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should be used for flushing. The method is proving a success and will be intro
-duced to other commands.
The Sewage works at Quetta. —Parts of the purification plant have been
redesigned to provide from one old settling tank a sludge digestion chamber,
improvements have been made in the filters and in the final disposal of sludge
and effluent.
The Sewage project at Wana had a setback owing to the fact that subsoil
irrigation in the Wana soil appears to be incapable of dealing with the effluents
from the septic tank disposal plants. Regretfully the pail and incineration
were reintroduced.
The Sewage project at Thal. —A new sewage disposal plant for the new
buildings had been devised and would have been a great advance in benefitting
the station. Sanction had been accorded but the war broke out and so pail
latrines and incineration have been provided for barracks and septic tank
disposal for all bungalows and quarters.
Septic Tank disposal of effluents from hospitals. —This question was raised
by the Engineers in connection with building septic tank disposal plants
for hospitals from which disinfectants were emptied into the drainage system.
Carefully checked enquiries were made. These included a series of laboratory
experiments and full scale tests which were extremly well done by R. A. M.
C. Officers at three of the largest military hospitals near which a district
laboratory was available.
It was shown conclusively that in the normal sewage effluent from a
hospital the dilution was quite sufficient, 500 to 1, to eliminate any inhibitory
action, by the disinfectant. A 300 to 1 dilution appears to be sufficient, the
average hospital dilution is 1000 to 1 or more.
The question of size of the septic tank was also raised and the conclusion
reached that for military hospitals a 1 day's capacity at 30 gallons per bed per
day should be given, the tanks being 3 to 4 times longer than broad and not less
than 4 feet deep with 1 foot extra depth to allow for sludge. When only the
water closet and slophopper sewage goes to the septic tank system 12 gallons
daily should be allowed with a 50 per cent addition in relative size.
Sewage effluent disposal.—At Quetta complaints had been received and
difficulties raised by civil authorities on the disposal of sewage effluent from
the military sewage works into the Lora River (a method of disposal common
in all countries). In order to refute objections and serve as a record for the
future careful examinations kept during the year showed the following:
—
The Sewage effluent was at all times good and except in August was
actually of better quality than the Lora River water.
The Lora River water was typical of that of an open stream freely con
- t a m i n a t e d a n d w a s e x c e p t i n A u g u s t o f w o r s e q u a l i t y t h a n t h e
effluent.
The Habib Nulla, a typical drain nullah passing down between canton-
ments and the city to finish in the Lora River, was always grossly
contaminated and of very bad bacteriological quality.
It was quite obvious that the discharge of our sewage effluent could have
no harmful effect on this river water.
Conservancy at Aurangabad.—At Aurangabad conservancy is carried out
efficiently by motor transport—separate lorries are available for rubbish, night
soil and sullage.
Latrines for families quarters and for followers. —At present there are two
arrangements. The single latrine to every quarter and the group latrine for