MEMO REGARDING SLUDGE /AERATION TANKS APRIL 1978
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. L. J. DILL ARC, .JR., P.E.
. WILLIAM C. DUKE
. A. J. BIRCHALL, P.E.
. STEVEN E. THAYER, P.E.
. RICHARO B. GASSETT, p,E.
. W. E_ STRANG, ..JR.
July 24, 1978
. FEASIBILITY
. PLANNINQ
. REPORTS
. LABORATORY
. CONSULTATION
. OESIGlN
. INSPECTION
. RESEARCH
. HARRY E. WILD, JR., P.E.
. JOHN F. PENNIS. p.E.
!B'l.llE.!:JI C'Wlld 5- dl-HoclatE.~
CONSUL-TING ENGINEERS AND PL-ANNERS
ORMOND BEACH - CL-EARWATER
FL-ORIDA
WHEN REPLYING PLEASE ADDRESS:
40e BOUTH PROSPECT AVENUE
CLEARWATER, FLORIDA :!I3151S
813/442.71_
Mr. Anthony L. Shoemaker
Ci ty Man ager
City Hall
Clearwater, Florida 33516
Attention: Mr. Max G. Battle
Dear Mr. Shoemaker:
Re: Clearwater East Wastewater
Treatment Faci lity
Per your request, we have reviewed the operation of the East treatment faci tity
with regard to capacity and treatment performance since the insta Ilation of the
sludge thi ckener with regard to lifting the moratorium imposed on connections to
this plant in May, 1978.
The sludge floatation thickener was put into operation in mid-April, 1978, which
a II owed the four aeration tanks whi ch had been used as aerobi c digesters on an
interim basis since 1974,' to be uti Ii zed as aeration tanks in the wastewater treat-
ment process. These tanks were placed in service at the end of April, 1978.
Expansion of this treatment faci lity commenced in 1973, and was designed to
increase the plant capacity to 4.0 mgd. After the passage of the State law requiring
advanced wastewater treatment before discharge to Tampa Bay, additiona I primary
and fina I sedimentation tanks were added to the project by change order to provide
capacity for an average flow of 5.0 mgd to take care of the growth of the City unti I
such time as plans coo Id be implemented to provide the treatment required by State
law. However, we recommended to the City (letter of September 25, 1973) that
when the plant approached design capacity, chemical settling aids should be added
at the final stage of sedimentation in order to obtain the required treatment levels
since space limitations at the site precluded constructing the number of settling
tanks which would normally be provided for a treatment plant with an average capacity
of 5.0 mgd. In Apri I 1978, the City, with their own forces, insta lied a temporary
system to add alum to the treatment process and the system was placed in operation
in mid-May, 1978.
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Mr. Anthony L. Shoemaker
July 24, 1978
Page 2
During the month of June the treatment remova Is were 90% and 91% for B. O. D. and
suspended solids, respectively. Removals for the first half of July, with approximately
the same flow as the month of June, have averaged 94% for both B. O. D. and suspended
solids. The treatment system is still in the process of stabilizing and the City is
experimenting with various polymer floatation ajds for use with the sludge thi ckening
system. It shoo Id be noted however, that the average flows for the month of June and
the first half of July averaged 4.2 mgd, whereas the annual average flow to the plant
for the months of July 1977 through June 1978 was 4.68 mgd. Some flows which
previously were treated at the East plant were diverted by gravity to Marshall Street
in Apri I 1978. This reduction wi II be reflected in the future annua I averages.
In our opinion, there is some additional capacity remaining at the East treatment faci lity,
however, we recommend that the limited moratorium remain in effect for at least another
two months in order to determine the effect of higher flows which the plant will experience
during wet weather. However, plans for projects connecting to the East plant whi ch
were approved by DER and submitted to the City prior to the limited moratorium can
be approved at the City's discreti on and wi II not have an adverse affect on plant
performance. We a Iso recommend that the City provide a permanent system for the
addition of alum to the treatment process. This can be done at small cost utilizing
an existing concrete tank at the plant and will require only the purchase of a chemical
pump and plastic piping.
Very tru Iy yours,
BRILEY, WILD & ASSOCIATES
CONSU LTING ENGINEERS
JFD :hs
~. M. J. Paroby
Mr. Max G. B>:lttle
Mr. Pau I R. Rettig
Mr. F. J. Janocha
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0"" F. Dennis, P.E.
cc:
BRilEY, WilD & ASSOCIATES