Here is the green solution:
1. Take and old garbage can and drill a dozen or so holes in the side.
2. Cut out the bottom (A keyhole saw works great for this.)
3. Dig a hole in the ground, deep enough for the garbage can.
4. Toss some rocks or gravel in the hole for drainage and position the garbage can so it's a little higher than the soil level.
5. Place the lid on top (you might want to paint it with something like Dog Waste Composter.)
6. When you scoop some poop, put it in the hole and sprinkle in some septic starter (available at hardware stores) and add some water.
According to the
http://www.cityfarmer.org web site, "Within 48 hours, the septic tank starter, (which is non-caustic and promotes natural bacterial growth) will have begun its work and you can add more dog doo. You can then begin to add it daily. This waste biodegrades and flows into the subsoil."