Disposable diapers are very hard on the environment. That's why my wife and I use cloth diapers. Instead of sending pounds and pounds of soiled diapers to the dump every week, we simply wash the diapers in the washing machine. However, you can't just dump the dirty diaper directly into the machine! That would be... truly nasty. You have to clean off the majority of the solid waste before it goes into the laundry. Sure, you could use paper towels or wipes or something to get the chunks off, but that's a waste of resources and it takes too long and it's smelly and gross.
So why not spray it off -- directly into the toilet? Commercial units that do the same thing cost $40-$60, but you can make one for $30 or less if you have the parts lying around.
EDIT: Instructables member Catflavor has alterted me to the fact that some sort of backflow prevention would be a Really Good Idea for this installation. In fact, it may be a legal requirement where you live. In Canada, either a vacuum breaker or an RPZ (Reverse Pressure Zone) valve may be used, and the sprayer will then be completely up to code. Unfortunately, these are somewhat expensive and complicated to install. I'm looking into my options and will report back. In the meantime, if you use this sprayer, I suggest shutting off the water at the valve before releasing the sprayer trigger *just in case.*
AND A PLEA: Please vote for me in the Epilog Contest! Why? Because if I win, I will be donating the laser cutter to the fledgling Maker group starting up in my city. It would go a long way towards our goal of a Maker/Hacker space in Waterloo!