Algae Bioreactor
What is it?
The Shed employs natural solutions to close loops and turn waste into useful outputs. The Algae Bioreactor uses excess nutrients from the Aquaponic Module and Vermicomposter to fix carbon dioxide in algae.
Returning this algal biomass to the Vermicomposter adds carbon to the compost in the form of a garden biofertilizer.
It therefore creates a recycling loop that ultimately builds up carbon from the atmosphere in vermicompost and soil. Perched atop the Algae Bioreactor are cover plants, like grasses and meadow flowers, that similarly use Shed nutrients to channel carbon from the atmosphere to the soil.
How does it work?
The Algae Bioreactor harnesses the power of algae to grow biomass. Algae are well-suited to this task being faster-growing and more productive than land plants. The Shed’s Bioreactor grows filamentous algae – a colonial kind of algae better known as pond scum – rather than the single-celled “floating” varieties that live suspended in water. Filamentous algae are all around us in ponds, lakes and rivers, are nearly indestructible and quickly create thick mats of biomass.
For these reasons, they are widely used as “scrubbers” to remove nutrients from aquarium water with hobbyists and citizen scientists leading their development. At larger scales, these kinds of systems have proven capable of effectively cleaning water in sewage treatment plants. Using algae to fix carbon leverages a biochemical process we all know: Photosynthesis. Algae grow in a thin-film of nutrient-rich water that is routed from other parts of the Shed.
They absorb carbon dioxide from the atmosphere along with sunlight and nutrients to build tissues. When this tissue is harvested by scraping to the Vermicomposter, a portion of the original carbon remains in the compost for long periods of time as soil organic carbon. In this way, an important global carbon store – the soil – can be partially replenished by the activities of the Shed. It is a small but meaningful solution to climate change. Meanwhile, the other nutrients stored in the composted algae become available to plants, and have been shown to spur plant growth as effectively as synthetic fertilizers.
Why is it important?
Living and growing food in the future calls for the creative use and reuse of new resources. Algae-based technologies are at this frontier of sustainability. Bioreactors, for instance, have attracted intense interest for an incredibly wide range of uses, such as: Growing biofuels, making sustainable feeds for animals, isolating nutritional compounds from microalgae, scrubbing CO2 from industrial gases and purifying different types of wastewater.
Seaweeds – large forms of algae – have been touted as sustainable foods. Importantly, these and other algae are also poised to help to sequester large amounts of atmospheric carbon to offset greenhouse gas emissions in the future. What ties most of these uses together is that they are innovative ways of “closing the loop” and turning the wastes of humankind into material and economic opportunities.
While humble algae have yet to be fully integrated into to farming on land, it is a powerful ally to watch in the quest for sustainability.
What Sustainable Development Goals (SDG) are met?
The Shed’s Algae Bioreactor contributes to UN Sustainable Development Goals of Quality Education (SDG 4) by fostering skills and knowledge for sustainable living.
The Shed’s Algae Bioreactor contributes to UN Sustainable Development Goals of Industry, Innovation & Infrastructure (SDG 9) by developing clean agricultural technologies.
The Shed’s Algae Bioreactor contributes to UN Sustainable Development Goals of Climate Action (SDG 13) by promoting climate-resilient growing methods.
What can you do?
Visit and study a pond in your neighbourhood to understand the important role of algae in ecosystems.
Learn more about how the Shed’s Algae Bioreactor works with this downloadable lesson plan example which can be done at the Food Shed.
Visit and study a pond in your neighbourhood to understand the important role of algae in ecosystems.
- What are algae?.
- A review of advances and opportunities for algae-based technologies.
- An introduction to carbon gardening.