Self Cleaning Denitrification
Denitrification as a stability factor in fish farming
Denitrification plays an important role in RAS with low water exchange. Different levels of nitrate are tolerated depending on the fish species. In general, it can be said that denitrification becomes essential at a water exchange rate of 600 l/kg feed and less. Even slightly elevated nitrate levels can cause a reduction in the feed convention ratio, while significantly increased levels reduce the general well-being.
In contrast to nitrification, the classical "biofilter", the denitrification process does not require oxygen. It must even take place under the exclusion of oxygen. However, it is dependent on a sufficient concentration of carbon. In fish farms, the carbon content in the water is usually not sufficient to keep the denitrification process going. Therefore an additional source of carbon is added to the process.
The problem with the cleaning...
A relatively large amount of biomass is built up in denitrification. To provide the denitrifying bacteria with sufficient space to settle, the reactors are filled with special media. These provide a high specific surface area as a colonisation area, but also tend to clump together quickly. Clumping inhibits the water flow and reduces the stability of the filter performance.
In contrast to classical biofilters, denitrification reactors cannot be mixed with air, as this would increase the oxygen content. The use of other gases is technically complex.
Denitrification reactors from WATER proved are completely self-cleaning and yet do not use gases during continuous backwashing. This makes these filters simple and efficient. Our denitrification reactors are available in many different diameters. We supply filters up to 3 m diameter in PE, larger diameters are built as concrete basins.
An intelligent control system allows the amount of carbon introduced to be adapted to the amount of feed and regulates the flushing and running times. Graphic-based operating elements give the operator an overview of the status and function of the filters at any time. It can of course also be accessed from mobile devices.
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