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Thread: Post Toilet

  1. #1

    Default Post Toilet

    Hi. I've already been to composting forums and they do not have a clue on PVC. I'm looking to build a liquid/waste separator, inline, for my composting toilet. I've seen this before, some years back, and now I'm such it's all controlled, bundled into a book and ready to sell. I don't have the money for this so it will not happen.

    I just want to baffle the water leaving the toilet into a separate line and drop the solid into the drum. I can screen the liquid line and that's easy but I need a lever or stop gap of sorts until the water leaves the system. Actually gravity alone should take care of it without intervention. Even if some water does make it through, my heat ventilation system with fan will evaporate that.

    If anyone has anything on this, it's welcome to hear it.


  2. #2

    Default PVC Ball Valves

    I've been searching ball valves using gravity and haven't found anything yet. The only thing I can think of so far is to build a box in advance of the 4" pvc pre-drum and post-toilet. In this box I would put a thick wire mesh on a small levered platform of sorts that would hold the waste until the liquid passes but I'm trying to figure out how to automate this from the toilet and using gravity.

    I've already been to the physics forums. They don't want to talk about eco waste and gravity in the same sentence I think.

    I thought of getting an rv toilet with a floor levered ball flush and connecting to that mechanism.



  3. #3


    Looks like what you're looking for is a method to build a waste treatment system. The large plants are quite simple. Waste goes into a pit which is pumped into an anaerobic methane generator/digester where the solids settle to the bottom, gas goes out the top and the liquid flows out to a protein skimmer for floating matter. This liquid is sprayed over large pourous gravel/rocks for aerobic digestion to take place. After all of this takes place the liquid effluent leaves the treatment facility and is frequently cleaner and safer than the town's drinking water. The scenario is not totally correct but is fairly close.... RJ/b.s. microbiology/ from course in sanitary microbiology/Auburn University, an elective for microbiology and civil engineering majors. The similar principle is used for lagoons on hog farms which employ methane generators/digesters as part of the waste treatment.
    Last edited by Randyj; 12-31-2006 at 03:56 PM.

  4. #4
    Plumbing Contractor srdenny's Avatar
    Join Date
    Sep 2004
    SF Peninsula


    Here's a site that might be of interest to you:

  5. #5
    DIY Member TPA's Avatar
    Join Date
    Mar 2006


    A lot of this depends on how your composting toilet works. Most composting toilets I've seen (which aren't many) are designed to have liquids go down them. I know the solid waste has water within it, but I'm under the impression that you need water to make the composting action happen.

    Trying to filter out the liquids from the solids is going to produce a device which will be maintenance-intensive, due to the semi-solid nature of the solids. I'd imagine a mesh or series of holes will get clogged and require frequent cleaning.

  6. #6


    Alabama now requires a filter at the effluent end of the septic tank to keep the solids in the tank for anaerobic digestion so the liquids will go out to the leach field lines. A similar mechanism sounds like what you should be looking for. The tank also is baffled to keep a large portion of solids on the inlet side of the tank.


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