Code of Massachusetts Regulations
257 CMR - BOARD OF REGISTRATION OF OPERATORS OF WASTEWATER TREATMENT FACILITIES
Title 257 CMR 2.00 - Certification Of Operators Of Wastewater Treatment Facilities
Section 2.13 - Classification of Wastewater Treatment Facilities
Current through Register 1531, September 27, 2024
(1) Each municipal wastewater treatment facility shall be classified by the Board as either 1M, 2M, 3M, 4M or 5, 6, or 7 for large or complex facilities. Each industrial wastewater treatment facility shall be classified as either 1I, 2I, 3I, 4I, or 5, 6, or 7 for large or complex facilities. The increasing numerical class indicates increasing complexity of operation and a higher level of training, knowledge, and experience required for operation.
(2) The class of a facility shall be established by adding together all rating values reflecting the complexity of operation for units which are present in the facility, as set forth below.
Rating Values for Classification of Facilities
| Unit | Rating |
| Aeration; mechanical or diffused air greater than 0.5 MGD | 10 |
| less than 0.5 MGD | 6 |
| Aeration; sludge, re-aeration | 3 |
| Aeration; pure oxygen greater than 0.5 MGD | 10 |
| BOD Removal | 1 and up* |
| Carbon Filter | 2-5 |
| Carbon absorption in an Industrial facility | 5 |
| Carbon reactivation | 10 |
| Centrifuge | 8 |
| Chemical addition | 2 points per chemical |
| Chlorination pre, gas or liquid | 2 |
| Chlorination post, gas or liquid | 2-5 |
| Clarifier, tube settling or inclined plate | 2-5 |
| Clariflocculation | 6 |
| Coagulation and Neutralization | 5 |
| Comminution | 1 |
| Condenser | 2 |
| Cooling Tower | 1-3 |
| Dechlorination | 2 |
| Denitrification | 5 |
| Dissolved Air Flotation | 5 |
| Electrodialysis | 5 |
| Electrolytic Recovery | 5 |
| Equalization | 2 |
| Evaporators | 2-5 |
| Extended Aeration greater than 0.1 MGD, less than 0.5 MGD | 6 |
| Extended Aeration equal to or less than 0.1 MGD | 4 |
| Flash Mixing | 1 |
| Flow measurement | 1 |
| Flocculation | 1 |
| Grit Chamber, Aerated | 2 |
| Grit Chamber manually cleaned | 1 |
| Grit Chamber mechanical grit removal | 2 |
| Heat Exchangers | 2 |
| High rate filtration units less than 0.1 MGD | 1 |
| greater than 0.1 less than 0.5 MGD | 2 |
| greater than 0.5 less than 1.0 MGD | 3 |
| greater than 1.0 MGD | 4 |
| Hypochlorite generation | 5 |
| Hypochlorination pre and/or post | 1 |
| Hydrocyclones (grit removal) | 3 |
| Imhoff tanks | 3 |
| Incineration | 10 |
| Instrumentation | 1-5 |
| Ion Exchange | 2-5 |
| Laboratory | 1-3 |
| Land Irrigation, spraying | 2 |
| Land Irrigation, direct discharge | 2 |
| Membrane Filtration | 3-5 |
| Nitrification | 10 |
| Odor Control | 2-5 |
| Oil Separation | 2 |
| Oxidation Ditch | 5 |
| Oxygen Generation | 10 |
| Ozonation | 5 |
| Polishing Filter | 2 |
| Post-aeration (cascade) | 1 |
| Post-aeration (mechanical) | 2 |
| Pre-aeration | 1 |
| Primary Settling; airlift or manual sludge removal | 3 |
| Primary Settling; mechanical sludge removal | 5 |
| Primary sludge holding and mixing | 2 |
| Pumping (in plant) | 3 |
| Pumping stations under operator's control | 1 |
| Reaction Vessel | 3 |
| Reverse osmosis | 5 |
| Rotating Biological Contactors | 4 |
| Rotating Biological Contactors; multiple stage | 7 |
| Rotary Drum Dryers | 5 |
| Sand filters; multi media, automatic backwash | 3-4 |
| Sand filters; intermittent | 2 |
| Sand filters; polishing | 1 |
| Sand filters; subsurface | 1 |
| Screens (mechanical) | 1 |
| Scum Concentrator | 2 |
| Secondary settling; airlift or manual sludge removal | 3 |
| Secondary settling; mechanical sludge removal | 5 |
| Septage facilities | 2-5 |
| Sludge blending | 2 |
| Sludge composting | 2-5 |
| Sludge drying beds | 2 |
| Sludge digestion; aerobic | 4 |
| Sludge digestion; heated and mixed anaerobic | 10 |
| Sludge digestion; heated and unmixed, anaerobic | 8 |
| Sludge digestion; unheated | 2 |
| Sludge elutriation | 3 |
| Sludge incinerators | 10 |
| Sludge press; belt | 8 |
| Sludge press; plate and frame | 2-8 |
| Sludge storage | 2 |
| Sludge thickeners; gravity | 5 |
| Sludge thickeners; flotation | 5 |
| Stabilization ponds; non-aerated | 1 |
| Stabilization ponds; aerated | 3 |
| Stripping Air 2-5 Steam | 2-5 |
| Trickling filters; high rate | 4 |
| Trickling filters; staged | 4 |
| Trickling filters; standard rate | 2 |
| Ultraviolet disinfection | 2-5 |
| Vacuum filter | 10 |
| Wet Air Oxidation | 10 |
(3) Wastewater treatment facilities shall be classified according to the following cumulative rating value:
|
Class |
Cumulative Rating Value |
|
Class 1 (M or I) |
1-7 |
|
Class 2 (M or I) |
8-20 |
|
Class 3 (M or I) |
21-30 |
|
Class 4 (M or I) |
31-50 |
|
Class 5 (C) |
51-65 |
|
Class 6 (C) |
66-80 |
|
Class 7 (C) |
81 or more |
(4) Class 1 (I) and Class 2 (I) facilities which have fewer than three units or a rating of 20 or fewer points shall be considered Type I facilities for the purposes of 310 CMR 4.00.
(5) Class 1 (I) and Class 2 (I) facilities with greater than three units or a rating of more than 20 points and Class 3 (I), Class 4 (I), Class 5, Class 6, and Class 7 facilities shall be considered Type II facilities for the purposes of 310 CMR 4.00.
(6) The Board may establish a rating value for any unit not shown on the table. The Board may change the classification of a particular wastewater treatment facility when there are site-specific factors affecting the complexity of the treatment process.
