View report page

35
was extremely poor in the summer months. It was difficult to assess the ma gnitude of the
effect of the chlorination of effluent for, although an equivalent reduction of chlorine
demand was proved, the variation in fresh water flow to the river also came into
question, as did also the progressive deterioration which has occurred i n recent years.
There was, however, evidence on a few occasions of a very slight improvement in the
neighbourhood of the Northern Outfall Works which could presumably be attributed
to the chlorination.
There are now two Government Committees considering and investigating the
condition of the River Thames; the Thames Survey Committee of the Department
of Scientific and Industrial Research set up at the request of the Port of London
Authority in June, 1949, and the Heated and Other Effluents Committee of the
Ministry of Housing and Local Government set up early in 1951 with wider terms of
reference. The Chemist-in-Chief is a member of both these Committees.
Close liaison was maintained with other research work both in this country and
in the United States on the problems of sewage treatment and river sanitation.
The laboratories at the two outfall works carried out the chemical analyses
necessary for the control of the various plants during the year. Research work was
also done on several aspects of the sewage treatment problem and particularly in
reference to the dewatering of sludge by a new process involving freezing after the
addition of chemicals. This was deemed to be of sufficient importance for the Council
to apply for patents both in this country and in the United States and for the construction
of a pilot plant to be authorised for larger scale investigations at the
Northern Outfall Works.
The question of trade discharges into sewers was investigated in a number of
cases as to compliance with the appropriate sections of the Public Henlth (London)
Act, 1936; one occurrence which caused the death of a sewer worker was proved to
have been due to a sulphide waste from one outlet coming into contact with an acid
waste from another; both discharges contravened a section of the Act. Advice was
also given in many instances as to whether a proposed discharge would be within
the terms of the Act, sometimes with suggestions as to possible pre-treatment which
would render it so.
Safety lamps used in sewers were tested and adjusted periodically and an officer
of the Chemical Branch gave advice and assistance in training men employed on
sewerage work in the use of oxygen breathing apparatus under emergency conditions.
The sewage treatment service is a joint function of the Chief Engineer's and
Public Health Departments and special mention should be made of the cordial
relations which have so greatly helped in maintaining the efficiency of the operations.
Weekly conferences of the Divisional Engineer (Main Drainage) and the Chemist-inChief
and their senior officers have been of the utmost value in this respect.
Housing
The amount of work done for this service increased still further during the year
and covered a very wide field. That on paints and other protective coatings included
the continued revision of the lists of firms and brands of materials which shall be
approved for use by the Council or for work done by contractors for the Council.
Many samples from manufacturers were examined for information and guidance of
the interdepartmental committees dealing with this matter; others were of paints
as supplied to works in progress. Generally it was found that an appreciable proportion
of the paint on the market did not comply with the standard of quality
required by the Council. Examples of reasons for adverse reports on samples were:—
(a) the use of white lead and lithopone together in a pigment;(&) the inclusion of
lithopone in a paint for exterior use; (c) gritty nature of the finished surface; and (d)
softness, or lack of adhesion and/or flexibility of the film produced. Special questions
investigated included the treatment of wooden structures to reduce inflammability,
the priming of hardboard, and the efficiency of the protection of iron and steel with
calcium plumbate (red lead has hitherto been used). Paint failures were examined
and reasons postulated with advice as to remedial measures.