| (a) Capacity and location.
(1) Based on current acceptable design standards, the
total capacity of the public water system's treatment facilities must
always be greater than its anticipated maximum daily demand. The water
treatment plant and all pumping units shall be located in well-drained
areas not subject to flooding and away from seepage areas or where
the groundwater water table is near the surface.
(A) Water treatment plants shall not be located within
500 feet of a sewage treatment plant or lands irrigated with sewage
effluent. A minimum distance of 150 feet must be maintained between
any septic tank drainfield line and any underground treatment or storage
unit. Any sanitary sewers located within 50 feet of any underground
treatment or storage unit shall be constructed of ductile iron or
polyvinyl chloride (PVC) pipe with a minimum pressure rating of 150
pounds per square inch (psi) and have watertight joints.
(B) Plant site selection shall also take into consideration
the need for disposition of all plant wastes in accordance with all
applicable regulations and state statutes, including both liquid and
solid wastes, or by-product material from operation and/or maintenance.
(3) Each water treatment plant shall be located at
a site that is accessible by an all-weather road.
(b) Groundwater.
(1) Disinfection facilities shall be provided for all
groundwater supplies for the purpose of microbiological control and
distribution protection and shall be in conformity with applicable
disinfection requirements in subsection (e) of this section and in
a manner consistent with the requirements of §290.110 of this
title (relating to Disinfectant Residuals).
(2) Treatment facilities shall be provided for groundwater
if the water does not meet the drinking water standards. The facilities
provided shall be in conformance with established and proven methods.
(A) Filters provided for turbidity and microbiological
quality control shall be preceded by coagulant addition and shall
conform to the requirements of subsection (d)(11) of this section.
Filtration rates for iron and manganese removal, regardless of the
media or type of filter, shall be based on a maximum rate of five
gallons per minute per square foot (gpm/sq ft).
(B) The removal of iron and manganese may not be required
if it can be demonstrated that these metals can be sequestered so
that the discoloration problems they cause do not exist in the distribution
system.
(C) All processes involving exposure of the water to
atmospheric contamination shall provide for subsequent disinfection
of the water ahead of ground storage tanks. Likewise, all exposure
of water to atmospheric contamination shall be accomplished in a manner
such that insects, birds, and other foreign materials will be excluded
from the water. Aerators and all other such openings shall be screened
with 16-mesh or finer corrosion-resistant screen.
(D) If reverse osmosis or nanofiltration membrane systems
are used, the design shall conform to the requirements in paragraph
(9) of this subsection.
(3) Any proposed change in the extent of water treatment
required will be determined on the basis of geological data, well
construction features, nearby sources of contamination, and on qualitative
and quantitative microbiological and chemical analyses.
(4) Appropriate laboratory facilities shall be provided
for controls as well as to check the effectiveness of disinfection
or any other treatment processes employed.
(5) All plant piping shall be constructed to minimize
leakage.
(6) All groundwater systems shall provide sampling
taps for raw water, treated water, and at a point representing water
entering the distribution system at every entry point.
(7) Air release devices shall be installed in such
a manner as to preclude the possibility of submergence or possible
entrance of contaminants. In this respect, all openings to the atmosphere
shall be covered with 16-mesh or finer corrosion-resistant screening
material or an equivalent acceptable to the executive director.
(8) The executive director may require 4-log removal
or inactivation of viruses based on raw water sampling results required
by §290.116 of this title (relating to Groundwater Corrective
Actions and Treatment Techniques).
(9) Reverse osmosis or nanofiltration membrane systems
used for the treatment of primary and secondary contaminants defined
in Subchapter F of this chapter (relating to Drinking Water Standards
Governing Drinking Water Quality and Reporting Requirements for Public
Water Systems), must meet the design criteria in subparagraphs (A)
- (L) of this paragraph.
(A) The design for all reverse osmosis and nanofiltration
membrane systems must be in accordance with the findings of the engineering
report. Variations from the engineering report must be explained and
shall not compromise public health. Minimum engineering report requirements
are found in §290.39(e)(1) and (6) of this title (relating to
General Provisions).
(B) The reverse osmosis and nanofiltration membrane
systems must be designed to ensure adequate cleaning of the membrane
system.
(C) The reverse osmosis or nanofiltration membrane
systems must be designed to operate at flux rates which assure effective
filtration at all times based on at least one of the following:
(i) manufacturer's computer models for new and end-of-life
membranes;
(ii) site-specific pilot study;
(iii) comparable design data from an alternative site;
or
(iv) the manufacturer's allowable operating parameters,
if the membrane unit's capacity is rated less than 300 gallons per
minute.
(D) Pretreatment shall be provided such that the feed
water quality to the membrane units shall meet the minimum allowable
requirements of the membrane manufacturer. Pretreatment processes
shall be sized correctly for the flow of the plant, and the components
and chemicals used for pretreatment in contact with the water must
conform to American National Standards Institute/NSF International
(ANSI/NSF) Standard 60 for Drinking Water Treatment Chemicals or ANSI/NSF
Standard 61 for Drinking Water System Components. Other pretreatment
processes will be reviewed on an individual basis in accordance with
the innovative/alternate treatment requirements specified in subsection
(g) of this section. Acceptable pretreatment techniques include:
(i) bags, cartridge filters, or screens for particulate
removal;
(ii) chemical addition that will not adversely affect
the reverse osmosis or nanofiltration membrane;
(iii) filters for iron and manganese removal in accordance
with paragraph (2)(A) of this subsection;
(iv) aeration or degasification; and
(v) ion exchange softening.
(E) The treatment plant must include post-treatment
facilities for corrosivity control, re-mineralization and the removal
of dissolved gases, such as carbon dioxide and hydrogen sulfide, if
necessary to meet the system's water quality goals. The treatment
must be sized correctly for the flow of the plant, and the components
and chemicals used for treatment must conform to ANSI/NSF Standard
60 for Drinking Water Treatment Chemicals or ANSI/NSF Standard 61
for Drinking Water System Components.
(F) Pipes and pipe galleries shall meet the minimum
requirements specified in subsection (d)(12) and (13) of this section.
(G) Each reverse osmosis or nanofiltration membrane
unit shall be equipped to measure conductivity or total dissolved
solids in the feed and the permeate water.
(H) Chemical storage and chemical feed facilities shall
comply with subsection (f) of this section.
(I) Provide cross-connection protection for common
piping used for cleaning and normal production modes.
(J) Provide flow meters on the pipes for feed, permeate,
and concentrate water. Additional metering devices shall be provided
as appropriate to monitor the flow rate through specific treatment
processes. Metering devices shall be located to facilitate use and
to assist in the determination of chemical dosages, the accumulation
of water production data, and the operation of plant facilities.
(K) The water system must provide pressure measuring
and recording devices before and after each membrane stage.
(L) The water system must provide equipment to monitor
the temperature of the water. 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) Groundwater under the direct influence of surface
water, springs, and other water sources.
Cont'd... |
