Just 30' to the septic system? Seems like you really over-complicating this. As already said, just get you 30' of sewer hose (or PVC pipe as one person suggested), and connect the trailer's sewer drain directly to your septic tank clean out.
No need to make it any more complicated than that, especially if its a downhill or level run to the septic tank. If its uphill, then the macerator pump and 3/4" hose would be the way to go. Still would be way cheaper and easier than using a huge, heavy tote tank.
You are fortunate, really. I have much more difficult situation at my house. RV is parked about 100' from septic system clean out, and it (RV) is at bottom of the hill, so its uphill getting to the sewer clean out. Nobody lives in the RV while parked at home, but there are times when we get back from camping trips that I need to empty the black tank.
I bought a 42 gallon 4 wheel Barker tote tank for this. Works OK, but lugging that tote tank 100' up the hill when its full, is brutal! Took two of us to do it and it was not fun, haha. Have only done it once, and decided then that there must be a better way. Thinking of rigging up some ropes and pulleys to pull the tank up the hill, since there's plenty of trees around to anchor to. Still thinking on that one, but point is, your situation is much simpler than mine.
🙂
Will and Cheryl
2021 Newmar Baystar 3014 on F53 (7.3 V8) Chassis ("Brook")
2018 Jeep Wrangler JK ("Wilbur")