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Field Scale Applications of Biochar for Water Remediation: A Review
Citation:
Fang, J., Rosie Wallace, Kevin Wang, C. Su, AND Rick Wilkin. Field Scale Applications of Biochar for Water Remediation: A Review. Presented at American Geophysical Union Fall Meeting, New Orleans, LA, December 13 - 17, 2021.
Impact/Purpose:
This review paper supplements the research we are conducting on using biochar for water remediation. Most research on using biochar has been conducted on a lab scale, and few have been conducted on a large scale. Since the goal is to be able to use biochar for real world applications, this review paper provides us with insight on the current state of research on this topic and identifies knowledge gaps that we can address in future research. The information will be useful for our clients in looking for ways to address water quality issues. The work is of interest to the environmental community, including EPA’s program, regional, and local partners.
Description:
Biochar has received increasing attention in recent years as a cost-competitive adsorbent for contaminants in water. It has been shown to be highly effective for adsorbing a wide variety of heavy metals, organics, nutrients, and microbes. However, most studies have been conducted on a bench scale in the lab. Laboratory conditions do not necessarily reflect the complex and heterogeneous field conditions, as the experiments are typically conducted by investigating biochar’s ability to remove selected contaminants in model solutions (e.g., water with background electrolytes). Under real world conditions, water consists of many components that may interfere with the sorption of a target contaminant. While laboratory studies are useful in investigating the sorption mechanisms for a specific contaminant, they often do not look at how sorption site competition can affect the removal efficiency and reaction rates. Additionally, the concentrations investigated in the laboratory are typically much higher than those found in field water samples. Thus, there is a need for further investigation on the effects of biochar under realistic conditions, especially on the field scale. In this review, a summary of biochar production methods is given, and the physicochemical characteristics that make biochar as an effective adsorbent are described as well. Studies on field scale application of biochar for water remediation are then reviewed. In general, biochar is still an effective adsorbent under field conditions. Finally, knowledge gaps and areas for future research are identified. More field scale studies should be conducted to confirm biochar’s effectiveness as an adsorbent under various conditions. Additionally, most biochars in the literature have been produced on a laboratory scale. However, scaling up biochar tends to produce biochars with less consistent physicochemical characteristics from batch to batch, and biochars used for field applications will be produced on an industrial scale. The effects of scaling up production on biochar quality should therefore also be further investigated.