biogas

A banana circle/transpiration pit hybrid

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The photo below may not seem like much, but it is a HUGE leap forward for us. Please excuse the finger in the shot, I was in a hurry to get back to filling the trench. This photo represents a change in our water harvesting and disposal system.

Previously, our waste water from the kitchen ran out of the humpy into a trench in the soil and was allowed to spread out randomly from there. You can see the big clump of iris and weeds against the wall of the humpy which marks the start of the previous trench. This system created a mess of muddy trench and water sitting on the surface of the soil. I put in a lot of work, with help from family and friends, to dig a drain trench and put in some actual plumbing. While I was at it, I dug a trench for the effluent from the biogas unit too. This effluent previously went to a transpiration pit near the unit, but I wanted to extend the pit, so decided to plumb all our kitchen and biogas overflow into a banana circle.

What is a banana circle? It is a hole with bananas and other useful plants growing around the edge. Banana circles usually have a water source and the centre is used as a compost pile. This provides nutrients and water to the hungry crops and makes a little island of fertility.

Below you can see the beginning of my banana circle. The plumbing is in and I have dug a hole about a metre deep in the centre and piled the soil up around the edge. My circle is in a low place in the yard, so it will also channel rain water into it. Because it is being used as a transpiration pit, I was careful to dig the hole deep enough to (hopefully) prevent overflow during rain events.

I piled logs and sticks into the hole to provide something to soak up all that water and nutrient and hold it in dry times. I also added a layer of compost over the trench to give the bananas a fighting chance. I edged the piles with big pieces of branch to make an edge to mow against and to hold in the compost and mulch.

I planted my banana suckers (only two so far), some cassava cuttings and about 100 comfrey roots. Then I started to trim and weed the garden and pile up the centre of my circle. I will continue to pile up cuttings and garden scraps in the middle of the circle. The water in the pit should be covered by material at all times, so it will be a race to keep enough composting material in there as it breaks down (it might encourage me to weed more).

This little project has solved a problem (sloppy trench through the yard) and provided a place to grow food and medicine (bananas, cassava and comfrey). It also used up one pile of sticks and wood from the sheep paddock that needed to be cleared. I am very satisfied with my results on this project.

Building a toilet – a new biogas unit

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Some time ago our biogas collector tank… burst. It was a smelly and distressing event. The tank had developed a small hole in the corner and the leak burst in a rush one afternoon. The smell was unbelievable, for an hour or so. The miracle of anaerobic digestion means that the digested material left in the tank, really didn’t smell once it was exposed to the air. Our lawn was very green for a long time too.

We hosed the liquid in to the lawn well and avoided the entire area for a week or so. We had to drag the old unit out of the yard using the farm ute, and bury it in a hole in the bush. I emailed the company and reported the incident and they emailed back with an explanation; apparently some of the tanks were stitched with a non-UV resistant thread, which would give out over time. They replaced the unit (for free) and we decided to upgrade the toilet situation.

My tired and reluctant partner built a toilet shed from scraps of metal and tin we had laying around. It took three days to build and is a lovely addition to the humpy (although it is square and has no lopsided walls, so it looks out of place).

We then dug out a level pad for the biogas unit, a piece of carpet supplied by a friend was laid out as a base and the tank was assembled and filled.

Then came the long and tedious wait for the unit to activate. I added horse manure and cow manure to the water and… waited. After a month or so, the biogas began to do it’s thing and we now have an active unit.

You may ask what we were doing for a toilet while this building was going on. We used the toilet as usual, but it fed into a bucket that was emptied every few days into a hole in the bush (then covered in soil). We soon grew tired of carting a bucket of poop into the bush and waited for the unit to activate eagerly.

Now it is time to upgrade the transpiration pit.

Home Biogas system- changing the filters

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Recently the biogas started to smell a bit, it had the particular odour of sewage when the burner was lit. This is not what you want to smell when you put the kettle on for your morning coffee. The smell means it is time to change the gas filter, luckily I had ordered a kit months ago. The gas filter is a plastic pot filled with activated charcoal, the pot has holes in the top and the sides so gas can travel through it. A rubber seal around the pot makes sure the gas has no option but to travel through the charcoal filter. They are fairly easy to change, having been designed that way, but there are some important things to note when doing this routine maintenance.

All you really need to do when changing the gas filter is;

  1. remove the stickers from the new filter canister.
  2. lever the lid of the gas collection pipe up until you can open it.
  3. pull out the old gas filter using the handy rope handle.
  4. place the new filter in the gas collection pipe.
  5. replace the lid of the gas collection pipe.
  6. open the old filter and add the charcoal to the compost pile or the worm farm.

However… I made several mistakes that led to us having no gas for several days and smelled fairly bad too.

My first mistake was not looking to see which way up the rubber seal on the gas collection pipe lid went. In fact I mistakenly threw the seal out as I thought it was from the old canister at first. This seal stops the filtered gas from escaping into the atmosphere, so it’s pretty important. The seal is contoured, so it needs to face the right way.

My second mistake was to try changing the filter when the balloon was full of gas. Nobody wanted to use the burner because of the smell, so the balloon was very full of lovely methane (and sulphur compounds). I levered off the gas collection pipe lid and got a face full of smelly gas as the balloon deflated entirely.

Other than those two mistakes, the whole process is fairly easy and no fuss. Next time I will change the filter as soon as I get a tiny whiff of smell and make sure to use all the gas before I change it. I wish I had taken photos of which way the seal goes in the lid, but I didn’t. Instead I took a screen shot from the assembly app to remind myself which way the rubber seal goes.

This system is so easy to assemble and maintain that I wonder why everyone doesn’t have one. It needs a little bit of maintaining now and then, but what system doesn’t? The benefits far outweigh the inconvenience.

The toilet is going to need a new water pump seal soon and the chlorine filter for the effluent needs replacing too, I am hoping those go as easily (but with less mistakes) as the gas filter change.

#coronavirus- sewing family cloths

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TMI WARNING; In this post I will be talking about toilets and what goes into them. If you can’t talk poop…read another post.

When I started using the camping bidet (henceforth known as the bidet) instead of toilet paper, one thing I was not happy about was the wet and dripping behind. While it is a small thing to deal with in the face of a global pandemic it is slightly uncomfortable. As usual, I turned to the internet to research a work around. I had considered family cloths as an answer to the toilet paper problem, and decided they were too much work; with soaking and rinsing and individual washing, not to mention the smells (of which we have enough already). However, using family cloths to dry the bottom area after a good hosing with the bidet, that seemed to be an easily implemented answer.

From what I have read, it seems that all I need is some relatively soft fabric, capable of absorbing fluid and preferably made from a natural fibre. I looked through my fabric stash and found a likely candidate… an old flannelette sheet. I cut out some smallish squares (15cm X 15cm) and overlocked the edges to prevent fraying.

I have a few old sheets in my stash. They are so useful.
Using a quilting board to cut out my squares.
My pile of 40 or so family cloths.
Darby goose looks on curiously.
A big pile of overlocked squares, ready to be used.

Next I found a container to hold the clean ones in the toilet and a bin and cloth bag to hold the used ones until wash day. The cloths will be washed with the underwear in a warm wash with soap nuts and lime essential oil.

The cloths are on the left in that little container, it holds 30 squares. The toilet paper is for my partner to use (and visitors…eventually).
The basket for collecting the used cloths. the toilet is in one of those camping shower tent things, so the hanging pockets come in handy here.

This little project couldn’t have been any easier. Within an hour I felt like I had solved the problem. This is one easy way to solve the wet bottom problem.

#coronavirus- swapping to a bidet

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The camping bidet in it’s neat little bag

The whole toilet paper panic buying thing has largely passed us by; we buy in bulk as a rule. We buy the WhoGivesACrap brand of toilet paper, by the carton. We still have 20 rolls left and we use about 1 roll per week. However in a bid to reduce our usage (and maybe stop using it altogether) I decided it was time to give the bidet a try.

TMI WARNING; If you are easily disgusted or offended, please go read another post.

The idea that we may not be able to buy more toilet paper when we need it (although not very likely) gave me the inspiration to look at alternatives. I researched family cloths, and decided that they are just a bit too much work for me (and it would be me dealing with it). As I browsed through lists of plants that can be grown to provide toilet paper alternatives I realised that I needed to plant them two years ago to be able to use them now. Eventually, I came across references to the bidet and camping bidet in particular.

Since we put in the biogas toilet we have been using recycled toilet paper as it breaks down faster than other kinds. Too much paper in the system can slow down the methane production and even clog up the pipes (to be avoided at all costs). Paper is also very carbon rich, it doesn’t produce as much methane as nitrogen rich material (like poop); so we want to minimise paper input.

The biogas toilet in it’s little tent
The biogas unit, chugging away making methane for our cooking

I looked around at all the bidet units available, some of them use electricity or need to be connected to pressurised water inlets (neither of which we have available). Eventually, I found the whole range of hand held, portable bidet units (and ordered them online). They are sold as ‘camping’ bidet; we have quite a few ‘camping’ options in daily use in the humpy.

This is the actual unit; the spout is telescoping so it will fit nicely into the provided bag (which I don’t need for home use)

The camping bidet is essentially a water bottle with an angled spout. You fill up the bottle (which has a valve in the bottom so it doesn’t lose pressure as it empties), then use it to wash your bottom clean instead of wiping with paper.

I was nervous that the water wouldn’t clean everything off and that I would be left with an uncomfortably wet bottom even if it worked. The first use was a pleasant surprise; The bottle, even though fairly small, was enough to clean everything very well (and I have a lot of ‘everything’). The water was not uncomfortably cold, and the pressure created by the bottle and spout was like a mini high-pressure cleaner on the offending body parts.

Please excuse the sound in this video; I can’t seem to turn it off.

The only problem I am left with is a wet and dripping nether region; to answer this I decided to sew up some family cloths, which will be used to dry the area only. This means that there will be no more poop, pee and other nasties on the cloths than there is on our underwear and towels. That way I can wash the cloths in the same load as underwear.

The obvious problem of increased water use also needed to be thought through. As it has been raining fairly well since the end of the fires, we don’t have to be worried about water use at present; hoever, when the rain stops again (and it will) we will have to re-assess. One up-side of the extra water use is that I don’t have to top up the toilet flush bucket as often because the water in the bidet is enough to flush the toilet with. The water in the bidet is fresh though, while the water in the flush bucket is recycled (collected from the kitchen sink from hand washing, vegetable washing, unfinished water bottles tipped out, etc).

The end result is that I love the camping bidet, it leaves me feeling like I just had a shower, it reduces my workload (slightly) and reduces the bulk of material going into the biogas system. My partner however, doesn’t want to try it. He is set in his ways and doesn’t like new things… I will keep trying to convince him.

Home Biogas system- part four- the mulch pit

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Since the toilet is up and running, we need to get the mulch pit finished. At the moment it is hard to concentrate on any project. The constant threat of fire and the despair that comes with knowing that so much of our ecosystem is destroyed keeps us in a constant state of depression. It is hard to concentrate on anything except watching the media releases about the fires all over Australia. However, it is important to keep working towards the future we want; how else will we reach it? In between the fire threats and increadibly hot days we made a plan that involved digging a pit to drain the effluent into then covering the lot with gravel, wood chip, soil and mulch.

The biogas system continues to impress me, the only down side I have discovered is the flammable nature of methane (which is kind of the point) and the fact that we can’t move the unit away from the house in the event of a bushfire threat (we are at a count of three direct threat situations so far in the last twelve months). We have countered this by releasing the methane into the atmosphere when there is any risk of fire. There is a handy tap that allows the gas to be vented easily. The refill time is getting less every day; currently the tank will fill in about ten hours and the effluent has proven fairly easy to bucket into the old toilet pit on a weekly basis.

Since the effluent is from human poop, it needs to be handled carefully. The effluent is passed through a chlorine chamber before it emerges from the unit. Treatment with chlorine is the accepted way to treat human effluent, it kills off a lot of nasties and oxygenation and exposure to sun takes care of the rest. After it emerges from the unit our effluent goes into a bucket, which is then emptied into the old toilet pit (which helps the waste in this pit continue to decompose). It is time to put in a hands free option for handling the effluent. In our situation we have several options; we could feed it into our septic system (except we don’t have one), we could build a dedicated transpiration pit or we could build a mulch basin. We went with a combination of the transpiration pit and the mulch pit ideas.

Effluent pitDownload

First we (and by ‘we’ I mean my hard working partner) dug a pit that was about 40cm deep.

I took this photo after we had begun to fill the bottom with gravel.

Then we put in a layer of gravel in the bottom. This layer is about 5cm deep. The plumbing part of the project was then completed before the pit could be filled up all the way.

Next step was adding a straw layer to slow down the migration of soil into the gravel.

After that there is a layer of wood chips (to soak up any nitrogen rich moisture that makes it that far) and a layer of soil to seal the pit off from the surface.

After that I planted the passionfruit vine I bought to (hopefully) take advantage of all that moisture and nutrient. I mulched around the vine, then realised that it is now a fire risk and would be raked away when the next fire threatens. To counter this a little, I buried the mulch under a deep layer of soil again. I hope this will protect the mulch from ember attack in the event of a fire.

So now we have a new garden bed that doubles as a transpiration pit. Hopefully the roots of the passionfruit won’t bung up the draining system and hopefully the buried mulch will be safe from ember attack (I am thinking that this method might be good for the new vegetable beds when we get to that). We, like most of Australia, are still in shock from the magnitude of the fires this year. We fear that next year will be more of the same, so everything we do from now on needs to be focused on fire safety and how to keep our family safe.

Home Biogas system- part three- the toilet

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We finally got around to putting the toilet on the biogas system. Mostly because the old pit toilet is VERY full (no pictures), and I developed a tummy bug over the weekend. These two factors in combination drove me to push everyone to throw together at least a temporary fix for the increasingly urgent problem of the full pit toilet.

The inside of our new toilet. Only another humpy dweller is likely to understand just how exciting this moment actually is.

The pit toilet has been great for about five and a half years. It took a month to build, and it was a great relief to have it finished at the time. If you click the links, you can read all about that adventure. Since the worms seem to no longer be living in the pit, and there are very few flies around (a worry of a deeper kind), the pit has filled to the point of being in danger of over flowing. We never did get the toilet building built, instead we continued to replace the tarp stretched over the top on a yearly basis.

The new biogas toilet will have a similar privacy situation, and the plan is to build a solid structure over it (but given our past experience, I don’t know when/if that will happen). The kit came with almost everything we needed, so instead of taking a month of labor (on and off) to build, it took me a frantic two hours (and a bit of help with lifting and drilling) to put the basics together.

First, I found a solid pallet in the useful pile in the sheep pen. This pallet will need to be replaced fairly soon as it is not made from hardwood, but it serves the purpose for the moment. The pedestal is bolted onto it using four roofing screws and another piece of timber under the screw holes to give it a bit of security. The pedestal feels solid and reliable, and the extra height brings it up to the western conventional position.

The temporary bucket set up
The kit even has a filter for the flush water.

Secondly, the flush side of the plumbing was set up. I just pushed the inlet hoses onto the inlet spout on the toilet and put the filter on the pipe, then dropped the free end into an old bucket (with water in it). The bucket holds some precious second use water from the sink where we wash our hands. Usually we use this water on the garden, but we are forced to put some of it through the biogas system now.

You can clearly see the hose connections in this photo
The outlet hose goes into the biogas unit. There is about 2 metres of hose inside the unit to be sure the poop is delivered to the bottom of the bacteria colony.

The last step is to connect the outlet pipe to the toilet and feed about two metres of pipe into the unit to be sure the poop goes where it needs to go; to the bottom of the unit where the most bacteria live.

The toilet is operated by setting a switch to either a 1 or a 2 (I figured out that this is 1 for pee or 2 for poop) and pumping the handle up and down until everything goes away. It is comfortable and easy to use.

The effluent currently flows into the white tub and is used on the garden, but now there will be human effluent rather than just horse poop going into it that will need to change.

My next job is to connect the effluent pipe to a transpiration or mulch pit. Since we have been using only horse and occasionally dog poop in the unit (along with some food scraps) and the effluent is filtered through a chlorine tablet, I have been using it on the garden to feed all my plants. Now the human poop element has been added, I will have to divert the effluent to a mulch pit or another underground absorption situation. The tummy bug that made this job so urgent also means that I am introducing some not so human friendly bacteria into the unit and I don’t want to risk those bugs getting loose among the other humans of the house. Since my fairly useful partner is in town getting fittings for this phase of the job, I will make that the subject of another post.

The biogas situation at the moment is wonderful; I feed the unit about half a bucket of horse manure and any food scraps or dog poop I collect through the day (most food scraps go to the chooks though) and we can burn the methane for about two hours a day. I expect to get better gas once we are feeding the unit fresh manure (ours) rather than days old horse poop.

Biogas system update

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I realise I should have posted about how the biogas system is working a while ago, but…better late than never.

The system took a while to produce gas, it sat for weeks looking sad and deflated, even though I fed it a bucket of horse manure every day for the first week.

Eventually the weather got warm enough and the microbes in the tank woke up and started to feed. The gas holder slowly filled up until it was just over half full. I really wanted to try out the burner to see if we have methane in the tank or just carbon dioxide (which is apparently common in the first few months).

We connected the gas line to the stove that came with the kit as soon as the gas holding…balloon? (I’m not sure what to call the thing that holds the gas) got to almost full.

The gas balloon about half full.
The gas line connected and running through PVC pipe to the house.
The gas line into the house.
This is the cute little burner that came with the kit.

The first lighting of the flame ; this was a momentous occasion. We lit the flame and it just hissed at us for a few seconds, then an almost invisible blue flame was born. We boiled the kettle for the washing up in about 5 minutes and celebrated with a coffee…then I made soy milk…and my daughter made a stew…and so on.

Our first water boil using biogas. The flame is almost invisible.

The gas balloon went down a lot in that first afternoon as we used the burner constantly (that’s what you do with new toys isn’t it?). After that I went back to feeding the system a bucket of manure every day. The colder weather certainly slows down the gas production and we don’t have enough gas to use as our only supply just yet. Once the toilet is connected to the system the feeding of the digester will hopefully take care of itself.

I am sold on biogas; even though the initial set up of the bacterial colonies takes so long (especially in Winter) and the refill time is fairly long at first, the system works and is improving daily.

Home biogas system- (part two)

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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…