Q:

Green Film Build up in Glass Water Bottle

So I have this Large Water Jug that I fill only water with. 
And this is the 2nd time there has been a layer of green film that builds up at the bottom of the bottle. I don't have any way of getting to the bottom to clean this. 
I wanted to know.

What does this green film consist of?
What Chemicals or methods can I use to remove the film without having to manually scrub the bottle?

Thanks
ps. not sure if this was the correct place to ask this question.

A:

What seems to be forming in reusable water bottles and water coolers is a biofilm. Since it is a complicated system, after maturation biofilm might be very hard to remove without scrubbing. There is a nice article about cleaning water coolers, which might give you some information.
If you look closer on the Google Scholar search results, you'll find that quite a bit of research has been conducted in the area of sanitation of water coolers and study of their flora. For example, consider the following paper from 1996: Analysis of the Virulence Characteristics of Bacteria Isolated from Bottled, Water Cooler, and Tap Water.
There is a very nice list (Table 1) of different bacteria isolated from water. But I would like to point your attention to following table from the paper:

Quote from methods section listing tested antibiotics:

The
  natural and first generation antibiotics included:
  penicillin, ampicillin, erythromycin, kanamycin,
  streptomycin, tetracycline, chloramphenicol, and
  sulphonamide. The synthetic and later generation
  antibiotics included: gentamicin, cefoxitin,
  cefoperazone, oxacillin, piperacillin, imipenem,
  ciprofloxacin, and sulphonamideftrimethoprim

The green slime you observe, I think, is a combination of all those bacteria, plus some that were brought after the water was poured into the container. And it seems that all commercial sources that you didn't purify yourself, will have a variety of microorganisms growing. And around 5% of the total bacterial cell mass is resistant to common antibiotics.

