Hey - that is a stinky problem! There's nothing worse than a "fog dart". The one good thing is that at least you have a scape goat for your own ... uh... smells. Just make sure the dog is actually in the room when you blame him. (I made that mistake once and lost my scapegoat forever more.)
I'm surprised your vet told you not to use beano. Any particular reason? We recommend it regularly in the teaching hospitalas it is non-toxic to animals and works in them the same way it does in us. (I'm just entering my last year of vet school - I'm trying to learn knitting as a way to increase my surgical finger dexterity.
) The active ingredient in beano is a natural enzyme called alpha-galactosidase which breaks complex sugars (the ones that ferment and make gas) down into simple sugars (like glucose and galactose) - that we or the dog can utilize quickly. I used to have a farty cat that benefitted from a few drops on his food once and a while.
My information certainly shouldn't trump your vets (as she has graduated and I have not), but it's something to ask about if you're curious.
Another very good nutritional supplement is something called "Fortiflora" that you can get from your veterinarian. It is basically the veterinary version of "acidophilus" - active microorganism cultures, but they are enteric organisms naturally occurring in the canine gut. It's a nutritional supplement too. Good stuff. Purina makes it. A vet can prescribe it.
There is a feline version that I can vouch for. I give it to my cats for small upsets and they clear right up. It's great for diarrhea in particular.
For something you should be able to find in the local PetSmart type store - charcoal biscuits may help. Though remember, they are black so your dogs poop may darken too.
Another drug option that is safe for dogs is Simethicone - the active ingredient in GasX. You can get the people pills from your local drug store or there are dog specific formulations that are pastes and gels with flavor (and expense) added.
As with any information provided on the internet by a total stranger, please do not use it in place of veterinary supervision/advice. I mention these things only as ideas that I had not seen in previous threads. They may merit discussion with your dogs veterinarian.
Most important is whether or not your vet has determined a reason for this new change in your dogs digestive ... status. Depending on the size of your dog and the age he was when you adopted him, this may be a normal aging change or it could be signs of impending illness. Off the top of my head... flatulence could point to anything from nothing to worry about to some fairly serious digestive and pancreatic disorders; a possible cause is worth looking into if only to assure yourself that it really is nothing to worry about.
Oh, and Mike is certainly correct about the ruminants. They fart methane.