Environmental and Economic Evaluation of Downflow Hanging Sponge Reactors for Treating High-Strength Organic Wastewater

This study evaluated the performance of a downflow hanging sponge (DHS) in reducing concentrations chemical oxygen demand (COD), ammonia (NH3), total suspended solids (TSS), and dissolved (TDS) high-strength organic wastewater (HSOW). The DHS unit was composed three segments connected vertically operated under different loading rates (OLRs) between 3.01 12.33 kg COD/m3sponge/d at constant hydraulic retention time (HRT) 3.6 h. results demonstrated that system achieved COD, NH3, TSS, TDS removal efficiencies 88.34 ± 6.53%, 64.38 4.37%, 88.13 5.42%, 20.83 1.78% an OLR COD/m3sponge/d, respectively. These significantly (p < 0.05) dropped to 76.39 6.58%, 36.59 2.91%, 80.87 5.71%, 14.20 1.07%, respectively, by increasing COD/m3sponge/d. variation COD experimental data well described first-order (R2 = 0.927) modified Stover–Kincannon models 0.999), providing organics (K1) 27.39 1/d, saturation value (KB) 83.81 g/L/d, maximum utilization rate (Umax) 76.92 g/L/d. Adding another reactor secondary phase improved final effluent quality, complying with most environmental regulation criteria except those related concentrations. Treating HSOW two sequential reactors economically feasible, energy consumption 0.14 kWh/m3 operating cost about 7.07 USD/m3. Accordingly, using dual DHS/DHS units remove nitrogen pollutants from would be promising cost-efficient strategy. However, tertiary treatment could required reduce