HH62/1/M-LOTH/19

Transcription

[Page] 18

POLLUTION FROM LIMESTONE MINING.
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.

POLLUTION FROM PARAFFIN OIL WORKS.
The solid matters at such works which are liable to
pollute streams are mainly -
(1) Tarry matters, the cleansings of plant -
pipes, etc.
(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, naphtha, 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
employed:
(a) In the various distillations of the oils,
and afterwards separated by Separators;
and
(b) In the cleansing of naphtha from melted

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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
escaping decomposition, is separated from
the crude oil by Separators, which allow
the oil to float and pass off above, and
the water to be drawn off from below.
This water is afterwards exhausted of its
ammonia by heat, and the ammonia is
recovered by sulphuric acid.
(4) Water used for condensing the oil vapours,
and which may either be a pure water
such as (1), or dirty water of the works
cooled in cooling ponds for the purpose.
(5) Water used for cooling the paraffin in the
candle moulds, in candle making.
(6) Water employed in dissolving the caustic
soda used in refining, and afterwards
separated from the oil.
(7) Water used for washing out the vitriol from
the vitriol tar, and afterwards separated
from the vitriol.
(8) Surface drainage water -
(a) From rain, leakages in plant, spilling of
fluids, etc.
(b) From refuse bings.
In a work where the water supply is plentiful,
perhaps the simplest and cheapest method of dis-