33% gets flushed down the loo, 25% is used washing ourselves, 18% is spent on drinking and in preparing food, 12.5% is used in our laundry, 8.5% is used when we do the dishes, and 3% is used to wash the car and water our extensive vegetable gardens!
You can see the pie chart for this in the presentation on the right.
A 4 page summary on the humanure composting toilets by Jenkins is posted on the right, as is the piece by Davod Holmgren aplying his 12 permaculture principles to composting toilets.
Recommended Reading on Composting Toilets.
Jenkins, J. (2006) The Humanure Handbook - A Guide To Composting Human Manure. (3rd Edition) Jenkins Publications. My favourite book on composting toilets, so simple, so effective. A wonderful mix of science, humour and common sense. Harper, P & Halestrap, L. (1999) Lifting The Lid; An ecological approach to toilet systems. CAT Publications. A very thorough overview of the compost toilet options available to you, covered in typical CAT thoroughness. Grant, N, Moodie, M & Weedon, C. (2005) Sewage Solutions - Answering the Call of Nature. (3rd edition). CAT Publications. In the same series as the above, but looks at water-based toilet systems and reed beds. Del Porto, D & Steinfeld, C. (1999)
Van der Ryn, S. (1995) The Toilet Papers: Recycling Waste and Conserving Water. Chelsea Green Publishing. Slightly dated but timeless none the same. A compost toilet classic (yes, there are such things!).
Water.
Clift, J & Cuthbert, A. (2006) Water: Use less, save more. 100 water-saving tips for the home. Green Books, Totnes. Simple and useful. Ludwig, A. (1995)
Composting.
Scott, N. (2003) Composting for All. Green Books. Campbell, S. (1998)
Calculating the Potential Rainwater Harvest from Your Roof. (repeated in the persentation above so you could print it)
In order to do this, you need four different pieces of information;
1.The Area of the Roof. Take this as being the floor area of the house.
2.The Runoff Co-efficient. This allows for loss of rainwater, from evaporation or from overflows before it reaches the tanks. For pitched roofs you can have a figure of 0.7, flatter roofs are lower, at 0.5.
3.The Efficiency of the Filter. These filter out leaves and dirt, and lose a small amount of water. Depending on the filter, insert a figure of 0.8 or 0.9.
4.Annual Rainfall. For Totnes, the closest figure I can find is around 1000mm per year.
Using these, your formula is: roof area in m2 x runoff coefficient x filter efficiency x rainfall in mm = annual yield in litres. So, for a house in Totnes with a pitched roof, it’d be roof area in m2 x 0.7 x 0.9 x 1000 = ?
There is also a rather sweet video made by a community in London about how to build compost bins for a community composting scheme. You can also see “Martha” from US television teaching Sesame Street’s Oscar the Grouch how to make compost, which is silly but quite good fun. In fact, as a total aside, you might also enjoy this clip of the Cookie Monster, which has absolutely nothing to do with composting at all. Oh well.
South West Water offer cheap compost bins and rainwater barrels…. you can find out more at the SWW website.