Design recommendations for subsurface flow constructed wetlands for nitrification and denitrification

• Published in: Water Science & Technology Vol. 40; no. 3; pp. 257 - 263
• Main Author: Platzer, Christoph
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 1999; Pergamon Press; IWA Publishing
• Subjects: Aeration; Applied sciences; Artificial wetlands; Biological and medical sciences; Biological treatment of waters; Biotechnology; Carbon-nitrogen ratio; Constructed wetland; Denitrification; Design; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General purification processes; horizontal-flow bed; Industrial applications and implications. Economical aspects; Mathematical analysis; Mathematical models; Nitrification; Nitrogen removal; Oxygen; Oxygen balance; Oxygen demand; Oxygen requirement; Pollution; Removal; Soil; Soil aeration; subsurface flow; vertical-flow bed; Wastewater; Wastewater treatment; Wastewater treatment plants; Wastewaters; Water treatment and pollution; Wetlands; Germany; subsurface flow; horizontal-flow bed; denitrification; Constructed wetland; nitrification; vertical-flow bed; Artificial medium; Nitrification; Denitrification; Waste water purification; Wetland; Subsurface; Biological purification
• ISBN: 9780080434247; 008043424X
• ISSN: 0273-1223; 1996-9732
• DOI: 10.1016/S0273-1223(99)00420-5

The paper presents a design for nitrogen removal in subsurface flow wetlands. The nitrification in the vertical-flow beds (VFBs) is clearly determined by the oxygen balance in the filter. Full nitrification can only be achieved when the oxygen balance is positive. For sizing purposes equations for the calculation of oxygen demand and oxygen input are given. Three possibilities to achieve sufficient soil aeration are presented and explained. For the denitrification two possibilities are presented. From technical wastewater treatment plants pre-denitrification is well known. Return rates up to 200% can be used without hydraulic problems for the VFBs. In cases of low C/N ratios an additional application of HFBs has to be used. The design can be carried out using a design of 1 g NO3−N/m2,d achieving a 65% removal in more than 90% of the cases. The paper discusses some of the equations presented internationally. The suitability of the use of k-values for the processes nitrification and denitrification is especially questioned.