Drainage hole in basement backs up (caused by pump filter?)

zenox

Hello,

I recently purchased a new home (its about 15 years old). The house is on its own septic and well (no city water). In the basement near the well pump there is also a large blue container that I've been assuming is some sort of filter. Additionally there is a hole in the floor that the filter has a nozzle going to. My assumption is that the filter rinses itself out every so often (seems to be every ~30 days or so).

Image here: http://imgur.com/nWC8G

The problem is, every once in awhile this seems to backup. Instead of the water leaving the house, it goes into the basement (not very much, but I would like to fix it).

So I guess my two questions would be:
1. Any suggestions on how to go about fixing this? From what I have read a sumppump may do the job (which I may do anyway), but I've heard that I should be able to clear this up other ways?
2. What is the large blue container? Is it a filter?

Thanks!