sludge drying bed spec 6/2/1984� a
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DEAN BOYER. P. E.
CITY ENGINEER
Mr. Dennis Clovis
Salina Sand Company
P.O. Box 206
Salina, Kansas 67402-0206
Re: Filter Sand
Dear Sir:
ENGINEERING DEPARTMENT
300 WEST ASH STREET
P. 0. BOX 748
SALINA. KANSAS 87401
AREA CODE 913 827-9481
June 2, 1984
DONALD E. HOFF, P. E.
ASST. CITY ENGINEER
D. W. BASSETT
TRAFFIC ENGINEER
The Kansas Department of Health & Environment has a specification
for filter sand to be used in sludge drying beds. This specification is
stated below:
"The sand shall have an effective size ranging from 0.5 to 0.8 mm
and a uniformity coefficient of less than 5."
The terms, "effective size" and "uniformity coefficient" are defined
as follows:
Effective Size -.(a) the size of particle which is exceeded in
fineness by 0% of the sample or (b) the diameter of the largest
grain among the smallest grains making up 10%, by weight, of a
sample.
Uniformity Coefficient - (a) the ratio of the 60% size to the
effective size or (b).the ratio of the effective size to the
diameter of the largest grain among the smallest grains making
up 60%, by weight, of the sample.
Apparently, no specification for the filter sand exists which utilizes
a gradation requirement based solely on sieve analysis. The definitions of
"effective size" and "uniformity coefficient" seem vague to me but I hope
they are useful to you.
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Sincerely,
.. a
Don Hoff, P.E.
MEMBER ... KANSAS LEAGUE OF MUNICIPALITIES, NATIONAL LEAGUE OF CITIES