Waste Holding Tank Aeration

[Bacchus]

I have read many of the black water tank posts but didn't see any reference to aeration via bubbler. Does anyone have any experience - good or bad - w/ bubbling their holding tank?
I understand and absolutely agree w/ HeadMistress's comments - on a previous Carver Riviera w/ a 40 gal holding tank I read the book and successfully eliminated foul odors by adding a second - short & straight - vent line. My current Mainship 34 Trawler provides many challenges to doing anything similar and I'm convinced the problem is insufficient air. The tank is difficult to get to and runs would be longer than desired even if I could get another vent attached.
I've seen commercial bubbler systems but thinking about building one myself to try.
I have an unused 12v circuit and plugged tank discharge from a previously removed macerator pump. Figured it wouldn't be difficult to install a bubbler tube through a ball valve ( so tube could be removed and valve closed if it needed any maintenance) and wire up a pump / timer.

Wondering if anyone has tried this or similar???
Thanks

 

[FF]

Bubblers are common on the euro charter scene , where a 30 might stern tie next to a 60 (METERS!) and not want the black tank vent rising up for the 60 to smell.

A home brew should work , perhaps some version of a fish tank bubbler.

Since it will be a 24/7/365 unit, quality and low power requirements are a given.

Yes it does better than poisoning the waste .

 

[ulysses]

There are two types of bacteria at work "digesting" waste water. Those that need air and those that don't - aerobic and non-aerobic. A septic tank type system does not need air a municipal type system does. It all depends on what type of bacteria you want working for you. If you don't already have the ones that require air your local sewer treatment facility will provide you some. There are numerous campgrounds that have installed aerobic digesters in this area that only have seasonal use so they have a honey truck borrow some from our local waste water plant each year as they start operations.

 

[FF]

The charter tubs are not attempting to digest the waste . just to stop the STENCH.

 

[Tony B]

........ any reference to aeration via bubbler........... I'm convinced the problem is insufficient air. The tank is difficult to get to and runs would be longer than desired even if I could get another vent attached...............

I have a 36 DC Mainship. I don't know what your vent set-up is, but if it's anything like mine, the only way to get a straight vent line would be to make a hole in your roof and that is out of the question. Obviously, we had the same problem.
There are 2 main types of bacteria that attack and digest human waste. Aerobic which thrive in an air rich environment do not have a significant odor. The other type is anaerobic which thrives in a low oxygen environment and stinks like $hit. The type of bacteria that you get is from the environment you create - either airy with a good vent line or stagnant with poor ventilation. A bubbler should work great although not really necessary. If you have the air supply for the bubbler, that is all you need - just the air. I'm not sure if the agitation from bubbles would cause more odor by stirring thins up or less odor because the aerobic guys are working in a better environment, I'm sure if Peggy gets back on here she would have an answer and I would go with what she says.

Do you have the old Sea-land Traveller heads that look like they belong on RV's? The type with the pivoting flap?

I just put in a PuraSan Waste Treatment System with an electric toilet and that solved the problem for the forward head. A bit extravagant but since we live aboard, this eliminates our pump-outs and is worth it to me.

 

[Bacchus]

Tony
Mine is not the RV gravity flow but I am familiar w/ them for the "Land Yacht"
I have a Jabsco marine head & 40 Gal holding tank. I understand the aerobic vs anerobic and hence the reason to get the air in there.
I could not easily add another vent or even "fix" the one I have so decided aerating might be the best approach.
Looking at the Groco Sweet Tank and emailing an old poster on another forum I feel like adding a "dip" tube to actualy bubble vs only introducing air in the top of the tank is a small addition and should provide better results - small bubbles more surface area to promote the right growth. My contact provided the following based on his positive results...
"The amount of air exchange in the holding tank only needs to be quite low < 5cu.ft / hr. sufficient to remove the odors with fresh air."[/I]
I have a 12V aquarium pump ordered and will fab up the rest of the parts so I can insert a perforated tube in through a plugged drain on the tank - and bubble w/ the air pump. I may add a cycle timer reduce the on vs off time of simply shut dawn at night if noise is an issue.
Thanks for the inputs

 

[Tony B]

Don
It sounds like you got it all figured out. No reason that I could think of why it wouldn't work. I just never heard of anyone doing it on a boat before. Let us know how it works out.
Good luck and stay Warm. Beautiful country up there. I miss my snowmobiling.

 

[Alaskan Sea-Duction]

If your tank is smelly then forget all this expensive stuff and use this:

http://www.marinesan.com/Noflex-digestor-p/noflex.htm

 

[Bacchus]

Just updating an old thread as part of an experiment of forum software operation.
If anyone sees this ans isa interested in the outcome... the DIY bubbler has worked like a charm. Unfortunately I started using NoFlex at about the same time and haven't felt the need to see how much of the success was each independently... its working well and I don't mind a little belt & suspenders.
If anyone is interested in the detail or how I did it you can see my Bacchus website (in signature) in he projects section. https://dkloeber.wixsite.com/bacchus/projects-pg-2

I have more recently also figured out a way to get a near horizontal vent by running it forward under the FWD cabin bed to the bow area where the A/C & anchor locker drains are located. The side benefit is that if any smells are emitted they will be far away from dock neighbors. The other plus is that wind at the bow is not blocked by adjacent boats in slips so a better chance of getting air flow.
So far the 12V fish tank bubbler has been very durable and runs 24/7 during the NE season. When the bubbler finally gives out I will likely try the new vent alone and see if that is sufficient or whether I will replace the bubbler.

 

[CaptTom]

Thanks for (eventually!) filling us in. I have a couple of fish tank bubblers kicking around and have been thinking about this mod myself. Maybe now this will move it higher on the list.

 

[Comodave]

It really works well.

 

[SteveK]

Bacchus is the tube verticle from top down or?

 

[Bacchus]

Mine goes in horizontal at bottom. I abandoned the macerator discharge being inland / great lakes. I used adapters to get down to small size pvc tube (household sink tube). The original copper didn't survive.
I've seen others that added a top fitting and used a vertical tube with T at bottom. I dont think it makes much difference as long as you can get the air in.