Anaerobic Digestion Versus Composting: A Comprehensive Review on Waste Stabilization, Resource Recovery, and Sustainability

Abstract

The rapid growth of organic waste from agricultural, industrial, and municipal activities has raised serious environmental concerns. Anaerobic digestion (AD) and composting (COM) are two widely applied biological technologies developed to stabilize organic waste and recover valuable resources. This review compares their performance, products, environmental impacts, and operational challenges, and discusses the potential benefits of integrating both processes. AD degrades organic matter under anaerobic conditions into biogas and digestate, which can be used as an organic fertilizer due to its high nutrient content. COM is an aerobic self-heating process that transforms organic residues into stable compost suitable for soil improvement. Comparative data show that AD achieves higher degradation rates in shorter residence times, while COM produces a stable product with lower investment and operational complexity. Life cycle assessments indicate that COM has higher energy-related environmental burdens, whereas AD offers better energy recovery but requires higher capital costs and post-treatment of digestate. The integration of AD and COM enables the complementary use of both processes, where AD contributes to methane generation and nutrient retention. At the same time, COM enhances pathogen inactivation and moisture reduction, thereby improving the overall efficiency and sustainability of organic waste management.