Plastic Waste to Armageddon-proof Posts


NAIROBI, KENYA—Little is wasted in Kenya. The plastic containers used to sell cooking oil are reused as containers for carrying water. In fact you find these “jerrycans” for sale in some parts of Nairobi for 0.40 to 2.00 USD. There are three such containers in my house. When so much is reused, it is surprising when, at the same time, so much is wasted.

Dandora is the largest dumpsite in Nairobi (see above). The dumpsite officially employs about 10 people and unofficially around 3,000, the manager told me. The 3,000 unofficial workers are scavengers who dig through the landfill to remove the valuable items such as glass, plastic, shoe soles, wood and metal. That which does not have a market value is left in the landfill. Mostly organic waste and plastic bags.

Plastic Waste

The plastic bags often don’t even reach the dumpsite and instead are scattered on the ground all around town. A group of Kenyans decided something had to be done and started an organization that turns the least desirable part of the waste into plastic posts for lumber. The organization is called Green Africa and is located just past the airport on Mombasa Road in Nairobi. They were more than happy to give us a tour of their facility and even to tell us the cost of the equipment and the buying price of the raw material. Above are rejected wrappers from candy companies.

Plastic Melter

In the above machine, plastic bags are melted into dense nuggets for post processing. Any plastic can be used: PET (from soda bottles), high density plastic (from milk bottles), plastic bags (clean or dirty, though clean are preferred as this reduces wear and tear on the equipment) and even paper with a plasticized covering can be used (the paper will burn away).

Plastic Post Maker

The post making machine heats the plastic nuggets and extrudes the material through a tube of choice (square or round, large or small). Then the foreman removes the tube and dunks it in cold water to make the plastic contract, facilitating removal from the tube. The process is quite labor intensive taking about 20 minutes per post produced. This machine is a used machine from China which costs $25,000 to $40,000. I have seen the nugget making machines at other plastic collection facilities that were made by the local craftsman of Nairobi, the jua kali, but these were constantly breaking down. The current machine makes solid posts but Green Africa hopes to buy a machine that can make hollow posts which will reduce the materials needed but still have the same strength.

Plastic Posts

Jeremiah stands next to a pile of the final product. Green Africa says they have a hard time keeping up with demand even though the plastic posts sell for three times as much as wood posts at between $7 to $12 per ten foot length, depending on diameter. Green Africa gives the posts a lifetime warranty. In truth, these posts will be around long after the roof caves in and the termites eat through your kitchen table.

This is the kind of place I would have visited just for kicks, but this time there were some business opportunities to explore as well.

mai Mahiu

Jeremiah is the co-founder of an NGO in Mai Mahiu, Kenya called Comfort the Children International. The organization has built a strong relationship with the community and recently started a once a month environmental cleanup day and around 300 people join the fun. You see, in Mai Mahiu, there is no waste collection system or dumpsite. Residents dump their waste in the empty plot next door, creating an eye sore for the town and an environmental tragedy. The clean up days are for planting trees (Mai Mahiu has lost most of its tree cover in the last 25 years) and for picking up trash. But since there is no where to put the trash, they must burn it. Jeremiah was looking for a new solution.

We thought we could sell the waste as raw materials and help the unemployed youth earn some money. But there is not a lot of money in scavenging. We let our imaginations run wild and thought of turning the organic waste into compost and the plastic waste into posts. CTC International can organize the youth and I have learned a lot about effective waste collection strategies in Africa that I would love to try out. The plastic posts might help to slow the deforestation rate as well.

Post Maker2

There is even a company (Tujenge Eco Solutions) based in Kenya that produces equipment for turning plastic waste into lumber. All of their machines are exported as there is not much market for them in Kenya. This machine processes 180 kg/hr and costs $274,000!  I think we will have to implement the collection strategy first before investing in the extruder.


Here are the posts the machine makes.

As we progress I will be sure to keep you posted! 😉

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Sisal Biogas

Sisal Field

KILIFI, KENYA—The only biogas plant producing electricity turns the waste from the rope making process into biogas. Sisal fiber is used to make those tan ropes we are used to in the US. The sisal fiber from this farm is sent to the UK for processing into rope.

Sisal Machine

The sisal leaves are ground in this machine.

Sisal Waste

Only about 5% of the leaf is fiber to be used for rope. The rest is waste. The soft flesh of the plant.

Sisal Digester

Sisal waste can be used to feed cows. But on this farm it is mostly for feeding the 700 cubic meter anaerobic digester and runs two 75kW generators at peak operation. The digester is built by a german company. The owner of the digester is a white kenyan who owns many farms and now owns a company called biopower ( This biogas system is their first foray into biogas but they are hoping to build many more for the waste streams of the many fruit processing plants and breweries in Kenya. They are facing a lot of bureaucracy but I am sure they will be successful.

I had never thought of how ropes are made before and hearing the whole process was fascinating. Above you can see the drying system for the fiber after washing. Because Kilifi is on the coast, the water used to wash the fiber is salty and this adversely affects the eventual biogas production from the waste of the sisal. Biogas isn’t a cut and paste solution. It all depends on the local environs.

At the small cottage within the reach of the farm there is also a small digester. I had heard of this design before and remain optimistically skeptical about it.

Plastic Digester

The cost of the digester is lower than underground, cement digesters that my company builds for farmers. And the digester is also portable which would be good for the Masai as they migrate with their herds of cattle. However, the lifespan could be from 5 years on the high end to 1 day if a goat decides to run across the digester and poke a hole in it. UV from the sun quickly breaks down plastic. And the gas holding capacity is suboptimal. Well, good luck to them.

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Kibera One


KIBERA, KENYA—When I returned to my apartment after a business trip, Bernard (on top of the car on his cell phone) explained to me that the orphanage next to my flat had burned down the night before. The cause was either neglect of a cooking fire or an electrical failure; there were rumors of both. Everyone was able to escape safely. In the background of the photo above you can see four boys pulling a disfigured bunk-bed frame from the rubble. The car Bernard is standing on was in working condition before the fire.

Bernard is a swell guy. Some people you just know straight off. When I arrived at my apartment last week he took me around to find all of the things I would need. He manages a health clinic next to the orphanage and he is the manager of the upand-coming Kibera Celtic football team which had a record of 31-3-3 last season and is now in a national kenyan league. The night of the fire he stayed awake and guarded the site. Bernard explained to me that when there is some kind of disturbance in Kibera, some people, especially young men, will take advantage of the disorganization and raid the surrounding area. Such was the case the night of the fire. The mechanic shop and Toi Market were threatened by thieves, but from what I can understand Bernard, the mechanics, et al kept the area safe.

Kibera Plaza

In the background is Kibera Plaza where I live in a two bedroom flat on the third floor. Though the water is sporadic (people have to buy water most days) the location is great and so is the price.

Toi Market

The roof of Kibera Plaza gives one of the best views in Nairobi, I wager. There is really nothing left of the orphanage but scrap metal which will all be sold by the kilogram. None of it will be thrown away. The small fires in the middle of the photo are not from the original fire. In Kibera, waste collection is a joke. People have learned the only way to get rid of trash is to burn it. So that is what they are doing.

My Room

For my house, I have a two bedroom flat with a kitchen and a living room (each room is about 12’x12′). The rent is about 180USD per month. Such a deal! But I don’t have anything to put in the house yet. My only furniture is an inflatable camping mattress. The emptiness of my room sharply contrasts with the fullness of an adjacent room of the same size housing the 15 members of the girls’ football team. Sometimes I feel a little guilty, especially since I spend so little time at home. Most of time is spent on business trips.

Some people scold me for living where I do. (The flat is officially in Kibera, the largest slum in Africa, but in practice the slum is across the road from my flat.) Other people are very encouraging to me. I hoped by living here I would see things differently. I was saddened to see so many people displaced by the fire. But I was thankful that I could be a witness to an event that I would never have noticed if I did not live in Kibera.

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NAIROBI, KENYA—Saturday morning and I was waiting outside City Hall for the sewer engineer to arrive for our trip to the Ruai sewage treatment plant when I felt the need to make a “long call” (as opposed to a “short call,” the east african equivalent of “number one” and “number two”). When I asked the guard to direct me to the toilet he responded “the toilet might not be up to the standards you are used to.” I have been in Africa for four months. I think I have seen bad toilets. And how bad could this one be if it is inside City Hall?

But what I found was perhaps the most unsanitary toilet I have seen yet. Feces were piled so high above the brim that it was impossible to tell where the toilet was exactly. As the toilet tourist I have become, I took a photo and left.


I asked the guard if this was the only toilet in City Hall. He said there were others upstairs but those were for “VIPs” and in any case were locked on Saturdays. By VIPs he meant anyone above the status of security guard or gardener. Someone has to clean that toilet I thought. What is wrong with this place? I still had to go and thought to myself, “if only there is an Ikotoilet around here somewhere.”

And there was. Just around the corner on the very same city block I found an Ikotoilet to my great relief. It was of comparable cleanliness to an average public restroom in the US which by Africa standards is unheard of. Toilet use cost only about 0.07USD.


A few years ago Ecotact started commissioning Ikotoilets around Nairobi to address the sanitation blight that extended to even the richest parts of downtown Nairobi (“Iko” approximately meaning “right here” in Swahili). There are about 10 public Ikotoilets in Nairobi operating on a for-profit model. Friends from Nairobi say that before the Ikotoilets were constructed, traveling in town had to be carefully planned because there was no way to find a clean public toilet.

Shoe Shine

The cost of sanitation is subsidized by rent for a shop built into the structure of the Ikotoilet and a shoeshine kiosk at the back of most Ikotoilets. Other advertisements are placed inside and around many Ikotoilets for additional income. Some Ikotoilets outside of the city turn the human waste into biogas while those near a sewer main do not and instead send the waste to the sewer system.

Perhaps inspired by the success of Ikotoilets, many of the disgusting public toilets operated by the city council have been rehabilitated to a sufficient level of cleanliness. (Well, not all of the city toilets. There are some pretty disgusting ones in City Hall!)

Lifebuoy Advertisement

I went for a field visit with Ecotact to see a few toilets under construction all of which will process the waste into biogas. Ecotact is working on a program to build clean toilets in schools. Funding comes from, as far as I was able to understand, children in the US. The children in the US raise money which goes to building the toilets at schools in Kenya. Then the students are supposed to pair up as penpals to write letters back and forth. I hope it works.

Lifebuoy has a sign on the side of each of the toilets we visited that give instructions for proper hand-washing techniques. In exchange, Lifebuoy gives T-shirts to all of the students and gives a one time supply of soap. If you ask me, they are getting a hell of a deal. Lifebuoy is teaching customers to use their soap at the age of 7. I wonder what brand of soap these kids will be buying for the next 70 years. Perhaps  Lifebuoy could supply soap to these schools for as long as their advertisements are on the side of the toilets. Sure, the kids will still be indoctrinated to buy Lifebuoy but at least the school won’t need to buy soap.


To give you an idea of how pressed these schools in Kenya are for money, at the school above, the school did not have enough money to paint the exterior of the buildings, so Safaricom, the biggest cellphone carrier in Kenya, charitably offered to paint the buildings for free.

Old toilet versus new toilet

In the foreground is a photo of the old toilet at the school and in the background is the new toilet.

learning from the locals

At a market near the town of Kikuyu just outside of Nairobi we visited an Ikotoilet under construction. The matatu drivers and conductors were very curious about this new building. We ended up having a nice talk with them. Will the toilet building have hot showers, they asked. How much will it cost? Can I set up a store next to the toilet? They even got creative: can we use the biogas to heat the hot water for the showers? I love talking to the end users.

In cities land is at a premium. Ecotact developed a way to make the digester more compact by placing the expansion chamber on top of the digester, instead of next to the digester, cutting land use in half.

Ikotoilet stalls

The toilets themselves were designed to be low cost. There is no expensive, imported toilet bowl. This is a good idea. But the toilet hole looks a little too small. And in practice, inspection of the holes showed that students sometimes missed the hole. In the future larger holes might be a better option. The stalls also had a strong odor. Lack of odor is one of the big selling points of biogas systems so I was surprised to find this. The design calls for minimal water usage so the toilets are only flushed a few times a day via a gutter under the row of stalls. Maybe some venting would help the fumes escape. Though I am not sure if the fumes would rise or simply diffuse.

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Adopt-A-Light: My Lesson on Intellectual Property and Partnerships in Africa

Ad Light

NAIROBI, KENYA—Today Nairobi is well illuminated at night especially along highways. I am told that this is new. Until recently there were few lights along highways and those that did exist often did not operate properly. Maybe it is just a coincidence but around this time, Nairobi earned the nickname “Nairobbery.”

Then a woman entrepreneur came up with the idea to post advertisements on lamp posts. She partnered with local authorities to provide the land and electricity to the lights while her company Adopt-A-Light organized the advertising and put up the lamp posts.

The project was a fantastic success and expanded, shining light on more and more of Nairobi. But the local authorities saw how much money was coming in and they wanted a bigger share. All of my data comes from asking Kenyan friends about what happened next but everyone agrees that Adopt-A-Light was cheated. The contract was terminated early and the local authorities awarded the contract to a different company. Other friends suggest that the contract was given to a politician’s friend.

Friends cite this as an example of how intellectual property laws cannot be enforced in Kenya. Even if you patent something the legal system is so slow that the hearing won’t happen for decades. My host-brother was in a car accident over 5 years ago and has been trying to take the responsible party to court ever since. With such a system, it is better to have your technology become a trade secret than a patent.

Other friends cite this as lesson to be learned for anyone partnering with the government. Don’t let them see how much profit you are making because they will want a piece of it. Of course this is a generalization and does not apply to all governmental groups.

Ad Bench

But the idea of advertising as a way to finance public goods seems to have taken off throughout  the city. Benches are billboards that happen to have a horizontal advertisement at siting height.

Ad Trash

Nairobi also has the most effective public trashcans I have seen in Africa, outside of Kigali, Rwanda. When a public good becomes profitable now everyone wants in on the business opportunity. And everyone can enjoy the benefits of clean streets and convenient trashcans. But somehow the slogan “Fresh Breath, Fresh Moments” feels misplaced on the side of a trashcan.

Before I started on this project, I theorized that if sanitation could become profitable in its own right, the world sanitation problem would solve itself. That seems to be what happened with lighting in Nairobi.

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Toilet Pilot

NAIROBI, KENYA—Sanergy is co-founded by the brother-in-law of a classmate from grades 1 to 12. (The other co-founder is also a cool guy but I have no six degrees of separation story for him.) I don’t know how much of the information I got is proprietary so I won’t spill the beans. But what I can say is that I am excited to meet a group with a vision so similar to my own; turning sanitation into a profitable enterprise for the world’s most impecunious. Today they have two pilot toilets and we visited their toilet in Lunga Lunga, a slum area. The Sanergy toilet looks a lot better than the toilet next to it.

Bridge School.JPG

This toilet was at one of thirty Bridge schools in Nairobi. Bridge International Academies is a for-profit company that provides quality education to everyone for about the same price as a public school education. Especially in poor areas like Lunga Lunga, classes can be delayed or canceled for reasons varying from chalk shortages to teacher absenteeism. Maybe for-profit school is a way to make schools more accountable and ultimately make education more available.

Bridge School Kids

The only playground toy in the compound was a cement culvert turned on end but the kids seemed to be having a lot of fun climbing inside.

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Fats, Oils and Greases: the potential biofuel clogging our drains

Flushing Truck

WANDEGEYA, UGANDA—When I was buying fries in the fastfood/street food district near Makerere University where I have been staying I noticed a sewage truck. Mohammed the driver explained what was going on. The 7 inch sewer that services the restaurant area gets clogged several times a week. The unclogging responded to sewer overflow complaints on Christmas Eve, Christmas Day and now they were back on Monday, two days after Christmas. The sewer is undersized for the population it serves but that is not what causes the blockages. The restaurants and food stands in this area dump their Fats, Oils and Greases (FOG) down the drains that empty into the sewers. See below for what grease does to a sewer.

FOG Sewer.jpg unFOG sewer.jpg

Above are photos take of a London sewer before and after the rancid Fats, Oils and Greases were cleared away. The same applies to all sewers of the world so now you know what happens when you dump grease down the drain. Now imagine the impact on the 7 inch sewers of Kampala compared with the one meter sewers of London.


The team of about 9 men blasted water down the triangular sewer cover to unclog it. The water from the sewer overflowed (see the puddles above) and formed a stream going through the parking lot of the restaurants. Eventually their truck ran out of water and the sewer was still clogged.

It is a shame to waste FOG. It contains energy that we could use to our advantage instead of letting it clog our drains. I remembered a company called Black Gold Biofuels based out of Philadelphia that turns FOG into biodiesel and has won much acclaim recently. I went to an internet cafe to see what else can be done with FOG. I discovered studies showing that FOG can be used as a substrate in anaerobic digestion to produce biogas (methane) as well.

The BIG Picture Here is another waste that costs the city a lot of time and money when it could be a resource. An inefficiency is an opportunity. And there are so many stakeholders to benefit from a solution.

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