I took a tour this week that blew my mind and I have been dying for a few spare moments to tell you about it. A few friends of mine from the fledgling Sustainability NPO we recently founded, Sustain Jefferson , spent a few incredible hours touring Growing Power this past Monday. Growing Power is an Urban Ag facility that claims to grow enough food for 2000 people on 2 acres. With a claim like that I was drawn like a moth to flame. Their website offered some clues to their system-vermiculture, aquaculture, and several greenhouses. The site filled in the details and inspired me in a way that no other has since I was originally introduced to Permaculture and Bill Mollison.
What excited me most about Permaculture was the sheer common sense of it all. Taking wastes and turning them into resources to allow you to reap the benefits of both in one integrated system continues to fascinate me Aquaponics, especially in the uber simple system that Will Allen of Growing Power sets up, fits the bill perfectly.
Aquaponics takes the aqua from aquaculture and ponics from
hydroponics and melds them with a healthy dose of applied Permaculture. Aquaculture is the farming of fish in indoors in recirculating water tanks. The single largest waste from this system is that housing thousands of fish in a closed system fouls the water right quick. Hydroponics is a system of growing plants in a nutrient water medium, which of course begs the question of where the nutrients come from.
Aquaculture attempts to solve these problems, and routes the waste water from the aquaculture tanks through a hydroponic system to provide the nutrients for the plants, which help to clean the water and significantly reduces the filtration needed. Even at this level I love the idea. Growing Power puts this system into overdrive.
What Will Allen and some others are doing is experimenting with what is considered by most to already be an experimental way of raising fish and plants. First off Will has completely done away with the filtration system. He has also done away with any commercial feed, preferring instead to grow his own. See the underlying foundation of Growing Power is worms.
Readers of this blog know that I am a firm believer in Vermiculture
as a means to reduce, even recycle, waste and turn out some freaky good fertilizer. Growing Power does this on an almost industrial scale-using hundreds of bins (pictured) like mine to process literally 1o’s of thousands of pounds of waste into worm castings.
The other great thing that worms do is, um, breed. In fact in perfect conditions composting worms will double in population every 6 weeks. Growing Power uses the immense amount of castings to provide the growing medium for their greenhouse operations and then uses the surplus worms as a significant portion of the feed for his thousands of Tilapia in the aquaculture tanks.
Back to the filtration method. Growing Power uses plants, specifically water cress, to filter the water. As with most of the systems at the site, it is simple and uses mostly reused items that are common in an urban environment. In this case reclaimed sump pumps water from the bottom of the 5′ deep tanks to 30′ long flats of cress. The flats are very slightly sloped, and as the water slowly makes it way through the pea gravel bed that serves to anchor the cress roots it is cleaned of virtually all of the excess waste. Will Allen was not real long as specifics when asked about ratios of cress to Tilapia, he is an instinctive innovator… he just knows it works. Several PhD types have also toured the facility and are adamant that the system should not work. Yet, Will adds with one of his huge grins-he has been doing it for 3 years and has only lost one fish. Time to rewrite the textbooks!
So what gives? Will Allen (the giant in the blue sweatshirt) is convinced that the few handfuls of worm
castings he adds to the cress flats are the difference. The castings are chock full of rich living bacteria and fungus cultures, and it is these that Will believes supercharges the cress flats with filtering capability. After seeing the vibrance and life of his greenhouses, the obvious health of his fish, and the numerous innovation that seemingly turn up at every corner-I believe him. Heck, that is how wetlands are supposed to work, right?
Anyone who knows me can see where this is going. Will’s newest aquaculture houses are built in simple plastic hoop houses in an attempt to cut costs. He does a lot of mentoring in the 3rd (and 4th) worlds and is trying to get the system down to its bones. The last house he took us through was built for $5000 plus labor, and it houses 7000 tilapia and 2500 Lake Perch in addition to 300 sq ft of water cress and several hundred pots of greens and vegetables that were basking in the warm humid air. The next biggest problem to overcome is how to make it Peak Proof by removing the dependence on the second hand natural gas pool heater he is using. It will certainly add significantly to the start-up costs, but a combined solar water heating and wind turbine dumping into a heating element after charging a few batteries for lighting seems like a great primary heating system with a propane backup. This could also be modified to run on methane from a digester. The owner of the farm I am using to grow my market garden has plans for one already drawn up…
Looks like I have a winter research project!
It was truly inspiring to see people in the heart of an the poorer parts of Milwaukee making a difference, growing sustainable and nutritious food, and spreading the word about simple commonsense systems that work.
Filed under: Aquaponics, Permaculture, Sustainable Development, The Natural Step