Waste represents an inefficient use of our resources. Improperly disposed of, waste can also pose a risk to human health and the environment.
The amount of waste generated in New Zealand has increased over time as our population and levels of production and consumption have grown. However, in recent decades, the amount of waste recovered from the waste stream to be reused, recycled, or reprocessed has increased.
The amount of solid waste disposed of to New Zealand landfills has reduced slightly from an estimated 3.180 million tonnes in 1995 to 3.156 million tonnes in 2006. Converted to tonnes of waste disposed of to landfill per thousand dollars of gross domestic product (GDP), the estimated waste disposed of in 2006 was 29 per cent lower than in 1995. The shift to increased recycling and reprocessing, and the introduction of user-charges to dispose of waste, has helped reduce the amount of waste disposed of to landfills.
In 1995, 327 landfills were in use in New Zealand. Many of these had poor environmental controls. Today, there are about 60 landfills in use. Of these, 54 per cent use engineered liners (these help minimise leachate entering and contaminating surface and groundwater systems), 77 per cent collect leachate (liquid produced in landfills through the decomposition of waste), and 23 per cent recover landfill gas. New Zealand also has about 300 cleanfills across the country; these sites accept material that is not harmful to the environment when buried.
Recycling rates are increasing. In 2006, 73 per cent of New Zealanders had access to kerbside recycling, up from 20 per cent in 1996, and 97 per cent had access to either kerbside recycling or drop-off centres.
In 2005, 329,283 tonnes of paper, plastic, card, glass, steel, and aluminium collected through municipal recycling were diverted from being sent to landfills. When commercial waste is included, the total amount of material diverted from landfills is estimated to be about 2.4 million tonnes a year.
However, despite these advances, many potentially useful materials continue to be disposed of to New Zealand landfills and cleanfills. Organic (mostly garden and food) waste, timber, and construction and demolition waste make up nearly 50 per cent of waste disposed of to landfills.
Quantities of hazardous waste are not yet well understood in New Zealand because of a lack of available data. A significant portion of hazardous waste is liquid and disposed of to the sewerage system, where it is treated at one of the country’s 320 wastewater treatment plants.
Wastewater treatment plants discharge approximately 1.5 billion litres of domestic wastewater daily into the sea and other waterways, and onto land. Sewage sludge (biosolids) is removed from the wastewater during treatment and has, traditionally, been disposed of in landfills. Each year, wastewater treatment plants, serving almost 30 per cent of the country’s population divert about 155,000 tonnes of sewage sludge to beneficial uses such as land reclamation, application to forested land as fertiliser, and blending with green waste to produce compost.
Since 1997, waste management in New Zealand has focused on managing the human health and environmental effects of waste, primarily by putting in place standards for waste disposal.
Today, many businesses, householders, and communities are paying greater attention to minimising the amount of waste they generate and dispose of. This reflects an international shift towards using valuable natural resources more efficiently, and reducing the costs associated with production and disposal of waste. Producers are also taking greater responsibility for reducing the environmental effects of their products, from manufacture to disposal. Consumer purchasing choices will increasingly drive the 'green design' of products, including products which produce less waste throughout their life cycle.
In the future, the minimisation of waste generation and disposal is likely to remain a focus for New Zealand. In particular, attention is likely to focus on reducing the levels of potentially valuable wastes such as organic waste, construction and demolition waste, and some hazardous wastes. A further challenge is to improve the monitoring of waste flows.