| (B) The membrane system must be designed to conduct
and record the results of direct integrity testing in a manner that
demonstrates a removal efficiency equal to or greater than the removal
credit awarded to the membrane filtration system approved by the executive
director and meets the requirements in clauses (i) and (ii) of this
(i) The design must provide for direct integrity testing
of each membrane unit.
(ii) The design must provide direct integrity testing
that has a resolution of 3 micrometers or less.
(iii) The design must provide direct integrity testing
with sensitivity sufficient to verify the log removal credit approved
by the executive director. Sensitivity is determined by the criteria
in 40 CFR §141.719(b)(3)(iii).
(iv) The executive director may reduce the direct integrity
testing requirements for membrane units.
(C) The membrane system must be designed to conduct
and record continuous indirect integrity monitoring on each membrane
unit. 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.
(D) The level of removal credit approved by the executive
director shall not exceed the lower of:
(i) the removal efficiency demonstrated during challenge
testing conducted under the conditions in subparagraph (A) of this
(ii) the maximum removal efficiency that can be verified
through direct integrity testing used with the membrane filtration
process under the conditions in subparagraph (B) of this paragraph.
(E) Pilot studies must be conducted using membrane
modules that will meet the requirements of this section.
(F) Membrane systems must be designed so that membrane
units' feed water, filtrate, backwash supply, waste, and chemical
cleaning piping shall have cross-connection protection to prevent
chemicals from all chemical cleaning processes from contaminating
other membrane units in other modes of operation. This may be accomplished
by the installation of a double block and bleed valving arrangement,
a removable spool system, or other alternative methods approved by
the executive director.
(4) Bag, cartridge, or membrane filtration systems
or modules installed or replaced before April 1, 2012, and used for
microbiological treatment, can receive up to a 2.0-log removal credit
for Cryptosporidium and up to a 3.0-log
removal credit for Giardia based on
site-specific pilot study results, design, operation, and reporting
(5) Ultraviolet (UV) light reactors used for microbiological
inactivation can receive Cryptosporidium,
Giardia, and virus inactivation credit if the reactors meet
the criteria in subparagraphs (A) - (C) of this paragraph.
(A) UV light reactors can receive inactivation credit
only if they are located after filtration.
(B) In lieu of a pilot study, the UV light reactors
must undergo validation testing to determine the operating conditions
under which a UV reactor delivers the required UV dose. Validation
testing must be conducted according to the criteria established by
40 CFR §141.720(d)(2) and the executive director.
(i) The validation study must include the following
factors: UV absorbance of the water; lamp fouling and aging; measurement
uncertainty of on-line sensors; UV dose distributions arising from
the velocity profiles through the reactor; failure of UV lamps and
other critical system components; inlet and outlet piping or channel
configuration of the UV reactor; lamp and sensor locations; and other
parameters determined by the executive director.
(ii) Validation testing must be conducted on a full-scale
reactor that is essentially identical to the UV reactor(s) to be used
by the system and using waters that are essentially identical in quality
to the water to be treated by the UV reactor.
(C) The UV light reactor systems must be designed to
monitor and record parameters to verify the UV reactors operation
within the validated conditions approved by the executive director.
The UV light reactor must be equipped with facilities to monitor and
record UV intensity as measured by a UV sensor, flow rate, lamp status,
and other parameters designated by the executive director.
(6) Membrane filtration used by groundwater systems
to achieve at least 4-log removal of viruses to comply with the groundwater
rule requirements under §290.109 of this title (relating to Microbial
Contaminants) and §290.116 of this title, the public water system
shall meet the following criteria.
(A) The membrane module must have an absolute molecular
weight cut-off, or an alternate parameter that describes the exclusion
characteristics of the membrane, that can reliably achieve at least
4-log removal of viruses.
(B) The membrane system must be designed to conduct
and record the results of integrity testing in a manner that demonstrates
a removal efficiency equal to or greater than the removal credit awarded
to the membrane system approved by the executive director.
(h) Sanitary facilities for water works installations.
Toilet and hand washing facilities provided in accordance with established
standards of good public health engineering practices shall be available
at all installations requiring frequent visits by operating personnel.
(i) Permits for waste discharges. Any discharge of
wastewater and other plant wastes shall be in accordance with all
applicable state and federal statutes and regulations. Permits for
discharging wastes from water treatment processes shall be obtained
from the commission, if necessary.
(j) Treatment chemicals and media. All chemicals and
any additional or replacement process media used in treatment of water
supplied by public water systems must conform to ANSI/NSF Standard
60 for Drinking Water Treatment Chemicals and ANSI/NSF Standard 61
for Drinking Water System Components. Conformance with these standards
must be obtained by certification of the product by an organization
accredited by ANSI.
(1) Safety equipment for all chemicals used in water
treatment shall meet applicable standards established by the OSHA
or Texas Hazard Communication Act, Texas Health and Safety Code, Chapter
(2) Systems must comply with United States Environmental
Protection Agency (EPA) requirements for Risk Management Plans.
(l) Plant operations manual. A thorough plant operations
manual must be compiled and kept up-to-date for operator review and
reference. This manual should be of sufficient detail to provide the
operator with routine maintenance and repair procedures, with protocols
to be utilized in the event of a natural or man-made catastrophe,
as well as provide telephone numbers of water system personnel, system
officials, and local/state/federal agencies to be contacted in the
event of an emergency. If operating a reverse osmosis or nanofiltration
membrane system, the manual must also include the system's configuration,
baseline performance data, and any set point for membrane cleaning
(m) Security. Each water treatment plant and all appurtenances
thereof shall be enclosed by an intruder-resistant fence. The gates
shall be locked during periods of darkness and when the plant is unattended.
A locked building in the fence line may satisfy this requirement or
serve as a gate.
(n) Corrosion control treatment. Systems must install
any corrosion control or source water treatment required by §290.117(f)
and (g) of this title (relating to Regulation of Lead and Copper),
respectively. Such treatment must be designed and installed consistent
with the requirements of this subchapter. The requirements of 40 CFR §141.82(i)
and §141.83(b)(7) relating to EPA involvement in treatment determination
are adopted by reference.
|Source Note: The provisions of this §290.42 adopted to be effective September 13, 2000, 25 TexReg 8880; amended to be effective May 16, 2002, 27 TexReg 4127; amended to be effective February 19, 2004, 29 TexReg 1373; amended to be effective January 9, 2008, 33 TexReg 198; amended to be effective May 15, 2011, 36 TexReg 2860; amended to be effective September 12, 2013, 38 TexReg 5880; amended to be effective July 30, 2015, 40 TexReg 4769; amended to be effective March 30, 2017, 42 TexReg 1466