I understand the banging noise in a sump pump system is caused by the check valve. However the noise I hear is at the opposite end of the pipe run, closer to where the pipes exists the house. Would installing an additional silent type check valve in the pipe run help?

EDIT: Never mind what I said below. I read the question wrong. :o

One of the cheapest and easiest options is to install a water hammer arrestor near the place where the banging is taking place. You can buy one at any home center or even make your own by simply teeing in a short length of capped-off pipe pointing upward so that it stays filled with air. The air acts as a shock absorber for the moving water when the check valve closes rapidly. The only real disadvantage to the do-it-yourself variety is that the air will eventually be dissolved into the water, so you may have to uncap it every few years and get the water out.

Yes, install additional Check Valve, close to the source of noise. Just be careful, noise travels. Therefore, you may hear it on one place while the it is generated in another place.

Jcaron must have misread the post, we do not use hammer arrestors on a sump pump drain, that would be weird

As soon as I hit "submit" I regretted it. :) I sure wish there was a delete button!

You should be able to EDIT by clicking the edit button below the answer box.

I'm just thankful you were nice enough not to give me a "reddie" for such an idiot answer.