My parents have a house and some land in a rural area in MO (which is unfortunately becoming de-ruralized). Currently they have a septic tank system and all is well. There are no issues of water overflowing, backing up, storm-water run-off, or flooding; it's a very Earth-friendly property.
A regional wastewater sewer intercept project is being discussed in local governments so there's the possibility of this happening. I'm worried that trees would have to be cut down and my parents having to pay for costly fees.
The project says, "Property tax rates will not be affected with approval of the bond issue. Properties with a septic system will not pay for this project."
But that doesn't necessarily mean they will be completely clear of other costs for the changeover (I think). I don't know anything about septic tanks and wastewater sewer systems other than septic tanks need to be filled with sand or gravel when not being used and sewers add value to the property (which is NOT important b/c selling is a big fat NO).

How are wastewater sewers constructed (i.e. digging, use of concrete, etc..), and how are systems changed over from septic tank to sewer?

Good question Goldie!

How are wastewater sewers constructed (i.e. digging, use of concrete, etc.. ), and how are systems changed over from septic tank to sewer?
I went through the same thing in my area back in 74.
Most areas mandate that the top of the septic tank be caved in and the tank filled with dirt. The present sewer house outlet's converted to PVC and dug in the ground out to th street connection.where it connects to the county sewer. Your parents will bear the cost of installation and filling the tank but will save on tank and drainfield maintenance . Good luck and thank you for rating my reply. Tom