Living machines

Living Machine is a trademark and brand name for a patented form of ecological wastewater treatment designed to mimic the cleansing functions of wetlands.[1] The latest generation of the technology is based on fixed-film ecology and the ecological processes of a natural tidal wetland, one of nature’s most productive ecosystems.[2] The diversity of the ecosystem produced with this approach allows operational advantages over earlier generations of Living Machines and over conventional wastewater treatment technologies.[3]

The Living Machine system was commercialized and is marketed by Living Machine Systems, L3C, a social benefit corporation based in Charlottesville, Va. The trademark Living Machine is owned by Dharma Group, LC, the parent company of Worrell Water Technologies.[4]

The Living Machine is an intensive bioremediation system that can also produce beneficial byproducts, such as reuse-quality water, ornamental plants and plant products--for building material, energy biomass, animal feed. Aquatic and wetland plants, bacteria, algae, protozoa, plankton, snails and other organisms are used in the system to provide specific cleansing or trophic functions. The tidal process operates outdoors in tropical and temperate climates. In colder climates, the system of tanks, pipes and filters may be housed in a greenhouse to prevent freezing and raise the rate of biological activity.

The initial development of the technology in the United States is generally credited to John Todd, and evolved out of the bioshelter concept developed at the now-defunct New Alchemy Institute. The Living Machine system falls within the emerging discipline of ecological engineering, and many systems using earlier generations of the technology are built without being dubbed a Living Machine.

Contents

Design theory

The scale of Living Machine systems ranges from the individual building to community-scale public works. Some of the earliest Living Machines were used to treat domestic wastewater in small, ecologically-conscious villages, such as Findhorn Community in Scotland,[5]. Some treated the mixed municipal wastewater for semi-urban areas, such as South Burlington, Vermont (this plant closed recently).[6] The latest-generation Tidal Flow Wetland Living Machines are being used in major urban office buildings, military bases, housing developments, resorts and institutional campuses.[7]

Each system is designed to handle a certain volume of water per day, but the system is also tailored for the qualities of the specific influent. For example, if the influent contains high levels of heavy metals, ecological wastewater treament systems must be designed to include the proper biota to accumulate the metals.[8] During the “spring cleaning” season, there may be high levels of bleach in the water. This sudden concentration of a toxin is an example of a steep gradient.

Species diversity is a design goal that promotes complexity and resiliency in an ecosystem. Functional redundancy (the presence of multiple species that provide the same function) is an important example of the need for biodiversity. Snails and fish filter sludge and act as diagnostics; when a toxic load enters, snails will rise above the water level on the wall of the tank.

The above points are an incomplete synthesis of a paper by Todd and Josephson.

Comparison with conventional treatment

Björn Guterstam critiques conventional wastewater treatment for five different inadequacies that living machine systems address. This evaluation explains the basis of his five points of contention:[11]

A contained microsystem can be very successful in recycling nutrients, organic matter, and water. Depending on the toxicity and makeup of the influent, living machines can treat water to tertiary treatment standards and even reach potable standards for most or all metrics. This excellent organic recycling is possible if the biosolids are not heavily contaminated with persistent pollutants (such as aluminum, which retards biotic growth). Mixed domestic/industrial municipal influent is more polluted, so a living machine may not always be able to treat every contaminant to levels that would not stress the ecosystem that receives the effluent. In this case, more treatment is necessary, which can be achieved by drainage into constructed wetlands which provide a different type of ecosystem that provides a fresh lineup of ecological players and services that can further process pollutants.

Guterstam contends that traditional facilities require larger capital investment and demand more labor and energy costs than their ecological counterparts. It is difficult to make a generalization about economic comparisons because thus far living machine systems have only been built for single commercial buildings. The next step in the development of these systems would be a larger scale ecosystem that has more diversity and higher populations to treat a larger volume of sewage. Until there is an equivalence of scale, economic comparison between the two systems is somewhat awkward and speculative. However, it is safe to say that Living Machine systems are ecologically superior.

Conventional wastewater treatment is heavily embedded in our industrial toolkit. A worldwide revolution in wastewater treatment would require an entire industry and profession to make a major disciplinary shift from a focus on industrial engineering to ecological engineering, applied biology and ecology. Living Machine systems have yet to be made on a comparable scale to conventional treatment plants, and this “biology of scale” could bring benefits or drawbacks in efficiency.

Built components

In tropical and temperate climates, Living Machine systems can be outdoors, as the temperature will sustain sufficient biological activity throughout the winter. In cold climates, a greenhouse is used to keep water temperatures warm so that plants do not winterize. Supplemental heating may also be necessary.

Living Machine systems use screens, biofilters, plumbing, large plastic tanks, reed beds, rocks, fans, pumps and other mechanical devices. Every system is tailored to the volume and makeup of the sewage. Some are stand-alone greenhouses, while others are built into larger buildings.

John Todd and James Shaw have a patent on a device called an "ecological fluidized bed" which is essentially a pumice-filled tank with a concentric inner tank that contains wetland plants. Pumps rapidly recirculate water to maximize the filtration rate of this device.[15]

Living Machine System Process

Hydroponics and Aquaculture

Some ecological wastewater treatment systems, including first-generation Living Machine systems, employed hydroponics and even aquaculture. However, these processes are not part of today's Tidal Flow Wetland Living Machine systems.

Future horizons

In a 2000 report to the USEPA on a South Burlington, Vermont, living machine, Ocean Arks International outlined five key areas which could shape the future of this field.[28] The foremost “possible breakthrough areas” is the ongoing classification of species by the biochemical, biological and ecological roles they play and how those roles effect other species under the context of wastewater treatment. The breakthrough would be to study the function of organisms in hopes of being able to more readily and successfully manage overall ecosystem function. Browne et al. (in press) have looked into the structuring of aquatic systems for water treatment.[29]

Trophic management is used to influence entire systems by selective predation based on diagnosing an imbalance and analyzing the web of ecosystem classifications, roles and relationships. This management technique exploits the close interconnections of the food web, trophic cascade, to send a ripple down through the living community. This stewardship technique is predicated upon an advanced understanding of the conditions in the ecosystem and modeling the dynamic relationships down the trophic cascade. The trophic cascade in lakes has been researched by Carpenter and Hall.[30]

Living Machine systems have been composed largely in closed greenhouses which can only react minimally with the surrounding ecosystem, and where populations have been heavily managed to foster equilibrium. If a Living Machine were subject to the ecology of invasions, new species would be free to colonize the system, and natural selection would dictate the success of any species. This would be true ecosystem self-design and self-management partnered with human stewardship.

Photosynthetic changes, specifically the control of light exposure is another powerful management practice capable of slowing or accelerating primary production. This is similar to the idea of trophic management, except that it manipulates the other end of the food web.

Finally, there is economic potential for methane generation, market crops such as flowers, fish, tomatoes, lettuce and other foods tolerant of hydroponic conditions, useful plants or medicinals. Combined with the revenue from wastewater treatment these services could turn living machines into pollution sinks and economic generators.[31] It is well documented that a small, well-planned system in a good location can be economically viable. If a living machine can subsist in Alaska, it seems reasonable that ecologically engineered wastewater treatment can be tailored to work smoothly in warm developing countries.

Public sanitation and equitable access to water in very poor countries are grave problems. Living machines could be a low-capital approach to treating and recycling water, but skilled biologists may be a limited resource as well. A brick-pool living machine was built by Americans in Auroville, India.[32]

List of Living Machines

See also

References

  1. ^ Living Machine Systems, L3C, http://www.livingmachines.com. "Factsheet: Tidal Wetland Living Machine System -- Description and Scientific Basis." http://www.livingmachines.com/images/uploads/resources/tidal_wetland_living_machine_technology_description.pdf. Retrieved 2011-8-18.
  2. ^ United States Environmental Protection Agency. "Importance of Wetlands." http://www.epa.gov/bioiweb1/aquatic/importance.html. Retrieved 2011-8-18
  3. ^ Living Machine Systems, L3C, http://www.livingmachines.com. "Creating a Sustainable Water Infrastructure for the 21st Century" whitepaper. Kirksey PE, Will. Retrieved 2011-8-18.
  4. ^ United States Patent and Trademark Office. "Trademark Applications and Registration Retrieval" page. http://tarr.uspto.gov/servlet/tarr?regser=serial&entry=76264897. Retrieved 2011-8-18.
  5. ^ Ecovillage Findhorn: Biological Waste Water Treatment
  6. ^ www.epa.gov/owmitnet/mtb/living_machine.pdf
  7. ^ McNair, Dave. "The Tao of Poo: Can Worrell's Green Sewage System Save Water and Planet?" The Hook. June 11, 2009. Retrieved 2011-9-24.
  8. ^ Todd, Nancy J. 2005, A Safe and Sustainable World: The promise of Ecological Design. Island Press, Washington D.C.
  9. ^ Todd, John and B. Josephson. “The Design of Living Technologies for Waste Treatment.” Ecological Engineering 6 (1996) 109-136.
  10. ^ Todd, John and B. Josephson. “The Design of Living Technologies for Waste Treatment.” Ecological Engineering 6 (1996) 109-136.
  11. ^ Guterstam, Bjorn. 1996. Ecological engineering for wastewater and its application in New England and Sweden. Ecological Engineering 6 (96- 108).
  12. ^ Wilson, Duff. "Fateful Harvest: The True Story of a Small Town, A Global Industry and a Toxic Secret." Harper, 2002.
  13. ^ Guterstam, Bjorn. 1996. Ecological engineering for wastewater and its application in New England and Sweden. Ecological Engineering 6 (96- 108).
  14. ^ Todd, John and B. Josephson. “The Design of Living Technologies for Waste Treatment.” Ecological Engineering 6 (1996) 109-136.
  15. ^ John Todd et al. "Ecological fluidized bed method for the treatment of polluted water." US Patent #548U6291
  16. ^ Brady, Nyle and Weil. The Nature and Properties of Soil 14th ed. Prentice Hall
  17. ^ Teal, John. 1997, “Contribution of Marshes and Salt Marshes to Ecological Engineering.” Chapter 16 in C. Etnier and Bjorn Guterstam. Ecological Engineering for Wastewater Treatment, 2nd Ed. CRC Press, Boca Raton.
  18. ^ Pike, E.B. and E.G. Carrington, 1979. The fate of enteric bacteria and pathogens during sewage treatment. In: A. James and L Evison (Eds.). Biological Indicators of Water Quality. John Wiley, London, pp. 2001-2032.
  19. ^ Austin, David. “Parallel Performance Comparison Between Aquatic Root Zone and Textile Medium Integrated Fixed-Film Activated Sludge (IFFAS) Wastewater Treatment Systems.”
  20. ^ Peterson, S.B. and J.M. Teal. 1996, “The role of plants in ecologically engineered wastewater treatment systems.” Ecological Engineering. 6(1-3): 137-148.
  21. ^ Nanda Kumar, P.B.A., V. Dushenkov, H. Motto and I. Raskin, 1995. Phytoextraction: the use of plants to remove heavy metals from soils. Environ. Sci. Technol., 29: 1232-1238.
  22. ^ Austin, David. “Parallel Performance Comparison Between Aquatic Root Zone and Textile Medium Integrated Fixed-Film Activated Sludge (IFFAS) Wastewater Treatment Systems"
  23. ^ Guterstam, Bjorn. 1996. Ecological engineering for wastewater and its application in New England and Sweden. Ecological Engineering 6 (96- 108).
  24. ^ Todd, John and B. Josephson. “The Design of Living Technologies for Waste Treatment.” Ecological Engineering 6 (1996) 109-136.
  25. ^ Guterstam, Bjorn. 1997, “Ecological Engineering for Wastewater Treatment: Theoretical Foundations and Practical Realities.” Chapter 7 in C. Etnier and Björn Guterstam. Ecological Engineering for Wastewater Treatment, 2nd Ed. CRC Press, Boca Raton.
  26. ^ Sifa, Li. 1997 “Aquaculture and its role in ecological wastewater management.” Chapter 3 in C. Etnier and Bjorn Guterstam. Ecological Engineering for Wastewater Treatment, 2nd Ed. CRC Press, Boca Raton.
  27. ^ Karnaukhov, V.N., 1979. “The role of filtrator mollusks rich in carotenoid in the self-cleaning of fresh waters.” Symp. Biol. Hung., 19: 151-167.
  28. ^ "Ecological Design: Towards A Post-Engineering Perspective." http://www.oceanarks.org/ecodesign/postengineering/
  29. ^ Browne, B., R.A.F. Seaton & P. Jeffrey, In press. “Some propositions on the structuring of aquatic ecologies for water treatment.” Journal of Environmental Science and Health.
  30. ^ Carpenter, S. R. & J.F. Kitchell, eds. 1993. The Trophic Cascade in Lakes. Cambridge University Press.
  31. ^ "Ecological Design: Towards A Post-Engineering Perspective." http://www.oceanarks.org/ecodesign/postengineering/
  32. ^ Architecture for Humanity, "Design Like You Give a Damn." p.294
  33. ^ Port of Portland, http://www.portofportland.com. "Apr. 20, 2010: Green Office Building is New Home for Port Staff." http://www.portofportland.com/Media_HQ_PressKit.aspx. Retrieved 2011-8-18.
  34. ^ Jan. 26, 2011 letter, Brannen Anderson, Professor and Chair, Department of Earth and Environmental Sciences, Furman University.
  35. ^ "OTS promotes environmental stewardship with 'Living Classroom'." Akron.com. May 20, 2010. Retrieved 2011-10-9.
  36. ^ Cruger, Roberta. "Florida fountain treats wastewater." Treehugger.com. May 9, 2009. Retrieved 2011-10-9.
  37. ^ Innovative Design architects website, Northern Guilford Middle School project. Retrieved 2011-10-9.

External links