As for Dad's disposing of sewage and mining it in the process:
It may be possble to create a series of large but shallow cement ponds with drains and fill them with sewage water (no
large solids).
These ponds could then be covered with a digester and the methane gas could be collected or one could produce algae.
The algae could be allowed to grow as the sewage digests and once the algae reach peek production, the pond could
be drained of the septic water.
The algae would be left to be swept or pushed into a container for collection.
Once collected, it may possible to convert the algae to biodiesel with the systems on the market today.
with an 
