Chapter 6: Waste

Overview of waste in New Zealand

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.

Recycling and landfills

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.

Hazardous waste flows and treatment of wastewater

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.

Present and future management

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.

This chapter provides an overview of the state of, and trends in, waste management in New Zealand since 1997. The chapter focuses on the disposal of solid waste to landfills, although information on other aspects of waste is also presented, including cleanfill disposal, waste recovery, and recycling. The chapter includes brief assessments of liquid waste including wastewater, sewage sludge, and hazardous waste.

What is waste?

The New Zealand Waste Strategy 2002 (see box ‘More about the New Zealand Waste Strategy 2002’) defines waste as any material – solid, liquid, or gas – that is unwanted and/or unvalued, and has been discarded or discharged by its owner (Ministry for the Environment, 2002).

Waste is generated in a variety of forms, and can also change its form over time.

Solid waste includes common household waste (including kitchen and garden waste), commercial and industrial waste, sewage sludge, construction and demolition waste, waste from agriculture and food processing, and mine and quarry tailings.

Liquid waste includes domestic wastewater (liquid kitchen, laundry, and bathroom waste), stormwater, used oil, and waste from industrial processes.

Gaseous waste comprises gases and small particles emitted from open fires, incinerators, and vehicles, or produced by agricultural and industrial processes. Once released, the effects of these gases and particles are hard to control. Gaseous wastes and their impact on air quality and the atmosphere are discussed further in chapter 7, 'Air' and chapter 8, ‘Atmosphere’.

Hazardous waste is solid, liquid, or gaseous waste that poses a risk to human health and the environment. It includes paint, medical waste, used oil, solvents, electronic waste, and toxic gases.

Waste in New Zealand

Solid waste

The character of New Zealand’s economic activity has important implications for our waste. The large proportion of our land that is dedicated to agricultural, horticultural, forestry, and other primary production, and our comparatively limited manufacturing and heavy industry, have a significant impact on the types of waste we both generate and dispose of in New Zealand.

Much of the solid waste generated in New Zealand is disposed of to landfills and cleanfills, although industrial waste such as that produced by agricultural, forestry, quarrying, and mining activities is generally disposed of on site.

Cleanfill sites accept material that, when buried, will have no harmful effects on people or the environment. This includes natural materials such as clay, soil and rock, as well as other inert materials such as concrete or brick.

Many of our landfills and cleanfills are owned and operated by councils, although managed on a commercial basis.

Large volumes of waste are also disposed of at privately owned and operated construction and demolition waste landfills. These landfills have local authority consents that allow them to accept cleanfill materials, as well as limited amounts of construction timber, green waste, plastics, and steel, depending on the consent conditions for the site.

Gaseous waste

Gaseous waste is primarily controlled by the resource consent process or national environmental standards under the Resource Management Act 1991 (see box ‘More about national environmental standards’). These national environmental standards include regulations that ban waste incineration at schools and hospitals, unless resource consent is granted to allow the discharge of the substance to the air. The regulations also prohibit the high-temperature incineration of hazardous waste, with the exception of some medical waste. Unlike many Organisation for Economic Co-operation and Development (OECD) countries, only a fraction of the waste produced in New Zealand is disposed of by incineration.

Hazardous waste

A significant portion of the hazardous waste produced in New Zealand is discharged in dilute form to municipal wastewater treatment systems. Other types of hazardous waste have to be exported for disposal because they cannot be safely treated and disposed of in New Zealand.

Liquid waste

Every day, 1.5 billion litres of domestic wastewater is discharged in New Zealand. By volume, liquid waste is our largest waste stream. Liquid waste is generally managed and disposed of in wastewater treatment plants. However, some liquid waste from diffuse sources – such as effluent that has leached from agricultural land – is not currently managed or controlled. Waste management legislation (see box ‘Waste legislation’) empowers councils to play a key role in waste management through their administering of the resource consent process.

Environmental and health effects of waste

Waste is not only unsightly, it can also pollute our water, air, and land unless it is adequately managed. Waste of all types can affect human health and the environment. The effects can be direct, such as high levels of air pollution that causes respiratory problems, (see chapter 7, 'Air') or indirect, such as contaminants in soils that reduce the productivity of land or affect the quality of food (see chapter 9, 'Land').

Inert wastes, such as those produced by earthworks, building, and demolition activities, do not usually affect the environment significantly.

Some waste can produce hazardous substances that cause asthma and other respiratory diseases, bacterial illnesses, birth defects, and cancer. Some hazardous waste, such as persistent organic pollutants (POPs), can be especially toxic. Persistent organic pollutants remain in the environment for long periods, are widely dispersed – usually by water or wind – and accumulate in the fatty tissue of people and animals.

Waste is of concern to many New Zealanders for many different reasons. For example, Māori have a particular concern about the way in which waste disposal degrades the mauri, or life force, of the environment. They consider the disposal of waste at wāhi tapu (sacred sites) to be particularly inappropriate.

Waste and the economy

Waste is the by-product of economic activity. Waste can be generated at different times during the material life cycle: when raw natural resources are extracted or harvested; when goods are manufactured or services produced; and when goods are packaged, transported, and consumed.

Waste generation can indicate the inefficient use of resources. Some business commentators consider waste to be a design flaw (Economist: Science Technology Quarterly, 2007). Studies have shown that up to 93 per cent of raw materials are discarded during processing and do not end up in saleable products, and that 80 per cent of saleable products are discarded after a single use (Von Weizsacker et al, 1997, in Ministry for the Environment, 2002).

Historically, the relationship between the amount of waste generated and economic growth has meant that the greater the wealth, the greater the consumption of goods and services (and the resources used to produce these), and the more waste produced. A 40 per cent increase in Organisation for Economic Co-operation and Development (OECD) gross domestic product since 1980 has been accompanied by a 40 per cent increase in municipal waste over the same period (Organisation of Economic Co-operation and Development, in Ministry for the Environment, 2002).

Internationally, a key goal is to ‘decouple’ waste generation from economic growth. Waste generation can be decoupled by:

• increasing the resource efficiency of goods and services by using fewer resources in production
• decreasing the resource intensity in the production of goods and services through improved processes, designs, and materials.

The efficient use of our valuable natural resources saves us money, reduces our impact on the environment, and ensures that our goods and services are competitive. Some international businesses, such as Wal-Mart in America, recognise the benefits of resource efficiency and have adopted zero-waste targets (Economist: Science Technology Quarterly, 2007).

The New Zealand Waste Strategy recognises the benefits that can be achieved by using our natural resources more efficiently. In particular, the strategy supports the ‘waste hierarchy’ – the ‘5Rs’ of reduction, reuse, recycling, recovery, and management of residual waste. Under this hierarchy, the reduction in the amount of waste generated is put ahead of all other forms of waste management (see box ‘More about the New Zealand Waste Strategy 2002’). The avoidance of waste generation is more economical than paying for waste to be reused, recycled, or treated and managed to final disposal.

Reuse, recycling, and recovery

The reuse, recycling, and recovery of much waste is often technologically feasible, but may be hampered by economic factors. These include:

• the relatively low cost of raw materials, which makes it difficult or impossible for reprocessed waste materials to compete in the market
• New Zealand’s small and dispersed population, which adds to the cost of collecting and transporting materials for recycling, reuse, and recovery
• the traditionally low cost of waste disposal
• the lack of a regulatory framework or strong market signals for more efficient resource use.

Despite the difficulties listed above, the recovery and reuse of waste that has some economic value is increasing in New Zealand. For example, a small but growing proportion of waste is being used to generate energy or heat, instead of being disposed of to landfills. The Used Oil Recovery Programme recovers half to two-thirds of all used oil in New Zealand. The oil is collected from oil producers, major industrial oil consumers, garages and workshops, then transported to Westport to fire kilns at the Holcim cement plant.

Public expenditure on waste management

In 2003, public expenditure on waste management in New Zealand amounted to $218 million, or about 0.16 per cent of gross domestic product (GDP). The management of wastewater cost an additional $603 million, or 0.45 per cent of GDP. Since 2001, the operation and maintenance of facilities for managing waste and wastewater have accounted for about 58 per cent of the total expenditure on waste and wastewater, with local authorities accounting for 99 per cent of that figure (Organisation for Economic Co-operation and Development, 2007).

See chapter 1, ‘Environmental reporting’, for more information on the core national environmental indicators and how they are used.

There is one national environmental indicator for reporting on waste in New Zealand: solid waste disposed of to municipal landfills.

This indicator tracks changes over time in the quantity and composition of the solid waste disposed of to landfills. It provides valuable information on waste flows, including the quantities and types of materials that can be recycled or recovered to avoid their disposal.

Limitations of the indicator

The indicator includes only solid waste disposed of to municipal landfills. It does not include disposal to cleanfills or other disposal sites, such as construction and demolition waste landfills. Liquid, gaseous, and hazardous wastes are not specifically measured by the indicator (although hazardous waste is included in estimates of solid waste disposed of to landfills).

The indicator does not measure any activities aimed at minimising waste and increasing resource efficiency, such as improvements to production methods. Nor does it measure the decoupling of waste generation from influencing factors, such as population and economic growth.

To present a wider picture of waste disposal in New Zealand, this chapter also draws on information about landfills, cleanfills, waste recovery and recycling, liquid waste including wastewater, sewage sludge (biosolids), and hazardous waste.

It is estimated that around 8.7 million tonnes of solid waste (from domestic, commercial, industrial, and institutional waste sources) was generated in New Zealand in 2006, of which 2.4 million tonnes was subsequently diverted from disposal to landfills (Waste Not Consulting, 2006). This means that approximately 6.3 million tonnes of waste are sent to landfill and cleanfill sites each year. When averaged across the total population, that represents 1,572 kilograms of solid waste per person per year.

Waste to landfill

Waste volumes

Estimates of the total quantities of solid waste disposed of to landfill in New Zealand since 1990 are shown in Figure 6.1. Estimates have varied significantly since 1990, partly as a result of the changing quality of available waste data.

Figure 6.1 shows that the estimated amount of solid waste disposed of to landfill in New Zealand decreased slightly from 1995 to 2006, from 3.180 million tonnes or 898 kilograms per person per year in 1995, to 3.156 million tonnes or 784 kilograms per person per year in 2006. During this period, New Zealand’s wealth, expressed as real gross domestic product (GDP) (adjusted for inflation), increased by 40 per cent, largely as a result of expansion in the economic sectors that are major sources of waste (for example, agriculture, manufacturing, transport, tourism, energy, and construction).

Converted to tonnes of waste disposed of to landfills per thousand dollars of GDP, the estimated waste disposed of in 2006 was 29 per cent lower than in 1995 (New Zealand Institute of Economic Research, pers comm). This decrease indicates a decoupling from economic growth of waste disposal to landfills. However, it is not known whether this decrease was accompanied by an increase in the waste disposed of to cleanfills or other disposal sites, such as construction and demolition waste landfills.

Although construction and demolition waste landfills are not consented to accept domestic, liquid, or hazardous waste, these landfills are thought to accept large quantities of the total waste disposed of in some areas of New Zealand.

Figure 6.1 shows that the amount of waste disposed of to landfills annually since 1998 has stabilised. This trend coincides with an increase in the availability of waste recovery initiatives and recycling services throughout New Zealand. At the same time, the proportion of local authorities applying user charges for landfills has now reached 93 per cent. User charges act as an incentive to reduce waste disposal to landfills.

Figure 6.1: Estimates of waste disposed of to landfill, 1983–2006, and number of landfills operating, 1995–2006

Landfill management

Figure 6.1 shows that the number of landfills operating in New Zealand decreased from 327 in 1995 to 60 in 2006. This decrease is partly the result of a drive to improve the performance and management of landfills through the stronger environmental controls provided by the Resource Management Act 1991, national environmental standards, and best practice guidelines for landfill management. The decrease is also likely to reflect the introduction of user charges to landfills and the consolidation of some waste management operations.

Landfill management practices have greatly improved in the last decade. The proportion of landfills with an engineered liner (liners help to minimise leachate entering and contaminating surface and groundwater systems) rose from 4 per cent in 1998 to 54 per cent in 2006, while those that collect potentially hazardous landfill leachate rose from 13 per cent in 1995 to 77 per cent in 2006.

The proportion of landfills that collect methane gas and use it to generate energy has increased from 5 per cent in 1998 to 23 per cent in 2007. At larger landfills, this shift reflects new landfill gas management requirements under the national environmental standards. It also reflects a growing recognition of the benefits of reusing this potentially valuable waste gas.

Waste composition

No comprehensive data is available on the composition of solid waste disposed of to landfills in New Zealand. However, data from 16 waste facilities (representing more than 50 per cent of the waste disposed of to landfills in New Zealand) can be used to provide a ‘snapshot’ (see Figure 6.2) of waste composition (Waste Not Consulting, 2006). The percentages shown are indicative only, because the margin of error associated with analysing the composition of waste disposed of to landfills is typically 20 per cent.

Figure 6.2 indicates that nearly a quarter of the waste received at municipal landfills consists of organic material (23 per cent). Paper comprises 15 per cent, timber 14 per cent, and rubble and concrete 12 per cent. Potentially, these waste types can be diverted from landfills for reuse or reprocessing.

Figure 6.2: Estimates of the composition of waste disposed of to landfills, 2004

Waste to cleanfill sites

Cleanfill sites accept materials that, when buried, will have no harmful effect on people or the environment. These materials include natural materials that are free of combustible, biodegradable, or leachable components; hazardous substances; or liquid waste. The materials are also free of substances that may present a risk to human or animal health, such as medical and veterinary waste, asbestos, or radioactive substances.

Cleanfills are a permitted activity in many regional and district plans, provided they meet specified criteria. Because cleanfills are a permitted activity, only limited monitoring of them takes place. In addition, many cleanfills are commercially operated, and information about them is therefore considered to be commercially sensitive. Regional councils and territorial authorities estimate that there may be more than 300 cleanfills in New Zealand, although the actual number is not known.

From available information, it is estimated that between 0.65 to 0.91 tonnes of waste are disposed of to cleanfills in New Zealand for each person every year (Waste Not Consulting, 2006). From this estimate, the total amount of waste disposed of to cleanfills in New Zealand each year can be estimated at between 2.7 to 3.7 million tonnes per year. This amount is about the same as that of solid waste disposed of to landfills.

Recovered materials

The uptake in recycling in New Zealand has increased significantly over the last decade, as a result of major recovery and recycling initiatives that have been introduced to divert materials from going to landfills and cleanfills. These initiatives range from the recycling and composting services offered by local authorities and community-based groups, to industry-led recovery and recycling, and product stewardship schemes (see box ‘More about product stewardship’).

In 2005, municipal recycling diverted 329,283 tonnes of paper, plastic, glass, steel, and aluminium from landfills. When commercial waste is included, the total amount of material diverted from landfills each year in New Zealand is estimated to be about 2.4 million tonnes a year.

Industrial recovery and recycling

Estimates of the amounts of some industrial waste diverted from landfills and cleanfills are shown in Table 6.1. However, the figures do not include:

• materials diverted from one business to another
• materials recovered and reused during commercial operations, such as the on-site recovery and reuse of building materials.

Table 6.1: Estimates of industry waste diverted from landfills and cleanfills annually

Source: Ministry for the Environment, 2007c.

Community recycling

As noted earlier, territorial authorities diverted an estimated 329,283 tonnes of glass packaging, scrap metal, plastics, and paper from landfills in 2005–2006, through kerbside recycling and drop-off centres.

Overall, 73 per cent of New Zealanders had access to kerbside recycling in 2006, up from 20 per cent in 1996, while 97 per cent of New Zealanders had access to either kerbside or drop-off recycling services. For New Zealanders with access to recycling services, 83 kilograms of waste per person was diverted to recycling each year.

Table 6.2 shows the availability of recycling services provided by territorial authorities in metropolitan, urban, and rural areas.

Table 6.2: Recycling in metropolitan, urban, and rural areas, 2006

Note: Metropolitan area include Auckland, Hamilton, Wellington, Christchurch, and Dunedin

Source: Ministry for the Environment, 2007c.

Business and community initiatives

Throughout New Zealand, a large number of non-government organisations have set up programmes to work with the community to reduce waste and promote recycling and resource efficiency. These organisations include professional and industry associations, and not-for-profit organisations such as the Waste Management Institute of New Zealand, New Zealand Business Council for Sustainable Development, Sustainable Business Network, Packaging Council of New Zealand, and Zero Waste New Zealand Trust. The programmes also include a significant number of community-based recovery and recycling centres, which make an important contribution to the quantities of waste that are reused, recycled, and recovered in New Zealand.

Organic waste

Organic waste includes food (kitchen) waste, animal and human sewage waste, and garden waste. The agricultural and food and beverage sectors generate a large proportion of New Zealand’s organic waste. It also originates from wastewater treatment plants in the form of sewage sludge. Organic waste in landfills decomposes in the absence of oxygen, generating methane (a greenhouse gas), which contributes to climate change. Organic waste in landfills also creates leachate, which has the potential to contaminate surface and groundwater systems.

Only a small proportion of the organic waste produced in New Zealand is handled by territorial authorities. However, councils diverted an estimated 312,085 tonnes of organic waste from landfills in 2005–2006. Kitchen and garden waste made up 92 per cent of the total amount diverted (Ministry for the Environment, 2007c).

A 2004 survey estimated that organic waste represented 23 per cent, or 743,324 tonnes, of all waste disposed of to landfills (Waste Not Consulting, 2006) (see Figure 6.2). Notably, this percentage has reduced from 47 per cent according to a survey in 1995 (Ministry for the Environment, 1997). Even so, the 2004 result illustrates that potentially recoverable organic material continues to be disposed of to New Zealand landfills.

In 2005–2006, it was estimated that 153,885 tonnes of garden waste was diverted from landfills by territorial authorities. Garden waste is most commonly composted or mulched at transfer stations and some landfills. More than 70 per cent of local authorities provide this service.

New Zealanders compost an unknown quantity of food and garden waste at home.

Wastewater disposal

Wastewater, which is made up of sewage, some stormwater and liquid trade waste, is usually very dilute. Domestic wastewater is discharged into the environment at a rate of approximately 1.5 billion litres a day (Ministry for the Environment, 2007d). Wastewater has the potential to physically alter and contaminate the environment into which it is discharged (that is, the sea or other waterways; see chapter 10, ‘Freshwater’ and chapter 11, ‘Oceans’ for further details).

Most domestic and commercial wastewater in New Zealand is treated at one of 320 public wastewater treatment plants before being discharged into the environment. Domestic wastewater is managed by septic tanks for 15–20 per cent of the population (Ministry for the Environment, 2005). Many industrial plants have their own wastewater treatment or pre-treatment facilities.

The degree of treatment, and the resulting quality of the treated wastewater, varies widely from plant to plant. Most wastewater treatment plants use primary treatment, which is the physical removal of both organic and inorganic solids. Of the 269 plants for which information is available, 56 per cent employ secondary treatment to remove solids and associated contaminants (Ministry for the Environment, 2005). Another 36 per cent have tertiary treatment (the final stage in treating wastewater), which typically involves the removal of substances such as nitrates and sometimes includes disinfection of the water.

About half of the 125 public wastewater treatment plants for which information is available discharge treated sewage into rivers and streams. About a quarter of them discharge into the sea (either long sea outfall or near shore outfall). The remainder discharge onto land or wetlands, estuaries, or into groundwater (see Figure 6.3).

Figure 6.3: Receiving environments for wastewater discharged from 125 treatment plants, 2007

The Resource Management Act 1991 requires all wastewater treatment facilities to have consent to operate, and to meet relevant discharge standards for the receiving environment. As consents are renewed, the performance of each plant is reassessed. This process has significantly improved the standard of wastewater discharges around New Zealand, and is supported by best practice guidance for wastewater treatment.

More about trade waste bylaws

More than 89 per cent of local authorities have a trade waste bylaw. This enables them to set limits on discharges by industries and businesses to municipal wastewater. This helps protect reticulation and treatment systems, and the health and safety of workers, and ensures resource consent conditions are met. Many authorities use the Model Trade Waste Bylaw (NZS9201:23) as an example to develop their bylaws. Bylaws may also be used to regulate the pre-treatment of wastes at source, and to minimise the organic, nutrient, and contaminant levels in wastewater.

Sewage sludge

Each year in New Zealand, wastewater treatment plants generate 234,112 tonnes of sewage sludge. About 66 per cent of this is diverted from landfills to be reused in some way (Ministry for the Environment, 1997).

Detailed information on the generation of sewage sludge is available for 26 municipal treatment plants, which serve nearly 30 per cent of the population. These monitored plants divert an estimated 155,000 tonnes of wet and dry sewage sludge from landfills each year, which is reused in some way, as shown in Figure 6.4.

Most of the sewage sludge that the monitored plants divert is used to reclaim land (116,380 tonnes). Other uses include applying sludge to forested land as a fertiliser (600 tonnes), making compost (included in the 36,817 tonnes figure for ‘other beneficial reuse’), and pond storage (875 tonnes).

Figure 6.4: Sewage sludge from monitored treatment plants, 2006

The diversion of sewage sludge from landfills is important because it reduces pressure on space in the landfills and extends their lifespan. A further advantage of this diversion is that less methane is generated. In some communities, sewage sludge can account for between 5 and 10 per cent of all waste sent to landfills.

Upgrades to wastewater treatment plants around New Zealand will result in greater quantities of sewage sludge being produced. For example, after a recent upgrade to the Mangere wastewater treatment plant in Auckland, the volume of solids removed from wastewater increased from 40,000 tonnes in the mid-1990s to 116,000 tonnes a year in 2005–2006 (Ministry for the Environment, 2007c). While a significant portion of these solids will be able to be reused, an increasing quantity will not, because it will have unacceptable contamination levels. This highlights the importance of reducing and pre-treating liquid waste (especially hazardous industrial waste) at source before it is disposed of through the wastewater system.

Hazardous substances

Hazardous substances are those that can cause damage to human health or the environment. They may be explosive, flammable, toxic, or corrosive, or accelerate the combustion of other materials. They may also be eco-toxic (toxic to the environment). Most hazardous substances have more than one hazardous property. For example, petrol is flammable, toxic, and eco-toxic.

Many of the chemicals we use in our daily lives are hazardous substances. These include common household chemicals (for example, bleaches), solvents, paints, adhesives, swimming pool chemicals, and petroleum products.

Hazardous substances can enter the environment in a variety of ways, for example, as a result of emissions from burning fossil fuels; as industrial and municipal wastewater discharges; as stormwater run-off; or as by-products of activities such as agriculture, mining, manufacturing, chemical transport, or landfills.

Whatever the source and route into the environment, there is a risk that hazardous substances may be absorbed by humans and other living things. The most common ways that humans are exposed to hazardous substances are through inhalation, absorption through the skin, or ingestion.

Use of hazardous substances in industry

In the past, hazardous substances were commonly used in New Zealand’s agricultural, horticultural, mining, and forestry sectors. As an example, pesticides and other agrichemicals were widely used to increase the economic returns from farmed or cropped land. They were often used with little or no equipment to protect human health.

The use of agrichemicals continues today, but protective practices have improved, and the toxicity levels of many agrichemical products have been reduced. As a result, the levels of agrichemical residues in our food have dropped. A 2003–2004 survey of 100 New Zealand foods found that agrichemical residues were detectable in 50 per cent of the sampled foods, down from 59 per cent in a 1997–1998 survey. In both surveys, the levels of chemical residues detected were well within acceptable limits (New Zealand Food Safety Authority, 2006).

Hazardous substances are used extensively in a number of other sectors. Small and medium enterprises are estimated to make up more than 96 per cent of all businesses in New Zealand. Many of these businesses use, transport, store, or sell hazardous substances (for example, solvents, acids, and heavy metals).

Health effects of hazardous substances

The use of hazardous substances can affect our health. Approximately nine deaths and 773 hospitalisations occur each year as a result of short-term exposure to hazardous substances (Ministry for the Environment, 2007b), mostly as the result of accidents. It is estimated that long-term exposure to hazardous substances causes at least 400 premature deaths and a further 300 cancers each year in New Zealand (Driscoll et al, 2004).

In addition, more than 40 per cent of incidents involving hazardous substances result in some kind of environmental pollution (Environmental Risk Management Authority, 2006).

Regulatory controls

Given the need to protect both human health and the environment, New Zealand closely controls hazardous substances. The Hazardous Substances and New Organisms Act 1996 and associated regulations set rules for managing the risks linked with the manufacturing, use, storage, transportation, and disposal of hazardous substances, including those used in the agricultural sector. These controls are in line with international commitments that New Zealand has made to manage hazardous substances (for example, the Stockholm Convention on Persistent Organic Pollutants).

The Resource Management Act 1991 regulates the environmental effects of discharges, including waste disposal and the discharge of hazardous substances. These effects can be managed through resource consent conditions, rules in council plans, and national environmental standards. In this way, territorial authorities and regional councils can prevent or mitigate any adverse effects arising from the disposal of hazardous substances.

Hazardous waste

When hazardous substances reach the end of their useful life, they can become hazardous waste that requires careful handling and disposal. Hazardous waste can take a variety of forms – liquid, sludge, solid, and gas, and can be managed in a variety of ways, for example, at wastewater treatment plants or through the used oil recovery programme. Private sector waste operators play a key role in the treatment and disposal of hazardous waste.

A key issue in New Zealand is that most hazardous waste is mixed either at source or during its transport, treatment, or disposal. As a result, treatment and disposal is made more difficult and opportunities for hazardous waste to be recovered and recycled are reduced.

Information on hazardous waste is limited in New Zealand, because of a lack of formal record keeping and reporting on waste flows in the past. As well as this, a significant proportion of hazardous waste is handled by private waste operators, whose data is considered commercially sensitive.

The information available about hazardous waste primarily relates to specific waste streams, such as those for electronic equipment, agrichemicals, end-of-life vehicles (vehicles that have come to the end of their useful life), and waste oil.

Disposal of hazardous waste

By volume, most hazardous waste is discharged to the sewerage system, to be treated and disposed of in municipal wastewater treatment plants. A recent hazardous waste survey estimated that 72 per cent of the hazardous waste in the Bay of Plenty region, and 85 per cent in the Waikato region, was disposed of to sewers (Environment Bay of Plenty, 2004).

In 2004, solid hazardous waste was estimated to account for 11 per cent of the waste disposed of to landfills (Waste Not Consulting, 2006). About a quarter of this waste is rendered inert (stabilised) before disposal at waste treatment facilities.

Several major industries – for example, the mining industry – treat and dispose of hazardous waste independently.

Used oil is generated at a rate of 33 to 40 million litres in New Zealand each year (Slaughter et al, 2007). In 1997, 77 per cent of used oil was dumped to landfills, burned, poured onto roads to control dust, used to lubricate chainsaws and stain fences, or lost or discarded in various unknown ways (Ministry for the Environment, 1997). Today, the Used Oil Recovery Programme collects and reuses 21 million litres of used oil a year.

Waste electrical and electronic equipment (including products such as batteries, computers, cell phones, and televisions), and lighting appliances (such as fluorescent tubes), are disposed of to landfills in New Zealand every year at a rate of up to 80,000 tonnes (Ministry for the Environment, 2007c). Several schemes to reuse, recycle, or recover waste electrical and electronic goods have been introduced in New Zealand.

End-of-life vehicles can cause a waste problem even if they are sent to the scrap yard. Various hazardous substances, such as used oil, refrigerants, batteries, and circuit boards, must be removed from end-of-life vehicles for appropriate treatment or disposal. Approximately 25,000 cars are dumped illegally in New Zealand each year, at a cost to authorities of $6 million (Ministry for the Environment, 2007a).

The 1997 report, The State of New Zealand’s Environment 1997, concluded that:

In many cities the amount of recycling has increased, in some places landfill fees have been raised, and cleaner production is being attempted by some organisations.…

While waste management responses increasingly include recycling, cleaner production systems and higher landfill fees, total waste has increased, our landfill management practices are generally poor, as are our practices and attitudes towards managing hazardous waste.

Waste disposal and management

Since the 1997 report, significant gains have been made in New Zealand in managing the effects of waste on human health and the environment. These have been driven primarily by stronger controls on waste disposal and management under the Resource Management Act 1991, the Hazardous Substances and New Organisms Act 1996, and the Local Government Acts (1974 and 2002).

In response to these controls, the management and environmental performance of both landfills and wastewater treatment plants in New Zealand has significantly improved over the last decade. The number of landfills in New Zealand has decreased, from 327 in 1995 to about 60 in 2007, with substandard landfills having closed.

As at 2007, 56 per cent of the 269 wastewater treatment plants for which information is available operate secondary treatment for wastewater, and 36 per cent treat their wastewater to the highest level (tertiary treatment). As a result, the quality of wastewater discharged to the environment has improved significantly since 1997.

In addition, most local authorities now have in place trade waste bylaws to manage the effects of industrial waste on the quality of wastewater.

While hazardous waste flows are still not well understood because of the lack of available data, hazardous substances and their wastes are now better controlled through the Hazardous Substances and New Organisms Act, trade waste bylaws, and national environmental standards.

The New Zealand Waste Strategy

In 2002, the New Zealand Waste Strategy came into effect, providing the strategic direction for waste management and minimisation in New Zealand. It set several targets to improve the management and minimisation of wastes, including those considered to be priority wastes, such as hazardous waste.

However, progress against the 30 waste strategy targets has been variable. Good progress has been made in community recycling and ‘green waste’ schemes, through central government’s engagement with businesses, and guidelines to improve the management of landfills and hazardous waste. Less progress has been made in diverting commercial organic, and construction and demolition waste from landfills; improving the management of cleanfills; and identifying and managing contaminated sites. Progress against several targets was unable to be measured.

Local government responsibilities

Both the Local Government Act 2002 and the New Zealand Waste Strategy have clarified and formalised the role of local government in managing and minimising waste. Each territorial authority is required to prepare a waste management plan to address the reduction, reuse, recycling, recovery, and treatment and disposal of waste in the district.

Territorial authorities continue to have responsibility for collecting municipal waste, and for operating kerbside recycling and drop-off centres, transfer stations, and sanitary municipal landfills. Councils also play an important part in raising awareness of the benefits of minimising waste and recycling.

Commercial involvement

A commercial waste industry has developed since 1997, which has allowed market forces to operate for waste disposal and recovery.

As a result of the commercialisation of the waste sector, important progress has been made towards charging full costs for waste disposal and management since 1997. This has boosted efforts by industry to use resources more efficiently to reduce the generation and subsequent disposal of waste.

Waste minimisation and resource efficiency

The development of the New Zealand Waste Strategy and its targets illustrates a shifting focus away from controlling the effects of waste disposal towards:

• minimising the amount of waste requiring disposal
• increasing how efficiently valuable resources are used.

A significant number of government, private industry, and community-based initiatives are now working towards wider waste minimisation and resource efficiency goals. In particular, producers are taking greater responsibility for reducing their waste.

Several sectors are now involved in industry-led product stewardship schemes that enable manufacturers, brand owners, importers, and retailers to reduce the environmental effects of products, from the manufacture of products through to their disposal. One example is the 2004 New Zealand Packaging Accord, which sets several waste minimisation targets for participating sectors, and monitors progress against them.

Government agencies have also taken on greater responsibility for their waste. The introduction of the Govt3 programme in 2003 has enabled 48 government departments and other agencies to show leadership in waste minimisation.

Trends in solid waste

Partly in response to initiatives such as those described above, the total amount of waste disposed of to landfills in New Zealand has stabilised between 1995 and 2006 and, in fact, has decreased by 29 per cent when measured against the economic growth New Zealand has experienced (that is, in terms of real gross domestic product).

However, it is not known whether this stabilisation was accompanied by an increase in waste disposed of to cleanfills or other disposal sites. The stabilisation has coincided with the establishment of municipal and industry-led recycling and recovery programmes in many parts of the country. Seventy-three per cent of New Zealanders now have access to kerbside recycling, and 97 percent have access to either kerbside or drop-off recycling services.

Since 1997, there have been significant increases in the amounts of material recovered from the waste stream, and recycled, or reprocessed. The total amount of material diverted from landfills and cleanfills is estimated to be about 2.4 million tonnes a year.

As in 1997, many potentially useful materials continue to be disposed of to New Zealand landfills and cleanfills. Organic waste, timber, and construction and demolition waste make up nearly 50 per cent of the waste disposed of to landfills. Much of this waste could be recycled, reused, or reprocessed in some way. However, the evaluation of waste flows in New Zealand is still hampered by a continuing lack of standardised reporting and monitoring systems, and a resulting lack of reliable waste data.

Present and future management

With environmental sustainability now a global focus, increased attention is being given to minimising the amount of waste generated and disposed of by businesses, households, and communities. This trend reflects an international drive to use valuable natural resources more efficiently, and to reduce costs. It also coincides with global pressures to respond to climate change by reducing the greenhouse gas emissions from waste (see chapter 8, ‘Atmosphere’).

In the future, waste policy in New Zealand is likely to continue to focus on minimising the generation and disposal of waste. A further challenge will be to monitor waste flows better, and to reduce waste throughout the life of products, through their ‘greener’ design. Consumer purchasing choices and an increased availability of ‘lower waste’ goods will largely influence the extent to which this minimisation and reduction of waste will occur.

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Economist: Science Technology Quarterly. 2007. The Truth about Recycling. Retrieved from http://www.economist.com/PrinterFriendly.cfm?story_id=9249262 (17 July 2007).

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Ministry for the Environment. 2002. New Zealand Waste Strategy 2002: Towards zero waste and a sustainable New Zealand. Wellington: Ministry for the Environment.

Ministry for the Environment. 2004. Review of Targets in the New Zealand Waste Strategy. Wellington: Ministry for the Environment.

Ministry for the Environment. 2005. Waste Management in New Zealand: A decade of progress. Wellington: Ministry for the Environment.

Ministry for the Environment. 2007a. Special wastes: end-of-life vehicles. Retrieved from Ministry for the Environment website (13 May 2007).

Ministry for the Environment. 2007b. Surveillance of Harms Resulting from Exposure to Hazardous Substances. Part 1: Attributing Acute Hazardous Substance Exposures to Incidents Causing Injury or Death, report to Ministry for the Environment, Graham Environmental Consulting Ltd. Wellington: Ministry for the Environment.

Ministry for the Environment. 2007c. Targets in the New Zealand Waste Strategy: 2006 review of progress. Wellington: Ministry for the Environment.

Ministry for the Environment. 2007d. Wastewater. Retrieved from Wastewater: how wastewater is managed in New Zealand (25 April 2007).

New Zealand Food Safety Authority. 2006. 2003/04 New Zealand Total Diet Survey Agricultural Compound Residues, Selected Contaminants and Nutrients. Wellington: New Zealand Food Safety Authority.

Organisation for Economic Co-operation and Development. 2007. OECD Environmental Performance Reviews: New Zealand. Paris: OECD Publishing.

Slaughter, G et al. 2007. New Zealand Used Oil Recovery Programme: Best available technology for processing used oil? Abstract for presentation at 14th IUAPPA World Congress. Retrieved from http://www.iuappa2007.com/abstract/295.htm (13 May 2007).

Waste Not Consulting. 2006. Waste Composition and Construction Waste Data, unpublished, prepared for the Ministry for the Environment. Wellington: Ministry for the Environment.

Waste Information, 2007. Wastewater Information Database. Retrieved from http://www.winfo.org.nz (16 April 2007).