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Treating Waste In RV Cassette Toilets and Composting Toilets

December 10, 2019

Treating waste in RV Cassette Toilets and Composting Toilets Unique Camping + Marine

Key Points:

  • Portable cassette and composting toilets can be a useful and effective alternative to the full-sized holding tank systems typically found in larger RVs and trailers. 
  • Cassette toilets and composting toilets do have some downsides (see below) and require regular, hands-on maintenance. 
  • A cassette toilet is composed of a toilet bowl that has been permanently installed in your camper with a removable tank that can be easily removed and dumped. 
  • A composting toilet works by keeping solid and liquid waste separate. Solid waste remains dry and is broken down by a natural composting medium (normally composed of ground-up coconut husks, peat moss, or sawdust). Liquid waste is dumped down out. A ventilation system directs odors out of the RV. 

As the world grows increasingly busier and more fast-paced, many have chosen to reject this notion of over-stimulation and instead have opted to embrace a more simple way of living. For many, this is the exact reason why they bought a camper in the first place. It's a way to escape the rat race! If this sounds like you, as you disengage more and more you may find yourself looking for simpler, tried-and-true alternatives for your RVs waste water treatment. For many, a portable cassette toilet or a composting toilet fits this bill perfectly.

As modern nomads move towards living in vans, RVs, trailers, or DIY busses grows, portable camping toilets are becoming a widely used alternative to public restrooms. Cassette toilets and composting toilets are, for many individuals, convenient and easy to use, and they provide a good second option to the full-sized holding tank systems typically found in larger RVs and trailers. If you are looking for how to treat waste in a standard RV toilet, click here.

In this article, we’ll be diving into what portable cassette toilets and composting toilets are, the benefits and drawbacks of using a camping toilet.

Cassette Toilets

A cassette toilet is essentially a toilet that has been permanently installed in your RV with a removable black tank - often accessible from the exterior of the vehicle. Cassette toilets can be installed in an RV, van, or trailer and the black tank can be dumped by hand by simply removing the tank and dumping it out in an appropriate receptacle or drain.

A cassette toilet is composed of the actual toilet bowl (installed inside the camper), the removable black tank which is normally accessible from the outside of the camper (normally about 5-gallon capacity), and a water source. After you go to the bathroom in a cassette toilet, a valve on the toilet can be engaged to allow waste to flow into your black tank where it will be stored until you remove the tank and dump out the contents. Many systems have a light that indicates when the black tank is full. 

There are some benefits of using cassette toilets over a traditional full-sized holding tank system:

  1. Simple and easy to use.
  2. More options for dumping.

However, there are some substantial downsides to using a cassette toilet:

  1. Because of their construction and water usage, cassette toilets are some of the most likely types of RV toilets to incur problems.
  2. One of these problems is nasty odors. 
  3. To control odors, many people will use traditional RV holding tank treatments. 
  4. Since you must dump a cassette toilet’s black tank by hand, you are very up-close and personal with your waste! 

Cassette toilets are very compact and have very small ventilation systems and waste storage tanks. As a result (seen in the drawback list above), it takes more upkeep to control strong smells and solid waste. Without consistent treatment, odors will build up very quickly inside the waste storage tank. 

If you choose to go the cassette toilet route, we strongly recommend that you not use chemical treatments to control odors. Chemical treatments merely mask odors; they do not eliminate them. Moreover, some of these chemical treatments contain fragrances that are more caustic and nasty-smelling than the waste itself! Additionally, some chemical treatments (particularly those that use formaldehyde) are actually dangerous to your health. Formaldehyde has been linked to numerous severe diseases and health problems, including ALS and cancer (learn more about this here.)

The truth is that cassette toilets can become very stinky if not treated correctly, and it takes a lot of due-diligence to control these strong odors. The best option to mitigate odors is often to consistently dump your cassette toilet to prevent residue build-up and odors. The key is to not let waste stagnate inside your cassette toilet.

Composting Toilets

Now that you know what a cassette toilet is, and how to treat them, we’re ready to dive into composting toilets. 

At its most basic level, a composting toilet works by keeping liquid waste and solid waste separate. Solids flow into one container, and liquids flow into another container. Both tanks are removable. In the solid waste container, a composting medium (many people use ground-up coconut husks, peat moss, or sawdust) helps to break down the waste. Furthermore, a fan draws air over the solid waste and out of the RV, drying out the waste and forcing odors out of the RV. The liquid is captured in a separate container that can be dumped out.

Composting toilets have some benefits: 

  1. They use no water and produce no water.
  2. Because it uses no water, there is no plumbing that goes to or from a composting toilet. 
  3. Like cassette toilets, there are more options for dumping.
  4. Composting toilets do fairly well in controlling odors. 

Nevertheless, there are drawbacks to using a composting toilet:

  1. You must keep the solids and liquids separate. 
  2. Like cassette toilets, since you must dump it by hand, you can be very up-close and personal with your waste! 
  3. Occasional urine odors
  4. They require a moderate amount of maintenance and work

To be sure, RV holding tank treatments are not always necessary in a composting toilet (a composting toilet should do most of the work on its own). However, if you are dealing with odors from urine, bacteria holding tank treatments can help mitigate odors.

When temperatures drop below 50° Fahrenheit, the naturally-occurring aerobic bacteria in a composting toilet will begin to slow down in their biodegradation process. If the temperature remains low for an extended period of time, the bacteria may die off. This will leave you with the very smells you were trying to avoid by using a composting toilet! It is incredibly important to keep your composting toilet from getting too cold.

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Final Thoughts

Regardless of whether or not you choose to go with a cassette toilet or a composting toilet (or stick with a full-sized system), we hope this article has proved helpful by showing you how these toilets work, their pros and cons, and our recommendations!

If you have any questions, please contact us at We are always more than happy to help you!

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