Biochar, the product of charring wood under low oxygen conditions, shares many properties with activated charcoal, a common component of at-home water purifiers. Similarly, water purification in built environments can be accomplished by engineered basins with plants and rich porous soil, called bioswales. Several recent studies worldwide have shown that incorporating biochar into bioswale soils can improve their capacity to bind and detoxify water contaminants.

Building on these studies, a bioswale containing biochar on one side and no biochar on the other was engineered into the stormwater drainage area of Veggielution Community Farm in San Jose. This side-by-side setup will allow for a controlled comparison of biochar's impact on bioswale activity. Members of the project team, including Earth Foundries, Sonoma Ecology Center, ReScape, and the North Santa Clara Resource Conservation District, attended an inaugural ceremony at Veggielution on October 5th.

To prepare the foundation for the bioswales, Lyngso Garden Materials of San Carlos donated 70 cubic yards of Biotreatment Mix (60% sand and 40% compost) and 26 cubic yards of composted mulch. On the biochar side, approximately 4 inches of biochar was blended into the mix.

The next step for the project is to wait for the rains to come. Regular water and soil testing will be conducted to monitor the performance of the two sides. The project managers expect the performance of the biochar side to improve over time as the biochar particles become colonized by a microbial community capable of breaking down pollutants.

One way to prime the biochar with such a microbial community is to include it when starting a compost pile. However, as co-composted biochar is not yet available on a commercial scale, the compost and biochar were added separately. Project leaders Raymond Baltar and Roger Smullens (pictured below) have previously worked on a test of biochar co-composting at Napa Recycling that demonstrated biochar's ability to speed the rate of composting, increase the nitrogen retention of the compost, and substantially lower its emissions of volatile organic compounds (VOCs), which are highly regulated by Air Quality Management Districts. Studies elsewhere have found similar benefits, including large reductions in methane emissions. Thus, co-composting with biochar not only makes a better product but also improves the bottom line for composters.

With increasing forest thinning across California, such as the clearing of urban eucalyptus stands for fire control in the East Bay, producing biochar from the cut material presents a way to generate higher-value downstream products and environmental benefits.

Pictured left to right: Raymond Baltar, Climate and Biochar Project Manager, Sonoma Ecology Center; and on the biochar-side of the bioswale, Roger Smullens, CEO, Earth Foundries; and Arun Jani, Assistant Professor of Crop Management, California State University, Monterey Bay.

Our site at Martial Cottle Park for demonstrating small-scale composting and vermicomposting was the focus of this recent feature article and video by UCANR Strategic Communications:
News & Events - Division of Agriculture and Natural Resources 

Welcome to the Organic Materials Management Blog! This is a place for sharing science and policy information on finding valuable uses for organic wastes in California. This site will include news on research findings and the development of innovative practices. Please feel free to comment with your experiences, insights, and any other sources of information you may have.