5 Colo. Code Regs. § 1002-11.10

Current through Register Vol. 47, No. 11, June 10, 2024

Section 5 CCR 1002-11.10 - SURFACE WATER TREATMENT RULE: ENHANCED TREATMENT FOR CRYPTOSPORIDIUM

11.10(1)Applicability and Definitions

(a) For all surface water systems with their own surface water sources, the supplier must comply with the requirements specified in this rule.

(i) For wholesale systems and consecutive systems, the wholesaler and, if required, the supplier responsible for the consecutive system must comply with the requirements specified in this rule based on the population of the largest system in the combined distribution system.

(b) The requirements specified in this rule expand on the treatment technique requirements for Cryptosporidium in 11.8.

(c) "BANK FILTRATION" means a water treatment process that uses a well to recover surface water that has naturally infiltrated into groundwater through a river bed or bank(s). Infiltration is typically enhanced by the hydraulic gradient imposed by a nearby pumping water supply or other well(s).

(d) "TWO-STAGE LIME SOFTENING" means a process in which chemical addition and hardness precipitation occur in each of two distinct unit clarification processes in series prior to filtration.

11.10(2)Source Water Monitoring Requirements

(a)General Source Water Monitoring Requirements

(i) The supplier must conduct two rounds of source water monitoring for each treatment plant to determine what level, if any, of additional Cryptosporidium treatment the supplier must provide.

(ii) For new systems, new sources, or reclassified systems that now meet the applicability of this rule, the supplier must conduct an initial round of source water monitoring and begin the monitoring according to a Department-approved schedule.

(A) For systems supplying greater than or equal to (>=) 10,000 people, the supplier must sample all surface water sources for Cryptosporidium, E. coli, and turbidity at least monthly for 24 consecutive months.

(B) For systems supplying less than (<) 10,000 people, the supplier must sample all surface water sources for E. coli at least once every two weeks for 12 consecutive months.

(I) The supplier may conduct Cryptosporidium monitoring as specified in 11.10(2)(a)(ii)(C) instead of conducting E. coli monitoring if the supplier notifies the Department no later than three months before the date the supplier is required to begin E. coli monitoring as specified in Table 11.10-I.

(II) The supplier may use an indicator other than E. coli if the supplier receives written Department-approval that includes the basis for the Department's determination that the alternative indicator will more accurately identify whether the source water requires additional treatment.

(C) For systems supplying less than (<) 10,000 people, the supplier must sample all surface water sources for Cryptosporidium if one of the following conditions are met:

(I) The supplier chooses to conduct Cryptosporidium monitoring instead of E. coli monitoring as specified in 11.10(2)(a)(ii)(B)(I).

(II) Based on monitoring conducted under 11.10(2)(a)(ii)(B), the annual average E. coli concentration is greater than (>) 100 E. coli MPN/100 ml or CFU/100 ml.

(a) The supplier may use an alternative annual average E. coli concentration if the supplier receives written Department-approval that includes the basis for the Department's determination that the alternative annual average E. coli concentration will more accurately identify whether the source water requires additional treatment.

(D) If the supplier is required to conduct source water monitoring for Cryptosporidium under 11.10(2)(a)(ii)(C), the supplier must choose to either monitor at least twice each month for 12 consecutive months or at least monthly for 24 consecutive months.

(E) The supplier may sample more frequently than required if the sampling frequency is evenly spaced throughout the monitoring period.

(iii) The supplier must conduct a second round of source water monitoring that meets the same requirements as the initial round of source water monitoring. The supplier must begin monitoring no later than the month and year specified in Table 11.10-I.

TABLE 11.10-I SOURCE WATER MONITORING START DATES

For systems that:	If the initial round of source water monitoring was required no later than:	The supplier must begin the second round of source water monitoring no later than:
Schedule 1	Supply at least 100,000 people	October 2006	April 2015
Schedule 2	Supply from 50,000 to 99,999 people	April 2007	October 2015
Schedule 3	Supply from 10,000 to 49,999 people	April 2008	October 2016
Schedule 4	Supply less than 10,000 people and only monitor for E. coli	October 2008	October 2017
Schedule 4	Supply less than 10,000 people and monitor for Cryptosporidiu m	April 2010	April 2019
Schedule 5	Are on a Department-approved schedule	As approved by the Department	Six years following the bin classification of the initial round

(iv) For systems or treatment plants that operate for only part of the year, the supplier must conduct source water monitoring as specified in this section, 11.10(2)(a), with the following modifications:

(A) The supplier must conduct source water monitoring only during the months that the treatment plant operates unless the Department specifies another monitoring period based on plant operating practices.

(B) If a treatment plant operates fewer than six months per year and the supplier monitors for Cryptosporidium, the supplier must collect at least six Cryptosporidium source water monitoring samples in each of the two consecutive 12-month periods of the 24-month monitoring period.

(I) The supplier must collect source water samples at a frequency that is evenly spaced throughout the period that the plant operates.

(v) The supplier is not required to conduct source water monitoring if the supplier will provide a total of at least 5.5-log treatment for Cryptosporidium, equivalent to meeting the treatment requirements of a Bin 4 classification as specified in 11.10(4)(a).

(A) If the supplier chooses to provide at least 5.5-log treatment for Cryptosporidium instead of conducting source water monitoring, the supplier must notify the Department in writing no later than three months before the month the supplier is required to begin monitoring in as specified in Table 11.10-I.

(B) The supplier may choose to stop source water monitoring at any time after beginning the monitoring if the supplier notifies the Department in writing that it will provide at least 5.5-log treatment for Cryptosporidium.

(C) The supplier must install and operate technologies to provide at least 5.5-log of treatment for Cryptosporidium no later than the applicable treatment compliance date specified in 11.10(4)(a).

(b)Source Water Monitoring Schedules

(i) The supplier must submit a monitoring schedule that specifies the calendar dates for the collection of each required sample.

(A) For each round of monitoring, the supplier must submit the monitoring schedule no later than three months before the applicable start date specified in Table 11.10-I.

(B) If the Department does not respond to the supplier regarding the monitoring schedule by the beginning date of the schedule, the supplier must sample as specified in the submitted schedule.

(ii) The supplier must collect source water monitoring samples no earlier than two days before and no later than two days after the dates specified in the monitoring schedule (i.e., within a five-day period) unless one of the following conditions applies:

(A) If an extreme condition or situation exists that may pose a danger to the supplier or that cannot be avoided and causes the supplier to be unable to sample in the scheduled five-day period, the supplier must:

(I) Sample as close to the scheduled date as possible unless the Department approves an alternative replacement sampling date.

(II) Submit an explanation for the delayed sample to the Department at the same time the sample is sent to the laboratory.

(B) If the supplier is unable to report a valid analytical sample result for a scheduled sampling date due to: equipment failure; loss of or damage to the sample; failure to comply with the analytical method requirements (including the quality control requirements); or the failure of an approved laboratory to analyze the sample, then the supplier must:

(I) Collect a replacement sample no later than 21 days after receiving notification from the laboratory that a sample result cannot be reported for the scheduled date unless one or more of the following conditions are met:

(a) The supplier demonstrates that collecting a replacement sample within this time frame is not feasible.

(b) The Department approves an alternative replacement sampling date.

(II) Submit an explanation for the delayed sample to the Department at the same time the replacement sample is sent to the laboratory.

(iii) If the supplier fails to collect any source water monitoring sample within the five-day period for any reason other than those specified in 11.10(2)(b)(ii)(A-B), the supplier must revise the monitoring schedule to reschedule all missed samples. The supplier must submit the revised monitoring schedule to the Department for approval before collecting the missed samples.

(c)Source Water Monitoring Sampling Locations

(i) For each round of monitoring, the supplier must submit a description of the sampling location(s) no later than three months before the applicable start date specified in Table 11.10-I.

(A) The description must address the site of the sampling location(s) in relation to the water source(s) and treatment processes, including pretreatment, points of chemical treatment, and filter backwash recycle.

(B) If the Department does not respond to the supplier regarding the sampling location(s) by the beginning date of the monitoring schedule, the supplier must sample at the submitted sampling location(s).

(ii) The supplier must collect source water monitoring samples before each treatment plant that treats a surface water source.

(A) If multiple treatment plants draw water from the same influent, such as the same pipe or intake, the Department may approve one set of source water monitoring sample results from the influent to satisfy the source water monitoring requirements for each treatment plant that uses that influent.

(iii) The supplier must collect source water monitoring samples before all chemical treatment.

(A) If the Department determines that collecting a sample before chemical treatment is not possible for the supplier and that the chemical treatment is unlikely to have a significant adverse effect on the analysis of the sample, the Department may approve the collection of source water monitoring samples after that chemical treatment.

(iv) For systems with treatment plants that use multiple surface water sources or blended surface water and groundwater sources, the supplier must:

(A) Collect source water monitoring samples during normal operating conditions.

(B) If a sampling location where the sources are combined before treatment is available, collect source water monitoring samples from that location.

(C) If a sampling location where the sources are combined before treatment is not available, collect source water monitoring samples from each source's intake on the same day. The supplier must comply with one of the following:

(I) Have a source water monitoring sample analyzed from each source and calculate a weighted average of the sample results based on plant flow at the time the sample is collected.

(II) Composite samples from each source into one sample before analysis.

(a) For composite samples, the volume of water from each source must be proportionate to the use of that source in the total plant flow at the time the sample is collected.

(v) For systems that recycle spent filter backwash water, the supplier must collect source water samples before the location of filter backwash water addition.

(vi) For systems that use bank filtration to comply with 11.8, the supplier must collect source water monitoring samples before the bank filtration.

(vii) For systems that use bank filtration as pretreatment to a filtration treatment plant, the supplier must collect source water monitoring samples after the bank filtration.

(A) The supplier must collect source water monitoring samples during periods of normal operating conditions.

(B) The supplier cannot receive treatment credit for the bank filtration as specified in 11.10(5)(f), to comply with the additional Cryptosporidium treatment technique requirements.

(d)Reporting Requirements for Source Water Monitoring Sample Results

(i) The supplier must submit source water monitoring sample results no later than the 10th of the second month following the month when the sample(s) was collected.

(ii) For each source water monitoring Cryptosporidium sample, the supplier must submit all of the following:

(A) State-assigned facility ID.

(B) Sample collection date.

(C) Sample type (i.e., field or matrix spike).

(D) Filtered sample volume in liters, to the nearest one-fourth liter.

(E) Percentage of filtered sample volume examined.

(F) Number of oocysts counted.

(G) For matrix spike samples, the sample volume spiked and estimated number of oocysts spiked.

(H) For samples where less than 10 liters are filtered or less than 100 percent of the sample volume is examined, the number of filters used and the packed pellet volume.

(I) For samples where less than 100 percent of sample volume is examined, the volume of resuspended concentrate and volume of this resuspension processed through immunomagnetic separation.

(iii) For each source water monitoring E. coli sample, the supplier must submit all of the following:

(A) State-assigned facility ID.

(B) Sample collection date.

(C) Analytical method number.

(D) Method type.

(E) Number of E. coli MPN/100 ml or CFU/100 ml.

(F) For systems supplying greater than or equal to (>=) 10,000 people, turbidity.

(e)Response to Repeated Failures to Monitor for Cryptosporidium

(i) If the supplier fails to monitor in any three months in either round of Cryptosporidium

source water monitoring, the supplier must distribute Tier 2 public notice that:

(A) Meets the requirements specified in 11.33.

(B) Includes the following language and provides the specific information for the text in brackets:

(I) We are required to monitor the source of your drinking water for

Cryptosporidium. Results of the monitoring are to be used to determine whether water treatment at the [treatment plant name] is sufficient to adequately remove Cryptosporidium from your drinking water. We are required to complete this monitoring and make this determination by [required bin determination date]. We "did not monitor or test" or "did not complete all monitoring or testing" on schedule and, therefore, we may not be able to determine by the required date what treatment modifications, if any, must be made to ensure adequate Cryptosporidium removal. Missing this deadline may, in turn, jeopardize our ability to have the required treatment modifications, if any, completed by the deadline required, [date]. For more information, please call [name of water system contact] of [name of water system] at [phone number].

(C) Includes a description of what the supplier is doing to correct the violation and when the supplier expects to return to compliance or resolve the situation.

(f)Grandfathering Previously Collected Source Water Monitoring Sample Results

(i) The supplier is not required to conduct some or all of the initial source water monitoring if the Department approves the grandfathering of source water monitoring samples that were collected before the applicable start date specified in Table 11.10-I.

(ii) For source water monitoring sample results to qualify for grandfathering, the analysis of source water Cryptosporidium samples and/or source water E. coli samples must meet the applicable analytical method and approved laboratory requirements specified in 11.46.

(iii)Cryptosporidium samples collected without corresponding E. coli and turbidity samples may qualify for grandfathering.

(A) If Cryptosporidium samples collected without corresponding E. coli and turbidity samples are grandfathered, the supplier is not required to collect E. coli and turbidity samples when completing the initial source water monitoring requirements for Cryptosporidium.

(iv) For source water monitoring sample results to qualify for grandfathering, the samples must have been collected as follows:

(A) The supplier must have collected Cryptosporidium samples no less frequently than monthly and with regular sample collection intervals.

(I) The supplier may grandfather source water monitoring samples that do not meet the monthly sampling frequency requirement, if the supplier conducts additional Department-specified monitoring to ensure that the source water monitoring sample results are seasonally representative and unbiased.

(II) If sample collection intervals vary for the reasons specified in 11.10(2)(b)(ii)(A-B), the supplier must submit documentation of the conditions that created the variations when reporting the source water monitoring sample results.

(B) The supplier must have collected Cryptosporidium samples no earlier than January 1999.

(C) The sampling location must meet the requirements specified in 11.10(2)(c).

(v) The supplier must submit intent to grandfather source water monitoring sample results no later than three months before the applicable start date specified in Table 11.10-I.

(A) The submission must include all of the following:

(I) The number of previously collected source water monitoring sample results the supplier will submit.

(II) The collection dates of the first and last source water monitoring sample results.

(III) If the supplier will conduct additional source water monitoring to meet the requirements specified in 11.10(2)(a)(ii).

(vi) For each previously collected source water monitoring sample intended for grandfathering, the supplier must submit, for approval, all of the following information no later than two months after the applicable start date specified in Table 11.10-I:

(A) The source water monitoring sample results. The supplier is not required to report matrix spike sample results.

(B) The applicable information as specified in 11.10(2)(d)(ii-iii).

(C) Certification that the submitted source water monitoring sample results include the results of all source water monitoring samples collected between the collection dates of the first reported result and the final reported result that meet the requirements specified in this section, 11.10(2)(f).

(D) Certification that the source water monitoring samples were representative of the treatment plant's source water and that the source water has not changed.

(E) A description of the sampling location which must address the site of the sampling location(s) in relation to the water source(s) and treatment processes, including pretreatment, points of chemical treatment, and filter backwash recycle.

(F) For Cryptosporidium samples, a letter from each laboratory that analyzed the samples certifying that the quality control criteria specified in the approved methods were met for each sample batch associated with the submitted source water monitoring sample results.

(I) Alternatively, the supplier may submit the bench sheets and sample examination report forms from the laboratory for each field, matrix spike, initial precision and recovery, ongoing precision and recovery, and method blank sample that are associated with the submitted source water monitoring sample results.

(vii) If the supplier submits source water monitoring sample results to be grandfathered that were not collected during times of normal source water conditions, such as during a drought, the Department may reject the source water monitoring sample results for grandfathering.

(A) The Department may subsequently approve rejected source water monitoring sample results if the supplier submits any Department-requested additional data about the source water to establish that the source water monitoring sample results are representative of average source water conditions.

(viii) If the supplier submits source water monitoring sample results to be grandfathered that are rejected by the Department and the supplier does not have a sufficient number of sample results to comply with the initial source water monitoring requirements, the supplier must replace the rejected samples by conducting additional source water monitoring as specified in this section, 11.10(2).

(A) The supplier is not required to begin the additional source water monitoring until two months after notification from the Department that samples were rejected and additional source water monitoring is required.

11.10(3)Requirements for Bin Classification

(a)Bin Classification Determination

(i) For systems supplying less than (<) 10,000 people where the supplier only monitored for E. coli and was not required to monitor for Cryptosporidium, the bin classification is Bin 1.

(ii) For systems where the supplier monitored for Cryptosporidium, the supplier must use the source water monitoring sample results from each round of source water monitoring to calculate the average Cryptosporidium concentration as specified in 11.10(3)(a)(iii) and use Table 11.10-II to determine the bin classification.

(iii) For systems where the supplier monitored for Cryptosporidium, after completing each round of source water monitoring, the supplier must calculate that round's average Cryptosporidium concentration using the Cryptosporidium source water monitoring sample results from that round as follows:

(A) If the supplier collected at least 48 samples, the average Cryptosporidium concentration is equal to the average of all sample result concentrations.

(B) If the supplier collected at least 24 samples but fewer than 48 samples, the average Cryptosporidium concentration is equal to the highest RAA of sample result concentrations in the 24 month monitoring period.

(C) If the system supplies less than (<) 10,000 people and the supplier monitored for Cryptosporidium for only 12 months, the average Cryptosporidium concentration is equal to the average of all sample result concentrations.

(D) If the system or treatment plant operates for only part of the year, the average Cryptosporidium concentration is equal to the highest average of all sample result concentrations collected during any year of Cryptosporidium monitoring.

(E) If the supplier collected more than one sample in any month, the supplier must calculate a monthly average of sample result concentrations for each month of monitoring and then use the monthly averages in the applicable calculation specified above in 11.10(3)(a)(iii)(A-D) instead of using individual sample result concentrations.

(iv) Using the average Cryptosporidium concentration calculated above, the supplier must use Table 11.10-II to determine the initial bin classification for the initial round of source water monitoring and the second bin classification for the second round of source water monitoring.

TABLE 11.10-II BIN CLASSIFICATION

For systems with an average Cryptosporidium concentration of:	The bin classification is:
<0.075 oocyst/L	Bin 1
>=0.075 oocyst/L and <1.0 oocyst/L	Bin 2
>=1.0 oocyst/L and <3.0 oocyst/L	Bin 3
>=3.0 oocyst/L	Bin 4

(b)Treatment Technique Requirement for Bin Classification

(i) The supplier must submit the bin classification for each round of source water monitoring for Department approval no later than six months after each round of source water monitoring is required to be completed.

(A) The bin classification submission must include a summary of the individual source water monitoring results and the calculation used to determine the bin classification.

(c)Treatment Technique Violation for Bin Classification

If the supplier fails to comply with the requirements specified in 11.10(3)(b)(i), a bin classification treatment technique violation occurs.

(d)Response to Treatment Technique Violation for Bin Classification

(i) In the event of a bin classification treatment technique violation, the supplier must:

(A) Notify the Department no later than 48 hours after the violation occurs.

(B) Distribute Tier 2 public notice that:

(I) Meets the requirements specified in 11.33.

(II) Includes the following language and provides the specific information for the text in brackets:

(a) We are required to monitor the source of your drinking water for Cryptosporidium in order to determine by [date] whether water treatment at the [treatment plant name] is sufficient to adequately remove Cryptosporidium from your drinking water. We have not made this determination by the required date. Our failure to do this may jeopardize our ability to have the required treatment modifications, if any, completed by the required deadline of [date]. For more information, please call [name of water system contact] of [name of water system] at [phone number].

(III) Includes a description of what the supplier is doing to correct the violation and when the supplier expects to return to compliance.

11.10(4)Requirements for Additional Cryptosporidium Treatment

(a)Treatment Technique Requirements for Additional Cryptosporidium Treatment

(i) Based on the initial bin classification determined under 11.10(3)(a) and the system's current treatment, the supplier must provide the applicable level of additional Cryptosporidium treatment as specified in Table 11.10-III.

(A) If the second bin classification is different than the initial bin classification, the supplier must provide the applicable level of additional Cryptosporidium treatment as specified in Table 11.10-III based on the second bin classification.

TABLE 11.10-III ADDITIONAL CRYPTOSPORIDIUM TREATMENT REQUIREMENTS

Conventional filtration treatment (including softening)	Direct filtration	Slow sand or diatomaceous earth filtration	Alternative filtration technologies (i.e., membrane, bag, cartridge, etc)
Bin 1	No additional treatment	No additional treatment	No additional treatment	No additional treatment
Bin 2	1-log treatment	1.5-log treatment	1-log treatment	As determined by the Department1
Bin 3	2-log treatment	2.5 log treatment	2-log treatment	As determined by the Department2
Bin 4	2.5-log treatment	3-log treatment	2.5-log treatment	As determined by the Department3

1 The total Cryptosporidium removal and inactivation must be at least 4.0-log.

2 The total Cryptosporidium removal and inactivation must be at least 5.0-log.

3 The total Cryptosporidium removal and inactivation must be at least 5.5-log.

(ii) The supplier must use one or more of the treatment and/or management options specified in the Microbial Toolbox in 11.10(5)(b) through 11.10(5)(o) to comply with the additional Cryptosporidium treatment requirements.

(A) For systems classified in Bin 3 or Bin 4, the supplier must achieve at least 1-log of the additional Cryptosporidium treatment by using one or more of the following treatment and/or management options:

(I) Bag filters.

(II) Bank filtration.

(III) Cartridge filters.

(IV) Chlorine dioxide.

(V) Membranes.

(VI) Ozone.

(VII) UV.

(iii) The supplier must begin complying with the additional Cryptosporidium treatment requirements for the initial bin classification no later than the applicable dates specified in Table 11.10-IV.

TABLE 11.10-IV ADDITIONAL CRYPTOSPORIDIUM TREATMENT COMPLIANCE DATES

For systems that were required to conduct source water monitoring as specified in Table 10-1 on:	The supplier must comply with additional Cryptosporidium treatment requirements no later than:1
Schedule 1	April 1, 2012
Schedule 2	October 1, 2012
Schedule 3	October 1, 2013
Schedule 4	October 1, 2014
Schedule 5	As approved by the Department

1 The Department may allow up to an additional two years for complying with the treatment requirement for suppliers making capital improvements.

(iv) The supplier must begin complying with the additional Cryptosporidium treatment requirements for the second bin classification on a Department-approved schedule.

(v) If the Department determines that after the supplier completed either round of source water monitoring significant changes occurred in the system's watershed that could lead to increased Cryptosporidium contamination of the source water, the supplier must take Department-specified actions to address the potential for contamination.

(A) These actions may include additional source water monitoring and/or implementing Microbial Toolbox options specified in 11.10(5)(b) through 11.10(5)(o).

(b)Treatment Technique Violation and Response for Additional Cryptosporidium Treatment

(i) If in any month the supplier fails to maintain the additional Cryptosporidium treatment specified in 11.10(4)(a) by not meeting the applicable criteria of the Microbial Toolbox options specified in 11.10(5)(b) through 11.10(5)(o), a Cryptosporidium treatment technique violation occurs.

(ii) In the event of a Cryptosporidium treatment technique violation, the supplier must:

(A) Notify the Department no later than 48 hours after the violation occurs.

(B) Distribute Tier 2 public notice as specified in 11.33.

11.10(5)Requirements for Microbial Toolbox Options

(a)Microbial Toolbox Options for Meeting Additional Cryptosporidium Treatment Requirements

(i) The supplier must use one or more of the Microbial Toolbox options specified in 11.10(5)(b) through 11.10(5)(o) to comply with the treatment technique requirements for additional Cryptosporidium treatment.

(ii) If the supplier meets the conditions for a Microbial Toolbox option specified in 11.10(5)(b) through 11.10(5)(o), the supplier receives the treatment credits specified in Table 11.10-V for that Microbial Toolbox option.

TABLE 11.10-V MICROBIAL TOOLBOX OPTIONS SUMMARY TABLE: TREATMENT

CREDITS AND CRITERIA

Toolbox option	Cryptosporidium treatment credit	Design and implementation criteria	Criteria specified in:
Watershed control program	0.5-log credit	Department-approved program including required elements, annual program status report to Department, and regular watershed survey.	11.10(5)(b)
Alternative source/intake management	N/A	The supplier may conduct simultaneous monitoring for treatment bin classification at alternative intake locations or under alternative intake management strategies.	11.10(5)(c)
Presedimentation basin with coagulation	0.5-log credit	During any month that presedimentation basins achieve a monthly average reduction of at least a 0.5-log of 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.	11.10(5)(d)
Two-stage lime softening	0.5-log credit	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.	11.10(5)(e)
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.	11.10(5)(f)
Combined filter performance	0.5-log credit	Combined filter effluent turbidity less than or equal ([LESS THAN EQUAL TO]) to 0.15 NTU in at least 95 percent of monitoring results collected each month.	11.10(5)(g)
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 ([LESS THAN EQUAL TO]) 0.15 NTU in at least 95 percent of monitoring results collected each month for each filter and is never greater than (>) 0.3 NTU in two consecutive recordings for any filter.	11.10(5)(h)
Individual Bag or cartridge filters	Up to 2-log credit	Based on the removal efficiency demonstrated during challenge testing with a 1.0-log factor of safety.	11.10(5)(i)
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.	11.10(5)(i)
Membrane filtration	Based on testing results	Log credit equivalent to removal efficiency demonstrated during challenge testing for a device if supported by direct integrity testing.	11.10(5)(j)
Second stage filtration	0.5-log credit	Second granular media filtration stage if treatment train includes coagulation before the first filter.	11.10(5)(k)
Slow sand filters	2.5-log credit as a secondary filtration process; 3.0-log credit as a primary filtration process	Chlorination is not allowed before either option.	11.10(5)(l)
Chlorine dioxide	Based on measured CT in relation to CT table.	11.10(5)(m)
Ozone	Based on measured CT in relation to CT table	11.10(5)(m)
Ultraviolet Light (UV)	Based on validated UV dose in relation to UV dose table	Reactor validation testing required to establish UV dose and associated operating conditions.	11.10(5)(n)
Demonstration of performance	As approved by the Department	Credit awarded to unit process or treatment train based on a demonstration to the Department with a Department-approved protocol.	11.10(5)(o)

(b)Watershed Control Program

(i) The supplier receives 0.5-log Cryptosporidium treatment credit if the supplier implements a watershed control program that meets the requirements specified in this section, 11.10(5)(b).

(ii) If the supplier intends to apply for the watershed control program treatment credit, the supplier must notify the Department of this intent no later than two years before the applicable treatment compliance date specified in 11.10(4)(a).

(iii) The supplier must submit a proposed watershed control plan to the Department for approval no later than one year before the applicable treatment compliance date specified in 11.10(4)(a).

(A) The watershed control plan must include all of the following:

(I) Identification of an area of influence outside of which the likelihood of Cryptosporidium or fecal contamination affecting the treatment plant intake is not significant.

(II) Identification of both potential and actual sources of Cryptosporidium contamination and an assessment of the relative impact of these sources on the system's source water quality.

(III) An analysis of the effectiveness and feasibility of control measures that could reduce Cryptosporidium loading from sources of contamination to the system's source water.

(IV) A statement of goals and specific actions the supplier will take to reduce source water Cryptosporidium levels.

(V) An explanation of how the specific actions are expected to contribute to achieving specific goals.

(VI) Identification of watershed partners and their roles.

(VII) Identification of resource requirements and commitments.

(VIII) A schedule for plan implementation with deadlines for completing specific actions identified in the plan.

(iv) For the supplier to receive watershed control program treatment credit, the Department must approve the watershed control plan.

(A) If the Department does not respond to the supplier regarding approval of a watershed control plan and the supplier meets the requirements specified in this section, 11.10(5)(b), the watershed control program will be considered approved and 0.5 log Cryptosporidium treatment credit will be awarded.

(I) If the Department subsequently finds the watershed control plan to be insufficient the Department may withdraw the approval.

(v) To maintain the 0.5-log Cryptosporidium treatment credit:

(A) The supplier must submit an annual watershed control program status report which must include all of the following:

(I) A description of the supplier's implementation of the approved watershed control plan and an assessment of the adequacy of the plan to meet its goals.

(II) An explanation of how the supplier is addressing any shortcomings in plan implementation, including those identified by the Department or as the result of a watershed sanitary survey.

(III) A description of any significant changes that have occurred in the watershed since the last watershed sanitary survey.

(IV) Any significant changes to the approved watershed control program that the supplier determines during implementation are necessary. The supplier must submit these changes before modifying the approved watershed control program.

(a) If the changes have the potential to reduce the level of source water protection, the supplier must also list in the submission the actions the supplier will take to mitigate this effect.

(B) A watershed sanitary survey must be conducted according to Department guidelines and by a Department-approved party.

(I) The supplier must have a watershed sanitary survey completed:

(a) For community water systems, every three years.

(b) For non-community water systems, every five years.

(II) The supplier must submit the watershed sanitary survey report to the Department.

(III) The watershed sanitary survey must meet all of the following criteria:

(a) Include the area of influence identified in the Department-approved watershed control plan.

(b) Evaluate the implementation of actions to reduce source water Cryptosporidium levels.

(c) Identify any significant new sources of Cryptosporidium.

(C) If the Department determines that significant changes may have occurred in the watershed since the previous watershed sanitary survey, another watershed sanitary survey must be conducted according to a Department-approved schedule.

(D) The supplier must make the watershed control plan, annual watershed control program status report, and watershed sanitary survey reports available to the public upon request.

(I) The documents must be written in plain language and include criteria to evaluate the success of the program in achieving the watershed control plan goals.

(II) If approved by the Department, the supplier may withhold portions of the watershed control plan, annual watershed control program status report, and watershed sanitary survey reports from the public based on source water security considerations.

(vi) If the Department determines that the supplier is not complying with the approved watershed control plan, the Department may withdraw the watershed control program treatment credit.

(c)Alternative Source

(i) If approved by the Department, the supplier may determine the bin classification, as specified in 11.10(3)(a), based on alternative source water monitoring results. If the supplier conducts alternative source water monitoring, the monitoring must meet one of the following criteria:

(A) Be at a different intake location for the current source(s).

(B) Be at an intake location for an alternative source(s).

(C) Use a different procedure for the timing or depth of withdrawal from the current source.

(ii) The supplier must concurrently conduct source water monitoring, as specified in 11.10(2),

and the alternative source water monitoring.

(iii) The supplier must conduct the alternative source water monitoring such that it meets the requirements for source water monitoring to determine bin classification as specified in 11.10(2).

(iv) The supplier must report the alternative source water monitoring results, along with supporting information documenting the operating conditions under which the samples were collected.

(v) If the supplier chooses to determine the bin classification as specified in 11.10(3)(a) using the alternative source water monitoring results instead of using the source water monitoring results from the current source, the supplier must relocate the intake(s) or permanently adopt the withdrawal procedure used in the alternative source water monitoring, no later than the applicable treatment compliance date specified in 11.10(4)(a).

(d)Presedimentation

(i) The supplier receives 0.5-log Cryptosporidium treatment credit for a presedimentation basin in each month that all of the following criteria are met:

(A) The supplier continuously operates the presedimentation basin and treats the entire plant flow coming from the surface water source(s).

(B) The supplier continuously adds a coagulant to the presedimentation basin.

(C) The presedimentation process meets one of the following performance criteria:

(I) Complies with Department-approved performance criteria that demonstrate at least 0.5-log average removal of micron-sized particulate material through the presedimentation process.

(II) Demonstrates at least 0.5-log average reduction of influent turbidity.

(a) The supplier must sample the influent and effluent to the presedimentation process daily for turbidity to determine if the process meets the required average reduction of influent turbidity

(b) The average reduction of influent turbidity must be calculated as follows: log10 (monthly average of daily influent turbidity)-log10 (monthly average of daily effluent turbidity).

(e)Two-stage Lime Softening

(i) The supplier receives 0.5-log Cryptosporidium treatment credit for a two-stage lime softening plant if all of the following criteria are met:

(A) Chemical addition and hardness precipitation occur in two separate and sequential softening stages before filtration.

(B) Both softening stages treat the entire plant flow coming from the surface water source(s).

(f)Bank Filtration

(i) The supplier may receive either of the following Cryptosporidium treatment credit for bank filtration that is used as pretreatment to a filtration plant:

(A) For wells that have a groundwater flow path of at least 25 feet, the supplier receives 0.5-log Cryptosporidium treatment credit.

(B) For wells that have a groundwater flow path of at least 50 feet the supplier receives 1.0-log Cryptosporidium treatment credit.

(ii) The groundwater flow path is determined as follows:

(A) For vertical wells, the groundwater flow path is the measured distance from the well screen to the edge of the surface water body under high flow conditions as determined by the 100 year floodplain elevation boundary or by the floodway, as defined in Federal Emergency Management Agency flood hazard maps.

(B) For horizontal wells, the groundwater flow path is the measured distance from the bed of the river under normal flow conditions to the closest horizontal well lateral screen.

(iii) The supplier receives the Cryptosporidium treatment credit if all of the following criteria are met:

(A) The well is a horizontal or vertical well.

(B) The well is in a granular aquifer which is comprised of sand, clay, silt, rock fragments, pebbles or larger particles, or minor cement.

(I) The supplier must extract a core from the aquifer at the well site and demonstrate that in at least 90 percent of the core length, grains less than 1.0 mm in diameter make up at least 10 percent of the core material.

(C) The supplier monitors each wellhead for turbidity at least every four hours while the bank filtration process is in operation.

(I) If the monthly average turbidity level, based on highest daily turbidity measurements, is greater than (>) 1 NTU, the supplier must conduct an assessment to determine the cause of the exceedance.

(a) The supplier must submit the monthly average turbidity level and the assessment no later than 30 days after the month in which the exceedance occurred.

(II) If the Department determines that microbial removal capability has been compromised, the Department may withdraw the bank filtration treatment credit until the supplier implements Department-approved corrective actions.

(iv) The Department may approve Cryptosporidium treatment credit for bank filtration based on a demonstration of performance study. The treatment credit received may be greater than (>) 1.0-log and may be given to bank filtration that does not meet the criteria specified in 11.10(5)(f)(i-iii).

(A) The study must comply with Department-approved protocol and must involve the collection of data on the removal of Cryptosporidium or a surrogate for Cryptosporidium and related hydrogeologic and water quality parameters during the full range of operating conditions.

(B) The study must include sampling from both the production well(s) and from monitoring well(s) that are screened and located along the shortest flow path between the surface water source and the production well(s).

(v) For systems that were using bank filtration as pretreatment to a filtration treatment plant before beginning source water monitoring and where the supplier collected source water monitoring samples after bank filtration, the supplier cannot receive treatment credit for the bank filtration.

(vi) Springs and infiltration galleries are not eligible for treatment credit under this section, 11.10(5)(f), but are eligible for credit under a demonstration of performance as specified in 11.10(5)(o).

(g)Combined Filter Performance

(i) For systems using conventional filtration treatment or direct filtration treatment, the supplier receives 0.5-log Cryptosporidium treatment credit for combined filter effluent performance for each month the combined filter effluent turbidity monitoring results are less than or equal to ([LESS THAN EQUAL TO]) 0.15 NTU in at least 95 percent of the turbidity monitoring results collected in that month.

(A) Compliance will be based on the combined filter effluent turbidity monitoring results collected under 11.8(2)(c).

(h)Individual Filter Performance

(i) For systems using conventional filtration treatment or direct filtration treatment, the supplier receives 0.5-log Cryptosporidium treatment credit for individual filter effluent performance for each month that all of the following criteria are met, based on the individual filter effluent turbidity monitoring results collected under 11.8(2)(g):

(A) The individual filter effluent turbidity monitoring results are less than or equal to ([LESS THAN EQUAL TO]) 0.15 NTU in at least 95 percent of the turbidity monitoring results collected in that month; and

(B) No individual filter has turbidity monitoring results greater than (>) 0.3 NTU in two consecutive readings collected 15 minutes apart.

(ii) If the supplier fails to meet the requirements specified in 11.10(5)(h)(i) in any month, a Cryptosporidium treatment technique violation, as specified in 11.10(4)(b)(i), does not occur if the Department determines all of the following are met:

(A) That the failure was due to unusual and short-term circumstances that could not reasonably be prevented through optimizing treatment plant design, operation, and maintenance.

(B) That the system has not experienced more than two such failures in any calendar year.

(i)Bag and Cartridge Filters

(i) The supplier receives up to 2.0-log Cryptosporidium treatment credit for an individual bag or cartridge filter and up to 2.5-log Cryptosporidium treatment credit for bag or cartridge filters operated in series that meet the criteria of this section, 11.10(5)(i).

(ii) The bag or cartridge filters must treat the entire plant flow coming from the surface water source(s).

(iii) The level of Cryptosporidium treatment credit received for bag or cartridge filters is based on the removal efficiency demonstrated during challenge testing conducted according to the following criteria:

(A) 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 Cryptosporidium treatment.

(B) Bag or cartridge filters must be challenge tested in the configuration that the supplier will use either as individual filters or as a series of filters.

(C) Challenge testing must be conducted using one or more of the following challenge particulates: Cryptosporidium oocysts or a surrogate that is removed no more efficiently than Cryptosporidium oocysts.

(D) The concentration of the challenge particulate must be determined using a method capable of discretely quantifying the specific challenge particulate used in the test; gross measurements such as turbidity may not be used.

(E) 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)

(F) Challenge testing must be conducted at the maximum design flow rate for the filter as specified by the manufacturer.

(G) Each filter evaluated must be tested until 100 percent of the terminal pressure drop is reached. This establishes the maximum pressure drop under which the filter may be used.

(H) Removal efficiency of the filter must be determined from the results of the challenge test and expressed in terms of log removal values (LRV) 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; and Cp = the filtrate concentration measured during the challenge test.

(I) The same units must be used for the feed and filtrate concentrations.

(II) If the challenge particulate is not detected in the filtrate, then the term Cp must be set equal to the detection limit.

(I) Each filter tested must be challenged with the challenge particulate during the following three challenge periods over the filtration cycle:

(I) Within two hours of start-up of a new filter.

(II) When the pressure drop is between 45 and 55 percent of the terminal pressure drop.

(III) At the end of the cycle after the pressure drop has reached 100 percent of the terminal pressure drop.

(J) The LRV must be calculated for each of the challenge periods for each filter tested. The LRV for the filter (LRVfilter) must be assigned the value of the lowest LRV observed during the three challenge periods for that filter.

(K) If fewer than 20 filters are tested, the overall removal efficiency for the filter product line is equal to the lowest LRVfilter for the filters tested.

(L) If 20 or more filters are tested, the overall removal efficiency for the filter product line is equal to the 10^th percentile of the set of LRVfilter values for the filters tested.

(I) 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 10^th percentile may be calculated using linear interpolation.

(M) To determine removal credit, 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 the challenge testing results.

(N) The supplier must submit the challenge testing results.

(O) If a filter is challenge tested and the filter is later modified in a manner that could change the removal efficiency of the filter product line, the supplier must have a challenge test conducted to demonstrate the removal efficiency of the modified filter and the supplier must submit the test results to the Department.

(j)Membrane Filtration

(i) The supplier receives Cryptosporidium treatment credit for membrane filtration that meets the criteria of this section, 11.10(5)(j). The supplier receives Cryptosporidium treatment credit that is equal to whichever of the following is lower:

(A) The removal efficiency demonstrated during challenge testing conducted as specified in 11.10(5)(j)(ii).

(B) The highest removal efficiency that can be verified through direct integrity testing as specified in 11.10(5)(j)(iii).

(ii) To receive Cryptosporidium treatment credit the membrane used by the system must be challenge tested to demonstrate removal efficiency. The challenge test must be conducted according to the following criteria:

(A) Challenge testing must be performed on either a full-scale membrane module, identical in material and construction to the membrane modules used in the system's treatment plant, or a smaller-scale membrane module, identical in material and similar in construction to the full-scale module.

(I) "MEMBRANE MODULE" means the smallest component of a membrane unit in which a specific membrane surface area is housed in a device with a filtrate outlet structure.

(B) Challenge testing must be conducted using one of the following challenge particulates: Cryptosporidium oocysts or a surrogate that is removed no more efficiently than Cryptosporidium oocysts.

(C) The concentration of the challenge particulate must be determined using a method capable of discretely quantifying the specific challenge particulate used in the test; gross measurements such as turbidity may not be used.

(D) 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 = 3.16 x 10⁶ x (Filtrate Detection Limit)

(E) Challenge testing must be conducted under representative hydraulic conditions at the maximum design flux and maximum design process recovery specified by the manufacturer for the membrane module.

(I) "FLUX" means the throughput of a pressure driven membrane process expressed as flow per unit of membrane area.

(II) "RECOVERY" means the volumetric percent of feed water that is converted to filtrate over the course of an operating cycle uninterrupted by events such as chemical cleaning or a solids removal process (i.e., backwashing).

(F) Removal efficiency (LRVC-Test) of each membrane module tested must be determined from the results of the challenge test and expressed in terms of log removal value using the following equation:

LRVC-Test = LOG10 (Cf) x LOG10 (Cp)

Where:

LRVC-Test = log removal value demonstrated during the challenge test;

Cf = the feed concentration measured during the challenge test; and

Cp = the filtrate concentration measured during the challenge test.

(I) The same units must be used for the feed and filtrate concentrations.

(II) If the challenge particulate is not detected in the filtrate, the term Cp is set equal to the detection limit.

(G) If fewer than 20 modules are tested, then LRVC-Test is equal to the lowest of the calculated LRVs for the modules tested.

(H) If 20 or more modules are tested, then LRVC-Test is equal to the 10^th percentile of the calculated LRVs for the modules tested.

(I) 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 10^th percentile may be calculated using linear interpolation.

(I) The challenge test must establish a quality control release value (QCRV) for a non-destructive performance test that demonstrates the Cryptosporidium removal capability of the membrane module. This performance test must be applied to each production membrane module used by the system that was not directly challenge tested in order to verify Cryptosporidium removal capability.

(I) Production membrane modules that do not meet the established QCRV

are not eligible for the treatment credit demonstrated during the challenge test.

(J) The supplier must submit the results of challenge testing.

(K) If a membrane is challenge tested and the filter is later modified in a manner that could change the removal efficiency of the membrane or the applicability of the non-destructive performance test and associated QCRV, challenge testing must be conducted to demonstrate the removal efficiency and to determine a new QCRV for the modified membrane and the supplier must submit the results to the Department.

(iii) The supplier must conduct direct integrity tests according to the following criteria to demonstrate if the removal efficiency is greater than or equal to the removal credit received for the membrane filtration process:

(A) "DIRECT INTEGRITY TEST" means a physical test applied to a membrane unit in order to identify and isolate integrity breaches (i.e., leaks that could result in contamination of the filtrate).

(B) The direct integrity test must be independently applied to each membrane unit in service.

(I) "MEMBRANE UNIT" means a group of membrane modules that share common valving that allows the unit to be isolated from the rest of the system for the purpose of integrity testing or other maintenance.

(C) The direct integrity test method must have a resolution of three micrometers or less.

(I) "RESOLUTION" means the size of the smallest integrity breach that contributes to a response from the direct integrity test.

(D) The direct integrity test must have a sensitivity sufficient to verify the log treatment credit received for the membrane filtration process.

(I) "SENSITIVITY" means the maximum log removal value that can be reliably verified by a direct integrity test.

(E) Sensitivity must be determined using one of the following approaches based on the type of direct integrity test the supplier uses.

(I) For direct integrity tests that use an applied pressure or vacuum, the direct integrity test sensitivity (LRVdit) must be calculated using the following equation:

LRVdit = LOG10 (Qp / (VCF x Qbreach))

Where:

LRVdit = the sensitivity of the direct integrity test;

Qp = total design filtrate flow from the membrane unit;

Qbreach = flow of water from an integrity breach associated with the smallest integrity test response that can be reliably measured, and

VCF = volumetric concentration factor. The volumetric concentration factor is the ratio of the suspended solids concentration on the high pressure side of the membrane relative to that in the feed water.

(II) For direct integrity tests that use a particulate or molecular marker, the direct integrity test sensitivity (LRVdit) must be calculated using the following equation:

LRVdit = LOG10 (Cf)-LOG10 (Cp)

Where:

LRVdit = the sensitivity of the direct integrity test;

Cf = the typical feed concentration of the marker used in the test; and

Cp = the filtrate concentration of the marker from an integral membrane unit.

(F) The supplier must establish a control limit within the sensitivity limits of the direct integrity test that indicates that an integral membrane unit is capable of meeting the removal credit received.

(G) If the result of a direct integrity test exceeds the control limit established above in 11.10(5)(j)(iii)(F), the supplier must remove the membrane unit from service.

(I) The supplier must conduct a direct integrity test to verify any repairs, and may return the membrane unit to service only if the direct integrity test is within the established control limit.

(H) The supplier must conduct direct integrity testing on each membrane unit at least once on each day the membrane unit is in operation.

(I) The Department may approve less frequent testing based on demonstrated process reliability, the use of multiple barriers effective for Cryptosporidium, or reliable process safeguards.

(iv) The supplier must conduct continuous indirect integrity monitoring on each membrane unit according to the following criteria:

(A) "INDIRECT INTEGRITY MONITORING" means monitoring some aspect of filtrate water quality that is indicative of the removal of particulate matter.

(B) The supplier must conduct continuous indirect integrity monitoring of filtrate turbidity monitoring, unless the Department approves an alternative parameter.

(C) The supplier must collect continuous indirect integrity monitoring samples at least every 15 minutes.

(D) The supplier must conduct continuous indirect integrity monitoring separately for each membrane unit.

(E) If indirect integrity monitoring results for turbidity are greater than (>) 0.15 NTU in two consecutive readings collected 15 minutes apart, the supplier must conduct direct integrity testing immediately, as specified in 11.10(5)(j)(iii), on the membrane unit where the exceedance occurred.

(F) If indirect integrity monitoring for a Department-approved alternative parameter does not meet a Department-approved control limit for a period of 15 minutes or more, the supplier must conduct direct integrity testing immediately, as specified in 11.10(5)(j)(iii), on the membrane unit that did not meet the control limit.

(G) The supplier must submit a monthly report that summarizes all continuous indirect integrity monitoring results that triggered direct integrity testing and the corrective action that was taken in each case.

(H) If the supplier conducts direct integrity testing of membrane units continuously in accordance with the criteria specified in 11.10(5)(j)(iii), the supplier is not required to comply with the continuous indirect integrity monitoring requirements.

(k)Second Stage Filtration

(i) The supplier receives 0.5-log Cryptosporidium treatment credit for a second stage of filtration that consists of sand, dual media, granular activated carbon (GAC), or other fine grain media following granular media filtration.

(ii) To be eligible for this credit:

(A) The first stage of filtration must be preceded by a coagulation step.

(B) Both filtration stages must treat the entire plant flow coming from the surface water source(s).

(C) The Department must approve the treatment credit based on an assessment of the design characteristics of the filtration process.

(iii) A cap, such as GAC, on a single stage of filtration is not eligible for this credit.

(l)Slow Sand Filtration as a Second Stage of Filtration

(i) The supplier receives 2.5-log Cryptosporidium treatment credit for a slow sand filtration process that follows a separate stage of filtration if:

(A) Both filtration stages treat entire plant flow coming from the surface water source(s);

(B) No disinfectant residual is present in the influent water to the slow sand filtration process; and

(C) The Department approves the treatment credit based on an assessment of the design characteristics of the filtration process.

(m)Ozone and Chlorine Dioxide

(i) The supplier receives the Cryptosporidium treatment credit for chlorine dioxide and/or ozone based on daily CT calculations where C and T are monitored during peak hourly flow.

(A) CT is the product of the disinfectant contact time (T, in minutes) and disinfectant concentration (C, in mg/L).

(B) For systems with multiple disinfection segments in sequence, the supplier may calculate CT for each segment and add the Cryptosporidium CT values for each sequential segment of treatment to determine the total CT for the treatment plant.

(ii) For systems using chlorine dioxide treatment, the supplier must calculate daily chlorine dioxide CT values as specified above in 11.10(5)(m)(i) and use Table 11.10-VI to determine the Cryptosporidium treatment log credit achieved by the chlorine dioxide treatment for the applicable water temperature.

TABLE 11.10-VI CT VALUES (MG-MIN/L) FOR CRYPTOSPORIDIUM INACTIVATION BY CHLORINE DIOXIDE¹

Log credit	Water tempe rature , °C	Water temper ature, °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C
[LESS THAN EQUAL TO]0.5	1	2	3	5	7	10	15	20	25	30
0.25	159	153	140	128	107	90	69	45	29	19	12
0.5	319	305	279	256	214	180	138	89	58	38	24
1.0	637	610	558	511	429	360	277	179	116	75	49
1.5	956	915	838	767	643	539	415	268	174	113	73
2.0	1275	1220	1117	1023	858	719	553	357	232	150	98
2.5	1594	1525	1396	1278	1072	899	691	447	289	188	122
3.0	1912	1830	1675	1534	1286	1079	830	536	347	226	147

1 The supplier may use the following equation to determine log credit between the values in the table: Log credit = (0.001506 x (1.09116) Temp) x CT.

(iii) For systems using ozone treatment, the supplier must calculate daily ozone CT values as specified in 11.10(5)(m)(i) and use Table 11.10-VII to determine the Cryptosporidium treatment log credit achieved by the ozone treatment for the applicable water temperature.

TABLE 11.10-VII CT VALUES (MG-MIN/L) FOR CRYPTOSPORIDIUM INACTIVATION BY

OZONE¹

Log credit	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C	Water tempe rature , °C
[LESS THAN EQUAL TO]0.5	1	2	3	5	7	10	15	20	25	30
0.25	6.0	5.8	5.2	4.8	4.0	3.3	2.5	1.6	1.0	0.6	0.39
0.5	12	12	10	9.5	7.9	6.5	4.9	3.1	2.0	1.2	0.78
1.0	24	23	21	19	16	13	9.9	6.2	3.9	2.5	1.6
1.5	36	35	31	29	24	20	15	9.3	5.9	3.7	2.4
2.0	48	46	42	38	32	26	20	12	7.8	4.9	3.1
2.5	60	58	52	48	40	33	25	16	9.8	6.2	3.9
3.0	72	69	63	57	47	39	30	19	12	7.4	4.7

1 The supplier may use the following equation to determine log credit between the values in the table: Log credit = (0.0397 x (1.09757)Temp) x CT.

(n)Ultraviolet Light

(i) The supplier receives the Cryptosporidium treatment credit in Table 11.10-VIII for ultraviolet light (UV) reactors by achieving the corresponding UV dose values in Table 11.10-VIII if:

(A) The supplier applies the UV treatment after filtration.

(B) The supplier uses a low pressure mercury vapor lamp that produces UV light at a wavelength of 254 nm.

(I) To receive treatment credit for other lamp types, the supplier must demonstrate an equivalent germicidal dose through reactor validation testing, as specified in 11.10(5)(n)(i)(C).

(C) The supplier uses UV reactors that have undergone validation testing to determine the validated operating conditions under which the reactor delivers the UV dose required Table 11.10-VIII.

(I) Validation testing must include the following:

(a) Full scale testing of a reactor that represents the UV reactors used by the system; and

(b) Inactivation of a test microorganism whose dose response characteristics have been quantified with a low pressure mercury vapor lamp.

(II) The validated operating conditions must include flow rate, UV intensity as measured by a UV sensor, and UV lamp status.

(III) When determining validated operating conditions, the supplier must account for the following factors:

(a) UV absorbance of the water;

(b) Lamp fouling and aging;

(c) Measurement uncertainty of on-line sensors;

(d) UV dose distributions arising from the velocity profiles through the reactor;

(e) Failure of UV lamps or other critical system components; and

(f) Inlet and outlet piping or channel configurations of the UV reactor.

(D) At least 95 percent of the water supplied to the public during each month is treated by a UV reactor within validated operating conditions for the required UV dose.

(E) The supplier monitors the UV reactor(s) to determine if the treatment meets the criteria in 11.10(5)(n)(i)(C). UV reactor monitoring must include:

(I) UV intensity as measured by a UV sensor;

(a) The supplier must verify the calibration of UV sensors and must recalibrate sensors in accordance with a Department-approved protocol.

(II) Flow rate;

(III) Lamp status; and

(IV) Other parameters the Department designates based on UV reactor operation.

TABLE 11.10-VIII UV DOSE TABLE FOR CRYPTOSPORIDIUM INACTIVATION CREDIT

Log credit	Cryptosporidium UV dose (mJ/cm2)
0.5	1.6
1.0	2.5
1.5	3.9
2.0	5.8
2.5	8.5
3.0	12
3.5	15
4.0	22

(o)Demonstration of Performance

(i) If approved by the Department, the supplier may receive Cryptosporidium treatment credit for treatment processes based on a demonstration of performance study that meets the criteria of this section, 11.10(5)(o). The treatment credit awarded may be greater than or less than the treatment credits specified in the Microbial Toolbox in 11.10(5)(b) through 11.10(5)(m) and may be awarded to treatment processes that do not meet the criteria specified in the Microbial Toolbox.

(A) If the supplier receives treatment credit for a treatment process included in the Microbial Toolbox through this demonstration of performance, the supplier cannot also receive the treatment credit for the Microbial Toolbox option specified in Table 11.10-V and 11.10(5)(b) through 11.10(5)(m).

(B) The supplier must complete the demonstration of performance study according to a Department-approved protocol and must demonstrate the level of Cryptosporidium reduction the treatment process will achieve under the full range of expected system operating conditions.

(C) The supplier must receive Department-approval in writing and the approval may require the supplier to conduct monitoring and demonstrate compliance with treatment performance criteria and submit the results to remain eligible for the treatment credit.

(I) The Department may specify treatment performance criteria to verify that the conditions under which the demonstration of performance credit was approved are maintained during routine operation.

(p)Microbial Toolbox Reporting Requirements

(i) The supplier must submit the information in Table 11.10-IX for any Microbial Toolbox options used to comply with the additional Cryptosporidium treatment requirements.

(A) The Department may approve the supplier to certify operation within required parameters for the additional Cryptosporidium treatment credit rather than reporting monthly operational data for Microbial Toolbox options.

TABLE 11.10-IX MICROBIAL TOOLBOX REPORTING REQUIREMENTS
Toolbox option	The supplier must submit the following information:	No later than:
Watershed control program	Notice of intention to develop a watershed control program.	Two years before the applicable treatment compliance date specified in 11.10(4)(a).
	Watershed control plan.	One year before the applicable treatment compliance date in specified 11.10(4)(a).
	Annual watershed control program status report.	Every 12 months.
	Watershed sanitary survey report.	For community water systems, every three years. For non-community water systems, every five years.
Alternative source/intake management	Verification that the supplier has relocated the intake or adopted the intake withdrawal procedure reflected in monitoring results.	The applicable treatment compliance date specified in 11.10(4)(a).
Presedimentation	Monthly verification of: - Continuous basin operation; - Treatment of 100 percent of the plant flow; - Continuous addition of a coagulant; - At least 0.5-log average reduction of influent turbidity or compliance with alternative Department-approved performance criteria.	The 10th of the month following the month in which the monitoring was conducted.
Two-stage lime Softening	Monthly verification that: - Chemical addition and hardness precipitation occurred in two separate and sequential softening stages before filtration; - Both stages treated 100 percent of the plant flow.	The 10th of the month following the month in which the monitoring was conducted.
Bank Filtration	Initial demonstration of: - Unconsolidated, predominantly sandy aquifer; - Setback distance of at least 25 ft. (0.5-log credit) or 50 ft. (1.0-log credit.	The applicable treatment compliance date specified in 11.10(4)(a).
	If the monthly average turbidity level is greater than (>) 1 NTU, the supplier must report the results and submit an assessment of the cause.	30 days after the month in which the monitoring was conducted.
Combined filter performance	Monthly verification that combined filter effluent turbidity levels are less than or equal ([LESS THAN EQUAL TO]) to 0.15 NTU in at least 95 percent of turbidity monitoring results collected each month.	The 10th of the month following the month in which the monitoring was conducted.
Individual filter performance	Monthly verification that: - Individual filter effluent (IFE) turbidity levels less than or equal to ([LESS THAN EQUAL TO]) 0.15 NTU in at least 95 percent of turbidity monitoring results collected each month at each filter; - No individual filter greater than (>) 0.3 NTU in two consecutive readings.	The 10th of the month following the month in which the monitoring was conducted.
Bag or cartridge filters	Demonstration that the following criteria are met: - Process meets the definition of bag or cartridge filtration; - Removal efficiency established through challenge testing.	The applicable treatment compliance date specified in 11.10(4)(a).
	Monthly verification that 100% of plant flow was filtered.	The 10th of the month following the month in which the monitoring was conducted.
Membrane filtration	Results of verification testing demonstrating: - Removal efficiency established through challenge testing; - Integrity test method and parameters, including resolution, sensitivity, test frequency, control limits, and associated baseline.	The applicable treatment compliance date specified in 11.10(4)(a).
	Monthly report summarizing: - All direct integrity tests above the control limit; - If applicable, any turbidity or alternative Department-approved indirect integrity monitoring results triggering direct integrity testing and the corrective action that was taken.	The 10th of the month following the month in which the monitoring was conducted.
Second stage filtration	Monthly verification that 100 percent of plant flow was filtered through both stages and that first stage was preceded by a coagulation step.	The 10th of the month following the month in which the monitoring was conducted.
Slow sand filters	Monthly verification that both a slow sand filter and a preceding separate stage of filtration treated 100 percent of plant flow from surface water sources.	The 10th of the month following the month in which the monitoring was conducted.
Chlorine dioxide	Summary of CT values for each day as specified in 11.10(5)(m).	The 10th of the month following the month in which the monitoring was conducted.
Ozone	Summary of CT values for each day as specified in 11.10(5)(m).	The 10th of the month following the month in which the monitoring was conducted.
UV	Validation test results demonstrating operating conditions that achieve required UV dose.	The applicable treatment compliance date specified in 11.10(4)(a).
	Monthly report summarizing the percentage of water entering the distribution system that was not treated by UV reactors operating within validated operating conditions for the required dose as specified in 11.10(5)(n).	The 10th of the month following the month in which the monitoring was conducted.
Demonstration of performance	Results from testing following a Department approved protocol.	The applicable treatment compliance date specified in 11.10(4)(a).
	As required by the Department, monthly verification of operation within conditions of Department approval for demonstration of performance credit.	The 10th of the month following the month in which the monitoring was conducted.

5 CCR 1002-11.10

38 CR 07, April 10, 2015, effective 4/30/2015

41 CR 11, June 10, 2018, effective 6/30/2018

41 CR 23, December 10, 2018, effective 12/30/2018

43 CR 07, April 10, 2020, effective 4/30/2020

43 CR 17, September 10, 2020, effective 9/30/2020

45 CR 24, December 25, 2022, effective 1/14/2023