Circular Sanitation: How Human Waste Could Replace 25% of Global Fertiliser with Taylor Zehren

Recycling human waste rarely makes the sustainability spotlight, yet our current recycling system flushes away 32 billion gallons of fresh water and the nutrients that could replace a quarter of global fertiliser demand. In this episode of Hardware to Save a Planet, host Dylan Garrett speaks with Taylor Zehren, cofounder and CEO of Wasted, about how rethinking human waste can unlock a powerful circular sanitation economy. Zehren explains how urine-diversion technology turns porta-potties into nutrient-recovery hubs, reducing water waste, cutting emissions, and replacing a significant share of global fertiliser demand. She highlights why separating waste at the source outperforms traditional wastewater treatment, how Wasted’s model transforms disposal costs into revenue, and why cultural shifts, starting with educating children, are essential for scaling sustainable, nature-inspired sanitation systems across homes, venues, and communities.

In this episode of Hardware to Save a Planet, host Dylan Garrett speaks with Taylor Zehren, co-founder and CEO of Wasted, about how rethinking human waste can unlock a powerful circular sanitation economy. Zehren explains how urine-diversion technology turns porta-potties into nutrient-recovery hubs, reducing water waste, cutting emissions, and replacing a significant share of global fertilizer demand. She highlights why separating waste at the source outperforms traditional wastewater treatment, how Wasted’s model transforms disposal costs into revenue, and why cultural shifts, starting with educating children, are essential for scaling sustainable, nature-inspired sanitation systems across homes, venues, and communities.

What you will learn:

Why urine diversion at the source outperforms end-of-pipe nutrient recovery
How to leverage existing logistics infrastructure to scale nutrient collection
The biomimicry principle behind separating waste streams
How to design for adoption without requiring behavioral change
Why circular business models create better unit economics than linear waste disposal
The cultural and psychological power of making nutrient cycles visible

Taylor Zehren is the cofounder and CEO of Wasted, a circular sanitation company reimagining how we collect, treat, and repurpose human waste. With a background in biology and international development work through her Fulbright scholarship, Taylor founded the nonprofit Do Good Shit to deploy sustainable waste management systems in remote outdoor locations before scaling her impact through Wasted. She combines scientific rigor with biomimicry principles to tackle one of society's most overlooked climate challenges: transforming sanitation infrastructure into a nutrient recovery system.

Episode Resources:

Taylor Zehren on LinkedIn
Wasted Website
Dylan Garrett on LinkedIn
Synapse Podcast Website
Synapse Website
Hardware to Save a Planet Apple Podcasts
Hardware to Save a Planet Spotify

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