Which process is used to separate solids from liquids in wastewater treatment?

The process of separating solids from liquids in wastewater treatment can involve multiple methods, and each of the listed processes is effective in particular contexts.

Precipitation is a chemical process where solid particles form in the water due to a change in conditions, allowing them to settle out of the liquid. This is often used to remove contaminants from wastewater by converting dissolved substances into solid forms, making them easier to separate.

Flotation, on the other hand, uses air bubbles to attach to solid particles, causing them to rise to the surface of the liquid. This process is particularly useful for separating lighter solids, such as fats, oils, and greases, which float to the top and can then be skimmed off.

Filtration is a physical process where water is passed through a filter medium that captures solid particles. This method can vary in complexity, from simple sand filters to more advanced membrane technologies that can remove even very small particles from the wastewater.

Since all these methods effectively separate solids from liquids, the correct answer encompasses all of the above processes. Each technique can be employed depending on the specific characteristics of the wastewater being treated and the solids present.