[Page] 18


From the nature of the composition of sewage, it
rapidly oxidises on entering a stream, the water of
which, on running some distance, is rendered com-
paratively pure, excepting for potable purposes, when
there is always danger from the spores of disease
germs. When, however, large quantities enter from
villages, some form of sewage irrigation is called for.
This can be effected in most cases of sewage drainage
at present flowing into the river or its tributaries.


The minute division of suspended particles, and
their lightness, render cleansing of 'gum' wash only
possible by one means. A practical demonstration of
how this may be effected can be seen at Woodend
Colliery, near Armadale, where there is a very large
wash pumped into tanks dug in the refuse bings, and
regularly scraped out to prevent clogging. (I may
mention that the bings are largely made up of coke
refuse.) By this simple means the filtrate oozes out
at the bottom of the bings perfectly clear. Filtration
then, after some fashion, is the remedy for this


This source of pollution may be very easily pre-
vented by the construction of a settling pond. The
suspended matter is heavy, and settles rapidly.


The solid matters at such works which are liable to
pollute streams are mainly -

(1) Tarry matters, the cleansings of plant -
pipes, etc.

[Page] 19

(2) Vitriol tar, the cleansings of the oils treated
with sulphuric acid.
(3) Soda tar, the cleansings of the oils treated
with caustic soda.

The vitriol tar is washed with hot water to secure
the vitriol for further use, and the tar along with the
soda tar is in most works burned, and in some works,
as that of Broxburn, utilised as fuel by being blown
into the furnaces along with steam. This satisfac-
torily disposes of the bulk of such matter, although
small quantities in some works often escape and find
their way into streams.

The water at a Paraffin Oil Work, in which crude
oil, sulphate of ammonia, naptha, burning and lubri-
cating oils, paraffin and paraffin candles are manufac-
tured, may be stated to be as follows:-
(1) Clean water used in the boilers for gener-
ating steam.
(2) Water resulting from condensation of steam
(a) In the various distillations of the oils,
and afterwards separated by Separators;
(b) In the cleansing of naptha from melted
paraffin in the process of refining the
latter. This water is a comparatively
small quantity.

(3) Water manufactured in the process of de-
structive distillation of the shale, amount-
ing to about 30 to 40 gallons per ton of
shale used - which water, plus water
(other 30 to 40 gallons per ton of shale)
resulting from condensation of the steam
blown into the shale in the retorts and

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