Black Tank Chemical Process

Doug33 wrote:

mlts22 wrote:


A black tank here in the US is/should be vented, so odors should not be an issue, especially if one gets a solar fan for the vent cover, creating a slight negative pressure in the black tank.

Where would this vent be on the black tank? Does it go to the roof, or just to the outside under the trailer?
Like you mentioned, I add water softener and soap to the black tank.

Many of the black and grey tanks vent through the roof and have a venturi fitting that helps suck the objectionable odors and gasses when the rig is in motion. Unfortunately some manufacturers, especially of 5th wheelers, only carry this vent to the attic space and not through the roof. No wonder there are problems with odors.

mlts22 wrote:


A black tank here in the US is/should be vented, so odors should not be an issue, especially if one gets a solar fan for the vent cover, creating a slight negative pressure in the black tank.

Where would this vent be on the black tank? Does it go to the roof, or just to the outside under the trailer? And what solar fan are you referring to? Are you talking about the ceiling vent in the bathroom?

Like you mentioned, I add water softener and soap to the black tank.

Here is the confusion I see sometimes:

A recirculating toilet (one that reuses the liquid) requires blue, formaldehyde chemicals to break up solids on the double, or the toilet will be rendered inoperable quickly.

A cassette toilet, which is common in Europe, also requires chemicals to be added to keep odors down (since it isn't vented unless one retrofits a SOG ventilation kit.)

A black tank here in the US is/should be vented, so odors should not be an issue, especially if one gets a solar fan for the vent cover, creating a slight negative pressure in the black tank. So, adding chemicals isn't really needed. The holding tank is essentially a glorified chamber pot, so it doesn't need to have enzymes and such to "eat" waste. All one really needs is some water softener and some soap, which helps dissolve solids and keep them from sticking to the bottom and sides.

Nvr2loud wrote:
I bought my trailer used and firmly believe the previous owner only added poop, and sometimes a little bit of pee, and never any water.

I have been using a cup of laundry detergent and 5 gallons of water. I add those to the empty tank after I dump at the end of a trip. During the travel home and the travel back to the next site in a week or two, it sloshes around and cleans the tank. I then use the tank during my trip (usually only 5 nights). Before I dump the tank, I completely fill it with water... completely FULL and drive over to the dumping station. I dump all that water, fill it again with another 5 gallons and laundry detergent.

I'm getting the gunk out pretty good, even got a fork out once (I have the clear elbow on the drain) and will likely stop using the laundry detergent by the end of this season.

I don't get a lot of smell, but I tell the wife and kids to put a little water on top of the gate valve after flushing, acts like the S-Trap in a residential toilet and no odor comes up from the tank.

I forgot to add this...

When we bought the trailer the tank level indicator always showed 3/4 full or 100% full even when empty. As I've been camping and adding so much water and detergent to the tank, it actually appears the sensors are cleaner now. It registers at the 1/4 level all the time now and then moves up to the 1/2 level as the trip goes on.

I bought my trailer used and firmly believe the previous owner only added poop, and sometimes a little bit of pee, and never any water.

I have been using a cup of laundry detergent and 5 gallons of water. I add those to the empty tank after I dump at the end of a trip. During the travel home and the travel back to the next site in a week or two, it sloshes around and cleans the tank. I then use the tank during my trip (usually only 5 nights). Before I dump the tank, I completely fill it with water... completely FULL and drive over to the dumping station. I dump all that water, fill it again with another 5 gallons and laundry detergent.

I'm getting the gunk out pretty good, even got a fork out once (I have the clear elbow on the drain) and will likely stop using the laundry detergent by the end of this season.

I don't get a lot of smell, but I tell the wife and kids to put a little water on top of the gate valve after flushing, acts like the S-Trap in a residential toilet and no odor comes up from the tank.

I noticed hotter temps add to the smell of the black tank.

If one has a small black tank, "lots and lots" of water may not be the best answer. A decent additive that is competent at handling odours, coupled with half-bowlful of water for #2 is fine. Bathroom fan should be off when flushing and the toilet flap valve is open. Make sure the tank is full when time comes to dump and all should be well.

We use the natural bacteria additive. The brand I like is called Odorless. It's basically the same bacteria that the municipal sewer plants use. It feeds on the gunk you put down the toilet. I dump my tanks about every five days. We use lots of water when flushing. I always flush the tank when I dump (I have a tank rinser on my rig). We add the bacteria additive after flushing and dumping.

It works better than the chemicals, it's cheap, and it's safer. The odors in the summer will eventually come, that's why we dump every five days. We have a family of five, so lots gets dropped in that tank.

Hi,

I don't use chemicals. Use lots of water. Dump often.

If we are only staying for the weekend, two nights, I usually don't bother with adding anything to the black tank. Longer than that I add something, usually more along the lines of a deodorizer.

I am able to rinse out my tanks at home, so after returning home from a trip I rinse the black tank and then fill it with water and chlorine bleach (not too much bleach, maybe a cup?), let it sit for an hour or so, then drain it.