I want to send and receive data wirelessly from 90 different areas to a central collection site. longest distance is 8.5 miles.
My suggestion is to use long-range Wi-Fi.  You want to use 5.8 GHz 802.1n, since that has twice the range of the more common 2.4 GHz Wi-Fi right of the bat.

You should put a omnidirectional antenna at your main location like this one which has a gain of 12dBi:



and directional antennas at your pump/lift stations like this one, which has a gain of 30dBi:



Since Wi-Fi routers are designed to work with local LANs which have 255 maximum devices (the lowest octet of an IP address), handling 90 devices should not be a problem, except I would set it up so that the communication from the pump/lift stations is staggered so they don't compete.