{"id":{"repo_id":"unt","oai_identifier":"info:ark/67531/metadc3183"},"canonical_url":"https://search.dev.ndltd.org/etd/unt/info:ark/67531/metadc3183","repository":{"repo_id":"unt","name":"University of North Texas","base_url":"https://digital.library.unt.edu/oai/"},"display":{"title":"Phosphorus Retention and Fractionation in Masonry Sand and Light Weight Expanded Shale Used as Substrate in a Subsurface Flow Wetland","abstract":"Constructed wetlands are considered an inefficient technology for long-term phosphorus (P) removal. The P retention effectiveness of subsurface wetlands can be improved by using appropriate substrates. The objectives of this study were to: (i) use sorption isotherms to estimate the P sorption capacity of the two materials, masonry sand and light weight expanded shale; (ii) describe dissolved P removal in small (2.7 m3) subsurface flow wetlands; (iii) quantify the forms of P retained by the substrates in the pilot cells; and (iv) use resulting data to assess the technical and economic feasibility of the most promising system to remove P. The P sorption capacity of masonry sand and expanded shale, as determined with Langmuir isotherms, was 60 mg/kg and 971 mg/kg respectively. In the pilot cells receiving secondarily treated wastewater, cells containing expanded shale retained a greater proportion of the incoming P (50.8 percent) than cells containing masonry sand (14.5 percent). After a year of operation, samples were analyzed for total P (TP) and total inorganic P (TIP). Subsamples were fractionated into labile-P, Fe+Al-bound P, humic-P, Ca+Mg-bound P, and residual-P. Means and standard deviations of TP retained by the expanded shale and masonry sand were 349 + 169 and 11.9 + 18.6 mg/kg respectively. The largest forms of P retained by the expanded shale pilot cells were Fe+Al- bound P (108 mg/kg), followed by labile-P (46.7 mg/kg) and humic-P (39.8). Increases in the P forms of masonry sand were greatest in labile-P (7.5 mg/kg). The cost of an expanded shale wetland is within the range of costs conventional technologies for P removal. Accurate cost comparisons are dependent upon expansion capacity of the system under consideration. Materials with a high P sorption capacity also have potential for enhancing P removal in other constructed wetland applications such as stormwater wetlands and wetlands for treating agricultural runoff.","abstract_html":"Constructed wetlands are considered an inefficient technology for long-term phosphorus (P) removal. The P retention effectiveness of subsurface wetlands can be improved by using appropriate substrates. The objectives of this study were to: (i) use sorption isotherms to estimate the P sorption capacity of the two materials, masonry sand and light weight expanded shale; (ii) describe dissolved P removal in small (2.7 m3) subsurface flow wetlands; (iii) quantify the forms of P retained by the substrates in the pilot cells; and (iv) use resulting data to assess the technical and economic feasibility of the most promising system to remove P. The P sorption capacity of masonry sand and expanded shale, as determined with Langmuir isotherms, was 60 mg/kg and 971 mg/kg respectively. In the pilot cells receiving secondarily treated wastewater, cells containing expanded shale retained a greater proportion of the incoming P (50.8 percent) than cells containing masonry sand (14.5 percent). After a year of operation, samples were analyzed for total P (TP) and total inorganic P (TIP). Subsamples were fractionated into labile-P, Fe+Al-bound P, humic-P, Ca+Mg-bound P, and residual-P. Means and standard deviations of TP retained by the expanded shale and masonry sand were 349 + 169 and 11.9 + 18.6 mg/kg respectively. The largest forms of P retained by the expanded shale pilot cells were Fe+Al- bound P (108 mg/kg), followed by labile-P (46.7 mg/kg) and humic-P (39.8). Increases in the P forms of masonry sand were greatest in labile-P (7.5 mg/kg). The cost of an expanded shale wetland is within the range of costs conventional technologies for P removal. Accurate cost comparisons are dependent upon expansion capacity of the system under consideration. Materials with a high P sorption capacity also have potential for enhancing P removal in other constructed wetland applications such as stormwater wetlands and wetlands for treating agricultural runoff.","abstract_has_math":false,"creators":["Forbes, Margaret G."],"institution":"University of North Texas","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Dickson, Kenneth L.","Doyle, Robert D.","Hudak, Paul F.","Saleh, Farida","Waller, William T."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2002,"date_issued":"2002-08","date_published":"2002-08","updated_at":"2026-07-24T05:34:52Z","subjects":["Phosphorus.","Water -- Pollution.","Sewage -- Purification -- Phosphate removal.","Constructed wetlands.","pilot cells","Phosphorus removal","phosphorus fractionation","constructed wetland","wastewater"],"languages":["English"],"rights":["Use restricted to UNT Community","Copyright","Forbes, Margaret G.","Copyright is held by the author, unless otherwise noted. All rights reserved."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oclc: 50677110","untcat: b2426568","https://digital.library.unt.edu/ark:/67531/metadc3183/","ark: ark:/67531/metadc3183"],"render_values":[{"text":"oclc: 50677110","href":null,"code":true},{"text":"untcat: b2426568","href":null,"code":true},{"text":"https://digital.library.unt.edu/ark:/67531/metadc3183/","href":"https://digital.library.unt.edu/ark:/67531/metadc3183/","code":true},{"text":"ark: ark:/67531/metadc3183","href":null,"code":true}]}]},"links":{"outbound_url":"https://doi.org/10.12794/metadc3183","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dickson, Kenneth L.","Doyle, Robert D.","Hudak, Paul F.","Saleh, Farida","Waller, William T."]},{"key":"dc:creator","label":"Author","values":["Forbes, Margaret G."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2002-08"]},{"key":"dc:publisher","label":"Institution","values":["University of North Texas"]},{"key":"dc:type","label":"Dc Type","values":["Thesis or Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Phosphorus.","Water -- Pollution.","Sewage -- Purification -- Phosphate removal.","Constructed wetlands.","pilot cells","Phosphorus removal","phosphorus fractionation","constructed wetland","wastewater"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["Use restricted to UNT Community","Copyright","Forbes, Margaret G.","Copyright is held by the author, unless otherwise noted. 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The objectives of this study were to: (i) use sorption isotherms to estimate the P sorption capacity of the two materials, masonry sand and light weight expanded shale; (ii) describe dissolved P removal in small (2.7 m3) subsurface flow wetlands; (iii) quantify the forms of P retained by the substrates in the pilot cells; and (iv) use resulting data to assess the technical and economic feasibility of the most promising system to remove P. The P sorption capacity of masonry sand and expanded shale, as determined with Langmuir isotherms, was 60 mg/kg and 971 mg/kg respectively. In the pilot cells receiving secondarily treated wastewater, cells containing expanded shale retained a greater proportion of the incoming P (50.8 percent) than cells containing masonry sand (14.5 percent). After a year of operation, samples were analyzed for total P (TP) and total inorganic P (TIP). Subsamples were fractionated into labile-P, Fe+Al-bound P, humic-P, Ca+Mg-bound P, and residual-P. Means and standard deviations of TP retained by the expanded shale and masonry sand were 349 + 169 and 11.9 + 18.6 mg/kg respectively. The largest forms of P retained by the expanded shale pilot cells were Fe+Al- bound P (108 mg/kg), followed by labile-P (46.7 mg/kg) and humic-P (39.8). Increases in the P forms of masonry sand were greatest in labile-P (7.5 mg/kg). The cost of an expanded shale wetland is within the range of costs conventional technologies for P removal. Accurate cost comparisons are dependent upon expansion capacity of the system under consideration. Materials with a high P sorption capacity also have potential for enhancing P removal in other constructed wetland applications such as stormwater wetlands and wetlands for treating agricultural runoff."]},{"key":"dc:format","label":"Dc Format","values":["Text"]},{"key":"dc:title","label":"Title","values":["Phosphorus Retention and Fractionation in Masonry Sand and Light Weight Expanded Shale Used as Substrate in a Subsurface Flow Wetland"]}]}],"canonical_facts":{"dc:contributor":["Dickson, Kenneth L.","Doyle, Robert D.","Hudak, Paul F.","Saleh, Farida","Waller, William T."],"dc:creator":["Forbes, Margaret G."],"dc:date":["2002-08"],"dc:description":["Constructed wetlands are considered an inefficient technology for long-term phosphorus (P) removal. The P retention effectiveness of subsurface wetlands can be improved by using appropriate substrates. The objectives of this study were to: (i) use sorption isotherms to estimate the P sorption capacity of the two materials, masonry sand and light weight expanded shale; (ii) describe dissolved P removal in small (2.7 m3) subsurface flow wetlands; (iii) quantify the forms of P retained by the substrates in the pilot cells; and (iv) use resulting data to assess the technical and economic feasibility of the most promising system to remove P. The P sorption capacity of masonry sand and expanded shale, as determined with Langmuir isotherms, was 60 mg/kg and 971 mg/kg respectively. In the pilot cells receiving secondarily treated wastewater, cells containing expanded shale retained a greater proportion of the incoming P (50.8 percent) than cells containing masonry sand (14.5 percent). After a year of operation, samples were analyzed for total P (TP) and total inorganic P (TIP). Subsamples were fractionated into labile-P, Fe+Al-bound P, humic-P, Ca+Mg-bound P, and residual-P. Means and standard deviations of TP retained by the expanded shale and masonry sand were 349 + 169 and 11.9 + 18.6 mg/kg respectively. The largest forms of P retained by the expanded shale pilot cells were Fe+Al- bound P (108 mg/kg), followed by labile-P (46.7 mg/kg) and humic-P (39.8). Increases in the P forms of masonry sand were greatest in labile-P (7.5 mg/kg). The cost of an expanded shale wetland is within the range of costs conventional technologies for P removal. Accurate cost comparisons are dependent upon expansion capacity of the system under consideration. Materials with a high P sorption capacity also have potential for enhancing P removal in other constructed wetland applications such as stormwater wetlands and wetlands for treating agricultural runoff."],"dc:format":["Text"],"dc:identifier":["oclc: 50677110","untcat: b2426568","doi: 10.12794/metadc3183","https://digital.library.unt.edu/ark:/67531/metadc3183/","ark: ark:/67531/metadc3183"],"dc:language":["English"],"dc:publisher":["University of North Texas"],"dc:rights":["Use restricted to UNT Community","Copyright","Forbes, Margaret G.","Copyright is held by the author, unless otherwise noted. All rights reserved."],"dc:subject":["Phosphorus.","Water -- Pollution.","Sewage -- Purification -- Phosphate removal.","Constructed wetlands.","pilot cells","Phosphorus removal","phosphorus fractionation","constructed wetland","wastewater"],"dc:title":["Phosphorus Retention and Fractionation in Masonry Sand and Light Weight Expanded Shale Used as Substrate in a Subsurface Flow Wetland"],"dc:type":["Thesis or Dissertation"]},"updated_at":"2026-07-24T05:34:52Z"}