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A platform for research: civil engineering, architecture and urbanism
Nitrogen and Chemical Oxygen Demand Removal from Septic Tank Wastewater in Subsurface Flow Constructed Wetlands: Substrate (Cation Exchange Capacity) Effects
The current article focuses on chemical oxygen demand (COD) and nitrogen (ammonium and nitrate) removal performance from synthetic human wastewater as affected by different substrate rocks having a range of porosities and cation exchange capacities (CECs). The aggregates included lava rock, lightweight expanded shale, meta‐basalt (control), and zeolite. The first three had CECs of 1 to 4 mequiv/100 gm, whereas the zeolite CEC was much greater (∼80 mequiv/100 gm). Synthetic wastewater was gravity fed to each constructed wetland system, resulting in a 4‐day retention time. Effluent samples were collected, and COD and nitrogen species concentrations measured regularly during four time periods from November 2008 through June 2009. Chemical oxygen demand and nitrogen removal fractions were not significantly different between the field and laboratory constructed wetland systems when corrected for temperature. Similarly, overall COD and nitrogen removal fractions were practically the same for the aggregate substrates. The important difference between aggregate effects was the zeolite's ammonia removal process, which was primarily by adsorption. The resulting single‐stage nitrogen removal process may be an alternative to nitrification and denitrification that may realize significant cost savings in practice.
Nitrogen and Chemical Oxygen Demand Removal from Septic Tank Wastewater in Subsurface Flow Constructed Wetlands: Substrate (Cation Exchange Capacity) Effects
The current article focuses on chemical oxygen demand (COD) and nitrogen (ammonium and nitrate) removal performance from synthetic human wastewater as affected by different substrate rocks having a range of porosities and cation exchange capacities (CECs). The aggregates included lava rock, lightweight expanded shale, meta‐basalt (control), and zeolite. The first three had CECs of 1 to 4 mequiv/100 gm, whereas the zeolite CEC was much greater (∼80 mequiv/100 gm). Synthetic wastewater was gravity fed to each constructed wetland system, resulting in a 4‐day retention time. Effluent samples were collected, and COD and nitrogen species concentrations measured regularly during four time periods from November 2008 through June 2009. Chemical oxygen demand and nitrogen removal fractions were not significantly different between the field and laboratory constructed wetland systems when corrected for temperature. Similarly, overall COD and nitrogen removal fractions were practically the same for the aggregate substrates. The important difference between aggregate effects was the zeolite's ammonia removal process, which was primarily by adsorption. The resulting single‐stage nitrogen removal process may be an alternative to nitrification and denitrification that may realize significant cost savings in practice.
Nitrogen and Chemical Oxygen Demand Removal from Septic Tank Wastewater in Subsurface Flow Constructed Wetlands: Substrate (Cation Exchange Capacity) Effects
Collison, Robert S. (author) / Grismer, Mark E. (author)
Water Environment Research ; 86 ; 314-323
2014-04-01
10 pages
Article (Journal)
Electronic Resource
English
Removal of nutrients from septic tank effluent with baffle subsurface-flow constructed wetlands
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| British Library Conference Proceedings | 1995