Waste minimisation and management
Waste includes materials, from any source, which are unwanted, unvalued, and are to be discarded or discharged. Wastes can be solid, liquid or gaseous, or a combination of these. The amount of waste being created in Canterbury/Waitaha continues to increase.
Key drivers for this are increases in population and economic growth, combined with a lack of available alternatives and poor practices around waste minimisation. Disposing of waste sustainably can be costly and requires land and resources that otherwise would be available for other purposes. Waste also produces greenhouse gases and emissions of ozone that contribute to climate change.
Here are the current issues faced around waste minimisation and management in Waitaha.
Issue: Waste creation and management come at a cost to people and the environment
When items become waste, they contribute to unsustainable practices such as the need for more natural resources for replacement items as well as the many implications of managing the waste itself.
Waste management requires infrastructure for collection and storage, transfer and processing facilities with suitable transport connections.
This infrastructure and its operation has environmental effects. For example, solid wastes are commonly transported by road leading to increased emissions, and processing requires inputs of energy and water.
Some waste materials, such as organic and refrigerant wastes, can lead to greenhouse gas and ozone emissions and have impacts on climate change.
Waste management may also cause nuisance problems such as litter and odour or localised pollution and can lead to the contamination of land, water, and air.
Waste management hierarchy
Minimising the amount of waste that is created can reduce these impacts and is achieved where wastes are managed higher up the waste management hierarchy.
The waste management hierarchy first seeks to avoid the generation of waste, and where this cannot take place the amount of waste that is produced should be reduced. Thirdly, items should be reused.
Where reuse is not an option, items should be recycled, and where items are not able to be recycled, resources may be recovered.
When all useable resources have been recovered, the item may enter the waste stream as residual waste.
Waste management hierarchy - Image source: Ministry for the Environment/ Manatū Mō Te Taiao
Waste minimisation initiatives
Initiatives to promote waste minimisation are being undertaken by central government at a national level as well as by councils at the regional and local level.
For example, at the national level the product stewardship scheme provides a consistent approach for the recovery and reuse of products such as tyres, electrical and electronic products (e-waste), refrigerants and other synthetic greenhouse gases, agrichemicals and their containers, and farm plastics and packaging.
At the regional level, the Canterbury Waste Joint Committee provides strategic leadership to the waste management sector. At the local level, local councils prepare waste minimisation and management plans in their role as municipal waste collection and disposal authorities.
Different waste types created in Waitaha
The six main waste source categories are:
- domestic kerbside waste
- residential waste (residents taking waste direct to landfill)
- commercial or industrial
- construction or demolition
- landscape (green) waste
- special (hazardous) waste.
Specific types of waste produced include electronic waste, metals, glass, timber, rubble, tyres, plastics, and hazardous waste. Methods of management are dependent on the waste type and include options such as transfer stations, processing facilities, or material recovery facilities.
Wherever possible, usable materials can be recovered, such as landscaping supplies and garden mulch, or recycled in New Zealand/Aotearoa or overseas. Where recovery or recycling isn’t possible, waste will end up in landfill.
Challenges and opportunities
Current waste issues in Waitaha include the way we manage old tyres, coal tar and treated timber.
A further challenge is the need for better information on the quantity, location and management of different wastes. It is estimated we presently hold information relating to 20 percent of the waste that is generated in the region which reflects the complexity of the waste management system and differences in the way data has historically been collected across the region.
The Canterbury Joint Waste Committee (CJWC) commenced a regional data project in 2020 which aims to improve our understanding of the amount of waste in the region.
Waste minimisation
Rural communities do not always have the same access to waste management options as urban communities.
This limits options for waste minimisation and management higher up the waste management hierarchy.
It is estimated that up to 50 different types of waste are produced on farms and approximately 10 tonnes of non-natural waste are generated per farm each year.
National initiatives such as the New Zealand Rural Waste Minimisation Project have been successful in providing more sustainable waste management options for farm waste.
Aggregate quarries
Gravel quarries are typically large open pits, ~10+ metres deep. For the land to be used for other purposes following gravel extraction, rehabilitation of the quarry void typically requires backfilling to an elevation closer to the original land surface.
Backfill material is itself a valuable resource, so there can be a desire to use waste material to fill and rehabilitate quarries. Due to risks to groundwater quality where quarries are located over unconfined or semi-confined aquifers, quarry pits in these locations are generally not good sites for the disposal of waste.
Climate change impacts
The National Emissions Reduction Plan contains actions for the management of organic and refrigerant wastes to support the New Zealand/Aotearoa climate change mitigation strategy.
These actions include changes to the way these wastes are presently managed, and this is likely to require the provision of new infrastructure to support these changes. In conjunction with this, the Resource Management Reform programme will enable the future regional planning framework to consider the effects of greenhouse gas emissions on climate change.
As part of Aotearoa New Zealand’/Aotearoa first climate change adaptation plan, the Ministry for the Environment/ Manatū Mō Te Taiao is developing a national risk assessment tool to help councils identify where landfills may be exposed and vulnerable to the effects of climate change and associated natural hazards.
Current actions or approach
Waste minimisation schemes
There are many schemes for waste minimisation or collection of specific waste types, such as PlasBack, the Tyrewise initiative, and the New Zealand Rural Waste Minimisation Project. We support the national Agrecovery programme that facilitates the removal of unused hazardous substances, and particularly redundant persistent pesticides and agrichemicals from farms.
The graph shows the amounts of hazardous substance collected by the Agrecovery initiative in the region during 2020 and 2022.
Regional planning framework
The regional planning framework seeks to minimise waste generation by applying the waste management hierarchy.
The regional planning framework also supports the development of infrastructure needed to increase waste minimisation options and it provides for waste disposal to take place where alternative options are not available and the effects on the environment are acceptable.