Living machines
Encyclopedia
Living Machine is a trademark and brand name for a patented form of ecological wastewater treatment
designed to mimic the cleansing functions of wetlands. 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. The diversity of the ecosystem produced with this approach allows operational advantages over earlier generations of Living Machines and over conventional wastewater treatment technologies.
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.
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.
. Some of the earliest Living Machines were used to treat domestic wastewater
in small, ecologically-conscious villages, such as Findhorn Community
in Scotland
,. Some treated the mixed municipal wastewater for semi-urban areas, such as South Burlington, Vermont
(this plant closed recently). The latest-generation Tidal Flow Wetland Living Machines are being used in major urban office buildings, military bases, housing developments, resorts and institutional campuses.
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. 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.
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.
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.
outlined five key areas which could shape the future of this field.
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.
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.
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. 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.
Wastewater Treatment
Wastewater treatment may refer to:* Sewage treatment* Industrial wastewater treatment...
designed to mimic the cleansing functions of wetlands. 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. The diversity of the ecosystem produced with this approach allows operational advantages over earlier generations of Living Machines and over conventional wastewater treatment technologies.
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.
The Living Machine is an intensive bioremediation
Bioremediation
Bioremediation is the use of microorganism metabolism to remove pollutants. Technologies can be generally classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site, while ex situ involves the removal of the contaminated material to be treated...
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
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
plants, bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...
, plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
, 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
John Todd (biologist)
John Todd is a biologist working in what is sometimes considered the general field of ecological design, in that his ideas often involve applications that become the basis of alternative technologies. His principal professional interests have included solving problems of food production and...
, and evolved out of the bioshelter
Bioshelter
A bioshelter is a solar greenhouse managed as an indoor ecosystem. The word bioshelter was coined by the New Alchemy Institute and solar designers Sean Wellesley-Miller and Day Chahroudi...
concept developed at the now-defunct New Alchemy Institute
New Alchemy Institute
The New Alchemy Institute was a research center that did pioneering investigation into organic agriculture, aquaculture, and bioshelter design between 1969 and 1991. It was founded by John Todd, Nancy Jack Todd, and William McLarney...
. The Living Machine system falls within the emerging discipline of ecological engineering
Ecological engineering
Ecological engineering is an emerging study of integrating ecology and engineering, concerned with the design, monitoring and construction of ecosystems...
, and many systems using earlier generations of the technology are built without being dubbed a Living Machine.
Design theory
The scale of Living Machine systems ranges from the individual building to community-scale public worksPublic works
Public works are a broad category of projects, financed and constructed by the government, for recreational, employment, and health and safety uses in the greater community...
. Some of the earliest Living Machines were used to treat domestic wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
in small, ecologically-conscious villages, such as Findhorn Community
Findhorn Foundation
The Findhorn Foundation is a Scottish charitable trust registered in 1972, formed by the spiritual community at the Findhorn Ecovillage, one of the largest intentional communities in Britain....
in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
,. Some treated the mixed municipal wastewater for semi-urban areas, such as South Burlington, Vermont
South Burlington, Vermont
-Economy:CommutAir, a regional airline, is headquartered in the city, by the airport. The Magic Hat Brewing Company, one of the United States's larger craft breweries, is located here.One measure of economic activity is retail sales...
(this plant closed recently). The latest-generation Tidal Flow Wetland Living Machines are being used in major urban office buildings, military bases, housing developments, resorts and institutional campuses.
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
Heavy metals
A heavy metal is a member of a loosely-defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight,...
, ecological wastewater treament systems must be designed to include the proper biota
Biota (ecology)
Biota are the total collection of organisms of a geographic region or a time period, from local geographic scales and instantaneous temporal scales all the way up to whole-planet and whole-timescale spatiotemporal scales. The biota of the Earth lives in the biosphere.-See...
to accumulate the metals. During the “spring cleaning” season, there may be high levels of bleach
Bleach
Bleach refers to a number of chemicals that remove color, whiten, or disinfect, often via oxidation. Common chemical bleaches include household chlorine bleach , lye, oxygen bleach , and bleaching powder...
in the water. This sudden concentration of a toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
is an example of a steep gradient.
- Steep gradients are drastic changes in conditions throughout the system that challenge the ecosystemEcosystemAn ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
to become resilient and stable. A well-designed treatment system requires little management, so managers may intentionally create abrupt environmental or biochemical changes to promote ecosystem self-regulation. This mimics nature’s power and trains the ecosystem to adapt to influent variations.
- Designers seek to increase the surface area of contact that biotaBiota (ecology)Biota are the total collection of organisms of a geographic region or a time period, from local geographic scales and instantaneous temporal scales all the way up to whole-planet and whole-timescale spatiotemporal scales. The biota of the Earth lives in the biosphere.-See...
have with the sewage to promote high reaction rates. When organisms have ready access to the sewage, they can treat it more thoroughly.
- Ecological wastewater treatment systems are cellular, as opposed to monolithic, in design. If influent volume or makeup changes, new cells can be added or omitted without halting or disturbing the ecosystem.
- Photosynthetic plants and algae are important for oxygenatingOxygenateOxygenated chemical compounds contain oxygen as a part of their chemical structure. The term usually refers to oxygenated fuels. Oxygenates are usually employed as gasoline additives to reduce carbon monoxide that is created during the burning of the fuel....
water, providing a medium for biofilms, sequestering heavy metalsHeavy metalsA heavy metal is a member of a loosely-defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight,...
and many other services.
Species diversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
is a design goal that promotes complexity and resiliency in an ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
. 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 micro-ecosystem of a Living Machine system can be integrated with the macro-ecosystem just as ecosystems fade into one another naturally. This connection is commonly made with an outdoor constructed or natural wetland into which the effluent flows. Some living machines are partially or completely open to the outdoors, and this promotes interaction with the surrounding environment.
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:- First, conventional treatmentSewage treatmentSewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...
focuses narrowly on treating water and produces an often toxic sludge as a by-product of this cleaning process. Living machine systems can greatly reduce this sludge by conversion into biomass.
- Conventional treatmentSewage treatmentSewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...
uses environmentally harmful chemicals (namely chlorineChlorineChlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
) to disinfect effluent following precipitation of solids (sludge) from the wastewater stream. Ecological treatment uses biological processes instead of chemical inputs.
- Traditional processes do not adequately sequester heavy metals, and the sludge can also contain manmade organic compounds that are extremely difficult to break down. Some critics assert that the disposal of this sludge is not responsibly overseen in the United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, so the excess sludge is sometimes spread on public forest or even agricultural land, dumped in landfills or the ocean, and sometimes incinerated. This not only pollutes the environment with unnaturally high concentrations of toxins but also wastes a valuable resource. Living Machines can sequester heavy metals by plant uptake and the plants can be incinerated and the metals isolated in ash for safe storage. These life-giving machines convert sludge into organic tissues such as fish, flowers and medicinal plants that have human uses.
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.
- Previous generations of Living Machine systems have employed clams to filter colloidal materials and fine suspended solids. Conventional treatment runs into engineering troubles when it attempts to handle these microscopic particles.
- Conventional treatment is capital and energy intensive, whereas natural treatment is design intensive (and also management intensive if it is not well designed). The embodied fossil fuel energy in the heavy industrial infrastructure used in traditional activated sludge treatment is much greater than in the construction of a living machine system with a large greenhouse, manufacture of plastic tanks, mechanical aerators, pumps and valves among other equipment.
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
Sewage treatment
Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...
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
Applied ecology
Applied ecology is a subfield within ecology, which considers the application of the science of ecology to real-world questions. It is an integrated treatment of the ecological, social, and biotechnological aspects of natural resource conservation and management. It is also called ecological or...
. 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
John Todd
John Todd may refer to:*John Todd , early Virginia official, Kentucky soldier, and great-uncle of Mary Todd Lincoln*John Blair Smith Todd , delegate to US Congress from Dakota Territory...
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.
Living Machine System Process
- “Fixed film ecology” has superseded systems based on hydroponics or a fluid medium. In fixed film systems the wetland cells are filled with a solid aggregate medium providing extensive surface area for beneficial biofilm (treatment bacteria) growth. Fixed film ecology allows for denser and more diverse micro-ecosystems to form than does a liquid medium. These ecosystems go well beyond bacteria to include a variety of organisms up to and including macro-vegetation.
- Tidal cycles (filling and draining the wetland in accelerated tidal action--12 or more cycles per day) are used to passively bring oxygen into the wetland cells. This action mimics the same type of biological action of natural tidal estuaries. Tidal Flow Wetlands replace the need to blow air into a liquid medium and use gravity to bring atmospheric oxygen into the cell when it is drained.
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.- The first step of the process is an anaerobicHypoxia (environmental)Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
settling tank. This closed anaerobic tank serves as a pre-treatment to allow solids to fall out of suspension and precipitate to the bottom of the reactor to reduce the turbidityTurbidityTurbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....
of the water. A variety of anaerobicAnaerobic organismAn anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It could possibly react negatively and may even die if oxygen is present...
bacteria are present in this tank; they generate acids and ferment methane. This step may be unnecessary if the influent has low levels of solids.
- Next, the sewage flows through a biofilterBiofilterBiofiltration is a pollution control technique using living material to capture and biologically degrade process pollutants. Common uses include processing waste water, capturing harmful chemicals or silt from surface runoff, and microbiotic oxidation of contaminants in air...
of bark and humic materials. This gives the influent its first filtration and reduces the odors prevalent in anaerobic conditions.
- The mixture then moves into a series of aerobic tanks. The first tank is a dark, closed-top aerobic reactor that serves as a transitional step. The next tank is an open-top, aerobic reactor that contains photosynthetic algaeAlgaeAlgae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
that fix oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
back into the formerly anoxicHypoxia (environmental)Hypoxia, or oxygen depletion, is a phenomenon that occurs in aquatic environments as dissolved oxygen becomes reduced in concentration to a point where it becomes detrimental to aquatic organisms living in the system...
, turbid water. This provides oxygenOxygenOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
and organic food (dead algae) for biological metabolismMetabolismMetabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
and respirationRespiration (physiology)'In physiology, respiration is defined as the transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction...
. Microbial communities proliferateCell growthThe term cell growth is used in the contexts of cell development and cell division . When used in the context of cell division, it refers to growth of cell populations, where one cell grows and divides to produce two "daughter cells"...
, and eventually must consume all of the photosynthetic algae so that the algae do not choke out macrophytes in later steps.
- Many types of bacteriaBacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
immobilize pollutant minerals, but certain speciesSpeciesIn biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of bacteria are crucial to nutrientNutrientA nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
conversion. Specifically, NitrosomonasNitrosomonasNitrosomonas is a genus comprising rod shaped chemoautotrophic bacteria.This rare bacteria oxidizes ammonia into nitrite as a metabolic process. Nitrosomonas are useful in treatment of industrial and sewage waste and in the process of bioremediation. They are important in the nitrogen cycle by...
and NitrobacterNitrobacterNitrobacter is genus of mostly rod-shaped, gram-negative, and chemoautotrophic bacteria.Nitrobacter plays an important role in the nitrogen cycle by oxidizing nitrite into nitrate in soil...
work in steps to nitrifyNitrificationNitrification is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates. Degradation of ammonia to nitrite is usually the rate limiting step of nitrification. Nitrification is an important step in the nitrogen cycle in soil...
ammoniaAmmoniaAmmonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, making it into nitrates, which are available for plant and microbial uptake. These bacteria need calcium carbonateCalcium carbonateCalcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
to catalyze this reaction, so managers must maintain sufficient calcium levels in the water. Denitrifying bacteria such as Pseudomonas fluorescensPseudomonas fluorescensPseudomonas fluorescens is a common Gram-negative, rod-shaped bacterium. It belongs to the Pseudomonas genus; 16S rRNA analysis has placed P. fluorescens in the P. fluorescens group within the genus, to which it lends its name....
convert nitrates into gaseous nitrogenNitrogenNitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
, which is volatilizedVolatilisationVolatilization is the process whereby a dissolved sample is vaporised. In atomic spectroscopy this is usually a two step process. The analyte is turned into small droplets in a nebuliser which are entrained in a gas flow which is in turn volatilised in a high temperature flame in the case of AAS or...
in these open aerobic tanks. Denitrification is the most desirable sink for nitrogen in living machines. Protozoa have been shown to be capable of coliform and pathogenPathogenA pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
suppression. Microbial breakdown is the primary biological treatment of both the conventional activated sludgeActivated sludgeActivated sludge is a process for treating sewage and industrial wastewaters using air and a biological floc composed of bacteria and protozoans.-Purpose:...
process as well as these aquatic ecosystem sludge reactors.
- Higher plants are grown hydroponically in the aerobic tanks and provide multiple services. The most common plant used is water hyacinthWater hyacinthThe seven species of water hyacinth comprise the genus Eichhornia. Water hyacinth are a free-floating perennial aquatic plant native to tropical and sub-tropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 meter in...
(Eicchornia crassipies), which has filamentous aquatic roots with a high specific area. These feather-like roots provide a stable habitat for microbes, and over time a bacterial biofilmBiofilmA biofilm is an aggregate of microorganisms in which cells adhere to each other on a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance...
builds up around the roots. Water hyacinth, bulrush and other macrophytes sequester heavy metals. The bodies of these plants can be harvested and burned, and the heavy metals can be chemically isolated to take them out of the environment. Brassica juncea growing in waste streams has been found to contain up to 10% of its dry weight in lead.
- PlanktonPlanktonPlankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
carries out multiple functions in the system with varying efficacy. Zooplankton feed on extremely small (<25 µm) particles. In juvenile stages they feed on particles smaller than 1 µm. Conventional waste treatment cannot process these fine suspended solids. Although zooplanktonZooplanktonZooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
do consume these fine particles, which are difficult for conventional treatment systems to process, the placement of planktonPlanktonPlankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
in the system is more valuable as a trophic link. Plankton can eat microbes, which are abundant in the system, and the planktonPlanktonPlankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
is an ideal food for filter feeding fish and mollusks. This food chain transfers biomass to higher trophic levels and increases the diversity and complexity of the ecosystem. John Todd thinks that “Since zooplanktonZooplanktonZooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
can exchange the volume of a natural body of water several times per day it is difficult to overstate their importance in ecological engineeringEcological engineeringEcological engineering is an emerging study of integrating ecology and engineering, concerned with the design, monitoring and construction of ecosystems...
.”
- According to Björn Guterstam, another one of the most well-published and experienced ecological engineersEcological engineeringEcological engineering is an emerging study of integrating ecology and engineering, concerned with the design, monitoring and construction of ecosystems...
, this theoretical role has not been as successful in practice. He concedes that phytoplanktonPhytoplanktonPhytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
populations have been limited by toxic and somewhat deoxidized water at the bottom of tanks, as well as light limitations. PhytoplanktonPhytoplanktonPhytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
are primary producersPrimary production400px|thumb|Global oceanic and terrestrial photoautotroph abundance, from September [[1997]] to August 2000. As an estimate of autotroph biomass, it is only a rough indicator of primary production potential, and not an actual estimate of it...
, which provide food for larger zooplanktonZooplanktonZooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
species, so the zooplanktonZooplanktonZooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
population drops with its photosynthetic counterpart. Because these principles have been implemented only on a small scale, these systems have a lowered buffering capacity due to issues of scale and separation from the macroecosystem, even though genetic and functional diversity is encouraged.
- AquacultureAquacultureAquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
can take place in more dilute tanks downstream after the eutrophicationEutrophicationEutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
-causing contaminants have been ameliorated. Snails slide along the tank walls and graze on slime and sludge buildup, cleaning the tank. This self-regulation improves light penetration, which stimulates photosynthetic forms of algae, bacteria and plankton. Filter feeders sift through large volumes of water each day and consume the bacteria and plankton that are small enough to pass through. Mollusks such as mussels and snails, as well as some fish, are filter feeders. DetritusDetritusDetritus is a biological term used to describe dead or waste organic material.Detritus may also refer to:* Detritus , a geological term used to describe the particles of rock produced by weathering...
-feeding fish consume larger particles of suspended biosolids. Herbivorous fish are excluded from tanks where macrophytes carry out useful functions (such as biofilmBiofilmA biofilm is an aggregate of microorganisms in which cells adhere to each other on a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance...
hosting), but when plants are eventually harvested from the system, this plant tissue can be fed to a tank of herbivorous fish for aquaculture production.
- A single AnodontaAnodontaAnodonta is a genus of medium-sized to large freshwater mussels, aquatic bivalve molluscs in the family Unionidae.-Species:Species in this genus include:* Duck mussel, Anodonta anatina Linné, 1758* Anodonta beringiana Middendorff, 1851...
freshwater clam can filter as much as 40 litres/day of water, absorbing colloidColloidA colloid is a substance microscopically dispersed evenly throughout another substance.A colloidal system consists of two separate phases: a dispersed phase and a continuous phase . A colloidal system may be solid, liquid, or gaseous.Many familiar substances are colloids, as shown in the chart below...
al materials and other suspended solids at a removal rate of 99.5%. Many freshwater clams are in danger of extinctionExtinctionIn biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
, in part because some have gills that perform poorly in polluted environments. Since some of these clams can sequester colloids from streams or lakes, this provides an ecosystem service by slowing the erosion of soil colloids. Humans can strike up a symbiotic relationship with the clam genera Unlo and AnodontaAnodontaAnodonta is a genus of medium-sized to large freshwater mussels, aquatic bivalve molluscs in the family Unionidae.-Species:Species in this genus include:* Duck mussel, Anodonta anatina Linné, 1758* Anodonta beringiana Middendorff, 1851...
by providing a clean habitat (when the water reaches the clam tank it is cleaner than some of their wild habitats). In exchange for a good home, the clams could aid humans by filtering colloids and suspended solids out of our wastewater. It is yet to be determined if the clams break up these colloids at all or if it is feasible to recycle clam compost back into field (which increases cation exchange capacity—-an agricultural benefit). Ecological engineering supports symbiotic relations between different species to serve the needs of humans as well as promoting the health of the ecosystem.
Future horizons
In a 2000 report to the USEPA on a South Burlington, Vermont, living machine, Ocean Arks InternationalOcean Arks International
Ocean Arks was founded in 1981 by John Todd and Nancy Jack Todd in the United States.It is a non-profit research and education organization dedicated to the creation and dissemination of the thinking and the technologies fundamental to a sustainable future...
outlined five key areas which could shape the future of this field.
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.
Trophic management
Trophic level
The trophic level of an organism is the position it occupies in a food chain. The word trophic derives from the Greek τροφή referring to food or feeding. A food chain represents a succession of organisms that eat another organism and are, in turn, eaten themselves. The number of steps an organism...
is used to influence entire systems by selective predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
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.
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
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, tomatoes, lettuce
Lettuce
Lettuce is a temperate annual or biennial plant of the daisy family Asteraceae. It is most often grown as a leaf vegetable. It is eaten either raw, notably in salads, sandwiches, hamburgers, tacos, and many other dishes, or cooked, as in Chinese cuisine in which the stem becomes just as important...
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. 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
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, it seems reasonable that ecologically engineered
Ecological engineering
Ecological engineering is an emerging study of integrating ecology and engineering, concerned with the design, monitoring and construction of ecosystems...
wastewater treatment
Wastewater Treatment
Wastewater treatment may refer to:* Sewage treatment* Industrial 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.
List of Living Machines
- 2010-Port of Portland (Oregon)Port of Portland (Oregon)The Port of Portland is the port district responsible for overseeing Portland International Airport, general aviation, and marine activities in the Portland, Oregon metropolitan area in the United States....
headquarters, http://www.portofportland.com. - 2009-Furman UniversityFurman UniversityFurman University is a selective, private, coeducational, liberal arts college in Greenville, South Carolina, United States. Furman is one of the oldest, and more selective private institutions in South Carolina...
, Greenville, S.C. - 2009-Old Trail SchoolOld Trail SchoolOld Trail School is an independent coeducational day school, serving toddler though grade 8, founded in 1920. It is located in Bath, Ohio, in Cuyahoga Valley National Park...
, Bath, Ohio - 2007-Vive Verde EcoCentre, Lake Worth, Fla.
- 2007-Esalen InstituteEsalen InstituteEsalen Institute is a residential community and retreat in Big Sur, California, which focuses upon humanistic alternative education. Esalen is a nonprofit organization devoted to activites such as meditation, massage, Gestalt, yoga, psychology, ecology, and spirituality...
, Big Sur, Calif. - 2007-Northern Guilford Middle SchoolNorthern Guilford Middle SchoolNorthern Guilford Middle School is a government-owned secondary school in Greensboro, North Carolina, teaching sixth through eighth grades. There is an average class size of 26.-Faculty:...
, Guilford County Public Schools, Greensboro, N.C. - 2002-El Monte Sagrado Resort, Taos, N.M.
- Missouri Department of ConservationMissouri Department of ConservationThe Missouri Department of Conservation and the Missouri Conservation Commission were created by Article IV Sections 40-42 of the Missouri Constitution, which were adopted by the voters of the state in 1936 as Amendment 4 to the constitution...
- Anita Gorman Discovery Center, Kansas City, Mo., http://mdc.mo.gov/areas/kcmetro/discovery/info/ - Oberlin CollegeOberlin CollegeOberlin College is a private liberal arts college in Oberlin, Ohio, noteworthy for having been the first American institution of higher learning to regularly admit female and black students. Connected to the college is the Oberlin Conservatory of Music, the oldest continuously operating...
, Ohio http://www.oberlin.edu/ajlc/systems_lm_4.html.
- Berea CollegeBerea CollegeBerea College is a liberal arts work college in Berea, Kentucky , founded in 1855. Current full-time enrollment is 1,514 students...
, Kentucky http://www.berea.edu/sens/ecovillage/ecomachine/default.asp - South Burlington, VermontSouth Burlington, Vermont-Economy:CommutAir, a regional airline, is headquartered in the city, by the airport. The Magic Hat Brewing Company, one of the United States's larger craft breweries, is located here.One measure of economic activity is retail sales...
- Islandwood Education Center - Bainbridge Island, WA: http://www.islandwood.org/default.php
- Arcata Marsh, California
- see Living Designs Group, http://www.livingdesignsgroup.com/eng-project-master-list/
- BedZEDBedZEDBeddington Zero Energy Development is an environmentally friendly housing development in Hackbridge, London, England. It is in the London Borough of Sutton. It was designed by the architect Bill Dunster to support a more sustainable lifestyle...
, Sutton, London, England (not operating currently) - FindhornFindhornFindhorn is a village in Moray, Scotland. It is located on the eastern shore of Findhorn Bay and immediately south of the Moray Firth. Findhorn is 3 miles northwest of Kinloss, and about 5 miles by road from Forres....
, Scotland - Corkscrew Swamp Sanctuary, Naples, Florida (http://corkscrew.audubon.org/Information/LivingMachine.html)
- Clatsop Community College - MERTS site, Astoria, Oregon http://www.clatsopcollege.com/livingmachine
- Ohio State UniversityOhio State UniversityThe Ohio State University, commonly referred to as Ohio State, is a public research university located in Columbus, Ohio. It was originally founded in 1870 as a land-grant university and is currently the third largest university campus in the United States...
, Columbus, OH - Dairy Wastewater Treatment - Harbor Park (Budapest, Hungary)
- PAWS, Inc., Muncie, Indiana
- Conserve SchoolConserve SchoolConserve School is a semester school for environmentally and outdoor minded high school students located in Land O' Lakes, Vilas County, Wisconsin, United States...
, Land O' Lakes, Wisconsin - Darrow SchoolDarrow SchoolDarrow School is an Independent co-educational high school. Its New Lebanon campus is a property in the Berkshire Hills, which are a southern extension of the Green Mountains of Vermont.-History:...
- New Lebanon, NY (http://www.darrowschool.org/page.cfm?p=34) - EVA LanxmeerEVA LanxmeerEVA lanxmeer is the name of a éco-quartier build from 1994 to 2009 in the Dutch town of Culemborg in Nederland.It is an environmentally-friendly-housing development....
- Coevorden, Netherlands (http://www.eva-lanxmeer.nl/docs/bebouwing.html) - Sharon I-89 Northbound Rest Area - Sharon, Vermont
- Julian Woods Community- http://directory.ic.org/619/Julian_Woods_Community
See also
- BioremediationBioremediationBioremediation is the use of microorganism metabolism to remove pollutants. Technologies can be generally classified as in situ or ex situ. In situ bioremediation involves treating the contaminated material at the site, while ex situ involves the removal of the contaminated material to be treated...
- Rain gardenRain gardenA rain garden is a planted depression that allows rainwater runoff from impervious urban areas like roofs, driveways, walkways, parking lots, and compacted lawn areas the opportunity to be absorbed...
- Anaerobic digestionAnaerobic digestionAnaerobic digestion is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen. It is used for industrial or domestic purposes to manage waste and/or to release energy....
- Constructed wetlands
- BiomimicryBiomimicryBiomimicry or biomimetics is the examination of nature, its models, systems, processes, and elements to emulate or take inspiration from in order to solve human problems. The term biomimicry and biomimetics come from the Greek words bios, meaning life, and mimesis, meaning to imitate...
External links
- Living Machine, L3C website
- Living Machines article
- Solar Aquatics Systems, the original Living Machine with transparent tanks
- Interview with Nancy Todd, "Living Machines use waste water, sunlight, plants, and fish to produce abundant fresh food", In Context, Fall 1995
- "Putting human waste back in its place: at the bottom of the food chain", In Context, 1993