Anaerobic Digesters

[stevej37]

Our smaller city (6500) has had an anaerobic digester for a few years now. They are a great benefit to the food producing industries in the area (Gerbers) and the local farmers.
The 40 acres across from my home started using it yesteday. Semi tanker trucks lined up all day yesteday and today. I estimate 25-30 trucks each day. Each tanker truck holds 7500 gallons of the slurry. The green box trailer holds the slurry and pumps it thru a hose to the tractor in the field.



The tractor pulling the hose around the field and knifing in the slurry (that's my mailbox!)


There were usually three tankers in line all day unloading. Each tanker took about 10 minutes to unload.
Does it smell?....yes, but not when done because it's in the ground, not on it.

[masraum]

What's in the slurry? What refuse is digested?

[red-beard]

The final slurry from an A-D is no different than compost.

[red-beard]

Originally Posted by masraum

What's in the slurry? What refuse is digested?

Typically food waste. Out of date veggies.

[stevej37]

Originally Posted by masraum

What's in the slurry? What refuse is digested?

Mostly cast-off materials from vegetables and fruits that the producer would otherwise have to pay for removal.

[stevej37]

Originally Posted by red-beard

Typically food waste. Out of date veggies.

Yes, and they apply heat to the mixture to get it in the right form.

[masraum]

Originally Posted by red-beard

Typically food waste. Out of date veggies.

Got it.

Years ago, my mom worked at the commissary at Whiting field (tiny Navy base near Pensacola. Seahawk is probably familiar). My parents also had a garden and crap soil (all sand). For quite a while when the produce would go bad, she'd bring it home and put it in their compost pile. It made a huge difference for their garden, but they actually got much better veggies growing right out of the compost pile.

[stevej37]

Gerber feeds almost every baby in the country out of the plant here. Enormous amounts of fruits and veggies go through the place. Lots of waste products.

[stevej37]

There are no animal manures used in this anaerobic digester.
The nitrate level is closely watched....on the farms and in the digester.

[red-beard]

Originally Posted by masraum

Got it.

Years ago, my mom worked at the commissary at Whiting field (tiny Navy base near Pensacola. Seahawk is probably familiar). My parents also had a garden and crap soil (all sand). For quite a while when the produce would go bad, she'd bring it home and put it in their compost pile. It made a huge difference for their garden, but they actually got much better veggies growing right out of the compost pile.

First, an anerobic digester means "without oxygen". A compost pile is an aerobic digester. When you decompose organics without air, you produce methane and carbon dioxide. Composting produces only CO2 and lots of heat.

With an anaerobic digester, you get the energy as methane instead of heat. After dewatering the material from either process is the same.

My main business is Landfill Gas (anerobic) to Energy. We also do A-D for food waste diversion. And we also take the A-D gasses from waste water treatment plants.

[Evans, Marv]

red-beard. You're involved in so many cool things. You definitely should run for President with such a pool of knowledge.