| (1) Water obtained from springs, infiltration galleries,
wells in fissured areas, wells in carbonate rock formations, or wells
that do not penetrate impermeable strata or any other source subject
to surface or near surface contamination of recent origin shall be
evaluated for the provision of treatment facilities. Groundwater under
the direct influence of surface water, as defined in §290.38
of this title (relating to Definitions), shall be provided minimum
treatment as required by the executive director under this subsection
or subsection (d) of this section, as applicable. Minimum treatment
shall consist of coagulation with direct filtration and adequate disinfection.
In all cases, the treatment process shall be designed to achieve at
least a 2-log removal of Cryptosporidium oocysts,
a 3-log removal or inactivation of Giardia cysts,
and a 4-log removal or inactivation of viruses before the water is
supplied to any consumer. The executive director may require additional
levels of treatment in cases of poor source water quality. Based on
raw water monitoring results, the executive director may require additional
levels of treatment for Cryptosporidium treatment
as specified in §290.111 of this title (relating to Surface Water
Treatment).
(A) Filters provided for turbidity and microbiological
quality control shall conform to the requirements of subsection (d)(11)
of this section.
(B) 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.
(2) 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 qualitative
and quantitative microbiological and chemical analyses.
(3) Appropriate laboratory facilities shall be provided
for controls as well as for checking the effectiveness of disinfection
or any other treatment processes employed.
(4) All plant piping shall be constructed to minimize
leakage. No cross-connection or interconnection shall be permitted
to exist between a conduit carrying potable water and another conduit
carrying raw water or water in a prior stage of treatment.
(5) All systems using springs and other water sources
shall provide sampling taps for raw water, treated water, and at a
point representing water entering the distribution system at every
entry point.
(6) Return of the decanted water or sludge to the treatment
process shall be adequately controlled so that there will be a minimum
of interference with the treatment process and shall conform to the
applicable requirements of subsection (d)(3) of this section. Systems
that do not comply with the provisions of subsection (d)(3) of this
section commit a treatment technique violation and must notify their
customers in accordance with the requirements of §290.122(b)
of this title (relating to Public Notification).
(7) Air release devices on treated waterlines 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) Reverse osmosis and nanofiltration membrane systems
not provided for microbiological quality control shall conform to
the requirements of subsection (b) of this section.
(d) Surface water.
(1) All water secured from surface sources shall be
given complete treatment at a plant which provides facilities for
pretreatment disinfection, taste and odor control, continuous coagulation,
sedimentation, filtration, covered clearwell storage, and terminal
disinfection of the water with chlorine or suitable chlorine compounds.
In all cases, the treatment process shall be designed to achieve at
least a 2-log removal of Cryptosporidium oocysts,
a 3-log removal or inactivation of Giardia cysts,
and a 4-log removal or inactivation of viruses before the water is
supplied to any consumer. The executive director may require additional
levels of treatment in cases of poor source water quality. Based on
raw water monitoring results, the executive director may require additional
levels of treatment for Cryptosporidium treatment
as specified in §290.111 of this title.
(2) All plant piping shall be constructed so as to
be thoroughly tight against leakage. No cross-connection or interconnection
shall be permitted to exist in a filtration plant between a conduit
carrying filtered or post-chlorinated water and another conduit carrying
raw water or water in any prior stage of treatment.
(A) Vacuum breakers must be provided on each hose bibb
within the plant facility.
(B) No conduit or basin containing raw water or any
water in a prior stage of treatment shall be located directly above,
or be permitted to have a single common partition wall with another
conduit or basin containing finished water.
(C) Make-up water supply lines to chemical feeder solution
mixing chambers shall be provided with an air gap or other acceptable
backflow prevention device.
(D) Filters shall be located so that common walls will
not exist between them and aerators, mixing and sedimentation basins
or clearwells. This rule is not strictly applicable, however, to partitions
open to view and readily accessible for inspection and repair.
(E) Filter-to-waste connections, if included, shall
be provided with an air gap connection to waste.
(F) Air release devices on treated waterlines 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.
(3) Return of the decanted water or solids to the treatment
process shall be adequately controlled so that there will be a minimum
of interference with the treatment process. Systems that do not comply
with the provisions of this paragraph commit a treatment technique
violation and must notify their customers in accordance with the requirements
of §290.122(b) of this title.
(A) Unless the executive director has approved an alternate
recycling location, spent backwash water and the liquids from sludge
settling lagoons, spent backwash water tanks, sludge thickeners, and
similar dewatering facilities shall be returned to the raw waterline
upstream of the raw water sample tap and coagulant feed point. The
blended recycled liquids shall pass through all of the major unit
processes at the plant.
(B) Recycle facilities shall be designed to minimize
the magnitude and impact of hydraulic surges that occur during the
recycling process.
(C) Solids produced by dewatering facilities such as
sludge lagoons, sludge thickeners, centrifuges, mechanical presses,
and similar devices shall not be returned to the treatment plant without
the prior approval of the executive director.
(4) Reservoirs for pretreatment or selective quality
control shall be provided where complete treatment facilities fail
to operate satisfactorily at times of maximum turbidities or other
abnormal raw water quality conditions exist. Recreational activities
at such reservoirs shall be prohibited.
(5) Flow-measuring devices shall be provided to measure
the raw water supplied to the plant, the recycled decant water, the
treated water used to backwash the filters, and the treated water
discharged from the plant. 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.
(6) Chemical storage facilities shall comply with applicable
requirements in subsection (f)(1) of this section.
(7) Chemical feed facilities shall comply with the
applicable requirements in subsection (f)(2) of this section.
(8) Flash mixing equipment shall be provided.
(A) Plants with a design capacity greater than 3.0
million gallons per day (MGD) must provide at least one hydraulic
mixing unit or at least two sets of mechanical flash mixing equipment
designed to operate in parallel. Public water systems with other surface
water treatment plants, interconnections with other systems, or wells
that can meet the system's average daily demand are exempt from the
requirement for redundant mechanical flash mixing equipment.
Cont'd... |
