Food, agriculture, and the environment are intricately connected. In order to sustain a world with a population of 9 billion people by 2050, agriculture and food processing will have to maximize resource utilization. As such, food waste can be utilized either as a soil amendment to enhance sustainable agricultural advantages, or as a sustainable energy source. There is an ongoing effort to reduce the use of hazardous chemicals in soil pest management, and to use instead agricultural waste amendment is one possible solution to the problem. One of the environmentally-friendly processes is anaerobic soil disinfestation (ASD), that when coupled with passive solar heating, is also known as biosolarization. We have used industrial tomato processing waste, which is a common waste stream in California, in a bio-solarized application. By combining laboratory studies with field trials we were able to elucidate the complex biological system of biosolarization. The results showed that our laboratory system that simulates biosolarization, can predict the soil microbial behavior in the field. The laboratory results were later translated into field trials that showed the ability of biosolarization to control pests in a fast and environmental friendly procedure. Using the Next Generation Sequencing (NGS) tool, we were also able to illuminate the complex soil microbial ecology taking place during the biosolarization process. Finally, we have examined for the first time the impact of biosolarization on plant physiology in a way that showed stress reaction trends. This study will be helpful for future implementations of this important sustainable agricultural and waste management technique.
In addition to the biosolarization study we have also tested the ability to use high solids anaerobic digestion by utilizing solids loading rates greater than 10% to reduce water demand. This project explored the technical feasibility of using high solids anaerobic digestion (30% solids) with tomato and grape pomace feedstocks. The results of the project showed the ability to produce high amounts of methane with lower environmental footprints. We also elucidated the microbial community ecology behind the high solid anaerobic digestion by using NGS.
The two projects will help to open new sustainable venues for future industrial food waste valorization.