Sustainability and respect to the environment are becoming key isses in Aquaculture.
The RAS installation itself is only a half step towards growing fish in an environmental friendly manner.
But very important, the RAS installation makes it possible to concentrate the waste from a fish farm in such a way, that it will be possible to do proper a waste water treatment on the disharge water from the fishfarm.
Even that we within the RAS installation are using the water typically up to 200 times before discharging, we will still pollute the environment, unless we take the necessary actions to clean the water in a separate wastewater treatment plant.
When we at Aqua-Partners decided that it should be Veolia group which should be granted the rights to distribute the RAS2020 technology, we considered it a key element, that no other company in the world has any way near the same experience on waste water handling as the Veolia group.
The principal waste ingredients to be managed from any RAS installation are the following:
Dissolved organic matter /BOD
The outlets from the production in A RAS plant, will contain some amounts of BOD, Nitrogen and Phosphor, but on Phosphor and Nitrogen will even with modest wastewater treatment be less than 50% of the recommended Max outlets from land based marine fish farms in Denmark. And the BOD levels will be less than 2% of the recommended levels per. kg. Produced fish.
Bio variables/waste products in outlets, kilo per ton production of fish:
Recommended max levels
Cage land based Max Outlets from RAS farms
Farming marine fish-farms with waste water handling
BI5 (KG) 220 175 6
NH4-N 29 0,8
Total N 47 44 20
Total P 5,6 4,8 2,4
The outlets form a RAS farm should be secured and disinfected so that no fish can escape from the farm and cause genetic pollution to wild stocks, or cause impact on natural stocks by taking up habitats of natural stocks.
Use of waste products
Sludge form fishfarms is typically used for biogas production.
The compost will be free of medicine residues and low on heavy metals, but will include a variation of micronutrients.
Compost from fish plants can make a very valuable fertilizer and it is anticipated that the sludge management will be cost neutral, that the sale of compost will cover the processing cost and investments to produce the compost.
Guts etc. From slaughtering:
The waste products from slaughtering the fish, can be used to produce a premium quality of fish meal and fish oil.
These waste products, such as gills, liver, guts and heart, which in volume will be equivalent to Approx. 16,5 % of the total biomass produced or 200 ton per year from a single RAS2020 module, producing trout or salmon. These products should be be processed into fish meal and oil.
These products from a RAS farm, will be more fresh than what can be gained from any wild fish caught. A destruction/harnishing of the products will initiate as soon as the fish dies.
The key to produce a perfect quality of fishmeal, is a fresh product, which only can be gained from the slaughtering of live fish, without any partly digested food in the guts..