TO: Ella Carey – Clerk to the Board of Supervisors
FROM: Jack M. Kelsey, PE – County Engineer
DATE: 17 March 2005
SUBJECT: Albemarle First Bank Central System Request
Shadwell Antiquairies, Inc., TMP 79-19
The owner of this property has proposed modifications to the existing sewerage system that will facilitate the owner’s desired use of the building. However, these modifications create a “central system” as defined by the Code which must be reviewed by the County Engineer and authorized by the Board of Supervisors. A brief description of the site improvements, the existing sewerage system, and proposed modifications to that system has been provided in the paragraphs that follow. The descriptions make reference to the attached site plan where the existing system has been highlighted in “yellow” and the proposed modifications have been highlighted in “red”.
The site consists of two existing structures. The smaller (west) building was approved as a Tea Room/Restaurant. Sewerage from this Tea Room/Restaurant is discharged into two existing septic tanks located on the south side of the building and the effluent conveyed to the adjacent private pumping station (see attachment). The existing force main conveys the effluent around the west and north sides of the Tea Room/Restaurant and then to an existing distribution box adjacent to State Route 22. This distribution box divides the flow into the two septic fields that are also adjacent to State Route 22.
The larger (east) building was approved as an Antiques/Retail building. Sewerage from the Antiques/Retail building is discharged to a private grinder pump located off the southeast building corner and then pumped in a northernly direction to an existing distribution box (see attachment). The effluent then flows into the existing septic field located directly east of the Antiques/Retail building.
Sewerage System Modifications
The applicant intends to modify the interior of the Antiques/Retail building to provide a multi-user building. The existing sewerage lateral, grinder pump, force main, and septic tank that currently serve the Antique/Retail building are to be abandoned. New individual sewerage connections will be provided to each user. These sewerage laterals will discharge into a new septic tank that will be located on the west side of the Antiques/Retail building (see attached). The effluent from this tank will then be conveyed to the pump station that serves the Tea Room/Restaurant and pumped to the existing distribution box adjacent to Route 22. This box, which currently splits the Tea Room/Restaurant flow into the two septic fields, will be modified or replaced with a new box that will accommodate a third distribution line. This third line will convey a portion of the total flow to the existing septic field located directly east of the Antiques/Retail building.
In summary, the applicant has not proposed to expand the existing buildings nor expand the existing sewerage facilities. The proposed modifications simply redefine and consolidate the sewerage system, resulting in it being classified as a “central system”.
Sewerage System Safeguards & Maintenance
The “Rural Areas” discussions have recently raised concerns for assuring the maintenance and long term function of sewerage systems involving septic tanks and subsurface disposal fields. In the paragraphs that follow I’ll describe the manner in which the Virginia Department of Health (VDH) regulations address these concerns.
The VDH regulations classify the sewerage system serving the Shadwell Antiquaries site as a “Type II” system, meaning it consists of a septic tank, a subsurface disposal field, and serves a commercial or other establishment [12VAC5-610-250]. The VDH permit process includes approval of the system plans and specifications, issuance of a “construction permit”, inspection of the completed system, and lastly issuance of an “operation permit”. The “operation permit” identifies that the owner is responsible to maintain the system and to repair it if it ceases to operate. Any type of system failure, as defined by the regulations, is considered a violation for which VDH may take enforcement action.
In my earlier description of the sewerage system I explained that it is also a “pump” system. The effluent from the septic tank is piped to another tank where the pump is located. A pair of “float” switches controls when the pump turns on and off based on the level of liquid in the pump tank. A third “float” switch triggers a high water alarm. VDH regulations require this to be an audiovisual alarm that is located within an area where it may be monitored. The regulations also require at least ¼ day storage volume (based on the average daily flow) be provided above the high water alarm level to reduce the risk of system back up and/or release of effluent to the ground surface in the event of pump or electrical power failure.
Septic tanks, installed after 1 July 2000, are required by VDH to provide an “inspection port” to allow the accumulation of solids to be periodically checked without the need to uncover the tanks. As an alternative, an “effluent filter” may be installed on the outlet line from the tank with an at grade access port to allow for periodic inspection and cleaning of the filter. The purpose of the filter is to screen any solids that may pass through the septic tank to a pumping system and/or subsurface disposal field. VDH has not yet established any guidelines on how often “effluent filters” should be inspected and cleaned. However, failure to routinely inspect and clean these filters could result in system failure.
Over time sinking and floating solids accumulate inside of a septic tank. The rate of accumulation is dependent on the amount of non-degradable materials that are generated by the user and enter the system. Examples of non-degradable materials include oil, grease, hair, vegetable matter (cellulose), plastics and other synthetic materials. In time the accumulated solids need to be removed. Unfortunately, VDH does not regulate how frequently septic tanks are inspected and pumped out, but they do recommend that septic tanks be pumped and cleaned every 3 to 5 years. Failure to routinely inspect and pump out a septic tank could result in clogging of the distribution box and subsurface disposal field and cause system failure.
In summary the VDH design criteria provide for some safeguards against system failure and the regulations provide that the owner is responsible for the maintenance and repair of the sewerage system. However, there are no VDH requirements for the frequency of system inspection or the pumping and cleaning of the septic tanks. Should this “central system” request be approved, a new septic tank will be installed to serve the Antiques/Retail building. An “inspection port” will be required on this new tank, in accordance with VDH regulations, to allow the accumulation of solids to be checked. The existing septic tanks serving the Tea Room/Restaurant will not be required by VDH to provide any modifications, such as “inspection ports”.
The applicant has not proposed to expand the existing facilities, but rather to simply redefine and consolidate the sewerage system, resulting in it being classified as a “central system”. The VDH design criteria provide for some safeguards against system failure and maintenance provisions are provided for through the regulations. However, there are shortcomings such as no requirements for the frequency of system inspection or the pumping and cleaning of the septic tanks.
As required by the Code, I have reviewed the proposed modifications as the County Engineer and recommend approval of the application with the following conditions:
1. Virginia Department of Health approval for the construction and the operation of the pump and sewerage system modifications prior to the Zoning Administrator approval of any building permit and/or zoning clearance for the subject property.
2. Virginia Department of Health confirmation that the total sewerage flow to the system will not exceed the capacity of the three septic fields prior to the Zoning Administrator approval of any building permit and/or zoning clearance for the subject property. The three septic fields are currently rated by VDH at 630 gpd, 500 gpd and 500 gpd for a total of 1630 gallons per day.
To address the concern for assurances that this system will be adequately inspected and maintained in the future, the application is also recommended for approval with the following conditions:
3. Virginia Department of Health approval of “inspection ports” installed on the existing septic tanks serving the Tea Room/Restaurant building (per 12VAC5-610-817.B.), prior to the Zoning Administrator approval of any building permit and/or zoning clearance for the subject property
4. Annual inspection of the septic tanks by a septic system maintenance professional, possessing a valid “sewage handling” permit issued by the Virginia Department of Health, for the accumulation of solids and the need for pumping and cleaning. This professional shall submit an inspection report to the County Engineer addressing the amount of accumulated solids found in the tanks; the general condition of the tanks, lines, and pumping system; and recommendations for ongoing maintenance of the system to assure its continued operation.
5. Pumping and cleaning of the septic tanks at least every 5 years or more frequently as determined necessary by the septic system maintenance professional and/or the County Engineer based on the annual inspections noted in condition #4 above. The owner shall provide documentation of the completed maintenance to the County Engineer and Zoning Administrator.
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