scholarly journals Analysis of the Intake Locations of Salinity Gradient Plants Using Hydrodynamic and Membrane Models

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1133
Author(s):  
Jacobo M. Salamanca ◽  
Oscar Álvarez-Silva ◽  
Aldemar Higgins ◽  
Fernando Tadeo

The gain in net power produced by Salinity Gradient plants in river mouths due to the optimal location of water intakes is analysed in this paper. More precisely, this work focuses on stratified river mouths and the membrane-based technology of Pressure-Retarded Osmosis. A methodology for this analysis is proposed and then applied to a case study in Colombia. Temperature, salinity and water discharge data were gathered at the Magdalena river mouth to develop a hydrodynamic model that represents the salinity profile along the river channel. The net power production of a pressure-retarded osmosis plant is then estimated based on the power produced at membrane level, considering different locations for the saltwater and freshwater intakes. The most adequate locations for the intakes are then deduced by balancing higher power production (due to higher salinity differences between the water intakes) with lower pumping costs (due to shorter pumping distances from the intakes). For the case study analysed, a gain of 14% can be achieved by carefully selecting the water intakes.

Separations ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 64
Author(s):  
Lianfa Song

When hydraulic pressure was added on the feed side of the membrane in the otherwise conventional pressure retarded osmosis (PRO) process, the production rate of the salinity gradient energy could be significantly increased by manipulating the hydraulic pressures on both sides of the membrane. With hydraulic pressure added on the feed side of the membrane, much higher water flux could be obtained than that under the osmotic pressure of the same value. The osmotic pressure of the draw solution, instead of drawing water through the membrane, was mainly reserved to increase the hydraulic pressure of the permeate. In this way, orders of magnitude higher power density than that in the conventional PRO can be obtained with the same salinity gradient. At the optimal conditions, it was demonstrated that the energy production rates that were much higher than the economical breakeven point could be obtained from the pair of seawater and freshwater with the currently available semipermeable membranes.


Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 208 ◽  
Author(s):  
Nazzareno Diodato ◽  
Naziano Filizola ◽  
Pasquale Borrelli ◽  
Panos Panagos ◽  
Gianni Bellocchi

The occurrence of hydrological extremes in the Amazon region and the associated sediment loss during rainfall events are key features in the global climate system. Climate extremes alter the sediment and carbon balance but the ecological consequences of such changes are poorly understood in this region. With the aim of examining the interactions between precipitation and landscape-scale controls of sediment export from the Amazon basin, we developed a parsimonious hydro-climatological model on a multi-year series (1997–2014) of sediment discharge data taken at the outlet of Óbidos (Brazil) watershed (the narrowest and swiftest part of the Amazon River). The calibrated model (correlation coefficient equal to 0.84) captured the sediment load variability of an independent dataset from a different watershed (the Magdalena River basin), and performed better than three alternative approaches. Our model captured the interdecadal variability and the long-term patterns of sediment export. In our reconstruction of yearly sediment discharge over 1859–2014, we observed that landscape erosion changes are mostly induced by single storm events, and result from coupled effects of droughts and storms over long time scales. By quantifying temporal variations in the sediment produced by weathering, this analysis enables a new understanding of the linkage between climate forcing and river response, which drives sediment dynamics in the Amazon basin.


Geology ◽  
2021 ◽  
Author(s):  
C.P. Galeazzi ◽  
R.P. Almeida ◽  
A.H. do Prado

Alluvial rivers are the most important agents of sediment transport in continental basins, whose fluvial deposits enclose information related to the time when rivers were active. In order to extract the most information from fluvial deposits in the sedimentary record, it is imperative to quantify the natural variability of channel patterns at the global scale, explore what controls may influence their development, and investigate whether channel pattern information is preserved in the alluvial plains in order to develop tools for recognizing them in the sedimentary record. By surveying 361 reaches of modern alluvial rivers with available water discharge data at a global scale, we present a quantitative channel pattern classification based on sinuosity and channel count index applicable to the recognition in the rock record. A continuum of channel patterns ranging from high-sinuosity single channel to lowsinuosity multichannels is documented, along with the proportion of depositional elements in their alluvial plains and their conditions of occurrence. Preserved barforms in the alluvial plains of these rivers are used to infer and quantify paleoflow directions at the channel-belt scale and result in ranges of paleocurrent circular variance that may lead to channel pattern identification in the rock record. Data from this work indicate that the recognition of channel patterns may be used to predict paleogeographic features such as the scale of drainage basin area and discharge, slope, and annual discharge regimes.


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