TY - JOUR

T1 - Assessment of clogging in constructed wetlands by saturated hydraulic conductivity measurements

AU - Iovino, Massimo

AU - Alagna, Vincenzo

AU - Aiello, null

AU - Ventura, null

AU - Licciardello, null

AU - Cirelli, null

PY - 2019

Y1 - 2019

N2 - This study aims at defining a methodology to evaluate Ks reductions of gravel material constituting constructed wetland (CW) bed matrices. Several schemes and equations for the Lefranc's test were compared by using different gravel sizes and at multiple spatial scales. The falling-head test method was implemented by using two steel permeameters: one impervious (IMP) and one pervious (P) on one side. At laboratory scale, mean K values for a small size gravel (8-15 × 10-2 m) measured by the IMP and the P permeameters were equal to 19, 466 m/d and 30, 662 m/d, respectively. Mean Ks values for a big size gravel (10-25 × 10-2 m) measured by the IMP and the P permeameters were equal to 12, 135 m/d and 20, 866 m/d, respectively. Comparison of Ks values obtained by the two permeameters at laboratory scale as well as a sensitivity analysis and a calibration, lead to the modification of the standpipe equation, to evaluate also the temporal variation of the horizontal Ks. In particular, both permeameters allow the evaluation of the Ks decreasing after 4 years-operation and 1-1.5 years' operation of the plants at full scale (filled with the small size gravel) and at pilot scale (filled with the big size gravel), respectively.

AB - This study aims at defining a methodology to evaluate Ks reductions of gravel material constituting constructed wetland (CW) bed matrices. Several schemes and equations for the Lefranc's test were compared by using different gravel sizes and at multiple spatial scales. The falling-head test method was implemented by using two steel permeameters: one impervious (IMP) and one pervious (P) on one side. At laboratory scale, mean K values for a small size gravel (8-15 × 10-2 m) measured by the IMP and the P permeameters were equal to 19, 466 m/d and 30, 662 m/d, respectively. Mean Ks values for a big size gravel (10-25 × 10-2 m) measured by the IMP and the P permeameters were equal to 12, 135 m/d and 20, 866 m/d, respectively. Comparison of Ks values obtained by the two permeameters at laboratory scale as well as a sensitivity analysis and a calibration, lead to the modification of the standpipe equation, to evaluate also the temporal variation of the horizontal Ks. In particular, both permeameters allow the evaluation of the Ks decreasing after 4 years-operation and 1-1.5 years' operation of the plants at full scale (filled with the small size gravel) and at pilot scale (filled with the big size gravel), respectively.

KW - Horizontal flow

KW - Ks measurements

KW - Permeameter cell

KW - Horizontal flow

KW - Ks measurements

KW - Permeameter cell

UR - http://hdl.handle.net/10447/367206

UR - https://watermark.silverchair.com/wst079020314.pdf

M3 - Article

SN - 0273-1223

VL - 79

SP - 314

EP - 322

JO - Water Science and Technology

JF - Water Science and Technology

ER -