Inside the Material Recovery Facility (MRF)

Ever wondered what happens at a transfer station? At the WM Material Recovery Facility (MRF), materials are sorted, processed, and prepared for recycling. Every day, 103 metric tonnes of material pass through the facility, and thanks to meticulous sorting, only around 3 metric tonnes end up in landfill due to contamination.

Key Takeaways from the MRF:

• Hand Sorting Matters: Paper, plastic, and polystyrene are sorted manually!
• Not Everything is Recyclable: Commercial cardboard tubes, for example, contain so much glue that they can’t be recycled. But, your household ones CAN go in the yellow bin! 
• Eyes on the Process: Low contamination rates are achieved because materials are checked at every stage of the process. 
• Cardboard Recycling: All cardboard is shipped overseas since New Zealand currently lacks the infrastructure to process it.

“Even if it is cost-neutral, I still think it is worth it because it keeps that material out of landfill.” – Steven (WM MRF Manager)

The Story of Kate Valley Landfill

Established in 1995 by Gareth James, Kate Valley Landfill was the first regional, multi-council partnership landfill in New Zealand. It is 50% publicly owned (by councils) and 50% privately owned (by WM).

Prior to its establishment, there were 52 smaller dumps across the region, which were unable to meet modern environmental standards. Kate Valley was designed to provide a long-term, resilient waste management solution.

Why Kate Valley Stands Out:

• Long-Term Planning: Although it operates under a 35-year consent, planning extends over 100+ years, ensuring future resilience.
• Environmental Monitoring: Continuous checks on waterways and gas emissions help minimize environmental impact.
• Strategic Land Use: Only a small portion of the purchased land is used for waste disposal; the rest provides silt and aggregate for landfill construction.
• Community Considerations: The nearest neighbours are over 2km away, reducing impact and gaining community support.
• Global Best Practices: Operations are peer-reviewed by international experts to stay ahead of environmental regulations and innovations.

Anatomy of Kate Valley Landfill

The landfill isn’t just about disposal; it’s about controlling and minimizing environmental risks.

How the Landfill is Engineered for Safety:

1. Preventing Leachate Contamination:
   • Water that touches waste (leachate) collects heavy metals and other harmful substances.
   • The landfill sits on natural mudstone, an impermeable layer with no faults or aquifers.
   • Drains capture leachate, which is evaporated, and the remaining concentrate is reintroduced into the landfill so it is locked away. 
2. Multi-Layer Protection System:
   • 1 metre of compacted silt (sourced onsite) provides an impermeable barrier.
   • Three-layer liner system: HDPE plastic sheets sandwich a layer of synthetic clay that self-seals if punctured.
   • A 0.5-metre protective layer of aggregate further shields the liners.
   • The first 3 metres of waste is uncompacted to prevent liner damage (the “fluff layer”).
3. Strict Waste Disposal Controls:
   • Only a 30×30 metre section (the “open face”) is active at any given time.
   • Each night, the open face is covered to prevent waste from escaping.
   • Work is paused if wind conditions risk blowing rubbish away.
   • Any escaped waste is collected and removed immediately.
4. Turning Waste into Energy:
   • Gas wells capture landfill gases, converting them into electricity.
   • Currently, Kate Valley generates enough power for 2,100 homes— and is currently limited only by the capacity of local power lines.

Photo from Transwaste website of the liner system being laid down. 

The Bigger Picture

“If we have to have waste, let’s have it in one, well-controlled area.” – Hamish Riach

• Kate Valley processes 350,000 tonnes of waste per year, averaging 700-800 kg per person annually.
• Climate Resilience: Built-in resilience measures ensure Kate Valley is prepared for long-term environmental challenges.
• Carbon Sequestration: The surrounding land also contains 400 hectares of pine forest.

The Waste Levy and Its Impact

Introduced by the Ministry for the Environment, the Waste Levy discourages landfill use and encourages recycling.

• Currently set at $60 per tonne, the levy is scheduled to increase, making landfill disposal less financially viable.
• Effect on Industry: One notable change due to the levy is the decrease in GIB board waste sent to landfill as companies find alternative recycling methods.

Looking Forward

The future of waste management in New Zealand is evolving, with increasing focus on reducing waste at the source and finding sustainable alternatives. Whether through better recycling, landfill innovation, or reducing single-use items, every small action contributes to a cleaner, more sustainable Aotearoa.

One of the most inspiring things from the day was hearing people in the waste industry say that the plan is to have no rubbish! It feels like reducing waste is now mainstream and we are all on the same page. Kate Valley is so future-proofed that even if landfill reduces, they have ways to pivot toward other incomes. Amazing! 

Thanks to WM!

This blog is a summary of our tour of WM and Kate Valley that was generously organised by Sarah Hendry, WM. This tour provided an opportunity for a few of our members and member organisations to learn about our local waste systems. 

If you are interested in being a part of the next tour get in touch with Anthea (anthea@remixplasitc.com) and we will add your name to the list!

Attendees included: 

Nicola from Upcycled_Plastic

Jess from Without Waste NZ

Nikki of NikkiWB Ceramics and E5artandclay 

Anthea from SŌC and Remix Plastic

Alan from Ecotech Services Ltd

Cath from Riverlution  

Kat from SŌC and 

Thomas, SŌC member

Sara, SŌC member

Sarah from WM