27th August, 2013

Contributor:  Groupe One ASBL, Brussels

What growing techniques to use when soil is not available

Aquaponics is the combination of two production methods: Aquaculture (growing fish) and Hydroponics (growing plants in nutrient rich water). At the heart of the system, lies the symbiotic relationship between fish, bacteria and plants.  Water flows in a closed loop system from the fish tank to the plants growbeds and back to the fish. Beneficial Bacterias living in the water and growing medium transform fish waste (ammonium) into plant accessible nitrites. Therefore, the water is returned filtered and cleaned to the fish (an excess ammonia is lethal for fish). Thus we obtained a highly effective production of both vegetables and fish.

The technique has been used for centuries in around the world (Aztecs, ancient Egypt and Asia). The modern version has been mainly developed in Australia and the US for the last 20 years. Very open source, a large body of data exists on the Web and examples of aquaponic farms exist throughout the world. However, the technique has only been recently “discovered” in Europe. As a result, this research field is now steadily growing over here.

Motivations

The urban environment is characterised by a lack of access to soil due to both the built infrastructure and soil contamination (often the heritage of an industrial past). Therefore, there is a need to research soilless production method. In addition, hydroponic is known to have much higher yield than conventional soil based agriculture. This is of interest in places where the population density is high and available land is low.

Despite clear production benefits, hydroponics relies on fertilisers and therefore increased sustainability requires research into alternative plant food. Using fish waste is one way to improve this with the added benefits of obtaining fish protein too.

Social inclusion also played a part in the initial analysis has it is generally the wealthier social class that has access to a private garden. This technique potentially allows people without garden to envisage food production.

Results

Following the identification of the technique by Groupe One, a visit was organised to the Centre of Aquaculture of Sterling (UK) which has the most advanced research in the EU. Upon return, a Brussels based project was launched: “Aquaponiris”. The objective of the project is to disseminate the technique, gain local knowledge and provide training to a low qualified public.

So far the achievements of the programme are:

• Building and running a 10m² aquaponic greenhouse in a business centre (see image)
• Production of communication support (flyer, information panel, website to come)
• A series of short information sessions (1-2hrs) for all types of audience (Children, Architecture and Urbanism Students, Agronomist Students, unemployed, local urban farming organisation)
• A partnership with a local employment agency to set up a 2 week long training course for the unemployed – the course combines technical aspects (aquaponics) as well basic managerial skills (accounting and business models)

The running of the pilot training (end of june 2013, the next course is scheduled for the end of September)

Benefits

Environmental

The technique allows for a very resources efficient production of both vegetables and fish protein. Fish is one of the most interesting animal protein to produce (being cold blooded they have a very high level of energy conversion). As it is a closed loop system, fish waste is really a resource for plant production. Moreover, the process prevents nutrient rich water to be released in the environment. This has clear implication for traditional aquaculture.

Since the technique relies on the direct relationship between fishes, bacteria’s and plant, , any chemical use is prohibited for plant treatment as they would directly harm both fishes and bacteria. Hence, the technique has to be organic by default.

Hydroponic is a much more water efficient production system than soil based. This has very positive impacts in rain-deprived area.

The system can potentially be designed to be self-sufficient: energy from renewable and integrated fish food production (insects based).

Finally, the system could allow for a virtually zero-food mile production.

Social

Education: Aquaponics is a fantastic tool to educate about a wide range of issues and subjects: fish and plant biology, chemistry, physics, mathematics, organic gardening etc… The re-created ecosystem allows to witness process that generally occur on large time or geographical scale such as the Nitrogen Cycle. Also sustainable development principles are made visible: Closed loop thinking, Resilience, Integrated System, Multifonctionnality etc… Finally seeing a system, ultimately leads to questions about the current food system.

Accessibility: Since it is a soilless technique, access to a garden is not required to start producing food. While high-tech system exists, the majority of examples are made with re-used material (examples IBC containers) which makes building such system very cheap. Due to the high productivity a small area could potentially provide for a whole family (including animal protein).

Greening the city: Since it can be deployed in highly urbanised/mineralised environment, this technique allows green space to re-appear in places where they are most needed.

Economical

The primary economic output is the development of local production and the sale in (very) short supply chains. Moreover, the development of aquaponic farms could stimulate the development of whole new sector of activity: from the equipments needed, to the fish stock, fish food (link to the developing insect for food industry), to farms themselves and the transformation of food (eg: fish smoking) and new model of delivery. The sector will use both highly qualified people (agronomist to low qualified (handling)

Since such a farm could potentially be set-up anywhere, choosing a disused building (in or on) in order to regenerate urban area seems attractive.

Pro and Contra

Pro

• It is a very efficient food producing system
• It’s an interesting alternative to classic hydroponics or a great waste management system for aquaculture
• It is embodies core principles of Permaculture: maximising outputs while reducing inputs in accordance with a careful analysis of what the local (urban) environment provides
• Fantastic awareness raising tool
• Clear potential for urban regeneration

Question to the network

• What are your views on Aquaponics as a tool to promote urban agriculture?
• What are your views on offsoil production as way to maximise vegetable production in densely populated areas and allow the developpement of commercial urban farms?
• What successful business models of commercial urban farms do you know?