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.

MFA: Water bag design challenge!

Amy Smith (of MIT’s IDDS) somehow got a hold of a mic and madhouse has now ensued! Everyone has been split up by their birth month into groups. They are given 5 water bags (sachets) and told to solve the world’s greatest problems. 30 minutes later we get…

5 Bag challenge

January: The Sachet Kebab
Decreasing litter and polution. People can collect water sachets off the ground easily with a pole and spiked end. It can be placed along the roads, and a lot of trash can just be spiked on the tip of it.

February: Hydro Electric
Generate electricity by using the bags to create small turbines.

March: Light absorbent and heat absorbent bags
They also had a crazy idea of drinking the water, peeing in the bag and selling that to farmers for fertilizer… to much laughter…

April: Potting and a Wallet
Drink the water and make it empty. Cut the top off and put in soil and grow small plants. Take another bag and put a small hole in it for drip irrigation. Second idea: use the bag to put your money in for when it rains.

May: The individual water-shower packet and a purse
Hang the water and put a small hole in it. Create a purse out of it to hold a camera or mobile phone.

June: Waterbelt, glasses strings
They’ve created some really interesting spectacle (glasses) holder. Also, a waterbelt to hold the water as you’re moving around.

Maker Faire Africa: Ghana 2009

July: Water purifier
Uses the light from the sun to help purify the water. It takes a bottle top cut off and used as a funnel as well. It’s shaped like a train, for marketing reasons.

August: Kids toys
Make small airplanes and hats for children and an hourglass made from 2 water bags.

September: Drip irrigation and a pillow
Puncture a bottle or a bag on top to collect water, then use for drip irrigation. Also fill multiple old empty bags with air and put them inside a pillow case to create a pillow.

October: Drip irrigation
Starts with a bag, then a tube made of old empty bags that can direct the water further and over more areas.

November: Water resistant mobile phone case
“Your phone case is not water resistant, ours is. Clap for us.”
“We have created a water wallet, not just a plastic money carrier.”

December: Water sachet lighting system and a sachet wrist watch band
Put full bags on your roof that diffuses the light and warms the water.

Hacking an in-office shower

File this contribution from South Africa into the “odd, yet interesting file”:

“What to do when you have a bath tub, but actually want to take a shower? Easy, just use whatever office materials you can find to make your own shower. Find a long rod, balance it on top of a door and the burglar bars. Attach a sheet of plastic, using office clips. Voila, you have a shower curtain. Now we want to use both the cold and warm water taps, so using pipes and ropes to hold them in place, both sources are fed to the main pipe leading up to the shower head. The shower head is attached to a shelf bracket using oh-so-useful cable ties.”




Keyhole Gardens

Following a story on BBC News that fellow blogger Sokari of BlackLooks had already picked up earlier in June (as well as Alison), our reader Zeno dropped in an e-mail, asking if we knew more about keyhole gardens.

Keyhole gardens?

Actually, I had heard about those Folkewall installations in Gabarone, Botswana the other day that are used for greywater recycling, but keyhole gardens were indeed quite new to me. Guess this also shows how many smart solutions still exist out there that will need to be rediscovered and put in use.

source: African Gardens

Keyhole gardens are a technique used to grow vegetables in a dry climate. They are actually a special form of raised bed gardens: circular waist high raised beds with a path to the center. Walled in by stones, there’s a basket made from sticks and straw in the center that holds manure and other organic kitchen waste for compost.
Since they look like a keyhole from above, they are often called keyhole gardens and also promoted under this name in Lesotho, where the charity organisation “Send a Cow” has been promoting the creation of these special gardens for some time now.

So what makes these gardens so special?

  • the surrounding stones retain the rich soils and keep it safe from erosion
  • the round shape retains moisture
  • compact size, even small plots can be used for gardening
  • raised beds enable the sick and elderly to help with the gardening work
  • center in the middle is used for composting and reuse of greywater (= reuse of nutrients)

“Send a Cow” also created a very informative website on their activies and published some valuable How-to-manuals for us to adopt this smart approach. Please also check out this funny animation on YouTube which puts it in plain enligsh comic style 🙂

Now I am only curious to know if we could also mix the greywater with some collected urine and use that as additional fertilizer. In any case, keyhole gardens are a very appropriate “technology” which certainly isn’t limited to countries with a dry climate.

The VIP – an invention from Zimbabwe

Ingenuity, obviously, isn’t only limited to the African continent, as it is especially found in societies where access to resources is limited. While we’ve been able to witness lots of interesting innovations from other regions of the world that were born out of a lack of readily available solutions, we must also not forget that a few smart ideas were actually developed in Africa and have since then conquered the world.

One of such smart ideas is the Ventilated (Improved) Pit Latrine, in short: the VIP – which was developed as the “Blair Latrine” by Peter Morgan, who has been living and working in Zimbabwe for over 35 years, researching and developing water and sanitation technologies.

venting a pit latrine
Diagram showing effect of vent pipe on functions of pit latrine (source)

The major advantage of the VIP over a normal pit latrine is that it comes with a ventilation pipe (covered with a durable fly screen on top) which reduces flies and odour. In the absence of other alternatives, the Ventilated Pit Latrine is considered reliable, which explains the success of this technology: over 500.000+ units of this type have been built in Zimbabwe alone and it has proven to work elsewhere around the world.

The VIP clearly isn’t the solution to sustainable sanitation as it comes with a few limitations, but it does function without water and has very low investment, operation and maintenance costs.

Next to some interesting experiments with different water pump systems such as the Blair hand pump (also known as the Zimbabwe Bush Pump) or the spiral water wheel pump, Peter is also active in the field of ecological sanitation and recently published a very interesting booklet titled “Toilets That Make Compost” where he writes about his experiences with compost toilets such as the Arborloo and the Fossa Alterna.

screenshot from Peter Morgan’s manual on how to build an Arborloo (PDF,~ 3,1MB)

While there’s no single sanitation concept that will work in all places around the world, the VIP for one is a proven technology which has been accepted by its users since 30 years.