Companies in the food sector, especially those in high water consumption segments such as the meat and dairy industries, face multiple challenges: strictly complying with national directives, anticipating regulatory changes and turning production waste into business opportunities.
Wastewater generated by the food industry comes not only from production processes, but also from water used in cleaning operations and, in general, from all water used in the facilities.
For this reason, the composition of wastewater presents considerable variability, depending on seasons and production processes. These waters tend to be rich in nutrients, mainly carbonaceous organic matter (COD - Chemical Oxygen Demand and BOD - Biochemical Oxygen Demand), as well as nitrogen and phosphorus.
Nitrogen Management in Wastewater
Although anaerobic treatments are highly efficient in removing a large part of biodegradable COD, their main limitation lies in their reduced capacity to remove nutrients such as nitrogen and phosphorus.
Therefore, companies must pay special attention to the discharge limits established for nitrogen forms (ammonia, nitrates, nitrites, organic nitrogen and total nitrogen) and phosphorus. It is essential to carefully evaluate the need to implement biological nitrification/denitrification and phosphorus removal processes in the treatment chain, for example, after anaerobic processes.
Regarding nitrogen management, combined nitrification and denitrification processes allow the transformation of ammoniacal nitrogen into gaseous nitrogen. Of these two biological processes, nitrification is undoubtedly the slowest, which significantly impacts the total volumes required for purification processes and, consequently, the level of investment needed. In addition to their slow growth, nitrifying bacteria are extremely sensitive to temperature variations and to the qualitative and quantitative fluctuations characteristic of wastewater from the food sector. Treatment plants are likely to experience periods in which nitrogen concentrations in the effluent are unstable and do not comply with regulatory limits. Another common scenario is that the productive capacity of the facilities is limited precisely by the capacity of the treatment plant to remove nitrogen.
Currently, the technology market offers solutions capable of increasing treatment capacity and stability without increasing existing biological volumes, improving, for example, the performance of conventional activated sludge plants. For new treatment facilities, it is possible to directly implement compact and efficient technologies, reducing civil works and minimising the impact of treatment on the facilities.
The AnoxKaldnes™ MBBR (Moving Bed Biofilm Reactor) and AnoxKaldnes Hybas™ (hybrid biofilm and activated sludge system) biological systems are widely used in food wastewater treatment due to their high efficiency per unit volume, greater stability against wastewater variations, and the possibility of being integrated into existing infrastructure to increase treatment capacity safely and quickly.
The implementation of AnoxKaldnes™ treatment plants generally allows the treatment capacity of an existing conventional activated sludge plant to be doubled and reduces by up to 70% the volumes required in new installations.
Conclusion
Environmental sustainability has become a strategic factor for many companies, especially those in the food sector, which have traditionally valued their connection to the territory and the development of a circular economy. In a European context, community directives on wastewater treatment and the objectives of the European Green Deal are driving industries to adopt more efficient and sustainable technologies. Various European and national funding programs offer significant incentives to support modernisation and optimisation projects for treatment plants, facilitating the transition towards more efficient processes such as those described in this article. Investment in these technologies not only ensures regulatory compliance, but also represents an opportunity to improve competitiveness and reduce the environmental impact of industrial operations.
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