South Carolina Code of Regulations
Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL
Subchapter 61-9 - Water Pollution Control Permits
Subchapter 61-9.504 - STANDARDS FOR THE USE OR DISPOSAL OF INDUSTRIAL SLUDGE
Appendix 61-9.504.B - PATHOGEN TREATMENT PROCESSES

1. Aerobic digestion. Industrial sludge is agitated with air or oxygen to maintain aerobic conditions for a specific mean cell residence time at a specific temperature. Values for the mean cell residence time and temperature shall be between 40 days at 20 degrees Celsius and 60 days at 15 degrees Celsius.

2. Air drying. Industrial sludge is dried on sand beds or on paved or unpaved basins. The industrial sludge dries for a minimum of three months. During two of the three months, the ambient average daily temperature is above zero degrees Celsius.

3. Anaerobic digestion. Industrial sludge is treated in the absence of air for a specific mean cell residence time at a specific temperature. Values for the mean cell residence time and temperature shall be between 15 days at 35 to 55 degrees Celsius and 60 days at 20 degrees Celsius.

4. Composting. Using either the within-vessel, static aerated pile, or windrow composting methods, the temperature of the industrial sludge is raised to 40 degrees Celsius or higher and remains at 40 degrees Celsius or higher for five days. For four hours during the five days, the temperature in the compost pile exceeds 55 degrees Celsius.

5. Lime stabilization. Sufficient lime is added to the industrial sludge to raise the pH of the industrial sludge to 12 after two hours of contact.

6. Industrial sludge. Industrial sludge may meet the PSRP requirement through an alternate procedure to be determined by the Department on a case-by-case basis.

1. Composting. Using either the within-vessel composting method or the static aerated pile composting method, the temperature of the industrial sludge is maintained at 55 degrees Celsius or higher for three days.

Using the windrow composting method, the temperature of the industrial sludge is maintained at 55 degrees or higher for 15 days or longer. During the period when the compost is maintained at 55 degrees or higher, there shall be a minimum of five turnings of the windrow.

2. Heat drying. Industrial sludge is dried by direct or indirect contact with hot gases to reduce the moisture content of the industrial sludge to 10 percent or lower. Either the temperature of the industrial sludge particles exceeds 80 degrees Celsius or the wet bulb temperature of the gas in contact with the industrial sludge as the industrial sludge leaves the dryer exceeds 80 degrees Celsius.

3. Heat treatment. Liquid industrial sludge is heated to a temperature of 180 degrees Celsius or higher for 30 minutes.

4. Thermophilic aerobic digestion. Liquid industrial sludge is agitated with air or oxygen to maintain aerobic conditions and the mean cell residence time of the industrial sludge is 10 days at 55 to 60 degrees Celsius.

5. Beta ray irradiation. Industrial sludge is irradiated with beta rays from an accelerator at dosages of at least 1.0 megarad at room temperature (ca. 20 degrees Celsius).

6. Gamma ray irradiation. Industrial sludge is irradiated with gamma rays from certain isotopes, such as Cobalt 60 and Cesium 137, at room temperature (ca. 20 degrees Celsius).

7. Pasteurization. The temperature of the industrial sludge is maintained at 70 degrees Celsius or higher for 30 minutes or longer.

8. Industrial sludge. Industrial sludges may meet the PFRP requirement through an alternate procedure to be determined by the Department on a case-by-case basis.