Dear,
Thanks for the comments and clarification.
I already have a household UV system associated with active carbon filters and polypropylene but intend to mount another system but thinking about a cheaper and affordable solution for domestic use in poor communities.
I thought LEDs UVC would be a competitive alternative with mercury vapor lamps, but it isn't yet.
The prices of commercial UV systems, where the UV lamp and quartz tube are inside a flow cell of "stainless steel" are not cheap, I mean, it's not an affordable alternative for home use in poor communities in many countries.
So I started thinking about alternative ways, cheap, efficient and easy to be assembled by adapting components already commonly used in these communities.
So I thought I'd adapt within a clay filter (http://www.ceramicastefani.com.br/ingles/filtro-stefani/filtro/12/classic-filter-) a mercury vapor lamp inside a quartz tube (closed at one end) dipped in the bottom half of filter.
This could be done by sticking the quartz tube to the top half of the filter.
The water in the bottom half would be being irradiated by UV continuously.Would have to assemble an electric contact between the upper and the lower reservoir as a mechanism of protection by cutting electricity to
lamp and thus turning off the lamp whenever anyone tries to lift the upper part of the filter.
lamp and thus turning off the lamp whenever anyone tries to lift the upper part of the filter.
The clay material of the filter would be inert to UV and not liberate photodegradation products as could happen with plastic material.
I believe that, depending on the size and power of the lamp chosen, it could cost ~30% of the price of a commercial system (with stainless steel flow cell).
But another question is how to evaluate the minimum residence time of irradiation to ensure a efficient disinfection without expend too much energy unnecessarily.
I believe that, depending on the size and power of the lamp chosen, it could cost ~30% of the price of a commercial system (with stainless steel flow cell).
But another question is how to evaluate the minimum residence time of irradiation to ensure a efficient disinfection without expend too much energy unnecessarily.
I don't have a microbiology lab so I was wondering if would be possible to use some natural dye (eg: from vegetable) to determine the minimum irradiation accompanying the photobleaching (https://en.wikipedia.org/wiki/Photobleaching) of the dye.
That would be a simple chemical indicator to determine the minimum time of irradiation for lamps with different potencies and reservoirs of different sizes, ensuring sterilization and saving energy.
Any tip?
Thanks for the attention,
Markos
Thanks for the attention,
Markos
Em 29-11-2016 04:53, MC Ants escreveu:
I used to be really into reef aquariums and now I work in municipal water. UV disinfection for aquariums and ponds have been around for around 25 years and basically consist of a UV bulb in a quartz sleeve and water being pumped into the chamber, usually in a coil fashion to maximize contact time. The industrial size treatment we use for the city are essentially the same principal, but on a ginormous scale. There are also built in wipers to clean the quartz sleeve, as any buildup that obstructs the UV will essentially inactivate the disinfection.--
I currently use a UV-C CFL from Amazon to disinfect materials that can't be autoclaved. As Patrick said, it can be very dangerous. UVC + O2 = Ozone which can also be hazardous. I have some visible UV LEDs I used for another project that work well, but I haven't seen UVC LEDs for sale yet. What is your final goal? Maybe we can help with some additional ideas.
On Monday, November 28, 2016 at 11:10:50 AM UTC-8, Patrik D'haeseleer wrote:UVC disinfection for water sterilization has been around for quite a while. In fact, you can buy anything from industrial-scale UV water sterilizers, all the way down to portable "Steripens" for backpackers.
As you discovered, one issue is how low efficiency the UVC bulbs are, which means you pay a lot in electricity cost, and you have to dissipate a lot of heat. Another important limitation is that you need to expose the bacteria to a sufficiently high dose over time to be effective. So it's much easier to expose a bottle of drinking water to constant UV light for a minute, like the Steripen does, than to slap a big LED on the side of your water mains and expect it to be effective.
If you are going to tinker with mercury vapor lamps yourself, BE VERY CAREFUL! Shortwave UVC light is as good as absent from natural sunlight, and can burn out your retinas in a matter of seconds - especially if you work with a strong point source like the 125W bulb in the link that you posted!
(For the same reason, NEVER work at a biosafety cabinet with the sash raised while the UVC germicidal light is on! The glass sash will block most of the UVC, but you can still get a bad sunburn on your arms, or develop the equivalent of snow blindness from the UVC reflected off the stainless surfaces.)
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