N.H. Code Admin. R. Env-Dw 502.12
Treatment complexity shall be determined by a point system, wherein the points are assigned based on factors such as system size, source of water, raw water quality and average variation, chemical treatment processes, disinfection, pH adjustments, corrosion control, clarification, filtration, and other processes as listed in Table 502-2, below:
Table 502-2: Assignment of Points for Treatment Processes
FACTOR | POINTS |
A. System Size | |
1. Design flow average day, or peak month's average day, whichever is larger | 1 per 0.5 million gallons per day (MGD), to a maximum of 20 |
B. Water Supply Source | |
1. Seawater/Saltwater | 0 |
2. Groundwater | 0 |
3. Groundwater under the direct influence of surface water (GWI) | 8 |
4. Surface water | 10 |
C. Average Raw Water Quality Variation | |
1. Little or no variation - no treatment provided except disinfection | 0 |
2. Minor variation - e.g. high quality surface source appropriate for slow sand filtration | 1 |
3. Moderate variation in chemical feed, dosage changes made monthly | 2 |
4. Moderate variation in chemical feed, dosage changes made weekly | 3 |
5. Moderate variation in chemical feed, dosage changes made daily | 4 |
6. Variation significant enough to require pronounced or very frequent changes, or both | 5 |
7. Severe variation - source subject to non-point discharges, agricultural or urban storm runoff, or flooding, or any combination thereof | 7 |
8. Raw water is subject to agricultural or municipal waste point source discharges, or both | 8 |
9. Raw water is subject to industrial waste pollution | 10 |
D. Raw Water Quality | |
1. Taste or odor, or both, for which treatment process adjustments are routinely made | 2 |
2. Color >15 color units (CU) not due to precipitated metals | 3 |
3. Manganese less than maximum contaminant level (MCL) with iron greater than MCL | 2 |
4. Manganese greater than MCL, regardless of iron content | 3 |
5. Algal growths for which treatment process adjustments are routinely made | 3 |
E. Chemical Treatment or Addition Processes | |
1. Fluoridation | 4 |
F. Disinfection/Oxidation | |
1. Hypochlorites not generated on-site | 5 |
2. Hypochlorites generated on-site | 6 |
3. Chlorine gas | 8 |
4. Chloramination | 8 |
5. Chlorine dioxide | 10 |
6. Ozonization | 10 |
7. UV Irradiation | 2 |
8. Iodine, Peroxide, or similar | 5 |
9. Potassium permanganate | |
a. Used without greensand filtration | 4 |
b. Used with greensand filtration | 0 |
G. pH Adjustment for Process Control to Aid Coagulation | 4 |
H. Stability or Corrosion Control | |
1. Same chemical(s) not used for pH adjustment | 4 |
2. Same chemical(s) used for pH adjustment | 0 |
I. Coagulation/Flocculation & Filter Aid | |
1. Primary coagulant addition | 6 |
2. Coagulant aid or flocculant chemical addition to primary coagulant use | 2 |
3. Flocculation | 2 |
4. Filter aid: addition of non-ionic or anionic polymers | 2 |
J. Clarification/Sedimentation | |
1. Sedimentation with plain, tube, or plate | 4 |
2. Contact adsorption | 6 |
3. Other clarification processes such as air flotation or ballasted clarification | 6 |
4. Upflow clarification | 8 |
K. Filtration | |
1. Granular media filtration for surface water or groundwater under the direct influence of surface water <= 3 gpm/sq ft | 10 |
2. Granular media filtration for surface water or groundwater under the direct influence of surface water > 3 gpm/sq ft | 20 |
3. Groundwater filtration | 6 |
4. Membrane filtration | |
a. For compliance with a primary regulation | 10 |
b. For compliance with a secondary regulation | 6 |
5. Diatomaceous earth as pre-coat filtration | 10 |
6. Cartridge or bag | 5 |
7. Pre-filtration staged cartridges or pressure sand without coagulation | 1 per stage to a maximum of 3 |
8. Slow sand | 5 |
L. Other Treatment Processes | |
1. Aeration | 3 |
2. Air stripping, including diffused air, packed tower aeration | 5 |
3. Ion-exchange/softening | 5 |
4. Greensand filtration | 10 |
5. Lime-soda ash softening which includes chemical addition, mixing, flocculation, clarification or filtration, provided that points shall not be added for these processes separately | 20 |
6. Granular activated carbon filter, provided that points shall not be added when included as a bed layer in another filter | 5 |
7. Powdered activated carbon | 2 |
8. Blending sources with significantly different water quality | |
a. To achieve MCL compliance | 4 |
b. For aesthetic reasons | 2 |
9. Reservoir management employing chemical addition | 2 |
10. Electrodialysis | 15 |
11. Other - as determined pursuant to Env-Dw 502.13 | maximum of 20 |
M. Residuals Disposal | |
1. Discharge to sewer or equivalent | 0 |
2. On-site disposal, land application | 1 |
3. Discharge to lagoon/drying bed, with no recovery/recycling | 1 |
4. Backwash recovery or recycling to discharge to basin or lagoon and then to source | 2 |
5. Backwash recovery or recycling to discharge to basin or lagoon and then to plant intake | 3 |
N. Facility Characteristics | |
1. Instrumentation - use of Supervisory Control and Data Acquisition (SCADA) or similar instrumentation to obtain data | |
a. Monitoring or alarm only with no process operation if the plan has no automated shutdown capability | 0 |
b. Limited process operation with remote shutdown capability | 1 |
c. Moderate process operation with alarms and shutdown and plus partial remote operation of plant | 2 |
d. Extensive or total process operation with alarms and shutdown and full remote operation of plant possible | 4 |
N.H. Code Admin. R. Env-Dw 502.12
(See Revision Note at part heading for Env-Dw 502) #9410, eff 3-12-09 (formerly Env-Ws 367.09 )