The biofilm on a rotating biological reactor should be what color and shade?

The correct response indicates that the biofilm on a rotating biological reactor should be light brown. This color and shade typically suggest a healthy biofilm composition that is receiving adequate nutrients and oxygen. A light brown biofilm usually signifies an active microbial community, where bacteria are effectively breaking down organic matter in the wastewater.

In a properly functioning reactor, the biofilm must maintain a balance of biomass growth and sloughing to facilitate efficient treatment. The light brown hue often results from the presence of microorganisms, which can include bacteria, protozoa, and other microorganisms involved in the biological treatment process.

The other color options might indicate less optimal conditions: dark green can suggest excessive algae growth or a lack of wastewater treatment efficiency, pale yellow might imply some nutrient deficiency or an unhealthy microbial population, while bright white could indicate the presence of undesirable or non-functional microbial communities, such as filamentous bacteria that can lead to poor treatment performance. Therefore, a light brown biofilm is an indicator of a balanced and functioning biological treatment process in rotating biological reactors.