GeoTrap Nutrient Filter for Dry Toilets

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£200.00 excl. VAT

Free next day UK delivery

GeoTrap Nutrient Filter box purifies the leachate or seep liquid from the WooWoo GT or similar composting toilets by running it through a natural mineral sand. Nitrates and phosphates are absorbed into the mineral to keep them out of the environment – perfect for areas where there is a nitrate or phosphate neutrality requirement or recommendation. Cannot be used in conjunction with neat urine.

Available on back-order


The GeoTrap nutrient filter box is designed to purify the leachate or seep liquid that comes out of the WooWoo GT range of composting toilets. Inside the GeoTrap Nutrient Filter box is the GeoTrap Nutrient Trap mineral which absorbs the majority of the nutrients (eg. phosphorous and nitrogen) from the leachate liquid. The resulting purified liquid can be led directly to the ground.

The GeoTrap filter box is the perfect addition to a batch or split composting toilet, where you want to filter the output and reduce the nitrates and phosphates.

Please note that the GeoTrap filter is unsuitable for urine-diverting toilets – it cannot be used for pure urine.

The GeoTrap contains a combination of natural minerals and has been developed by Åbo Akademi University in Finland. The mineral sand absorbs and locks in nitrogen and phosphorous. For most users, the mineral sand should be replaced once a year – the used mineral can be composted or applied directly to ornamental plants as a fertiliser, where the nutrients become bio-available.

The GeoTrap filter works in all temperatures as the filtration is not dependent on bacterial activity.

Installing the GeoTrap

The GeoTrap Nutrient Filter box should be set into the ground, behind your composting toilet, so that the liquid inlet connector is in line or slightly lower than the outlet on your composting toilet base. Use the flexible pipe that comes with your toilet to connect to the inlet side of the GeoTrap, trimming the pipe as required.

GeoTrap nutrient filter installed with a WooWoo GT dry toilet

Connect the supplied outflow hose to the outlet on the GeoTrap and lead this pipe to the ground, ideally around large plants or trees. Do not lead the outlet directly into a water source.


  • GeoTrap Dry Toilet Filter with lid
  • Outflow hose, Ø 32 mm, length 1,5 m
  • GeoTrap filtering mass, 5 kg bag


  • Height: 30 cm
  • Length: 35 cm
  • Width: 35 cm
  • Incoming hose at 16 cm from bottom, outcoming hose at 14 cm from bottom
  • Volume: 25 L
  • Weight (empty): 2.5 kg
  • Material: PE


The Geo Trap filter mass, being a natural product, is difficult to deliver precise cleaning measurements on. In addition, the concentrations of the various elements in the incoming leachate will differ greatly between users. However, ‘real world’ analysis shows that Geo Trap – correctly maintained, and when dealing with leachate from a WooWoo GT composting toilet, will give a cleaning efficiency of around 77% for phosphorus and 73% for nitrogen.

Additional information

Weight 1 kg
Dimensions 40 × 30 × 20 cm


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