(1) Standards.
Chemicals used in the treatment of surface water shall
achieve the following:
(a) Primary
coagulant chemicals shall be utilized to permit the formation of a
floc,
(b) Disinfectants shall be
added to raw and/or treated water.
(2) Application Criteria.
In achieving these goals the chemical(s) shall be applied to
the water:
(a) To assure maximum
control and flexibility of treatment,
(b) To assure maximum safety to consumer and
operators,
(c) To prevent backflow
or back-siphonage of chemical solutions to finished water systems.
(d) With appropriate spacing of chemical feed
to eliminate any interference between chemicals.
(3) Typical Chemical Doses.
Chemical doses shall be estimated for each treatment plant to
be designed. "Jar tests" shall be conducted on representative raw water samples
to determine anticipated doses.
(4) Information Required for Review.
With respect to chemical applications, a submittal for
Division review and Director approval shall include:
(a) Descriptions of feed equipment, including
maximum and minimum feed rates,
(b)
Location of feeders, piping layout and points of application,
(c) Chemical storage and handling
facilities,
(d) Specifications for
chemicals to be used,
(e) Operating
and control procedures including proposed application rates,
(f) Descriptions of testing equipment and
procedures, and
(g) Results of
chemical, physical, biological and other tests performed as necessary to define
the optimum chemical treatment.
(5) Quality of Chemicals.
All chemicals added to water being treated for use in a
public water system for human consumption shall comply with ANSI/NSF Standard
60. Evidence for this requirement shall be met if the chemical shipping
container labels or material safety data sheets include:
(a) Chemical name, purity and concentrations,
Supplier name and address, and
(b)
Labeling indicating compliance with ANSI/NSF Standard 60.
(6) Storage, Safe Handling and Ventilation of
Chemicals.
All requirements of the Utah Occupational Safety and Health
Act (UOSHA) for storage, safe handling and ventilation of chemicals shall apply
to public drinking water facilities. The designer shall incorporate all
applicable UOSHA standards into the facility design, however, review of
facility plans by the Director under this Rule shall be limited to the
following requirements:
(a) Storage of
Chemicals.
(i) Space shall be provided for:
(A) An adequate supply of
chemicals,
(B) Convenient and
efficient handling of chemicals,
(C) Dry storage conditions.
(ii) Storage tanks and pipelines
for liquid chemicals shall be specific to the chemicals and not for
alternates.
(iii) Chemicals shall
be stored in covered or unopened shipping containers, unless the chemical is
transferred into a covered storage unit.
(iv) Liquid chemical storage tanks must:
(A) Have a liquid level indicator,
and
(B) Have an overflow and a
receiving basin or drain capable of receiving accidental spills or overflows,
and meeting all requirements of
R309-525-23,
and
(C) Be equipped with an
inverted "J" air vent.
(v) Acids shall be kept in closed
acid-resistant shipping containers or storage units.
(b) Safe Handling.
(i) Material Safety Data Sheets for all
chemicals utilized shall be kept and maintained in prominent display and be
easily accessed by operators.
(ii)
Provisions shall be made for disposing of empty bags, drums or barrels by an
acceptable procedure which will minimize operator exposure to dusts.
(iii) Provisions shall be made for measuring
quantities of chemicals used to prepare feed solutions.
(c) Dust Control and Ventilation.
Adequate provision shall be made for dust control and
ventilation.
(7)
Feeder Design, Location and Control.
(a)
General Feeder Design.
General equipment design, location and control shall be such
that:
(i) feeders shall supply, at all
times, the necessary amounts of chemicals at an accurately controlled rate,
throughout the anticipated range of feed,
(ii) chemical-contact materials and surfaces
are resistant to the aggressiveness of the chemicals,
(iii) corrosive chemicals are introduced in a
manner to minimize potential for corrosion,
(iv) chemicals that are incompatible are not
fed, stored or handled together.
(v) all chemicals are conducted from the
feeder to the point of application in separate conduits,
(vi) spare parts are available for all
feeders to replace parts which are subject to wear and damage,
(vii) chemical feeders are as near as
practical to the feed point,
(viii)
chemical feeders and pumps operate at no lower than 20 percent of the feed
range,
(ix) chemicals are fed by
gravity where practical,
(x) be
readily accessible for servicing, repair, and observation.
(b) Chemical Feed Equipment.
Where chemical feed is necessary for the protection of the
consumer, such as disinfection, coagulation or other essential
processes:
(i) a minimum of two
feeders, one active and one standby, shall be provided for each
chemical,
(ii) the standby unit or
a combination of units of sufficient capacity shall be available to replace the
largest unit during shut-downs,
(iii) where a booster pump is required,
duplicate equipment shall be provided and, when necessary, standby
power,
(iv) a separate feeder shall
be used for each non-compatible chemical applied where a feed pump is required,
and
(v) spare parts shall be
available for all feeders to replace parts which are subject to wear and
damage.
(c) Dry Chemical
Feeders.
Dry chemical feeders shall:
(i) measure feed rate of chemicals
volumetrically or gravimetrically, and
(ii) provide adequate solution water and
agitation of the chemical in the solution tank.
(d) Feed Rate Control.
(i) Feeders may be manually or automatically
controlled, with automatic controls being designed to allow override by manual
controls.
(ii) Chemical feed rates
shall be proportional to flows.
(iii) A means to measure water flow rate
shall be provided.
(iv) Provisions
shall be made for measuring the quantities of chemicals used.
(v) Weighing scales:
(A) shall be provided for weighing cylinders
at all plants using chlorine gas,
(B) may be required for fluoride solution
feed, where applicable,
(C) shall
be provided for volumetric dry chemical feeders, and
(D) shall be accurate to measure increments
of 0.5 percent of scale capacity.
(8) Feeder Appurtenances.
(a) Liquid Chemical Solution Pumps.
Positive displacement type solution feed pumps shall be used
to feed liquid chemicals, but shall not be used to feed chemical slurries.
Pumps must be sized to match or exceed maximum head conditions found at the
point of injection. All liquid chemical feeders shall be provided with devices
approved by the Utah Plumbing Code which will prevent the siphoning of liquid
chemical through the pump.
(b) Solution Tanks.
(i) A means consistent with the nature of the
chemical solution shall be provided in a solution tank to maintain a uniform
strength of solution. Continuous agitation shall be provided to maintain
slurries in suspension.
(ii) Means
shall be provided to measure the solution level in the tank.
(iii) Chemical solutions shall be kept
covered. Large tanks with access openings shall have the openings curbed and
fitted with tight overhanging covers.
(iv) Subsurface locations are discouraged,
but when used for solution tanks shall:
(A)
be free from sources of possible contamination, and
(B) assure positive drainage for ground
waters, accumulated water, chemical spills and overflows.
(v) Overflow pipes, when provided, shall:
(A) have a free fall discharge, and
(B) be located where noticeable.
(vi) Acid storage tanks shall be
vented to the outside atmosphere, but not through vents in common with day
tanks.
(vii) Each tank shall be
provided with a valved drain, protected against backflow in accordance with
R309-525-11(10)(b) and R309-525-11(10)(c).
(viii) Solution tanks shall be located and
protective curbing provided so that chemicals from equipment failure, spillage
or accidental drainage shall not enter the water in conduits, treatment or
storage basins.
(ix) When polymers
are used, storage tanks shall be located away from heat sources and direct
sunlight.
(c) Day Tanks.
(i) Day tanks shall be provided where
dilution of liquid chemical is required prior to feeding.
(ii) Day tanks shall meet all the
requirements of R309-525-11(9)(b).
(iii) Certain chemicals, such as polymers,
become unstable after hydration, therefore, day tanks shall hold no more than a
thirty hour supply unless manufacturer's recommendations allow for longer
periods.
(iv) Day tanks shall be
scale-mounted, or have a calibrated gauge painted or mounted on the side if
liquid levels cannot be observed in a gauge tube or through translucent
sidewalls of the tank. In opaque tanks, a gauge rod extending above a
referenced point at the top of the tank, attached to a float may be used. The
ratio of the cross- sectional area of the tank to its height must be such that
unit readings are meaningful in relation to the total amount of chemical fed
during a day.
(v) Hand pumps may be
provided for transfer from a carboy or drum. A top rack may be used to permit
withdrawal into a bucket from a spigot. Where motor-driven transfer pumps are
provided a liquid level limit switch and an overflow from the day tank, which
will drain by gravity back into the bulk storage tank, must be provided, unless
spill containment is provided for both bulk and day tanks.
(vi) A means which is consistent with the
nature of the chemical solution shall be provided to maintain uniform strength
of solution in a day tank. continuous agitation shall be provided to maintain
chemical slurries in suspension.
(vii) Tanks shall be properly labeled to
designate the chemical contained.
(d) Feed Lines.
(i) Feed lines shall be as short as possible
in length of run, and be:
(A) of durable,
corrosion resistant material,
(B)
easily accessible throughout the entire length,
(C) protected against freezing, and
(D) readily cleanable.
(ii) Feed lines shall slope upward from the
chemical source to the feeder when conveying gases.
(iii) Lines shall be designed with due
consideration of scale forming or solids depositing properties of the water,
chemical, solution or mixture conveyed.
(9) Make up Water Supply and Protection.
(a) In Plant Water Supply.
In plant water supply shall be:
(i) Ample in supply, adequate in pressure,
and of a quality equal to or better than the water at the point of
application.
(ii) Provided with
means for measurement when preparing specific solution concentrations by
dilution.
(iii) Properly protected
against backflow.
(b)
Cross-Connection Control.
Cross-connection control shall be provided to assure
that:
(i) The make-up waterlines
discharging to solution tanks shall be properly protected from backflow as
required by the Utah Plumbing Code.
(ii) Liquid chemical solutions cannot be
siphoned through solution feeders into the process units as required in
R309-525-11(9)(c).
(iii) No direct
connection exists between any sewer and the drain or overflow from the feeder,
solution chamber or tank by providing that all pipes terminate at least six
inches or two pipe diameters, whichever is greater, above the overflow rim of a
receiving sump, conduit or waste receptacle.
(iv) Pre- and post-chlorination systems must
be independent to prevent possible siphoning of partially treated water into
the clear well. The water supply to each eductor shall have a separate shut-off
valve. No master shut off valve will be allowed.
(c) Liquid Chemical Feeders, Siphon Control.
Liquid chemical feeders shall be such that chemical solutions
cannot be siphoned into the process units, by:
(i) Assuring positive pressure at the point
of discharge,
(ii) Providing vacuum
relief,
(iii) Providing a suitable
air gap, or
(iv) Other suitable
means or combinations as necessary.
(10) Operator Safety.
Design of the plant shall be in accordance with the Utah
Occupational Safety and Health Act (UOSHA). The designer and public water
system management are responsible to see that they incorporate applicable UOSHA
standards into the facility design and operation. Review of facility plans by
the Division shall be limited to the following requirements:
(a) Floor surfaces shall be smooth and
impervious, slip-proof and well drained,
(b) At least one pair of rubber gloves, a
dust respirator of a type certified by the National Institute of Occupational
Safety and Health (NIOSH) for toxic dusts, an apron or other protective
clothing and goggles or face mask should be provided for each operator, A
deluge shower and/or eye washing device shall be installed where strong acids
and alkalis are used or stored.
(c)
A water holding tank that will allow water to reach room temperature should be
installed in the water line feeding the deluge shower and eye washing device.
Other methods of water tempering may be available.
(d) Adequate ventilation should be
provided.
(11) Design
for Specific Chemicals.
Design of the plant shall be in accordance with the Utah
Occupational Safety and Health Act (UOSHA). The designer and public water
system management are responsible to see that they incorporate applicable UOSHA
standards into the facility design and operation. Review of facility plans by
the Division shall be limited to the following requirements:
Acids and Caustics.
(i) Acids and caustics shall be kept in
closed corrosion-resistant shipping containers or storage units.
(ii) Acids and caustics shall not be handled
in open vessels, but shall be pumped in undiluted form from original containers
through suitable hose, to the point of treatment or to a covered day
tank.
Sodium Chlorite for Chlorine Dioxide Generation.
Proposals for the storage and use of sodium chlorite should
be approved by the Director prior to the preparation of final plans and
specifications. Provisions shall be made for proper storage and handling of
sodium chlorite to eliminate any danger of explosion.
(i) Sodium Chlorite Storage:
(A) Sodium chlorite shall be stored by itself
in a separate room and preferably should be stored in an outside building
detached from the water treatment facility. It shall be stored away from
organic materials which would react violently with sodium chlorite;
(B) The storage structures shall be
constructed of noncombustible materials;
(C) If the storage structure is to be located
in a area where a fire may occur, water shall be available to keep the sodium
chlorite area sufficiently cool to prevent decomposition from heat and
resultant potential explosive conditions.
(ii) Sodium Chlorite Handling:
(A) Care should be taken to prevent spillage;
(B) An emergency plan of operation
shall be available for the clean up of any spillage;
(C) Storage drums should be thoroughly
flushed prior to recycling or disposal.
(iii) Sodium Chlorite Feeders:
(A) Positive displacement feeders should be
provided;
(B) Tubing for conveying
sodium chlorite or chlorine dioxide solutions shall be Type 1 PVC, polyethylene
or materials recommended by the manufacturer;
(C) Feed lines shall be installed in a manner
to prevent formation of gas pockets and shall terminate at a point of positive
pressure;
(D) Check valves shall
be provided to prevent the backflow of chlorine into the sodium chlorite
line.
