If u can pull it out u can spray with h2o2. You can also use excel. You could also do a bleach dip which I think is a 1:20 dilution with water and then cleaning with water overdosed with dechlor. Look on the forum as there is more in depth descriptions. Personally I would pull it out if possible and scrub with a toothbrush and dip it in h2o2.
If u can't remove it you can spot treat with excel or h2o2 using a syringe. Look up the safe dosing amounts of h2o2 if doing directly to the tank.
If you can remove the wood then scrape the BBA off with a dull knife and rinse the wood. It probably would be a good idea to try to kill any remaining BBA with H2O2 while it is out of the tank. You want to get its 'roots' off as well as the brush part. Even if you do stay on top of things and BBA doesn't return those little bumps aren't very nice looking.
Will BBA die off on its own with addition of co2?
I had most of my BBA die off after a 2 wee power outage, but I'm not sure how to get ride of the last few bits of it. It's also on pieces of wood that I really cannot take out of the tank anymore without disturbing everything.
If you cannot take out the driftwood:
Figure out how much Excel OR hydrogen peroxide is the maximum dose for your size tank.
Turn off filters, power heads and any other water moving equipment.
Use a syringe without the needle and squirt that much Excel OR hydrogen peroxide right into the densest parts of the BBA. If there is still a lot of BBA you might not get it all treated in one go.
Let it sit for a while, then turn the filters etc. back on.
The next day do a partial water change (25% minimum) and repeat. If you were not able to treat all the algae the first day, you could treat the remainder today.
When it turns pink, it is dead. Sometimes it takes 2 treatments like this to kill it. Sometimes it dies with just one treatment.
If you have so much BBA that it will take more daily treatments, then I would do larger water changes, practically drain the tank, then squirt or spray the Excel or H2O2 directly on the exposed BBA. The stronger concentration of either of these materials when the algae is in the air can kill it better that gambling that the water is still enough to maintain the concentration when you treat a full tank. When you do it this way (drain the tank, treat exposed algae) you can use about double the amount of H2O2. Then wait until the bubbling quits before refilling. Most of the H2O2 will have changed to water and oxygen so is not toxic.
If you can remove the driftwood many things will work. Then a good rinse and return it to the tank. Any of the materials listed are safe to add to the tank in the small amount that would cling to the wood if it was not well rinsed.