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overhead structure should be as low as possible in relation to the barges, and it would be unreasonable to have to make the structure of such a depot high enough to provide clearance for the whoolhouse and flagstaff which are a feature of the new stool dumb barges,
It will also be for consideration whether crew's quarters would be required on the barges, as a quicker turn-round should be achieved with now mechanisod loading and unloading arrangements.
In such circumstances as I have described in the two proceeding paragraphs, it might prove feasible to revert with advantage to a hold-loading type of barge.
5. The composting installation. At the composting installation, night-
soil would be withdrawn from the barges, either by pneumatic equipment, for nightsoil in the crude condition, or by a suitable pump, for nightsoil previously disintegrated at urban depots, and passed to a temporary storage tank for supply as required to the composting process.
Digestion of the nightsoil before its incorporation in the corpost would yield gas for use as fuel in engines to provide a worthwhile proportion of the power required in the installation, but I cannot make a definite recommendation about the provision or non-provision of digestion plant until the discussion of this report has thrown more light upon the question of the rate at which the quantity of nightsoil available is likely to diminish and upon the quantity of sewage material likely to be available from now outfalls as an alternative to nightsoil.
I favour mechanical grabs for unloading the refuse barges and transferring the refuse to a tenporary storage hopper. The method is speedy and I believe that, at some sacrifice of pay-load, timber or other suitable lining could be provided in the barges to protect them from damage.
As an alternative system for the refuse barges, it has been suggested by Mr. Sherriff (Chief Health Inspector (Sanitation)), that they should be divided into a number of cells of appropriate size by containers which could be lifted bodily out and tipped into the hopper at the composting installation. I shall certainly give full consideration to this suggestion as I proceed with the design of the installation,
From the hopper the refuse would be fed on to conveyor belts, wide enough for the material to spread out thinly and moving at a sufficiently slow spoed to enable salvageable and inorganic articles to be observed, removed by hand and thrown into bins for further attention and disposal. Magnetic equipment would lift out ferrous metal articles, The compostable garbage would fall from the ends of the belts into shredding machines capable of tearing and smashing up the material into fragments.
From this point either of two alternative procedures could be adopted, I shall refer to these procedures respectively as
the batch method and the continuous flow method.
(i) The batch method is, in principle, identical with the procedure followed in the composting work already being done at Tsun Wan. For this method, the pulverised garbage would be dosed with nightsoil and a sprinkling of lime, inoculated with some active compost and then passed through a rotary mixer to a system of conveyors or other mechanical handling equipment for distribution of the mixture in the initial composting compartments,