Indiana Administrative Code
Title 327 - WATER POLLUTION CONTROL DIVISION
Article 8 - PUBLIC WATER SUPPLY
Rule 2.5 - Disinfectants and Disinfection
Section 2.5-9 - Treatment techniques for control of disinfection byproducts precursors
Universal Citation: 327 IN Admin Code 2.5-9
Current through September 18, 2024
Authority: IC 13-13-5-1; IC 13-14-8-2; IC 13-14-8-7; IC 13-18-3-2
Affected: IC 13-12-3-1; IC 13-13-5-2; IC 13-14-9; IC 13-18-11
Sec. 9.
(a) Applicability is as follows:
(1) Subpart H
systems using conventional filtration treatment shall operate with enhanced
coagulation or enhanced softening to achieve the TOC percent removal levels
specified in subsection (b) unless the system meets at least one (1) of the
alternative compliance criteria listed in subdivision (2) or (3).
(2) Subpart H systems using conventional
filtration treatment may use one (1) or more of the following alternative
compliance criteria to comply with this section instead of complying with
subsection (b):
(A) The system's source water
TOC level, measured according to section 5(d)(3) of this rule, is less than two
and zero-tenths (2.0) milligrams per liter, calculated quarterly as a running
annual average.
(B) The system's
treated water TOC level, measured according to section 5(d)(3) of this rule, is
less than two and zero-tenths (2.0) milligrams per liter, calculated quarterly
as a running annual average.
(C)
The system's source water TOC level, measured according to section 5(d)(3) of
this rule, is less than four and zero-tenths (4.0) milligrams per liter,
calculated quarterly as a running annual average and the following are met:
(i) The source water alkalinity, measured
according to section 5(d)(1) of this rule, is greater than sixty (60)
milligrams per liter (as CaCO3), calculated quarterly as
a running annual average.
(ii)
Either of the following:
(AA) The TTHM and
HAA5 running annual averages are no greater than forty-thousandths (0.040)
milligram per liter and thirty-thousandths (0.030) milligram per liter,
respectively.
(BB) Before the
effective date for compliance in section 4(b) of this rule, the system has made
a clear and irrevocable financial commitment not later than the effective date
for compliance in section 4(b) of this rule to use technologies that will limit
the levels of TTHMs and HAA5 to not more than forty-thousandths (0.040)
milligram per liter and thirty-thousandths (0.030) milligram per liter,
respectively. Systems shall submit evidence of a clear and irrevocable
financial commitment, in addition to a schedule containing milestones and
periodic progress reports for installation and operation of appropriate
technologies, to the commissioner for approval not later than the effective
date for compliance in section 4(b) of this rule. These technologies must be
installed and operating not later than June 30, 2005.
(D) The TTHM and HAA5 running annual averages
are not greater than forty-thousandths (0.040) milligram per liter and
thirty-thousandths (0.030) milligram per liter, respectively, and the system
uses only chlorine for primary disinfection and maintenance of a residual in
the distribution system.
(E) The
system's source water SUVA, before any treatment and measured monthly according
to section 5(d)(4) of this rule, is less than or equal to two and zero-tenths
(2.0) liters per milligram meter, calculated quarterly as a running annual
average.
(F) The system's finished
water SUVA, measured monthly according to section 5(d)(4) of this rule, is less
than or equal to two and zero-tenths (2.0) liters per milligram meter,
calculated quarterly as a running annual average.
(3) Systems practicing
enhanced softening that cannot achieve the TOC removals required by subsection
(b)(2) may use the following alternative compliance criteria instead of
complying with subsection (b):
(A) Softening
that results in lowering the treated water alkalinity to less than sixty (60)
milligrams per liter (as CaCO3), measured monthly
according to section 5(d)(1) of this rule and calculated quarterly as a running
annual average.
(B) Softening that
results in removing at least ten (10) milligrams per liter of magnesium
hardness (as CaCO3), measured monthly according to
section 5(d)(5) of this rule and calculated quarterly as an annual running
average.
Systems shall comply with monitoring requirements in section 6(d) of this rule.
(b) Enhanced coagulation and enhanced softening performance requirements are as follows:
(1) Systems shall achieve the percent
reduction of TOC specified in subdivision (2) between the source water and the
combined filter effluent unless the commissioner approves a system's request
for alternate minimum TOC removal (Step 2) requirements under subdivision
(3).
(2) Required Step 1 TOC
reductions, indicated in the following table, are based upon specified source
water parameters measured in accordance with section 6(d) of this rule. Systems
practicing softening are required to meet the Step 1 TOC reductions in the far
right column (source water alkalinity greater than one hundred twenty (120)
milligrams per liter) for the specified source water TOC:
Step 1 Required Removal of TOC by Enhanced Coagulation and Enhanced Softening for Subpart H Systems Using Conventional Treatment1, 2
| Source-Water Alkalinity, mg/L as CaCO3 | |||
| Source-Water TOC, mg/L | 0-60 | >60-120 | >1203 |
| >2.0-4.0 | 35.0% | 25.0% | 15.0% |
| >4.0-8.0 | 45.0% | 35.0% | 25.0% |
| >8.0 | 50.0% | 40.0% | 30.0% |
1 Systems
meeting at least one (1) of the conditions in subsection (a)(2) are not
required to operate with enhanced coagulation.
2Softening systems meeting one (1) of
the alternative compliance criteria in subsection (a)(3) are not required to
operate with enhanced softening.
3
Systems practicing softening shall meet the TOC removal requirements in this
column.
(3) Subpart H
conventional treatment systems that cannot achieve the Step 1 TOC removals
required by subdivision (2) due to water quality parameters or operational
constraints shall comply with the following regarding alternate minimum TOC
(Step 2) removal:
(A) The system shall apply
to the commissioner, within three (3) months of failure to achieve the TOC
removals required by subdivision (2), for approval of alternate minimum TOC
(Step 2) removal requirements submitted by the system as provided by
subdivision (4).
(B) If the
commissioner approves the alternate minimum TOC removal (Step 2) requirements,
the commissioner may make those requirements retroactive for the purposes of
determining compliance. Until the commissioner approves the alternate minimum
TOC removal (Step 2) requirements, the system shall meet the Step 1 TOC
removals contained in subdivision (2).
(4) Alternate minimum TOC removal (Step 2)
requirements are as follows:
(A) Applications
made to the commissioner by enhanced coagulation systems for approval of
alternate minimum TOC removal (Step 2) requirements under subdivision (3) must
include, at a minimum, results of bench-scale or pilot-scale testing conducted
under clause (C). The submitted bench-scale or pilot-scale testing will be used
to determine the alternate enhanced coagulation level.
(B) As used in this subdivision, "alternate
enhanced coagulation level" is described by the following sequential process:
(i) The term means coagulation at a coagulant
dose and pH as determined by the method described in clause (A), this clause,
and clauses (C) through (E) such that an incremental addition of ten (10)
milligrams per liter of alum (or equivalent amount of ferric salt) results in a
TOC removal of less than or equal to three-tenths (0.3) milligram per
liter.
(ii) The percent removal of
TOC calculated under item (i) on the TOC removal versus coagulant dose curve is
defined as the minimum TOC removal required for the system.
(iii) Once approved by the commissioner, the
minimum TOC removal requirement calculated under item (ii):
(AA) supersedes the minimum TOC removal
required by the table in subdivision (2); and
(BB) will be effective until the commissioner
approves a new value based on the results of a new bench-scale and pilot-scale
tests.
Failure to achieve alternate minimum TOC removal levels is a violation of this subsection.
(C) Bench-scale or pilot-scale testing of
enhanced coagulation must be conducted by using representative water samples
and adding ten (10) milligrams per liter increments of alum, or equivalent
amounts of ferric salt, until the pH is reduced to a level less than or equal
to the enhanced coagulation Step 2 target pH shown in the following table:
| Enhanced Coagulation Step 2 Target pH | |
| Alkalinity (mg/L as CaCO3) | Target pH |
| 0-60 | 5.5 |
| >60-120 | 6.3 |
| >120-240 | 7.0 |
| >240 | 7.5 |
(D)
For waters with alkalinities of less than sixty (60) milligrams per liter for
which the addition of small amounts of alum or equivalent addition of iron
coagulant drives the pH below five and five-tenths (5.5) before significant TOC
removal occurs, the system shall add necessary chemicals to maintain the pH
between five and three-tenths (5.3) and five and seven-tenths (5.7) in samples
until the TOC removal of three-tenths (0.3) milligram per liter per ten (10)
milligrams per liter alum added, or equivalent addition of iron coagulant, is
reached.
(E) The system may operate
at any coagulant dose or pH necessary, consistent with, the provisions of 327
IAC 8-2, 327 IAC 8-2.5, and 327 IAC 8-2.6, to achieve the minimum TOC percent
removal approved under subdivision (3).
(F) If the TOC removal is consistently less
than three-tenths (0.3) milligram per liter of TOC per ten (10) milligrams per
liter of incremental alum dose at all dosages of alum (or equivalent addition
of iron coagulant), then the:
(i) water is
deemed to contain TOC not amenable to enhanced coagulation; and
(ii) system may apply to the commissioner for
a waiver of enhanced coagulation requirements.
(c) Compliance calculations are required as follows:
(1) Subpart H systems other than those
identified in subsection (a)(2) or (a)(3) shall comply with requirements
contained in subsection (b)(2) or (b)(3). Systems shall calculate compliance
quarterly, beginning after the system has collected twelve (12) months of data,
by determining an annual average using the following method:
STEP 1: Calculate actual monthly TOC percent removal, which is equal to: (1 - (treated water TOC/source water TOC)) one hundred (100).
STEP 2: Calculate the required monthly TOC percent removal (from either the table in subsection (b)(2) or from subsection (b)(3)).
STEP 3: Divide the value determined under STEP 1 by the value determined under STEP 2.
STEP 4: Add together the quotients determined under STEP 3 for the last twelve (12) months and divide by twelve (12).
STEP 5: If the quotient calculated in STEP 4 is less than one and zero-hundredths (1.00), the system is not in compliance with the TOC percent removal requirements.
(2) Systems may use one (1) or more of the
following provisions instead of the calculations in subdivision (1) to
determine compliance with TOC percent removal requirements:
(A) In any month that the system's treated or
source water TOC level, measured according to section 5(d)(3) of this rule, is
less than two and zero-tenths (2.0) milligrams per liter, the system may assign
a monthly value of one and zero-tenths (1.0) (instead of the value calculated
in STEP 3 of subdivision (1)) when calculating compliance under subdivision
(1).
(B) In any month that a system
practicing softening removes at least ten (10) milligrams per liter of
magnesium hardness (as CaCO3), the system may assign a
monthly value of one and zero-tenths (1.0) (instead of the value calculated in
STEP 3 of subdivision (1)) when calculating compliance under subdivision
(1).
(C) In any month that the
system's source water SUVA, before any treatment and measured according to
section 5(d)(4) of this rule, is less than or equal to two and zero-tenths
(2.0) liters per milligram meter, the system may assign a monthly value of one
and zero-tenths (1.0) (instead of the value calculated in STEP 3 of subdivision
(1)) when calculating compliance under subdivision (1).
(D) In any month that the system's finished
water SUVA, measured according to section 5(d)(4) of this rule, is less than or
equal to two and zero-tenths (2.0) liters per milligram meter, the system may
assign a monthly value of one and zero-tenths (1.0) (instead of the value
calculated in STEP 3 of subdivision (1)) when calculating compliance under
subdivision (1).
(E) In any month
that a system practicing enhanced softening lowers alkalinity below sixty (60)
milligrams per liter (as CaCO3), the system may assign a
monthly value of one and zero-tenths (1.0) (instead of the value calculated in
STEP 3 of subdivision (1)) when calculating compliance under subdivision
(1).
(3) Subpart H
systems using conventional treatment may also comply with this section by
meeting the criteria in subsection (a)(2) or (a)(3).
(d) The commissioner identifies the following as treatment techniques for Subpart H systems using conventional treatment to control the level of disinfection byproduct precursors in drinking water treatment and distribution systems:
(1)
Enhanced coagulation.
(2) Enhanced
softening.
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