Denitrification beds

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Denitrification beds are an environmental technology that can be retrofitted to many waste treatment systems to remove nitrate and reduce the environmental impact of industry and productive sectors.

Denitrification beds are essentially large containers filled with an organic carbon substrate (e.g. wood chip). Wastewater is fed into the bed and a natural microbial denitrification process converts the biologically available nitrate to nitrogen gas. Denitrification beds produce no environmentally detrimental waste products, as “used” carbon substrate can be composted.

The project team combines researchers from GNS Science, Landcare Research and the University of Waikato. Since 2003 we have installed denitrification beds to treat dairy, glasshouse hydroponic and municipal wastewaters. Trials confirm that greater than 99% removal of the nitrate load could be achieved with appropriate bed sizing, design and operation.

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Fundamental research linked to ongoing practical trials is underway to improve design and performance. Current R&D priorities focus on understanding of denitrification bed function, in order to produce a significantly improved bed that achieves complete removal of biologically available nitrate, has a demonstrated and defensible design life, and a footprint less than half that of current designs.

Contact: Stewart Cameron