Soil osmotic potential and its effect on vapor flow from a pervaporative irrigation membrane
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Pervaporative irrigation is a membrane technology that can be used for desalination and subsurface irrigation simultaneously. To irrigate, the tube-shaped polymer membrane is buried in soil and filled with water. Because of the membrane transport process, water enters the soil in the vapor phase, drawn across the membrane when the relative humidity in the air-filled pores is low. Soils are typically humid environments; however, the presence of hygroscopic compounds such as fertilizers decreases the humidity. For example, at 20°C the humidity in air in equilibrium above a saturated ammonium nitrate solution is 63%. Here, experiments showed that the presence of fertilizers in sand increased the water flux across the membrane by an order of magnitude. An expression for vapor sorption into sand containing different hygroscopic compounds was developed and combined with a model of vapor and liquid flow in soil. The success of the model in simulating experimental results suggests that the proposed mechanism, adsorption of moisture from the vapor phase by hygroscopic compounds, explains the observed increase in the flux from the irrigation system.
Date Issued
2018-07
Date Acceptance
2018-01-01
Citation
Journal of Environmental Engineering, 2018, 144 (7)
ISSN
0733-9372
Publisher
American Society of Civil Engineers
Journal / Book Title
Journal of Environmental Engineering
Volume
144
Issue
7
Copyright Statement
© ASCE. This work is made available under the terms of the Creative Commons Attribution 4.0 International license, http://creativecommons.org/licenses/by/4.0/
License URL
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Grant Number
EPSRC Prize Fellowship 2012/13
Subjects
Science & Technology
Technology
Life Sciences & Biomedicine
Engineering, Environmental
Engineering, Civil
Environmental Sciences
Engineering
Environmental Sciences & Ecology
WATER-RETENTION CURVE
HYDRAULIC CONDUCTIVITY
OVEN-DRYNESS
SATURATION
MODELS
FLUX
EVAPORATION
DESCRIBE
Environmental Engineering
0904 Chemical Engineering
0905 Civil Engineering
0907 Environmental Engineering
Publication Status
Published
Article Number
ARTN 04018048
Date Publish Online
2018-04-30