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How to find the right Urine Separator Insert for your Composting Toilet


The 4 best Urine Separator Inserts for Composting Toilets


To build your garden toilet, holiday house toilet or mobile home toilet yourself

In this article I would like to introduce you to the most common Urine Separator Inserts for dry toilets.

Since I wrote this blog post last year, a lot has happened in the arena of ​​separation toilets, dry toilets and composting toilets.

And that’s good. It shows that the dry separation toilets are attracting attention as garden toilets and in ​​mobile homes and holiday houses, and that they are increasingly displacing the chemical toilet.

I have revised this article so that you stay up to date.

If the principle of the separation toilet or the dry separation toilet is not yet completely clear to you, take a look at this blog article.

This blog post is broken down as follows: 

  1. The principle of the separation toilet. How does a composting toilet actually work?
  2. Which Urine Separator Inserts are available? 
  3. Advantages and disadvantages of the various Urine Separator Inserts
  4. What should you pay attention to when building your own toilet?
  5. My Conclusion
  6. Further links

How they are structured, what you can expect for your money, and which advantages and disadvantages they have.

With one of these “separators” each of you should be able to build your own separation toilet. All that’s missing is the bucket and the urine container.

1. What is the Urine Separator Insert for?

The composting toilet consists of three essential components. Firstly, we have the actual separation insert, which separates the liquid from the solid, as well as the containers for the urine and for the solid.

The separation insert is the heart of every composting toilet. Using this insert the urine should be separated cleanly from the solids.

By separating you ensure that the excretions do not mix.

The advantage: the separated excrement does not stink and your toilet is therefore odorless.

Why it is like that? Basically, the urine does not smell as long as it does not decompose. 

The solid also does not smell when it has dried thoroughly. Most use a suitable sawdust or dry litter (e.g. small animal litter) for this. 

Depending on the degree of use, you should also provide the separation toilet with a fan. This ensures that excess moisture is removed from your toilet and thus supports faster drying.

The better the separation works, the less effort you will have later with your separation toilet.

Please also have a look at the following blog article on the structure and function of a separation toilet.

2. Which Urine Separator Inserts for Dry Toilets are available?

Quite a large selection of Urine Separator Inserts for composting toilets now exist. Depending on where you use your dry toilet, e.g. in a mobile home or as a garden toilet or in a holiday house, one or other of the composting toilet insert has its advantages.

The most popular Urine Separator Inserts for composting toilets, separation toilets and dry toilets on the market are currently:

  • Separett Privy 501 (500 and 400)
  • New: Trobolo Urine Separator
  • Kildwick with classic and XL
  • Free range design from Great Britain
  • Tractor funnel from the hardware store

In the following subchapter I go into more detail about the individual separation inserts.

3. Advantages and disadvantages of the individual Urine Separator for dry toilets

Urine separator insert

Separett Privy 501 (500, 400)

It is from Separett and is available in different versions:

  • As Privy 501 (see picture above), as well as in variants
  • Privy 500 (with a hard foam toilet seat)
  • Privy 400 (without anything additional – the separation insert only)
  • Privy 503 (with a wooden seat)

All are available in Separett blue and, more recently, in gray.

This separation insert comes from Sweden. That is, from the country where the composting toilet/ dry toilet is very common and popular.

Separett therefore has a great deal experience with separation and composting toilets. In addition to separation inserts, Separett also builds completely finished separation toilets / dry separation toilets.

In addition to the actual separating insert, the Separett Privy 501 also comes with a toilet seat in white.

All for a price of 117 EUR. (Here in store)

The delivery also includes a 2.5 m spiral hose to drain the urine into a suitable canister.

The Separett Privy 501 Urine Separator

Is quickly installed in a previously sawn hole using four screws. A template is also printed on the box.

Even if you have not sawed accurately, you will not notice it later, because the separating insert has a large edge and is inserted from above.

Manufactured using the injection molding process, it has a high manufacturing quality, with a very smooth surface which makes cleaning very easy. Dirt is of course not as noticeable with grey separation insert as with the white one.

The insert also includes a small additional plastic part, which you can choose to click into the rear area of ​​the separating insert.

With this insert, the urine area is enlarged by approx. 1 cm and extended to the rear. Depending on the seating position, this can be an advantage.

In addition, the rear edge increases by approximately 1.5 cm. This provides improved protection against urine flow into the solids container.

When in use, you should regularly remove this component and clean it accordingly.

Apart from this, the additional part here forms a very nice, high edge that safely drains the urine to the front. 

But as I said, you do not have to use the insert element. Just try it out.

So far, unfortunately, this was only available in blue, which stopped some from using this separation insert or switching to the Privy 500/400 in grey.

But now it is finally also available in grey, see photo. This will also make your separation toilet more aesthetically pleasing.

This separation insert is not the cheapest, but you get a matching toilet seat and a 2.5 m spiral hose included.

In the shop you can get the Separett Priy 501 separation insert for 117 EUR. 

Alternatively, there is also a partition insert with a hard foam toilet seat as the Privy 500 for 85 EUR.

Or without a toilet seat as the Privy 400 for 82.50 EUR.

You can find all versions under separation inserts here in store.

TROBOLO Urine Separator

Besides Separett and Kildwick, Trobolo is also known as a manufacturer of composting toilets.

Up to now, however, one could not buy the composting toilet inserts separately. This has now changed. Therefore I also introduce this urine separator insert to you.

I think that the Trobolo is a good alternative to the above mentioned ones.

Urine Separator Trobolo

Like the former Kildwick, when it came from England, this Urine Separator is made of GFRP.

It is very stable and of high quality. From the top it has a very smooth surface, from the bottom it is a bit rougher. This is due to the GFRP fibres, which can still be seen here.

Trobolo has painted over this, however, so that the lower part of the separator can be cleaned easily. 

The layout is similar to the Privy of Separett. The only difference is that no wedge was used here to expand the urine bowl.

The outer dimensions correspond more to the Kildwick Klassik divider. So that the Trobolo urine separator appears here also very compact.

Depending on which toilet seat you decide on later, the Trobolo separating insert disappears very well under the toilet seat.

It is very stable and can be installed really well.

The insert is available in dark gray and white. Especially with the white version, your future toilet will look very similar to a normal household toilet.

You will find further information here.
I personally think that the Trobolo urine separator is a very good and inexpensive alternative to the Kildwick Classic.

The Urine Separator Insert from TROBOLO you can buy for EUR 99.90 here in the shop!

Kildwick Classic and Kildwick XL

New, and yet not new.

These separation toilet inserts are the latest on the market. However as the name suggests, Kildwick is not really new.

A German company has taken over the Kildwick firm and is now producing the popular plastic separation toilet inserts again.

The separation inserts are deep-drawn from polystyrene. They have a wall thickness of approx. 5 millimeters and are therefore very stable.

Tests have also shown that they can survive a fall from 6 metres unscathed.

Due to the manufacturing process, the surface is very smooth – from above and from below – and is easy to clean.

Since the separation inserts are based on the old Kildwick experience, the separation area is optimally designed. So it is also very good for women to use.

Kildwick Germany has adopted the tried and tested, and implemented it in a modern way.

The new inserts for separation toilets are currently available in two versions and two colors (white and black). See the picture above.

The Kildwick classic version

Corresponds to the earlier Kildwick separating inserts made of GRP (glass reinforced plastic).

They are available in white and black.

The edge of the new XL version was deliberately kept very large so that you can cut it down accordingly. 

This has the advantage that you can use it to create a homogeneous surface without edges on your toilet. 

I can also show you the example of the carpenter’s composting toilet.

This is also available in white and black.

Thus, Kildwick currently offers a good selection of separation inserts for the construction of your separation toilet, compost toilet or dry toilet.

All versions of the separating insert (classic and XL) are currently available for EUR 129.

Long-term experience with these separating inserts does not yet exist, but Kildwick has taken a lot into account in order to be able to deliver good separation inserts in the future.

I also created a video for this. To the video.

Freerange design separating insert

The Freerange design separator insert also comes from the UK.

The company currently only offers the funnel; apart from this it produces nothing in the area of ​​dry or separating toilets.

The insert is available in white (as here in my photo) or in black.

Both can be obtained here on Amazon for 40 EUR.

A small installation instruction in English comes with the delivery.

The ideal mounting point is also described here.

The funnel is the front urine collector

A small sieve is supplied with the insert. Probably for collecting kidney stones. 

Unfortunately, you can’t really fix the strainer in place unless you use super glue.

In my opinion, the funnel could be a little bigger so that the whole thing is more suitable for women. 

The shape also creates a drip edge where something can quickly flow down into the toilet without being noticed.

This is a simple deep-drawn part. As can be seen, it is moulded from a square piece of plastic. Depending on the use, the edges should still be trimmed.

The surface is a bit bumpy due to the manufacturing process. The funnel is also not quite as stable as that of Separett and Kildwick, but also not as expensive.

You have a relatively open hand with the installation, as I said, the edge may need to be trimmed a bit. You can also use it with a standard toilet seat.

The Urine Separator Insert from Freerange Design is available here on Amazon.

Tractor funnel as a separating insert

If you really want to save, I would like to introduce you to this alternative…

I once found this idea in a forum and for the sake of thoroughness I don’t want to leave it out

A tractor funnel for pouring oil.

Yes, you understood correctly. It is a funnel from the agricultural sector.

The funnel has more or less similar dimensions to the Urine Separator from Freerange Design. It also has the strainer.

The funnel is also available in white and black from Amazon. It is also a plastic deep-drawn part.

alternative urine separator

The catchment area is relatively narrow

and therefore not really suitable for women. I also find the look not really appealing. But if you are looking for something really cheap, you can adapt it for your purposes.

But be careful, there are a few things to consider:

The funnel has a very small rim, which makes installation a little difficult. There is not much space left for the screws.

It is also goes down to a considerable depth. For this reason an appropriately flat bottle or canister must be found, or else the toilet itself must be designed accordingly high.

But if you just install a hose for discharge, you will certainly get along all right.

By the way, the funnel is available here at Amazon for 12.70 EUR.

4. The basics to consider when installing

Women and men are anatomically different. This is especially true when using a composting toilet.

You should pay attention here to the optimal positioning of the Urine Separator Insert. The best thing to do is take a test wee beforehand.

It is also important that we males do not use the toilet while standing, because it is guaranteed to go “wrong”. But this should be obvious.

The more upright you are on the toilet, the better you can aim. So just practice a little.

Incidentally, this also applies to the ready-made toilets available for purchase.

I will post my own article on this later. If you don’t want to miss it, just sign up for the separation letter at the bottom, below the blog post. I will let you know whenever there is new information.

Or just drop in again on occasion at
Here you can find my shop with a large selection of different products, self construction sets and accessories.

My conclusion

There is currently a good variety of separation inserts for building your own eco toilet, dry toilet and composting toilet. Regardless of whether you want it for your summer house, boat, holiday house or mobile home.

Depending on your preference and budget, there is something for everyone.

For me, the Urine Inserts from Separett and TROBOLO are the best choices. They are stable, well thought out and are good quality products.

The Separett captivates with its toilet seat combination, is inexpensive and also quite respectable in the new gray color. Combined with the toilet seat, this insert is somewhat larger. So be sure to note the dimensions if you have limited space.

The new TROBOLO is based on a proven shape, looks good, is very compact and works well for women and children too. The separation toilet inserts are available in white, which is great. TROBOLO is very compact and therefore my first choice when space is tight.

The other Urine Separators also have their own benefits. As so often, it depends on your own preferences.

Separett PrivyMaterial: Polypropylene by injection moulding
different variants available:
501 with toilet seat – 115,- €
503 with wooden seat + lid – 127,-€
500 with hard foam seat – 85,- €
400 only urine separator – 82,50 €
including spiral hose & sawing template on the box
quick and easy installation (4 screws)
very smooth surface
Kildwick TrenneinsatzMaterial: deep-drawn polystyrene
two variants are available:
Classic – 129,- €
XL with very large rim – 149,- € at Amazon
very smooth surface
very stable (wall thickness 5 mm)
do not clean with acidic cleaners such as diluted vinegar/ lemon (surface is attacked)
good proportions of the separating insert
Trobolo TrenneinsatzMaterial: GFRP
very stable and high quality
very smooth on top/ slightly rougher on the bottom
compact design and well suited for small eco toilets
simple installation
different colours for 99,90€
Freerange Designvery inexpensive variant (40,- € at Amazon)
consists only of the urine funnel
from GB with english building instruction
somewhat short – could be problematic for women
Surface somewhat wavy and not as stable as Separett or Trobolo
Tractor funnelvery inexpensive version (12,70 € at Amazon)
is a misappropriated use
not well suited for women, because very narrow
assembly a little difficult – very small rim for screws
due to its deep construction it needs a very flat urine bowl or a high toilet bowl
alternatively urine can be drained with a hose

What kind of Urine Separator Insert are you using? What is important to you? Do you have any questions that remain unanswered here?

Write to me in the comment section. I’m looking forward to it.

Yours, Markus

If you are interested in a complete composting toilet, then read my contribution here.

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