Current through September 21, 2024
(a) 2018 TSS, parts
4.2.1, 4.2.1(b)-(c), clarification, presedimentation; 4.2.2-4.2.2(c),
clarification, coagulation; 4.2.4, 4.2.4(b)-4.2.4(d)(3), coagulation,
sedimentation; 4.3.1.1, filtration, rapid rate gravity filters, pretreatment;
4.3.1.4-4.3.1.4(o), filtration, rapid rate gravity filters, structural details
and hydraulics; 4.3.1.6-4.3.1.6(d)(2)(d), filtration, rapid rate gravity
filters, filter material; 4.3.1.6(d)(4), filtration, rapid rate gravity
filters, filter material, granular activated carbon (GAC);
4.3.1.6(e)-4.3.1.6(e)(1)(b), filtration, rapid rate gravity filters, filter
material, support media; 4.3.3.6-4.3.3.6(b), filtration, diatomaceous earth
filtration, pre-coat; 4.3.3.7-4.3.3.7(c), filtration, diatomaceous earth
filtration, body feed; 4.3.3.8-4.3.3.8(e), filtration, diatomaceous earth
filtration, filtration; 4.3.3.10- 4.3.3.10(a)(4), filtration, diatomaceous
earth filtration, appurtenances; 4.3.4.2, filtration, slow sand filters,
number; 4.3.4.4, filtration, slow sand filters, rates of filtration; 4.3.4.5,
filtration, slow sand filters, underdrains; 4.3.4.6-4.3.4.6(e), filtration,
slow sand filters, filter material; 4.3.4.7, filtration, slow sand filters,
filter gravel; 4.3.4.8, filtration, slow sand filters, depth of water on filter
beds; 4.3.4.9, 4.3.4.9(b), (e) and (f), filtration, slow sand filters, control
appurtenances; 4.4.1- 4.4.1(b), disinfection, contact time, CT, and point(s) of
application; 4.4.3- 4.4.3(d) and (f), disinfection, testing equipment; 4.4.4.3,
disinfection, chlorine, automatic switch-over; 4.4.4.7, disinfection, chlorine,
cross-connection protection; 4.4.4.8, disinfection, chlorine, pipe material;
4.4.5, disinfection, chloramines; 4.4.6.1, disinfection, ozone, design
considerations; 4.4.6.2- 4.4.6.2(e), disinfection, ozone, feed gas preparation;
4.4.6.3- 4.4.6.3(d), disinfection, ozone, ozone generator; 4.4.6.4-4.4.6.4(b),
disinfection, ozone, ozone contactors; 4.4.6.5-4.4.6.5(g), disinfection, ozone,
ozone destruction unit; 4.4.6.6, disinfection, ozone, piping materials;
4.4.6.7-4.4.6.7(c), disinfection, ozone, joints and connections;
4.4.6.8-4.4.6.8(h), disinfection, ozone, instrumentation; 4.4.6.9-4.4.6.9(h),
disinfection, ozone, alarms; 4.4.6.11-4.4.6.11(c), disinfection, ozone,
construction considerations; 4.5.1, softening, lime or lime-soda process;
4.5.1.1, softening, lime or lime-soda process, hydraulics; 4.5.1.3, softening,
lime or lime-soda process, chemical feed point; 4.5.1.4, softening, lime or
lime-soda process, rapid mix; 4.5.1.5, softening, lime or lime-soda process,
stabilization; 4.5.1.6-4.5.1.6(b), softening, lime or lime-soda process, sludge
collection; 4.5.1.7, softening, lime or lime-soda process, sludge disposal;
4.5.1.8, softening, lime or lime-soda process, disinfection; 4.5.1.9,
softening, lime or lime-soda process, plant start-up; 4.5.2.1, softening,
cation exchange process, pre-treatment requirements; 4.5.2.2, softening, cation
exchange process, design; 4.5.2.3, softening, cation exchange process, design;
4.5.2.4, softening, cation exchange process, depth of resin; 4.5.2.5,
softening, cation exchange process, flow rates; 4.5.2.7, softening, cation
exchange process, underdrains and supporting gravel; 4.5.2.8, softening, cation
exchange process, brine distribution; 4.5.2.9, softening, cation exchange
process, cross-connection control; 4.5.2.10, softening, cation exchange
process, bypass piping and equipment; 4.5.2.11, softening, cation exchange
process, additional limitations; 4.5.2.12, softening, cation exchange process,
sampling taps; 4.5.2.13-4.5.2.13(f), softening, cation exchange process, brine
and salt storage tanks; 4.5.2.14, softening, cation exchange process, salt and
brine storage capacity; 4.5.2.15, softening, cation exchange process, brine
pump or eductor; 4.5.2.18, softening, cation exchange process, construction
materials; 4.5.2.19, softening, cation exchange process, housing; 4.5.3,
softening, water quality test equipment; 4.6-4.6.14, anion exchange treatment;
4.7-4.7.11, aeration; 4.8, iron and manganese control; 4.8.1-4.8.1.3, iron and
manganese control, removal by oxidation, detention and filtration; 4.8.2, iron
and manganese control, removal by the lime-soda softening process;
4.8.3-4.8.3(f), iron and manganese control, removal by manganese coated media
filtration;-4.8.4, iron and manganese control, removal by ion exchange;
4.8.6-4.8.6(d), iron and manganese control, sequestration by polyphosphates;
4.8.7-4.8.7(e), iron and manganese control, sequestration by sodium silicates;
4.8.8, iron and manganese control, sampling taps; 4.9.3-4.9.3(e), stabilization
and corrosion control, carbon dioxide addition; 4.9.5, 4.9.5(c)-4.9.5(c)(9),
stabilization and corrosion control, phosphates, design; 4.9.6-4.9.6.1(c)(4),
stabilization and corrosion control, pH/alkalinity adjustment; 4.10, taste and
odor control; 4.10.1, taste and odor control, flexibility; 4.10.2, taste and
odor control, chlorination; 4.10.3, taste and odor control, chlorine dioxide;
4.10.4-4.10.4(f), taste and odor control, powdered activated carbon; 4.10.8,
taste and odor control, potassium permanganate; 4.11, membrane technologies for
public water supplies; 4.11.1-4.11.1(c), membrane technologies for public water
supplies, pilot study/preliminary investigations; 4.11.2-4.11.2(l)(4), membrane
technologies for public water supplies, general design considerations;
4.11.3-4.11.3(h), membrane technologies for public water supplies, systems
treating surface water or GWUDI; 5.4.7-5.4.7(f), specific chemicals, fluoride;
5.4.8, specific chemicals, activated carbon; 9.3-9.3(a)(2), precipitative
softening sludge, lagoons; 9.4.1-9.4.1(h), alum sludge, lagoons; 9.5-9.5.1(k),
red water waste, sand filters; 9.5.2-9.5.2(g), red water waste, lagoons; 9.5.3,
red water waste, discharge to community sanitary sewer; are herein incorporated
by reference.
(b) The capacity of
the water treatment or water production system shall be designed for the
maximum daily demand at the design year.
(c) Presedimentation shall be required for
raw waters that have episodes of turbidity in excess of 1,000 Nephelometric
turbidity units (NTU) for a period of one week or longer.
(d) Basins shall meet the following
requirements:
(i) Basins without mechanical
sludge collection equipment shall have a minimum detention time of three
days;
(ii) Basins with mechanical
sludge collection equipment shall have a minimum detention time of three
hours;
(iii) Basins shall have a
bottom slope to drain of 1/4 inch per foot without mechanical sludge collection
equipment and two inches per foot with mechanical sludge collection equipment;
and
(iv) Basins shall have a
minimum of one, eight-inch drain line to completely dewater the
facility.
(e) Rapid
dispersal of chemicals throughout the water shall be accomplished by mechanical
mixers, jet mixers, static mixers, or hydraulic jump and shall meet the
following requirements:
(i) For mechanical
mixers, the minimum Gt (velocity gradient (sec-1) x t (sec)) provided at
maximum daily flow shall be 27,000;
(ii) The detention time in a flash mixing
chamber shall not exceed 30 seconds at maximum daily flow conditions;
and
(iii) The basin shall have a
drain.
(f) Flocculation
shall comply with the following requirements:
(i) Mechanical flocculators shall be used for
low-velocity agitation of chemically treated water.
(ii) The minimum detention time of 10 minutes
shall be provided.
(iii) Basins
shall have a minimum of one drain line to dewater the facility.
(iv) The velocity gradient (G value) shall be
adjustable through the use of variable speed drives. The velocity gradient for
single basin systems shall be 30 sec-1, 20 sec-1 in the final basin of a
two-stage system, and 10 sec-1 in the final basin of a three-stage
system.
(v) The tip speed for a
single-speed drive system shall not exceed 3 feet per second (ft/sec). Variable
speed drives shall provide tip speeds between 0.5 and 3.0 ft/sec.
(vi) The velocity of flocculated water
through pipes or conduits to settling basins shall not be less than 0.5 ft/sec
or greater than 1.5 ft/sec.
(g) Sedimentation basins shall comply with
the following requirements:
(i) The maximum
diameter in circular basins shall be 80 feet.
(ii) The minimum basin side water depth shall
be eight feet if mechanical sludge collection equipment is provided or basin
sludge hopper segments are less than 100 square feet in surface area and 15
feet if basins are manually cleaned.
(iii) The outer walls of the settling basin
shall extend at least 12 inches above the surrounding ground and provide at
least 12 inches of freeboard to the water surface. Where the basin walls are
less than four feet above the surrounding ground, a fence or other debris
barrier shall be provided on the wall.
(iv) Basin bottoms shall slope toward the
drain at not less than one inch per foot where mechanical sludge collection
equipment is provided and 1/4 inch per foot where no mechanical sludge
collection equipment is provided.
(v) The basin overflow rate shall not exceed
1,000 gpd/ft2 at design conditions.
(vi) Mechanical sludge collection shall be
provided if settleable organics are present in the water or the source water
exceeds secondary maximum contaminant levels identified at
40 CFR
143.3.
(vii) Pipes for removing sludge shall not be
less than six inches in diameter and arranged to facilitate cleaning. Valves on
sludge lines shall be located outside the tank.
(h) Facilities with softening sedimentation
or clarification for softened groundwater sources shall meet the following
requirements:
(i) The basin overflow rate
shall not exceed 21,000 gpd/ft2 at the design flow;
and
(ii) Mechanical sludge removal
shall be provided and shall be designed to handle a load of 40 lbs/ft of
collector scraper arm length.
(i) Solids contact units are acceptable for
combined softening and clarification of well water where water quality
characteristics are not variable and flow rates are uniform and consistent.
Solids contact units shall meet the requirements of paragraphs (c) and (e) of
this Section and may be considered under the following circumstances:
(i) Solids contact units may be considered
for use as clarifiers without softening when they are designed as conventional
sedimentation units; and
(ii)
Solids contact units may be used for other treatment processes such as rapid
mixing or flocculation when the individual components of the units are designed
for that specific treatment process.
(j) Tube clarifiers that are horizontal or
steeply inclined may be used when designed as follows:
(i) The maximum flow rate shall be less than
2.0 gpm/ft2 based on the surface area of the basin
covered by the tubes;
(ii) The top
of the tubes shall be more than 12 inches from the underside of the launder and
more than 18 inches from the water surface and the spacing of the effluent
launder shall not be more than three times the distance from the water surface
to the top of the tube modules;
(iii) Sludge shall be removed using 45-degree
or steeper hoppered bottoms, mechanical devices that move the sludge to
hoppers, or devices that remove settled sludge from the basin floor using
differential hydraulic level; and
(iv) A method of tube cleaning shall be
provided that may include provisions for a rapid reduction in clarifier water
surface elevation, a water jet spray system, or an air scour system. If
cleaning is automatic, controls shall cease clarifier operation during tube
cleaning and a 20-minute rest period.
(k) Filtration systems shall comply with the
following requirements:
(i) Vertical or
horizontal pressure filters shall not be used on surface waters. Pressure
filters may be used for groundwater filtration, including iron and manganese
removal;
(A) Slow rate sand filters may be
used when maximum turbidity is less than 50 NTU and the turbidity present is
not caused by colloidal clay; and
(B) Maximum color shall not exceed 30
units.
(ii) Washwater
troughs shall comply with the following requirements:
(A) Washwater troughs shall not cover more
than 25 percent of the filter area;
(B) The minimum distance between the bottom
of the trough and the top of the unexpanded media shall be 12 inches;
(C) The minimum distance between the weir of
the trough and the unexpanded media shall be 30 inches;
(D) There shall be no more than six feet
clear distance between troughs;
(E)
The trough and wastewater line shall be sized for a filter backwash rate of 20
gpm/ft2 plus a surface wash rate of 2
gpm/ft2;
(F) The backwash system shall be sized to
provide a minimum backwash flowrate of 20 gpm/ft2 or
a rate necessary to provide a 50 percent expansion of the filter bed;
(G) The system and wash water storage shall
be designed to provide two, 20-minute washes in rapid succession and shall meet
the following requirements:
(I) If only one
filter is provided, the backwash system needs to provide only one 20-minute
backwash; and
(II) If pumps are
used to convey water to the filter(s) or to the wash water tank, two equivalent
pumps shall be provided.
(H) Washwater shall be filtered and
disinfected;
(I) The washwater rate
shall be controlled on the main wash water line and the flowrates shall be
metered and indicated;
(J)
Air-assisted backwash systems may be used when the design precludes disturbing
the gravel support and the minimum flowrate for air-assisted backwash shall be
12 gpm/ft2;
(K) A surface wash system shall be provided
and shall meet the following requirements:
(I)
The system shall be capable of supplying 0.5 gpm/ft2
for a system with rotating arms and 2 gpm/ft2 for
fixed nozzles, at a minimum pressure of 50 psi; and
(II) The surface wash can be
air-assisted.
(L) Both
backwash and surface wash supply systems shall be provided with adequate
backflow prevention;
(iii)
Single media beds shall use either clean crushed anthracite or a sand and
anthracite mixture, the media shall have an effective size of 0.45 - 0.55 mm
and a uniformity coefficient not greater than 1.65, and shall meet the
following requirements:
(A) When gravel is
used as supporting media, it shall consist of coarse aggregate in which most of
it is round and of similar size and shape;
(B) Gravel as supporting media shall have
sufficient strength and hardness to resist degradation during handling and use,
be free of harmful materials and exceed the minimum density requirements;
and
(C) The gravel shall also
comply with AWWA B100 specifications.
(iv) Dual media coal sand filters shall
consist of a coarse layer of coal not less than 15 inches deep above a layer of
fine sand not less than eight inches deep on a torpedo sand or garnet layer of
support not less than three inches on gravel support.
(v) Filter bottoms and strainer systems shall
be limited to pipe, perforated pipe laterals, tile block, and perforated tile
block. Perforated plate bottoms or plastic nozzles shall not be used.
(vi) Every filter shall have:
(A) Influent and effluent taps;
(B) A head loss gauge;
(C) An indicating effluent
turbidimeter;
(D) A waste drain for
draining the filter component to waste;
(E) A filter rate flow meter;
(F) Polymer feed facilities including polymer
mixing, storage tank and at least one feed pump for each filter compartment;
and
(G) Recorders on the
turbidimeters.
(vii)
Filter rate control shall be such that the filter is not surged. The filter
rate of flow shall not change more than 0.3gpm/ft2
per minute. A filter that stops and restarts during a cycle shall have a
filter-to-waste system installed. Declining flow rate filters shall not be used
unless the flow rate for each filter is controlled to a rate less than allowed
in paragraph (j)(iii) of this Section and there are four more individual
filters.
(viii) A filter to waste
cycle shall be provided after the filter backwash operation. The filter to
waste cycle shall be at least 10 minutes.
(ix) Multi-media filter beds shall contain a
depth of fine media made up of anthracite (specific gravity 1.5), silica sand
(specific gravity 2.6), and garnet sand or ilmenite (specific gravity 4.2-4.5).
The bed depths and distribution shall be determined by the water quality and
shall meet the following requirements:
(A)
There shall not be less than 10 inches of fine sand and 24 inches of
anthracite;
(B) The relative size
of the media shall be such that the hydraulic grading of the material during
backwash will result in a pore space that progressively goes from coarse to
fine in the direction of flow;
(C)
The multi-media shall be supported on two layers of special high-density gravel
placed above the conventional silica gravel supporting bed;
(D) The special gravel shall have a specific
gravity not less than 4.2;
(E) The
bottom layer shall consist of particles passing U.S. Standard 5 mesh sieves and
retained in U.S. Standard 12 mesh sieves and shall be 1 1/2 inches thick;
and
(F) The top layer shall consist
of particles passing U.S. Standard 12 mesh sieves and retained in U.S. Standard
20 mesh sieves and shall be 1 1/2 inches thick.
(x) Diatomaceous earth filtration shall
comply with the following requirements:
(A)
Diatomaceous earth filters may be used under the following circumstances:
(I) To remove turbidity from surface waters
where turbidities entering the filters do not exceed 10 NTU and where total raw
water coliforms do not exceed 100 organisms/100 mL;
(II) Where the raw water quality exceeds the
previously mentioned limits when flocculation and sedimentation are used
preceding the filters; and
(III) To
remove iron from groundwaters.
(B) The proposed diatomaceous earth
filtration shall include pressure or vacuum type units; and
(C) A precoating system shall be
provided.
(D) The proposed
diatomaceous earth filtration shall include a continuous monitoring
turbidimeter with recorder on each filter effluent for plants treating surface
water.
(l) All
designs that propose supplies of surface water, groundwater under the direct
influence of surface water, and groundwater that does not meet 40 CFR Part 141
or where other treatment is provided, shall include disinfection via one of the
following methods:
(i) Chlorine;
(ii) Chloramines, recommended only for
secondary disinfection;
(iii)
Chlorine dioxide;
(iv)
Ozone;
(v) Ultraviolet light;
or
(vi) Other disinfecting agents
that demonstrate reliable application equipment is available and that include
testing procedures for a residual that is recognized in Standard Methods for
the Examination of Water and Wastewater 2018.
(m) All designs that require disinfection
shall demonstrate that:
(i) The system will
maintain a detectable residual throughout the distribution system;
and
(ii) The applicant has
considered the formation of disinfection byproducts when selecting the
disinfection.
(n)
Disinfection equipment shall comply with the following requirements:
(i) Chlorination equipment shall comply with
NSF/ANSI/CAN 61-2020/NSF/ANSI/CAN 600-2021 and the following requirements:
(A) Positive displacement pumps shall be
provided for solution feed gas chlorinators or hypochlorite feeders;
(B) The chlorine solution injector/diffuser
shall provide a rapid and thorough mix with all the water being
treated;
(C) If the application
point is to a pipeline discharging to a clearwell, the chlorine shall be added
to the center of the pipe at least 10 pipe diameters upstream of the discharge
into the clearwell;
(D) Gas
chlorinators shall comply with the following requirements:
(I) The injector/eductor shall be selected
based on solution pressure, injector water flowrate, feed point backpressure,
and chlorine solution line length and size;
(II) The maximum feed point backpressure
shall not exceed 110 psi unless a chlorine solution pump is used; and
(III) Gauges shall be provided for chlorine
solution pressure, feed water pressure, and chlorine gas pressure or
vacuum.
(E) Standby
equipment of sufficient capacity shall be available to replace the largest
chlorinator unit. Well systems providing no treatment other than disinfection
are exempt from the requirements of this paragraph (E) and are not required to
provide standby chlorination equipment.
(ii) Points of application and contact time
shall comply with the following requirements:
(A) Filtration types shall comply with the
contact time and minimum chlorine residuals required in Table 3 of this Section
after the appropriate baffling factor has been applied to the reactor. Contact
times assume a baffling factor of 0.1 unless documentation justifying the use
of a higher baffling factor is provided. Contact time requirements are based on
worst-case operating conditions of water temperature of 32.9 degrees Fahrenheit
and pH of 9.
Table 3. Required Contact Time and Residual by
Filtration Type
|
Filtration Type
|
Required Contact Time (minutes),
0.4 mg/L minimum chlorine residual
|
Required Contact Time (minutes),
1.0 mg/L minimum chlorine residual
|
|
Conventional Filtration |
162.5
|
73 |
|
Direct Filtration, Bag or Cartridge Filtration, Slow
Sand Filtration, Diatomaceous Earth Filtration
|
325 |
146
|
|
Membrane Filtration (MF or UF) |
30
|
12 |
(B)
When chlorine is applied to a groundwater source to maintain a residual, a
4-log inactivation shall be achieved prior to the first customer.
(o) Systems that propose
disinfection via ultraviolet light shall comply with the following
requirements:
(i) Proposed designs for
ultraviolet light shall include the following information in the ultraviolet
reactor influent water quality analysis:
(A)
Influent temperature (degrees Fahrenheit);
(B) UV transmittance (UVT) at a reported
wavelength of 254 nm and a pathlength of 1 cm;
(C) A description of the UVT range over a
12-month period;
(D) Total hardness
(mg/L as CaCO3);
(E) pH;
(F) Alkalinity (mg/L as
CaCO3);
(G)
Total iron (mg/L) influent < 0.3mg/L;
(H) Calcium (mg/L); and
(I) Total manganese (mg/L) influent <0.03
mg/L
(ii) Proposed
designs for ultraviolet disinfection systems shall include the following
information:
(A) The maximum, average, and
minimum flowrates;
(B) A matrix
that identifies paired flow and ultraviolet treatment values;
(C) A description of the organisms targeted
for inactivation;
(D) Log
inactivation requirements;
(E)
Operating approach (UV intensity vs. calculated dose);
(F) Maximum and minimum operating
pressures;
(G) Maximum pressure at
the UV reactor;
(H) UV system
redundancy;
(I) Lamp cleaning
strategy;
(J) Mercury trap for
broken UV lamps;
(K) Maximum
headloss through the UV reactor;
(L) A demonstration that the UV reactor(s)
shall be hydrostatically tested to 1.5 times the rated operating
pressure;
(M) A demonstration that
the UV reactor(s) shall be designed to ensure that plant personnel can change
lamps and the UV intensity meter without draining the reactor; and
(N) A demonstration that the units shall meet
NSF/ANSI/CAN Standard 61.
(iii) Ultraviolet treatment systems shall be
designed to comply with the Ultraviolet Disinfection Guidance Manual for the
Final LT2ESWTR and the following dose requirements:
(A) The UV disinfection system shall deliver
a validated dose that meets or exceeds the required dose at the end of lamp
life, with fouled sleeves.
(B) The
minimum required validated dose used for system design shall incorporate a
Combined Age and Fouling Factor (CAF), calculated as:
CAF = EOLL x FF.
EOLL is the ratio of the lamp output at the end of life
relative to the new lamp output
FF is the fouling factor.
(C) The EOLL shall be 75 percent of the new
lamp output.
(D) The FF shall be:
(I) 0.5 for UV systems with no sleeve wiping
system;
(II) 0.75 for UV systems
with mechanical wiping only; or
(III) 0.95 for UV systems with a combined
online chemical and mechanical cleaning.
(E) The validated dose that meets or exceeds
the required dose shall be delivered under maximum flow and design (UVT)
condition, when the larger UV unit is out of service.
(iv) Ultraviolet disinfection shall comply
with the following validation requirements:
(A) The applicant shall submit the
manufacturer's bioassay validation report for the proposed UV reactor with the
permit application;
(B) The
bioassay testing and results shall demonstrate validation by an independent
third party in full compliance with the Ultraviolet Disinfection Guidance
Manual for the Final LT2ESWTR;
(C)
The owner and engineer shall submit a certification to the Administrator if
validation requirements are adjusted and identify each of the equipment and
system modifications required to ensure that the appropriate dosage is provided
for the inactivation requirements;
(D) Bioassay testing shall evaluate reactor
performance over the range of:
(I) Flowrates
(maximum, average, and minimum);
(II) UVT from 70 percent to 98 percent
(measured at 254 nm, 1 cm path length); and
(III) RED at maximum flowrate and design UVT
conditions.
(E) The
bioassay testing shall incorporate the range of design and operating conditions
described in paragraph (o)(i) of this Section for UV Light;
(F) Extrapolations to flowrates, UV
transmittance values, or UV doses outside the range actually tested, are not
permitted; and
(G) Bioassay testing
shall also verify that the head loss generated by the proposed reactor is less
than or equal to the specified limits.
(v) Ultraviolet disinfection hydraulics shall
comply with the following requirements:
(A)
The inlet and outlet piping configuration to the UV reactor shall result in a
UV dose delivery that is equal to or greater than the dose delivered when the
UV reactor was validated;
(B) If
the UV reactor validation is performed off-site, the applicant shall refer to
the validation report to determine the validated inlet and outlet conditions
that apply to the site-specific requirements; and
(C) Ultraviolet hydraulic piping shall comply
with at least one of the following requirements:
(I) The piping configuration shall consist of
a minimum of 10 pipe diameters of straight pipe upstream and five pipe
diameters of straight pipe downstream of the UV reactors, with additional pipe
diameters above the minimum if required by the manufacturer's guidelines for
electromagnetic or other flowmeter installation;
(II) The inlet and outlet piping
configurations shall be identical to those constructed for the UV reactor
validation; or
(III) If on-site
validation or custom off-site validation is planned, the inlet and outlet
piping hydraulics must be designed according to the manufacturer's
recommendations and to accommodate any site-specific constraints.
(vi) Ultraviolet control
and measurement instrumentation for each reactor shall comply with the
following requirements:
(A) Each reactor shall
be capable of measuring UV intensity and lamp status (on/off);
(B) For systems that use the calculated dose
monitoring strategy, each reactor shall be capable of measuring or calculating
the UV transmittance;
(C) Piping
for each UV reactor shall be sized and configured in accordance with the
validated operating conditions and maintain equal head loss through each
reactor over the range of validated flowrates. Each UV reactor shall not be
by-passed;
(D) Each UV reactor
train shall have a dedicated flow meter to confirm the validated operating
conditions;
(E) UV lamps in the UV
reactor shall be submerged at all times during operation;
(F) The specific configuration of the UV
reactor(s) within a facility will dictate the use of air release, air/vacuum,
or combination air valves to prevent air pockets and negative pressure
conditions and the design shall verify that the UV manufacturer was consulted
to determine any equipment-specific air release and pressure control valve
requirements;
(G) Each UV reactor
shall have the piping configured so that it can be isolated and removed from
service while the other UV reactor(s) remain in service; and
(H) A booster pump shall be used if the head
loss constraints indicate that a pump is necessary. The UV reactor shall be
sized accordingly.
(vii)
The applicant shall describe the dose monitoring strategy and the operational
approach for the UV reactor that complies with the approaches described in
Ultraviolet Disinfection Guidance Manual for the Final LT2ESWTR, part
3.5.2.
(viii) The cleaning system
for each UV reactor shall comply with the following requirements:
(A) Each UV reactor shall be equipped with an
automatic online mechanical lamp sleeve cleaning system and may include
optional chemical cleaning;
(B) The
UV sensor shall include mechanical cleaning capabilities with an automatically
initiated and controlled cleaning cycle; and
(C) The UV reactor(s) shall be fully
operational and shall provide validated dose requirements during system
cleaning.
(ix) The
minimum spare parts kept at a facility shall include the following:
(A) 20 percent of the UV Lamps;
(B) Five percent of the lamp sleeves;
and
(C) One UV intensity
sensor.
(p)
Facilities that propose disinfection via fluoridation and defluoridation shall
comply with the following requirements:
(i)
Fluoride storage designs shall demonstrate that:
(A) Fluoride storage tanks shall be
covered;
(B) All other storage
shall be inside a building; and
(C)
Storage tanks of hydrofluorosilicic acid shall be vented to the atmosphere at a
point outside the building.
(ii) Fluoride feed equipment shall meet the
following requirements:
(A) There shall be
scales or weight loss recorders for dry chemical feeds and the feeders shall be
accurate to within five percent of any desired feed rate;
(B) The application of hydrofluorosilicic
acid, if into a horizontal pipe, shall be in the lower half of the
pipe;
(C) Fluoride compounds shall
not be added before lime soda or ion exchange softening;
(D) A fluoride solution shall be applied by a
positive displacement pump;
(E) The
solution shall not be injected into a point of negative pressure;
(F) All fluoride feed lines and dilution
water lines shall be isolated from the potable water supplies by either an air
gap above the solution tank or a reduced pressure principal backflow
preventer;
(G) Water used for
sodium fluoride solution shall have a hardness not exceeding 45 mg/L;
and
(H) Flow meters for treated
water flow and fluoride solution water shall be provided.
(iii) Provisions shall be made to allow the
transfer of dry fluoride compounds from shipping containers to storage bins or
hoppers that minimize the quantity of fluoride dust that enters the room where
the equipment is installed and shall meet the following requirements:
(A) The transfer system shall be equipped
with an exhaust fan and dust filter that places the hopper or storage bin under
negative pressure;
(B) Air
exhausted from fluoride handling equipment shall discharge through a dust
filter to the atmosphere outside the building and shall not discharge within 50
feet of a fresh air intake for the building; and
(C) A floor drain shall be provided for
cleaning equipment and maintenance.
(iv) The following methods are acceptable for
fluoride removal:
(A) Activated alumina may be
used in open gravity filters or pressure filter tanks;
(B) The minimum media depth shall be five
feet;
(C) The loading rate shall
not exceed 4 gpm/ft2;
(D) The mesh size for the alumina media shall
be between #28 and #48;
(E) Media
regeneration facilities shall be provided and shall include both weak caustic
and weak acid systems; and
(F) Bone
char filtration or lime softening with magnesium addition may be
used.
(v) Water that is
unstable due either to natural causes or to subsequent treatment shall be
stabilized.
(vi) Facilities shall
have the capability of feeding both acid and alkalinity.
(vii) Unstable water created by ion exchange
softening shall be stabilized by an alkali feed.
(viii) Laboratory equipment shall be provided
to determine the effectiveness of stabilization treatment. This shall include
testing equipment for hardness, calcium, alkalinity, pH, and magnesium at a
minimum.
(q) Taste and
odor control equipment shall comply with the following requirements:
(i) Open or closed, granular activated carbon
adsorption units may be used to absorb organics for taste and odor control,
subject to the following requirements:
(A) The
loading rate shall not exceed 10 gpm/ft2;
(B) The minimum empty bed contact time shall
be 20 minutes;
(C) The pH of the
water shall be less than 9.0 with a turbidity of less than 2 NTU when using
packed beds;
(D) There shall be
provisions for moving the carbon to and from the contactors;
(E) Contactors may be upflow or downflow
design. A single unit is acceptable for countercurrent upflow designs. Downflow
designs shall have two or more parallel units;
(F) Contactors shall be designed as open
gravity or pressure bed;
(G)
Pressure contactors shall have an air-vacuum relief valve fitted with a
stainless-steel screen to prevent plugging;
(H) The contactor materials of construction
shall be concrete, steel, or fiberglass-reinforced plastic and shall meet the
following requirements:
(I) Steel vessels
shall be protected against corrosion; and
(II) Inlet and outlet screens shall be made
of stainless steel or other suitable materials.
(I) There shall be provisions for flow
reversal and bed expansion that meet the following requirements:
(I) Backwashing facilities shall provide up
to 50 percent bed expansion; and
(II) Backwashing facilities shall meet the
backwash criteria as rapid filters.
(ii) If ozone is used for taste and odor
control, there shall be at least 10 minutes of contact time to complete all
reactions and the minimum applied feed rate of ozone shall be 1 mg/L, or the
design shall identify a contact time and feed rate that demonstrate the
application of ozone will not cause an exceedance of the maximum contaminant
levels identified at 40 CFR
141.64.
(r) Designs that include the addition of
phosphates for stabilization and corrosion control shall demonstrate the
evaluation of reactions with aluminum and impacts on wastewater treatment
plants to overcome the secondary impacts of phosphates.
(s) Designs that propose anion-exchange
treatment shall include a pH/alkalinity feed system unless otherwise approved
by the Administrator.
(t)
Microscreens shall comply with the following requirements:
(i) A microscreen shall be allowed as a
supplement to treatment, but it shall not be used in place of filtration or
coagulation;
(ii) The screen shall
be capable of removing suspended matter from the water by straining;
(iii) Screens shall be made of
corrosion-resistant material;
(iv)
Bypass piping around the unit shall be provided;
(v) There shall be protection against back
siphonage when potable water is used for washing the screen; and
(vi) Wash water shall be wasted and not
recycled to the microscreen.
(u) Membrane technologies shall comply with
the following requirements:
(i) Proposed
membrane treatment processes shall comply with the requirements of Section
6 of this Chapter. Protocols for pilot
plant testing shall incorporate guidance or procedures from the US EPA Membrane
Filtration Guidance Manual, Chapter 6.
(ii) All proposed membrane filters shall
demonstrate third-party validation for the removal of Giardia or
Cryptosporidium. Removal efficiency shall be determined through challenge
testing as outlined in the US EPA Membrane Filtration Guidance Manual and one
of the following:
(A) Membranes that are used
as final compliance filters of a multiple treatment barrier approach shall meet
the requirements of 40 CFR Part 141; or
(B) All surface water or groundwater under
direct influence (GWUDI) systems using membrane technology shall demonstrate
minimum disinfection that meets 4.0-log virus inactivation.
(v) Facilities that
propose bag and cartridge filters shall comply with the procedures identified
in Section
6 of this Chapter and the following
requirements:
(i) Filter performance will be
based on Cryptosporidium oocyst removal;
(ii) The filter shall demonstrate at least a
3-log removal of particle size 1 micron and above with an associated log
reduction credit of 2-logs for Giardia and Cryptosporidium;
(iii) Removal efficiency shall be determined
through challenge testing as outlined in Toolbox Guidance Manual, Chapter 8 and
NSF/ANSI 419-2018;
(iv) The
performance demonstration shall be specific to the corresponding housing and
type or model of filter. Any other combination of housing and filter that could
be used for treatment shall also demonstrate filter efficiency;
(v) Applicants shall include documentation
that the proposed bag or cartridge filter has received third-party validation
for the removal of Giardia and Cryptosporidium;
(vi) Filter and housing specifications shall
include a description of the materials of construction, surface area per
filter, and the minimum and maximum operating pressure, and the specifications
shall meet the requirements of NSF/ANSI 419-2018 and the Toolbox Guidance
Manual, Chapter 8;
(vii) System
components such as housing, bags, cartridges, gaskets, and O-rings shall comply
with NSF/ANSI/CAN 61 for leaching of contaminants;
(viii) A means for monitoring the performance
of the filter shall be provided and shall include at a minimum flow meters and
valves, pressure gauges, and sample taps;
(ix) The proposed design shall specify
chemical compatibility limitations;
(x) A minimum of two filter housings shall be
provided;
(xi) Bag or cartridge
filters that are used as final compliance filters of a multiple treatment
barrier approach shall meet the requirements of 40 CFR Part 141; and
(xii) All surface water or GWUDI systems
using bag or cartridge filter technology shall provide at minimum disinfection
that meets 4.0-log virus inactivation and 1.0-log Giardia inactivation or shall
demonstrate that combined filtration and disinfection will provide 3-log
removal.
(w)
Pre-engineered water treatment plants shall comply with the following
requirements:
(i) Pre-engineered water
treatment plants shall be permitted on a case-by-case basis for specific
process applications and flow rates. Multiple units may be installed in
parallel to accommodate flow rates;
(ii) Pre-engineered water treatment plant
equipment shall be designed in accordance with NSF/ANSI/CAN 61 and NSF/ANSI/CAN
372;
(iv) Pre-engineered water
treatment plants shall comply with the procedures in Section
6 of this Chapter to obtain data that
demonstrates the treatment effectiveness of the treatment for the source water
and the proposed application; and
(v) Each component and process of the
pre-engineered water treatment plant shall demonstrate compliance with the
applicable design criteria of the respective treatment processes of this
Chapter.
(x) Wastes shall
be handled and disposed of as follows:
(i)
The sanitary and laboratory waste from water treatment plants, pumping
stations, or well systems, shall not be recycled to any part of the water
plant, and shall be discharged directly into a sanitary sewer when feasible or
a permitted on-site disposal system;
(ii) Brine waste from ion exchange plants,
demineralization plants, and other similar facilities may not be recycled to
the water plant and shall meet the following requirements:
(A) Where discharging to a sanitary sewer, a
holding tank shall be provided to prevent the overloading of the sewer and
interference with the waste treatment process; and
(B) Where disposal to an off-site waste
treatment system is proposed, the sewer and treatment facility shall have the
required capacity and dilution capability.
(iii) Acceptable methods of treatment and
disposal of lime softening sludge are:
(A)
Sludge lagoons, provided that the design of sludge lagoons includes:
(I) The location of the lagoon shall be
protected from the 100-year flood;
(II) A means of diverting surface water
runoff so that it does not flow into the lagoon;
(III) The freeboard shall be a minimum of
three feet;
(IV) An adjustable
decanting device for recycling the overflow; and
(V) An accessible effluent sampling
point.
(B) Land
application of liquid lime softening sludge that demonstrates compliance with
Water Quality Rules Chapter 11, Part E;
(C) Disposal at a landfill;
(D) Mechanical dewatering of sludge may be
used;
(E) Recalcination of sludge
may be used; and
(F) Lime sludge
drying beds shall not be allowed.
(iv) Acceptable methods of treatment and
disposal of alum sludge are as follows:
(A)
Lagoons may be used as storage and interim disposal. Lagoons used for storage
shall have a volume of at least 100,000 gallons for every 1,000,000 gpd of
facility water treating capacity.
(B) Alum sludge may be discharged to the
sanitary sewer only when the system is capable of handling the waste and with
the approval of the owner of the sewer system.
(C) Mechanical dewatering may be
used.
(D) Alum sludge drying beds
may be used.
(E) Alum sludge may be
acid-treated and recovered.
(F)
Disposal at a landfill.
(v) Designs that propose disposal of waste
filter wash water from iron and manganese removal plants that include sand
filters shall demonstrate the inclusion of a separate structure, unless
otherwise approved by the Administrator.
