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29
TREATMENT OF SEWAGE.
The question of better treatment of Sewage has, during the past
year, attracted considerable attention throughout the country, and it
has been my privilege to accompany some of your Members and officials
to various places to see different schemes in working order.
Without entering into any detailed Report on these schemes, I may
here mention the two methods which appear to me to produce the most
satisfactory results.
They are—
1st. The Septic Tank Process, or the Exeter process.
2nd. The Dibdin Process, or the Sutton Process.
In both processes bacterial agency is the important factor.
These microbes act on crude sewage, so that some liquify the solid
organic matter, and others act on it when liquified. Both these classe-.
of microbes exist in ordinary sewage, and whilst some act to advantage
when exposed freely to atmospheric oxygen, others do their work when
the atmospheric oxygen is rigidly excluded.
On these latter facts depends the working of the two processes I
have mentioned. At Exeter the sewage is allowed to fall into a sealed
tank, where the atmospheric oxygen is excluded, whilst in the Sutton
process the sewage is conducted through carefully prepared filter beds,
where the air is freely admitted.
In comparing the respective merits of these two interesting processes,
I may say that as a great deal depends on the local conditions,
such as the available fall of the sewage, and the nature of the soil, it
would be unfair to decide which was the better process unless a particular
locality was specifier!.
In the septic-tank process there is no sludge—an important point
from a financial aspect—the residue being merely a black sediment
of very slow formation.
Both processes are remarkable for their simplicity and economical
working, and after initial construction, the cost of which is much less
than that of constructing Precipitation Works such as we have at Leyton,
the working expenses are extremely small.