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Showing 4 results for Desalination
Investigation of Indirect Contact Freezing Process in Desalination of Boshehr Beach's Saline Water
M Mahdavi, S Naseri, M Yunesian, A.h Mahvi, M Alimohaadi,
Volume 4, Issue 3 (10-2011)
Abstract

Background and Objectives: Nowadays, most countries of the world have shortage of water due to many reasons such as population growth, rising of living standards, indiscriminate water use, and so on. Besides, in absence of adequate water resources, desalination of brackish and saline waters have been used to supply potable water. Freezing process is one of the methods which can be used to desalinate saline waters.The aim of this study was to survey freezing process to produce potable water from saline water of Persian Gulf shores.
Materials and Methods: This study was conducted in lab-scale by using indirect contact freezing. Three samples of 50 liter were provided from Bushehr shores. The implemented process steps were freezing (crystallization), separation of crystals, surface washing, and thawing. Freezing of the samples (each in 0.5 liter containers) were performed by a refrigerator at -20°C and 0.1KW/h energy consumption.
Results: The removal efficiencies of TDS in the first, second, and third samples by first freezing process were 56, 56, and 51 percent, respectively. Moreover, the removal efficiencies by EC were 42, 44, and 40 percent, respectively. Meanwhile, the removal efficiencies of TDS in first, second, and third samples by second freezing process observed 69, 69, and 68 percent, respectively. Moreover, the removal efficiencies by EC were 61, 60, and 63 percent, respectively. Also, the removal efficiencies of TDS in first, second, and third samples by third freezing process were 72, 73, and 72 percent, respectively. Moreover, the removal efficiencies by EC were 77, 78, and 77 percent, respectively. The production of the potable water by this method was 15-20 percent of the entry water.
Conclusions: According to the obtained results, potable water was obtained after third freezing of the saline water. Meanwhile, TDS of the produced water was less than maximum allowed concentration of Iranian standards.


Performance of microbial desalination cell for wastewater treatment and desalination: continuous operation mode
Mohammad Ali Zazouli, Fathollah Gholami Boroujeni, Ali Asghar Nadi, Azam Ebrahimi,
Volume 15, Issue 1 (4-2022)
Abstract
Background and Objective: With increasing population growth and water pollution, fresh water supply sources are declining and can not meet today's human needs. Thus, energy conversion systems with high efficiency and low pollution such as desalination microbial cell have been considered. Therefore the aim of this research was to investigation the efficiency of microbial desalination cell (MDC) for desalination and treatment of salt wastewater.
Materials and Methods: To address this issue, the decision was taken to use saline synthetic wastewater with different initial salt concentrations (2, 5, 7 and 10 g/L NaCl) and, different hydraulic retention times (1, 2, 3 and 72 h) in open circuit voltage (OCV) and closed circuit voltage (CCV) continuous mode.
Results: The results showed that highest EC removal was 11.2% and 14.3% with 10 g/L NaCl in open and closed circuit mode, respectively. Maximum COD removal of 68.7% was achieved in CCV mode that was obtained at 10 g/L NaCl. Additionally, Escherichia coli, Bacillus, Enterobacter, Staphylococcus aureus, Pseudomonas and Citrobacter were diagnose as effective bacteria in decomposing wastewater.
Conclusion: The obtained results proved that MDC desalination microbial cell technology is Emerging technology that has many unknown aspects; however, it is expected to be an appropriate technique for wastewater treatment and desalination.
 

Impacts of the seawater desalination plants' discharges on survival and ionic balance of Blue swimmer crab, Portunus segnis (Forskal, 1775), in the northern Persian Gulf
Pegah Gheshlaghi, Ehsan Kamrani, Abolfazl Naji, Moslem Daliri,
Volume 15, Issue 2 (8-2022)
Abstract
Background and Objective: Nowadays, the demand for seawater desalination plants (SDPs) has risen worldwide. However, there is a lack of knowledge on the effects of discharging the SDPs brines into the Persian Gulf marine environment and its aquatics health. Therefore, this research was performed to examine the effects of SDPs brines discharged from this facility in the ecosystem of the Persian Gulf on survival and electrolytes in the Blue swimmer crab, Portunus segnis (Forskal,1775) under laboratory conditions.
Materials and Methods: Brines of two types of active SDPs in Hormozgan were collected; then,75 crabs of (P.segnis), with mean (±SD) carapace width of 9.71±2.18 cm and total weight of 61.22±1.04 g, were collected and transported to the laboratory from the Bandar Abbas coast. As a completely randomized design, the samples were tested in 5 treatments (with three repetitions). Mortality was recorded, and at the end of the experimental period (60 days),the level of some electrolytes of the hemolymph (sodium, calcium, magnesium, and potassium) was measured.
Results: Crabs' survival percentage in treatments containing SDPs effluent decreased compared to control (86%), which was more evident in RO 100% and MED 100% treatments with 46.7% and 40%, respectively (p <0.01). The examined electrolyte levels in treatments containing SDPs brine increased compared to control, which were more significant for RO 100% and MED 100% treatments (p <0.01).
Conclusion: This study showed that the SDPs brines would have physiological consequences on aquatic organisms. In nature, the synergy of SDPs effluents with other sources of ecological stress will have severe impacts. Therefore, the necessary regulations and actions should be taken to minimize the environmental effects of SDPs.
 

Effects investigation of seawater concentrate discharge into the sea and discharge modification by modeling: systematic review
Gholamreza Shaghaghi, Amir Hossein Javid, Sara Allahyaribeik, Ali Mashinchian Moradi,
Volume 17, Issue 3 (12-2024)
Abstract 
Background and Objective: The discharge of seawater concentrate from desalination plants into the sea causes irreparable effects on the environment. The purpose of this study is to identify the effects of this discharge, model methods for optimizing it, and design an effective outlet that minimizes environmental impacts and costs. 
Materials and Methods: This study discusses impacts of seawater concentrate discharged into the sea, numerical modeling of diffusion, and outlet design based on discharge standards.A review of articles and sources from databases such as Google Scholar, Academia, Scopus, Civilica and Irandak was conducted using keywords such as “brine discharge”, “numerical modeling”, and “outlet design.” Out of 132 reviewed articles, 45 articles were consistent with the objectives of the study.
Results: The effects of seawater discharge can be observed in the discharge area and at greater distances. Numerical modeling is employed to predict pollutant concentrations at various distances and to determine the optimal discharge point while considering established standards. The design of the diffuser and the use of multiple nozzles at an angle of 60 degrees result in the greatest dilution at the discharge point.
Conclusion: The use of desalination systems necessitates addressing the effects of climate change. Appropriate modeling and design of the outlet are essential for complying with environmental standards and optimizing costs. Further research in this field is needed.

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