BioBioCarrier

Development of fully biodegradable growth media in aquaponics with the release of nutrient additives for biological water treatment

Support programme

This project is funded by the "Central Innovation for SMEs" (ZIM) funding programme of the Federal Ministry for Economic Affairs and Energy (BMWi) as a cooperation project between a company and a research institution.
Logo of the funding partner.

Objective

The aim is to develop a biodegradable growth body. In addition to biodegradability, a functional extension of the conventional product is also to be realised. The development of a formulation for a bioplastic compound that degrades completely but not too quickly in aquaponics systems represents the first technological product development. This will ensure the economic efficiency and longevity of the growth bodies in treatment processes.

Up to now, conventional growth bodies have only provided a settlement surface for the biofilm. The new degradable growth bodies are intended to change this. These are to be specially functionalised for use in aquaponics systems. These systems contain hydroponic plants that need to be supplied with mineral nutrients such as nitrogen, phosphorus and other minerals and trace substances. These nutrients are extracted from the water and must therefore be constantly added to the system. The basic nutrients are introduced by the fish culture or by feeding the fish with artificial feed, so-called pellets. All other mineral nutrients must be added manually; this is usually done in the form of additional nutrient preparations. By using biodegradable and functionalised growth bodies, these nutrients can be added continuously via the growth body itself, making an additional product and additional working time for testing and application superfluous. For this purpose, the bioplastic used for the growth bodies is to be additivated with mineral nutrient preparations. As the growth bodies degrade during use, these nutrients are gradually and continuously released and are available to the plants contained in the system. This ensures long-term application of the functionalised growth bodies, which minimises manual intervention and therefore working hours to maintain the operation of the corresponding plants.

Biodegradable growth bodies also solve the disposal problem, which presents plant operators with disposal problems and monetary expenses when converting or restructuring the plants, as the degradable growth bodies are completely compostable.

The growth bodies to be developed will be designed for complete use in a moving bed reactor and for partial use in conjunction with conventional growth bodies. This gives users the option of using the newly developed growth bodies depending on the requirements and possibilities of the respective application. The difference in the customised developments is the loading with additives and nutrients. The development tasks with regard to material production are primarily carried out for a high additive and nutrient load, as this is where the greater challenges are to be expected. The systems are also relevant for partial use with conventional growth bodies and for use as a long-term stable system with a degradation time of more than 1 year.

Contents

Bio-carriers are extruded plastic bodies which, thanks to their geometric design, offer the largest possible surface area for microbiological processes. They are used in recirculating aquaculture systems (RAS for short) and aquaponics as well as in wastewater treatment in biological filters (biofilters for short) and serve as a settlement area for the desired nitrifying bacteria. Almost all modern growing media currently in use are made of petrochemical plastics, mostly HDPE (high-density polyethylene), and do not fulfil any additional functions apart from providing a large surface area for the settlement of beneficial, so-called nitrifying bacteria.

Furthermore, the formation of microplastics, e.g. through abrasion, cannot be ruled out with conventional growing media. This is particularly critical in systems that contain aquatic life, such as fish. Accordingly, there is currently a lack of growing media made from alternative materials on the commercial market. Furthermore, the inert biomass of growth bodies is simply a waste of space and resources.

Project partners

Christian Stöhr GmbH & Co. KG
Kronacher Str. 14
96364 Marktrodach

Institute for Circular Economy of Bio:Polymers
Hof University of Applied Sciences
Alfons-Goppel-Platz 1
95028 Hof

Addressed SDGs (Sustainable Development Goals)

Contact person

Prof Dr Manuela Wimmer. Research group leader in the area of sustainability and project management in water management.

Prof Dr Manuela Wimmer

Research Group Leader

Sustainability and project management in water management (NaPro)

Portrait of Dr Harvey Harbach, research group leader for resource-efficient food production in integrated aquaculture at the Institute for Sustainable Water Systems at Hof University of Applied Sciences.

Dr Harvey Harbach

Research group leader

Resource-efficient food production in integrated aquaculture (ReLe)

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