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Limited enquiries from importers of sanitary and electric appliances have not yet been able to establish whether these units are on sale in Hong Kong, and it has not been possible, therefore, to estimate the total cost of an appliance and its installation; (b) additional demand for water is created by the use of these units. In the United States of America where they were first introduced, this has been estimated to be in the region of one gallon extra per person per day;
(c) if the disposal units were installed in large numbers, they could have an effect on the sewage systems, as there would be a great increase both in the amounts of water flowing through the sewers and of solids present in the content;
(d) most of the sewage in Hong Kong is discharged into the sea, especially the harbour, for disposal. If mechanical water-borne waste disposal units were brought into general use without the sewage and garbage being subject to primary treatment, increased pollution of the harbour and beaches would probably result as, unlike human waste and toilet paper which is soluble, much of the domestic garbage, for example potato peelings and food waste, is not readily soluble and would take a much longer time to decompose. The resultant effluent from these units, therefore, could contribute to an increase in water pollution, especially visual pollution.
From the Departmental point of view, the mechanical garbage disposal units in kitchens are hygienic (since there would be much less offensive matter deposited into household dust-bins) and they would reduce the bulk of refuse required to be handled by our staff; but at the same time the amount of sewage to be moved from the primary sewage treatment plants in the form of liquid sludge would inevitably be increased and would present additional problems in the further treatment and disposal of the sludge.
As Members will no doubt be aware, restaurant and eating-house food waste finds a ready sale to pig-breeders. As this forms the bulk of the garbage which could be disposed of by mechanical disposal units there would appear to be little point in requiring licensed restaurants to install these units as a condition of licensing.
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Finally, in response to the last part of the question, the Department has consulted the Director of Engineering Development for his initial comments, which are that in late 1971 a study on the feasibility on local usage of these disposal units was carried out. This concludes that:-
(i) if the whole community were to use these units the pollution strength or degree of the sewage will be increased by 30 per cent.
(ii) there are already a number of garbage grinders operating in kitchens of some hotels. Contribution to pollution load by these limited units is insignificant, as provision of grease traps is required in the drainage systems of hotels. Usage of these units in hotels and restaurants may be permitted.
(iii) it is anticipated that these units will not be widely used in local domestic buildings because of the high cost for installation. The situation should be reviewed, however, say in 5 years' time with the intention to make new or amend Regulations or Ordinance to prevent further installation of these units, if this should be found necessary, at that time.
If usage of these units were to be encouraged, pollution load discharged into public sewerage system would be greatly increased. As a result, the requirement of sewage treatment plant would have to be advanced, and additional plant would be required. It is estimated that the cost for the treatment of food waste discharged from garbage grinders will be in the order of $75 per ton.
Based on current costs, disposal of refuse by either incineration or controlled tipping varies between $25 to $30 per ton, which includes transportation.
From drainage and engineering points of view, usage of these units will not overload the flow capacity of the existing sewerage system, although more frequent drainage chokages may occur. This Department maintains the view that general usage of these units should not be encouraged, as it is not economically viable.
Page 103 of 212
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Page 102 of 212
HONG KONG URBAN COUNCIL
Limited enquiries from importers of sanitary and electric appliances have not yet been able to establish whether these units are on sale in Hong Kong, and it has not been possible, therefore, to estimate the total cost of an appliance and its installation; (b) additional demand for water is created by the use of these units. In the United States of America where they were first introduced, this has been estimated to be in the region of one gallon extra per person per day;
(c) if the disposal units were installed in large numbers, they could have an effect on the sewage systems, as there would be a great increase both in the amounts of water flowing through the sewers and of solids present in the content;
(d) most of the sewage in Hong Kong is discharged into the sea, especially the harbour, for disposal. If mechanical water-borne waste disposal units were brought into general use without the sewage and garbage being subject to primary treatment, increased pollution of the harbour and beaches would pro- bably result as, unlike human waste and toilet paper which is soluble, much of the domestic garbage, for example potato peelings and food waste, is not readily soluble and would take a much longer time to decompose. The resultant effluent from these units, therefore, could contribute to an increase in water pollution, especially visual pollution.
From the Departmental point of view, the mechanical garbage disposal units in kitchens are hygienic (since there would be much less offensive matter deposited into household dust-bins) and they would reduce the bulk of refuse re- quired to be handled by our staff; but at the same time the amount of sewage to be moved from the primary sewage treatment plants in the form of liquid sludge would inevitably be increased and would present addi- tional problems in the further treatment and disposal of the sludge.
As Members will no doubt be aware, restaurant and eating- house food waste finds a ready sale to pig-breeders. As this forms the bulk of the garbage which could be dis-
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posed of by mechanical disposal units there would appear to be little point in requiring licensed restaurants to install these units as a condition of licensing.
Finally, in response to the last part of the question, the Department has consulted the Director of Engineering Development for his initial comments, which are that in late 1971 a study on the feasibility on local usage of these disposal units was carried out. This concludes that:-
(i) if the whole community were to use these units the pollution strength or degree of the sewage will be increased by 30 per cent.
(ii) there are already a number of garbage grinders operating in kitchens of some hotels. Contribution to pollution load by these limited units is insigni- ficant, as provision of grease traps is required in the drainage systems of hotels. Usage of these units in hotels and restaurants may be permitted.
(iii) it is anticipated that these units will not be widely used in local domestic buildings because of the high cost for installation. The situation should be reviewed, however, say in 5 years' time with the intention to make new or amend Regulations or Ordinance to prevent further installation of these units, if this should be found necessary, at that time.
If usage of these units were to be encouraged, pollution load discharged into public sewerage system would be greatly increased. As a result, the requirement of sewage treat- ment plant would have to be advanced, and additional plant would be required. It is estimated that the cost for the treatment of food waste discharged from garbage grinders will be in the order of $75 per ton.
Based on current costs, disposal of refuse by either incineration or controlled tipping varies between $25 to $30 per ton, which includes transportation.
From drainage and engineering points of view, usage of these units will not overload the flow capacity of the existing sewerage system, although more frequent drainage chok- ages may occur. This Department maintains the view that general usage of these units should not be en- couraged, as it is not economically viable.
No comments yet.
Private notes are available after approval.