Comparison of thermophilic anaerobic and aerobic treatment processes for stabilization of green and food wastes and production of soil amendments Fernández Bayo, Jesús Dionisio Yazdani, Ramin Simmons, Christopher W. VanderGheynst, Jean S. Anaerobic digestion composting Green Waste Food waste This work was funded by the UC Davis Sustainability Research and Training Program and Diamond Developers under collaboration identification number 201500317, the National Institute of Food and Agriculture project CA-D-BAE-2228-RR, and the UC Laboratory Fees Research Program #12-LR-237496. The management of organic wastes is an environmental and social priority. Aerobic digestion (AED) or composting and anaerobic digestion (AD) are two organic waste management practices that produce a value-added final product. Few side-by-side comparisons of both technologies and their digestate products have been performed. The objective of this study was to compare the impact of initial feedstock properties (moisture content and/or C/N ratio) on stabilization rate by AED and AD and soil amendment characteristics of the final products. Green and food wastes were considered as they are two of the main contributors to municipal organic waste. Stabilization rate was assessed by measurement of CH4 and CO2 evolution for AD and AED, respectively. For AD, CH4 yield showed a second-order relationship with the C/N content (P < 0.05); the optimal C/N ratio indicated by the relationship was 25.5. For AED, cumulative CO2 evolution values were significantly affected by the C/N ratio and moisture content of the initial feedstock (P < 0.05). A response surface model showed optimal AED stabilization for a C/N of 25.6 and moisture of 64.9% (wet basis). AD final products presented lower soluble chemical oxygen demand (COD) but lower humification degree and aromaticity than the products from AED. This lower stability may lead to further degradation when amended to soil. The results suggest that composting feedstocks with higher C/N produces an end-product with higher suitability for soil amendment. The instability of end products from AD could be leveraged in pest control techniques that rely on organic matter degradation to produce compounds with pesticidal properties. 2026-02-11T08:47:52Z 2026-02-11T08:47:52Z 2018 journal article Published version: Fernandez-Bayo, J.D., Ramin Yazdani, Christopher W. Simmons and Jean S. VanderGheynst (2018). Comparison of thermophilic anaerobic and aerobic treatment processes for stabilization of green and food wastes and production of soil amendments. Waste Management. Vol 77; 555-564. https://doi.org/10.1016/j.wasman.2018.05.006 https://hdl.handle.net/10481/110855 10.1016/j.wasman.2018.05.006 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License Elsevier