Authored by Luca Barani

Biochar is a natural material obtained by anaerobic burning agricultural and forestry wastes through pyrolysis. Its final formation is composed mainly of carbon but also nitrogen, oxygen, hydrogen, and traces of other materials. In the last few years, biochar has received growing attention from the academic world because of its potential implementation as a climate change mitigation tool. Potentially, biochar may help sequester a billion tons of carbon per year. Its production process is typically carbon negative because it reduces the CO2 in the atmosphere--of course this is dependent on the biomass being sustainably sourced, which is an entirely separate topic. Creating biochar is to convert the unstable gaseous carbon in decaying plant material into a stable form that is stored in the final product. Once it is produced, biochar currently finds its main applications as a soil fertilizer, in water filtration, in construction materials, in animal operations and numerous other uses, which are growing steadily.

Amata Green is a company who works in the world of regenerative agriculture and is helping businesses worldwide learn about sustainable practices as they pertain to food and agriculture.

My name is Luca Barani and as an International Intern with Amata Green, LLC for the Spring 2021 semester, I was tasked with learning more about the topic of biochar and water filtration. On the 22nd of January 2021, I had the opportunity to interview Bryan Eagle, CEO of Glaris, and to ask him some questions about biochar’s application in water treatment and its features. Below is a part of that interview.

Bryan, in your opinion, what makes biochar a valuable alternative in water treatment? What are the main differences between biochar and activated carbon?

Bryan: Biochar at its core it is very similar to activated carbon, but with some differences:

It is generally cheaper to produce than other filtration materials;
Depending on the raw materials used and the cooking temperatures it can remove organic materials as well as heavy metals;
The processes used to produce biochar and regenerate it are typically much greener.

Colleagues experimenting with biochar water filtration. Photo Credit: Robert Tonks

Biochar can reduce water pollution by adsorbing* organic and non-organic pollutants. However, its adsorption capacity highly depends on its composition, the pyrolysis process influences the properties of the final sample. Overall, biochar obtained through low pyrolysis temperatures is more efficient in adsorbing polar compounds (i.e. heavy metals). While high temperatures pyrolysis ensures biochar a strong capacity for attaching organic compounds.

*NOTATION: adsorb means to hold (molecules of a gas or liquid or solute) as a thin film on the outside surface or on internal surfaces within the material. This is different from absorb.

The main difference between biochar and activated carbon is the pyrolysis process through which they are generated:

Biochar is obtained through pyrolysis with lower temperatures (under 450 °C); at these temperatures, the carboxyl groups remain in the final product and, through ion exchanges, enable it to adsorb heavy metals from water;

Activated carbon is achieved by higher temperatures (1000 °C), longer cook times (12+ hours), and it is more efficient in adsorbing organic pollutants.

Experiments with biochar for water filtration. Photo Credit: Robert Tonks

Why is biochar not yet a common product in water treatment or even farming?

Bryan: Overall, the water industry is fairly risk averse. They are scared to switch or innovate methods because if a mistake occurs; then, it will be a matter of public health concern.

Also, the production of biochar is quite a complicated process. First, it is not easy to obtain a final product that can be produced consistently: feedstock and waste materials may vary in characteristics and compositions. Distance usually plays an important role for farmers: farmers may be far from the biochar plant, and transportation costs can significantly alter the cost of production. However, [Bryan has] managed to overcome these issues, and the plant is working on can now count on two billion pounds of raw materials per year. [We] can now produce a very high-quality product facing low costs.

Does the external natural ecosystem interact with the biochar effectiveness of water treatment? Are there any suggested conditions under which biochar would be working more efficiently?

Bryan: Not really. Biochar's adsorbency works over a wide PH range; hence it performs efficiently in most industrial and residential applications.

Let's consider the case in which it serves as a cleaner against organic pollutants; do you think that these organic compounds adsorbed by biochar may improve its fertilizing properties? Is there a technique to do so?

Bryan: Unfortunately, if you use biochar in water treatment, you cannot control which types of pollutants it will adsorb from water. For this reason, it would be highly risky to use the same biochar as a fertilizer for the soil because it could have adsorbed some chemicals or heavy metals that could negatively affect its fertilizing properties.

What if, due to its initial composition, my final product of biochar contains a high quantity of heavy metals; will this eventuality undermine its capacity to be an efficient tool in water treatment or soil fertilizing?

Experiments with biochar in water. Photo Credit: Robert Tonks

Bryan: Good question, because this is often the case when you treat waste originated by rice cultivation. In those cases, the initial feedstock may contain trace quantities of Arsenic (As2+); however, the temperatures at which the pyrolysis takes place are capable of destroying this.

Thank you, Bryan, on behalf of Amata Green and myself, we really appreciate chatting with you on this topic.

To conclude, biochar is a char-like material that looks to be a valuable resource in fighting the effects of climate change, reducing the CO2 emissions in the atmosphere and is useful in multiple applications like cleaning water. Water filtration with biochar is certainly a growing industry. Research and studies on the topic are growing in numbers in Europe too. However, on the European continent, its applications as soil fertilizer and as water treatment are still poorly-explored. Considering the promising performance and the need to switch towards a more sustainable economy in the next few years, biochar may soon become more widespread on the European market and worldwide. If you would like to learn more about biochar, its applications, sustainability practices or regenerative agriculture, please contact Sandia Martin at AmataGreenConsulting@gmail.com or go to the company’s website at www.AmataGreen.com .

Here you can find Bryan Eagle’s website: https://www.glanris.com

ABOUT THE AUTHOR: Mr. Luca Barani has recently completed a Master’s degree in Resource Economics and Sustainable Development at the University of Bologna in Italy. From his experience working for NGOs on sustainable development projects Mr. Barani has developed a great awareness of climate change and its related effects. Luca will support Amata Green in building a more sustainable and safer world by applying nature-based solutions as mitigation policies against climate change. Mr. Barani can be found on LinkedIn at: https://www.linkedin.com/in/luca-barani-112958b2/

Biochar & Water Filtration: An interview

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