The only smell from this sewage treatment is that of water within a greenhouse and the fragrance of flowering plants.
by Ryan Durand
The sound of running water fills the air, its bubbling and gurgling permeating the otherwise quiet surroundings. Brilliant green water hyacinths gently rock in the wake of the flowing water, and a thick mat of duckweed moves in the slow circles of the currents' eddies.
Bubbles of air rise in places, displacing the floating vegetation and forming patches of open water where a thick entanglement of willow roots can be seen below the water's surface.
The water that slowly percolates through this tangled web of greenery is teeming with life of all shapes and sizes.
Snails proliferate on the abundant supplies of algae, and countless species of microscopic organisms inhabit the water, concentrated in regions around the plants' roots. At night the relentless sound of the flowing water is broken by the reverberating croaks of frogs, and by day ladybugs and other insects fill the clean, fresh air.
This is the setting in which the sewage of 46 households is treated; the atmosphere in which facility operator Steve Chomolok spends only one hour per day maintaining the system. The water is some 30,000 litres of human sewage per day, flowing through a series of large ponds and wetlands. Each pond is home to a variety of aquatic plants such as water hyacinths, parrots feather, willow and rushes. And yes, the only smell is that of water enclosed within a greenhouse and the occasional fragrance of flowering plants.
Located near the small town of Errington BC, this ecologically designed waste water treatment system is the first of its kind in BC. Designed by Eco-Tek of Vancouver, the system (known as either solar aquatics or a living machine) is a revolutionary process that combines the energy of the sun and the natural functions of plants and animals to purify human waste. These solar aquatic systems are changing the way we humans regard our waste. For centuries, we have considered our excrement to be a useless substance that is an expensive problem to deal with. Now, with the use of solar aquatic systems, we are beginning to change this paradigm.
In natural systems every material is continually recycled and reused. Animal waste, like that of humans, is no exception. Yet our society discards the massive amount of energy and nutrients that is contained within our own wastes without thought. In fact, we routinely use huge quantities of energy and resources to reduce our waste to a "safe" purified form. In doing this we are breaking a natural cycle that has sustained our planet since the time of its creation.
A walk through most conventional waste water treatment facilities is not a pleasant experience. Besides the horrific smell, the constant drone of pumps and other such mechanics is quite appalling. In these huge artificial environments, waste water is repeatedly treated with chlorine and chlorine by-products. When residual chlorine from disinfection reacts with organic matter, carcinogenic by-products like tri-halomethanes and haloacetic acids can form. After the waste water has travelled through the cold steel tanks and been doused with chemical after chemical, it has been transformed into a sterile chemical equivalent of water, but is it really water any more?
In addition to creating carcinogenic compounds, conventional systems produce a massive amount of sludge. In the United States alone, some ten million tons of sludge is produced every year. This sludge is often so toxic that it must be incinerated or trucked off to a landfill for future generations to deal with. The cycle of reuse and recycle is broken, and the nutrients that the waste water contained are not returned to the Earth.
In stark contrast, solar aquatics works on one basic principle: "One organism's waste is another organism's food" (Dr. John Todd, 1998). The nutrients contained within waste water that travels through a solar aquatic system eventually re-enter the cycle of reuse and recycle.
The system is relatively simple. Aquatic plants are grown in a series of large ponds and constructed wetlands. Each tank in the line is openly connected to the next, with water flowing by gravity slowly through the system but allowing plant and animal life to move back and forth freely (Cam Purdy, 1996). waste water flows through the series of ponds, into the wetlands, and is discharged as clean, biologically rich water. The process is based on the natural life cycles and actions of microscopic organisms that inhabit the ponds by the millions.
The microorganisms inhabit the oxygen-enriched area around the plant roots where little bits and pieces of waste accumulate as it flows through the ponds. The microbes happily dine on the waste and, among many other things, convert ammonia (a form of nitrogen) into nitrates. This is particularly important because of the many forms of nitrogen that exist, it is the nitrates that plants require for growth. This symbiotic association between plant and microbe forms a very resilient and adaptable relationship that is the basis of a solar aquatic system.
Bruce Strong of Ecological Engineering Associates (1996) describes how the system is "engineered" to replicate natural food chains:
Plants and animals are introduced into the system as a way of removing the bacteria from the water. The plants absorb the waste (after microbes have transformed the waste into a usable form) and produce sludge, which is eaten by snails. The snails are eaten by fish further down the line.
Constructed wetlands are used as the final stage in the system to "polish" the water by slowly passing it through gravel beds that are planted with reeds, rushes, and other plants. These plants help to remove any nutrients, such as nitrogen and phosphorous, that remain in the water, and provide additional habitat for microbes. Aerobic microbes that inhabit the wetlands uptake any excess nitrates from the water and convert them into gaseous nitrogen, thereby completing the natural nitrogen cycle. The cycle of reuse and recycle is continued, and the nutrients of our wastes re-enter the nutrient cycles of the planet.
The result of this process is a bunch of happy, well-fed animals, healthy plants, and clean water. The treated water is quite safe as "most pathogens are ingested by higher organisms or killed by antibiotic releases from plant roots." (Bruce Strong, 1996). It is the very nature of pathogens, and the majority of microbes that inhabit the human alimentary tract, that leads to their demise in a solar aquatic system. Microbiologist Judy Kandel (1985) explains that "[pathogens] are poorly adapted for growth outside the [human] body, especially when confronted by a vast number of microbes that are perfectly suited for exploiting the rich resources in sewage. Those harmless microbes will quickly prevail at the expense of the pathogens."
In fact, the effluent of some specially designed systems is so clean that it can, and often is, re-used for such applications as flushing toilets or for irrigation. Before the water is re-used, it is often treated with ultra-violet radiation to kill any pathogens that may remain.
The apparatus for these living machines includes:
Solar aquatics are not limited to just the treatment of human waste. From the treatment of cosmetic manufacturing by-products to the revitalization of heavily polluted ponds, solar aquatic systems are used throughout the world for a variety of applications. Systems range in size from single household units that treat several hundred litres per day, to giant commercial facilities that treat upwards of a million litres per day.
Some demonstration systems, built by Dr. John Todd, have even proven successful in treating pulp and paper sludge and petroleum hydrocarbons. Dr Todd (1994) describes how solar aquatic systems can be used to naturally treat pulp and paper by-products.
Within this ecological digester microbial life attached itself to the pulp wastes, forming a heavy, gooey sludge thereby preconditioned for the animals of the system. Toxic substances were also processed by photosynthetic organisms which, in turn, were sustained by dissolved organic matter made soluble by the bacteria. Animal filter feeders and detritus eaters passed the pulp mill sludge back and forth through their guts and intestines, exposing it to digestive enzymes and the complex assemblages of bacteria living there. The original waste material was digested and transformed into a range of by-products, some of which were useful.
Solar aquatics have a comparable price tag in comparison to conventional waste water treatment systems. In situations where a complete sewage system must be built, solar aquatics can offer substantial saving. With their flexible design, solar aquatic systems can be seamlessly integrated into existing infrastructure or built in areas where space is limited and the cost of constructing lengthy collection systems is high. Solar aquatics systems also have an advantage over large constructed wetlands in that they provide total treatment, from primary to tertiary treatment, and they do so in a very small space.
Solar aquatic systems can also be used to grow economically valuable by-products. Some systems are used to grow hydroponic tree and shrub seedlings, bait fish, cut flowers, and valuable specimen plants like orchids and lilies. Therefore, solar aquatic systems not only naturally purify waste water, but they can create a steady revenue to help offset operation costs.
In our new age of technological wonders, it is hard to imagine that one of the most difficult problems of our society, the treatment of our own wastes, can be solved with the use of plants and animals. Dr. John Todd (1995) describes an encounter with a solar aquatic system:
People accustomed to seeing mechanical moving parts, to experiencing the noise or exhaust of internal combustion engines or the silent geometry of electronic devices, often have difficulty imagining [solar aquatics]… Complex life forms, housed within strange light-receptive structures, are at once familiar and bizarre. They are both garden and machine. They are alive yet framed and contained in vessels built of novel materials.
Solar aquatics offer the first true environmentally friendly method of treating human sewage. A method that uses little power and zero chemicals. A method that returns our wastes into the natural biological and geological cycles of this planet, and for the first time considers our wastes not as a horrible problem that must be dealt with, but as liquid energy to be used in a productive manner.
* To learn more about existing systems that are in use around the world, contact Living Technologies at: www.livingmachines.com
* Reference: Nancy Jack Todd and John Todd, From Eco-cities to Living Machines: Principles of Ecological Design, North Atlantic Books, 1994.
[From WS August/September 2000]