You are not an organist, I presume. There are a couple of issues here with the playability of the piece. A lot of your pedal writing is too quick and too constant. Remember, the feet are playing this part. You simply cannot write the second half of measure 11 like you have, for the pedals. An organist will die. And that's not good. Hell, I wouldn't even be able to play all the 8th notes, and even a professional would have a heck of a time with it.
Starting with measue 44, you give the pedals all these repeating notes. This will result in the performer shaking like crazy all over the organ bench, which will engage the audience tremendously, as the wonder whether he will fall over and break his neck.
It is simply too fast for the pedal part you have. I suggest overhauling the part and slimming it down quite a bit. Pedals are, after all, SUPPORT to the manuals' play, and should be treated as what they are: really low notes that are played by the most underused limbs in music.
Besides all that you have a nice, C major piece that seems to flow nicely and that works decently. It's not my cup of tea, but I saw organ and came running. One other thing: in measure 74 you borrow from a modal/minor key and then quickly revert back to B natural. This is not what theorists like to call 'common practice', as it confuses what the leading tone(B natural in this key) is, and kind of sounds odd. Plus, towards the end there should be tension, which is moreso created by the leading tone than the more ambiguous flat 7, which suggests not an end, yet a modulation to the subdominant. And you don't want that.