Influence of hydraulic loading rate on performance and energy-efficient of a pilot-scale down-flow hanging sponge reactor treating domestic wastewater

The hydraulic loading rate (HLR) is a vital factor affecting the biological attached growth processes. Herein, a pilot-scale down-flow hanging sponge reactor (DHS) with a capacity of 0.5 m(3)/d was investigated under different HLRs (5.56 and 11.12 m(3)/m(2).d). The DHS reactor was operated at an organic loading rate of 1.2 kgCOD/m(sponge)(3).d. The results showed that COD removal attained 60.4 +/- 11.4% at HRL of 5.56 m(3)/m(2) d while this removal increased to 78% during the steady stage of operating at HLR of 11.12 m(3)/m(2).d. Total suspended solid (TSS) was moderately removed with the efficiencies of 69.7%-75.6%. High NH4+-N removal of 80% was attained during operation, indicated that the nitrification process was mildly sensitive to change of HLR. This proposed technology brings a beneficial economic in decreasing energy consumption. This study suggested a viable treatment solution of the DHS using natural air ventilation, which favors low-income areas. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study showed that the COD and TSS removal rates of the DHS reactor varied under different hydraulic loading rates, with NH4+-N removal rate reaching 80% and showing mild sensitivity to HLR changes. This proposed technology brings economic benefits by reducing energy consumption and can provide a feasible treatment solution for low-income areas.