Is there anyway to filter the water in a cylindrical fish-bowl?

I recently moved one of my bettas into a smaller set up for my studio desk. It's basically a giant glass jar that I bought at wall mart that holds roughly 2.5 gallons of water with 3 lucky bamboo stalks growing out of a gravel and sand bottom. I was wondering if there is just a way I can install a filtration system into this thing so I dont have to do water changes every other day.