Wednesday, April 27, 2016

For when ya gotta go: I compost a blog entry here

We installed an Airhead composting toilet.

Fair warning...this will probably be the crappiest topic we discuss, and I will approach it with a rather pissy attitude.
Further, in an attempt to use as many euphemisms for peeing and pooping as I can possibly squeeze out, the introductory section may fail to meet the brevity standards of the aesthetics committee. In other words, I may be sitting on the pot too long before getting off.

Introductory section:
Practical RV toilets come in two flavors, chemical based black holding tank & cassette types, and composting types.

We early made the decision to try a composting unit. Several reasons.
All chemical systems  mix #1 and #2 with chemicals. The chemicals are there in a desperate attempt to control odors. These systems require emptying the resulting lumpy chemical stew at an RV disposal site.

We didn't want to deal with the complexity of building a black water holding tank system. Valves and roof vents and under chassis tank mounting. A pain in the ass to design and build into a one-off limited space camper. A waste of the limited supply of perfectly good drinking water to flush after you use your aforementioned ass for its intended purpose. Then you need to lug around the flavorful mix until you find a socially acceptable dump site.

Cassette systems are pretty much mini, removable black holding tanks built into the throne. They may have their own flushing water reservoir. Dumping still should be done at RV dump sites. You need to allow adequate space in the bathroom to maneuver the cassette tank in and out of the pedestal. Tank size is limited to how much you can lift or roll in and out of your RV. The holding tank is typically much smaller than a normal RV black tank. Maybe 5 gallons vs. 20 or more. Some cassette toilets are designed to remove that tank through a hole in an outer wall...not viable for Annie's design.

Once we eliminated black tank and other impractical options (for example, litterboxes, underwear, etc., have limited carrying capacity), we looked into composters. At least while they were empty, we liked what we saw.

Composters were designed to biodegrade waste into usable, non-toxic things like fertilizer. They come in 2 varieties: separating, and non-separating.

Non-separating units were #1 on the scene. They are typically quite large, and require significant ventilation control. Reason is that the stored organics are wet, the composting process is largely done by anaerobic bacteria, and the anaerobic byproducts include ammonia and other nasty smellies.

Separating units were dumped on the market as an improved way to address the size and odor issues. I'll leave it to the reader to conclude what gets separated from what.
They use  material like peat moss or coconut coir to mix with the solids, and along with some airflow through a vent, help dry them out. The chemical reactions are primarily aerobic, and (theoretically) almost odor free. Since this is also a drying process, the storage efficiency goes way up. The #1 design criteria for this to work is for one to divert #1 into its own bottle.

When the storage fills up, solids can be allowed to fully compost and eventually spread in places like flower gardens (NOT veggie beds). Or they can be plopped into a garbage bag and dumped into the trash. Liquids can be diluted and dispersed, like against a few friendly neighborhood trees, or just poured down a standard toilet.

To be clear, we have yet to actually use the composter.
All the reviews and discussions we've read indicate that a separating composter is the best choice for Annie's use.
Well, more accurately, for our use inside Annie. Annie doesn't have an independent biological digestive tract.
We will learn if this was a wise decision once it's too late.

Installing the toilet:
We're starting work on the bathroom. (walls, counter, sink, cabinetry, etc.)
The bathroom is a pretty small space.
We felt an urgent pressure to install the toilet now, to make sure that we had adequate clearance to move around, build the walls, etc. without finding out later that the toilet was unusable because of space issues. As I mentioned earlier, litter boxes were not a viable options.
Once the john was installed, it is easy to remove to do construction, and to put back if any space issues or questions arose.

There are two brands we considered: Air Head and Nature's Head. Both are probably very similar in capacity and effectiveness. We went with the Airhead for 2 space related reasons: the overall footprint is smaller, and it's possible to remove the pee bottle without needing to tilt back the main body. That means we can mount it closer to its rear wall.

Here is what the installed unit looks like:

First thing to do was establish the location. We had rigged up some cardboard as counter and door substitutes. Then we moved the AirHead around till we found the best position.
The unit is mounted by 4 floor flanges. (Say that fast 10 times.) Two for the main body, and 2 for the pee bottle

Marking the main body flange locations:

Next we located where the vent will go. We chose to vent through the floor, although wall or ceiling venting are also allowed. That way, with enough methane build-up under Annie, we can use a spark igniter to give a jet assist as we go over a large rock.

The bell shaped housing holds the exhaust fan. The gray pipe doohickey has an insect screen, and uses some of the supplied vent tube to screw into the bell.

Drilled the hole:

I made up a through the floor vent tube with some 1.25" sched40 and a bandsaw cut piece of 1.25" coupling.

Painted the hole from top and bottom, filled it and any gaps with Great Stuff, and dropped the tube in. Cut clearance for the flange out of the vinyl flooring, and glued the vent down with gorilla glue. Removed any of the Great Stuff from the inside of the tube. Added more Great Stuff at the underneath where the vent comes through the van body.

Wired in the fan, and screwed down the bell and (previously marked) toilet body flanges:

Installed the toilet and made sure that the vent hose fit properly:


Then, using the mounted toilet, attached the pee bottle and marked for the pee bottle flanges:

And completed the effort by removing the unit and flanges, just leaving the screws:
This is to prevent damage to the flanges as we complete building the john's walls.

I hope that you all are properly moved after reading this entry, and that it wasn't too hard going.