Summary of Presentations

Utilisation of Organic Waste For Sustainable Energy Production
(OWSEP)
Workshop held at Maidenhead Town Hall: 11th December 2002

This green waste event attracted considerable interest from some 35 local authority officers, councilors and waste industry workers. Councilor Hugh Wilson chaired the meeting for the day and emphasised from the start the need to come up with practical solutions that could be adopted in the Thames Valley. The event was organised by TV Energy through the OWSEP project funded by the shanks first fund, the aim of which is to investigate the utilisation of organic (green) waste for energy production with a view to establishing one or more flagship hybrid facilities in the Thames Valley.

The first phase of the work carried out this year (of a three year programme) by TV Energy reviewed appropriate technologies and available resources and concluded that key target areas for continued investigation are the use of anaerobic digestion techniques for putrescible waste (where the moisture content is > 50%) and biomass conversion technologies for essentially clean wood waste brought to civic amenity (CA) sites. This workshop focused most attention on the technology option offered by anaerobic digestion and included a range of speakers with very differing experiences with waste collections, processing and legislation.

To start off the day Keith Richards and Charlotte Bruton PDF(1.7MB) gave an introduction to TV Energy and their aims regarding the utilisation of organic wastes for energy production and their progress within the OWSEP project to date.

Michael Chesshire PDF(125KB) of Greenfinch Ltd then gave a presentation about his experiences with anaerobic digestion and collections of putrescible wastes from households in Shropshire. Michael's trials have gained him much knowledge in the field of digestion of biodegradable municipal solid waste (MSW) and he was able to clearly describe the benefits of source separated waste for example, the dry recyclables are uncontaminated making them easier to recycle, vermin and smell problems are contained and the fertiliser produced is uncontaminated. In addition, Michael demonstrated some of the benefits of utilising a system such as anaerobic digestion; recycles high moisture biodegradable waste, it is in-vessel and odour free, it recycles nutrients and produces energy amongst other benefits.

Sally Wright PDF(236KB) from Wycombe District Council then spoke about the 'Bio-Back Trial' that had been in operation since 1994, a trial that has included aspects of community consultation and education. The trial is definitely an example of best practice in the Thames Valley and able to link to future activities. The presentation showed that householder support for 'kerbside collection' is difficult to achieve but nevertheless can be achieved given the will and continued support through regular communication.

Henrik Ørtenblad PDF(122KB) then gave a presentation about the current state of development of biodegradable waste management in Denmark. He offered a rather enlightening view about waste processing and demonstrated that in Denmark wastes are considered holistically, so that farm / agricultural waste, commercial / industrial wastes and organic waste from MSW are treated together using anaerobic digester technology. This holistic approach has worked extremely well for the Danes and has put them in the forefront of waste technology and strategy in Europe.

The final presentation for the morning came from Samantha Isaac PDF(395KB) from Entec Ltd, an environmental and engineering consultancy that also helps local authorities in the Thames Valley region produce waste strategies. Sam focused her talk on the impacts of the European and national legislation on the development of waste strategies. She spoke about the Landfill Directive and the need to divert biodegradable waste from landfill, the statutory targets for local authorities with regards to the increased quantities of waste to be recycled and in particular, the animal by-products order which will affect the composting and digestion of catering waste that includes domestic kitchen waste. The key message here was the need for Local Authorities in particular to change and to change rapidly in order to be able to comply with future requirements and legislation.

Sam also highlighted the fact that currently the definitions of anaerobic digestion (AD) within Waste Strategy 2000 does not conform to the perception of AD within the industry or technologists. (Aerobic) Composting is classed as recycling thereby counting towards the Local Authority 'recycling' targets, however, anaerobic digestion (or anaerobic composting) is classed as 'recovery' and counts towards the landfill diversion targets but not the statutory recycling targets. This complex situation may be changing for the better as a result of as much lobbying from within the industry and it is expected that within the next batch of amendments to the Waste Strategy, anaerobic digestion will be classed as 'recycling'.

The afternoon session commenced with an interesting presentation from Chris Hatton PDF(865KB) of Thames Waste Management (TWM). Chris talked about the work carried out by TWM at Thames Water sites using a variety of materials to co-digest with sewage sludge. One particular trial used MSW from High Wycombe from which the biodegradable element was separated using a DANO drum. This component then went through further separation at the sewage treatment plant to remove small fragments of glass and stone. It was then co-digested to produce biogas used for energy production and a fertiliser used on agricultural land. The trials conducted were very successful and Chris enthusiastically expressed his confidence in the technology.

The series of presentations was then followed by a debate in which all delegates were invited to join. For a summary of the workshop discussion please click here.