940.15 SECONDARY CONTAINMENT REQUIREMENTS.
(a) Exemptions. The following are exempt from secondary containment requirements set forth in this chapter:
(1) Storage of Regulated Substance(s) indoors in an area capable of fully containing within the Facility a total release of the Regulated Substance(s) for which the exemption is being claimed, or draining the release to a wastewater treatment system capable of treating the released substance(s). NOTE: Septic tank systems do not qualify as a wastewater treatment system under this exemption;
(2) Storage of Regulated Substances as consumer products packaged in original containers;
(3) Storage of Regulated Substances in storage units/areas with secondary containment comparable to or exceeding that required in subsections (c) through (e) hereof; and
(4) AST’s located in the 10 year TOT.
(b) Secondary Containment Requirements for AST’s. Unless exempted under subsection (a) hereof, secondary containment is required as follows for AST’s installed after the effective date of this chapter:
(1) All AST’s installed in the one (1) year TOT with a capacity exceeding fifty- five (55) gallons; and
(2) All AST’s installed in the five (5) year TOT with a capacity of five hundred (500) gallons or more when storing petroleum or petroleum-based products, or two hundred and fifty (250) gallons or more when storing all other Regulated Substances.
(c) Construction. Secondary containment systems must be constructed of or lined with materials compatible with the Regulated Substance stored. Secondary containment must be of sufficient thickness, density, and composition so as not to be structurally weakened from contact with the Regulated Substance or precipitation, and must be free of cracks, joints, gaps, or other imperfections which would allow leakage through the containment.
(d) Double Walls and Diking. An AST must have at least one of the following at the choice of the Facility Operator:
(1) Double walls: designed as a containment area and providing the Facility Operator with manual or electronic interstitial space monitoring capabilities. Laminated, coated, or clad materials shall be considered single-walled and shall not be construed to fulfill the requirement for double walling; or
(2) Diking: capable of containing one hundred and ten percent (110%) of the total volume of the tank. If the storage area contains multiple AST’s, the secondary containment must be large enough to contain one hundred and fifty percent (150%) of the volume of the largest AST placed in it, or ten percent (10%) of the aggregate internal volume of all AST’s in the storage area, whichever is greater.
(e) Precipitation.
(1) If an AST using a dike as a secondary containment system is exposed to and subject to accumulation of precipitation within the dike, the dike must be designed and operated as follows:
A. The base of the dike must be sloped to a collection point or sump to allow for controlled removal of accumulated storm water or spilled regulated materials; and
B. If the dike is penetrated by a drainage pipe, the pipe must have a lockable valve. This valve shall be kept closed and locked under normal conditions until a determination is made by the Facility Operator that the discharge of storm water is acceptable pursuant to subsection (e)(2) hereof.
(2) Storm water accumulated within secondary containment that is known or suspected to contain a release from the primary containment unit must be handled in accordance with applicable federal, state, or local laws. No potentially contaminated stormwater may be discharged to a sanitary sewer without approval of the Director of Public Utilities or designee. The Director of Public Utilities or designee may require analysis of the stormwater before allowing discharge to the sanitary sewer if the released substance could present a treatment problem at the wastewater treatment plant. The Facility Operator must take all reasonable steps to neutralize the stormwater before discharging the stormwater to any septic system, dry well, sewer, soil, or surface water body.
(Ord. 98-10-103. Passed 10-14-98.)