Section 611.1011  Treatment Technique Requirements:  Filtered System Additional Cryptosporidium Treatment Requirements

a)         A filtered system supplier must provide the level of additional treatment for Cryptosporidium specified in subsections (a)(1) through (a)(4) based on its bin classification, as determined under Section 611.1010, and according to the applicable schedule set forth in Section 611.1013.

1)         If the supplier's bin classification is Bin 1, and the supplier uses conventional filtration treatment (including softening) in full compliance with the applicable provisions of Subparts B, R, and X, no additional treatment is required.

2)         If the supplier's bin classification is Bin 2, and the supplier uses conventional filtration treatment (including softening) in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 1-log treatment.

3)         If the supplier's bin classification is Bin 2, and the supplier uses direct filtration in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 1.5-log treatment.

4)         If the supplier's bin classification is Bin 2, and the supplier uses slow sand or diatomaceous earth filtration in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 1-log treatment.

5)         If the supplier's bin classification is Bin 2, and the supplier uses alternative filtration technologies in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are as determined by the Agency, by a SEP issued under Section 611.110, such that the total Cryptosporidium removal and inactivation is at least 4.0-log.

6)         If the supplier's bin classification is Bin 3, and the supplier uses conventional filtration treatment (including softening) in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 2-log treatment.

7)         If the supplier's bin classification is Bin 3, and the supplier uses direct filtration in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 2.5-log treatment.

8)         If the supplier's bin classification is Bin 3, and the supplier uses slow sand or diatomaceous earth filtration in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 2-log treatment.

9)         If the supplier's bin classification is Bin 3, and the supplier uses alternative filtration technologies in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are as determined by the Agency, by a SEP, such that the total Cryptosporidium removal and inactivation is at least 5.0-log.

10)         If the supplier's bin classification is Bin 4, and the supplier uses conventional filtration treatment (including softening) in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 2.5-log treatment.

11)         If the supplier's bin classification is Bin 4, and the supplier uses direct filtration in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 3-log treatment.

12)         If the supplier's bin classification is Bin 4, and the supplier uses slow sand or diatomaceous earth filtration in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are a 2.5-log treatment.

13)         If the supplier's bin classification is Bin 4, and the supplier uses alternative filtration technologies in full compliance with the applicable provisions of Subparts B, R, and X, then the additional Cryptosporidium treatment requirements are as determined by the Agency, by a SEP, such that the total Cryptosporidium removal and inactivation is at least 5.5-log.

b)         Required Treatment

1)         A filtered system supplier must use one or more of the treatment and management options listed in Section 611.1015, termed the microbial toolbox, to comply with the additional Cryptosporidium treatment required in subsection (a).

2)         A supplier classified in Bin 3 or Bin 4 must achieve at least 1-log of the additional Cryptosporidium treatment required under subsection (a) using either one or a combination of the following: bag filters, bank filtration, cartridge filters, chlorine dioxide, membranes, ozone, or UV, as described in Sections 611.1016 through 611.1020.

c)         A failure by a supplier in any month to achieve treatment credit by meeting criteria in Sections 611.1016 through 611.1020 for microbial toolbox options that is at least equal to the level of treatment required in subsection (a) is a violation of the treatment technique requirement.

d)         If the Agency determines, by a SEP, during a sanitary survey or an equivalent source water assessment that after a supplier completed the monitoring conducted under Section 611.1001(a) or 611.1001(b), significant changes occurred in the supplier's watershed that could lead to increased contamination of the source water by Cryptosporidium, the supplier must take actions specified by the Agency in the SEP to address the contamination.  These actions may include additional source water monitoring or implementing microbial toolbox options listed in Section 611.1015.

BOARD NOTE:  Derived from 40 CFR 141.711.

(Source:  Amended at 44 Ill. Reg. 6996, effective April 17, 2020)