Water Softener Drain

[Joshkrue]

I am currently in the process of planning a water softener installation, and have ran into a drain issue, or so I think. My water main shut off is in my garage, and the only exposed plumbing to tap into is just after the shut main shut off. The problem is my garage does not have a drain in it, and I am trying to figure out what to do about the two drain tubes the Whirlpool water softener I am looking at requires. Here is a picture of the set up:

The hole on the left does lead outside to a PVC cap, but can someone assist with telling me if this would be suitable for use for both drains, and the best way to utilize this? I was considering putting a basin in the garage for both drain tubes to use, but I am not sure that hole is large enough to accommodate the drainage.
Unfortunately outside my house, this doesn't lead to a drain, so I would have to cross that bridge as well. I appreciate any assistance anyone can provide.

 

[CountryBumkin]

What Whirlpool model are you looking at. Seems unusual to me to have two drain pipes for a softener. I think you may be looking at a "drain line" and an "brine tank overflow line". If so, the overflow line is not going to work if it plumbed above floor level as it is gravity drained (the regeneration drain line can be above floor level - like a standpipe since it drains under pressure).
My comments are based on the Whirlpool instructions ( I just looked at the "WHESCS" model) says the unit only uses 3 gal. of water during regeneration and the drain flow rate is 2.0 gpm. I'm not a plumber.