Abstract: A wastewater treatment system and a biological reactor usable in a wastewater treatment system are disclosed. Also disclosed is a media for supporting a growth biology and usable in a biological reactor. Each media includes a tubular cross-section and perturbated outer perimeter, which may be non-nesting. The perturbated outer perimeter creates a protected outer surface area for supporting a growth biology. Also disclosed is a screen sized so as to facilitate retention of the number of media within the biological reactor.

Abstract: A wastewater treatment system including a biological reactor is disclosed. At least one controlled-reaction-volume module is provided to the biological reactor. The at least one controlled-reaction-volume module includes a fixed-film media for supporting a biological growth. At least one mixer, such as, for example, a high momentum mixer, for communicate a fluid to the at least one controlled-reaction-volume module so that wastewater and the biological growth communicate to thereby treat the wastewater.