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At Kingston-upon-Thames the primary object of a destructor should be to render refuse
innocuous by an innocuous method. It is therefore essential that the destructor selected shall be
capable of subjecting the refuse and the gases to a sufficiently high temperature for a sufficiently
long time, and that no nuisance shall arise from the building, or from the emanations from the
chimney top. After these essentials have been fulfilled, use may be made of the products of
combustion, to generate steam, or to utilise the clinker, fine ash and flue dust, but this use must be
only secondary to the complete destruction of refuse.
The first and most essential requirement, the complete oxidation of the refuse and of the gases,
is obtained by the high temperature maintained by the forced draught, or by steam jets. In
contrasting the forced draught by fan with the steam jets, I believe in Kingston that the fan would
be preferable, as it could be used to extract the more or less offensive air from over the tipping
platform, and further because its working would not use as much steam as the steam jets, the use
of steam jets would prevent the use of the fan for removing the offensive air.
Mr. Watson, m.i.c.e., estimates that the amount of steam required for the steam jets is about
5½ horse power compared with 1 horse power to drive the fan.
The arrangement of the furnace cells may be, as already stated, either back to back or in rows;
experience shows that though equally good work can be done with either arrangement, the single
row cell plan has certain practical advantages in being more open for inspection, cleaning and repairs.
The working expenses of a destructor can be considerably reduced by making use of the
products of combustion, which are heat, clinker, fine ash and flue dust.
The heat is used to generate steam, watertube boilers being usually adopted, and though the
power varies with the quality of the refuse, 60 or more horse power per pair of cells is obtainable.
This power may be used :
To drive fans for forced draught.
To supply steam jets.
To grind mortar and clinker.
To pump water or sewage.
To aid electric lighting.
To aid electric traction.
The heat also provides for the Borough a valuable means of safely destroying infected bedding,
condemned provisions, carcases of diseased animals, &c.
The clinker can be made use of in many ways. It is quite innocuous and could be used to fill
up gravel pits, or tipped into Maiden ponds without fear of causing a nuisance.
The clinker averages ¼ in bulk, l-3rd in weight, of the original refuse dealt with. It is
frequently when ground, mixed with lime for mortar, clay for bricks, or placed under sets as a bed
for pavements. (Clinker mortar sells for about 5/- per ton).
It is also used for filter beds for the bacterial process of treating sewage.
Clinker may be used for making road bottoms, or broken and mixed with cement (one part of
cement to three of broken clinker) to form concrete, which is then shaped into paving stones. These
stones have a disagreeable dull colour, but this has been rectified by washing the surface, after the
slabs have been laid, with a strong mixture of cement and water, which it is stated " takes some
time to wear off." Their appearance has also been altered by forming a mosaic pattern by the
mixture of pieces of broken china, etc. The sizes of these slabs are usually 2ft. by 2ft., and 3ft.
by 2ft., being 2½ inches thick. The total cost of production is about 1s. 73/4d. per square yard ;
they take from six to nine months to set after removing from the mould, they are then very hard.
In Southampton after twelve years wear, in busy streets, the slabs showed not more than -8th
inch wear, and experiments have shown that the breaking weight of slabs made of cement and
clinker is much higher than of slabs made of cement and the best Thames sand.
The Kingston Corporation are at present paying 5/4 per square yard to the Imperial Stone
Paving Co.; this includes the price of the stone and the cost of labour. At Bristol the sides and
bottom of one of the Corporation baths have been lined with a mixture of cement, clinker and
chalk, " forming a clean, bright, and impervious lining ; easily cleaned." Steps, flags, window
sills, pillar blocks, etc., have also been made of this mixture.
The Fine Ash. This is mostly collected from below the furnace bars; it is estimated that
3½ cwt. of fine ash result from 100 tons of refuse. It is used for mixing with clay for garden and
for brick making purposes ; at Leyton it sells at 1/6 per load.
Flue Dust is of a peculiar fine, sharp character. Sir Douglas Fox in his report estimates
that 18 grains are contained in a cubic foot of air in the combustion chamber; as 5,000 to 6,000
cubic feet of air pass from the chimney top per minute, this would amount to about three cart
loads per week poured into the air, if arrangements were not made for catching it in "dust
catchers," and in the flues; three cartloads a week is about the average which is caught, and it has
a distinct commercial value. In Leyton it sells at 4s. per cart load, and is sold for making