| (ii) at the lowest method detection limit of the approved
turbidimeter; and
(iii) at the precision and accuracy necessary to determine
compliance with the requirements as described in this subchapter.
(4) Special investigation requirements. A system which
fails to produce water with acceptable turbidity levels, or if the
level of removal/inactivation of pathogens is inadequate or cannot
be determined, the system shall investigate the cause of the problem
and take appropriate corrective action. The executive director can
waive these special monitoring requirements for systems that have
a corrective action schedule approved by the executive director.
(A) A public water system that utilizes membrane filters
for pathogen removal may be required to participate in a special investigation
conducted by the executive director if, during two consecutive months,
the system fails to report all required direct integrity test results
for a specific membrane unit.
(B) A public water system that utilizes membrane filters
for pathogen removal may be required to participate in a special investigation
conducted by the executive director if, during two consecutive months,
a specific membrane unit fails at least one direct integrity test
and continues to produce water.
(C) A public water system may be required to participate
in a special investigation conducted by executive director when documentation
or lack of documentation from a public water system indicates that
the pathogen removal/inactivation levels are inadequate or cannot
be determined.
(g) Other treatment credits for systems in Bins 2 through
4. The executive director may grant additional pathogen removal and
inactivation credit to systems that meet enhanced design, operational,
maintenance, and reporting requirements.
(1) Individual filter effluent. The executive director
may approve an additional 1.0-log removal credit for Giardia and Cryptosporidium
to a treatment plant that uses conventional granular media
filters.
(A) The executive director will approve the additional
credit for a plant if:
(i) the system continuously monitored the filtered
water turbidity at the effluent of each individual filter and recorded
the turbidity value every 15 minutes that the filter was sending water
to the clearwell;
(ii) the turbidity level at each individual filter
effluent is less than or equal to 0.15 NTU in at least 95% of the
measurements recorded during the month; and
(iii) no individual filter produced water with turbidity
level above 0.3 NTU in two consecutive 15-minute readings.
(B) The executive director may also approve the additional
credit for a plant that does not meet the requirements of subparagraph
(A) of this paragraph if:
(i) the executive director determines that the failure
to meet the requirements of subparagraph (A) of this paragraph could
not have been prevented through optimizing plant operations, design,
or maintenance; and
(ii) the system has experienced no more than two such
failures within the most recent 12 months.
(2) Combined filter effluent. The executive director
may approve an additional 0.5-log removal credit for Cryptosporidium to a treatment plant that
uses conventional granular media filters if:
(A) the system continuously monitored the filtered
water turbidity at the effluent of each individual filter and recorded
the turbidity value every 15 minutes that the filter was sending water
to the clearwell;
(B) the turbidity level at the combined filter effluent
is less than or equal to 0.15 NTU in at least 95% of the measurements
recorded during the month; and
(C) the plant does not receive additional treatment
credit under paragraph (1) of this subsection.
(3) Second stage filtration. The executive director
will approve an additional 0.5-log removal credit for Giardia and Cryptosporidium
to a treatment plant that uses a second, separate stage of
conventional granular media filters if:
(A) the filters in both stages meet minimum design
criteria approved by the executive director;
(B) all of the water produced by the plant passes through
both stages of filtration;
(C) the system continuously monitored the filtered
water turbidity at the effluent of each individual filter in the first
stage of filtration and recorded the turbidity value every 15 minutes
that the filter was sending water to the clearwell; and
(D) no individual filter in the first stage of filtration
produced water with turbidity level above 1.0 NTU in two consecutive
15-minute readings.
(4) Other pathogen control strategies. The executive
director may approve an additional removal or inactivation credit
for other pre-filtration, filtration, or post-filtration strategies
that can demonstrate effective, consistent levels of enhanced pathogen
control.
(A) The alternative strategy must achieve a quantifiable
reduction in the risk of waterborne disease in all of the treated
water produced by the plant.
(B) The alternative strategy must conform to any applicable
requirement of 40 CFR §§141.715 - 141.720.
(C) The executive director may establish minimum site-specific
design, operational, maintenance, and reporting requirements for any
alternative strategy used to meet minimum treatment technique requirements
of subsection (c) of this section.
(D) The executive director may not approve additional
removal credit under the provisions of this paragraph to any strategy
that includes a treatment process has been assigned additional removal
or inactivation credit under any other provision of this subsection.
(h) Reporting requirements. Public water systems must
properly complete and submit periodic reports to demonstrate compliance
with this section.
(1) A system that has a turbidity level exceeding 1.0
NTU in the combined filter effluent must consult with the executive
director within 24 hours.
(2) A system that treats surface water sources or groundwater
sources under the direct influence of surface water must submit a
Surface Water Monthly Operating Report each month for each plant.
(A) A system that uses alternative treatment technologies
or has been assigned a Bin 2, Bin 3, or Bin 4 classification under
subsection (c)(3)(B) of this section must submit a Surface Water Monthly
Operating Report (commission Form 0102D) for alternative technologies.
(B) A system that continuously monitors the performance
of individual filters, but is not required to submit commission Form
0102D, must submit a Surface Water Monthly Operating Report (commission
Form 0102C).
(C) A system that is allowed by the executive director
to submit combined filter effluent turbidity in lieu of individual
filter effluent turbidity under §290.42(d)(11)(E)(ii) of this
title must submit a Surface Water Monthly Operational Report for Plants
That Do Not Have a Turbidimeter on Each Filter (commission Form 0103)
each month for each plant that treats surface water or groundwater
under the direct influence of surface water.
(3) A system that must complete the additional monitoring
required by subsection (e)(4)(A)(i) or (B)(i) of this section must
submit a Filter Profile Report for Individual Filters (commission
Form 10276) with its Surface Water Monthly Operating Report.
(4) A system that must complete the additional monitoring
required by subsection (e)(4)(A)(ii) or (B)(ii) of this section must
submit a Filter Assessment Report for Individual Filters (commission
Form 10277) with its Surface Water Monthly Operating Report.
(5) A system that must complete the additional monitoring
required by subsection (e)(4)(A)(iii) or (B)(iii) of this section
must submit a Comprehensive Performance Evaluation Request Form (commission
Form 10278) with its Surface Water Monthly Operating Report.
(6) A system must submit any additional reports required
by the executive director to verify the level of pathogen removal
or inactivation achieved by the system's treatment plants.
(7) A system must submit its Cryptosporidium
bin classification.
(8) A system must submit reports required by subsection
(b)(7) of this section.
(9) Periodic reports required by this section must
be submitted to the Water Supply Division, Texas Commission on Environmental
Quality, MC 155, P.O. Box 13087, Austin, Texas 78711-3087 by the tenth
day of the month following the end of the reporting period.
(i) Compliance determination. Compliance with the requirements
of this section must be determined using the criteria of this subsection.
(1) A public water system that fails to complete source
water monitoring or conduct the routine monitoring tests and any applicable
special investigations required by this section commits a monitoring
violation.
Cont'd... |
