Enhanced denitrification in Downflow Hanging Sponge reactors for decentralised domestic wastewater treatment.

Enhanced aerobic/anoxic Downflow Hanging Sponge (DHS) bioreactors were assessed for carbon (C) and total nitrogen (TN) removal for decentralised domestic wastewater treatment applications. The initial design included upper aerobic and lower anoxic sponge layers, and effluent recirculation, and achieved >80% COD and >90% NH-N removal. However, effluent TN was higher.