Living machine

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LIVING MACHINE

ECOLOGICAL WASTEWATER TREATMENT

INTRODUCTIONLiving machine is a trademark and brand name for a patented form of ecological sewage treatment designed to mimic the cleansing functions of wetlandsThe technology is based on fixed-film ecology and the ecological processes of a natural tidal wetland, one of natures most productive ecosystems.

HISTORYDr. John ToddThe initial development of the technology in the United States is credited to Dr. John Todd, the internationally renowned ecological designer, developed at the now-defunct New Alchemy Institute. The Living Machine system falls within the emerging discipline of ecological engineering.

The world's most beautiful wastewater treatment plant :Omega Center for Sustainable Living

Size V/S Energy ComparisonOn-Site Wastewater treatment

Mineral diversityNutrient reservoirsSteep gradientsHigh exchange ratesPeriodic and random pulsesCellular design and mesocosm structureSubecosystemsMicrobial communitiesPhotosynthetic basesAnimal diversityBiological exchanges beyond the mesocosmMesocosm/macrocosm relationshipsTwelve Precepts of Ecological Design

Biological richness of the earth is a result of the complexity and diversity of its mineral foundations.In mineral-rich zones, life can be extraordinarily abundant.In designing living machines, mineral diversity should include igneous, sedimentary and metamorphic rocks.In living machines they use finely ground rock powders which are quickly incorporated into biological systems.In one experiment they have digested 19000 m3 of bottom sediments in a polluted 4 ha pond with the application of 7200 kg of rock powders from glacial materials. They were used in combination with a floating living machine through which 750 m3 of pond water circulated daily.1. Mineral diversity

2. Nutrient reservoirs

Mineral diversity provides the long-term foundation for nutrient diversity.Microorganisms and plants require nutrients in an available form if carbon is recalcitrant, or phosphorus in an insoluble state, or the NPK ratios are out of balance, or trace elements are missing, the ecosystems can become impoverished.Ex. If an appropriate inorganic carbon source is not available to the nitrifying bacteria, the degradation of nitrogenous waste products is reduced and toxic levels of ammonia can increase.The flora of waste purification systems can be completely altered by trace mineral imbalances.

3. Steep Gradients

It increase the diversity of internal processes and the multiplicity of pathways within a living machine.Abrupt or rapid change, as measured in time or space, in the basic underlying attributes or properties of the subsystems.For ex. a waste stream can benefit from passing through a series of stages that have different oxygen regimes, redox potentials, pH, temperature, humic and ligand or metal-related state. When the redox is low enough to cause hydrogen sulfide to form, treats polluted lakes with forced aeration, or with the addition of nitrates.The ecological designer should consider using diverse humic materials in various subsystems to produce gradients. Iron compounds are key redox elements in regulating paddy soils and health.

4. High exchange ratesMaximize the surface area of living material to which a waste stream is exposed.The challenge is to create surfaces and associated communities that are not disrupted by strong currents and turbulence yet do not impede flows.One approach is to grow floating aquatic plants on the water surface and, with aeration, to create up wellings that pass large volumes through the root mass and associated biological communities.Surface area of roots available to microorganisms is several order of magnitude greater than that of manufactured substitute surfaces.

Ecological fluidized bedsIt is a technological development a step beyond trickling filters or conventional biofilters used in intensive closed system aquaculture.The medium, whether plastic or of mineral origin, must have a specific gravity approaching 1 so that the medium will be buoyant or capable of being readily re-suspended. Medium should have rough-surfaced or porous.Ecological fluidized beds have rapid internal recycling rates and still provide habitat for diverse benthic animal communities. Such communities can include snails and clams, attached algae, aquatic plants, and higher plants.Nitrification as well as some denitrification can occur within the same internal recycle loop due to the abrupt oxygen gradients and the presence of endogenous organic carbon in the beds

Pumic rock

5. Periodic and random pulsed exchanges"Direct reaction of organisms to environmental change is most useful if the environment is being altered in an unpredictable way... One can say that the ecosystem has "learned" the changes in the environment, so that before it takes place, the ecosystem is prepared for it, as it happens with yearly rhythms. Thus the impact of the change, and the new information are much less"."By creating a pulse, perhaps by controlling the water table or by covering plants with black plastic an introducing new plantings to accelerate the self design, a simpler system with a large net yield may replace the complex one with many low yields".living technologies become robust enough in ecological terms to survive the inevitable failure of some of the system's external hardware and software.

6. Cellular Design is the Structural Model

Can range from three-cell systems to a 20-cell system13

multiple rows of "cells" connected together like beads on a string.

7. Minimum number of subecosystemsAll the ecologically engineered systems they describe have at least two subecosystems.One is an algae growth chamber or algal scrubber that operates under intense light and acts as a control module.Three major components or subsystems. It consists of photosynthetically driven system that is connected to an animal consumer component, which in turn, is connected to a detritus/bacterial system

8. Microbial CommunitiesThat microbial communities are the foundation of living machinesbacteria species have highly specific nutritional and environmental requirementsMany important reactions are catalyzed only by bacteria.In their work with the degradation of coal tar derivatives (PAHs) they inoculated the treatment systems with microbial communities from such diverse locations as salt marshes, sewage plants and rotting railroad ties

Nucleated algae, water molds,slime molds, slime nets and protozoa are organisms with exceptionally diverse life histories and nutritional habits.Protozoan's are important in removing coliform bacteria and pathogens from sewage. They also serve to remove moribund bacteria and improve system efficiencies.

Fungi are key decomposers in ecological systems. It is estimated that there are about 1,00,000 species, many capable of excreting powerful enzymes.They can be as efficient as heterotrophic bacteria in the removal of organic matter from wastewater.Fungi tend to be more dominant in low ph and terrestrial soils than in aquatic environments.It may be that living technologies should incorporate soil-based acid sites linked to the main process cycles into their design.

9. Photosynthetic foundations are essentialEmploying plant diversity can produce living technologies that require less energy, aeration and chemical management.Root zones are superb micro-sites for bacterial communities.Enhanced nitrification in treatment cells covered with pennywort, hydrocotyle umbellata, and water hyacinth, eichhornia crassipes, as cornpared with comparable cells devoid of higher plants.

Pennywort, hydrocotyle umbellataWater hyacinth, eichhornia crassipes

One species of mustard, Brassica juncea, has been found to remove metals from flowing waste streams, accumulating up to 60% of its dry weight as lead.Metals can be recovered from harvested, dried and burned plants. Certain species of higher plants such as Mentha aquatica produce compounds or antibiotics that can kill certain human pathogens.There is economic potential in plants from living machines. Flowers, medical herbs and trees used in rhizofiltration in a waste treatment facility can subsequently be sold as byproducts.

mustard, Brassica junceaMentha aquatica

10. Animal DiversityFind control species, meaning those organisms capable of directing living processes towards such useful end points including foods, fuels, waste recovery, and environmental repair.The potential contributions of animals to living technologies is remarkable.

Snails are central to the functioning of living technologies. Pulmonate snails, including members of the physidae, lymnaeidae and planorbidae families feed on the slime and sludge communities. They thrive in zones where predators are lacking.Snails play a dominant role in sludge reduction, tank maintenance and ecological fluidized bed and marsh cleaning. Snails of the family planorbidae graze and control filamentous algae mats that would otherwise clog and reduce the effectiveness of the diverse fluidized bed communities. Some snails digest recalcitrant compounds.

planorbidae family

Physidae family

The salt marsh periwinkle, littorina irrorata, produces enzymes that attack cellulose, pectin, xylan, bean gum, major polysaccharide classes, algae, fungi and animal tissues as wellAs 19 other enzymes interactive with carbohydrates, lipids and peptides. Snails can function as alarms in the living machines treating sewage. When a toxic load enters the providence sewage treatment system for example the snails quickly leave the water column and move onto the moist lower leaves of the floating plants above the water. Observing this behavior the operator then increases the rate of recycling clean water back upstream into the first cells.littorina irrorata

Virtually all phyla of animals in aquatic environments feed through some filtration mechanism.Bivalves, algivorous fish, zooplankton, protists, rotifers, insect larvae, sponges and others are in this functional category.They remove particles of roughly 0.1 m to 50 m from the water column.

Freshwater sponges, Spongilla

Rotifers

Bivalves are significant filterers.Mussels can retain suspended bacteria smaller than 1 m.Efficiencies reach 100% for particles larger than 4 m. Individual freshwater clams of the genera Unio and Anodonta filter up to 40 l/day of water, extracting colloidal materials and other suspended organic and inorganic particles.Removal rates are 99.5%. In one experiment clams were used in a Russian river to reduce total suspended solid levels of 50 mg/1 to 0.2 mg/l

Duck mussel,Anodonta anatina

Unio pictorum

Freshwater clames

Zooplankton can be employed to good effect in applied mesocosms. They feed upon particles 25 m and smaller. Their nauplii or juvenile stages graze sub m sized particles. Since they can exchange the volume of a natural body of water several times per day it is difficult to overstate their importance in ecological engineering.We have found zooplankton throughout 3m deep ecological fluidized beds comprised of 2 cm sized pumice rock in a prototype living technology that upgrades secondary sewage effluent to reusable quality water in San Francisco.

Zooplankton

chironomid life cycle

facilities chironomid larvaeChironomid adult

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Vertebrates play key roles in the functioning of living technologies. fishes are the most numerous and diverse of the vertebrates.In diet, behavior, habitat and function fish are extraordinarily diverse. Filter and detritus feeding fish are common to all the continents. The filtration rate of algivorous fish may be five orders of magnitude greater than their volume every day. In theory it is possible for the total volume of a fish pond to pass through algae-filtering fish on a daily basis. There are edible fish species like the Central American Characin, Brycon guaternalensis, that are capable of shred- ding and ingesting tough and woody materials.We use members of the South American armored catfish family Plecostomidae to control sludge build up in waste treatment and food culture living technologies.

Brycon guaternalensis

Tilapia, Oreochromis spp., are used to harvest small plants like duckweed and aquatic ferns. The grass carp, Ctenopharyngodon idellus, recycles a variety of plant materials. In several living machines minnows, including the golden shiner, Notemigonus crysoleucas, and fathead minnow, Pimephales promelas, feed on organic debris and rotting aquatic vegetation. They breed among rafted higher plants grown on the surface of the water. Excess minnows are sold as bait fish.

Tilapia, Oreochromis spp

grass carp, Ctenopharyngodon idellus

Notemigonus crysoleucas

fathead minnow, Pimephales promelas

11.Biological exchanges beyond the mesocosmTo optimize their self-design and organization capacities a living technology may require gaseous, nutrient, mineral and biological linkages with larger natural systems. For aquatic mesocosms select organisms from stream, pond and lake environments. Its is valuable to return each season to these same environments for samples. Doing so will provide organisms adapted to seasonal differences. An interesting experiment would entail linking a living machine to a natural ecosystem and exchange biological materials between the two.A sewage treatment facility for could be connected with a nearby marsh or pond. A small percentage of the flow could be directed to the natural system which, in turn, could be linked back to the living technology. natural system would provide, on a periodic or a continuous basis, an inflow of chemical and biological materials. The linkage would allow the natural water body to act as a refugia for the living technology, protecting it from toxic upsets or unnatural loadings.

12. Microcosm, mesocosms, macrocosm relationships The most complete living system of which we are aware, the earth, should be the overriding basis for design. the planet having 70% of the interior space occupied by water and the remainder terrestrial.Use renewable energy Ecological design will help create a symbiotic partnership between humanity and nature.

Design applied: Ocean Arks International has a Solar Aquatic TM living machine for the treatment of sewage.

Avg. HRT: 4.5 days applies when tanks with translus- cent light transmitting sides are used for waste treatment The first treatment room consists of four rows of six translucent tanks plumbed in series. The tanks are rich with microbial and algal communities, and water hyacinths, Eichornia crassipes, provide the dominant surface cover. The first five tanks in each line are mixed and aerated with fine bubble diffusers. The sixth tank is without aeration and functions to settle the solids.Solids are recycled to the first tanks in the series and periodically returned to the adjacent main sewage facility.The supernatant from these tanks flows into a set of engineered "tidal" marshes in the second room.Each treatment line flows into two gravel bed marsh trays.These marshes are planted with wetland species The flow is controlled to fill one marsh for 12 h and then switched to the other marsh, allowing the first to drain and dry.This simulates the wet/dry cycles of a tidal marsh.From the marshes the flow is pumped back up into another series of six translucent tanks. These tanks are stocked with a diverse community of racked and floating tropical and temperate plants. The biofilter is filled with a recycled plastic floating media installed in translucent cylindrical tank. The final marsh is a galvanized steel stock trough filled with gravel and planted to a variety of tropical and temperate wetland species

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Water samples at the Ocean Arks International research facility in Providence, Rhode Island

Flow: 61- 34 m3/dHRT: 2.5-4.5dInfluent COD : 800-100 mg/l

Result & discussion

BOD Removal

COD Removal

Nitrogen removal

Phosphorous Removal

Since Providence is a city with a large electroplating industry metal uptake was a concern in performance evaluation.Cadmium, chromium, copper, silver and zinc were an order of magnitude below the standard levels. The data suggests that living technologies may be a cost effective new way of protecting and improving water supplies. Heavy metals removal

Water hyacinths played only a minor role in metals uptake. No more than 1% of the metals appeared in the plant tissue analysis

One of our design objectives was the removal of most of the coliform bacteria without the need for chlorination or other sterilization procedures. Except for two occasions coliform counts in the effluent were below swimming water standards of 200 counts per 100 ml. The effluent was below 15 coliforms per 100 ml, the standard for food contamination, over 60% of the time. Fecal coliform removal

Raw, untreated sewage in the Baima Canal before Restorer installation havingbad odor & health problems.The Baima Canal after Restorer also functions as a community walking bridge. Urban Municipal Canal Restorer Fuzhou, ChinaCase study

Flowering plants now line the walkway Restorer

second generation living machine

CanclusionProduce beneficial byproducts, such as reuse-quality water, ornamental plants,Flowers,plant productsfor building material, energy biomass, animal feed.Less energy and land requeriment w.r.t. conventional WWT.No chemical are required.It can handle flow variation & seasonal variation.It is sustainable.No production of sludge. The living machine significantly decreased the COD of sewage inputs, as compared to zero-treatment model outputs. The living machine has the potential to effectively remove phosphate, but optimum pH and redox conditions must be maintained.Efficient nitrogen removal by nitrification and dinirtification.

REFERANCEJohn Todd *, Beth Josephson, The design of living technologies for waste treatment, Ecological Engineering 6 (1996) 109-136.

John Todda,b, Erica J.G. Browna,b, Erik Wellsb, Ecological design applied, Ecological Engineering 20 (2003) 421440