Solar Flash Desalination Under Hydrostatically Sustained Vacuum

Author(s):  
Mohammad Abutayeh ◽  
Yogi Goswami

Creating vacuum conditions above liquids increases their evaporation rates. This phenomenon can be integrated into a practical continuous desalination process by repeatedly flashing seawater in vacuumed chambers to produce water vapor that condenses afterwards producing fresh water. Gravity can be used to balance the hydrostatic pressure inside the flash chambers with the outdoor atmospheric pressure to maintain that vacuum, while low grade solar radiation can be used to add heat to seawater before flashing. The proposed desalination system consists of a saline water tank, a concentrated brine tank, and a fresh water tank placed on ground level plus an evaporator and a condenser located several meters above ground. The evaporator-condenser assembly, or flash chamber, is initially filled with saline water that later drops by gravity creating a vacuum above the water surface in the unit without a vacuum pump. The vacuum is maintained by the internal hydrostatic pressure balanced by the atmospheric pressure. The ground tanks are open to the atmosphere, while the flash chamber is insulated and sealed to retain both heat and vacuum.

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Mohammad Abutayeh ◽  
D. Yogi Goswami

A new desalination scheme has been proposed. The system consists of a saline water tank, a concentrated brine tank, and a fresh water tank placed on ground level plus an evaporator and a condenser located several meters above the ground. The evaporator-condenser assembly, or flash chamber, is initially filled with saline water that later drops by gravity, creating a vacuum above the water surface in the unit without a vacuum pump. The vacuum is maintained by the internal hydrostatic pressure balanced by the atmospheric pressure. The ground tanks are open to the atmosphere, while the flash chamber is insulated and sealed to retain both heat and vacuum. A theoretical simulation of the proposed model was carried out using a detailed model built by employing the fundamental physical and thermodynamic relationships to describe the process and was complimented by reliable empirical correlations to estimate the physical properties of the involved species and the operational parameters of the proposed system. The simulation results show that running the system at higher flash temperatures with a fixed flash chamber size will result in faster vacuum erosion leading to less overall evaporation.


2015 ◽  
Vol 9 (1) ◽  
pp. 90-97 ◽  
Author(s):  
Liu Feng ◽  
Ma Fengshan ◽  
Guo Jie ◽  
Ding Kuo

Water-rock interaction of the groundwater in aquifer system has been analyzed and inferred with hydrochemical and isotopic datum in Laizhou Bay, eastern China. 32 samples of groundwater from three boreholes (96-5#, 96-6#, 112- 1#), couples of seawater, saline water, fresh water, surface water and rainfall are obtained in study area for hydrochemical and isotopic analyses. The origin of groundwater is generally concluded by stable isotope (§18O and §D) and the analytic results of Na+, Ca2+, Mg2+, Cl-, SO2- , HCO3- changing with depth, combined with total dissolved solids (TDS), electrical conductivity (EC), can be apparently proofs for serious water-rock interaction. The conclusion reveals that the origin of 96-5#, 112-1# is most likely saline water different from that the groundwater of 96-6# which is possible originated from fresh water, surface water or mixing of both. Compared the ion content of same borehole at different depth and different boreholes with same depth, the optimal area for building main well and mining area is determined eventually is around 96-5#.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 894
Author(s):  
Emad M. Hafez ◽  
Hany S. Osman ◽  
Usama A. Abd El-Razek ◽  
Mohssen Elbagory ◽  
Alaa El-Dein Omara ◽  
...  

The continuity of traditional planting systems in the last few decades has encountered its most significant challenge in the harsh changes in the global climate, leading to frustration in the plant growth and productivity, especially in the arid and semi-arid regions cultivated with moderate or sensitive crops to abiotic stresses. Faba bean, like most legume crops, is considered a moderately sensitive crop to saline soil and/or saline water. In this connection, a field experiment was conducted during the successive winter seasons 2018/2019 and 2019/2020 in a salt-affected soil to explore the combined effects of plant growth-promoting rhizobacteria (PGPR) and potassium (K) silicate on maintaining the soil quality, performance, and productivity of faba bean plants irrigated with either fresh water or saline water. Our findings indicated that the coupled use of PGPR and K silicate under the saline water irrigation treatment had the capability to reduce the levels of exchangeable sodium percentage (ESP) in the soil and to promote the activity of some soil enzymes (urease and dehydrogenase), which recorded nearly non-significant differences compared with fresh water (control) treatment, leading to reinstating the soil quality. Consequently, under salinity stress, the combined application motivated the faba bean vegetative growth, e.g., root length and nodulation, which reinstated the K+/Na+ ions homeostasis, leading to the lessening or equalizing of the activity level of enzymatic antioxidants (CAT, POD, and SOD) compared with the controls of both saline water and fresh water treatments, respectively. Although the irrigation with saline water significantly increased the osmolytes concentration (free amino acids and proline) in faba bean plants compared with fresh water treatment, application of PGPR or K-silicate notably reduced the osmolyte levels below the control treatment, either under stress or non-stress conditions. On the contrary, the concentrations of soluble assimilates (total soluble proteins and total soluble sugars) recorded pronounced increases under tested treatments, which enriched the plant growth, the nutrients (N, P, and K) uptake and translocation to the sink organs, which lastly improved the yield attributes (number of pods plant−1, number of seeds pod−1, 100-seed weight). It was concluded that the combined application of PGPR and K-silicate is considered a profitable strategy that is able to alleviate the harmful impact of salt stress alongside increasing plant growth and productivity.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Muhammad Fauzul Imron ◽  
Setyo Budi Kurniawan ◽  
Siti Rozaimah Sheikh Abdullah

AbstractLeachate is produced from sanitary landfills containing various pollutants, including heavy metals. This study aimed to determine the resistance of bacteria isolated from non-active sanitary landfill leachate to various heavy metals and the effect of salinity levels on the removal of Hg by the isolated bacterium. Four dominant bacteria from approximately 33 × 1017 colony-forming units per mL identified as Vibrio damsela, Pseudomonas aeruginosa, Pseudomonas stutzeri, and Pseudomonas fluorescens were isolated from non-active sanitary landfill leachate. Heavy metal resistance test was conducted for Hg, Cd, Pb, Mg, Zn, Fe, Mn, and Cu (0–20 mg L− 1). The removal of the most toxic heavy metals by the most resistant bacteria was also determined at different salinity levels, i.e., fresh water (0‰), marginal water (10‰), brackish water (20‰), and saline water (30‰). Results showed that the growth of these bacteria is promoted by Fe, Mn, and Cu, but inhibited by Hg, Cd, Pb, Mg, and Zn. The minimum inhibitory concentration (MIC) of all the bacteria in Fe, Mn, and Cu was > 20 mg L− 1. The MIC of V. damsela was 5 mg L− 1 for Hg and >  20 mg L− 1 for Cd, Pb, Mg, and Zn. For P. aeruginosa, MIC was > 20 mg L− 1 for Cd, Pb, Mg, and Zn and 10 mg L− 1 for Hg. Meanwhile, the MIC of P. stutzeri was > 20 mg L− 1 for Pb, Mg, and Zn and 5 mg L− 1 for Hg and Cd. The MIC of P. fluorescens for Hg, Pb, Mg, and Zn was 5, 5, 15, and 20 mg L− 1, respectively, and that for Cd was > 20 mg L− 1. From the MIC results, Hg is the most toxic heavy metal. In marginal water (10‰), P. aeruginosa FZ-2 removed up to 99.7% Hg compared with that in fresh water (0‰), where it removed only 54% for 72 h. Hence, P. aeruginosa FZ-2 is the most resistant to heavy metals, and saline condition exerts a positive effect on bacteria in removing Hg.


1996 ◽  
Vol 180 (1) ◽  
pp. 87-95 ◽  
Author(s):  
S. E. Benes ◽  
R. Arag��s ◽  
R. B. Austin ◽  
S. R. Grattan
Keyword(s):  

1999 ◽  
Author(s):  
Yunus Çerçi ◽  
Yunus A. Çengel ◽  
Byard Wood

Abstract A general relation is obtained for the minimum work input requirement for desalination processes using the second-law of thermodynamics. The relation developed can be used to determine the minimum work input for any salinity of the incoming water, and the recovery ratio. It is also shown that there is a lower and an upper limit for the minimum work, corresponding to recovery ratios of 0% and 100%, respectively. The minimum work input per unit mass of fresh water produced is determined for various salinities of incoming water, and the salinities of fresh water produced, and the results are tabulated and plotted. It is shown that the minimum work is a strong function of salinity, and increases with salinity and the recovery ratio. It is also shown that the minimum work input requirement remains fairly constant for recovery ratios of up to about 80%; the minimum work increases drastically at high recovery ratios; and an optimum value of recovery ratio exists to minimize the power consumption of actual desalination plants. But the value of this optimum recovery ratio decreases with increasing salinity of the incoming saline water. The results presented in this paper can be used as a basis to evaluate the performance of actual desalination plants.


Author(s):  
Fen Du ◽  
Bo Zhang ◽  
Chao Zhu ◽  
Zhiming Ji ◽  
Chao-Hsin Lin

This study develops a control system to automate the operation of a condensation-induced depressurization technology, which is used to achieve sub-atmospheric pressure in an open-flow system on ground. The continuous depressurization is maintained via an integrated series of chambers inside which vacuum is regenerated by condensing and refilling of saturated steam. The low pressure generated inside the chambers is then used to alternatively extract the air out of a flow system for maintaining its sub-atmospheric pressure. The thermodynamic cycle in such a vacuum chamber consists of three sub-processes: air purging to ambient by steam refilling, depressurization by steam condensation, and air-extraction from a flow application. As one chamber undergoing these consecutive processes, another chamber operates in a coordinated different phase to seamlessly maintain a continuous air-extraction operation. This new system provides a quiet and efficient way of using low-grade energy to generate hypobaric environment for needed applications. A cascade arrangement of a proposed multiple-chamber operation is also illustrated. A control system is designed and implemented to realize the automatic and coordinated operation in a dual-chamber, laboratory-scaled system. Exemplified results on process characteristics such as chamber depressurization and air purging are also provided.


2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Ogalo Baka Oluoch ◽  
Esther Mwende Muindi ◽  
Elisha Otieno Gogo

Salinity is a major biotic factor that negatively affects growth and yield of crops. Over 90% of the coastal region of Kenya is arid and semi-arid, most farmers in the region use borehole irrigation water which is saline. Amaranthus spp. is one of the main vegetables grown in coastal region. There is limited information regarding the effect of salinity on amaranthus production. The study sought to determine the effect of saline irrigation water on amaranthus growth in coastal Kenya. Two experiments were set up, one at Mivumoni Secondary School farm in Kwale County and another at Pwani University farm in Kilifi County from beginning of September 2019 to the end of January, 2020. The experiments were laid out in a randomized complete block design and replicated three times. The six treatments tested were: fresh water alone, 75% saline water alone, 100% saline water alone, fresh water + DAP, 75% saline water + DAP, 100% saline water + DAP. Crop growth data collected were: emergence rate, plant height, leaf number, leaf area, chlorophyll content, stem thickness, root density, root weight, root volume and total plant biomass. Data obtained were subjected to analysis of variance using SAS statistical package (SAS, Version 10) and treatment effects were tested for significance using F-test. Significant means at F-test was ranked using Tukey’s test at 5% level of significance. Amaranthus seeds sown in fresh water had higher emergence rate compared to seeds sown in saline water. Salinity regardless of concentration used and application of DAP, resulted in decrease in height, leaf number, leaf area, stem tickness, chlorophyll content, root length, root weight, root volume and total biomass. The study demonstrates that saline irrigation water in coastal Kenya has a negative effect on Amaranthus growth.


2014 ◽  
Vol 57 (3) ◽  
Author(s):  
Paolo Madonia ◽  
Paolo Romano ◽  
Salvatore Inguaggiato

<p>Investigations on correlation drops between near-ground atmospheric pressures measured at sea level and at higher altitudes on Italian volcanoes have been carried out. We looked for perturbations of the atmospheric pressure field driven by volcanic activity, but not excluding possible external triggers for the observed anomalies. Decorrelations between atmospheric pressures measured at Stromboli Island in stations located at different altitudes (years 2002-10) have been analysed and compared with data from other volcanic (Vesuvius) and non volcanic (Mt. Soro) orographic structures. We investigated as their possible triggers volcanic, meteorological and space weather parameters, with particular attention to Total Solar Irradiance (TSI), Kp index and Forbush decreases. Pressure decorrelations seems to be driven by astronomic cycles, with maxima in summer and minima in winter. A further contribution was found, seemingly assignable to TSI anomalies, with correlation minima occurring 12 hours after these but only during phases of high Sun activity. Moreover, during the same phases a main periodicity of about 27 days in pressure decorrelations was revealed by FFT analysis. This period is the same of the Sun Carrington rotation, expressing the periodic reappearance of sunspot groups on Sun’s surface. The strong similarity between recurrences of sunspot number and atmospheric pressure anomalies further supports the role of the former as a possible trigger for the latter.</p>


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