Wastewater treatment plants will be classified by the Department through the licensing process. Wastewater treatment plants are classified by type (Biological, Physical/Chemical, or Spray Irrigation Treatment System) and grade level following a standard evaluation of the treatment plant. Factors affecting plant classification include design flow, effluent discharge, influent characteristics, preliminary, primary, secondary, tertiary, and physical-chemical treatment, solids handling, disinfection, laboratory, collection system, and system complexity. The Department may upgrade or downgrade an individual treatment plant's classification if the Department finds that its current classification does not properly account for the design, complexity or degree of skill required to operate the plant.
06-096 C.M.R. ch. 531, § 3