Waste Management for Low Carbon Cities Improving Waste Management and Recycling
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Waste Management for Low Carbon Cities Improving Waste Management and Recycling Contributors: June E Lombard Rosemary K Lombard Icando Environmental Management & Training CHAPTER CONTENTS 1. Waste’s contribution to greenhouse gas emissions ..................................................... 2 2. Current initiatives in eThekwini Municipality that reduce carbon emissions .............. 2 2.1 Materials recovery for recycling ............................................................................. 2 2.1.1 Separation at source with kerbside collection ...................................................... 3 2.1.2 Materials Recovery Facilities ............................................................................... 3 2.2 Composting .............................................................................................................. 8 2.3 Energy recovery in eThekwini Municipality ........................................................... 9 2.3.1 Landfill gas to electricity projects in eThekwini .................................................... 9 2.3.2 Waste water to energy projects ......................................................................... 13 2.3.3 Additional carbon reduction projects in planning stages in eThekwini Metro ...... 14 3. Further opportunities to reduce GHG emissions in the waste sector ....................... 16 3.1 Waste avoidance and recycling ............................................................................ 16 3.2 Mechanical Biological Treatment incorporating Waste to Energy ..................... 17 3.2.1 Mechanical treatment as part of MBT ................................................................ 17 3.2.2 Biological treatment as part of MBT ................................................................... 18 3.3 Carbon sequestration – CO2 fertiliser .................................................................. 23 3.4 Biofuels and industrial processes ........................................................................ 24 3.5 Composting ............................................................................................................ 24 4. Overcoming barriers to implementing waste management strategies ...................... 27 4.1 Waste to electricity options ................................................................................... 27 4.2 Public Private Partnerships ................................................................................... 28 4.3 Recycling constraints ............................................................................................ 28 4.4 Incineration options ............................................................................................... 29 5. Financing opportunities for waste projects ................................................................. 29 5.1 CDM ........................................................................................................................ 29 5.1 Other opportunities ............................................................................................... 33 6. Recommendations......................................................................................................... 33 Waste avoidance and recycling ........................................................................................ 34 Mechanical Biological Treatment incorporating Waste to Energy ................................. 34 Carbon sequestration – CO2 fertiliser .............................................................................. 35 Biofuels and industrial processes.................................................................................... 35 Composting ....................................................................................................................... 35 Waste-to-energy systems ................................................................................................. 35 7. USEFUL WEB SITES ...................................................................................................... 36 8. BIBLIOGRAPHY ............................................................................................................. 36 1 ‘The convenient truth about waste management is that the waste industry could act as role model and make partnerships with cities and other industries in a global and result- oriented action for significant GHG emission reduction..’ Jens Aage Hansen.’ 1. Waste’s contribution to greenhouse gas emissions South Africa recognises waste and associated polluting gases as significant sources of greenhouse gas emissions, particularly in urban areas. Methane and carbon dioxide from the anaerobic biodegradation of organic wastes in landfills, which are still the main method of disposal in the country, as well as the emissions of nitrous oxide, N2O, from combustion processes are the most significant of these. Worldwide it is estimated that waste management activities, especially the disposal of waste to landfill and concomitant generation of methane, contribute to global greenhouse gas (GHG) emissions by approximately 4 %1. There is a growing body of evidence based not only on Life Cycle Assessment2 but also on real-life studies3 that local government can lead integrated waste management activities and make a significant difference in terms of GHG reduction, changing what initially is a per capita net positive GHG emissions to a net GHG negative emissions situation (by replacing fossil fuel generated electricity with renewable energy, avoiding manufacturing energy consumption for virgin materials, and reducing methane emissions from landfills). The reduction of greenhouse gases has become an important driver for managing waste differently from past practices. Cleaner production, recycling and more energy efficient waste management technologies with less potential to generate greenhouse gases are being actively promoted, not only by South Africa’s recent waste-related legislation, but also by the economic incentives offered. eThekwini Metro Municipality is one of the leading municipalities in the country in this regard. This chapter examines the initiatives currently underway in the Metro as well as those still being planned. It also considers other opportunities and constraints to improving waste management and recycling, in the drive to reduce eThekwini’s carbon footprint even further. Reduction of GHG emissions in the waste sector can be achieved in a variety of ways: • Recovering materials for recycling into new products, thus avoiding the energy-consuming beneficiation and primary manufacturing processes that is otherwise necessary in the use of virgin materials. • Reducing emissions of landfill gas (an approximately 50:50 mixture of methane (CH4) and carbon dioxide (CO2) by better landfill practice and by reducing the organic wastes entering the site. • Utilising and/flaring off landfill gas for both heat and electricity generation. • Reducing methane emissions from wet anaerobic processes e.g. sludges. • Recovering energy and reducing carbon emissions from waste using Mechanical Biological Treatment processes. • Utilising the carbon dioxide from combined heat and power plants as a carbon dioxide fertiliser in greenhouses. 2. Current initiatives in eThekwini Municipality that reduce carbon emissions 2.1 Materials recovery for recycling To maximise the recycling potential of materials, sorting recyclable materials from non-recyclables at source to recover relatively clean, and therefore higher value, materials is essential. 1 Bogner et al. (2007) 2 Waste Management and Research, Vol 27, Issue 9, Nov 2009. Special issue: Applied Green House Gas Accounting: methodologies and cases. ISWA ISSN 0734-242X. http://wmr.sagepub.com 3 Hansen, J.A. (2009) Editorial. Waste Management and Research, Vol 27, Issue 9, p 837-838. 2 The eThekwini Metro Waste Management Agency, Durban Solid Waste (DSW), has promoted a variety of alternative options for recovering materials that would otherwise end up on a landfill. The most desirable option is to recover discarded materials as close to their source as possible, before they become contaminated by other wastes and reduced in value. Kerbside collection, drop-off and/or buy- back centres for recyclable materials all achieve this objective of separation at source. If mixed wastes are received, the recyclable materials have to be sorted from the waste stream at what is often referred to as a ‘dirty MRF’ i.e. a Materials Recovery Facility where recyclables contaminated by other waste are recovered. Theoretically, reference is sometimes made to a ‘clean MRF’, where separated but ‘co- mingled’ recyclables are further sorted into their respective categories, but it is questionable whether such a facility exists in reality, given that there is generally a relatively high level of soiling of materials due to unwashed containers in any stream of co-mingled recyclables . 2.1.1 Separation at source with kerbside collection The Mondi Recycling Company’s4 orange bag collection system in eThekwini Metro has been successfully implemented in approximately 800 000 households. Mondi supplies the orange plastic bags to households (1 per household per week) for mixed paper and plastic, while DSW supplies the black bags for residual waste to houses on a quarterly basis (2 per household per week). Mondi contracts their agents to pick up the orange bags on the same day as the municipal kerbside collection of black bags takes place. The materials are transported to the Mondi Recycling Company’s