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27
Drainage and Sewerage
Separate systems of soil and surface water drainage continue
to operate in the Borough, but the East Middlesex drainage scheme
is likely to have some future bearing on the matter. The preparation
of plans is nearing completion and it is probable that work
on the Tottenham portion of the scheme will start in 1956.
The operation of a dual drainage system gives rise to
repeated problems in the prevention of pollution of streams by the
surface water sewers discharging into them. The following paragraph
outlines the steps that have been found necessary in tracing
sources of surface water pollution.
Stonebridge Brook Pollution
Following further complaints from the River Lee Conservancy
Catchment Board of pollution of the Stonebridge Brook, it was
decided by the Health Committee to intensify investigations into
the possible sources of pollution. At first it was thought
possible to carry out this work with existing staff but later it
was found necessary to employ additional staff.
Samples taken at a number of points on the surface water
drainage system showed that sewage pollution was occurring. In
addition traces of cyanide were discovered indicating that industrial
waste was finding its way into the surface water drains,
Intensive efforts were made to locate, if present, any general
pollution caused by soil connections wrongly discharging into the
surface water sewers; and special visits made where it was known
that trade processes involved the use of cyanide, e.g. electroplating
and case hardening.
In no industrial premises was it established that drains were
wrongly connected; and the more probable cause of industrial
pollution was the misuse of the drains, e.g. by workmen throwing
waste matter into the surface water drains or floor washings being
brushed into them.
In the investigations into the presence of general pollution,
2,538 visits were made and 160 illegal connections to the surface
water drainage system discovered. Preliminary notices were
served requiring these connections to be made to the soil drainage
system and, where necessary, statutory action was taken.