|By Rob (Beo) in Eating Local, Education, Gardening, How To, Vermicomposting | November 30, 2007|
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 a non-profit Urban Agriculture and Education facility in Milwaukee, WI 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 actual tour filled in many of the details and inspired me in a way that I havenâ€™t experienced since I was originally introduced to Permaculture and Bill Mollison several years ago.
What excited me most about Permaculture was the sheer common sense of it all. Taking wastes and turning them into resources is not something we typically think of today. Just as Forests have no waste products, Permaculture strives to promote such perfect systems in human endeavors whether it be designing a garden or linking businesses together via Natural Capitalism. Using the waste of built systems to add energy to another allows you to drastically reduce your time and energy taking care of problems and reap the benefits of one integrated system working in concert is something that 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 with an elegant solution by routing 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 before the water is returned to the fish. Even at this level I love the idea. Growing Power puts this system into hyperdrive.
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.
Vermiculture is the practice of raising worms as a means to reduce, even recycle, waste and turn out some freaky good fertilizer. Red composting worms will eat their weight in organic waste (anything from pasta leftovers to cardboard to animal manure) and then poop out â€ścastingsâ€ť that are quite possibly the best organic fertilizer available. Growing Power does this on an almost industrial scale-using hundreds of bins (pictured) to process literally 10′s of thousands of pounds of waste from local restaurants into rich worm castings-saving the restaurants thousands of dollars in garbage removal fees, and providing Growing Power with the raw material to produce tons and tons of food. Brilliant!
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 the 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 take water from the bottom of the 5′ deep tanks to 30′ long flats of cress. The flats are very slightly sloped, so only gravity is needed to move the water slowly through the pea gravel bed that serves to anchor the water cress roots. The water cress removes quite a bit of the excess nitrogen and other â€śwastesâ€ť from the water, but much of the work is done by nitrifying bacteria that lives in the pea gravel and on the plant roots. Between the bacteria and the plants the water 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 above) 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 innovations that seemingly turn up at every corner-I believe him. What Growing Power is doing is preforming a simple modeling of a natural system (a watershed) and tweaking it to produce resources more applicable to human society.
This mingling of Permaculture and Sustainable Agriculture is fascinating, but Will Allen and Growing Power are not merely working to perfect experimental growing systems. Their true goal is to provide sustainable, local food to the people that need it most and have the least access to it-the urban poor. Growing Power grows tilapia and watercress in their aquaponic system, but in most of his greenhouses before the water gets to the watercress it irrigated thousands of sq. feet of nutritious greens that are housed in pots full of worm castings. These plants are incredibly lush and vibrant-without the input of any additional fertilizer. By using â€śwasteâ€ť products at every turn Growing Power is able to drastically cut costs which allows them to survive in an urban setting with its high property values, and provide healthy sustainable food to thousands in an urban environment. In all Growing Power provides employment for over 30 people and gives meaning to hundreds more by offering educational workshops and volunteering opportunities at the farm. On site, Growing Power also raises row crops, chickens, and dairy goats giving many urban children (and adults!) a rare glimpse of where food comes from and the chance to pet a goat or hear a chicken cluck and feel a still warm egg.
Will Allen takes this even further and travels Africa and Central Asia teaching others about his growing systems. To that end, much of his current design work is focused on replicability and cost cutting. Will’s newest aquaculture houses are built in simple plastic hoop houses with the fish tanks buried in the ground to increase insulation and allow the use of inexpensive pond liner vs. stand alone tanks in an attempt to cut costs and reduce energy inputs. The last greenhouse system he took us through was built for $5000 plus labor, and it houses 3000 tilapia and 1500 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 renewables based system using simple materials is in the works. At his current site, Will is also working with some partners on an experimental methane digester sized to be useful on a municipal level. Seemingly every turn on the tour had another incredibly innovative idea pushing the envelope of sustainability be it heating greenhouses with compost piles or retrofitting broken clothes dryers to be reborn as soil sifters.
It was truly inspiring to see people in the heart of some of the poorer parts of Milwaukee making a difference, growing sustainable and nutritious food, and spreading the word about simple common sense systems that work.