HONGKONG'S $23.8 billion sewage strategy has come under attack from a former member of a government-appointed environment committee, who claims it will be harmful and leave the post-1997 administration with a heavy clean-up burden. Dr Wan Shek-luen, who was also invited by the Chinese side of the Joint Liaison Group last August to comment on the impact of major infrastructure projects, said plans to pump Hongkong's sewage into the South China Sea were unsound. The sewage would receive only partial treatment to remove toxic metals and bacteria, and would still contain organic material that could cause long-term pollution problems, he said. The Government plans to build a treatment plant at Stonecutters Island then pump the sewage via a 35-kilometre pipeline into the sea, where it is expected that ocean currents will break it up and disperse it. But it has committed money only to the treatment plant and a new sewer network to collect the waste, and is leaving funding of up to $10 billion for the pipeline to the Special Administrative Region government. Until the tunnel is built, the harbour willstill be at risk of pollution problems, said Dr Wan. He recommended setting up smaller treatment plants around Victoria Harbour with a high level of treatment to remove all harmful material, rather than pump it out to sea. He said his company could set up the plants, which could be privately-run and include space for private developers. The Environmental Protection Department, whose officer in charge of the scheme yesterday declined to comment, had earlier rejected this option because it would take up too much land - each plant would need an area greater than the Convention Centre - andwould be more costly. But Dr Wan said: ''I think the Government is misleading the public by proposing a scheme which could incur long-term environmental liabilities. It's morally incorrect dumping sewage outside Hongkong territory.'' Dr Wan was an appointed member of the Environmental Pollution Advisory Committee for several years until 1989, when he resigned in part because of his dissatisfaction with the sewage strategy. ''I would say in my two decades of experience and involvement with the environment in Hongkong, this [the sewage strategy] is the single major environmental disaster which the colonial government has made,'' Dr Wan said. Meanwhile, proposals to charge householders and industry for sewage disposal will not be released this month as earlier promised. The Principal Assistant Secretary for Planning, Environment and Lands, Ms Chang King-yiu, said the charges were still being finalised.