7 Del. Admin. Code § 7103-135.0

Current through Register Vol. 28, No. 3, September 1, 2024

Section 7103-135.0 - Vector Attraction Reduction Requirements

135.1 All sludge prepared for land application and for sale or give away in bulk or bag must meet the requirements of this subsection for Vector Attraction Reduction in addition to the requirements in Section 700 and in Subsections 117.0, 86.0 and 87.0.

135.2 Vector Attraction Reduction requirements may be achieved by application of one of the following processes:

135.2.1 The mass of volatile solids in the sewage sludge shall be reduce by a minimum of 38 percent (see calculation procedures in "Environmental Regulations and Technology - Control of Pathogens and Vector Attraction in Sewage Sludge", EPA-625/R-92/013, 1992, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268).

135.2.2 When the 38 percent volatile solids reduction requirement in 135.2.1 cannot be met for an anaerobically digested sewage sludge, vector attraction reduction can be demonstrated by digesting a portion of the previously digested sewage sludge anaerobically in the laboratory in a bench-scale unit for 40 additional days at a temperature between 30 and 37 degrees Celsius. When at the end of the 40 days, the volatile solids in the sewage sludge at the beginning of that period is reduced by less than 17 percent, vector attraction reduction is achieved.

135.2.3 When the 38 percent volatile solids reduction requirement in 135.2.1 cannot be met for an aerobically digested sewage sludge, vector attraction reduction can be demonstrated by digesting a portion of the previously digested sewage sludge that has a percent solids of two percent or less aerobically in the laboratory in a bench-scale unit for 30 additional days at 20 degrees Celsius. When at the end of the 30 days, the volatile solids in the sewage sludge at the beginning of that period is reduced by less than 15 percent, vector attraction reduction is achieved.

135.2.4 The specific oxygen uptake rate (SOUR) for sewage sludge treated in an aerobic process shall be equal to or less than 1.5 milligrams of oxygen per hour per gram of total solids (dry weight basis) at a temperature of 20 degrees Celsius.

135.2.5 Sewage sludge shall be treated in an aerobic process for 14 days or longer. During that time, the temperature of the sewage sludge shall be higher than 40 degrees Celsius and the average temperature of the sewage sludge shall be higher than 45 degrees Celsius.

135.2.6 The pH of sewage sludge shall be raised to 12 or higher by alkaline addition and, without the addition of more alkali shall remain at 12 or higher for two hours and then at 11.5 or higher for an additional 22 hours.

135.2.7 The percent solids of sewage sludge that does not contain unstabilized solids generated in a primary wastewater treatment process shall be equal to or greater than 75 percent based on the moisture content and total solids prior to mixing with other materials.

135.2.8 The percent solids of sewage sludge that contains unstabilized solids generated in a primary wastewater treatment process shall be equal to or greater than 90 percent based on the moisture content and total solids prior to mixing with other materials.

135.2.9 Sewage sludge shall be injected below the surface of the land.

135.2.9.1 No significant amount of the sewage sludge shall be present on the land surface within one hour after the sewage sludge is injected.

135.2.9.2 When the sewage sludge that is injected below the surface of the land is Class A with respect to pathogens, the sewage sludge shall be injected below the land surface within eight hours after being discharged from the pathogen treatment process.

135.2.10 Sewage sludge applied to the land surface disposal site shall be incorporated into the soil within six hours after application to or placement on the land.

135.2.10.1 When sewage sludge that is incorporated into the soil is Class A with respect to pathogens, the sewage sludge shall be applied to or placed on the land within eight hours after being discharged from the pathogen treatment process.

135.2.11 The pH of domestic septage shall be raised to 12 or higher by alkaline addition and, without the addition of more alkali, shall remain at 12 or higher for 30 minutes.

135.3 Vector Attraction Reduction requirements may also be met by employment of any one of the following practices in lieu of a specific Vector Reduction process found in Subsection 88.2.1 through 88.2.10.

135.3.1 One of the vector attraction reduction requirements in Subsection 88.2.1 through 88.2.10 shall be met when bulk sewage sludge is applied to agricultural land, forest, a public contact site, or a reclamation site.

135.3.2 One of the vector attraction reduction requirements in Subsection 88.2.1 through 88.2.10 shall be met when bulk sewage sludge is applied to a lawn or a home garden.

135.3.3 One of the vector attraction reduction requirements in Subsection 88.2.1 through 88.2.10 shall be met when sewage sludge is sold or given away in a bag or other container for application to the land.

135.3.4 One of the vector attraction reduction requirements in Subsection 88.2.9, 88.2.10, or 88.2.11 shall be met when domestic septage is applied to agricultural land, forest, or a reclamation site.

135.4 Monitoring and Reporting.

135.4.1 Any sludge prepared for land application or for sale or give away in bulk or bag must be monitored for vector attraction reduction according to the conditions specified in the processes outlined in Subsection 88.2.1 through 88.2.10 or practices outlined in Subsection 88.3.1 through 88.3.4.

135.4.2 Any person that prepares a sludge for land application or for sale or give away in bulk or bag must report vector attraction reduction monitoring results to the Department on a form provided by the Department. The frequency of reporting must comply with the schedule outlined in Subsection 137.0 of these regulations or as specified in the permit.

7 Del. Admin. Code § 7103-135.0