Do you know what happens to your poo in your city? in Los Angeles, the waste water is treated, the poo removed, and returned to the Santa Monica Bay. The water is actually quite clean when the system is working properly. The poo is supposed to be composted in an aerobic process to minimize methane production. A process that breaks down the the waste with oxygen, the byproduct is CO2. However not all of this is done properly. Much of it is trucked to the desert where is is pilled up on Indian land. This process is anaerobic, that is without oxygen. This process produces methane and is not controlled. Neither of these is a particularly great solution.

The first process is good, because the CO2 that is produces is the same CO2, that was taken in from the atmosphere in the first place. It's just recycled CO2. The problem is the Humus, or soil that is left over. It's a perfectly good soil except for the 'ick' factor. Years ago, the city had a product called LA's best. It was a big bag of poo composted with the green wasted from the green bins. A great idea, but do you want the collective poo from your entire city in your yard? even if's only a few bags. It's a perfectly good solution environmentally.  You could grow organic crops with this stuff without using fertilizer. The problem is acceptance. My poo in your food.... hard to swallow.

The piling it up is unacceptable, It wastes money, effort, and energy. it has to be dried, loaded, trucked, and piled high. It has the potential to contaminate ground water, and it stinks. However, if the money where spent to build what is called a digester. The waste could be pumped into the system to produce methane, This gas could then be used to make electricity.  The leftover material drawn from the anaerobic digester is called sludge, or effluent. It is rich in nutrients (ammonia, phosphorus, potassium, and more than a dozen trace elements) and is an excellent soil conditioner.

Another solution is to build a serpentine pond, kind of like a folded river basically a big shallow tank with zig-zagging partitions, like the ones at an amusement park. The wastewater would flow though this "river".  The "river" would have water hyacinths floating on the surface. The trait that makes the water hyacinth a problem as an invasive species is what makes them great for wastewater treatment. The dangling roots pull everything out of the water leaving it clear. The plants are then harvested. They can be pelletized like rabbit food and burned to make electricity. Burning biofuels does not increase the amount of CO2 in the atmosphere, because it recycles the CO2 it took in while growing. The fibers have been used to make paper, and rope. They have bee used as animal feed. The beauty of the system is the simplicity and low cost.  The only byproduct is clean water, and biomass.

There are solutions to the human waste problem, that produce a positive outcome, without lingering time bomb like problems. Funny how the greener, more natural solutions, solve more problems than their industrial counterparts.