San Francisco wants a digester... for dog poop.

​Everflux applied and was accepted into the San Francisco Startup In Residence (STIR) Program , on a challenge to build a dog poop digester in a city park.

Did you know San Francisco has more dogs than children? Yep, approximately 120,000 of them. And while many dog owners have learned the habit of cleaning up after their dogs, that dog poop ends up in plastic bags, in the trash can. Which means eventually it ends up in a landfill.

Seeing this as a huge public nuisance, and a brown splatter on the City of San Francisco's otherwise outstanding recycling record (the city has an ambitious goal of becoming zero waste by 2020) the Recreation and Parks Department included a challenge in this year's STIR program that called on a startup to find "a park-sized, affordable solution that could convert the methane from dog poop into electricity." We applied on a whim, thinking there was a small chance we'd be accepted. Well, good things often come by surprise.

But Everflux has been focusing on building anaerobic digesters for food waste. And the difference between designing a digester for food waste and dog poop is bigger than you might think. How then, would we pivot to dog poo?

The Park Spark Project in Massachusetts was the first dog park poop digester.

When we began doing research, we discovered that a few other cities around the world have attempted to solve this problem with dog poop digesters, with some success. Actually, it turns out building a digester for dog poop is easier than food waste. Because dog poop is a relatively homogenous material, the digestion process is not prone to upset as much as with very heterogenous food waste. Remember the last time you ate something, er, "different," and your stomach didn't feel well after? That's because digestion bacteria have a hard time adapting quickly to new food.

The biggest challenge. as we realized, would actually be getting dog owners to participate in the program. So Eric and I devised a system of rewards that would give owners an incentive to scoop, and recycle, their dog poo. By scanning a rewards card, or an app on their phone, every time they deposited their dog poop in a digester (inside a biodegradable bag), they could earn points. Those points would eventually get them discounts at local pet stores.

We've been surprised at how much interest this idea has received. When I mentioned the project during a lightning talk at the Manylabs open house on June 5th, to my surprised I received a mini-applause. Apparently people in San Francisco are sick of stepping in dog poop... or maybe they see the potential for it to become a resource, rather than a nuisance.