| (D) Prior to the effective date of subparagraph (B)
of this paragraph, the combination of disinfection and filtration
processes used by a public water system to treat for Cryptosporidium must achieve at least a
2.0-log removal/inactivation of Cryptosporidium
parvum.
(4) The combination of disinfection and filtration
processes at plants that do not monitor each source in accordance
with the requirements of subsection (b) of this section must achieve
at least a 5.5-log removal/inactivation of Cryptosporidium
parvum.
(5) The executive director may require additional levels
of treatment in cases of poor source water quality.
(6) The executive director may establish minimum design,
operational, and reporting requirements for watershed control programs
and treatment processes used to meet the treatment technique requirements
of this subsection.
(d) Microbial inactivation requirements. A system that
treats surface water or groundwater under the direct influence of
surface water must meet minimum disinfection requirements before the
water is supplied to any consumer.
(1) Inactivation table. The disinfection process must
achieve the minimum microbial inactivation levels shown in the following
table.
Attached Graphic
(A) The disinfection process at treatment plants not
described in the Microbial Inactivation Requirements table must provide
the level of disinfection required by the executive director.
(B) The executive director may require additional levels
of treatment in cases of poor source water quality.
(C) The executive director may reduce the inactivation
requirement for plants that meet the individual filter effluent performance
criteria contained in subsection (g)(1) of this section and have been
assigned a Bin 1 classification under the provisions of subsection
(c)(3) of this section.
(D) A system that fails to meet the inactivation requirements
of this section for a period of longer than four consecutive hours
commits a nonacute treatment technique violation. A system that fails
to conduct the additional testing required by paragraph (2)(C) of
this subsection also commits a nonacute treatment technique violation.
(E) A system that has a plant assigned a Bin 2, 3,
or 4 classification under the provisions of subsection (c)(3) of this
section and uses UV disinfection facilities to meet the treatment
technique requirements for Cryptosporidium must
meet the inactivation requirements of this subsection in at least
95% of the water treated each month.
(2) Monitoring requirements for chemical disinfectants.
Public water systems must monitor the performance of the disinfection
facilities to ensure that appropriate disinfectant levels are maintained.
All monitoring conducted pursuant to the requirements of this subsection
must be conducted at sites designated in the public water system's
monitoring plan.
(A) The disinfectant residual, pH, temperature, and
flow rate of the water in each disinfection zone must be measured
at least once each day during a time when peak hourly raw water flow
rates are occurring.
(B) Disinfection contact time will be based on tracer
study data or a theoretical analysis submitted by the system owner
or their designated agent and approved by the executive director and
the actual flow rate that is occurring at the time that monitoring
occurs.
(C) Treatment plants that fail to demonstrate an appropriate
level of treatment must repeat these tests at four-hour or shorter
intervals until compliance has been reestablished.
(3) Monitoring requirements for UV disinfection facilities.
Public water systems must monitor the performance of the UV disinfection
facilities.
(A) A system must continuously monitor and record UV
intensity as measured by a UV sensor, lamp status, the flow rate through
the unit, and other parameters prescribed by the executive director
to ensure that the units are operating within validated conditions.
(B) A system with a plant that has been assigned a
Bin 2, 3, or 4 classification under the provisions of subsection (c)(3)
of this section must also monitor and record the amount of water treated
by each UV unit each month and the amount of water produced each month
when the unit was not operating within validated conditions.
(4) Analytical requirements. All monitoring required
by this subsection 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).
(A) The pH analysis must be conducted using a pH meter
with a minimum accuracy of plus or minus 0.1 pH units.
(B) The temperature of the water must be measured using
a thermometer or thermocouple with a minimum accuracy of plus or minus
0.5 degrees Celsius.
(C) The free chlorine or chloramine residual (measured
as total chlorine) must be measured to a minimum accuracy of plus
or minus 0.1 milligrams per liter (mg/L). Color comparators may be
used for distribution system samples only. When used, a color comparator
must have current reagents, an unfaded and clear color comparator,
a sample cell that is not discolored or stained, and must be properly
stored in a cool, dark location where it is not subjected to conditions
that would result in staining. The color comparator must be used in
the correct range. If a sample reads at the top of the range, the
sample must be diluted with chlorine-free water, then a reading taken
and the resulting residual calculated.
(D) The chlorine dioxide residual must be measured
to a minimum accuracy of plus or minus 0.05 mg/L using a method that
conforms to the requirements of §290.119 of this title. The DPD-glycine
method using a colorimeter or spectrophotometer may be utilized only
with the written permission of the executive director.
(E) The ozone residual must be measured to a minimum
accuracy of plus or minus 0.05 mg/L using the Indigo Method and using
a colorimeter or spectrophotometer.
(F) The UV dose must be measured by a calibrated sensor
approved by the executive director.
(e) Filtration requirements for conventional filters.
A system that uses granular media filters to treat surface water or
groundwater under the direct influence of surface water must meet
minimum filtration requirements before the water is supplied to any
consumer.
(1) Treatment technique requirements for combined filter
effluent. Treatment plants using conventional media filtration must
meet the following turbidity requirements.
(A) The turbidity level of the combined filter effluent
must never exceed 1.0 nephelometric turbidity unit (NTU).
(B) The turbidity level of the combined filter effluent
must be 0.3 NTU or less in at least 95% of the samples tested each
month.
(2) Performance criteria for individual filter effluent.
The filtration techniques must ensure the public water system meets
the following performance criteria.
(A) The turbidity from each individual filter effluent
should never exceed 1.0 NTU.
(B) At a public water system that serves 10,000 people
or more, the turbidity from each individual filter effluent should
not exceed 0.5 NTU at four hours after the individual filter is returned
to service after backwash or shutdown.
(3) Routine turbidity monitoring requirements. A system
must monitor the performance of its filtration facilities.
(A) A system that serves fewer than 500 people and
continuously monitors the turbidity level of each individual filter
must measure and record the turbidity level of the combined filter
effluent at least once each day that the plant is in operation.
(B) A system that serves at least 500 people and continuously
monitors the turbidity level of each individual filter must measure
and record the turbidity level of the combined filter effluent at
least every four hours that the system serves water to the public.
(C) Except as provided in subparagraph (D) of this
paragraph, a system must continuously monitor the filtered water turbidity
at the effluent of each individual filter and record the turbidity
value every 15 minutes.
(D) A system that serves fewer than 10,000 people and
monitors combined filter effluent turbidity in lieu of individual
filter effluent turbidity under the provisions of §290.42(d)(11)(E)(ii)
of this title (relating to Water Treatment) must:
(i) continuously monitor the turbidity of the combined
filter effluent and record the turbidity value every 15 minutes; and
Cont'd... |
