A viscous jelly-like slime covering a trickling filter or RBC is known as a(n) ___________

The term that describes a viscous jelly-like slime covering a trickling filter or rotating biological contactor (RBC) is "biological growth." This slime is primarily composed of microorganisms, including bacteria, algae, and protozoa, which form a biofilm on the surfaces of the treatment media. This biofilm is crucial for the treatment process, as it provides a surface for these microorganisms to thrive and carry out the degradation of organic materials present in the wastewater.

In a trickling filter or RBC system, the biological growth plays a vital role in removing contaminants through metabolic processes. The thickness and composition of this biofilm can impact the efficiency of the treatment system, influencing factors such as the rate of decomposition of substances and the overall treatment performance.

Other terms listed do not appropriately describe this phenomenon. For instance, "anaerobic film" specifically refers to a biofilm that thrives in an oxygen-free environment, which is not the primary focus of trickling filters or RBCs that typically function in aerobic conditions. The term "population" is too vague and does not accurately convey the nature of the slime, as it does not specify what organism or community is being referred to. "Filter fouling" generally describes the condition where the treatment process is