Need suggestions for a custom black water tank

[adam88]

I am in the process of building a camper and I am wanting to include a black tank. I had previously planned to go with a cassette toilet or composting toilet, but I have decided against that for various reasons. Instead I am going to use an electric macerating toilet (marine style) that will send the waste to a 50 gallon black tank. I have this part figured out.
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What I want to do from there is... I want to hook up a garden hose directly to the tank and be able to flick a switch and pump all the black tank out through the garden hose up to 100 feet away. This way I can dump the sewage anywhere, such as inside a house into the toilet, or to a remote outhouse. Then, finally, I'd like the switch to be a "rocker" style switch... push it up, it pumps out. Push it down, it reverses the flow of the pump. This way, when I am done emptying the black tank, I can fill a small 5 gallon bucket with water, put the hose in it, flick the switch the other direction, and backflush the hose to clean it.
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I will have an inverter on board and lots of battery power (110v). Does anyone have any recommendations on a pump that would be suitable for this? It does not need to be a macerating pump, because all the stuff in the tank will already be chewed up by the electric toilet. I'd like something that can pump very fast like 10 gallons a minute or more so I can empty the entire tank in about 5 minutes. Also, if anyone has any thoughts on why this might NOT work please let me know. To me it seems like the ideal solution but maybe there's something I am not seeing.
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Thanks!
Adam

 

[e60ral]

Is there even a pump that can both push and pull through 100' of garden hose? Also it will have been macerated but it still won't be fluid you can easily pump through a small hose, it will still have some pieces in it.

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[Ramdough]

I think you should consider a different plan. Pumps generally don't have a way to reverse flow. You would need two separate pumps with valves. It would be easier to dump water into the toilet and flush it out that way. Also, you would need a pretty strong pump to push sludge through a 100' garden hose. That is going to add weight. Also, disconnecting a garden hose will most certainly spill black water where you don't want it. I have never disconnected a hose without spills and drips.


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[Joe917]

High pressure s#^t through a 100" garden hose, what could go wrong?

 

[Ramdough]

High pressure s#^t through a 100" garden hose, what could go wrong?

Hahahahhahaha....... I think you said it best.


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[e60ral]

It looks like pumps are already made that have fresh water flush capabilities, for example: http://www.campingworld.com/shopping/item/flojet-rv-waste-pump-kit/26125

If you don't get one that is pre-made for this, I would still use a pump with a macerator to prevent clogs from anything that may not be fully macerated

 

[Ramdough]

Have you thought about using a composting toilet like a Natures' Head or Separrett Villa?

I was in a similar dilemma about what to use and I chose a Separrett Villa because it was so much less to mess with. You still have a Grey water tank that your urine feeds into, but no black water tank. The Grey water would be easier to pump or dump and be less nasty. Plus, as you use your sinks or shower, you are diluting your tank. Some places you can dump Grey water just on the ground as well. You have to empty your solids compartment, but that is not heavy and you can go a while between dumping.

In my opinion:

1. They add less weight to your rig
2. Do not use water
3. Easier to plumb (if any is even required....depends on model).
4. The compost can be dumped many places easily or buried.
5. No need to find a dumping station (unless you are in a park that prohibits Grey water dumping).
6. Depending on black water tank size, you may actually go longer without dumping.
7. You still have to get rid of poop, but instead of it being a soup of stinky nastiness, you are getting rid of mostly dehydrated poop (depends on the model of toilet).
8. No chemicals needed.

Everyone has an opinion about what composting toilet is better. There is a thread I posted to on the reasons I picked the Separrett over the Natures Head.

They have generally had good reviews. You might want to look into them.


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[java]

If your set on that plan, a marine discharge pump sounds like what you need. https://www.fisheriessupply.com/pumps/macerator-and-waste-pumps I would use pressure rated hose if I was doing it though....

Other options https://www.fisheriessupply.com/pumps/macerator-and-waste-pumps nothing seems to be more than 5GPM though

 

[Ramdough]

If you are interested..... the composting toilet thread I mentioned is here.


http://forum.expeditionportal.com/threads/155039-School-me-on-the-topic-of-toilets-




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[Paul Davenport]

I like the concept, but 10 GPM is a lot of flow. Often pumps at or over 5 GPM are listed as wash down pumps, suggesting they have a bit of pressure through a garden hose. I'm not sure you could discharge that into a toilet without significant clean up from splash. If your plan comes to fruition I'd test that flow with fresh water before committing and buying the pump.

Just my .02

 

[CL10473]

What about something like this (just translate it).
http://www.hrz-aqualizer.de/mini-klaerwerk-pages/funktionsweise.php

 

[DiploStrat]

Another Vote for a Composting Toilet

The Howes (http://www.travelin-tortuga.com/Travelin-Tortuga/) have taken their US Class C Tiger to more than 55 countries. they use a conventional black tank and have this to say:

… We also use and recommend a macerator pump for dumping our tanks. Campgrounds with US style dump stations are rare outside of the US and Canada. As a result, travelers often end up having to dump in fields, down sewer grates or in facilities designed for cassette toilet systems such as those used in European motorhomes. With a macerator pump, you are only dumping liquid and we feel it is much easier to accomplish emptying your tanks in any setting with a clear conscience. In more urban settings, the macerator allows you to pump waste 100’ or more to reach a suitable receptacle

Bottom line, it would appear that you do not need any kind of special pump to get a 100 foot range. As far as I know, their pump is an off the shelf unit as might be sold by Camping World or other RV shops.

 

[pugslyyy]

We have a Sani-Con / Thetford 70427 with 4 21-foot retractable hoses. In the US we normally just have one of the hoses connected because it is more than enough length.

If I were starting from scratch I would not have a black tank at all, but what we have works just fine.

 

[MOguy]

If you can park your camper higher than the point you want to dump into you will need no pump.

However I can't imagine dragging a hose through my home to the bathroom and trying to dump 50 gallons of black water into my toilet that has a bowl that only holds a few gallons (esp at 10 gallons per minute). How could anybody think that is a good idea?

If it is our your own home look for an exterior clean out and let it flow down that. It will be at ground level (gravity) and you will not have to pump crap through your home.

As far as pumping back into the tank? Why would you pump black water back into your camper? Just dump the clean water back into the camper toilet and repeat. 5 gallons of water will not be able be enough to clean out a 50 gallon tank and 100 feet of hose.

And use a hose bigger than a garden house. Sewer pipes are bigger than fresh water pipes for a reason. Even if you blend your crap up it still won't flow like fresh clean water.

As far as a 100' hose, how would you plan to store 100' of black water flowing hose? Even if you do run clean water through it is still a 100' of dirty dirty hose.

 

[Ramdough]

I reiterate, I think you would be happier in the long run with a composting toilet. Less crud to mess with, less plumbing, less to store.....etc.

I picked the Separrett because literally you poo in a decomposing bag. The toilet dries it out for you and sucks the odor away. Then can toss the bag when you need to every 3 weeks.

With all of the reviews I have looked at, I only found a few negatives and I believe those people were doing something wrong and letting insects in.

Ultimately it is a personal choice. I am curious what you end up going with.


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