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We're students in an Engineering Design & Development Class. We are trying to make it so people have a method of desalinating and purifying water in emergencies, camp sites, and other situations. Please post what you would want in a filtration device.
See Clarification below
Hi EDDperson91, I'm sure folks would be glad to help with your survey, But some folks are kinda' funny about talking to someone they don't know. Would you mind doing an introduction in the introduction section? Thanks.
To answer your question/survey.
Here are the things that would be ideal,(at least that I can think of) I realize that not all of it is possible/probable, however by trying to attain the impossible you can possibly attain something better.
Cheap, lightweight, high "Flow Rate", Easily maintained, Very few/no parts to replace, Easy to maintain in the field, durable, compact, Easily "adapted" to multiple types of containers/versatility, Ease of use in case of injury. That's all I can think of right off the top of my head. Let me give it some more thought,and if I can think of anything more that others don't beat me to,I'll add more.
I am a Mechanical Engineer, and for my senior project before graduation, we made a human powered distiller. I am also an avid backpacker. Here are some things to consider.
If you want to desalinate, there aren't many options. One is reverse osmosis, and the other is distilling. All back country water purifiers do not desalinate. They are based on killing the germs/bacteria in the water. If there is some type of chemical in the water, they won't get it out. You can filter out contaminates (meaning chemicals and heavy metals) but you need more than a one stage filter. In other words, you need to establish your scope more clearly. Right now it sounds like you don't know what you want.
Anyways, I work at an R&D company and my job title is Design Engineer. Since your class focuses on design, expect me to be hard on you. :sailor:
How large of a unit will it be or do you have any size constraints? Do you have any constraints on cost? We need a lot more info on your project.
And I'm the Quality Control Director around HERE, so expect me to be even harder on you. :sneaky2:Quote:
Originally Posted by finallyME
The bottom line, as FM noted, is that desalinators operate either by reverse osmosis or distilling. Just remember that either method may require additional steps. Let's look at our options:
Producing potable water from a salt water source (ocean, river, marsh, etc.) will likely require between two to four steps, depending on the method(s) used and the quality of the final product that you wish to achieve.
First, the water should be pre-filtered to remove as much of the particulate and solids as possible. No need to work with junk in the water if it can be avoided.
Second, the water should be desalinated. Removal of an absolute minimum of 96%, and preferably 98.5%, of salt should be achieved.
Third, the water should be filtered, preferably to a minimum of 0.2 microns, in order to remove MOST of the particles, bacteria, protozoans, amoebas, viruses, etc. Note that this will achieve some but NOT all purification of the water. Nonetheless, the water will most often be safe to consume at the 0.2 micron level.
Fourth, purification will be necessary to kill organisms smaller than that which your filter can remove, should you choose to be extremely careful. This may be advisable if treating water for infants or individuals with compromised immune systems. Boiling is the most reliable option - 100% effective - although some prefer chemical methods.
DISTILLATION - (The water should be prefiltered first.)
In essence, you're talking about using a still here. There are multiple advantages to distillation. Not only does this process desalinate, but it also achieves an extremely high level of filtration and it kills (purifies) all biological contaminates (bacteria, protozoans, amoebas, viruses, etc.) through boiling. The downside of using this method is that the equipment required is generally bulky and always requires some type of fuel, which depends on the design. This is probably NOT a good method to employ if camping, but will probably better serve your needs at a fixed location. But a gravity fed desalinator would be even better......... :innocent:
REVERSE OSMOSIS DESALINATORS - (This method will require steps 1 - 3 above (and step 4 if necessary by either boiling or chemical treatment).
IMHO, Katadyn currently makes the absolute BEST desalinators and filters on the market. (NOW watch the debate start. :innocent:) Here's the catch - the desalinators are EXTREMELY expensive, regardless of whether they are manually powered or electrically powered. For our purposes here, let's assume that electric power is unavailable (since we are hiking or in an emergency situation.)
Katadyn currently makes two manually powered desalinators. Both work by reverse osmosis. Both will likely cause your arm to fall off as well, even before you have enough water to meet your minimum needs.
The Katadyn Survivor 06 (Just under $1,000.00) has an output of 30 oz/hour (± 15%). Not that efficient.
The Katadyn Survivor 35 (Just under $2,000.00) has an output of 1.2 gal/hour (± 15%). Better, but not that efficient either.
http://www.katadyn.com/en/katadyn-pr...dyn-entsalzer/
Depending on how many people you are supplying, the chances are that either of the above will operated nearly around the clock.
There are thousands of designs for distillation systems available via a Google search. Every single one can also be used to distill alcohol, so most, if not all, are probably not legal to own. :innocent:
So here's my wish list:
I want two types of reverse osmosis desalinator designs.
One should be "higher volume" and gravity fed (like the Berkey two stage purifier design). http://www.bigberkeywaterfilters.com...cb750d70537394
The other should be manually operated like a Katadyn filter and be small enough and light enough to carry in your pack. Say under 5 lbs.
Each should pre-filter, desalinate, filter, and purify (in that order) water at a minimum output rate of one liter/5 minutes. Each should also be able to treat a minimum of 500 gallons before components require disassembly and cleaning and 10,000 gallons before components require replacement. Oh yeah - it should cost under $500.00 per unit and come with a lifetime guarantee.
EDDperson91, do you think you can get back to me with some preliminary designs by tomorrow afternoon? :innocent:
And before I forget, ALL products should be submitted to Quality Control (that's one for Crash and one for me :)) for testing and review. Just use our search function and type in the words "Quality Control" - with the quotation marks if you need further explanation. :)
It's illegal to distill water?
Actually, with the rate of the World population growth and growing lack of fresh water, desalinaters should be a priority.
UNITED STATES CODEQuote:
Originally Posted by LowKey
§ 5601. Criminal penalties
(a) Offenses Any person who—
(1) Unregistered stills has in his possession or custody, or under his control, any still or distilling apparatus set up which is not registered, as required by section 5179 (a); or
http://www.law.cornell.edu/uscode/26/5601.shtml
Guess they shoulda told my Physical Science lab teacher. Learned how to distill wood to alcohol, how to create hydrogen by hydrolyzing water, and chill distilling water for other experiments. Course the amounts of wood alcohol we ended up with might have filled a thimble.
She actually taught us several life skills.
Her name wasn't Mrs. Dennehy, was it? :innocent:Quote:
Originally Posted by LowKey
http://cnmnewsnetwork.com/12101/meli...sext-messages/
Not hardly...
Clarification: We are attempting to design a small, affordable, man-power unit with good water output for desalinating water
Thanks for the very productive input so far.
We have been considering using a RO system from the start of the project. You don't have to worry about cost as we currently have a $300 budget. We are currently defining our other contraints.
Okay then. :innocent:Quote:
Originally Posted by EDDperson91
How about just ..........
A manually operated device like a Katadyn filter and small enough and light enough to carry in your pack. Say under 5 lbs. - much heavier than a regular filter, but hey, it desalinates too, right?
The desalinator should pre-filter, desalinate, filter, and purify (in that order) water at a minimum output rate of one liter/5 minutes. It should also be able to treat a minimum of 100 gallons before components require disassembly and cleaning and 1,000 gallons before components require replacement. Oh yeah - it should cost under $500.00 per unit and come with a lifetime guarantee.
And just a reminder..........
ALL products should be submitted to Quality Control (that's one for Crash and one for me :)) for testing and review. Just use our search function and type in the words "Quality Control" - with the quotation marks if you need further explanation. :)
Quote:
Originally Posted by EDDperson91
I'm curious. Have you ever used one of these things before? They can give you a helluva' workout.
Are you guys in an undergrad program or are you doctoral candidates at MIT? And how about a more comprehensive intro? The more you tell us, the more we can help you.
I'm gonna' enlist FM's continued input on this subject. Chime in, FM, will ya'? And since his education's cost me the price of a yacht, I'll run it by my son as well - he's completing his masters in environmental/civil engineering. He designs water treatment and remediation systems. :)
We ain't just a bunch of weekend tenderfoots here. :sneaky2: Are we, guys? :innocent:
We're high school seniors taking a college course thru our school.
We have defined our criteria:
-has to filter out salt, giardia, and othe contaminents
-has to fit in an average backpack
-has to be man-powered (no electricity)
-has to cost under $300
-has to have a moderate water output [target is .2L/min,(thanks Ken)]
-has to be easy to use
We are now entering the design process, thanks for the input.
Hey, keep us posted, will ya'? :)
How about a longer handle and the ability to use it one handed? Also, how about a membrane that doesn't require pickling, or is easily replaceable?
Quote:
Originally Posted by EDDperson91
You need to nail down the specifics on size. "has to fit in an average backpack" is very vague. What is the size of an average backpack? You also need a weight target..has to be less than so many ounces, etc. Also, are you set on the flow requirements? You could modify that with a batch requirement, like it does 1 liter at a time and takes 5 minutes to treat the liter. Anyways, I could easily design a distiller that meets your requirements, but that would defeat your learning. :winkiss: I am not an RO expert, but they aren't that complicated. Distilling water is real easy (if you understand the properties of water).
So, do you have to use CAD, or just make sketches on paper? Anyways, the class sounds like my intro to engineering class.