Capacitive deionization based water desalination system using an MPPT based solar charge controller

Desalination technologies are expected to play an important role in producing clean water in the future, resulting a surge in the research and development of energy efficient and cost effective technologies for desalination of seawater and brackish water. Membrane-based desalination technologies such as reverse osmosis (RO) are the most commercially used desalination methods for seawater and treatment of agricultural water, but are highly energy intensive and the future development of desalination is dependent on finding more energy efficient technologies. Capacitive deionization (CDI) is an emerging technology for water desalination, and is based on the phenomenon of ion electrosorption. Simple CDI is an energy efficient technology and its applications for desalination of low molar concentration streams, like brackish water, is demonstrated. However, to expand the applications, research is focused on improving the efficiency and salt removal capacity of CDI systems. To this end, the important requirements are finding electrode materials with higher capacities and CDI systems with higher efficiencies. Also, the large-scale application of CDI for personal and industrial applications is dependent on designing CDI systems with potential to be implemented at different capacities and length scales. In this work, we have studied the CDI for removal of salt and nutrients from agricultural water. Various high surface area electrode materials were considered and the efficiency of CDI for removal is measured via downstream analyses on batch experiments and reported, allowing development of preliminary parameters for optimizing CDI systems for high-strength agricultural wastewaters.

The present study analyzes the economic viability of an Integrated Energy System (IES) that couples a Reverse Osmosis (RO) water desalination facility with a Nuclear Power Plant (NPP). The case study is conducted in collaboration with Arizona Public Service (APS), the operating owner of the Palo Verde Generating Station (PVGS) NPP. A challenge APS is facing is that their cooling water acquisition contract with the Sub Regional Operating Group (SROG) will expire soon and a renewal can only be done for a significantly higher price of the water. Therefore, APS is seeking alternative sources for their cooling water. One opportunity is to pump brackish water from the regional ground water. Although much less expensive than the water from the new SROG contract, the salinity of the brackish water is so high that a blend of brackish and SROG water will need additional treatment to improve its quality for use in the PVGS cooling towers. A study has been conducted in 2018 at Idaho National Laboratory (INL) to investigate the economics of an PVGS onsite RO desalination plant that would reduce the salinity of a SROG and brackish water blend to an acceptable level. One of the main findings of that study was that the overall economics of water desalination can be greatly improved if, in addition to cooling water for PVGS, potable water could also be produced and sold for profit. In fact, the study concluded that only producing cooling water for PVGS via RO desalination is not economically viable compared to buying all needed cooling water from the SROG. The present report investigates the economic impact of a large, regional RO desalination plant that could provide potable water for the region, considering the conclusions from last year’s scoping study. The study looks in particular at the water-market situation in the West Valley of Phoenix; i.e., in the area of the municipalities of Buckeye, Goodyear, Avondale and Tolleson. In addition to providing potable water for the adjacent municipalities, the concentrate from the regional RO plant would be taken and treated by PVGS to provide some cooling water for a (hopefully) lower cost than that of the SROG water. Furthermore, a cost structure could be put in place for the treatment of the concentrate from the regional RO that would offset some of the water acquisition cost for APS. The analysis used the Nuclear-Renewable Hybrid Energy System (N-R HES) software framework, which was developed at INL in 2016. The framework has reached some level of maturity, such that it can be applied to more than simple demonstration cases; i.e., real industry problems. The analysis in this report considers two cases (for various scenarios): First, the Base Case is the most economic one for APS, as no RO is built, i.e. the case for which cooling water acquisition and treatment cost are lowest. The 2018 INL study showed that some brackish water can be blended with the effluent SROG water without having to build the onsite RO. The Base Case is where APS pumps the maximum volume of less-expensive brackish water (limited by water chemistry in the cooling towers), blends it with the effluent from the SROG, and no RO is built. Second, the proposed RO Case includes two RO plants, one onsite at PVGS and another larger, regional one close to the brackish water wells. The regional RO produces potable water that is sold to the regional municipalities, while the PVGS RO onsite treats (part of) the regional ROs' concentrate and brackish water blend. The desalinated water from the PVGS RO is used in the cooling towers at PVGS. The analysis evaluates the difference in economics, using the Net Present Value (NPV) and Internal Rate of Return (IRR), between the cases. By comparing the two cases, in addition to evaluating the economics of the regional RO, we can also assess the impact of the regional RO on PVGS and consequently APS economics. The study shows that (for the Base Case) to offset the treatment cost for the RO concentrate, the cost of concentrate treatment to be paid by the regional RO to APS would be between 5 – 35 $/m3 of concentrate (depending on the regional RO size envisaged). Correspondingly, the Levelized Cost of Potable Water (LCOPW), which is the average or unit cost, for the regional RO is in the 0.55 – 0.6 $/m3 range of potable water. Or, considering the residential water demand model developed for the Phoenix West Valley, the NPV of the regional RO would be between $20 and 100 billion.

The existing conventional technologies like Reverse Osmosis, EDI(Electro Deionization), membrane filtration and Ultra Violet filtration offer solutions for drinking water, but various factors like capital and operational cost, ease of operation, maintenance and fouling had been the considerable driving factors to judge the techno-economic paradigm while making a technology selection. Also, the increasing demand for augmenting the safe drinking water calls for novel and sustainable breakthrough technologies. The novel and sustainable technology like Capacitive deionization (CDI) could be a potential alternative which works on electrophoretic phenomenon to provide low TDS (Total Dissolved Solids) drinking water. When water passes between a pair of carbon aerogel electrodes, ionic species are held at the charged electrode surfaces and are removed from the solution during the charging the cycle. After the electrodes become saturated with salts or impurities, the electrodes are regenerated by electrical discharge or polarity reversal, allowing the captured ions to be released into a relatively small purge stream. Thus, CDI can be used to deionize or purify water. An effort is also made to study, evaluate and compare conventional RO technology with Existing CDI technology. Batch ion absorption studies on the newly developed electrodes recorded efficiency with ion removal of 140 ppt using 5 pairs of electrodes (32m 2 area) and the SEM images of the developed electrodes indicated good porosity which in turn illustrates the potential absorption capacity of the developed electrodes. The main factors to be considered while developing an ideal electrode are some of the properties like BET(, electrical conductivity, capacitance, mechanical strength. Correlation studies on the comparison with RO and evaluation of the developed electrodes of the CDI were carried out. I. Introduction The desalination of seawater and brackish groundwater to provide fresh drinking water is an established and thriving industry. Desalinisation refers to any of several processes that removes amount of salt and any other minerals present in the saline water. Salt water is desalinated in order to produce fresh water that is suitable for human consumption or irrigation. The most commonly used technologies at present for the desalination process are Thermal Distillation and Reverse Osmosis (RO) filtration. This report will mainly deal with the research conducted for the development of an ideal electrode which is non-polluting, energy efficient, cost effective and electrically conductive, suitable for an industrial sized capacitive deionisation module. Capacitive Deionisation in other terms can be defined as a powerful desalination module which utilises low-pressure non membrane desalination process. Most of the existing industrial scale desalination centres get their energy from the combustion of fossil fuels, thus in effect exchange potable water for CO2 which causes global warming and eventually contributes to the demise of fresh water. As a result, global warming will lead to increase the need for additional desalination. Therefore, it is imperious to find methods to find desalination of water that are more energy efficient. Thus, electrochemical desalination tools like capacitive deionisation have the potential to be such an energy efficient technology. The main objective of this research is to Evaluate a newly developed electrode for electro adsorption studies and its relevance for CDI technology. Capacitive Deionization technology is evaluated by taking in to consideration factors like construction, operation and maintenance costs to that of reverse osmosis and an head on head evaluation is performed. Taking into consideration brackish type feed water the cost of construction can vary accordingly depending upon various factors. Some of the major factors that influence the design development are:-  Capacity of the water to be treated.  Blending of source water with permeate.  Quality of the feed. (TDS and constituents required removal required)  Concentrate disposal.  Pre and post treatment requirements.

This article deals with the desalination of seawater and brackish water, which can deal with the problem of water scarcity that threatens certain countries in the world; it is now possible to meet the demand for drinking water. Currently, among the various desalination processes, the reverse osmosis technique is the most used. Electrical energy consumption is the most attractive factor in the cost of operating seawater by reverse osmosis in desalination plants. Desalination of water by solar energy can be considered as a very important drinking water alternative. For determining the electrical energy consumption of a single reverse osmosis module, we used the System Advisor Model (SAM) to determine the technical characteristics and costs of a parabolic cylindrical installation and Reverse Osmosis System Analysis (ROSA) to obtain the electrical power of a single reverse osmosis module. The electrical power of a single module is 4101 KW; this is consistent with the manufacturer's data that this power must be between 3900 kW and 4300 KW. Thus, the energy consumption of the system is 4.92 KWh/m3.Thermal power produced by the solar cylindro-parabolic field during the month of May has the maximum that is 208MWth, and the minimum value during the month of April, which equals 6 MWth. Electrical power produced by the plant varied between 47MWe, and 23.8MWe. The maximum energy was generated during the month of July (1900 MWh) with the maximum energy stored (118 MWh).

Desalination of brackish water by nanofiltration and reverse osmosis

Brackish water desalination using reverse osmosis and capacitive deionization at the water-energy nexus

Analysis of desalination alternates for phosphoric acid plant in Tunisia

Can capacitive deionization outperform reverse osmosis for brackish water desalination?

Although the energy efficiency of brackish water capacitive deionization (CDI) and reverse osmosis (RO) have been extensively compared, their relative costs remain poorly defined. We develop a parametric model to estimate the levelized cost of water (LCOW) of three CDI configurations (CDI, membrane CDI, and flow electrode CDI) and compare it with the LCOW of brackish water RO calculated using a process-based optimization model. We find significant deviations between cost-optimal and energy-optimal RO design and operation, highlighting the importance of LCOW in comparative evaluations of desalination technologies. Our results suggest that material (including electrode and ion exchange membrane) costs are the largest cost component for CDI processes. As such, the economic viability of CDI critically depends on the component lifespan, with lifespans longer than 1 year (105 cycles for 5 min cycle duration) required to reduce brackish water desalination costs relative to RO. Finally, sensitivity analyses indicate that CDI processes are unlikely to be cost-competitive against RO for feedwater concentrations greater than 2 g/L. Future research to enhance the economic feasibility of CDI processes should focus on developing more durable electrodes, increasing cost-normalized electrode capacitance, and developing low-cost ion exchange membranes and coatings.

Solar desalination plant for small size use in remote arid areas of South Algeria for the production of drinking water

Performance evaluation of reverse osmosis desalination plant: A case study of Wadi Ma'in, Zara and Mujib Plant

Water desalination is crucial for addressing global water scarcity affecting over 2 billion people. By 2050, water demand could rise by 20-30% due to population growth and urbanization. Currently, over 40% of the global population lacks access to clean water due to overexploitation of conventional sources like rivers and groundwater. This report focuses on experimental analysis of brackish water desalination, primarily using reverse osmosis (RO). Desalination plays a vital role in converting seawater or brackish water into drinkable water, especially in coastal areas. The study explores various desalination methods such as ion exchange, membrane distillation, and vapor compression distillation. Technological advancements, particularly in RO distillation process has enhanced efficiency and sustainability. In this report, pre-treatment processes, including filtration, chemical dosing, antiscalant injection, water softening, are also employed to remove contaminants before desalination. The performance of RO is evaluated based on factors like pressure drop, feed flow rate, and recovery ratio, analyzing water flux, salt rejection rate, energy consumption, and system efficiency. The results provide insights into optimizing brackish water desalination and the discussions are carried out for improvement of the ways such as post treatment, membrane cleaning and advancement in membrane materials for sustainable freshwater production.

A review on capacitive deionization: Recent advances in Prussian blue analogues and carbon materials based electrodes

In the past few years, the commercialization of small scale reverse osmosis (RO) plant for low total dissolved solids (TDS) brackish and contaminated groundwater water desalination offered an alternative solution to obtain drinking water with TDS lower than 500 mg/L. Due to rapid development in membrane technology the technical and economical usefulness of RO process has been improved. In the current research work, a prototype Reverse Osmosis (RO) wastewater treatmentplant has been developed and its performance was evaluated to produce the safe and drinkable water at local small community.Salt rejection and ermeatewater flowrate are the key performance parameters. These performance parameters are influenced by other variable parameters such as applied feed pressure, temperature, recovery and feed water salinity.The RO plant performance has been evaluated through testing different water quality parameters; including physical, chemical and biological analysis of the treated sample. The plant was operated by varying feed water pressures and feed water salinity which indicated that the product water has the highest quality and maximum permeateflow rate at 25 bar of applied feed water pressure for feed water salinity upto 4000 mg/L. The water quality results indicate that permeate obtained after treatment has excellent quality free physical and microbial contaminants.

We are continually inundated with news and views about the demand for water outpacing supply. Our unsustainable development along rivers that do not reach the sea, declining ground water levels, damage to wetlands, high costs associated with acquiring new sources of water, and potential shortages related to global climate change are common news items. In most developed economies, there is little or no unallocated fresh water left to exploit. So, the question becomes: Where do we find “new” water for our burgeoning population? The answer may lie in the treatment of both shallow, brackish ground water and postconsumer water. Recent advances in reverse-osmosis membranes have reduced operational costs and established a linear correlation between total dissolved solids and operational cost of desalination; thus, there is increased interest in brackish water as input source. In the Southwest, the El Paso, Texas, Water Utilities Public Service Board recently dedicated a 100 million L/d desalination plant. Surprisingly, Florida with its high rainfall of more than 100 cm a year and many lakes and rivers is commonly thought of as a water-“rich” state; yet it has more water desalination plants than any other state: the city of Tampa Bay has the largest active desalination plant in the United States and uses brackish water from Tampa Bay. It is estimated that the state of New Mexico contains 16,000 billion m3 (13 billion acre-feet) of shallow brackish ground water (total dissolved solids greater than 500 mg/L and less than sea water, which is 35,000 mg/L). I suspect that development of brackish water aquifers would, in general, have less impact on the ecology than development of fresh water aquifers. That being said, we know little about the extent and chemistry of brackish water aquifers and almost nothing about their boundary conditions. Thus, I propose a federal 10-year sunset assessment of 1‰ per 250 gallons on all the ground water that municipalities extract, or about $1.00 each year for the average household using ground water. It is envisioned that this study would quantify the regional hydrology of these aquifers following the USGS’s Regional Aquifer System-Analysis model for fresh water aquifers. It would also identify any potential deeper formations capable of sequestering desalination concentrate. This small investment coupled with reduced consumption from increased rate changes and conservation measures such as low-flush toilets, low-flow showerheads and watering restrictions will prolong our existing resources and give us time to install the necessary infrastructure. We need to wean ourselves from our “once through, throw it out” philosophy that dominates current water resource management. We also need to reframe the linguistic argument away from “sewerage” or “waste water” toward the more societally acceptable “postconsumer” or “surplus municipal water.” (Remember, it is not a “used” car, it is a “previously owned” car!) Cities will soon no longer have the luxury of passing their used municipal water downstream. “Dilution is the solution to pollution” is a dated and unfair concept of passing water quality problems to the aquatic environment and cleanup expenditures to downstream users. Newly engineered membranes in desalination plants are excellent at removing not only salts but also pharmaceuticals, endocrine disruptors, prions, and other undesirable products left untouched by conventional waste treatment facilities. Combining membrane-treated water with aquifer storage and recovery (ASR) offers some interesting water management possibilities. That is, by recharging refreshed water, which is generally of better quality than native ground water, into aquifers, one can control the blending ratio of refreshed to native ground water in producing well fields. Furthermore, the aquifer provides a unique environment to adjust the temperature and chemistry and continue filtering the recharged water, adding insurance against the transport of many undesirable contaminants. Desalination and ASR are, however, energy-intensive processes; thus, greenhouse gas–free energy is likely to be integrated in any future energy scenario. Currently, approximately 28% of all electrical power generated in the United States is greenhouse gas–free (nuclear 19.3%, hydro 6.5%, biofuels 1.6%, wind less than 1%, and solar less than 1%), so these are likely to be the energy sources for desalination. Because both the membrane and the ASR technologies are mature and well established, development of new water from brackish ground water and postconsumer water could be a rapid and straightforward resolution to many of the domestic and industrial demands of our nation’s water resources well into the future.