Canal Restorer to River Restorer?
This greenhouse at the former historic Fisherville Mill in South Grafton, Massachusetts, sits on the banks of a canal by the Blackstone River. It is cleaning stormwater runoff and water contaminated by #6 fuel oil, also known as Bunker C oil, which leaked from underground tanks. At the end of the process, 95% of the hydrocarbons are removed without the application of chemicals, using only ecological design.
The Blackstone River can rightfully claim to be the birthplace of the Industrial Revolution in the USA as in 1790, Samuel Slater built the first water-powered spinning mill in America for Moses Brown, a founder of Brown University, in Pawtucket, RI using the Blackstone River as a power source. By October 7, 1828, the Blackstone Canal from Providence, RI to Worcester, MA was completed and became the original industrial corridor of the United States. Some say the Blackstone was the hardest working river of 19th century America with its water powering factories all along its length.
Perhaps now it will become an example of 21st century American technology that uses ecological systems thinking to clean up the wastes industrial development has left in its wake.
500 to 1000 gallons of water is pumped each day from the bottom of the canal through a filter which was designed to trap particulates and has, over time, developed its own ecosystem that begins to process the pollutants. Soon samples will be taken of the filter layers to see what organisms are present and thriving in the presence of such contaminants.
The water is then distributed to the black boxes you can see on the right of the greenhouse which contain mushrooms and other organisms. These continue to filter the water and break down the hydrocarbons and other complex compounds as the mushroom cultures and other organisms feed.
From the mushroom boxes the water goes into a series of six 700 gallon tanks, each of which is a separate ecology with plants, animals and microbes that continue to break down pollutants and contaminants into their constituent parts. The water gets cleaner and cleaner from one tank to the next until it can support fish and snails and other more complex lifeforms.
The plants floating on top of the tanks are also part of the process with the roots serving as habitat for many different organisms, increasing enormously the active surface area for biological activity, breaking down more compounds into nutrients that feed the leaves, flowers, and fruits.
After passing through the greenhouse, the water is then returned to the canal through an artificial marsh, a floating canal restorer, that continues the process of biological digestion of hydrocarbon pollutants. The marsh also takes water directly from the bottom filter in a separate cycle, cleaning it as it recirculates back into the canal.
it is the belief of the designer of this system, John Todd, that not only does this system clean the water it filters but that it also distributes micro-organisms that can help clean water downstream. He suspects that if such a system were to operate over years, it would begin restoring the waters of the canal and the Blackstone River, a result of this experiment which began last year that he will be testing for soon.
John envisions a canal with a continuous band of floating restorers cleaning the contamination and pollution of over two centuries of industrial waste, returning the canal and the Blackstone River to pristine condition.
John has completed projects similar to this before. You can read about his Urban Municipal Canal Restorer in Fuzhou, China here [pdf alert]:
These are the ecological design principles John Todd uses in building his systems. Every time I read them, I learn something new.
1. Geological and mineral diversity must be present to evolve the biological responsiveness of rich soils.
2. Nutrient reservoirs are essential to keep such essentials as nitrogen, phosphorus, and potassium available for the plants.
3. Steep gradients between subcomponents must be engineered into the system to enable the biological elements to evolve rapidly to assist in the breakdown of toxic materials.
4. High rates of exchange must be created by maximizing surface areas that house the bacteria that determine the metabolism of the system and facilitate treatment.
5. Periodic and random pulsed exchanges improve performance. Just as random perturbations foster resilience in nature, in living technologies altering water flow creates self-organization in the system.
6. Cellular design is the structural model as it is in nature where cells are the organizing unit. Expansion of the system should also use a cellular model, as in increasing the number of tanks.
7. A law of the minimum must be incorporated. At least three ecosystems such as a marsh, a pond, and a terrestrial area are needed to perform the assigned function and maintain overall stability.
8. Microbial communities must be introduced periodically from the natural world to maintain diversity and facilitate evolutionary processes.
9. Photosynthetic foundations are essential as oxygen-producing plants foster ecosystems that require less energy, aeration, and chemical management.
10. Phylogenetic diversity must be encouraged as a range of aquatic animals from the unicellular to snails to fish are as essential to the evolution and self-maintenance of the system as the plants.
11. Sequenced and repeated seedings are part of maintenance as a self-contained system cannot be isolated but must be interlinked through gaseous, nutrient, mineral, and biological pathways to the external environment.
12. Ecological design should reflect the macrocosmos in the microcosmos, representing the natural world miniaturized and reflecting its proportions, as in terrestrial to oceanic and aquatic areas.
from _A Safe and Sustainable World: The Promise of Ecological Design_ by Nancy Jack Todd
Washington: Island Press, 2005
More information at
Todd Ecological http://www.toddecological.com
Clark University Living Systems Laboratory https://wordpress.clarku.edu/fisherville/
CTI Micro-Reduction Technologies, LLC http://ctigreenpower.com/
By working with Nature, we can create miracles.
The pictures of the Fisherville Canal Restorer and Greenhouse were taken on a tour with the Ecological Landscaping Association (http://www.ecolandscaping.org) on Tuesday, August 6. 2013.
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