Which of the following methods is NOT used for removing contaminants in water treatment?

Habitat restoration is not a method used for directly removing contaminants in water treatment. While habitat restoration can enhance the natural environment and improve ecosystem functions, it does not specifically target the removal of pollutants or pathogens from water sources. This method focuses more on repairing ecosystems to promote biodiversity and sustainability rather than addressing water treatment needs.

On the other hand, biofilm filtration, heat disinfection, and ultrafilter membranes are all established methods for treating contaminated water. Biofilm filtration utilizes natural processes to remove contaminants through the action of microorganisms attached to a substrate, effectively breaking down pollutants. Heat disinfection employs elevated temperatures to eliminate bacteria and viruses, making the water safer for consumption. Ultrafilter membranes use physical barriers to separate particles and microorganisms from water, providing an effective means of purification. These methods are integral to ensuring safe drinking water and maintaining water quality.