title: Alternative filter media for phosphorous removal in a horizontal subsurface flow constructed wetland.
abstract: During the study period from 1997 to 2002 the purification efficiency of phosphorus in the horizontal subsurface flow (HSSF) constructed wetland (CW) in Kodijärve, has been quite high (63-95%). However, slowly increasing trend in outlet P concentrations and decreasing annual P removal rate are obviously the indicators that show possible saturation processes in filter media. To search for potential filter media with high phosphorus sorption capacity, sorption characteristics and particle size distribution of several local sands, gravels, glauconite-sandstone, LWA, and calcareous waste products from oil-shale industry were investigated. The average P sorption capacity for best materials (crashed ash block, oil, shale fly ash and the sediment from oil shale ash plateau) was higher than 96% and estimated design capacity was around 4-5 g P kg(-1). According to results, sediment from oil shale ash plateau was considered as perspective filter media for P retention. In Summer 2002 experimental sedimentation filter, filled with the sediment from oil shale ash plateau, was installed in the outlet from the Kodijärve HSSF CW. According to preliminary results the average P removal in the sedimentation filter was 52%.
authors.affiliation: Institute of Geography, University of Tartu, Tartu, Estonia.
authors.forename: Christina
authors.initials: C
authors.lastname: Vohla
authors.forename: Elar
authors.initials: E
authors.lastname: Põldvere
authors.forename: Alar
authors.initials: A
authors.lastname: Noorvee
authors.forename: Valdo
authors.initials: V
authors.lastname: Kuusemets
authors.forename: Ulo
authors.initials: U
authors.lastname: Mander
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D002244:Carbon; D060729:Coal Ash; D017753:Ecosystem; D005374:Filtration; D019015:Geologic Sediments; D008422:Materials Testing; D008903:Minerals; D052638:Particulate Matter; D010578:Petroleum; D010758:Phosphorus / Q000302:isolation & purification*; D014872:Water Movements; D018508:Water Purification / Q000379:methods*
chemical_list: D060729:Coal Ash; D008903:Minerals; D052638:Particulate Matter; D010578:Petroleum; C554780:glauconite; D010758:Phosphorus; D002244:Carbon