| (a) Applicability. A water treatment plant must meet
the provisions of this section if the plant:
(1) serves a community or nontransient, noncommunity
public water system;
(2) treats surface water or groundwater under the direct
influence of surface water; and
(3) uses a series of treatment processes that includes
coagulation, flocculation, sedimentation or clarification, and filtration
as part of the overall treatment protocol.
(b) Treatment technique. Systems must achieve the Step
1 removal requirements in paragraph (1) of this subsection, meet one
of the alternative compliance criteria described in paragraph (2)
of this subsection, or apply for the alternative Step 2 removal requirements
described in paragraph (3) of this subsection.
(1) Systems must determine their ability to meet the
Step 1 removal requirements given in the following table. A water
treatment plant's Step 1 total organic carbon (TOC) required percent
removal is based upon plant's source water TOC and alkalinity. Step
1 TOC percent removal requirements are indicated in the following
table. Systems practicing softening are evaluated based on the Step
1 TOC removal in the far-right column (Source water alkalinity >120
milligrams per liter (mg/L)) for the specified source water TOC.
Attached Graphic
(2) Systems may determine their ability to meet one
of the eight alternative compliance criteria listed in this paragraph.
(A) A system meets alternative compliance criteria
Number 1 if the system's source water TOC level is less than 2.0 mg/L,
calculated quarterly as a running annual average.
(B) A system meets alternative compliance criteria
Number 2 if the system's treated water TOC level is less than 2.0
mg/L, calculated quarterly as a running annual average.
(C) A system meets alternative compliance criteria
Number 3 if: the system's source water TOC level is less than 4.0
mg/L, calculated quarterly as a running annual average; the source
water alkalinity is greater than 60 mg/L (as calcium carbonate (CaCO3),
calculated quarterly as a running annual average; and the total trihalomethanes
(TTHM) and haloacetic acid-group of five (HAA5) running annual averages
are no greater than 0.040 mg/L and 0.030 mg/L, respectively.
(D) The system meets alternative compliance criteria
Number 4 if the TTHM and HAA5 running annual averages are no greater
than 0.040 mg/L and 0.030 mg/L, respectively, and the system uses
only chlorine for primary disinfection and maintenance of a residual
in the distribution system.
(E) The system meets alternative compliance criteria
Number 5 if the system's source water specific ultraviolet absorbance
(SUVA), prior to any treatment, measured monthly, is less than or
equal to 2.0 liters per milligram-meter (L/mg-m), calculated quarterly
as a running annual average.
(F) The system meets alternative compliance criteria
Number 6 if the system's finished water SUVA, measured monthly at
a point prior to any disinfection, is less than or equal to 2.0 L/mg-m,
calculated quarterly as a running annual average.
(G) The system meets alternative compliance criteria
Number 7 if the system practices softening, cannot achieve the Step
1 TOC removals required by paragraph (1) of this subsection, and has
treated water alkalinity less than 60 mg/L (as CaCO3) and calculated
quarterly as a running annual average.
(H) The system meets alternative compliance criteria
Number 8 if the system practices softening, cannot achieve the Step
1 TOC removals required by paragraph (1) of this subsection, and has
magnesium hardness removal greater than or equal to 10 mg/L (as CaCO3),
measured monthly calculated quarterly as a running annual average.
(3) If a system fails to meet the Step 1 TOC removal
requirement required by paragraph (1) of this subsection and does
not meet one of eight alternative compliance criteria described in
paragraph (2) of this subsection, the system must apply to the executive
director for approval of Step 2 removal requirements.
(A) The plant must perform Step 2 jar testing to determine
the coagulant dose at which the removal of TOC is less than 0.3 mg/L
for an increase in coagulant of 10 mg/L alum or its equivalent. This
dose is referred to as the point of diminishing returns (PODR).
(B) The system must submit the results of the Step
2 jar testing to the executive director for approval of the alternative
removal requirements at least 15 days before the end of the applicable
quarter.
(C) The executive director may approve Step 2 alternative
removal requirements.
(i) If approved, the removal achieved at the PODR becomes
the alternative full-scale TOC removal requirement for the plant.
(ii) The alternate removal requirements may be applied
to the quarter in which the jar test results are received and for
the following quarter.
(c) TOC monitoring requirements. Systems must conduct
required TOC monitoring during normal operating conditions at sites
and at the frequency designated in the system's monitoring plan.
(1) Systems must monitor for TOC and alkalinity in
the source water prior to any treatment. Between one and eight hours
after taking the source water sample, systems must measure each treatment
plant TOC after filtration in the combined filter effluent stream.
These samples (source water alkalinity, source water TOC, and treated
water TOC) are referred to as a TOC sample set.
(2) Systems must take one TOC sample set monthly (every
30 days) at a time representative of normal operating conditions and
influent water quality. With the executive director's approval, a
system may reduce monitoring according to subparagraphs (A) - (C)
of this paragraph.
(A) Systems with a running annual average treated water
TOC of less than 2.0 mg/L for two consecutive years may reduce monitoring
to one TOC sample set per plant per quarter (every 90 days). The system
must revert to routine monitoring in the month following the quarter
when the running annual average treated water TOC is greater than
or equal to 2.0 mg/L.
(B) Systems with a running annual average treated water
TOC of less than 1.0 mg/L for one year may reduce monitoring to one
TOC sample set per plant per quarter (every 90 days). The system must
revert to routine monitoring in the month following the quarter when
the running annual average treated water TOC is greater than or equal
to 2.0 mg/L.
(C) Systems with a running annual average source water
TOC at each plant of less than or equal to 4.0 mg/L based on the running
annual average of the most recent four quarters of monitoring may
reduce source TOC monitoring to one source TOC sample per quarter
(every 90 days) if they also meet criteria for reduced disinfection
byproduct monitoring. In order to remain on quarterly source TOC monitoring,
the system must also meet the criteria for reduced trihalomethane
and haloacetic acid monitoring given in §290.113(c)(4) of this
title (relating to Stage 1 Disinfection Byproducts (TTHM and HAA5))
until the date shown in table §290.113(a)(2) of this title. After
the date shown in §290.115(a)(2) of this title (relating to Stage
2 Disinfection Byproducts (TTHM and HAA5)), the system must also meet
the criteria for reduced trihalomethane and haloacetic acid monitoring
in §290.115(c)(3) of this title in order to remain on quarterly
source TOC monitoring. The system must revert to routine monitoring
in the first month following the quarter when the running annual average
source water TOC is greater than 4.0 mg/L, or the system no longer
meets the reduced monitoring criteria for disinfection byproducts.
(3) A public water system attempting to meet the treatment
technique requirements for TOC using alternative compliance criteria
Number 5 (as defined in subsection (b)(2)(E) of this section) must
monitor for SUVA in the source water prior to any treatment at least
once each month.
(4) A public water system attempting to meet the treatment
technique requirements for TOC using alternative compliance criteria
Number 7 (as defined in subsection (b)(2)(G) of this section) must
monitor for alkalinity in the treated water at any point prior to
distribution system at least once each month.
(5) A public water system attempting to meet the treatment
technique requirements for TOC using alternative compliance criteria
Number 8 (as defined in subsection (b)(2)(H) of this section) must
monitor for magnesium in both the source water prior to any treatment
at and the treated water at any point prior to the distribution system
least once each month.
(d) Analytical requirements for TOC treatment. Analytical
procedures required by this section must be conducted at a facility
approved by the executive director and using methods that conform
to the requirements of §290.119 of this title (relating to Analytical
Procedures).
Cont'd... |
