Conservation Forum

Sustainable Green Toilet Project

The development of a green toilet project is underway working with ACEF charity, which supports 1000 children that attend the Brainhouse Academy situated in Mathare North, Kenya – one of the world’s largest slums. The school was established by the local community in 2003 to help educate street children, vulnerable children and children of families who could not afford the cost of education. The project is working towards making the school more sustainable and self sufficent.

Any questions, please contact Katie Thompson on

Scroll down to find out more about the project developments…

Home made cooking stove from a coffee tin!

Published on 30/07/2017 by James Cooper

Project manager James Cooper has been busy building prototypes and recently reached a milestone, producing a stove from a coffee container with biogas. showing that it is now producing flammable gas!

Thermometer reading on BD2 after greenhouse construction

Published on 16/07/2017 by James Cooper

The greenhouse seems to have done the trick. 34.3 degrees in Bio-Digester 2! Perfect!

BD2 also produced some gas today for the first time. Not enough to really test if it’s methane, but it’s encouraging and hopefully produces more tomorrow. Once I’m certain I’ve got flammable gas, I’ll know the acid-eating bugs that produce the methane (methanogens) are growing well and can control the pH. Then I can start adding food waste to ramp up the gas production.BD1 also looks like it’s returned from the dead after suffering from leaky seals for weeks and then going acid. The pH levels are back to normal, the seals are holding and there’s gas slowly bubbling from the pipes. It’s been a good day in the Biogas Stories.

Thermometer check and greenhouse implementation

Published on 13/07/2017 by James Cooper

Trying out this aquarium thermometer on (BD2) reading of 22.5 degrees. Not bad, but not enough. The anaerobic bacteria in this system are used to living in the gut of an animal, so they like pretty warm conditions.

Ideally, I’d operate BD2 in the ‘thermophilic’ temperature range, which is above 45 degrees celsius, but this would require another heat source. So instead I’m aiming for the ‘mesophilic’ temperature range of 25-40 degrees celsius. It should get there on warm sunny days, but we don’t get too many of those in the UK.

8 poles from an old tent, 4 bamboo canes, 2 plastic tubes from a broken football goal, 1 roll of duck tape, some plastic sheeting, a couple of hours of playing around, and one cup of tea.

DIY greenhouse…done!

Biodigester 2 complete (BD2)

Published on 18/06/2017

This anaerobic digester is made from a 100 litre water butt. It’s about 5 times bigger than BD1, so in theory it should take about 5 times as much food waste each day (up to about 5 litres a day), and produce 5 times more biogas. The larger volume also makes the internal conditions more stable (temperature and pH) which is great for the bugs, and the 110mm diameter feed pipe is much easier to use.

I was a touch nervous about gluing on the lid, but the water level has held at the top of the effluent pipe for a few days now, so it’s looking good. That’s a win for No More Nails. The Uniseals securing the pipes are also working well.

The next step is to seed it, introduce the anaerobic bacteria needed to break down the food and produce biogas. I’m planning on using the fertiliser produced from BD1, as well as some small contributions from my dog!

Prototype biodigester number one (BD1)

Published on 09/06/2017 by James Cooper

The first attempt of an anaerobic digester! It’s a fixed, continuous digester with a floating gas storage system. The three containers were all found as rubbish, and most of the components were found rummaging around in my Dad’s garage. I sprayed the digester black so that it heats up better in the sun.

The digester works by breaking down organic waste (food waste in this case) in an environment with no oxygen. Anaerobic bacteria then turn the food waste into biogas (a flammable mix of methane and CO2) and a nutrient rich liquid fertiliser.

This digester was initially filled, or ‘seeded’, with a bucket load of horse manure. Not a pleasant task, but I had to get those anaerobic bugs from somewhere. I then dealt with many problems, mostly to do with leaking. I bought some new seals and had my first experience using a drill and holesaw to cut perfect circles into the digester for the pipes to fit into. Note to self, cut all holes before you fill the container with horse poo! Messy!

I’ve had only about a litre or two of gas so far – I suspect the rest has been leaking out of the seals – but that was pretty awesome anyway, to make fire from banana peels and apple cores. After the modifications last night to the seals, I’m hoping I’ve finally cracked it and it starts producing gas regularly.

I’ve got a few more improvements to make to this model, and I’ve started sourcing components for Biodigester 2.

Initial visit to Kenya, Mathare

Published on 09/05/2017 by James Cooper

The purpose of our visit to Kenya last in April was to begin work on the Green toilets project. This project aims to design and build a new block of toilets for the Brianhouse academy school, a school located in the middle of a slum in Nairobi.

The current facilities are…not the best. They’re small, dark and smelly. Although this is an upgrade on the ‘flying’ toilets found elsewhere in the slum (you basically poo in a bag and fling it), a new toilet block will be great addition to the school.

However these green toilets will be no ordinary toilets. Our intention is to design a system where the waste falls into a biodigester, turning faeces into biogas. This gas can then be piped to a gas stove and used to cook on in the kitchen, rather than burning wood and coal.  This has massive environmental benefits and will save the school a lot of money, meaning they’ll be able to feed more children and buy more equipment for the school.