In the natural environment, everything is cycled. Animals eat plants and then poop. The poop decomposes back into the soil and provides nutrients to plants to grow again. Animals and plants die and decompose into the soil to provide nutrients to more plants and thus animals. The goal is to support this model of cycling of everything to create a circular system. One area we are losing many resources is in human poop and urine. We eat food, which takes resources, and then we go to the bathroom, which goes to sewage and is stored or put back into the environment after being treated. We can utilize the organic matter in human waste for other uses.
We can use human waste to generate electricity with biogas or hydrogen fuel. We can compost feces to use in farming or use urine as fertilizer. We can use feces as a food source for black soldier flies, which we can then use for feed for other farm animals and fish. We can make briquettes out of processed poop to use as fire fuel instead of wood.
If you are hooked up to the city sewage system, then ask your city or sewage processing company what they are doing with the human waste and advocate for utilizing it if they are not. If you have a septic tank, check with the company who collects the sewage. If you are not hooked up to central sewage processing, then you can look into solutions to install it on your property. Composting toilets are an easy one.
There are many inventions and people working on solutions for this, but it is not very mainstream yet. There are also serious precautions that need to be considered in order to do this properly to avoid any health issues. But we will need to figure this out and support these solutions so we can utilize this resource and support a regenerative circular system.