Effectiveness of Passive Treatment Components for Onsite System Wastewater Renovation

More than 40% of the homes in Georgia use onsite systems to manage household wastewater. Because of water quality concerns as the number on onsite systems increases, advanced wastewater treatment components to reduce biological oxygen demand (BOD), total suspended solids (TSS), and nutrients are more commonly used.. The objective of this study was to evaluate passive, low-maintenance onsite system treatment components. Two complete onsite systems were installed at existing homes bordering or near Lake Sidney Lanier in Hall County, GA. Both systems included a 6,000 l two-compartment septic tank with an effluent filter, two anaerobic upflow filters (AUF), and either a Fe-based or Fe-Al-Ca based P removal system. Wastewater samples were collected monthly for 14 months at multiple locations in the system and were analyzed for pH, dissolved O, BOD, TSS, total N, NH4, NO3, total P, and dissolved reactive P. The septic tank and two AUFs reduced BOD, TSS, and total P by 84, 96, and 58%, respectively. The Fe-based P treatment system further reduced total P and dissolved reactive P concentrations by 63 and 51%, respectively. The Fe-Al-Ca based P treatment system unit was less effective. These results suggest that passive low-cost advanced treatment components can be used to enhance wastewater treatment in onsite systems.