Nitrate Removal Performance of Denitrifying Woodchip Bioreactors in Tropical Climates

In Australia, declining water quality in the Great Barrier Reef (GBR) is a threat to its marine ecosystems and nitrate (NO3?) from sugar cane-dominated agricultural areas coastal catchments of North Queensland key pollutant concern. Woodchip bioreactors have been identified as potential low-cost remediation technology reduce NO3? runoff cane farms. This study aimed trial different designs (denitrification walls beds) quantify their removal performance distinct tropical climates hydrological regimes that characterize sugarcane farms Queensland. One denitrification wall two beds were installed treat groundwater subsurface tile-drainage wet tropics catchments, where farming relies only on rainfall for crop growth. Two dry assess treating irrigation tailwater sugarcane. All trialled effective at removing NO3?, with exhibiting higher rate (NRR, 2.5 7.1 g N m?3 d?1) compared (0.15 d?1). The NRR depended influent concentration, low concentrations triggered limitation. highest was observed bed tropics, relatively high consistent due use groundwater, elevated irrigation. demonstrates can be useful edge-of-field reducing GBR, when sited designed maximise performance.