Cross Underground LV Power Line & Sewer Line

This should do nicely.

Where in this world are you located? Your local codes will govern how you'll cross other services and what depth.

If you don't know or understand that, your in over your head and should hire an engineer/contractor to do the work. It will be cheaper and safer in the long run

https://www.gtc-uk.co.uk/docs/default-source/electric---house-builders/gtc-electricity-technical-guidelines4.pdf

You research the appropriate regulations for the area you live in & research it & do as they specify as most countries & districts have different regulations.

Personally I wouldn't put them in the same trench no matter how far appart they are, as digging up 1 disturbs the other, often plans don't include both the sewer & electrical in the 1 plan.

I know this from personal experience having to go repair electrical cables after a person was digging up a sewer line & found the electrical with a digger.

Because of the location & the fall needed for the sewer line to allow a down hill flow it was much deeper than the electrical This in mind makes every situation different, shite won't flow up hill.

sorry solar I misread the OP & was distracted

but the first part does apply as the OP doesn't say location or country

Yes this is just meant as a generic guideline where no other rules exist....