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30
of the Dagenham Urban District Council), and were
designed only for the partial treatment of a
maximum flow of 1 m.g.d.
Simultaneously with the demand for increased
flow capacity of the works, the Port of London
Authority demanded increased purity of the effluent
and also provision had to be made for considerable
flows of trade waste from Messrs. Ford's and other
factories.
About 1931, therefore, designs were prepared
for a new works to give a high degree of purification
to a D.W.F. of 3 m.g.d. domestic sewage, by means
of sedimentation and activated sludge treatment;
provision also being made for partial treatment of
a flow of 2 m.g.d. trade waste from the Ford factory.
The required standard of the Port of London
Authority is being met by the discharge of the
highly purified domestic effluent mixed with the
partially purified trade waste—a system which has
proved quite satisfactory in operation.
A new pumping station was provided to deal
with the domestic sewage flow, whilst the old station
was converted to deal with the trade waste arriving
from Ford's by a separate sewer.
The original settling tanks have since been
adapted to work in parallel with the new sedimentation
tank and provide further settlement capacity
in the domestic section of the plant, pending
construction of further extensions to meet increasing
flows, now in the region of 4 m.g.d. D.W.F.
The present works thus consist of two pumping
stations, separately lifting domestic sewage and
trade waste, and for the treatment of the
domestic sewage, a radial flow mechanical sedimentation
tank with six plain rectangular sedimentation
tanks in parallel for balancing flows, followed by
activated sludge treatment with simplex aeration