Chlorox in your black water tank?

I just put some chlorox in my black water tank.  It took care of the odor instantly. Later someone told me that Chlorox will cause damage to the seals in your tank.  Has anyone had any experience using Chlorox?

I had a full time neighbor ask me for some nitric acid. He had piped his sewer in with PVC pipe. Not understanding the proper pitch of drain piping and keeping the black valve open they developed a cone pile in the tank He hoped the acid would dissolve the pile. I did suggest bleach a cup or two to a level of liquid to cover the pile. Not a fan of strong acid, bleach does loose the chlorine quickly. It did dissolve the pile, he started using the black valve and he has had no seal problems since Late May.

Now why a odor from the tank that is the real question.
Jim

I have heard the same thing. Never used bleach myself, be sure to flush it out real good. If you keep plenty of water in the tank you shouldn't have an odor problem.

I've always heard that the problem with bleach, or similar, is that it kills the bacteria you need to complete the "breaking down" process.  It can also damaging to the system that you dump into. 

Since the black tank on a RV is a batch system you do not have a residual build up of bugs. You start over each dump. A little bleach to remove buildup is not likely to harm even a small septic tank, now like most things a little goes a long way and if a little will work a lot is not better.
Jim

I wouldn't worry about the seals if the bleach was anything like diluted. Now if you just poured a gallon of raw bleach into an empty tank, that might be a different matter.

But bleach is generally not a good thing in the black tank. You want bacterial action to "eat' the solids and residue. As Jim says, a diluted bleach rinse now and then is not a problem, but please don't dump it in all the time, and please don't flush lots of it into campground sewage systems. Those nearly always have large septic tanks and the bleach stops the bacterial action that makes the septic system work properly. Ditto for any product containing formaldehyde.

People use bleach everyday for cleaning chores and laundry.  It all ends up in a sewer system or septic tank somewhere.  Your black tank is NOT a septic system.  It is designed to hold everything suspended in a liquid form until it can be drained.  It is a holding tank and its' secret is plenty of water.

I have recommended the use of bleach in moderate amounts before to control order and been soundly chastised for the advice.  Fulltiming in the heat of a Central Texas summer requires some bold actions at times -- bleach WILL kill the odor in a stinky black tank.  I would not advocate its' use on a regular basis

At the job site I am at now we installed a 400 gallon septic tank in January.  2 RVs are hooked to it.  I have used bleach 2X so far this summer in my black tank.  The septic system is still perfectly functional.

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Several months ago I became a convert from commercial holding tank chemicals to Dawn and I'm pretty happy with the results.  I also began a rinse ritual which includes flushing the tank prior to travel, adding back about a third of a tank of fresh water, 1/4 cup of Dawn and about a 1/2 cup of bleach to slosh around while driving.  Sometimes for good measure (and to turn over the old ice cubes in the ice maker) I'll dump in the ice cubes.  I do this every couple of weeks.  Everything's been smelling like daiseys... or lilacs, depending on which flavor of Dawn I use. 

I think I've gotten a buildup of junk in the gray tank now and with advice I pickep up here from Gary, I'm trying to fix that up using Roebic enzyme septic treatment.  I think historically I've paid too much attention to the black and not enough to the gray tank and fell into the habit of leaving the valve open.  Probably was a bad idea.

Well, gang, Dr. Science here again for another episode of mythbusters.

Laundry bleach starts out life as a 6% solution of sodium hypochlorite.  It weakens over time while the bleach sits on the shelf at the store or in your basement or whatever, because some of the chlorine diffuses through the walls of the jug by osmosis and into the air.

In water chemistry, we consider the amount of free chlorine that is present.  Free chlorine is any chlorine ions present that aren't attached to a carbon or nitrogen atom.  Laundry bleach has about 5% free chlorine when fresh.

Free chlorine reacts with organic materials to produce organochlorides and chloramines.  In general, in a holding tank with a large accumulation of solids, it isn't possible to get much free chlorine by adding bleach, because it will all react quickly with the organic materials that are present.  Many of the organochlorides and chloramines are volatile and will effervesce out to produce the "chlorine smell" which is why there is more of a "chlorine smell" when you put bleach in a holding tank than there is when you put bleach in a freshwater tank, since in a freshwater tank the chlorine stays in solution.

You're not going to kill all the bacteria in a full holding tank, let alone a septic tank, with household bleach unless you're buying the stuff by the pallet, because it only takes about half a pound of solids to react with all the chlorine in a one gallon jug, and after that the chlorine loses its activity against bacteria.  You might, with couple of cups of bleach, kill enough free-floating bacteria and bacteria on the surface of any solids accumulation, to reduce the odor for a while, but bacteria deeper in the solids accumulation will eventually recolonize the tank.

When adding any chemicals to the holding tank, I take care to avoid getting the chemicals in contact with the seals on the head.  Chlorine in sufficient quantity will attack the seals on the dump valve.  Dump valves are cheap, and on most rigs, easy to replace, so faced with a solids accumulation that can't be removed by other steps, chlorine might be worth it.

THANK YOU Dr Science!  Great explanation.  It took me a while to get it though my head that my black tank wasn't a "septic" tank but then I was a bit worried about the impact of bleach on the systems in parks.  I can rest easier now.

Thanks again.

My thanks too, Dr. Science Jammer. And excellent explanation of the science behind what several had said here.  Most any chemical, used in moderation, won't harm a septic system or a cess pool or a holding tank. They are a pretty hardy system, all in all.

I have to take a bit of exception, though. We often run our black tank 7-10 days between dumps and in that time, it does act much like a septic tank, liquefying waste so it can easily run out the drain line. The drain isn't open continuously, as it is an a septic system, but the biologic action is no different.

Campground septic systems are hardly normal, though. They often get hundreds or even thousand-plus gallons of effluent dumped in a short period (around checkout time), then have to struggle to recover before the next day's onslaught. And many are undersized for the abnormal cycle of heavy loads they get.  Lots of chemicals in lots of tanks exacerbate the problem, so help out and be kind with the volume of chemicals.

Thanks for all the information.  I plan on using the Dawn and bleach method.  I will also try to be kind to the camp ground sewage system.

I guess I am just lucky.  My s*** don't stink.  JMO.

maverickbbd said:

I guess I am just lucky.  My s*** don't stink.  JMO.

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I've been waiting for someone to use that line!  Love it.  ;D

Dawn & Clorox works mostly because you probably don't need anything anyway. Many of us here put NOTHING at all in the black tank  and do just fine.

Dawn is a degreaser, and in that sense helps get the crud off the sides of the tanks. Bleach kills most all organisms (so does the Dawn), so in the short term kills odors.

RV Roamer said:

I have to take a bit of exception, though. We often run our black tank 7-10 days between dumps and in that time, it does act much like a septic tank, liquefying waste so it can easily run out the drain line. The drain isn't open continuously, as it is an a septic system, but the biologic action is no different.

Campground septic systems are hardly normal, though. They often get hundreds or even thousand-plus gallons of effluent dumped in a short period (around checkout time), then have to struggle to recover before the next day's onslaught. And many are undersized for the abnormal cycle of heavy loads they get.  Lots of chemicals in lots of tanks exacerbate the problem, so help out and be kind with the volume of chemicals.

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Gary I agree that the subject of campground wastewater treatment is both interesting and complex.

I live near a state park.  Since it is run by the state, they are not subject to the state dept. of health regulations regarding wastewater treatment that would apply to any private enterprise.  They have a large settling and holding POND where they accumulate water for treatment.  Exactly what treatment takes place is unclear (I suspect they're evaporating water to reduce the amount they have to dump) but the campground fresh water system has been shut down due to contamination on at least one occasion.  However, back to the subject at hand, the pond is large enough that I doubt the "batch effect" at the end of a holiday weekend matters much.  Also, typically, holding ponds like that are kept chlorinated to avoid producing any odors that might upset the neighbors.  Of course, some of their neighbors run livestock confinement operations and might not notice.

So in this particular case I suspect that if someone poured a pallet or two of bleach into the dump station no one would notice, except that the automatic chlorine feeder wouldn't be injecting as many chlorine pellets or gallons or pounds of whatever form they use that week, because it has a sensor like a thermostat that shuts it off when there's enough.

I believe that due to the application of residential rules most campground wastewater systems are oversized by almost an order of magnitude.  A typical household might use 300 gallons of water a day, and campgrounds have to be sized as though they have one "house" per site, though the rules vary from state to state, as does enforcement.  Even on departure day that's a lot, and if the campground has a residental-type system the septic tank is typically sized as a multiple of the daily usage, 2x, 3x, 4x, depending on how many chambers it has and the jurisdiction and so on.  Larger campgrounds have systems that look more like small municipal designs, like the state park next to me.

And some places that are highly seasonal and have unfavorable geology just have holding tanks and pay to have them pumped and hauled.  The RV dealer where I bought my rig does that, as does the campsite I am parked at right now -- it's only open 8 weeks a year and is on a site with 2 inches of topsoil over bedrock.

So I don't know for sure, but I think that it's a stretch to think that excessive chlorine could actually pose a problem.  Now, the formaldehyde products, and quaternary ammonia products, might pose more of a problem if overused, because they're more persistent.  Which, on the other hand, is why they work so well.