Such a rich discussion. Wondering why I am late to the party!!

I think treebog is a beautiful innovation that can work very well in rural alreas, not prone to flooding. I agree with Alisa, she said

In most of the refugee settlements I've worked in (and visit), there is simply a very high density of people. Thus, the Treebog system is not technically scaleable in most high-density environments. 

To Alisa, Jay, Ross, and others, the question I have is:
what will it take to make the treebog work in denser environments?
I mean it may not be able to cater to very high density, but what could be done to make it work for a little higher density? 

Regards
paresh

Hi everyone,

Very interesting discussion. I am currently implementing Container-based Sanitation at scale in Uganda and Kenya. I do not believe the Treebog approach is scaleable in most high-need contexts we get invited to work in — informal settlements, urban areas with non-sewered sanitation, schools, refugee settlements, and rural towns. 

First of all, I don't think we should call these chambers compost chambers. According to the United States Composting Council (presented in full quotes here):

The official definition is: Compost – is the product manufactured through the controlled aerobic, biological decomposition of biodegradable materials. The product has undergone mesophilic and thermophilic temperatures, which significantly reduces the viability of pathogens and weed seeds, and stabilizes the carbon such that it is beneficial to plant growth. Compost is typically used as a soil amendment, but may also contribute plant nutrients. The prior definition was: The biological decomposition of organic matter. It is accomplished by mixing and piling in such a way to promote aerobic and/or anaerobic decay. The process inhibits pathogens, viable weed seeds, and odors. (Official 1997) “The USCC has been working on quality compost for 25 years, and we don’t want to have the compost industry’s product being confused with other products after all the work we’ve invested in best practices and quality product standards,” said Alexander, who spearheaded the AAPFCO workgroup that has worked for two years on the new definition. The new definition also helps the makers of other products, from biochar to mulch to dehydrators and anaerobic digestate, to more clearly describe their products, as well.

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GiveLove utilizes a CBS approach without urine separation based on a modified Humanure Composting approach developed by Joe Jenkins. We are implementing at scale and composting on slabs (using decomposed granite and gravel) in Kampala, and other prepped ground surfaces using a biological sponge inside brick bins. Our systems do not produce leachate and we document the high temperatures and compost phases, including sufficient curing time. Site design and preparation take a lot of time and we work with environmental engineers to construct our sites properly. 

Heavy rain fall is a very real problem in many contexts. In Haiti, I worked with Habitat for Humanity to remove the Otji Toilet system when the poop slurry never decomposed or dehydrated. Over 300 households were burdened with a failed system. Before we recommend systems for refugee settlements we should take into account how these systems work at scale. In terms of behavior change and self-management, we also need to look at lifecycle costs and environmental impact (as people point out here).

In most of the refugee settlements I've worked in (and visit), there is simply a very high density of people. Thus, the Treebog system is not technically scaleable in most high-density environments. 

I also think we need to critically take into account the use of the term "composted or "compost" in the description of this process. The process does not meet the definition of composting by any EPA, WHO, or any other professional standards. Composting requires a correct c:n ratio, containment, aeration, and adequate heat treatment and curing phases. 

There might be some level of  pathogen reduction via microorganisms in the Treebog system,  but arguably not sufficient to reduce pathogens to safe levels in a refugee settlement, where disease spread is a concern, in addition to nitrate run-off into the groundwater or surrounding water resources. Cholera, Ebola, and parasites are serious risk factors in many parts of Uganda where hundreds of people are living in temporary and permanent refugee settlements. 

Alisa Keesey

Morning Jay. I can see where there would be separation on contact with the pile however I still cannot see how some absorption from the pile would not occur. Once mixed the affected urine would then continue in a contaminated state (presuming there are
 pathogens present) to  a waterway.
Regards     Ross

Hello Ross,

Some people do build Treebogs with urine separation.

However, because the pee drains off the pile, by gravity flow, it is separated from the solids - which stay in a pile and compost into soil.

I have used a Treebog for almost around 35 years, and have observed this 'separation' first hand!

Cheers,

Jay

I still  have a problem with the urine not being separated from the solids. I agree that by mixing we elevate the pathogen travel to any ground waters. 
Cheers    Ross

Using a wetland design to clean sewage is outstanding.  It allows plants to gradually clean while water is slowly flowing through the wetland and at the end it is clean and can flow into the natural salt or fresh water.  I don't know why more developing countries don't use it.  Once the grading and berms are built there is very little maintenance required.

Dear Anthony,

Yes, it’s almost like digging holes is a part of being human!

Digging holes for pools/ponds, for ditches, holes to store things in or to dispose of wastes, mounds and trenches for defence, ridge and furrow to manage water in the landscape, Motte and Bailey, and of course the Chinampa wetlands of Mexico…the list goes on and on.

Through Biologic Design, I am lucky to be able to dig holes for a living for the ‘construction’ of the wetland systems we create using permaculture design principles.  These Wetland Ecosystem Treatment or WET Systems are densely and diversely planted, soil-based wetland ecosystems which integrate water purification, resource production and increased biodiversity through habitat  creation.  

They hold water in the landscape as a part of water retentive landscape design - on any scale.

They are as Bill Mollison put it they are an example of the  'recombinant ecologies' we need to create to repair the damage wrought on the Earth.  These ecosystems comprise all of the six great kingdoms of life - The Archea, Bacteria, Protista, Funga, the Plants and Animals - which are given a place to flourish, within a designed, specifically constructed and densely planted 'Land:Water Harmonic'.  

A wave form of water and earth - which can change depending upon local conditions and what yields are required from the 'system'.

See attached drawing of examples of the most productive Land:Water Harmonic there have ever been - The Chinampa - from Permaculture: A Designers’ Manual, by Bill Mollison, which outlines all of the Permaculture Design Principles and Design Directives necessary to create regenerative human habitation, and has been the basis of my design practice since 1992.

All the best,

Jay - Biologic Design

The treebog has benefits if it is needed in a crisis where a sanitation system is needed NOW.  I am still concerned about pathogens.  I realize that a treebog is built above ground but as you mention the liquid is absorbed by the soil and have the potential of reaching the ground water.  In many cases water is gotten from a hole that is only 3 to 4 feet deep.  Many of the pathogens have lives of up to several years in low temperatures so there is time for the pathogens to travel to the ground water.  In addition I am concerned that the above ground treebog will attract flies.  As you state it is an aerobic system meaning that air is introduced which would allow flies and other insects access to the feces.  A study analyzing what happens to the excrement and the pathogens is needed before I could recommend it.

BTW, people using arborloo latrines or tree bogs probably don't even need a structure. They simply throw a cloth over themselves. My first experience seeing this was fifty years ago in West Africa (but now I'm boasting).

I stand corrected. But you must admit that in a many contexts the arborloo is preferable. It seem that appropriateness is on a case by case basis. BTW, in lots of cases people have ways of digging holes. It's not as is someone has give them a shovel.

Hello Anthony,

Thanks for your interest in the Treebog.

I will respond below to your comments and questions concerning the Arborloo as compared to the Treebog:

Comment
It seems as if it would be a lot easier to dig a hole and make a platform over it, as in the Arborloo. 

Response
How is digging a hole easier? 
It is much easier not to dig a hole!  
Especially in rocky ground or in shallow soils.

Also, with a Treebog, when the contents are fully composted, it is not necessary to dig the compost out of a hole in the ground, but to simply move the compost pile into a wheelbarrow or basket - at ground level.

Comment
The Treebog would involve building a structure above ground with a platform. 

Response
The materials required to build the Treebog and the Arborloo structures are the virtually the same.  
Although the Treebog does not require a concrete plinth as does the Arborloo, it does need to be raised up by at least one metre off the ground to make space for the composting chamber underneath the platform.

Question
Wouldn't it be better for the excrement to be below ground?

Answer
Why would it be better to have the compost below ground?

With a pit latrine the liquids and the solids are in the pit together.  

Aerobic composting occurs in a Treebog, whereas in a pit latrine of any kind, being underground, the waste materials are far more likely to become anoxic or anaerobic, and so create an odour nuisance.

In anoxic or anaerobic conditions the composting process is slower, this is because the lack of oxygen means that fungi, which are obligate aerobes, cannot function to help in the process.Also, with a pit latrine, groundwater is more likely to be polluted, as the excrement is brought closer to it by digging the pit.

I hope this answers your questions and you are now more clear about the benefits that a Treebog can bring.

If you have any further questions please get back to me by email: This email address is being protected from spambots. You need JavaScript enabled to view it.

With best regards,

Jay
Biologic Design Ltd.

Hello Elisabeth,

The difference between a Treebog and an Arborloo is that an Arborloo is a pit latrine and a Treebog is not.

If you look at an earlier part of this thread, I have already sent a fairly detailed document which addresses the questions asked by about half a dozen other members of SuSanA

Treebog: DefinitionTreebog can be simply defined as a raised, platform-mounted, toilet cubicle, closely surrounded by densely planted and heavily mulched trees and shrubs. In terms of its structure, there are many possibilities when people self-build, using local resources.
The term ‘Treebog’ is spelt in this way, capitalised, so as to stress the importance of Trees in the creation and successful functioning of the Treebog.

Note that ‘bog’ is an informal word for toilet in the UK.

A Treebog is not a pit latrine
As the Treebog is not a pit latrine, there is no need to dig a hole underneath it. 
This not only saves a lot of labour, but can be important in helping to protect groundwater, especially if there is a high water table.

Treebog: Soil surface compost chamber - not a below ground pit
Having no pit prevents the mixing of liquids and solids in the Treebog and so helps to prevent odour nuisance.  To make this as clear as possible we describe the enclosure underneath the platform, surrounded by the chicken wire, as the compost chamber. 

Platform mounted, directly above a compost pile.
The Treebog cubicle has either a toilet seat or a squatting platform and directly below this, in the compost chamber, is the compost pile, onto which the daily offerings are deposited. This simple use of gravity, to create the compost pile underneath the cubicle, results in users only ever having to move the pile when it has fully decomposed into compost, they never have to move either sewage sludge or any non-composted material.

The Arborloo 
The Arborloo is another type of compost toilet, a methodology already accepted in the field.  The Arborloo is only similar to The Treebog in that it involves a tree being planted.   In the Arborloo the tree is planted into a pit which has already been filled with toilet wastes.  So, an Arborloo is a full up pit latrine, with a tree growing it. When an Arborloo pit is full, it is covered with a layer of soil and a single tree is planted on top.  However, it is still necessary to dig a pit, which is labour intensive, may bring septic wastes closer to groundwater and can be very difficult, or impossible, in rocky conditions.

The Arborloo - Short-lived tree is planted
Guidance on the Arborloo indicates that a short-lived species, like the banana, be used and once the tree dies off, then the pit is dug out and used again. 

The Treebog - Long-lived trees are planted
In contrast, the trees around the Treebog can grow and produce resources for many years, they can be managed as standards or coppice, and produce fruits, nuts and many other useful tree ‘services’ including shade from the sun and shelter from the wind.

The Treebog’s Water Retentive Root Zone
The platform-mounted toilet is surrounded with closely planted trees and shrubs.  These send their roots into the moist, nutrient-rich soil underneath and around the Treebog, opening up channels in the soil for water.  In doing this, the tree roots create a water-retentive space within the soil underneath the Treebog, enabling more water to be more readily absorbed in the soil; to be absorbed by the roots and transpired by the leaves of the trees and shrubs.

Please do get in touch if you need any further information.

With best regards,

Jay