Every evening, Wilmington daily commercial., 1906-02-06
WATER FILTRATION.
A Paper on the Subject Read by Chief
Leisen Of the Department.

A Paper on the Subject Read by Chief |
Leisen Of the Department.
Theodore A. Lessen, chief engineer of |
the Water Department, read a lengthy
report, at the meeting of the Board of
Water Commissioners, yesterday after
noon, dealing with slow sand and me-
chanical filtration. Mr. Lessen recon-
mending the slow sand method for VIII
mington. II is reported that the slow
sand method has practically been agreed
upon by the Water Commissioners for
the new water system, now under con-
struction. The report of the chief engi-
neer was ordered spread upon the
minutes of the board and incorporated
in the annual report.
The argument of the chief engineer
was that Brandywine water can best be
treated by the slow sand method.
Ia his report Chief Engineer Leisen
states that while each different water
supply requires certain individual inves-
legations to determine the treatment
best adapted TO its peculiar condition, it
IS not at all necessary to inaugurate a
thorough and systematic course of ex-
perimentation in each case" He also
states that I'm the application of this
principle to our own conditions it is pos
sibe to utilize the results of the expert.
mental work carried on BY other munich
palities on waters closely analogous to
that of the Brandywine, and, if not mis-
led by the efforts of prejudice, CONNER
cial interests, or masked antagonism, nor
unduly influenced by the persuasive elo-
quence Of certain advocates TO promote
their own peculiar systems or products
we should take advantage of the infor-
nation abducted Information to obtain
which thousands of dollars have been ex-
pended by other cities-and arrive at a
determination of the method best suited
to our case with reasonable degree of
certainty that no mistake is being
made"
The chief engineer claims that sand
filtration is best suited for waters high
in sewage pollution and low i'm turbidity,
while the mechanical system is best suit
ed for waters which contain little sew
age pollution, but are high in turbidity.
In the report is given n review Of the
Investigations made in Pittsburg, Phila
delphia and Washington, with opinions
from such experts as Allen Hazen, Ru-
dolp Herring, George W. Fuller. Samuel
NJ. Gray, Col A. NJ. Miller and John W.
tions
These Investigations resulted in sand
filtration being adopted by the three
cities, and in his report Chief Engineer
Leisen denies that the system in Wash
lngton, ID. G.. is not giving satisfaction
as was recently claimed
In speaking of these investigations the
chief engineer makes the contention that
the natural conditions of Wilmington
are more favorable for slow sand filtra-
tion than at Washington or Pittsburg.
and are similar to those at Philadelphia
and Albany. BY the facilities for stor-
age, which are contemplated under our
plans, the actual conditions will be even
better than in the last mentioned cities
BY stopping all pumpage for periods of
from one TO three days we will be able
to utilize the water al an average ttrb-
idity of 25 to 80 parts per million. and
a maximum turhidity which will seldom.
if ever, exceed 100. With these CON
ditions prevailing it is obvious that
slow sand filtration would fulfill every
requirement., IN manner superior to
any other system
Another phase of the situation that
is favorable to slow sand filtration. is
the possession 10y this city of large
tract of land admirably suited to the de-
velopment of plant capable of treating
fifty million gallons daily, feature
which eliminates the item of expense
for land, from any comparison of cost
between the two systems"
Chief Engineer leisen holds that the
crucial test to the mechanical filter, and
the one under which it is most likely TO
fail is the test of reliability.
I'm conclusion the chief engineer de.
clares that there is no disposition to de-
cry the merits of mechanical filtration
as a system. He says "ln many in
stances it will perform its work as well
as slow sand filters, in some it NAV do
better; but it is absurd to push its
claims in every case regardless OF con.
ditions"