Which subtitle is primarily concerned with nonhazardous solid waste disposal?

Subtitle D of the Resource Conservation and Recovery Act (RCRA) is specifically focused on nonhazardous solid waste management. It sets forth regulations for the proper management, recycling, and disposal of nonhazardous solid waste, helping to protect human health and the environment. This subtitle provides the framework for states to develop their own solid waste management programs, ensuring they align with federal guidelines while allowing for local administration based on specific needs and conditions.

Subtitle E relates to the regulation of waste management and disposal specifically concerning energy recovery, while Subtitle B deals with the storage and disposal of hazardous wastes. Subtitle C governs the management of hazardous waste under RCRA, including its generation, transportation, treatment, storage, and disposal. Therefore, Subtitle D is the correct choice because it directly addresses the concerns and guidelines surrounding nonhazardous solid waste.