Probably the nearest to your home loo experience, a flushable camping toilet can be permanently fixed (emptying from the outside of your van) or portable (emptying from a removable cassette).

Flushable camp loos have two sections, which help keep your van free of toilet smells. You fill the top section (the toilet bowl) with fresh water (and some chemicals that smell nice), do your business, then flush the mixture into the lower waste tank. The business and its smells are sealed into the waste tank until you take it to be emptied (this is the part I’m really not keen on).

There are bio-friendly additives available for this type of toilet but you do need to find an emptying point when the bottom tank is full.

Composting toilets use natural processes to break down poo into compostable material. This only works properly and in a smell-free way if you separate the wee from the poo, then cover the poo with a biodegradable material.

Quality composting camp toilets have a separator, which (when used sitting down) diverts the wee into a container. You then need to lightly cover the poo with material (usually sawdust).

In theory, you can carry several weeks worth of composting poo with you and empty the wee out when you find a suitable location. Most good composting toilets don’t smell. Composting toilets that don’t separate wee and poo are more likely to smell because of the reaction between the two.

Self-sealing toilets collect wee and poo into a plastic bag then seal the bag shut. Set up involves correctly inserting a bespoke tube of plastic and make sure this is sealed at the bottom before you start.

Because wee is liquid, most self-sealing toilet systems include sachets, which convert it to a gel-like substance. The bag is sealed top and bottom and can be stored for you to dispose of how you wish. What the best options for this are, I am not sure but composting bags are available for some systems.

These systems could be very wasteful of plastic if you used them every time you wee but there are options available that incorporate a diverter, which directs the wee into a separate container and the poo into the bag sealer.

Flushable camp toilets are generally considered to be less sustainable than composting toilets. This is because of the chemicals in the flush system used to deodorise and break down poo and paper.

These synthetic chemicals are toxic to nature and can’t be emptied wild or flushed down normal drains.

There are some highly rated ‘green’ flush liquid alternatives, that are less damaging to nature but emptying into a designated system is still the only sustainable option. Some campsites only accept ‘green’ flush toilets.

A separating compost toilet system can be a sustainable option, especially if you have space and opportunity to compost the solid waste yourself once you get home.

Compost toilets that do not separate don’t offer such a sustainable solution because they are more smelly and require you to use a public bin to dispose of your waste.

When choosing a composting toilet system, you might want to look carefully at the sustainability of the sawdust or other bio medium offered.

The obvious sustainability problem with self-sealing camp toilets is their use of plastic but if you’re using them for all your wees, you’re also going to get through a fair few sachets of gel-forming substance.

We wee more than we poo so saving the self-sealing bag system for the latter would save plastic. This would rely on you finding another toilet option when you needed to wee.

Compostable bags are available with some versions of the self-sealing toilet but I suspect these would be less sturdy.

Although the flushable toilet is a tempting option, I have a couple of issues with it. The flush chemicals would bother me and I’m a tad squeamish about the idea of carrying and emptying my waste at a campsite.

I think a composting toilet with a separating system would be my preferred option. I have a sensitive nose but I know from experience that composting toilets smell mostly of woodchip. I also like the idea of no chemicals and home composting.

I’d be interested to try a self-sealing camp toilet, especially from the point of view of smell but I think I’d be concerned about the faff and environmental issues of the plastic bags as well as limited acceptable disposal options.