The report has combined class 1 & 2 landfill figures with farm dumps to arrive at 1,800,965 tonnes of available waste in the South Island. The report states, SIRRL “has secured access to approximately 365,000 tonnes, which equates to just 20% of the total available quantity of waste.”

The report also states that SIRRL has signed conditional heads of agreement with waste suppliers to provide the plant with the yearly waste volumes.

But do these figures add up?

FARM dumps

The report fails to provide any method for acquiring waste from farm dumps. This would need to involve collecting each individual farm from the entire South Island and transporting the waste to Glenavy for incineration. 

Clearly, this is not viable, so let’s subtract the 344,866 from the 1,800,965, which brings us back to 1,456,099 tonnes of waste available.

Class 1 landfills and class 2 landfills

The OTO report provides an approximate waste composition (table 4, page 17), sourced from Solid Waste Analysis Protocol (SWAP) data produced by the Christchurch City Council in 2019.

The table provides figures for recyclable and compostable content from class 1 and class 2 landfills as follows:

• Recyclable paper and cardboard         15.88%
• Recyclable plastics:                                  5.30%
• Compostable green waste:                    15.64%
• E-waste                                                       0.88%
• Kitchen food waste:                                  0.03%

TOTAL:                                                             37.73% = 549,386 tonnes

Non-combustibles.

The table also provides a list of non-combustible materials that provide no calorific value when put through the incinerator, including;

• Glass                                                       2.23%
• Concrete, ceramics and rubble           3.77%
• Metals                                                     2.00%

TOTAL:                                                         8.00% = 116,487 tonnes

If recyclable and compostable material were correctly sorted and recycled using currently available recycling practices, waste would not contain recyclable and compostable material. Using the data provided by SIRRL, that’s 37.73% of the available class 1 & 2 landfill material.

As mentioned, glass, concrete, ceramics, rubble, and metals hold no calorific value and, therefore, will not provide any energy recovery benefit when processed through an incinerator; it will actually end up as part of the resulting bottom ash, which the company claims it will landfill until better options become available, if at all.

This 8% non-combustible material equates to a further 116,487 tonnes. 

If we take the combined class 1 & 2 landfill material and subtract the recyclable, compostable, and non-combustible material, we get 790,226 tonnes.

South Island class 1 & 2 landfills                                            1,456,099

recyclable/compostable content:                                               549,386

non-combustible content:                                                            116,487

TOTAL:                                                                                            790,226 tonnes

So, while SIRRL claims that the proposed Waimate incinerator will require only 20% of the South Island’s 1,800,965 tonnes of available waste stream, that overall figure includes recyclables, compostable material, non-combustibles, and waste disposed of in private farm dumps. If this material is removed from the waste stream, Project Kea’s required 365,000 tonnes per year amounts to approximately 46% of the available class 1 & 2 landfill content, not 20%.

Potential for further recycling.

The OTO report, table 4, also provides a list of waste, including other potentially recyclable materials, including; 

• Soft plastics:                                                    6.83%
• Clothing and textiles:                                      7.73%
• Timber                                                             15.95%

TOTAL                                                                   30.51%

If this potentially recyclable material were to be removed from the future waste stream, it would deplete the waste quantities even further, perhaps by as much as 30%, or 237,068 tonnes.