Facility and equipment
The size of the production tanks in a raceway-style is 35 x 5m with a height of 75cm. The water level is adjusted at about 50cm. The resulting water volume per tank is about 80 cbm. The farm operates with four tanks. Two tanks are in the floor, two tanks above in the first storey (see picture). Each two tanks are connected to its own water recirculation unit (RAS). The tanks are constructed in two different ways. Two tanks are made with a special high density concrete (Ultralith / Nanodur) which does not need any metal framework; two other tanks are built with special Polyethylene boards in black. Apart from regular production, the shrimp farm in Grevesmühlen is being considered as a demonstration facility, thus the application of the two different tank constructions.
The farm is using artificial sea water which is based on fresh water from a well. In the adaptation tanks for the larvae, the salinity is initially adjusted of the origin of the larval stages from a farm in Florida with about 36 psu. The salinity in the production tanks is 15psu. In an adaptation period, the salinity in the larval tanks is decreased by 1psu/hour. The water temperature is kept around 30°C in the production tanks. The air temperature in the facility is about 31°C. This setting avoids significant evaporation of water from the tanks. Thus, air humidity is kept closed to 70%. The water filtration systems of the farm (RAS) operate continuously, keeping the water clean and providing a healthy environment for the shrimp. These recirculating systems work in several steps including solids removal, biofiltration, CO2 removal, denitrification, protein skimmer with ozonisation , UV-disinfection and oxygenation. The removed sludge is discharged to the close sewage plant. The operation of the farm based on RAS technique has the advantage that the water quality can be precisely controlled and significantly reduces the amount of water and space required. The water supply rate is about 3-5% per day. The introduction of the water into the tanks is managed by several inlets in order to ensure an equal water quality in the entire tank. The water exchange rate in the production tanks is 0.5 to 1 per hour.
The facility has a heat demand of 70 kWh. The annual demand for heating energy is supposed to be 600 MW which is provided from a biogas facility for a reasonable rate.
The facility has its own laboratory, equipped with all necessary means to monitor water quality and production parameter in general.