Article 3. Construction Requirements
12VAC5-640-470. General construction requirements.
Article 3
Construction Requirements
A. No portion of any system may be covered or used until inspected, corrections made if necessary, and approved, by the department or unless expressly authorized in writing by department. All applicable sections contained in the Sewage Handling and Disposal Regulations, 12VAC5-610, shall be used to establish design and construction criteria not contained in this chapter.
B. Gravity sewer lines and lines between components of the system shall be schedule 40 pipe and shall have a minimum grade of 1.25 inches per 10 feet for three-inch and four-inch sewer lines. Discharge lines after primary or secondary treatment units shall have a minimum grade of six inches per 100 feet. Where minimum grades cannot be maintained, detailed pump specifications shall be shown on the site plan in accordance with Article 4 (12VAC5-610-598 et seq.) of Part IV of the Sewage Handling and Disposal Regulations.
C. The treatment unit and all piping and appurtenances shall be located in conformance with the approved plans. All changes in location shall be approved by the local department prior to the installation of the system.
D. All pumps and appurtenances to the pump shall be installed according to the plans and specifications approved by the department and referenced in the permit.
E. All wiring shall be approved by the local building official and shall be weather tight and permanent in nature (hard wired).
F. The control panel for the system shall be located within 15 feet of the treatment unit and shall be provided with a manual override switch. Each pumping station shall be provided with controls for automatically starting and stopping the pumps based on water level. When float type controls are utilized they shall be placed so as to be unaffected by the flow entering the wet well.
G. All mechanical treatment units shall be provided with an alarm system on a separate electrical circuit from the remainder of the treatment unit. The alarm shall be both audio and visual and shall be located in an inhabited portion of the dwelling. Examples of alarm conditions to be monitored include aerator failure, blower failure, and high water level.
H. Except for the discharge pipe, and step type post aeration if used for post-aeration, no portion of the discharging system may be located in the 100-year flood plain.
I. The design must allow for sampling to confirm the efficacy of the treatment process. Sampling ports shall be identified on the construction documents and shall meet the following minimum requirements:
1. All discharging systems utilizing chlorine as a disinfectant shall be equipped with a four inch or larger sampling port connected to an approved effluent collection box at the chlorine contact chamber after the 30-minute or 60-minute contact time (i.e., the sampling port shall be located at the outlet end of the chamber).
2. A separate sampling port shall be required after the dechlorination unit.
3. The sampling location is to be identified and a port provided if needed for sampling the final effluent prior to the effluent entering the discharge channel.
4. Other sampling ports may be required on a case-by-case basis due to the system design.
J. All discharging systems shall have a clean out port, accessible from the surface of the ground within 10 feet of the influent invert of the treatment unit.
K. Positive ventilation shall be provided at pumping stations when personnel are required to enter the station for routine maintenance.
L. Sand filter liners shall be constructed of clay having a permeability of 10-6 cm/sec. or less, a 28 mil vinyl or PVC plastic liner, concrete, or other material approved by the division. A watertight seal shall be provided where underdrain piping exits the filter.
M. The owner of each discharging system shall post a permanent sign at the point of discharge with the following notice:
This pipe carries treated sewage effluent and is not suitable for human consumption. This system is owned by (FULL NAME OF PERMIT HOLDER) and is maintained by (NAME AND PHONE NUMBER OF LICENSED OPERATOR WITH OVERSIGHT OF THE SYSTEM).
The sign shall be posted within three feet of the discharge pipe, shall be plainly visible to the public, and shall be constructed of durable material. All lettering shall be at least one-inch high and shall be clearly legible. The sign shall have black letters on a white background (or be painted in other contrasting colors) and be plainly visible at a distance of 25 feet to a person with normal vision. Failure to maintain this sign shall be grounds for suspending the owner's operation permit.
Statutory Authority
§§ 32.1-12 and 32.1-164 of the Code of Virginia.
Historical Notes
Derived from VR355-34-400 § 3.9, eff. July 30, 1992; amended, Virginia Register Volume 32, Issue 6, eff. December 16, 2015.
12VAC5-640-480. (Repealed.)
Historical Notes
Derived from VR355-34-400 § 3.10, eff. July 30, 1992; repealed, Virginia Register Volume 32, Issue 6, eff. December 16, 2015.