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A simple arrangement of "dust-catcher" has been designed and is described on page 3. The usual height of chimney for natural draught furnaces has been provided, probably in con- sequence of the proximity of the Slaughter Houses.
The Horsfall Syndicate.
The scheme of the Horsfall Syndicate is very complete. The furnace is of the better type having the outlet flue in front and twelve cells have been provided on the basis that each will be capable of burning 7 tons per diem.
Provision has been made for storing the refuse on the works in trucks, which can be run on rails and tipped, the refuse being thus discharged into the furnaces without additional handling.
The furnaces are divided into two sets and the forced draught, although not entirely free from the objections previously urged, is well arranged.
The boilers are placed as close to the furnaces as possible and are thus in the best position to utilize the available heat.
A "dust-catcher" or beehive cremator, as working successfully at Edinburgh, has been provided for while the chimney is but little more than half the height of that proposed in the other scheme.
Special provision has been made for drying blood (for manure) and arrangements have also been made for fixing an economizer to heat the feed water to the boilers.
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Comparison.
For comparison I propose to describe the scheme of the Horsfall Syndicate as the "Horsfall" and that of Messrs. GODDARD, MASSEY AND WARNER as the "WARNER."
Comparing the two schemes it will be observed that, on the principles laid down on page 2, the Horsfall type of furnace is the better of the two. The Horsfall Syndicate guarantee to burn 71⁄2 tons per cell per diem as against 9 tons estimated by Messrs. GODDARD, MASSEY AND WARNER; I have seen both kinds working and from observations and from enquiries I am confident that the former will burn as quickly and as well as the latter.
There is a considerable difference in the estimated cost per cell. For instance-
12 Horsfall cells and flues, .........£4,380.18.4
Forced draught,
270. 0.0
10 Warner cells and flues, ......£2,522. 0.0
Forced draught,....
£4,650.18.4. = £387.11.6 cost per cell.
£2,997.10.0. £299.15.0
475.10.0 (£2,997.10.0.
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The size of the cells being practically the same, it seems probable that the difference in cost is to be accounted for mainly by a different price being adopted for workmanship and materials, and that the ultimate cost in Hongkong of either design would be much the same.
In the "Warner" design it is arranged to use the platform over the clinkering space as a tipping platform and this might equally well be done in the Horsfall scheme. The latter scheme, however, to conform with the specification, has provided a special tipping platform and storage bay with rails, and waggons sufficient to hold the refuse of one day, in order as requested to minimize the handling, and the cost of this must be deducted in comparing the two estimates.
The boilers should cost the same whichever scheme is adopted, but as I do not recommend obtaining boilers from England in the first instance, their cost may also be eliminated. I have already pointed out that they are better placed in the Horsfall scheme than in the Warner.
The Horsfall scheme proposes a chimney only 100 feet high, which, with forced draught and their patent dust-catcher, is claimed to be equally effective with a higher chimney and results in an estimated saving of £850 over that of the Warner scheme.
The buildings with platform are nearly the same size in both schemes, but are again priced higher in the Horsfall estimates, but as in the case of the furnaces it is probably that the ultimate cost in Hongkong would be much the same.
To sum up, both schemes have been carefully worked out, but I am of opinion that the "Horsfall" scheme is the better of the two in type of furnace, in general arrangement, and in detail.
RECOMMENDATIONS.
From the foregoing it will be seen that in my opinion
(i) The present method of disposal constitutes a danger to the health of the Colony. (ii) The alternative of barging to sea, although an improvement on the present method, still
has the great objection of delays by tides, storms and typhoons.
(iii) Burning is the most sanitary method of disposal and therefore the right one to adopt. With our present limited knowledge, it would be wise in the first instance to experiment by burning a portion of the city refuse, before deciding on a scheme for disposing of the whole. These experiments might last for one year, during which time the remaining portion of the refuse would continue to be barged to the mainland as at present.
For the purposes of these experiments, I recommend the erection of four Horsfall cells with flues, dust-catcher, chimney and the necessary buildings, at Kennedy Town, on a convenient site near the Slaughter Houses and Infectious Diseases Hospital. With this plant can be ascertained the quantity