permaculture alison€¦ · web viewthis might give me the incentive if i see a lovely pile of...

Project 6Compost Toilet (2010)

Summary and Lessons Learnt

A simple yet effective design for catching wasted nutrients and saving wasted time in the garden. This project has been a talking point during Open Days and greatly improved the rhubarb and currants but has not been taken up by the family other than me, so some work to go fully integrating it into the house system is required. As a design it fulfilled my brief, but not the families so it was good learning experience on how to accept feedback and PR permaculture!

EthicsEarth Care- The motivation for this design was to create a sustainable alternative to a flushing toilet for use when in the garden, to catch nutrient, especially nitrogen from urine for fruit crops.People Care- This has improved my efficiency when working in the garden and is pleasant and satisfying to use! Not sure the family would agree!Fair Share- A real talking point and opportunity to share my knowledge if not my urine! Abundant fruit crops appearing will be shared in the form of jams and fruit wines however.

Criteria and Principles Demonstrated

The framework for this project documentation came from thinking about Holmgren’s Principles and applying them to the design process and thinking that evolved over time. The main principles demonstrated include Accept Feedback and Self-Regulation, Obtain a Yield, Catch and Store Energy, Produce No Waste, and Observe and Interact. The design required periods of Observation and Evaluation, and has been a Rolling and Incremental design.

of 12Compost Toilet Design by Alison Ensor

Compost Toilet

A handy outside loo to stop me having to go back to the house when I’m working in the garden had been on my wish list for some time when I started this diploma. Walking back to the house for a pee takes a few minutes each time but it’s a distraction and I often lose momentum and start doing some house job instead. I have been peeing in a bucket in the polytunnel as neighbours walk past which is not good in a relatively see and hear through polytunnel!

I’m also very conscious of the wasted nitrogen leaving my permaculture circle. My newly planted willows have been very slow to get going when left to their own devices, despite being mulched and watered, probably due to my rather sandy soil. So I thought maybe I could utilise the unused resource of my own personal waste. I like the idea of a bottle of urine as a liquid feed for my hungrier summer crops too.

Having just got rid of my compost bins to practice composting kitchen and garden waste directly on the soil I was not keen to be handling buckets of unpleasant stuff in another separate composting area, so I wanted a very low maintenance in-situ set up. It also had to be odour free and pleasant enough not to put off the rest of the family as I wanted to use this as an experiment for developing a suitable system for inside the house. I’m quite happy to save my morning ablutions until I’m down the garden letting the poultry out each morning but the rest of the family are not that excited about the idea for some reason.So as this is something of an experiment, I’m loath to spend much if any money on the whole thing until I have some idea whether the design is feasible or will actually be used!

Requirements Summary To provide a handy garden loo Collect urine for fruit/veg fertiliser Provide nutrient for willow fuel crop and basket weaving materials Low cost, waste materials at least for trial In-situ system, ie no separate composting area A pleasant experience to entice the family to use it hopefully! Provide learning experience to develop a design for an in-house system


The DesignThe most obvious choice to meet the above was to build a compost toilet with a urine separator, that required no handling or moving of the dry material. A tree bog perhaps? But I didn’t fancy building a large raised platform which would require more resources than I currently had. So I have adapted the tree bog idea to be more like a garden privy, where by the whole set up is temporary and easily moveable to a new position.

‘The Garden Throne’

The structure sits over a 60cm hole in the earth. After each year the whole structure (which is lashed rather than nailed together) can be shifted along 1 metre and willow planted over the newly capped hole beneath. The grass beneath the floor will have been killed by the light exclusion from an old butyl pond liner, allowing the willow to get away without competition when planted surrounding the previous year’s hole. The butyl liner will also prevent the pallet and box from rotting from ground moisture or splashes from the toilet, and allow cleaning. I’m hoping it will also prevent flies accessing the pit but observation will show if this works.


Trellis on the rear may make the whole structure look prettier but time will tell if I can grow any annual climber up this north facing side. I shall make trellis from grown willow if possible.

I thought perhaps a hand washing system might be useful using captured, filtered rain water, accessed by lowering the tube from the overflow pipe. Painting the plastic bottle black will prevent the water from turning green and might allow some solar heating of the water in the summer (when the loo will be most in demand!) In freezing weather I’m not usually down the garden. If the roof fails to catch enough water, rain water from other butts can be used to top up the bottle. Principles Employed in the Design Process This design came from observation of my behaviour and thinking about the materials I had to hand and the most suitable location. The design also evolved over time through trial and error. Using Holmgren’s Key Principles as a framework has helped me to understand and document this journey.

Observe and interactFor 6 years I’ve observed my walking up and down the garden to have a pee and found it frustrating as a waste of energy and focus.

Digging pits for clay in this area (for the clay ovens) I’ve noticed that the soil is very sandy for the first 50-60cm and then meets a kind of sandy clay and even after heavy rain there does not appear to be a water table at this depth. There is no water course nearby.

My intention is to observe how quickly a 60cm pit fills up and if it is not full within one year then I can dig a shallower hole next time. The 1 year cycle would be ideal for the purpose of establishing new willow each spring. The structure is only lashed together to enable easy movement each year but I built the structure for several weeks before I furthered the design to check its durability and it happened to withstand some severe SW gales. Time will tell!

The site I have chosen faces our hedge and the rear of a neighbours stable block which is never accessed except for when we maintain the hedge, so it’s pretty private. The area in front of this hedge is pretty poor for winter crops due to lack of light (shading from the stables in low sun months) – so as only half productive land I thought I’d give it over to willow.

Catch and store energyClearly the whole purpose of this design is to catch the fertility from my pee and poo and enable me to catch more energy from the sun in the form of willow and comfrey biomass.


The structure also catches rainwater from the roof and saves my own energy from walking back to the house.

Obtain a YieldI’m getting a fertile pit every year, a bottle of liquid feed every fortnight perhpas, willow for fuel every 3 or 4 years, willow for basket weaving and next year’s planting once a year. I’m also getting some peace and quiet down there!

Self-Regulation and feedbackThis system will only work if I choose to go outside, rather than use the house loo. Integrating a house composting loo (which will be a bucket type) will require more self-regulation on my part(guess who will be emptying the bucket) and some on the part of the family to actually use it. To enable the integrated system to work will mean me taking note of all feedback and adapting accordingly. Renewable ResourcesThe building materials for the structure are all recycled waste, except for a previously bought plastic flat roof sheet, unused from the previous house (about 10 years old, a great testament to my hording wisdom) and a bought plastic toilet seat with urine separator (on ebay). I tried adapting a plastic bottle to collect urine but failed to catch anything. This seat is weather proof, hygienic and an effective wee collector – and can be reused in future iterations of the design if needed. Even the plywood box for the seat started life as a duck house!

Produce No WasteThe system is made from waste materials and turns a previously unused ‘waste’ into lovely willow and food crops. I’m also saving the water that would have been used to flush the toilet each time I go.

Multi-Functional designThe main functions of the design are to provide a private toilet area for the garden and capture nutrient for willow and veg production. The design also provides a hand washing facility and potential vertical growing space. It could also act as a place to dispose of dog waste in a more useful way than the current hole in the ground in the garden (which is too shady for willow planting). In the future it could act as a teaching resource for potential course attendees and at this point in time it’s a learning resource for me and my family!

Relative LocationThe location of the toilet within the main veg area serves the purpose of saving time whilst gardening, and fertilising a future willow coppice spot. The site is walked past every morning when opening up the geese, so is ideal for capturing the moment! Its location


behind the neighbour’s stables means it is secluded and wind protected and also downwind of the seating area next to the pond, in case there is any smell problems.

Implementation DiarySeptember 2010 – Main structure built from reused pallets (originally intended for new compost bins) and nylon string for easy untying. Trellis thing not going to happen!

October 2nd – survives major storm. Extreme winds failed to blow it down, very pleased with design and placement in lea of neighbours building.

October 8th – Design completed apart from hand washing part. Using small amount rainwater collected from roof, to rinse separator part of loo seat to prevent slight smell. OK other than that.

October 20th – First full bottle urine/water filled, emptied onto compost bin


The pallet structure is lashed together (so I can dismantle easily if need be) and is lined with old carpet, looks a little rough but strong! Open side facing private hedge and the stable block rear.

Seat with urine separator and pipe leaving left to bottle – see above

Hand washing tube inserted in overflow blue pipe. Filter basket can be just seen in top of black bottle.

November 4th – Second bottle full – approx. 4 litres per fortnight. Overflow to hand water working Ok but careful not to push too far down pipe as you get a syphoning effect. No problems with smells or any sign of flooding in pit.

December 2010 – Severe snow and cold weather meant I have not been using the loo. Also the geese have been transferred to the freezer so I am not walking this way every morning which means a special journey is needed, not inclined if very cold or raining. January 2011-Weather still off putting , miserable and wet. Either I move the toilet closer to the chickens but not keen due to privacy issues, or I need to introduce internal compost toilet to augment the outside design. Preferred idea!

February 2011-Using toilet again occasionally and structure still sound despite a winter of bad weather and recent severe gales. I have decided to augment the system with a new toilet in the bathroom, to increase nutrient capture for the coming growing season. Also have planted several new trees and could do with the compost/feed to get them off to a good start.

Improvements on DesignApril 2011 After 7 months of regular use the hole is only about 2/3rds full but I have some willow saplings that I want to relocate so I need to move the toilet on this spring. Also, after talking with my husband about why he’s not using the outside toilet I’ve decided to rebuild to make it more ergonomic for his size, as currently it’s not comfortable for him being too low and narrow (but perfect for me!). I’ve been saving bits of old shed and materials so it is relatively easy to dismantle the temporary pallet shelter and build the new one above the new hole.


June 2011 - New build loo finished

The structure has been made more solid with sections of shed and taller and wider to allow for my husband, though he still is reminded to sit with a slight head height restriction. The whole structure looks more like a small shed so less ‘challenging’ for visitors to view and even use occasionally! The roof has been made from off cuts of polycarbonate roofing saved from the greenhouse project, so is very strong and windproof.

Note : - this picture was taken in October after this new design had been up 5 months. There are 2 willow plants and 1 poplar planted around the old hole but the only one doing well is the poplar. Other willow planted near the duck pond and in receipt of much more water as a result has grown 10 times better. I have a feeling that this area close to the hedge line is rather too dry for the willow even with regular watering of diluted urine. I intend to trial more poplar (again grown as fuel crop) instead of willow in this spot when I move the loo along again as it seems better suited for the conditions .

Also I intend to get rid of the water capture for hand washing as this has never been successful (there is so much bird crap on the roof I rather not wash my hands in it!) and the unit clogs with algae. I therefore intend to catch rain water from the roof and pipe it directly to the coppice area- which probably means changing the guttering to the other side of the structure and hence the direction of the roof slope!

Internal Compost Toilet Design – The Bathroom Box!

After the experience of winter but buoyed up with the thought of even more urine to help my saplings get going, the internal compost toilet came even more of an interesting prospect to get off the ground. The house offers no option for a permanent ‘drop through’ to a composting chamber type set up, so this trial was always going to be a ‘bucket and chuck it’ variety.The design is as simple a urine separation system as I could make.


Design Update 2012 – Just angling the floor very slightly has enabled run off from the roof to water poplar sapling directly without any need for guttering!

Notice urine collecting bottle.

The box will fit into our upstairs bathroom and is made from 9mm ply plus the same plastic toilet seat as was used in the outside toilet design. This has proved very accurate at collecting urine and is easy to clean –the whole seat can be lifted off in this design (along with urine pipe) which means I can clean it under the bath tap. The only drawback is it comes without a seat lid so I have made a box lid out of ply to fit over the entire seat, including the gap at the seat base, to prevent flies getting in. I may decide to make the same kind of lid for the outside toilet if flies prove a problem in the summer months.

The urine is separated off into a collapsible water container which is see-through so that I can easily lift the hinged lid and see if I need to empty the urine bottle. The box allows easy access to remove the bucket and/or urine container. The bucket will be emptied into the hole of the outside compost toilet which is easy to get at by moving the outside toilet ‘box’ from off the hole in the pallet floor as this is not secured down.


The completed bathroom box – the jug of water is to ‘flush’ the urine collection section and hose after each wee otherwise it can start to smell in warm weather. Close fitting lid sits over the seat and makes whole thing very discreet!

Implementation DiaryApril 2011Using the internal toilet most of the time though still not convinced children – bucket needs emptying about every 5 days to stop smells which do build up after this time. I’m emptying the bucket into the outside toilet and this seems to be OK . Sprinkling urine on straw mulch beds to encourage faster breakdown and feels better than just watering around fruit bushes/trees.Empty wee container every week – getting upwards of 5 or 6 litres a week

August 2011 – Only using internal toilet for wee’s- Proving too smelly for number 2’s even if emptying every third day which is a bit of a faff. Probably not using enough soak (loo paper and cardboard) but the emptying itself is a nuisance and I’m just as happy using the outside loo every morning. Still no sign of child use except once in an emergency during a house party when all toilets occupied! Collecting masses of wee though and think runner beans love it!

Winter 2011/2012 – not using at all due to fact I have no need for urine in the winter months. The outside loo captures enough to keep the compost bin active and to add to straw mulch to encourage nutrient breakdown. Also still using outside loo first thing when releasing chickens if weather not too bad (it has been much milder this winter) so that ablution is taken care of! Will start up again in the spring when things start growing and I need the nitrogen.

Project Evaluation Having gone through several seasons and a few design iterations I feel I have given the internal and external compost toilet a fair trial, and have come up with positive and negative conclusions from both systems.The External toiletS uccessful aspects of the external toilet trial have been

1. The external toilet is still in use after 16 months2. Pleasant to use, no smells and can bird watch whilst on the loo!3. No fly or rat problem4. No flooding of the pit has occurred5. Windproof despite the worst of weather6. Provides plenty of urine in the growing season7. Talking point!

Not so successful parts of the trial and my suggested improvements1. The family totally unconvinced and only I’m using regularly, the teenagers not at all,

and my husband is happy to wee directly on the garden if he’s outside anyway. He’s perhaps used it for the other once or twice a month when working outside at weekends .


Resign myself to this and carry on leading by example!2. The willow hasn’t really taken in this situation

Try using poplar instead and watering directly from roof. I don’t want to move the toilet to a more willow suitable area as this has proved a good place in terms of privacy and wind protection.

3. Hand washing not successful , water dirtier than hands! Unnecessary, I’m either working in soil or going back to house after opening chickens so wash hands anyway.

The Internal Toilet S uccessful aspects

1. Fantastic amounts of urine collected during growing season – 5 litres a week!2. Great when water gets turned off and can’t flush!

N ot so successful parts of the trial and my suggestions1. Only partial use due to the smell build up quite soon.

Source more pleasant to use soak as have been reluctant to bring messy straw into house, eg source cheap mdf-free sawdust? Or buy wood shavings for horses? Trial and if still not working only use for urine collection.

2. Found emptying and cleaning of bucket a hassle so more inclined to use outside loo, except when weather cold. Crucial point of whole experiment, will only work as far as I can be bothered to make it work and place nutrient capture over ease of flush toilet!

3. The inside loo has not provided alternative to outside loo, as I don’t have enough need for urine in winterUse on a straw bale over a bed in winter to generate compost for spring use? This might give me the incentive if I see a lovely pile of straw bale compost appearing.

This project had the following requirements at the outset which I feel have been met. To provide a handy garden loo Collect urine for fruit/veg fertiliser Low cost, waste materials at least for trial In-situ system, ie no separate composting area

The following have only been partially successful A pleasant experience to entice the family to use it hopefully -

The outside is more pleasant than the inside, but neither have been accepted by the whole family. I will try again with wood shavings to see if better soak will counteract the smell problem.

Provide nutrient for willow fuel crop and basket weaving materialsStill to be judged on performance in following years with increased rainwater directed onto area and/or use of poplar instead.

Provide learning experience to develop a design for an in-house system


The outside loo encouraged me to build the internal one, yet the two systems are quite different and not sure I’ve cracked the internal one yet!

Overall the success of this project is dependent entirely on the user’s motivation to overcome the ease and habit of a flush toilet. I am more motivated that the family because I need the urine but in the winter my motivation goes down too.

If we had no alternative toilet then this would be a perfectly serviceable solution , because the family would just get used to it. Whether the outside hole in the ground system would work if the whole family was using it constantly I doubt, due to the scale of waste created. It would then have to become a composting system.

In terms of collecting nitrogen for the garden though I am a committed wee separator. And as a handy outside toilet whilst working in the garden it has proved invaluable. With these two aspects being the projects primary motivation, judged against this criteria alone it has been a success.

Conclusions - 2013What I have learnt from this project is a lot about self-regulation. Of all the projects I have undertaken this one has required the most change in behaviour to make it a success, precisely because there is already a useable flush toilet indoors! Changing existing people behaviour is an interesting aspect of the requirements that I will really need to think about and build in to any future design. How to recognise the level of ingrained attitude, how to challenge and bring about change? How to prevent slippage back to ‘normal’ behaviour as opposed to more environmentally aware one? Most of all, how to give ownership to the whole family/set of users and not just the permaculturally inspired ones!

As an evaluation of the design process I used, Holmgren’s Principles provided a framework for explaining what I had done in retrospect, but it does not give the same stages of the process that OBREDIMET does for instance. Most of my thinking for this project was done standing looking at materials I had to hand and pondering on my site and my own habits. Often when designing I just follow my nose without thinking of the design framework process – unravelling this into a diploma write up then requires a lot more formal thinking afterwards. Holmgren’s principles do enable this but the actual design process is more easy to explain if using a proper structure.


permaculture alison€¦ · web viewthis might give me the incentive if i see a lovely pile of...

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