10 Months of Hot Water from our compost shower
Our latest compost shower was our most successful ever, giving us fabulous hot showers for 10 months. Here’s an article I recently wrote for PIP Permaculture magazine about how we build our compost shower.
A few years ago we were inspired by Jean Pain’s compost hot water system and as we frequently have extra people on the farm (particularly during our 2 week live in PDC’s) we had a need to create an additional shower with good hot water, so began our compost shower journey.
This system is one that works with our particular environment as we live in a high fire risk area and need to keep the many trees we have planted (especially acacias) maintained for fire risk. Cutting and mulching branches provides the multi function of;
• fire control
• good compost
• heat generated from the compost
Wether you are a gardener with a passion for compost making or a kid that has felt the warmth of a pile of grass clippings you will be familiar with the heat created by decomposing material, our aim is to capture and use this heat…..
Since our original trial we have made around a dozen compost shower heaps, the best of which have given us 5 months of continuous hot water. The most important thing to remember is that we are creating an “anaerobic compost”, which provides the ideal environment for anaerobic bacteria to thrive and multiply (at around 43 degrees). They will work very slowly over a number of months.
Creating an aerobic compost will give a quick and very hot result that will then cool down quickly, great for gardening but not for hot water systems. Below is the method we use but please refer to Jean Pain for a more detailed information (and a far grander scale system).
- a shower, including drainage (ours goes directly to our citrus orchard)
- a water supply with enough pressure for a shower (have cold water going to your shower also as you may need to mix to get the right temperature)
- 100 meters of 20ml poly pipe
- a collection of 20 ml valves, joiners etc
- compost thermometer
- approximately 6 cubic meters of freshly mulched wood chips
- a couple of willing helpersBasically you will be creating a large anaerobic compost heap in between your water supply and your shower. We have enough room to create a second compost and valves that can switch from one to the other, this works well as when one starts cooling down we can switch to the other.It is important to give the process plenty of time as to create the right anaerobic conditions you need to create a moist, compact environment so set aside a couple of days and invite some friends over to help.Start building the pile slowly, adding water constantly and tamping it down continually. When the pile is about 30 cm high add your first
coil of poly pipe, keep the pipe clear of the centre of the pile so as not to get spiked by the thermometer later. Also don’t let the pipe get too close to the edge as it should be well insulated(see the photo below for our first layer). Be careful not to kink or cross the pipe as undoing the pile later to find a problem is not desirable.
Slowly build your compost pile adding another coil of poly every 20cm or so, remember to keep watering, keep tamping the pile and keep the whole process slow.
A few hints ;
• Continually walk, jump or tamp the compost as you are building it. • keep the pile wet during the whole process
• leave a sprinkler on the compost when you take a break
• tamp in the sides to create a a firm compacted result
• put on some good music and dance on the finished heap
forage harvester (this pile worked very well)
When your pile in finished place the thermometer in the middle, if you have got it right it will rise slowly over the next week until it reaches an ideal shower temperature of 45 degrees.
Enjoy your shower!
- Temperature rises too quickly………….your compost heap is attracting aerobic bacteria , squeeze the air out with more water and compaction
- Temperature fails too rise…….too dry, add more water
- Smell……….some of the smell of the compost will be absorbed through the poly pipe, this should not be a problem when making a plant based compost though some people will mention it
- lack of pressure …….could be caused by kinks or leaks in the pipe, do everything to avoid this in the early stages of making your heap
- temperature cools down quickly….look around the pile for puddles as the pipe may have leaked inside
It is an absolute joy standing under a warm shower knowing you are participating in the energy and compost cycle and watching the run off flowing onto the citrus.
There is a huge amount of information about generating heat and energy from compost and we are now keen to explore more, this is simply “our journey so far”.