What is Milorganite?

By Jaime Staufenbeil - Milorganite Agronomist
March 3, 2017

Milorganite microorganisms, microbes, bugs

Let’s start with what Milorganite isn’t. It is NOT a bag of poop! (Seriously, it’s not.)

It’s a question we’ve heard countless times—for decades. There’s an obvious reason for the misunderstanding: Milorganite is the end result of Milwaukee’s sewerage treatment process. So, in the same sentence, you hear “sewerage” and “Milorganite.” People are bound to be confused.

So, if Milorganite isn’t poop in a bag, exactly what is it? It’s a bag of heat-dried microbes. That doesn’t sound much better, does it? Well, that’s what it is.

There are several natural steps Milwaukee’s wastewater goes through to produce clean water and Milorganite. Obviously, wastewater contains poop, and that’s what the microbes eat. It’s nature’s way of recycling.

Here are the basic steps that recycle poop into Milorganite.

  • Wastewater flows in, including poop.
  • The stuff microbes can’t eat is removed, such as plastic, shopping bags, sand, twigs, and other things that never should have been in there to begin with.
  • Microbes are added to the nutrient-rich wastewater. Yep, the poop provides the nutrients.
  • Microbes eat the nutrients.
  • When there’s no food left, they die of starvation and settle to the bottom of the tank.
  • Water is squeezed out of the mass of microbes.
  • Clean water is pumped back into Lake Michigan.
  • The microbes are dried in a really, really hot kiln.
  • Voile! It’s now pellets of poop-free, dead microbes. It’s Milorganite!
  • Milorganite is analyzed for at least 20 parameters every day to comply with all applicable safety guidelines.

So, the next time someone says, “Milorganite is a bag of poop!” you’ll be able to set them straight. It’s a bag of microbes that ate well, died and were dried.