La. Admin. Code tit. 51 § XII-263

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

Section XII-263 - Precipitative Softening Sludge

A. Sludge from plants using precipitative softening varies in quantity and in chemical characteristics depending on the softening process and the chemical characteristics of the water being softened. Recent studies show that the quantity of sludge produced is much larger than indicated by stoichiometric calculations. Sludge from plants using precipitative softening shall be treated and disposed of as follows.

1. Lagoons. The use of lagoons shall comply with the following.

a. Short term storage lagoons should be designed on the basis of 0.7 acres per million gallons per day per 100 mg/L of hardness removed based on a usable lagoon depth of 5 feet. This should provide about 2 1/2 years storage. At least 2 but preferably more lagoons shall be provided in order to give flexibility in operation. An acceptable means of final sludge disposal shall be provided. Provisions shall be made for convenient cleaning.

b. Long term lagoons should have a volume of at least four times that for short term storage lagoons.

c. The design of both short term and long term lagoons should provide for:

i. location free from flooding;

ii. when necessary, dikes, deflecting gutters or other means of diverting surface water so that it does not flow into the lagoons;

iii. a minimum usable depth of 5 feet;

iv. adequate freeboard of at least 2 feet;

v. adjustable decanting device;

vi. effluent sampling point;

vii. adequate safety provisions,

viii. parallel operation; and

ix. subsurface infiltration may be acceptable if approved by the appropriate reviewing authority/authorities.

2. The application of liquid lime or dewatered sludge to farm land should be considered as a method of ultimate disposal. Approval from the LDEQ shall be obtained if required.

3. Mixing of lime sludge with activated sludge waste as a means of co-disposal.

4. Disposal at a landfill either as a solid or liquid if the landfill can accept such waste, depending on LDEQ requirements.

5. Mechanical dewatering of sludge may be considered. Pilot studies on a particular plant waste are recommended. Mechanical dewatering should be preceded by sludge concentration and chemical pre-treatment.

6. Calcination of sludge may be considered. Pilot studies on a particular plant waste are recommended.

7. Discharge of lime sludge to sanitary sewers should be avoided since it may cause both liquid volume and sludge volume problems at the sewage treatment plant. This method shall be used only when the sewerage system has the capability to adequately handle the lime sludge.

B. Lime sludge drying beds shall not be used as a method of treating and/or disposing of sludge.

La. Admin. Code tit. 51, § XII-263

Promulgated by the Department of Health, Office of Public Health, LR 44342 (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).