Utilization of Fly Ash, Bottom Ash, and Local Organic Materials to Support Circular Economy in Coal Mine Reclamation

One of the strategies to improve acidic and nutrient-poor mine land is using organic fertilizers. Considering the large demand for fertilizers in reclamation, it is essential to reuse wastes and residues as resources to produce new products—a concept known as the “circular economy” approach. Fly ash, bottom ash, and local organic waste are abundant materials with the potential for organic fertilizer. Therefore, this study aims to optimize the utilization of fly ash, bottom ash, and local organic material to support the circular economy in the reclamation of coal mine land. The method used is aerobic composting with a passive aerated windrow. Turning and passive pipe aeration are used in this procedure. The results showed that the local organic materials mixed with FABA met the Indonesian National Standard (SNI) quality requirements. Adding 20%-40% FABA is an acceptable dose to meet SNI criteria. This innovation of reutilizing residual organic and non-hazardous waste is useful to extend the life cycle of waste.