ENG-1980 — Page 289

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THE ENVIRONMENT

Floating refuse continued to be a problem and, during the year, 4,339 tonnes of floating refuse was collected from the harbour - including that retrieved by the free service which collects domestic refuse from ocean-going vessels.

Following extensive trials with two mechanised, floating refuse collectors, plans are now well advanced to mechanise the entire system over a five-year period. Initially, the new craft will cover only the present areas of collection, which extend from Tsuen Wan in the west, through Victoria Harbour to Junk Bay and Chai Wan in the east, and also to Aberdeen Harbour. However, in view of the rate of industrial and urban development in Hong Kong, plans are in hand to provide harbour cleansing services at Cheung Chau, Tuen Mun, and later at Sha Tin. Phased mechanisation of the present manual methods of collection will in future provide a more efficient service with higher cost effectiveness.

The effects of water pollution on the stocks and quality of fish and shellfish around Hong Kong are investigated by the Marine Pollution Research Unit of the Agriculture and Fisheries Department. The work of the section has included investigation of toxic metal levels in shellfish, basic surveys of sea-bottom life, and the possibility of discharged nutrients producing unpleasant algal blooms and consequently killing fish. Although very large catches of commercial fish are not taken from adjacent waters, Hong Kong does have an important fish-rearing industry based on floating cages. Marine fish culture is considered capable of expansion if water quality can be maintained.

There is considerable water pollution in some of Hong Kong's low-lying areas where streams and rivers cross agricultural land, often through nullahs in villages and towns, to enter the sea. In addition to large quantities of domestic waste, the streams receive agricul- tural waste emanating from the half-a-million pigs and six million chickens in the New Territories. Pilot schemes to collect or divert these wastes are in operation. However, the scale and complexity of the problem is such that it may prove economically feasible to deal only with selected areas in the near future.

Waste Disposal

The enactment of the Waste Disposal Ordinance in 1980 provided statutory powers over waste collection and disposal to the Director of Public Works, the Director of Agriculture and Fisheries, the Director of Urban Services (and his authority in the New Territories, the Director of New Territories Services).

Of the 2,010,600 tonnes of waste generated in the territory this year, by far the greatest amount – 1,130,000 tonnes - was disposed of at controlled tips. There are limits on extending this method of disposal, however, due to the competing demands for land use in Hong Kong. As a means of greatly helping to reduce this problem, consideration is now being given to the use of controlled tipping to create development land.

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Incineration, which accounted for 809,000 tonnes of waste disposal over the year, is considered less desirable than controlled tipping because of higher costs and the associated problems of air pollution. Two recently-built waste treatment processes the composting plant at Chai Wan and the high-density baling plant as Sai Tso Wan - processed approxi mately 64,000 tonnes of waste between them. The processed waste was disposed of primarily at controlled tips.

In 1979, the New Territories Services Department initiated a pilot scheme at Ta Kwu Ling for the collection and transportation of agricultural waste to a controlled tip. This scheme achieved some success by early 1980 and it has now been extended to the Hung Shui Kiu area where river and stream pollution from agricultural waste is particularly acute.