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76
Greenwich
Power
Station
Laboratory.
The work of the laboratory at the Greenwich power station comprises:—(i.)
The daily examination of samples of water and materials with a view to the control
of the water-softening plant, the blowing-down of boilers, the detection of condenser
leakage, and advice on such matters as the purity of condensed water supplied to
the station batteries; (ii.) the sampling, preparation and examination of samples
of fuel (coal) used both at the power station and at other works of the Council, such
as the main drainage outfalls and pumping stations; the preparation and examination
of samples of fuel ashes, etc.; and (iii.) investigations connected with corrosion of
metals and other matters affecting the operation of the station plant.
Outfalls.
At the outfall laboratories systematic daily examinations of the sewage reaching
the outfalls and the resulting effluent and sludge, as well as of the water of the river
Thames at both high and low tides, and other analyses in connection with the
working of the outfalls have been continued. Much attention has also been given
to chemical work relating to fuel economy and systematic examinations of fuel,
feed-water, etc., are now made on lines similar to the work at Greenwich power
station. In addition much experimental work needed to throw light on matters
connected with the river, or sewage treatment, has been undertaken at these
laboratories.
Biological
treatment of
sewage.
The experimental treatment of large volumes of sewage, and, later, of large
volumes of effluent by mechanical agitation has been continued with uniformly
satisfactory results. Further points in connection with this mode of treatment
need elucidation and are being investigated. It has been found that the treatment
and reactivation sections of the combined plant are capable of treating 300,000
gallons of effluent a day. The insufliciency of the present settling tanks so far
appears to be the limiting factor.
River Lee.
This river was visited and chemical examinations made of the water in July
and again in October. On both occasions it was found to be, from Tottenham lock
downwards, in a very unsatisfactory state. It is clear that this condition is likely
to continue until the effluents brought down by the intercepting ditch which receives
the Pymmes brook and other streams, are improved and the lesser pollution from
the small brooks, discharging through or near the old Tottenham sewage works,
is stopped. The natural river below Lea bridge, where it passes by Hackney marsh
and forms the County boundary was in a dirty condition in October. The rapid
flow of this shallow stream causes it to be in part self-cleansing but there is much
room for improvement.
River
Thames.
The systematic examination of the river Thames was continued in 1925, at
points from Waterloo bridge to the Edinburgh lightship, which is in the vicinity
of the discharge area for sludge from the Council's outfalls and for waste matters
discharged by other bodies.
Provision has been made for additional treatment of sewage at the outfalls,
and in view of the condition of the river it became necessary to use iron salts at
both outfalls for about a month beginning on 4th August.