Treatment of hydroponic wastewater by denitrification filters using plant prunings as the organic carbon source.
This study investigated the feasibility of using pre-treated plant liquors as organic carbon sources for the treatment of hydroponic wastewater containing high nitrate-N (>300 mg N/L). The waste plant material was pre-treated to extract organic carbon-rich liquors. When this plant liquor was used as an organic carbon source in denitrification filters at the organic carbon:nitrogen dose rate of 3C:N, nitrate removal efficiencies were >95% and final effluent nitrate concentrations were consistently <20mg N/L. However, at this dose rate, relatively high concentrations (>140 mg/L) of organic carbon (fBOD5) remained in the final effluents. Therefore, a 'compromise' organic carbon:nitrogen dose rate (2C:N) was trialled, at which nitrate removal efficiencies were maintained at >85%, final effluent nitrate concentrations were consistently below 45 mg N/L, and effluent fBOD5 concentrations were <25mg/L. This study has demonstrated that waste plant material is a suitable carbon source for the removal of nitrate from hydroponic wastewater in a denitrification filter.
Park
J B K
JB
National Institute of Water and Atmospheric Research Ltd, PO Box 11-115, Hamilton, New Zealand. j.park@niwa.co.nz <j.park@niwa.co.nz>
Craggs
R J
RJ
Sukias
J P S
JP
D002244:Carbon / Q000032:analysis; D028462:Cucumis; D018527:Hydroponics / Q000379:methods*; D018551:Solanum lycopersicum; D008670:Metals / Q000032:analysis; D009566:Nitrates / Q000302:isolation & purification*; D009584:Nitrogen / Q000032:analysis; D009930:Organic Chemicals; D018515:Plant Leaves; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
D008670:Metals; D009566:Nitrates; D009930:Organic Chemicals; D002244:Carbon; D009584:Nitrogen