Human excrement and urine can safely be used from a composting toilet. It is a simple process to build your own Composting Toilet. It is important to know that your own urine is not a waste product, it is in fact a sterile product that contains only the things you find in food, or nutrients your body processes but doesn't use up at the time. This is an important lesson as it may save your life post pole shift.
Offered by Janar.
I suggest that you keep the manure separate, only hardy plants like tomatoes, jimson weed (motherwort), and mints can even tolerate such rich applications. It is best to compost human manure (human) with a composting toilet and compost pile, perhaps in combination with a worm bin (using moderate quantities of manure). Or better yet, set up an indoor toilet where your toilet seat and stall is set above a large tank (100+ gallons, depending on supply and usage) where the resulting manure can collect and be anaerobically digested (the bacteria in our intestines readily produce methane gas - that is why we fart - especially if you eat a varied diet with plenty of beans and vegetables). Have a standard gas line (1/2 inch copper tubing will do) with pressure gauge and valve/switch running to your gas stove, water heater, generator, gas refrigerator, etc.
Make sure you have some access to the tank, a sealed door on top or hatch, that will allow you to remove the byproduct of your efforts: A rich, dark powder ready to be mixed into soil or water for application. Be sure to vent or burn off the excess gas before you remove the stuff and wear some goggles and a mask, the smell may still be lingering, and have no flames or sparks present. You'll only have to do this sort of thing perhaps twice a year for a single family - if you expect more then have two tanks, one to keep you going while you empty the other. It is best to empty your tanks in late spring on a warm windy day. You may want to let the breeze into the home while emptying the tank. Perhaps you could situate the tank on the south side for maximum heat and anaerobic activity with access to the tank outside the house to avoid the above. Be sure to leave a little bit in the tank for residual bacteria to grow upon.
For a compost toilet, the anaerobic digester, to avoid the smell you must have two trap doors below your seat, both should be sealed and air tight. The order of business is this:
The space between the two doors should be about 1 ft. where a large metal pipe about 10" diameter should be used. For those of you worrying about microorganisms and bacteria, etc., the bacteria are what make the methane, they are already in your guts. If you would like to accelerate the process find the appropriate bacteria (similar, if not the same, to the stuff you might use for clogs in the conventional septic system - bacteria ready to reproduce and go to work) and add them according to the level of poop you have in the tank. For any other microorganisms you may worry about don't worry about them because they are not fit to survive in the dark, hot, airless environment of the tank - not to mention the methane bacteria will eat them up. Even if you have just a few hundred cubic feet of gas in 250 cu ft. tank the heat will cause a significant pressure build up.
Be sure to drain off the excess gas, when its time to harvest the tank. You'll have a fine dark powder to mix with solid or compost. Make sure it is dry when you get it out. (Maybe you would like to have a window or a floating gauge to check when its nearly full.) Also try to avoid urinating in the tank. A cup of pee may do little harm to a pound of poop or the bacteria, but don't do it all the time or let it add up. Our waste is separate for a reason, use it accordingly.
Offered by Steven.