They will eat some waste I'm sure wil will help a bit, but eventually they will either die or morph into the adult midges and fly off. Im they weren't trapped in the filter itself I wouldn't worry much about them, they will mature out and fly out of the tank, if they start dying in the filter they will add to the waste. If there aren't many of them I wouldn't worry, if there are quite a few I would scrape them out of the filter, bag them up and sell them to your fellow fishkeepers for a few dollars. They are a good food for many fish, it's too bad yours ignore them.