Aquacria-Piscicolas Turbot Fish Farm

The facility is located in a natural preservation area in the environmentally sensitive region of Torreira in the northern part of Portugal. The property ends at the beach of Quintas do Sul and is exposed to the full force of the Atlantic Ocean.

Water treatment in fish farms with recirculation systems is necessary to minimize the amount of harmful pollutants, which may hamper growth at elevated levels in the water.
The water will gradually become polluted by fish respiration, excretions and by decay of surplus feed. To achieve a high degree of recirculation and very low water demand, these components must be removed from the water: carbon dioxide (CO2), ammonium (NH4), nitrite (NO3), harmful bacteria, particles and organic matter.

The solution was an installation of a closed loop fish farm and treatment processes for recirculated sea water utilizing the AnoxKaldnesTM MBBR technology. The MBBR technology is a fixed film system where plastic carriers act as a protected surface area for bacterial growth. Low maintenance, stainless steel aeration grids and effluent screens provide oxygen and mixing energy and retain the media in the reactors.

In summary, the AnoxKaldnes MBBR system at Aquacria is able to achieve very low effluent concentrations of ammonium and nitrite.  High nitrification rates seen in batch tests with biofilm carriers spiked with ammonium show that the nitrifying biofilm has the ability to remove a lot more ammonium if the ammonium concentration in the main fish basins should increase. The treatment process proves to be reliable and operator friendly.