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Wisconsin Administrative Code (Last Updated: January 10, 2017) |
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Agency NR. Department of Natural Resources |
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Chapters 800-. Environmental Protection – Water Supply |
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Chapter 810. Requirements For The Operation And Maintenance Of Public Water Systems |
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SubChapter II. Surface Water Treatment and Groundwater Under the Direct Influence of Surface Water Treatment Operations |
Section 810.36. Cryptosporidium treatment requirements for groundwater under the direct influence of surface water systems that do not filter.
Latest version.
- Section NR 811.42 requires filtration for all surface water sources. The following applies only to GWUDI systems not required to filter.(1) Determination of mean Cryptosporidium level.(a) Following completion of the initial source water monitoring required under s. NR 809.331 (1) , water suppliers for unfiltered systems shall calculate the arithmetic mean of all Cryptosporidium sample concentrations reported under s. NR 809.331 (1) . Water suppliers shall report this value to the department for approval no later than 6 months after the month the system is required to complete initial source water monitoring based on the schedule in s. NR 809.331 (3) .(b) Following completion of the second round of source water monitoring required under s. NR 809.331 (2) , water suppliers for unfiltered systems shall calculate the arithmetic mean of all Cryptosporidium sample concentrations reported under s. NR 809.331 (2) . Water suppliers shall report this value to the department for approval no later than 6 months after the month the system is required to complete the second round of source water monitoring based on the schedule in s. NR 809.331 (3) .(c) If the monthly Cryptosporidium sampling frequency varies, water suppliers shall first calculate a monthly average for each month of monitoring. Systems shall then use these monthly average concentrations, rather than individual sample concentrations, in the calculation of the mean Cryptosporidium level in par. (a) or (b) .(d) The report to the department of the mean Cryptosporidium levels calculated under pars. (a) and (b) shall include a summary of the source water monitoring data used for the calculation.(e) Failure to comply with the conditions of this subsection is a violation of the treatment technique requirement.(2) Cryptosporidium inactivation requirements. Unfiltered systems shall provide the level of inactivation for Cryptosporidium specified in this subsection, based on their mean Cryptosporidium levels as determined under sub. (1) and according to the schedule in s. NR 810.37 .(a) Unfiltered systems with a mean Cryptosporidium level of 0.01 oocysts/L or less shall provide at least 2-log Cryptosporidium inactivation.(b) Unfiltered systems with a mean Cryptosporidium level of greater than 0.01 oocysts/L shall provide at least 3-log Cryptosporidium inactivation.(3) Inactivation treatment technology requirements. Unfiltered systems shall use chlorine dioxide, ozone, or UV as described in s. NR 810.46 to meet the Cryptosporidium inactivation requirements of this section.(a) Unfiltered systems that use chlorine dioxide or ozone and fail to achieve the Cryptosporidium inactivation required in sub. (2) on more than one day in the calendar month are in violation of the treatment technique requirement.(b) Unfiltered systems that use UV light and fail to achieve the Cryptosporidium inactivation required in sub. (2) by meeting the criteria in s. NR 810.46 are in violation of the treatment technique requirement.(4) Use of two disinfectants. Unfiltered systems shall use a minimum of 2 disinfectants to meet the combined Cryptosporidium inactivation requirements of this section along with the Giardia lamblia and virus inactivation requirements of s. NR 810.31 (1) . Each of the 2 disinfectants shall separately achieve the total inactivation required for either Cryptosporidium , Giardia lamblia , or viruses.