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(a.) Extension of Sewage Works.
I am indebted to Mr. J. Bowen, the Borough Surveyor and
Engineer, for the following particulars:—
There has been no material alteration to the sewerage
system of the district during the last twelve months. As
you are aware, improvement works are in course of construction
as approved by the Ministry of Health on 19th
March, 1923, consisting of the following:—
1. The provision of six circular percolating filters 98ft. in
diameter capable of dealing with approximately
460,000 gallons of sewage in twenty-four hours when in
use as primary and secondary filters. Diverting
apparatus has been provided in order that, when the
sewage is to be treated over three times the dry weather
flow, the filters will all become primary. Distributing
chambers have been provided which also act as humus
chambers. In excess of these two, special humus tanks
are provided after the filtration has taken place
approximately 30ft. in depth, the capacity of each being
6,330 cubic feet.
2. Difficulty has been experienced in the past owing to the
original six precipitation tanks being arranged so that
sludging could not be carried out without putting
most of the tanks out of action. The walls of these
tanks have been raised, so increasing their capacity to
approximately 100,000 gallons. The conduits, weirs,
valves, etc., have been arranged in such a way that the
tanks can be worked either in series or in parallel at
will and any unit may be sludged without interference
with either of the others. A very material improvement
has been experienced since these have been at
work.
3. A new air compressor of 350 cubic ft. per minute
city has been installed which can be driven either by
electricity or suction gas plant. This will be capable of
dealing with two outlying districts, one approximately
three-quarters of a mile and the other a quarter of a
mile from tha Pumping Station where the power is
generated. At the same time it duplicates the horse
power which was originally installed.
4. Gauging apparatus, whereby both the flow of sewage and
the flow of air can be recorded, and other instruments,
have been installed.
5. Alterations and improvements to the sludge tanks,
including the covering in of the exposed portion and
supplying adequate ventilation have been carried out.
6. One-and-a-half acres of allotments situated on the
east side of the Sewage Farm have been reclaimed for
the extension of the filtration area.
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