Flush toilets allow us to avoid confronting just how archaic our sewage systems are. Ninety percent of the world’s sewage flows untreated into waterways and it’s making our environment, and us, sick. California environmental scientists estimate that sewage discharged at beaches in Los Angeles and Orange Counties contribute to up to 1.5 million excess gastrointestinal illnesses. In 1993, a feces-borne cryptosporidium killed 400 people in Milwaukee and sickened another 400,000 due to under-treated sewage in Lake Michigan.

The problem with our flush away system is that we just don’t have the capacity to handle all the waste (every week, New York City sends 800 Olympic sized swimming pools of sewage water into nearby waters). It’s also expensive and energy-consuming to treat our waste (Britain’s sewage treatment uses a quarter of the energy of the country’s largest coal-fired power plant).

Some countries are experimenting with alternatives to the flush toilet. Sweden has at least 135,000 urine-diversion toilets in use. Since urine is relatively sterile it can be then treated or even given to farmers (as is done with some of the diverted Swedish pee).

A sewage-free office building in Vancouver (Canada) uses composting toilets that whisk all waste away to a basement composter so there is no smell nor inconvenience. Thanks to the system, the C. K. Choi building uses just 500 liters (132 gallons) of water per day, instead of the 7,000 liters (1850 gallons) per day used by a similarly-sized conventional building.

For Oakland, California resident Laura Allen, her sewage-free bathroom is a bit more complicated. The urine from the urine-diverting toilet is used as fertilizer, but the feces is stored in plastic drums to compost. After a year, all pathogens are destroyed and the drum is filled with “humanure” which Allen uses on her garden.

In this video, Allen- a founding member of the Greywater Guerrillas– shows us her composting toilet, the stored poo and the surprisingly nice-smelling humanure.