Current through Register Vol. 48, No. 38, September 20, 2024
a) Solution Feed Equipment
1) Corrosion-resistant containers must be
provided for solution feeders.
2)
Containers must have non-corrodible covers with overhanging edges. Openings
must be constructed to prevent contamination.
3) Scales or a volumetric measuring device
must be provided for determining the amount of solution fed.
b) Feeder Redundancy
1) When chemical feed is necessary for the
protection of the supply, such as chlorination, coagulation, or other essential
processes:
A) a minimum of two feeders must be
provided with each having adequate capacity to provide the maximum dosage
necessary; and
B) the standby unit
or a combination of units of sufficient size to meet capacity must be provided
to replace the largest unit when out of service.
2) A separate feeder must be used for each
chemical applied.
3) Each chemical
feeder and day tank must be identified with its content.
4) Spare parts must be available on site for
all feeders and chemical booster pumps to replace parts that are subject to
wear and damage.
c)
Control
1) At automatically operated
facilities:
A) The automatic controls must be
designed to allow override by manual controls.
B) Chemical feeders must be electrically
interconnected with the well or service pump so that they will not operate if
the well or service pump is not operating.
2) Chemical feed rates must be proportional
to the flow stream to achieve the appropriate dose of chemical
application.
3) A means to measure
the water flow stream being dosed must be provided to determine chemical feed
rates.
4) Provisions must be made
for measuring the quantities of chemicals used.
5) Weighing Scales
A) Weighing scales must be capable of
providing reasonable precision for the average daily dose.
B) Unless otherwise approved by the Agency
under Section 604.145(b),
treatment chemicals in a gaseous state must be weighed;
C) Fluoride solution fed from supply drums or
carboys must be weighed; and
D)
Volumetric dry chemical feeders must be weighed unless otherwise approved by
the Agency under Section
604.145(b).
d) Dry chemical feeders
must:
1) measure chemicals volumetrically or
gravimetrically;
2) provide
adequate water and agitation of the chemical within the slurry tank;
and
3) completely enclose chemicals
to prevent the emission of dust to the operating room.
e) Positive Displacement Solution Pumps
1) Positive displacement type solution feed
pumps may be used to feed liquid chemicals, but must not be used to feed
chemical slurries.
2) Pumps must be
capable of operating at the required maximum rate against the maximum head
conditions found at the point of injection.
3) Calibration tubes or mass flow monitors
that allow for direct physical measurement of actual feed rates must be
provided.
f) To ensure
that chemical solutions cannot be siphoned or overfed into the water supply,
liquid chemical feeders must:
1) assure
discharge at a point of positive pressure;
2) provide vacuum relief; or
3) provide a suitable air gap or anti-siphon
device.
g)
Cross-connection control must be provided to assure that:
1) the make-up water lines discharging to
liquid storage tanks must be properly protected from backflow;
2) no direct connection exists between any
sewer and a drain or overflow from a chemical feed system; and
3) all overflows and drains from a chemical
field system must have an air gap above the sewer or overflow rim of a
receiving sump.
h)
Chemical feed equipment location must be readily accessible for servicing,
repair, and observation of operation.
i) Make-up water lines must be:
1) obtained from the finished water supply,
or from a location sufficiently downstream of any chemical feed point to assure
adequate mixing; and
2) ample in
quantity and adequate in pressure.
j) Storage of Chemicals
1) Space must be provided for:
A) at least 30 days of chemical
supply;
B) convenient and efficient
handling of chemicals;
C) dry
storage conditions; and
D) a
minimum storage volume of
1.5 times the gross shipping
volume.
2) Offloading
areas must be clearly labeled to prevent accidental
cross-contamination.
3) Chemicals
must not be stored in confined spaces.
4) Chemicals must be stored in covered or
unopened shipping containers, unless the chemical is transferred into an
approved storage unit.
5) Feed
equipment and storage chemicals must be stored inside a building unless
otherwise approved by the Agency under Section
604.145(b).
6) Liquid chemical storage tanks must have a
liquid level indicator.
7)
Secondary Containment
A) Liquid chemical
storage tanks must have secondary containment consisting of an overflow and a
receiving basin capable of receiving accidental spills or overflows without
uncontrolled discharge.
B) A common
receiving basin may be provided for each group of compatible chemicals that
provides sufficient containment volume to prevent accidental discharge in the
event of failure of the largest tank. Groups of compatible chemicals are as
follows: acids, bases, salts and polymers, absorption powders, oxidizing
powders, and compressed gases.
8) Vents from storage tanks must have a
corrosion-resistant 24 mesh screen.
k) Bulk Liquid Storage Tanks
1) A uniform strength of chemical solution
must be maintained. Continuous agitation must be provided to maintain slurries
in suspension.
2) A means to assure
continuity of chemical supply must be provided.
3) Means must be provided to measure the
liquid level in the tank.
4) Liquid
storage tanks including any access openings must be kept securely
covered.
5) Overflow pipes, when
provided, must:
A) be turned downward, with
the end screened;
B) have a free
fall discharge; and
C) be located
where noticeable.
6)
Liquid storage tanks must be vented, but not through vents in common with other
chemicals or day tanks.
7) Each
liquid storage tank must be provided with a valved drain in accordance with
subsection (g).
8) Solution tanks
must be located, and protective curbings provided, so that chemicals from
equipment failure, spillage, or accidental drainage do not enter the water in
conduits or treatment or storage basins. Chemicals must be stored as required
by subsection (j)(5).
l)
Day Tanks
1) Day tanks must be provided where
bulk storage of liquid chemical is provided.
2) Day tanks must meet all the requirements
of subsection (k), except that shipping containers do not require overflow
pipes and subsection drains.
3) Day
tanks must be scale-mounted or, if the liquid level can be observed in a gauge
tube or through translucent sidewalls of the tank, have a calibrated gauge
painted or mounted on the side. In opaque tanks, a gauge rod may be used. The
ratio of the 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.
4) Except for fluosilicic
acid, hand pumps may be provided for transfer from a shipping container. When
motor driven transfer pumps are provided, a liquid level limit switch must be
provided.
5) Tanks and tank
refilling line entry points must be clearly labeled with the name of the
chemical contained.
6) Filling of
day tanks must not be automated.
m) Feed lines must be:
1) of durable, corrosion-resistant
material;
2) protected against
freezing;
3) designed to prevent
clogging; and
4) color-coded and
labeled in accordance with Section
604.120.
n) Handling. Provision must be made for the
proper transfer of dry chemicals from shipping containers to storage bins or
hoppers, in such a way as to minimize the quantity of dust that may enter the
room.
o) Housing
1) Floor surfaces must be smooth and
impervious, slip-proof, and well-drained.
2) Vents from feeders, storage facilities,
and equipment exhaust must discharge to the outside atmosphere above grade and
remote from air intakes.