| (a) All chemicals used to treat sludge must be compatible
with the operation of the sludge processing unit and must not adversely
affect any other treatment unit or the receiving waters.
(b) The engineering report must justify appropriate
chemicals and feed ranges. A pilot plant study or data from a treatment
unit must be used. The organic, metal, and hydraulic loadings at the
pilot plant must be within 25% of the design organic, metal, and hydraulic
loadings.
(c) Each chemical must be handled, stored, and disposed
of according to its safety data sheet.
(d) A liquid chemical storage tank must have:
(1) a liquid level indicator; and
(2) an emergency overflow receiving basin or drain
capable of retaining any spill.
(e) Powdered activated carbon must be stored in an
isolated fireproof area.
(f) A storage or handling area where potentially volatile
chemicals are present must have electrical outlets, lights, and motors
that meet the National Fire Protection Association 70 National Electrical
Code® in effect at the time the storage or handling area was constructed,
including explosion prevention requirements.
(g) Systems for transport, transfer, storage, and use
of any volatile chemical must prevent volatile chemicals from discharging
to the atmosphere.
(h) A wastewater treatment facility must have at least
a 30-day supply of each chemical in dry storage conditions, unless
the engineering report justifies a reduced amount.
(i) A solution storage tank or direct-feed day tank
must have sufficient capacity for operation at the design flow of
the wastewater treatment facility.
(j) The procedures for measuring the quantity of each
chemical used to prepare each feed solution must be included in the
wastewater treatment facility's operation and maintenance manual.
(k) A chemical storage tank, pipe, or other equipment
must be compatible with the chemical it is designed to handle.
(l) Chemicals must only be combined in a feed solution.
Intermixing of chemicals prior to preparing a feed solution is prohibited.
(m) Concentrated liquid acid must not be stored in
an open vessel, and must be pumped in undiluted form from the original
container to a point of treatment, to an enclosed acid-resistant day
tank, or to an enclosed acid resistant storage tank.
(n) Concentrated liquid acid must be kept in a closed,
acid-resistant shipping container or storage unit.
(o) The transfer of a toxic material must be controlled
by an actuating device.
(p) A wastewater treatment facility must have one or
more of the following control methods to ensure that dust will be
minimized during the transfer of a dry chemical:
(1) a closed conveyor system with vacuum pneumatic
equipment;
(2) a facility for emptying shipping containers in
a special enclosure; or
(3) an exhaust fan and dust filter that uses a hopper
or bin under negative pressure to eliminate chemical particles in
the air.
(q) Disposing of a chemical or an empty chemical container
must be done in a manner that minimizes the potential for harmful
exposure and in compliance with Chapter 335 of this title (relating
to Industrial Solid Waste and Municipal Hazardous Waste).
(r) A chemical delivery system must meet the following
requirements:
(1) Structures housing equipment.
(A) A floor surface must be smooth, slip resistant,
impervious, and must have a minimum slope of 1/8 inch per foot.
(B) An open basin, tank, or conduit must be protected
from a chemical spill or accidental drainage.
(C) An area that houses a chemical delivery system
must provide access for servicing, repair, and observation of operations.
(2) Redundancy. A chemical delivery system must have
at least two feeders and must be able to supply the amount of chemicals
needed for process reliability throughout the feed range. Chemical
delivery equipment must be able to maintain operation at design flow
with the largest operational unit out of service.
(3) Design and Capacity.
(A) A chemical delivery system must be able to deliver
a proportional amount of chemical feed based on the rate of flow.
(B) A chemical delivery system must not use positive
displacement type solution feed pumps to feed chemical slurries, unless
the engineering report justifies such use.
(C) If using potable water, the potable water supply
must be protected by at least the equivalent of two backflow preventers,
including at least one air gap between a supply pipe and a solution
tank.
(D) A chemical delivery system component must be resistant
to the chemical it is designed to apply.
(E) A dry chemical delivery system must:
(i) measure the chemical volumetrically or gravimetrically;
(ii) provide effective mixing and solution of the chemical
in a solution pot;
(iii) provide gravity feed from a solution pot;
(iv) completely enclose chemicals; and
(v) prevent emission of dust to the operation room.
(4) Spill Containment. The chemical delivery equipment
must have protective curbing to contain a chemical spill.
(5) Control Systems.
(A) All chemical delivery systems must have an automatic
control system that is capable of manual control.
(B) A chemical delivery system must have manual starting
equipment.
(C) A chemical delivery system may be designed with
an automatic chemical dose or residual analyzer.
(D) If an automatic chemical dosing or residual analyzer
is used, the design must require both recording charts and an alarm
for any critical value.
(6) Weighing Scales. A volumetric dry chemical feeder
or a non-volumetrically calibrated carboy must have weighing scales
that measure in increments of no greater than 0.5% of the load.
(7) Chemical Delivery System Protection. A chemical
delivery system must have freeze protection and must be accessible
for cleaning.
(8) Water Supply.
(A) A water supply for chemical mixing may be potable
water or reclaimed water.
(B) A chemical delivery system must protect its water
supply from contamination. If using potable water, the potable water
supply must be protected by at least the equivalent of two backflow
preventers, including at least one air gap between a supply pipe and
a solution tank.
(C) A water supply must have sufficient pressure to
ensure dependable operations.
(D) A water supply must include a means for measuring
solution concentrations.
(E) A water supply design must include sufficient duplicate
equipment to ensure process reliability.
(F) A water supply design may include a booster pump
to maintain water pressure.
(9) Solution Tanks.
(A) A solution tank must be able to maintain uniform
strength of solution consistent with the nature of the chemical solution
and must provide continuous agitation.
(B) A chemical delivery system must have at least two
solution tanks.
(C) The solution tank(s) must provide storage for at
least one full day of operation at design flow.
(D) A solution tank must have a drain and a solution
level indicator.
(E) An intake point for potable water must have an
air gap.
(F) A chemical solution tank must be covered and have
an access opening that is curbed and fitted with a tight cover.
(G) Each subsurface solution tank must:
(i) be impermeable;
(ii) be protected against buoyancy;
(iii) include a means to drain groundwater or other
accumulated water away from the tank;
(iv) include leak detection; and
(v) allow for containment and remediation of any chemical
spill.
(H) An emergency overflow pipe must:
(i) be turned downward;
(ii) have an unobstructed discharge;
(iii) be clearly visible;
(iv) drain to a containment area; and
(v) must not contaminate the wastewater or receiving
stream.
(10) Chemical Application.
(A) A chemical application system must be efficient
and operate safely.
(B) The chemical application system must prevent backflow
or back-siphoning between multiple points of feed through common manifolds.
(C) The application of a pH-affecting chemical to the
wastewater must be done before the addition of a coagulant.
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