Without seeing a picture, by your description I'd say that the white rice things are springtails which are all part of the microherd that help to break down any food that's introduced. I always find afew of them in the catch trays.

On the other hand, if you're adding too much food, then you're bin is too wet and what you might be seeing is white mites which are an indication that things are too wet in your bin. Adding some dry shredded newspaper and holding off on feeding will dry things out and get rid of the mites.

There's no need to add hydrated lime to your bins. I add dry crushed eggshells which can be pulverized with a rolling pin or a coffee grinder. A tablespoon everycouple of weeks or so is all you need, but it's not absolutely neccessary. After 2 years of vermicomposting I've never had any major problems. Hope this helps. Good luck.

mataka4

Never add lime, especially hydrated lime to a worm bin!
If you are troubled by these inhabitants, harvest the worms from the bin and start over.