Ala. Admin. Code r. 335-7-6-.21
Current through Register Vol. 43, No. 1, October 31, 2024
Systems receive treatment credits listed in the following table by meeting the conditions for microbial toolbox options described in rules 335-7-6-.22 through 335-7-6-.26. Systems apply these treatment credits to meet the treatment requirements in rule 335-7-6-.19.
| Microbial Toolbox Summary | |
| Toolbox Option | Cryptosporidium treatment credit with design and implementation criteria |
| Source Protection and Management Toolbox Options (For specific criteria, see rule 335-7-6-.22) | |
| Watershed control program | 0.5-log credit for Departmental approved program comprising required elements, annual program status report to the Department, and regular watershed survey. |
| Alternate 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. |
| Pre-Filtration Toolbox Options(For specific criteria, see rule 335-7-6-.23) | |
| 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. |
| 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. |
| 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. |
| Treatment Performance Toolbox Options (For specific criteria, see rule 335-7-6-.24) | |
| 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. |
| Microbial Toolbox Summary | |
| 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. |
| Demonstration of performance | Credit awarded to unit process or treatment train based on a demonstration to the Department with a Department-approved protocol. |
| Additional Filtration Too box Options (For specific criteria, see rule 335-7-6-.25) | |
| 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. |
| 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. |
| Membrane filtration | Log credit equivalent to removal efficiency demonstrated in challenge test for device if supported by direct integrity testing. |
| Second stage filtration | 0.5-log credit for second separate granular media filtration stage if treatment train includes coagulation prior to first filter. |
| 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. |
| Inactivation Toolbox Options (For specific criteria, see rule 335-7-6-.26) | |
| Chlorine Dioxide | Log credit based on measured CT in relation to CT table. |
| Ozone | Log credit based on measured CT in relation to CT table. |
| 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. |
Ala. Admin. Code r. 335-7-6-.21
Author: Dennis D. Harrison
Statutory Authority:Code of Ala. 1975, §§ 22-23-33, 22-23-49, 22-22A-5, 22-22A-6.