Composting Head - No need for Black water tank

[BackofBeyond]

So, as I await the build and delivery of our E-II, I am mulling over a few ideas for improvement. With our selection of Nature’s Head Composting Toilet the black water tank becomes superfluous. Has anyone thought about repurposing it into a secondary water storage. (It will be untarnished - new) Seems plausible, will have to look closer after I have my unit in hand. I enjoy the many Ollie owners on the forum who posses a similar "I can make that better" gene. Having built 3 conversion vans, I appreciate the engineering and build of the Oliver but that doesn't stop my tinkering mind. There is always something to be improved. Ha, perfection is always an elusive mistress.

[topgun2]

Cindy & Russel (and Harley) -

There has been a fairly lengthy discussion on that very subject here. I believe that John Davies was either the originator or had things to say in that regard. You might want to PM him.

Good luck.

Bill

[Overland]

I don't know if the black plastic is considered to be food safe, so that's your first thing to check. Second, Oliver cuts a hole in the top of the tank since they're convinced you'll want to poop in it one day, so you'll have to repair that. Connecting the two tanks shouldn't be difficult, but you'd probably want to research spin welding - there's a description here if you search for fresh tank water pickup. Then you'd have to lengthen the breather/overflow on the fresh tank since at the existing height it would just drain out most of what you put in. After that you'd be done, since you could fill both tanks through what would have been the black tank cleanout port.

 

I think you'll find that you'll want to swap out the tank, which probably can be done through the dinette seat access. However, the tank itself is a custom size and shape so it might be expensive to have made.

[BackofBeyond]

My thought was as a supplement only. As for the "poop" hole, if the tank is removable I could seal it and reinstall. Do not intend to connect the two tanks, use the BW as a storage only, modify the drain to also use a hose to fill the regular tank. As to food grade, not sure what the difference is in plastic.

[Overland]

My thought was as a supplement only. As for the “poop” hole, if the tank is removable I could seal it and reinstall. Do not intend to connect the two tanks, use the BW as a storage only, modify the drain to also use a hose to fill the regular tank. As to food grade, not sure what the difference is in plastic.

 

Some plastics will leach things into the water that you don't want to drink. I believe if the black tank is HDPE plastic, then it's safe. I used to have a link to the manufacturer Oliver uses, but I can't seem to find it - maybe someone else has it, or you can call Jason Essary at Oliver. On the other hand, I believe some dyes will leach into the water, so even if the tank is HDPE, then the black dye might leach. Best to call the manufacturer to see.

 

Or you can be like us and not use the onboard water for drinking or cooking - only dishes, showers, etc.

 

If you don't connect the tanks, then you'll want to add an overflow/breather to the black tank so that it will fill and drain easily.

[John E Davies]

Yep, I was talking about converting the black to fresh in that thread, but I have not got anywhere with it yet. The tank should be fine for potable water, I think it is ABs, and the only code issue is that waste and potable systems cannot be interconnected. Thus you won’t find a manufacturer who will do this during or after production.... it would be up to the owner.

 

It should gravity feed the main tank since it sits several inches higher, so other than reconfiguring the venting system (you must disconnect and cap the existing big vent line at the tee under the bathroom sink) and adding a new vent/ overflow, there won’t be a lot to the conversion.

 

Go ahead and do yours, post pics and a shopping list, and then I will do mine. The R&D is the tough part.

 

BTW, since I fixed the pickup tube in my main fresh tank so that I can use almost all of the capacity, I am not nearly as worried as I was a year ago..... that mod is now standard at the factory, so you will already have full use of your fresh tank.

 

John Davies

Spokane WA

[ScubaRx]

Does anybody know if the black tank has ever been removed?

[John E Davies]

Does anybody know if the black tank has ever been removed?

 

I don’t think you would need to remove it to modify the fittings, but the factory can tell you how may hours are needed, and the difficulty level.

 

John Davies

Spokane WA

[Overland]

Second, Oliver cuts a hole in the top of the tank since they’re convinced you’ll want to poop in it one day, so you’ll have to repair that.

I need to correct myself on that - the hole I was thinking about is in the fiberglass floor, but on our trailer at least, there's no hole in the tank itself.

 

The black tank is, however, already connected to the drain, which in turn is connected to the grey tank drain, so it seems like there might be a hygiene issue there to deal with.

[danielewilderman]

Is it possible to use the black tank for the liquid which the compostin toilet collects seperately?

[Rumline]

Is it possible to use the black tank for the liquid which the compostin toilet collects seperately?

 

That's what I would want to do if we got the composting toilet. It shouldn't be too hard to connect the urine receptacle to the black tank by way of a pipe. But would it need some sort of flapper so the toilet doesn't become the vent?

[BackofBeyond]

Kind of defeats the purpose of the Composting head, for me anyways. Its not a big deal to me to empty the urine container. I would prefer that over all the trouble to empty with a hose and such. Once I have my OEII in hand, I'll take a look at the black tank and its possibilities. Probably just leave it alone for the interim.

[Rumline]

You still have to use a hose to empty the gray tank. IMO I'd prefer that vs. carrying a tank of urine through the campground, truck stop, etc every day or two.  But to each their own; to me the benefit of a composting toilet is saving water while boondocking and not having to deal with raw sewage. If #1 and #2 are kept separate, each are very manageable.

[Overland]

Yeah, carrying a giant bottle of urine to a public toilet isn't a glamorous affair, but you get used to it. I believe the toilet already has a flap of some sort so as long as the line to the black tank is fitted to the urine tank, it shouldn't vent any differently. I think the trick would be fitting a disconnect of some sort since you have to remove the toilet in order to empty the compost. Perhaps a short length of rubber hose that could be pulled off would be the way to go, or maybe garden hose fittings would work.

 

I say go for it.

 

[danielewilderman]

Perhaps the gray tank and black tank could be directly connected, increasing your gray water capacity substantially, therefore decreasing the frequency of emptying?

[John E Davies]

You could plumb the pee tank into the 18 gallon black tank, sure. Maybe. Somehow. How do you plan to clean the hose when it plugs up?

 

The Natures Head tank has to be cleaned every three or four fills since it starts to get crusty with hard yellow mineral deposits. Soaking for an hour with a high concentration of powdered laundry soap in water gets it out easily. Maybe you could run a long pipe cleaner through the hose.... just watch your eyes!

 

If you want to fill your black tank with urine, you need to be sure to always have some fresh water in there to start, plus a way to deodorize it. Normally you put half a cup of vinegar in the clear pee tank to kill the odor.

 

I don’t see the point of this mod whatsover, but go for it if you must.

 

I use a garden hose to drain my gray tank, I leave the big stinky at home.... and I am completely unembarrassed to carry around a full pee tank.  Nobody who sees it has a clue about what is inside.unless they see me inside a stall pouring it down a toilet. I do not usually have company in there.

 

John Davies

Spokane WA

[John E Davies]

Perhaps the gray tank and black tank could be directly connected, increasing your gray water capacity substantially, therefore decreasing the frequency of emptying?

 

I don’t think so, unless you have a shutoff valve between them. The black tank is substantially higher up and would gravity drain into the gray tank, and the excess waste water would vent out onto your bathroom floor, and possibly onto the main floor.... Gross.

 

Connecting black to fresh to give you nearly 50 gallons of potable water makes a world of sense, but I never saw any need for extra gray capacity. But I can dump my gray water using a garden hose under some shrubs, in many of the places I go.

 

John D@vies

Spokane WA

[Bikerabbi]

On 5/4/2018 at 5:48 AM, Rumline said:

You still have to use a hose to empty the gray tank. IMO I'd prefer that vs. carrying a tank of urine through the campground, truck stop, etc every day or two.  But to each their own; to me the benefit of a composting toilet is saving water while boondocking and not having to deal with raw sewage. If #1 and #2 are kept separate, each are very manageable.

Slightly off topic and old,  thread, but I want to ask if your 2018 Ford Expedition handled the trailer up steep hills and if you liked how it handled the load.   

Thanks,

Gabriel

[Patriot]

1 hour ago, Bikerabbi said:

Slightly off topic and old,  thread, but I want to ask if your 2018 Ford Expedition handled the trailer up steep hills and if you liked how it handled the load.   

Thanks,

Gabriel

Gabriel,

 @Rumline  profile shows he sold his Oliver and has not been active here on the forum since May of 2020. 
Maybe someone else might chime in with an answer. 

 

Patriot🇺🇸

 

[Bikerabbi]

On 8/4/2023 at 1:33 PM, Patriot said:

Gabriel,

 @Rumline  profile shows he sold his Oliver and has not been active here on the forum since May of 2020. 
Maybe someone else might chime in with an answer. 

 

Patriot🇺🇸

 

Thanks...