Below you can take a virtual tour of sustainability systems designed by Radix’s Scott Kellogg and Stacy Pettigrew, both past and current.
Front Entrance: This is the main entrance to the Rhizome Collective’s former warehouse. When we began in 2000, it was a burnt out shell of a building with an asphalt parking lot in the center. Since the removal of the asphalt, it was changed into a lush, thriving garden. Wood mulch that was otherwise destined for the landfill has been collected for free local tree trimming businesses and spread across the courtyard. Acting like a giant biological sponge, the courtyard’s water retention has been increased, allowing us to maintain a green oasis in the dry, hot Texas summers. An additional benefit of asphalt removal is that the courtyard was noticeably cooler in the summer than it used to be, the heat trapping tar having been replaced with temperature moderating soil and trees.
Rainwater harvesting: We collect rain water off the roof of our shop and store it in a 3000 gallon, polyethylene tank. It is captured through gutters and funneled by pipes into the tank. Although it could be used to drink or wash with, our water is used primarily for gardening and to keep our pond full. Rainwater is far better for plants than municipal water, as it has no chlorine nor any of the other toxic additives found in city water. By collecting rainwater, you ensure your own safe water supply, in case municipal water was ever cut. By using rainwater, communities become self-sufficient, and rely less on the diversion of rivers and upon environmentally destructive dams. Although rainwater harvesting is supported by the city of Austin, it is illegal in some states and countries where water supplies have been privatized. Catching rain as a form of direct action! It is possible to drink rainwater, however, it is necessary to pre-filter it, as pathogens may have proliferated in the water during its storage. Tanks can be made from polyethylene, fiberglass, concrete, stone, or a variety of other materials. Ideally, storage vessels are made from opaque materials in order to inhibit unwanted algae growth. In areas like Austin where it rains infrequently, it’s necessary to have a large water storage capacity to get through the dry periods. Areas that receive year round consistent rainfall can make use of smaller containers. Water storage doesn’t have to be expensive: food-grade 55 gallon barrels can be piped together to make a cheap catchment system, as is shown here in this model. (Note: the piping on this system is not yet complete).
Polyculture pond: Aquatic systems are among nature’s most biologically productive. Large amounts of food, fuel and fertilizer can be produced in a relatively small space, making them ideal for an urban environment. Our polyculture pond is an experimental system where we are cultivating edible water plants (rice, duckweed, water celery) with green manure plants (water hyacinth, azolla), ornamental plants and animal life. Water plants like duckweed and azolla can double their mass every other day under optimal conditions, making them ideal as a food for humans or livestock. The animal life here includes minnows, crawfish, frogs, dragonflies, clams and snails, all of whom play a vital role in the ponds ecosystem. Gambusia minnows and dragonfly larvae are both voracious mosquito predators. Together, the two species make the pond a biological mosquito trap. The pond itself is beautiful and is a wildlife attractant, drawing in wild birds, mammals and reptiles. The pond pictured is made from a galvanized stock tank coated with a fish-safe epoxy. It is joined to a ring of cut-in-half fifty five gallon barrels that serve as cells capable of being closed off to allow sensitive species to grow in isolation.
Constructed wetlands: Constructed wetlands are artificially created systems that mimic natural wetlands’ function of purifying water. In this case, they treat household wastewater, or greywater, which, apart from a few contaminants, is relatively clean and capable of being reused. NOTE: We do not treat toilet water, or blackwater, as it is called. This system consists of several bathtubs filled with gravel, which have water plants growing inside them. Wastewater passing through the aerobic root zones of the plants is cleaned by the bacteria living there. The bacteria consume organic nutrients while the plants themselves uptake nitrogen and phosphorus. By the time it exists the system, the water has been made safe for reuse in irrigating vegetable crops. Plants used in this system include: bulrush, taro, cattail, papyrus, swamp hibiscus, canna lilly and phragmittes reeds.
Vermicomposting: Vermicomposting is using worms to break down food wastes into nutrient rich fertilizers. The worms, called red wigglers (eisenia fetida), convert food scraps into a compost that can be applied directly to soils, or used as inoculants in compost tea mixtures. The worms are put in small plastic boxes that can be kept indoors without producing odors. Able to be stored under a sinks, vermicomposting is ideal for the urban dweller without access to even a small piece of land. All of the digestion in a worm’s gut is done by bacteria, so what it excretes is rich in beneficial microbial life.
Micro livestock: Chickens, turkeys and ducks can be very useful in a sustainable system. Aside from meat, they yield eggs, act as pest control, lawn mowers and soil builders. Being small, they have a much lighter impact on land than larger animals like sheep and cows might, and require much less in terms of space and food. For these reasons, they are perfect for the urban environment. Able to eat compost, they can quickly reduce the volume of food waste and convert it into a usable protein.
Bicycle Windmill: This is a windmill built primarily from recycled bicycle parts. Mounted on a car axle, it can rotate 360 degrees. Windpower generation in Austin is a seasonal operation, with our strongest winds in the winter. It can compliment a solar system on overcast days. Built for under thirty dollars, this windmill is capable of generating low, but useful amounts of electricity for a relatively small investment.
Food Forest: We planted numerous varieties of fruit and nut trees at the Rhizome warehouse, as well as up and down the street. Our trees included: peach, plum, pomegranate, persimmon, pear, fig, jujube, loquat, kumquat, Satsuma orange, Mexican plum, apricot, mulberry, quince, olive, apple, almond, pecan and asian pear. Fruit trees are ideal for cities, as they utilize vertical space. Once established, urban orchards require little care and yield fruit over many years. Fruit trees can be grown in soil of questionable quality as contaminants are less likely to cross the fruit-stem barrier.
Passive solar tech: Passive solar technologies utilize mirrors, glazing and insulation to maximize solar energy for cooking and heating. Unlike active solar technology, or solar panels, passive solar devices have no electronic components. Examples of passive solar technologies include solar ovens, batch collector water heaters, and parabolic cookers, as shown here. In climates with abundant sunshine, passive solar tech can dramatically reduce people’s use of fossil fuels.
Earth building: We have experimented with several natural building techniques. These include strawbale, cob, slip chip ,slip straw and clay based aliz paints. These building techniques create beautiful spaces using primarily clay, sand and straw, an agricultural waste product. The amount of embodied energy that goes into the production of these materials is condiderably less than in concrete, steel, lumber and gypsum. Natural building projects can be held as community events, and result in far less construction waste being generated than in conventional building.
Solar Bioshelter / Aquaculture / Aquaponics: The bioshelter is a solar greenhouse that uses 55 gallon water barrels as a source of thermal mass heating. The greenhouse in south facing to maximize solar gain, and is protected from northern winds by the wall of the warehouse. It is made from a combination of recycled double pane windows and twin-wall polycarbonate. Inside of it, we grow starter vegetables to get a head start on the growing season. Water has amazing properties as a source of thermal mass. Large amounts of energy are required to raise its temperature, and in turn, a large amount of heat is given off as it cools. In this regard, the barrels of water in the green house act as solar batteries. They heat up in the day and release heat in the night or on sunless days when they cool, thus moderating the internal temperature. In the barrels we are raising tilapia fish. Tilapia are an herbivorous fish that are highly efficient at converting protein. They can eat a variety of foods, including duckweed, algae and insects. The wastes from the tilapia are processed through a biological filter, and help to fertilize algae in the tanks, which is eaten by the fish. Edible water plants are grown in a system called aquaponics. In aquaponics, wastes from the fish provide nutrients to plants that are suspended on rafts and have their roots suspended in the water. Plant species that we grow aquaponically include water cress and water spinach. Aquaponics differs from hydroponics , a system that uses synthetic nutrients to grow terrestrial plants in water.
Bioremediation: Apart from gaining access to land, one of the largest obstacles to food production in cities is the high levels of toxins that are present in urban soils. Ranging from heavy metals to pesticides to hydrocarbons, these contaminants can accumulate in plants, and if eaten, can make us sick and weaken our immune systems. Bioremediation is the process of using the natural properties of living organisms to accumulate, bind up, or degrade toxins. We have been researching methods to make bioremediation simple and affordable with the intention of making it accessible to people without backgrounds in science and engineering, and broadly applicable in today’s cities. Areas of bioremediation include mycoremediation (fungi), phytoremediation (plants), and bacterial remediation. We have worked with grass roots organizations in New Orleans to establish a community based bioremediation program to clean up toxins present before, and left behind from hurricane Katrina.
Compost tea: Compost tea is a liquid culture of beneficial microbiological organisms (bacteria, fungi, nematodes and protozoa). It is made by inoculating a container of de-chlorinated water with well-made compost, adding a source of food (molasses, fish hydrolase, humic acid), and aerating the mixture with an air pump for a number of hours. Microbes multiply in the oxygenated water, using the food to fuel their expanding numbers. Teas are applied to damaged soils to restore their microbial populations. Repeated applications of compost tea to contaminated areas will hasten the degradation of certain toxic compounds. Additionally, compost tea can be used as a foliar spray, to treat disease stricken plants.
Biogas: Biogas is the name given to the mixture of methane, carbon dioxide and other gases produced during anaerobic decomposition. Methane, the primary component of natural gas, exists in high percentages in biogas. It can be burned, and used for cooking or heating in a house.
To produce biogas, chopped up water hyacinth (a rapidly growing water plant) is placed in a 5 gallon bucket, and covered with water to create a slurry. A 5 gallon clear water jug with its bottom removed and a valve placed on top is sleeved on the inside of the bucket, creating an air tight seal. As oxygen is used up, anaerobic bacteria become active, and produce biogas through their metabolic processes. The water jug will begin to rise as the gas builds up inside. It can then be stored in bags or inner tubes for later use. The spent slurry can be either composted aerobically or put into an algae tank.
Biofuels: Diesel engines designed at the turn of the century were capable of being run off of vegetable oil. Today’s diesels still have that capacity, but the vegetable oil must be made less viscous. This is accomplished in two ways, by either having it undergo a chemical process, or heating it. Veg oil treated chemically is called biodiesel, and is usable in any diesel engine. Alternatively, oil can be heated by waste heat on the vehicle, made less viscous and be used directly. Currently, our tractor is running off of waste vegetable oil. We don’t consider biofuels to be a solution to the world’s energy problems, but a transitional strategy that utilizes a genuine waste product and is carbon neutral.
Floating Island: The floating island is a raft made from recovered thrown away plastic bottles. It sits in the retention pond on our brownfield site. Its job is to filter the polluted urban stormwater runoff water that fills the pond following a rainstorm. It does this by supporting a variety of water plants that have been zip-tied to its frame. Their roots have colonized its surface and hang freely in the water. Water passing through them is filtered by the variety of organisms that the plant roots provide habitat to. Nutrients are uptaken and exchanged, and toxins degraded. Our plan is to create several more of these islands, and have a significant impact on the quality of the water.