Engineer says burn Chch rubbish, create power

Press, 20 July 1987, Page 9

Engineer says burn Chch rubbish, create power

A giant incinerator disposing of Christchurch’s rubbish would also produce about 10 per cent of the city’s electricity needs as well as being more efficent than the city’s refuse system, asserts a chemical engineer. Mr Charles Martin, an engineer and a member of the Canterbury United Council’s technical advisory committee, advocated the construction of a giant furnace, similar to ones used in the United States, Europe, and Australia. “It would cost about the

same as the present refuse system and would provide about 10 per cent of the city’s electricity, too,” he told "The Press.” The idea was rubbished, however, by the City Council's engineer, Mr John Ince. The idea of a furnace was investigated in the mid 1970 s when City Council and Waimairi District Council engineers toured overseas seeking ideas on refuse disposal. Mr Ince said Messrs Bruce Forbes (City Council) and John Lamb

(Waimairi) discovered “all sorts of problems with furnaces.”

“Plus, at present we have a system that cost several million dollars and there is no evidence to point to furnaces being any more efficient.” Mr Martin said that based on the annual tonnage of rubbish from Christchurch households and industry — 197,000 tonnes — about 10 per cent of the city’s electricity could be generated using a furnace.

“It would not create a pollution problem as rubbish has a low sulphur content so there is not much smoke. The rubbish would have a gross specific energy content of 11.6 megajoules a kilogram. Although it would not bum as efficiently as coal it would still be able to produce about 131 gigawatt hours of electricity a year. “Christchurch uses about 10 times that each year — so, there is 10 per cent of its needs generated from its rubbish.” “It is definitely going to happen here, sometime,” he said. The furnace would burn rubbish down to a hard, rubble-type substance which could be used for reading material. The rubbish would burn down to 5 per cent of its original weight and about 2 per cent of its original bulk. Such disposal was more

desirable than the present landfill method, said Mr Martin. “That is ruining the sandhills in the north of the city which will one day be residential. It also produces an effluent — rotting landfills give off a nasty effluent,” he said. Mr Ince denied this. The Canterbury region was dry and the effluent, if there was any, would be soaked up. He dismissed also Mr Martin’s assertion that the city was running out of landfill area. “As far as I am aware the city’s landfill resources will last another 20 years and there are other areas aside for when they do run out,” he said. Mr Martin said a furnace would cost no more than the present system. He had been involved with a furnace in Australia. “It is running well now, although there were some problems in the beginning.” If a furnace was developed it would require only low technology because the bulk of Christchurch’s refuse was small compared with other cities using the method. Mr Ince said the Auckland Regional Authority had investigated the idea, too, and had declared it unsatisfactory and uneconomic. He saw no way that Christchurch would develop one.