Measuring black carbon emissions from open burning of waste

Black carbon (BC) emissions from the open burning of municipal solid wastes (MSW) and other waste types contribute significantly to global heating but are not yet included in the official (IPCC) inventory of greenhouse gases (GHGs) due to poor data availability. Natalia Reyna has just completed her PhD thesis at Imperial College London, co-supervised by Professors David C Wilson and Stephen R. Smith, with the aim of generating reliable data to plug that gap. Our second and final paper was published last week in the leading journal Atmospheric Environment, providing a reliable methodology for measuring emission factors (EFs) for black carbon from waste burning. i.e. how much black carbon is produced by burning a kilogram of waste. The two papers have been submitted as evidence to the IPCC sixth assessment study due to be published in 2021.

When the measured emission factors are combined with our earlier measurements of the extent of open burning of municipal solid wastes in Mexico; other published estimates of waste composition and activity levels around the world; and a range of estimates of the global warming potential of black carbon as compared to CO₂; our best estimate of the contribution of BC from the open burning of MSW to global heating is in the range 2-10% of global CO₂Eq emissions. Given the associated air pollution and health impacts, urgent global action is essential to eliminate open burning of waste; this will provide a relatively ‘quick win’ in tackling the global climate emergency.
A short article reporting this research appeared in the September/October 2019 issue of CIWM’s new, award-winning magazine Circular.

Tackling the global waste crisis through community waste management

According to the UNEP and ISWA’s Global Waste Management Outlook (GWMO), three billion people lack access to basic solid waste management (SWM) services; addressing this global waste crisis would not only vastly improve their lives but also halve the weight of plastics entering the oceans. Professor David C Wilson and Mike Webster of Wasteaid made the case earlier this year, in an open access editorial in the ISWA journal Waste Management & Research, for community waste management as a ‘bottom up’ approach, to run in parallel to traditional ‘top-down’ approaches led by donors and governments.

Community waste management aims to help local communities in the poorest countries, where the local authority often has no funds to provide a SWM service, to tackle the problem themselves through the resource value in the wastes. If, for example, food wastes or low-value plastics are kept separate, they can be turned into new, useful products. With simple tools and the right knowledge, people can become self-employed recycling entrepreneurs, providing a very valuable service for the health and wellbeing of their community, and the whole planet – as well as reducing poverty and creating sustainable livelihoods.

One of the gaps identified by the GWMO was for practical guidance on such low-cost ‘waste to wealth’ technologies which involve minimal capital investment and make products to sell in a local market. DCW’s CIWM Presidential Report aimed to plug that gap: Wasteaid prepared a Toolkit, including a dozen How-to-do-it Guides for simple technologies using organics and low-value plastics.

While preparing the Toolkit, we identified a parallel requirement, for the scientific underpinning of some of the technologies. This month sees the publication of a paper on optimising the technology for producing plastic bonded sand blocks, for use e.g. as paving slabs, from the low value LDPE film plastic, which is a major problem even in the least-developed countries. Our team at Imperial College London was led by Professor Chris Cheeseman, with the laboratory research carried out by Alexander Kumi-Larbi Jnr and Danladi Yunana. The technology was developed by another co-authors, Pierre Kamsouloum, a self-taught entrepreneur from the Cameroun.

Don’t waste our climate

In his July column, CIWM President David C Wilson makes the case for more investment in resource and waste management as an ‘entry point’ to achieve significant climate mitigation. The sector already has a track record in developed countries, with methane mitigation from landfill since the 1970s, and both methane mitigation and recycling making a major contribution to meeting Kyoto Convention greenhouse gas (GHG) reduction targets between 1990 and 2010. But that early success also means that the IPCC’s 2010 assessment is that the ‘waste’ sector only contributes 3-5% to current GHG emissions. DCW argues that this is a gross underestimate which fails to consider: the current emissions from uncontrolled burning; historical reductions; contributions across the economy from recycling; and waste prevention (particularly food waste).  The results suggest that better resource and waste management has the potential for reducing GHG emissions across the World economy by 15, 20 or 25% or even more. Such numbers may be guesstimates, but whatever number we choose to use, the message is still the same. Further investment in this sector, in both developing and developed countries, is a major political priority in order to meet our climate targets.

This article was subsequently re-published by the National Solid Waste  Association of India (NSWAI) in their member journal Waste Monitor in July 2019.

Uncontrolled burning of solid waste as a significant contributor to climate change

To qualify for inclusion in the official (IPCC) inventory of greenhouse gases (GHGs), data for an emission source must meet a quality threshold. This currently excludes black carbon emissions from the open burning of wastes. The relative quantities may be small compared to carbon dioxide from fossil fuels or methane from landfill, but black carbon is around 2,000 more powerful than CO₂ as a GHG and has an even shorter half-life than methane. In the absence of real data, early modelling studies using broad assumptions suggested that black carbon from open burning contributes 5% of total global GHG emissions, causing 270,000 premature deaths a year. DCW’s PhD student at Imperial College London, Natalia Reyna, has been working for the last four years to provide real data which would meet the IPCC requirements. Our first paper, published this month in the leading journal Environmental Research, presents field data from Mexico on how much solid wastes are disposed of by open burning, either by households or at uncontrolled dumpsites. The results suggest a GHG contribution from uncontrolled burning in backyards in Mexico fifteen times larger compared to methane released from the decomposition of equivalent amounts of waste in a disposal site. This suggests that urgent action is needed to reduce domestic open burning of waste and that this would have a significant impact, both on improving local air quality and respiratory health, and on reducing climate change. A future paper will present data on emission factors, i.e. how much black carbon is produced by burning a kilogram of waste.

New tool to strengthen the informal recycling sector

The informal recycling sector makes an important and often undervalued contribution to solid waste management in many developing countries. They sit at the base of what is often now a global supply chain for recycled materials, and like other primary producers could benefit from initiatives to add value to the materials they collect. Professor David C Wilson’s team at Imperial College London have just published a new tool, based on Value Chain Analysis (VCA) as developed to improve the livelihood of poor farmers in Africa, using the iconic Zabaleen recyclers in Cairo as the demonstration case. VCA provides a significant and powerful addition to the analytical tools available for improving the position of the informal recycling sector. The paper, published in the peer-reviewed journal Resources, Conservation and Recycling, can be downloaded free-of-charge until 17 September 2016.

The informal recycling sector can achieve recycling rates of 20-40%, significantly reducing the burden falling on the city for managing the remaining solid waste. However, there are serious issues of poor working conditions, child labour and uncontrolled dumping of residual wastes. Considerable efforts have been put into integrating the informal recyclers into a city’s formal solid waste management system, to everyone’s benefit: the recyclers can work under cleaner conditions, earn a better livelihood and educate their children; recycling rates can potentially increase; and the transition can facilitate environmental control, as well as bringing the ‘informal’ sector inside the legal and tax systems. DCW has been actively researching this area for more than 10 years; his 2006 review has more than 180 citations, while a 2012 paper developed the InteRa framework and tool for use in designing interventions for informal sector integration. He first researched the potential for adapting Value Chain Analysis (VCA) for use in this sector in 2009 with Dr Sanjay Gupta in India, and was delighted to have the opportunity in summer 2015 to carry out fieldwork with the GIZ National Solid Waste Management Programme project team in Egypt on this paper. The lead author is Remi Jaligot, then a Masters student at Imperial College London, and the other co-authors are Prof Chris Cheeseman of Imperial and Berti Shaker and Joachim Stretz of GIZ Egypt.