La. Admin. Code tit. 51 § XII-203

Current through Register Vol. 50, No. 11, November 20, 2024

Section XII-203 - Feed Equipment

A. Feeder Redundancy. Where a chemical feed and booster pump is necessary for the protection of the supply, such as chlorination, coagulation or other essential processes, a standby unit or a combination of units of sufficient size to meet capacity shall be provided to replace the largest unit when out of service.

1. A separate feeder shall be used for each chemical applied.

2. Spare parts shall be available on site for each type of feeder and chemical booster pump to replace parts which are subject to wear and damage.

B. Control. Feeders may be manually or automatically controlled.

1. Automatic controls shall be designed so as to allow override by manual controls.

2. Chemical feed rates shall be proportional to the flow stream being dosed.

3. A means to measure the flow stream being dosed shall be provided in order to determine chemical feed rates.

4. Provisions shall be made for measuring the quantities of chemicals used.

5. Weighing scales:

a. shall be provided for weighing cylinders at all plants utilizing chlorine gas;

b. shall be required for fluoride solution fed from supply drums or carboys;

c. should be provided for volumetric dry chemical feeders;

d. shall be capable of providing reasonable precision in relation to average daily dose; and

e. shall not be required for chlorine gas cylinders when used as a backup or standby source of chlorine gas.

6. Where conditions warrant, for example with rapidly fluctuating intake turbidity, coagulant and coagulant aid addition may be made according to turbidity, streaming current or other sensed parameter.

C. Dry Chemical Feeders. Dry chemical feeders shall:

1. measure chemicals volumetrically (see §203. B.5.c of this Part) or gravimetrically;

2. provide adequate solution/slurry water and agitation of the chemical at the point of placing in solution/slurry; and

3. completely enclose chemicals to reduce emission of dust to the operating room.

D. Positive Displacement Solution Feed Pumps. Positive displacement type solution feed pumps should be used to feed liquid chemicals.

1. Pumps shall be capable of operating at the required maximum rate against the maximum head conditions found at the point of injection.

2. Equipment utilized to readily measure feed rates in the pumped liquid shall be designed to handle the liquid being measured and shall be provided.

3. A pressure relief valve should be provided on the pump discharge line.

E. Siphon Control for Liquid Chemical Feeders. Liquid chemical feeders shall be such that chemical solutions cannot be siphoned or overfed into the water supply, by:

1. assuring discharge at a point of positive pressure;

2. providing vacuum relief;

3. providing a suitable air gap, or anti-siphon device; or

4. providing other suitable means or combinations as necessary.

F. Cross-connection control shall be provided to assure that:

1. the service water lines discharging to liquid storage tanks shall be properly protected from backflow as required by the state health officer;

2. chemical solutions or slurries cannot be siphoned through liquid chemical feeders into the water supply as required in §203. E of this Part;

3. no direct connection exists between any sewer and a drain or overflow from the liquid chemical feeder, liquid storage chamber or tank by providing that all drains terminate at least six inches or two pipe diameters, whichever is greater, above the overflow rim of a receiving sump, conduit or waste receptacle;

4. in the absence of other cross connection control measures, separate feeders shall be provided for chemical feed systems that have feed points at both unfiltered and filtered water locations such that all unfiltered water feed points are fed from one feeder, and that all filtered water feed points are fed from another feeder.

G. Location. Chemical feed equipment:

1. shall be readily accessible for servicing, repair, and observation of operation;

2. should be located in a separate room if hazards and dust problems may exist; and

3. should be conveniently located near points of application to minimize length of feed lines.

H. In-plant water supply shall be:

1. ample in quantity and adequate in pressure;

2. provided with means for measurement when preparing specific solution concentrations by dilution;

3. properly treated for hardness, when necessary;

4. properly protected against backflow; and

5. obtained from the finished water supply, or from a location sufficiently downstream of any chemical feed point to assure adequate mixing.

I. Supply and Storage of Chemicals. A minimum of 10 days of chemical supply shall be on site at all times that will allow the facility to satisfy a maximum average day demand for all ten days. Additional supply of chemicals that will not degrade is recommended. Chemicals for which the EPA has established a threshold quantity for risk management plan purposes need not be stored on site provided the system has a plan in place for effective timely deliveries of such chemicals.

1. Storage space shall:

a. be convenient and provide for efficient handling of chemicals;

b. have dry storage conditions; and

c. provide a minimum storage volume of 1.5 truck loads where purchase can only be made by truck load lots.

2. Storage tanks and pipelines for liquid chemicals shall be specified for use with individual chemicals and not used for different chemicals. Off loading areas shall be clearly labeled to prevent accidental cross-contamination.

3. Chemicals shall be stored in covered or unopened shipping containers, unless the chemical is transferred into an approved storage unit.

4. Liquid chemical storage tanks shall:

a. have a means to readily determine the volume of liquid retained in the storage tank; and,

b. have an overflow and a receiving basin capable of receiving accidental spills or overflows without uncontrolled discharge; a common receiving basin may be provided for each group of compatible chemicals, which provides sufficient containment volume to prevent accidental discharge in the event of failure of the largest tank.

J. Bulk Liquid Storage Tanks. Bulk liquid storage tanks shall comply with the following requirements:

1. A means which is consistent with the nature of the chemical stored shall be provided in a liquid storage tank to maintain a uniform chemical strength. Continuous agitation shall be provided to maintain slurries in suspension.

2. A means to assure continuity of chemicals to treat the water to comply with federal primary drinking water standards and state drinking water regulations shall be provided while servicing a liquid storage tank.

3. A means shall be provided to readily measure the liquid level in the liquid storage tank.

4. Liquid storage tanks shall have a lid. Large liquid storage tanks with access openings shall have such openings curbed and fitted with overhanging covers or, bolted and gasketed manways.

5. Subsurface locations for liquid storage tanks shall:

a. be free from sources of possible contamination; and

b. assure positive drainage away from the area for ground waters, accumulated water, chemical spills and overflows.

6. Overflow pipes, when provided, shall:

a. be turned downward, with the end screened;

b. have a free fall discharge; and

c. be located where noticeable.

7. Liquid storage tanks must be vented, but not through vents in common with other chemicals or day tanks. Acid storage tanks shall be vented to the outside atmosphere.

8. Each liquid storage tank shall be provided with a method to be drained.

9. Each liquid storage tank shall be protected against contamination by cross-connections.

10. Liquid storage tanks shall be located and secondary containment provided so that chemicals from equipment failure, spillage or accidental drainage shall not enter the water in conduits, treatment or storage basins. Secondary containment volumes shall be able to hold the volume of the largest storage tank. Piping shall be designed to minimize or contain chemical spills in the event of pipe ruptures.

K. Overfeed Protection. Overfeed protection shall be provided and comply with the following requirements.

1. A LDH-approved overfeed process control and/or procedure shall be provided for liquid chemical feeds. The process control and/or procedure must be in addition to the requirements of §203. E (siphon control) of this Part. When day tanks are used for overfeed protection, day tanks shall meet requirements of §203. K.3 of this Part.

2. Day tanks shall be provided when bulk storage of fluoride is used.

3. When day tanks are used, all day tanks shall meet all of the following requirements and requirements of §203. J of this Part, except that shipping containers do not require §203. J.6 (overflow pipes) and §203. J.8 (drain method) and day tanks do not require secondary containment.

a. Day tanks should hold no more than a 30 hour supply.

b. Day tanks shall 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 sidewalls of the tank. In opaque tanks, a gauge rod may be used.

c. Except for fluorosilicic acid, hand pumps may be provided for transfer from a shipping container. A tip rack may be used to permit withdrawal into a bucket from a spigot.

d. A means which is consistent with the nature of the chemical solution shall be provided to maintain uniform chemical strength in a day tank. Continuous agitation shall be provided to maintain chemical slurries in suspension.

e. Tanks and tank refilling line entry points shall be clearly labeled with the name of the chemical contained.

f. Filling of day tanks shall not be automated, unless redundancy of controls is provided.

g. Where motor-driven transfer pumps are provided, an automated means to prevent an overflow shall be provided.

L. Feed Lines. Feed lines:

1. should be as short as possible;

2. should be of durable, corrosion-resistant material;

3. be easily accessible throughout the entire length;

4. be readily cleanable;

5. shall be protected from freezing;

6. should slope upward from the chemical source to the feeder when conveying gases;

7. shall be designed consistent with scale-forming or solids depositing properties of the water, chemical, solution or mixtures conveyed; and

8. should be color coded and labeled.

M. Handling. Carts, elevators and other appropriate means shall be provided for lifting chemical containers to minimize excessive lifting by operators.

1. Provisions shall be made for disposing of empty bags, drums, carboys, or barrels by an approved procedure which will minimize exposure to dusts.

2. Provisions shall 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 which may enter the room in which the equipment is installed. Control should be provided by use of:

a. vacuum pneumatic equipment or closed conveyor systems;

b. facilities for emptying shipping containers in special enclosures, and/or;

c. exhaust fans and dust filters.

3. Provision shall be made for measuring quantities of chemicals used to prepare feed solutions.

N. Housing. Housing of feed equipment shall comply with the following.

1. Floor surfaces shall be smooth and impervious, slip-proof and well drained.

2. Vents from feeders, storage facilities and equipment exhaust shall discharge to the outside atmosphere above grade and remote from air intakes.

La. Admin. Code tit. 51, § XII-203

Promulgated by the Department of Health, Office of Public Health, LR 44329 (2/1/2018), effective 8/1/2018.

AUTHORITY NOTE: Promulgated in accordance with the provisions of R.S. 40:4.A.(8), 40:4.13.D.(1)(2) and 40:5.A.(2)(3)(5)(6)(7)(17).