La. Admin. Code tit. 51 § XII-1123

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

Section XII-1123 - Filtration Monitoring

A. Source Water Turbidity Monitoring. Each supplier using surface water or GWUDISW as a source of water supply shall monitor the turbidity level of the raw water source by taking and analyzing no less than one grab sample per day. Continuous turbidity monitoring may be substituted provided the accuracy of the measurements are validated weekly in accord with §1107. D of this Chapter. If there is a failure in the continuous turbidity monitoring equipment, the system shall collect and analyze no less than one grab sample per day. Systems shall maintain the results of raw water turbidity monitoring for at least three years.

B. Settled Water Turbidity Monitoring

1. Each supplier using surface water as its source of water supply should monitor and record settled water turbidity prior to filtration in each individual treatment train at least once every four hours.

2. Each supplier using GWUDISW as its source of water supply should, if filtration is required or otherwise performed, monitor and record settled water turbidity prior to filtration in each individual treatment train at least once every four hours.

C. Combined Filter Effluent Turbidity Monitoring. To determine compliance with the performance standards specified in §1115 of this Chapter, each supplier using surface water or GWUDISW shall conduct continuous turbidity monitoring of representative samples of the combined filter effluent prior to clearwell storage during all times that the system is in operation. Combined filter effluent turbidity measurements shall be recorded every 15 minutes. The accuracy of the turbidity measurements from the continuous turbidity monitor shall be validated weekly in accord with §1107. D of this Chapter. If there is a failure in the continuous turbidity monitoring equipment, the system shall collect and analyze a grab sample every two hours 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 combined filter effluent turbidity monitoring for at least three years.

EXCEPTION: In the case of public water systems using surface water or GWUDISW and serving less than 10,000 individuals, if there is a failure in the continuous turbidity monitoring equipment, the system shall collect and analyze a grab sample every four hours in lieu of continuous monitoring, but for no more than five working days following the failure of 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 combined filter effluent turbidity monitoring for at least three years.

1. In existing treatment plants which may not have a combined filter effluent point prior to clearwell storage or other design limitations, DHH may, on a case-by-case basis, allow turbidity compliance monitoring to be performed at an alternate sampling point which is determined to be representative of the system's filtered water (in accordance with Section 5.2 1 of the SWTR Guidance Manual). Requests to utilize an alternate turbidity monitoring sampling point for compliance monitoring shall be submitted in writing to DHH for review and approval.

2. In existing treatment plants which do not have a combined filter effluent point prior to clearwell storage, have at least four or more active filters, and which have been approved by DHH (pursuant to §1123. C.1 of this Chapter) to determine compliance with the turbidity performance standards specified in §1115 of this Chapter by using the average of measurements from each filter effluent shall, when there is a failure in the continuous turbidity monitoring equipment, only be required to collect and analyze a grab sample every four hours (in lieu of continuous monitoring and the normal every two hour grab sampling requirement specified in §1123. C of this Chapter), 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.

D. Slow Sand or Small System Turbidity Monitoring. Suppliers using surface water or GWUDISW and utilizing slow sand filtration or serving fewer than 500 people may reduce turbidity monitoring to one raw water and one combined filter effluent grab sample per day if DHH determines that less frequent monitoring is sufficient to indicate effective filtration performance.

E. Individual Filter Turbidity Monitoring/Additional Actions

1. Monitoring Individual Filters for Turbidity. Public water systems using surface water or GWUDISW as its source of water supply and which utilizes conventional filtration treatment or direct filtration shall conduct continuous turbidity monitoring for each individual filter. Such systems shall record the results of individual filter monitoring every 15 minutes while the filter is in service. The accuracy of the turbidity measurements from the continuous turbidity monitor shall be validated weekly in accord with §1107. D of this Chapter. If there is a failure in the continuous turbidity monitoring equipment, the system shall conduct grab sampling every four hours in lieu of continuous monitoring, but for no more than five working days following the failure of 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 individual filter monitoring for at least three years.

a. When a particular water treatment plant is not configured to allow individual filter turbidity monitoring (e.g., Greenleaf Filter Plants) as required under Paragraph 1 of this Subsection, the system shall consult with DHH on a case-by-case basis to obtain approval of a plant specific alternative monitoring plan which is deemed to comply with the intent of individual filter turbidity monitoring, as far as is possible.

2. Triggered Actions Based on Individual Filter Results

a. For a public water system using surface water or GWUDISW and which serves at least 10,000 individuals, refer to §1135. E.1 of this Chapter for additional actions which may be triggered dependent upon the results of individual filter turbidity monitoring. Compliance deadlines for performing such additional actions are also contained in §1135. E.1 of this Chapter.

b. For a public water system using surface water or GWUDISW and which serves less than 10,000 individuals, refer to §1135. F.1 of this Chapter for additional actions which may be triggered dependent upon the results of individual filter turbidity monitoring. Compliance deadlines for performing such additional actions are also contained in §1135. F.1 of this Chapter.

La. Admin. Code tit. 51, § XII-1123

Promulgated by the Department of Health and Hospitals, Office of Public Health, LR 28:1342 (June 2002), amended LR 28:2522 (December 2002), LR 35:1242 (July 2009).

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