SECTION 252:626-11-3. Facility design

(a)   Number of feeders.

(1)   Where chemical feed is necessary for the public health protection, such as chlorination, coagulation or other essential processes:

(A)   provide a minimum of 2 feeders for each chemical applied,

(B)   design the feed system to meet the maximum chemical demand with the largest unit out of service, and

(C)   where a booster pump is required for feeder operation, provide duplicate pumps.

(2)   Provide adequate spare parts for feed equipment.

(b)   Control.

(1)   Feeders may be manually or automatically controlled. Automatic controls must include a manual override.

(2)   Provide control equipment to keep feed rates proportional to the plant flow rate.

(3)   Provide flow measurement to determine chemical feed rates.

(4)   Make provisions for measuring quantities of chemicals applied.

(5)   Equip feeders with alarm devices to warn operators of failures.

(c)   Dry chemical feeders.

(1)   Provide for measurement of chemicals either volumetrically or gravimetrically.

(2)   Feeders must be accurate to within 5% of any desired feed rate.

(3)   Provide adequate solution water and agitation in the solution pot.

(4)   Provide gravity feed from solution pots.

(5)   Completely enclose chemicals to prevent emission of dust to the operating room.

(6)   Do not use positive displacement solution feed pumps to feed chemical slurries.

(d)   Dust control.

(1)   Make provisions for the proper transfer of dry chemicals from shipping containers to storage bins or hoppers in order to minimize dust by using:

(A)   vacuum pneumatic equipment (dust collectors),

(B)   facilities designated for disposal of used shipping bags, or

(C)   closed conveyor systems.

(2)   Make provisions for wet mopping and for wiping of equipment, to remove any fluoride dusts, which might accumulate, unless a suitable type of vacuum cleaner is available for keeping the floor and equipment free from dust.

(3)   Provide a floor drain.

(4)   Equip all dry feeders with an enclosed hopper or cover to minimize dust problems.

(5)   Use crystalline or granular forms of fluoride compounds in dry feeders when applicable.

(e)   Liquid chemical feeders.

(1)   Provide positive displacement solution feed pumps to feed liquid chemicals.

(2)   Feeders must be accurate to within 5% of any desired feed rate.

(3)   Design and install liquid chemical feeders to prevent the siphonage of chemical solution into the public water supply.

(f)   Chemical feed equipment location. Chemical feed equipment must:

(1)   be located in a separate room to reduce hazards and dust problems,

(2)   be conveniently located near points of application to minimize length of feed lines, and

(3)   be readily accessible for servicing, repair, and observation of operation.

(g)   Storage of chemicals.

(1)   Provide space for dry storage of at least a 30-day supply of chemicals.

(2)   Separate the chemical storage rooms from the feed machine room. Liquid chemicals may be stored in the feed machine rooms where containment for spills is provided.

(3)   Use storage tanks and pipelines for liquid chemicals specific to the intended chemicals.

(4)   Provide liquid chemical storage tanks with:

(A)   a device to measure the liquid level in the tank, and

(B)   an overflow and a receiving basin or drain capable of receiving accidental spills or overflows.

(h)   Solution tanks.

(1)   Provide a measuring device to measure chemical addition and dilution water to maintain a uniform strength of solution.

(2)   Provide continuous agitation to maintain slurries in suspension.

(3)   Design solution tanks of adequate volume to assure continuity of supply in servicing a solution tank.

(4)   Provide a device to measure the solution level in the tank.

(5)   Keep chemical solution tanks covered.

(6)   Design large tanks with access openings that are curbed and fitted with tight overhanging covers.

(7)   Subsurface locations for solution tanks must:

(A)   be free from sources of possible contamination, and

(B)   assure positive drainage for ground waters, accumulated water, chemical spills and overflows.

(8)   Overflow pipes must:

(A)   be turned downward, with the end screened,

(B)   have freefall discharge, and

(C)   discharge through an air gap at least 6 inches or two pipe diameters whichever is greater above to an approved drain or containment area

(9)   Vent acid storage tanks to the outside atmosphere, but not through vents in common with day tanks.

(10)   Provide each tank with a valved drain, protected against backflow and cross-connection.

(11)   Have an overflow and a receiving basin capable of receiving accidential spills or overflows without uncontrolled discharge; 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.

(12)   Properly label tanks with the name of chemicals contained.

(i)   Day tanks.

(1)   Provide day tanks where design includes bulk storage of liquid chemical.

(2)   Design day tanks to meet all the requirements of Section 252:626-11-3(h).

(3)   Design day tanks to hold no more than a 30-hour supply.

(4)   Day tanks must be scale-mounted, or have a calibrated gauge painted or mounted on the side if liquid level can be observed in a gauge tube or through translucent side walls of the tank. In opaque tanks, a gauge rod extending above a reference point at the top of the tank, attached to a float is allowed. 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.

(5)   Provide hand pumps for liquid chemical transfer from a carboy or drum.

(6)   Where motor-driven transfer pumps are provided, provide a liquid level limit switch and an overflow from the day tank, which will drain by gravity back into the bulk storage tank.

(7)   Tank refilling line entry points shall be clearly labeled with the name of the chemicals contained.

(j)   Feed lines. Design feed lines to:

(1)   be as short as possible,

(2)   be of durable, corrosion resistant material,

(3)   be easily accessible throughout the entire length. Provide access to lines in floors or walks,

(4)   be protected against freezing,

(5)   be readily cleanable, open flumes are required for carrying suspensions of lime,

(6)   have adequate flow velocity in the lines to keep the chemical in suspension,

(7)   slope upward from the chemical source to the feeder when conveying gases,

(8)   be designed consistent with scale-forming or solids depositing properties of the water, chemical, solution or mixture conveyed,

(9)   be color-coded, per Appendix A, and

(10)   keep chemicals from being located overhead.

(k)   Handling.

(1)   Provide carts, elevators or other appropriate means for lifting chemical containers.

(2)   Make provisions for disposing of empty bags, drums or barrels by an approved procedure, which will minimize exposure to dusts.

(3)   Make provisions for the proper transfer of dry chemicals from shipping containers to storage bins or hoppers to minimize dust. Provide control by using one of the following:

(A)   vacuum pneumatic equipment or closed conveyor systems,

(B)   facilities for emptying shipping containers in special enclosures, or

(C)   exhaust fans and dust filters that can put the hoppers or bins under negative pressure.

(l)   Housing.

(1)   Construct floor surfaces to be smooth, impervious, slip-proof and with a minimum slope of 2.5 percent to an approved drain or containment area.

(2)   Discharge vents from feeders, storage facilities and equipment exhaust to the outside atmosphere above grade and remote from air intakes.

[Source: Added at 18 Ok Reg 1612, eff 6-1-01; Amended at 25 Ok Reg 2304, eff 7-11-08]