Organic Waste Management
Waste specifically refers to any type of material sought for disposal or discard (Waste Minimisation Act, 2008). The sub-component organic waste will consist of garden greens or ‘green waste’, and kitchen waste for the purpose of the following investigation. The accumulation of waste comes from a fundamental disregard of appropriate thinking and the inefficient use of our resources (Seadon, 2010 and State of the Environment Report, 2007). Not only does traditional waste disposal pose a loss in economic wealth through an inability to utilise materials and capitalise on their benefits, but also inappropriate disposal creates potential risk to human health and environmental pollution (New Zealand Waste Strategy, 2010). This research seeks to identify the overall level of effective management and current state of urban organic waste in New Zealand. In particular this will be achieved through an examination of environmental indicators and initiatives such as the legislative framework, collection options and services, landfill operation, along with public opinion and response. Six major cities will be investigated to give a varied account of the overall state of New Zealand’s progress in this area.
- (Image source Organic-Banana-Waste, 2010)
About Organic Waste
What is organic waste?
Organic waste refers to any material originating from once-living plants or organisms (Donkin, 2011), which is transformable into compost when subject to aerobic or anaerobic decomposition processes (Wadkar et al, 2013). This includes the kitchen scraps and green waste produced by individual households through to large scale agricultural by-products. The term 'waste' is a bit of a misnomer when used to describe organic material and merely reflects societal attitudes towards the reuse and recycling of the Earth's resources. There is in fact no defining end point for organic matter, where once-living biomass is transformed from a readily identifiable resource (i.e. food, garden plants) to an equally valuable product (i.e. compost) to be spread over gardens to increase nutrient levels and promote plant growth.
How does it work?
Aerobic composting occurs in the presence of oxygen interacting with organic compounds to produce carbon dioxide for further energy use, and nitrite and nitrate which are recycled (Wadkar et al, 2013). This system is a dynamic and naturally occurring cycle by way of continual reformation and servicing. On the other hand, anaerobic digestion involves a number of processes where organic matter is composted through the absence of oxygen. Considerable amounts of methane and carbon dioxide are produced during anaerobic digestion which can have detrimental effects on the environment. These also serve as a final output with no further ability to utilise organic waste as a resource (Wadkar et al 2013).
Why is organic waste an environmental issue?
Organic waste takes up valuable space in the landfill, where the potential benefits of such a resource are permanently lost. By-products of the anaerobic decomposition process occurring here include the production of leachate and methane which have detrimental effects on the environment (Themelis and Ulloa, 2007). This includes potential contamination of waterways, soils, and air that increased toxicity levels in neighbouring areas, whilst methane is an important greenhouse gas involved in climate forcing (Themelis and Ulloa, 2007). Mitigation of these effects can be achieved through proper disposal and processing of organic waste and as the separation of organic material from the main waste stream could be easily implemented at the household level through education and provision of services to accommodate organic waste. There is considerable potential for more efficient use of this resource.
Landfill composition data
Waste has been identified as one of the four main indicators for the state of New Zealand's environment (Environmental reporting on New Zealand’s waste; MfE, 2013). The quantity and composition of waste to landfill is the only nationally recognised indicator as a monitoring method (Environmental indicator for waste: Solid waste disposal; MfE, 2013).
Organic waste is the largest singular component of material appearing in landfills and accounts for 28 percent of all waste (Environmental Report Card, 2009). There is no separate monitoring indicator to trace the state of organic waste in New Zealand. Aside from the national indicator, some local authorities have had taken initiative in identifying their own waste indicators to gain knowledge and data of localised organic waste consumption. For example Nelson conducts a consumer behaviour survey every three years to gain insight into the way people are minimising their waste activities. Each year they report on diverted material types that are handled by the council and to the best of their ability private companies, along with kerbside service satisfaction surveys, inquiries received, and the number of households that carry out home composting (Nelson City Council/ Tasman District Council, 2012). By international standards the OECD believes that indicators should work in conjunction with others to give more holistically complete information and highlight data gaps. With this, suggestions to provide a greater level of supervision in managing waste options for the complete life cycle of material would better allow for appropriate use and reuse of the resource (OECD Environment Directorate, 2008). For New Zealand, this provides considerable incentive to create a thriving and efficient approach for dealing with organic waste. For example, New Zealand provides a substantially high success rate in kerbside recycling. 73 percent of people have kerbside available for recycling options, while 97 percent are able to access some form of recycling whether it be kerbside or drop-off facilities. This applies primarily to materials such as paper, plastic, glass, and steel (State of the Environment Report, 2007). These initiatives are a positive direction for the future, unfortunately the resource abundant potential of organic waste collection are still largely left untouched and currently continue to contribute amongst timber and construction up to 50% of landfill composition (State of the Environment Report, 2007).
Attitudes from the public towards generation, recycling and removal of waste are significant indicators for the state and importance of organic waste in New Zealand society. With the implementation of kerbside recycling services alongside general waste collection there has not only been a increase in overall participation but there is now an expectation that such services be provided and will continue to evolve (Christchurch City Council, 2013). Many rural citizens have compost facilities on their properties whilst those in urban areas often lack the yard space for such a system and thus the concept of separating organics from mainstream household refuse is not regularly considered in these situations. A contact at the Green Island Landfill, Dunedin highlighted the importance for landfill services to accommodate customer needs and identify how these implementations can change customer behaviour. For example, raising disposal costs and providing cheaper alternatives for dumping green waste encourages customers to minimise and separate their waste load.
Whilst over the last decade New Zealand has seen a slight reduction in the volume of waste sent to landfill, the organic waste component has increased and remains a significant proportion of the waste stream (Environment New Zealand, 2007).
The first recorded data on the composition of landfill was in 1995, with the Landfill Census Report (National Landfill Census Report,1998.1999). Here they began to raise questions as to the impact landfills were having on both the environment and people (National Landfill Census Report, 1998/1999). The report emerged as a direct result of the implementation of the Resource Management Act 1991 (RMA). This legislation put statutory pressure on the way landfills carry out their waste management practises with regards to environmental implications (National Landfill Census Report, 1998/1999). Three years later a follow up report was conducted between 1998 and 1999 called the National Landfill Census Report, which sought to determine the progress reached from the previous report (National Landfill Census Report, 1998/1999). In contrast, the second report moved from simply defining the need for better management, to indicating concise framework systems for mitigation environmental problems surrounding landfills. These included, leachate collection, gas collection and management, and specification standards for waste entering landfill (National Landfill Census Report 1998/1999).
Information from New Zealand's first State of the Environment review revealed that prior to the 1950’s little organic waste was entering into landfill, which only tended to be more small operational quarry infills, coastal gullies and wetland areas (Ministry for the Environment, 1997). With this in mind, reliable data is hard to determine as many small landfill operations lacked any appropriate monitoring programs and were considered to be managing high risk sites (Ministry for the Environment, 1997). For example Auckland City Council ordered the closure of 85 landfills that had been in operation between 1910 and the 1970’s due to conclusion of their harmful risks to human health and the environment. It was not until after the 1950’s that organic waste was considered to be significantly directed to landfill (Ministry for the Environment, 1997). Today there are around 60 landfills in operation, down from 327 active in 1995, which had been closed as a direct result of inadequate environmental practise (Environment New Zealand, 2007).
Organic waste management in New Zealand also exhibits a spatial trend, with a wide range of practices and processes in place across the country. The most extensive and comprehensive system for capturing this resource is established in Christchurch, where council operated kerbside collection is widely available in the urban environment (Christison, 2013). Green waste is collected by many private companies and an increasing number of landfills are separating woody compostables and generating their own marketable compost. There is a National Compost Standard 4454 (Accredited product stewardship schemes in New Zealand, 2005) but the certification process has been a deterrent for expansion and extension into the commercial market. Further cities such as Nelson, Dunedin, and Auckand are expressing interest in dealing with organic waste whilst Invercargill and many smaller localities are consider organic waste as a utilisable resource, but lack the funding and infrastructural support to implement full scale public service operations (Devery, 2012).
Comparatively on the global state for organic waste resource utilisation, New Zealand ranks relatively well, placed 19th on a scale measuring the proportion of organics in landfill material. Germany exhibits best practice with only 14 percent going to landfill, whilst organics comprise 63 percent of waste generation in Turkey (OECD, 2007).
Public services vs private enterprises
"Only a small proportion of the organic waste produced in New Zealand is handled by territorial authorities" (State of the Environment, 2007)
Private landfills complete the market niche for waste disposal facilities and a considerable volume of organic and inorganic waste is deposited at these locations. These initially require local authority consent (Environment New Zealand, 2007 and Waste Management Institute of New Zealand, 2009) but in many cases there is little ongoing monitoring or regulation of these sites, and there remains a decided knowledge gap with a lack of publicly available data associated with privately run transfer stations.
From a service perspective many privately run companies also offer kerbside green waste collection amenities throughout the country; although as a user-pays operation there is often little incentive for the individual to actively practice waste separation. Kitchen waste is also excluded in many of these instances (Transpacific Waste Management, 2013), despite comprising a significant and steady proportion of household organic waste that would be greatly utilised if dealt with properly. A study carried out in the United States suggests that nearly 30 percent of edible food is thrown out each year, which are often highly compostable goods such as fresh fruit, vegetables and grain products (Kosseva, 2011). This amounts to about a $1 billion cost expenditure strictly attending to the waste of food. In the urban environment food waste may come from a range of sources including restaurants, businesses, and private homes that are often mixed with general everyday waste. New Zealand lacks any comprehensive analysis on the overall degree of food waste, however the United Kingdom estimates an average 6.7 milliton tons of household food alone is wasted annually (Kosseva, 2011).
Expanding Collection Options
"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" (MfE State of the Environment, 2007). This is encouraging, however potential exists to include kitchen waste in this stream.
As of the 2005 Ministry for the Environment publication "Options for Kerbside Collection of Household Organic Wastes", there have been four examples of councils running organic waste collection trials: Christchurch City Council, Mackenzie District Council, North Shore City Council, and Timaru District Council.
Follow up data for these initiatives has proven out of date, however Christchurch has since implemented a permanent city wide organic waste collection system in the Selwyn District (Options for Kerbside Collection for Household Organic Waste, MfE, 2005). A comprehensive overview of potential services developed by the Auckland City Council presented costing alternatives for city-wide organic waste collection. Estimates suggested separate green and kitchen waste collection would incur $26.9 million annually, whilst collection of green waste only ($12.7 million) or kitchen waste only ($13.7 million) prove to be substantially more economic options (Auckland Waste Management and Minimisation Plan, 2012). However this may not be the most effective option to adequately capture this resource and is highly dependent on the frequency and extent of service provision. Additionally by incorporating rural areas significantly increases expenditure, and the costing for monthly green waste collection amounts to the same as providing kitchen waste services on a weekly basis (Auckland Waste Management and Minimisation Plan, 2012).
Interestingly, to offer no service pertaining to organic waste, Auckland City Council suggest there is zero cost to the city, which does not reflect the actual cost to the environment and society. Environment New Zealand (2007) reported that illegal dumping, particularly of green waste, poses a health risk and amenity degradation and to mitigate related pressures on other services local authorities should address this issue.
Although organic waste is not specifically identified as an single component of the waste stream in the legislative framework, it is included as a waste substance, and therefore incorporated under the more generalised term ‘waste’. As is evident in the glossary “ Organic Waste; Includes garden waste, kitchen waste, food process waste, and sewage sludge” (The New Zealand Waste Strategy, 2010).
New Zealand Waste Strategy (2010)
Currently New Zealand’s overarching guidance for approaching waste is The New Zealand Waste Strategy (2010). This legislative framework was prepared by the Ministry for the Environment to set a series of targets to manage and minimise waste (The New Zealand Waste Strategy, 2010). This replaced the earlier 2002 strategy which hoped to drive New Zealand in a direction towards ‘zero waste’. In its place two distinct goals have been developed as a more realistic way for dealing with waste which are; to reduce harm effects, and improve the efficiency of resource use. Despite these goals pertaining a slightly more tangible task, they still lack any numerical targets to allow a clear comparison of future success with regard to the reduction of harm or progress towards improved efficiency of waste as a resource.
Within this strategy is an extended ‘tool kit’ of other forms of legislation that relate to and help manage and minimise New Zealand's waste loads and subsequent environmental effects. These include the Waste Minimisation Act 2008, the Resource Management Act 1991 (RMA), the Local Government Act 2002, along with the acknowledgement of the pressure and commitment New Zealand has on the international stage, such as the Stockholm Convention on Persistent Organic Pollutants (Ministry for the Environment, 2006) and the Kyoto Protocol 1997 (The Kyoto Protocol; MfE 2013).
Increasing population, particularly in urban areas, adds pressure to many of the local services provided in New Zealand (Environmental Indicators for Waste: Solid waste disposal; MfE, 2013). Likewise, economic growth allows for excessive consumption and production of waste where it is not extensively monitored.
Incentive-based policies and environmental taxes are widely employed around the world to help direct waste reduction behaviours (Kinnaman, 2013). New Zealand currently enforces an environmental tax whereby all remnant waste in landfill incurs a tax levy of $10 per tonne (Waste Minimisation Act, 2008). Clarke and Alibardi (2010) discuss penalisation for greenhouse gas emissions. As New Zealand waste contributes only 2.8 percent of New Zealand’s carbon dioxide emissions, it still supplies 2 million tonnes CO2 equivalent. This comparatively amounts to more than the carbon sink lost through deforestation (New Zealand's Greenhouse Gas Inventory, 2012). This is a further pressure for separation, diversion, and proper management of organic material decomposition and the Emissions Trading Scheme (ETS) reflects this.
Local governing authorities are required under the Waste Minimisation Act (2008) to follow the outlined principles, usually achieved through the initiation and implementation of their own regional and municipal waste plans and strategies. These attempt satisfy the requirements regarding waste reduction, waste disposal and the economic viability of any services provided. The effectiveness of this feed-down effect from central to local government reflects the pressure and urgency applied by both the attitudes of the individual citizen, and the governing administrators who acknowledge the potential for organic waste as a currently under-valued resource.
Case Studies: Management Methods
- There is no provision for organic waste collection by the Invercargill City Council and their local government legislation fails to satisfactorily address the pressures for action initiated by central government to minimise waste and merely acknowledges the benefits of reducing organic waste (Devery, 2012)
- The current state in the Southland area is that green waste/garden waste is available for chipping and reuse at transfer stations but there is no provision for composting and residents are expected to compost at home (Waste; Southland Resource Directory, 2007)
- The largely farming based community render it likely for households to have on-site composting facilities; however no comprehensive survey has been undertaken of this nature in order to gauge public response to waste minimisation ideas and there is very little information on waste management for the Southland area.
- Dunedin City Council's waste minimisation objective strongly acknowledges central government legislation pressures and goals
- Some initial responses by the council include:
- Sale of Bokashi Composting buckets
- Distribution of informational leaflets on home composting and worm farming
- Otago Farmer’s Market provides for food waste, paper, and cardboard to be disposed of at a local worm farm.
- Current state involves Dunedin Green Island transfer station including a recent green waste composting initiative (user-pays)
- Discounted disposal rates for customers bringing green waste suitable for composting
- Compost system does not accept kitchen waste
- (Dunedin City Council, 2013)
- Transpacific residential services provide user-pays garden waste wheelie bins in selected areas
- (Transpacific Waste Management, 2013)
- There is little incentive for residents to participate in home composting council initiatives
- Existing initiatives insufficient for urban setting where garden composting is impractical
- Pressure by central government legislation has been well considered
- Council has initiated multiple trials, first in 2002 and again in 2005
- 40 week long organic kerbside collection trial for 500 households in two suburbs in 2005 (Ministry for the Environment "Options for Kerbside Collection of Household Organic Wastes")
- Christchurch's current state is well advanced of most of New Zealand with its implementation of organic waste wheelie bin kerbside collection including both green waste and kitchen waste in 2009 following the previous trials
- (Christchurch City Council, 2013)
- Strong positive public response to 2005 trial with 94% household participation and 97% resident satisfaction (Moore, 2005)
- Best case study example of successful council-initiated organic waste collection in accordance with New Zealand’s overall waste minimisation targets
- strong reference point for other potential urban systems in New Zealand
- Nelson holds organic waste as "high on the list of priorities" as a result of legislative pressure.
- Potential for investment into organic kerbside collection indicated by Nelson City Council.
- Response through providing a Green Transfer Station, no kitchen waste facilities.
- Current state shows council encourages public to separate and divert organic waste from landfill through a $15 subsidy for residents to purchase a compost bin, warm bin or bokashi bucket.
- (Nelson City Council/ Tasman District Council 2008).
- Current state of Wellington composting emphasises education and relies on private compost operations
- Wellington's response to consumer pressure is the Kai to compost (user-pays) scheme which collects food waste from restaurants and businesses which is mixed with green waste and composted at Living Earth plant at the Southern Landfill.
- Privately owned system but promoted by the council in place of a council run system.
- Does not service residential
- (Wellington City Council, 2013)
- As New Zealand's capital, Wellington has additional pressure to be at the forefront of national legislative efforts
- The current state in Auckland is that there is no current council kerbside organic waste collection system.
- Multiple private services available currently
- The Auckland City Council has a detailed kerbside organic waste collection plan section in their 2012 Waste Management and Minimisation Plan to be implemented in 2015 in response to high public demand.
- Plan recognises that 50% by weight of Auckland's waste sent to landfill is organic.
- Plan takes into account pressure for minimisation of effect on existing private green waste collection industry.
- (Auckland City Council, 2012)
The shortfalls in current information as to the state of the environment for organic waste have been identified and addressed above. There are many potential indicators and services that could be implemented to satisfy the goals of the New Zealand Waste Management Strategy (2010) and Waste Minimisation Act (2008) in a response to pressure from a range of sources. In some cases local communities have already developed indicators relating to waste management and minimisation which have the potential to be developed and employed on a regional or national scale.
- Survey of proportion of households with compost bins
- New Zealand Waste Strategy Reports to include waste category sub-sections (i.e. organic, cleanfill, recycling centres)
- Measurements and standards implemented for leachate; more widely used
- Development of processes to capture gaseous by-products; utilisation of this as a resource and potential increase in participating facilities and energy production
- Consider current and innovative minimisation methods as an indicator of diverted waste
- Reduce the margin of error associated with current methods for estimating waste composition and quantity data, refine these techniques
Services as a response
- Kerbside organic waste collection akin to current glass, paper and plastic recycling systems
- Education classes for effective composting
- Regulation more strict on privately owned landfills
- Council-initiated construction of household or neighbourhood compost bins
The OECD (2008) recommend that management options should have a more active role and provide greater supervision in the use of resources (OECD Environment Directorate, 2008). A number of trial studies have been undertaken to explore the viability and effectiveness of providing kerbside organic waste collection. A general shift in the way people interpret organics as 'waste' instead of 'resource' is necessary to transform norm behaviours and attitudes, into utilising their green and kitchen organic items. The assessment and information pertaining to these studies is not easily obtained and additional trials at a wider range of locations should be explored.
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