7 Del. Admin. Code § 7103-148.0

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

Section 7103-148.0 - Temporary Sludge Storage Facilities

Temporary sludge storage facilities shall be designed and constructed in accordance with the following specifications:

148.1 Storage facilities shall not be placed in flood prone areas.

148.2 Storage facilities within the 100-year floodplain shall be evaluated as to potential effects on adjoining landowners.

148.3 Storage facilities shall be located on soils of low to moderate permeability or on soils that seal through sedimentation and biological action. If a storage facility is proposed on other soils, the Department shall require permeability tests or use of an impermeable membrane liner or soil sealant, or all of these.

148.4 The minimum design volume of a storage facility which is not completely enclosed shall be the volume of sludge to be stored plus the expected volume of precipitation during the period of storage minus expected evaporation on the pond surface plus the volume of the maximum expected 25 years, 24 hours precipitation event.

148.5 Storage facilities shall be constructed of:

148.5.1 Suitably compacted soils; or

148.5.2 Manufactured materials such as asphalt, steel, reinforced concrete; or

148.5.3 Fiberglass; or

148.5.4 Other materials approved by the Department.

148.6 Storage facilities made by constructing an above ground embankment shall meet the following conditions:

148.6.1 The minimum combined slopes of the embankment shall be five horizontal to one vertical with the wet side not steeper than 2:1 and the dry side not steeper than 3:1.

148.6.2 Embankments having a height of 14 feet or less shall have a minimum top width of 8 feet. Embankments having a height of 15 feet to 19 feet shall have a minimum top width of 10 feet.

148.6.3 The design height of the embankment shall be increased by the amount needed to insure that the design top elevation is maintained after all settlement has taken place. This increase may not be less than 5 percent when compaction rollers are used and not less than 10 percent when bulldozers or scrapers, or both, are used.

148.7 The minimum top elevation of the facility shall be 10 percent above the design depth after settlement. A minimum of one foot of freeboard must be provided in all cases. These provisions may be waived by the Department, or the freeboard requirements reduced if the facility design includes secondary containment capability, and the accumulated liquids are routinely removed from the facility.

148.8 The side slopes of an excavated storage facility may not be steeper than 1:1.

148.9 Storage facilities constructed by both the embankment and excavation method shall meet all of the requirements for above ground embankments of these regulations if the design depth of the sludge impounded against the embankment is 3 feet or more.

148.10 Public access to the storage facility shall be controlled.

148.11 The storage facility shall be located in a relatively level area (usually less than 5 percent slope) and shall be located at least 150 feet from any drainage ditch, swale, or gully, and bermed to prevent run-on or surface water. Areas with slopes greater than 5 percent may be deemed suitable for storage provided that diversion ditches, additional buffer distances, or other provisions can be installed to further control storm water in the areas of the storage facilities.

148.12 The cell floor shall be located at least 2 feet above the maximum seasonal high ground water elevation.

148.13 Adequate specific conditions are included to control odors and potential nuisances.

7 Del. Admin. Code § 7103-148.0