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.