Ammonia Removal for Recirculating Aqua Culture System (RAS) at Dabie Hatchery, Poland
DabieHatchery , Poland is the largest Salmon hatchery in the Eastern Europe supplying quality salmon eggs to entire Eastern European region. The hatchery run by highly experienced and renown experts in the field, has large production facilities comprising RAS system for the treatment of the recycled water to remove excess ammonia and other by products which otherwise are harmful to the fish eggs.
Due to their penchant towards improving the Salmon egg quality and improving the finished product quality, Dabie had been looking for an optimal carrier for their RAS system which removes various nitrogen species from the recycled water to much finer levels.
Normally, Ammonia > 1 ppm and Nitrite (NO2.N) > 0.5 ppm are extremely toxic to the fish and reduce their quality production due to higher mortality rates and deformities in the grown fish.
THE PILOT TRIALS
In order to assess the removal efficiencies of different carriers and to obtain kinetics parameters for the design, a continuous pilot trials with different carrier material was conducted at the site. A parallel bank of pilot plant was constructed at site which was fed with the recycle water having different carrier material in it.
Fig 1 : different Carrier materials compared at Dabie Hatchery RAS System Pilot Trials
Fig 2 : Biofilter Pilot Plants at Dabie Hatchery
Each pilot with different carrier material was fed with pre treated and pre aerated recycle water which was then analyzed for its Ammonia, Nitrite and Nitrate Nitrogen removal efficiencies on grab samples collected weekly
The results indicated that Levapor carriers based biofilters outperformed conventional PE , PU foam and Ceramics carriers based biofilters for the removal of Ammonia, Nitrite and Nitrate Nitrogen.
Fig 3 : Removal of Ammoniacal Nitrogen with Levapor carriers versus PE carriers.
Fig 4 : Outlet Ammonia levels achieved with different carriers.
Fig 5 : Outlet Nitrite Nitrogen achieved with different carriers.
Fig6 : Total NH4.N +NO2.N removal achieved with different carriers.
The results of the pilot trials indicated that Levapor carriers outperformed conventional plastic carriers by 100% for Ammonia nitrogen removal. Due to higher inner porosity and fine pore structure of Levapor carriers, a significant amount of Simultaneous nitrification and denitrification was achieved reducing the Total nitrogen species at the outlet of the Biofilters supported by Levapor carriers. The test results revealed that for Total Nitrogen (NH4.N+NO2.N) removal , Levapor carriers outperformed conventional PE based carriers to 300% achieving lowest levels of NH4.N and NO2.N due to better nitrification and denitrification.
FULL SCALE IMPLEMENTATION
Dabie Hatchery has initiated replacement of their existing RAS system’s PE carriers with Levapor carriers. The implication of better Ammonia removal and reduction in toxicity with Levapor carriers supported RAS system are quite encouraging. Even an independent review by Hatchery international has noticed that the Fish quality and gill texture and shape of the fish has improved quite a lot after implementing new carriers for the RAS system.
BENEFITS OF LEVAPOR SUPPORTED RAS BIOFILTER AT DABIE HATCHERY ARE
Highest removal of Ammonia and Nitrite Nitrogen
Drastic reduction in the toxicity to fish due to lowest levels of Nitrogen species in the recycle water
Better fish quality due to healthier growth conditions available