Food Waste Composting: Challenges and Possible Approaches

Globally, ~1.3 billion tons of food is wasted or lost, of which 46% arise from downstream processing and emerge as food wastes. Recycling of these wastes is an integral part of the waste management system. Among the various treatment methods, composting is a robust technology having many advantages. However, food waste as substrate to composting presents some unique challenges. Specifically the low pH during the early composting phase due to rapid degradation of organics severely affects the process. The approaches to control the pH such as addition of alkaline substances and microbial inoculation are discussed. Alleviating pH using addition of alkali materials leads to volatilization of ammonia, which reduces the product’s nutrient quality. Thus research on methods to reduce the ammonia emission from the composting mass is gaining momentum, and the pros and cons of different approaches particularly the precipitation of ammonia into struvite are discussed with case studies in this chapter.