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Effect of flow velocity on phosphorus uptake by bed sediments
Author(s) -
Cheng Haoke,
Zhu Xiaolian
Publication year - 2021
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/wej.12508
Subject(s) - flume , sediment , phosphorus , flow velocity , flow (mathematics) , geology , soil science , sediment transport , volumetric flow rate , flow conditions , hydrology (agriculture) , chemistry , geotechnical engineering , mechanics , geomorphology , physics , organic chemistry
The transport, transformation and ultimate fate of phosphorus (P) in river systems are significantly influenced by hydrodynamic conditions. To investigate the effect of flow velocity on the P uptake by bed sediments, a series of laboratory experiments are carried out in an incubator shaker and an annular flume. The results showed a much longer equilibrium time and a slower rate of P uptake by bed sediments in the flume than those in batch experiments. The process of P uptake by bed sediments was divided into two stages: (i) in the first 24 h, the amount of P uptake increased with the increasing flow velocity and (ii) after 24 h, flow velocity had no significant effect on P uptake by bed sediments. The amount of P uptake appeared fluctuating over different velocities. The paper presents a linear relationship between the P fraction in the bed sediments and the square root of time lapsed, which indicates that the diffusional process of P from water column to bed sediments is the dominant process in controlling the P uptake by bed sediments. The slope and intercept of the regression line were controlled by the flow velocity. Of the two models used to describe the process of P uptake by bed sediments, the Elovich Equation appeared to be better than the boundary layer model due to its ability to distinguish the different uptake rates at different flow velocities.