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Comparison of phosphorus removal between vertical subsurface flow constructed wetlands with different substrates
Author(s) -
Tang X. Q.,
Huang S. L.,
Scholz M.
Publication year - 2009
Publication title -
water and environment journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 37
eISSN - 1747-6593
pISSN - 1747-6585
DOI - 10.1111/j.1747-6593.2008.00120.x
Subject(s) - phosphorus , ironstone , oil shale , eutrophication , adsorption , hydraulic retention time , environmental chemistry , constructed wetland , environmental engineering , chemistry , environmental science , geology , nutrient , wastewater , geochemistry , paleontology , organic chemistry
Phosphorus removal by constructed wetlands is a key strategy in diffuse pollution control. Phosphorus retention by experimental unplanted vertical‐flow constructed wetlands depends on substrate, influent quality and hydraulic residence time (HRT). The maximal phosphorus adsorption capacities of shale, gravel, ironstone and hornblende were 619.7, 89.05, 324.9 and 153.1 mg/kg, respectively, when the grain size ranged between 0.5 and 1.0 mm. Phosphorus adsorption capacities of shale, ironstone and hornblende were best explained by Langmuir adsorption isotherms. In comparison, Freundlich adsorption isotherms fitted gravel well. In separate column experiments with eutrophic Jin River water, shale showed better soluble reactive phosphorus (SRP) and total phosphorus (TP) retention performances than gravel, ironstone and hornblende. When the HRT was 2.2 days, the mean SRP removal rates were 96.7, 21.1, 33.6 and 33.0% for shale, gravel, ironstone and hornblende, respectively. Findings indicate that both SRP and TP removal rates increased when the HRT was prolonged.