Management of reverse osmosis concentrate by solar distillation (original) (raw)
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Comparative study of brine management technologies for desalination plants
Brine management systems for desalination plants • Technologies for reducing the volume of the generated brines • Technologies for salts recovery form brines • Brine conditioning for other processes a b s t r a c t In recent years, reverse osmosis (RO) has grown as an alternative to traditional potable water sources. A major disadvantage of the RO process is the huge amount of brine and its negative impact as a result of its high salinity. This brine is usually discharged to inland water bodies or to the sea and constitutes a threat to ecosystems and species, such as Posidonia oceanica in the Mediterranean Sea; thus, further research is needed for introducing environmentally friendly and economically viable management options for RO brines. This paper gives an overview of recent research as well as different technologies available at several scales to overcome the environmental problems and evaluate profitability related to discharge of RO concentrates. The treatment options have been classified into four different groups according to their final purpose: 1) technologies for reducing and eliminating brine disposal, 2) technologies for commercial salt recovery, 3) brine adaptation for industrial uses and 4) metal recovery. Solar evaporation, two-stage reverse osmosis, electrodialysis, integrated processes and brine adaptation for the chlor-alkali industry are some of the topics that this paper deals with. In the conclusion section, all of the technologies are compared emphasizing all their advantages and drawbacks, feasibility and development stage in order to provide a decision tool to select the best technology for each situation.
Environmental Science and Pollution Research
A fertilizer drawn forward osmosis (FDFO) process was tested for the concentration of synthetic brine using an industrial-grade fertilizer ammonium sulfate (NH4)2SO4 as the draw solution (DS), NaCl-based synthetic brine as the feed solution (FS), and a commercial forward osmosis (FO) membrane. A bench-scale investigation and a pilot-scale investigation were carried out. By using the highest possible concentration of the DS with a fixed concentration of the FS, the brine generated by reverse osmosis (RO) desalination plants was simulated. The aim of this investigation, performed in batch mode, was to assess the feasibility of using the FDFO process with the tested DS to concentrate the brine by extracting water to dilute the DS. While the main aim of the investigated process was achieving the maximum possible volume reduction of the brine, the resulting DS was further diluted to reduce the nutrients’ concentration in the diluted DS to the acceptable levels producing fertilized water ...
Seawater desalination by reverse osmosis (case study)
Desalination, 2003
This paper presents a case study of the operation and maintenance of 2000 m'/d desalination plant erected in1995. The results have been obtained over 6 years of operation. The plant consists of four units with a capacity 500 m3/d each. The results obtained are used to evaluate and develop the optimum plant operating pressure and temperature. The daily feed salinity, temperature and pressure were recorded, and finally the tota cost for product of potabIe water was calculated. Recommendations were issued regarding the optimum operating conditions and the most pertinent operating problems. A technoeconomical analysis is undertaken in order to evaluate the cost of the water produced and technical reliability of the technology. The objective is to present field results of the reverse osmoses plant operation in order to evaluate the reliability of this technology in comparison with other technologies.
An Overview on the Treatment and Management of the Desalination Brine Solution
Desalination - Challenges and Opportunities, 2020
Due to the increasing limitations of water resources, application of desalination plants is expanding. One of the constraints associated with desalination plant operation is the production of concentrated solution, which is known as brine and can lead to critical challenges in the environment due to its high level of salinity. In this regard, many different disposal options used recently to control and prevent the environmental issues may be caused by the brine. Evaporation ponds, surface water discharge, and deep well injection are considered as the most well-known options to properly dispose concentrated brine. However, the application of these methods is highly restricted by capital cost and their limited uses. The treatment methods vary in terms of their ability in organics removal and can be divided into three different conventional groups as biological, physicochemical, and oxidation. In recent years, more attention has been paid to membrane-based technologies due to their economic performance in recovering precious resources and providing potable water with high recovery rates. This book chapter provides some critical reviews on recent technologies including treatment operations and disposal options to manage concentrated solutions from desalination plants. Finally, electrodialysis, forward osmosis, and membrane distillation as emerging membrane processes are examined in this chapter.
Heat extraction and brine management from salinity gradient solar pond and membrane distillation
Chemical Engineering Research and Design, 2017
The problem associated with the reverse osmosis (RO) system is its brine disposal. Experimental salinity gradient solar pond (SGSP) with surface area 4.65 m 2 was established to extract and apply heat on laboratory scale direct contact membrane distillation (DCMD). In this study, the performance of the SGSP and DCMD system under Pakistan's climatic condition of Islamabad was evaluated. The heat extraction was carried out using internal heat exchanger by passing fresh water through it at different flow rates in summer and winter. Maximum temperature of 37 • C in summer and 28.5 • C in winter was extracted. The extracted heat from SGSP can be used to pre-heat the brine for temperature driven desalination processes. Least drop in lower convective zone (LCZ) temperature of SGSP was observed at flow rate of 7.5 L/min. In DCMD, two temperatures obtained from SGSP (28.5 and 37 • C) at feed side were maintained to investigate the permeate flux, percentage salt rejection and total dissolve solids (TDS). Two further temperatures 50 and 60 • C were maintained to investigate the DCMD performance. Flux increased as temperature difference between feed and permeate increased. 28.5 • C in terms of SGSP temperature was also feasible for DCMD process as flux was maintained over time.
IRJET- Comparison of Desalination by Reverse Osmosis and Solar Powered Methods
IRJET, 2020
Water is the source of life, the basis of human survival, and the principal material base to guarantee the economy substantial development of a country. With increasing global population, the gap between the supply and demand for water is widening and is reaching such alarming levels that in some part of the world, it is posing a threat to human existence. The fresh water scarcity is a growing problem all over the world because only 1% of earth's water is fresh water available for human to drink. The US geological survey found that 96.5% of earth's water is located in seas and oceans and 1.7% of earth's water is located in the ice caps. The remaining percentage is made up of brackish water, slightly salty water found as surface water in estuaries and as groundwater in salty aquifers. The need for fresh water is at the top of the international agenda of critical problems, at least as firmly as climate change. India as a country has 16% of the world's population and 4% of its fresh water resources. In recent years, the increasing threat to water quality is due to human activities has become a matter of great concern. Problems present today are caused by contamination and by over exploitation, or by combination of both, which are faced by many Indian states. This project deals with comparison of conventional method of desalination ie by solar powered desalination and a technological method of desalination by Reverse osmosis. With current technology; it requires great amounts of energy to desalinate ocean water on a scale large enough to meet the needs of a whole city. For this reason, most cities stick with traditional sources of freshwater, such as underground aquifers, rivers, lakes, and runoff from snowpack. Some people, like those in rural Indian villages, use an alternative to burning oil for desalination-solar power. Today, reverse osmosis (RO) membranes are the leading technology for desalination because of their strong separation capabilities and exhibiting a great potential for treatment of waters worldwide. Reverse osmosis (RO) desalination is a treatment process for production of fresh, low salinity potable water from saline water sources via membrane separation. The mineral/salt content of the water is usually measured by the water quality parameter named total dissolved solids (TDS).
Feasibility of salt production from inland RO desalination plant reject brine: A case study
Desalination, 2003
Production and disposal of reject brine are an integral part of an overall desalination process. For inland desalination plants, this poses a serious challenge to operators, as the option of ocean disposal of reject brine is not available. Various disposal options such as reinjection, lined and unlined evaporation ponds and natural depressions (lake) are currently being used. An alternative approach is to further process the reject brine to extract all the salts. This has the advantages of being environmentally friendly and producing commercial products (i.e., salts and fresh water). A desktop pre-feasibility study using data from Petroleum Development Oman (PDO), operating plants in Bahja, Rima, Nimr and Marmul, confirmed the technical feasibility of treating reject brines in simple processing routes using SAL-PROC technology. SAL-PROC is an integrated process for sequential extraction of dissolved elements from inorganic saline waters in the form of valuable chemical products in crystalline, slurry and liquid forms. The process involves multiple evaporation and/or cooling, supplemented by mineral and chemical processing. An analysis indicated that various types of salts including gypsum, sodium chloride, magnesium hydroxide, calcium chloride, calcium carbonate, and sodium sulphate can be produced from the reject brine of PDO desalination plants. These products have an approximate market value of US $895,000 annually.
Water Resources Management, 2009
The main environmental problem related to the desalination of seawater is the brine discharge coming from the processes of desalination of seawater. For coastal desalination plants, the most practical and least expensive brine disposal method is to discharge it into the sea at the plant's outfall. However, there are several harmful environmental effects caused by this direct discharge. This discharged brine (concentrate wastewater) has many properties, which badly affects the environment. It consists of highly concentrated salts and any un-reacted pre-treatment chemicals. It also brings with it heavy metals resulting from the corrosion of tube and flash chamber wall material. Therefore, the largest impact of desalination on the environment occurs at the outfall of the desalination plant. This work addresses the problem of brine or wastewater generated from desalination production process. The work was conducted with the objective of shedding light on the business opportunities associated with brine wastes by using the brine for on-site generation of sodium hypochlorite. Sodium hypochlorite is a useful and valuable chemical product. It is the most widely used active chlorine compound in disinfection. In general, the suggested experimental process was aimed at the dual benefit of on-site generation of sodium hypochlorite and reducing the concentration of the brine. Therefore, the process will not only generate the sodium hypochlorite, but also will protect the environment.
2010
The explosive increase in world population, along with the fast socioeconomic development, have led to an increased water demand, making water shortage one of the greatest problems of modern society. Countries such as Greece, Saudi Arabia and Tunisia face serious water shortage issues and have resorted to solutions such as transporting water by ships from the mainland to islands, a practice that is expensive, energy-intensive and unsustainable. Desalination of seawater is suitable for supplying arid regions with potable water, but extensive brine discharge may affect marine biota. To avoid this impact, we explore the option of directing the desalination effluent to a solar saltworks for brine concentration and salt production, in order to achieve a zero discharge desalination plant. In this context, we conducted a survey in order to evaluate the potential of transferring desalination brine to solar saltworks, so that its disposal to the sea is avoided. Our analysis showed that brine transfer by trucks is prohibitively expensive. In order to make the zero discharge desalination plant economically feasible, efforts should be directed into developing a more efficient technology that will result in the production of only a fraction of the brine that is produced from our systems today.