Nexus of water and food security

The innovation-field “water technologies, resource recovery, and scale-up” at the Fraunhofer Institute for Interfacial Engineering and Biotechnology is researching hydroponic systems for “soilless” agriculture. These systems conserve resources, have a reduced environmental impact, and make plant cultivation possible even in harsh regions.

Our aim is to provide solutions to the global challenge of ensuring food security in the face of the resulting conflicts of climate change and water scarcity.

What is hydroponics?

Agriculture is one of the sectors with the highest water consumption globally ­– therefore, new concepts for water-saving methods of crop cultivation are in demand.

This is why Fraunhofer IGB is working on hydroponics, which is a water-efficient agricultural production system. Unlike traditional soil-based agriculture, hydroponic systems to not rely on soil to grow plants. In hydroponics, plants are cultivated in closed, water-based systems, which prevent water from seeping into the ground and reduce water loss through evaporation. Plants in hydroponic systems obtain the necessary nutrients from a nutrient solution.

Advantages of hydroponic crop cultivation inlclude:

•       Water efficient crop cultivation
•       Greenhouse hydroponics allows year-round plant cultivation, even in Central Europe
•       Use of reprocessed wastewater as water supply is possible
•       Use of nutrients, which are derived from organic waste or wastewater
•       Energy requirements can be met using locally generated, renewable energy sources

Interdisciplinary collaboration of various competencies

•       Water management: process engineering and digitization
•       Water quality: Analytics and sensor technology, hygiene, and microbiology
•       Nutrient management
•       Plant cultivation and horticulture

Our research explores how to achieve maximum agricultural gain with minimal water usage, under what conditions water can be reused (e.g. from reprocessed municipal wastewater), and how nutrient sources like wastewater or food waste can be utilized for nutrient provision.

Our goal is to loop water and nutrients together, contributing to both food security and resource efficiency.

Nutrients from wastewater

For example, anaerobically treated wastewater still contains ample inorganic phosphate- and ammonium salts after the decomposition of its organic compounds – nutrients that are crucial in agriculture. In the HypoWave research project, the IGB, in collaboration with partners, investigated whether anaerobically treated municipal wastewater, due to its nutrient content, could be reused for hydroponic plant production. The result of a pilot experiment with lettuce plants showed that only a small additional nutrient supply was required for healthy growth, demonstrating the successful reuse of nutrients contained in the wastewater.

Nutrients from organic waste

Mineral nutrient salts for hydroponic plant cultivation can be expensive and not always affordable in rural areas of Africa. Because of this, we are investigating how we can process locally available organic resources, such as plant and animal residues, into a hydroponic nutrient solution, in the NexusHub project. Through anaerobic fermentation and subsequent sequential biological treatment in a Sequencing Batch Reactor (SBR), we were able to convert the residues into plant-available nutrients.

National and international network

In Germany, we are researching the possibilities of treating municipal wastewater for agriculture in the HypoWave project and its follow-up project HypoWave+, working alongside an interdisciplinary consortium coordinated by the Technical University of Braunschweig (Institute for Urban Water Management, Prof. Dr. Thoms Dockhorn).

Since starting our GreenUp Sahara activities, we have been in regular contact with internationally operating organizations such as Oxfam and the World Food Program (WFP).

We are also deepening our collaboration with Stellenbosch University in South Africa in the field of hydroponics with recycled waste within the Fraunhofer Innovation Platform for the Water-Energy-Food Nexus at Stellenbosch University (FIP-WEF@SU).

Local solutions for global challenges

The developed technologies are particularly relevant for water-scarce regions, especially in Africa/East Africa and the Middle East.

Given the lack of rainfall in recent summers, water efficiency and hydroponic agriculture are becoming increasingly important in Germany and Europe as well.