Current through Vol. 41, No. 13, March 15, 2024
(a)
Equipment capacity. The following requirements are for the
chlorination of non-industrial wastewater. The equipment shall be capable of
supplying the following dosage as applicable:
(1) Trickling filter plant effluent - 10
mg/l;
(2) Activated sludge plant
effluent - 8 mg/l;
(3) Tertiary
filtration effluent - 6 mg/l;
(4)
Nitrified effluent - 6 mg/l; and
(5) Category 2 water reuse chlorination
systems - 12 mg/l or a dose sufficient to achieve high level disinfection for
water reuse requirements.
(b)
Chlorine mixing.
(1)
Mixing. The disinfectant
shall be mixed as rapidly as possible to ensure complete mixing.
(2)
Contact period. Provide the
following contact periods:
(A) For OPDES
permit compliance or Categories 3 and 4 water reuse chlorination systems,
provide a minimum contact period of 15 minutes at peak hourly wastewater flow
or maximum pumping rate after mixing.
(B) For Category 2 water reuse chlorination
systems, alone or in combination with UV, provide sufficient free chlorine
residual concentration at the end of the contact tank and modal contact time
sized using the anticipated design flow after mixing at a design temperature of
5 °C (41 °F) and a pH of 8.0 to meet the micro-organism log removal
requirements in
252:656-27-3(a)(6).
(3)
Contact tank.
Construct chlorine contact tanks to minimize short-circuiting. "Over-and-under"
or "end-around" baffling shall be provided to reduce short-circuiting. Design
the tanks for easy maintenance and cleaning without reducing the effectiveness
of disinfection. Provide duplicate tanks, mechanical scrapers or portable
deck-level vacuum cleaning equipment. Provide skimming devices on all contact
tanks, and provide for draining the tanks.
(c)
Gas chlorine equipment
rooms.
(1)
Separation. If
the building that houses the gas chlorine equipment is used for other purposes,
a gas-tight room shall be provided to separate the gas chlorination equipment
and chlorine cylinders from other parts of the building. Do not connect floor
drains from the chlorine room to floor drains from other rooms. Doors to this
room shall open only to the outside of the building, with panic hardware, at
ground level and allow easy access to all equipment. For one-ton chlorine
cylinders, separate the storage area from the feed area. Locate chlorination
equipment as close to the application point as is reasonably possible. Certify
the installation will meet OSHA standards, and that the doors and emergency
equipment are compatible with chlorine.
(2)
Inspection window. Install a
shatter resistant, clear glass, gas-tight window in an exterior door or
interior wall of the chlorinator room so the units can be viewed without
entering the room.
(3)
Heating. Heat disinfection equipment rooms to maintain at least 60
ºF. Protect the gas chlorine cylinders from excess heat, and maintain the
cylinders at essentially room temperature.
(4)
Ventilation. Provide
mechanical ventilation capable of one air change per minute for chlorine. The
entrance to the room exhaust duct shall be near the floor. The point of
discharge shall not contaminate inhabited areas or the air inlet to any
buildings. Locate fresh air inlets to provide cross ventilation with air and at
a temperature that will not adversely affect the chlorination equipment.
Discharge the chlorinator vent hose above-grade to the outside
atmosphere.
(5)
Electrical
controls. Locate fan and light switches outside the room near the
entrance. A labeled signal light indicating fan operation shall be provided at
each entrance when the fan can be controlled from more than one
point.
(d)
Water
supply. Provide an ample supply of water to operate the chlorinator and
protect it according to
252:656-9-2(b).
Back up any booster pumps according to the power requirements of
252:656-9-2(a).
(e)
Scales. Provide
corrosion-resistant scales to weigh chlorine gas cylinders. Provide at least a
platform scale. Provide a recording device for the weight of the chlorine gas
cylinders for installation where one-ton cylinders or larger are
used.
(f)
Containers.
One-ton containers or larger are required if more than 150 pounds of chlorine
per day is needed. Limit the withdrawal rate to 40 pounds per day per cylinder
for cylinders up to 150 pounds, and to 400 pounds per day for one-ton
cylinders.
(g)
Handling
equipment. For cylinders up to 150 pounds, provide securing restraints
and a hand-truck designed for the cylinders. For one-ton cylinders, provide:
(1) a hoist with 4,000-pound
capacity;
(2) a cylinder lifting
bar;
(3) a monorail or hoist with
sufficient lifting height to pass one cylinder over another; and
(4) a cylinder trunnion(s) to allow
exchanging the cylinders for proper connection.
(h)
Manifolds. Gaseous chlorine
cylinders may be connected to a manifold, only when all cylinders are
maintained at the same temperature or the system is designed for gas transfer
from a warm container to a cooler one. Do not connect liquid chlorine cylinders
to a manifold.
(i)
Leak
detection and controls. Provide an emergency response plan for chlorine
leaks. Provide a bottle of 56% ammonium hydroxide solution for detecting
chlorine leaks. Where one-ton containers are used, provide a leak repair kit
approved by the Chlorine Institute, include caustic soda solution reaction
tanks to absorb leaks. Provide automatic gas detection and related alarm
equipment. Air Pollution Control regulations may also require air scrubbing
equipment.
(j)
Evaporators. Demonstrate the required volume of chlorine can be
supplied.
(k)
Respiratory
protection. Where chlorine gas is handled, provide respiratory air-pac
protection equipment that meets the National Institute for Occupational Safety
and Health (NIOSH) standards. Store the equipment and operating instructions at
a convenient location outside the room where chlorine is used or stored. The
units shall use compressed air, with at least a 30-minute capacity, and be
compatible with units used by the local fire department. In the emergency
response plan, describe how to maintain the equipment.
(l)
Sodium hypochlorite. Follow
equipment standards in OAC
252:626-11-4(g).
(1)
On-site Generation of Sodium
Hypochlorite:(A)
Contact
Time. On-site generation is limited by the upper concentration of the
chlorine solution produced. Design should account for concentration limit where
contact time is required. Contact time is determined from free chlorine
concentration only.
(B)
Ventilation. A by-product of on-site generation is the formation
of hydrogen gas. Design shall meet the following:
(i) Ventilation shall be designed to take
suction from as near the ceiling as practical.
(ii) Ventilation piping shall slope towards
an outlet and in a manner that does not trap hydrogen gas.
(iii) Provide hydrogen gas sensing equipment
capable of interlocking with sodium hypochlorite generation
equipment.
(iv) System shall have
automatic turn off of the equipment in the event that one-half (1/2) the lower
explosive limit (LEL) is reached.
(v) Separate gas sensing equipment shall
interlock with the ventilation equipment. System shall automatically turn on in
the event that one-fourth (1/4) the LEL for hydrogen is reached.
(vi) Provide at least one hydrogen sensor for
any space that hydrogen gas is likely to accumulate.
(vii) Piping penetrating the roof must have a
"T" or an "L" shape and a 24 mesh corrosion resistant screen.
(C)
Pretreatment. To
avoid fouling of the electrolytic cell, a water softener or other pretreatment
method is required to prevent scaling during the process.
(D)
Brine Solution. The salt
used for the brine shall be high grade (99% pure) and shall be certified for
use by the NSF for electrochlorination (NSF Standard 60). Provide the
capability for diluting 12.5% bulk sodium hypochlorite to create less than one
percent (1%) solution.
(E)
Storage. Design shall meet the following:
(i) All chemical handling and storage shall
be in accordance with OAC 252:626-11
(ii) Provide at least two (2) tanks with
thirty (30) hours storage capacity at average daily for usage
solution.
(iii) Protect concrete
from corrosion.
(iv) Tanks shall be
located in a structure to prevent freezing of all system components.
(v) Tanks shall be clear or provide a sight
glass to determine brine level.
(F)
Waste Disposal. Design shall
be in accordance with OAC 252:626-13 to ensure proper disposal of the waste
stream.
(G)
Warranty.
Provide a two (2) year warranty and maintenance on all equipment.
(H)
Redundancy. Provide multiple
units to meet maximum daily demand with the largest unit out of
service.
(m)
Dechlorination. When dechlorination is required by DEQ, the
discharges shall have less than 0.1 mg/l total residual chlorine.
(1)
Equipment. Do not chlorinate
and dechlorinate with the same units. Handle aqueous solutions of sulphite or
bisulfite with positive displacement pumps. Sulfur dioxide
(SO2 ) feed equipment shall account for the property of
the gas to easily liquefy. With one-ton containers, take special precautions to
prevent chemicals from liquefying. Provide multiple units to meet the operating
requirements between the minimum and maximum wastewater flow rates and to avoid
depleting dissolved oxygen in receiving waters.
(2)
Mixing. Mechanical mixers
are required unless the design will provide hydraulic turbulence to assure
thorough and complete mixing.
(3)
Sulfonator water supply. Provide an ample supply of water to
operate the sulfonator, and protect it according to
252:656-9-2(b).
Back up booster pumps according to the power requirements of
252:656-9-2(a).
(4)
Housing. Storage and feed
equipment for SO2 shall be in a separate room from
chlorine gas storage and feed equipment. The same storage requirements apply to
SO2 as for chlorine gas in (c) of this Section. Mixing,
storage, and feed equipment areas shall be designed to contain spillage or
leakage or to route it to an appropriate containment unit.
(5)
Respiratory protection. Same
as for chlorine gas in (k) of this Section.
Added at 17 Ok Reg 1140,
eff 6-1-00; Amended at 23 Ok Reg 937, eff 6-15-06; Added at 28 Ok Reg 1282, eff
7-1-11
