Back when I spent a year living on the English canals, my narrowboat ended up grounded in rural Northamptonshire for 2 or 3 weeks owing to low winter water levels. Inconvenient but not a disaster. Until my onboard toilet tank filled up. Whenever I needed a crap I had to line the toilet bowl with clingfilm, carefully wrap the product and fling it across the canal to the wasteland on the far side, away from the waterway and the towpath. Not something I’m proud of, but it turns out that such ‘flying toilets’ are common practice in some of the poorly serviced shanty towns of Kenya.
This post at islamonline.net discusses the problem and the use of biogas latrines as an appropriate, low-tech solution. The latrines are easy to build and maintain and convert human waste to compost for agricultural land and methane gas for fuel. As the need to conserve water becomes more acute, I can see these installations spreading across industrialised countries.
In Canada, the City Farmers have posted, among many other instructional videos and articles, information on how to compost pet waste, or ‘doggy doo’, which must be a boon for all pet owners.