What material accumulates in a trickling filter or rotating biological contactor?

The accumulation of media in a trickling filter or rotating biological contactor is essential for the treatment process. These systems utilize a surface medium, which can be comprised of various materials such as plastic or stone. This media provides a substrate where biofilms can develop. The microorganisms present in the biofilm are critical for the breakdown of organic materials in the wastewater as it flows over or through the media.

In trickling filters, the wastewater trickles over the media, allowing for contact between the microorganisms and the organic matter in the wastewater, promoting bacterial growth and facilitating the purification process. Similarly, in rotating biological contactors, the media is partially submerged and rotates through the wastewater, enhancing the contact with microorganisms and helping in the degradation of contaminants.

While sludge, gravel, and sand can be involved in the treatment process, they do not serve the same specific function as the media in these systems. Sludge is typically a byproduct of the treatment process and can be removed or further processed. Gravel and sand may be used as base layers or filtration materials, but they do not provide the surface area needed for microbial attachment and growth, which is critical in trickling filters and rotating biological contactors. Thus, the media is pivotal for the success of these biological treatment