The very concept of "garbage" is a violation of the law of gravity. Only Elon Musk, owner of Space-X corporation can actually "throw garbage away" and not have it come back to earth, and even he can only put it into orbit, not send it to some distant star to be consumed by nuclear forces. What we eat that is not digested and put to use by our bodies is not "garbage", nor is it problematic "waste".

Sewage is a resource. Some people are making the analogy that water is more precious for our future than oil. I certainly agree with that. I also believe that sewage is and will continue to be more valuable than diamonds.

Sewage is full of urea, the same molecule used to synthesize fertilizers. Indeed before modern chemical companies started synthesizing urea based fertilizers, pig urine was a principal contributor toward re-nitrification of cropland soils. Manure spreaders that distributed whole the various animal droppings on fields to produce more fertile ground for the following year. They often didn't have enough in total to cover their entire farm every year so it was added every third, fourth or fifth year, which usually proved sufficient to sustain healthy growth rates. Chemical fertilizers, applied yearly, of course, were designed to maximize growth every year. Urine rich sewage water could be treated with UV and Ozone to eliminate disease vectors (as drinking water is) as it is pumped into trucks on the way to either farms or fertilizer factories.

The same applies to sewage sludge, full of proteins, starches (carbohydrates, which like cellulosic sugars can readily be converted to hydrocarbons for use as transportation fuels). So, in effect, sewage systems, by way of analogy, are like a river of diamonds flowing directly into your "factory" as a "no cost" supply of feedstock as soon as the collection system is built.

Sewage collection could be a profit center rather than a cost center for a municipal government. The revenue derived justifies the capital expense of developing modern sewer systems in line with UN Millennium Development Goals, and their maintenance and operations and expansions as well. When sewage is a "for profit" enterprise (or at least operated as self-sustaining, without any additional tax burdens) it takes away the excuse to not follow through on MDG's for better sanitation (and not just coincidentally cleaner water resources as well) doesn't it?

Eventually, the remaining water is at least clean enough for "grey water" uses, but potentially could be "recycled" in a potable water system, too, since standard filtering, and UV & Ozone sanitation would render it safe, right?

Why are planning engineers not presenting robust sewage planning to politicians in this light? Even if the economic threshold of profitability is not present at the time of construction, inevitable urban growth will get them to that threshold, probably long before the 30 year public/municipal (in US, tax free) bond comes due. Isn't it true that whether it is for Soweto, South Africa, or Bangor, Maine, the same long term planning and implementation of a revenue generating resource system could be applied to sewage systems around the world?