What type of biological treatment involves the use of attached growth media?

The trickling filter is a type of biological treatment that utilizes attached growth media. In this process, wastewater is distributed over a bed of porous media, such as stones or plastic, which provides a surface area for microorganisms to attach and grow. As the wastewater trickles over the media, the attached microorganisms consume organic matter and break down pollutants through biological processes.

This method is effective for treating wastewater because it allows for a relatively simple and low-energy process while facilitating oxygenation. The design fosters aerobic conditions, which are conducive to the growth of aerobic bacteria that are essential for the breakdown of organic substances in the wastewater.

In contrast, other treatment types like the activated sludge process or sequencing batch reactor involve microorganisms that are suspended in the wastewater rather than attached to a growth media. Constructed wetlands, while employing plants and soils for biological treatment, do not primarily rely on the concept of attached growth media in the same way that trickling filters do.