Water Desalination & RO
Desalination, With A Grain Of Salt
DESALINATION WITH A GRAIN OF SALT (2)
Credit to: http://www.pacinst.org
Heather Cooley, Peter H. Gleick, and Gary Wolff
JUNE 2006
Introduction:
THE OCEANS CONTAIN 97% of the Earth’s water. This water is too salty for humans to use for irrigation, drinking, and most commercial and industrial purposes. Because of growing concerns about water scarcity and quality, and disputes over allocations of scarce water resources, a tremendous amount of effort has been devoted to developing technologies to desalinate the vast quantities of seawater available. While substantial progress has been made in recent years, desalination remains a minor source of water in all but the wealthiest, most water-scarce regions. In particular, desalination remains too expensive to be a primary source of fresh water and presents significant social, environmental, and technological obstacles that must be overcome. Nevertheless, in some regions, water planners are looking to desalination as a way to overcome natural limitations on freshwater availability, quality, and reliability. This report provides a comprehensive overview of the benefits and risks of desalination and the barriers that hinder more widespread use of this
technology. It does not address whether desalination is needed in California, nor does it comprehensively compare this supply option with other options, such as conservation, conjunctive use, or water recycling. Previous work at the Pacific Institute suggests that water continues to be used wastefully in California and that substantial amounts of water can be conserved cost-effectively compared to almost all proposed supply expansions, including desalination
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Cleaning Procedures for Composite Polyamide RO Membrane Elements
Note: The Composite Polyamide type of RO membrane elements may not be
exposed to chlorinated water under any circumstances. Any such exposure may
cause irreparable damage to the membrane. Absolute care must be taken
following any disinfection of piping or equipment or the preparation of cleaning or
storage solutions to ensure that no trace of chlorine is present in the feedwater to
the RO membrane elements. If there is any doubt about the presence of chlorine,
perform chemical testing. Neutralize any chlorine residual with a sodium bisulfite
solution, and ensure adequate mixing and contact time to accomplish complete
dechlorination. Dosing rate is 1.8 to 3.0 ppm sodium bisulfite per 1.0 ppm of free
chlorine
Cleaning Procedures for Composite Polyamide RO Membrane Elements
Note: The Composite Polyamide type of RO membrane elements may not be
exposed to chlorinated water under any circumstances. Any such exposure may
cause irreparable damage to the membrane. Absolute care must be taken
following any disinfection of piping or equipment or the preparation of cleaning or
storage solutions to ensure that no trace of chlorine is present in the feedwater to
the RO membrane elements. If there is any doubt about the presence of chlorine,
perform chemical testing. Neutralize any chlorine residual with a sodium bisulfite
solution, and ensure adequate mixing and contact time to accomplish complete
dechlorination. Dosing rate is 1.8 to 3.0 ppm sodium bisulfite per 1.0 ppm of free
chlorine
Desalination: A National Perspective
NOTICE:
The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the panel responsible for the report were chosen for their special competences and with regard for appropriate balance.
Support for this study was provided by the U.S. Bureau of Reclamation under Grant No. 06CS811198. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided
support for the project.
Desalination: A National Perspective
NOTICE:
The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the panel responsible for the report were chosen for their special competences and with regard for appropriate balance.
Support for this study was provided by the U.S. Bureau of Reclamation under Grant No. 06CS811198. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided
support for the project.
Basics of Reverse Osmosis
What is Reverse Osmosis?
Reverse Osmosis is a technology that is used to remove a large majority of contaminants from water by
pushing the water under pressure through a semi permeable membrane. This paper is aimed towards an audience that has little of no experience with Reverse Osmosis and will attempt to explain the basics
in simple terms that should leave the reader with a better overall understanding of Reverse Osmosis technology and its applications.
Basics of Reverse Osmosis
What is Reverse Osmosis?
Reverse Osmosis is a technology that is used to remove a large majority of contaminants from water by
pushing the water under pressure through a semi permeable membrane. This paper is aimed towards an audience that has little of no experience with Reverse Osmosis and will attempt to explain the basics
in simple terms that should leave the reader with a better overall understanding of Reverse Osmosis technology and its applications.
Desalination At A Glance
Introduction:
By desalination, we will be referring to the production of a useful product water from a feed
water that is too high in inorganic materials (salts) to be useful. The feed water may be
seawater, brackish water, or other “impaired” water that cannot be used directly for potable
or general industrial purposes. Notice that this definition includes the treatment of certain
wastewaters for subsequent reuse.
The principal technologies used in desalination are based on concepts that are fairly easy to
grasp by those with a modest amount of scientific training and/or technical experience. In
practice, however, choices of technology and plant design are usually determined by factors
that might appear minor to the inexperienced. Similarly, new technologies that show great
promise in the laboratory frequently fail for reasons that were earlier overlooked or dismissed
as trivial. Indeed, professional fascination with specific technical elegance has, in some
cases, led researchers to remain oblivious to inherent limitations of a process. Nonetheless,
attention to detail over the past five decades has resulted in dramatic reductions in capital
and operating costs as well as greatly increased plant reliability and performance
Desalination At A Glance
Introduction:
By desalination, we will be referring to the production of a useful product water from a feed
water that is too high in inorganic materials (salts) to be useful. The feed water may be
seawater, brackish water, or other “impaired” water that cannot be used directly for potable
or general industrial purposes. Notice that this definition includes the treatment of certain
wastewaters for subsequent reuse.
The principal technologies used in desalination are based on concepts that are fairly easy to
grasp by those with a modest amount of scientific training and/or technical experience. In
practice, however, choices of technology and plant design are usually determined by factors
that might appear minor to the inexperienced. Similarly, new technologies that show great
promise in the laboratory frequently fail for reasons that were earlier overlooked or dismissed
as trivial. Indeed, professional fascination with specific technical elegance has, in some
cases, led researchers to remain oblivious to inherent limitations of a process. Nonetheless,
attention to detail over the past five decades has resulted in dramatic reductions in capital
and operating costs as well as greatly increased plant reliability and performance
Desalination & Water Purification Technologies
Introduction:
The world’s water consumption rate is doubling every 20 years, outpacing by two times the rate of population growth. The availability of good quality water is on the decline and water demand is on the rise. Worldwide availability of fresh water for industrial needs and human consumption is limited.
Various industrial and developmental activities in recent times have resulted in increasing the pollution level and deteriorating the water quality. Water shortages and unreliable water quality are considered major obstacles to achieve sustainable development and improvement in the quality of life. The water
demand in the country is increasing fast due to progressive increase in the demand of water for irrigation, rapid industrialization, and population growth and improving life standards. The existing water resources are diminishing (i) due to unequal distribution of rain water and occasional drought, (ii) excessive exploitation of ground water sources and its insufficient recharge, (iii) deterioration of water quality due to the discharge of domestic and industrial effluents without adequate treatment. This is resulting into water stress/ scarcity. Country is currently passing through social and economic transition.
The proportion of the population which is urban has doubled over the last thirty years (and is now about 30%), agriculture now accounts for about 25% of GDP and the economy has been growing at around 7-9% a year. Country has a highly seasonal pattern of rainfall, with 50% of precipitation falling
in just 15 days and over 90% of river flows in just four months
Desalination & Water Purification Technologies
Introduction:
The world’s water consumption rate is doubling every 20 years, outpacing by two times the rate of population growth. The availability of good quality water is on the decline and water demand is on the rise. Worldwide availability of fresh water for industrial needs and human consumption is limited.
Various industrial and developmental activities in recent times have resulted in increasing the pollution level and deteriorating the water quality. Water shortages and unreliable water quality are considered major obstacles to achieve sustainable development and improvement in the quality of life. The water
demand in the country is increasing fast due to progressive increase in the demand of water for irrigation, rapid industrialization, and population growth and improving life standards. The existing water resources are diminishing (i) due to unequal distribution of rain water and occasional drought, (ii) excessive exploitation of ground water sources and its insufficient recharge, (iii) deterioration of water quality due to the discharge of domestic and industrial effluents without adequate treatment. This is resulting into water stress/ scarcity. Country is currently passing through social and economic transition.
The proportion of the population which is urban has doubled over the last thirty years (and is now about 30%), agriculture now accounts for about 25% of GDP and the economy has been growing at around 7-9% a year. Country has a highly seasonal pattern of rainfall, with 50% of precipitation falling
in just 15 days and over 90% of river flows in just four months
An Introduction To Membrane Techniques For Water Desalination
This course is adapted from the Unified Facilities Criteria of the United States government, which is in the
public domain, is authorized for unlimited distribution, and is not copyrighted.
An Introduction To Membrane Techniques For Water Desalination
This course is adapted from the Unified Facilities Criteria of the United States government, which is in the
public domain, is authorized for unlimited distribution, and is not copyrighted.
Desalination and Membrane Technologies: Federal Research and Adoption Issues
In the United States, desalination and membrane technologies are used to augment municipal water supply, produce high-quality industrial water supplies, and reclaim contaminated supplies (including from oil and gas development). Approximately 2,000 desalination facilities larger than
0.3 million gallons per day (MGD) operate in the United States; this represents more than 2% of U.S. municipal and industrial freshwater use. At issue for Congress is what should be the federal role in supporting desalination and membrane technology research and facilities. Desalination issues before the 114th Congress may include how to focus federal research, at what level to support desalination research and projects, and how to provide a regulatory context that protects the environment and public health without disadvantaging desalination’s adoption.
Desalination and Membrane Technologies: Federal Research and Adoption Issues
In the United States, desalination and membrane technologies are used to augment municipal water supply, produce high-quality industrial water supplies, and reclaim contaminated supplies (including from oil and gas development). Approximately 2,000 desalination facilities larger than
0.3 million gallons per day (MGD) operate in the United States; this represents more than 2% of U.S. municipal and industrial freshwater use. At issue for Congress is what should be the federal role in supporting desalination and membrane technology research and facilities. Desalination issues before the 114th Congress may include how to focus federal research, at what level to support desalination research and projects, and how to provide a regulatory context that protects the environment and public health without disadvantaging desalination’s adoption.
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