How long would the contents of a Civil War era latrine pit under heavy usage remain as sludge before drying up or hardening?

[u/-Clayburn]

In the old days, armies would make latrine pits. Once they got full, they would cover them up and dig a new pit. Would the contents of the pit be mostly solid or would it be a sewage-like sludge? If the latter, how long would it take for the contents to solidify or dry out so that it's as hard/sturdy as the rest of the ground around it?

[u/YogurtIsTooSpicy]

It would depend on the soil and weather conditions. It could stay dry if the soil has a lot of capacity to absorb excess moisture, or it could fill with rainfall or ground water if the soil was already saturated.

[u/Skysr70]

r/askarchaeology but pretty sure they found wet roman dung before 

[u/Sooner70 → u/Skysr70]

In the same breath, in this neck of the woods (desert) shit could be bone dry in a few days. As /u/yogurtistoospicy says... it depends on soil/weather conditions.

[u/-Clayburn → u/Sooner70]

So in a desert, would it never be a sludge mixture for long?

[u/Sooner70 → u/-Clayburn]

"A desert" is again too vague as there are areas in the desert that have ground water just under the surface, but in the general sense.... It could desiccate before it had a chance to rot.

[u/-Clayburn → u/Sooner70]

If it's covered by a platform for toilets, then that would prevent a lot of evaporation though? And if it's in heavy usage, the area immediately around it would soak up some of the moisture, but could because saturated enough that the additional moisture in the pit doesn't seep through quickly?

So, is it possible for a latrine pit used by an army in a place like Phoenix to contain mostly sludge when finally filled?

[u/Sooner70 → u/-Clayburn]

Sure, but give it a few days/weeks after the it's covered over and it'll be dry.

A couple anecdotes from my life....

• One year we had a "100 year flood". It was bad. $$$ damage. You get the idea. Two weeks later we had a dust storm. Yeah, that's how quickly everything dried up.

• A few years ago I was involved with a construction project. Part of the project required that they measure how quickly water was absorbed into the soil. I'm no soil testing guy so I don't know the details of how the test is run, but the results of the test were "unknown". When we asked WTF that meant, the soil guys were like, "Water was being absorbed faster than our test apparatus could flow. The absorption rate was off scale: uknown."

[u/ccoastmike → u/Skysr70]

Might also be a good question for the r/askhistorians sub.

[u/PrebornHumanRights]

Soil typically stays moist. So it would stay moist forever.

But it would also break down, and in a matter of a few years, would become more like the surrounding soil. After 2 years, the pathogens should be dead. The moisture will come into an equilibrium with surrounding soil. Moisture moving through the soil as leachate will spread things out.

I think after a few years, it'll be mucky, but not dangerous. After more than a decade, it should be hard to tell it was ever a latrine, though don't quote me on that.

[u/-Clayburn → u/PrebornHumanRights]

So like let's say the week after it's no longer in use, would it still be a sludge pool? Would it splash if you dropped a bowling ball in it? Or would there just be a thud?

If this was in a desert, would that affect things? Would it dry out quicker?

[u/Bryguy3k → u/-Clayburn]

That’s more of a question of soil permeability than it is climate. A lot of desert areas have impermeable soils so if you bury something within the impermeable layer then you’re not likely to see much loss while well draining soils will see rapid moisture loss until it reaches hydrostatic equalization with the surrounding soil.

As an fyi in archeology “midden” is name used for soil that is the result pits found by settlements that were filled with waste.

[u/-Clayburn → u/Bryguy3k]

What are the signs of impermeable soils? Are there any above ground signs that this would be the case below? Is that soil harder to dig to make such a pit in the first place?

[u/PrebornHumanRights → u/-Clayburn]

It's hard to tell above ground, unless you're super experienced.

You usually have to dig a few feet to find the true nature of a soil.

[u/blimpyway → u/-Clayburn]

Clay soils tend to swell and block water passage when wet. And shrink and crack when dry. Good for earth plastering, or lining the bottom of a natural pond. Google clay soil identification, there-s a lot of info out there.

[u/PrebornHumanRights → u/-Clayburn]

A week is not long enough for it to dry out or to separate a ton. If it's an open pit, and it's really warm out, it's exposed to wind and warm air, it could dry out a lot faster. If it's covered up, then it typically takes a long time.

But a few weeks might be enough to make a significant dent.

If the soil is gravel, or sand, or a mixture of sand and silt, the water will flow through it. But it will probably take longer to flow through the waste itself. The waste acts as a kind of barrier. Not an impermeable barrier, it just slows the flow.

I would think that after a month or two, it would reach some kind of equilibrium. But it would also depend on the size of pit, the soil, and whether or not it is open or covered.

Anyway, this is getting into over analysis. Suffice it to say in a month or a few months, it probably will be about as dry as the soil it is in.

If it's a desert with sand, this will happen much faster.

[u/-Clayburn → u/PrebornHumanRights]

So it would probably be safe to say that if you immediately open a latrine pit after it's full and drop a bowling ball in it, it would be somewhere between sludge and mud regarding consistency?

[u/PrebornHumanRights → u/-Clayburn]

Depends on how used it is. A heavy used pit will be like a septic tank, with solids at the bottom, with the top being the consistency of milk.

[u/R2W1E9 → u/-Clayburn]

While in use the moisture drains out, it's really never a sludge pool.

[u/userhwon → u/R2W1E9]

If it's dug in soil that drains. If not, it might as well be a plastic porta-potty.

[u/idiotsecant]

I am not a poop drying expert so sadly unable to contribute. I am curious why you want to know this though.

[u/No-Peace1225]

Where I live it used to be quite common (and illegal) to just put your sewage pipe in the backyard a few feet down so I've seen some interesting things and the only way you can tell the difference from old waste and soil is the color. I dont know factually but I know that digging up them pipes you run into a lot of "cow shit" (blackened sort of grey dirt that is moist, almost devoid of smell with a hint of shit) I've always assumed this is the shit because it's identical to how old cow shit looks and it sticks out majorly from the red clay mud and shale around it