The 2009 SCI Plant of the Year Award was won by VEOLIA Environmental Services for its Woodlawn Bioreactor. The bioreactor converts Sydney’s putrescible waste into electricity at the former Woodlawn open-cut copper mine site near Tarago, some 250km south-west of Sydney, Australia. In 2008 it consumed 400,000 tonnes of waste. The waste is compacted, containerised and transported by rail from Sydney to a purpose-built transfer station near Tarago from where containers are taken by road to the Woodlawn site.
The bioreactor is believed to be the largest of its type in the world. It is a conical void, 800 metres in diameter and over 200 metres deep, with a capacity of some 25 million cubic metres. At the current rate of filling, it could take over 50 years before it reaches capacity, although VEOLIA plans to increase the rate of waste accumulation in years to come.
The waste is spread at the bottom of the open cut mine, and leachate is recirculated through the deposit in order to provide optimum moisture content for anaerobic bacteria present in the waste, to convert carbonaceous material to methane gas. The methane is collected in an elaborate system of plastic and steel pipes and pumped to a series of G E Jenbacher generators (specialised reciprocating engines designed to work on a mixture of methane and air). The electrical energy generated, is sold into the State electricity grid. Currently VEOLIA has a contract to supply 1,350 Gigawatt hours of 'green' electrical energy. There is provision to add more generators as methane production increases. Future developments include recovery of waste heat from the engines to establish an aquaculture facility.
Hydrogen sulphide is controlled by the addition of metal oxide to the waste as an in-situ chemical scrubbing system. The project (costing over £40m) meets all the criteria for a ‘Plant of the Year’ award. The major benefit to the environment is capturing methane and converting it to electricity, thus substantially reducing greenhouse gas emissions. Members of the SCI Australia International Group, including Professor John White, Mr Jon Morey, Mr John Fowler (Hon. Secretary and Treasurer) and Dr Richard Thwaites (Hon Chairman) visited the Woodlawn site on Monday 31 August 2009 to congratulate the company on its achievement and to present a plaque and citation to Mr Doug Dean (CEO of VEOLIA Environmental Services). The Woodlawn Bioreactor has already received numerous Australian awards for its use of ground-breaking cutting edge technology in waste disposal management and utilisation.
- The picture shows a general view of the bioreactor, approx. 200 metres deep and 800 metres in diameter. Note the roadway leading down to the bottom of the facility and the 40 foot container being unloaded at the base
John Fowler and Richard Thwaites