Fig. 1. Schematic of the Marion, MA septage-treating pond–wetland system (not to scale). Percentages indicate fate of total nitrogen (TN) flowing into the aerated pond system containing floating plants over a 6-mo period (flow-weighted mass balance; Hamersley et al., 2001). Concentrations indicate composition of N species in pond influent and effluent (flow-weighted average during 6 mo).