Ga. Comp. R. & Regs. R. 391-3-5-.20 - Turbidity Sampling and Analytical Requirements
(1)
Turbidity Testing Frequency.
On and after June 29, 1993, representative samples of filtered water shall be
taken and analyzed by said suppliers at least every four hours when the plant
is in operation, for the purpose of making turbidity measurements to determine
compliance with the treatment technique requirement of Rule
391-3-5-.18(3). If
the Division determines that a reduced sampling frequency in a non-community
system will not pose a risk to public health, it can reduce the required
sampling frequency in accordance with
40 CFR
141.74 for systems using slow sand filtration
or filtration treatment other than conventional treatment, direct filtration,
or diatomaceous earth filtration. The option of reducing the turbidity
frequency shall be permitted only in those public water systems that practice
disinfection and which maintain an active residual disinfectant in the
distribution system and in those cases where the Division has indicated in
writing that no unreasonable risk to health existed under the circumstances of
this option. The turbidity measurements shall be made in accordance with the
recommendations set forth in 40 CFR Part 141 .22.
(2)
Exceedance Determination. If
a turbidity treatment violation has occurred based on a single exceedance of
the maximum allowable turbidity limit, the supplier of water shall consult with
the Division as soon as practical but no later than 24 hours after learning of
the violation (40 CFR
141.203(b)). If the
consultation does not occur within those 24 hours, the violation is elevated to
Tier 1 under 40 CFR Subpart Q. If the monthly treatment technique requirement
is exceeded, or if any measured turbidity level exceeds the maximum allowable
level, the supplier of water shall report to the Division and notify the public
as directed in Rules
391-3-5-.30 and
.32.
(3)
Applicability to Surface Water
Sources. The requirements of this Rule shall apply only to public water
systems, which use water obtained in whole or in part from surface water
sources or ground water sources under the direct influence of surface
water.
(4)
Compliance and
Enforcement. The Division has the authority to determine compliance or
initiate enforcement action based upon analytical results or other information
compiled by their sanctioned representatives or agencies.
(5)
Filtration Requirements for Greater
than 10,000 Population Water Systems. Beginning January 1, 2002, public
water systems that use surface water or ground water under the direct influence
of surface water and serve at least 10,000 people must meet the filtration
requirements specified in 40
CFR §
141.173.
(6)
Enhanced Filtration
Requirements. The Enhanced Filtration and Disinfection requirements
specified in 40 CFR, Subpart P are applicable to Subpart H systems serving at
least 10,000 people.
(a) General requirements:
40 CFR, Subpart P §
141.170 is hereby incorporated by reference.
Subpart H systems that did not conduct optional monitoring under § 141.172
because they served fewer than 10,000 persons when such monitoring was
required, but serve more than 10,000 persons prior to January 14, 2005 must
comply with §
§ 141.170, 141.171, 141.173, 141.174, and 141.175.
These systems must contact the Division and establish a disinfection benchmark.
A system that decides to make a significant change to its disinfection
practice, as described in § 141.172(c)(1)(i) through (iv) must obtain
prior approval from the Division prior to making such change.
(b) Criteria for avoiding filtration:
40 CFR, Subpart P §
141.171 is hereby incorporated by
reference.
(c) Disinfection
profiling and benchmarking: 40 CFR, Subpart P §
141.172
is hereby incorporated by reference.
(d) Determination of systems required to
profile: 40 CFR, Subpart P
§
141.172(a) is hereby
incorporated by reference.
(e)
Disinfection profiling: 40
CFR, Subpart P §
141.172(b) is hereby
incorporated by reference.
(f)
Disinfection benchmarking: 40 CFR, Subpart P §
141.172(c) is hereby
incorporated by reference.
(7)
Filtration.
40 CFR, Subpart P §
141.173 is hereby incorporated by reference.
(a) Conventional filtration treatment or
direct filtration: 40 CFR,
Subpart P §
141.173(a)
is hereby incorporated by reference. (For systems using conventional filtration
or direct filtration, the turbidity level of representative samples of a
system's filtered water must be less than or equal to 0.3 NTU (Nephelometric
Turbidity Units) in at least 95 percent of the measurements taken each month,
measured as specified in 40
CFR §
141.74(a) and
(c), and the turbidity level of
representative samples of a system's filtered water must at no time exceed 1
NTU, measured as specified in
40 CFR §
141.74(a) and
(c)).
(b) Systems using filtration technologies
other than conventional filtration treatment, direct filtration, slow sand
filtration, or diatomaceous earth filtration:
40 CFR, Subpart P §
141.173(b) is hereby
incorporated by reference. Beginning January 1, 2002, systems serving at least
10,000 people must meet the requirements for other filtration technologies
referenced in 141.173(b).
(c)
Filtration sampling requirements:
40 CFR, Subpart P §
141.174 is hereby incorporated by reference.
(A public water system subject to the requirements of this section that
provides conventional filtration treatment or direct filtration must conduct
continuous monitoring of turbidity for each individual filter using an approved
method in 40 CFR §
141.74(a) and must calibrate
turbidimeters using the procedure specified by the manufacturer. Systems must
record the results of individual filter monitoring every fifteen (15) minutes.
If there is a failure in the continuous turbidity monitoring equipment, the
system must conduct grab sampling every four (4) hours in lieu of continuous
monitoring, but for no more than five (5) working days following the failure of
the equipment.)
(8)
Filtration Requirements for Fewer than 10,000 Population Water
Systems. Beginning January 14, 2005, public water systems that use
surface water or ground water under the direct influence of surface water as a
source and serve fewer than 10,000 people must meet the filtration and
disinfection requirements in 40 CFR Part 141, Subpart T. This requirement is in
addition to complying with requirements in Subpart H of 40 CFR Part 141.
(a) Beginning January 14, 2005, public water
systems that use surface water or ground water under the direct influence of
surface water and serve fewer than 10,000 people must meet the filtration
requirements specified in 40
CFR §§
141.550 through
141.553.
(b) Other filtration technologies:
40 CFR §
141.73(d) is hereby
incorporated by reference. Beginning January 14, 2005, systems serving fewer
than 10,000 people must meet the requirements for other filtration technologies
in 40 CFR §§
141.550 through
141.553.
(c) General requirements:
40 CFR, Subpart T §
141.500 is hereby incorporated by
reference.
(d) Additional watershed
control requirements for unfiltered systems:
40 CFR, Subpart T
§§
141.520 through
141.522 is hereby incorporated by
reference. This is in addition to the continued requirement to comply with the
filtration avoidance criteria in
40 CFR §
141.71.
(e) Disinfection Profile:
40 CFR, Subpart T
§§
141.530 through
141.536 is hereby incorporated by
reference. This requirement applies both to community and non-transient
non-community water systems.
(f)
Disinfection benchmark: 40
CFR, Subpart T §§
141.540 through
141.544 is hereby incorporated by
reference. If you are a subpart H system required to develop a disinfection
profile under Rule
391-3-5-.20(10)(e),
your system must develop a disinfection benchmark if you decide to make a
significant change to your disinfection practice. Before implementing a
significant disinfection practice change, a prior approval from the Division
must be obtained. Significant changes to disinfection practice include:
1. Changes to the point of
disinfection;
2. Changes to the
disinfectant(s) used in the treatment plant;
3. Changes to the disinfection process;
or
4. Any other modification
identified by the Division.
(g) Combined filter effluent requirements:
40 CFR, Subpart T §
141.550 through
141.553 is hereby incorporated by
reference. This requirement applies to all subpart H systems which serve
populations fewer than 10,000, are required to filter, and utilize filtration
other than slow sand filtration or diatomaceous earth filtration.
1. For systems using conventional filtration
or direct filtration, the turbidity level of representative samples of a
system's filtered water must be less than or equal to 0.3 NTU in at least 95
percent of the measurements taken each month, and the maximum turbidity level
of representative samples of a system's filtered water must at no time exceed 1
NTU. All measurements must be taken as described in
40 CFR §
141.74(a) and (c).
2. For systems using "alternative" filtration
(filtration other than slow sand filtration, diatomaceous earth filtration,
conventional filtration, or direct filtration), the 95th percentile turbidity
value, not to exceed 1 NTU, and the maximum turbidity value, not to exceed 5
NTU, shall be determined by the Division based on the demonstration as
described in 40 CFR, Subpart
T §
141.552. The systems, using pilot
plant studies or other means, must demonstrate that the system's filtration, in
combination with disinfection treatment, consistently achieves: two-log (99%)
removal of Cryptosporidium oocysts; three-log (99.9%) removal and/or
inactivation of Giardia lamblia cysts; and four-log (99.99%) removal and/or
inactivation of viruses.
(h) Individual filter turbidity requirements
for systems utilizing conventional filtration or direct filtration:
40 CFR, Subpart T
§§
141.560 through
141.564 is hereby incorporated by
reference. A subpart H public water system subject to the requirements of this
Rule must conduct continuous monitoring of turbidity for each individual filter
using an approved method in 40 CFR §
141.74(a) and must calibrate
turbidimeters using the procedure specified by the manufacturer. Systems must
record the results of individual filter monitoring every fifteen (15) minutes.
If there is a failure in the continuous turbidity monitoring equipment, the
system must conduct grab sampling every four (4) hours in lieu of continuous
monitoring until the turbidimeter is back on-line. The system has fourteen (14)
days to resume continuous monitoring before a violation is incurred.
1. Systems with two or fewer filters may
conduct continuous monitoring of combined filter effluent turbidity in lieu of
individual filter effluent turbidity monitoring, in accordance with the same
requirements set forth in 40
CFR §
141.560(a) through
(d) and §
141.561.
2. Based on continuous turbidity monitoring
of individual filters, the systems are required to take the follow-up actions
described in 40 CFR §
141.563(a), (b) and
(c).
(i) Reporting and recordkeeping requirements:
40 CFR, Subpart T
§§
141.570 through
141.571 is hereby incorporated by
reference. The items which must be reported and the frequency of reporting must
be as specified in 40 CFR
§
141.570. Based on the requirements of
subpart T of 40 CFR Part 141, applicable systems must keep several required
records, in addition to the recordkeeping required under
40 CFR §
141.75. Specifically, the results of
individual filter monitoring must be kept for at least three (3) years and the
results of any disinfection profiling or benchmarking (including raw data and
analysis) must be kept indefinitely.
Notes
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