1. (1) Rating System for Permit Categories.

   1. (a) Unit Operations is defined as any component of a process that could be utilized solely or combined to attain a specific objective. The rating system is based on the number of specified unit operations in a proposed wastewater treatment facility and the total number of points assigned to each unit operation.
   2. (b) Type I Facility -any facility that has less than three unit operations as listed and has a rating of < 20 points.
   3. (c) Type II Facility -any facility that has three or more unit operations as listed or has a rating of > 20 points.

2. (2) The following is the list of unit operations commonly used in wastewater treatment systems.

   Absorption/Adsorption - Carbon 5 - Ion Exchange 5

   Biological Wastewater Treatment - Activated Sludge 6 - Contact beds (anaerobic) 5 - RBC 5 - Sand Filters 4 - Trickling Filters 4

   Chemical Precipitation (reaction vessel) Clarification - Primary 5 - Secondary 5 - Tertiary 5 Chrome Reduction 5 Cooling water (contact and non-contact) 2 Cyanide Destruction 5

   Dentention basins, Swales, Infiltration trenches 2 Disinfection 5

   Equalization 2 Evaporation - Single 2 - Multiple 5

   Filtration/Sludge Dewatering - Cartridge 3 - Centrifuge 8 - Filter Press 8 - Membrane 5 - Vacuum Filter 10 Flocculation/Mixing/Coagulation 5 Flotation 5

   Neutralization/pH Adjust - Single 3 - Multiple 5

   Oil/Water Separation - Gravity fed 2 - Baffled 5

   Pumping (in-plant) 3

   Settling - With manual sludge removal 3 - With mechanical sludge removal 5 Sludge Blending/Thickening 5 Sludge Drying (mechanical dryers) 5 Silver Recovery Unit 5 Stripping (Air/Steam) 5

REGULATORY AUTHORITY

257 CMR 2.00: M.G.L. c. 21, §§ 34A and 34B.