influent and effluent TSS values for the 2-year
period are presented in Fig. 2. Variability in influent TSS data (after
startup) is attributed to the episodic discharges of water treatment
plant residuals from five different groundwater treatment
facilities, as well as collection system maintenance activities. In the
April 2013, a membrane water treatment plant began batch discharging
an additional 175 kg/day of iron and manganese laden
residuals to the sewer; influent iron concentrations up to 164 mg/L
were observed in grab samples. The ABR was effective at damping
the wide variations in influent wastewater TSS and producing
effluent concentrations with less variability as shown in