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but its available capacity would be more fully used and fever barges would be required for operation of this method in comparison with the first. Also, owing to the fact that the circulation of the containers would take a shorter time in this second procedure, a smaller number of containers would be required; this is an important factor for consideration in relation to the provision of now standard pails for extension of the 2-pail system of collection.
A third method to which I have given some consideration would be to disintegrate nightsoil at a dopot on the Kowloon sido and pump it through a pipeline to the composting installation. Purrping of sewage sludge over long distances occurs in some big sewage treatment plants, notably the West Middlesex Main Drainage Scheme, in which partially digosted sludgo is pumped seven miles through a pipe at a low gradient; pumping is suspended overnight and the sludge remains stationary but no trouble has been experienced, in a period of over twelve years, from deposition or blockage. I am aware that nightsoil, diluted with water from the cleansing of pails, would be a more troublesome liquid than digested sludge, and it has to be borne in mind that the volume of nightsoil liquid to be pumped would be such that, in the smallest size of pipe which would be practicable for the purpose, the nightsoil would be more than 24 hours in the pipe before reaching a composting installation as far away as Tsun Wan, I propose, however, to give further consideration to the practicability and cost of this method, which would undoubtedly be the most hygienic. There would be no opportunity for flics to breed during transit of the nightsoil. The method would be independent of weather conditions, so far as Kowloon was concerned, although barges would remain the best method of bringing nightsoil from Hong Kong across the Harbour. There would be a consequent decrease in the opportunity for illicit disposal of nightsoil such as, I understand, occurs during barge journeys. Another potential advantage of this method would be that, when the pail syston was dying out, some of the new outfalls on the Kowloon side could be connected with the pumping station by subsidiary pipelines through which screen washings, sludge or sewage could be delivered for pumping to the composting installation.
For the present, I am basing my proposals upon the second method which is the preferable one of the first two methods.
2. The urban depots for nightsoil. At present cach nightsoil barge
station consists simply of an open mooring place for the barge, with a gang plank across which the pails are carried for stowage on board. None of the special arrangements required for the emptying and cleansing of pails yet exists. New stations to provide these facilities are needed. These stations could be on the water front over barge moorings or could be inland with sumps to collect the nightsoil and wash water and with purps to deliver the liquid to the barges.
I propose that at these new depots a chain conveyor should be provided to receive the standard pails as they are unloaded from the collection vehicle. A workman would unfasten and remove the lid of each pail for disinfection, but a type of fastener might be devised which could be released mechanically, the lid being taken away by a subsidiary conveyor through a trough of disinfectant. The pails would be automatically turned over to discharge their contents and, still in the inverted position, would pass over the water jets. The first flushings of foul water would be piped to the nightsoil barge or the sump. The pails, still moving on the conveyor, would remain upside down to be sprayed with disinfectant and to drain, before being righted, covered and delivered ready for loading into a collection vehicle.