La. Admin. Code tit. 51 § XII-1125

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

Section XII-1125 - Disinfection Monitoring

A. CT Parameters Monitoring. To determine compliance with disinfection inactivation requirements specified in Table 2 of §1115. B.1 of this Chapter, each supplier shall develop and conduct a monitoring program to measure those parameters that affect the performance of the disinfection process. This shall include but not be limited to:

1. temperature of the disinfected water at each residual disinfectant concentration sampling point;

2. pH(s) of the disinfected water (if free chlorine is used as a disinfectant) at each free chlorine residual disinfectant concentration sampling point;

3. the disinfectant contact time(s) at peak hourly flow at each residual disinfectant concentration sampling point;

4. the residual disinfectant concentrations before or at the first customer during peak hourly flow; and

5. if the system uses more than one point of disinfectant application before the first customer, the system must determine the parameters identified in Paragraphs 1-4 of this Subsection for each individual disinfection segment immediately prior to the next point of disinfectant application during peak hourly flow so that a cumulative CT value can be determined before the treated water reaches the first customer.

(NOTE: If the treatment plant uses its own finished water for potable purposes, the first customer may be the treatment plant itself.)

B. Disinfectant Residual Monitoring at Plant. To determine compliance with the performance standards specified in §1115 of this Chapter, the disinfectant residual concentrations of the water being delivered to the distribution system shall be measured and recorded continuously. The accuracy of disinfectant measurements obtained from continuous disinfectant monitors shall be validated at least weekly in accord with §1109. B or C, as applicable, of this Chapter. If there is a failure of continuous disinfectant residual monitoring equipment, grab sampling every two hours shall be conducted in lieu of continuous monitoring, but for no more than five working days following the failure of the equipment. Failure to have the continuous monitoring equipment replaced or repaired and put back into continuous service following the five working days allowed herein shall be deemed to constitute a violation of this Chapter. Systems shall maintain the results of disinfectant residual monitoring for at least 10 years.

C. Small System Disinfectant Residual Monitoring at Plant. Suppliers serving fewer than 3,300 people may collect and analyze grab samples of the water being delivered to the distribution system for disinfectant residual determination each day in lieu of the continuous monitoring, in accordance with Table 4 of this Chapter, provided that any time the residual disinfectant falls below 0.5 mg/l free chlorine or 0.5 mg/l chloramine residual (measured as total chlorine), the supplier shall take a grab sample every two hours until the residual concentrations is equal to or greater than 0.5 mg/l free chlorine or 0.5 mg/l chloramine residual (measured as total chlorine).

Table 4 (Applicable to Systems Serving less than 3,300 Individuals)
Disinfectant Residual Sampling
	System Population	Samples/Day
	# 500	1
	501-1,000	2
	1,001-2,500	3
	2,501-3,300	4

D. Disinfectant Residual Monitoring in Distribution System. The residual disinfectant concentrations in the distribution system shall be measured, recorded, and maintained in accordance with §367 B, C, D and E of this Part. A monitoring plan shall be developed, submitted, reviewed, and approved in accordance with §367. E of this Part.

La. Admin. Code tit. 51, § XII-1125

Promulgated by the Department of Health and Hospitals, Office of Public Health, LR 28:1342 (June 2002), amended LR 28:2523 (December 2002), LR 35:1243 (July 2009), Amended LR 42412 (3/1/2016).

AUTHORITY NOTE: Promulgated in accordance with R.S. 40:4(A)(8)(13) and R.S. 40:5(2)(3)(5)(6)(17)(20).