On-site grease-trap waste management
WCTNZ® Grease Compost Box
A ready-to-use, pre-dosed composting service pack for controlled on-site management of kitchen grease-trap service waste.
Each Grease Compost Box is supplied assembled with a fitted 35L compostable liner and a measured charge of proprietary WCTNZ® Grease Compost Media. Larger grease-trap service loads simply use additional boxes.
FormatReady to Use
Supplied assembled
MediaPre-Dosed
WCTNZ® proprietary blend
MethodFill • Close • Mix
Simple service process
Larger ServicesAdd Boxes
Match the actual service load
Product background
A simple way to manage grease-trap service waste
Grease traps protect downstream wastewater systems by capturing fats, oils, grease and food-related material that must eventually be removed during servicing.
At suitable off-grid and privately managed wastewater sites, the WCTNZ® Grease Compost Box provides a controlled way to prepare that material for transfer into the site’s main composting system.
One standard Grease Compost Box is used throughout the system. Where a servicing job produces more residue than one box can accept, the material is simply divided between additional boxes.
Using one standard box keeps the pre-dosed media, operating method and handling process consistent while allowing the number of boxes to scale with the actual service load.
What is supplied
A complete pre-dosed service pack
Product format
Ready-to-use WCTNZ® Grease Compost Box supplied assembled.
Box dimensions
Approximately 310mm long × 225mm wide × 250mm high.
Internal liner
Fitted 35L compostable liner supplied as part of the service pack.
Grease Compost Media
Pre-measured proprietary WCTNZ® Grease Compost Media supplied inside each box.
Media starting volume
The loose pre-dosed media occupies approximately one-third of the box before grease-trap service residue is added.
Larger service loads
Additional identical Grease Compost Boxes are used as required rather than overfilling one box.
WCTNZ® Grease Compost Media
Proprietary media prepared for grease-trap residues
Each Grease Compost Box contains a measured charge of proprietary WCTNZ® Grease Compost Media formulated for receiving kitchen grease-trap service residues.
The light, structured media provides an absorbent matrix through which grease, moisture and food-related material can be distributed during mixing.
As service residue is mixed through the loose media, grease and moisture can move into the available structure of the media rather than remaining as a concentrated wet layer.
WCTNZ® Grease Compost Media is supplied ready for use as a proprietary formulation. The customer does not need to measure, blend or formulate additional treatment media.
How it works
Open, fill, close, mix and compost
- Take the assembled Grease Compost Box to the grease-trap servicing area.
- Open the box and liner ready to receive the removed service residue.
- Add the concentrated grease, food solids and sludge removed during servicing.
- Do not exceed the marked MAX MIX working level.
- Close the compostable liner and box as instructed.
- Shake, roll or carefully turn the closed box to distribute the service residue through the WCTNZ® Grease Compost Media.
- Transfer the complete box into the suitable receiving composting system.
If the service residue exceeds the working capacity of one box, divide it between additional Grease Compost Boxes rather than overfilling a single box.
Service guide
Typical box quantities for different grease-trap sizes
Smaller grease trap
Typically 1 Grease Compost Box for a normal service load. Passway™ M-43F is the current reference size.
Medium grease trap
Typically 2 Grease Compost Boxes for a normal service load. Passway™ M-43E is the current reference size.
Larger grease trap
Typically 3 Grease Compost Boxes for a normal service load. Passway™ M-43D is the current reference size.
These quantities are practical servicing guides rather than maximum-capacity guarantees. The actual number of boxes required depends on the amount and consistency of the concentrated grease, food solids and sludge removed at the service event. Use additional boxes whenever the service residue would exceed the MAX MIX level.
What goes into the box
Concentrated kitchen grease-trap service residue
The Grease Compost Box is intended primarily for the concentrated material removed during routine grease-trap servicing, including:
- Separated fats, oils and grease.
- Food-related solids retained by the grease trap.
- Grease-rich sludge removed during servicing.
- The residual moisture carried with the removed material.
The complete liquid contents of the grease trap do not normally need to be transferred into the Grease Compost Box. Relatively clear underlying wastewater should be managed through the site's appropriate wastewater arrangement rather than unnecessarily filling the compost box with water.
Best suited for
Off-grid and privately managed wastewater sites
- Off-grid homes and cabins.
- Private on-site greywater systems.
- Remote properties managing organic waste on site.
- Sites using a suitable established composting system.
- Grease-trap installations where routine service waste needs a practical on-site management method.
What stays out
Keep incompatible waste separate
- Toilet or blackwater waste.
- Petrol, diesel, engine oil or other petroleum hydrocarbons.
- Solvents, paint, pesticides or hazardous chemicals.
- Unknown or chemically contaminated waste.
- Plastic rubbish and other non-compostable foreign material.
Receiving compost system
The box prepares the residue for continued composting
The Grease Compost Box is a service and transfer pack rather than the complete composting process.
After the grease-trap residue has been mixed through the WCTNZ® Grease Compost Media, the complete box is placed into a suitable larger composting system where continued biological breakdown and maturation can take place.
Recently added grease-trap material must not be treated as finished compost. Allow the receiving composting system adequate processing and maturation time before final use.
Site suitability
Designed for controlled on-site use
The WCTNZ® Grease Compost Box is intended for suitable off-grid and privately managed wastewater sites where organic material is already managed through an appropriate composting system.
Commercial grease-trap and trade-waste obligations can be different and may require captured grease and sludge to be removed through an approved waste service.
Commercial premises should not substitute the Grease Compost Box for a required grease-trap waste-collection or trade-waste arrangement unless the relevant authority or wastewater operator accepts the proposed method.
WCTNZ® support
A scalable part of on-site grease management
WCTNZ® can help determine the number of Grease Compost Boxes appropriate for the grease trap, servicing frequency and wider on-site wastewater arrangement.
Additional service capacity is provided simply by using additional complete Grease Compost Box service packs.
