Wis. Admin. Code Department of Natural Resources NR 810.41
Current through November 25, 2024
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 department, and regular watershed survey. Unfiltered systems are not eligible for credit. Specific criteria are in s. NR 810.42(1). |
| (2) Alternative source/ intake management | No prescribed credit. Systems may conduct simultaneous monitoring for treatment bin classifica-tion at alternative intake locations or under alternative intake management strategies. Specific criteria are in s. NR 810.42(2). |
| 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 shall be operated continuously with coagulant addition and all plant flow shall pass through basins. Specific criteria are in s. NR 810.43(1). |
| (4) Two-stage lime softening | 0.5-log credit for 2-stage softening where chemical addition and hardness precipitation occur in both stages. All plant flow shall pass through both stages. Single-stage softening is credited as equivalent to conventional treatment. Specific criteria are in s. NR 810.43(2). |
| (5) Bank filtration | 0.5-log credit for 25-foot setback; 1.0-log credit for 50-foot setback; aquifer shall be unconsoli-dated sand containing at least 10% fines; average turbidity in wells shall be less than one NTU. Systems using wells followed by filtration when conducting source water monitoring shall sam-ple the well to determine bin classification and are not eligible for additional credit. Specific criteria are in s. NR 810.43(3). |
| Treatment Performance Toolbox Options | |
| (6) Combined filter per-formance | 0.5-log credit for combined filter effluent turbidity less than or equal to 0.15 NTU in at least 95% of measurements each month. Specific criteria are in s. NR 810.44(1). |
| (7) Individual filter per-formance | 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% of samples each month in each filter and is never greater than 0.3 NTU in 2 consecutive measurements in any filter. Spe-cific criteria are in s. NR 810.44(2). |
| (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 s. NR 810.44(3). |
| Additional Filtration Toolbox Options | |
| (9) Bag or cartridge fil-ters (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 s. NR 810.45(1). |
| (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 s. NR 810.45(1). |
| (11) Membrane filtra-tion | Log credit equivalent to removal efficiency demonstrated in challenge test for device if sup-ported by direct integrity testing. Specific criteria are in s. NR 810.45(2). |
| (12) Second stage filtration | 0.5-log credit for second separate granular media filtration stage if treatment train includes coag-ulation prior to first filter. Specific criteria are in s. NR 810.45(3) |
| Toolbox Option | Cryptosporidium treatment credit with design and implementation criteria |
| Additional Filtration Toolbox Options | |
| (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 s. NR 810.45(4). |
| Inactivation Toolbox Options | |
| (14) Chlorine dioxide | Log credit based on measured CT in relation to CT table. Specific criteria are in s. NR 810.46(2) |
| (15) Ozone | Log credit based on measured CT in relation to CT table. Specific criteria are in s. NR 810.46(2). |
| (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 s. NR 810.46(4). |
Wis. Admin. Code Department of Natural Resources NR 810.41