Sceptic Tank Combined With Latrine

It shouldn't affect the functionality. Make sure your latrine is above the same chamber that the house sewage goes to. You also want to install a septic riser, this is a sealed pipe that is installed to bring your hole above ground level. This will prevent your septic from over flowing during heavy rains, and also allow you to seal the hole off when not in use. Finally, I would say, if your going to install an outhouse over this hole, I would make it lightweight, you don't want to collapse your concrete slab. Hope this helps.

septic tanks are anaerobic (the digestion of sewage occurs in the absence of oxygen from the air). Leaving a septic tank open to the air during a water shortage could be very smelly and most probably would interfere with the septic tank working properly. Septic tanks depend on having enough water to completely fill the tank. So if the water shortage is very long and the tank is open you will get evaporation and the liquid level in the tank will be reduced. Maybe if the latrine was connected to the top of the septic tank by a hand-operated "trap door" (hinged to open down), the septic tank problems would be minimized. After using the latrine, you would move a handle that would open the trap door for a moment to allow the feces to fall off of the trap door into the septic tank. Also, if many users are men, providing a urine funnel direct to the septic tank can reduce frequency of use of the latrine (as would peeing in the bushes). Best Regards with your very practical problem. chcaban@mindspring.com

I should have been more specific. A septic tank riser is designed to be used with the existing septic access hole with a fitted top. I would design a seat that could be placed on top of the riser and removed after use, replacing the riser top after each use. This is not something that you would want to leave open for any length of time.

I think you have the process turned around. Your city and comercial systems actually add air and stirr the sludge to get a better air mixture so that the bacteria that breaks down the waste has more of the chemicals that it needs.

The odor that is given off is actually methane gas and is reclaimed in many places for comercial use. An example of this is that the Des Moines, Iowa sewer plant used to capture the methane and pipe it a few miles to a small peaking plant that the local power company had downtown. I do not know if they still do this or not but the joke used to be in the summer for you to eat more beans to stay cool. Then you had to explain the connection.

Rich Hurd

Dreams are windows into the future.

http://en.wikipedia.org/wiki/Septic_tank

Goes to show what happens when you eat too many beans and your brain makes methane. I stand corrected on the septic tank.

Sideline to the natural gas is that the Polk Co. Iowa landfill has installed a series of wells to capture and then burn off the methane gas produced from the landfill.

Rich Hurd

The pipe from your "toilet on the septic tank" must go down into the tank to about 150mm from the bottom of your tank; Same as the inlet of your "in-house toilet' Thus you have less stench and less evaporation from your tank. Put a dead animal or bird in the tank to start it working propperly!

jurie sa

After reading through the comments, i arrive towards this:
Key issue is not to affect the anaerobic functionality of the septic tank.
That means, the Pit latrine hole has to be sealed off when not in use as though it was a manhole cover. The technique of sealing it off is the issue now.

My best option would have been water-seals. However this involves bends in pipes which further requires pressure from water which is not applicable to pit latrines...so water-seals are out. Moreover loss of water was the concern.

So suggestions presented so far can work. See options below for a clearer picture:

(1) [kramarat: ...install a septic riser, this is a sealed pipe that is installed to bring your hole above ground level....design a seat that could be placed on top of the riser and removed after use, replacing the riser top after each use. ...]

-> Requires some bit of design while at the same time minding on the overall weight over the slab.

(2) [Guest: ...a hand-operated "trap door" (hinged to open down), ...]

-> Requires some bit of design while at the same time minding on the overall weight over the slab.

(3) [jurie sa: ...The pipe from your "toilet on the septic tank" must go down into the tank to about 150mm from the bottom of your tank ...]

-> Likewise a very good option but then again, the hole at the top still needs to be sealed off well. That hole, according to my observations is a tricky one but not impossible.

In all these observations, the design must not allow for the solids to stick on the walls of the pipe or similar before the hole.

Nathaniel.
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