UV System Design

I made a UV sterilizer for a fish hatchery that was having problems with "ick", some sort of bacteria that rots living fish. It was pretty simple, UV is derived from a mercury vapor lamp. The glass used is Quartz glass which passes UV and is used as germicidal lamps in some hospital operating rooms and vent systems. Germicidal lamps are available from General Electric. The power requirements are like any other tube light. The method of application that I prefer for drinking water is to install the tube inside a pipe that is used to provide water. A "T" fitting at both ends of the pipe (plastic or metal) helps to contain the light and protect folks in the area from gazing fondly at the pretty violet light which is blinding. We were pumping 11,000 gallons an hour at the hatchery and set up an array of 24 tubes 4 feet long each. It took about 3.5KW to run the thing and it was set up above the water moving through the system so maintenance workers could easily see when a lamp needed to be replaced.

The system is still in use today and is located at the Mad River fish hatchery in Humboldt county California. I would provide the url but I can't seem to go fetch the info without loosing what I did here. UV is also great for sterilizing milk, apple juice and other liquifiable materials in a similar way. I have not seen it in use on a whole lot of products but I think it could be used much more extensively, especially in food preservation. UV sterilized bread, for example, bagged in plastic simply will not mould on the shelf unless the plastic fails.

Cobalt 60 produces gamma radiation and is used to sterilize many foods by simply moving truckloads through an area of exposure. Of course Cobalt 60 is extremely hazardous and is kept in lead encasement until in use. But its use is very economical.

I don't know many details, but my brother got a battery powered UV water sterilizer for Christmas. It is intended for backpackers; if I recall correctly, it will sterilize a liter of water in under a minute, and weighs just 3 ounces more than the empty container, including batteries. It may have been purchased at REI. If you want to know more, reply to this or dkwarner@mindspring.com and I'll find out more.

I am interested in learning where your brother purchased such a unit, because (1.) I am a backpacker/hiker, and (2.) I believe it may have utility in a combination system (with filtration and chlorination) in 3rd world situations.

email: dr_hhatters@hotmail.com

UV Water purification - Water to be purified by UV must be clear. Germs hide and survive if physically on the back side of suspended solid particulate. Use a mechanical filter if necessary to ensure water is clear.

Run the clear water through a four foot length of clear plastic tubing with the UV light a few inches away directed toward the water. If water clarity is questionable, increase tube length and bulb length accordingly. The UV light must make direct contact with each germ.

Shield eyes with UV glasses. Shield the UV light from public or naked eye view with a physical light obstruction. Extended eye exposure to UV light is similiar to extended eye exposure to direct sunlight.

Germ neutering is instant upon contact with UV light. Complete Purification or total germ death takes an instant longer. Four feet of length with 1/2 in clear tubing is adequate exposure with a fully intense new UV bulb. Replace the UV bulb annually even if the bulb is still working. The UV of the bulb intensity deteroriates enough to become ineffective if used for the full bulb life (many years). Annual bulb replacement ensures adequate bulb UV intensity.

For sources of UV lighting, check out the "plant growing lights" in the garden section. Many plant lights include UV bubls.

I wouldn't go for the UV technology to sanitize water if my project goes to third world villages. The problem with UV is that the powerful UV lamps you will need are quite expensive and deteriorate fast, besides, to transmit the UV radiation into the bulk of water you need high quality quartz tubes arranged in such a way as to allow close contact with every molecule of water, and on top of that, UV light is absorbed very fast in water and you will have a short length of effective UV light still powerful enough to denaturalize the proteins contained in microorganisms. UV sanitization works well in ultrapure water with the proper equipment and it is useless in "drinking water" if it has even the faintest turbidity or even traces of chemical substances other than H2O.

This technology is expensive, needs lots of power and is unreliable in poor water quality as you might find in these villages. Do they have a reliable power source?

I would go for the simpler and well proven technologies like a proper filtration system and then adding bleach. It is inexpensive and absolutely reliable.

Believe me, I've seen those villages and I know what water is.

I agree that the water I have to deal with in the villages is poor; however, I utilize coagulation, filtration and chlorination (to provide a residual pathogen kill capability). The water has no turbidity. Chlorination wont kill Giardia or Crytosporidium which is readily destroyed by UV.

Hi agua doc!

I agree with you (I didn´t took care of the water quality wich I know ), any way, somethig very simple and maintenace free must be don.

why don´t you try silver treated porous filters they can be made out of porous clay treated with coloidal silver and work by gravity force not only killing patogen germs but removing solid particles and with the help of an air hand pump they can be reto-washed.

I hope this will help!.

Suggestions?

Please ask CR4 for all the postings a few weeks back where there was a lively debate on "Water purification"

The undersigned strongly advocated distributed Electro Coagulation to solve world's 'Safe Drinking Water Crisis'- remove all bacteria, virus, smell, colour, smack, mineral salts, debris,clays,humics --in one pass.

If you want to commercialize in your country and need practical help ,I am available at mikemahant@hotmail.com

Hi!.

Try Strilaire UV sistems they can privide you with info and every thing you need in this field.

www.sterilaire.com

http://www.solarovens.org/ claim water pasteurization is possible with this simple device.

Cooks food too.

I thought this was a serious exchange of ideas about the best way to supply water to poor villages.

I've seen suggestions like a systems to sanitize air in confined spaces or ducts, or a small oven to heat water in a small container, hardly enough to supply the needs of a single person in a "as seen on TV" style, or some technologies needing odd equipments, power, and so on. Others are trying to make a sales speech.

Is this what it is all about in this forum?

I see this little solar oven is not sufficient for a larger group of individuals, but perhaps the scaling of it is possible. My thinking is that solar energy may be all that is available to some vilages.

Also, off topic:

I try to post in an appropriate on-topic manner and do believe in the FREE exchange of constructive ideas.

This is what this forum is for me.

And as others, I sometimes gain insight and knowledge, great!

If some make business contacts and make a buck solving someone's problems, I am all for it.

But this topic is far, far from my normal work and do not expect to ever make a penny ot of it. We are actually not involved in any fashion to the non-profit organisation I proposed.

My Name is Jordan Mbongeni aka PURe=mATIc2.

I have recently designed a cyclonic seperator animal washer,

Judging from the system requirements U need.

Maybe some of my design plans might be of help to you.

M on purebling@hotmail.com or purematics@hotmail.co.uk

Looking forward to your response.