(a) A primary treatment unit may be an aerated lagoon, a partially aerated lagoon, a facultative lagoon, an evaporative lagoon, or an Imhoff tank.
(b) A secondary treatment unit may be a stabilization lagoon, a constructed wetland, an evaporative lagoon, or an overland flow process. A secondary treatment unit may be used for polishing and tertiary treatment.
(c) A treated effluent storage lagoon downstream of the sampling location in the wastewater treatment facility permit is not considered a treatment unit for the purposes of this chapter.
(d) A secondary treatment unit must be preceded by a primary treatment unit.

Source Note: The provisions of this §217.202 adopted to be effective August 28, 2008, 33 TexReg 6843; amended to be effective December 4, 2015, 40 TexReg 8254