title: Removal of nitrate and phosphorus from hydroponic wastewater using a hybrid denitrification filter (HDF).
abstract: A laboratory-scale hybrid-denitrification filter (HDF) was designed by combining a plant material digester and a denitrification filter into a single unit for the removal of nitrate and phosphorus from glasshouse hydroponic wastewater. The carbon to nitrate (C:N) ratio for efficient operation of the HDF was calculated to be 1.93:1 and the COD/BOD(5) ratio was 1.2:1. When the HDF was continuously operated with the plant material replaced every 2 days and 100% internal recirculation of the effluent, a high level of nitrate removal (320-5 mg N/L, >95% removal) combined with a low effluent sBOD(5) concentration (<5mg/L) was consistently achieved. Moreover, phosphate concentrations in the effluent were maintained below 7.5 mg P/L (>81% reduction). This study demonstrates the potential to combine a digester and a denitrification filter in a single unit to efficiently remove nitrate and phosphate from hydroponic wastewater in a single unit.
authors.affiliation: National Institute of Water and Atmospheric Research Ltd, Hamilton, New Zealand. j.park@niwa.co.nz
authors.forename: J B K
authors.initials: JB
authors.lastname: Park
authors.forename: R J
authors.initials: RJ
authors.lastname: Craggs
authors.forename: J P S
authors.initials: JP
authors.lastname: Sukias
mesh_terms: D002244:Carbon / Q000302:isolation & purification*; D018527:Hydroponics / Q000379:methods*; D009566:Nitrates / Q000302:isolation & purification*; D009584:Nitrogen / Q000032:analysis; D009930:Organic Chemicals; D010710:Phosphates / Q000302:isolation & purification*; D010758:Phosphorus / Q000032:analysis; D018515:Plant Leaves; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D009566:Nitrates; D009930:Organic Chemicals; D010710:Phosphates; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen