| (C) Continuous turbidity monitoring must be conducted
using a continuous, on-line turbidimeter and a device that records
the turbidity level reading at least once every 15 minutes.
(i) Turbidity data may be recorded electronically by
a supervisory control and data acquisition system (SCADA) or on a
strip chart. The recorder must be designed so that the operator can
accurately determine the turbidity level readings at 15-minute intervals.
(ii) If there is a failure in the continuous turbidity
monitoring equipment at a system serving 10,000 people or more, the
system must conduct grab sampling every four hours in lieu of continuous
monitoring, but for no more than five working days following the failure
of the equipment.
(iii) If the continuous turbidity monitoring equipment
at a system serving fewer than 10,000 people malfunctions, the system
must conduct grab sampling every four hours in lieu of continuous
monitoring, but for no more than 14 working days following the failure
of the equipment.
(D) A system that monitors combined filter effluent
turbidity in lieu of individual filter effluent turbidity under §290.42(d)(11)(E)(ii)
of this title must monitor the performance of individual filters using
a bench-top turbidimeter.
(E) Combined filter effluent and individual filter
effluent turbidity monitoring equipment and all associated data recording
devices shall read and record turbidity levels to adequately determine
compliance with the requirements as described in this subchapter.
The turbidity equipment and all associated recording devices shall
read and record levels:
(i) at least 10% higher than the turbidity level needed
to determine compliance with the highest applicable regulatory requirement
as described in this subchapter;
(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.
(f) Filtration requirements for other filters. A system
that uses cartridge filters, membrane filters, or other unconventional
filtration systems 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. A system that
uses unconventional filtration technologies such as membrane filters
or cartridge filters must meet treatment technique requirements prescribed
by the executive director.
(A) The filtration facilities must meet combined filter
effluent and individual filter effluent turbidity limits established
by the executive director.
(B) The filtration facilities must be operated and
maintained in accordance with requirements that the executive director
determines are needed to demonstrate the amount of Giardia and Cryptosporidium
removal achieved.
(2) 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 cartridge
or membrane unit must measure and record the turbidity level of the
combined 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 cartridge or membrane
unit must measure and record the turbidity level of the combined effluent
at least every four hours that the system serves water to the public.
(C) A system using membranes must use a method approved
by the executive director to continuously monitor the quality of the
water produced by each membrane unit and record the monitoring results
at least once every five minutes. The executive director may approve
monitoring parameters other than turbidity and decrease the frequency
to once every 15 minutes if the approved operating parameters will
allow consecutive readings to be obtained between backwash or backflush
cycles.
(D) A system using membranes must conduct direct integrity
testing on each membrane unit using a procedure approved by the executive
director.
(i) Direct integrity tests must be conducted in a manner
that will detect a membrane defect of 3 microns or smaller and demonstrates
a removal efficiency equal to or greater than the removal credit awarded
to the membrane filtration process by the executive director.
(ii) Direct integrity test method must calculate the
log removal value for a 3-micron size particle and establish an upper
control limit which assures that the unit is capable of meeting the
removal credit approved by the executive director.
(iii) A system that has been assigned a Bin 1 classification
under the provisions of subsection (c)(3)(B) of this section must
conduct direct integrity tests at least once every seven days. The
executive director may reduce the testing requirements for other membrane
units.
(iv) A system that has been assigned a Bin 2, 3, or
4 classification under the provisions of subsection (c)(3)(B) of this
section must conduct direct integrity tests at least once each day
that the membrane unit is used for filtration. The executive director
may approve less frequent testing, based on demonstrated process reliability,
the use of multiple barriers effective for Cryptosporidium
removal or inactivation, or reliable process safeguards.
(v) A system must immediately conduct a direct integrity
test on any membrane unit that produces filtered water with turbidity
level above 0.15 NTU on two consecutive readings. The executive director
must establish alternate site-specific control limits for systems
that use other approved technology in lieu of turbidimeters to continuously
monitor the performance of membrane units.
(vi) A system must immediately remove any membrane
unit that fails a direct integrity test from service until the membrane
modules in that unit are inspected and, if necessary, repaired. A
membrane unit that has been removed from service may not be returned
to service until it has passed a direct integrity test.
(E) A system that uses cartridge filters must continuously
monitor the performance of the filtration process in a manner approved
by the executive director.
(3) Analytical requirements. All monitoring required
by this subsection must be conducted by a facility approved by the
executive director and using methods that conform to the requirements
of §290.119 of this title. Equipment used for compliance measurements
must be maintained and calibrated in accordance with §290.46(s)
of this title.
(A) Turbidity of the combined effluent must be measured
with turbidimeters that meet the requirements of subsection (e)(5)(A)
of this section.
(B) The turbidity of the water produced by each membrane
unit must be measured using the Hach FilterTrak Method 10133. The
executive director may approve the use of alternative technology to
monitor the quality of the water produced by each membrane unit.
(C) A system continuously monitoring the performance
of individual cartridges or membrane units may monitor combined effluent
turbidity levels by either continuously monitoring turbidity levels
with an on-line turbidimeter, or by measuring the turbidity level
in grab samples with a bench-top turbidimeter.
(D) Data collected from on-line instruments may be
recorded electronically by a SCADA system or on a strip chart recorder.
The recorder must be designed so that the operator can accurately
determine the value of readings at the monitoring interval approved
by the executive director.
(i) If there is a failure in the continuous monitoring
equipment at a system serving 10,000 people or more, the system must
conduct grab sampling every four hours in lieu of continuous monitoring,
but for no more than five working days following the failure of the
equipment.
(ii) If there is a failure in the continuous monitoring
equipment at a system serving fewer than 10,000 people, the system
must conduct grab sampling every four hours in lieu of continuous
monitoring, but for no more than 14 working days following the failure
of the equipment.
(E) A system that uses cartridge filters and does not
continuously monitor the turbidity of each filter unit must monitor
the performance of individual filters at least once each day using
a bench-top turbidimeter.
(F) Combined filter effluent and individual filter
effluent turbidity monitoring equipment and all associated data recording
devices shall read and record turbidity levels to adequately determine
compliance with the requirements as described in this subchapter.
The turbidity equipment and all associated recording devices shall
read and record levels:
(i) at least 10% higher than the turbidity level needed
to determine compliance with the highest applicable regulatory requirement
as described in this subchapter;
Cont'd... |
