Nebraska Administrative Code
Topic - HEALTH AND HUMAN SERVICES SYSTEM
Title 179 - PUBLIC WATER SYSTEMS
Chapter 25 - LONG TERM 2 (LT2) ENHANCED SURFACE WATER TREATMENT
Section 179-25-017 - MICROBIAL TOOLBOX OPTIONS FOR MEETING CRYPTOSPORIDIUM TREATMENT REQUIREMENTS

Universal Citation: 179 NE Admin Rules and Regs ch 25 ยง 017

Current through September 17, 2024

017.01 Credits

25-017.01A Systems receive the treatment credits listed in the table in 179 NAC 25-017.02 by meeting the conditions for microbial toolbox options described in 179 NAC 25-018 through 179 NAC 25-022. Systems apply these treatment credits to meet the treatment requirements in 179 NAC 25-013 or 25-014, as applicable.

25-017.01B Unfiltered systems are eligible for treatment credits for the microbial toolbox options described in 179 NAC 25-022 only.

017.02 The following table summarizes options in the microbial toolbox:

Microbial Toolbox Summary Table: Options, Treatment Credits and Criteria

Toolbox Option Cryptosporidium treatment credit with design and implementation criteria

Source Protection and Management Toolbox Options

1. Watershed control program 0.5-log credit for Department-approved program comprising required elements, annual program status report to the Department, and regular watershed survey. Unfiltered systems are not eligible for credit. Specific criteria are in 179 NAC 25-018.01.
2. Alternative source/intake management No prescribed credit. Systems may conduct simultaneous monitoring for treatment bin classification at alternative intake locations or under alternative intake management strategies. Specific criteria are in 179 NAC 25-018.02.
Toolbox Option Cryptosporidium treatment credit with design and implementation criteria

Pre-Filtration Toolbox Options

3. Presedimentation basin with coagulation 0.5-log credit during any month that presedimentation basins achieve a monthly mean reduction of 0.5-log or greater in turbidity or alternative Department-approved performance criteria. To be eligible, basins must be operated continuously with coagulant addition and all plant flow must pass through basins. Specific criteria are in 179 NAC 25-019.01.
4. Two-stage lime softening 0.5-log credit for two-stage softening where chemical addition and hardness precipitation occur in both stages. All plant flow must pass through both stages. Single-stage softening is credited as equivalent to conventional treatment. Specific criteria are in 179 NAC 25-019.02.
5. Bank filtration 0.5-log credit for 25-foot setback; 1.0-log credit for 50-foot setback; aquifer must be unconsolidated sand containing at least 10 percent fines; average turbidity in wells must be less than 1 NTU. Systems using wells followed by filtration when conducting source water monitoring must sample the well to determine bin classification and are not eligible for additional credit. Specific criteria are in 179 NAC 25-019.03.

Treatment Performance Toolbox Options

6. Combined filter performance 0.5-log credit for combined filter effluent turbidity less than or equal to 0.15 NTU in at least 95 percent of measurements each month. Specific criteria are in 179 NAC 25-020.01.
7. Individual filter performance 0.5-log credit (in addition to 0.5-log combined filter performance credit) if individual filter effluent turbidity is less than or equal to 0.15 NTU in at least 95 percent of samples each month in each filter and is never greater than 0.3 NTU in two consecutive measurements in any filter. Specific criteria are in 179 NAC 25-020.02.
8. Demonstration of performance Credit awarded to unit process or treatment train based on a demonstration to the Department with a Department-approved protocol. Specific criteria are in 179 NAC 25-020.03.
Toolbox Option Cryptosporidium treatment credit with design and implementation criteria

Additional Filtration Toolbox Options

9. Bag or cartridge filters (individual filters) Up to 2-log credit based on the removal efficiency demonstrated during challenge testing with a 1.0-log factor of safety. Specific criteria are in 179 NAC 25-021.01.
10. Bag or cartridge filters (in series) Up to 2.5-log credit based on the removal efficiency demonstrated during challenge testing with a 0.5-log factor of safety. Specific criteria are in 179 NAC 25-021.01.
11. Membrane filtration Log credit equivalent to removal efficiency demonstrated in challenge test for device if supported by direct integrity testing. Specific criteria are in 179 NAC 25-021.02.
12. Second stage filtration 0.5-log credit for second separate granular media filtration stage if treatment train includes coagulation prior to first filter. Specific criteria are in 179 NAC 25-021.03.
13. Slow sand filters 2.5-log credit as a secondary filtration step; 3.0-log credit as a primary filtration process. No prior chlorination for either option. Specific criteria are in 179 NAC 25-021.04.

Inactivation Toolbox Options

14. Chlorine dioxide Log credit based on measured CT in relation to CT table.
15. Ozone Log credit based on measured CT in relation to CT table. Specific criteria are in 179 NAC 25-022.02.
16. UV Log credit based on validated UV dose in relation to UV dose table; reactor validation testing required to establish UV dose and associated operating conditions. Specific criteria are in 179 NAC 25-022.04

Disclaimer: These regulations may not be the most recent version. Nebraska may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.