excited about your plan and see the advantage to have a fish farm in their community. New employment is often a main issue. Follow all the procedures despite they often take a lot of time, but if you can full fill all the demands of the law you will get the licences.
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49. Guaranty to get eggs, fry or fingerlings and guaranty to sell fish For many species there are eggs or fry or fingerlings all year round available. Packing and shipping in a sophisticated way to places all over the world. If you produce a good quality fish on regular base in an area where there is a market or even better a niche market there is no problem to sell your fish.
55. Start a farm by buying eggs, fry or fingerlings or buy an average stock To start from zero or buy a stock often depends on the capital men can spend. When there is financially no objection: Start with eggs, fry or fingerlings especially when you selected a fast growing fish. Anyway; always go for “new fish”; You never know what you get when you buy bigger older fish.
56. Keep your farm free of diseases or at least keep the risks as low as possible Buy eggs, fry or fingerlings from good reliable suppliers. Use normal protection rules that people can follow and are willing to follow. Too many protections with foot baths, booths, shoe covers, hand cleanings, jackets, caps et cetera are often overdone.
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58. Differences between designs with different species and in fresh water or salt water Besides the right material choices, there are no major differences. There is a basic design for a Hesy system with some loops for better water treatment and for waste water treatment. It often depends on the species and on availability of the right and enough water.
63. HESY system with trickling filter Fish basins Trickling filter Oxygen Submerged filter Protein skimmer Ultra Violet unit De-phosphation Sludge Oxygenator Heater Heat exchanger Ventilator Pump Fuel Pump Pump De-nitrification Heat exchanger Intake water Wastewater Storage Pump Rinse pump Sump below filter Sump below filter Wastewater Drum filter Drain Heater Fuel
64. HESY system with moving bed filter Fish basins Aerator O2 supply Up flow filter Ultra Violet unit Oxygen reactor Pump Pump Heat exchanger Waste water Storage 19 Rinse pump Moving bed filter Pump sump Drum filter Cleaned Waste water Sludge 10% dry Central heating Intake water Heat exchanger In pump sump 20 De-phosphate Pump Protein skimmer Belt filter Oxygen reactor Pump De-nitrification
70. Water consumption and waste discharges. (Discharge equivalents). This is an example of a waste water test in a 300 tonnes fish farm at full production: Process water 50.000 m3 per annum. C.O.D. 46 mg/l KJ-N 9 mg/l Waste Emission 79,7 (Inhabitant eq).
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72. Grams Nitrogen Ammonia N-NH3 per kg 1.0 Grams Nitrogen-organics per kg 3.5 Grams Phosphorus P2O5 per kg 5.8 Grams Kali K2O per kg 0.4 Grams Magnesium MgO per kg < 0.7 Grams Natrium Na2O per kg 0.9 A test in a farm before and after the installation of a de-nitrificate and de-phosphate unit: Before filtration After filtration C.O.D. 1.400 mg/l 67 mg/l S.S. 752 mg/l 63 mg/l B.O.D. 320 mg/l 17 mg/l Phosphate 45 mg/l 0,4 mg/l
73. Less water consumption when we use de-nitrification and de-phosphation Quantity of new water and waste water can be less, as we accomplished in a practical situation in a standard system. With de-nitrification and de-phosphation we can count with less than 30% of the normally used 250 litre per kilogram feed.
77. Energy consumption in a fish farm In a system with all loops - for example a pike perch farm or an eel farm - without energy to produce oxygen it we need ± 7 kW electrical energy per kilogram produced fish. For Oxygen supplied by a generator we calculate ± 0.7 kW per kg production. Average we calculate with 0.7 kg O2 per kilogram production.
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