Activated Carbon Odor Killer Filter for RV's and Boats




About: I'm a retired mechanical engineer, woodworker, boater, and inventor. Now I'm getting into wood turning, and have found that all my wood projects need not be flat and square.

If you have an RV or a boat, you likely have a holding tank for sewage. If you have a holding tank, you have a problem with odor.  Right? It's the price we have to pay for having some of the necessary comforts of home in our RV or boat.

These holding tanks all have a vent, or they would explode, and if you thought odor was a problem.... 
Activated carbon, available as aquarium filter media, will remove the odor from vent gas.

I built a home made odor killer for the holding tank on our boat which solved the problem.

Step 1: Parts

I used these parts:

2" PVC pipe, 24" long
2" fittings for each end, the glue-on type. These fittings need to reduce down to a size where you can slide a length of clear vinyl tube over it. So, I used fittings that reduced town to a short length of 3/4" PVC pipe so that I could slide 1" vynl hose over it tightly.
1" vinyl tube
Activated carbon that can be bought at a pet store
Fine screen, like window screen, of fine wire screen.

Step 2: Add/glue Screen Into 2" Fittings

You will need to cut the screen into two  2" (or so) circles and glue them into the 2" fittings. This will keep the activated carbon inside the filter.

Step 3: Glue One of the Fittings to End of 2" Pipe

One fitting, with the screen inside it, is glued permanently to one end of the 2" pipe. In this photo you can see where the fitting reduces down to the 3/4" nipple extension.

Step 4: Fill With Aactivated Carbon.

Fill the tube FULL of the activated carbon. If you don't have enough carbon, cut the pipe shorter! The pipe must be full.
When I took this photo with my old cheap cell phone, you could see the carbon up to the top of the pipe.

Step 5: Install

Tape the other fitting on so you can remove it later for replacing the activatd carbon. Use duct tape, of course.
Use the vinyl tube to make connections to tank vent and outside exit vent. You might want to use hose clamps.
The 1" vinly tubing (hose) is the size that fit the pipe fittings on my boat. Your sizes may be different.



    • Weaving Challenge

      Weaving Challenge
    • Tape Contest

      Tape Contest
    • Remix Contest

      Remix Contest

    11 Discussions


    6 years ago on Introduction

    I made something similar years back to replace pricey SeaLand ones.
    Working on a charter boat with large tank and vertical pipe, I broke down
    and purchased a household type after weighing in costs for the pvc parts to make one.
    Also have found kitty-litter with activated charcoal works

    2 replies
    Bill WWsodiumcanine

    Reply 6 years ago on Introduction

    Thanks for the comment.

    My general approach is "why buy one if I can build it." But on occasion use common sense and economics when I have to.


    sodiumcanineBill WW

    Reply 6 years ago on Introduction

    If I would of had the time, I would have thought it up and built it like the last one
    Stinky charter boats do not get tips. Hooray for "Fart Filters"!


    6 years ago on Introduction

    Very good project, Bill!

    I am thinking to make something like this. Here the activated carbon costs about 10 dollars/Kg. Maybe I will do a try using simple vegetal coal.

    4 replies

    Reply 6 years ago on Introduction

    plain grilling charcoal works well.. just don't use the easy lighting kind.. to control odors inside cars and closets in damp climates


    Reply 6 years ago on Introduction

    Thanks for the info, I8nite. I bought 2 kg of the activated carbon, but before making the filter I have to finish a hinged bracket for LCD TV.

    I will try plain charcoal too.

    Bill WWl8nite

    Reply 6 years ago on Introduction

    Thanks -

    I used the granular type so that it filled the PVC tube nicely.


    rimar2000Bill WW

    Reply 6 years ago on Introduction

    I bought 2 kg of that activated carbon (approx 6 dollars/Kg), but before making the water filter I have to finish a hinged bracket for LCD TV.