Black tank science

[Turtle_n_Peeps]

Lets talk about the science of poo. It’s important to know the science of poo to know what happens to poo in your RV. This will be a long read even though I will try my best to keep the length down to a minimum.(didn't happen) 😞

I have seen some wild claims on this site so lets take a look at a few shall we.

“My poo don’t stink.” Sorry, but it does. It really does! Bear poo, camel poo, dog poo, cat poo and even people poo; it all stinks! Why? Because of that pesky little unicellular microorganism called bacteria. You see, when living they emit gases. Most of them smell really bad! You have good bacteria and bad bacteria in your gut. All bacteria produce gases. If you have a diet high in sugar, (and who doesn’t now days!) it can make your poo smell really bad! Eat things high in sulphur will also cause you to have a real stinky stool. Really makes no difference, because all poo smells no matter what some members of RV.net say.

So why do people on here claim their poo “don’t stink?” Well; a few reasons I can think of. One of the biggest is losing the sense of smell with age. We lose a lot of things with age and one of them is the sense of smell! If you are older than 60 you have lost a lot of your sense of smell according to the Mayo Clinic. Do you smoke? If so, you have lost a lot of your sense of smell. Smoking damages the olfactory nerves in your nose and when this happens you lost a lot of your sense of smell. For those of you that have smoked and quit you know what I’m talking about. Now that steak or that chicken tastes soooooo much better doesn’t it!

“The pressure of poo.” Another reason is pressure, or lack thereof. You see, when you flush your RV toilet you are directly exposed to the contents of your holding tank. Unlike your home toilet, your RV toilet does not have an air lock. So when you open that toilet trap door the gases have two ways to go. They can come up and waft all over your RV or they can be held down by positive pressure in your RV and go out the roof vent. What is this talk about positive pressure? You see, your RV might have a slight negative pressure and your holding tank might have a slight positive pressure. That is bad because gases, much like electricity, they like to take the easy path, and in this case the easy path is to the negative pressure inside of your RV when you flush. This is the reason you really should not run your overhead fan when you flush your toilet. If you do, you are creating a negative pressure and drawing that sewer gas out of the holding tank into your RV. Ya, not good! Kind of like being in meeting room all day long for a bean convention…….but worse!

“Heat, cold and bacteria.” Much like us, heat and cold can effect how lively bacteria is. “Most” bacteria does not do well when it’s cold. Hence the reason we refrigerate our food. Bacteria does very well when it’s warm or even hot. So if you RV in cold areas more than likely you won’t have much of an odor problem with your poo. Because of work, I typically RV during summer months. This being the case, most of the places I RV in and when I RV are in the 90’s or even the 100’s. This can be a big problem with odor! Ever wonder why you can smell that city sewage treatment plant on the hottest days of summer and not in the winter? Well this is the reason why! Ever wonder why most hospitals are kept cold? See above. Now you know!

“The concrete myth.” I’ve seen many time on here that poo can turn to “concrete” in your tank. They don’t mean it literally can turn to concrete, but that it can get very hard. No, not really. This is ridiculous! You see, poo is a water soluble organic material. If it dries out and gets hard, you can just add water and wala, you have a poo shake again! It really is that easy! When traveling, your black tank is having a literal aaaaaaaaaaaa “# storm “ inside of it. Sloshing and banging, back and forth and up and down. Kind of like a poo blender if you will. Believe me on this, if you have a tank with hard poo in it, all it will take is some water and a little time and some agitation and will turn right back into a poo shake again!

“Water will stop the poo smell.” Aaaaaa, no it won’t. If this were the case, embalmers would use water in mortuaries instead of formaldehyde. If this were the case sewer plants would not smell! Not to say that water is bad; not at all. Water is good! And water is very good in your black tank! Water can dilute the poo and that is a very good thing for several reasons! The more water to fecal mater you have the “less” concentrated the poo will be and the “less” the smell will be. Notice I used the word “less”, and not all. On hot days it won’t do hardly a thing for the smell in your black tank. Remember that the bacteria that is in your black tank is making it smell so bad. Water won’t kill it. As a matter of a fact, bacteria loves moist, damp and wet areas!

“Chemicals.” Oh boy, here we go! Let me begin by saying water does not kill the bacteria that causes black tanks to smell; “some” chemicals do. < Read that again! Now read it one more time! Stomp your feet, jump up and down, cry, snivel and whine; it’s true whether you like it or not. The real question is do “you” need chemicals? I can’t say? You might be a smoker and over the age of 70 and you can’t smell hardly anything. In that case, I would say no, it’s a waste of money. You might have a positive pressure in your trailer at all times and when you flush, hardly any gas comes out. If that’s the case, I would say no and a waste of money. If you camp when it is cold and your black tank stays cold, I would say it’s a waste of money. For “me” I have to have chemicals in my tank. Ok; not have to have to have;………. but let’s say it’s very unpleasant in my trailer when I flush my toilet without chemicals in the tank!
What do those chemicals do anyway? Well, that depends. Some RV black tank chemicals are nothing more than perfumes. IMHO they are not good. What will happen is your poo will have a pine scent smell or a lemon unfresh smell! Looking on the bottle “I” use, it says the major ingredient is formaldehyde. And why do morticians use formaldehyde? To KILL bacteria! And dead bacteria does not gas off like live bacteria do. Hence the reason dry poo doesn’t really smell that bad. When poo is dry, all (most) of the bacteria is dead; and dead bacteria does not have much of a smell; at least compared to live bacteria!

If you want to kill the smell in your black tank you NEED to KILL the bacteria. No if’s and’s or “butt’s” about it!

I hope you had a great time learning about the science of poo and how to mitigate the smell of it in your RV. Happy RV’ing!

[ScottG]

Don't fool yourself, your stuff will indeed turn to a near solid. My buddy has a newer Arctic FOx on some vacation property. He let the contents sit for 4 weeks before dumping. During that time it developed an inch thick, clay-like mat on the bottom of the tank. Liquids happily floated above it all and drained off during dumping and even using the tank flush.
It took a lot of nasty, smelly work to get it all out.

[Lynnmor]

Since your black tank is always open to the atmosphere, and my nose still works well, I say that you folks that make no effort to control your stink are bad neighbors. The water only crowd will be out in force, but they need to justify not spending a dime. This past week we put up with what I believe was a broken sewer pipe venting thru the ground and sure wish that the neighbors would have used something to quell their stink.

[Old-Biscuit]

POO only stinks when you are exposed to it

Chemicals just make poo smell like chemicals

Vapor barriers stop poo smells from getting inside RV just like they do at house

When/if you smell poo then either you have been exposed to poo OR the vapor barriers are broke.
ID/Fix broken vapor barriers and stop exposing yourself to poo....No stink!

Simple.


As for dried out poo going back into solution....MAYBE
But just like that dried dog poo on your shoe water and mechanical friction needed. Sloshing water is not going to do that.
Best to not let it dry out in the first place.

Again...Simple

RVng is NOT complicated. Don't make it so

[DutchmenSport]

Well, I agree with pretty much everything you wrote here ... almost everything.

But I do have to disagree on one thing: The older I get, the more sensitive my nose is getting! Strange as that may sound, but my "honker" seems to have become extremely sensitive in the last few years. I'm 63, never smoked and my "honker" picks up smells and odors that most others never notice or can't smell. For example, when we pulled up to the campsite we are currently at, I stepped out of the truck, walked past the fire pit and smelled cigarettes. (yes,.... really!)...I looked down and sure enough, a dozen or more cigarette butts. My nose drive my wife nuts.

Now, about the rest of your dissertation? I think, pretty much, all you said is correct. However, I do disagree that chemicals are necessary. Why? Well, I don't have an odor problem from my black tank and here's why.

I dump often and flush the thing out A LOT. I back-flush from my grey tank and then will also follow up with the black tank flusher. I have the advantage to dump at home, and it all goes down my septic tank. Chemical are not an option, unless it is household chemicals like laundry soap and bleach for laundry or dishwashing liquid products.

If you consider dishwash liquid a "chemical" (which, in a way it really is), then I do use chemicals.

But I have found, dumping the tank, adding a bit of water, driving to the next destination and letting the contents slosh around, and then dump at the next destination, flush the tank with lots and lots of water, until the contents come out clear and all the globs of stuff stop plopping out, I don't have problems with smells inside the trailer.

Now, when dumping, I agree, it stinks! But draining, back flushing, and tank rinser flushing keeps everything that can grow "bacteria" from finding a permanent resting place on the sides or roof of the tank. That's the secret! Flush the tank. If nothing is in it for bacteria to grow on, then you'll not have smells.

Now... I've noticed my grey tank ... when flushing it, not the shower, but the kitchen sink grey tank ... now that one REALLY stinks when draining it! It smells bad. Every now and then I'll just pour a bottle of bleach down the drain, let the water run about 3 minutes and go for a good drive! That will clean it up pretty good, as long as it's flushed from the chlorine!