Buller residents to benefit from local green waste being repurposed

Buller residents will be able to dispose of their garden green waste for free at the Westport and Reefton Transfer Stations for a seven-month period beginning 2 December 2024.

During this time, a composting trial, mixing wastewater sludge with garden waste will take place at the Westport Wastewater Treatment Plant.

Wastewater sludge consists of the solid organic, mud-like material that is left behind after wastewater has been treated at the wastewater plant. Composting makes it possible to turn the sludge into a compost like material that has a variety of uses such as a soil conditioner for landscaping.

Until recently, the sludge was mixed with sawdust and used for soil improvement at a site near Greymouth. This facility has now closed, requiring council to find an alternative end-use.

As with home composting, large-scale industrial composting requires mixing different materials to create the right environment for decomposing.  Using green waste provides the required nitrogen to kick start the process, and adds additional bulk, enabling the sludge to break down over time.  

The composted material will be tested and the results will determine what it can be used for.

Group Manager Infrastructure Services Anthony Blom says: “It is great to see how our wastewater and solid waste teams are working together to find a solution that benefits our community, keeps the processing local and turns garden green waste and sludge into a useful product.”

Customers can bring in anything that grows in their garden – apart from flax, cabbage tree leaves, and wood/logs over 300mm in diameter. These will contaminate the compost and damage the shredding machinery. Those non-compostable items have to be disposed of as normal rubbish in a separate load. People also have to be careful to keep their garden green waste free of rocks, plastics or other items since these will damage the mulcher.

Mr Blom emphasises, “It’s important to make sure the green waste meets these standards, as items that are not allowed, such as flax or rocks, may cause damage to the industrial mulching machine and pose hazards to people operating the machinery.

We encourage customers to support our staff by dropping off only ‘clean’ green waste. This will help the trial succeed, and a successful trial should result in both a positive environmental outcome and ongoing free garden green waste drop off.”

People living in Karamea, Inangahua, Maruia and Springs Junction can also transport their green waste to the Westport or Reefton Transfer Stations for free disposal.

-ENDS-

For further information please contact:
Community Engagement Team  
Buller District Council
Media.Enquiries@bdc.govt.nz