Alabama Administrative Code › Title 335 - ALABAMA DEPARTMENT OF ENVIRONMENTAL MANAGEMENT › WATER DIVISION - WATER SUPPLY PROGRAM › Chapter 335-7-6 - SURFACE WATER SOURCES AND TREATMENT › Section 335-7-6-.21 - Microbial Toolbox Options

Current through Register Vol. 42, No. 9, June 28, 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.
(a) Microbial Toolbox Summary Table: Options,
				Treatment Credits and Criteria:
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.
Author:
Dennis D. Harrison
Statutory Authority:
Code of Ala.
					 1975
, §§
											22-23-33,
					 22-23-49,
					 22-22A-5,
					 22-22A-6.