Justis,The Western Treatment Plant in Werribee treats around...

Justis,

The Western Treatment Plant in Werribee treats around treats about 52% of Melbourne's sewage, or about 415 million litres a day.

Ok so Werribee treats 415m ltrs = 311.25 million ltrs of Hydrogen, now the way it is written one assumes that from 415 million ltrs of liquid sewage, three quarters of it is liquid Hydrogen, well it is not, it's gas, so only a very small percentage of the sewage is Hydrogen.

Now what does one need to add to the sewage and at what cost to obtain that small percentage of gas.

Don't you think that if it was as simple as you make it sound, every city or large town would already be using it.