DDD Conference

2. Dr. Nadav Ziv

CompoChar: Growing More Food While Fighting Climate Change

Earth Biochar, Israel

Growing plants in a soilless environment allows the grower almost total control over the growing process (water, nutrients, pH, and uptake). Today, most raw materials for soilless substrates are nonrenewable, quarried materials which involve high shipping costs and carbon footprint. The CompoCharTM which is a biochar growing substrate, can be made everywhere from local organic wastes such as wood trimmings and composted sewage sludge (SS), a renewed, nutrient rich raw material. The CompoChar reduces atmospheric CO2 and helps in fighting climate change.

Municipal sewage sludge went through a full composting process. Homogenous ss compost was mixed with shredded wood waste was pyrolyzed at 550°c in a continuous pyrolysis system. The resulting product was characterized for its soilless growing media properties. In addition, pre and post pyrolysis hazardous elements (heavy metals, toxins, pathogens) were measured. Pyrolysis produced a homogenous black material distinct from its original raw material. CompoCharTM has close to ideal water retention curve. The CompoCharTM has a built-in available macro and micro elements found out to be important at times of nutrient stress. CompoCharTM EC is significantly lower compared to SS-compost. Lettuce grown in Compochar weighed 60 gram more than Tuff groups. CompoChar nutrients reservoir lessen blossom-end rot in tomatoes. CompoCharTM blocked fusarium development comparing peat-coco coir growing media. CompoCharTM of H/C ratio measurements were below 0.4 which represent high biological stability appropriate for carbon sequestration. Summary: We find pyrolysis as a promising method to significantly reduce sewage sludge compost hazards and upgrade its value as a soilless growing media.

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