| A significant portion of Arkansas households rely on septic systems as their primary means of wastewater disposal. Arkansas's design regulations are based on the storage philosophy and loading rate charts used by the State which were developed using a standard pipe-and-gravel trench to calculate storage space during periods of hydrologic stress. However, septic system absorption field products with architectures quite different from traditional pipe-and-gravel systems are being installed and dosed with effluent at the same loading rates as traditional systems. This study was conducted to determine if product architecture would result in effluent transmission (performance) differences. Septic system absorption field products of four differing architectures (chamber, gravel-less pipe, polystyrene aggregate, and pipe-and-gravel systems) were installed in a profile-limited soil, Captina silt loam, and dosed with raw effluent at rates calculated by current regulations. Free water monitoring ports were installed within each product. The depth to free water in the monitoring ports was used to evaluate product performance. Preliminary measurements conducted from January through August 2009, indicated that system performance is not affected by product architecture type; however, statistical differences among individual products were observed during periods of hydrologic stress. All products behaved similarly under dry-soil conditions where the seasonal water table was below 91 cm from the surface. Surfacing of effluent was not observed for any product and indicated that the current loading-rate design method is functioning properly. Future research is needed to determine the long-term acceptance rates for different architecture types. |
