Alternative Septic System Design - Designed and Installed by Harold Kilgore of Gravelator Systems, Inc.  In order to build the house we have to get a permit from the Hall County Board of Health.  Septic  system designs are based on a number of factors including the percolation rate of the soil, number of bedrooms (not bathrooms), site set-back requirements and distance from any wells.  Unfortunately, rural lake living does not allow you to FLUSH AND FORGET!! Site set backs are 10 feet from property lines and 10 feet from any structure and 75 feet from any wells (there is one across  the street).    Two other factors impact the design; when the site was originally subdivided and recorded; and, the type of system chosen.   The results of the percolation tests are level 3 equal to 45 minutes per inch, which is good.  For this rate the absorbtion field must have 100 feet of line per bedroom. For a four bedroom home you would need 200 feet. Because of the date when the lot was recorded a 50% reduction     is possible for a gravity fed system. However, no point in pushing the limit. There is a system called a ATU system that aerates the waste in the primary tank increasing the rate of bacterial breakdown. This system would also allow you to reduce the standard field size by 50%. For these reasons we chose an Eljen GSF Septic Waste Disposal System. Established in 1970, Eljen Corporation created     the world’s first prefabricated drainage system for foundation drainage and erosion control applications. The Eljen GSF Geotextile Sand Filter System is a cost-effective upgrade from other septic technologies. Comprised of a proprietary two-stage Bio-Matt™ pre-treatment process, the GSF Modules apply a better-than-secondary aerobic effluent       to the soil, increasing the soil’s ability to accept the effluent. The result is superior treatment in a smaller soil absorption     area. Primary Treatment Zone • Perforated pipe is centered above the GSF Module to distribute septic effluent over and into corrugations created by the cuspated core of the GSF Module. • Septic effluent is filtered through the Bio-Matt fabric. The GSF Module’s unique design provides increased surface area       for biological treatment that greatly exceeds the Module’s footprint. • Open air channels within the GSF Module support aerobic bacterial growth on the Module's geotextile fabric interface, surpassing the surface area required for traditional absorption systems. • An anti-siltation geotextile fabric covers the top and sides of the GSF Module and protects the Specified Sand and soil      from clogging, while maintaining effluent storage within the Module.   Secondary Treatment Zone • Effluent drips into the Specified Sand layer and supports unsaturated flow into the native soil. This Specified Sand/soil interface maintains soil structure, thereby maximizing the available absorption interface in the native soil. The Specified     Sand supports nitrification of the effluent, which reduces oxygen demand in the soil, thus minimizing soil clogging from anaerobic bacteria. • The Specified Sand layer also protects the soil from compaction and helps maintain cracks and crevices in the soil. This preserves the soil’s natural infiltration capacity, which is especially important in finer textured soils, where these large channels are critical for long-term performance. • Native soil provides final filtration and allows for groundwater recharge.