Zero Discharge

Non-composting, waterless toilets for busy sites.

On very busy sites composting becomes tricky and urine separation may not be so reliable. The problem can be the sheer volume of solid wastes and, where urine is concerned, the public may not follow simple instructions to ensure that urine separation works well. There are also sites where discharge of urine to ground is not be permitted. This is often the case on Sites of Special Scientific Interest (SSSIs).

Our Zero Discharge toilets arose from a request by The Royal Parks to develop a design for the Isabella Plantation (a SSSI) in Richmond Park, London where use is also heavy. You can read the case study here.

Hetland Garden Centre pedestal. Waterless toliet in situ.

Solids and liquids enter a storage tank and emptying is by slurry tanker from outside the building. Due to it being a waterless toilet, the lack of any flush water means emptying is infrequent.

No 'soak' material is added to this waterless toilet and maintenance requirements are very low.

Ventilation is achieved by the use of a passive duct and extraction cowl or by low power fan depending on the site. This results in a completely odour free cubicle under normal operating conditions.

The Zero Discharge toilet (ZD) now comes in two models: Types 1 & 2.

Type 1 Zero Discharge


Zero Discharge, waterless toilet, Schematic


  • Below floor 3m3 storage tank
  • Stainless steel pedestal with Teflon coating to inner surface
  • Extraction cowl or fan unit and power supply as required
  • External airtight emptying hatch
  • Cubicle connection point for urinals and waste water from basins

Optional extras

  • Gel dispensers
  • Ceramic water-less urinal
  • Grab rails
  • Vent pipes

The Type 1 is typically installed in large facilities with a number of cubicles side by side. The building is likely to be architect designed. We would normally be involved as part of a design team to advise on how to relate the building to the tanks and ventilation system.

Emptying of the tanks takes place at the rear of the building through an emptying hatch.

Type 2 'stand alone' Zero Discharge

The interior of a NatSol Zero Discharge toilet for remote sitesThe Zero Discharge Type 2 (ZD2) is a stand alone waterless toilet rather than one designed to fit into a larger architect designed facility.

It creates a fully accessible cubicle and can be supplied with the same range of NatSol buildings as the Full Access Composter (FAC) – or you can build your own. From the outside the toilet might therefore look almost identical to the FAC except that we supply a taller vent pipe for the ZD2.

There is no urine separation and therefore no urine soak-away. The pedestal has a different shape and is topped with a Corian seat. The inside surfaces are Teflon coated.

Emptying of the toilet is carried out by slurry tanker and access into the tank below the floor is by removal of the pedestal.

We supply a male urinal, a gel dispenser and grab rails.


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