Key Elements of OASIS
Technical Elements:
Rainwater Catchment
An important feature for two reasons. First, while an aquaponics system can be up to 95% water efficient, it still requires water; so, why not get it straight from the source? Second, rainwater catchment systems can help fix a serious problem in Canada – in heavy rainstorms, rainwater overwhelms the system, and sewage water is released untreated into our rivers and lakes, bypassing the treatment centers. In 2015, for example, More than 205 billion liters of raw sewage and untreated waste water spewed into Canada’s rivers and oceans.
Aquaponics
A semi-closed system in which plants and fish live in a symbiotic relationship. The system combines aquaculture (fish farming) and hydroponics (growing plants in water). In the circulation system, the nutritious water from the fish is circulated through a series of pipes where the plants absorb the nutrients and the water is returned clean to the tanks for the fish.
Why Aquaponics?
- Easy to Operate and Maintain: a well-designed system is a balanced ecosystem
- Water Efficient: Aquaponics uses just 10% of the water needed for conventional agriculture, and is more water efficient that hydroponics too!
- No pesticides, herbicides, or fertilizers: this not only saves money, but also protects the environment from further imbalances to the nitrogen cycle and other chemicals contributing to climate change and soil degradation.
- Mimics natural cycles: Aquaponics taps into the symbiosis of plants and fish in the natural world. Although fish are living in a tank, they are being raised in simulated river, where their waste products are swept away and replaced with clean water.
- Clean fish: Oceana Canada’s 2018 Fishery Audit tells us that only 1/3 of Canada’s fishery are healthy, and they continue to decline. In heavy decline due to overfishing and temperature changes, fish are found with increasing levels of plastic and toxins. OASIS’s aquaponics not only provides healthy fish for consumption at affordable rates but can also contribute to healthy fish re-population in our rivers and lakes.
Indoor Mushroom Growing
- OASIS envisions an indoor mushroom farm that could be housed in a basement, or in a modified shipping container.
- Mushrooms can be grown indoors with low light, and with the ethos of an integrated food hub, as they “complete a cycle of decomposition and regrowth, breaking down agricultural waste products, and producing both food and high-quality compost”. The carbon dioxide gas exhaled by growing mushrooms can be used as an input to increase CO2 levels for the aquaponics space.
- Mushrooms require cold storage and have a relatively short shelf life, making them the ideal crop to grow locally.
- Mushroom farming can be highly profitable, going from $3-4 per pound for basic white varieties, to $32 per pound for speciality varieties such as oyster or shiitake. Kendal Hills Farm, near Clarington, ON (east of Toronto), sells shitakke mushrooms for $14/lb and varieties of oyster mushrooms for $18/lb to high-end customers such as farmers markets and restaurants as of fall 2018.
Sustainable and Back-up power
As Toronto faces more extreme weather events that impact the City’s energy grid, backup power for indoor food production becomes a component of climate adaptive agriculture.
For example, a Toronto Hydro study shows heat waves and ice storms pose the greatest risk to the electrical grid, and could cause localized power outages that last up to a week. In a power outage caused by extreme weather, backup power allows food production to continue when the food system is most stressed due to the closing of food retailers.
On-site Vermi-composting
Through decomposition of food waste generated by tenants and guests, organic waste is diverted from landfills and processed into a shelf-stable product.
- Diverted from landfills: reduces the load on the municipal system, and removes environmental costs of transportation
- On average, a Canadian produces 170 kg of food waste per year, out of a total of 396 kg food waste per capita when including losses in pre-harvest, processing and distribution. Although composting does not address the root causes of food waste, it reduces the impact on landfills, reduces the output of greenhouse gases due to anaerobic breakdown in landfills, and provides a vector to reuse the materials.
- Product for Sale: premium compost, further enriched with worm castings, can be sold as a product at the food hub and local garden shops.
Food Storage
- Storage of dry goods including grains, pasta and canned goods, as well as root vegetables. OASIS envisions the unused basement space of high-rise apartment blocks serving as storage space. This space serves the dual purpose of storage for goods sold in the storefront, as well as longer term storage of food reserves.
- As our food supply chains are impacted by extreme weather events, a food and water reserve situated locally and serving the community is an essential component of climate adaptation.