Artificial kidneys for the soil — solving the problem of salinization of the soil and underground water

Desalination of brackish water by nanofiltration and reverse osmosis

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.

Impact of chemical composition of reject brine from inland desalination plants on soil and groundwater, UAE

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This study was performed to understand the chemical properties of coastal groundwaters of Korea and to evaluate salinization and desalinization using the chemical compositions of groundwaters, ionic ratios and base cation exchange. Salinization and desalinization frequently occurs in coastal and reclaimed regions, respectively. The reclaimed regions are mainly distributed in western coastal areas, but those are hardly distributed in southern coastal area. Thus, in the western coastal areas, the chemical compositions of groundwaters were mainly affected by salinization by seawater encroachment and desalinization by recharge of fresh water. 33 ~ 37% of the total groundwater samples were affected by seawater, and 6 ~ 15% of the total brackish and saline groundwater samples observed desalinization. However, in the southern coastal areas, the chemical compositions of groundwaters were mainly influenced by salinization (approximately 30 ~ 34%). Also, desalinization processes were observed in some southern groundwater samples (approximately 2 ~ 4%). While the desalinization in the western coastal groundwater was mainly observed in reclaimed regions, desalinization in the southern coastal groundwater was not observed in only reclaimed region. This study shows that desalinization can be one of main factors controlling the chemical compositions of groundwaters in the coastal areas including reclaimed regions and base cation exchange is good tool to identify desalinization.

Use of evaporation ponds for brine disposal in desalination plants

Reverse osmosis (RO) has proven to be an efficient technique for desalination of seawater, brackish water, and reclaimed wastewater. However, the performance of RO desalination is sensitive to its design parameters and operating conditions. The purpose of this study was to modeling the removal of total dissolved solids (TDS) and Rejection of different ions are reported from water of city of Bandar Abbas. The main purpose of this work was the prepared drinking water intrusion model. In this study, a design method based on a simulation technique has been developed for optimizing RO desalination systems. The design is made with the use of Hydranautics design software version 2011. In this paper main focus is on the design part with software. The desalinated water obtained from reverse osmosis at a pressure of 1.2 MPa showed rejections of approximately 88.49 % for SO4 2 −, 61.42 % for TDS, 70.34 for Cl- and 50.85 for Na+. It shows that software gives accurate design with least possible error and user friendly so world while accepted. Blended water, produced by mixing groundwater and surface, was proposed to optimize the produce drinking water with a recovery rate of 95 %. Reverse osmosis is an excellent alternative for the supply of water in Bandar Abbas.

Both brackish water desalination and seawater desalination processes are well established and in common use around the globe to create new water supply sources. The farther the location of the source water from the ocean or seashore, the lower the salinity (TDS) of the water and the lower the osmotic pressure that needs to be overcome when desalinated water is produced. This is one of the major reasons that brackish desalination is often considered less costly than seawater desalination. A number of project considerations, however, indicate that seawater desalination can be beneficial and more cost-effective than brackish water desalination. To make a fair comparison, we need to properly compare all major aspects of both types of projects to define the best and most appropriate desalination technology. While brackish water has less feed water TDS, it is more challenging to dispose of the produced concentrate. Also, although brackish water desalination needs less energy to overcome osmotic pressure, it usually requires more energy to draw the water from the well than it takes to pump seawater from the open ocean intake. Another factor is that the temperature of the brackish well water may be lower than the temperature of ocean water, giving seawater desalination an advantage in energy demand. In comparing brackish to seawater desalination, these major aspects should be evaluated: (1) Locations of seawater and brackish water plants, relative to the major consumers of the desalinated water, (2) Transportation (pumping and disposal) costs of the feed water and produced water, (3) Potential colocation of a seawater plant with a large industrial user (e.g., power plant) of the seawater for cooling or other purposes, (4) Produced quality of brackish water and seawater desalination in terms of major minerals and emerging contaminants, (5) Sustainability of the water source: capacity and depth of the brackish water wells, as well as the type of soil. (6) Technical and economic aspects of produced concentrate disposal, (7) Permitting process costs for brackish and seawater desalination, and (8) The economics of both brackish and seawater desalination treatment processes: capital costs, operational and maintenance (O&M) costs, lifetime water cost, and total water cost (TWC). This paper discusses the major evaluation criteria and considerations involved in properly comparing the economic and technical aspects of brackish and seawater desalination to determine the more favorable desalination technology for a given desalination project.

The role of SWRO Barcelona-Llobregat Plant in the water supply system of Barcelona Area

Reuse of brine from inland desalination plants with duckweed, fish and halophytes toward increased food production and improved environmental control

Hybrid system of nanofiltration, reverse osmosis and evaporation to treat the brine of inland desalination plants

Desalination plants are being widely used in the inland areas of many countries to supply water for domestic purposes. When these areas are far from the shorelines of salt-water bodies, the opportunity to dispose of the reject brine (also known as concentrate, reject water, or wastewater) back into these water bodies no longer exists. In such instances, the use of evaporation ponds is very significant, both economically and environmentally. Other alternatives for brine disposal may also be very effective in some instances. Under certain conditions, brine from desalination plants can have useful applications. Potentials for such applications are addressed in this paper along with a critical review of current innovative concepts for the disposal of reject brine from inland desalination plants. This paper will also assess the present status of disposal mechanisms of brine from desalination plants and outline future research areas that could be pursued for effective, economical, and environmentally sound means for brine disposal from such plants.

Desalination and disinfection of inland brackish ground water in a capacitive deionization cell using nanoporous activated carbon cloth electrodes

Effects of irrigation water quality and NPK-fertigation levels on plant growth, yield and tuber size of potatoes in a sandy loam alluvial soil of semi-arid region of Indian Punjab

Cape May County, the southernmost county in New Jersey, is on a natural peninsula that is virtually surrounded by saltwater, including the Atlantic Ocean and Delaware Bay. Nearly all of the county's water supply comes from ground water, half of which comes from the shallow aquifer system. Because of its proximity to saltwater bodies, the county's freshwater supply is very limited. This report describes the results of a conceptual and numerical analysis of the shallow-ground-water resources of the county, with emphasis on the effects of saltwater encroachment on water supply. The conceptual analysis was conducted by investigating the hydrogeologic framework, water use, flow system, and water quality. The shallow aquifer system consists of one unconfined aquifer and two confined aquifers. Recharge to the shallow aquifer system is derived mainly from precipitation. Although water-supply is greatest in the unconfined part of the system, the introduction of contaminants from the land surface has precluded extensive use of this aquifer. Withdrawals from the confined aquifers have increased through time in response to the summer influx of tourists, and the water used is ultimately discharged offshore to the Atlantic Ocean. Extensive cones of depression have resulted in these aquifers. The net freshwater loss from the system has led to saltwater encroachment and chloride contamination of the water withdrawn. Chloride contamination is even more severe in the deep aquifer system. The numerical analysis was conducted by using a quasi-three-dimensional finite-difference model of the ground-water system and the sharp-interface approach. Limitations and assumptions inherent in the model involve data quality, computer code, and model application. The model is calibrated to predevelopment and to current hydrologic conditions. The calibrated model was used to simulate ground-water flow under two water-supply-development alternatives for a 30-year planning period. The alternatives involve only modest increases in withdrawals in combination with desalination of brackish ground water or relocation of wells toward inland areas. Simulation results indicate that projected withdrawals for the two alternatives can be sustained without significant additional saltwater encroachment over the planning period. However, saltwater will affect some wells if the current withdrawal scheme is maintained. Finally, information is provided on the use of ground-water monitoring to detect saltwater encroachment.