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I've decided to buy a small ozone generator as a means of eliminating odours resulting from cooking. These wouldn't be permanently on, only used as and when required for the minimum length of time required (which I'm sure will be a matter of trial and error to determine).

 

Looking at two options.  Not much money in the grand scheme of things, but wondered if anyone had any thoughts / views:

 

https://www.ebay.co.uk/itm/Ozone-Generator-Ozonator-Sterilizer-Hygiene-Discharge-Air-Purifier-Home/232568538266?hash=item36262a449a:g:eiUAAOSwzppZ-C9q

 

https://www.ebay.co.uk/itm/2x-PLUG-IN-OZONE-GENERATOR-Eliminate-Odor-Kill-Smells-Air-Purifier-PLUG-/232544595432

 

 

 

 

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The principle certainly works.  We have a small battery powered one in the fridge, a German made unit that used to be sold via QVC: http://www.qvc.com/Genius-Air-Plus-Refrigerator-Refresher-&-Deodorizer.product.K29491.html and that works very well at keeping the fridge always smelling fresh, even when there's smelly cheese etc in it.

 

I've no idea about the Ebay units, but the larger one looks as if it might do the job OK.  I have built a few ozone generators from parts, when I was playing around trying to optimise the water treatment system, and now have a pretty powerful unit with an old PC fan that I've cased up and use to really blast a room with ozone if I need to get rid of a smell.  It works very well, but you can't stay in the room with it on, as it will have your eyes streaming and you'll be struggling to breath after a minute of so.

 

It does leave the room very clean smelling afterwards though, and does get rid of cooking smells very effectively.

Edited by JSHarris

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Looking at the output of fridge units, the larger 400mg/h unit would seem to be the way to go, plus it has a timer, presumably to prevent over use.  A 50mg/h plug would no doubt keep things fresh, but perhaps struggle to quickly eliminate odours from a 'shock' event like cooking. 

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The output from these things is largely mythical, in terms of true ozone generation, sadly.  They are tested with dry oxygen normally, which gives an output that is at least five times greater than the same unit operated in room air, plus any humidity reduces the ozone output even further.  As an example, the unit I've built that really blasts the room, uses plates that are rated (with dry oxygen) at 10g/h (10,000mg/h).  In reality, I doubt that it puts out much more than about 1g/h when operated in a room with air at around 40 to 50% RH.  That's still a great deal of ozone though, too much to stay in the room.

 

I'd suggest that the 400mg/h unit realistically generates around 40 to 50 mg/h under normal room conditions, and that is probably enough.  The 50mg/h units will probably only deliver around 5mg/h under room conditions, I suspect, and you may not even notice any effect at all at that low a level.

 

There are some other effects of ozone worth noting.  It is an extremely powerful disinfecting agent, around 10,000 times quicker than chlorine bleach at killing bacteria, viruses, cysts etc, as well as pretty much anything living.  The units needs to be located away from house plants, pets etc, and also not too close to people.  You can smell ozone at extremely low concentrations, well below the concentration that will really kill bugs etc, but if the concentration is too high it does irritate your eyes, nose and throat.  The good news is that it is very unstable and breaks down to normal oxygen very quickly, within about 30 minutes at the very most, and most of it will break down within a minute or so of having been produced.  This means that even if you do end up with a unit that is a bit too powerful (and I doubt that the 400mg/h will be) within ten minutes or so of turning it off most of the ozone will have gone, either reacted with the volatiles that create odours, or naturally decayed back to O2

 

I inject our well water with ozone at around 1g/h, and that oxidises the iron in the water in much less than 1 second and kills all the bugs within a few tens of seconds.  The iron oxidation is so fat that you can see the orange stain from the oxidised ferric chloride within a few mm of the point in the pipe where the ozone is injected.

 

 

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Thanks for this topic, I may have to invest in one of these for my boys rugby boots which do not smell pleasant.

 

and my car...

 

and the wife’s car...

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@JSHarris  That's very helpful, thanks.  Decision made.  Will give it a whirl and report back in due course.

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1 hour ago, daiking said:

Thanks for this topic, I may have to invest in one of these for my boys rugby boots which do not smell pleasant.

[...]

 

Learn to love it man! Won't be long before they've flown the nest and you'll miss it.

That deep visceral retching; only matched by a decent case of necrosis 

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6 minutes ago, SteamyTea said:

 

Who would want to be a teenager again!

 

ME, ME, ME, ME.🙋‍♂️

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2 hours ago, JSHarris said:

(...)

The iron oxidation is so fat that you can see the orange stain from the oxidised ferric chloride within a few mm of the point in the pipe where the ozone is injected.

 

 

Is that what the orange smudge is.... Commonly seen on slow flowing water courses ? 

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30 minutes ago, recoveringacademic said:

Is that what the orange smudge is.... Commonly seen on slow flowing water courses ? 

 

 

Usually.  UK ground water has a pretty high iron content and because the water is in deep aquifers, that are anaerobic, it dissolves as what is commonly called "clear iron", or ferrous iron.  As soon as ferrous iron in water is exposed to oxygen, or oxygenated water, it rapidly oxidises into ferric iron, which is bright orange (most people know it as rust.............).

 

In deep aquifers, along with ferrous iron, there is often sulphur and more often than not harmless anaerobic bacteria that use the iron and sulphur as fuel.  These bacteria can form clumps, but die when the iron in the water is oxidised, leaving behind slimy looking orange smears.  You may see smears and staining like this wherever water from deep underground comes to the surface.  It's extremely common in drains from old mine workings, and will often turn whole rivers orange.  The Red River, that flows from Redruth to the Towans just South of Godrevy Point, was red from the water flowing out of old mine adits (not sure if it still is, but it was very bright orange all the years we lived nearby)  Similarly, when Wheal Jane mine closed, and they turned off the drainage pumps (they used to pump the mine water into huge oxidation and settling lagoons in the Carnon Valley), the water level rose up to the level of the old adits and bright orange water heavily contaminated with iron(that turned it orange) zinc, arsenic and cadmium, flowed down the Carnon River and out into Restronguet Creek and out via Carrick Roads to the Fal.  It was an environmental disaster, that went on for months in the early 90's, with the whole estuary (which had been famed for its oysters) turning orange.

 

The bright orange dye stuff, known as ochre, is very fine ferric oxide, and was originally found from natural deposits, often near springs where water from deep underground bubbled to the surface.  The ferrous iron would oxidise as it came in contact with the air, and leave thick ochre deposits.

 

Ozone just oxidises ferrous iron to ferric iron very much faster than oxygen does, because ozone is far more reactive.  It isn't normally used in the UK to remove ferrous iron from drinking water, but is in the USA, where it is also often used as an alternative to chlorine as a disinfection agent.  Here we treat our drinking water with air to oxidise the iron, wherever we use deep water drawn from aquifers that contain ferrous iron (like Cornwall, for example).  Oxidation is an easy treatment, as a sand filter can be used to just catch all the insoluble ferric iron that precipitates out.

Edited by JSHarris

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1 hour ago, JSHarris said:

The Red River, that flows from Redruth to the Towans just South of Godrevy Point, was red from the water flowing out of old mine adits (not sure if it still is, but it was very bright orange all the years we lived nearby) 

Pretty good now.  I think SAS had a lot to do with getting it cleaned up.

Down near Levant Mine there is a stream that is a lovely blue from the copper sulphate.  I keep thinking I should stick a PV panel up and see how much I can electrolyse out.

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