A sustainable, aquaponic urban farm in the heart of Brussels.
The Brussels Region has set up an action plan to revitalise Anderlecht, a municipality on the outskirts of Brussels. A vast project to develop the historic site of the Brussels Slaughterhouses was launched in 2009. The objective of this project is to create a local and urban production pole while creating a place to live and share. Brussels hopes that by 2030, the city itself will be able to provide 30% of the food for its inhabitants.
After multiple studies carried out, the FoodMet (a food hall) emerged in 2015. The Ferme Abattoir of BIGH (Building Integrated GreenHouse) is also part of this great project: it is the first urban farm to be set up on the site. Completed in 2018, the Ferme Abattoir is located on the roofs of the newly designed food hall. This urban farm was founded by Steven Becker, a certified circular economy architect and cradle-to-cradle enthusiast, who won the call for projects to occupy the roofs of the FoodMet.
Work on the Farm’s infrastructure was carried out from 2016 to 2018 and production therefore began at the end of 2018. Thus, 2019 is the first full year of production.
The farm has 850 m² of solar panels, which helps to offset some of the electricity consumption. The farm also has its own heat pump, which stores heat from the refrigeration system at the Foodmet (food hall below the farm) while at the same time cooling the cold rooms of the butchers and retailers of the Foodmet. It is supplemented by a gas heater, if required, from which CO2 is recovered to facilitate plant photosynthesis during the day.
Thanks to its production within the city, the farm promotes the development of short circuit farming, with local distribution and sells its production directly to consumers via the local shop or grocery stores and small shops in Brussels. The herbs are certified organic (N.B.: As there is no such thing as organic fish feed, fish and tomatoes, which are produced together in a closed system, cannot be labelled organic. However, no fertilizers or pesticides are used in the production of tomatoes).
The aquaponic system installed consumes 10 times less water than a conventional fish production. Thus the farm is committed to responsible consumption of natural resources.
The construction of the farm’s facilities is based on the “cradle-to-cradle” model, an ecodesign method that allows the construction of buildings that can be dismantled and recycled, so that they can be reused and transformed once they are no longer in use: literally “cradle-to-cradle”. For example, the floor is made from recycled concrete formwork pallets and the offices from old ship containers, the windows of the greenhouses are made of polyethylene to be melted down and moulded again in case of breakage.
To listen to the members of BIGH talk about the project, go check out the video at the end of the article !
During the design phase of the project, the construction of the facilities was conceived according to the “cradle to cradle” model. That is to say that all the buildings can be dismantled and the majority of the materials are recycled/recyclable/remodulable (recycled concrete formwork pallets for the floor, remodulable polyethylene greenhouse glass, offices made from old boat containers…) in order to control the entire life cycle of the materials, “from cradle to cradle”.
Aquaponics is a system that combines fish farming and plant cultivation in a closed circuit. Natural bacterial cycles (biofilters) are used to transform fish waste (ammonia) into plant nutrients (nitrates). The plants filter this water, which is “dirty” for the fish but enriched with nutrients for the plants, which thus returns purified to the fish ponds. It’s a circular economy loop! Moreover, this virtuous system has the advantage of using no chemical fertilizers or pesticides!
BIGH Farm raises striped bass. It is a hybrid species between a freshwater white bass (Canada) and a wild sea bass (Gulf of Mexico). This species has the particularity of living in schools with high density in freshwater and resistant to warm water temperatures, which makes it an ideal species for this type of farming and their fillets are very appreciated by consumers. The aquaculture system operates in RAS (Recirculating Aquaculture System) with water that comes directly from the water table below the FoodMet. A daily renewal of 15% of this water is carried out with this borehole water.
Fish excrete in two different ways: a solid part is excreted as faeces, and a liquid part (ammonia) is excreted as urine. This ammonia-laden water will pass through a biofilter in which the bacteria responsible for nitrification (Nitrosomonas and Nitrobacter) are naturally present. The activity of these bacteria is increased by strongly oxygenating the medium and putting small porous structures in it, which give them a large surface area to multiply.
The nitrate-rich water is sent to the tomato plants, which use it as a nutrient.
The farm has a 750 m² greenhouse for growing tomatoes with a density of 2.5 plants/m². The varieties used (Saopolo and Sweden) are adapted to the aquaponic system, thanks to a grafting of the plant which allows a restricted development of the root system and a good capture of the nutritive solution. The plants are cultivated above ground in substrates composed of coconut fibre, peat and perlites, and water is added to them in droplets.
This system has many advantages and, above all, allows water savings (up to 90% water savings compared to aquaculture and hydroponics, taken separately*) and the RAS system consumes 10 times less water than a conventional aquaculture system.
The herbs are certified organic, but as the fish are not fed with organic food (this does not yet exist on the market), the water used to irrigate these herbs cannot be that of the fish. Rainwater harvested from the roof is then used. The Farm has the possibility to enhance the value of the non-marketable pots by giving the wasted soil to a farm near Brussels, thus avoiding creating additional waste while at the same time providing a service to a local grower.
The production of aromatic herbs brings an important added value because they are not products that can be frozen or transported for too long, so the short circuit is inevitable for this kind of production.
The Ferme Abattoir sells its products in its own shop, located just below the farm in the food hall. It also sells its fresh and processed products to restaurants, small shops, delis and supermarkets in and around Brussels.
The Farm also organizes animations and events (conferences, team building activities, group visits, tastings, meals…) in order to promote the project to a wide public, from professionals to the simply curious, including political representatives and schools.
In addition, the 2,000 m² of outdoor space is rented to a social reintegration association. This association grows various vegetables (e.g. salads, broccoli, peppers, eggplants…) for its restaurant, which is located in a side street. To adapt to the load-bearing capacity of the roof, the compost has been replaced by volcanic rock: lighter, porous and calorific, it stores the heat of the day and returns it to the plants at the end of the day and during the night. The small fruit trees (raspberries, blackcurrants, blueberries, blackberries) found outside are exploited by the members of the farm. The surplus water from the nitrate-rich fish is used to irrigate these outdoor crops. In the future, the Farm intends to recover and continue the production of outdoor vegetables.
In addition to the water savings made by the aquaponic system, the farm has optimized its energy consumption in various ways.
On the one hand, it produces green energy thanks to solar panels installed near the greenhouse (850 m²). The energy is sold to a distributor who resells the green energy to them, thus reducing energy costs and their carbon footprint.
On the other hand, the project was selected because 60% of the energy needed to heat the greenhouses is recovered by producing heat from the refrigerators and cold rooms in the food hall below. This energy, which was previously lost, is thus recovered and allows significant energy savings.
The environmental benefits of this urban aquaponic farm are various. On the one hand, material savings are made, especially water and several other inputs. On the other hand, green waste can be recovered in several forms (processed products, compost), which reduces the amount of waste generated and enhances production by offering different outlets. Finally, the Farm has optimized its energy consumption as much as possible by installing solar panels and by recovering part of the heat created by the refrigerators in the food hall: it is truly “integrated” into the building (hence Building INTEGRATED GreenHouse).
Energy and water savings help to limit the cost of energy inputs. However, the very large initial investment forces the Farm to sell its products at a very high price per kilo, which is not very competitive in the neighborhood in which it is located.
The farm works with many associations and companies that employ people in rehabilitation or people with disabilities. It contributes directly to the development of the social and solidarity economy in Brussels. On the other hand, it plays an important role in contributing to the development of knowledge in aquaponics and urban farming by opening its space to all publics.
According to Ferme Abattoir, it is difficult to know if this urban aquaponic farm project is replicable because each system is unique and must adapt to the context in which it is implemented. There is no definite model for this type of structure, however aquaponics is a concept that can be widely reused, especially in arid areas where water is scarce.
However, the farm is a pilot project, which serves as an experiment for this kind of large-scale aquaponic structure. It allows us to see what works well and what doesn’t work so well. It can be seen as a design tool for other similar projects.
In the case of the BIGH farm system, the barriers are technical and, more importantly, economical.
Indeed, the very high investment cost, especially for the roof, forces the farm to sell its products at very high prices in order to be profitable. The market having been overestimated when the project was conceived, the farm has difficulty selling its products. In particular, it is difficult for the farm to retain its customers since it is located in an area where products are sold at very “cheap” prices and cannot face this competition. Finally, as the farm is limited in terms of space, it is difficult to diversify or increase its production.
In order to face all these difficulties, the farm puts in place different levers. It intends to diversify its activities so that it does not only produce, in particular with on-site processing (herb tapenades, fish rillettes). It would like to further develop the reception to the public and the activities it offers on site. On the other hand, in order to sell more products, the store must be developed by offering, for example, e-commerce and home delivery. The Farm is also always looking for new partners to sell its products and ways to build customer loyalty.
Finally, one of the Farm’s assets that seems to us easily replicable is the added value it brings in the production of herbs. Indeed, guaranteeing fresh, non-refrigerated and local products is a model that can easily be transposed to other systems with different constraints, since they will be able to offer a superior quality product to their customers.
The farm’s ambition is to diversify its activities so as not to limit itself only to the production and processing of by-products (tapenades, rillettes), smoking and fish marinade. In order to ensure an income contribution, it would like to further develop the shop by offering local (Belgian) products and online sales as well as more on-site activities (group visits, company teambuilding, etc.).
The Farm would also like to make a partnership to add value to their waste with a popular association that could recover this waste and transform it to distribute it to the people living in the neighbourhood. (e.g. using cracked tomatoes to make tomato soup for a neighbourhood canteen).
Ferme Abattoir BIGH – (English Subtitles Available in the Settings !!)
Copyright CirculAgronomie 2020