Volatile Solids as a Reliable Indicator for Compost Quality: A Simplified Approach to Compost Certification for Indian Local Bodies

ABSTRACT Municipal solid waste (MSW) composting is widely promoted as a sustainable approach for managing biodegradable waste. However, existing certification protocols rely on indices such as the C/N ratio, fertilizing index (FI), and clean index (CI), which require advanced instrumentation and are impractical for day‐to‐day application by local bodies, particularly in resource‐limited settings. This study investigates volatile solids (VS) as a simplified alternative parameter for routine compost quality assessment. Small‐scale composting experiments (windrow, vermicomposting, and inoculated microbial composting) and large‐scale municipal compost samples from multiple regions were analyzed. Key properties, including pH, moisture content, nutrients, and heavy metals, were measured for compliance, while the primary focus was on establishing the correlation between VS and total organic carbon (TOC). Regression analysis revealed a strong positive relationship ( R 2 ≈ 0.90), validating VS as a practical proxy for TOC. This finding supports the development of a rapid, cost‐effective, and field‐applicable certification protocol, where VS can serve as the daily testing parameter, complemented by periodic evaluation of FI and CI. The results highlight the potential of VS‐based protocols to streamline compost certification and promote wider adoption of composting practices in decentralized and developing contexts.