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028 <br /> Based on the site limitations for wastewater disposal, CHR Associates <br /> requested the N.C. Department of Human Resources and Orange County Health <br /> Department to conduct on-site soils suitability evaluations for septic <br /> tank treatment. Investigations concluded that individual, on-site septic <br /> systems could not be approved due to generally poor soils suitability. <br /> However, approximately 2.75 acres of land was found to have marginal soils <br /> suitable for subsurface soil absorption. <br /> The following sections present our recommended wastewater treatment plan <br /> and the project approach methodology required to implement the proposed <br /> action. <br /> Wastewater process Recommendation <br /> The only viable alternative for wastewater treatment in this environment- <br /> ally sensitive area is a "cluster" septic tank effluent pumping (STEP) <br /> system concept with treatment by individual septic tank systems with <br /> centralized effluent collection and disposal by low pressure subsurface <br /> irrigation. The exact size of the system is determined by the area of <br /> suitable soil and the soil loading rate established by the Orange County <br /> Health Department. Wastewater collection would be provided by a small <br /> diameter, pressure sewer system. The proposed system would consist of the <br /> following components: <br /> 1) Individual residential septic tank/pump tank system (each lot); <br /> 2) Small diameter pressure sewer located in street right-of-way; <br /> 3) Central effluent processing and irrigation pumping system; and <br /> • <br /> 4) Low pressure pipe, subsurface irrigation system (LP?S). <br /> Although this is not a widely used wastewater treatment concept, nonethe- <br /> less it is in use across the State and is regarded by State regulatory <br /> agencies as an acceptable method of treatment in areas with special soil <br /> or topographic conditions. A more in-depth explanation of the STEP system <br /> . is provided in Exhibit A in the Appendix. <br /> Process Design Parameters <br /> The principal wastewater system design parameter influencing size and <br /> facility location are as follows: <br /> A. Ori in & Flow <br /> • <br /> 1) - Service Area: 14 lots <br /> 2) Source of Waste Load: - <br /> 3) No. of Bedrooms/Residence: - Single family residence <br /> 4) Waste Load Assessment: 3-l/2 2 bedrooms <br /> : 120 gpd/bedroom <br /> 5) Design Flow <br /> - -- - 5,880 gpd <br /> CRAIG B.MORGAN AND ASSOCIATES.P.A.•••••��....1, <br />