Home biogas system- (part two)

It’s finally warm enough to start setting up our biogas system. A few weeks ago we got one of our neighbors down to help us level a pad for the unit and we gathered together all the bits and pieces we needed to set up the first part of the unit (the digester and gas collector part), we will set up the cooker that came with the unit once it is producing gas. The toilet attachment will be installed as part three of this project as we have to wait until the unit is active before we add human manure to the mix.

The unit will be to the North of the humpy, close to the kitchen and right beside the toilet. That way the gas does not have to travel far and neither does the poop.

Thanks for the help Louise.
A nice level pad for our biogas unit.

Next we laid down a ute mat made of rubber to protect the digester from any sharp stones that might be in the soil. The unit came with it’s own rubber mat, but we wanted to be sure it was protected. The extra rubber also insulates the unit from the cold soil a little.

Then it was time to put the pieces together and set up the unit itself. There is a really handy app that talks you through the whole process.

It looks like putting up a tent.
Can you believe the kit also includes a tiny tub of Vasoline to use as a lubricant for putting the puzzle pieces together?
There is even a little bucket to use as a measure when filling the sand bags (provided).

Filling the unit with water felt like a real achievement after all the brain work of putting the jig saw together. While it was filling up we got busy filling up the sand bags that become weights for the gas collector (the unit uses these weights to put the gas under low pressure so it is pushed through the gas line to the stove).

Filling with water took all afternoon.

The following sequence of photos show fairly clearly how to fill and seal the bags so there is not much air in them. This is important as the pockets the bags go into are quite narrow and the bags have to be squeezed into them.

The gas collecting bag is strapped onto the top of the digester then the gas and inlet lines are attached.
As the sun sinks rapidly into the West, we begin to fill the unit with cow manure.
A total of 3 feed bags of cow manure went into the unit tonight, we will add more over the next week.

The unit will begin to bubble and produce methane over the next few weeks and we will add the gas line and the toilet as part of the next stage. Look out for the next installment in a fortnight…

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Home Biogas system – a BIG step forward (part one)

We have been trying very hard to move away from using gas to sustain our daily life. We have historically used gas for running the fridge and for cooking and heating water on the gas stove. Recently we have upgraded our gas fridge to an electric fridge (solar powered) and now we are adding a biogas unit to the mix. This means that we will no longer have to buy gas bottles (yay!!), this is the final step away from using bottled gas.

Bottled gas or LPG (Liquid Petroleum Gas) is produced during oil refining and given the temporary nature of our supply of oil on this planet, we need to be looking at ways to move away from our reliance on it (not to mention the huge environmental cost of using it). LPG contains propane in Australia, in other countries LPG can be a mix of propane and butane.

Biogas captures methane and carbon dioxide (methane mostly) as a result of decomposition of organic matter. That is why the discovery of methane on Mars was such an exciting thing; where there are dead things there were once live things (usually, although not always and probably not in this case). I became interested in biogas many years ago (after watching an episode of The Good Life) and decided to work towards setting it up in our humpy. The idea that we could use our waste (of all descriptions) to generate some of our energy needs was very exciting.

The idea has been sitting on a dusty shelf at the back of my mind for years. Other, more attainable, goals have been on the work table of my mind. Six months ago (approximately) I stumbled upon a post advertising a biogas system designed for home use and the idea suddenly moved to the front of my mind again.

We eventually decided to go with a Home Biogas unit from Quality Solar and Plumbing

They are the only company selling these units in Australia and they are relatively close to us (only about three hours drive way). We saved up (in tiny increments) and finally, with a windfall of back pay, we ordered the unit. We also managed to add a toilet unit to the order. As soon as this unit is set up we can start to generate our own cooking gas (although the Year three student who lives in my head can’t help making jokes about cooking with farts).

As soon as the order was placed we realised we needed a site for the future toilet/gas generation unit. Then we need a shed or some kind of building to house the toilet and a pad for the gas unit to sit on.

A gratuitous ocean shot from our long journey to Mullumbimby to pick up our biogas system.

The first part of our biogas adventure was picking it up and touring a working unit while we were there. The very helpful Brian at Quality Solar and Plumbing gave us a tour of the biogas unit he has set up at his house.

This is the working unit. It was really exciting to see one working.
You put the food scraps or animal manure into the black pipe at this end…
and gas and fertiliser come out this end. How amazing is that?
This is the stove unit that comes with the kit. There is no smell at all to the gas and this burner obviously gets a lot of use.

We have our unit home. It is sitting in it’s two little boxes, waiting for us to make it a home and set up the toilet. I can’t wait to get it going.

The two boxes in the car constitute the entire kit. I was amazed at the small size of the whole thing and how light it was to haul around. It will be much heavier once the bottom of the digester is full of water.

The kit is supposed to include everything we need to put it all together. We will see…

At last…the new toilet is operational

I finally decided to stop digging the toilet pit ‘just a little bit deeper’and put it together. With the help of the whole family, we dug a final two wheel barrows of soil out of the pit, making the hole 1.5 cubic metres in size. Then my long suffering partner and daughters put the pedestal part together and bolted the whole lot to the floor.

The new pedestal on the floor. The floor is in two pieces and is not fixed, so it can be opened if the pit ever needs to be emptied.

The inside of the pedestal; The square inner lining is made from two old buckets with the bottoms cut out. This inner lining extends down through the floor and can be cleaned easily. The outer pedestal is a steel drum with the top and bottom cut out.

A flash new toilet seat bolted onto the pedestal completes the set up.

We put up the movable toilet tent over the whole thing for now.

So now the experiment begins, I hope this system works and we don’t have to do this all over again.

The toilet building itself comes next, but that’s another story.

Pit toilet update

At last we have restarted work on the long planned five star pit toilet. It has become increasingly urgent for us to have a new toilet hole (the old one is getting uncomfortably near the end of it’s usefulness).
Over the previous month or so we have all had a go at digging the pit deeper and wider, and it is almost deep enough at last. Today my (fairly reluctant) partner and eldest daughter were chased outside to begin building the framing for cement frame that will support the floor over the pit. Once the cementing is completed we will lay the floor over the pit (two sheets of really thick ply wood with a hole drilled in one), organize a pedestal (of some sort), put up a temporary shelter and it will be usable. The building part will be put together over the next six months or so.

The start of the frame for cement ‘stem walls’ to hold the floor up above the moisture and stuff.

The finished frame work, ready for cement.

The two sheets of ply for the floor, 

Nothing to do with toilets, but our baby guinea fowls have grown up enough to be out in the yard with their mum.

Everyone watches the cement mixer go around and around and around and…

Six or seven mixes later.

It’s almost full.

Smoothing out the top.

All done.

Roady (the butcher bird) fancies himself a building inspector.

Last minute touch ups after the dogs and sheep have inspected the work.

We admire our work as the sun goes down.

The next stage is to dig some more out of the pit (the deeper the better) and to  begin the building of the toilet. I look forward to it.

Just updating this post with a photo or two of the recent digging.

The hole is now 1.4 x 0.8 x 0.9 m; a tiny bit over one cubic metre of hole (I think)

My eldest daughter busily scooping out gravelly soil.

Short drop toilets

This may be a bit of a taboo subject in polite society…but it is a very important subject for those of us who choose to be responsible for as much of our own lives as possible; toilet designs.
Until recently I have been happy using a short-drop toilet design on our block; this consists of a vase shaped hole about 1.25 meters deep, 60 cm wide at the bottom and tapering to about 40 cm wide at the top. On top of this pit is placed a movable pedestal made from half a plastic live barrel with a toilet seat bolted on top. A tarp stretched over a poly pipe hoop frame completes the set up. We ‘flush’ by sprinkling a can of lime over the contents to lower the pH and make the contents more worm friendly and less fly friendly. This kind of toilet means that I have to dig a new hole every school holidays.

Lately I have been experimenting with adding compost worms to the mix. Once a new hole is dug and in use for a week or so, I tip in one container of compost worms from the worm farm at school. This makes the hole last roughly twice as long as previously; presently 20 weeks is the record. This means I have to dig less and can avoid the deconstructing and reconstructing of the toilet for a bit longer.

My new plan consists of digging a big enough pit to hold a year’s worth of…well….contents, and adding worms to that. I am hoping this will allow enough time for the worms to reduce the contents to worm castings and baby worms, which will then burrow away to seek a new life in a far off place, thus keeping the pit level to an acceptable level permanently (or at least a very long time). Then I can build a more permanent and attractive structure over the top of the pit.

According to the World Health Organisation Pit Latrine Designs, when digging a pit toilet you should allow  0.06 m3 per person per year. In our house that equates to (0.06 x 4 = 0.24 m3) to allow for visitor usage as well. This isn’t a huge hole really. I have calculated this to be about the size of a 240 liter fridge.

I am currently digging away at the pit for this toilet and will post more photos as I get to each stage. The ground is very hard at the moment due to the dry weather so going is slow. The next question will be “What do I build the toilet shed out of?”

Do you take responsibility for your own waste?
Would you like to?
Any ideas or comments welcome.