The amazing world of Composting Toilets!

Who are we?

Gaia Ashram is based on 6 hectares of land that is being afforested and where we work on ecosystem restoration to restore our local ecology to greater biodiversity and at the same time attain enhanced food productivity from the land that can inspire local farmers to make similar changes. Every aspect of Gaia Ashram is designed to reduce our harmful impact on nature and the earth.

What is the issue?

Gaia Ashram is located in the North-East of Thailand where we experience a dry season of about 6 months. Water is a really big issue here and we imagine it becoming a bigger issue in the future due to our changing climate. This year we were experiencing water scarcity at the end of the dry season. Our 34 meter well that we use for our domestic water was pretty dry (we could only pump for 3 minutes at a time) and our ponds were nearly fully dry creating a problem for our agricultural production.

Extreme dry pond at end dry season

This made us the more focused on how we deal with our water. One way to address the issue of water scarcity is to look out our waste water. Domestic wastewater consists of black water containing human and animal fecal matter as well as gray water from household activities like bathing, washing, cooking and gardening. In our current mainstream thinking our blackwater and greywater are seen and treated as waste product that we aimed to get rid of as fast as possible.

Why do we need to deal with our waste water differently?

In the process of treating of our waste water in our current conventional Waste Water Treatment Plants (WWTP) it tends to have a negative effect on the atmosphere as they are emitting all three main Greenhouse Gases (GNHs): Carbon Dioxide (CO2), Methane (CH4) and Nitrous Oxide (N2O) directly or indirectly in significant amounts as to be contributing to climate change.

  • Methane is generated in the water distribution networks and in the sludge treatment.
  • CO2 and N2O are generated during the sewage treatment. N2O emissions from the waste water treatment are the sixth biggest contributor to worldwide N2O emissions.

Furthermore wastewater and sewage enter aquatic systems from sources ranging from surface runoff and septic systems to wastewater treatment facilities and storm drain outfalls. The current dominant Waste Water Treatment Plants (WWTP) systems are only designed to deal with with organic waste not inorganic waste. A lot of the waste water comes with all kinds of human pollutants of which many are inorganic. These are called emerging pollutants.

“These contaminants include mainly chemicals found in pharmaceuticals, personal care products, pesticides, industrial and household products, metals, surfactants, industrial additives and solvents. Many of them are used and released continuously into the environment even in very low quantities and some may cause chronic toxicity, endocrine disruption in humans and aquatic wildlife and the development of bacterial pathogen resistance.


Apart from releasing fast amounts of green house gases that are contributing to Climate Change and creating harmful pollutants for ecosystems, wildlife and humans we tend to use enormous amounts of water to flush our toilets, shower, bath etc. which all gets mixed up and ends up into the sewage system. The average household in the UK produces 150 liter of wastewater a day and in the US this is averaged at 370 liter a day.

From the chart we can see that Toilet flushing makes up the bulk of domestic waste water. In a home with older toilets, an average flush uses about 13.6 liters, and the daily use is 71.2 liters per person per day. In a home with ultra-low-flow (ULF) toilets, with an average flush volume of 6 liters, the daily use is still 34.4 liters per person per day.

Moving towards a thriving biosphere…

As we as a species are evolving towards a life sustaining or an ecological society all aspects of our lives are to be redesigned to healthily feed into and enhance life systems and the biosphere. At Gaia Ashram to change the way we deal with our waste blackwater we created a dry composting toilets system. We already had a lot of experience with composting toilets as we were pooing in buckets for about 6 years and created big composting piles for the management of it. This system works really well and is especially great when pioneering land but requires intensive management. Another great pioneering system to look into is the arborloo (

After many years of pooing in buckets it was time to up our game and have more comfortable toilets. For the design of our dry compost toilet we were inspired by the amazing work of Joseph Jenkins and the Humanure handbook (we will give link at end of article) and the permaculture body of knowledge on this subject

The Compost Toilet Design:

Our long time friend and inspirational permaculture teacher Ben Murray through his visiting of Gaia Ashram and his teachings supplied us with the necessary info to design the dry composting toilet. In the design process itself we had help from our Permaculture friend Goustan Bodin. It was a nice easy going process, back and forth brainstorming and we had some valuable feedback from other community members as Goustan gave a presentation about the initial composting toilet design during one of the courses held at Gaia Ashram.

This was the initial design and later we made some adjustments. As we wanted to maximize the use of space we also integrated a shower block and washing area.

The Compost Toilet Build:

Gaia Ashram hired a local Isaan building crew to get the job done. For this structure we decided to do a recycled green building instead of a natural building as it includes a lot of wet areas especially the shower and the poo holding chambers. The compost toilet structure itself was made of about 70% of reclaimed and recycled materials.

The roof structure is made from recycled metal, roof itself recycled metal sheets, all doors recycled, even the locks, railing recycled, stairs from recycled steel, walls made from reclaimed broken chunks of brick from old house (seen from pic below), windows recycled and we integrated broken tiles found next to big tile-shops that throw them out. The building process needed good planning and communication as it was an unconventional build for the builders. The clear design from sketch-up really helped with the communications with the local guys.

The labour involved in dismantling the house to provide the recycled building blocks was a big expense and the workers asked us why we do this. We told them we rather pay them to do this then give the money to the big company to buy all new materials. The materials we extracted from the old house we have used in three different structures already, we also use it to create garden edges and also use it in our rainwater collection ditches.

The result and here is how it works:

Upstairs are two toilet rooms with two toilets. We have one sitting toilet and one squatting toilet. Both of them have a urine separator that channels the urine through piping into a big IBC tank (see pics below) from where we can use it by diluting it with water and spread around the land to fertilize it.

We have been using the human urine on our crops on our big field for rice through fertigization and in our foodforest using a little sump pump:

For more in depth knowledge on using human urine in agriculture please see the following link:

In the toilet rooms there are 4 holes with underneath it four poo collecting chambers. Two per toilet room. We put the toilet on one hole. This is the active chamber if the active chamber is full we move toilet to other hole. After pooing you can add some water through the bumgun and toiletpaper to clean yourself and then sawdust. We created a large carbon sawdust material storesupstairs that are connected (see pic above) to the inside with a hole so it easy to fill sawdust in toilet.

Above is the picture of the back of the toilet with the four chambers and doors. Inside the active chamber (middle pic) as long as you cover with straw, leaves or other carbon rich material there is no smell. Almost weekly we will add some ash, more carbon material (different types like leaves, straw, paper) water and sometimes add some nitrogen rich materials such cowpoo, banana trunks or kitchen scraps to make the compost more rich and to also feed the composting worm that we added. Another great addition is biochar especially in tropical areas where we experience high soil nutrient loss and also reduces potential smell. The pile tends to shrink a lot, this is shrinkage is increased with the introduction of worms who chew up the organic matter and poo it out in even smaller size.

To size the chamber you can keep the following calculation:

Input volume per person per day.  Industry accepted capacity calculations are based on  ~ 0.25 gal. (about 1 liter) per adult per day total volume of combined feces, toilet paper and dry carbonaceous material”


For us it was difficult to calculate the volume as we have fluctuating amount of people using it. Sometimes we have 30 people and sometimes just 5 people staying at Gaia Ashram. As we integrated the showers in the structures the chambers are high and we feel it is more then enough space for poo collection. After almost 7 months of use the chambers are not even half full yet. So we have plenty space in the chambers. Ideal size for good composting is at 1m3 or 3 feet high, 3 feet wide, and 3 feet deep. (

As the pile is not super high yet we can open the door still and we added some metal sheet to stop it from falling. When the pile gets higher we have an access hole in the toilet itself to be able to stir and add materials. It is good to add water in the system as long it is not to much. To dry and it wont compost well and we actually had a situation where the straw caught on fire in peak dry season as we forgot to water it down.

For humanure composting you want to make sure it composts for a long time to kill any potential harmful bacteria recommended at least a year. We want to stimulate aerobic bacteria in the biological composting process. As in general we have a hot climate here in Thailand which speeds up the composting process and also the addition of worms and based on our observation of our bucket compost toilet system we feel that we can use it after about 8 months of closing the toilet and put the compost around our fruit trees.

Happy composting and pooing everyone and if you have any questions about our composting systems feel free to email us: also like our Gaia Ashram facebook page (see on the side of the page).