What solids treatment method forms a blanket on the bottom and forces the water out due to compression?

Gravity thickening is a solids treatment method that utilizes the natural force of gravity to separate solids from liquids in wastewater treatment processes. In this method, wastewater is allowed to flow into a thickening tank where the solids settle to the bottom, forming a dense layer known as a blanket. As more solids accumulate over time, this blanket compresses under its own weight, expelling water from the solids through a process known as consolidation.

This separation is crucial because it increases the solids concentration, making further processing or disposal more efficient. The gravity thickening process leverages the difference in density between the solids and the liquid, allowing for effective solid-liquid separation without the need for additional mechanical energy inputs.

In contrast, flotation thickening utilizes air bubbles to lift solid particles to the surface, where they can be skimmed off, and centrifuges use rotational motion to exert centrifugal force for separation. Incineration is a thermal treatment method used for the disposal of solid waste, not for thickening or separating solids from liquids. Thus, the nature of gravity thickening aligns perfectly with the description of forming a blanket and relying on compression to facilitate dewatering.