title: Influence of loading rate and modes on infiltration of treated wastewater in soil-based constructed wetland.
abstract: Over the last 10 years soil-based constructed wetlands for discharge of treated wastewater (TWW) are commonly presented as a valuable option to provide tertiary treatment. The uncomplete knowledge in soil modifications and a lack of clear design practices laid the foundation of this work. The aim of this study was to determine optimal hydraulic loads and to observe the main critical parameters affecting treating performances and hydraulic loads acceptance. For this purpose, a soil rich in clay and backfill was chosen to perform column infiltration tests with TWW. Two loading rates and two loading modes were compared to study the influence of an intermittent feeding. Inlet and outlet waters were periodically analysed and columns were instrumented with balances, tensiometers, O2and temperature probes. Soil physico-chemical characteristics were also taken into account to better understand the modification of the soil. One of the main expectations of tertiary treatment is to improve phosphate removal. A particular attention was thus given to phosphorus retention. The interest of an intermittent feeding in presence of a soil with high clay content was showed. This study highlighted that an intermittent feeding could make possible the use of a clay-rich soil for water infiltration.
authors.affiliation: a IRSTEA, UR MALY , Villeurbanne Cedex , France.
authors.forename: Sara
authors.initials: S
authors.lastname: Bisone
authors.affiliation: b INSA Lyon, Université de Lyon , DEEP, Villeurbanne Cedex , France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Gautier
authors.affiliation: a IRSTEA, UR MALY , Villeurbanne Cedex , France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Masson
authors.affiliation: a IRSTEA, UR MALY , Villeurbanne Cedex , France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Forquet
mesh_terms: D000538:Aluminum Silicates / Q000032:analysis; D000077215:Clay; D010758:Phosphorus / Q000032:analysis; D012987:Soil / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis; D053833:Wetlands
chemical_list: D000538:Aluminum Silicates; D000077215:Clay; D010758:Phosphorus; D012987:Soil; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Constructed wetland; phosphate retention; swelling clay; wastewater infiltration; wastewater tertiary treatment