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47
The area occupied with the land now belonging to the
Council by the works covers 72 acres.
The process adopted is, first, precipitation in tanks, the
sewage having previously passed through a screening chamber
and detritus tank. To aid this precipitation Sulphate of
Alumina is used. The clarified effluent then passes over the
high level filters, of which there are six, covering an area of
acres in all.
The filters are under-drained and ventilated. The
filtrate after passing through these is carried to the low level
"Contact Beds," which cover an area of 12,040 superficial
yards, are five feet deep, and consist from below upwards of
clean broken bricks, coke clinker, and pea gravel, the underdrains
are large perforated pipes, each line of pipes being
ventilated.
The liquid sludge is pumped on to certain portions of the
land and dug in.
In addition to the artificial filtering area mentioned,
there a.re 18 acres of land which can be used for irrigation
purposes.
The quantity of sewage flowing daily to the works in dry
weather amounts to about one and a half million gallons.
The reconstruction of the high level filters has had much
to do with the generally improved condition of the outfall
works.
The rapid increase in the population of the district has
rendered it necessary for the Council to acquire additional
land for the treatment of sewage. With this object an application
for a Provisional Order was laid before the Local
Government Board, and has since been sanctioned by that
authority and confirmed by Parliament.