View report page

51
caries. This has been followed by a reduction in the incidence of dental
caries in younger children to the level of those drinking water with a
naturally-occurring fluoride content. Four places in the British Isles,
Watford, Darlington, Anglesey and Kilmarnock have accepted an
invitation to add fluorine to the public water supply. One of the objects
of the mission to North America was to determine what hazards there
were. On this they reported there is no scientific evidence that there is
any danger to health from the continued consumption of water containing
fluoride in low concentration. Many factors will influence the effects of
the consumption of water to which fluorides have been added so that
results as striking as those obtained elsewhere will not necessarily be
seen here. Nevertheless some reduction in dental caries to the level of
those living in high fluorine areas in this country might reasonably be
expected.
DRAINAGE AND SEWAGE DISPOSAL
Sewerage
Until 1935 all the work of maintaining sewers and purifying sewage
in Middlesex was carried out by the local authorities for each particular
district. The sewage from Harrow-on-the-Hill Urban District was
treated at the sewage farm, Newton Farm, Rayners Lane. The sewage
after screening was passed through detritus tanks on to sedimentation
tanks. The effluent was then distributed on the land by the system of
broad irrigation, the final effluent discharging into streams leading to
the Yeading Brook. The sewage from the Wealdstone Urban District
was treated at the sewage disposal works at Elmgrove Road. These
works comprised screening chambers, detritus and sedimentation tanks
and percolating filters fitted with rotatory distributors. After passing
through humus tanks, the effluent was discharged into the Brook. There
were three sewage works in the Hendon Rural District. At the works
at Cannon Lane, Pinner, which took the sewage from Pinner and part
of Harrow Weald, the sewage after passing through sedimentation tanks
passed through percolating filters and humus tanks, the effluent discharging
into the Yeading Brook. Most of the sewage from the Parish of Great
Stanmore was treated at the sewage works at Honeypot Lane, being
treated by sedimentation and broad irrigation, the effluent discharging into
the Edgware Brook. The Little Stanmore sewage works took the sewage
from Little Stanmore, the southern part of Great Stanmore and part of
Harrow Weald. The sewage passed through sedimentation tanks,
percolating filters and humus tanks, the effluent being discharged into the
Hendon Brook.
With the building development in many parts of the county, local
authorities found difficulty in extending their sewage works to cope
with the ever-increasing volume of sewage to be dealt with. The local
authorities, therefore, agreed to the County Council obtaining powers
by special Act of Parliament to make provision for the main drainage
and the purification of sewage from an area embracing the whole of the
western part of the county.
The West Middlesex Sewerage District. This district included
15 sanitary districts served by 28 separate local sewage works. The new