Biochar: soil & water remediation, fighting climate change
A relatively little-known substance called ‘biochar’ is beginning to attract a great deal of attention in Canadian and worldwide environmental circles, and it could very well soon become an important element in the green revolution of the 21st century and a key player in the fight against climate change.
Across Canada, recent studies of municipal wastewater have consistently turned up trace amounts of over-the-counter and prescription medications, some of which remain persistent in the environment over long periods of time. Up to 35 per cent of drinking water samples taken across the country and analyzed for a heretofore unpublished study by Health Canada show trace amounts of drugs and their by-products.
Moreover, it is a fact that there is more carbon in the soil than in the atmosphere and all of plant and animal life combined. By returning carbon to the soil on a massive scale, scientists and researchers believe that a solution to climate change exists today right under our feet.
This is where biochar could soon begin playing an important role in soil and water remediation, as well as in the fight against climate change.
Biochar is essentially a form of charcoal made from the partial combustion of organic materials through pyrolysis, which is the direct thermal (at temperatures varying between 500 and 600 degrees Celsius) decomposition of biomass in the absence of oxygen, to obtain an array of solid (biochar), liquid (bio-oil), and gas (syngas) products. Biochar contains high levels of organic carbon and enriches soils by adding nutrients such as potassium and calcium and boosting the soil’s ability to retain water and nutrients.
When large amounts of carbon are introduced into the earth, the soil becomes a more welcoming environment for fungi and bacteria, which boost the amount of nitrogen and other nutrients available to plants. Carbon in the form of biochar remains stable within the soil for thousands of years. Studies show that the addition of biochar improves crop yields, especially in poor soils, which could go a long way to improving agricultural productivity in places where the soil has been degraded as a result of centuries of uninterrupted farming.
Biochar also helps neutralize acidic soils such as those found in the Amazon, where almost fifty years ago the Dutch scientist Wim Sombroek discovered millennia-old patches of dark, carbon rich patches of earth known today as ‘terra preta.’
Preliminary studies of biochar have likewise demonstrated its potential as a charcoal substance that could function as a filter for the removal of traces of pharmaceutical drug residues and hormones from treated wastewater before it is discharged into surrounding bodies of water that are used to provide potable water (and also water that is used for irrigation purposes) for cities and municipalities located downstream from treatment plants.
Using biochar in the fight against climate change
As plants grow, they absorb CO2 and therefore produce biomass that contains carbon. Rather than let unused vegetation decompose while emitting CO2, pyrolysis can transform approximately one half of the carbon into a stable and inactive form. Photosynthesis absorbs CO2 from the atmosphere and biochar retains carbon in a solid state, and can also help to reduce other greenhouse gas emissions (GHGs) such as methane and nitrous oxide (agricultural activities are a significant source of nitrous oxide and methane emissions that contribute to global warming).
Eco-West has begun looking into the potential applications of biochar and is presently in search of opportunities and partners to explore possible initiatives in this emerging field of interest in the fight against climate change.