Indiana Administrative Code › Title 327 - WATER POLLUTION CONTROL DIVISION › Article 8 - PUBLIC WATER SUPPLY › Rule 2.6 - Enhanced Filtration and Disinfection › Section 2.6-15 - Microbial toolbox options for meeting Cryptosporidium treatment requirements; requirements for microbial toolbox components; enhanced treatment for Cryptosporidium

Current through July 10, 2024
Authority: IC 13-13-5; IC 13-14-8; IC 13-14-9; IC 13-18-3; IC
				  13-18-16
Affected: IC
				  13-18-3-11
Sec. 15.
(a) A PWS
				shall:
(1) receive the treatment credits
				listed under Table 15 in subsection (b) by meeting the conditions for microbial
				toolbox options described in sections 16 through 20 of this rule; and
(2) apply the treatment credits received
				under subdivision (1) to meet the treatment requirements in section 12 of this
				rule. (b) The following table summarizes options in the microbial toolbox:
Table 15
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
Watershed Control Plan
0.5-log credit for commissioner-approved program
							 comprising required elements, annual program status, report to commissioner,
							 and regular watershed survey. Specific criteria are under section 16(a) of this
							 rule.
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 under
							 section 16(b) of this rule.
Prefiltration Toolbox Options
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 commissioner-approved performance criteria. To be eligible, basins
							 must be operated continuously with coagulant addition and all plant flow must
							 pass through the basins. Specific criteria are under section 17(a) of this
							 rule.
Two-stage lime softening
0.5-log credit for two-stage lime 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 under section 17(b)
							 of this rule.
Bank filtration
0.5-log credit for 25-foot setback; 1-log credit for
							 50-foot setback; aquifer must be unconsolidated sand containing at least 10%
							 fines; average turbidity in wells must be less than one 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 under section 17(b) of this rule.
Treatment performance toolbox options
Combined filter performance
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 section 18(a) of this rule.
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% of samples each month in each filter and
							 never greater than 0.3 NTU in two consecutive measurements in any filter.
							 Specific criteria are under section 18(b) of this rule.
Demonstration of performance
Credit awarded to unit processes or treatment train
							 based on a demonstration to the commissioner with a commissioner-approved
							 protocol. Specific criteria are under section 18(c) of this rule.
Additional filtration toolbox options
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 under section 19(a) of this rule.
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 under section 19(a) of this rule.
Membrane filtration
Log credit equivalent to removal efficiency
							 demonstrated in challenge test for device if supported by direct integrity
							 testing. Specific criteria are under section 19(b) of this rule.
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 under section 19(c) of this rule.
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 under section 19(d) of this rule.
Inactivation toolbox options
Chlorine dioxide
Log credit based on measured CT in relation to CT
							 table. Specific criteria are under section 20(b) of this rule.
Ozone
Log credit based on measured CT in relation to CT
							 table. Specific criteria are under section 20(b) of this rule.
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 under section 20(d) of
							 this rule.