Innovative Aquaculture Technology and Fish Farming

As a result of research and development with various experimental aquaculture systems within the community, Aquaculture@Fraunhofer is contributing to technological progress for innovative farming systems.

Aquaculture is one of the most nutrient-efficient methods for producing animal protein. However, fish can only convert less than half of the nutrients contained in their feed into biomass. The Innovative Farming Systems research area develops new utilization concepts for already established systems such as aquatic co-cultures. Here, the nutrients used to feed the fish (fish feed) are used several times. The unused particulate and dissolved nutrients end up in the water but can be utilized by invertebrates and eventually by plants or algae to produce further valuable biomass.

Therefore, new utilization concepts such as aquatic co-cultures have great potential for the bioeconomy and circular economy.

• Plant and process engineering
• Measurement and control technology
• Determination and optimization of farming conditions for various aquaculture-relevant animal species
• Management of recirculating aquaculture systems
• Materials research
• Environmental impact

Optimization and adaptation of farming methods and technology in closed recirculating aquaculture systems (RAS) to the requirements of aquaculture-relevant species

Closed recirculating aquaculture systems offer the possibility to produce non-native species locally in a more sustainable and environmentally friendly way than in the countries of origin because they are decoupled from various environmental influences, such as photoperiod, climate and water supply. Shrimp (L. vannamei) is a good example of this: During production in the countries of origin, the environment is often heavily polluted (mangrove deforestation) and the final product is transported over long distances.

However, producing these species in closed systems requires detailed research into the optimal farming conditions.

The community addresses this issue by using various techniques such as group respirometry to determine the metabolic status of the animals. The community also uses small-scale recirculating aquaculture systems in which one or more environmental parameters can be manipulated at the same time in a targeted manner using a replicate approach.

The absence of continuous water exchange and thus the decoupling of environmental influences in a closed recirculating system allows the production of aquatic organisms with minimal impact on the surrounding ecosystems, since hardly any dissolved nutrients are released into the receiving waters. However, with water reuse rates of up to 99%, this leads to an accumulation of metabolic waste products, nutrients and minerals in the farming system. The higher the level of water reuse, the greater the demands on and challenges for the water treatment technology used.

 In the community, research is being conducted on the nature of the substances that accumulate and how to increase the efficiency of the filtration technology in terms of filtration performance and energy consumption. Conventional and innovative water treatment components are tested and optimized.

• Biofilter optimization
• Denitrification
• Germ reduction
• Wastewater treatment
• Management of recirculating aquaculture systems
  • Material research and environmental compatibility
  • Plant and process engineering
  • Tolerance studies
• Determination and optimization of farming conditions for various aquaculture species

Novel ceramic components make aquaculture farming systems and water treatment solutions sustainable and efficient. Treating process water with ceramic components makes it possible to remove undesirable substances such as off-flavor, which usually remain in the water with conventional methods. This improves the closed-loop circulation of the water. In addition, valuable substances such as various nitrogen components can even be recovered from the farming water.

• Membrane technology, high-performance biology and AOP (advanced oxidation process) systems, among others
• Nutrient recycling: Reduction and possibly extraction of ammonium and ammonia as reusable nitrogen components
  + Concentration and membrane extraction 
  + Electrochemical-catalytic denitrification 
  + Anaerobic membrane bioreactors for denitrification
• Reduction of off-flavor substances: Effective reduction of geosmin and MIB (2-Methylisoborneol) in aquaculture recirculation systems 
  + Filtration with immersed ceramic membranes combined with adsorption components  
  + Integration of photocatalytic cellular ceramics in an AOP system for tank cleaning/disinfection