MSD type II tank

Discussion in 'Boat Design' started by ErikdeJong, Nov 1, 2012.

  1. ErikdeJong
    Joined: May 2012
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    Location: Halifax

    ErikdeJong Junior Member

    Hello All,

    these days it becomes more and more difficult to pump the toilet straight overboard. Holding tanks are an option, but because of my draft, I can reach the pump out stations only with extreme tides.

    Therefore, I was looking into an MSD type II installation, it basically is a series of three smaller holding tanks in serie. The first one is used to break down any solids with the help of bacteria, the second one is used as settling tank and the third part is where the chlorinating takes place before the left overs can be pumped out overboard.

    These units are for sale as a standard tank, but they manage to charge $4,500+Tax for these things. I'm fairly convinced that it is just a bunch of plastics, two bulkheads with small holes and some pipes here and there.

    My current holding tank is the same content as a standard MSD tank for 6 persons. And it is already divided in three fairly equal parts. Would it work to make just a few connections to my existing built in tank and get it to work? Or is there something fancy in the MSD design that I'm missing?
     
  2. michael pierzga
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    michael pierzga Senior Member

    You have my sympathy. These regulations, when applied to small craft are onerous and unjustified.

    A Black water tank requires correct planning and execution. Be particularly aware of your tank vent system or your boat will stink.
     
  3. ErikdeJong
    Joined: May 2012
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    Location: Halifax

    ErikdeJong Junior Member

    Hello Michael,

    Thanks for your reply. The tank as it is, is working fine, also at sea with severe weather. No risk of sinking there.

    The tank has been in use for several years now. The problem is that I have to sail 40 miles to legally dump it overboard OR I need to wait for extreme high tide to reach any of the pump out stations. The current capacity is enough for a week, but I do not have time to go to sea every week nor is there an extreme tide every week at a convenient time (during daylight).

    I have no room to expand the tank capacity more than it, so I need to look at a "processing plant" from which the residue can be legally dumped at any place. the MSD type II is such a thing.

    Here an example:
    http://www.skimoil.com/marine_sanitation_device.htm
    I find $4,500 for such a simple structure pretty steep. I think there is not much more to it than a rectangular box divided in three with some hoses and a chlorinator. The bacteria's can be added by flushing them through the toilet once in a while. Should be easy to make it a D.I.Y. project shouldn't it?
     
  4. michael pierzga
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    michael pierzga Senior Member

  5. kapnD
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    kapnD Senior Member

    The three tanks have specific functions, all scientifically designed to do certain jobs, even the shape of the chambers is vital to the way they work. Forced aeration also plays a part in the processing, so in short, no, your simple three compartmented tank will not do the same thing, though it will be somewhat effective if the waste is forced to flow over the top of the baffles.
    Don't get to feeling too lonely about the cost of processing sewage, it is not limited to yachts. My home sewer fees rise dramatically lately. They are based on water usage, so the only way to keep the bill low is to use less water.
    Maybe if you cut down to one meal a day???
     
  6. michael pierzga
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    michael pierzga Senior Member

    JeJeJe...one meal a day !!

    I propose three good meals and then behave like a seagull. Eat , shuffle out on deck , perch up on the lifelines...*** facing the sea.. let out a warning SQUALK, then PLOP or BLAST overboard. Much more civilized ! Careful with wind direction.

    What I really despise about sewage handling on a yacht is the Prime real estate that must be sacrificed in the bilge...down low, near center line...to make and system function correctly.

    Oh well.....and good luck with your poop system
     
  7. michael pierzga
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    michael pierzga Senior Member

    Oh and since I just got back to a boat and it stinks inside , I thought Id pass on a helpful tip for your plumbing. Normally a toilet is wet. This water keeps the stink in the tank from venting into the boat. If the bowl goes dry in bad weatherof from non use..STINK.

    To help with this problem I install duck bill one way valve from SEALAND in the toilet outlet line. Close to the toilet.

    If the toilet goes dry, these duck bills do a good job at keeping the stink air from breathing into the cabin via the toilet exhaust line. Not perfect because after time they deform...but pretty dam effective.
     
  8. rasorinc
    Joined: Nov 2007
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    rasorinc Senior Member

    In the US I believe the Coast Guard must approve all self treating systems and all methods of disposal and are very strict about. Cannot not say anything Re: Canada.
     
  9. viking north
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    viking north VINLAND

    Erik wouldn't it be alot less expensive to install a mancerator pump in your holding tank's out line. This would allow you to pump uphill to the dump tank using a 1 1/2in. hose. Many motorhomes are now making use of this marine application.
     
  10. marshmat
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    marshmat Senior Member

    I'm not sure about Halifax, but there are an awful lot of areas- my part of the Great Lakes included- where it's "no discharge, period". By the time you get to an area where it's legal to discharge MSD-treated wastewater, it's likely also legal to dump raw sewage overboard. Hence why these things are so rare.

    It might be worth looking at composting / water-separating systems. Some work, some are finicky, some are junk, but (at least in theory) they do solve the dumping-overboard problem.
     
  11. viking north
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    viking north VINLAND

    Here in Atlantic Canada (verses maratimes which excludes Newfoundland) I recall (I stand corrected ) small craft untreated raw sewage can be dumped beyond the 12 mile limit. My new build will include a holding tank with mancerator pump discharge which i can simply empty ( at my dock) into a 2 wheel RV black water cart/tank. This I can empty into my homes septic system which is equipped with a cleanout cap for such. Mancerator pumps and RV septic carts run about $200 a piece.
     
  12. michael pierzga
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    michael pierzga Senior Member

    I believe thats the law everywhere. ..this is how I behave in many many countries.
     
  13. viking north
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    viking north VINLAND

    Michael -- first I alpolgise for my rashness on the other thread, I have edited a retraction there indicating so. It was a result of misreading your prev. post plus this is not my style. And yes i thought the 12 mile was the magic number. My prev. craft manually pumped raw sewage directly into the ocean. On this build I am using an electric toilet as well as the mancerator pump out. I just got sick and tired of having to demonstrate then unplug heads operated landlubbers.
     
  14. Ike
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    Ike Senior Member


  15. bpw
    Joined: May 2012
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    bpw Senior Member

    I would guess a lot of that $4,500 cost is covering the expense of getting the system certified.

    Even if you built your own and it works great, how will you prove it?
     
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