Resource recovery from low-rank coal and livestock manure for sustainable agroecosystems: a review

The mining and combustion of low-rank coal (LRC), in conjunction with the inadequate management of agricultural waste, notably cattle manure, constitutes a substantial environmental challenge, encompassing greenhouse gas (GHG) emissions and resource inefficiency. However, the co-utilization of these materials offers opportunities for sustainable waste valorization. This review identifies critical knowledge gaps and evaluates recent advances in the combination of LRC and manure for co-composting and bioresource recovery. The findings from the literature review suggest that microbial biodegradation and surfactant-assisted treatments can enhance the transformation of LRC into humic substances, whereas anaerobic digestion and composting can reduce methane emissions from manure. The co-composting of LRC and manure has been identified as a promising pathway to improve soil fertility and carbon sequestration, while mitigating GHG emissions. The present review aims to evaluate microbial, surfactant-assisted, and co-composting strategies for LRC and manure management, with emphasis on agricultural sustainability and climate mitigation. Nevertheless, challenges remain regarding process optimisation, scalability, and economic feasibility. The review concludes with a series of recommendations for future research aimed at integrating these biotechnologies into circular agricultural-energy systems.