Poop piki piki for my biogas system

Piki piki means motorbike in Kiswahili

This gadget was created to solve a real problem with biogas – getting the dung to the system quickly and efficiently. Motorbikes are the taxi’s of Africa so why not? Before I tell you about the above gadget I just want to remind you about the problems we have been having to solve to get the biogas to work at home.

Installing biogas at home has a real experience in afrigadget – we have figured out by trial and error how to get the gas under pressure –

At first we tried using water pressure, but when we stepped back and looked at it we realized that it really wasn’t simple or appropriate for bush applications ..

In fact, all we needed to do was to put pressure on the bags.

The pressure wasn’t enough to run the stove until we modified the stove jets by enlarging them slightly.

Next we had to figure out how to get the dung to my digester – you see I don’t own cows but my neighbors who live a few kilometers away do and are selling it at a very nice rate of Ksh 50 (70 US cents) for two large buckets . The owners are happy to see the dung as it  accumulates in the nighttime stockades and attracts annoying flies that carry diseases if left on the land.

The problem I face is common to many folks around here, we rent houses  but we don’t have livestock. But there are huge cattle farms around us. So Dominic came up with a solution that creates jobs and moves poop quickly and efficiently.

So we went to the local juakali welder on the roadside to create a dungmobile ..a trailer designed specially for cow dung!

We tested it with a human load to ensure it is balanced … each bucket weighs about 50 kg.

And the first delivery arrived without a problem! 🙂  Big Thanks to Dominic Wanjihia who seems to always have a simple solution to any problem.

I know you are wondering, if it’s that easy, then why doesn’t everyone use biogas?

Now that I’ve got biogas running my kitchen I wonder why so few people have done so in Kenya. There are countless articles, publications, websites and people who will tell you that biogas is the most economical and environmentally sustainable way to produce energy. In fact, the benefits of Biogas have been known for tens of years, and hundreds of systems have been built in Kenya. But it hasn’t really taken off –  few of the installed systems are actually working and the uptake of biogas systems at a domestic level has been slower than slow – it’s virtually non-existent.  A review of biogas in Kenya reports that technical breakdowns has discouraged uptake but the main limiting factor is cost.

Here’s a simple comparison of costs – from continuing using charcoal/fuelwood or Kerosene and LPG to using various biogas options.

Options Cost (US$ ) Time to install (days) Labour Maintenance Durability
Fixed dome 1,500 – 2000 21 5 people Low Decades
Floating top 2,000 – 3,500 21 5 people Low Decades
Flexi bag envelope 400 1 1 person Low 10 – 15 years
Fuelwood  or LPG cylinders 200 (per year) 0 0 low Decades

For a simpleton like me these figures are immediately revealing – it takes 2 years to pay off a flexibag digester after which domestic fuel is free for at least the next 10 – 13 years. For the underground systems you have got to be  hugely rich, or suffering from environmental guilt to make the decision to switch to biogas – from an economic perspective it will take 10 to 20 years to pay back. You could grow your own trees and make your own charcoal  in that time frame….

Why is it so expensive for the constructed biogas systems? Because most of the biogas systems  in use are constructed systems requiring engineering and masonry, they are very expensive, take weeks to install, require experts, and intensive follow up. If they go wrong it’s a major engineering task to fix it. This is why we are promoting the flexible bag option for domestic and small industry use.

Congratulations to Skylink Award winning Kenyan  biogas innovators

We would ;like to congratulate Skylink Innovations who have just won a the Ashden 2010 Award for their biogas installations in Kenya.

Skylink recieve the Ashden Award from Sir Richard Attenborough

I thought skylink was an airline… Biogas operated planes???

Human waste digester under construction in Meru Prison

Their industrial scale system costs Ksh 1.6 million (US$ 19,753). Such installations may need to be financed by the Government institutions where they clearly make enormous economic and environmental sense for schools, prisons and other large institutions.

For small scale house hold units, we need solutions that will compete against the cost of installing LPG or using charcoal, firewood or kerosene stoves. When we talked to local Maasai near Nairobi they found the flexi bag systems appealing because they could be purchased with the sale of just 2 or 3 cows, can be rolled up and moved when they migrate, and it saves the women the work of searching for firewood, it’s hygenic because water can be heated for bathing children, while it also removes dangerous piles of rotting cow dung near the homesteads which are breeding sites for biting and disease carrying flies which affect livestock and people.

Solving the flexible biogas digester problems

You’d think that given the amount of cow dung available around rural Africa that biogas would be a big hit right? Well, its actually relatively unknown. The main reason is materials, coast and complicated technology. People in these areas use charcoal or wood for their domestic cooking needs – its not only dirty hard work to collect firewood, but it’s unhealthy and damages the environment. But, it’s free …

We believe that  biogas from cow dung holds huge promise for rural and urban areas as a cheap source of energy that can be turned into domestic use or even business anywhere in rural Kenya….eg. pasturizing milk, making yoghurt, running fridges, generators, hammer mills for grinding corn, cooking, baking, heating water, running machines… and reducing your carbon footprint.

I have recently become the latest guinea pig for Dominic Wanjihias experiments … and it has been quite a learning experience

Problem No. 1.The system needs to be cheap and mobile for communities who don’t own land or who move regularly (pastoralists)

Simply Logic flexi -bag for biogas - small, cheap and made of parts you can find in any hardware
Biogas system on a motorbike in Kenya
You may need a Dominic to help set it up
It can be dirty work - but don't let that discourage you...

After only 2 weeks it will have ballooned like this

After only 2 weeks the bag will have inflated with methane - beautiful biogas
Great party trick: The biogas will burn and amaze

Problem No. 2. The pressure is not enough to light a stove. Nothing ever works as you initially planned that’s why having a fundi like Dominic around to modify, adapt and rethink as you go along helps so much.

To create pressure Dominic got two tanks, and did some juakali pipe connections. One tank was placed above the other. The lower tank was filled with water. Long pipes and short pipes were put through the lids and specially made holes in the tanks …  It’s all about applying simple physics really…

You need a few tools - all available at tusky's or Nakumatt

Then using a pump ..(we’ll be using a modified bicycle pump next time) he was able to move the gas from the flexi bag to the lower tank and displace water to the upper tank. This water creates enough back pressure to get the stove to light.. that’s the theory … here is what happened.

A curious boda boda rider (motorbike taxi) called Victor volunteered to help… Rhoda watched in awe

Victor pumped... others set up the stove

“Houston we have a problem” …Ok, accidents are bound to happen…pressure pushed the pipe off  and Victor got soaked..just water though. The top tank fills with water as you pump biogas into the bottom tank, and the water drains back to the bottom tank as the gas is used

Course all this hard work was not for nothing – we had to make a cup of tea –

It took 15 minutes for the water to boil!

Yes we are very very proud that the system worked so Cheers! a well deserved cup of tea.

We estimate that it took about 1/4 to 1/2 of the gas in one blue tank to boil the kettle – that’s about 1/8th of a cubic meter – and the entire flexi bag contains about 5 cubic meters… which means we have about 10 hours of gas use…..and the stuff is being produced all the time (we had quite some wastage as we fooled around to get the system to work)

Well it all seemed to be going just fine when …pssssssttttt

Houston, we have another problem...we sprung a leak!

Nothing serious but we were losing a bit of gas through one of the lids (holes had been drilled through the  lids to insert pipes) …we  need to fix that before we build up any pressure in that tank.

If you are interested in biogas let us know! Leave a comment.

Building a (one-stage) Anaerobic Digester

David of the Kenyan Community Initiative Support (KCIS) recently built a very low tech Anaerobic digester using only a drum, a valve and some pipes:

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The balloon shows that gas is being produced. The costs for the drum and professional valves may already be too high for some, and the design isn’t that optimal. They intend to add a storage drum with a water-filled header tank for constant pressure and the loading & desludging processes obviously still require some work.

We still like the approach though, because it does indeed “prove the theory”, as David notes. The theory of building a rather small anaerobic digester that will even work with smaller amounts of organic waste.

Goes to show that producing methane gas from something which would otherwise remain unused (livestock faeces usually kept in such drums for a few weeks without harvesting the methane potential) still is an interesting alternative & well appreciated once costs are covered.

F-art

Recycled art at Kitengela
Recycled art at Kitengela

Anyone who has been to Kitengela Glass near Nairobi will instantly recognize the works of art made from recycled glass, metal and other materials. Stunning works by local artists support a huge community of people and beautify gardens, offices, institutions and homes. I bet you aren’t expecting me to talk about crap right? Wrong!

Kigengela art glass
Kigengela art glass

Creating art from recycled glass takes a huge amount of energy. The glass recycling factory produces tiles, windows and other items, fueling it with used oil, butane gas and electricity. But now they are exploring the use of human gas, yes that’s right – it sounds disgusting, smells disgusting, but what a wonderful source of energy!

Pig for poo
Pig for poo

Apart from the excrement from pigs, chickens, horses, donkeys, ostriches, ducks, and geese

human wastes are collected … in these loos designed to keep you intrigued…

Loo seat
Loo seat

and seated for long enough to be ‘productive’.

poo bus
poo bus

The wastes (no, not the human ones) are transported to the biogas production site in a specially designedloooong-armed wheelbarrow

Shit stirrer
Shit stirrer

where it is poured into this big pot, where it is stirred (not shaken) by a professional shit stirrer.

Fermentation
Fermentation

Then it flows to the fermentation pit to digest….

Fermentation  system
Fermentation system

Notice how the toilets are being constructed at the top end of the system. This allows the poo to flow directly into the first tank .. it flows by gravity to the fermentation tank and then a settling tank before the sludge flows out and down a drain into another holding tank out of the picture.

The gas is piped to the household kitchen and the glass art workshops,

while the waste sludge is extracted and used on the gardens, i.e. total recycling!

In addition the Kitengela Glass factory creates an odd assortment of jobs from artists to poop stirrers, farmers and  biogas producers… for more information read about Kitengela here.

Amazing isn’t it – The first example of Art from Fart