Sewage in pipe before septic

Discussion in 'General Plumbing Help' started by Djb633, Jun 16, 2019.

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  1. Jun 16, 2019 #1

    Djb633

    Djb633

    Djb633

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    I plan on putting a two piece bath in my garage, it will be around 100' away from my septic tank. It won't be used often and I was wondering if might be making myself a lot of headaches. If someone has a crap and flushes, the sewage won't make it all the way to the septic tank before the pump shuts off. Now if the bathroom is not used for another couple of weeks or maybe a month will the sewage solidify and clog the pipe. If my math is correct the pipe volume will be around 16 gallons and at 1 1/2 gallons a flush that's a lot of flushes before it makes it too the septic.
    Any thoughts?
     
  2. Jun 17, 2019 #2

    Diehard

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    I don't believe the total volume of the pipe is a factor.

    A common recommendation that I have seen says, "If your 100 feet away, than your septic inlet needs to be between 3 to 7 feet deep with five feet giving you a nice 5 percent(1/2"/foot) grade. As for distance, the rule of thumb is to put clean-outs at just under twice the distance you can reach with a snake."

    There is a maximum slope which would cause the liquid to move too fast and tend to leave the solids behind. Apparently this is not thought to be it.

    I have no first hand experience with this design concept. It's just all I could find in by limited research.

    If someone tells you it's a certain way or not a certain way, make sure you get the reasons.

    I'm sure there is more detail info available along these lines(I know I have seen some along with the research data on the capabilities of low flush toilets.). It's just time consuming to find it. I believe ASPE is a good source. That's the American Society of Plumbing Engineers.

    How far is it to the existing drain line which is running from your house to the septic tank. Maybe that's where you should tie it into, if it shortens the run.

    Or maybe just provide a holding tank that can be manually emptied periodically.
     
    Last edited: Jun 17, 2019
  3. Jun 17, 2019 #3

    Djb633

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  4. Jun 17, 2019 #4

    Djb633

    Djb633

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    Hi
    I guess I should have gave you more info. My cottage doesn't have a basement, it is about 4 blocks high, the plumbing hangs underneath with an insulated skirt around the cottage , i do plan on joining to my main 4". The 4" line is higher then where the pump is going to be located by about 5' so when I flush the sewage will sit in the pump housing until the float turns the pump on. Now I'm not sure how many flushes this will take but it still won't be enough to pump the sewage all the way to the 4" main line where gravity will take over and drain it to the septic bed. So..... will the sewage solidify in the 2" line from pump to 4" main line.

    Thanks
     
  5. Jun 17, 2019 #5

    frodo

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    Djb

    set the float in the holding tank to not come on till enough water is in the tank
    to wash the 2'' line out.
    2.jpg
     
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  6. Jun 17, 2019 #6

    Diehard

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    Oh quite different scenario.
    So you're pumping uphill and the pipe volume will be around 16 gallons.

    So in the case of the suggestion to set it so 20 gallons will pump, only 4 gallons of that will actually reach the gravity line. That 4 gallons may be enough to clear the solids. ??????
    But in any case, your concern as to "will the sewage solidify and clog the pipe in a couple of weeks or maybe a month of non use." I'd venture a guess that with the pipe staying full of liquid, chances are it wouldn't solidify.

    Now as far as you "wondering if it might be making myself a lot of headaches." Only you can answer that question. Personally, I would simply rely on one of those camping toilets. And for the other piece of "a two piece bath", I'd make that a grey water waste and dump it on the ground somewhere.
     
  7. Jun 17, 2019 #7

    Djb633

    Djb633

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    Thanks for everyone's replies,
    I hadn't thought about setting the float higher. I was thinking of getting the Liberty pro380 side discharge system 24" x 24" with a 41 gallon capacity so I guess it won't come on until it can pump enough to make it to my main drain pipe. I guess there will always be 16 gallons of mostly fluid in the line that I will have to blow out before winter comes.

    We are not allowed grey water waste where I am.
     
  8. Jun 17, 2019 #8

    frodo

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    yes there will always be fluid in the line,
    that is just a fact in a pumped line
    it is the reason for the check valve
    a bit of information you did not provide
    what is the difference in the elevation at the pit exit pipe and the septic tank inlet?
     
  9. Jun 17, 2019 #9

    Djb633

    Djb633

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    the difference in elevation from pump outlet to septic tank inlet is about 1'- 2'. But I can't go straight from garage to septic tank because the cottage is in between them. That's why I was thinking of going under the cottage and then join the 4" main drain.
    I could also come up under the cottage and run it the 36' length with a slop and join the main drain where it drops to go under ground to enter the septic tank. The problem with that is I use this space for storage and the pipe may get damaged.
     
  10. Jun 18, 2019 #10

    Mikey

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    I assume you're using a macerator pump of some kind; the manufacturer of that pump might be able to give you some guidance.
     
  11. Jun 18, 2019 #11

    Djb633

    Djb633

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    I'm not using a macerator pump, they are not recommended for septic tanks because they grind up everything too fine that the particles can float over the second chamber of the tank and into the bed.
     
  12. Jun 18, 2019 #12

    Mikey

    Mikey

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    Same reason, I suppose, that disposers are discouraged. Most of the high-tech systems I've seen have filters in them (that need to be cleaned, periodically), but the result is a very high-performance waste disposal system. Also usually aerobic, I think.
     

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