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section, nine tenders ranging from £576,608 to £705,932. All tenders were subject to movements in
the cost of labour and materials, and other conditions were inserted by various tenderers. In order
to reduce the cost, negotiations took place with the tenderers for contracts upon a cost plus profit basis.
Ultimately the Council on 2nd November, 1920, decided to entrust contract No. 1 to the Metropolitan
Tunnel and Public Works Company, Limited, and contract No. 2 to Scott and Middleton, Limited,
and to pay, in each case, a sum to cover remuneration, establishment charges, etc., upon the understanding
that any saving in the actual cost of the work below the companies' estimates, after adjustment
for quantity and for variation in the rates of wages and materials, shall be shared equally between
the companies and the Council, and that the companies shall lose 20 per cent, of any excess in cost
over their respective estimates.
The improvement of the river Graveney is comparatively simple, and is a work for which a fair
amount of unskilled labour will be required. In view of the great amount of unemployment the Council
on 23rd November, 1920, decided to invite tenders with a view to the work being expedited.
Tenders will be upon a cost plus profit basis with a provision for comparing cost with estimate and
sharing any difference between the Council and the contractor.
A site has been acquired for £6,520 for the pumping station for the proposed relief works in Hammersmith.
The position of the outlet of the sewer necessitated negotiations with the Port of London
Authority and the Authority's certificate under section 28 of the Metropolis Management (Amendment)
Act, 185S, has been obtained to the plans.
Dwelling
houses on
low lying
lands.
Part III. of the London County Council (General Powers) Act, 1920, takes the place of Part XI.
of the London Building Act, 1894, and provides that, except with the Council's consent and subject to
such conditions as the Council may require, no building for use wholly or in part as a dwelling house
may be erected or re-erected on land, below the level of Trinity high-water mark, which cannot be
efficiently drained at all times by gravitation into an existing sewer of the Council, Two such cases
were dealt with between the passing of the Act on 4th August, 1920, and the end of that year.
Buildings',
etc., over
sewers.
Under section 204 of the Metropolis Management Act, 1855, and section 68 of the Metropolis
Management (Amendment) Act, 1862, no building or any other encroachment may be erected in, over
or under any sewer vested in the Council except with the Council's consent. During 1920 the Council
gave its consent in twelve such cases.
Discharge
into sewers.
Part IV. of the London County Council (General Powers) Act, 1894, prohibits the discharge into
any sewer under the control of the Council, or into any drain or sewer communicating therewith, of solid
matter or refuse, except such as is contained in ordinary house sewage, or offensive liquid refuse, or
steam or hot water of a higher temperature than 110° Fahr. Legal proceedings were taken in two cases
of discharge of heated water. In one case the defendants were fined £20 and ordered to pay £5 7s.
costs, and in the other the summons was dismissed, but an application for costs against the Council
was refused.
Local
sewers.
Section 69 of the Metropolis Management Act, 1855, provides that no local sewer shall be made
without the approval of the Council. During 1920 the construction or reconstruction of 7,0334 feet
of sewers of various sizes has been sanctioned.
When plans of local sewers proposed to be constructed at various housing estates were submitted
for the Council's approval, the use of concrete under or around such sewers was not specified, but it was
proposed to lay the pipes directly upon the bed of the trenches. This omission, except in special circumstances,
was the result of instructions issued by the Ministry of Health. In the Council's opinion
the value of this use of concrete had been abundantly proved ; sewers laid without this safeguard would
be extremely liable to become disconnected, and sewage would soak into the soil with serious results.
The Council declined to associate itself with the adoption of such proposals or to approve plans of sewers
in which concrete was not used. Subsequently the Minister of Health decided that sewers in London
should be encased in concrete except when officials of the Council and the Ministry agreed that this was
not necessary.
Sludge
vessels.
The Council has six sludge vessels which were launched at different dates between 1887 and
1895. The oldest vessel is the s.s. Bazalgelte, and if she were to be retained in commission new
machinery was required and also extensive structural repairs to her hull. The question of spending
a large sum upon so old a vessel was carefully considered, but the conditions in the shipbuilding trades
made the cost of a new vessel prohibitive. It was estimated that, if repaired, she would have a further
life of 15 years and tenders were invited, for the work. Only one was received and that was not
considered to be satisfactory. The Council on 18th May, 192) decided to arrange with Vickers,
Limited, the builders of the vessel, to undertake the work upon a basis of cost.
Sewage
treatment.
The overhaul and quadrennial survey by Lloyds of the s.s. Bmme, Barrow and Belvedere became
due during the year, and the total estimated cost of work required to these vessels amounted to £17,000.
Much pioneer work in the biological treatment of sewage was done by the Council's officers, and
before the war important questions arising out of their experiments were being considered. A new
process was then being developed which, by prolonged aeration of sewage, produced an inoffensive
sludge, quite different from ordinary sewage sludge, and an effluent of excellent quality. This treatment,
generally known as the "activated sludge" process, alters the physical and bio-chemical features
of the suspended matters, and they become purifying agents. Successful resufts on a small scale were
obtained in the Council's laboratories, but the outbreak of war suspended the work. Early in 1920 the
work was resumed and the Main Drainage Committee visited Sheffield, Manchester and Worcester,
where further experiments in this treatment were being worked upon a practical scale. At all these
plaeas the general principles were the same, but at Sheffield different mechanical means were adopted.