There’s a famous book, first published in Japan in 1977 by author Tarō Gomi, called Everyone Poops. This brief children’s book, first published in English in 1993, is intended to emphasize that excrement is a natural part of the human experience. Since the first humans roamed the Earth, dealing with waste has always been a problem.

Long ago humans were hunters and gatherers who relieved themselves wherever was convenient and didn’t have to worry about any consequences. The problem of human waste didn’t really exist until people started to gather and settle down in population centers. The first known cesspit dates to 4,000 B.C.E. Babylon. Basic water supply systems already existed, but modern archaeologists haven’t found buildings with “toilets” connected to a sewage system dating earlier than 3,000 B.C.E.

Those first toilet equivalents sent wastewater either to cesspits or the nearby Indo River. Early Greeks were known to pipe wastewater to the edges of their cities, where they’d use it as crop fertilizer. The Romans innovated with seated toilets (still little more than boards or brick boxes with a hole in the middle), though they mostly just threw their waste onto the street.

Sometime within the first couple of hundred years B.C.E., the Romans installed a lead-pipe sewage system — for a while, many households were able to dump waste directly into that system. However, as cities across Europe grew, many cities outgrew these systems and returned to public cesspits. This was horribly unsanitary. 

Arab cities, specifically in the Iberian peninsula, maintained sanitation rules, separating rainwater, greywater, and wastewater. Still, all that waste ended up in public cesspits. For centuries, as cities continued to grow more dense, there were no innovations in wastewater sanitation. It wasn’t until the 1800s that scientists started to fully understand how dangerous wastewater was and that cities really began to invest in sustainable sewer infrastructure.

Today, well-off countries and cities have fairly good wastewater systems. Many less fortunate people worldwide still struggle with dated and flawed sewage solutions. Some modern cities even have systems in place to collect, treat and reuse wastewater. With drought and global temperatures on the rise, there’s a need to capture and reuse as much good water as possible. Some scientists have found innovative solutions.

Natural wastewater treatment systems have been used sustainably and successfully for decades in various locations across the world. In the United States, this coincided with the passage of the Clean Water Act in 1972. The U.S. Environmental Protection Agency implemented pollution control standards and programs, particularly around wastewater.

With fresh government funding, environmental and sanitation scientists took the opportunity to innovate. Natural treatment systems are “those having minimal dependence on mechanical elements to support the wastewater treatment process. Instead, the systems use plants and bacteria to break down and neutralize pollutants in wastewater. Natural systems use, rather than ‘dispose of’, waste; and because they use natural processes, they minimize the use of chemicals and require little energy to operate.”

Ashes to ashes, dust to dust. Terrestrial lifeforms have been exuding waste for millennia; that waste has always returned and been reabsorbed by the Earth. It’s the concentration of waste in unnatural cesspits that’s dangerous, as well as the mixing of otherwise potable water with waste.

The four main types of natural wastewater systems are: spray irrigation; overland flow; rapid infiltration; and aquaculture. Each one works more or less well depending on the location. One example of a long-successful plant of the aquaculture (i.e., wetlands and marsh) variety is in the small city of Arcata, California.

The Arcata Marsh and Wildlife Sanctuary is a beautiful wetland park situated between the city itself and Humboldt Bay, which empties into the Pacific. For years, it was misaligned — essentially a dump. At the end of the 1960s, Humboldt State University professor George Allen began experimenting with wastewater aquaculture, farming salmon and other fish in the questionable waters. A few years after the passage of the Clean Water Act, the local Wastewater Authority proposed a treatment plant. Local citizens rallied for an integrated plant that utilized the natural processes of the marshes.

In 1979, state authorities authorized the local group to run a pilot program — and it worked. Today, the Marsh is both a public park and a wastewater treatment plant. There are educational resources and buildings within the park, to teach visitors about natural wastewater treatment.

There are nine steps in the treatment process at the Arcata Marsh. They’re separated into four main objectives: the separation of solids and liquids; natural purification; disinfection; and discharge. The result is natural waste management and a beautiful, thriving wetland environment.

It’s almost funny — from natural waste disposal with early humans, to unsanitary pre-industrial cities, to science-backed natural waste disposal. After thousands of years, city dwellers figured out that waste disposal didn’t have to be so disgustingly unsanitary.