i have been composting dog poop for a couple years now. the big thing is to try and keep it form going anaerobic. Dog poo composting, if working well, wont stick bad.
If you have the space (we have 2 medium sized dogs and need about a 10x10 foot area).
Take the poops and put them on concrete, or wood/plastic/metal. anything that stays dry and bakes in the sun. keep in a sunny spot. We live in the "city" a bit, and use our roof for this, its a flat roof which may not be like your area. after about 4-8 weeks, depending on the amount of poop and the intensity of the sun it starts looking more frail. use a stick and it should be kind of crumbly. At this point we bury and mix it with dirt and leaves to keep air levels up and bury it in a hole. We plant fast growing annual kind of plants that dont seed heavily. Usually some kind of nice looking, not weedy, morning glory. this helps keeps bacteria and such in the root areas which seems to help decompose the poop better. every year teh plants are cut down and laid ontop of the area to also compost. after 2 years a 3x3x3' hole looks like nothing more than compost. and this way it never gets stinky. except when first drying it.
we used to just dig holes and fill. but we found that, especially after rains, it would compress down and become anaerobic and all the nasty bacteria start to make their presence. which is fine, but the smell isnt nice and this matters if your in a city type area and have neighbors.
We just moved recently and have an abandoned fenced field next to us...so we do teh obvious super lazy method of "shoveling it over the fence" now lol. But we did fence in teh area we shovel to so no kids play there. its about a 20x10' area super filled with weeds, so the poop decomposes really fast.
i love that idea of a doggy septic tank! IN fact, why cant we just add them to our own septic tank (if you ar eon septic rather than sewer)? The process is all the same, and i bet the poop eating bacteria and such are not so species specific... Could it be done to have a few bendy pipes (to avoid smell, just like houses are plumbed) and just dump the doo into your tank and spray the hose down to clear up and stragglers? what an incredibly fun idea! thanks for posting that.