What a brilliant idea. I wonder if the same method would be applicable for growing rice in dry areas?
It's not safe to grow veggies and grains with human manures.
For safety, the human manure should be used as an input feedstock for growing and expanding forest.
Then we use the forest's outputs as feed stock for grains and veggies and fruits and trees.
The forest outputs are leaves and wood, both of which may be processed into composts, or used as mulches for veggies, orchards, and grains.
This is what I practice.
This means I simply don't use human manure on my agriculture crops, I use it in my forested areas.
That said, I do use urine in my grass/leaf compost, and recently I started charging biochar with human urine. Urine is much safer that feces.
It's just a superstition but I wouldn't eat veggies grown directly in human manure (although the guy has done and hasn't gotten the sponge-brain: https://humanurehandbook.com/ )
Not true. My wife does research on this and post-sewage treatment dried sludge actually has better values than some of the food the used as reference samples.
I met someone once who after sinking tons of his own money into projects argued you need poop and some kind of toxins to keep people and their goats away for at least 30-50 years. His experience was that people destroying everything scales much faster than constructive effort. You turn your back and everything is gone.
Of course something is to be said for economically viable greening but if you just want to restore nature you should aim to do just that.
I don't have the numbers here but I found calculating how many large trees you need to sustain 1 human vs how much electrolysis it would take pretty mind boggling.