Study of the Relation between Sediment Characteristics and Multiphase Flow to the Presence of Sediment Oxygen Demand (SOD) in Open Channels

Dhimas Dwinandha,Haryo Satriyo Tomo

doi:10.1051/matecconf/201814703004

Dhimas Dwinandha, Haryo Satriyo Tomo

Open Access

https://doi.org/10.1051/matecconf/201814703004

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Abstract

A laboratory study was conducted with the aim to determine the correlation between sediment characteristics and multiphase flow analysis of carrier fluid to the presence of SOD. Six sediment samples were tested on their physical and chemical characteristics along with particle size distribution of sediments to find the indication of oxygen consumption and to classify the soil sediment class. For multiphase flow analysis, there were two transition velocities calculated: the transition between a pseudo-homogenous flow and a heterogeneous flow and the limit deposit velocities at the onset of solid particle bed. The SOD test was done in laboratory-scale by using a 600-mL reactor. According to tests, the amount of organic carbon content (TOC) in the samples were ranging from 34.58 to 81.27%, with the sediments’ textures categorised as silt loam, silty clay loam, and sand. In the channels, heterogeneous flow occurred in two channel segments, while the other segments’ regime was classified as homogeneous flow. The obtained SOD values were varied from 0.2427 to 0.8487 g/m2/day with K3 values obtained ranged from 8.6537 to 12.4028 m-1. Based on all analysis, the organic characteristic of sediment holds a key role in the presence of SOD value.

Highlights

sediment oxygen demand (SOD) is the rate at which dissolved oxygen (DO) is removed from the overlying water column by biochemical processes in the streambed sediments [5]
Rounds and Doyle [8] found that the rate of SOD by 1-4 g/m2/day was still high enough to be an important component in a DO depletion
Further research using a variation of the SOD value will reaffirm the statement

Summary

Introduction

SOD is the rate at which DO is removed from the overlying water column by biochemical processes in the streambed sediments [5]. SOD includes oxygen consumption of biological activity (e.g. by microorganisms in the sediment) and chemical oxidation reactions to certain chemical species, including Fe2+, Mn2+, and S2- [6]. Research on the SOD is not a new in determining water quality. Rounds and Doyle [8] found that the rate of SOD by 1-4 g/m2/day (typical SOD value of sandy sediments with little organic material) was still high enough to be an important component in a DO depletion. Et al [9] found the similar result that a minute amount of biodegradable organic compound in the sandy environment could consume oxygen significantly. The decrease in concentration DO can cause a condition called hypoxia (DO < 2 mg/L) and anoxia (no DO at all) that can affect aquatic ecology and human population due to the loss of resources and water pollution [7]

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Discussion

Conclusion