Dog Waste Digester Bin





Introduction: Dog Waste Digester Bin

Having a dog and little kids means there is a lot of dog poo to be picked up to keep the yard clean and the kids safe from illness and parasites. I decided to use an old HDPE barrel to build a dog waste digester.  I'll place the dog poo in the digester and add bacteria from time to time to break the waste down.  Much like a home's septic system.

Step 1: 55 Gallon Barrel

I started with an old 55 gallon HDPE barrel.  This one used to have soy sauce in it.  It was also used as a rain barrel and compost bin, so it's dirty inside, but it won't matter.

Step 2: Marking Door

I marked out the size of the door I wanted using to "L" squares to make sure it was true. It needed to be big enough that a shovel dropping in waste wouldn't make a mess on the rim and also to fit a shovel in case I ever needed to clean it out. 

Then I tried drilling small diameter holes in a row to make a slot in one corner to start the jig saw. I ended up snapping off the little drill bit so that ended that method. 

I stepped back and thought about it and went and grabbed a BBQ lighter.  I decided I'd try to heat up the blade until it would slide into the barrel. It worked like a charm.  I didn't even have to get the blade red hot.

After I finished cutting the door out, I used the box knife to clean the rough edges.

Step 3: Cut the Barrel in Half

Next I needed to cut the barrel in half.  I'm saving the other end for another project I have in mind.

The barrel has several ribs so I just measured halfway between them and marked every so often.

Then I took some wide masking tape and wrapped it around the barrel to give myself a guide.

I heated the blade again and plunged it in. I rotated the barrel as I cut.

It cut great and both ends came out super square.

Step 4: Attach Door Hardware

To finish off the door I used:

Two small hinges
A door clasp
2 plates to keep the door from falling inward.
3/16" Aluminum pop rivets
Stainless steel washers

I used some thin aluminum scrap pieces and clamps I had laying around to keep the door flush with the barrel, and also serve as centering shims.

I drilled the holes for the hinges and pop riveted them on with stainless steel washers on the back side to spread the load and prevent them from pulling through.

Next I attached the door clasp so I have a way to keep it closed so the kids and animals don't get into it.

Lastly I cut and drilled holes in two pieces of aluminum flat stock to serve as door stops so the lid doesn't fall inside.  I riveted them on with pop rivets and washers as well.

Step 5: Install

The finished project.

Notice the washers on the underside.

The last step is to find a location away from the house to dig a hole and bury the digester up to the top of the lid.

Once it has some waste in it, I'll add some bacteria sold specifically for the purpose of breaking down the waste.



  • Stick It! Contest

    Stick It! Contest
  • Creative Misuse Contest

    Creative Misuse Contest
  • Backpack Challenge

    Backpack Challenge

46 Discussions

I've got a 125lb Rott & a110lb Weim & I built mine over 2 years ago & it's never been more than 1/2 full. So I think U would call that a successful system. (With 235lb of total Dog-You'll be fine with your big guy)

It's hard to say. If you live in a warmer climate and keep adding septic tank bacteria and some water, it could probably handle it. I live in Alaska, so the bacteria take a long time to do their thing.

Thanks for posting! We need this with two large dogs. I have two small mischievous boys, recommendations for how to keep them from getting into this thing???

1 reply

Put a lock and latch on the lid and keep the key on your keyring

I used a circular saw to make the long parts of the cuts, then used my saber saw to square the cuts. I used a black poly barrel to begin with, made my cuts, buried it two feet in the ground and then made a box that I filled with insulation foam, and made a trap door to pull out to fill it. I put more than just doggy doo in it, I have 7 dogs and that means lots of poop. I put earthworms in along with eggshell and bones and scraps. I added a way to keep it damp by using the same hookup you would for a watercooler A/C. Just turn the valve, and let it rain inside the barrel for 10 minutes. I done this with 3 of them 4 years ago, and my first batch of compost smelt like the fertilizer you buy. Garden grows great! Going to upgrade my system sometime next year.

Isn't a septic tank more of a closed system? Wouldn't the fact that the poop and bacteria is exposed to the ground still leak the chemicals from the dog waste? Would love to hear an update on this one

5 replies

Septic tanks are open systems that leach into the ground through the leach field as the last step of the process. This digester worked okay. We have cold temperatures most of the year up here so the microbial action is pretty slow. It lasted for 5 years but was probably getting close to needing to be relocated to another spot.

Like with the use of these barrels as a composter, you could paint the thing black and or give the barrel that is exposed to the air some insulation to keep the heat created by decomp contained.

True, most of mine was buried so it didn't get much sun exposure. Warmer ground temps would help a lot. The ground here freezes up to 3 feet deep each winter, so it's really cold for 6 months of the year.

I'm in Houston Texas so heat not a problem here... Ever!

Sorry I forgot a step! You need to buy a bucket of a "special mix" Specfically made for this type of system. They sell it on Amazon for $6-7 a bucket. You add a few tablespoons a week. This breaks it down. I try to post the name of it along with a photo.
Thanks, I hope that helped. Mine has been working great!

Now if you can just train your dogs to raise up the lid and poop in the buried barrel...................LOL

1 reply

WOW. what a discuss. I will keep my dog poo and cat poo separate from my veggies thank uou. but I do love the simple design with flexibility in size. good instructable, crazy back & forth...

1 reply

So, how did this turn out? It's a great idea but I'm curious about how it looked after you buried it, what bacteria you purchased and how you use it / like it now?

This is such a great idea.

I purchased a system like this 25 years ago from a pet-store & paid $90 I
recalled the basic design & did a quick search & found this design. I was able to find a 1/2 size barrel that was perfect for this job. Cost me $10 & has a dome shaped removable lid that I can put over top of the hatch door for a nicer Aesthetic for the yard. Very pleased that I now have a place for my two 115 pound dogs poo!!!

This is great. I'm going to take this discussion thread and start from there. Lots of good information here. I really like what was said. Helps loads!

The rights and wrongs of China and Germany trading waste etc; is a worry to me, as China wants to export market garden produce and fruit, and in Australia, traces of human feaces have been found in some of those foods imported from China. I live in South Australia, and we treat our sewerage water, then pump it to holding tanks in market gardens, where it is perfectly safe for use. However, to the device above. I would make another alongside of this one you have, and add composting worms to it. There are a good few varieties, so add them all, and you may find that they soon demolish a pile of animal waste. The only time not to use the worms would be after the animals have had a worming treatment period. Dig a hole deep under the drum, and add chunky gravel and stones, a few litres of fresh rain water each week, and then the worms can escape to the depths in hotter weather.