sewer pipe across a waterway, how? Drainage and wastage systems and plumbing help, advice and answers

[skier-hughes]

I am preparing to open a caravan club cl site. To do so I need to provide a place for visitors to pour away their chemical toilet waste.
I have two options, as far as I can see.

1. To dig a deep hole and site a cess pool. Pros, plenty of land to sit it in. Cons ongoing cost of emptying

2. Connect to the main sewer system. Pro, no ongoing costs. Cons - I have to cross a moat to get to the mains sewer.

I've had a rough measure and the length of pipe would be about 30m from sewer connection to waste receptical.
I can get enough fall on the pipe - 40.1? - to make this work.
How do I support the waste pipe crossing the moat?
I thought of an RSJ and hanging it underneath, is this feasible?
Are there any other types of material I should consider?
This is nowhere near my area of expertise, so I'm open to all ideas :P
Moat is about 10m across.

I'm not worried by looks as this will pass through some trees so won't really be seen if I place it where I want to. Second option is to move it to somewhere slightly less wide adn use the RSJ as a base to make a bridge - sometime in the far future probably!!!!!

Are there any other things I need to look at.

Cost is obviously an issue, but I'd rather spend a bit and get it done not to worry about it again than have to mess about in a few years.

Graham

[thedoctor]

Speak to the Building Control Dept of your local Council. This drainage work will require permission in the form of compliance with the building regulations. They must know at all times what drainsd are laid and where they go.

[skier-hughes]

The BCO has just phoned back and they don't want to know. He said it's nothing to do with them, but to contact our local water authroity to see if they had any concerns.

How about any ideas on the practicalities of laying the pipe over the waterway?

Anyone done anything like this?

Maybe I should cut down one of the trees and use this instead of an RSJ, at least it is already in-situ :P

Graham