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our staffs and weekly conferences are held between the Scientific Adviser and the Divisional
Engineer (Main Drainage), together with their senior officers, to discuss analytical results,
operational practice and research projects.
In addition to laboratory work undertaken to obtain the best efficiency from the treatment
plant, full attention was given to matters of safety. For example, the utilisation of
sludge gas involved daily safety tests at all potentially hazardous points in the digestion
plant, power house and domestic boiler room.
Trade waste discharges
The Council exercises control under the London County Council (General Powers) Act,
1953 over industrial discharges into the London sewerage system. These discharges have
increased in volume and complexity over recent years and continuous control is needed
to exclude substances which would be hazardous or damage the fabric of the sewers.
Detailed laboratory examinations were made on 2,795 samples of trade waste discharges,
about one-third of this number being submitted by twelve metropolitan boroughs. In
consequence of these examinations, officers of the Scientific branch and of the Chief
Engineer's department visited many premises to discuss with the occupiers the problems
involved in treating the discharges and to give advice.
During the year a working party of the Council and of representatives of the metropolitan
boroughs considered what further steps might be necessary to exercise a closer control
on trade waste discharges in the county. The results of their deliberations were embodied
in the London County Council (General Powers) Bill, 1962.
Drinking water
To ensure that the water supplies to Council establishments are of satisfactory quality,
the Scientific branch carries out regular monthly inspections and samplings at those
establishments where supplies are drawn from private wells. The water from these wells
is chlorinated before use by means of automatic dosing plant. Samples of both the raw
well waters and the treated waters are taken for bacteriological and chemical examination.
If pollution is suspected check samples are taken at frequent intervals.
At the request of the hospital management committees, the well supplies at some of the
hospitals formerly under the control of the Council have continued to be regularly
examined.
Because of the excellent system of drinking water examination by the Metropolitan
Water Board, samples are not examined direct from mains supplies but water from storage
tanks is tested in many institutions to check the internal system and to ensure that tanks
are periodically cleaned.
Air pollution
The Council continued its long-standing co-operation with the Department of Scientific
and Industrial Research in investigating the incidence of air pollution, by maintaining
regular observation of the degree of pollution of the atmosphere over the county. In recent
years these measurements have acquired a special significance in reflecting progress in the
implementation of the Clean Air Act of 1956.
Results obtained by the daily volumetric method indicated a further reduction in the
average pollution of the air during the year, as compared with the previous year, to the extent
of about seven per cent. in smoke and four per cent. in sulphur dioxide, despite the occurrence
in November and December of foggy periods which caused the average pollution
during these months to be worse. Except perhaps in local pockets, the concentration of
either of the two main pollutants never reached the level which would be regarded as
' smog ' ; the smoke concentrations, in particular, during fog reached little more than half
the level which has frequently been exceeded in fogs of the past.
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