La. Admin. Code tit. 51 § XII-183

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

Section XII-183 - Anion Exchange Treatment

A. Pre-Treatment Requirements. Iron, manganese or a combination of the two, should not exceed 0.3 mg/L in the water as applied to the ion exchange resin. Pre-treatment is required when a combination of iron and manganese exceeds 0.5 mg/L.

B. Design criteria for anion exchange treatment is as follows.

1. Anion exchange units are typically of the pressure type, down flow design. Automatic regeneration based on volume of water treated shall be used unless manual regeneration is justified and is approved by the state health officer. A manual override shall be provided on all automatic controls.

2. If a portion of the water is bypassed around the units and blended with treated water, the maximum blend ratio allowable must be determined based on the highest anticipated raw water contaminant level. If bypassing is provided, a totalizing meter and a proportioning or regulating device or flow regulating valves shall be provided on the bypass line.

C. Number of Units. At least two units shall be provided. The treatment capacity shall be capable of producing the water at the average daily flow at the maximum month of the plant at a level below the MCL of the contaminant being removed, with one exchange unit out of service.

D. Type of Media. The anion exchange media shall be of the type required to for the contaminant being removed.

E. Flow Rates. The treatment flow rate should not exceed 5 gallons per minute per square foot of bed area (20 cm/minute down flow rate). The backwash flow rate should be approximately 4.0 to 6.0 gallons per minute per square foot of bed area (16 to 24 cm/minute rise rate). The regeneration rate should be approximately 1.0 gallon per minute per square foot of bed area (4 cm/minute rise rate) with a fast rinse approximately equal to the service flow rate.

F. Freeboard. Adequate freeboard shall be provided to accommodate the backwash flow rate of the unit.

G. Miscellaneous Appurtenances. Miscellaneous appurtenances shall include the following.

1. The system shall be designed to include an adequate under drain and supporting gravel system and brine distribution equipment.

2. Sample taps, and brine and salt storage shall be as required in §181. B 12 and §181. B 13 of this Part.

H. Cross Connection Control. Backwash, rinse and air relief discharge pipes shall be installed in such a manner as to prevent any possibility of back-siphonage.

I. Construction Materials. Pipes and contact materials must be resistant to the aggressiveness of salt. Plastic and red brass are acceptable materials. Steel and concrete shall be coated with a non-leaching protective coating which is compatible with salt and brine.

J. Housing. Bagged salt and dry bulk salt storage shall be enclosed and separated from other operating areas in order to prevent damage to equipment.

K. Preconditioning of the Media. Prior to startup of the equipment, the media shall be regenerated with no less than two bed volumes of water containing sodium chloride followed by an adequate rinse.

L. Waste Disposal. Suitable disposal must be provided for brine waste (see Subchapter F. §257-275 of this Part).

La. Admin. Code tit. 51, § XII-183

Promulgated by the Department of Health, Office of Public Health, LR 44323 (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).