Schedule 80 pipe is pressure pipe that is equivalent to iron pipe in size and is generally used in interior plumbing applications.   SDR size pipe is equivalent to ductile iron sizes and is typically used for butied applications outside of buildings.  I've never seen a formula or table that gives equivalent ratings.   All you can do is look at the wall thickness.    Codes for sewer and water piping in buried applications are based on SDR ratings.   Your city guy sounds like an ex plumber.

you might check:

http://www.charlottepipe.com/products/Assets/03-Technical_Manuals/ABS_PVC_Technical_Manual/ABS_PVC_Technical_Manual.htm

Check tht relative strengths of the pipes. Sced 80 may not come in larger sizes. Also i think they all have glued fittings. Look in th ASTM's vol. 8.01 and 8.04. Most DOT's only call for SDR pipes.

I am requesting a wasteter pump with discharge 150gpm and TDH=125 ft, who can recommend a kind of pump. thanks.

Civil38.
Go to the pumping forum and post there. Add some more info also, wastewater make up, is this a small collector? etc. First guess. a grinder pump.