Print this page Water Desalination
Vincent D. Reynolds, MBA, P.E.
Course Outline
This 5 hour course will discuss the various desalination processes including various chemical and mechanical pretreatment and post treatment processes that are used to make the water safe and pleasant to drink. Maintenance and disposal issues associated with the different types of desalination processes will be discussed. Design examples will be presented to aid in understanding the course material.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of course materials.
Learning Objective
At the conclusion of this course, the student would have learned the following:
- The total dissolved solids (TDS) contained in potable water;
- Total dissolved solids (TDS) in brackish water;
- The uses of Nephelometric turbidity measurements;
- How ion exchange desalinizes water;
- The optimum conditions for distillation/ condensation;
- The effects of emulsified oil and grease on desalination facilities;
- The best conditions for the use of cellulose acetate membrane;
- Gas wastes resulting from the desalination process;
- How electrolysis is used to desalinate water;
- How the absence of dissolved air affects the taste of water;
- The amount of energy used by various desalination systems;
- The various forms of chemical treatments in the desalination process;
- The most common used desalination process;
- Uses of polyphosphates;
- Ions that are removed with cation and anion resins;
- The desalination method that produces the most pretreatment waste;
- The major waste product from Ion-exchange systems;
- The most abundant element in seawater;
- The effects of reverse osmosis on product water;
- How to calculate the maximum recommended recovery rate;
- How carbon dioxide contributes to corrosion;
- The best conditions to use polyaromatic amide membranes;
- The best coagulants for desalination systems; and
- The chemical makeup of scale in desalination systems.
Intended Audience
This course is intended for anyone with an interest in water desalination, environmental engineering, water resources, city planning, chemical engineering or anyone wanting to know more information regarding water desalination
Benefit to Attendee
This course is designed so that the intended audience will benefit immediately with the information to aid in the effective design of Water Desalination facilities.
Course Introduction
The earth’s surface is replete with water with the majority of this water located in our oceans. The water in our oceans (seawater) has a salinity of approximately 3.4% and is not considered potable for human consumption in large quantities. In order to make seawater fit for human consumption it has be desalinized. Water desalination is used to remove salt and other solids from brackish and seawater to produce potable water supplies. Several variables are involved in deciding the most suitable location for a water desalination plant as well as which type of desalination will be utilized.
Course Content
This course will discuss the various desalination processes including various chemical and mechanical pretreatment and post treatment processes that are used to make the water safe and pleasant to drink. Maintenance and disposal issues associated with the different types of desalination processes will be discussed. Design examples will be presented to aid in understanding the course material.
A Short review of Ions in Seawater:
Ions can be described as cation and anions and they are the result of atoms losing or gaining electrons. Cations are ions that have a positive charge and anions are ions with a negative charge. Cations have more protons than electron thus giving it a positive charge. Anions have more electrons than protons and as a result anions have a positive charge.
The charge of ions is indicated by a positive or negative superscript placed after its symbol. The following are cations and anions that can be found in seawater:
Cations:
Hydrogen (H+)
Sodium (Na+)
Magnesium (Mg++)
Anions:
Chloride (Cl -)
Sulfate (SO4 =)
The following table gives the approximate molal composition of seawater:
Total Molal Composition of Seawater (Salinity = 35)[1] |
|
Component |
Concentration (mol/kg) |
H2O |
53.6 |
Cl− |
0.546 |
Na+ |
0.469 |
Mg2+ |
0.0528 |
SO2−4 |
0.0282 |
0.0103 |
|
K+ |
0.0102 |
0.00206 |
|
Br− |
0.000844 |
BT |
0.000416 |
Sr2+ |
0.000091 |
F− |
0.000068 |
The student will be directed to study the document “Water Desalination,” published by the army corps of engineers which also serves as a document for the Unified Facilities Criteria (UFC).
Please click on the above underlined hypertext to view, download or print the document for your study. Because of the large file size, we recommend that you first save the file to your computer by right clicking the mouse and choosing "Save Target As ...", and then open the file in Adobe Acrobat Reader. If you still experience any difficulty in downloading or opening this file, you may need to close some applications or reboot your computer to free up some memory.
Course Summary
This course is designed so that the intended audience will benefit immediately with the information to aid in the effective design of Water Desalination facilities.
Using good engineering judgment is always paramount in any situation. Utilizing good judgment and the knowledge gained in this course will aid the reader with the knowledge to design efficient water desalination facilities.
Related Links
For additional technical information related to this subject, please visit the following websites:
http://en.wikipedia.com/wiki/Seawater
US Army Engineering Publications:
http://www.army.mil/usapa/eng/
Unified Facilities Criteria:
http://www.wbdg.org/ccb/browse_cat.php?o=29&c=4
Environmental Protection Agency (EPA):
http://www.epa.gov/
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
