7 Del. Admin. Code § 7103-133.0
Current through Register Vol. 28, No. 4, October 1, 2024
Section 7103-133.0 - Class B Sludge - Sewage sludges processed to Significantly Reduce Pathogens (PSRP). (Septage included herein as sewage sludge)133.1 Sludges prepared to meet the Class B requirements of this section must be processed by means of one of the following alternatives:133.1.1 Class B Alternative 1. 133.1.1.1 Seven samples of the sewage sludge shall be collected at the time the sewage sludge is used or disposed.133.1.1.2 The geometric mean of the density of fecal coliform in the samples shall be less than either 2,000,000 Most Probable Number per gram of total solids (dry weight basis) or 2,000,000 Colony Forming Units per gram of total solids (dry weight basis).133.1.2 Class B Alternative 2. 133.1.2.1 Aerobic digestion - Sewage 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.133.1.2.2 Air drying - Sewage sludge is dried on sand beds or on paved or unpaved basins. The sewage sludge dries for a minimum of three months. During two of the three months, the ambient average daily temperature is above zero degrees Celsius.133.1.2.3 Anaerobic digestion - Sewage 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.133.1.2.4 Composting - Using either the within-vessel, static aerated pile or windrow composting methods, the temperature of the sewage 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.133.1.2.5 Lime stabilization - Sufficient lime is added to the sewage sludge to raise the pH of the sewage sludge to 12 after 2 hours of contact.133.1.3 Class B - Alternative 3. Sewage sludge that is used or disposed shall be treated in a process that is equivalent to a Process to Significantly Reduce Pathogens, as determined by the Department. 133.2 Monitoring and Reporting.133.2.1 Sludge processed to significantly reduce pathogens must be monitored in accordance with the requirements described in the alternative used. Additional monitoring may be required by the Department as a condition of the preparer's permit.133.2.2 The preparer must submit a report of process monitoring on a form provided by the Department. The frequency of reporting shall conform with the reporting frequency specified in Section 701 of the regulations or as specified in any permit issued for preparation.7 Del. Admin. Code § 7103-133.0