Code of Colorado Regulations
1000 - Department of Public Health and Environment
1002 - Water Quality Control Commission (1002 Series)
5 CCR 1002-11 - REGULATION NO. 11 - COLORADO PRIMARY DRINKING WATER REGULATIONS
Section 5 CCR 1002-11.8 - SURFACE WATER TREATMENT RULE
Universal Citation: 5 CO Code Regs 1002-11 ยง 8
Current through Register Vol. 47, No. 17, September 10, 2024
11.8(1) General Requirements
(a)
Applicability
and Definitions
(i) For all
surface water systems, the supplier must comply with the requirements specified
in this rule.
(ii) "COMBINED FILTER
EFFLUENT" means a location representative of the filtered water quality which
includes the filter effluent of all filters in use at any given time and is as
close as practical to the point where all individual filter effluents combine
or as approved by the Department.
(iii) "COMPREHENSIVE PERFORMANCE EVALUATION"
or "CPE" means a thorough review and analysis of a treatment plant's
performance capabilities and associated administrative, operational and
maintenance practices. It is conducted to identify factors that may be
adversely impacting a plant's capability to achieve compliance and emphasizes
approaches that can be implemented without significant capital improvements.
The CPE must include at least all of the following components:
(A) Assessment of plant
performance.
(B) Evaluation of
major unit processes.
(C)
Identification and prioritization of performance limiting factors.
(D) Assessment of whether a CTAP would
improve treatment plant performance.
(iv) "COMPREHENSIVE TECHNICAL ASSISTANCE
PROJECT" or "CTAP" means a performance improvement project that uses CPE
results to set priorities for process control improvements and to establish a
long-term training program for staff and administrators.
(v) "FILTER PROFILE" means a graphical
representation of individual filter performance, based on continuous turbidity
measurements or total particle counts versus time for an entire filter run,
from startup to backwash inclusively, that includes an assessment of filter
performance while another filter is being backwashed.
(vi) "INDIVIDUAL FILTER EFFLUENT" means a
location representative of the filtered water quality from an individual
filter's effluent which is at a point before combining with the effluent flow
from other filters.
(vii) "POINT OF
DISINFECTANT APPLICATION" means the point where the disinfectant is applied and
water downstream of that point is not subject to recontamination.
(b)
Treatment
Technique Requirements
(i) The
supplier must provide filtration and disinfection of surface water sources that
meets the treatment technique requirements for all of the following:
Cryptosporidium, Giardia lamblia, viruses, Heterotrophic Plate
Count bacteria, Legionella, and turbidity. These treatment
techniques are as follows:
(A) At a point
between where the source water is not subject to recontamination and the entry
point, the supplier must install and properly operate water treatment processes
that reliably achieve at least the following levels of treatment:
(I) 99 percent (2-log) removal of
Cryptosporidium.
(II) 99.9 percent (3-log) treatment,
including filtration and disinfection, of Giardia
lamblia.
(III) 99.99
percent (4-log) treatment, including filtration and disinfection, of
viruses.
(ii)
The supplier is considered to be in compliance with the requirements specified
in 11.8(1)(b)(i), if the supplier meets all of the following:
(A) The filtration requirements specified in
11.8(2)(b).
(B) The disinfection
requirements specified in 11.8(3)(b).
(iii) Until March 31, 2016, the supplier must
not use uncovered finished water storage facilities.
(A) "UNCOVERED FINISHED WATER STORAGE
FACILITY" means, until March 31, 2016, a tank, reservoir, or other facility
used to store water that will undergo no further treatment except residual
disinfection and that is open to the atmosphere without properly screened
vents, screened overflow pipe, or cover.
(iv) When the Department determines that a
groundwater source is under the direct influence of surface water, and
therefore the system is reclassified as a surface water system, the supplier
must comply with the requirements specified in this section, 11.8(1)(b), no
later than 18 months after receiving written notification from the Department
of the source's reclassification.
11.8(2) Filtration Requirements
(a)
Applicability for Filtration
Requirements
(i) For all surface
water systems, the supplier must comply with the requirements specified in this
section, 11.8(2).
(b)
Treatment Technique Requirements for the Combined Filter
Effluent
(i) The combined filter
effluent treatment technique requirements are as follows:
(A) At the combined filter effluent, the
supplier must:
(I) Maintain treated water
turbidity levels of less than or equal to ([LESS THAN EQUAL TO]) the
95th percentile limit specified in Table 11.8-I in
at least 95 percent of the turbidity monitoring results collected each month.
(a) For systems using slow sand filtration,
the Department may allow an elevated turbidity level if the Department
determines there is no significant interference with disinfection at the
elevated turbidity limit for that system.
(II) Maintain treated water turbidity levels
that are less than or equal to ([LESS THAN EQUAL TO]) the maximum limit
specified in Table 11.8-I at all times.
TABLE 11.8-I TURBIDITY LIMITS
|
For systems using: |
95th percentile limit |
Maximum limit |
|
Conventional Filtration |
0.3 NTU |
1 NTU |
|
Direct Filtration |
0.3 NTU |
1 NTU |
|
Slow Sand Filtration |
1 NTU |
5 NTU |
|
Diatomaceous Earth Filtration |
1 NTU |
5 NTU |
|
Alternative Filtration Technologies -Bag Filtration |
1 NTU |
5 NTU |
|
Alternative Filtration Technologies -Cartridge Filtration |
1 NTU |
5 NTU |
|
Alternative Filtration Technologies -Membranes and all other alternative filtration |
As approved by the Department, but no greater than 1 NTU |
As approved by the Department, but no greater than 5 NTU |
(ii) If approved by the Department, the
supplier may use alternative filtration technologies including membrane
filtration or filtration technologies other than those specified in Table
11.8-I.
(A) In order for the Department to
approve an alternative filtration technology, the supplier must demonstrate,
using pilot plant studies or other means, that the filtration technology, in
combination with the disinfection treatment as specified in 11.8(3)(b),
consistently achieves 99 percent (2-log) removal of
Cryptosporidium, 99.9 percent (3-log) removal and inactivation
of Giardia lamblia, 99.99 percent (4-log) removal and
inactivation of viruses.
(B) If the
Department approves the use of an alternative filtration technology, the
Department shall approve combined filter effluent turbidity limits that are
less than or equal to ([LESS THAN EQUAL TO]):
(I) 1 NTU in 95 percent of measurements
collected each month; and
(II) 5
NTU at any time.
(iii) When the Department determines that a
groundwater source is under the direct influence of surface water, and
therefore the system is reclassified as a surface water system, the supplier
must comply with the requirements specified in this section, 11.8(2)(b), no
later than 18 months after receiving written notification from the Department
of the source's reclassification.
(c)
Monitoring Requirements for
Combined Filter Effluent Treatment Technique Requirements
(i) To determine compliance with the combined
filter effluent treatment technique requirements, the supplier must monitor
turbidity at least every four hours at a location(s) representative of the
combined filter effluent.
(A) The supplier may
monitor turbidity continuously if the supplier validates the continuous
monitoring equipment for accuracy at a Department-approved regular frequency
and using a Department-approved protocol.
(B) The Department may reduce the turbidity
monitoring frequency to daily if the Department determines that less frequent
monitoring is sufficient to indicate effective filtration performance for
systems that meet one or more of the following:
(I) The system uses filtration treatment
other than conventional filtration treatment, direct filtration, or
diatomaceous earth filtration.
(II)
The system supplies less than or equal to ([LESS THAN EQUAL TO]) 500
people.
(ii)
For systems using lime softening, the supplier may acidify turbidity samples
before analysis using a Department-approved protocol.
(iii) When the Department determines that a
groundwater source is under the direct influence of surface water, and
therefore the system is reclassified as a surface water system, the supplier
must comply with the requirements specified in this section, 11.8(2)(c), no
later than when filtration is installed.
(d)
Treatment Technique
Violations for Combined Filter Effluent
(i) The following constitute combined filter
effluent treatment technique violations:
(A)
More than 5 percent of turbidity monitoring results in any month are greater
than (>) the applicable 95th percentile limits specified in Table
11.8-I.
(B) At any time a turbidity
monitoring result is greater than (>) the applicable maximum turbidity limit
specified in Table 11.8-I.
(e)
Response to Combined Filter
Effluent Treatment Technique Violations
(i) In the event of a
95th percentile combined filter effluent turbidity
limit treatment technique violation, as specified in 11.8(2)(d)(i)(A), 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.
(ii)
In the event of a maximum combined filter effluent turbidity limit treatment
technique violation, as specified in 11.8(2)(d)(i)(B), the supplier must
consult with the Department as soon as possible but no later than 24 hours
after the violation occurs.
(A) The
Department shall determine from the consultation whether Tier 1 or Tier 2
public notice is required to protect public health. The supplier must
distribute public notice as specified by the Department.
(B) If the supplier fails to consult with the
Department within 24 hours, the supplier must distribute Tier 1 public notice,
as specified in 11.33, for the violation.
(f)
Reporting Requirements for
Combined Filter Effluent Monitoring
(i) For combined filter effluent turbidity
monitoring results collected under 11.8(2)(c), the supplier must submit the
following information no later than the 10th of the
following month:
(A) Number of combined filter
effluent turbidity monitoring results recorded during the month.
(B) Number and percentage of combined filter
effluent turbidity monitoring results recorded during the month that were
greater than (>) the 95th percentile turbidity limit specified in
11.8(2)(b).
(C) The date and value
of any combined filter effluent turbidity monitoring results collected during
the month, which were greater than (>) the maximum turbidity
limit.
(g)
Monitoring Requirements for Individual Filter Effluent
Turbidity
(i) For systems using
conventional filtration treatment or direct filtration treatment, the supplier
must monitor turbidity continuously at locations representative of each
individual filter effluent.
(A) The supplier
must record the individual filter effluent turbidity monitoring results at
least every 15 minutes.
(B) The
supplier must calibrate the continuous monitoring equipment using the
manufacturer-specified procedure.
(C) If there is a failure of the continuous
monitoring equipment, the supplier must monitor the individual filter effluent
turbidity by collecting a grab sample no later than four hours after the last
recorded monitoring result and continue collecting grab samples every four
hours until the continuous monitoring equipment is returned to service.
(I) For systems supplying greater than or
equal to (>=) 10,000 people, the supplier must resume continuous individual
filter effluent turbidity monitoring no later than five working days after the
equipment failure.
(II) For systems
supplying less than (<) 10,000 people, the supplier must resume continuous
individual filter effluent turbidity monitoring no later than 14 days after the
equipment failure.
(D)
For systems supplying less than (<) 10,000 people that consist of two or
fewer filters, the supplier may conduct continuous combined filter effluent
turbidity monitoring to represent individual filter effluent turbidity
monitoring.
(I) Continuous combined filter
effluent turbidity monitoring must meet the requirements specified in
11.8(2)(g)(i)(A-C).
(E)
For systems using lime softening, the supplier may acidify turbidity samples
before analysis using a Department-approved protocol.
(h)
Reporting Requirements for Individual Filter Effluent Turbidity
Monitoring
For individual filter effluent turbidity monitoring, the supplier must submit documentation that the monitoring was conducted, no later than the 10th of the following month in which the monitoring was conducted.
(i)
Response to Individual Filter
Effluent Turbidity Monitoring Results for Systems Supplying Greater Than or
Equal to (>=) 10,000 People
(i) If the individual filter effluent
turbidity monitoring results at the same filter are greater than
(>) 1.0 NTU in two consecutive recordings collected 15 minutes apart, an exceedance occurs and the supplier must:
(A) Produce a filter profile no later than
seven days after the exceedance if the cause for the exceedance is not
known.
(B) Submit all of the
following no later than the 10th of the month
following the exceedance:
(I) Which filter
exceeded.
(II) Date of the
exceedance.
(III) The turbidity
monitoring results which exceeded 1.0 NTU.
(IV) The cause for the exceedance or if the
cause of the exceedance is not known, documentation that a filter profile was
produced.
(ii) If, in each month, for three consecutive
months, the individual filter effluent turbidity monitoring results at the same
filter are greater than (>) 1.0 NTU in two consecutive recordings collected
15 minutes apart, an exceedance occurs.
(A)
The supplier must conduct a self-assessment of that filter no later than 14
days after the exceedance.
(B) The
self-assessment must include at least all of the following:
(I) Assessment of filter
performance.
(II) Development of a
filter profile.
(III)
Identification and prioritization of factors limiting filter
performance.
(IV) Assessment of the
applicability of corrections.
(V)
Preparation of a written self-assessment report.
(C) In addition to the reporting requirements
specified in 11.8(2)(i)(i)(B), the supplier must submit notification by the
10th of the month following the exceedance that the
self-assessment was conducted.
(iii) If, in each month, for two consecutive
months, the individual filter effluent turbidity monitoring results at the same
filter are greater than (>) 2.0 NTU in two consecutive recordings collected
15 minutes apart, an exceedance occurs.
(A)
The supplier must comply with the reporting requirements specified in
11.8(2)(i)(i)(B).
(B) No later than
30 days after the exceedance occurs, the supplier must arrange for a CPE to be
conducted by the Department or by a Department-approved third party.
(C) No later than 90 days after the
exceedance occurs, the supplier must submit the completed CPE report.
(D) If the CPE indicates the potential for
improved water system performance, the supplier must complete a CTAP.
(I) During the CTAP, the supplier must
identify and systematically address plant-specific factors as outlined in the
CPE and include them in a report submitted no later than 90 days after the
completion of the CPE.
(iv) When a filter is brought online, if
after the first four hours of operation, the individual filter effluent
turbidity monitoring results at that filter are greater than (>) 0.5 NTU in
two consecutive readings collected 15 minutes apart, an exceedance occurs and
the supplier must:
(A) Produce a filter
profile no later than seven days after the exceedance if the cause for the
exceedance is not known.
(B) Submit
all of the following no later than the 10th of the
month following the exceedance:
(I) Which
filter exceeded.
(II) Date of the
exceedance.
(III) The turbidity
monitoring results which exceeded 0.5 NTU.
(IV) The cause for the exceedance or if the
cause of the exceedance is not known, documentation that a filter profile was
produced.
(v)
For systems using lime softening, the supplier may apply to the Department for
higher individual filter effluent turbidity limits than the limits specified in
this section, 11.8(2)(i), if the supplier can demonstrate that higher
individual filter effluent limits are due only to lime carryover and not
degraded filter performance.
(j)
Response to Individual Filter
Effluent Turbidity Monitoring Results for Systems Supplying Less
Than (<) 10,000 People
(i) If the individual filter effluent
turbidity monitoring results at the same filter are greater than
(>) 1.0 NTU in two consecutive recordings collected 15 minutes apart, an exceedance occurs and the supplier must submit all of the following no later than the 10th of the month following the exceedance:
(A) Which
filter exceeded.
(B) Date of the
exceedance.
(C) Turbidity
monitoring results which exceeded 1.0 NTU.
(D) Cause for the exceedance, if
known.
(ii) If, in each
month, for three consecutive months the individual filter effluent turbidity
monitoring results at the same filter are greater than (>) 1.0 NTU in two
consecutive recordings collected 15 minutes apart, an exceedance occurs.
(A) The supplier must conduct a
self-assessment of that filter no later than 14 days after the exceedance
occurs, unless a CPE is required as specified in 11.8(2)(j)(iii).
(I) For systems with two or fewer filters
that monitor combined filter effluent instead of individual filter effluent as
specified in 11.8(2)(g)(i)(D), the supplier must conduct the self-assessment on
both filters.
(B) The
self-assessment must include at least all of the following:
(I) Assessment of filter
performance.
(II) Development of a
filter profile.
(III)
Identification and prioritization of factors limiting filter
performance.
(IV) Assessment of the
applicability of corrections.
(V)
Preparation of a written self-assessment report.
(C) In addition to the reporting requirements
specified in 11.8(2)(j)(i), the supplier must submit all of the following no
later than the 10th of the month following the
exceedance:
(I) The date the self-assessment
was triggered.
(II) The date the
self-assessment was completed.
(iii) If, in each month, for two consecutive
months, the individual filter effluent turbidity monitoring results at the same
filter are greater than (>) 2.0 NTU in two consecutive recordings collected
15 minutes apart, an exceedance occurs.
(A)
No later than 60 days after the exceedance occurs, the supplier must arrange
for a CPE to be conducted by the Department or by a Department-approved third
party.
(B) No later than 120 days
after the exceedance occurs, the supplier must submit the completed CPE
report.
(C) The supplier is not
required to arrange for a CPE and submit a CPE report if:
(I) A CPE has been completed by the
Department or by a Department-approved third party within the last 12 months;
or
(II) The supplier and Department
are participating in an ongoing CTAP at the system.
(D) In addition to the reporting requirements
specified in 11.8(2)(j)(i), if a CPE is required, the supplier must submit all
of the following no later than the 10th of the month
following the exceedance:
(I) That a CPE is
required.
(II) The date the CPE was
triggered.
(E) If the
CPE indicates the potential for improved water system performance, the supplier
must complete a CTAP.
(I) During the CTAP, the
supplier must identify and systematically address plant-specific factors as
outlined in the CPE and include them in a report submitted no later than 90
days after the completion of the CPE.
(iv) For systems using lime softening, the
supplier may apply to the Department for higher individual filter effluent
turbidity limits than the limits specified in this section, 11.8(2)(j), if the
supplier can demonstrate that higher individual filter effluent turbidity
limits are due only to lime carryover and not due to degraded filter
performance.
11.8(3) Disinfection Treatment Technique Requirements
(a)
Applicability for Disinfection Treatment Technique
Requirements
(i) For all surface
water systems, the supplier must comply with the disinfection treatment
technique requirements specified in this section, 11.8(3).
(ii) When the Department determines that a
groundwater source is under the direct influence of surface water, and
therefore the system is reclassified as a surface water system, the supplier
must comply with all of the following:
(A)
Either Department-determined interim disinfection requirements or disinfection
treatment technique requirements specified in 11.8(3)(b), no later than 60 days
after written notification from the Department of the decision to change the
source's classification; and
(B)
All requirements specified in this section, 11.8(3), no later 18 months after
written notification from the Department of the decision to change the source's
classification or no later than when the filtration is installed, whichever is
sooner.
(b)
Treatment Technique Requirements for Disinfection
(i) The disinfection treatment technique
requirements are as follows:
(A) The supplier
must maintain disinfection treatment sufficient to ensure that the total
treatment processes, including filtration and disinfection, achieve 99.9
percent (3-log) treatment of Giardia lamblia cysts and 99.99
percent (4-log) treatment of viruses, as determined by the
Department.
(B) The supplier must
maintain a residual disinfectant concentration at each entry point and
throughout the distribution system.
(I) At
each entry point, the residual disinfectant concentration cannot be less than
(<) 0.2 mg/L for more than four hours.
(II) In the distribution system, the residual
disinfectant concentration cannot be undetectable in more than 5 percent of the
samples collected in each month, for two consecutive months during which the
system supplies water to the public.
(III) In the distribution system, the
residual disinfectant concentration must be greater than or equal to (>=)
0.2 mg/L.
(ii) No later than December 31, 2015, the
supplier may apply to the Department for an extension for complying with the
treatment technique requirements specified in 11.8(3)(b)(i)(B)(III).
(A) In the application, the supplier must
include all of the following information:
(I)
An explanation of why the supplier is unable to comply with the treatment
technique requirements specified in 11.8(3)(b)(i)(B)(III).
(II) A distribution system disinfectant
residual data analysis demonstrating the inability to comply with the treatment
technique requirements specified in 11.8(3)(b)(i)(B)(III).
(III) An engineering report prepared by a
professional engineer registered in the state of Colorado demonstrating that
capital improvements are necessary to comply with the treatment technique
requirements specified in 11.8(3)(b)(i)(B)(III).
(IV) A proposed schedule for completing the
system modifications.
(B) The Department shall consider the
following criteria when determining if an extension will be granted:
(I) The supplier submitted a complete
application that included the information specified above;
(II) The supplier has complied with the
monitoring requirements specified in 11.17 in the last 36 months; and
(III) The supplier has not incurred an MCL
violation specified in 11.17(9) in the last 36 months.
(iii) The Department will only
grant an extension for up to four years.
(iv) If the supplier receives written
Department-approval for an extension, the supplier must:
(A) Continue to comply with the treatment
technique requirements specified in 11.8(3)(b)(i)(B)(II) and is subject to the
violation specified in 11.8(3)(d)(i)(B) until the capital improvements are
completed or the extension expires, whichever comes first; and
(B) Comply with any Department-specified
requirements.
(c)
Monitoring Requirements for
Disinfection Treatment Technique Requirements
(i) To determine compliance with the
disinfection treatment technique requirements, the supplier must monitor the
residual disinfectant concentration.
(A) At
each entry point, the supplier must continuously monitor the residual
disinfectant concentration.
(I) The supplier
must record the lowest monitoring result each day.
(II) If there is a failure of the continuous
monitoring equipment, the supplier must monitor the residual disinfectant
concentration by collecting a grab sample no later than four hours after the
equipment failure and continue collecting grab samples every four hours until
the continuous monitoring equipment is returned to service.
(a) The supplier must resume continuous
residual disinfectant concentration monitoring no later than five working days
after the equipment failure.
(III) For systems supplying less than or
equal to ([LESS THAN EQUAL TO]) 3,300 people, the supplier is not required to
monitor continuously if the supplier collects grab samples at the frequency
specified in Table 11.8-II.
(a) If more than
one sample per day is required, the supplier must collect the samples
throughout the day. The sampling intervals are subject to Department
approval.
(b) If any grab sample
result is less than (<) 0.2 mg/L, the supplier must increase the monitoring
frequency of the residual disinfectant concentration at that entry point to at
least every four hours until the residual disinfectant concentration is greater
than or equal to (>=) 0.2 mg/L.
|
TABLE 11.8-II MINIMUM GRAB SAMPLES |
|
|
Population supplied by the system |
Samples per day |
|
[LESS THAN EQUAL TO] 500 |
1 |
|
501 - 1,000 |
2 |
|
1,001 - 2,500 |
3 |
|
2,501 - 3,300 |
4 |
(B) In the distribution system, the supplier
must monitor the residual disinfectant concentration at the same time and at
the same sampling locations that total coliform samples are collected under
11.16(4).
(I) The supplier must measure the
residual disinfectant concentration as free chlorine unless the supplier uses a
disinfection process that results in a monochloramine residual disinfectant,
then the supplier must measure the residual disinfectant concentration as total
chlorine. If the supplier uses a different type of chemical disinfectant (e.g.,
ozone or chlorine dioxide), the supplier must measure the appropriate residual
disinfectant concentration.
(II)
For systems using both surface water and groundwater sources, the Department
may allow the supplier to collect residual disinfectant concentration samples
at locations other than the total coliform sampling locations if the Department
determines that other locations are more representative of finished water
quality in the distribution system.
(III) A supplier may monitor for
heterotrophic bacteria, measured as Heterotrophic Plate Count (HPC), instead of
disinfectant residual, pursuant to 11.8(3)(g).
(d)
Treatment
Technique Violations for Disinfection
(i) The following constitute disinfection
treatment technique violations:
(A) At any
entry point, the residual disinfectant concentration is less than (<) 0.2
mg/L for more than four hours.
(B)
In the distribution system, the residual disinfectant concentration is not
detectable in more than 5 percent of the samples collected in each month, for
two consecutive months that the system supplies water to the public.
(I) If the Department grants an extension
under 11.8(3)(b)(ii), the supplier is subject to this violation after March 31,
2016 and until capital improvements are completed or the extension expires,
whichever comes first.
(C) In the distribution system:
(I) If the supplier collects greater than or
equal to (>=) 40 residual disinfectant concentration samples per month, the
residual disinfectant concentration is less than (<) 0.2 mg/L in more than 5
percent of the samples collected.
(II) If the supplier collects greater than
(>) one but less than (<) 40 residual disinfectant concentration samples
per monitoring period, the residual disinfectant concentration is less than
(<) 0.2 mg/L in more than one sample collected.
(III) If the supplier collects greater than
(>) one but less than (<) 40 residual disinfectant concentration samples
per monitoring period, the residual disinfectant concentration is less than
(<) 0.2 mg/L in more than 5 percent of the samples collected in each month
for two consecutive months that the system supplies water to the
public.
(IV) If the supplier
collects only one residual disinfectant concentration sample per monitoring
period, the residual disinfectant concentration is less than (<) 0.2
mg/L.
(D) Any time the
supplier fails to comply with the treatment technique requirements specified in
11.8(3)(b)(i)(A).
(e)
Response to Disinfection
Treatment Technique Violations
(i) In the event of an entry point
disinfection treatment technique violation as specified in 11.8(3)(d)(i)(A),
the supplier must:
(A) Notify the Department
no later than the end of the next business day.
(B) Distribute Tier 2 public notice as
specified in 11.33.
(ii)
In the event of a disinfection treatment technique violation as specified in
11.8(3)(d)(i)(B-
D), 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.
(f)
Reporting Requirements for
Disinfection Monitoring
(i) If at
any time the entry point residual disinfectant concentration is less than
(<) 0.2 mg/L, the supplier must notify the Department as soon as possible
but no later than the end of the next business day.
(A) The supplier must also report, no later
than the end of the next business day, whether the entry point residual
disinfectant concentration was restored to at least 0.2 mg/L within four
hours.
(ii) For residual
disinfectant concentration samples collected under 11.8(3)(c), the supplier
must submit all of the following information no later than the
10th of the following month:
(A) For each entry point, the lowest daily
residual disinfectant concentration result in mg/L.
(B) The date and duration of each period when
the entry point residual disinfectant concentration fell below 0.2 mg/L and
when the Department was notified of the occurrence.
(C) For distribution system residual
disinfectant concentration samples:
(I) The
number of sample results that were less than (<) 0.2 mg/L.
(II) The percentage of sample results that
were less than (<) 0.2 mg/L for each of the last two months.
(g)
Monitoring Requirements for Alternative Disinfection- Heterotrophic
Bacteria
(i) In the distribution
system, the supplier may monitor for heterotrophic bacteria, measured as
Heterotrophic Plate Count (HPC), instead of residual disinfectant
concentration, pursuant to 11.8(3)(c).
(A) If
the supplier is monitoring for heterotrophic bacteria instead of residual
disinfectant concentration, the samples must be analyzed under 11.46(2)(f).
Heterotrophic bacteria concentrations less than or equal to ([LESS THAN EQUAL
TO]) 500 CFU/ml are considered to have a detectable residual disinfectant
concentration for purposes of determining compliance with the treatment
technique requirement specified in 11.8(3)(b)(i)(B)(II) and must be included
with the reporting requirements specified in 11.8(3)(f)(ii)(C).
(B) If the supplier is monitoring for
heterotrophic bacteria, the supplier is not required to comply with the
requirements for the distribution system residual disinfectant concentration
specified in this section, 11.8(3) if the Department determines that the
supplier meets all of the following criteria:
(I) Providing adequate disinfection in the
distribution system.
(II) Not
capable of having a sample transported and analyzed for HPC by a certified
laboratory within the required time and temperature conditions specified by
approved analytical methods.
11.8(4) Disinfection Profiling
The purpose of disinfection profiling and benchmarking is to allow the supplier and the Department to assess whether a change in disinfection practices creates a microbial risk. The supplier must develop a disinfection profile, calculate a benchmark (lowest monthly inactivation) based on the profile, and consult with the Department before making a significant change to disinfection.
(a)
Applicability and Definitions for Disinfection
Profiling
(i) For new surface
water systems or reclassified systems that now meet the applicability of this
rule, applicability for this section, 11.8(4), is determined by evaluating TTHM
and HAA5 sample results. Applicability must be determined no later than 12
months after the system is classified as a surface water system.
(A) The supplier must collect TTHM and HAA5
samples that meet the routine sampling requirements specified in 11.25(1)(c)
and submit the results to the Department. Alternatively, the supplier may:
(I) Request that the Department approve the
use of a more appropriate data set for determination of applicability;
or
(II) Choose not to collect the
TTHM and HAA5 data, if the supplier notifies the Department of the decision.
The supplier must then develop a disinfection profile to determine log
inactivation of Giardia lamblia under
11.8(4)(a)(i)(B).
(B)
The supplier must comply with the treatment technique requirement to develop a
disinfection profile to determine log inactivation of Giardia
lamblia if the system meets either of the following criteria:
(I) A system supplying greater than or equal
to (>=) 10,000 people and has a TTHM annual average of quarterly samples
greater than or equal to (>=) 0.064 mg/L or has an HAA5 annual average of
quarterly samples greater than or equal to (>=) 0.048 mg/L.
(II) A community or non-transient,
non-community water systems supplying less than (<) 10,000 people and has a
TTHM sample result greater than or equal to (>=) 0.064 mg/L or has an HAA5
sample result greater than or equal to (>=) 0.048 mg/L.
(C) For systems that use chloramines, ozone,
or chlorine dioxide that meet the criteria specified in 11.8(4)(a)(i)(B), the
supplier must also develop a disinfection profile to determine log inactivation
of viruses.
(ii) If a
supplier plans to make a significant change in disinfection practices, the
supplier must comply with the treatment technique requirement to develop a
disinfection profile to determine log inactivation of Giardia
lamblia and log inactivation of viruses before making the
change.
(iii) "DISINFECTION
PROFILE" means the graphical representation of a system's microbial
inactivation over 12 consecutive months.
(iv) "SIGNIFICANT CHANGES IN DISINFECTION
PRACTICE" means one or more of the following:
(A) Changes to the point of
disinfection.
(B) Changes to the
disinfectant(s) used in the treatment plant.
(C) Changes to the disinfection
process.
(D) Any other modification
identified by the Department.
(b)
Monitoring Requirements for
Disinfection Profiling
(i) To
determine the log inactivation ratio(s) for each disinfection segment before
the distribution system, the supplier must monitor the following set of
parameters during daily peak hourly flow:
(A)
The residual disinfectant concentration(s) (C) at each entry point.
(I) For systems with one point of
disinfectant application and multiple disinfection segments, the supplier must
also monitor before each sequential segment of disinfection.
(II) For systems with multiple points of
disinfectant application, the supplier must also monitor before each additional
point of disinfectant application.
(B) The temperature of the disinfected water
at each residual disinfectant concentration sampling location or at an
alternative Department-approved location(s).
(C) For systems using chlorine, the pH of the
disinfected water at each residual disinfectant concentration sampling location
or at an alternative Department-approved location(s).
(D) System-specific parameters to determine
the disinfectant contact time(s) (T).
(ii) The supplier must monitor the set of
parameters specified in 11.8(4)(b)(i) at the following frequencies:
(A) For systems meeting the criteria as
specified in 11.8(4)(a)(i)(B)(I), at least daily for 12 consecutive
months.
(B) For systems meeting the
criteria as specified in 11.8(4)(a)(i)(B)(II) or 11.8(4)(a)(ii), at least
weekly on the same calendar day for 12 consecutive months.
(C) For seasonal systems, at the frequency
specified above in 11.8(4)(b)(ii)(A) or 11.8(4)(b)(ii)(B) only when the system
operates.
(D) If the supplier
monitors more frequently than required, the monitoring frequency must be evenly
spaced.
(iii) For
systems meeting the criteria specified in 11.8(4)(a)(ii) the supplier is not
required to conduct monitoring as specified in 11.8(4)(b)(i-ii), if the system
meets one of the following criteria:
(A) If
the supplier has at least one year of existing data that are substantially
equivalent to the data set required under 11.8(4)(b)(i-ii), the supplier may
use this data to develop a disinfection profile(s), with the all of the
following conditions:
(I) If the supplier has
made a significant change to treatment practices or changed sources since the
data was collected, the supplier must not use previously collected
data.
(II) The supplier may develop
a disinfection profile(s) using up to three years of existing data.
(B) If the supplier was required
to develop a disinfection profile as specified in 11.8(4)(a)(i)(B), the
supplier may use the previously developed disinfection profile(s) and is not
required to develop a new disinfection profile, with all of the following
conditions:
(I) If the supplier has made a
significant change to treatment practices or changed sources since the
disinfection profile(s) was developed, the supplier must not use a previously
developed disinfection profile(s).
(II) If a virus disinfection profile(s) was
not previously developed, the supplier must develop a virus disinfection
profile(s) using the same monitoring data on which the Giardia
lamblia disinfection profile(s) is based.
(c)
Disinfection Profiling Calculations
(i) For each set of parameters collected
under 11.8(4)(b), the supplier must calculate total inactivation ratio(s) and
total logs of inactivation for Giardia lamblia based on the
CT99.9 values in 11.46 as follows:
(A) The
supplier must determine the total inactivation ratio as follows:
Inactivation ratio is equal to: (CTcalc /CT99.9).
(I) For a supplier monitoring at a single
location, calculate one inactivation ratio.
(II) For a supplier monitoring at multiple
locations:
(a) Determine the inactivation
ratio value for each segment.
(b)
Add all inactivation ratio values to determine the total inactivation ratio:
([SIGMA] (CTcalc /CT99.9)).
(B) The supplier must determine the total
logs of inactivation by multiplying the total inactivation ratio by 3.0.
Total logs of inactivation is equal to: 3.0 x [SIGMA] (CTcalc /CT99.9).
(ii)
If the supplier is required to calculate the logs of inactivation for viruses
as specified in 11.8(4)(a)(i)(C) or 11.8(4)(a)(ii), the supplier must use a
Department-approved calculation method.
(iii) The supplier must maintain disinfection
profile data in graphic form, as a spreadsheet, or in a Department-accepted
format for review as part of sanitary surveys.
(d)
Treatment Technique
Violations and Response for Disinfection Profiling
(i) If the supplier fails to comply with the
requirements specified in this section, 11.8(4), a disinfection profiling
treatment technique violation occurs.
(ii) In the event of a disinfection profile
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.
11.8(5) Disinfection Benchmarking
(a)
Applicability and Definitions for Disinfection
Benchmarking
(i) If the supplier
was required to develop a disinfection profile for Giardia
lamblia and/or viruses as specified in 11.8(4) and plans to make a
significant change in disinfection practices, as defined in 11.8(4)(a)(iv), the
supplier must comply with all of the following treatment technique requirements
before making the change:
(A) Calculate a
disinfection benchmark for each profile developed under 11.8(4)(c).
(B) Consult with the Department.
(ii) "DISINFECTION BENCHMARK"
means the lowest monthly average of total log inactivation values calculated in
the disinfection profile. The disinfection benchmark is used as a baseline of
inactivation when considering changes in the disinfection process.
(b)
Disinfection
Benchmarking Calculations
(i)
The supplier must calculate a disinfection benchmark as follows:
(A) Calculate the average log inactivation
for each month using the total logs of inactivation value(s) calculated in the
disinfection profile developed under 11.8(4)(c).
(B) If the supplier has collected one year of
data, the lowest monthly average log inactivation value is the disinfection
benchmark.
(C) If the supplier has
collected more than one year of data, the average of the lowest monthly average
log inactivation value for each calendar year is the disinfection
benchmark.
(c)
Reporting Requirements for
Department Consultation
(i) The
supplier must submit all of the following information as part of the
consultation process:
(A) A description of the
proposed change in disinfection practice.
(B) The disinfection profile and benchmark
for Giardia lamblia.
(C) If required to be developed, the
disinfection profile and benchmark for viruses.
(D) An analysis of how the proposed change
will affect the current levels of disinfection.
(E) Any additional information requested by
the Department.
(d)
Treatment Technique
Violations and Response for Disinfection Benchmarking
(i) If the supplier fails to comply with the
requirements specified in this section, 11.8(5), a disinfection benchmarking
treatment technique violation occurs.
(ii) In the event of a disinfection benchmark
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.
Disclaimer: These regulations may not be the most recent version. Colorado may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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