THE old adage that you should never let the facts get in the way of a good story was obviously in Francis Cheung King-fung's mind when he penned his article entitled 'Scheme that stinks' (Sunday Morning Post, December 18).
Although the group calls itself the Study Group for Infrastructure Development, it has obviously not studied the Strategic Sewage Disposal Scheme (SSDS) properly to ensure the basic facts are correct; its analysis as such is misleading and does not help readers understand the real issues.
It would also appear the group has no basic knowledge of sewage treatment processes as it dismisses chemically-enhanced primary treatment as being unable to reduce toxic metals and organic compounds to an acceptable safety level, when the process can actually remove up to 70 per cent of toxic metals and 78 per cent of organic pollutants in the waste water.
The group is obviously unaware of the advances in sewage treatment technology which have been achieved in Scandinavia and the United States by resorting to Chemically Enhanced Primary Treatment (CEPT). Research conducted by the US Government's National Research Council shows there is in fact very little difference in the effluent quality produced by the CEPT process as compared with biological treatment. The former is, however, much more environmentally friendly as biological treatment uses 2.5 times as much energy, costs twice as much to build and operate, and produces 20 per cent more sludge which must be disposed of in landfills.
So successful is the CEPT that the US Government has recently changed the federal law covering sewage disposal to allow coastal cities to discharge primary treated effluent into the marine environment. San Diego in California has used this process successfully and, after many years of monitoring, demonstrated that it produces no harmful effects to the marine environment.
This change in US policy is extremely significant as for over 20 years all cities in the US have been required to provide secondary (biological) treatment for their waste water, regardless of location. The San Diego experience has shown that a uniform, technology-based solution to waste water disposal is not the correct way to deal with the problem and that an environmental water quality approach is the better method. This means, in effect, that an appropriate treatment process should be chosen to achieve specific water quality objectives, which is the way in which the problem is being addressed in Hong Kong.