....

Currently, only one gold standard for sanitation exists: the combined sewer system that is already in place in developed cities. In a September post for The Atlantic, author Mary Anna Evans describes the initial design of this “modern” technology:

The EPA calls combined sewers “remnants of the country's early infrastructure.” The first sewers weren’t designed to handle the constant and huge stream of wastes from our toilets, because they were invented when we didn’t have any toilets. Sewers were originally built to solve the problems of cities that were flooded with their own refuse—garbage, animal manure, and human waste left in the open rather than in a privy or latrine—during every rainstorm.

The fact that cities still rely on a technology that predates toilets points to just how archaic this system has become.

....

If developing nations are turning toward new sanitation technology, why isn’t this shift happening in developed cities as well? One obvious explanation is that developed cities already have a functioning sewer system. But the real answer, Arbogast says, goes beyond the fact that “developed cities aren’t really innovating.” He contends that new technology will have to be tested in developing nations before developed ones are likely to follow suit.

“I firmly believe,” he says, “that if this technology can get out there in the market [in developing countries] … you’ll start to see building codes changing to incentivize the use of waterless toilets or to take the load off waste water treatment plants.”

Until then, it’s developing cities that require the most attention. The World Health Organization reports that 3.4 million people—mainly children—die each year from water-related diseases like cholera, dysentery, or typhoid. In a city like Dhaka, Bangladesh, Arbogast says, only 2 percent of waste is being treated at a plant. And in many cases, septic tanks carry human waste directly into the street—leaving city residents exposed to numerous pathogens. “No community has ever put themselves out of poverty without addressing sanitation,” Arbogast says.

....