Why is There a Black and a Gray Sewage Tank?

[Bigd9]

Ever wonder why there are two tanks instead of one larger tank? Is there some sort of law demanding this? Just curious.

[cutrell01]

Originally Posted by Bigd9

Ever wonder why there are two tanks instead of one larger tank? Is there some sort of law demanding this? Just curious.

You don't want a 100-120 gal tank with all that crap sloshing around when you are driving down the road! Talk about steering problems!!!

[Okotok]

I can say I like the fact that the gray flushes the hose after dumping the black, especially if there is no water available at the dump station. Even if there were, clean-up would still be somewhat yuckier if everything dumped as one.

[buck454]

Originally Posted by Bigd9

Ever wonder why there are two tanks instead of one larger tank? Is there some sort of law demanding this? Just curious.

Not sure why....but I am glad they separate them. I have been caught in a tight where I needed to get rid of some gray water without dump station. A little gray in a bucket then disposed of the best I could was not to big of a problem, any black could be a no fun, smelly task.

[RickO]

I too am glad they are separate. When in a pinch, it might be possible to dispose of grey water when dumping the black tank would be out of the question. Plus, I really wouldn't want only the water in the P traps separating my kitchen sink from black water.

I'm sure the size of a combined tank is the reason for separating them. I have a 107 gallon fresh water tank and don't think it adversely impacts handling.

Rick

[Auto hauler]

More than any other reason is the black tank of off the toilet(s) is a sewage/bio-hazard and needs proper disposal. The grey tank from sinks, shower, etc. is just dirty water, no hazard to to the environment and doesn't really need proper disposal. The age old concept simply keeps the real sewage to a minimum.

I used to do mobile and modular home setups. Mostly out in the sticks on private property. On quite a few of those setups, I'd split the plumbing system. Have the toilets go directly to the septic tank. The brown water would bypass the the tank and go directly to the lateral field pipes.

It is all just an old waist management concept from the backyard outhouse days brought up to current times.

[Savagendn]

Originally Posted by Bigd9

Ever wonder why there are two tanks instead of one larger tank? Is there some sort of law demanding this? Just curious.

At first it would seem easier to have just one .but anyone whos ever had that grey tank get so full it starts coming up into the shower are really grateful they separated the 2 !

[Mr_D]

Originally Posted by Auto hauler

The grey tank from sinks, shower, etc. is just dirty water, no hazard to to the environment and doesn't really need proper disposal.

Don't try that in WA or OR, here grey water must be disposed of the same way as black. In OR it's been that way since the 60's or early 70's.

[Cilrah]

Originally Posted by Savagendn

At first it would seem easier to have just one .but anyone whos ever had that grey tank get so full it starts coming up into the shower are really grateful they separated the 2 !

I second that thought, I'd hate to see any blackish gray water coming up in my shower. Also could you imaging the smell you might get while working over your kitchen sink

[SpringerPop]

Originally Posted by Auto hauler

..... On quite a few of those setups, I'd split the plumbing system. Have the toilets go directly to the septic tank. The brown water would bypass the the tank and go directly to the lateral field pipes.

Though you believed you were doing the customer a favor, there's a real problem with your method.

The solid organics from toilet and kitchen waste eventually become "bacteria poop", and fall to the bottom of a septic tank. It is much like carbon black at the end of several "layers" of bacteria "digesting" it all.

The body oils from showering, and vegetable and animal fats from dish washing, need to be also separated from the "clear effluent" that is sent to the leech lines. It is what develops into the "scum mat" that floats at the top of the septic tank.

The septic tank acts as a "filter" to remove solids from clear effluent. Both the carbon and the scum need to be professionally pumped out and taken to a real waste treatment plant every few years, frequency depending on usage. It's like cleaning the "filter".

With your way, the greases will "clog" the soil, resulting in premature septic system failure.

An exception to this might be the laundry water, laden with light soils, greases, and detergents. A small, separate seepage pit filled with crushed rock will save the leech lines from some effluent disposal, increasing their effective "life". The location would need to be changed periodically, too.

Health authorities DO frown on this, however, and will insist that it ALL go through the septic tank.

I realize this has nothing to do with our holding tank discussion, and apologize for going off-topic.

Pop

[Dunner]

My 5er had 118 fresh and 40/40 B/G. Explain that.

[SpringerPop]

Somebody WANTED you to have an over-flow, maybe?

Has it ever happened, or are you a "good manager"?

Pop

[Auto hauler]

Originally Posted by SpringerPop

Though you believed you were doing the customer a favor, there's a real problem with your method.


Pop

I totally get that! But that trick only happened per customer request. If they wanted it done, which quite a few did, and it meant keeping a sale, we'd go ahead and do it. I wouldn't do that separation to my own system, short of the laundry discharge as you mentioned.

[Ancabuild]

Originally Posted by Dunner

My 5er had 118 fresh and 40/40 B/G. Explain that.

How about the extra fluids coming out of you and your camping bodies plus some other liquids you may decide to pour on the sink as you go?