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complaints of bad smells near the Tolworth Police Station,
and many suggestions had been made as to the cause, and
various things tried as remedies, but in the end it was
ascertained that the culvert under the Ditton Road being at
a lower level had become foul. This was cleansed and
structurally altered, and is now no longer a nuisance.
The Sewage
Farm.
When the farm was taken over the effluent was exceedingly
bad and offensive, and the Thames Conservancy having
become aware of this, were taking action. Since then the
Surveyor has brought about a very considerable improvement,
but an improvement that cannot be considered likely
to be enduring until some further radical change in the
treatment and disposal at the works is made. Perhaps the
locality was the only one available, but at any rate it is far
from a suitable one in its present condition for the method
used. The most satisfactory land treatment of sewage is
that of Intermittent Downward Filtration—explained by the
term used—and is supposed to accommodate the sewage of
from three to five thousand persons per acre, according to
the efficiency of the chemical precipitation of solids and
subsequent filtration, but this requires a sufficiency of
thoroughly porous soil properly underdrained. Broad
Irrigation means "the distribution of sewage over a large
"surface of ordinary agricultural ground having in view a
"maximum growth of vegetation (consistently with due
"purification) for the amount of sewage supplied." Neither
of these two processes are capable of being adopted in their
entirety at Tolworth, owing to the soil not being of a
sufficiently porous character and for other reasons, so the
system made use of is that of Filtration which is "the
"concentration—after precipitation and chemical treat"ment—of
sewage at short intervals on an area of
"specially chosen ground as small as will absorb and
"cleanse it, not excluding vegetation, but making the
" produce of secondary importance."