In the installation of aerobic digestion systems:
   (a)   The raw sewage flow from the home shall be intercepted by a settling tank prior to its entering an aeration compartment. The settling tank shall have a holding capacity of at least 500 gallons and shall be equipped with an access and inspection manhole so located as to allow for easy inspection and effective cleaning. The invert of the inlet to the tank shall be at least four inches above the liquid level and shall discharge directly into the tank rather than through a tee connection. There shall be no objection to an inlet baffle. The outlet from the septic tank to the aeration tank shall either be baffled or equipped with a tee or long ell equivalent to a four-inch vitrified pipe.
   (b)   The design and installation of aerobic systems shall be such that each unit must be at a set level and at the correct elevation. The sound level of the unit in operation shall be such as not to constitute a nuisance.
   (c)   In addition to inspection manholes, access manholes shall be provided. Access manholes shall have a sufficiently clear opening to allow for replacement of nonmechanical parts or tank cleaning. These access manhole openings may be cast into the top cover or developed with a riser. The minimum earth cover over the tank shall be twelve inches and the maximum earth cover thirty-six inches. This maximum may be exceeded if a standard manhole is provided.
   (d)   The excavation for the sand filter shall be of the size specified in Section 1042.07 and level on the bottom. Two inches of crushed gravel shall be evenly spread over the bottom of the pit, then four inches of vitrified open bell tile shall be laid to pick up the maximum amount of water over the entire bed. Six inches of crushed gravel shall be placed over the vitrified tile, then thirty inches of bird's eye sand. The inlet box shall be connected to at least three four-inch open-joint field tiles, so located as to give even distribution over the entire bed, and shall be covered with another four inches of crushed gravel. The whole shall be covered by red rosin paper before being covered by a maximum of twelve inches of fill.
   (e)   All electrical work and equipment shall comply with the requirements of the National Electrical Code. This equipment shall be protected with appropriate safety devices such as overload cut-out switches or fuses. A buzzer that indicates a breakdown of any electrical component of the system, or a warning light in a conspicuous location, shall be installed.
   (f)   Mechanical components such as motors, pumps, air compressors, etc., shall be of sufficient capacity to provide adequate treatment under all normal ranges of system loading and shall be capable of continuous operation for a minimum period of six months.
   (g)   All mechanical equipment must be installed in a properly vented location protected from flooding and foaming. Vents, air intakes and air hoses shall be protected from snow, ice or water vapor accumulation.
(Ord. 1973-7. Passed 9-24-73; Ord. 1984-22. Passed 12-10-84.)