Howard Robinson, Keith Knox and Bob Gregory reported from Sardinia 2015, the 15th International Waste Management and Landfill Symposium, in the CIWM journal a few months back. This is a precis of that article.
The biennial Sardinia Symposium, organised by the International Waste Working Group, attracted 732 delegates from 66 countries in October 2015. There were over 530 scientific papers in 128 technical sessions and workshops. 36 out of 112 English language sessions were on landfill, the largest single topic. Next was characterisation, recycling and waste minimisation, with 26 sessions.
Opening plenary lectures by retiring German professors Werner Bidlingmaier and Bernd Bilitewski, gave insight on changes in the waste industry, and its future. They noted that although we are far better at recycling wastes, we are failing to avoid waste production. The Special Guest Country at this year’s Symposium was China. Chinese municipal solid waste (MSW) has a very high food content by Western standards (50-75%) and consequently a moisture content from 50-60%. This creates special problems for both landfilling and incineration of MSW.
Landfill gas recovery continues to hold a high interest internationally. For actively gassing landfills there were suggested improvements in gas well design and gas recovery, treatment of landfill gas to increase methane content, and removal of hydrogen sulphide and carbon monoxide, again to improve usability of the gas. For both operational and closed/late life landfills, methane surface emissions management techniques were examined in detail. Several UK reports showcased the recent work of Defra and the UK Environment Agency to understand LFG emissions better, and indeed, a paper by NPL and the EA on regulating landfills using measured methane emissions won the John Pacey prize for best landfill gas paper. Tracer techniques described at the Conference are also practicable ways of examining methane emissions, and are possibly more suitable as a routine technique. The EA’s ACUMEN project showcased technologies for recovering low quality landfill gas for small scale power and heat generation, and also for low calorific value gas management.
My presentation urged developers to consider the re-use of existing grid connections for longer term power generation capability, such as solar PV, while using a low calorific value flare for declining gas management. Others favoured accelerated landfill stabilisation using firstly leachate recycling and secondly in-situ aeration, followed by landfill mining, although the economics and practicalities remain challenging, and could only be seen as part of wider environmental rehabilitation. It is notable that local legislation and renewable energy enabling mechanisms remain the two most significant drivers for landfill gas utilisation and management, in both developed and developing countries.
In addition to landfill gas management papers, UK delegates presented several state-of-the-art case studies into leachate treatment and management. In contrast, of more than 50 presentations on incineration or ash management, only one had a UK author. Similarly, only one paper out of 37 on Anaerobic Digestion was written by a UK delegate.
The conference closed with a round-table discussion on Waste Management in Mediterranean Countries, specifically looking at cities such as Naples, and the highly topical subject of waste management in refugee camps, and on islands.