Aquaponics can function at many scales, with different applications in a permaculture design. For zone 4 & 5 lake wild areas it functioned as an earth repair design element stopping algal blooms and growing fodder. In Zone 0 inside the home, it functions as a micro aquaponics kitchen garden and educational ecosystem.
World’s largest aquaponics system developer – miniturises Aqua Biofilter technology, down, into an Aquaponics Kitchen Garden. Story by Home Ecology.
The worlds largest aquaponics installation has cleared up Lake Taihu’s horrific toxic algal bloom. How did they do it and what next for technology?
Lake Taihu experienced its worst ever algal bloom at the height of summer, pushing researchers to search for new solutions. They decided to try a new technology, Aqua Biofilter, that is designed to remove nutrients that fuel algal blooms. Plants take up nutrients, but it is the biofilm on the roots that capture nutrients and accelerate de-nitrification, a natural process that usually occurs in the lake sludge. An ambitious aspect of the project was to launch the world’s largest aquaponics system over 4 acres in size, using new technologies in combination with old world bamboo that is used in traditional Chinese building. From a permaculture perspective, a multiplier benefit is that the Canna lily is a highly nutritious livestock fodder crop, and was a key species to integrate into this circular bio-economy approach. For the purpose of nutrient management at the mega-river catchment scale of the Pearl river delta, working with individual landholders, will take several decades, to change the land management practices of the surrounding catchment. In the meantime end-of-pipe solutions were needed with intra-lake treatment. The permaculture approach taken was to understand where are the nutrients coming from, and where should they be going back to, whilst waiting for land owners to change their soil, water, plant and animal management practices. The Canna lily can be harvested and move the unwanted nutrients from the lake, into a form of starch and protein, that was needed by livestock nearby. Permaculture solutions can be creative at the river delta scale like the Aqua Biofilter approach over 4 acres in size, right down to small scale at 1/2 square foot for the Aquaponics Kitchen Garden, making aquaponics a scale-able and creative approach for consideration in earth repair projects, small scale food production where suitable land, soil or water is not available, as well as a contributor to a circular bio-economy approach of recycling nutrients within a bioregion catchment.
Biomimicry of peak wetland ecosystems
The technology is part of the new wave of processes that biomimics nature, using biomaterials and recycled materials that can remediate and restore nature’s balance with non-toxic and sustainable processes. The concept was adapted from natural wetlands that process nutrients and pollutants with plants. Mature wetland ecosystems often develop self-sustaining floating wetlands that mop up pollutants. Most lakes and urban wetlands are highly modified or recently built, with polluted inflows, making it necessary for earth repair specialists (often with the help of policy makers and Local Government engineers in the experience of Aqua Biofilter) to try and mimic nature and the symbiotic processes as part of a holistic management approach. Taking the best of what nature has developed to tackle pollutants that run-off from urban, industrial and rural areas, Tom Duncan developed the Aqua Biofilter floating wetlands technology over the last 10 years working on projects around the world.
Tom decided to take his experience from the large scale aquaponics system in Lake Taihu and other projects in Australia and Malaysia, and miniaturise the technology down into a tabletop system. The concept was to try and provide a kit that anyone can assemble, and would be educational for school kids to learn about biomimicry, nutrient cycles and how ecosystems evolve in co-dependency, whilst for people living in apartments in can provide a small amount of herbs and greens, whilst bringing back a nature connection inside city living apartments. As Tom was working around the world developing floating wetlands projects, living in cities, dealing with city traffic and pollution, having a garden at home was a necessary item. He decided to take his Aqua Biofilter experience with aquaponic floating wetlands and scale it down into an Aquaponics Kitchen Garden kit that could grow some herbs and greens. Species that handle wet feet include mint, Vietnamese mint, basil, lettuce and variety of other species that grow well in hydroponics systems.
The Aquaponics Kitchen Garden kit is not trying to be a veggie garden replacement, but living in small apartments in cities, people need a small garden that can grow some plants, and engage with biology in what otherwise is a dense urban polluted environment. The kit will include an option for a low energy LED grow light. A crowdfunding campaign will be happening in February – if you would like to pre-order a system for home, school or office, you can subscribe to the Home Ecology newsletter at www.homeecology.net and you will be notified when the crowdfunding campaign goes live and accepts pre-orders (at a nice discount we have been told).
Having a pet fish in the city can raise one’s spirit, and is a real alternative to cat or dog ownership which requires sufficient open space to exercise dogs, and also the required importation of meat to feed the animal. Siamese Fighting Fish also known as Betta fish are well suited to a worm farm system if the worm is prepared appropriately as food. Closing the loop in aquaponics enhances the overall environmental sustainability of the system. Tom decided to incorporate a moon gate façade that acts as a fish hide, in a design homage to the Feng-Shui approach that mimics the moon form, into the garden, to bring that awareness and presence into the living space, acknowledging that the moon influences the tides and water movements on earth. Adding a small pump to recirculate water and waste also adds a dynamic element to the fish tank, boosting plant growth aquaponically and giving the fish a dynamic environment to swim within and be happy.
On top of the grow tray which filters the fish waste water, is a permaculture keyhole pattern plate that holds the grow pots in the most space efficient design. Careful consideration was given to how to best design the plant grow pots to make use of limited space with either 8 or 6 plants fitting comfortably within ½ a square foot using the permaculture keyhole pattern. Designing the system to allow the fish to express it’s ‘fish-ness’, or the fish to express it’s inherent character and habits, is essential when designing a home for an animal and is a key part of the holistic management approach and biomimicry that people like Joel Salatin at Polyface Farm have demonstrated so effectively. Fish are no different, and require the fundamentals that they access in nature. So the grow tray and grow pot plate was designed to have two plants growing directly down into the tank to provide habitat for the fish, whom enjoys sleeping in the plant root zone. Whilst 4 grow pots are inside the grow tray and have roots contained, accessing more nutrients from the recirculating trickle pump system, such as herbs and greens.
Floating aquatic plant roots are important to many fish in their wild habitat. The fish tank is no different, as the root biofilm made up of complex bacteria and aglal bio-associate species slough off and nourish the skin of the fish as it rubs against the roots, swimming and darting through the rhizosphere. The bacterial and algal root biofilm improves the skin condition of the Betta fish (and many other fish such as goldfish for that matter), preventing skin disease and gives the fish a brighter colour and relaxed demeanor. If more fish tanks incorporated aquaponics on top, fish would be happier and have improved vigor and health. In nature, fish regularly come into contact with the roots floating in the water, as the floating aquatic plants provide habitat and safety for fish to sleep within and feel safe. In the same way Joel Salatin provides pig homes in the forest at Polyface farm, with plenty of places for pigs to rub their backs against, and snout around in the soil, many fish species need plant roots to swim up against, sleep within and gain health improving beneficial microrganisms and algal bio-associates from. The gut ecology and biome in humans, has a similar role to fish skin around the gills, because fish rely on gill absorption for fundamental sustenance. Betta fish are in some ways unique, in that they have evolved in South East Asia, in what many describe as small shallow ditches near rice paddies, and have evolved to be able to breath the air directly via gulping, instead of via gills, so are uniquely adapted to live in diverse human habitats, if appropriate care and habitat is provided. It is recommended however to use a small pump in the aquaponics system – a 2 watt pump is sufficient for the Aquaponics Kitchen Garden.
Tom hopes the crowdfunding campaign will bring aquaponics fans to his project and get it up off the ground. People can follow the crowdfunding campaign and get a discount pre-order by subscribing to www.HomeEcology.net
Aquaponics science and research by Tom Duncan
Lake Taihu has extensive aquaculture industry that suffered mass die offs after toxic algal blooms took over the lake, threatening the future of the aquaculture industry, and also the drinking water for 30 million people. Aquatic ecosystems that rely on freshwater were decimated.
The research team chose plant species that would beautify the lake, and also provide rapid root growth which serve as habitat for native fish to spawn and provide refuge from the toxic algal bloom. Further benefits were realized using Canna lily that can also be used as a fodder crop for livestock. Three months after project implementation, the water cleared completely with no visible algae and water transparency improved by 250%. The plants had soaked up the excess nutrients, cutting off the nutrient supply that algal blooms require to grow. Roots exert a strong biofilm that captures nutrients and pollutants, and de-nitrifies the water allowing natural balance to be restored.
The emerging science of aquaponic floating wetlands suggests that floating wetlands are up to 5 or 10 times more effective at removing nutrients than sediment rooted open wetlands in terms of space requirements, because the larger biofilm surface area of the roots, compared to the leaf area in open sediment rooted wetlands is so different. Roots provide far greater surface area than leaves, and for that reason are recommended for inclusion in wetland treatment systems, living machine types of waste water treatment plants, and farm dams that accumulate too much nutrient and have algal blooms or excessive aquatic weeds. For example 200 square feet of aquaponic floating wetlands provides the same amount of biofilm surface area of approximately 1 acre of sediment rooted open wetlands. As urban, industrial and rural run-off threatens river health and marine environments, more intensive methods such as aquaponic floating wetlands will be required to remove the nutrient levels. Australia’s great barrier reef and many other reefs around the world are under threat from nutrients running off unsustainable farming practices, sugar cane, industrial mono-cropping and unsustainable feedlot livestock operations. Whilst we would like these unsustainable land managers to change their practices, with Permaculture, Holistic Management and Regrarian processes, the Great Barrier Reef can’t wait for that, and intensive interventions that remove the nutrients before flowing out into the marine environment are necessary. The necessary nutrient removal is achievable at a low cost, and as simple as installing floating wetlands in dams adjacent to farm run-off zones.
Table. Parameters on average in different test areas and their category of environmental standards of surface water*
* Data monitoring is in treatment zones under the study, with differing coverage ratios of surface area, shortened to Cov. & Class of water as CLASS, respectively. Class V is very degraded & Class I China’s National Lake Water Quality Targets, similar to ANZECC guidelines, however, the values differ between countries and ecosystems, according to aquatic environment behaviour and ecological signals.
Some 200 square foot of Aqua Biofilter provides a root biofilm surface area of approximately 1 acre of open wetlands, delivering incredible rates of nutrient and pollutant removal. The lack of operational expenses makes the technology attractive to local governments and water managers who need quick results at an affordable price. The benefits of floating wetlands go beyond improving water quality, by also serving as habitat for diverse water fauna, enabling complete restoration of aquatic ecosystems. Company CEO Tom Duncan hopes to work further with communities and Local Governments that would like to develop biomimicry water solutions, and bring back living ecosystems to restore degraded catchment. Please contact Tom at Aqua Biofilter or Home Ecology for information, and for further information on small scale systems, visit Aquaponics Kitchen Garden
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