What method typically dewaters solids by mixing with a bulking agent and waiting for biological stabilization?

The correct choice, composting, is a process that allows for the natural degradation of organic solids through biological activity. In composting, solids, such as biosolids from wastewater treatment, are mixed with a bulking agent—materials that improve aeration and structural integrity, like wood chips or straw. This mixture is aerated and turned periodically to facilitate the activity of microorganisms. These microorganisms break down the organic matter, leading to biological stabilization, which ultimately reduces pathogens and odors, resulting in a stable end product that can be used as a soil amendment.

In contrast, incineration is a thermal treatment method that involves burning solids to reduce their volume and destroy organic material but does not involve mixing with a bulking agent or biological stabilization. Centrifuge methods primarily focus on mechanically separating solids from liquids through centrifugal force, which does not involve biological processes. Flotation thickening typically uses air bubbles to help solids clump together and float to the surface for removal, which is a different approach that does not rely on the mixing with bulking agents or biological stabilization.