Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 611 - PRIMARY DRINKING WATER STANDARDS › Subpart Z - ENHANCED TREATMENT FOR CRYPTOSPORIDIUM › Section 611.1019 - Requirements for Microbial Toolbox Components: Additional Filtration Toolbox Components

Current through Register Vol. 48, No. 28, July 12, 2024
a) Bag
				and Cartridge Filters. A supplier receives Cryptosporidium treatment credit of
				up to 2.0 -log for individual bag or cartridge filters and up to 2.5 -log for
				bag or cartridge filters operated in series by meeting the criteria set forth
				in subsections (a)(1) through (a)(10). To be eligible for this credit, the
				supplier must report the results of challenge testing that meets the
				requirements of subsections (a)(2) through (a)(9) to the Agency. The filters
				must treat the entire plant flow taken from a Subpart B source.
1) The Cryptosporidium treatment credit
				awarded to bag or cartridge filters must be based on the removal efficiency
				demonstrated during challenge testing that is conducted according to the
				criteria set forth in subsections (a)(2) through (a)(9). A factor of safety
				equal to 1-log for individual bag or cartridge filters and 0.5 -log for bag or
				cartridge filters in series must be applied to challenge testing results to
				determine removal credit. A supplier may use results from challenge testing
				conducted prior to January 5, 2006 if the prior testing was consistent with the
				criteria specified in subsections (a)(2) through (a)(9).
2) Challenge testing must be performed on
				full-scale bag or cartridge filters, and the associated filter housing or
				pressure vessel, that are identical in material and construction to the filters
				and housings the supplier will use for removal of Cryptosporidium. Bag or
				cartridge filters must be challenge tested in the same configuration that the
				supplier will use, either as individual filters or as a series configuration of
				filters.
3) Challenge testing must
				be conducted using Cryptosporidium or a surrogate that is removed no more
				efficiently than Cryptosporidium. The microorganism or surrogate used during
				challenge testing is referred to as the challenge particulate. The
				concentration of the challenge particulate must be determined using a method
				capable of discreetly quantifying the specific microorganism or surrogate used
				in the test; gross measurements such as turbidity may not be used.
4) The maximum feed water concentration that
				can be used during a challenge test must be based on the detection limit of the
				challenge particulate in the filtrate (i.e., filtrate detection limit) and must
				be calculated using the following equation:
Maximum Feed Concentration = 1 x
				  104 x (Filtrate Detection Limit)
5) Challenge testing must be conducted at the
				maximum design flow rate for the filter as specified by the
				manufacturer.
6) Each filter
				evaluated must be tested for a duration sufficient to reach 100 percent of the
				terminal pressure drop, which establishes the maximum pressure drop under which
				the filter may be used to comply with the requirements of this Subpart
				Z.
7) Removal efficiency of a
				filter must be determined from the results of the challenge test and expressed
				in terms of log removal values using the following equation:
LRV = Log10
				  (Cf) - Log10
				  (Cp)
Where:
LRV
=
log removal value demonstrated during challenge
							 testing
Cf
=
the feed concentration measured during the challenge
							 test
Cp
=
the filtrate concentration measured during the
							 challenge test. In applying this equation, the same units must be used for the
							 feed and filtrate concentrations. If the challenge particulate is not detected
							 in the filtrate, then the term Cp must be set equal to
							 the detection limit.
8)
				Each filter tested must be challenged with the challenge particulate during
				three periods over the filtration cycle: within two hours after start-up of a
				new filter; when the pressure drop is between 45 and 55 percent of the terminal
				pressure drop; and at the end of the cycle after the pressure drop has reached
				100 percent of the terminal pressure drop. An LRV must be calculated for each
				of these challenge periods for each filter tested. The LRV for the filter
				(LRVfilter) must be assigned the value of the minimum
				LRV observed during the three challenge periods for that filter.
9) If fewer than 20 filters are tested, the
				overall removal efficiency for the filter product line must be set equal to the
				lowest LRVfilter among the filters tested. If 20 or more
				filters are tested, the overall removal efficiency for the filter product line
				must be set equal to the 10th percentile of the set
				of LRVfilter values for the various filters tested. The
				percentile is defined by (i/(n+1)) where i is the rank of n individual data
				points ordered lowest to highest. If necessary, the
				10th percentile may be calculated using linear
				interpolation.
10) If a previously
				tested filter is modified in a manner that could change the removal efficiency
				of the filter product line, challenge testing to demonstrate the removal
				efficiency of the modified filter must be conducted and submitted in writing to
				the Agency.