By Mike Shiralian
Biochar has many applications in helping with climate change, food security, renewable energy and waste management. It is carbon rich charcoal produced through thermal pyrolysis (300oC-700oC) of biomass, under little or zero oxygen conditions. The process also produces a mixture of organic gaseous (syngas) and liquid fraction called “wood vinegar” as byproducts.
Feedstocks to make biochar are abundant and include carbon waste streams from agriculture, forestry, urban sources, farm wastes, livestock remains, human, food and other compostable wastes. These are all low-value materials with limited uses and high disposal costs.
Its tremendous porous and surface structure provides a great habitant for micro-organisms, increases bioavailability, and creates a reservoir for water, nutrients and, in certain applications, pollutants. Using it as a soil additive increases plant growth rates. This, in turn, provides an effective sink for sequestering atmospheric carbon dioxide. Other benefits include:
- Less risk of reduced crop yield during dry seasons;
- Reduce the need for chemical fertilizers containing nitrogen and phosphorus;
- Help retain nitrogen and sulfurs in soil, which also reduces emissions;
- Facilitate reestablishment of vegetation on sterile ground;
- Inhibit the growth of molds or mildews;
- Odour control;
- Filter out contaminants from shallow soil water;
- Remove heavy metals and acids from abandoned mine ponds;
- Bind toxins and prevent their leaching into surface and ground water.
Currently, a variety of biochar derivatives are being produced, with different properties depending on the feedstock, pyrolysis condition, residence time and additives added. Standardization and classification of the various types are required if it is to be marketed for public use.
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Such regulatory initiatives are already underway through many local and international organizations such as the International Biochar Initiative, Biochar Ontario and the Canadian Biochar Initiative. In December 2015, the Canadian federal government approved commercialization of biochar in Alberta, based on a request by the Alberta Biochar Initiative.
Widespread benefits of biochar
Biochar is one of the few climate mitigation and soil enhancement technologies that is relatively inexpensive, widely applicable and quickly scalable. Also, there is a need for small municipalities to recycle their increasing amounts of sewage biosolids and organic wastes in a sustainable way. The technology has advanced so that any municipality could build its own pyrolyzer kiln (or microwave oven) and start converting wastes into biochar.
Mike Shiralian, PhD., is an independent biochar science consultant. This article appears in ES&E Magazine’s June 2016 issue.