Seminar On Phosphorous Removal May 1-2, 1968 Chicago, Illinois


                            SEMINAR Oil  PHOSPHORUS  REl'.QVAL
                                    M*\Y 1-2   1 QS°
                         WALDORF  R00;i —  COIIP.AD  HILTO;:  MOTEL
                                  CHICAGO,  ILLINOIS
May_J_

 9:30 a.m.
               l.felcome & Introductory Remarks
               Enforcer:2nt Co:: ference Recommendations
               Seminar Objectives
Speaker

H. U. Poston
M. Stein
Dr. L. W. Weir.beroer
                                .1st TECHNICAL SESSION
                            Moderator - Dr. D. G. Stenhan

10:00 a.m.      Forms in Measurement of Phosphorus
10:30 a.m.      Present & Projected Phosphorus Removal
                 in Conventional Treatment
11:15 a.m.      Break Period
11:30 a.m.      Phosphorus Removal by Mineral Additions
                 to Primary - Secondary Processes
12:15 p.m.      Lunch
                                                                Dr.  R.  B.  Dean

                                                                Dr.  R.  L.  Bunch


                                                                E.  F.  Barth
                               . 2nd TED:;ITCAL  SESSIO;;
                             Moderator  -  F. !!. Middleton

 2:00 p.m.     Phosphorus RemovrJ by Tertiary
                 Treatment v/ith.Lime &  Alum
 2:45 p.i,!.     Reuse & Disposal of Lime Sludges
 3:30 p.PI.     Bret!. Period
 3:45 p.m.     Handling Recovery ? Disposal oT
                 Alum Sludocs
                                                                Dr.  C.  A.  Brunner
                                                                Dr.  R.  B.  Dean
                                                                Dr.'J.  C.  Fai
May 2
 9:00 a.m.
 9:45 a.m.

10:30 a.m.
10:45 a.m.
11:30 a.m.
12:00 noon
12:15 p.m.
                                3rd TEci-r;ica SESSIO:;
                             Moderator - A. C. Print/:, Jr

               Alternative [Methods for Piiosn!-,oi'us Removal
               Project Costs for Phosphorus Removal
                 & Sludge Disposal
               Break Period
               Removal of Nitrogen from V.'aste 1,'aters
                 Part I  - Biological
                 Part II - Physical-Chemical
J. K. Cohen

R. Smith
                                                                E.  F.  Berth
                                                                Dr.  0.  B.  Parrel!
               FHPCA - Supported Phosphorus Removal Projects    Dr.  D.  G.  Steohan
               Announcements
               Closing Re;;;arks
Dr. 0. I. Brecman
H. W. Poston

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AGENCf

Forms and Measurements of Phosphorus B« B. Dear
%

Phosphoric Anhydride , ,Pk°10 (usua-Hy calculated as Po0^)

Orthor>host>hates Found in Water '
Phosphoric acid ^^k telow PH 2.2 ' >"» %

Dihydrogen phosphate ion (nonovalent) H PO, ~ from pH 2.2 to 7«2

Monohydrogen phosphor inn (divalent) HPO^~ from pH 7«2 to 12.i

Phosphate ion (trivalent) ^k~ ^osva pH 12.4 ->...'.,,

Dicalcium pliosphate CaHPO^ from pH 6 to 8 -,

(Tricalcia-i phosphate, Ca (PO, )p, does not form in var.er)

Hydroxyapatite Ca OH(PO. ). above pH 7-8

Fluorapatite Ca F(?0, )„ above pH 7 -•

/J.uninuni hydroxide adsorbs K?0, ~ from pH 5 to 10

Alumina^e ion Al(OH)," forms above pH 10 . -JA ,._/. -^., ,..-.„,, z ;.--r -

Ferric hydroxide adsorb.- :"-?0. ~ above pH 4

Magnesium hydroxide flocculates colloidal phosphates above pH 10-11

Pol'.Tjhosnhates - - , . , . - „-. '
All polyphospha-ces hyar ~/.yzc slowly to orthophosphates

Sodium Trimetaphosphate Na,(?0-,)-, — a ring compound

Sodium Polymetaphosphate (NaPO ) -- a long chain

(there is no justification for the name "hexanotaphosphate")

Godi'jr: Pyrophosphate Na. P?07

Sodium Tri Polyphosphate Na P 0

Organic Phosphates

Esters and anhydrides S?? ,<- ~P ROPO =, ROPO PO =

Phosphagens RMPO

Reference
(l) Van Wazer,
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n.

Forma and Measurements of Phosphorus R. B. Dean

Tentative FWPCA Definitions for Phosphorus Forms in Water

All expressed as mg/1 of P

I. P, Soluble (filterable) A + B + C

II. P, Total B + C

HI. P, Soluble, Ortho A + C

IV. P, Total, Ortho (see C below) C

Methods for Determining Forms of P

A. Soluble: Filter through 0.^5 micron (bacteriological) membrane filter.

Soluble or filterable phosphorus consists of truly soluble
ions, colloidal precipitates of insoluble phosphates,
fragments of cells and organic and inorganic phosphates
(and polyphosphates) adsorbed on natural colloids.

"' .~~__, Insoluble phosphorus equals Total minus Soluble and consists
* „'• —--"^.'of phosphorus in cells and multicellular matter together
--'---•--_,•, with clay and other minerals carrying adsorbed phosphates.

B. Total: Convert to Ortho by digestion with acid, and persulfate.
M. E. Gales, Jr., E. C. Julian and R. C. Kroner, JAWWA 58(10),
1363-8 (1566). —

Digestion converts all polyphosphates and organic phosphates
to orthophosphoric acid and destroys organic turbidity and
color.

Acid hydrolysis liberates most inorganic phosphates and some
organic phosphates.

C. Ortho: Mixed reagent test using ascorbic acid.
J. Murphy and J. Riley, Anal. Chem. Acta. 2J, 31 (1962).

or perhaps Stannous Chloride Method, Standard Methods for the
Examination of Water and Wastewater, 12th edition (1965) in
fresh water samples.

Phosphoric acid is converted to phosphomolybdic acid and
reduced to a blue color. Corrections must be made for color
and turbidity of the sample when determining P, Total, Ortho. (IV)
May 1, 1968
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Ill

Forms and Measurements of Phosphorus R. B. Dean

Conversion Factors

In water analyses all neasurenents should be reported as mg/1 of P.

To convert X to P X To convert P to X
Multiply by: Multiply by:

..327 po^ '"3.06

.316 H^POk 3>l6

.200 Ca (PO, ) 5.>00

.181 Ca OH(PO,)_ 5.51
May 1, 1968
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SEMINAR ON PHOSPHORUS REMOVAL
CHICAGO, ILLINOIS
MAY 1 AND 2, 1958

REMOVAL OF PHOSPHATE FROM MUNICIPAL SECONDARY EFFLUENT
3Y LIME TREATMENT

Carl A. Brunner
A 75-gpn lime treating pilot plant is being operated at the Lebanon,
Ohio Sewage Treatment Plant for clarification of secondary effluent. During
operation of the pilot system, data have been obtained on removal of phos-
phate both in the clarifier and on the filters following the clerifier.

The clarifier is a single-stage; upflow unit with internal recircu-
lation of sludge. This equipment is shown in Figure 1. The ap.fiov rate
in the settling section of the unit is 1 gptn/ft . Detention time Lv. the
clarifier is 110 minutes. High-calcium bydrated line is used fcr clarifi-
cation. It is added as a slurry at a rate sufficient to maintain a pre-
determined pH in the clarifier. The slurry contacts incoming secondary
effluent in the mixing zone. The mixture then flows into the flocculation
zone. Water is moved up through the mixing -zone at a high enough rate to
draw some of the sludge off the bottom of the clarifier into that zone and
out into the flocculating zone. The purpose of the sludge recirculation is
to increase sludge particle size and to hasten precipitation of calcium
carbonate and other inorganic materials. The water flows downward in the
flocculating zone and either enters the settler or returns to the mixing
zone. Sludge deposits on the botcoa of the clarifier ana is moved by
tangential pulses of water to the collection ring. The water pulse system
is not shown in Figure 1. It is possible tc concentrate the sludge to 10
percent solids in the ^lariiiar, hic clogging problems nay result. Usually,
the sludge is removed as a 2 or 3-percent slurry and is gravity thickened
to 10 percent solids in a separate vessel.

Following the clarifier are two dual-media filters that operate in
parallel. The media bads consist of 6 in. of G.46--m sand overlaid vith
18 in. of 0.75-ran anthracite coal, Water rate through the filters is
2 gpm/ft . Filters are backwashed when the pressure drop exceeds 7 in. Hg.
Filter runs usually exceed 43 hrs and are often much longer.

The secondary effluent that is being lime clarified is a hard water
with high alkalinity and high ionic strength. When there is no storm-water
dilution of the sewage, the calcium content is about 100 mg/1 as Ca,
magnesium content is about 30 mg/1 as Mg, and alkalinity is about 400 mg/1
as CaCO^. Lime treatment of this water gives a rapidly-settling sludge.
The amount of insoluble material that is carried out of the settler is
small, averaging about 15 mg/'l. This material is largely calcium carbonate.
It is effectively removed by the dual-media filters.
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- 2 -
Phosphate removal in the clarifier alone and over the whole clarifi-
cation system has been determined as a function of clarifier pH. These
results are shown in Figures 2 and 3. The average phosphate concentration
of the secondary effluent during this study was 30 mg/1 as P0». Phosphate
removal improves as operating pH is increased. This effect is most clearly
shown when the water has been filtered. (It is not intended to discuss
here the forms in which the residual phosphate may exist. Because of the
very low turbidity of the filtered water, however, it appears that the
phosphate is in true solution.) The data in Figure 3 give a good indica-
tion of the degree of phosphate removal that can be obtained by clarifica-
tion of a hard, high alkalinity water using single-stage treatment. An
average phosphate concentration of less than 1 mg/1 is obtainable at a pH
of 10. For this particular water, 90-percent phosphate removal is obtain-
able down to a pH of 9.5. Eighty-percent removal occurs at a pH of about
9.0.

Where phosphate removal is the primary purpose of lime treatment,
elimination of filtration would be desirable because of the resulting cost
savings. The residual phosphate concentration would be expected to in-
crease because of the presence of phosphate-containing suspended solids.
The data of Figure 2 show, however, that good phosphate removal is still
possible. Ninety-percent removal is generally obtainable down to a pH of
9.7; 80-percent removal down to slightly lower pH. If improved removal
were required, a lower rate of rise could be used in the settler. This
would decrease the carry-over of suspended solids and any phosphate con-
tained in these solids. The cost of a larger settler would be substan-
tially less than the cost of filters,

An important factor in the economics of lime treatment is the amount
of lime required. Lime dcse depends upon the mineral composition of the
water. One of che most important components is the alkalinity. The clari-
fier pH is also important because the reactions that occur during lime
treatment are pH dependent. Table 1 gives lime doses that were measured
for a range of alkalinities and pH values. Because other constituents in
wastewater may have a significant effect on lime dose, the values in Table
1 must be considered very approximate. The importance of alkalinity on
dose is obvious, however. For the Lebanon plant it is estimated that an
annual average of about 250 mg/1 of hydrated lime would be required to
obtain 80-percent removal of phosphate. A lower lime requirement is
likely at many plants because of lower alkalinity.
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LIME
SECONDARY EFFLUENT
75 gpm
CLARIFIER
PRODUCT
SETTLER

MIXING ZONE
FLOCCULATING ZONE
SLUDGE
COLLECTING
RING
FIGURE I. LIMECLARFIER
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8
O
O
~y *"

§5 4
O*
CL
cn
O
X
Q.
8.5
9.5
• *• •*
•*•*
10.0
CLARIFIER pH
10.5
11.0
11.5
FIGURE 2. EFFECT OF pH ON PHOSPHATE CONCENTRATION OF

EFFLUENT FROM LIME CLARIRER
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CL
8.5
9.0
9.5 10.0

CLARIFIER pH
IQ5
11.0
11.5
FIGURE 3. EFFECT OF pH ON PHOSPHATE CONCENTRATION OF

EFFLUENT FROM FILTERS FOLLOWING

LIME CLARIFIER
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TABLE I. LIME REQUIREMENTS
FEED WATER
ALKALINITY
Ong/1 csCoCOJ
• 300
300
. 400
400
CLARIFIER pH
o
9.5
10.5
9.5
105
APPROXIMATE LIME
DOSE
(mg/l of GotCH^)
200
350
300
500
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MINERAL CONTROLLED PHOSPHORUS REMOVAL*

E. F. Earth and M. B. Ettinger, Research Chemists,
Federal Water Pollution Control Administration,
Cincinnati Research Laboratory, Cincinnati, Ohio
When considering the removal of phosphorus by biological treatment processes,
it becomes evident that the cycle of phosphorus in a biological system is different
from the usual wastewater components such as carbon and nitrogen. Tnis is il-
lustrated in Table I. Phosphorus removal is probably a combination of cellular
growth and inorganic solubility products. Tnis may account for the wide variation
in phosphorus removals reported from various municipal treatment plants. The
mineral composition of the wastewaters or characteristic industrial wastes may
influence the phosphorus removal.

Many investigators have studied the problem of phosphorus removal. Figure 1
indicates some of the approaches. It will be noted that the approaches can be di-
vided into two groups. One group attempts control by biological means; the other
group adjusts the mineral composition of the biological effluent to precipitate phos-
phorus.

Our approach to the problem was to blend a chemical precipitation with ths
active biological solids. We did this by introducing, directly into the aeration
chamber, mineral salts that were known to form slightly soluble phosphorus
compounds. The work was done on a 100-gallon-per-day continuous flow pilot
plant, operated as conventional activated sludge.

The mineral addition tried and the phosphorus removals obtained are given
in Table II. During the periods when iron ana aluminum were added to the aerator,
turbid effluents were obtained. The pH in the aerator dropped to about 6. 2
because of hydrolysis of the metal salt producing three hydrogen ions for each
ion of metal added. This was corrected, as shown in the last entry in Table II,
by introducing calcium with the aluminum to control pH.

In order to reduce the extraneous sulfate, chloride, or calcium ions intro-
duced with this approach to phosphorus removal, it was decided to investigate
the use of sodium' aluminate. This material will introduce only a small extra-
neous increment of sodium and will automatically compensate for pH control in
*A more complete publication will appear in the Journal of the Water Pollution Control Federation.
1-32
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1-33
*
the aerator. Excess hydroxyl ions will be converted to bicarbonate by the carbon
dioxide produced during aeration. • '

Table III gives the efficiency of phosphorus removal when introducing sodium
aluminate directly to the aerator. The amounts of aluminum and phosphorus were
varied to determine the dosage necessary for good removal. It can be seen from
Table III that when the aluminum-phosphorus ratio is about 1:1 good removals are
obtained.

At this point in our studies we cannot define the relative contribution of simple
chemical precipitation or sorptive properties of the activated sludge mass to overall
phosphorus removal. The dosage of precipitant needed is much less than that needed
for a separate unit operation without biological solids. This indicates that the large
surface area of the biological floe is helpful.

The aluminum does not in any way interfere with biological nitrification or
carbon or solids removal.

The sludge produced by the mineral supplement and the microbial floe are
intimately associated and the existing final settler serves as the liquid-solids
separation device, saving an additional unit operation. The mixed sludge produced .
has better settling characteristics than either a biological sludge or aluminum.
hydroxide floe alone.
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1-34
TABLE I

Difference Between Phosphorus and Other Wastewater

Components During Biological Treatment

Materials that can show a net loss through treatment.

Not conserved in process streams.

Aerobic Anaerobic

BOD ) •
COD / C'H C02'H2° CH4H2.' C°2
0
Nitrogen N02,N03>NH3 NH3,N2

Sulfur S04 H2S,S

Solids All above All above
Phosphorus is conserved. No net loss through treatment,

should be able to account for every bit of phosphorus in

process streams. Phosphorus.enters in highest oxidized

form, no common biological systems reduce phosphate.

Aerobic Anaerobic
Phosphorus Organic P z—- Inorganic P Organic P *——• Inorganic P

Phosphorus removal is probably a combination of cellular growth and

inorganic solubility.
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1-35
TABLE II

Results of Screening for Mineral Supplement
to Activated Sludge Process
Direct Dosage to Aerator
No Supernatant Recycle, No Primary Settling
Mineral Addition | Introduced as
None (base line)
Ca, 150 mg/1
Ca, 150 mg/1
plus
F, 6 mg/1
-Mg, 20 mg/1
Fe, 15 mg/1
Al, 20 mg/1
Al, 30 mg/1
plus
Ca, 20 mg/1
-
CaO
CaO
NaF
MgS04
FeCl3
A12(S04)3
A12(S04)3
CaO
To Form
-
Hydroxyapatite •
Apatite
MgNH4P04
FePO.
4
A1PO.
4
A1PO,
<*
Overall Removal
407.
647.
757.
507.
757.*
707.*
90%
* Turbid effluents
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TABLE III
1-36
Relation of Aluminum to Phosphorus
Direct Dosage of NaAl(OH) to Aerator
Al+3, mg/1
5
5
. 10
10
Influent
Phosphorus, ng/1
3
8
13
10
Effluent
Phosphorus, mg/1
0.2
2.2
- 1.3
0.2
Percent Removal
(mass balance)
94
75
90
98
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• PHOSPHORUS REMOVAL IN CONVENTIONAL TREATMENT

Robert L. Bunch

TREATMENT CLASSIFICATION BY POPULATION FOR YEAR 1962 '
______ ___ _____

Population treatment treated of total

X
6
10
6
10
6
10
6
10

Primary- intermediate

Activated sludge

Trickling filter

6
TREATMENT CLASSIFICATION BY FACILITIES FOR YEAR 1962
Number Type % of total

11,655 Total 100
2,277 Raw discharge 19.5
9,378 Treated discharge 80.5
2,794 Primary-intermediate 24.0
6,584 Secondary 56.5
800 Activated sludge 7.0
(12% of secondary)
3,506 Trickling filters . 30.0
(537o of secondary)
1,348 Stabilization ponds 12.0
(20% of secondary)
DRAINAGE BASIX WASTE DISTRIBUIION FOR YEAR 1962

Basin % of total discharge
Raw Treated

Lake Erie 23.6 74.4
Upper Mississippi 12.3 87.7
Western Great Lakes 7.8 92.2
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*
PHOSPHATE REPORTING
Today's investigators in sanitary engineering express the results
of phosphorus analysis as P (phosphorus) and not as PO, (phosphate) and
P 0 (phosphorus pentoxide). The relationship between various methods
of expression are:
1/mg/l P - 2.29 mg/1 P20 = 3.06 mg/1 P04
1 mg/1 PO = 0.75 mg/1 P^ = 0.33 mg/1 P
1 mg/1 P 0 =1.34 mg/1 PO = 0.44 mg/1 P
z. JD Q
DIGESTER RECYCLE
Normal digester operation calls for recycling the supernatant
from the digester into the influent line of the waste treatment plant.
This procedure adds a heavy load of soluble phosphates as approximately
807=, of the phosphates present in sludge are solubilized during digestion.
A sizable reduction in effluent phosphate level can be realized by
eliminating this addition. Wasted sludge is the only way phosphates can
be removed in a purely biological process. It'cannot be emphasized
enough that regardless of the complex internal mechanic::; of phosphate
removal (precipitation, adsorption, etc.) the actual phosphorus removal
that a plant can achieve will ultimately depend upon the arount of sludge
wasted. If digester supernatant is returned to the treatment plant, the
only phosphorus renoved will be that associated with the digested sludge.

PHOSPHATE REMOVAL BY VJASTEWATEP, TREATMENT PLANTS
Type • % removal
Primary sedimentation 5-15
Extended aeration (sludge wasting) 8-15
Trickling filter 20-30
Activated sludge 30-50
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*
ENHANCING PHOSPHATE REMOVAL

The most economical and desirable method of increasing phosphate

removal v;ould be to induce a high degree of phosphate uptake by activated

sludge. The literature indicates that several factors exert an influence

on phosphate removal. The most commonly considered variables are:

1. Aeration time and rate of air supply.

The rate of aeration and the aeration time have been indicated by

most investigators as the most important criteria. The rate of air

supply probably being the more critical of the two. Aeration rates in

the order of 3 to 7 cfm/gal and detention times of 4 to 6 hours appear

to be desirable.

2. Concentration ^of mixed liquor susBended solids.

There is some disagreement in the literature v:ith respect to the

optimum concentration of mixed liquor suspended solids (>ILSS). Apparently,

increased uptake has been attained at both low and high MLSS. It would

appear desirable to investigate a rather broad range of solids in future

3. Concentration of dissolvej. oxygen in aerator .

Where increased phosphate removals have been experienced, they did

not occur until 1.5 to 2.0 mg/1 DO had been attained. It seems essential

that at least a DO level of 2 mg/1 be maintained in t?ie last half of the

aeration tank to insure that solids retain phosphate enrichment through

secondary clarifiers.

4. Time of sludge retention in secondary clarifier.

Phosphate uptake by sludge organisms in the absence of growth

leaks out when the dissolved oxygen level falls. Leakage will occur in
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_ 4 -
the secondary settling tank when the sludge consumes available dissolved

oxygen. It has been suggested that solids detention time in final

clarifiers should be less than 30 minutes. If rapid sludge withdrawal

is important, we should design a more efficient and rapid method of

separating solids from liquids.
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SH.iEI.AE Oil EI03PIIORJS REMOVAL
CHICAGO, ILLINOIS
Kay 1 and 2, 1953

HI03KIORUS r.Z:CVAL BY TERTIARY TPZATh
WITH LI; 3 Ai:D ALUM

C. A. Brurr.ier
I. Lime Treateenb of Secondary Affluent

A. Removal is probably by formation of insoluble ccr.pou.nds containing
calciuu and phosphate su.cb as h.ydro;ryap-;>.tite.

B. Equiprent is the s::.rr.3 as that used, for lir.-;e softening of vater. Up-
flov cl'.'.rifiers vith recycle of slv.o^e to the flocculating zone vorlc
well. Single-ste^e equipment; i.e., equipment &llo"ir>3 operation
at only o^e ^3., Qivcz 30od phosphate rer'ovr.l. T.'o-sto^e ecuipnent,
i.e., ecuipr.snt allovinj; opsrr.tiori r.t one pIT follo-.rc-d by operc.tio:'1.
at a lover pTI is presently beir_3 tested. Phosxh-r.te rer.iov-. 1 should
be excellent. A tvo-st^e sys to': is inherently r:ore co:::plic;;,tod
tho,n the sin^le-ste^e sy^-tc.' end r.:.y hrvc sijriificc-.ntly higher c;-.pital
cost.

Filtrc.tion follovlr.3 settling iriprovas phosph-te re'-.ovc.l. Good re":o^.r.
can be cb'coined, ho'ever, vithcut the ui'e of filters.
led^e of the co-ice.:trc.ti:"£ of other :.v,teri?J.3 ir. the.vch-cr, eppeci-:lly
bic^rbono,te rlho.linity. If the pho"p:r;te is re-.ovei'as hyc!j.-o.\y._.r.3.tits,
only about 3-0 i:^ts by re:*-3at of Cr.C e.rs required per p^rt of phos-
phon-f. Thet e,.:ov.it of lire ccn-titvoes only c. rinor frrcticn of tre
too-..! viv.:.jly rccydrod for tve r.v.:i',i-ouo r:::.c!:ion.-. th?t cccrr; c^rinj
Bcperi rental results inkier to rhoapbcte re"io\ral irroro >.'o:, vith iririrea.".:
p!I. For single-otc-o tro-tr.:nt, a'clarifier pT' o^ abo^t 9.5 h:~ been
found to p;v.e 63-pereeno re..ov-.l of Dhezrjhate in one pilot svv "y -,-ith
. Th:- c.verc;;-; Ir.-.e dose for thrt cL^d;- i" cetiv:
c.t 250 rj/l as Cc (0

D. The p:I of lino treated -.-o,ter is 3-ihely to be too hi3h fo?- direct dis-
char3e. Recs.rbonation vill be necessary in these coses.

B. The sludge forced during treatment of a hi3h ar'to.linity -.rater is granular
and of his'n density. It consists largely of calciiU: c-arbone.te. Solids
concentrations in the sludge of r.ore thc-n 10 percent can be obtained.
Settling is rapid and can be improved by recycle of part of the sludge
to the flocculatir>3 zone of the clarifier. Overflow rates of I'iGO
god/sc ft have been sho-.T. to bo satisfactory for good phosphate renovol
without usir-3 filtration.
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-2-
The sludge fron raters of low nineral content Is rnore flocculent and
may not settle well especially if there is appreciable suspended.
material left in the vastevater after biological treatment. Experi-
mental vork with this type of ', ater has shc"n that addition of sodium
carbonate or sons other for,." cf alkalinity r:ay be necessary to" increase
floe density. Iron salts also iv.prove operation. Settler overflow
rates vill be lower than for the highly r.ir.eralized. waters. A study
is being naoe to deteri.vinc r.etheds for iraprovu'ng 3rirr.e treatnent of low-
mineral-content '.raters.

F. For large p3.axi.ts treating high alkalinity water, calcination appears
most appropriate for sludge disposal. Usable lir.e is recovered in the
process.

II. Aluvi Treatment of Secondary Effluent

A. Fnosphate rer.oval is either by incorporation in a cc::p3.ex along with
aluuin!1:: and hydroi-iyj. groups or by adsorption on &lurri~nun hyde;'oxide floe.

B. Equip-.-..-nt should be the se.rv as that used for'aluv; clarification. Pilot
work has shown a horizontal fjoeeulator-srcbler arrangement to be satis-
'factory. Use of filters after the settler will give Improved phosphate
removal, but these should not be necessary to achieve 80-percent renc-val.
C. Alu-'i dose is difficult to predict at present. The ir.iniriur.i the.t appears
necessery is tro p:r'os of cluvl^-j'.1. by veight per p;-rt of phosphorus.
For very high degree? of rhcschet-j roi: ov;-1 the ra'tio is. four cr nore.
For nu.nlcip:'! secer';-ry effluent the required, dose of torr^.erclal alur:
is likely to be 200 rg/1 or nore for 80-percent'phosphate rcr.ovel.
D. The p!i or
treo.t-.'-,rt vithor;, ;.djuet -:.rt. The cdditirn of
If the .v.ter cou'..ains enough a,l":-, Unity, the chrnge '.'ill be rrlr.er. If
there is nob er.TJgh eTialinity tc buffer the rr.ter, raiding cf the p7
cay be desirable before dlsep-ige. Ore "ay to cveree-e Ir.rge changes
in pTI is to supply pa:: t of tils air. ilna.i In the foru of sodri.iL: £.lv..:l:.et
E'^reri1 :er.tr,l ~:o:cv: has sl:^"/n a CO' 'bioatior. of rlu\: rrd so'Jiu:1. ali'~:i"-::te
E. The slu.fge fonied is volujiinuiis and of 3.o-.7 deiiai/b^v /.As, a result,
settler overflow rates as lo-; es YCD gpd/sq^fu 'Jay be neciess-ery in the
absence of filtration to prevent er.cesslve floe carry-over in the treated
vater. Addition of otber chemicals such as activated silica :.".ay be
required to i'lprove settlirg. Since large volv~.es of sludge are pro-
duced sludge handling presents problems.

F. The economics of alu;n treatrent vould be improved if the alur.iinuun could
be recovered and. reused. Both cher.:icc,l costs and sludge disposal costs
would be decreased. Althoxrgh several sche;:.es hare been investigated for
alnr.rinuv. recovery, none have yet been found to be practical.
-------
fleuse, Recycle and Disposal of Lima Sludges R. B. Dean
Selected References from:

Mulbarger, M. C., Grossman III, £., and. Dean, R. B.
"Lir.e Clarification, Recovery and Reuse for Wastewater Treatment"
Prepared for WPCF Annual Meeting, Chicago, October 1968.

BIF Bulletin No. 1, "Lime - Handling, Storage, and Use in Water and
Wastevater Treatment," pp. 21-24, Providence, Rhode Island (1962).

Black, A. P., "Disposal of Softening Plant Wastes - Line ar.a Line-Soda
Sludge Disposal." Jour. American Water Works Association, 4_1, 9> 319
(19^9).

Black, A. P., and Eidsness, F. A., "Carbonation of Water Softening
Plant Sludge." Jour. .American Water Works Association, _^9_, 13^3 (1957)*

Buszell, J. C., and Sawyer, C. IT., "Removal of Algal 1,'utrien-c from
Raw Wastevater with Lime." Jour. Water Pollution Control Federation,
_3_9_, Rl6 (October 1967).

Jackson, M. L., "Soil Chemical Analysis." Prentice-Kali, Inc.,
Englewood Cliffs, N. J. (i960).

Malhotra, S. K., Lee, G. F., and Rohlich, G. A., "Nutrient Removal
from Secondary Effluent by Alum Flocculation and Lime ?reci-iration."
Int. J. Air Water Poll., 8, 487 (1964).

Minneapolis City Council Water Department, "Investigation ~f Recovery
and Disposal of Solids from the Water Treatment Procesc." Sanitary
Engineering Report No. 127-5 (1959).

Kelson, F. G., "Recalcination of Water Softening Sludge." .:r —.
American Water Works Association, 36, 1178 (
Owen, R., "Removal of Phosphorus from Sewage Plant Effluent vitn Lime."
Sew, and Ind. Wastes, 2J5, 548 (1953).

Rand, M. C., and Nemerow, IT. L., "Removal of Algal Nutrients from
Domestic Wastewater." Report No. 9, Department of Civil Engineering,
Syracuse University Research Institute (1965).

Russell, G. D., and Russell, G. S., "The Disposal of Sludge from a
Lime-Soda Softening Plant as Industrial Waste." 9th Annual Industrial
Waste Conference, Purdue University, Lafayette, Indiana (May 10-12, 1954)

Slechta, A. F., and Gulp, G. L., "Water Reclamation Studies at the
South Tahoe Public Utility District." Jour. Water Pollution Control
Federation, £2, 5, 737 (May 1967).
May 1, 1968
-------
RECOVERY AI-TO DISPOSAL OF ALUM SLUDGSS
J. B. Farrell
Presented, at the

Conference on Removal of Phosphate
Ciaica^o, Illinois
May 1-2, 1968
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RECOVERY OF ALUM BY AN ACID-FREEZING PROCESS'.
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-------
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PHOSPHATE REMOVAL BY ALUM PRECIPITATION, WITH AL RECOVERY

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-------
LIST OF PERTINENT REFERENCES
1. Palin, A. T., Proc. Goc. Water Treatment and Examination, _3_, 131-147
(195*0, "The Treatment, and Disposal of Alum Sludge.'1

2. Doe, P. V/., J. Inst. >-/ater Engr., 12(6), ^409-^5 (1958), "The Treatment
and Disposal of ',/ashvater Sludge."

3. O'Brien & Gore, Res. Rept. No. 15, for N. Y. State Dept. of Health,
"Waste Alum Sludge Characteristics and Treatment," Dec. 1966.

if. Roberts, J. M., and Roddy, C. P., J.A.W.W.A. . J>2(7), 857-866 (i960),
"Recovery and Reuse or Alum Glud^c at Tampa."

5. Isaac, P. C. G. , and Vahidi, I., Proc. Soc. Water Treatnent and Examina-
tion., 10, 91-117 (1961)

6. Lea, W. L., Rohlich, G. A., and Katz, W. J., Scv. & Indus t. Wastes,
, 261-275 ( 195*0.
7- Slechta, A. F., and Culn, G. L., J. Water Poll. Control Fed., 39(5),
787-814 (1967).
-------
CHEMICAL-PHYSICAL METHODS FOR CON3ROL

AND REMOVAL OF NITOOGEN
J. B. Farrcll
Presented at the
Conference on Removal of Phosphate
Chicago, Illinois
May 1-2, 1968
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LIST OF PERTINENT REFERENCES

1. Slechta, A. P., and Gulp, G. L., J. Water Poll. Control Fed., 39(5),
787-8l4 (1967), "Water Reclamation Studies at the South Tahoe Public
Utility District."

2. Eliassen, R., and Bennett, G. E., J. Water Poll. Control Fed., 39(10),
(Part 2), R81-R90 (196?), "Anion Exchange and Filtration Techniques for
Wastewater Renovation."

3. Perry, R. H., Chilton, C. H., Kirkpatrick, S. D., "Chemical Engineers'
Handbook," 4th ed., McGraw Hill, N. Y. (1963).

4. Ames, L. L., Jr., "Zeolitic Removal of Ammonium Ions from Agricultural
and Other Wastewaters," in Proc. 13th Pacific Northwest Inaust. Waste
Conference, April 6-7, 1967, pub. by Tech. Extn. Services, Washington
State University, Pullman, Washington.

5. Farrell, J. B., Stem, G., and Dean, R. B., "Removal of Nitrogen from
Wastewaters," Internal FWPCA Report, Cincinnati Water Research Laboratory,
4676 Columbia Parkway, Cincinnati, Ohio, May 1968.
-------
MANAGING CONTINUOUS FLOW BIOLOGICAL DENITRIFICATION

E. F. Barth and M. B. Ettmger, Research Chemists,
Federal Water Pollution Control Administration,
Cincinnati Research Laboratory, Cincinnati, Ohio
This report is a summary of our current research aimed at modification of
wastewater treatment processes to efficiently remove nitrogen via a biological
process.

Figure 1 is a simple flow sheet of the nitrogen cycle during wastewater treat-
ment. Several points are evident. First, if conditions are not proper for nitrifica-
tion to occur, any ammonia in excess of that needed for cellular synthesis will be
discharged in the final effluent, and very little nitrogen removal will be observed.
Second, for denitrification to occur nitrification must be controlled, and a source
of organic carbon must be available. The reaction of nitrite with a primary amine
is the classical Van Slyke reaction and does not occur to any great extent in bio-
logical systems. Tnis figure illustrates the importance of understanding the se-
quence of events when attempting to manage a complex biological system.

Our early studies to control deaitrification were attempts to modify existing
'structures to accomplish efficient nitrogen removal. Figure 2 is the first modi-
fication tried. The air diffusers from the first two sections of a conventionally
operated 100-gallon-a-day activated sludge pilot plant were removed, and the
sludge kept in suspension by stirring. In all the studies reported here the sludges
produced during treatment were digested anaerobically and. the supernatant re-
turned r.o the process at the primary settler. All nitrogen removals, unless other-
wise sealed, are overall removals. A pump to recycle mixed liquor (100 percent
of influent flow) was installed between the aerator exit and the final settler. The
rationale of this system was to recycle the a'ctive solids from the mixed liquor
with the associated nitrates to the anaerobic section where the organic carbon in
the primary effluent would force denitrification to occur. Nitrogen removal was
encouraging but varied widely; however, with this modification nitrate would always
be discharged in the effluent because.of the split stream at the mixed liquor exit.
We therefore tried systems that would treat the entire secondary effluent flow.

Figure 3 is a system of alternate aerobic and anaerobic sections. Because
of the short detention time in each section and the cycling of the organisms be-
tween aerobic and anaerobic conditions, process control was unstable and the abil-
ity to nitrify was lost. The only nitrogen removal was with the primary sludge.

Figure 4 illustrates the next attempt to accomplish controlled denitrification.
A holding tank was installed between the mixed liquor exit and the final settler to
provide detention time for denitrification to occur. As indicated, nitrogen removals
were not much better than the original system'in Figure 2. Only about 50 percent '

1-26
-------
1-27
of the oxidized nitrogen was denitrified in a six-hour period. This was because
at the mixed liquor exit the organisms had a very low respiration rate, and the
major fraction of the organic carbon had been degraded during the conventional
aeration ahead of the denitrification tank. We tried various additives to this tank
to serve as a source of organic carbon, such as primary effluent, primary sludge,
and glucose. Each proved to have disadvantages as listed in Table I.

After considering these results, it was apparent that to control nitrification,
denitrification, and keep detention times as short as possible a system such as
shown in Figure 5 would be necessary. We are currently working with this system
in a 200-gallon-per-day pilot plant. There are three separate sludge systems,
each operated as a separate but interrelated unit process.

The high rate sludge system removes about 80 percent of the influent carbon
as cellular material and carbon dioxide. The effluent from this unit containing
residual carbon and the bulk of u;e influent nitrogen, in the form of ammonia,
goes to a nitrification system. Since the majority of the carbon has been removed,
danger of washout of nitrifiers by excessive sludge washing is eliminated. This
unit has its own sludge system and, therefore, can be considered an enriched
culture of nitrifiers. Nitrification is accomplished in three hours. The high
quality nitrified effluent then goes to the denitrification section. We have found
it necessary to add an organic carbon source at this point. Methyl alcohol has
been tried and found to be very satisfactory. The organisms oxidize rather than
synthesize this material, and residual methyl alcohol has not been found in the
effluent. As shown in the last entry of Table I denitrification efficiency is high.
Overall nitrogen removals of 85 percent have been obtained. However, the pro-
cess is not under complete control, as indicated by the spread in the removal .
efficiencies. Much of the trouble in process control is due to the pilot scale
size of the operation; management of a three-sludge system with small sludge
lines and limited linear flows is difficult. It is planned to study this system in
a 0. 5 mgd demonstration plant.
-------
FIGURE 1
1-28
Influent
Nitrogen
Cellular
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-------
ALTERNATIVE METHODS OF PHOSPHORUS REMOVAL*
Jesse M. Cohen
Introduction

1. At the present time, reagents based on iron, aluminum or lime
are the chemicals of choice for removal of phosphates from wastewater.

2. Eventually, a variety of reagents and methods will be available
to provide a wide choice of design and performance for removal of phosphates.

3. None of the methods discussed here are now ready for practical
application.
Activated Alumina

1. Activated alumina is a synthetic material consisting largely of
aluminum oxide and available in a variety of forms ranging from powders to
granules.

2. The unique properties are its high specific surface area,
200-^00 m-/gram, and its ability to selectively sorb phosphates. Moreover,
when operated in a column mode, alumina can be loaded and regenerated for
a great number of cycles with only 5-8% loss of alumina per cycle.

3. Virtually complete, > 99%, removal of phosphates is obtained. A
feed phosphate concentration of 25 nig/1 showed no detectable phosphate in
the product until more than 1000 bed volumes have passed.

4. Capacity to remove polyphosphates is better than for orthophosphate.

5. As a possible polishing process, better than 99% removal can be
obtained from a 1 mg/1 solution while producing 20,000 bed volumes of product,

6. Special advantages are: No dissolved solids are added to product,
no pH changes occur, feedwater composition and quality have little effect
on removal efficiency, residual phosphates are very low, «= 0.05 mg/1 of
phosphate.

7. Chemical costs are estimated as 3.9 cents/1000 gals for a feed
concentration of 14 mg/1 of phosphate.
*Talk delivered to Workshop on Phosphorus Removal, Chicago, Illinois,
May 1 & 2, 1968.
-------
Lanthanum

1. Based on solubility of its phosphate salt, lanthanum must be
considered as a possible precipitant.

2. Theoretical solubilities are not obtained with iron or aluminum
because cf competing hydrolysis reactions which reduce the metal ions
available for phosphate precipitation.

3. Studies have shown that lanthanum is only slightly hydrolyzed
and shows less tendency to form soluble complexes with phosphate.

4. Desk top considerations predict that lanthanum can be recovered
by treatment with alkali and then reused.

5. A recent price quotation of 60(5 per pound of lanthanum in a
lanthanum-rich mixture of rare earths (down from $3.00/lb) is encouraging.
Ion Exchange

1. Ion exchange materials, both natural and synthetic have potential
for phosphate removal.

2. An important group of naturally occurring ion-exchange materials
are the zeolites and clay minerals.

3. Anion exchange capacities of clays are too small to be economically
useful, but chemical modifications can produce increased capacities.

4. Process based on chemically modified clay minerals can become
economically attractive. Clays are abundantly available and cheap -
just cents per pound.

5. Synthetic ion-exchange materials have adequate anion exchange
capacities but poor selectivity.

6. Since resins exchange both sulfate and phosphate about equally
well, capacity must be shared with these anions. The problem is that
wastewater contains 2-5 times as much sulfate as phosphate.

7. A synthetic ion-exchange resin with high selectivity for phosphate
anion is needed.
-------
3.

1. Soil systems, as treatment devices rather than as means of dis-
posal, are potentially cheap methods of removing phosphates.

2. Soil treatment mechanisms include biological oxidation, adsorption,
chemical oxidation, chemical precipitation, ion exchange and plant
assimilation.

3. Potential of soil to remove phosphate is enormous. During 6 years
of field study, 1.6 tons of phosphorus was fixed in the upper 6 inches of
an acre of soil. Phosphate capacities of some soils range from 11.2 to
40 tons to as high as 205 tons of phosphorus per acre half-foot. Operating
a soil system at 1 gal/d/sq ft, phosphorus capacity would not be exhausted
for upwards of a century.

4. Phosphate fixation in soil can be attributed to many factors such
as anion exchange, adsorption, chemical precipitation and plant assimilation.

Reverse Osmosis

1. Reverse osmosis is a process which uses pressure and semipermeable
membranes to force water to be transported through the membrane leaving
salts and other molecules behind.

2. This process is being developed principally as .a device to remove
contaminants in general.

3. Membranes show selectivity for ions proportional to valence; hence,
multivalent phosphate and sulfate are more completely removed than chloride.

4. If reverse osmosis can be developed to an economically useful
process for partial dernineraliEation, it is useful to know that phosphate
will be almost completely removed.

Up-flow Clarification

1. Sludge-blanket or up-flow clarification offers an alternative
device to horizontal-flow flocculators and sedimentation basins.

2. Principal advantages are: reduced capital costs, reduced land
requirements, reduced detention time, multi-functional processes in a
single unit.
-------
4.

3. Ability to remove pollutants such as phosphates, suspended solids,
color and organic solids, is equal to or greater than horizontal equipment.
Intimate contact with sludge blanket enhances chemical and physical reactions.

4. Preliminary laboratory results show 80-9TL removal of phosphates
with blanket depths of 4-3 feet using alum, ferric sulfate or lime.

5. Rates of 10-15 gal/hr/sq ft which provide detention times of
about 1 hour may be used.
Concluding Remarks

1. Alternative methods for removal of phosphate are being considered.

2. None of these alternatives are now ready for application.

3. Research will almost certainly make some of these alternatives
useful for application in specialized instances.
-------
COST OF REMOVING PHOSPHOR FROM WASTEWATER

* By Robert Smith
Seminar on Phosphorus Removal
Chicago, Illinois - May 1 & 2, 1968

It has been shown that phosphorus can be effectively removed from wastewater
by adding chemicals such as lime, alum, ferric sulfate, or sodium aluminate at
various points within the conventional wastewater treatment plant or in a sepa-
rate coagulation and sedimentation step downstream of the conventional plant.
The two principal cost items associated with phosphorus removal are the cost of
chemicals and the cost of disposal of the waste sludge produced.

Reasonably reliable information is available for estimating the cost of phosphorus
removal at a specific site when the characteristics of the wastewater, the cost of
delivered chemicals, and the requirements for sludge disposal are known. Cost
estimates for hypothetical plants are also useful to indicate, roughly, limits of
total cost that might be encountered as a result of installing and operating pro-
cesses for phosphorus removal. Estimated costs for specific items associated with
phosphorus removal together with some guarded estimates for hypothetical plants
are given below.

ADDITION OF ALUM OR SODIUM ALUMDIATE TO THE AERATOR

Earth and Ettinger have shown that the concentration of phosphorus in the effluent
from the activated sludge process can be reduced from 10 mg/1 to about 0.5
by adding one part of aluminum to the aerator influent stream for each part
of phosphorus present in the aerator influent stream. The aluminum can be added to
the aerator in the form of aluminum sulfate (alum) or sodium aluminate both of
which are available in liquid or dry form. In the range .of plants between 1 mgd
and 100 mgd the cost of purchasing the necessary feeding equipment and storage tanks
amounts to only 0.01 - 0.10 cents per 1000 gallons of water treated. Operating
and maintenance cost has not been estimated. The cost of chemicals delivered to
a 100 mgd plant in Columbus, Ohio has been estimated to range between 2.0 and 2.5
cents/1000 gallons for alum and 3«0 - 3«5 cents/1000 gallons for aluminate. Barth
and Ettinger^ have also shown that the phosphorus removed with the waste activated
sludge is retained by the sludge even after the sludge has been subjected to anaer-
obic decomposition for periods far in excess to the normal detention times. Thus,
no abnormal amount of phosphorus will be returned to the activated sludge process
with the digester supernatant. Barth and Ettinger^- found that the addition of
aluminum to the aerator has a beneficial effect on the settling characteristics of
the sludge but no marked improvement of the performance of the activated sludge
process in removing organics was noted.

SEPARATE LIME CLARIFICATION PROCESS

Coagulation and sedimentation following lime addition in a separate process down-
stream of the activated sludge process is somewhat more expensive than adding
chemicals to the aerator. The lime clarification process, however, removes a
Significant portion of the remaining suspended solids and BOD along with the phos-
lorus. Another advantage of the lime clarification process is that ammonia
-------
t
- 2 -
tripping/ which requires raising the pH of the water, can be used downstream
>f the process to remove ammonia from the water,

A high-density solids-contact process similar to the Infilco Densator* is believed
to be the most economical lime clarification process. Waste lime sludge from
the Densator has a density of about 300 grams/liter. A separate sludge thickening
step is, therefore, not required.

The installed cost of Densators and related equipment was supplied? by Infilco/GATX
for plants in the range of 250-^50 mgd and for the range of 0.07 - 0.50 mgd. These
cost estimates which are based on using an overflow rate of 2000 gpd/sq. ft. are
shown in Figure 1.

Land required for a Densator installation is about kO acres for the 450 mgd size.
Taking the cost of land to be $5000 per acre this represents about one tenth of
a cent per 1000 gallons of water treated.

Debt Service charges (lf-l/2$ - 25 yr.) expressed as cents per 1000 gallons of
water treated are shown in Table I.

The cost of operating and maintenance labor was also estimated by Infilco personnel
as about $26"0 per year per mgd of flow at the ^50 mgd size. This is based on four
men on each of three shifts at a cost of $9800 per man-year. This estimate for
operating and maintenance cost was extrapolated to smaller sized plants by means
of a log-log plot having a slope of (-1/3). At the very small plant sizes the cost
timated in this way might be lov.

The cost of operation and maintenance for the Densator installation expressed in
cents per 1000 gallons of water treated is shown in Table I.

The lime dose required will depend on the alkalinity of the water and the target
pH to be achieved or the fraction of phosphorus to be removed. Since no specific
site is being considered a target pH of 11.0 and a lime dose of 227 njg/1 of quick-
lime (CaO) or 300 mg/1 of hydrated line will be used for estimating lime cost.
The cost of purchasing lime in the Chicago, 111. area is about $18.50 per ton when
delivered in lots of 50 tons or more. The amount of quicklime required by the
process is about one ton per day per mgd. The cost of purchasing lime, therefore,
amounts to about 1.75 cents per 1000 gallons of water treated. Infilco also recom-
mends the use of 50 mg/1 of ferrous sulfate to help coagulate and settle the fines.
The cost of ferrous sulfate delivered is about $^1.75 per ton or about 0.87 cents
per 1000 gallons of water treated.

Disposal of the waste lime sludge presents a problem which is greatly affected by
the disposal means available, the cost of recalcination, and the amount of waste
lime sludge produced. For example, if the plant is small and disposal sites are
close and available the most economical method for disposal might be trucking to
a landfill.

* Mention of proprietary equipment does not constitute endorsement by FtfPCA,
-------
- 3 -

On the other hand, when the aasount of sludge produced Is large and the disposal
sites are at a great distance, recalcination and reuse of the lime is likely to
be the most economical solution.

In Cincinnati the cost of hauling sludge by truck was found to be 32 cents per
ton-mile for a one mile one-way trip and, 5 cents per ton-mile or less for one-
vay trips of more than 2k miles. For a 25 mile one-way trip the cost of sludge
disposal is about 0.6? cents per 1000 gallons of water treated. Barging to sea
from the Washington, D.C. area was found to cost 1.6 cents per ton-mile for a
450 mile one-way trip. This represents about 1.9 cents per 1000 gallons of
water treated. A pipeline cost study" was made by Rand Development Corp. based
on a pipe 160 miles long. If the waste sludge pumped through the pipeline Is
assumed to have a density of 35 grams/liter the cost of sludge disposal would
be about 2.1 cents per ton-mile. Crow9 reported a disposal to landfill cost
in Gainesville, Plordia of $23 per ton of feed lime.

Another factor in computing the advantage of recalcination and reuse of lime is
the hardness of the water treated and the target pH used. For example, Crow9
reported that 1,24 Ib. of quicklime had been recovered by recalcination for each
pound of quicklime used in the process. When the concentration of calcium in
the feedwater is low (soft water) the recovery by recalcination might be only
70$ of the lime used in the process.

As the pH of the water is raised above about 10.0 increasing amounts of calcium
escape in the effluent. This is shown for a specific case in Figure 2. Recovery
of lime by recalcination is thus hampered.

Estimates for the cost of recalcinins waste sludge from water treating plants
range from $12 per ton for a 150 ton/day plant to $3^ per ton for a 6 ton/day
plant. The total cost of recalcination can be estimated roughly from the follow-
ing relationship.
3O
Total Cost of Recalcination, $/ton = $62/(tons/day)

As mentioned previously, when the design guidelines are known it is possible to
make a fairly accurate preliminary cost estimate for the lime clarification pro-
cess. For hypothetical plants the most reasonable approach is to assume that
lime can be produced by an on-site recalcination plant at about the same cost as
the cost of purchased lime. If makeup lime is required to prevent excessive
build up of phosphorus and other contaminants the cost is thus unaffected. Under
this assumption we can then say that the net saving accomplished by recalcining
the waste lime sludge is equal to the cost of disposal by transportation to a
landfill.

Total estimated cost for the lime clarification process in cents per 1000 gallons
of water treated are shown in Table I and Figure 3.
-------
REFERENCES
»

1. Earth, E.F. and Ettinger, M.B., "Mineral Controlled Phosphorus Removal in
the Activated Sludge Process," Journal Water Pollution Control federation,
Vol. 39, PP. 13^2-13^8, (1967).

2. Buzzell, J.C. and Sawyer, dair N., "Removal of Algal Nutrients from Raw
Sewage with Lime," presented at Missouri Water Pollution Control Assoc.
Meeting, Jefferson City, Missouri, March 1,(1966).

3» Rudolfs, Willed, "Phosphates in Sewage and Sludge Treatment H. Effect on
Coagulation, Clarification and Sludge Volume," Sewage Works Jour*, Vol. 19,
pp. 178-190, (19VT). :

4. Lea, W.L., Rohlich, G.A. and Katz, W.J., "Removal of Phosphates from Treated
Sewage," Sewage & Industrial Wastes, Vol. 26, pp. 261-275, (195k).

5. Owen, R., "Removal of Phosphorus from Sewage Plant Effluent with Lime,"
Sewage & Industrial Wastes, Vol. 25, pp. 5^-556, (1953).

6. Rand, M.C. and Nemerow, N.L., "Removal of Algal Nutrients from Domestic
Wastewater," Report No. 9, Dept. of Civil Engineering, Syracuse University
Research Inst., Jan. (1965).

7. Martin, Hugh J., INFILCO/General American Transportation Corp., "Letter
dated July 26, 1966 containing capital cost of Densator and associated
equipment."

8. Crawley, William A., "Washington, B.C. to Meyersdale, Pa. Sludge Slurry Pipe-
line," Rand Development Corp., Cleveland, Ohio.

9. Crow, W.B. and Wertz, C.F., "Techniques and Economics of Calcining Softening
Sludges," Journal American Water Works Assoc., Vol. 52, pp. 322-332, (1960).
-------
TABLE I
TOTAL COST OF
(Cents per
PHOSPHATE REMOVAL
1000 gallons)
Size of Plant

Capital amortization
Land amortization
Operating and maintenance
Cost of chemicals
Lime
Iron salt
Cost of sludge disposal by hauling
(to land fill (25-mile one-way trip]
TOTAL
Savings if sludge can be
recalcined
TOTAL (with recalcining)
Source: JWPCA, Lake Michigan
1 mgd
•97
.09
.41

1.75
.87 '
.67
4.76
-.67
4.09
10 mgd
•79
.09
.14

1.75
.87
.67
4.31
-.67
3.64
100 ngd
-65
.09
.08

1.75
.87
.67
4.11
-.67
3.44
250 mgd
•59
.09
.06

1.75
.87
.67
4.03
-.67
3.36
Water Pollution Enforcement Conference
-------
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-------
SOLIDS REMOVAL BY CGACULATIOH & SEBIMEHTATION
Capital Cost, Operating & Maintenance Cost, Debt Service
vs.
Design Capacity
H
CD
V
0
t
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CJ
g
&
5-0
i.o
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f Cost Adjusted to June, 1967
10.

•P*
H
O
p*
03
CJ
4 5 6 T a 9 10
4 S 673910
0.01
1.0 10.0
Design Capacity, millions of gallons per day
100.
Figure 3
C - Capital Cost, millions of dollars
A - Debt Service, cents per 1000 gallons(k 1/2 - 25 yr.)
0 &_,M = Operating end Maintenance Cost, cents per 1000 gallons
'f = Total Treatment Cost, cents per 1000'gallons
-------
PHOSPHATE REMOVAL FROM WASTE EFFLUENTS AND

RAW WASTES USING CHEMICAL TREATMENT*

By A. A. Kalinske and G. L. Shell

We have been conducting during the past several'years various

pilot plant studies involving the removal of phosphates, and in

some cases improving effluents generally, using chemical treatment

in solids-contact units. Also, our company has built several such

plants (Reactor-Clarifiers) for the treatment of sewage treatment

plant effluents for industrial uses, primarily for power plant

cooling water. Two of these plants have been in operation for

about 3 and 6 years at Las Vegas, Nevada power plants. This is a

summary report in which data will be presented from the pilot plant

studies and, also, from one of the full-scale plants at Las Vegas,

for which fairly extensive operating data have been kept for over

A. Pilot Plant Studies at Colorado Springs, Colorado

Of Trickling Filter Plant Effluent

The City of Colorado Springs has a conventional trickling

filter treatment plant which produces an effluent that is not of

particulary high quality, especially during the winter, as the

plant is somewhat overloaded. The City decided to embark on a

water reclamation program, and part of this was the treatment of

a portion of the effluent as make-up cooling water for their power

plant.
*Presented at Phosphorus Removal Conf., FWPCA, Chicago, 111.,
June 26-27, 1968.
(1) Director of San. Engr. R & D, (2) Chief Sanitary Engineer, Eimco
Corp., Salt Lake City, Utah.
-------
-2-

Among the requirements for this reclaimed effluent was that the

total phosphate not exceed about 1.0 mg/1 as P, and preferably less.

A cooperative arrangement was entered into between Eimco Corp.

and the City to carry on various pilot plant studies which have now

been completed. It was decided to use teritary chemical treatment

of the effluent, using a solids-contact type unit, and to study

both lime and alum treatment. The pilot plant was designed to

handle about 25 gpm, which gave a hydraulic loading of 1400 gpd/ft^

and a total retention time of 1.25 hrs.

The total test period occupied about 1% years so all the varia-

tions in sewage effluent characteristics would be encountered,

including the temperature variations, which had a pronounced effect

on the quality of the STP effluent. The data presented herein are

the averages of months of test work and, therefore, we believe

can be used with confidence both from the technical and economic

In Tables 1 and 2 are shown the phosphate removals obtained

with various dosages of lime and of alum. All phosphorus values

are expressed as total P. Note that these data are on unfiltered

samples obtained from the solids-contact unit, which was operated

at about an overflow rate of 1400 gpd/ft , though we would

recommend that the lime treatment could be operated at about 1800

2
gpd/ft while the alum treatment unit should not be operated over

1200 gpd/ft due to the difference in settling characteristics of

the floe and the slurry produced in the solids-contact unit.
-------
-3-

Filtration of the samples through No. 42 Whatman paper further

reduced the effluent P about 60%. The suspended solids from the

treatment unit averaged about 10-20 mg/1.

In Tables 3 and 4 are shown a summary of what we considered,

for the treatment desired, was the lowest lime and alum dosages

that could be used, not only for obtaining the desired phosphate

removal but for removal of other materials as indicated, since

the solids-contact unit was to be followed by filtration and

activated carbon contacting.
o

One could conclude that an 80% P removal could have been

obtained with a lime dosage of about 200-250 mg/1, or an alum

^^ dosage of about 125-150 mg/1 plus a samll amount of coagulant aid.

For the dosages of 325 mg/1 of lime or 175 mg/1 of alum (plus

1/4 mg/1 of polymer aid), Table 5 shows an economic comparison

for the 2 types of treatment, and the unfiltered effluent quality

that can be expected. For the lime treatment the effluent was

neutralized with acid, at a cost indicated, from a ph of 10.5 to

about 7.0. The total chemical costs appear to be about 5 cents/

1000 gals., for either treatment, and with essentially comparable

effluent quality, though the alum treatment does give a lower

The full-scale plant at Colorado Springs is to have a capacity

of 2 MGD.
-------
-4-

The solids-contact unit installed cost of this size will be about

$75,000 which when amortized over 20 years at 5% amounts to about

1 cent/1000 gal. If reclamation of the lime from the sludge would

be feasible for this size of plant, the operating cost could be

reduced, but more capital equipment would be needed.

However, in evaluating the difference in total costs of the

lime and alum treatments consideration must be given to the differ-

ence in the character of the sludge produced. On the basis of the

above described tests there was 4000 Ibs/day of dry solids produced

per million gallons of effluent with the lime treatment at the

dosage of 325 mg/1. This sludge thickened by gravity readily to

10% solids, which means 5000 gals/day of sludge for disposal. With

the alum treatment, 2000 Ibs/day of solids per million gals were

produced, but the volume was 12,000 gals since it could only be

thickened to 2% by weight by gravity. Such alum sludge could be

mixed with the waste biological sludge and dewatered on a vacuum

filter. The lime sludge could be dewatered on a vacuum filter,

and at 5000 gals/day such a filter would cost, installed, about $8,00

B. Pilot Plant Studies Using Lime Treatment of Raw Sewage

It has been shown that phosphates can be removed by using

chemical treatment on the raw sewage, and this might have overall

economic advantages since such treatment would also remove a signi-

ficant amount of the BOD, thus permitting reduction of the secondary

biological plant, with resultant less biological sludge produced.
-------
-4-

The solids-contact unit installed cost of this size will be about

$75,000 which when amortized over 20 years at 5% amounts to about

1 cent/1000 gal. If reclamation of the lime from the sludge would

be feasible for this size of plant, the operating cost could be

reduced, but more capital equipment would be needed.

However, in evaluating the difference in total costs of the

lime and alum treatments consideration must be given to the differ-

ence in the character of the sludge produced. On the basis of the

above described tests there was 4000 Ibs/day of dry solids produced

per million gallons of effluent with the lime treatment at the

dosage of 325 mg/1. This sludge thickened by gravity readily to

10% solids, which means 5000 gals/day of sludge for disposal. With

the alum treatment, 2000 Ibs/day of solids per million gals were

produced, but the volume was 12,000 gals since it could only be

thickened to 2% by weight by gravity. Such alum sludge could be

mixed with the waste biological sludge and dewatered on a vacuum

filter. The lime sludge could be dewatered on a vacuum filter,

and at 5000 gals/day such a filter would cost, installed, about $8,000.

B. Pilot Plant Studies Using Lime Treatment of Raw Sewage

It has been shown that phosphates can be removed by using

chemical treatment on the raw sewage, and this might have overall

economic advantages since such treatment would also remove a signi-

ficant amount of the BOD, thus permitting reduction of the secondary

biological plant, with resultant less biological sludge produced.
-------
-5-

The same solids-contact unit, described previously, was operated

on screened raw sewage at Colorado Springs at a hydraulic loading

of 1400 gpd/ft . The results obtained are shown in Table 6.

Note that the effluent P obtained was not quite as good, for

the same lime dosage, as was obtained when treating the effluent.

Thus for 300 mg/1 of lime, the P was reduced on an average from 6.2

to 0.7 (89%) , while with 325 mg/1 added to the effluent the reductior

was from 9.7 to 0.5 (95%). There is every reason to expect this,

as undoubtedly a portion of the lime . is "tied up" by reacting

with the various complex organics present in raw sewage. These

results are contrary to some others that have been reported, and

we therefore checked this further in our Salt Lake City Laboratory

using raw and treated SLC sewage, and obtained essentially the same

general difference.

However, we definitely confirmed that solids recycle, and the

contact with previously formed solids, as obtained in a solids-

contact unit, is extremely beneficial in obtaining the full benefits

of the lime used.

As we said initially, this method of treatment should be evalu-

ated against teritary treatment of the effluent where it can be

used, since even though somewhat more lime will be required, it does

reduce the BOD load on the secondary plant. However, it cannot be

used economically simply be adding the lime to the raw sewage

entering an existing primary clarifier.
-------
-6-

Good mixing and solid-contacting are essential, and this would

require significant modifications to any existing "conventional"

biological treatment plant of whatever type.

C. Phosphate Removal In Full-Scale Plants

At Las Vegas, Nevada

The Nevada Power Co. previous to 1961 had used the effluent

from the Las Vegas trickling filter treatment plant for cooling

water. However, as the phosphates gradually increased, averaging

35 mg/1 as PO^, it was mandatory that they be removed before the

effluent could continue to be safely used. Therefore, in 1961 a

2500 gpm solids-contact unit (Eimco Reactor-Clarifier) was installed

to remove phosphates and also excessive suspended solids from the

sewage plant effluent. In 1964 another power station was built

and a 2000 gpm solids-contact unit was installed at this plant.

The necessary quantity of sewage effluent is pumped to these 2

treatment units. These installations with some operating data are

described in a paper by W. H. Johnson, in the Proc. of the

International Water Conference, Engrs. Soc. of Western Penna.,

Sept. 1964, p. 73.

The prime purpose of these treatment plants was to reduce the

phosphates to low values. In Table 7 data are given, as 2-year

averages, for one of the units. Note that P is reduced from about

10.0 to 0.6 at a lime dosage of 240 mg/1 with 3 mg/1 of a coagulant

aid.
-------
-7-

The chemical costs are about 5 cents per 1000 gals. The installed

cost of each solids-contact unit, including piping, feeders, etc.

was about $100,000, which amortized over 20 years at 5% amounts

to a cost of about 1 cent/1000 gal.

The sludge is lagooned in the desert; it concentrates to

about 11% in the Reactor-Clarifier units. The excellent treatment

obtained, with a significant hardness reduction, which is difficult

to achieve when treating sewage plant effluent with lime, is due

to the very high solids that are carried in circulation, thus

providing the necessary solids-contact treatment in the reaction

zone.
-------
TABLE 1.
PHOSPHATE REMOVAL FROM TRICKLING FILTER EFFLUENT
WHEN TREATED WITH LIME
Influent
Lime Dosage
mg/l
250
300
350
400
PH
7.4
7.5
7.4
7.4
P
mg/l
10.0
10.0
10.4
10.7
Effluent*
PH
9.8
10.3
10.8
11.0
P
mg/l
1.07
.93
.60
.60
Removal
89
91
94
95
* Unfiltered sample
TABLE 2.
PHOSPHATE REMOVAL FROM TRICKLING FILTER EFFLUENT
WHEN TREATED WITH ALUM
Alum Dosage
mg/l
175
175 + 1/4 Coag. Aid
200
225
* Unfiltered sample
Influent
P
mg/l
5.9
10.5
8.8
9.0
Effluent*
P
mg/l
1.3
1.0
1.3
0.7
% Rei

78
90
85
92
-------
-------
TABLE 3.
TRICKLING FILTER EFFLUENT TREATMENT
(325 mg/l Lime + 1/4 mg/l of Coag. Aid)
BOD, mg/l
SS, mg/l
P, mg/l
ABS, mg/l
Total Alk. mg/l
Hard, mg/l
pH
* STP Influent
Influent*
34
54
9.7
2.6
198
176
7.2
Effluent
9
11
0.5
2.2
200
170
10.5
% Removal
74
80
95
18

TABLE 4.
TRICKLING FILTER EFFLUENT TREATMENT
(Alum 175 mg/l + 1/4 mg/l of Coag. Aid)
Influent* Effluent % Removal
BOD, mg/l 34 5 85
SS, mg/l 37 11 70
P, mg/l 10.7 1 91
ABS, mg/l 2.3 1.5 35
pH 7.1 6.7
• STP Effluent
-------
TABLE 5.

COMPARISON BETWEEN LIME AND ALUM TREATMENT IN
SOLIDS-CONTACT UNIT OF TRICKLING FILTER EFFLUENT
CHEMICALS
Coagulant, mg/l
Coag. Aid, mg/l (4)
Neutralizing Acid, Ib/MG (3)
Total Cost, $/MG
EFFLUENT QUALITY
BOD, mg/l
COD, mg/l
SS, mg/l
Total P, mg/l
Alum (1)
175
V4

5
47
11
1
Lime (2)
325
V4
1340
55

9
88
11
0.5
(1) Based on 4 cents/lb.
(2) Based on 1.25 cents/lb.
(3) Based on 1.1 cents/lb.
(4) Based on $2.00/lb.
-------
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-------
TABLE 7.
TREATMENT OF TRICKLING FILTER EFFLUENT (1 MGD) IN
SOLIDS-CONTACT UNIT: AVE. DATA FOR 1967 AND 1968.
(Lime Dosage 240 mg/l + 3 mg/l Nalco 603)
Influent Effluent
Total P, mg/l 10.0 0.6

BOD, mg/l 21
COD, mg/l 88
SS, mg/l 31 5
TDS, mg/l 755 630
Hardness, mg/l 352 298
Calcium, mg/l 155 190
Magnesium, mg/l 192 118
Total Alk., mg/l 285 132
pH 7.5 10.2
-------
HIGH RATE SEDIMENTATION IN WATER TREATMENT WORKS
By

Gordon Gulp, Research Manager
Sigurd Hansen, Research Engineer
Gordon Richardson, Laboratory Manager

Neptune MicroFLOC, Inc.
Corvallis, Oregon

Presented on June 4, 1968, at the American Water Works Association's 88th
Annual Conference, Cleveland, Ohio.

PRINCIPLES OF HIGH RATE SEDIMENTATION

It has long been recognized that a settling basin should be as shallow as
possible and that detention times of only a few minutes could be used in
very shallow basins. For example, a particle settling at a rate of 1 inch
per minute requires 120 minutes to fall to the bottom of a conventional
clarifier of 10 foot depth. If the basin were 2 inches deep, this parti-
cle would fall to the bottom in only two minutes. In 1904, Hazen (1) pre-
sented his argument that settling basin efficiency is primarily dependent
upon basin depth and overflow rate and is independent of detention time.
He proposed basin depths of as little as 1 inch. Over 20 years ago, Camp
(2) proposed settling basin depths of 6 inches and total settling basin
detention times of 10 minutes .

A detailed literature review by the authors (3) showed that there have
been many attempts at applying the shallow depth sedimentation principles
proposed by Hazen and by Camp. Wide, shallow trays were generally inserted
within basins of conventional design. These attempts met with only limited
success because of two major problems: (a) the unstable hydraulic conditions
encountered with very wide, shallow trays, and (b) the minimum tray spacing
was limited by the vertical clearance required for mechanical sludge removal
equipment. The authors have overcome both of these problems by using very
small diameter tubes rather than wide, shallow trays. Longitudinal flow
through tubes with a diameter of a few inches offers theoretically optimum
hydraulic conditions for sedimentation and overcomes the hydraulic problems
associated with tray settling basins. Such tubes have a large wetted peri-
meter relative to the wetted area and thereby provide laminar flow conditions
as evidenced by very low Reynolds numbers. Fischerstrom (4) felt Reynolds
number of less than 500 in settling basins would be most beneficial to the
settling process. A 1 inch diameter tube, 4 feet long, through which
water is passed at a rate of 10 gpm per square foot of cross-sectional area
has a Reynolds number of only 24 while providing an equivalent surface overflow
rate of 235 gpd per square foot. The 3 minute detention time of such a
tube settling device under these conditions certainly makes the cost and
space saving potential apparent. The authors now have tube settling devices
in operation in many water treatment plants which are providing excellent
clarification with settling detention times of less than 10 minutes.
nepluns
-------
The authors recently made detailed presentations of their research on tech-
niques for applying shallow depth tubes as sedimentation devices (5). The
purpose of this paper is to present operating experiences with applications
in water treatment plants and to present additional research data.
BASIC TUBE SETTLER CONFIGURATIONS

The authors have described (3, 5) two basic tube configurations which are
shown in Figure 1: (a) essentially horizontal and (b) steeply inclined.
The operation of the essentially horizontal tube settlers [described in
detail in reference (3)] is coordinated with that of the filter used to
clarify the tube settler effluent. Each time the filter backwashes, the
tube settler is completely drained. The falling water surface scours the
sludge deposits from the tubes and carries them to waste. The water
drained from the tubes is replaced with the last portion of the filter
backwash water. The tubes are inclined only slightly in the direction of
flow (5°) to promote the drainage of sludge during the backwash cycle.
If the inclination of the tubes is increased to a steep angle (45° - 60°),
continuous gravity drainage of the settleable material from the tubes can
be achieved (5). The incoming solids settle to the tube bottom and then
exit the tubes by sliding downward along the tube bottom. A flow pattern
is established in which the solids settling to the tube bottom are trapped
in a downward flowing stream of concentrated solids. This countercurrent
flow of solids aids in agglomerating particles into larger, heavier
particles which settle against the velocity of the upwardly flowing liquid.
The continuous sludge removal achieved in these steeply inclined tubes
eliminates the need for drainage or backflushing of the tubes for sludge
removal.
ESSENTIALLY HORIZONTAL TUBE SETTLER

The essentially horizontal tube settler has been used primarily in small
(15,000 gpd) to medium sized (10 MGD) water treatment plants where the
elimination of operator attention for sludge removal from the clarifier
is a significant benefit. By draining the tubes each time the filter
backwashes, positive sludge withdrawal from the clarifier is achieved. The
entire backwash - tube drainage cycle is automated. Thus, no operator
judgement on when or how much sludge to withdraw from the clarifier is
required. A schematic of a package water treatment in which tube settling
has been used is shown in Figure 2. The detention time within the tubes,
at design flow, is 6 minutes. The impact of this low residence time on the
plant dimensions is well illustrated by the 6 foot high by 6 foot wide by
14 foot length dimensions for a complete 100 gpm water treatment plant pro-
viding flocculation, sedimentation and filtration in one rectangular, prefabri-
cated, steel plant. As shown in Figure 2, the coagulated raw water may first
be passed upwards through a fluidized calcite column which automatically main-
tains the pH in the proper range for good coagulation. If alum is overfed,
the calcite will automatically buffer the coagulated water. The use of
calcite for this purpose eliminates one possible cause (overdosage of coagulant)
of poor finished water turbidity.
-------
The tubes used in these essentially horizontal tube settlers are hexagonal
in shape. The hexagonal tubes nest together to form a honeycomb pattern,
as shown in Figure 3. The tremendous wetted perimeter of such a tube
configuration relative to its wetted area provides extremely low Reynolds
numbers, well within the laminar flow range.

The effects of tube length, diameter, and flow rate on tube settler
efficiency have been presented earlier (3). Tube diameters of 1 to
2 inches and lengths of 2 to 4 feet are used in most water treatment
applications. Hydraulic loading rates of 3 to 5 gpm per square foot
of tube entrance area are generally used. Data have been presented (3)
which show that the tube settler, mixed-media filter combination in a
plant with total detention time of less than 30 minutes provides efficient
clarification of very turbid waters (1000 JU), highly colored waters, waters
containing filter-clogging algae, waters containing iron and manganese, and
raw waters with taste and odor. Since these data were published, confirming
operating data from several plants with capacities of 30,000 gpd to 3 MGD
have been obtained from field installations. The partial list of these
plants shown in Table I illustrate the wide range of water quality being
subjected to treatment in plants employing the basic flow pattern shown in
Figure 2. The majority of these plants are being used for potable supplies
and are operating at total plant detention times of about 30 minutes. Although
this detention time is greatly less than that in plants employing conventional
sedimentation techniques, data collected in prototype studies indicate the
plants are actually conservatively rated. To illustrate this, Figure 4 presents
data collected during one of these studies with a plant as shown in Figure 2.
During this test, each of the plant components was being operated at rates
considerably higher than the design criteria normally used for these plants,
i.e., tube settler detention 3 minutes rather than 6 minutes, filter rate
8.5 gpm per square foot rather than 5 gpm per square foot, flocculation time
5.4 minutes rather than 10 minutes. The plant operating with an overall
detention time of 16 minutes reduced average raw water turbidity of 1000 JU
to an average of less than 0.1 JU. Although the filter rate of 8.5 gpm
per square foot resulted in a relatively high initial headloss (2.7 feet H20),
the percentage backwash water at the end of the 8 hour run was only 2.5 per-
cent. If the run had been continued to the normal backwash headloss value
of 8 feet, the backwash requirement would have been less than 2 percent. These
data well illustrate how the mixed-media filter (coal, sand, garnet) complements
the tube settler to accomplish what may certainly be classed as "high rate"
clarification.
Flow Distribution

Flow distribution problems are much less severe in the tube settler than in
earlier tray settling devices. One of the major reasons is the extremely
stable hydraulic condition established within the tubes. As discussed
earlier in this paper, laminar flow conditions are established in the tubes.
Thus, there are no turbulent flow conditions to promote short circuiting.
Also, it has been found that the sludge deposits within the tubes act as
flow distribution aides. If one tube is receiving more flow than another,
the more rapid buildup of sludge in the first tube will cause some flow to
be diverted to the second tube. The sludge deposits themselves thus act as
a "self-orificing" device in the horizontal tube settlers. Of course, care
must be taken in the design of the tube inlet and outlet conditions so that
no great velocity gradients are established across either the inlet or outlet
faces of the tube
-------
TABLE I
Partial List of Installations of Water Treatment Plants
Using Horizontal Tube Settlers and
Mixed-Media Filtration
Location

British Columbia

Oregon
Facility Served

Nuclear Reactor

Recreational Area

Recreational Area

Oil Field Reuse

Municipality-Pilot

Recreational Area

Municipality
Plant Capacity
(gpm)
100

500
Treatment Problem

10-100 JTU Turbidity

10-65 JTU Turbidity

2-28 JTU Turbidity

2-30 JTU Turbidity

30-150 JTU Turbidity
20 Color

10-40 JTU Turbidity

10-35 JTU Turbidity

5-15 JTU Turbidity,
pH 3.5, Iron 2.8 mg/1,
Manganese 1.0 mg/1

Oil and Suspended
Solids

10-20 JTU Turbidity

10 JTU Turbidity

4.5 mg/1 Iron,
160 Color

25 JTU Turbidity,
1 mg/1 Iron, 20 Color

10-1000 JTU Turbidity,
20 Color

5-10 JTU Turbidity
20 Color, Algae
-------
Flow distribution analyses have been made in a 20 gpzn plant as shown in
Figure 2, utilizing the salt tracer technique (6). A batch addition of a
solution containing 50 grams per liter of sodium chloride was dispersed
into a stabilized flow of untreated source water in the flocculator.

Conductivity analyses of samples collected at five minute intervals from
the influent and twelve vertical and lateral effluent settler locations
showed a variation in peak value of ±10 micromhos on triplicate runs.
Comparing the variation in conductivity with the corresponding salt as
chloride concentration indicated sufficient linearity existed to allow
the data to be evaluated on the basis of conductivity.

Distribution of the inlet flow to the individual tubes can be considered
satisfactory based upon the minor variation experienced in peak effluent
conductivity and that the individual tube samplings were found to have
retention times 4 percent less than the theoretical sampling retention
period.

Analyses of the tube effluent composite sample with time indicated a mini-
mum of short circuiting existed in that the volumetric displacement effic-
iency was found to be 84 percent as compared with that of 63 percent listed
(6) for ideal basins. *
-------
STEEPLY INCLINED TUBE SETTLERS

As discussed earlier, the solids which settle to the bottom of a tube
inclined at a steep angle (greater than 45°) will slide down the tube
bottom continuously. This enables sludge removal to be achieved with-
out draining or backflushing the tubes.

Although the benefits of this continual sludge removal phenomenon are
obvious, the effects of steeply inclining the tubes on the path of the
particles as they settle requires more detailed consideration. The
path traced by a particle settling in a tube is the resultant of two
vectors: V, the velocity of flow through the tube and vs, the settling
velocity of the particle. It can be seen in Figure 5 that if the settling
surfaces are inclined upward in the direction of flow, the settling path
of the particle is altered because the component of the settling velocity
which is parallel to the tube wall, vsh, is opposite in direction to the
velocity vector V. If V is greater than vs, the required length of the
settling surface decreases as the angle increases from zero up to about
25 to 30 degrees (at V=2.5 vs) and then increases, approaching infinity
as the angle of inclinitation is increased to 90 degrees. For V
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tubes were repositioned at angles of 35, 40, 45, and 60 degrees. A
slight decrease in efficiency (Figure 8) was noted as the angle of in-
clination approached 60°. However, the self-cleaning action was enhanced
as the angle was increased from 45° to 60°. To insure adequate sludge
removal from the tubes, an angle of inclination of 60° was used in the
subsequent tests of multi-tube units.
Field Evaluation - Pilot Plant Scale

A plant of the type shown in Figure 2 was modified for the first field
evaluations of the steeply inclined tubes. As shown in Figure 9, the
plant was evaluated with the tubes at a 5° inclination and at a 60° in-
clination. The tubes used were 2 feet in length and 1-1/2 inch in dia-
meter. Because the tube chamber was originally designed for 4 foot long
tubes inclined at 5°, a portion of it was blocked off by the plywood
diaphragm shown in Figure 9 for the tests with 2 foot tubes inclined at
5°. The tubes were installed so that the inlet and outlet conditions
and the total tube entrance area were the same with both the 5° and 60°
tubes. The same mixed-media (coal, sand, garnet) filter was used to
filter the tube effluent in both cases . The surface water being treated
was coagulated with alum and, as noted in Table II, polyelectrolyte was
added in some cases. The data shown in Table II show that the water
quality produced by the 60° tubes at 8.5 gpm per square foot was lower
in turbidity than that produced by the 5° tubes at 5.0 gpm per square
foot, with 0.2 mg/1 polyelectrolyte used in both cases. The tube effluent
quality was compatible with the mixed-media filter in all cases and filter
runs to 8 feet of headloss were greater than 18 hours, in all cases. Data
collected during one run of the 60° tubes is shown in Figure 10. The effect
of polyelectrolyte on tube settler efficiency is clearly shown by the
sudden decrease in tube effluent turbidity following the b'eginning of
polyelectrolyte feed at 4.2 hours. The filter effluent turbidity remained
less than 0.1 JU throughout the run. The tube settler detention time
under the conditions shown in Figure 10 was 2.3 minutes.
Field Evaluation of Modular Tube Units - Pilot Plant Scale

Because of the very encouraging results obtained in the preliminary field
tests described above, work was begun on the design of a modular unit of
steeply inclined tubes which would minimize installation problems. Fol-
lowing preliminary evaluation of a great many potential designs, this develop-
ment work resulted in the tube module design shown in Figure II (patent
pending) in which the material of construction is normally PVC. Extruded
PVC channels are installed at a 60° inclination between thin sheets of PVC.
By inclining the tube passageways, rather than inclining the entire module,
the rectangular module can be readily mounted in either rectangular or
circular basins. By alternating the direction of inclination of each row
of the channels forming the tube passageways, the module becomes a self-
supporting beam which needs support only at its ends. Following the
development of this module, field tests of its efficiency as a sedimen-
tation device were begun. A tube cross-section of 2 inches by 2 inches
and a tube length of 24 inches was used in the following tests.
-------
The apparatus (shown in Figure 12) was set up at the authors' laboratory.
The laboratory ground water supply was used. A mud slurry was mixed with
the incoming water to provide various levels of raw water turbidity. Alum
(40 mg/1) was added as the primary coagulant with polyelectrolyte addi-
tions made in some tests. Tube loading of 4-6 gpm per square feet were
investigated (tube entrance area = 9 ft.2) with raw water turbidities of
50 and 250 JU. The data from these tests are summarized in Table III.
In some runs, as noted, the flocculator drive motor was turned off to
evaluate the tube efficiency without prior mechanical flocculation.

At the lower rate of 4 gpm per square foot, the addition of polyelectrolyte
did not markedly improve the effluent clarity. However, when the flow
rate was increased to 6 gpm per square foot, the higher settling veloci-
ties imparted by the polyelectrolyte were of significant benefit. When
the flocculator was operated, the turbidities were fairly constant through-
out the run. However, when the flocculator motor was not operated, it was
found that the effluent turbidity decreased with time as the solids concen-
tration beneath the tubes increased. This is not surprising since solids
contact in and beneath the tubes was the prime source of flocculation in
this case. Although it was found that the sludge blanket could be
established with the steeply inclined tube settler without subjecting
the incoming water to mechanical flocculation, flocculation hastened
the development of the blanket. After the sludge blanket was well esta-
blished, the flocculator could be turned off with no noticeable effect
on the clarified effluent quality. This observation suggests that by
maintaining an upflow of newly coagulated water through a region of
high solids concentration, the external flocculation requirements can
be significantly reduced. This principle, of course, is recognized and
capitalized on by solids contact clarifier manufacturers.

These tests indicated the steeply inclined tube modules shown in Figure II
performed well as a sedimentation device and were capable of producing
settled water turbidities consistent with the capabilities of the mixed-
media filter under all the conditions shown in Table III.
Field Evaluation - Plant Scale

The next logical step in the development of the steeply inclined tube
settling process was a plant scale application. Fortunately, the city
of Newport, Oregon, and their consulting engineer were faced with a water
treatment plant expansion at the time when the tube settling experiments
described above were being completed. The existing 1.5 MGD plant (Figure
13) consisted of a circular flocculator-clarifier followed by rapid sand
filters. The raw water characteristics are as follows: turbidity -
10 to 20 JU; color - 50 to 130 units; pH - 7.6; iron - 4.7 mg/1; tem-
perature - 66° F; alkalinity - 85 mg/1; and hardness - 17 mg/1. The
plant operator normally applies about 35 mg/1 alum and several mg/1 of
activated carbon to the raw water to produce an acceptable finished water
quality. Pilot tests were conducted using a plant of the type shown in
Figure 2. It was found that an alum dose of 30 mg/1 polyelectrolyte
feed of 0.3 mg/1, and 1.5 mg/1 chlorine would enable the tube settler -
mixed-media filter combination to produce a finished water quality of
1.15 JU turbidity, 5 color units, and 0.1 mg/1 iron. The tube settler
'and mixed-media filter were both operated at 5 gpm per square foot
in these pilot tests.
-------
10
TABLE III
Performance of Pilot Plant with Steeply Inclined Tube Modules
Flow Rate
gpm/ft2
4
4
4
4
6
6
6
6
6
6
Floe Time
Min.
7
7*
7*
7*
4.5
4.5
4.5
4.5*
4.5*
4.5
Polyelectrolyte
Dosage
mg/1
0
0
0.1
0.2
0.1
0.2
0.2
0.2
0
0
Average
Raw
Turbidity
JU
50
92
50
54
53
52
231
2.46
49
255
Average
Settled
Turbidity
JU
18
20
20
13
27
21
27
54
35
52
*Flocculator drive motor not operated
-------
11
Based upon the pilot test results, modification of the full scale plant
was begun late' in the fall of 1967 in order to increase the plant capacity
from 1.5 MGD to 3.0 MGD by installation of tube modules in the existing
clarifier and by conversion of the rapid sand filters to mixed-media
beds. As a first step, tube modules were to be installed in the existing
clarifier to evaluate their performance on a plant scale.

Because the available water supply to the clarifier was to be limited by
the existing 1.5 MGD raw water pump during the early tests, tubes were
installed in only a portion of the basin. Tube modules of the type
shown in Figure II were used. The tubes were installed over 1/6 of the
clarifier surface as shown in Figure 15. Tube modules were also used
as support beams for the upper modules, see Figures 15 and 16, so that
none of the clarifier surface was lost due to a support structure. These
radial support beams were attached by PVC pipe to support brackets on
the inlet well on one end and the effluent weir at the other end. The
supporting brackets, pipe, and modules are pictured in Figure 17 while the
installation of a support module is shown in Figure 18. Once the support
beams were in place, the remaining tube settler modules were placed in
position. The portion of the basin in which tubes were installed (pictured
in Figure 19) was isolated from the remaining part of the clarifier by a
plastic barrier attached radially to the clarifier on each side of the tube
section. Flow through the tube section was regulated by closing off portions
of the effluent weir in the rest of the basin by a galvanized sheet steel
plate clamped to the weir plate. Preliminary tests quickly led to closing off
this entire weir area and passing the entire plant flow through only the
210 square feet of the basin covered with tubes. Althoujh the nominal
plant flow was 1.5 MGD, flow measurement during the test period indicated
the raw water pump was actually delivering only 910 gpm. Thus, the hydraulic
loading on the tube area was 4.3 gpm per square foot.

Flow distribution analyses and effluent quality determinations were made.
Because only the existing peripheral effluent weir was used, less-than-
perfect flow distribtuion was anticipated. Although radial collection
weirs would greatly aid in flow distribution, it was desired to first
evaluate the performance using only the existing weir.

The rise rate of hydrochloric acid injected into each tube module at
several points was used to determine the velocity in each module. For
the purposes of identification, the modules were labeled "A," "B," "C,"
and "D" as shown in Figure 15. The resulting flow distribution data
are shown in Figure 20. As was expected, the outer modules nearest the
effluent weir were receiving the bulk of the flow and were operating
at 6.6 gpm per square foot as compared to the average of 4.3 gpm per
square foot based upon the entire surface area covered by tubes. Even
with this flow distribution, the tubes were performing as efficient
sedimentation devices. As shown in Figure 20, the tube effluent tur-
bidity increased only slightly as the flow rate increased from 2 gpm
per square foot in module D to 6.6 gpm per square foot in module A.
The tube effluent contained no settleable solids while samples collected
earlier from the existing clarifier indicated that its effluent frequently
contained 0.2 - 1.0 ml/1 settleable solids and an average turbidity of
5.1 JU. The fact that the tube modules operating at 4.3 gpm per square
foot (average) were producing better effluent than the clarifier previously
-------
12
did operating at "0.7 gpm per square foot was further confirmed by the fact
that the length of filter runs increased from 26 hours to 60 hours following
the modification of the clarifier.

At the time of this writing, the final Newport plant conversion is being
made. The filter media conversion is underway with the design rate for the
mixed-media filter being 5 gpm per square foot. The final clarifier conver-
sion is being made with a ring of tube modules being installed completely
around the periphery of the basin. The tube ring will operate at a rate
of 5 gpm per square foot at 3 MGD. The peripheral location of the modules
was selected to take advantage of the existing effluent collection system
and the resulting flow distribution. If more of the clarifier surface is
eventually covered with tubes to further increase the basin capacity, addi-
tional effluent collection weirs to better distribute the flow would be
needed to realize the full advantage of the additional tube modules.
Summary

Shallow tubes are very efficient sedimentation devices. Two basic tube
configurations have been used: (a) essentially horizontal and (b) steeply
inclined. Sludge is removed from the essentially horizontal tubes by
automatically draining them each time the filter backwashes and refilling
them with filter backwash water. Over 20 water treatment plants employing
these horizontal tubes with sedimentation detention times of less than
10 minutes with capacities of 20 gpm to 2,000 gpm are now in operation.
In tests described in this paper, a plant providing flocculation, tube
sedimentation, and mixed-media filtration, produced potable water (0.1 JU
turbidity) from a raw water turbidity of 1,000 JU with an overall plant
detention time of 16 minutes. Flow distribution analyses show the shallow
horizontal tubes enable good flow distribution to be readily achieved.

The continuous self-cleaning of sludge from tubes inclined at a steep
angle allows sludge removal to be achieved without the need for draining
the tubes. Laboratory and field tests show that an angle of 60° pro-
vides continuous sludge removal while still allowing the tube to func-
tion as an efficient sedimentation device. Pilot plant tests have shown
these steeply inclined tubes to efficiently remove alum floe at rates as
high as 8.5 gpm per square foot. These tests led to the development of
tube modules which were installed in an existing clarifier to
increase its capacity from 1.5 MGD to 3.0 MGD. Analyses of the full
scale installation showed good clarification at rates of 6.6 gpm per
square foot. The installation of the tube modules in an existing clari-
fier and the conversion of the filter to a mixed-media bed provides plant
expansion with substantial savings in cost and space. The coupling of
tube settlers and mixed-media filter allows a reduction in the size and
cost of new treatment facilities. This combination provides new design
concepts to achieve efficient treatment plant design to produce a given
quality finished water from a given raw water or waste water.

Acknowledgements

The steeply inclined tube modules shown in Figure II and the techniques
for installing the modules in the Newport clarifier were devised by
Curt McCann and Stan Aikins, Design Engineers, Neptune MicroFLOC. The
valuable contribution of these two gentlemen to this paper is obvious
and is gratefully acknowledged.
-------
13
References
1. Hazen, A., "On Sedimentation." Transactions of American Society
of Civil Engineers, J53 p. 45 (1904).

2. Camp, T. R., "Sedimentation and the Design of Settling Tanks."
Transactions of American Society of Civil Engineers, 111, p. 895
(1946).

3. Hansen, S. P., and Gulp, G. L., "Applying Shallow Depth Sedimentation
Theory." Journal American Water Works Association, 59, p. 1134
(1967).

4. Fischerstrom, C. N. H., "Sedimentation in Rectangular Basins." Pro-
ceedings of American Society of Civil Engineers, Sanitary Engineering
Division (May, 1955).

5. Hansen, S. P., Gulp, G. L., and Stukenberg, J. R., "Practical
Application of Idealized Sedimentation Theory." Presented at the
1967 Water Pollution Control Federation Conference, New York City
(October, 1967).

'6. "Operation and Control of Water Treatment Processes." Cox, C. R.
Monograph Series No. 49. World Health Organization, Geneva,
Switzerland (1964).
-------
CHEKAL COAGULANTS
FIRST PORTION OF
BW TO WASTE
RAW —
WATER
LAST PORTION OF FILTER
BW REFILLS TUBES
FLOCCULATOR
r
FILTER
TUBE CONTENTS DRAINED
DURING FILTER BW
(a) ESSENTIALLY HORIZONTAL TUBE SETTLER
HEMICAL COAGULANTS
ATER
FLOCCULATOR
TUBE.
ETTLER/
'////A
BW TO WASTE
-^/•vw-v-L
—i i
FILTER
SLUDGE
DRAWOFF

(b) STEEPLY INCLINED TUBE SETTLER
FIGURE I

BASIC TUBE SETTLER CONFIGURATIONS

SHOWN SCHEMATICALLY
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TYPICAL TUBE SETTLER MODULE
FOR USE IN PLANTS SHOWN IN FIGURE 2
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FIGURE 5

EFFECT OF TUBE INCLINATION ON SETTLING PATH OF
DISCRETE PARTICLE
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• FLOCCULATED WATER

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ELEVATION
FIGURE 6

SCHEMATIC DIAGRAM OF TEST APPARATUS USED IN EVALUATfNG EFFECTS

OF TUBE INCLINATION
-------
100
Sgpm/sq.ft
2.5mg/l.
20min.
Flow Rate
Activated Silica
Flocculation Time-
Flow Rate Sgpm/sq.ft
Polyelectrolyte Dosage_0mg/l.
Flocculation Time I2min.
20 30 40 45 50 60

TUBE INCLINATION — DEGREES

FIGURE 7
EFFECT OF TUBE INCLINATION ON SETTLING PERFORMANCE

IN ONE INCH DIA., FOUR FOOT LONG TUBES
-------
100
90
80
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40
30
20
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EXPERIMENTAL CONDITIONS

_ Tube Size f Did., 4feet Long
Ave. Influent Turbidity__ 150 J.U.
Flow Rate 2gpm/sq.ft.
Polyelectrolyte Dosage__0mg/l.
Flocculation Time 20 min.
0 Flow Rate 8gpm/sq.
1 Polyelectrolyte Dosage. _0.5 mg/l.
Flocculation Time 20 min.
T.

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electrolyte DOJ
culation Time.

5gpm/s
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TUBE INCLINATION - DEGREES

FIGURE 8
60
EFFECT OF TUBE INCLINATION ON SETTLER PERFORMANCE
-------
PLYWOOD DIAPHRAGM
OVERFLOW WEIR TO FILTER
FLOCCULATED WATER
INLET WEIR
NLET PLENUM
SECTION VIEW OF PLANT WITH TUBES INSTALLED IN UNIT AT
FIVE DEGREES
OVERFLOW WEIR TO FILTER
7
OUTLET PLENUM
PLYWOOD
\ \\ TUBES
60°
INLET PLENUM
-TUBE SUPPORT FRAME
FLOCCULATED WATER
INLET WEIR
SECTION VIEW OF PLANT WITH TUBES INCLINED AT 60 DEGREES
FIGURE 9

(APPARATUS USED IN PRELIMINARY FIELD EVALUATION OF
STEEPLY INCLINED TUBE SETTLER
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NEWPORT, OREGON

WATER TREATMENT
PLANT
FIGURE 14

TUBE MODULES USED IN
NEWPORT CLARIFIER CONVERSION
-------
SUPPORT MODULE
30°SECTIONS
TYPICAL
FIGURE 15
PLAN VIEW OF MODIFIED NEWPORT CLARIFIER
-------
TUBE SETTLER
MODULES
SUPPORT MODULE
FIGURE 16
SECTION OF MODIFIED NEWPORT CLARIFIER
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FIGURE 17

SUPPORT MODULE
PRIOR TO INSTALLATION
f
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SUPPORT MODULE
BEING INSTALLED
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FLOW DISTRIBUTION AND TURBIDITY DATA IN INITIAL NEWPORT

TUBE MODULE INSTALLATION
-------
HIGH RATE CLARIFICATION OF WASTE WATERS

Presented at the University of Kansas Sanitary Engineering Conference

January 3, 1968

The term "clarification" as used in this paper refers to removal of particulate
matter from waste waters by either gravity sedimentation or filtration. The
high-rate processes described in this paper enable reductions in size of
sedimentation facilities by factors of 5-10 and allow filtration rates of
2-5 times those normally used.

The desire to minimize pollution of the nation's water resources and the
need to supplement these resources have made conventional secondary sewage
treatment processes inadequate in some instances. Many of the tertiary
treatment systems which have been proposed for removal of particulate and
dissolved materials from secondary effluents involve filtration, Filtration
of secondary effluent is a difficult problem in many respects. If the
secondary effluent contains a high solids concentration, as many secondary
effluents occasionally do, a conventional sand filter will blind at the
surface in a very short time, even at low filtration'rates. The reasons
for this are apparent from an examination of Figure 1 which is a cross-section
of the typical single media filter, such as a sand filter. During filter
backwashing, the sand grades hydraulically with the finest particles rising
to the top of the bed. As a result, most of the material removed by the filter
is removed at or very near the surface of the bed. Materials passing the
top few inches of the bed quite likely will pass completely through the
filter. Only a small part of the total voids in the bed are used to store
particulates and headless increases very rapidly. When the secondary effluent
contains relatively high solids concentrations, a sand filter will blind
at the surface in only a few minutes.

One approach to increasing the effective filter depth is the use of a dual
media bed using a discrete layer of coarse coal above a layer of fine sand,
as shown in Figure 2. The work area is extended, although it still does not
include the full depth of the bed, as there is some fine to coarse strati-
fication within each of the layers, as shown by the graph depicting grain
size. Effective size of the sand in a typical dual media filter is 0.4-
0.5 mm.

It is apparent that an ideal filter would be the inverse of a sand filter;
that is, it would have the coarsest material on top and the finest on the
bottom, as illustrated by Figure 3. As shown on the right side of the

neptune
VT—
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1 of 19
-------
—2—
Figure 1
Cross-Section Through
Single-Media Bed
Such as Conventional
Rapid Sand Filter
Grain size
Figure 2
Cross-Section Through
Dual-Media Bed
Coarse Coal Above
Fine Sand
Grain size
Figure 3
Cross-Section Through
Ideal Filter
Uniformly Graded From
Coarse to Fine
From Top to Bottom
-------
-------
-3-
figure, the grain and pore sizes would be uniformly graded from coarse
to fine, from top to bottom. The author's company has developed a unique
method constructing a filter so that it closely approaches this ideal con-
figuration. In this "mixed-media" filter, three or more materials of dif-
fering specific gravities are allowed to intermix, and no attempt is made
to maintain separate or discrete layers of the different materials. The
three materials normally used are coal, sand, and garnet. Garnet has a
specific gravity of over 4 as compared to 2.6 for sand and 1.6 for coal.
The garnet, sand, and coal particles are sized so that some intermixing
of these materials occurs and no discrete interface exists between the
various materials. Of course, the differerences in specific gravity result
in the coarse, lighter coal occupying most of the upper portion of the
filter with the sand occupying most of the intermediate space between the
coal and bottom layer of very heavy garnet. The resulting filter has a
particle size gradation which decreases from about 1 mm at the top to about
0.15 mm at the bottom. The entire filter depth is utilized for floe removal
and storage. The very fine garnet used in the bottom layer of the filter
forces the effluent to pass through a much finer barrier than would be
provided by the coarser sand found in a coal-sand filter. The coarse upper
layer of the mixed-media filter greatly reduces its sensitivity to surface
blinding. Filter depths of 24-30 inches, filter flow rates of 5-10 gallons
per minute per square foot, and backwash rates of 15-20 gallons per minute
per square foot are normally used in secondary effluent filtration. Several
systems in which mixed-media filtration has been used for clarification
of secondary effluent are described in the next few paragraphs.

PLAIN FILTRATION

As shown in Figure 4, a very simple system for further clarification of
effluents is plain filtration. No chemical coagulation of the secondary
effluent is provided before it is passed through a mixed-media filter. The
efficiency of plain filtration is primarily dependent upon the degree of
biologic flocculation achieved in the secondary process. For example,
the biologic flocculation achieved in a trickling filter is relatively
poor and only 30-50 percent of the suspended solids found in a trickling
filter plant effluent will be removed by plain filtration. Conventional
activated sludge systems achieve a stronger biologic floe with the result
that 65-75 percent of the suspended solids in the secondary effluent can
be removed by plain filtration. The longer aeration periods used in
extended aeration plants achieve even a higher degree of biologic floccula-
tion, which enables more than 90 percent of the effluent suspended solids
to be removed by plain filtration. In an activated sludge system, our
research has shown that the efficiency of plain filtration is directly
proportional to the aeration time and inversely proportional to the
load factor (ratio of the amount of organic material added per day to the
amount of suspended solids present in the aeration chamber). Variation
of mixed liquor suspended solids in the normal operating range of 1,500-
5,000 milligrams per liter do not significantly effect the filterability
of the effluent at a given aeration time and load factor. With a load
factor of 0.15 and an aeration time of 12 hours, more than 90 percent of
the suspended solids in an activated sludge plant effluent have been removed
by plain mixed-media filtration at rates of 5-10 gallons per minute per
square foot.
-------
-------

SECONDARY
TREATMENT

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COAGULATION, SETTLING, AND FILTRATION
-------
-------
-5-
The anticipated effluent quality and the related cost of plain mixed-media
filtration when applied to activated sludge effluent is shown in Table I.
Table I also includes the anticipated effluent quality from tertiary systems
providing higher degrees of treatment in a plant of this size and based upon
a comparison, secondary treatment in a plant of this size and based upon
the same assumptions, would be $80-$100 per million gallons. Of course,
plain filtration alone removes only particulate matter and related BOD and
has no significant effect on soluble organic materials or objectionable
dissolved inorganic material such as phosphates. Dissolved organics may
be reduced greatly by passage of the filter effluent through a column of
granular activated carbon, as shown in Table I. The cost of activated
carbon treatment is based on the assumption that the carbon is regenerated
and reused which is essential to carbon treatment being economically feasible (1)

COAGULATION AND DIRECT FILTRATION

In order to provide an even further clarification of the secondary effluent
and to provide reductions in the phosphate concentration, coagulation of
the secondary effluent can be employed. With mixed-media filtration, it
is possible to apply the coagulated secondary effluent directly to the
filters. By using two filters in series as shown in Figure 5, it is possible
to apply even the very high coagulant dosage required for phosphate removal
directly to the filters. The process shown in Figure 5 is the original
tertiary system used at the South Tahoe Water Reclamation Plant which has
been described in detail elsewhere (1). In this case, the first filter
consisted entirely of coarse coal while the second filter employed coal,
sand, and garnet to provide coarse to fine gradation. The'filter effluent is
very low in suspended solids, BOD, turbidity, and phosphates, as shown
in Table I. However, the filter effluent still contains soluble COD and
color. Again, these soluble organics can be removed by passage of the
filter effluent through columns of granular activated carbon.

If the secondary effluent quality is subject to wide fluctuations, the
reliability of the tertiary system will suffer when direct filtration is
employed. Even the mixed-media filters cannot tolerate suspended solids
concentrations of several hundred mg/1 which may occur during a severe
upset of the secondary plant. To increase the reliability of the system
under these conditions, the use of supplemental settling between the secondary
system and the tertiary system is desirable.

COAGULATION FOLLOWED BY SETTLING AND FILTRATION

A schematic diagram of the process now being used at the South Lake Tahoe
plant, which has recently been expanded from 2-1/2 MGD to 7-1/2 MGD, is shown
in Figure 6. The secondary effluent is chemically coagulated, flocculated,
and then passed through a settling basin, prior to filtration and carbon
treatment. Thus, if the secondary system should upset severely, most of
the biological solids will be trapped in the intermediate settling basin
and will not adversely effect the tertiary system. The coagulant shown
in Figure 6 is lime rather than alum which was used in the original Tahoe
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tertiary plant. The change in coagulant resulted from extensive studies
on the feasibility of recovery and reuse of both alum and lime. No economically
feasible method of alum recovery and reuse could be found, while it was
found that lime could be recalcined and reused (1). The high lime doses
required for phosphate removal raise the pH of the secondary effluent to
such high levels (greater than 10.5) that the ammonia nitrogen in the lime
coagulated effluent may be removed as ammonia gas. This can be accomplished
by passing the high pH effluent through a packed tower in which the ammonia
gas is liberated and stripped from the system by a countercurrent flow of
air. Details of the studies on ammonia stripping have been published elsewhere (1
The stripping tower effluent is recarbonated and then passed through the
filtration and activated carbon systems. As can be seen from Table I,
this system provides an effluent with very low concentrations of suspended
solids, BOD, COD, turbidity, color, phosphate, and nitrogen.

The removal of particulate matter by gravity sedimentation is one of the
most widely used processes in the field of waste, treatment. Investment
in settling tanks represents a significant portion of the total capital
costs involved in treatment facilities. In spite of the importance of this
process, application of the principles involved has progressed so slightly
that design criteria established more than 50 years ago are still in wide
spread use. Settling basin design, for the most part, continues to conform
to previous practice in size and shape with little consideration for the
principles involved. As indicated in the above discussion, gravity settling
is not only important in primary and secondary systems but can play an
important roll in tertiary treatment systems.

Our research program has devoted a great deal of time to develop a method
by which the basic theories of sedimentation can be applied in a practical
manner. This basic theory indicates that the use of very shallow settling
basins would enable the detention time of the settling process to be reduced
to only a few minutes, in contrast to the several hours used in conventional
basins. The basic theory can be readily understood by examination of
Figure 7. This figure is a schematic representation of the cross-section
of an ideal, rectangular, horizontal flow settling basin of depth, ho,
and length, LQ, with the direction of flow being from left to right. The
diagonal dashed line represents the settling path which a particle with
horizontal velocity V and settling velocity vo would take, if it enters at
the top of the basin. This particle would strike the bottom of the basin
with dimensions h and L and would be removed. A particle with a slower
settling velocity, such as vs, would not be removed, but could be if a
false bottom or tray were inserted at depth h. It is apparent that as
basin depth h is reduced even further that basin length L could also be
reduced. This basic theory has been accepted for more than 50 years (2)
and indicates that settling efficiency is independent of basin detention
time and is related only to basin overflow rate and basin depth. In fact,
in 1904, Hazen (2) pointed out that detention times of 10 minutes would
be more than adequate if tray spacings as low as one inch could be provided.
Numerous attempts to apply this theory in the water and waste treatment
field have been made in the last 50 years. The problems which limited
the success of these attempts were sludge removal and flow distribution.
-------
SURFACE AREA A
ho
DIRECTION OF FLOW Q
Lo
FIGURE 7

IDEALIZED SETTLING PATHS OF DISCRETE PARTICLES IN A

HORIZONTAL FLOW TANK
-------
The minimum tray spacing was limited by the space required for insertion
of mechanical sludge removal devices. The wide shallow trays caused flow
distribution problems by their inherently unstable hydraulics. The sub-
stitution of relatively small diameter tubes for the shallow wide trays
overcomes these problems.

Longitudinal flow through tubes with a diameter of a few inches offers
theoretically optimum hydraulic conditions for sedimentation. Such tubes
have a large wetted perimeter relative to the wetted area and thereby provide
laminar flow conditions as evidenced by very low Reynolds numbers.

For example, a one-inch diameter tube, 4 feet long, through which water is
passed at a rate of 10 gpm per square foot of cross-sectional area would
have a Reynolds number of 24, an equivalent overflow rate of 235 gpd per
square foot, and a detention time of only 3 minutes.

Perhaps the manner in which the tube settling device functions can be most
easily understood is by studying Figure 8, in which four demonstration tube
settlers are pictured. The particular tubes shown in Figure 8 are
1-inch diameter, 2 foot long, plexiglass tubes through which flow is passing
from left to right. The influent consists of an alum coagulated raw water
with an initial turbidity of 300 Jackson Units. The total detention time
in the tube settling apparatus is 3 minutes with a velocity of 0.011 feet
per second in each tube. The upper tube in the photograph has just been
placed in service. The sludge deposit near the entrance to this tube has
built up to the point where the velocity in the small inner space between
the top of the sludge deposit and top of the tube is too great to permit
a greater depth of sludge deposit. The second tube from the- top has been
operating for a longer period and the sludge deposits have 'filled a greater
portion of this tube. In these particular tubes, the floe must fall an
inch or less to be removed from the system and, of course, this requires
much less time than it would for the floe to fall the several feet required
in a conventional settling basin. The bottom two tubes have been running
for longer tine intervals and it can be seen that essentially the entire
tube volume is used for floe removal and floe storage before any significant
carryover of floe begins to occur.

The method of sludge removal is very simple and eliminates the requirement
for mechanical sludge removal equipment. The tubes are inclined upwardly
slightly in the direction of flow. Periodic draining of the tube reservoir
has been found to be adequate for sludge removal. As the reservoir is
drained, the water level falls at such a rate that it hydraulically scours
the sludge deposits from the tubes. These slightly inclined tubes are
generally operated in conjunction with a filter so that the volume of water
drained from the tubes during the sludge removal process may be replaced
by a portion of the filter backwash water. A detailed discussion of the
tube settling process can be found elsewhere (3, 4). The method of operation
of the tube settling system should become clear as we examine some waste
treatment systems in which it has been integrated.
-------
-10-
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Figure 8
* TUBE SETTLERS
-------
-11-
EFFLUENT POLISHING

Figure 9 shows an effluent polishing process in which the tube settling
principle has been utilized. The particular system shown provides polishing
of the effluent from a package sewage treatment plant. These small package
plants frequently suffer from periodic discharge of high suspended solids
concentrations in the plant effluent. These plant upsets may result from
inadequate sludge wasting by the plant operator, surges in hydraulic flow
through the plant, or failure of the plant sludge collection and return
system. The package plant effluent is collected in a sump and then pumped
through a tube settling unit followed by mixed-media filtration. The filter
effluent is collected in a storage tank and is used for backwashing the
filter. The backwash storage tank also serves as a chlorine contact basin.
The role of the tube settler in the process shown in Figure 9 is that of
a supplemental solids separation device which allows the filter to continue
to operate efficiently even during severe upsets of the package sewage
treatment plant. During such upsets, any attempt at direct filtration
of the package plant effluent would meet with failure due to rapid blinding of
the filter surface with the extremely high solids concentrations encountered.
During such an upset, using the system shown in figure 9, the bulk of the
solids contained in the package plant effluent will be removed in the tube
settler and the clarified tube settler effluent will then be amenable to
mixed-media filtration. When the sludge storage capacity of the tube settler
is exhausted, a significant amount of floe carryover will rapidly occur
and cause the headloss on the filter to increase to a point such that the
backwashing cycle is automatically initiated by filter headloss. During
the backwash cycle, filter effluent is withdrawn from a backwash storage
tank, passed up through the mixed-media filter, and recycled to the aeration
tank. At the same time, the drain valve on the tube settler is opened
and the entire contents of the tube basin drain into the sludge holding
tank. The solids captured in the tube settler are completely scoured from
the tubes during this draining cycle. Prior to the end of filter back-
washing, the last portion of filter backwash water is diverted into the
tube reservoir to replace the water drained from the basin. As soon as
the 7 minute cleaning cycle is coinpleted, the polishing unit is immediately
returned to service. During the cleaning cycle, the incoming sewage flow
is stored in the collection sump along with the backwash water recycled
to the system.

Detailed data on such a polishing unit have been published (5) and show
that such a system will produce average effluent suspended solids and BOD
of less than 5 mg/1. The polishing process continues to function efficiently
even though the solids concentrations in the package plant effluent may
be in excess of 2,000 mg/1. Operational data from a 20,000 gpd system
which has been in operation for over one year at a U.S. Forest Service
installation in Oregon (6) show that the periodic heavy solids losses normally
encountered in a package plant installation can be completely eliminated
by use of this polishing process. Data from this Forest Service installation have
also shown that in addition to providing very low BOD and suspended solids
concentrations, the low turbidity of the polishing process effluent allows
very effective disinfection. Coliform concentrations of less than 2 per
100 ml are routinely achieved. Of course, the extremely short residence
times in the tube settlers make the polishing process a very compact unit
which occupies a very small portion of land compared to the secondary process.
-------
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Phosphate removal can also be achieved in a packaged polishing system using
the tube settling, mixed-madia filter combination. Such a system is shown
schematically in Figure 10. In this system, the effluent receives alum
coagulation and flocculation prior to entering the tube settler. As in
the polishing process described above, the very low residence times, (less
than 15 minutes) in the tube settling reservoir allow very compact tertiary
systems to be manufactured. This is well illustrated by the plant pictured
in Figure 11. This is a 100 gpm plant providing flocculation, sedimentation,
and filtration with a total plant residence time of less than 30 minutes.
The overall plant dimensions are 6 feet by 6 feet by 14 feet. A 30,000
gpd plant similar to that pictured in Figure 11 has been in operation for
several months at a Federal Water Pollution Control Administration project
in Minnesota. Effluent quality shown in Table 1 for coagulated and filtered
secondary effluent is readily achieved in this package system.

CLARIFICATION OF MIXED LIQUOR

The tube settling systems described thus far have all employed tubes inclined
only slightly upwardly in the direction of flow so that they may be cleaned by
periodic drainage. As has been described above, the tubes are generally
used in conjunction with a filter so that the volume of water drained during
the sludge cleaning cycle can be replaced by a portion of backwash water.
During tests of the effects of angle of tube inclination it was found that
if the tubes were inclined steeply enough, the solids which settle to the
bottom of the tube will slide downward along the tube bottom and eventually
exit the tube. It has been found that at angles in excess of 45 degrees,
a natural evacuation of the solids can be achieved continually without
interupting the flow through the tubes. A countercurrent flow pattern
is established in which particles entering the tube are carried upwardly
until they settle to the lower tube surface at which point they become
trapped in a downward flowing stream of concentrated solids. The advantages
of such a self-cleaning high-rate sedimentation device are apparent.

One application of interest is the separation of the high mixed liquor
solids levels encountered in activated sludge systems. Figure 12 is a
schematic diagram of a pilot plant used to evaluate the steeply inclined
tubes for continuous separation of mixed liquor. Comminuted raw sewage
was aerated with the resulting mixed liquor passing through a tube settling
basin with a total detention tine of less than 15 minutes. The tube effluent
was then passed through a mixed-media filter for further polishing. It
was found that the tube settler provides very efficient separation of the
mixed liquor solids as well as a continuous gravity return of the solids
to the aeration basin. Mixed liquor solids in excess of 7,000 mg/1 have
been maintained with the system shown in Figure 12. The tube settler effluent
solids have averaged about 40 mg/1. Filtration of the tube settler effluent
consistently reduces the solids and BOD to less than 5 mg/1.

A prototype of a package system incorporating the essential features of
Figure 12 has been in operation for several months. An aeration time of
12 hours, a tube settling detention time of 15 minutes, and an average
filtration rate of 5 gpm per square foot have been used. A reduction in
aeration time over that used in conventional extended aeration package
plants allows the very high quality effluent to be produced from an integrated
package of smaller size than a conventional package plant of the same capacity.
For example, a 20,000 gpd extended aeration plant would occupy 42 feet
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by 10 feet. 'A 20,000 gpd plant providing 12 hours aeration, tube settling,
mixed-media filtration, backwash storage and chlorine contact, and sludge
storage within one package module would occupy only 25 feet by 10 feet.
Both plants have a depth of 10 feet. The dimensions of the extended aeration
plant do not include the area required by sludge storage facilities provided,
nor the area required for chlorine contact. Thus, the integration of
high-rate sedimentation and filtration technology enable the design of very
compact treatment systems which provide a higher degree of reliability
and a higher degree of effluent quality than conventional systems while
occupying less space.

Another system into which the steeply inclined, self-cleaning tube settler
has been integrated is shown in Figure 13. The quality of effluent obtainable
from a trickling filter plant is often limited by the failure of the filter
to efficiently remove soluble BOD. Removal of this soluble BOD can be
achieved by activated sludge treatment of the trickling filter effluent.
The system shown in Figure 13 is designed to accomplish this removal within
the confines of the existing secondary clarifier. This is achieved by
converting the existing secondary clarifier to an aeration basin and including
a steeply inclined tube settler within the existing basin. The very small
volume required for solids separation in the steeply inclined tube settler
allows both the necessary aeration time and sedimentation time to be provided
within the existing basin. A 150,000 gpd plant has been converted to this
process and has been in operation for several months. The data from this
operation have been reported in detail (4). This operation has shown the
complete removal of soluble BOD to be achieved in the modified clarifier
which provides 1-1/2 hours of aeration and 10 minutes of settling in the
steeply inclined tubes. The suspended solids escaping the inclined tubes
in this application have averaged 30-40 mg/1. Subsequent'filtration, as
provided in the pilot filter shown in Figure 13, reduces the suspended
solids and BOD to less than 5 mg/1. The integration of the tube settler
into this system allows the efficiency of a trickling filter plant to be
upgraded from the norm of 85 percent to more than 95 percent with the only
additional area required being that for the relatively small space occupied
by a mixed-media filter. Solids in the aeration zone of the modified clarifier
have been 2,000-4,000 mg/1 during these tests.
-------
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-------
-19-
REFERENCES

1. Slechta, A. F. and Gulp, G. L., "Water Reclamation Studies at the
South Tahoe Public Utility District." Water Pollution Control
Federation Journal, 39, 5, page 787 (1967).

2. Hazen, A. "On Sedimentation." Transactions of American Society of
Civil Engineers, 53, page 45 (1904).

3. Hansen, S. P. and Gulp, G. L., "Applying Shallow Depth Sedimentation
Theory." American Water Works Association Journal, 59, 9, page 1134
(September 1967).

4. Hansen, S. P., Gulp, G. L., Stukenberg, J. R., "Practical Application
of Idealized Sedimentation Theory." A paper presented at the 1967
Water Pollution Control Federation Conference, New York City, (10
October 1967).

5. Gulp, G. L. and Hansen, S. P., "Extended Aeration Effluent Polishing
by Mixed-Media Filtration." Water and Sewage Works, page 46 (February 1967),

6. Gulp, G. L. and Hansen, S. P., "Field Experience in Polishing Package
Sewage Plant Effluent", Public Works (In press).
-------
THE DOW CHEMICAL COMPANY
CHEMICALS BUILDING
2020 ABBOTT ROAD CENTER
MIDLAND, MICHIGAN 4864O
THE DOW PROCESS
FOR
PHOSPHORUS REMOVAL

RONALD F. WUKASCH
for the
FWPCA PHOSPHORUS REMOVAL SYMPOSIUM
CHICAGO, ILLINOIS
JUNE 1968
-------
TABLE OF CONTENTS
Pa<
i

Introduction 1
Process Description 1
Application 3
Plant Scale Data 3
Gray!ing,Michigan ' 3
Lake Odessa, Michigan 6
Chemical and Physical Requirements 10
Metal Requirements 10
Flocculation Requirements 11
Reaction Time Requirements 11
Cost of Process 12
Conclusions 15
References 16
Appendix 17
-------
THE DOW PROCESS FOR PHOSPHORUS REMOVAL

by: Ronald F. Wukasch
Environmental Engineer
The Dow Chemical Comoany
Midland, Michigan
Introduction
Late in 1966, The Dow Chemical Company instituted a program which
sought to develop a phosphate removal process compatible with both
the activated sludge and trickling filter processes. For several
reasons, a chemical rather than a biological approach to phosphoru
removal was selected for study, not the least of which is the
reservoir of strength in chemical processes within the company.

Process Description
Chemical phosphorus removal techniques involve the conversion of
soluble phosphorus into an insoluble form by precipitation or
adsorption. This can be accomplished by the addition of metallic
salts to the wastewater to form slightly soluble metal phosphate
compounds, or by increasing the pH of the wastewater with lime
or other strongly basic materials to cause the formation of
insoluble calcium phosphate salts.

Precipitation of soluble phosphorus to the insoluble form, however,
does not complete a phosphorus removal process. The resulting
precipitates are extremely fine and well suspended. Without further
treatment, these fine phosphorus precipitates resist removal by
sedimentation. Accordingly, an effective chemical phosphorus remova'
process must have two essential steps.

1, The conversion of soluble phosphates into an insoluble,
suspended form, and
2. The permanent removal of the suspended phosphate from
the waste stream.
-------
-2-

The first step, the conversion of soluble phosphates to insoluble,
suspended phosphates, is accomplished with the addition of small
quantities of metallic salts. (Figure 1) Ferrous, ferric, and
aluminum salts are all effective.

The second step is the removal of the insoluble phosphorus from
suspension. Under normal conditions, only 10 to 15 percent of
these extremely fine solids can be removed by sedimentation.
However, these suspended metallic phosphates can be flocculated
with suitable organic polyelectrolytes. For example, the sus-
pended phosphate particles formed by the addition of ferric
chloride or sodium aluminate, are readily coalesced into large,
well-settling floes with an ionic organic polyelectrolytes. The
completeness of flocculation or solids capture of these systems
is excellent and the settling rate of the flocculated material
is rapid.

The colloidal suspension formed by the addition of a small quantity
of ferrous chloride requires modification by the addition of a
strong base before it can be readily flocculated with organic poly-
electrolytes. The transient strong base alkalinity modifies the
colloidal properties of the system. It is not a pH associated
phenomen a.

Typically the chemical requirements for the ferrous chloride
system are 10 to 25 mg/1 FeCl2 as Fe, 30 to 40 mg/1 of strong
base alkalinity as CaC03 (24 to 32 mg/1 of NaOH or 17 to 22 mg/1
CaO), and 0.3 to 0.5 mg/1 of Purifloc® A-23, a high molecular
weight an ionic polyelectrolyte.
-------
-3-
Appl1 cation
The three choices for plant-scale use of this chemical system
are in primary sedimentation, secondary clarification, or
a tertiary sedimentation system. Use of the process in primary
sedimentation promises the greatest benefits for the reasons
descri bed in Table 1.

Plant Scale Data

Grayling. Michigan - The process was demonstrated full-scale
at two Michigan sewage treatment plants during the summer of 1967.
The first of these studies was conducted over a period of three
months at the Grayling, Michigan, waste treatment plant which
provides primary treatment for a flow of about 0.3 MGD. As shown
in Figure 2, the average chemical dosages were 15 to 25 mg/1
FeCl2 as Fe, 30 to 50 mg/1 NaOH as CaC03, and 0.3 mg/1 of
an ionic polyelectrolyte. During the trial the plant was heavily
overloaded hydraulically due to the seasonal influx of tourists
and a National Guard summer encampment. In addition, no attempt
was made to proportion the chemical feed rates to the variations
in flow at the plant, and consequently chemical dosaqes were
either above or below ootimum most of the time. Despite these
adverse circumstances, total phosphorus removal ranged between
60 and 80 percent with a mean of 72 percent as shown in Table 2,
Suspended solids removal was increased by 27 percent to an average
of 78 percent. BOD removal increased from 40 percent to 58 percent
during this study. The process is being installed more permanently
at this plant and will be operational as of June 1968.
-------
-4-

BENEFITS OF PHOSPHATE REMOVAL IN PRIMARY TREATMENT

*Process applicable in both activated sludge and trickling
filter plants .

*Secondary biological treatment provides "polishing" for further
phosphate removal.

*Increased removal of SS and BOD in primaries.

*Reduced loading to secondary
*Improved final effluent quality
*Reduction of waste activated sludge or
trickling filter humus

*Increased ratio of primary sludge to secondary
si udge
*Higher concentration digester feed
*Improved sludge dewatering
*Lower total volumes of sludge to be handled
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Lake Odessa, Michigan - The second plant scale test was performed
over a three-month period at Lake Odessa, Michigan, with a flow
of 0.5 MGD (Figure 3). Here the treatment facilities included
primary sedimentation, a trickling filter, and sludge digestion
with the digester supernatant returned to the primary clarifiers.
Chemical dosages averaged the same as used in the Grayling study
with no attempt made to proportion chemical feed rate to plant
flow. With chemical treatment, total phosphorus removal ranged
from 75 to 93 percent with a mean value of 82 percent. (Table 3)
Overall plant suspended solids removal and BOD removal were
also substantially improved.

Mixing and flocculation were much less than required for maximum
process efficiency, and physical modifications of the plant
could be expected to substantially increase the effectiveness
of the process. Permanent installation of the process which
requires modifications is currently under design.

The phosphorus concentration in the returned dfgester supernatant
decreased during the period of this study. Initial supernatants
contained 100 to 200 mg/1 of phosphorus. There was an average
of 23 mg/1 total phosphorus in the supernatant during the latter
portions of the chemical treatment. It was apparent from this
that phosphorus release was not occurring during digestion
Additional proof was obtained when a crystalline phosphate pre-
cipitate, vivianite (Fe^PO,)~•SH^O was identified in the digested
sludge from Lake Odessa and also in the Grayling undigested
primary sludge by x-ray diffraction techniques. (Table 4) The
quantitative elemental analysis by x-ray fluorescence of these
two sludges is displayed in Table 5.
-------
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Table 4
SLUDGE ANALYSES : PHOSPHATE REMOVAL

Ferrous Chloride - Hydroxide - Polyelectrolyte Process

Qualitative Analysis: (X-ray Diffraction)

Grayling Primary Sludge:
Major Const: Vivianite; Fe3(P04)2'8H20
Minor Const: Quartz; Si02
o
Unidentified line at 16 A

Lake Odessa Mixed Primary and Humus:
Major Const: Vivianite; Fe3(P04)2 • 8H20
Minor Const: Quartz; SiO,
-------
-9-
Table 5
SLUDGE ANALYSES : PHOSPHATE REMOVAL
Ferrous Chloride - Hydroxide - Polyelectrolyte Process

Quantitative Analysis: (X-ray Diffraction)
Percent
Element Grayling PrimaryLake Odessa Mixed
Pb -
Ba 0.12 .02
Sn .01
Cd
Ag .01
Sr
Zn
Ca
Fe
Mn
T1
Ca
K
Cl
S
P
Si
Al
.23
.14
20.2
.08
.11
8.1
.4
1 .1
3.1
5.1
.4
.8
.24
.1
23.6
.06
.1
6.0
.8
2.1
3.0
6.8
4.0
.8
-------
-10-
Since the use of this process in primary treatment significantly
increases suspended solids removal from the raw sewage, the
quantity of primary sludge produced in a plant is increased by
additional sewage solids as well as phosphate solids Thus, it
is difficult to tell directly how much additional non-volatile
sludge solids can be directly attributable to the chemical process
However by estimating that 5 mg/1 of additional phosphorus will
be removed as vivianite with the remaining iron being removed
as the hydroxide, it can be estimated that approximately 300
pounds of additional inorganic sludge solids will be produced
per million gallons. The sodium or calcium added to the waste
as alkalinity remains in solution.

The plant scale studies at Grayling and Lake Odessa were conducted
in cooperation with the Michigan Department of Public Health
Copies of the joint reports that have issued from these studies
M ?}
are available- u ''
... ts_ • The removal of total phosphorus from the
waste stream is limited by the thoroughness to which the soluble
phosphorus has been converted to insoluble phosphorus (Step 1)
The degree to which soluble phosphorus is insolubilized obviously
depends on the metal dosage The quantity of the metals which
must be added to achieve certain results in terms of final ortho-
phosphate concentration in the waste stream can be predicted as
shown in Figures 4 through 7 These data represent laboratory
studies at 11 different waste treatment plants in Michigan and
Ohio with varying degrees of industrial components- These curves
show that the amount of metal that must be added per unit of
phosphorus removed from solution regresses is a function of
the desired final ortho-phosphate concentration . This functional
relationship does not describe the removal mechanism, since
both adsorption and precipitation phenomena fit the same model,
-------
-11-
However, these relationships are useful in predicting the metal
dosages required to achieve certain results in phosphorus removal.

Flo ecu!at ion Requirements - Having vaccomnlished the insolubili-
zation of the soluble phosphorus present in the waste stream,
the problem now becomes removing it from suspension (Step 2).
As stated previously, these extremely fine colloidal precipitates
settle poorly and require chemical flocculation to permit removal
by sedimentation. This process requirement of flocculation
is shown quantitatively in Figures 8 through 11. The experimental
procedure used to generate these data is a modified jar test con-
ducted en one liter samnles in 1500 ml beakers on a Phipps and
Byrd gang stirrer. A 5 minute final settling period, under dynamic
(stirred) conditions, was used to represent sedimentation tank
performance.

In each of these systems, chemical flocculation of the precipitated
phosphorus is reouired to achieve satisfactory total phosphorus
removal. The alum and poly electrolyte system has' shown a highly
erratic response on certain wastes, even with alkalinity adjust-
ments.

Reaction Time Requirements - There is a reaction time criticality
between the addition of the metallic ions and poly electrolyte
addition.

As shown in Figures 12 and 13 for the case of ferrous iron and
sodium aluminate, a minimum irtevening mixing period of approx-
imately 4 minutes is required between inorganic chemical addition
and organic polyelectrolyte addition. This type of response
is also the case for ferric iron and alum. Apparently, this
reaction time is not necessary to the insolubilization of the
dissolved phosphorus since the ortho-phosphate disappearance is
almost immediate upon the addition of the metal. Presumably a
-------
-12-

change in the colloidal system is occurring during this inter-
vening mixing period which results in a suspension much more
responsive to anionic polyelectrolyte flocculation.

Table 6 presents a summary of the operational requirements, based
upon the preceding studies, that must be met to successfully
apply this process for phosphate removal.

Cost of Process
A cost summary of the various modifications of the process is
shown in Table 7. The basis for these cost figures is shown
in the appendix.

The chemical costs quoted are representative, fair price per
pound figures. Local conditions, shipping distances, and other
factors will affect these nominal prices. In addition, variations
in the quantity of phosphorus and response of the waste stream
from city to city will alter chemical requirements.

The total cost of the capital equipment is not very sensitive
to the size of the plant. The capital costs shown are based
on the equipment required for a plant treating between 50 and
100 MGD. One key piece of equipment is an automatic ortho-
phosphate analyzer used to control the metal salt dosage on a
continuous basis. The iron or aluminum dose must be at correct
ratio to produce the desired residual ortho-phosphate. Too
low a dosage reduces the effectiveness of phosphate removal;
too high a dosage is uneconomical and it will result in iron or
aluminum carry-over in the plant effluent,

A modest reduction In overall sludge handling costs can be
expected, Although some additional Inorganic solids are being
produced 1n the process, the reduction of secondary sludge due
to Improve primary sedimentation efficiency represents a real
cost savings 1n terms of digester volume and dewatering costs,
-------
-------
-13-

SUMMARY OF PHYSICAL REQUIREMENTS

PHOSPHATE REMOVAL PROCESS

I. Add metal salts to the raw sewage with thorough

A. With Fed,,, add base not less than

10 seconds later.

II. Allow reaction to proceed for a minimum of five

III. Add A-23 organic polyelectrolyte.

A. Flash mix 20 to 60 seconds.

IV. Mechanical or air flocculation; 1 to 5 minutes

V. Gentle delivery of flocculated sewage to

sedimentation tanks.
-------
-14-
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CONCLUSIONS
1. A two step process consisting of
1) Converting soluble phosphate to suspended phosphate
with iron or aluminum salts.
2) Removal of the suspended phosophate and other solids
by chemical flocculation and sedimentation
has been demonstrated to be an effective method for
phosphorus removal.

2. Practice of the process in primary sedimentation results
in greatly improved suspended solids and BOD removal in
primary treatment with corresponding plant-wide benefits

3. With minor physical modifications, the process can be
integrated into virtually any waste treatment plant.

4. The total cost of the process for various chemical
systems can range from $25 to $60 per million gallons
treated.

5. The system using ferrous chloride, alkalinity and an
an ionic polyelectrolyte is the most economical variation
' of the process with a total cost of less than $30 per
million gallons treated.
-------
-16-
REFERENCES
1. "Studies on Removal of Phosphates and Related Removal of
Suspended Matter and Biochemical Oxygen Demand at Grayling,
Michigan, March-September 1967," Otto Green, Fred Eyer,
and Donald Pierce, Division of Engineering, Michigan
Department of Health and The Dow Chemical Company.

2. "Studies on Removal of Phosphates and Related Removal of
Suspended Matter and Biochemical Oxygen Demand at
Lake Odessa, Michigan, May-October, 1967." Wastewater
Section, Division of Engineering, Michigan Department of
Health and The Dow Chemical Company.
-------
-17-

APPENDIX
Chemical Costs

I. Ferrous Chloride: FeCl2
Assume 4 mg/1 orthophosphate as P reduced to 0.3 mg/1
Requires 4.0 mg Fe(II)/mg P.

4.0 mg Fe/mg P x 3.7 mg/1 P = 15 mg/1 Fe(II)
15 x j^7- = 37 mg/1 FeCl2
= 308 Ibs/MG FeCl2
b = S12.30/MG
II. Ferric Chloride: FeCl3
Assume 4 mg/1 orthophosphate as P reduced to 0.3 mg/1
Requires 10.9 mg Fe(III)/mg P.

10.9 mg Fe/mg P x 3.7 mg/1 P = 40 mg/1 Fe(III)
40 x ]6h5 = 116 mg/1 FeCl,
00 *5 *
= 970 Ibs/MG
@ 4eVlb = $38.80/MG

III. Sodium Aluminate:
Assume 4 mg/1 orthophosphate as P reduced to 0.3 mg/1
Requires 6.2 mg Al/mg P.

6.2 mg Al/ml P x 3.7 mg/1 P = 23 mg/1 Al
23 x ? /i J °A ] = 96 mQ/1 Na2Al204-3H20
= 800 Ibs/MG
(3 6£/lb = S48.00/MG
-------
-18-
IV. Sodium Hydroxide: NaOH
28 mg/1 NaOH = 234 Ibs/MG
@ 3<£/lb = $7.00/MG
V. Lime: CaO
20 mg/1 CaO = 167 Ibs/MG
@ U/lb = $1.67/MG

VI. Dow Purifloc A-23
0.5 mg/1 =4.17 Ibs/MG
@ $1 .35/15. = $5.65/MG
(Truck load quantities)
-------
-------
-19-

Capital Equipment Costs

(Treating 50 to 100 MGD)

I. INORGANIC CHEMICAL STORAGE AND HANDLING
FeC12 or CaO or

FeC13 NaOH N*2A12°
A) GENERAL (Total) $ 4,975 $ 3,595 $ 4,045

B) PIPING (Total) 6,620 4,045 660

C) EQUIPMENT (Total) 16,000 8,700 25,000

D) ELECTRICAL REQUIREMENTS gQO 2JQO 40Q
( lo t a I )

TOTAL DIRECT COST $28,495 " $18,440 $30,105

TOTAL including
Overhead, Profit, $37,200 $24,000 $39,200
and Engineering (30%)

Cost per million gallons
-------
-20-
Operating and Maintenance Costs
(50 MGD Plant)
I. MANPOWER
A. Technical:
Assume 1 man full time
$12.000 _ *n ,fi/Mr
50 MGD x 365 Days ' $0.66/MG

B. Operator and Maintenance
1. FeCl2:NaOH:A-23 system
FeCl3:A-23 system
Na2Al204:A-23 system

Assume 1 man shift per day
= $0.60/MG
2. FeCl2:CaO:A-23 system

Assume 3 man shifts per day
$90
50 MGD
$1 .80/MG
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FIG 2

PHOSPHATE REMOVAL PROCESS
GRAYLING, MICHIGAN

PURIFLOC A-23 03mg/L

CD FLOCCULATOR (?)
FERROUS CHLORIDE
ISmg/lFe
/ALKALINITY
/ 30mg/l NaOH
PUMP
STATION
SETTLING
TANKS
Clz
CHLORINE
CONTACT
TANK
FERROUS CHLORIDE
25mg/lFe
ALKALINITY
30mg/l PURIFLOC
NoOH A-23
I |04mg/l
FIG 3

PHOSPHATE REMOVAL PROCESS
LAKE ODESSA, MICHIGAN
1967
TRICKLING
FILTER
PRIMARY
SEDIMENTATION
FINAL
CLARIFICATION
PLANT
INFLUENT
PARSHALL
FLUME
PRIMARY SLUDGE
., SECONDARY
SLUDGE
SUPERNATANT
FINAL
EFFLUENT
SLUDGE
-------
-------
20,,

6
5
4
INSOLUBILIZATION OF ORTHO PHOSPHATE WITH
FERROUS CHLORIDE FeCl2
-0.33
mg/l Fe (H) ADDED
mg/l PHOSPHOROUS INSOLUBILIZED
05 07 O.I 0.2 0.3 04 0.6 0.8 10 2.0
FINAL ORTHO PHOSPHATE'mg/l AS PHOSPHOROUS
30
20

INSOLUBILIZATION OF ORTHO PHOSPHATE WITH
FERRIC CHLORIDE FeCl3
mg/l Ft
mg/l PHOSPHOROUS INSOLUBILIZED
05 07 01 02 0304 060810 20
FINAL ORTHO PHOSPHATE• mg/l AS PHOSPHOROUS
30
-------
-------
FIGURE 6

INSOLUBILIZATION OF ORTHO PHOSPHATE WITH
ALUM' A12 (S04)3 'X H20
mq/1 ALUMINUM ADDED
mg/l PHOSPHOROUS INSOLUBILIZED
I I
OS .07 01 0.2 0.3 04 0.6 0.8 1.0
FINAL ORTHO PHOSPHATE' mg/l AS PHOSPHOROUS
2.0
3.0
20

INSOLUBILIZATION OF ORTHO PHOSPHATE WITH
SODIUM ALUMINATE =
3 H20
Y = 3.7 X
r = 090
-043
mg/l ALUMINUM ADDED
mg/l PHOSPHOROUS INSOLUBILIZED
1 i l i
I
05 07 01 0.2 03 04 06 0.8 10 2.0
FINAL ORTHO PHOSPHATE•mg/l AS PHOSPHOROUS
3.0
-------
-------
FIGURE 8

PHOSPHOROUS REMOVAL WITH IRON n SYSTEMS

Additional alkalinity plus an organic polyelectrolyte are needed

to remove the suspended phosphates by sedimentation
FP (H) + 30mg/l -oO + 05mg/l A23
mg/l TOTAL PHOSPHOROUS

IN OVERHEAD
5 10 15 20 25

FERROUS CHLORIDE , Fed ' mg/l Fe(O)
FIGURE 9

PHOSPHOROUS REMOVAL WITH IRON IT SYSTEMS

Organic polyelectrolyte is required to flocculate & settle

the suspended phcspnctes
10 r
TOTAL PHOSPHOROUS
IN OVERHEAD
5 10 15 20 25

FERROUS CHLORIDE, FeCl : mg/l Fe(EI)
30
-------
FIGURE 10
PHOSPHOROUS REMOVAL WITH ALUMINATE SYSTEMS

An organic polyelectrolyte is needed to flocculate fi settle
the insoluble phosphate formed by the addition of sodium
oluminate.
AlOi
4 -
2 -
mg/l TOTAL PHOSPHOROUS
IN OVERHEAD
5 10 15 20 25
SODIUM ALUMINATE, No2 A1204 • 3H20 mg/l Al
30
FIGURE II

PHOSPHOROUS REMOVAL WITH ALUM
SYSTEMS
Organic polyelectrolyte is needed to flocculate 8 settle
the suspended phosphates
10
Al+*' + 05 mg/l A-23
mg/l TOTAL PHOSPHOROUS
IN OVERHEAD
10 15 20 25
ALUM . A12(S04)3 !8H20-mg/lAl
30
-------
FIGURE 12
REACTION TIME REQUIREMENTS *
IRON (O) SYSTEM

The iron (n) a alkalinity must be added to the waste water jt
least 4 minutes before the organic polyelectrolyte
2 -
RAW SEWAGE TREATED WITH
FERROUS CHLORIDE •
I5mg/l Fe**

LIME ' 30mg/l CaO

PURIFLOC A-23'0.5 mg/1
mg/l TOTAL PHOSPHOROUS
IN OVERHEAD
I 2 3 4. 5
MINUTES BETWEEN! INORGANIC CHEMICALS
ADDITION 8 ORGANIC POLYELECTROLYTE ADDITION
30
FIGURE 13
REACTION TIME REQUIREMENTS'
ALUMiNATE SYSTEM
After the jac*iticn cf sooium alummjte.u minimum cmoun+ i ." inter*
veninj mixing is required before the phosphate contai-'-g collcids
Cj i r> completely flocculated 8 settled
RAW SEWAGE TREATED WITH
SCDIU.V ALUMIMATE:
15 mg/l Al
PURIFLOC A-23 0 b mg/l
mg/l TOTAL PHOSPHOROUS
IN OVERHEAD
I
I234
VINUTES BETWEEN ALU' INATE
ADDITION 3 ORGAMIC PCLYfLE^TRULYTE
-------
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in
n
1 > I ' I
yjjyjii
IZ3I
Ml

lMi..' '} '.10111/1111 i
FULUER COMPAMY / GENERAL AMERICAN TRANSPORTATION CORPORATION

INFILCO PRODUCTS P O, BOX 5O33. TUCSON. ARIZONA SS7O3 TELEPHONE BOS/S23-5-3O1
GATX
©
-------
,NF,UCO
GATX
—-"====:rr0
Mr. Company President, Mayor
or ConsuHing Engineer
Lake Michigan Area
Subject: Water Pollution Problems of Lake Michigan and Tributaries

Dear Sir:
Within the wide scope of corporate activities, many firms (GATX
included) and communities now face the necessity of proper
housecleaning and adequate wastewater treatment to abate pollution

of lakes and streams.
Our \nfilco Products group has specialized in water and waste
treatment for many years. In putting together this brochure we
have attempted to give you an informative "first step" towards wastewater
purification. We hope the following information will prompt you to call
us in for a discussion — without obligation — of your waste
treatment problem, from definition to solution at the least possible cost.

We look forward to hearing from you.
• Sincerely yours,
T E. Meyers
Vice President
Fuller Company
] r
m
;')'
"Discharges of untreated and inadequately treated wastes
originating in Wisconsin, Illinois, Indiana, and Michigan cause
pollution of Lake Michigan which endangers the health and
welfare of persons in states other than those in which such
discharges originate. This pollution is subject to abatement
under the provisions of The Federal Water Pollution Control
Act."
ACTION has been recommended by the Lake Michigan
Pollution Control Conference, the source of the above state-
ment. For municipal wastes, recommended action is to be
taken by December 1972 with respect to higher removals of
BOD and phosphorus. For industrial wastes, the recom-
mended program requires that detailed "action plans" for
adequate treatment be developed by September 1,1968, with
treatment facilities to be constructed by December 1972.
The FuHer Company. Infilco Products group, can help you
define your specific croblam and recommend an QDiimum
-------
f UllEH, liJFIlCO SOlUTIOilS ape tad up..
uUUjJul dulull... with your staff, consulting engineer, and governmental
agency in defining your problem and working out an optimum
solution.

nlluljulu ... in the laboratory to produce the necessary information for
determining and checking design parameters.
Process Selection
. .. which will meet regulatory standards yet prove economical
in first cost and operating cost.
DuliUo... which goes beyond competitive horizons to cover all
phases and types of treatment.

ty lllplilullu UuluuulUII . . . of the correct type and design necessary for efficiency and
economy of process operation. (Only with a. complete line
can an unbiased and cost-saving decision be made; and
Infilco equipment represents the most complete line in the
industry.)

Uui pUi Quo [KpHI lulluo . . . in all phases of water and waste treatment analysis,
process know-how and equipment design.
Installation
. . . facilities are available for erection and start-up on a turn-
key basis when such is desirable.
rilldllullllj... which can be explored on a lease basis with Boothe,
GATX, an affiliate.
Guarantee
... made in accordance with specification and proposal to
assure you of complete satisfaction and compliance.
UU ... continuing service contracts (where desired) to assure
optimum operation and minimum maintenance.
-------
FWPCA has made the following
recommendations for certain
municipalities and industries:
Provide adequate secondary biological
treatment or its equivalent; advanced
waste treatment for phosphate removal;
and substantial reduction of nutrients
which result in undesirable aquatic
growths — by July, 1972.

'- Substantially eliminate pollution from
combined sewers by July, 1977.
For industrial wastes, FWPCA has
recommended that:
Detailed action plans for adequate treatment
of all industrial wastes be developed
within six months (for specified industries).
•i-W L*)jX-Ll...>^WlS. J.
f. -*ri-^ •^Tf<* f"
m^^'i^^^M^di^.'^^^^
including phosphate
removal, are best accomplished by
the "complete mixing" modification of the
traditional activated sludge process.
The advantages of this approach are
incorporated in the modern
AERO-ACCELATOR® activated sludge unit.
Additional removals and/or "polishing"
of treated effluents are accomplished
economically by conventional or in-depth
using the GREENLEAF filter
control for centralized operation of
multiple filters.
Phosphate is also removed by

Efficient and
economical removals can be obtained by the
new Infilco DENSATOR process which
embodies the principles of high-density,
solids-contact treatment.
THE FOLLOWING SECTIONS
ILLUSTRATE AND DESCRIBE
THE DETAILS OF THE ABOVE
SPECIFIC SUGGESTIONS:
-------
-------
Duuetin M-JJU
The I^FILCO DEBTOR
High-Density, Solids-Contact Treatment Plant
r
FULLER COMPANY /
INFILCO PRODUCTS
.^AIVlSPaPTATiarj
GATX
©
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WHAT'S NEW OR DIFFERENT

ABOUT HIGH-DENSITY,

SOLIDS-CONTACT UNITS?
Typical High-Rate,
Solids-Conisci Uniis
A properly designed high-rate solids-contact
treatment unit incorporates within a single uni-
fied structure the processes of mixing, coagula-
tion and flocculation, floe conditioning, liquid-
solids separation, and automatic sludge removal.
Raw water and chemicals are mixed in the pres-
ence of previously precipitated solids which have
been retained in the treating unit. Chemical reac-
tions are accelerated and colloidal materials
easily coagulated since new andsmallerparticles
agglomerate on the surface of old and larger
ones. The density of the floe particles and their
rate of settling increase in the process. Solids
concentrations of 0.5 to 5 grams per liter can be
obtained in the mixing zone, with normal con-
centrations being 1 to 3 grams per liter.
The advantages and economy of the high-
rate, solids-contact unit have been proven in
both municipal and industrial use, at home and
abroad. Since 1934, the Infilco ACCELATOR&
high-rate, solids-contact unit has been the most
generally accepted design throughout the world.
The DE.NSA70R'Plant
Research and development by Fuller's Infilco
product engineers and chemists has established
that improved treatment results can be obtained
if the solids concentration in the reaction zones
is maintained significantly higher than possible
with conventional solids-contact units. The
DENSATOR plant was designed to provide this
process improvement for applications in which it
is advantageous.
Normally, the solids concentration in the
reaction zones represents the precipitates formed
from 5 to 10 reactions; the DENSATOR unit
utilizes precipitates formed from up to 50 or more
reactions.
The weight of the sludge, after many reac-
tions, increases much more rapidly than its vol-
ume. This densification of the sludge is accom-
panied by rapid settling characteristics — sludge
solids of 500 grams per liter have been obtained
in the process. Settling rates equivalent to a 4.5
gpm per square foot rise rate have been ex-
ceeded with softening types of sludges.
Page 4
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LIME FEED
RAW WATER
INLET
TREATED
WATER
OUTLET
.SECONDARY
REACT iON ZO'NE
DRAIN
SLUDGE
RECIRCULATION
Cutaway drawing of DENSATOR piant
shows treatment zones
and illustrates the process
High-density, solids-contact treatment
requires special modifications of the accepted
design of existing solids-contact units. New and
improved means of sludge recirculation have
been incorporated to replace conventional hy-
draulic circulation. The primary reaction zone,
in which raw water is mixed with chemicals and
with a controlled volume of recirculated dense
solids, is smaller than in customary solids-con-
tact units. The reaction zone is followed by a
flocculation zone or secondary reaction zone
where the mixing is less intense and where coag-
ulants or coagulant aids may be added. These
two zones are followed sequentially by a third
zone where the major portion of the solids sep-
from the treated water. At the bottom of
sin the high-density solids remain fluidized
under semiquiescent condition. It is from this
zone that the dense solids are recirculated into
the reaction zone.
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TYPICAL
DENSATOR
OPERATING
RESULTS
Plant A—Surface Water: 77°F
Densator
Raw Water Effluent*
Calcium hardness (ppm as CaC03): 120 80
Magnesium hardness (ppm as CaC03): 68 27
M Alkalinity (ppm as CaC03): 126 44
P Alkalinity (ppm as CaC03): 0 32
Solids in sludge blowdown (grams/liter): 60
Plant B —Well Water: 463F
Densator
Raw Water Effluent*
Calcium hardness (ppm as CaC03).- 128 22
Magnesium hardness (ppm as CaC03): 83 26
M Alkalinity (ppm as CaC03).- 264 124
P Alkalinity (ppm as CaC03): 0 76
Solids in sludge blowdown (grams/liter): 75
Plant C —Well Water: 53 F
Densator
Raw Water Effluent*
Calcium hardness (ppm as CaC03): 248 86
Magnesium hardness.(ppm as CaC03): 156 66
M Alkalinity (ppm as CaC03): 308 66
P Alkalinity (ppm as CaCO.,): 0 44
Solids in sludge blowdown (grams/liter): 170
'Filtered prior to analysis
Page6
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Plant D — Combination Well and
Surf ace Water: 80° F
Densator
Raw Water Effluent*
Calcium hardness (ppm as CaC03): 114 26
Magnesium hardness (ppm as CaCOs): 104 22
M Alkalinity (ppm as CaCOa): 208 45
P Alkalinity (ppm as CaCOs): 0 29
Si02 (ppm as Si02): 24 7
Solids in sludge blowdown (grams/liter): 120
Plant E — Final clarifier effluent
from municipal sewage
activated sludge plant

| Total hardness
P Alkalinity (ppm as CaC03):
M Alkalinity (ppm as CaCOs):
Total phosphate (ppm as POJ:
COD (ppm):
Si02 (ppm as SiO:):
Influent
200
0
250
30
60
35
Densator
Effluent*
100
100
150
0.7
50
25
220
I
200
180

60
40
M
P = 0
DAW WATER
- FILTERED WATER -

6 12 6
AM PM
6 12 6
AM PM
6 12
6
PM
6 12 6
AM PM
Intilco DENSATOR plant (center ol photo)
and Infilco ACCELATOR plant (foreground)
soften water at Motorola 'nc
Phoenix, Arizona
Operating results from a Densator with automatic conductivity ratio control of lime feed
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FULLER
ENGINEERED PRODUCTS FOR INDUSTRY...
AIR HANDLING EQUIPMENT . . . Fuller rotary compressors, Sutorbilt blowers and
Lehigh® fans
PNEUMATIC MATERIALS CONVEYING SYSTEMS . . . Airveyor, Airslide* and
Fuller-Kinyon conveying systems
POLLUTION CONTROL EQUIPMENT . . . Dracco5 dust collectors, Infilco water and
sewage treatment systems
HEAVY PROCESSING MACHINERY AND SYSTEMS . . . Traylor crushers, kilns
and mills, Fuller grate coolers, fluid bed reactors and Fuller specialized equipment for
the mineral industries
Offices in principal cities of the United States and Canada ^^ _ ——- —

COMPANY
IIMPILCO PRODUCTS P.O. BOX SO33. TUCSON. ARIZONA S57O3. TELEPHONE 602/633-5401

PRINTED IN U.S.A. i/M 6-63 W
0
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PHOSPHORUS REMOVAL BY HIGH-DENSITY, SCLIDS-CONTACT
TERTIARY TREATMENT

It is conceivable that today's wastewater treatment processes

may eventually yield under the combined pressures of increasingly strin-

gent effluent quality requirements and developing technology to systems

yet unknown. It appears, however, that in the foreseeable future ad-

vanced treatment will largely entail addition of physical-chemical separa-

tion processes to the secondary systems now used (1).

Processes of this type for phosphorus removal comprise application

of precipitation and/or adsorption reactions induced by addition of suit-

able cations to the treated wastewater under proper conditions, followed

iby clarification for suspended solids removal. Practical possibilities

in this regard are largely limited to use of lime and iron or. aluminum

salts, singly or in combination. Numerous studies have shown that any of

these treatments is effective at relatively high dosages. Typical data

for treatment of effluent from a heavily loaded sewage activated sludge

system are presented in Fig. 1(2).

Whereas similar phosphorus reductions are obtained with any of

these chemicals, there are other important considerations. It has been

observed that lime treatment of high-alkalinity wastewaters produces

granular solids which settle, thicken, and dewater readily. Solids from

treatment of low-alkalinity waters are more flocculent. Disposal of the

waste sludge and recovery of usable lime by calcination is practical.
*Director of Research, INFILCO Products Group, Fuller Company, Tucson,
Arizona. (Paper presented at FWPCA Workshop on Phosphorus Removal
Technology (Second Session), Chicago, Illinois, June 26-27, 1968).
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-2-

Further comparison of the treatment possibilities reveals serious

relative disadvantages for the iron and aluminum processes. Chemical

costs are high and the solids produced are light and voluminous. Treat-

ment with either chemical leads to sludge handling and disposal problems

which in a practical sense are as yet unresolved. All things considered,

the lime process is favored currently.

High-density, Solids-contact Treatment

Reaction kinetics favor use of a solids-contact process. Several

years ago, INFILCO initiated a program to develop a new process of this

type with the objectives of lower capital cost, maximum results, and

minimum waste sludge volume. The high-density, solids-contact process is

the result of that program, and the DENSATOR unit is the device in which

the process is applied.

Improved overall treatment results are obtained if the solids

concentration in the reaction zone is maintained much-higher than is

possible in conventional solids-contact units. In most such units the

precipitates from 5 to 10 reactions are carried. The DENSATOR unit utili-

zes the precipitates from up to 50 or more reactions. Other important

advantages accruing from this type of treatment are improved solids settl-

ing characteristics and a significant reduction in waste sludge volume as

a result of the solids densification which occurs after many reactions.

High-density, solids-contact treatment requires special modifica-

tion of the usual solids-contact equipment. Fig. 2 illustrates some of

the features of the DENSATOR unit. The primary reaction zone - in which

the influent wastewater, lime, and a controlled volume of recirculated

dense solids are mixed - is smaller than in customary solids-contact

units. The primary reaction zone is followed by a flocculation or
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-3-

secondary reaction zone where mixing is less intense and where coagulants

or coagulant aids may be added. These two zones are followed sequentially

by a third zone in which solids separation occurs. Fluidized high-density

solids are accumulated in the bottom of the unit and it is from here that

solids are recirculated to the primary reaction zone.

Process Application and Performance

Ten pilot-plant investigations of renovation of treated municipal

sewage involving INFILCO solids-contact units on a 7,000 to 35,000-gpd

scale have been completed or are in progress in this country and overseas.

With the exception of two studies on oxidation pond effluent, this work

was on treated waste from various types of activated sludge plants. In

^dition, a 500,000-gpd DENSATOR unit is being furnished to the Water

Reclamation Research Center at Dallas, Texas, for study of chemical treat-

ment of domestic sewage from any of five sources within the White Rock 2-

stage trickling filter plant, plus effluents from pilot-scale activated

sludge systems. Objectives of these investigations are variable, but all

of this experience is pertinent to phosphorus removal.

Phosphorus removal by the lime process improves with increasing

pH. This is well illustrated in Fig. 3 based on performance data obtained

by Los Angeles County Sanitation Districts at Pomona, California, for

single-stage DENSATOR treatment of activated sludge effluent. Influent

total phosphorus averaged close to 11 mg/1 as P and total alkalinity and

hardness 267 and 204 mg/1, respectively, during this 10-week study. In

this case, it was necessary to raise the pH to about 10.0 to achieve 80

kf cent removal of phosphorus. The hydrated lime dosage for this level

of removal was approximately 280 mg/1. Higher dosages increased phos-

phorus removal to more than 90 per cent. Waste-sludge volume during this

study raneed 0.1-0.5 oer cent nf t-Vio f-Viv/iiioVir."*-
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-4-

With the possible exception of small plants, the pH of lime-

treated effluents may be too high for direct discharge. Adjustment of

pH, probably by recarbonation, will be necessary when the buffer capa-

city of the receiving stream is insufficient.

The lime demand of treated sewage varies with changes in the

sewage composition and is of course influenced by the alkalinity, being

relatively high when alkalinity is high and lower when the alkalinity is

less. The quantity required to attain a given pH can be quite variable,

as the Pomona data of Fig. 4 show. Because phosphorus removal is pH-

dependent, this is important in terms of process control. Flow-propor-

tioned dosage control leaves something to be desired and pH-controlled

lime feed involves undesirable control problems, cost and maintenance.

In this connection, the double reaction-zone design of the DENSA-

TOR unit enables split treatment and use of a simple and inexpensive auto-

matic ratio control for lime feed when the influent wastewater contains

sufficient alkalinity and calcium hardness. In this process (Fig. 5) a

portion of the influent is introduced into the primary reaction zone with

a high concentration of recycled solids for rapid completion of reactions

at high pH. Excess hydrate alkalinity in proportion to influent alkalinity-

is maintained in this zone by lime fed under conductivity ratio control

and "recarbonation" is accomplished in the secondary reaction zone with the

remaining fraction of influent flow. When a DENSATOR unit is coupled with

automatic ratio control of lime feed, the lime system can be greatly

The effectiveness of each of these control systems is under study

at the FWPCA-DC demonstration facility at the Blue Plains treatment plant

in Washington, D.C.
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-5-

As the costs of new water supply and wastewater treatment for

disposal coverge, reuse potentials for the treated wastewater should not

be overlooked. The wastewater effluent literally becomes too valuable

to discard when the cost of up-grading its quality to meet market re-

quirements becomes competitive with the cost of alternative sources of

Hardness and alkalinity reductions are enhanced only by exten-

sive recycle of sludge and no amount of sludge recycle practically attain-

able appears sufficient to obtain the degree of hardness and alkalinity

reductions experienced with natural x^aters. Excellent reduction of alka-

linity can be obtained by conducting the lime treatment in two stages. In

the first stage, an excess of lime is added and the sludge consisting of

precipitated calcium carbonate, calcium phosphate, and particulate organic

matter is allowed to separate. The clarified water is recarbonated in the

second stage in the presence of recycled calcium carbonate sludge. This

process is being evaluated at Blue Plains.

Lime-treated effluents can be polished by filtration for further

substantial reduction of phosphorus, as well as BOD and suspended solids.

Performance of a sand filter following the DENSATOR unit at Pomona is shown

in Fig. 6. At pH 10.0, effluent phosphorus was down to 0.25 mg/1, an

overall removal of better than 97 per cent.

Additional pilot-plant data from a lengthy investigation at Tucson,

Arizona, are presented in Table 1. Recarbonation ahead of filtration is

most likely indicated for full-scale installations of this type.
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-6-
TABLE 1

Performance of Pilot-scale, Lime-process DENSATOR
and Sand Filter on Activated Sludge Effluent at
Tucson, Arizona

Constituent, mg/1
PH
Total phosphorus, as P
Chemical oxygen demand
Phenolphthalein alkalinity, as CaCC>3
Total alkalinity, as CaC03
Total Hardness, as CaCOs
Turbidity, SJU
Ammonia nitrogen, as NH3
Silica, as Si02

Influent
7.6
10
60
0
250
200
10
25
35
Sand Filter
Effluent
10.5
0.23
50
100
150
100
2
25
25
Split treatment was used in the Tucson DENSATOR. Chemical treat-

ment comprised 310 mg/1 of hydrated lime fed as a paste under conductivit

ratio control plus 20 mg/1 of ferrous sulfate coagulant. A minimum slurr

concentration in the primary reaction zone of four per cent by weight was

achieved by sludge recycle during this study. Sludge blowdown was only

0.13 per cent of the throughput by volume and contained 30 per cent solid:

Cos t Cons id erations

The estimated capital cost of a 10-mgd, single-stage, lime-process

plant for phosphorus removal is $425,000. For debt service at 4.5 per

cent for 25 years, the unit cost of capital amortization is 0.8 cents/1000

gallons of wastewater treated. Further assumptions of chemical use as 300

mg/1 of hydrated lime plus 50 mg/1 of ferrous sulfate coagulant and sludge

disposal by a 25-mile haul to land fill lead to operating and maintenance

costs of 3.5 cents/1000 gallons. The total cost of 4.3 cents/1000 gallons

is viewed as a conservative figure which would reduce to about 3.5 cents/

1000 gallons if sludge disposal and lime recovery by calcination were
-------
-7-

adopted (3) (4). Inasmuch as the lime dose necessary will depend on the

wastewater alkalinity and the degree of phosphorus removal desired, actual

costs will differ somewhat from these hypothetical figures in response to

specific requirements and conditions.

Recarbonation, when required, adds one cent to the above costs.

Two-stage lime treatment on this same scale, including on-site recalcina-

tion, will cost approximately 6.5 cents/1000 gallons, and the estimated

total unit cost for filtration only is 3.5 cents/1000 gallons.

The cost of treatment in this manner beyond that provided by

secondary systems as now designed must of course be added to present costs.

Accordingly, appraisal of current practice in the light of new requirements

such as phosphorus removal is warranted. Through a contract research pro-

gram with FWPCA's Advanced Waste Treatment Group at Cincinnati, INTILCO

has examined the potential for an integrated sequential combination of bio-

logical and chemical treatment (2).

Good biological removal of soluble organics can be realized in

much less time than is presently the case in practice if the requirement

for bioflocculation in activated sludge treatment can be overcome by appro-

priate subsequent chemical treatment. From laboratory and pilot-plant

study of a highly-loaded, short-detention activated sludge process followed

by a solids-contact chemical treatment system it was concluded that the

combination system is capable of exceeding performance of conventionally

designed activated sludge systems and offers important advantages in

treatment stability and flexibility. The greater operating cost of the

two-stage system is offset by lower capital cost and it appears that such

plants can be constructed and operated at the same total cost as that of

the traditional system.
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-8-

Lime flocculation of Tucson sewage at pH 8.9 in the second stage

lowered the Influent total phosphorus concentration of 9.0 down to 0.76

mg/1, a removal of over 90 per cent. Thus, particularly when removal of

phosphorus is a treatment objective, a system of this type has applicatic

to modification or expansion of existing activated sludge installations

and new-plant construction.

Additional INFILCO research reported two years ago in a series of

national seminars entails use of a DENSATOR-filter combination as the firs

component of a complete wastewater renovation system (5). Following re-

duction of suspended solids, phosphorus, hardness and alkalinity in the

pretreatment system, the process continues with adsorption of organic

matter by thermally regenerated activated carbon and demineralization by

multi-bed ion-exchange. The product water from such a system of course

contains no phosphorus and its quality in other respects is excellent. Pro-

duct recovery for the overall system exceeds 90 per cent.

On a 10-mgd scale, the high-quality water will cost about 40 cents/

1000 gallon (the exact figure is strongly influenced by the dissolved-

solids content of the local water supply.) This cost, although high, com-

pares favorably with figures for alternative complete wastewater systems

under study. Where water of intermediate quality is suitable, the concepts

of split treatment, partial demineralization, and blending may be applied

to advantage and can generate significant economy.
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1
]
-9-
References:
1. Stephan, David G. and Leon W. Weinberger, "Wastewater Reuse-Has
It Arrived?", Jour. WPCF, 40:529 (April 1968).
2. Garland, C. F. and G. L. Shell, "Integrated Biological-Chemical
Wastewater Treatment," a report submitted under Contract No.
PH 86-63-220 between FWPCA and INFILCO/GATC (November, 1966).
3. Smith, Robert, "Cost of Removing Phosphorus From Wastewater,"
FWPCA Seminar on Phosphorus Removal, Chicago, Illinois (May 1-2,
1968).
4. Smith, Robert, "A Compilation of Cost Information for Conventional
and Advanced Wastewater Treatment Plants and Processes," FWPCA
Cincinnati Water Research Laboratory (December, 1967).

5. "INFILCO National Seminars," a report published by INFILCO/Fuller
Company, Tucson, Arizona (1966).
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CO
<
r
CO
£
I
Q
(0
Lkl
Q£
12
10
8
P-REMOVAL BY VARIOUS COAGULANTS -
• HYDRATED LIME
A ALUM
o FERRIC SULFATE
100 200 300 400 500
CHEMICAL DOSAGE, mg/1
60O
Figure 1 - Phosphorus removal by various chemicals. Labora-
tory data for treatment of effluent from a heavily
loaded activated sludee system.
"1.
LIME FEED
TREATED
WATER |1
OUTLET

DRAIN
TRAW WATER
INLET
SLUDGE
RECIRCULATION
Figure 2 - The DENSATOR high-density, solids-contact unit.
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or
U)
a:
o
14
.2
lo
8
O
a. e
DENSATOR PERFORMANCE
POMONA, CALIF
AVG INFLUENT PS II mg/l
'9.0 9.5
10.0
pH
10.5
1.0
Figure 3 - The effect of pH on phosphorus removal by DENSATOR
lime treatment of activated-sludge effluent at
Pomona, California (LACSD data).
IL5
ILO
x
CL

ZI0.5
UJ
UJ
O
9.0
pH Vs LIME DOSAGE AT POMONA.CALIF.
I
I
150 200
250 300
Co (OH)2
350 400 450
DOSAGE, mg/l
500 600
Figure 4 - The relationship between lime dosage and pH for
DENSATOR lime treatment of activated-sludge
effluent at Pomona, California (LACSD data).
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-------
'INFLUENT WASTEWATER
FL
LIME

OCCULANT
h-
w
TREATED
WASTEWATER
«" •
WASTE
*
PRIMARY
REACTION
ZONE
\
SECONDARY
REACTION
ZONE
\
SOLIDS
SEPARATION
ZONE
I
DENSE SOLIDS
SLUDGE
<-
mm
SOLIDS RECYCLE
Figure 5 - Flow diagram for split treatment in the DENSATOR
high-density, solids-contact unit.
'HOSPHORU!
"-a.
1-
^

LJ
tr
LUU
0.75
0.50
0.25

1 1
SAND FILTER
PERFORMANCE
POMONA, CALIF. "
\ .
\. *
•*** — -_ •
*•
i i

10.0 10.5 11.0
PH
Figure 6 - Residual phosphorus versus pH for lime-treated
and filtered activated sludge effluent at
-i -Fm-nT :
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-------
INFILCO DENSATOR TREATING PLANT
Steel Tank
360* PERIPHERAL
LAUNDER
SLUDGE
RECYCLE
E EFFLUENT
PLAN
[—
1 _J
1 f
.A,,
J

^ i
i
j
V
PERIPHERAL
LAUNDER
SLUDGE
RECYCLE ~
s
tt *
SECONDARY
WATER
FLOW
COCKS
• EFFLUENT
--UANHOCE
CAPACITY 6PM
A
B
C
D
E
F
6
H

MSIDE DIAMETER
DEPTH
DRIVE (HP)
INFLUENT

EFFLUENT
OVERFLOW
SLUDOE BLOW-OFF AND
"WIDE » 'DEEP

SECTIONAL ELEVATION
R COMPAIMY / GENERAL AMERICAN TRANSPORTATION CORPORATION

INFIUCO PRODUCTS

P.O. BOX SO33. TUCSON. ARIZONA B57O3. TELEPHONE SOa/S23-5
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-------
INFILCO DENSATOR TREATING PLANT
Steel Side Sheet with

Concrete Bottom
SCO* PERIPHERAL
LAUNDER
PLAN
SPUTTER
/BOX ^—
INLET
PRIMARY
C'
DRIVE
"H-
PERIPHERAL
LAUNDER ~-
3LUDSE
RECYCLE
SECOSDARY
INLET
CAPACITY GPM
A INSIDE DIAMETER
B IDEPTH
C
D
E
DRIVE (HP)
INFLUENT
EFFLUENT
f , OVERFLOW
6 . SLUDGE BLOW-OFF ANO
H

PRIMARY
REACTION
ZONE
SECONDARY
~ CTiON
(4) BAFTLESS9O*
(EACH ZONE)
^CONCRETE BOTTOM
WITH STEEL TANK
SIOESHEET
SECTIONAL ELEVATION
GATX
FULLER COMPANY / GENERAL AMERICAN TRANSPORTATION CORPORATION

INFILCO PRODUCTS
-------
-------
IHFILCO DENSATOR TREATING PLANT
3«O* PERIPHERAL
LAUNDER
LIME
LINE
SLUDGE _____,,
RECIRCULATJOtT^
Steel Side Sheet with
Sloping Concrete Bottom
PLAN
SPLITTER
BOX ADJ C" ROTOR "j" SCRAPER
I ^VKEIR DRIVE DRIVE
CAPACITY 0PM
.
i MOTOR
JNFLUENT
Pi
__________
L8LUOOE BLOW-OFF _ANO OR AIN
* WIDE ' "DEEP LAUNDER
' I SCRAPER DRIVE (HP)
SECTIONAL ELEVATION
CONCRETE BOTTOM
WITH STEEL TANK
SIDESHEET
FULLER COMPANY / GENERAL AMERICAN TRANSPORTATION CORPORATION

INFILCO PRODUCTS

_ „. ,„ —. A—TT-IMA B57O3.TELEPHONE SOa/6a3-5
-------
-------
ad Control of
S . ™ -^=» 5
1.^. - : ^PAr^Y/OENERAL AMERICAN
-------
-------
\
-------
Improved filter plant performance
Lower installed cost
Minimum space requirements
Reduced maintenance costs
Flexibility of filter plant design
The Greenleaf Filter Control offers a new design concept for controlling the functions
of multiple rapid sand gravity filters, utilizing conventional low head loss underdrain
systems, filter media, and filtration rates. It is not a new filter design. The filter design
is by the consulting engineer or industrial water treatment specialist—incorporating his
own and regulatory agency standards. By incorporating the Greenleaf Filter Control
Center in the design of filter plants, the consulting engineer can offer a superior and
highly economical method of control in his filter installation.
-------
-------
a "-.
A
*=™ "3* I (I -«•
/• S 6*3 i
TV
~
iproved Filter Plant Performance

:ers are always under positive head
s impossible to apply a negative head or draw air into
5 filter bed because the filtered water discharges over
adjustable effluent weir above the elevation of the
:er media.

possible to shock or surge a filter
e Greenleaf Filter Control provides an idea! filter cycle,
ice all rate of flow increases and decreases are gradual.
is impossible to upset the filter bed by sudden in-
eases in backwash flow or by pulsating flows due to
alfunction of controllers during operation.

)w i^Mually and automatically divided among the
ters^pperation

D mechanical flow controllers are required—flow control
nong the filters is achieved by basic hydraulics. Rec-
ngular weirs with free fall at each filter cell equally
vide the inflow. When one filter cell is being back-
ashed, its inlet siphon valve is stopped and total flow
equally and simultaneously divided to the operating
ter cells.

mplicity of operation

II filter control functions are located in a control center
^ound which the filter cells are placed. The operator
an easily select and control any individual filter cell from
.e common control location. All controls are visible
Dove the filters. Accessibility, convenience of a corn-
on location, and choice of local or remote operation are
rovided—any degree of automation can be included.
entralized control means simple, economical operation.

ackwash water can be provided by the filtering cells

ilters and control centers are designed to provide the
Iter rates specified. Multiple filter control units (two or
lore filter control centers) allow one filter cell to be
ack'^fched from filtered effluent of the other filter
ells^mhout drawing on clearwell capacity.

iiphon valves contribute to efficient operation

"he siphon valves control the filtering and backwashing
:ycles and are extremely simple in operation. These
.*>*& ,^tx "^ "j '
\s& -•».
valves are connected to a vacuum system by small indi-
vidual 3-way actuating valves to initiate and stop the flow
of water during filtering and backwashing.

Reduces Both Initial and
Installation Costs

Careful evaluation of all major equipment and installa-
tion costs indicate a savings of approximately 20% in
the cost of a 5 mgd filter plant. In larger plants, greater
savings can be expected.

The Greenleaf Filter Control eliminates

Filter pipe galleries • interconnecting filter piping •
line-size filter operating valves • filter effluent control-
lers and control systems • filter gauges • backwash
controllers and gauges • pneumatic control systems.

Pre-fabrication reduces field installation costs,
insures design accuracy

The ease and economy of installing the Greenleaf Filter
Control significantly reduce field construction costs. The
central control center is pre-fabricated and shipped in a
minimum number of sub-assemblies. Pre-fabrication of
the control center assures design accuracy.

The central control compartment which includes the
backwash siphon valves, inlet weir chamber controls and
inlet feed channels is in one pre-assembled unit. (The
D-4 unit is shipped in quadrants.)

The control compartment is placed on a flat concrete
slab and grouted in place. The annular feed channel and
inlet siphon valves are then assembled onto the control
compartment.
Excavation problems minimized in clearwell
construction

Because of the positive head design of the Greenleaf
Filter Control, no deep excavations for the clearwell are
required since the clearwell need not be located under
the filters as in conventional designs. This results in a
great savings under conditions of improper soil or rock
foundation. Additionally, the clearwell site can be selec-
ted for optimum land usage.
I
L
L
ill
r
i
IV
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-------
imposing any design restrictions on the individual filter plant, the Greenleaf Filter Control
sffers a functionally perfect and simply operated control of the filter plant. It has substantial cost,
space and maintenance advantages.
.ower Maintenance Costs
"he Greenleaf Filter Control assures reduced mainten-
ince costs:

'isible controls

Ml controls are visible above the filters and readily ac-
;essible for maintenance and servicing.

Design simplicity

Simplicity of design and minimum use of equipment with
moving parts substantially reduce maintenance
•equirements.

(/linimized components

Elimination of large valves, extensive piping runs, pneu-
matic flow controls and instrumentation significantly
'educajnaintenance costs.
u^yri
:lexibility of Filter Plant Design
The Greenleaf Filter Control allows designs for flows of
less than 1 mgd up to large multi-mgd systems. A single
'ilter control center can be used for capacities up to
approximately 9 mgd; multiple control centers are used
'or higher flows. Filter construction may be round, square
or rectangular depending on design criteria.
Minimum Space Requirements
We have computed by actual comparison a space saving
of approximately one-third of that required for a like-
capacity plant utilizing conventional filter control sys-
tems. The arrangement of the filter bays around the
control center eliminates most of the connecting and
control equipment of conventional filter controls, and
provides an extremely compact filter plant. Additional
space saving is realized by the use of siphon valves for
the filtering and back-washing cycles to replace the con-
ventional line-size water valves. The drawing below dem-
onstrates the relative space requirements of like capa-
city filter plants using the Greenleaf Filter Control and
conventional controls.
FILTER PLANT V.ITH GREENLEAF FILTER CC\" J_S
J
FILTER PLANT WITH CONVENTIONAL CONTROLS
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-------
LJOO joj pasn a9pa Sui||ids e S| JJSM v '9
iioAjasajja;eMpaj3;jij am s| HaMjeap -g
•uoqdis aq; qSnojq}
M3|j aq; do;s o; pa;uaA aq Jo uoqdis
tit; qSnojq; M°|j B ;JB;S uea qoiqw
iDjnos tunnoBA e o; do; aq; ;e uoipau
-uo3 B q;|M uoqdis e si BAIBA uoqdjs v
•adid ^uani^a am uo
|eas ja;BM am O} uiejpjspun aq; LUOJ;
jajew jo mdap am si Lus^sX
J31PJ |euoi)uaAuo3 e ui peaq
•apAo ijSBM^oeq ui
qseM sm aAoqe
aq; ui ja;eM p mdap am pue
uo|;ej;n; am ui uoi;eA3|3 JJBM
aqj aAoqs uiseq ja;i^ aq; u;
aq; si
;o'a3BSSBd o; paq
aqi jo a3ue;sis3J aq; si peaq ;o sso-| '\

SIA1U31 JO AdVSSOTO
fV,-.^.-, .....„.- ,.-**^
y* Jj.':'~^^.'.ja.-«^ if+^j.: .
f^ j a33.WhD!j3i*W
JDJ pest] 3|qB|iEAe Luniuixeuj aq; si ||90
|3A9| J3J6M qSlL) 31]^ 0^ JI9M |OJ}UOO lU9n|^S 3L|
3isu3LUip aq_L "a^BJ qseM aq; gjopjaq; pue peaq a|qe
BAB aq; aSueqo ueo jia«\ JOJ;UOD ;uan|j.;a aq; p uoi;eA3|a
^ p ;uaoi;snfpv 'pasn si uiejpjapun ;o adA; sso| peaq
0| e ^i a;ej qseM •;; •bs/md§ gi e apjAOJd HIM jiaM |oj;
oo ;uan|^a aq; o; q§noj; qseM aq; jo do; aq; UJQJ^ ,,Q-/£
A|a;eujixojddv 'pa-inseam si
q;oq jo; peaq a|qe|ieAe
|oj;uoa
pue §uua;|i;
LUOJ; ;uiod oin;ep aq; si
aq; ;o uoi;eA3|a aqj_
•pajmbaj se papnpui aq ABOJ
sajn;ea; jepads jaq;o pue suoi;eoo| uie^iao ;e uoi;onj;s
-uoo IJSM aiqnop 'suo!;e||e;sui ja;eM 9|qe;od u[ 'uoi;
-ejado p suoipun; aq; a;ej;snni s|oj;uoo ^eaiuaajg pue
S||ao ja;m jo sSuiMejp jeuoipas-ssojo §UIMO||OJ. aq; p nv
-------
-------
Greenleaf filter control installation at paper processing plant
-------
-------
f"-,. •

\i
#
J
; '
v<
-------
-------
j~'i., A si JJ i
^.'\i r* T" i6T
I xf U
Schematic Filter Cycle

"he diagram illustrates the facts that the filter is always
jnder positive head and that all filter functions are
:ompleted in a hydraulically perfect cycle. This sche-
natic drawing does not in any way reflect the relative
ime periods of the filtration and backwash cycles. The
:ero point on the curve represents the elevation of the
jffluent control weir. During the filtering cycle, the head
>n the filter increases above this elevation as the filter
jnit becomes dirty. After the inlet siphon valve has been
lopped, the head or level decreases until hydrostatic
is achieved. The operation of the backwash
allows the positive head at the effluent
weir to initiate backwashing. As the level in the filter
lowers towards the wash troughs, the increasing head
builds the wash rate to maximum design which is main-
tained until the backwash siphon valve is vented. The
rate of flow then decreases gradually and allows the bed
to settle until the zero point is reached. The inlet siphon
valve is then started and the filtering cycle begins anew.
All rate increases and decreases are in proportion to
the square root of H. A perfect cycle is thereby achieved
without the use of rate of flow controls. The operator
cannot shock or surge a filter.
- 4
z
D 3
<
> 2

y5
i
NORMAL FILTRATION
INLET SIPHON
I VALVE
I OFF
CONTINUOUS FILTRATION
CONSTANT BACKVV
iVASH
BACKV.ASH SIPHON
VALVE
OFF
CONTINUOUS BACKWASH
INLET SIPHON
VALVE ON
BACKWASH SIPHON
VALVE ON
INLET SIPHON
VALVE ON
-------
-------
r r - - \ =• /
•
0 VACUUM PUMP
A) AN\jL*R DIST^tBUTCR CHANNEL
EFFLUENT

CONTROL WEIR
-•! /" : "
•^=^f
>^f^^^^. • _.

'; " ~-._~~" v
- ™— «!JB«- "' r~~ ^— ^

^-^^—NJ
VACJUM TANK
F J EFFLUENT WEIR CHAMBER
EFFLUENT

CONTROL WEIR
FILTERED V.ATER TO

STORAGE OR SERVICE
BACKLASH V,ASTF SECTION
10
-------
-------
VACUUM TANK
ELEVATiON OF FILTERED
AATER OVERFLOW
VACUUM TANK
-------
-------
L
12
f.O 3 WAY VALVE (ACTUATES BACK/.ASH SIPHON VALVE)
J J BACKWASH SIPHON VALVE
FILTERED WATER TO
STORAGE OR SERVICE
BACKWASH ^ASTE SECTION
-------
-------

]
BACKLASH SIPHON VALVE
ELEVATION OF FILTERED
V.ATER OVERFLOW
FILTERED WATER TO
S'C^AGE OF SERVICE
VACUUM TANK
3 V.AV VALVE (ACTLMTES INLET S'PHON VALVE)

3 V.AV VALVE lAC'tATES BACKV-ASH SIPHON VALVE)

SIPHO% VALVE
- il
EFFLUENT
CONTROL WEIR
FILTERED WATER TO

STORAGE OP SERVICE
BACKWASH rtASTE SECTION
-------
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Underdrain Systems
Filters designed to utilize the Greenleaf Filter Control
should incorporate underdrain systems which operate
efficiently with low loss of head during backwash. The
Infilco Fre-Flo underdrain (shown below) is recom-
mended in that it fulfills the requirements for low head
loss and excellent distribution of backwash water. This
underdrain has a life expectancy equal to the rest of the
filter plant. The trapezoidal beam type underdrain is
also recommended as it reduces installation cost since
beams can be cast at the job site during the pouring
of concrete for the filter walls.
Vacuum Tank

Vacuum is used to actuate the siphon valves. The vol
of air to be removed is so small that constant vac
is maintained in the tank by minimal operation of
vacuum pump. A single tank with a double compartr
and drop legs provides the two different vacuurr
quirements for the inlet and backwash siphon va
(approximately 2.0 inches and 15.0 inches of mer
respectively) from a single vacuum source. The vac
pump is connected to the high vacuum compartr
and is controlled by an electrode-type level switc
this compartment. The low vacuum compartment is
plied from a differential drop leg assembly. The sho
low vacuum drop leg is located within the high vac
drop leg. The high vacuum leg is open at the bot'
but it is sealed by the minimum water level mainta
by the drain outlet in the control center. The he
of the open bottom of the low vacuum leg above
drain elevation is equal to the low vacuum requirerr
When an inlet siphon valve is actuated, the air in
inlet siphon is vented to the low vacuum compartrr
This air travels to the point of lowest pressure whit
the bottom of the low vacuum drop leg, bubbling thrc
the water in the high vacuum drop leg to the
vacuum compartment of the tank. The air enters
high vacuum compartment and causes the water
to recede, operating the electrode level switch and s
ing the vacuum pump to restore the water level t
normal position of approximately 17 feet above
drain. All points are considered in terms of abs<
pressure.
TO VACUUM PUMP
TO INLET SIPHON VALVES
ABSOLUTE
PRESSURE
(FT.)
14
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Dperating Controls
Operating controls are available in remote manual, semi-
lutomatic or fully automatic designs housed in free stand-
ng modular cabinets. With minor electrical changes,
ny system can be converted to either of the others, or
'xpanded to accommodate additional filter control units.
n the event of power failure, filter cells in service will
•emain in service and a cell in backwash cycle will return
o service. When power is restored, the interrupted back-
vash cycle will be re-initiated.
"he modular cabinets are shipped completely equipped,
issembled, wired, piped and pre-tested in the factory.
Siphon Valves
The siphon valves of the Greenleaf Filter Control are
ON-OFF valves and are not flow control valves. Siphon
valves are actuated by the 3-way actuating vales at the
vacuum tank.

For the filtration cycle, the siphon valves start or stop
the flow between the annular inlet flume and the indi-
vidual compartment of each filter cell. For the back-
wash cycle, the siphon valves start, maintain or stop the
flow between the filter cell forebays and the backwash
waste section in the central core. Siphon valves, which
have very small head loss, are economical and easy
to operate.
TT T7 IT! T7 T7

! \ •'"•- \m •' •* \ \ '•»
\ ' ' r- \ > r-
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-------
There shall be furnished and installed Greenieaf Filter Control unit(s) having a total capacity
gallons per minute when filters are operating at the rate of gallons per mintue per squa
foot. Maximum backwash rate for one filter cell shall be gpm.

The Greenieaf Filter Control unit(s) shall be designed to permit a maximum filter head loss of fe<
The head required for backwashing a filter shall be feet. The Greenieaf Filter Control unit(s) sh
be as manufactured by Fuller Company, Tucson, Arizona.
Control Units
Each control unit shall consist of one annual feed ch<
nel and individual weir chambers for each of the fill
cells. The water to be filtered shall be introduced to t
annual feed channel through an inlet flume. Inlet siph
valves shall connect the flow of water from annular fe
channel to the weir chambers which regulate the fl<
of water over free fall weirs to each filter cell. The bat
wash siphon valves shall be so arranged as to take wa1
from each filter cell and deliver it to a central co
partment from which it shall flow to waste over
internal outlet weir.

The central control compartment, including backwa
siphon valves, feed conduit and weir plates shall be
welded construction and shall be fabricated of AISI Ty
304 stainless steel. The annular feed channel and in
siphon valves shall be welded mild steel. The cont
section shall be fabricated in section(s) to
assembled at the project site. The inlet flume shall
of concrete/steel and shall be furnished by the cc
tractor/equipment supplier. A %" checker-plate st<
walk-way and V/2" pipe handrail shall be provided 1
access to the filter control unit.

Outlet Weir
An external adjustable outlet weir for manual cont
of the hydraulic head shall be provided by the equ
ment manufacturer. The weir shall be installed in t
external weir chamber by others.
16
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facuum System
, vacuum system for each control center shall be fur-
ished and installed. It shall consist of a two compart-
lent vacuum tank, drop legs, piping connections and
-way valves connected to the siphon valves, and a sight
;lass. The 3-way valves shall actuate the siphon valves
t the direction of the operator. Piping shall be of the
ize |^^/n and shall be installed as indicated on the
rawr
facuum Pumps
.... electric motor driven, single stage, water sealed,
otary type vacuum pumps shall be furnished and in-
tailed as shown on the drawings. Each vacuum pump
hall be an approved electric motor-driven type, having
capacity of .of air at a vacuum of 15 inches hg.
n multiple control center installations, the vacuum
lumps shall be manifold to the various vacuum tanks
3 serve all control centers.

/lotors shall be ... .horsepower, drip-proof/T.E. in-
uction motor suitable for operation on . . . .phase, ....
ycle, . . .volt alternating current. There shall be fur-
ished and installed in the vacuum system an electrode
ssembly to control the operation of the vacuum pumps.
:ilter Underdrain System
"he filter underdrain system shall be as specified else-
where. Pressure access hatches to the false filter bot-
om.j^jequired, shall be furnished by others.
Wash Troughs

Filter wash troughs shall be installed in each filter cell
so that they are Igvel throughout and rigidly supported
for both internal and external loads. They shall be sup-
plied as indicated on the drawings.

Operating Console
There shall also be furnished and installed on the operat-
ing floor, as shown on the plans, an Infilco Operating
Console which shall provide remote manual/semi-auto-
matic/automatic control. There shall also be installed
in the Console, similar remote controls for operating the
surface wash system and valves in each filter cell, if
necessary. The details and arrangements of the Console
shall be approved by the engineer before fabrication.

Surface Wash (optional)
Surface wash units shall be installed as shown on the
drawings and in accordance with the recommendations
of the manufacturer of the equipment. There shall be
installed in the water supply line to each surface wash
unit, a type valve which will be remotely operated
by from control valves installed in pipe to
washers and their support will be by others.

Filter Isolating Valves (optional)
Filter isolating valves (sluice gates) shall be provided
for each control center (filter cell) to isolate the filter
units (filter cells) and take them out of service for in-
spection, maintenance and repair.
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INSTALLATION

Nekoosa-Edwards
Paper Company
Kimberly Clark
Corporation
County Water
Chrysler Corporation
Commonwealth Edison Company

City Water
Crown Zellerbach Corporation
City Water
City Water
City Water
City Water
City Water
City Water
City Water
City Water
City Water

E. I. DuPont De Nemours
and Company

Bergstrom Paper Company

City Water
City Water
City Water
Cable Company, Ltd.
Fertiberia, S.A.
Ensidesa Steel, S.A.
City Water

City Water
LOCATION

Arkansas
Ashdown
Connecticut
New Milford
Florida
Ft. Meyers
(Lee County)

Illinois
Belvidere
Kincaid

Indiana
South Bend

Louisiana
St. Francisville
Houma

Minnesota
Mankato
Norwood
White Bear Lake

North Dakota
Ashley
Dickinson
Drayton
Grand Forks

South Dakota
Springfield

Texas
Beaumont
Wisconsin
Neenah

Canada
Terrebonne, P.Q.

Japan
Koriyama
Iruma City
Hitachi

Spain
Huelva
Aviles

Hong Kong
Taipo

Viet Nam
Bien Hoa
TOTAL CAPACITY I

3,500
1,500
1,200

8,400
14,000
5,600
6,300
400
5,000
400
3,000
500
4,200

4,400
4,200
3,500

3,000
18
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-------
City Water Plant
South Bend, Indiana
Crown Zellerbach Plant ?
St. Francisville. Louisiana
City Water Plant
White Bear Lake,
Minnesota
-------
FULLER
ENGINEERED PRODUCTS FOR INDUSTRY...
AIR HAIMDLIIMG EQUIPMENT . . . Fuller rotary compressors, Sutorbilt blowers and
Lehigh1 fans
PNEUMATIC MATERIALS CONVEYING SYSTEMS . . . Airveyor^, Airslide* and
Fuller-Kinyon conveying s'ystems
POLLUTION CONTROL EQUIPMENT . . . Dracco1 dust collectors, Infilco water and
sewage treatment systems
HEAVY PROCESSING MACHINERY AND SYSTEMS . . . Traylor crushers, kilns
and mills, Fuller grate coolers, fluid bed reactors and Fuller specialized equipment for
the mineral industries
GATX
Offices in principal cities of the United States and Canada
INFILCO

O. BOX SO33, TUCSON. ARIZONA BS7O3

PRINTED IN U.S.A. N-310 5M-6-
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-------
A
ULii n.! -i •
VH-'*™-- -~.- -^ - — w.
-«.
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V^JIA* tl
>-"~L .,,
: Mir
The "AERO-ACCELA TOR" activated sludgt
plant is proven equipment based upon establishei
principles of hydraulics and bio-chemistry. It is de
signed for the treatment of both domestic sewage am
industrial wastes. The unit provides a compact, highl]
efficient plant, with conventional design factors estab
lished by the Consulting Engineer.
The "AERO-ACCELA TOR"plant is designer
for activated sludge treatment, and incorporates th(
established advantages of complete mixing. In addi
tionf the "AERO-ACCELA TOR"design inhe,
ently has plus factors not obtainable in other design'
Consistently, it provides 90% or better BOD remove
with rapid and continuous biological oxidation. Ther
is efficient solids separation under positive aerobi
conditions.
The "AERO-A CCELA TOR"plant is of prove
design using established loading factors and a highl
efficient mechanical air disperser. As a result, it wi
handle biological loadings in less space than convet
tional plants. There is consistency of performance an
economy in first cost and operating cost.
©• FULLER COMPANY 1957. 1961 & 19(
-------
-------
The "AERO-ACCELATOR" activated sludge unit is a proven
design. There are more than two hundred and seventy-five
successful installations treating domestic sewage and
industrial wastes. Consulting Engineers have determined by
their experiences with the design and operation of "AERO-
ACCELATOR" units, that the consistency of good treatment
and its compact economy provide a unit to be specified on
many projects.
Experience in the treatment of domestic sewage, phenolic
wastes, packing house wastes, paper mill wastes, and others,
has been obtained. The largest completely mixed activated
sludge plants in the world were both supplied by INFILCO.
The circular 175' diameter "AERO-ACCELATOR" unit at
Whippany Paper Board Company, Whippany, New Jersey,
with a previously supplied 110' diameter unit, handles a total
flow of 11 MGD with a BOD of over 400 mg/l from three
company mills.
Eight recfangu/ar "AERO-ACCELATOR" units at the Shi-
baura plant in Tokyo are currently treating more than 17
MGD of domestic sewage.
INDEX

Acceptance Page 22-23
Applications Page 14-15
Design -Page 6-7
Dimensions, Standard Page 18-21
Economy Page 12-13
Experience Page 3
Flow Sheets, Standard ....Page 7
Installations Page 16-17
Modifications Page 14-15
Operation Page 8-9
Performance Page 10-11
Plant Layout Page 24
References Page 25
Specifications, Standard Page 26-27
Theory Page 4-5
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-------
In
n I
Cii
O O © Until recently, the design of the activated sludge process has
included a great deal of empiricism. Fundamental study of the process has
brought about its more efficient and economical use. INFILCO,through its
research and development, has pioneered the practical application of the
completely-mixed concept and has confirmed biological design factors
established by many investigators.*
Activated sludge treatment is a biological process in which bacteria and
other types of minute living organisms do the work. If these micro-organisms
are to function at maximum efficiency, they should be in a state of constant
and uniform growth. The essential conditions of such growth are:

• O G A continuous supply of waste having a uniform and nutrition-
ally adequate organic content.
Complete mixing of raw waste and microbial population.
C An uninterrupted supply of dissolved oxygen.
Efficient separation of treated waste and biological floe sc
as to retain the latter and discharge the former in a quantity
equivalent to the raw waste feed volume.
The traditional system is a cyclic one wherein waste is agitated and aerated in the
presence of biologically active floe in an aeration basin. The effluent is subsequently
separated by sedimentation, and the floe, or activated sludge, is returned to th«
process or wasted as required. However, various investigators* have establishec
that there are disadvantages in employing the traditional process with this cyclit
system vvherein the organisms are over-fed at one stage and then are allowed tc
become starved and depleted of oxygen before they are reused in the process.

These inherent weaknesses in the traditional activated sludge process have turnec
the attention of engineers to the development of a homogeneous process.

The completely-mixed system, embodied in the "AERO-ACCELATOR" design
provides ideal conditions since the organisms are kept in a constant and uniforn
state of growth. Incoming wastes are completely mixed with the entire content
of the aeration tank. The aeration tank acts as an equalizer of the biological loa<
and the activated sludge is not subjected to shock loadings. Some of the organism
which are dying are continually releasing nutrient materials, and in such a homo
geneously mixed system, this release and demand for nutrients occur at the sami
point.
* Note References.
-------
-------
It can be generalized that the efficiency of biochemical treatment, as measured by
,-> x-v * ir-v |-|-i/^i N iQ BOD removal, is related directly to the weight of biologically active solids in the
^v-'INL'l I IvylNO system and inversely to the applied BOD. It follows that neither the waste concen-
tration nor the mixed-liquor aeration period are of fundamental significance. When
successful operation at high MLSS (mixed-liquor suspended solids) concentrations
is possible, considerably smaller aeration basins can be used than have been utilized
in the past. Economic and technical limitations in this regard include the oxygenation
capacity of the aeration system, the influence of MLSS concentration on the effec-
tiveness of liquid-solids separation, and the return-sludge capacity required for
operation at high MLSS levels.

The oxygen absorption efficiency of conventional diffused-air systems ranges up
to 10% and most of the air supplied is required to keep the sludge in suspension.
Experience has demonstrated that the VORTI-MIX® turbine aerator (or VORTAIR®
surface entrainment aerator) component of the "AERO-ACCELATOR" unit will
properly mix and oxygenate higher MLSS than can be effectively separated in
conventional practice.

The circulation between the aeration and clarification zones can be controlled. In
most applications, it is four to five times the throughput

This is several times the return-sludge capacity provided in the traditional system,
and eliminates this particular restriction on MLSS concentrations.

Liquid-solids separation in the traditional activated sludge process is accomplished
by transferring mixed-liquor solids from the aeration basin to a gravity-type settling
and clarification unit. Due to the time required for settling and thickening, the
biological solids are kept away from any dissolved oxygen for as much as an
hour or more. This is undesirable since aerobic organisms cannot maintain their
vitality for any length of time in the absence of dissolved oxygen.

In the "AERO-ACCELATOR" design, there is no possibility of sludge septicity
caused by settling outside the zone of active aeration In the "AERO-ACCELATOR"
unit, biochemical oxidation and clarification take place in a single multi-purpose
structure. The activated sludge is constantly being recirculated, under aerobic con-
ditions, from the solids separation zone into the aeration zone.
• Clearly, the AERO-ACCELATOR plant provides a biological environ-
ment which meets the requfremenfs outlined for an efficent treatment system.
-------
-------
\\ 11
DESIGN
BASIC FACTORS
A wide range of loading possibilities is available for a specific design of
simple and rugged process as applied in the "AERO-ACCELATOR" i
The engineer may design an extended aeration system from which little
no sludge is wasted; he may elect to design for operation at a higher BC
MLSS ratio with consequent excess sludge production. The choice is influe
ed by local requirements and conditions.

As stated by one investigator* "The desired effluent quality determines the size
the complete mixing system. It is possible to produce an effluent of any desi
organic level from wastes of any organic strength."

The basic design factors that establish the size and volume of an "AEf
ACCELATOR" unit are the aeration volume, total mixed-liquor volume neces<
for handling the biological load, and the clarification area necessary for so
separation.
LOADINGS
CLARIFICATION
Data obtained under controlled conditions indicate that for the cornpletely-mi
system as applied in the "AERO-ACCELATOR" unit, BOD/MLSS loading n
considerably greater than in the traditional activated sludge process are enti
practicable for the same degree of treatment. However, for domestic sew.
, treatment at an average loading of 0.5 pound of BOD per day per pound of Ai
is recommended. Basic unit dimensions on pages 18 to 21 provide for conserve
and conventional loadings incorporating an appreciable safety factor for the sti
normal conditions. Higher concentrations of MLSS can usually be maintained,
sizing of the "AERO-ACCELATOR" unit incorporates adequate high-efficie
oxygenation to sustain any economical loading condition. For stronger wa;
loading ratios in the range 0.5 to 1.0 and higher are often practicable.

The clarification area is established on the basis of the settling characteristics of
mixed liquor. For ordinary activated sludge developed from domestic sewag
maximum overflow rate of 1500 g.p.d. per sq. ft. is used.
AIR REQUIREMENTS
Air requirements are determined from the BOD loading, the oxygen required
pound of BOD removed, and the oxygen transfer efficiency of the aeration syst
The oxygenation device in the "AERO-ACCELATOR" unit is a non-clogging
bine aerator which either disperses compressed air or entrains atmospheric
Oxygen absorption efficiencies of 15 to 25% are economical. The "VORTI-MI
aerator provides about 2.5 pounds of oxygen per hour per horsepower appl
including power for air compression. The "VORTAIR" aerator will provide u|
about 5.0 pounds of oxygen per hour per horsepower applied to the rotor.
* Note Reference 8
-------
c
-------
STANDARD FLOW SHEETS
The "AERO-ACCELATOR" unit offers you -

Savings up to 50% in space requirements.

Mixing, oxygenation and clarification in a single unit.

Round, square or rectangular designs.
"Extended Aeration" if required.

Most efficient biological oxidation in the most
compact plant.
FLOW MEASUREMENT
DEVICE
THICKENED SLUDGE
TO DIGESTER OR OTHER
SYSTEM
INFLUENT
FLOW
METER
ALTERNATE FLOW
MEASUREMENT
DEVICE
COMMINUTOR
SCREEN CHAMBER
EFFLUENT
"AERO-ACCELATOR"
WASTE MIXED-LIQUOR
7. FLOW DIAGRAM FOR NORMAL DOMESTIC SEWAGE.
FLOW MEASUREMENT
DEVICE
INFLUENT
COMMINUTOR AND/OR
SCREEN CHAMBER
THICKENER
OVERFLOW
FLOW
METER
ALTERNATE FLOW
j MEASUREMENT
DEVICE
EFFLUENT
SLUOGEy
^'"AERO-ACCELATOR"
THICKENED SLUDGE
TO DIGESTER,
* LAGOON OR OTHER
SYSTEM.
SLUDGE THICKENER

2. FLOW DIAGRAM FOR WASTE WATERS NOT REQUIRING PRESETTLING.
FLOW MEASUREMENT
DEVICE
INFLUENT
COMMINUTOR AND/OR
SCREEN CHAMBER
EFFLUENT

'AERO-ACCELATOR"
TYPE l-O
MIXED-LIQUOR TO SLUDGE
STORAGE,DRYING BED OR
TANK TRUCK
3. FLOW DIAGRAM FOR APPLICATION OF TYPE l-O, FOR EXTENDED AERATION.
-------
-------
The"AERO-ACCELATOR" Treating Plant with its controlled mixed liquor circula-
tion provides the smallest completely mixed activated sludge plant available for
the effective treatment of municipal and industrial wastes.
The"AERO-ACCELATOR" unit is designed for the treatment of domestic sewage.
The "AERO-ACCELATOR" plant is also designed for the treatment of paper mill,
refinery, and other complex chemical wastes.
The following diagrams and explanations will d«
scribe the flow and functions of the "AERC
ACCELATOR" plant design:
Waste enters the "AERO-ACCELATOR" -
The waste flows through the intake pipe (
at the bottom center below the hood (2) in
the aeration and mixing zone (3).
n
Figure 4
At this point,air is introduced through a span
ring (4) and is dispersed by the"VORTI-AAI
Aerator (5).

The "VORTI-AAIX" Aerator also acts as a rad
type pump which completes mixing of the
and waste and circulates the mixtures witf
the aeration zone (6).
Figure 5
T
Figure 6
The large bubbles of incoming air are brok
into very fine bubbles by the shearing-acti
of the rotor. These fine bubbles promote ra|
oxygenation and provide a lifting action
which conveys the mixed liquor up the ini
draft tube where the flow discharges throu
variable opening gates (8).
-------
T
-------
The mixed liquor then moves down the an-
nular space between draft tubes (9) to the
clarification zone (10). A throughput volume
of clarified effluent is displaced from the mixed
liquor by the newly entering waste. The efflu-
ent rises and flows over the discharge weir
(1 1) at the surface.
Figure 7
The activated solids separated from the in-
fluent are carried back into the mixing zone
beneath the hood by the recirculating volume
of mixed liquor (12). The recirculating flow is
normally four or five times the throughput and
is controlled by varying the area of the gate
openings (8) Solids concentration is controlled
by a timer-activated blowdown (13) or an air-
to an external thickener.
Type 1-0
rrz
13
Figure 8
When designing for high-strength industrial wastes, where the mixed-liquor volume
required is relatively large in comparison with the clarification area needed, the "AERO-
ACCELATOR" unit TYPE I-O is used. In this unit, described in the section - "Modifi-
cations" page 14, the positions of the aeration and clarification zones are reversed.
The"AERO-ACCELATOR"activated sludge plant
TYPE I-O was designed for the treatment of
wastes of high BOD content. Many industrial
wastes, which often have BOD contents of more
than 600 mg/'l require more aeration of a greater
volume of mixed liquor than that required for
domestic wastes The design of the TYPE I-O
unit provides this additional volume within the
aeration zone by placing the larger aeration zone
at the periphery of the basin and the smaller
clarification zone within it. The operation of the
I-O is similar to that of the Standard unit,
ore, the same identifying numerals apply.
Figure 9
-------
-------
<
1JO-
Analytical data from a variety of full-scale installations and pilot plant studies
are available. The treatment of several different types of wastes is illustrated.

DOMESTIC SEWAGE - AVERAGE HOUSING
Run
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
BOD
Influent
(mg/l)
151
127
168
157
134
149
141
111
125
171
219
158
158
126
156
147
125
87
94
96
99
Effluent
(mg/l)
15
6
7
7
7
6
6
5
10
16
14
9
10
10
8
3
5
2
3
3
5
Removal
(%)
90.0
94.5
956
95.4
94.7
95.7
956
958
908
91.0
937
936
93.6
91.8
94.8
97.7
96.3
967
972
970
95.0
SUSPENDED SOLIDS
Influent
(mg/l)
147
147
141
125
120
166
81
74
89
176
181
121
126
92
104
160
119
79
85
87
80
Effluent
(mg/l)
16
22
15
13
16
16
8
5
13
21
13
8
9
11
7
10
10
5
4
6
6
Removal
(%)
889
865
897
896
87.3
90 3
90 1
932
85.0
880
928
870
91 0
85.0
93.3
93.2
91.7
93 7
96.0
928
92.5
The flow rate to the plant varied from 20 g p m to 110 g.p m during the test
period.
Figure 10
DOMESTIC SEWAGE - LARGE MOTEL
Period
Jan. 1955
Feb
March
April
May
June
'July
•Aug.
Sept
Oct.
Nov.
Dec.
Jan. 1956
Feb.
March
April
May
June
July
Aug.
Sept
Oct.
Nov.
Dec.
BOD
Influent
(mg/l)
187
164
137
211
171
173
174
145
—
127
264
169
216
200
222
190
164
171
152
136
120
149
166
175
Effluent
(mg/l)
10
12
7
25
9
8
49
30
—
10
7
11
18
17
13
16
15
13
4
8
10
21
11
12
Removal
(%)
94
93
95
88
94
95
72
79
—
92
97
93
91
91
94
91
91
92
97
94
91
86
93
93
SUSPENDED SOLIDS
Influent
(mg 1)
383
408
383
328
222
245
228
221
—
147
218
260

228
227
314
149
165
205
185
241
183
162
232
Effluent
(mg/l)
38
32
28
38
9
32
101
65
—
24
7
20
_
37
56
65
. 8
32
41
9
25
38
28
30
Removal
(%)
90
92
93
88
96
89
56
70
—
84
97
92
_
84
75
80
94
80
80
95
89
80
83
87
Sewage is pumped from a surge tank at 30 g p m Plant operation is intermittent.
'"VORTI-MIX" Aerator out of service
Figure 11
PHENOLIC WASTE WATER - OIL REFINERY
Period
Jan. Feb
1956
PHENOL
Influent
(mg/l)
180
Effluent
(mg/l)
0.4
Removal
(%)
99.8
SULFIDES
Influent
(mg '!)
40
Effluent
(mg/l)
0
Removal
(%)
100%
-------
-------
SEWAGE - INSTITUTIONAL
Date
9-30-54
30-25-54
10-30-54
11-16-54
3- 4-55
7-30-59
*10- 1-59
*'10- 1-59

Influent
(mg/l)
264
321
325
271
169
1830
593
593
BOD
Effluent
(mg/l)
92
240
21.0
205
14.0
690
44.0
36.0

Reduction
(%)
96 5
925
936
92.4
91 7
962
926
939
SUSPENDED SOLIDS
Influent
(mg 1)
117
301
274
268
125
4145
1016
1016
Effluent
(mg/l)
7.7
166
157
21 8
11 0
19.0
330
21.0
Reduction
(%)
43.4
945
94.3
91 9
91.2
995
96.7
97.9
*Raw Sewage and Effluent of "AERO-ACCELATQR" No 1
"Raw Sewage and Effluent of "AERO-ACCELATOR" No. 2
Figure 13
INSISTENTLY HIGH REMOVALS
)VER WIDE RANGE OF LOADINGS
/ITH LOW EFFLUENT BOD
'AERO-ACCELATOR"
unit
TRADITIONAL ACTIVATED SLUDGE (0.3-0.5)

-------
-------
A
MD>

! - f
I
f ;"(
; 'li
C
IF
•x
'$
0)
ii
f
T
(D
© The proper application of an "AERO-ACCELATOR" unit will depe
upon the strength and variability of the waste to be treated, and on t
results desired. Required design information includes the average a
peak flow rates, waste characteristics (BOD, suspended solids, pH, te
perature, and other criteria), and the desired effluent quality. The
data determine the necessary aeration and mixed liquor volumes wh
are based upon experience with numerous pilot and full-scale plan

<9 O O Provision of proper aeration volume and limitation of clarificat
area loading define the application of the "AERO-ACCELATC
unit. Detention period, in itself, is of no significance. Different si
of internal mechanisms can be installed in the same size ba:
in order to accommodate both the aeration and clarification requ
ment of a specific treatment problem.

9 O O Requirements likewise dictate the oxygenaticn capacity of
aeration unit, whether the "VORTI-MIX" or the "VORTAIR" ae
tor is selected. The design and flexibility in operation of each a«
tor maintain mixed-liquor dissolved oxygen at minimum tc
power consumption. Because adequate mixing is provided by
rotor, no dependence is placed upon air to accomplish mixing.
MODIFICATIONS
The "AERO-ACCELATOR" unit is offered with certain basic modifications
adapt to a wide variety of conditions and wastes.

The basic unit has been described under "Operation" and can be applied for non
activated sludge treatment of domestic sewage or wastes with a BOD of less tl
about 600 mg/l.

For stronger wastes, or for treatment of domestic sewage by "extended aeratic
the standard unit is modified so the geometrical proportions will provide the n
economical unit consistent with the waste and the process. In the modificat
TYPE I-O, the positions of aeration and clarification zones, are reversed.
change provides the required large aeration volume and relatively small clarifica'
area. By this means, loadings several times those permissible for the stand
"AERO-ACCELATOR" unit can be used without sacrificing any of the derr
strated advantages of effective activated sludge treatment. Strong wastes can
treated effectively and economically. The overall area required is considerably
than that of other comparable treatment systems.
Figure 9, Page 9, in the section under "Operation", illustrates the "AER(
ACCELATOR" unit, TYPE I-O.
-------
-------
Type 1-0
For sewage treatment, the "AERO-ACCELATOR" unit is preceded by a primary
clarifier with scum and sludge removal mechanisms. When the clarifier is designed
according to customary standards of engineers and regulatory agencies, advantage
is taken of economical BOD removal to decrease the loading and size of the "AERO
ACCELATOR" unit. Waste mixed-liquor solids can be returned to the primary
clarifier for thickening prior to sludge disposal.
Since the settleable or floatable solids content of many industrial wastes is either
very low or non-existent, pre-treatment is not always necessary. Such wastes can be
discharged directly to the"AERO-ACCELATOR" plant. However, if previous ex-
perience does not provide the necessary design information to establish all load
factors for efficient treatment, they should be established by pilot plant study.
Mechanisms are available for installation in either circular or square basins.
;r v'c^'-^'>sw^ fr^ii
... :->- ' >f!f^a
19
-------
-------
JL A
Cry of E///of ta/ce
E//;"of Lake, Ontario
Canada
45-Foot Diameter
Figure 20
Whippany Paper Board Con
Whippany, New Jersey
110-Foot Diameter
Figure 21
Mobil Oil Company
Ferndale, Washington
(2) 28-Foot, Standard
(1) 50-Foot, Type I-O

Kaanapali Development
Maui, Hawaii
47-Foot Diameter
Figure 23
-------
-------
Domestic and Industrial Plants
Shibaura Sewage

(8) 52-Feet Wide By

131-Feet Long
Whippany Paper Board Company '.
^^/hippany. New Jersey F~
^P75-Foot Diameter .~

c
Figure 25
City Sewage
Schwaebisch, Gmijnd
Germany

(2) 53-Foot Diameter
Figure 26

jH~-!-™ ^ff^f.^.^ .„,„- =•--.-— -•".'"*
r ~ - .- ,' « "•»
;? ±3
^3
i
^•'.f-.'--
^>~,."
,'V •"
"'*..•• '•
2. ^
.'•> j;
t
IftJ^V--^-.^'^
fr^'y.'"
fe,. ~\>'
-%
- r*-.J~fic.t.
l —1 •
>-ii.. '>*^.-.#i^'rf-c.
-A

^^
l^ft-.- "**
/fy of Litchfield

Litchfield, Minnesota

(2) 47-Foot Diameter
'"^. . . -- — O ""
-------
-------
F
with "VORTI-MIX" Aers
.^HANDRAIL
DRIVE i—ADJUSTABLE GATES
TO CONTROL CIRCULATION
SLUDGE.

AIR
-A—^L^l^- < 'uTTTTZinS-^-^^
). j. ' ! »i
JRAIN _ Lj J V '-—-I— . INFLUENT
•"cr: —"^ » —• 1
TT > *• ^..|
Figure 28

APPROXIMATE DIMENSIONS FOR STANDARD

Based on these assumed conditions- 200 mg/l BOD in Raw Sewage • 30% BOD removal in Primary • 12% Oxygen

Absorption Efficiency • Maximum Flow — 200% of Avg.'Temp of waste = 29°C • Mixed Liquor DO =: 2 Mg/l

• O Saturation Value — 95% , that of water • O.- Transfer r-actor, ai , = 0.95.
Average
Flow
g.p.d.
100,000
150,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
1,000,000
1,250,000
1,500,000
1,750,000
2,000,000
2,250,000
2,500,000
2,750,000
3,000,000
Basin Dimensions
Diameter
1 5'-0"
1 9'-0"
2 1 '-0"
25'-0"
29'-0"
33'-0"
36'-0"
38'-0"
42' -Q"
44'-0"
47' -Q"
52'-0"
57' -0"
62' -Q"
67'-0"
72'-0"
77'-0"
80'-0"
84'-0"
S.L.D.
1 1 '-6"
1 1 '-6"
1 2'-0"
1 3'-0"
13'-3"
1 3'-6"
1 4'-0"
1 4'-0"
1 5'-0"
15'-0"
16'-0"
16'-6"
1 7'-0"
1 8'-0"
' 18'-6"
1 9'-0"
19'-3"
1 9'-3"
20' -0"
Freeboard
T-6"
T-6"
1 '-6"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-Q"
2'-0"
2'-0"
2'-0"
Diam. at
Toe of Fill
1 O'-O"
lO'-O"
12'-0"
14'-6"
1 6'-6"
1 8'-6"
20'-6"
20'-6"
24'-0"
24'-0"
26'-6"
30'-0"
33'-0"
36'-6"
42'-0"
45'-0"
sr-6"
51 '-6"
1 55^0"
Clarification
Area sq. ft.
144
250
302
420
566
723
864
980
1184
1320
1467
1777
2118
2528
2818
3242
3493
3862
4253
Total
Volume
gal.
14240
20600
26820
40950
54050
69000
85900
90000
121200
126800
1 58000
199000
242000
304000
381000
444000
534000
555000
645000
18
-------
-------
PLAN
Figure 29
KERO-ACCELATOR" UNIT
Mixed Liquor
Volume Gal.
9940
13100
17760
26790
35000
44650
56800
57000
82100
82300
103150
132000
162000
210000
H)00
DOO
403000
410000
485000
@ 3,000 mg/IMLSS
Ibs. MLSS
250
330
440
670
880
1120
1420
1420
2050
2060
2580
3310
4060
5250
6820
8060
10100
10300
12140
Ib. BOD /day
/Ib. MLSS
0.47
0.54
0.53
0.52
0.54
0.52
0.49
0.57
0.46
0.51
0.45
0.44
0.43
0.39
0.34
0.33
0.29
0.31
0.42
Aerator
Drive
HP
1
V/2
1
3
5
7'/2
7'/2
7'/2
10
10
15
15
15
20
25
25
30
40
40
Air Required (Not including Standby)
Volume
scfm
32
48
64
96
128
160
192
220
256
286
320
400
480
560
640
720
800
880
960
Pressure
psig
5.0
5.0
5.5
5.5
6.0
6.0
6.0
6.0
6.0
6.0
6.5
6.5
7.0
7.0
7.5
7.5
7.5
7.5
8.0
Blower
HP
2
3
3
5
7'/2
7'/2
7'/2
10
10
10
15
15
20
30
40
40
40
40
50
Average
Flow
g.p.d.
100,000
150,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
1 ,000,000
1,250,000
1,500,000
1,750,000
2,000,000
2,250,000
2,500,000
2,750,000
3,000,000
-------
-------
"AERO-ACCELATOR" unit
with "VORTAIR" Aerator
APPROXIMATE DIMENSIONS F
Based on these assumed conditions: 200 mg/l BOD in Raw Sewage • 30% BOD
removal in Primary • Maximum Flow = 200% of Avg. • Temp, of waste = 29°C
• Mixed Liquor DO = 2 Mg.'l • O2 Saturation Value = 95%, that of water • O2 Transfer Factor, of , = 0.95.
Average
Flow
g.p.d.
100,000
150,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
1,000,000
1,250,000
1,500,000
1,750,000
2,000,000
2,250,000
2,500,000
2,750,000
3,000,000
Basin Dimensions
Diameter
16'-0"
19'-0"
22' -0"
26'-0"
30'-0"
35'-0"
39'-0"
45'-0"
47' -0"
49'-0"
54'-0"
60'-0"
65'-6"
74'-0"
78'-0"
83'-6"
87'-6"
90'-0"
93'-0"
S.L.D.
lO'-O"
lO'-O"
1 0'-O"
1 1 '-0"
11 '-0"
1 2'-0"
12'-0"
1 3'-0"
1 3'-0"
1 3'-0"
1 3'-0"
14'-0"
1 5'-0"
15'-0"
1 6'-0"
1 6'-0"
1 7'-0"
1 7'-0"
1 8'-0"
Freeboard
2'-0"
2'-0"
2'-0"
2'-0"
2'-0"
2'-6"
2'-6"
3'-0"
3'-0"
3'-0"
3'-0"
3'-0"
3'-0"
3'-6"
3'-6"
3'-6"
3'-6"
3'-6"
4'-0"
Diam. at
Toe of Fill
8'-6"
lO'-O"
ir-6"
1 4'-6"
1 6'-0"
20'-0"
24'-0"
32'-0"
32'-0"
32'-0"
37' -6"
42'-6"
47"-0"
55'-0"
58'-0"
63'-0"
66'-0"
66'-0"
69'-0"
20
-------
-------
j— HANDRAIL
ADJUSTABLE GATES
/ TO CONTROL CJRCULJTION
Figure 30
STANDARD "AERO-ACCELATOR" UNIT
4

Clarification
Area sq. ft.
157
220
294
418
564
748
848
1018
1163
1313
1435
1953
2113
2491
^54
3144
3550
3898
4242
Total
Volume
gal.
12850
17350
22400
35100
43600
66500
85000
134500
141000
146200
183500
248000
306000
412000
487500
560000
656000
670000
773000

Mixed Liquor
Volume Gal.
8150
10780
13650
22600
26750
41400
56300
1 00000
102000
102200
135500
182000
227000
319000
380000
444000
524000
525000
614000
@ 3,000
|bs. MLSS
205
270
340
575
670
1035
1410
2500
2550
2560
3390
4550
5670
8000
9500
11100
13100
13200
15300
ng /I MLSS
Ib. BOD /day
/Ib. MLSS
0.58
0.65
0.69
0.61
0.70
0.57
0.50
0.33
0.37
0.41
0.34
0.32
0.31
0.26
0.25
0.24
0.22
0.24
0.23
Aerator
Drive
HP
3
5
5
7'/2
10
10
15
20
20
20
25
30
30
40
50
50
50
60
75
Average
Flow
g.p.d.
100,000
150,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000
1 ,000,000
1,250,000
1,500,000
1,750,000
2,000,000
2,250,000
2,500,000
2,750,000
3,000,000
-------
-------

ID
• • From the 275 successful installations, the following are typ
of the acceptance of "AERO-ACCELATOR" units. The wide-spn
geographical locations with designs by many consulting engineers,
various types of sewage and industrial wastes, and the utilization
proper modifications, all attest to acceptance by progressive engine
Location
Arkansas, Sherwood — City of Sherwood
California, Edgemont — fdgemont Community
Service District
Florida, Broward County —
Cooper Colony Estates
Hawaii, Island of Maui —
Kaanapali Development
Illinois, Frankfort —
City of Frankfort
Kentucky, Louisville —
Whispering Hills Subdivision
Massachusetts, SundeHand —
City of Sunderland
Michigan, Kalamazoo —
Kalamazoo Paper Company
Minnesota, Litchfield — (2)
City of Litchfield
Minnesota, Rose Port —
Great Northern Oil Company
Nebraska, Chappell —
City of Chappell
New Jersey, Hamilton Township — (2)
Yardville — Groveville Plant
New Jersey, Whippany —
Whippany Paper Company

New York, Monticello — (2)
Lake Louise Marie
North Carolina, Charlotte —
Lance Inc.
North Carolina, Shelby— (2)
Pittsburgh Plate Glass Co.
Oklahoma, Okmulgee —
Phillips Petroleum Company
Pennsylvania, Allegheny County —
Allegheny Valley Joint Sewage Authority
Size
30'-0" dia. x
16'-6" SLD
35'-0" dia. x
13'-6" SLD
30'-0"dia. x
14'-0" SLD
47'-0" dia. x
16'-0" SLD
23'-0" dia. x
13'-3" SLD
30'-0" dia. x
13'-3" SLD
29' -0" dia. x
16'-6" SLD
42' -0" dia. x
19'-6" SLD
47'-0" dia. x
16'-0" SLD
60'-0" dia. x
18'-3" SLD
25'-0" dia. x
13'-6" SLD
28'-0" dia. x
12'-6" SLD
1 lO'-O" dia. x
22'-6" SLD
175'-0" dia. x
29' -Q" SLD
29' -Q" dia. x
13'-3" SLD
3T-0" dia. x
16'-6" SLD
35'-0" dia. x
20'-0" SLD
34'-0" dia. x
16'-0" SLD
27'-6" dia. x
13'-6" SLD
46'-0" dia. x
16'-0" SLD
Waste
Sewage
Sewage
Sewage
Sewage
Sewage
Sewage
Sewage
De-inking
Waste
Sewage
Oil Refining
Waste
Sewage
Sewage
Board Mill
Waste

Sewage
Sewage
Fibreglass
Waste
Fibreglass
Waste
Oil Refining
Waste
Sewage
Type
I-O
Std.
Std.
Std.
Std.
Std.
I-O
I-O
Std.
Std.
Std.
Std.
Std.
Std.
I-O
I-O
I-O
Std.
Std.
Std.
-------
-------
Location
Size
Waste
Type
Washington, Ferndale —
Mobil Oil Company
(2)

Canada, Elliot Lake, Ontario —
City of Elliot Lake
Cuba, Loma de Tierra —
United States Rubber Company, Ltd.
France, Elbeuf, Seine-lnferieure (2)
Ville d' Elbeuf
Germany, Koln —
Esso AG Raffinerie
Germany, Stadt Fuerth —
City - Sewage
Japan, Otaru City, Hokkaido (4)
City - Sewage
Japan, Tokyo, Shibaura Plant (8)
City - Sewage
Malaya, Singapore —
Sembawang Hills Estate
Mexico, La Galarza, Puebla
Compania Ron Bacardi
Spain, Madrid
Alcala de Henares Airport
Sweden, Vintrie
Bunkeflo Community
^
50'-0'
22' -6'
27' -6'
1 4'-0'
45'-0'
16'-3'
1 4'-6'
1T-6'
65'-6'
1 7'-6'

95'-0'
48' -0'
1 6'-0'
52' -6
13T-0
25'-0'
1 3'-3'
1 3'-0'
9'-6'
1 4'-0'
20' -0'
12'-0'
^—
__- — -~z^.
' dia. x
'SLD
dia. x
" SLD
' dia. x
' SLD
' dia. x
' SLD
' dia.
' dia.

' dia.
' dia. x
' SLD
" wide x
" long
' dia. x
' SLD
dia. x
' SLD

' dia. x
' SLD
—
^r
Oil Refining
(Phenol)

Sewage
Sewage
Sewage
Oil Refinery
Waste
Sewage
Sewage
Sewage
Sewage
Sewage
Sewage

Std.
Std.
Std.
Std.
Std.

Std.
Std.
Std.
Std.
I-O
.Std.

Std.
-------
-------
GENERAL
A
/I IN
26
There shall be furnished for installation in each (dia, squan
rectangular), side liquor depth tank with freeboa
an "AERO-ACCELATOR" mechanism for complete mixing and biological oxid
tion of sewage or waste liquors by intimate contact with aerobic organisms in c
activated sludge developed and maintained in an aeration compartment, and f
separation of treated liquid from the activated slurry in a separation compartmer
Each unit shall be capable of treating an average flow rate of 9-P-i"
and a peak flow of g.p.m.

"AERO-ACCELATOR" MECHANISM
There shall be furnished all structural and sheet steel to form the inner and outi
draft tubes, recirculation control gates, hood, support columns or rafters, a bride
consisting of structural beams, checkered plate walkway, handrail and base pla
for mounting the drive mechanism at the center of the basin. All steel plates ar
shapes shall be furnished knocked down', arranged for field welding by others.
The hood shall form a mixing and aeration compartment for the incoming sewag
or waste and activated sludge. The draft tubes shall form recirculation zones an
a separation compartment.

AERATOR MECHANISM-Use ONE

USING COMPRESSED AIR
There shall be furnished with each "AERO-ACCELATOR" mechanism a "VORT
MIX" Aerator, including a h.p. variable speed drive and reduce
couplings, shaft, impeller with straight vertical blades, air sparge ring, support fc
sparge ring and all air piping and supports within the basin.
USING ATMOSPHERIC AIR
There shall be furnished with each
AIR" aerator including a
'AERO-ACCELATOR" mechanism a "VORT
horsepower constant/variable speed drive an
reducer, couplings, shaft and impeller(s) with straight vertical blades. The aerate
shall be mounted in relation to the surface of the waste and rotated so as to drav
large quantities of air from the atmosphere into the liquid.
SLUDGE DISCHARGE
There shall be furnished a waste sludge discharge line consisting of either (a) pipini
of suitable size to pass through the basin wall and a timer operated blow-off valvi
or (b) an air lift type pump of suitable size including all sludge piping and ai
piping within the basin, a timer, solenoid valve and needle valve for the air line
and necessary supports.
-------
MOTOR CONTROLS
There shall be furnished an across-the-line starter in NEMA
enclosure for phase, cycle, volt current provid-
ing over-load and undervoltage protection There shall also be furnished an auxiliary
push-button station in NEMA enclosure and a push-button station
with locking device on the stop lever in NEMA 4 enclosure for mounting at the
drive.

BLOWERS required if compressed air and "VORTI-MIX" aerator are used.
There shall be furnished motor drive blowers for supplying air at a pressure of
pounds per square inch, as follows:
unit(s) at cubic feet per minute driven by
a horsepower motor.
One unit at cubic feet per minute driven by a
horsepower variable speed drive.
One unit at cubic feet per minute driven by a
horsepower motor for standby service.
There shall be furnished with the blowers, necessary flexible connections, check
valves, re'ief valves, inlet filter silencers, belt guards as required, 0-10 p.s.i.
pressure gauge, indicating c.f.m. gauge and suitable orifice plate and flanges.
There shall be furnished across-the-line starters in NEMA enclosure
for phase, cycle, volt current overload and un-
dervoltage protection and push-button stations in NEMA enclosure.

PAINTINC7
Before application of paint, ail surfaces shall be dry and free of rust or grease.
Structural steel shall be given a shop coat of chromic metal primer or equal.

SERVICE ENGINEER
There shall be furnished by the equipment manufacturer the services of an engineer
to check the completed installation, place the equipment in operation, and instruct
the operators in the correct operation and maintenance procedures.
-------
FULLER
ENGINEERED PRODUCTS FOR INDUSTRY...
AIR HANDLING EQUIPMENT . . . Fuller rotary compressors, Sutorbilt blowers ai
Lehigh- fans
PNEUMATIC MATERIALS CONVEYING SYSTEMS . . . Airveyor, Airslide^ at
Fuller-Kinyon conveying s'ystems
POLLUTION CONTROL EQUIPMENT . . . Dracco8 dust collectors, Infilco water ar
sewage treatment systems
HEAVY PROCESSING MACHINERY AND SYSTEMS . . . Traylor crushers, kil
and mills, Fuller grate coolers, fluid bed reactors and Fuller specialized equipment f
the mineral industries
Offices in principal cities of the United States and Canada

INFILCO
FULLER COMPANY/GENERAL AMERICAN TRANSPORTATION CORPORATION

P.O. BOX 5O33, TUCSON. ARIZONA B57O3. TELEPHONE 603/623-5401 R ©
\a*

PRINTED IN U S.A. 2M
-------
BIOLOGICAL REMOVAL OF PHOSPHORUS

Phosphorus removal by activated sludge treatment is commonly

limited to 30-50 per cent by considerations involving bacterial metab-

olism, the variable quantity of organic matter stabilized by the conven-

tional system and its modifications, and the waste-sludge disposal

methods in current use.

Much higher removals are obtained at a few locations and inten-

sive study of these plants is defining the influence of several opera-

tional factors on what is termed "luxury uptake" of phosphorus. Among

these are the necessity for maintenance of a minimum aeration-basin

^dissolved oxygen concentration of 2 mg/1, rapid removal of solids from

^the final clarifier to minimize anaerobic release of phosphorus, and

provision of uniform load.

Design of the AERO-ACCELATOR unit is advantageous on all these

1. The oxygen necessary to maintain any desired concentration

of mixed-liquor dissolved oxygen is efficiently and econo-

mically supplied by its turbine aerator component.

2. Its integral solids separation and recycle systems eliminate

the deficiencies of separate final clarification. The acti-

vated sludge is constantly being circulated at a high rate

from the solids separation zone into the aeration zone.

3. Its complete-mixing design minimizes load variation within

the treatment system.
-------
— offering the broadest, most complete line of equipment for water/waste/
reuse systems, ranging from small "package" units to multi-million gallon-
per-day treatment plants.
— continually adapting to the changing needs of public works and industry.
(We believe you will be most interested in the attached small insert, "What
has Infilco Done Lately in Solving Pollution Problems?")
— In working with your problems, with your engineers, our sales engineers
have at their disposal all of the resources, technical skills and manufacturing
facilities of the General American Transportation Corporation of which Fuller
Company -including the Infilco Products group-is a part. Supplementary
resources include air pollution control equipment and material handling sys-
tems by the Fuller Company; research, testing, development and design
through General American Research and Development; and manufacturing
plants strategically located throughout the country to allow reduced trans-
portation costs and assure on-time deliveries. The GATX Plate and Welding
Division assures united installation responsibility, for customers who desire
this service.
NEAR YOU
— As you will wish to initiate action and maintain communication regarding
progress, it is important to have service readily available. Sales, service, and
application engineers in regional and branch offices stand ready to serve you
in the Lake Michigan area.
-------
-------
the mineral industries
Offices in principal cities of the United States and Canada _ _ _ mem^j
GATX
COMPANY Hr™SS^S
CO PRODUCTS P.O BOX 5O33. TUCSON. ARIZONA 857O3. TELEPHONE 6O2/6S3-54O1
:ULLER
ENGINEERED PRODUCTS FOR INDUSTRY...
"XIR HANDLING EQUIPMENT . . . Fuller rotary compressors, Sutorbilt blowers and " F"
.ehigh1 fans .. M

r
r
L
3NEUMATIC MATERIALS CONVEYING SYSTEMS . . . Airveyor, Airslide8 and ,
Fuller-Kinyon conveying systems |__

POLLUTION CONTROL EQUIPMENT . . . Dracco3 dust collectors, Infilco water and L r
sewage treatment systems i
HEAVY PROCESSING MACHINERY AND SYSTEMS . . . Traylor crushers, kilns
and mills, Fuller grate coolers, fluid bed reactors and Fuller specialized equipment for
L
L
L
-------
-------
- —"J ^

fr
PHOSPHATE LEVEL CONTROL IN EFFLUENTS
One of the principal factors in the Eutrophication, or

aging of lakes, and rivers has been shown to be the phosphate

content of waters discharged into the lake or river.

Substantial control of the phosphate content of effluents

is possible using ....

ACCOFLOC 6774-C
ACCOFLOC 6793-C
ACCOFLOC 6793-D

The ACCOFLOC products are micaceous materials with a

platelet molecular structure. The large surface area of such

materials is used as a basis for the adsorption, flocculation

and removal of phosphate.
-------
-------
o
CHARACTERISTICS OF ACCOFLOC g

ACCOFLOC is mainly inorganic in nature, with organic >x)
K
O
Content of less than 10%. It is non-toxic, disperses rapidly £g

in water, and will give easily pumpable suspensions at solids ^

contents as high as 8% or 80,000 ppm. w

S
A simple agitator will be sufficient to effect dispersion o

and^uspension. The addition of ACCOFLOCS in suspension is ^
CO

recommended for easy control. en

The ACCOFLOC flocculates readily in municipal wastes at 3

all points in the processing of the waste, and have been §

L I
observed to speed the rate of settling of the solids in the n

a
K
-------
-------
EFFICIENCY OF REMOVAL OF PHOSPHATE J>
f

Suspensions of ACCOFLOC added to Municipal waste
removed phosphate as shown on the attached graphs.
o
PROCEDURE v.,
—...--..- JJ
t-l

As the sewage was agitated on a magnetic mixer, the £H

ACCOFLOC was added as a 1% suspension. Mixing was continued £j

for 15 minutes. Sample was removed and analyzed for phosphate. ^
M
n
o
o
r1
t^
o
M
a

n
o
-------
-------
PHOSPHATE REMOVAL FROM "MIXED LIQUOR"
CHICAGO METROPOLITAN SANITARY DISTRICT

HANOVER PARK PLANT
ou
n
o
t~^
tr
o
n
o
en
t-3
H
H
3
O
en
K3

H
3
I
H
n
o
tr1
tr1
O
O
O
- 300
200
PPM ADDITIVE
-------
-------
PHOSPHATE REMOVAL FROM FINAL EFFLUENT
CHICAGO METROPOLITAN SANITARY DISTRICT
HANOVER PARK PLANT
40
30
.e
\ort
5 _
~
20
10

300
100
PPM ADDITIVE
200
-------
RATE OF REMOVAL OF PHOSPHATE

ACCOFLOC, in suspension, was added to a sewage sample

and agitated on a magnetic mixer.

Samples were removed at intervals, as indicated on

the graph, vacuum filtered, and analyzed for phosphate.

ACCO 6793-D was used, at a level sufficient to reduce

the phosphate content to 20% of its original value, thus
73

effecting 80% removal. :>
Ef£C

Total Removal = 19.5 - 3.4 = 16.1 ppm
in
Removal after 2 minutes = 19.5 - 7.5 = 12.0 ppm K
rir to
•-3

Removal after 5 minutes = 19.5 - 3.4 = 16.1 ppm Tj

62.1% of the phosphate was removed after only 2 minutes of f-~
n

reaction. Reaction was complete (82.6% removal) in 5 minutes. >-<

Higher removals, and lower phosphate content effluents *'

could be realized by use of higher levels of ACCOFLOC. r
r
o
M
a

n
-------
RATE OF REMOVAL OF PHOSPHATE FROM

CHICAGO METROPOLITAN SANITARY DISTRICT

HANOVER PARK PLANT

ppm
soluble
osn^jrous
1: l:'l£i ii:k: JT- Mj^diiiikimil^iiiiili^L
3£Qi3lr:g"Srar":ACHO!-.i£7-93:-H^f

Siis-ci en sdlcm-'iafddeH; .^

-------
STABILITY OF SETTLED ACCOFLOC

Several biological methods of phosphate removal tend

to release the phosphate after settling.

ACCOFLOC was left in contact with the sewage under

anaerobic conditions and continuous agitation for extended

periods. Samples were taken at regular intervals and

a;^fcyzed for phosphate content.

No release or re-solution of phosphate was observed

with contact times of up to 30 hours.
-------
STABILITY OF SETTLED PHOSPHATE RICH

ACCOFLOC
CHICAGO METROPOLITAN SANITARY DISTRICT
40
— Lrz: .
ppm
soluble
pto
sphorouEft^
as =
PO,
^"ijT'i.i.1.. ri"~zir" _.'t ~ i * -+ —. i r -i ™~-_ j ^' _r^_ * ™ ~~ — | t -—--—-—^~"~' ' * izr —~~^ J t
._r_t „ iTrri_LT._rit-~ —. -1^.T. ^-\~r 1 .i- .l -i-,-,.~'r^n-Tri-TL._~. j. ^7Jc_"_r"L"-"H"iTi' E.i.-_t.i._.-"ii^-"--" i"_ri-Z-^-T"~^_r^-~-i^"-inr^ ~t_Lzrc
1-7—*f~- *"• r •-* ~- <-"-—— -^" " i ~ -t -' *.,.- L"I L~L1." . li* r '. ~~L^i - J."_~.^" I"!!.{' ™*11,", ~ t>~^ ~TT-— If "j r~^ll"Z~Z.ll"_,~ _~T~~" ' |.I~ r -^—— - •-^-— ^- -~- •—---—^ ^_^^f
^^2p^;^|M^§ri^i£^i:^^i^^M^
r-~^-:r'?;iir£::^r;^
20
10
HANOVER PARK PLANT .
.^ISi^l^aiJiLl^

i-
-1— p-
i^^::ill:jMi^llMlM
i^hifkl^^ilEMP^
|:-H-:-f-v;-:,f--^-^-:|-E:::-t--3
^
.I'.i^r^-jL-::-'-.-!:!'.1::.:^."!-".-::'..!:'!:1:^.
o[±h_i.
i o
20
30
-------
EFFECT ON SETTLING

Laboratory studies indicate that substantial improvement

in settling characteristics can be expected by adding ACCOFLOC

6793-D (see following graphs).

With treatment levels of 100 ppm and a low wastage in

activated sludge plant, an equilibrium level of several

hundred parts per million would result. As such levels

considerable improvement in the settling characteristics

can be anticipated.
-------
-------
FREE SETTLING RATES.

CHICAGO METROPOLITAN SANITARY DISTRICT

HANOVER PARK PLANT
1000
n
o
o
+3
tr1
O
O
ffi
O
ffi
>
i^
W
s
o

en
K;
en
H
W
2
I
M
n
n
o
o
M
O

n
o
-------
EFFECT ON SLUDGE VOLUME INDEX

CHICAGO METROPOLITAN SANITARY DISTRICT

HANOVER PARK PLANT
££S8r;££s!3-D
O
O
O
^
f
O
O
en
^
ffi

O
O
2
500
1000
1500
-------
APPENDIX
PHOSPHATE ANALYSIS

All charts and data show soluble phosphates expressed

as ortho-phosphate.

SAMPLE PREPARATION

Sample was filtered through WHATMAN No. 1 paper. 50

mis. of the sample and 2.0 mis of 12 N sulfuric acid were

boiled for 30 mins., then cooled to room temperature.

10 mis of molybdate-vanadate solution was added to

this sample. Color was allowed to develop for 20 minutes,

optical density was measured at 440 milli-microns, and was

compared to optical density of known standards of phosphate,

Phosphate content was expressed as parts per million

phosphate.
-------
Frorn
Raw
Sewage...
*" -* --
complete
to
PolisHed
Water
t
•eptune
FLOG
INCORPORATED
WATER AND WASTE WATER TREATMENT DIVISION OF
NEPTUNE METER COMPANY
P.O.BOX 612 • 1965 AIRPORT ROAD • CORVALLtS, OREGON 97330
Copyright 1967 Neptune MicroFLOC Inc.
j
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Meptune MicroFLOC has already intro-
iuced to the waste treatment field the con-
cept of packaged effluent clarifying and
jolishing equipment through its Model SP
^ecla-Mate unit (bulletin KL-4560).
Now in Recla-Pak, Neptune Micro-
lant frequently is degraded by the dis-
:harge of large quantities of solids in the
slant effluent. These discharges may be
:aused by surges in the raw sewage flow
vhich overload the conventional package
slant settling basin, by mechanical failures
if the sludge collection and return system,
>r by failure of the plant operator to waste
.dequate quantities of sludge.
Recla-Pak overcomes all of these short -
:omings. Extreme fluctuations in raw sew-
ige flow are absorbed in the combination
.eration-surge storage tank. This prevents
low Jittrges from upsetting the settling
jroc^Jr The simple, positive Recla-Pak
•ettling and sludge return system mini-
nizes chances for sludge return failures.
The mixed-media filter will trap solids
vhich escape from the settling process.
Neptune MicroFLOC's advanced research work has been ap-
plied to the polishing of sewage plant effluent with the result
that more than 98 % of raw sewage suspended solids and BOD
can now be removed with little increase in operating cost. No
chemical coagulants are required. In most cases, clarity of the
final effluent exceeds standards of the USPHS for drinking water.
Two MicroFLOC developments are key factors in this pro-
cess. These are the tube settler which permits the efficient re-
moval of solids within the confines of a relatively small tank and
the mixed-media filter which removes remaining solids at high
flow rates.
These developments enable communities to meet the most
critical standards of sewage treatment with modest capital ex-
penditures, low operating costs, and assurance of returning a
high quality effluent to the receiving stream.
V
More and more water pollution control agencies are setting
strict standards limiting the nutrient content of even
low solids and BOD effluents. Supplemental equipment is
available to treat the effluent either from extended aera-
tion or contact stabilization plants as well as the Recla-Pak
to produce effluent phosphate concentrations of less than
0.5 mg/1. Chemical precipitation of the phosphates with
alum is followed by tube clarification and mixed-media
filtration to produce an effluent low in phosphate. This
equipment is available with Recla-Pak as a modular addi-
tion to the basic plant.
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w
tfAGE
•/: MIXED i:
is; MEDIA T
•;'/FILTER-'-
FILTER CYCLE
BACKWASH
fter ^kpng through a bar screen, sewage enters the
irati^Kasin where it is subjected to long-term aerobic
ological treatment. This biological treatment converts
early all of the objectionable organic materials in the
iw sewage to biological solids. The aeration period con-
;rts the biological solids formed to a relatively inert
mdition, eliminating the need for elaborate sludge
gestion facilities.
The aeration tank also serves as a surge storage tank
r allowing the water level to vary so that the settling
iid filtration units operate with controlled variations in
aw rate.
Water flows from the aeration tank through the unique
rbe settling device. This settling device consists of a
lultiplicity of inclined shallow tubes. The biological
>lids formed in the aeration tank are effectively re-
moved in such a settling unit with only a few minutes'
stention time. The solids are continuously removed
om the settling unit by gravity and returned to the
jration process to maintain adequate biological activity
i insure a high degree of biological treatment.

There is no sludge return pump to fail — a weak link
the design of most package plants. The very short resi-
mce time in the settler eliminates the problems caused
r the long settling periods usually associated with pack-
'e plants. In other plants, septic conditions can develop
the settling tank with the result that sludge will float
the surface and be lost in the plant effluent.
Any
ng
articulate matter which should escape the set-
removed by passing the effluent through a
filter. The filter is graded from coarse to
le in the direction of flow to increase the amount of
idge which may be stored in the filter, and to provide
eater solids removal than would be provided by a plain
nd filter. The filter effluent is pumped to the backwash
jrage tank which also serves as a chlorine contact tank.
The final plant effluent overflows from this basin.
Recla-Pak effluent is used for backwashing the filter.
Backwash is automatic when a pressure sensor detects
high headloss across the filter. The backwash water is dis-
charged to the sludge wasting tank and allowed to settle.
The supernatant from the sludge wasting tank is then
recycled to the aeration chamber. The solids removed
from the system by this backwash cycle greatly reduce
the frequency with which sludge must be transferred
from the aeration basin to the sludge holding tank. Dur-
ing backwash, the incoming raw sewage flow is stored in
the combined aeration-surge storage chamber. Scum is
transferred to the aeration tank automatically during the
backwash cycle.
The backwash storage-chlorine contact tank and sludge
wasting tank are integral parts of the compact Recla-Pak
structure. All required tankage is contained in a single,
compact, rectangular, factory-assembled Recla-Pak unit.
When treating domestic sewage, Recla-Pak consistently
provides a final effluent BOD and suspended solids of
less than 5 mg/1. The low effluent turbidity (usually less
than the drinking water standard of 5 JU) improves the
efficiency of effluent chlorination and enables essentially
complete removal of coliform bacteria. Recla-Pak com-
bines the best features of biological treatment package
plants with all the benefits of effluent filtration. (For im-
proving the quality of existing package plant installa-
tions, use Recla-Mate as described in bulletin KL-4560.)
Recla-Pak provides a higher degree of treatment and a
higher degree of reliability than conventional package
plants while decreasing plant space requirements.
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3 - 71 -n' •'
„ .-Jj =,«/.:.
*IERALj«Under this section of the specifications, the contractor
1 fui^^B and install a factory-built sewage treatment plant
i a caflrcity of gpd which shall incorporate biological
age treatment and effluent clarification and filtration. Screen-
of raw sewage, sludge storage, hydraulic surge storage capacity,
>rine contact time, and filter backwash water storage shall all
i part of the package plant. The other principal items of equip-
it shall include a rotary blower complete with necessary motor
controls, air diffusers, filter effluent and backv. ash pumps, and
internal piping. The plant shall be similar and equal to Model
- manufactured by Neptune MicroFLOC, Inc., 1965 Air-
t Road, Corvallis, Oregon.
'he plant is to provide an average reduction of 98% or more of
BOD and suspended solids normally present in raw domestic
•age. Effluent filtration must be provided as a part of the process
Drotect against plant upsets and shall function satisfactorily
n during plant upsets. Suppliers other than the above-named
ipany wishing to quote on equipment in this section shall sub-
detail drawings of the proposed equipment and suitable evi-
ice of experience and results to the engineer and shall obtain his
tten approval to quote at least ten (10) days prior to bid
ning.
:RATION: The plant shall be capable of treating gallons
day of raw sanitary sewage with an organic loading of
mds of five-day BOD per day. The maximum design hourly flow
11 be gph with the maximum flow during a four-hour
iod being gallons.
'he raw sewage shall pass through a bar screen to an aeration
c. The liquid level in the aeration tank will be allowed to vary
sercent from a minimum depth of 7.5 feet to provide storage
lydraulic surges and storage of the influent during the periods
;n the filter is backwashing. The mixed liquor solids are to be
arated in a clarifier which is an integral part of the aeration
mber. The clarifier shall be arranged so as to provide for con-
lous gravity return of solids to the aeration tank and is to pro-
2 settling surface area of at least one square foot per 100 gallons
day at nominal plant capacity. The clarifier shall provide a
of less than 50 at all times to ensure proper
ns for sedimentation.
: clarifier shall be a filter containing a mixed-media
aration bed, graded coarse to fine in the direction of flow so as
iptimize sludge storage and to provide optimum solids removal.
low from the filter shall be to the backwash storage tank which
1 provide sufficient storage of filtered effluent for backwashing
for minimum one-hour chlorine contact at rated flow, and shall
ude means for overflow of the final effluent.
"'he backwash cycle shall be initiated automatically by headloss
oss the filter. Manual backwash means also shall be provided.
ring backwash, the material removed from the filter shall flow
he sludge storage tank. Means shall be provided for transfer of
sludge from the aeration tank to the sludge storage tank so that
the mixed liquor solids can be readily maintained in the proper
range The supernatant from the sludge storage tank shall be de-
canted to the aeration chamber.
CONSTRUCTION DETAILS: The package plant shall be factory-
built, and of the size and shape shown on the plans. Mechanical
simplicity of the plant is deemed important All components shall
be readily accessible for maintenance. The unit shall be designed
for installation below grade. All structural shapes shall be struc-
tural grade steel not less than ^i-inch thick.
The filter shall contain a 30 inch deep mixed-media separation
bed composed of three or more materials of different specific
gravity and providing a uniformly tapering void distribution from
coarse to fine in the direction of flow. Particle sizes shall vary from
0.15mm to 2.0mm.
Internal and external surface preparation and painting, to be
performed at the manufacturer's plant, shall include coal tar epoxy
to a thickness of 15 mils.
The filter flow rate is to be controlled by a float valve on the
effluent side of the filter pump. The float valve is to operate on the
level of water above the filter to provide a maximum filter flow rate
of 150 percent of the average nominal daily flow rate. The filter
pump shall he protected by a float-activated switch.
A control panel shall be furnished and shall include means of
automatically programming backwash when filter headloss reaches
a preset level, one backwash indicating light, and one pushbutton
switch for manual backwash actuation. The control panel shall also
include motor starters for blower, effluent pump and backwash
pump motors: pressure gauge (headloss); and pressure switch.
The control panel shall be pre-wired in accordance with NEC
and CSA standards and shall include a suitable breaker device to
receive power input as shown on plans. All exposed electrical de-
vices shall be weather-proof according to NEMA standards. All
motors shall be totally enclosed.
The backwash storage tank shall provide water for filter back-
washing and shall include a pump suction line. The tank shall be
provided with a float-actuated electrical switch with separately
adjustable trip and reset points. The switch shall provide pump
protection during backwash.
PERFORMANCE GUARANTEE: Contractor shall guarantee that the
plant will perform satisfactorily to produce an effluent in accord
with the specification standards. The effluent clarifying and pol-
ishing system shall be satisfactorily designed to assure that the
system will perform continuously within the normal raw sewage
loading conditions specified.
EQUIPMENT STARTUP: Contractor shall provide the services of a
factory-trained service man for a period of . . days to check out and
start the equipment and to instruct the operators in its operation.
Neptune MicroFLOC equipment covered by patents and patents
pending.
Recla-Pak—Basic Plant Data

Model Capacity Total Length* Weight
Number GPD Horsepower Feet Thousand Ibs
LA- n
LA- 16
LA-20
LA-25
LA- 30
LA-35
LA-40
LA-45
LA?50
12,000
16,000
20,000
25,000
30,000
35,000
40,000
45-.000
50,000
11
11
13'
14
14
15
20
25
31
37
43
49
55
60
14.0
17.0
18.5
22.0
26.0
28.0
32.0
36.0
38.5
Neptune innovative technology is solving a wide var-
iety of problems in water and wastewater treatment.
A nearby Neptune representative has answers.
•All Models: Height-10 feet; Width-10 feet
nepfune
FLOCj
INCORPORATED

WATER AND WASTE WATER TREATMENT DIVISION OF
NEPTUNE METER COMPANY
P.O.BOX 612 • 1965 AIRPORT ROAD • CORVALLIS, OREGON 97330
-------
MicroFLOG filters at Lake Tahoe. California.
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nepturfE
FLOQ
INCORPORATED
NEPTUNE MicroFLOC INCORPORATED

A Subsidiary of Neptune Meter Company
-------
The Solution to Pollution... DesSre
Plus
Dollars
Archie H. Rice, president of Neptune MicroFLOC,
Inc., in the company's Corvallis research and de-
velopment laboratories.
In a talk before the 1966 annual
meeting of the National Reclamation
Association, Mr. Rice said:
"The equation for the solution to pol-
lution is not dilution; it is desire plus
dollars .. . Pollution abatement is no
longer an engineering problem; it is
no longer a scientific problem; and it
is not a legal problem. It is a problem
of politics and economics. If the pub-
lic will spend the money to do the
job, few if any problems cannot be
solved.
"During the past few years major
changes in the pollution abatement
program have resulted from a recog-
nition on the part of the public that
the United States economy can
afford to solve the pollution prob-
lem . . . The money and basic tech-
nology are available to solve the wa-
ter pollution problem."
Mr. Rice speaks from a background
of more than 25 years' experience in
the fields of water and waste treat-
ment—as a sanitary engineer in the
Corps of Engineers, as an assistant
state sanitary engineer, and as an
engineer specializing in the design
of water and waste treatment equip-
ment. He is the 1966 recipient of a
George Warren Fuller Memorial
Award from the American Water
Works Association.
-------
Neptune fViicroFLOC Innovations Contribute
to Advanced Waste Treatment Technology
Application of scientific theory to the development of
practical processes has resulted in several contribu-
tions by Neptune MicroFLOC to basic technology of
advanced treatment of domestic wastes and industrial
effluents. Innovations in areas of solids separation, fil-
tration and process control have been made and dem-
onstrated under practical operating conditions. New
equipment has been developed utilizing these tech-
nological advances.
Efficient Solids Separation in Less
Than 10 Minutes
Several years of Neptune MicroFLOC research and de-
velopment work have resulted in a unique, proven appli-
cation of basic settling theory. Excellent sedimentation
is achieved with less than 10 minutes detention time,
compared with several hours required in normal settling
basins.
The compact solids separation device is packed with
long, shallow tubes. The flow is passed lengthwise
through these tubes, each acting as a shallow settling
device. Settleable material is deposited on the bottom
of each tube and the clarified effluent is continuously
discharged. This tube settler is inclined upward in the
direction of flow to provide for gravity drainage of the
solids. Settling particles need fall only a fraction of an
inch in the tubes rather than many feet required in large
settling basins.
This settling device is in operation in several Neptune
" "icroFLOC waste and water treatment facilities in North
.nd South America, and is providing excellent results
while saving space and capital costs.
This photograph demonstrates how the tubes progressively fill
with floe. The bottom tube is almost full and ready for back-
flushing. The other tubes were placed in service at later inter-
vals to show the progressive advance of the "rolling front" of
sludge deposits.
High-rate Filtration of
Sewage Effluent
Another innovation in advanced waste treatment is
high-rate filtration. MicroFLOC mixed media filter beds
are graded from specially selected coarse media at the
top to very fine media at the bottom. This system in
Affect provides decreasing void sizes in the direction
flow and results in exceptional stability, high filtra-
Tion efficiency and ability to store large quantities of
material between backwashes.
Use of coarse material avoids plugging at the filter sur-
face, a common problem in attempts to apply sand filters
to waste treatment. Similarly, the top-to-bottom grada-
tion enables much finer filter material to be used. Media
as fine as 0.15 mm can be used in these high-rate filters.
MicroFLOC mixed media filters are producing filtrate of
high clarity from secondary sewage effluent, operating
at 5 gpm per square foot.
Automatic Controls Improve
Efficiency, Reduce Costs
MicroFLOC has extensive experience in the develop-
ment and manufacture of automatic control systems to
minimize process malfunctions due to errors or inat-
tention, and to reduce operating costs. Automatic Micro-
FLOC water and waste treatment plants utilizing these
control systems are giving excellent results.
New Approaches to

Industrial Effluent

Treatment Problems

MieroFLOC research and development people
are constantly working with industry to examine
new approaches to industrial effluent treatment
problems. Some of the pilot studies made to ex-
amine feasibility of industrial effluent treatment
include the following:
Separation of cereal grains from hexane stream.
Tertiary treatment of meat packing effluent.
Treatment of process waste waters from elec-
tronics manufacturing.
Treatment of effluent from preservative process-
ing of piling.
Treatment of plywood mill (glue) effluent.
Treatment of wastes from hydraulic gravel
classification.
Treatment of milk processing effluent.
Treatment of steel mill effluent.
Tertiary treatment of combined municipal-
cannery wastes.
Treatment of metal plating effluent.
Treatment of effluent from gypsum wall board
manufacturing.
Soft drink rinse water reclamation.
Reclamation of laundry waste water.
Clarification of flue gas scrubber stream.
-------
Degree of Treatment Can Be Tailored
To Fit Effluent Quality Required For
Pollution Control or Reuse
Increasing concern over pollution of the nation's
rivers and lakes is resulting in higher standards of
water quality at national, regional and state levels.
The traditional approach to waste disposal has been
to provide minimum treatment and depend on the
natural purification capacity of the receiving stream
to do the rest of the job. This use of waterways for
waste disposal is in head-on conflict with the growing
demands of an affluent society for recreational uses
and for preservation of scenic values of our waters.
As a result, the trend now is for subjecting waste
water to higher degrees of treatment, thereby mini-
mizing dependence on natural processes. Conven-
tional sewage treatment processes do not remove
many waste water constituents which are of increas-
ing concern. For example, sewage which has been
treated by conventional means still contains ma-
terial which will stimulate growths of algae in the
receiving body of water. These algal growths can
fere with recreation and downstream use.
authorities agree that the time is near when
the degree of waste water treatment required in many
areas will be so costly that cities and industry cannot
afford the luxury of discarding water after only one
use. In many areas of the world, it is only a matter
of time before serious consideration must be given to
direct reclamation and reuse of waste water to sup-
plement inadequate potable supplies. Already, com-
plete utilization of available potable water supplies
has forced one South African city to the direct
potable use of reclaimed waste water. Within the
United States, reclaimed waste waters are being
used for irrigation, industrial use, groundwater re-
charge, and recreational lakes. However, reclaimed
wastewater is still a generally untapped water re-
source which offers an economical solution to many
water problems.
Technology and equipment now are available to pro-
vide the degree of treatment of waste water neces-
sary to produce any quality of reclaimed finished
water required. The table below shows some ex-
amples of how effluent quality can be tailored to
meet requirements. Reclaimed water of high clarity
and suitable for many industrial purposes can be pro-
duced with simple mixed-media filtration. Chemical
coagulation, filtration and adsorption on activated
carbon can be employed for higher quality effluent,
with removal of phosphates, color and odor.
Qualities of Effluent by Various Processes
TYPICAL EFFLUENT QUALITY

Simple Mixed-Media
Filtration of
Activated Sludge
Effluent
plus Activated
Carbon
Coagulation and
Mixed-Media
^^iltration of
^Aecondary Effluent
plus Activated
Carbon
SUSPENDED
SOLIDS
(mg/l)

20 to 60
1 to 15

TURBIDITY
(mg/l)

0.1 to 1.0
0.1 to 1.0

0.1 to 1.0
0.1 to 1.0
-------
t
Provides 99% Overall
BOD Reduction for Only 10% Increase
in Operating Cost
Operating plants demonstrate that excellent re-
sults can be achieved in simple mixed-media filtra-
tion (no chemicals used) of extended aeration
effluents. Operating at filter rates of 5 gpm per
square foot, overall reductions of 99 percent of
the raw sewage BOD and 98 percent of the raw
sewage suspended solids are provided by simple
mixed-media filtration of extended aeration
effluent. The unique Recla-Mate process produces
filtrate of high clarity even during severe upsets
of the extended aeration plant.
Skid-mounted equipment (Recla-Mate, Series SP),
factory assembled and tested, is available for pro-
viding this degree of treatment for smaller pack-
age plants. The same technology is applicable to
large municipal and industrial plants using field
erected equipment.

Recla-Mate unit is achieving excellent results with
extended aeration effluent at U.S. Forest Service Job
Corps Center at Camp Angell, Oregon.
--- ------ ~
ate SWB Achieves High Degrees of
Turbidity and Nutrient Removal
The use of Recla-Mate SWB with coagulants pro-
vides a means of reclaiming water suitable for
many uses. It is a means of preparing secondary
effluents for activated carbon treatment and de-
mineralization. Efficient coagulation and filtra-
tion of secondary effluent produces a final effluent
with suspended solids and BOD of less than 1
part per million.
Phosphates can be reduced to less than 1 part per
million by using sufficient coagulant. Soluble
organic compounds which contribute to the color
of the filtered effluent can be effectively removed
by adsorption on activated carbon.
Factory assembled and tested Recla-Mate is avail-
able to provide flocculation, sedimentation and
mixed-media filtration up to 140,000 gpd in a
single compact unit. Such a unit is in use with
MicroFLOC ion exchange and activated carbon
[units at Ely, Minnesota.
The Federal Water Pollution Control Administration
recently installed a 20,000 gpd unit at Ely, Minnesota.
It is similar to the 140,000 gpd unit shown.
-------
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:oagulated secondary effluent is filtered on MicroFLOC
lixed-media filters in waste water reclamation plant at
ake Tahoe, California.
MicroFLOC monitoring and control systems provide auto-
matic operation of advanced waste water treatment plants
to Large Automatic Plants
'unicipal, Industrial Use
2.5 MGD water reclamation plant using a pat-
nted MicroFLOC advanced waste water treat-
ment process is in operation at Lake Tahoe, Cali-
fornia. Coagulated secondary effluent is filtered
by MicroFLOC mixed-media. At the Tahoe plant,
filtered effluent has a BOD of less than 1 part per
million, a phosphate content of 0.1 to 1.0 parts per
million, a color of 10 to 30 units, a turbidity of 0.1
to 1.0, a coliform content of less than 2.1/100 ml
following chlorination, and contains no detectable
virus.
This high clarity filtered efflluent then receives
treatment on granular activated carbon. The
carbon columns produce a colorless, odorless
effluent, free of virus and coliform bacteria. Spent
carbon is dewatered and thermally regenerated at
the Tahoe plant.
Cost of regenerated carbon averages about one-
sixth the cost of virgin carbon. Coagulant is re-
covered and reused to further reduce operating
costs.
Additional MicroFLOC filters are being installed at
the Tahoe plant to bring capacity up to 7.5 MGD.
At the same time one more degree of treatment
will be provided with the addition of a stripping
tower to remove 95 per cent of the ammonia nitro-
gen. Use of lime as the coagulant raises the pH to
a favorable range for ammonia stripping at no ad-
ditional chemical costs.
Costs Range from $10 to

$150 per Million Gallons

Water reclamation is an economically
available, dependable and easily ob-
tainable water resource as well as a
positive means of pollution control. The
degree of treatment can be tailored to
specific effluent quality requirements.
Costs are proportionate to the degree
of treatment. For a 10 MGD plant, costs
(including capital, operating, mainte-
nance costs) will range from $10 per
million gallons for plain filtration of sec-
ondary effluent on mixed-media filters,
to $150 per million gallons for chemi-
cal coagulation, sedimentation, filtra-
tion, activated carbon and ammonia
stripping.
-------
Advanced Waste Treatment Technology
The leadership in technology and equipment for
advanced treatment of domestic waste and in-
dustrial effluent which Neptune MicroFLOC has
acquired reflects the capabilities of the company's
staff of process specialists. They are "state of the
art" men who have made original contributions to
the field and are responsible for many of the de-
velopments in waste water reclamation. The proc-
ess experts are supported by a large staff of ex-
perienced mechanical, chemical and electrical
designers.
Walter R. Conley
Director of Research and
Technical Services. A chem-
ical engineer who has pio-
neered and developed many
of today's advanced water
treatment concepts.
Gordon L. Gulp
Research Manager, B.S ,
Civil Engineering, M S., San-
itary Engineering; author of
many pubiished papers on
waste water reclamation; has
extensive experience in
waste water reclamation re-
search and plant scale ap-
plication of advanced treat-
ment processes
Sigurd P. Hansen
Research Engineer, B S ,
Civil Engineering, M. S., San-
itary Engineering; experi-
enced in advanced treatment
of industrial and municipal
wastes, author of several
published papers.
John R. Stukenberg
Research Engineer, B.S.,
Civil Engineering, M.S ,PhD ,
Sanitary "Engineering; spe-
cializing in biological and
advanced treatment of in-
dustrial and municipal
wastes
-------
Hansen, S. P., and Gulp, G. L, "How to Clean Waste-
water for Reuse." American City, (June, 1967).

Conley, W. R., and Evers, R. H., "Coagulation Con-
trol." Presented at 1967 AWWA Conference, Atlantic
City, N.J. (June, 1967).

Gulp, G. L., and Hansen, S.P., "Reclamation of Waste
Water for Reuse." Accepted for the International
Conference on Water for Peace, Washington, D.C..
May, 1967.

Slechta, A. F., and Gulp, G. L., "Water Reclamation
Studies at the South Tahoe Public Utility District."
Water Pollution Control Federation Journal, (May,
1967).

Gulp, G. L., and Hansen, S.P., "Extended Aeration
Effluent Polishing by Mixed-Media Filtration." Wa-
fer and Sewage Works Vol. 114, pp. 46-51 (February,
>967).

Miehe, F. J., "High-rate Filtration of Process Water."
Pulp and Paper Magazine of Canada, p. 90 (Jan.
1967).

Slechta, A. F., and Gulp, G. L., "Phosphorus and Nitro-
gen Removal at the South Tahoe P.U.D. Water Recla-
mation Plant." Presented at 39th Annual Conference
of the Water Pollution Control Federation, Kansas
City, Missouri (September 29, 1966).
Gulp, G. L., and Slechta. A. F.. "Plant Scale Reactiva-
tion and Reuse of Carbon in Waste Water Reclama-
tion." Water and Sewage Works Vol. 113, pp. 425-
431 (November. 1966).

Evers, R. H., "Mixed-Media Filtration." Presented at
Fifth Annual Sanitary and Water Resources Confer-
ence, Vanderbilt University, (June, 1966).

Stukenberg, J., "Water Pollution and Biological
Treatment." Kansas Engineer, p. 14 (April, 1966).

Gulp, G. L., and Slechta, A. F., "Tertiary Treatment
Practice Studies of Carbon Adsorption, Coagulant
Recovery, and Nutrient Removal at Lake Tahoe."
Presented at 38th Annual Conference of the Cali-
fornia Water Pollution Control Association, Monterey,
California (April 28, 1966).

Gulp, G. L., and Gulp, R. L., "Reclamation of Waste
Water at Lake Tahoe." Public Works (February,
1966).

Gulp, G. L., and Slechta, A. F., "Nitrogen Removal
from Waste Effluents." Public Works (February, 1966).

Conley, W. R., "Integration of the Clarification Proc-
ess." Journal American Water Works Association,
Vol. 57, p. 1333-1345 (1965).

Rice, A. H. and Conley, W. R., "The MicroFLOC
Process in Water Treatment." Jappi, Vol. 47, p. 167A-
170A, (January, 1964).
For more information on advanced waste treatment equipment write:
nepaune
FLOQ
INCORPORATED
NEPTUNE MicroFLOC INCORPORATED
P.O. BOX 612 • 1965 AIRPORT ROAD • CORVALLIS, OREGON 97330
A Subsidiary of Neptune Meter Company
-------
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SP
For Existing Installations
Upgrades Existing Package Plants
to Tertiary Quality Effluent
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A Completely Self-
Contained Unit
Treats Raw Sewage to
Tertiary Quality
Effluent
98% Solids Removal
99% BOD Removal
Positive Control of Effluent
. Quality
Automatic Operation
SWB
Phosphate Removal
for Existing Plants or
New Installations
Phosphate concentrations
reduced to less than 0.5 mg/L
WATER AND WASTEWATER TREATMENT DIVISION OF
FLOG I NEPTUNE METER COMPANY
-------
Recla-Pak — The complete sewage treat-
ment plant. (Tertiary quality from raw
sewage.) Recla-Pak offers an extremely
t and economical sewage treat-
system in one package that pro-
duces effluent quality of 98 to 99% solids
and BOD reduction from raw sewage.
Biological treatment is combined with
efficient tube-type clarification followed
by mixed-media filtration. Recla-Pak's
unique clarification/filtration features
provide positive protection against solids
being discharged to the receiving stream.
This unit satisfies the most demanding
pollution control standards.
Recla-Mate "SP" - Tertiary treatment of
effluent from existing package sewage
treatment plant installations. Designed
to "polish" the effluent from biological
package sewage treatment plants, Recla-
Mate employs tube-type clarification and
mixed-media filtration to give overall
reductions of 98% solids and 99% BOD.
Recla-Mate offers these features: a mini-
mum of maintenance and operator atten-
tion and continuous production of high
quality effluent, even during upsets of
the existing upstream plant. Recla-Mate
was designed specifically to upgrade
existing biological package plants to
meet-Hgid pollution control standards.
i-RS-L-R) =
SEDIWENTATIO
— HORUAL FILTER F
—— AACK1M91 *UJW
Recla-Mate "SWB"—Phosphate reduction
for package sewage treatment plant in-
stallations. Recla-Mate SWB is an auto-
matic package unit which employs coagu-
lation, flocculation, tube-type clarifica-
tion, and high rate, mixed-media filtra-
tion. Recla-Mate SWB makes feasible the
tertiary treatment steps required to meet
those pollution control standards de-
manding high degrees of phosphate re-
moval.
PODfELECTROurTE -

ALUM
SECONDLY EFFLUENT
MECHANICAL
FLOCCU.ATOR
TUBE
SETTLER
MIXEO MEDIA
FILTER
FINISHED
WATER
lecla-Mate and Recla-Pak units are easily transportable
:o the jobsite. Installation typically consists of pad or
>urial site preparation and completion of field-ready pip-
ng and wiring connections. The automatic nature of
hese package tertiary plants means low time, cost, and
ikill demands for operation.
Send for specific application data
1
iliu
nepiune
INCORPORATE
WATER AND WASTEWATER TREATMENT DIVISION OF
NEPTUNE METER COMPANY
P.O. Box 612 • 1965 Airport Road • Corvallis, Oregon 97330
-------
Recla-Pak — The complete sewage treat-
ment plant. (Tertiary quality from raw
sewage.) Recla-Pak offers an extremely
eflfccnt and economical sewage treat-
m^K system in one package that pro-
duces effluent quality of 98 to 99% solids
and BOD reduction from raw sewage.
Biological treatment is combined with
efficient tube-type clarification followed
by mixed-media filtration. Recla-Pak's
unique clarification/filtration features
provide positive protection against solids
being discharged to the receiving stream.
This unit satisfies the most demanding
pollution control standards.

Recla-Mate "SP" — Tertiary treatment of
effluent from existing package sewage
treatment plant installations. Designed
to "polish" the effluent from biological
package sewage treatment plants, Recla-
Mate employs tube-type clarification and
mixed-media filtration to give overall
reductions of 98% solids and 99% BOD.
Recla-Mate offers these features: a mini-
mum of maintenance and operator atten-
tion and continuous production of high
quality effluent, even during upsets of
the existing upstream plant. Recla-Mate
was designed specifically to upgrade
existing biological package plants to
mee^-igid pollution control standards.
Recla-Mate "SWB"- Phosphate reduction
for package sewage treatment plant in-
stallations. Recla-Mate SWB is an auto-
matic package unit which employs coagu-
lation, flocculation, tube-type clarifica-
tion, and high rate, mixed-media filtra-
tion. Recla-Mate SWB makes feasible the
tertiary treatment steps required to meet
those pollution control standards de-
manding high degrees of phosphate re-
moval.
FILTEH CVCLE —
SEDIMENTATION -
COLLECTION SUMP
NORMAL FILTER FLOW
— — BACKWASH FLOW
POUrELECTROLYTE

ALUM
FINISHED
WATE9
lecla-Mate and Recla-Pak units are easily transportable
:o the jobsite. Installation typically consists of pad or
jurial site preparation and completion of field-ready pip-
ng and wiring connections. The automatic nature of
iiese package tertiary plants means low time, cost, and
skill demands for operation.
Send for specific application data
,1m
nepjune
FLOG
INCORPORATED
>
WATER AND WASTEWATER TREATMENT DIVISION OF
NEPTUNE METER COMPANY
P.O. Box 612 • 1965 Airport Road • Corvallis, Oregon 97330
-------
1Mb -blMUU GUKPUHAMUN
WATER TREATMENT EQUIPMENT
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.. .For Industrial and Municipal Applications
-------
Eimco Reactor-Clarifierru water treatment
unit is a highly versatile machine that combines
flocculation, coagulation, clarification and
positive sludge removal in a single tank. For
municipal or industrial use, these are the most
compact and economical to operate units
available today. They will remove turbidity, algae,
color, iron and other contaminants. They
accomplish lime or lime-soda softening,
magnesium precipitation, brine softening or
clarification and wastewater clarification.
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Solids-Contact Types HRC and HRB . . . use th
proven, highly efficient upflow solids contact
action. Large diameter turbines internally
recirculate large quantities of previously forme
floe or precipitates at low peripheral turbine
speeds. In softening operations, this recirculatic
can be up to 15 times the feed rate with slurry
density up to 5 per cent by weight. Excellent
overflow qualities and dense underflows are
obtained in this simple, stable operation. The
is no unstable sludge blanket to
upset the operation.
Type HRC from 50 to 200 ft. diamet
Type HRB from 10 to 75 ft. diame'
-------
Reactor-Clanfier
treatment units
Type CF — Standard rate 30 to 200 ft. diameter,
center column supported. This is a standard
rate unit which combines vertical paddle
flocculation with clarification. Center column
units in sizes from 30 to 200 ft. diameter are
standard. Recommended for turbid water
clarification, algae and color removal. The
sta^ard unit has a uniform influent
di^Boution system.
Type BFR — Standard rate type up to 70 ft.
diameter, beam supported. The BFR is a
standard rate type that combines slow speed
turbine flocculation with clarification. Beam
supported units only for diameters 20 to 70 ft.
For turbid water clarification and treatment of
industrial wastes where gentle flocculation by
turnover is beneficial.
Bf
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Type CF from 30 to 200 ft. Diameter
Type BFR from 20 to 70 ft. Diameter
-------
Partial list o
Typical industrial users of Eimco
Reactor-Clarifier treatment units.
Upper left
The Southern Nevada Power Company's Sunrise
Station Effluent Treatment Plant includes a
60-ft. diameter Reactor-Clarifier for solids
contact cold lime treatment to remove phosphate
from sewage treatment plant effluent prior to
cooling use. The sewage effluent contains
from 15 to 35 ppm as Ortho-PO,, and less than
1 ppm after treatment. — Steams-Roger
Corp. engineers

Left center
U. S. Steel Corporation's plant near Provo, Utah
utilizes Reactor-Clarifier treatment units for
mill scale water treatment. Special skimming
devices are used to remove oil.

Lower left
Two 55-ft. diameter high rate Reactor-Clarifier
Kat Kaiser Steel Corporation, Fontana,
rnia. Six Reactor-Clarifier units are used at
lant for treating various types of steel
mill waste water treatment and for
water reuse. — Kaiser Engineers

Upper right
Process water for the Allied Paper Company
kraft mill at Jackson, Alabama is treated in a
150-ft. diameter by 32-ft. sidewail depth
Reactor-Clarifier treatment unit High color and
turbidity removal of river water is accomplished
at rates up to 26 mgd. In addition to clarification,
the unit provides storage of 1 million
gallons of water. The launders are
submerged eight feet below surface. — Eastern
Engineering Company

Lower right
A high rate Reactor-Clarifier treatment unit at
Northwest Paper Company's mill at Cloquet,
Minnesota, removes turbidity from 30 to
40 mgd of river water.
V .
-------
dustnal users of Eimco Reactor-Clanfier treatment units
'' /*'
-------
Partial list
Municipal users of Eimco
Reactor-Clarifier treatment units include
both large and small plants.
Upper lett
The residents of Merida, Yucatan in Mexico now
have a highly efficient treatment plant. Two
90-ft. diameter Eimco Reactor-Clarifier treatment
units form the basis for the high rate softening
plant. — Charles S. McCandless Co.,
engineers

Lower left
At Titusville, Florida, the high rate Reactor-
Clarifier treatment unit, 50-ft. diameter, is used
for turbidity removal and softening. The heavy
duty construction of the unit makes it possible
to handle the heavy sludge which results from
softening. Plant capacity is 6 mgd. —
Black, Crow arid Eidsness, Inc., engineers.

Upper right
resort city of Aspen, Colorado has a 4 mgd
nt plant which uses a type CF
r-Clarifier treatment unit,
75-ft. diameter. — Dale H. flea, engineers

Center right
Four high rate Reactor-Clarifier water treatment
units are installed at the Rinconada Water
Treatment Plant of the Santa Clara County,
California, Flood Control and Water
District. — Kennedy Engineers

Lower right
At State University of Iowa, two Reactor-Clarifier
treatment units are used in the plant for both
the city and university. Students use the plant
for laboratory and research work. — Stanley
Engineering Company
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lunicipal users of Eimco Reactor-Clanfler treatment units
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nunicipal users of Eimco Reactor-Clanfier treatment units
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Upper photo
Water treatment plant for the fine paper company of P. H. Glatfelter
Co., Spring Grove, Pennsylvania, includes this 105-ft. diameter
Reactor-Clarifier treatment unit, type HRC. -— J. E. S/mne Co., engineers.
The San Geronimo plant of Marin Municipal Water District near
San Bj^el, California uses this 125-ft. diameter Reactor-Clarifier unit in
the ^•nent process. — Kennedy Engineers.
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list of users of Eimco Reactor-Clanfler treatment units
User

Kaiser Steel Corporation
Fontana, California
No.
Units

2
1
1
2
1
> 1
Kaiser Aluminum and Chemical
Corporation, Mea'd, Washington
U.S. Department of Interior 1
Fairbanks, Alaska
North Marin County Water Dist. 1
Novato, California
U.S. Naval Base 1
Guam, Mariana Islands
Missouri Water Company 1
Independence, Missouri
PASA Petrochemical Complex 1
Rosario, Argentina
Ham Tan, Vietnam 1
Kontum, Vietnam 1
Tuy-Hoa, Vietnam 1
Phan-Rang, Vietnam 1
Khangh-Hung, Vietnam 1
Atlantic Cement Company, Inc. 1
Ravena, New York
American Oil Company 1
Sugar Creek, Missouri
Novamont Corporation 1
Neal, West Virginia
Northern Illinois Water Corp. 4
East Side Plant
Champaign, Illinois
Southern Nevada Power Co. 1
Clark Station
Las Vegas, Nevada
Western Electric Company 1
Millard, Nebraska
Western Electric Company 1
Lee's Summit, Missouri
West End Chemical Company 1
Green River, Wyoming
Albemarle, North Carolina 2
U.S. Steel Corporation 2
Columbia-Geneva Division 2
Geneva, Utah 1
Marin Municipal Water District 1
Bon Tempe Plant
San Rafael, California
Goodyear Tire & Rubber Co. 1
Sao Paulo, Brazil
Union Minere du Haut Katanga 1
Belgian Congo, Africa
Anaconda Aluminum Co. 1
Columbia Falls, Montana
Gresik Cement Corporation 1
Surabaia, East Java, Indonesia
Tata Iron and Steel Co. Ltd. 3
Jamshedpur, India
H. K. Porter Co. 1
Pascagoola, Mississippi
Wichita, Kansas 1
U.S. Steel Corporation 2
Columbia-Geneva Division
Pittsburg, California
Campbell Soup Co. 1
Sacramento, California
Northwest Paper Company 1
Cloquet, Minnesota
Dia.
in
Feet

90
115
75
55
50
125

18
18
21
30
35
60

75
135
85
90
125

150
No.
User Units

Dayton, Ohio 4
Anaconda Aluminum Co. 1
Columbia Falls, Montana
Western Electric Co., Inc. 1
Bell Telephone Laboratories
Holmdel, New Jersey
S.D. Warren Company 1
Muskegon, Michigan
Jackson County Port Authority 2
Pascagoula, Mississippi
Independence, Kansas 1
General Motors Corp. 1
Guide Lamp Division 1
Anderson, Indiana
Twin City Water Dept. 2
Uhrichsville & Dennison, Ohio
Vicksburg, Mississippi 2
Allied Chemical Corp. 1
General Chemical Div.
Painesville, Ohio
Jones & Laughlin Steel Corp. 1
Cleveland, Ohio
Union Carbide Corp. 1
Marietta, Ohio
Republic Steel Corp. 1
Chicago, Illinois
U. S. Steel Corp. 1
Dravosburg, Pennsylvania
Caterpillar Tractor Co. 2
Mapleton, Illinois
Jones & Laughlin Steel Corp. 2
Hennepin, Illinois 2
U. S. Steel Corp. 1
Gary Sheet & Tin Works
Gary, Indiana
Owens-Illinois Forest Products Div. 1
Orange, Texas
Union Miniere du Hautkatanga 2
Belgian Congo. Africa
Alabama Kraft Co. 1
Mahrt, Alabama
Crucible Steel Co. of America 1
Midland, Pa.
St. Regis Paper Co. 2
Monticello, Miss.
Consolidated Aluminum Corp. 1
New Johnsonville, Tennessee
Western Electric Company, Inc. 1
Indianapolis, Indiana
Sylvania Electric Company 1
Warren, Pennsylvania
Continental Can Company 1
Augusta, Georgia
Kigali, Rwanda, Africa 1
New Orleans, Louisiana 1
Algiers Water Purification Plant
Olin Mathieson Chemical Corp. 1
West Monroe, Louisiana
Inland Steel Company 2
Hot Strip Tinning Mill
Indiana Harbor, Indiana
Anaconda Aluminum Company 1
Columbia Falls (Conkelley), Mont.
North American Aviation, Inc. 1
Columbus, Ohio
Union Carbide Nuclear Company 1
Paducah, Kentucky
Dia
in
Feet

94
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Thetimco SVG™ Filter is a simplified, automatic
gravity filter with a self-contained backwashing
system designed to provide efficient and
economical operation for both municipal and
industrial plants. The filters can be installed in
multiples to meet capacity requirements.

The SVG filter has these major advantages:
. . . Completely automatic in operation,
... All piping, pumps and control and
regulating valves required for a conventional
separate backwash system are eliminated.
... No raw water is wasted during the
backwash cycle.
. . . Complete control — both hand and fully
automatic — is provided.

A single three-way butterfly-type valve provides
complete hydraulic control. The valve can be
operated either with an electric, hydraulic or
pneumatic actuator. While filtering, the valve
opens the inlet line and closes the waste line.
During backwashing the valve reverses, closes the
inlet line and opens the waste line. The backwash
cycle is automatically initiated by an adjustable
loss-of-head switch in the inlet line (normally set
at 5 ft. head loss), or manually by pushbutton. The
backwash cycle terminates when a low level
praj^ jn the storage compartment is actuated.
Tl^P^ackwash rate is adjustable and varies from
approximately 24 gpm/sq. ft. to 10 gpm/sq. ft. with
an average of 15 gpm/sq. ft. The backwash period
lasts for approximately 41/2 minutes. The complete
control package includes a selector switch which
permits manual pushbutton control and control
over-ride as well as the normal automatic control.
Simplicity of the unit reduces installation costs
and space requirements are significantly minimized.

S VG-M
To meet some local and state public health
requirements and air space or double wall is
needed between filtered and unfiltered water
passages and compartments. The SVG-M filter
fulfills this requirement by separating the backwash
water storage and filtering compartments with an
air section and by placing their connecting pipes
outside the filtering compartment.
Both types of filters use Eimco FlexKleen™
distributors. For additional information see page 14.
J _!..-_--
ft.
Upper photo
At McGuire Air Force Base near Wrightstown, N. J., the water treatment
plant includes 9 S V G-M filters. — Geffer-Green Associates, engineers'.

Lower left
Six Eimco S V G-M filters at the municipal water treatment plant at
Galesburg, Illinois. The filters handle 8 mgd removing precipitated
iron. — Plant engineering by Galesburg City Engineering Department.

Lower right
Two SVG filters polish the water for boiler feed of the Colorado-Ute
Electric Association, Inc., steam generating plant at Hayden,
Colorado. — Stanley Engineering Company.
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SVG Filters
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The Eimco Flocsillator™ horizontal oscillating flocculating
mechanism provides a highly efficient way to gently
mix and agitate water for developing floe. All wearing
components are above water assuring long life. The
flocculating mechanism is particularly suitable for large
or small municipal plants where horizontal-flow
flocculating is desirable. These mechanisms also can
be installed in existing basins to provide flocculation at
lower operating costs with a minimum change to existing
structures. The paddles of the Flocsillator mechanism
travel through approximately 80 per cent of the tank
volume and influence 100 per cent of the volume. The
action of the lower vertical arms effectively prevents
precipitation in the corners of the tank, although there is
no high-velocity turbulence to destroy previously formed
floe. The Eimco Flocsillator mechanism has many
mechanical advantages not found in any other type of
flocculator. The drive shaft and bearings are located
entirely out of water and are easily accessible for
servicing. There are no dry wells, submerged bearings or
stuffing boxes to construct or maintain. Mechanisms
can be custom designed to fit other basin configurations.
Standard Flocsillator mechanisms are available in sizes
designed for operation in basins 20 ft. wide by 12 ft.
deep and from 16 to 96 ft. or more in length.

«ico horizontal shaft (Type HP or Type HT) flocculators
heavy duty units designed for large plants. The
iable speed drive unit can be mounted on the roof
of or inside a dry well, driving the paddle shaft by
means of a roller chain. Two or more flocculators
can be operated from one drive unit by sprocket and
chain connections in the dry well. Heavy duty construction
throughout for years and years of trouble-free service.
The HT unit is applicable to high energy application.

have high circulation
capacity using a turbine drive to circulate up to 25 times
the initial feed with low power consumption. The blade
arrangement is used to vary the flow pattern. Tank sizes
up to 38 ft. diameter. No submerged bearings. Applicable
to high energy applications.

Vertical paddle flocculators (Type VP) are available in
sizes 6 to 50 ft. No dry pits are required. Motor sizes from
fractional to 5 hp depending on mechanism diameter
and basin depth. Can be installed in series in a single
rectangular basin with a surface influent weir and a
submerged effluent weir to provide the most
efficient flocculation.

Flash Mixers (Type VT) are available in 1 to 20 hp size
vertical turbine design for blending coagulants with raw
water and chemical mixing. Also used for neutralization
and general purpose mixing.

Upper photo
Eimco Flocsillator horizontal oscillating flocculating mechanism at the
400 mgd F. E. Weymouth Memorial Softening and Filtration Plant,
Metropolitan Water District of Southern California, LaVerne.
Lower left
One of the sets of horizontal paddle flocculators at the Miramar Water
Filtration Plant, San Diego, California. — James M. Montgomery
engineers.
Lower right
Eimco Flocsillator
Type HT
DHL
Type HP
n~L~a
TJ
Type VP
Slit™
Type VTR
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Flocculators
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^ Air-Water Wash
T)ual Media Filters Underdrains
Clanfier
Dual media double gravity filters which utilize Eimco
FlexKleen™ nozzles and the Eimco Air Wash System have
«'eral major advantages for polishing treated water. The
xKleen nozzles, which are manufactured of non-
rodible plastic with flexible stainless steel screens, are
threaded into precast concrete blocks to form a filter
bottom. In dual media applications they are covered with
a layer of sand and a layer of anthracite. The filter
underdrain blocks are 24 in. square, 3 in. thick. They can
be supported by circular or square piers on 24 in.
centers or on longitudinal beams placed across the filter
floor. Threaded plastic inserts cast into the blocks
receive the threaded distributors. In the airwash system,
the distributors are supplied with plastic tubes which
extend below the blocks. The use of air with the backwash
provides an especially vigorous wash, with thorough
scrubbing of the filter medium. The amount of wash water
required is reduced by as much as one half. The agitator
eliminates the possibility of "mud balling" tendencies and
requires no surface washers or the additional water
they use. There is no drifting of gravel or breakthrough
caused by surges in backwash. The FlexKleen nozzle
is highly resistant to clogging.
Clarifiers — For pre-sedimentatic
of silt and sand or for settling
after flocculation. Beam supporte
units are available for tanks 20
to 45 ft. diameter; center column
and traction types for tanks 30
to 325 ft. diameter. Types availabl
for rounded corner square tanks
with cross-flow arrangement, sid/
feed or center siphon feed with
conventional overflow. Driveheac
are of efficient design with
quality construction throughout
using high grade materials.
Adequate drive gear to machine
size ratio equals trouble-free,
low maintenance operation.
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Softening Sludge
Dewatermg
Package Plants
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Eimco Package Plants — Available for
gravity operation using SVG automatic
sand filters. Eimco offers a complete line
of these pre-designed water plants for
municipal or industrial use and for boiler
feed. Plants are available in sizes from
50 to 1,000 gpm as standard and can be
custom designed for larger volumes on
request. Many operating efficiencies
contribute to lower operating costs.
Automatic units are fully dependable.
Eimco offers a package combination to
thicken and dewater the sludge which
results from softening. Sludges can be
dewatered to approximately 65 per cent by
weight of dry solids on an EimcoBelt®
continuous belt filter. The blinding
characteristic of the softening sludge
presents no filtering problem for an
EimcoBelt filter, which operates at all times
with a washed, clean medium. Simplified
EdgeTrack™ belt filter operates with
minimum of operator attention and provides
long belt life. The Eimco thickener used in
conjunction with the EimcoBelt filter can
be equipped with an automatic raking
device to prevent damage to raking arms
by the heavy sludge.
-------
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The Elm Fork Water Treatment Plant serving the City of Dallas, Texas, has 2 Eimco

Type 2C2 clarifiers, 160-ft, in square basins. — Forrest and Cotton, engineers.
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BY: W. H. JOHNSON/THE EIMCO CORPORATION/SAN MATED. CALIFORNI
Treatment of Se\vage Plant
Effluent for Industrial Reuse
-------
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Photo No. 1. The Clark County Sewage Treatment Plant necr Las
Vegas, Nevada. Part of the effluent from this plant is further treated
ond used for cooling water at the Nevada Power Company's 2CO
megawatt Clark Station about ijj miles away (see arrow).
-------
Treatment of Sewage Plant
Effluent for Industrial Reuse

BY: W. H. JOHNSON/THE EIMCO CORPORATION/SAN MATED, CALIFORNIA
Of all the sources of water available to industry,
rfche one most reliable in all seasons and the only
'one that can be considered as increasing in quant-
ity, and improving in its quality is sewage plant
effluent.
The practicability of using this effluent is now
firmly established, with over a half dozen industrial
Rlants in the southwest having used it for sufficient-
j long periods to permit a description of how it
should be further treated before it can be safely
and efficiently reused.
This water source, when properly treated, should
be satisfactory for most cooling purposes and, inas-
much as 75% of all industrially used water is for
cooling, this paper will be primarily directed toward
discussion of that usage. In particular, it will dis-
cuss the special and extra treatment required for
the effluent.
The Eimco Corporation is indebted to the per-
sonnel at the Las Vegas based Nevada Power Com-
pany's Clark and Sunrise Stations and to the Nalco
Chemical Company for the generous assistance
given in providing much of the data that are used
herein. The experience gained during the 3 years of
operation of the sewage effluent treatment facilities
at the 200 megawatt Clark Station followed by the
recent start-up of the newer facilities at the 90
megawatt Sunrise Station, provides much of the
data used in this paper. Some comparisons are also
included here between other industrial effluent
sers, particularly those in Amarillo, The Texas
iompany and the Southwestern Public Service
Company, both of whom have provided operating
data for this discussion.
Quality is the first consideration in the use of
effluent from a domestic sewage treatment plant.
Effluents can differ greatly. There are maximum
organic content limitations that must be met before
it can be called even a partially reclaimed water
suitable for further treatment as water.
Biological treatment of the sewage is certainly
necessary. Simple primary treatment by gravity
settling is not adequate. The effluent BOD (Bio-
chemical Oxygen Demand) should not average
over 25 ppm and preferably should be less. Suspend-
ed solids should be under 25 ppm and preferably as
low as possible. Other constituents, particularly
dissolved minerals and synthetic detergents, are
not usually influenced by the sewage treatment pro-
cess and must be taken as they come.
The need for further, treatment of the effluent,
or reclaimed water as it may be called, will vary
with the use to which it is put. It is possible that
it may be utilized after only additional settling
such as for the once through roll cooling and
quenching operations at Bethlehem Steel's Spar-
row Point Plant near Baltimore. On the other hand,
a very complete treatment may be required such as
at Texaco's Amarillo Refinery, where a portion of
the reclaimed water is hot lime softened, filtered
and further ion exchange softened for use as feed
water for low pressure boilers. But since it is re-
cycled cooling water usage that interests us most,
it is the required treatment for the protection of
the cooling surfaces and towers that we will review
in detail.
It is for the following purposes that a reclaimed
water must be further treated so that it may be
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Photo No. 2. The Nivada Power Company's Clark Station Effluent
Treatment Facilities. In the foreground is a 57' diameter cold
Lime Treatment Reactor-Clarifier. The chute and hopper over the
top of the control building stores unslaked lime.
used with confidence in a recirculating cooling
«stem:
1. Remove orthophosphates.
Orthophosphates (along with foam causing
Alkyl Benzene Sulfonate) come from the
synthetic detergents found in increasing
quantities in domestic sewage. Only small
reductions occur in the conventional sewage
treatment processes; therefore, special steps
by lime treatment must be taken to eliminate
it. Failure to remove this phosphate would
result in scaling.
2. Reduce the remaining suspended solids.
The suspended solids are principally organic
and need to be reduced to prevent organic
fouling and to keep down chemical dosages.
This clarification step and the phosphate
removal can be accomplished simultaneously.
3. Kill all bacteria and maintain the residual or-
ganic matter sterile. Sterilization is particul-
arly important. Effluent leaving the sewage
plant will probably be chlorinated but addi-
tional dosages may be needed to keep the wat-
er under continuous control.
4. Reduce as much as necessary and practical,
hardness, foam, silicates, nutrient matter and
other dissolved solids. These are of secondary
importance, and should create no great pro-
blems but their reduction would be considered
beneficial.
Until 1961 Nevada Power Company's Clark Sta-
tion, used biologically treated sewage plant effluent
Tithout further treatment other than chemical
additives, in the towers. At that time, the ortho-
phosphates averaged about 17 ppm permitting up
to two cycles of concentration. Since 1961 the or-
thophosphates have increased, at times to over 40
ppm, averaging 35 ppm, making their removal
mandatory before the water can be safely used at
all. Even so, this sewage plant effluent is equal or
superior in overall quality to many raw surface or
ground-water sources that are being used for similar
purposes in other parts of the country.
The source of the effluent is the Clark County
Sewage Treatment Plant several miles away (see
Photo No. 1).
In a 1961 enlargement, facilities were const-
ructed at Clark Station (see Photo No. 2) to
treat up to 2500 gpm of effluent to remove phos-
phates and reduce suspended solids. In the spring of
1964 the nearby Sunrise Station was completed.
Included in that installation is a 2000 gpm effluent
treatment facility (see Photo No. 3). Sunrise Sta-
tion is connected to both Clark County and the City
of Las Vegas (see Photo No. 4) Treatment Plant
outlets. Both of the sewage plants use biological
filtratilon for secondary treatment as may be seen
from the photos. Table 1 gives a typical analysis of
the effluent from the City Plant.
CONSTITUENT

Suspended Solids
BOD
Calcium (as CaCO^)

Phosphates (Ortho) as PO4 . .

Chlorine Residual
Temperature (April)
pH
SEWAGE
PLANT
EFFLUENT

18 PPM
20 PPM
120 PPM
35 PPM

0.1 PPM
71° F
7.8
Table I. City of las Vegas Sewage Treatment Plant Typical Effluent
Analysis. This reclaimed water is further treated for phosphate re-
moval and suspended solids reduction and used at Nevada Power
Company's Sunrise Station.
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The treatment at the two Nevada Power Company
plants consists of pre-chlorination followed by cold
jlime softening in a solids contact Reactor-Clarifier
using- large volume, dense solids sludge recircula-
tion. Removing phosphates and suspended matter
by this means has proven to be efficient and econ-
omical, rendering the water quite suitable for cool-
ing use and permitting up to five cycles of concent-
ration. Diagram No. 1 illustrates a typical flow
sheet of the installations.
Chlorine for sterilization is applied to the sewage
plant effluent as it leaves the plant. Additional
chlorine is added at the power stations in sufficient
quantities to maintain a minimum 1.0 ppm resid-
ual. Dosages at the Clark Station presently aver-
age 12 to 15 ppm. For a short period each week
shock dosages are also applied to the towers.
In the cold lime softening process, phosphates
are efficiently removed by adsorption on the pre-
cipitated lime sludge. Phosphate content of less
than 1 ppm has been consistently maintained in the
treated water, and is no longer the controlling fac-
tor in concentration cycles. Calcium and total solids
concentrations now determine the need for blow-
down. Since phosphate removal is by adsorption on
the sludge, large volume recirculation of the densest
sludge gives the best treatment. In the newer Sun-
rise Station facilities the Eimco cold lime treatment
unit is of the type that carries a low bed or reser-
voir of sludge which is continuously and internally
circulated through the incoming feed. In addition,
^external sludge blowdown facilities have been piped
fso that sludge may be either pumped back into the
Reactor-Clarifier or excess sludge sent to the drying
beds.
Suspended solids or turbidity removal has not
been as consistently effective. Organic matter in the
effluent does not coagulate easily and sometimes,
especially if the solids content is high, good clarity
is more difficult to achieve. At clarifier rise rates
of 1.25 gpm/sq. ft. satisfactory phosphate removal
can be achieved but clarity suffers especially if the
sewage effluent contains substantial amounts of
suspended matter. Indications are that the best and
most consistent clarification results are achieved at
rise rates of 0.8 gpm/sq. ft. and a gross detention
period of 2^2 hours or more.
The older Clark Station Reactor-Clarifier, 57'
dia. x 18' deep would normally be rated at 3000
gpm but in order to keep clarity consistently ac-
ceptable it treats an average 2000 gpm flow. The
newer Sunrise Station unit is 60' dia. x 15' deep
and is designed for 2000 gpm.
Failure to maintain a chlorine residual through
the Reactor-Clarifier will produce disastrous re-
sults, with the sludge becoming septic and com-
pletely upsetting clarification.
Many types and varieties of coagulants and aids
have been tried at Las Vegas but none have yet
proven in operation, to give better results than just
lime alone. At this writing no other coagulants or
aids are used. Most of the time effluent clarities
average 5 to 10 ppm, but if incoming suspended
solids get high, the overflow may become less clear.
Hardness reduction has been mystifyingly low,
while lime demand has been higher than theoreti-
cally necessary. Calcium precipitation has been
consistently less than that of magnesium. Table II
illustrates a typical analysis before and after cold
lime treatment. It is generally believed that or-
ganics interfering with calcium precipitation ac-
count for this phenomena. It is probable that the
orthophosphates have some effect too. In tests run
by Malina and Tiyaporn (Ref. Fig. No. 1) on the
CHLORINE
TYPICAL SEWAGE PLANT EFFLUENT
TREATMENT FACILITY TO
RECOVER WATER
FOR COOLING USE
CONTROL BUILDING
f~\ SLUDGE I
' V-s? '. VV
INLET METER
PLAN
FLOW DIAGRAM NO. 1
FLOW SHEET
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Photo No. 3. The Nevada Power Company's Sunrise Station Effluent
Plant includes this 60' diameter solids contact cold lime treatment
Reactor-Clarifier with means for large volume, dense solids internal
recirculation. Treated water is stored in the basin at the rear.
Photo No. 4. Across one of the biological filter* at the City
of Las Vegas, Nevada Sewage Treatment Plant may be seen Nevada
Power Company's 90 megawatt Sunrise Station. A portion of the
effluent from this sewage plant is further treated at the power
station and used for cooling water.
effect of sodium orthophosphate (and ABS) on
hardness removal of a lake water by lime soften-
ing, these results were stated — "The residual
hardness of the lime treated water increased from
92.9 to 136 mg/1 as CaC03 as the original phos-
* ahate content increased from zero to a concentra-
tion of 5.11 mg/1 as P04. At concentrations from 5
to 20 mg/1 of Na2HPO4 initially added to the wat-
er, the hardness of the water after lime treatment
was unchanged and remained at about 136 mg/1
as CaC03". In addition they followed this by
stating, "Lime treatment of the water resulted in
complete removal of the phosphates, as well as the
removal of some of the ABS". Their tests further
indicated that the ABS did not interfere with lime
treatment of the water.
Constituent

Calcium (as CaCO3)

Magnesium (as CaCO3)

Total Hardness
P Alkalinity
MO Alkalinity
Sulphates (as Na2SO4)

Chlorides (as NaCl)
Phosphates (Ortho-PC4)

Silica
Total Solids
PH
Chlorine Residua!
COD (as O2)
BOD
Suspended Solids

Table II. Typical Analysis of Reclaimed Water from Clark County
towage Plant before and after Cold Lime Treatment. Clark Station —
evada Power Company — 1962.

* Reactor-Clarifier is the Eimco so'ids contact cold lime treatment unit
Sewage Plant
Effluent To
Reactor-Clarifier*
PPM
135
165
300
240
0
200
200
14 to 35
20
820
7.0
1
—
20
20
Reartor-Clarifier*
Treated
Water
PPM
115
105
220
95
165
200
200
Less than 1
10
750
10.0
0.3
47
_
5 to 10
Lime dosages as required to obtain a 2P-M value
(two times phenolphthalein alkalinity minus
methyl orange alkalinity) of +20 to +40 have giv-
en best overall results at Las Vegas. An average
dosage of 1.5 Ibs. of chemical lime per 1,000 gallons
of water treated is required. Treated water pH of
10.0 or slightly above are sent directly to the stor-
age reservoir without acid treatment or carbona-
tion except that naturally obtained through contact
with the atmosphere. No scaling has been noted in
the Reactor-Clarifier discharge lines or the reser-
voir. Acid addition of 0.2 Ibs. per 1,000 gallons to
the circulating tower water maintains the pH be-
tween 7.2 and 7.5.
Foaming at Las Vegas has not been a problem
since treatment of the effluent began. Formerly,
when the effluent was used without further treat-
ment, foam patches were pulled up through the
tower fans and blown across the yards. In the upper
portion of Photo No. 5 (taken on the day of plant
start-up in 1961) may be seen the large white foam
areas floating in the water storage reservoir. Within
a few days after stable operation was achieved, this
foam disappeared (see Photo No. 6) and has not
been back since. While no tests were taken to deter-
mine the amount of foam causing ABS removed in
the cold lime treatment, it does appear that foam
is inhibited to a degree. Malina and Tiyaporn's ex-
periments showed a 30 to 60 percent ABS removal
by lime treatment of their lake water. In any case
foaming should become less of a problem as time
goes on since within a few years biodegradable
detergents will be in use and they will more likely
be removed in the sewage treatment process.
Silica in the sewage effluent runs higher than
that of the city water supplies, but its reduction by
20% to 60% in the cold lime treatment takes it
down below its former level. The relatively high
-------
Photo No. 5. Before. Photo taken at start-up time of the Clark
Station effluent treatment facilities in 1961. Note the white foam still
remaining in the storage basin in the background. After a few dayj
of operation, the foam disappeared and has never returned.
(See Photo No. 6) The unit shown is a 57' diameter solids contact
cold lime treatment Reactor-Clarifier.
Photo No. 6. Afler. Clark Station storage basins in 1962 after
effluent treatment facilities had been in operation for some time.
Note the complete absence of foam, slime or algae growth.
magnesium hydroxide precipitation no doubt ac-
counts for this.
Overall operation and results have been quite
satisfactory. The treated water is stored in an open
feservoir without developing slime or algae growths.
Copper sulphate treatment has not been found
necessary as long as chlorine residuals are main-
tained through the clarifier. Tube inspection after
3 years has shown only slight scaling and it has not
been organic. The average number of cycles of con-
centration has been five, with the limit determined
by calcium and total dissolved solids concentra-
tion. Only the usual tower water control chemicals
have been required — acid (for pH), polyphosphat-
es, algicides and periodic shock chlorination.
Experiences with reclaimed water at Amarillo
have been generally similar to those at Las Vegas
but with some variances. The main differences are
these:
Amarillo's Water Reclamation Plant uses the
activated sludge process of sewage treatment fol-
lowed by 3 days storage at the plant. This storage
serves to further oxidize, clarify and equalize the
effluent before it is sent to the two industrial users
— Southwestern Public Service Company's Nichols
Station and the Texaco Refinery. Table III gives a
comparative analysis of Amarillo's City Water, raw
sewage, reclaimed water and treated effluent.
Chlorine is applied in sufficiently heavy doses
at the sewage plant to maintain 1 to 5 ppm re-
sidual in the effluent at the time it reaches the user.
An average of 9 ppm is used to do this.
. Clarity results are similar to those at Las Vegas,
iowever alum has been found to be beneficial when
sed at the rate of 30 ppm. During difficult periods
small amounts of Separan NP10 have also been of
some benefit. But there are times when good coagu-
lation can not be achieved and clarity becomes
poorer. These occasional bad periods are apparently
not of great overall significance.
At the Public Service Plant, pH is reduced im-
mediately after treatment to 9.0 by sulphuric acid,
to prevent scaling in the lines and storage tanks.
A possible reason for a higher scaling tendency
at Amarillo than at Las Vegas may be because they
treat to a higher phenolphtalein alkalinity, aiming
for a 2P-M value of between +50 and +90. Also
there are not as many provisions for recirculation
of dense bottom sludges as at Las Vegas, which
aids in stabilizing the water.
Amarillo
Constituent
Calcium (CaCO3)
Magnesium (CaCO3)
Sodium
Iron
M. Alkalinity
Hardness (CoCO3)
Silicate
Ammonia Nitrogen
Nitrate Nitrogen
Phosphate (PO4)
Chloride
Sulfate
Total Dissolved Solids
Suspended Solids
Biochemical Oxy. Demand
Chlorine Residual
pH
Untreated
Raw
City Water Sewage
39
37
27
0
225
244
56
0
1
0
14
36
356
0
0
PPM
PPM
PPM

0.2
7.5
110
140
—
—
367
250
_
25
0
35
162
—
671
236
275
0
PPM
PPM

7.5
Sewage
Plant
Effluent
110
140
110
0.3
334
250
79
20
2.30
27
83
78
557
11
10
5.0
7.7
PPM
PPM
PPM
PPM
PPM
PPM
PPM
PPM

PPM
PPM
PPM
PPM
PPM
PPM

Cold Lime
Treated
Water
100
60
—
—
270
180
45
—
—
1.0

—
—
5
—
1.0
10.3
PPM
PPM

Table III. City of Amarillo, Texas Comparative Typical Analysis of
City Water, Raw Sewage and Treated Effluent from the City's Water
Reclamation Plant. This Reclaimed Water is further treated and used
by the Texaco Refinery and Southwestern Public Service Company's
Nichols Station to give tho typical results shown in the last column.
-------
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i—- r *
iTiU-
i i
I
Photo No. 7. Clark Station cooling towers using treated sewage
plant effluent average five cycles of concentration. No foaming
problems are experienced.

Two special problems involved in the use of
sewage plant effluent are (1) its residual organic
content and (2) its relatively inconsistent charact-
er. Raw sewage is quite variable in both its quality
and quantity. It varies by the hour, by the day and
even by the month. A secondary sewage treatment
process will tend to even out some of the fluctua-
tionsdth BOD and suspended solids removal rang-
75% to 90% throughout any day, varying
h flow rate and the raw sewage quality.
It will not appreciably affect mineral content, hard-
ness, alkalinity, temperature or pH. While it is rea-
sonable to expect to average less than the maximum
permissible BOD and suspended solids in the ef-
fluent, there will be those fluctuations along with
the other quality variations that may affect the
effluent user's additional treatment steps. This is
one of the important points that must be taken into
account when reclaimed water is being considered.
To overcome these variations, in part at least, an
equalization and storage basin should be provided if
possible. Its function would be to even out the ef-
fluent quality and provide stand-by storage as well.
A basin with a day's capacity or more, with proper
inlet and outlet provisions to prevent short circuit-
ing would help considerably. The benefits of further
settling and oxidation will also improve quality. By
including a means of aerating and mixing a portion
of the storage tank contents additional organic con-
tent reductions could also be obtained.
At Las Vegas there was no such basin for the
County plant. However an approximately one-day
capacity pond is now nearing completion. At the
City's plant a small basin has been provided. At
Amarillo's City Water Reclamation Plant, two lined
basins with a total of 3 day's storage capacity are
part of the water reclamation facilities. In addition
to the equalization and storage benefits, the Ama-
rill'«|sins account for a 5 to 30 ppm greater BOD
redt^non and a 5 to 15 ppm increased suspended
solids reduction.
At an industrial plant in Mexico where these
basins were not wanted and yet a consistently high
quality flow was desired, gravity sand filtration was
provided prior to cold lime treatment. This too, is
an effective means.
Without such filters or basins, the effluent user's
treatment plant operators must be prepared to ex-
ercise more careful and regular observation and
control of the water treating systems.
In summary then, we can say that in over 3 years
of experience at its two stations, the Nevada Pow-
er Company has found that sewage plant effluent
produces a water entirely suitable for industrial
cooling use when further treated by continuous
chlorination and cold lime in a solids contact treat-
ment unit.
The sewage must be biologically treated to as
great a degree as practical and if possible the ef-
fluent should be equalized so as to even out the
continuously variable qualities of the effluent.
Excellent phosphate removals and reasonable
clarities can be expected but relatively little in
hardness reduction. No other serious problems or
foaming have come about from dissolved matter.
The treated water when adequately chlorinated
may even be stored in open reservoirs with no parti-
cular slime or algae problems.
In view of the increasing demand for water by
industry and use of over 75% of its water consump-
tion for cooling, it is significant that sewage plant
effluent as an ever increasing source of supply is
proper for this use.

BIBLIOGRAPHY:
1. The Effects of Syndets on Water Softening
Joseph F. Molina Jr., and Supote Tiyaporn
2. Chapter 23 Industrial ReUse of Sewage Plant
Effluent
C. H. Scherer from Texas Manual for
Sewage Plant Operators
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Introduction
In its infancy a lake may have been a barren body of
water lacking the critical nutrients that support aqua-
tic life. With the passing of time, wind and rain trans-
ported these necessary nutrients and the lake took on
life. After an initial surge of productivity the lake
entered a long period of dynamic equilibrium, it is
during the plateau in productivity that the lake offers
the most benefits—commercially and aesthetically.
The natural useful life of a lake should be measured
in tens of thousands of years, however the contamina-
tion of man is causing extreme premature extinction
of many waters. For the last half century man has
observed the changes brought about by over fertili-
zation. Passive realization has now turned to active
concern for effective methods to control this accele-
rated aging. A realistic solution is the Dorr-Oliver
Phosphate Extraction Process.
This paper was presented at the Pacific Northwest Section
meeting of the Water Pollution Control Federation of Yaki-
ma, Washington, October 25-27, 1967 It is the property
of the WPCF and may not be published except in accord-
ance with the rules of the Federation
© 1968 by DORR-OLIVER INC, Stamford, Conn
PEP is a trade mark of Dorr-Oliver Inc
-------
-------
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\ . ...\ HFTECr OF FERTILiIE?i

T " ~'..J NATURAL EUTRCvHiCATlCN
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'V~
cr
•" «"«., «*3«.W^-'*
<-*/\«£<»tr?/»
3^r. :^cS- • H^. ^-^r/^^a-vU-- v
J^^P-v^ r"">"v. >a>| %^%-:_v-. - <^L/r2>-%;/ (<;•"-•• '/'•"-• _» " - 4 - " ,
*-^jt^ .-•••->. 4^ •---* i. - .—- .
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hosphate Extraction Process
DSD
' Orris E. A/bertson, Marketing Manager
id Robert J. Sherwood, Marketing Engineer
ater Management Systems, Dorr-Oliver Inc.
e sanitary engineer has all the tools necessary to
actively eliminate the gross quantity of organic
lutants—that is the initial 90-95% of the BOD and
;pended solids. Often, however, receiving waters
I require effluent beneficiation. There are several
ms this beneficiation may take — increased solids
noval, higher BOD and COD removal, and phos-
ate and nitrogen reduction.
Dne of the fundamental problems in stream pollu-
i is the accurate prediction of the effects of treated
nestle and industrial waste discharges upon re-
ving waters. Heretofore, the greatest emphasis
; been assigned to the influence of the organic
ste residuals upon the oxygen resources of the
;am. However, the oxygen yardstick, established
the ^tey BOD concept, although frequently use-
can^psatisfaclorily account for the total pollu-
lal potential of a treated effluent.
Vhy remove phosphorus? It is only about 6 mg/l
final effluent. One cannot see, taste or smell it in
nal effluent. Perhaps it is these very characteris-
that have slowed the efforts of many researchers
Dring the fertilization into its proper perspective.
'he magnitude of the pollution problem associated
i the phosphorus in final effluent is not generally
iprehended. For example, a final effluent con-
ling only 10-15 mg/l BOD and TSS and 6 mg/l
phosphorus has a growth potential as follows:

mg/l P Light, nutrients 400-600 mg/l algae
carbon

00-600 mg/l TSS ^ 400-600 mg/l COD

hus, the phosphorus can produce a growth re-
nse that may equal the organic pollution load in
raw sewage This realization has spurred gov-
nental efforts to develop systems which would
ride the sanitary engineer with means to remove
phosphate from plant effluents
lere has been an increasing concern over the
of economical means of abating excessive or-
c and nutrient enrichment of receiving waters
:h tb^i develop prolific growths of algae. These
e d^Bths have aesthetically deteriorated the
jce waters and often limited its economic value.
Algae scums discolor the water and, upon decom-
position, release foul odors to the water and to the
atmosphere. Filter clogging by algae cause diffi-
culties in the purification of water and increase water
treatment costs. In addition to the productivity re-
sponse to fertilization, severe secondary pollution
results from the additional oxygen requirements
associated with the ultimate decomposition of the
algal organic material.
Sanitary engineers have long recognized that do-
mestic sewage and some industrial v/astes are a
rich source of the critical nutrients which cause algae
to flourish. The degree of eutrophication, and hence
the severity of subsequent water quality problems,
is largely dependent on the supply of inorganic nitro-
gen and phosphorus. Chemical control has been
employed to prevent excessive algae blooms. Such
treatment included the periodic application of copper
sulphate or other algicides, or diversion of nutrient
rich wastes to less sensitive or less valuable receiv-
ing waters, or a combination of these measures.
These control procedures have obvious limitations
and will not be broadly utilized. Cost and subsequent
toxic effects of the best available algicides precludes
their use for continuous control of most surface
waters Furthermore, the effort of most algicides is
only temporary and does not attack the real cause
of the problem Recently, the interest in developing
a method of waste treatment which would remove
offending nutrient elements before effluent discharge
has been renewed.
SawyerO) established that phosphorus removal
offers a practical and effective way of controlling
algae growths in most surface waters. Other investi-
gators/2'^} particularly in Europe, have investigated
the role that nitrogen, in various forms, plays in the
growth of algae Much of the earlier efforts in Europe
have been directed towards removing nitrogen from
the receiving waters Only recently have their investi-
gations turned to the phosphates and the role that
phosphate and nitrogen together have on the growth
rate and quantity of algae.
Phosphorus removal may be accomplished by bio-
logical or by chemical means. Both approaches are
directed toward converting soluble and colloidal
-------
-------
Chemical removal of phosphorus
phosphorus into recoverable insoluble material. Of
the two, chemical coagulation has received the great-
est attention and several effective, but costly, chemi-
cal treatment methods'4' <5' (6'f7' have been proposed.
To date, most of these chemical treatment methods
have investigated removal of inorganic phosphate
from sewage treatment plant effluents In other inves-
tigations, the use of iron and aluminum salts has
been evaluated'8) when added directly into the aera-
tion tank of the activated sludge system. Interest has
been recently reviewed in the application of biolog-
ical mechanisms for achieving higher phosphate re-
movals without adding a tertiary stage.
The mechanism of phosphate removal by chemical
coagulation is not well understood Theoretically,
phosphorus may be removed from solution through
precipitation as an insoluble salt or by absorption
upon some insoluble solid phase. Available experi-
mental evidence indicates that both mechanisms may
be operative, particularly at low residual ohosohorus
concentrations In the case of lime coagulation, it
appears that the principal mechanism is that of pre-
cipitation as insoluble calcium phosphate salts With
iron salts and alum, absorption upon hydrated oxide
floe-particles appears to play a major role along with
the formation of an insoluble salt Pilot plant data
indicate that poor floe settling properties may require
much lower clarifier overflow rates than commoniy
employed in sewage treatment'9'.
Figure 1, developed from the reviews of Nesbitt'10'
and Clesceri'11', summarizes phosphate removal by
a number of investigators. This figure indicates that
cost appears to be the major limitation to the appli-
cation of present chemical coagulation processes.
Based on available information, the cost of chemicals
alone would range from S20 to S80 per million gallons
FIG.1-REPORTED COSTS FOR PHOSPHATE REMOVAL
O < 4.0mg/l p
A = 4.1— 6.0mg/l p
D = 6.1-8.0 mg/l p
• > 8.1 mg/lp
100
200 300 400 500
Chemical Dosage—mg/l
600
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of sewage treated for an 80-95% reduction in phos-
phorus.
In addition to the operating cost for chemicals,
there are additional structures required for tertiary
treatment. Cost of operating personnel, maintenance,
and disposal of the chemical precipitated sludge
can greatly inflate costs shown in Figure 1. Lime
treatment costs look attractive, but the cost of neu-
tralization is not included and it could increase the
cost $10-315/MG.
Under suitable conditions, soluble phosphate may
combine with a number of substances ordinarily
present in sewage or with added compounds to form
relatively insoluble complexes. The basic relationship
of residual phosphate concentrations as a function
of lime dosage normally is similar to a monomolec-
ular curve. Precipitation with lime will generally follow
a curve, as shown in Figure 2, when the bulk of the
phosphates in the waste is orthophosphate. The
actual chemical dosage required to meet a specific
residual phosphate will be dependent upon the cal-
cium hardness and the total alkalinity of the water.
However, depending upon the clarification character-
istics of the calcium phosphate suspension, the
aclual removals could be much poorer.
^Mwyer<12>, in his discussion of lime treatment of
raw waste, indicated that the lime requirement, to
reach a pH of 11, is about 2.0 to 2.5 times the alka-
linity of the waste. He also stated that there will be
a variation in the characteristics of phosphate re-
moval from raw sewage vs. phosphate removal in the
final effluent after activated sludge treatment. In the
raw waste, the orthophosphate may constitute only
40-60% of the total phosphate, but it will usually
constitute over 90% of the total phosphate in the
effluent. In the influent raw waste, a significant por-
tion of the phosphate will be organic phosphates
and polyphosphates, which are more difficult to re-
move with lime than the orthophosphates.
Other agents may be used to produce insoluble
phosphate compounds, but these may not follow the
removal characteristics produced by lime addition.
For example, the aluminum and iron compounds re-
act to form metallic phosphates, A IPO.) or FePO<,
which are insoluble under specific pH conditions.
However, the use of aluminum or iron ions for phos-
phate removal as a tertiary treatment step produces
vast amounts of sludge. From the standpoint of
chemical cost and the sludge handling problem, the
use of these compounds has not been considered
economical. Alum, by itself, can produce as much
gal/day of additional waste sludge per
waste water.
FIG. 2-REMOVAL OF PHOSPHATES WITH LIME
f ' -' "•' ~-
50 100 150 200 250 300 350
Ca(OH), Dosage (mg/l)
More recently, investigators'8'"3) <14) nave added
Fe++, Fe+ ++, and AI + + T ions directly to the acti-
vated sludge culture. In this application, there is a
semi-stoichiometric reaction. That is, the metallic
ion dosage is a function of the phosphorus concen-
tration. Strict stoichiometric relationship is not main-
tained and the dosage is reported to be about 1.1
to 2.0 times the phosphorus requirement. On this
basis, the chemical cost could be quite practical in
those wastes having a low phosphorus content.
descend), m his summary on phosphate removal,
reported that the mixed liquor suspended solids also
has an effect on the chemical dosage Normally, the
higher the mixed liquor suspended solids concen-
tration, the higher the aluminum or iron dosage that
is required for a desired phosphate removal. With
good clarification, the addition of metallic ions to the
aeration basin can be expected to reduce the phos-
phorus level to less than 0.5 mg/l in the final effluent.
It is not possible, however, to utilize anaerobic di-
gestion for handling sludge containing phosphate
precipitated by ferric ions because the anaerobic
system will reduce the ferric to ferrous and the phos-
phate will again become soluble.
-------
-------
Biological removal of phosphorus
The concept of removing nutrients biologically can-
not be considered as new or unique In the activated
sludge system, oxygen is supplied for the use of
micro-organisms to convert carbon, hydrogen, sulfur
and nitrogen from their reduced level to a higher
oxidized state The oxidation of these basic elements
\s carried out by micro-organisms that retain energy
from these reactions for the synthesis of new cellular
protoplasm In any actively growing system, nutrient
materials are continually extracted from the environ-
ment and converted to cell tissue The rate of nutrient
removal is proportionate to the rate of net cell tissue
synthesis, and the cell tissue composition of nitrogen
and phosphorus Bacterial growth rates vary greatly
with the type of organism and with the species, but
the mixed microbial culture provided by the activated
sludge process appears to be most effective biolog-
ical system based on observed rates of phosphate
removal. Also, it is ''~>ubtful whether a select culture,
having a high phosphorus requirement, could be
maintained pure in a waste treatment system.
The nutrient removal efficiency of present-day
activated sludge systems is dependent upon the
carbon-to-phosphorus ratio of the waste being
treated. Thus, the treatment of waste with high ratios
of assimilable carbon to phosphorus — for example,
sugar wastes generally result in high efficiencies in
nutrient removal or may, in fact, require nutrient addi-
tion The use of phosphate in detergents, and their
expanded applications, has greatly reduced the
carbon-to-phosphorus ratio in domestic wastes In
turn, the phosphorus elimination by the activated
sludge culture suffered correspondingly.
Rudolfs'5' in 1947 reported phosphorus reductions
during the course of biological treatment running as
high as 75% to 90%. The average phosphate in the
raw waste was 6.5 mg/l vs. 20-30 mg/l phosphate
concentrations in today's waste.
Owens'4', investigating in 1953 sewage treatment
plant performance in Minnesota found phosphorus
removal which ranged from an average of 2%, for
primary treatment plants, to an average of 23% for
plants employing biological treatment. This removal
was equivalent to approximately 1-2 mg/l of phos-
phorus. However, the lowest phosphorus contribu-
tion reported by Owens (1 5 gm/day/cap) was equal
to the highest noted by Rudolfs Analysis of sewage
treatment plants in the Seattle, Washington area in
|1955-56 revealed comparable reductions ranging
from 15% to 40% which was equivalent to 0 8 mg/l
to 2.0 mg/l of phosphorus
The scattering of operating data between 15-50%
phosphorus removal efficiencies by sewage treat-
ment plants is probably due to waste composition
variations, mixed bacterial cultures, and microbial
protoplasm with different sludge ages.
The chief factor in the design and operation of ac-
tivated sludge systems for optimum nutrient reduc-
tion is the "load level" of the activated sludge, the
reciprocal of which is commonly referred to as
"sludge age." Figure 3 illustrates normal phos-
FIG. 3-REMOVAL OF PHOSPHATE
BY ACTIVATED SLUDGE
Extended Aeration
High Rate
Extended Aeration
High Rate
50 100 150 200 250 300 350
BOD Removed (mg/l)
-------
-------
Project objectives
iorus removal efficiencies for activated sludge sys-
ms with different sludge ages. The highest ratio of
losphorus removed to five-day BOD removed nor-
ally occurs in the high rate activated sludge system
th the sludge age of 1-2 days Conventional acti-
ted sludge systems, working in a sludge age of 3-5
lys, have a ratio of BOD removed to phosphorus
moved of about 100 1. Extended aeration systems,
th a sludge age of over twenty days, have the
*vest ratio of BOD removed to phosphorus removed
a ratio of 250-500 mg BOD/1 0 mg P
One of the most recent investigations on phos-
lorus removal by a different concept was con-
icted by Levin'15) and Shapiro!16' They reported
losphorus reduction of over 80% utilizing a con-
illed activated sludge system However, one re-
sw of phosphate literature'10' has pointed out that
losphorus concentrations in the substrate used in
;ir experiments were generally less than 5 mg/l.
ie organic material added in these tests would
counMor a phosphorus uptake of about 2 5 mg/l
synj^Bs. This is the range of removals obtained.
ie sli^n increase in phosphorus removals above
at could have resulted from absorption. Also, only
luble phosphate was reported without regard to
; total phosphate.
At San Antonio, it has been reported by Vacker,
al<17), that the phosphate removal of the Rilling
ant varies from 80-95%, averaging nearly 90% for
lengthy test period. While these removals were
sasured at the Rilling portion of the San Antonio
ant, the east and west portions of the plant do not
hibit the same magnitude of efficiency. Removal
/els in these portions of the plant are only 30-50%,
hough all three segments of this sewage plant
ire fed from the same waste stream. The exact
jchanism which produces the additional phos-
orus uptake is not established, but the following
•erating conditions have been noted:
1) D.O. greater than 2 0, generally 3-5 mg/l
2) Low liquor BOD
3) High loading on MLSS, about 0.4-0.5 Ibs
BOD/lbMLSS
4) No nitrification
Although some catiomc phosphorus uptake was
;o noted during the test period, the significance
s no^seen established. Analysis of the sludge
owe^P>nsiderable quantities of iron, aluminum,
Icium, zinc, and magnesium in addition to as much
20-22% phosphate. A number of pilot plant in-
stigations, based on this approach, are being con-
ued in other parts of the United States.
The initial project obiective was to review the exist-
ing information on phosphate removal and establish
an outline for a systems approach based on the eco-
nomical application of known phosphorus removal
parameters and also to develop new data as re-
quired After a literature study established a possible
systems approach to phosphate removal, the second
phase was initiated which included laboratory test
work necessary to prove the assumed principles of
the system. As an additional phase, commercial
scale test work was conducted where it was not
practical to conduct laboratory work or where further
study was required.
The unit operating and capital cost is considered
only as it affects the total operating and capital costs
of the sewage plant Therefore, the basic objective
was to achieve phosphate removal at the lowest
overall cost for waste treatment.
-------
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-------
"est procedures
»hase I — Phosphate Removal

While some studies evaluating the PEP system were
;onducted utilizing aluminum and ferric compounds,
he results were not economically promising and
ime was used for the balance of all the tests Only
hose results utilizing lime are herein reported.
All of the studies on phosphate removal from the
aw sewage were conducted on a batch basis in the
aboratory and the test work performed in the follow-
ig manner:

. Sufficient lime of known available CaO was added
to the raw waste samples (usually 1.0 liter) to pro-
duce a series of test vessels having a pH of 8.5-
11.0. The limed sample was flocculated 15 min-
utes and then the mixture was filtered. The total
phosphate was run on the filtrate This established
an optimum curve of residual soluble phosphate
vs. lime dosage and pH.

. For the recirculation studies, two liters of the raw
sludj^and a known dosage of lime were mixed
by ^^rechanical stirrer for 15 minutes. The lime
dosage was selected to produce the desired resid-
ual phosphorus in the supernatant based on the
test work of Step 1. The lime dosage was normally
higher due to the poorer clarification efficiency
achieved by settling vs. filtration.

. At the end of 15 minutes flocculation, the solution
was transferred into a 2-liter cylinder and allowed
to settle for one hour.

. After one hour of quiescent settling, the super-
natant was drawn off until 200 ml remained in the
cylinder. This part was classified as the underflow.

. The underflow was split and 100 ml of the under-
flow were transferred to the next unit which con-
tained one liter of sewage and 100 ml of lime. This
solution was mixed for 15 minutes and settled in
one-liter cylinder for one hour under quiescent
conditions.
. After one hour, the supernatant was drawn off until
200 ml remained, then the procedure described
in Step 4 above was repeated for two or more
steps which would then establish the recycle
equilibrium.
Analyses were then conducted on the supernatant
>r to^^phosphate, pH, suspended solids, and,
'her^^bmed necessary, calcium, COD, and BOD
ata were also collected. Soluble phosphate data
as only collected as an adjunct to the total phos-
hate determination as was alkalinity and hardness
iformation
Concurrent tests were conducted, without the
solids recirculation, to establish the chemical re-
quirements without solids recycle. The supernatant
liquor was analyzed as noted above for the recircu-
lated tests.
Phase II — Solids Handling
After Phase I process evaluation established the
character of the waste sludge to be produced by
the system, laboratory tests were carried out at Dorr-
Oliver's research and testing laboratories In this
laboratory, a 12" fluidized bed reactor was used to
combust at 1600°F a mixture of sewage sludge and
calcium carbonate sludge. (The operating tempera-
ture for calcining is 1600°F compared to the 1400°F
required for sludge combustion.) The sludge lime-
mud mixture was burned in the fluidized bed and the
-------
upfiowing gases strip the calcined materials and ash
from the bed. The ash and the calcined material were
collected by a gas cyclone and the overflow gases
scrubbed in a tray unit before discharge.
Following these tests, another study was con-
ducted at a commercial fluidized bed reactor located
in Lynnwood, Washington. The lime-mud was mixed
with a varying amount of sewage sludge and burned
in the fluidized bed reactor. The inert solids pro-
duced by combustion were collected by a dry cyclone
and wet scrubbing. The collected particles were ana-
lyzed for available calcium oxide and total calcium
oxide. Figure 5 shows the testing arrangement used
at Lynnwood. The lime-mud was metered into the
sludge conveyor which carried the cake produced
by a solid-bowl centrifuge The fluid bed reactor
was designed to combust 220 Ibs/hr of dry solids
produced from primary clarification.
The reactor was 4'-0" I.D. (inside diameter) and
had an overall height of 18'-0". The reactor is fed by
a 2%" screw feeder located in the lower portion of
the bed The mam air blower capacity is 400 scfm
giving the reactor an input heat capacity of about
33,000 Btu/min at 4% 02 (20% excess air) in the
stack gases.
The reactor was provided with a 4" test cyclone
which could recover 95% of the +2 micron particles.
The cyclone was not insulated nor was the collec-
tion chamber, which consisted of a 2" section of
pipe isolated by two valves to allow discharge of
samples during operation. About 10% of the gas
flow passed thru the cyclone while the balance was
scrubbed in an impingement-type wet scrubber op-
erating at a 10" H20 pressure drop. The scrubbing
liquor detention time was two to three minutes in
the unit.
FIG. 5-COMBUSTION-CALCINING TEST ARRANGEMENTS
Waste Gases
t
Cyclone
t
Scrubber
Water
Ash-Calcine
FS Reactor
Sludge-
Lime Feed
Ash-Ca(OH),
Blower
-------
Test results
Phase I
A series of laboratory study tests were conducted at
a sewage plant in Ohio where removal of phosphate
was being considered In Figure 6, the phosphate
removal characteristics, as a function, of pH, are
plotted. In this figure, both the soluble phosphate
and total phosphate figures are reported. These data
confirm information published by other researchers
that soluble phosphate is more difficult to remove
than the complex and the organic fraction.
The results are reported on pH basis since this
is the easiest parameter for comparing data from
different sources. In this series of tests (Figure 6),
recirculation was practiced and the residual phos-
phate figures reported in the supernatant were ob-
tained by laboratory clarification.
A series of studies evaluating the effects of recir-
culation of a portion of the settled underflow were
conducted at a plant in Connecticut. This plant had
relatively weak waste and a low alkalinity (about 100
r^B as CaCOj) in the sewage A lime dosage of
70mg/l would achieve a pH of 8 6 and reduce the
total phosphate by about 65%. A dosage of 140
mg/1 of lime would achieve an 80% reduction of
phosphate and produce a pH of about 9.5. At the
same time, COD reductions of 65% were obtained.
In Figure 7, residual phosphate as a function of
the calcium addition is shown — with and without
recirculation. As this figure illustrates, the effect of
recirculation was to reduce the lime addition by
about 50% to achieve the same residual soluble
phosphate The effect of recirculation was that com-
parable phosphate removal could be achieved at
approximately one pH unit lower than that achieved
without recirculation.
In the data of Figure 7, the information is presented
on the basis of soluble total phosphate to show the
effect of recirculation on the rate of calcium phos-
phate particle growth. The samples were filtered
and the filtrate analyzed for total phosphate. The
recirculation increased the rate of precipitate forma-
tion and the settling characteristics were observed
to be considerably improved with recirculation.
In a third series of tests conducted at a plant in
Colorado, residual total phosphate, with and without
recirculation, again reflected improved clarity of the
supernatant. However, at a pH of 11.0, the residual
«sphate, with and without recirculation, was iden-
I. This occured because the clarification without
recirculation improved. In contrast, residual phos-
phate without recirculation, as shown in Figure 8 at
a pH of 9 to 10 will be much higher than that expe-
rienced with recirculation.
FIG. 6-RESIDUAL PHOSPHATE VS pH (Plant B)
30
Total
FIG. 7-RESIDUAL SOLUBLE PHOSPHATE VS Ca'2 ADDITION (Plant A)
o
£ 6.0
o

I4'0
2.0
No Recirculation
Recirculation
10 15 20 25 30 35
mg Ca" Added/mg Residual Soluble Phosphate
40
-------
FIG. 8-RESIDUAL PHOSPHATE VS pH (Plant C)
FIG. 9-RESIDUAL COD VS pH (Plant C)
30
^ 25
D)
20
D.
en
O
.c

0
No Recirculation
Recirculation
7 8 9 10 11

pH
500
100
Settling
Recirculation
9

PH
10
11
TABLE I - CHARACTERISTICS OF LIME TREATED RAW WASTES (PLANT C)
Sample
No.
Raw
Settled*
1A-1B*
2B*
3B*
4A*
PH

7.5
7.5
8.5
9.5
10.3
11.0
BOD
mg/l
—
186
104
51
54
—
COD
mg/ 1
470
355
340
235
210
200
Tot. PO4'3
mg/ I
_
28.5
15.4
11.5
6.7
5.5
Total
Alkalinity
mg/ I CaCO3
222
-
272
330
272
266
Ca~2
mg/ I
40
40
49
80
66
65
Hardness
mg/ I CaCO3
200
—
238
160
126
62
'Supernatant samples
-------
-------
Visual observation of the settling characteristics
of the liquor anticipates these results The tests,
utilizing recirculation. clarify rapidly while those sam-
ples without recirculation have considerable turbid-
ity caused by the fine solids in suspension until a
pH range of 10.5-11.0 is achieved Lab tests indi-
cated that overflow rates of 2,000 gal/sq ft/day
could provide good overflow clarity when employ-
ing recirculation.
Generally, dosing the waste to a pH of less than
10.0 will increase the calcium and alkalinity of the
waste since the pH is not high enough to achieve
softening. In the series of tests in Colorado, the alka-
linity, calcium content and other important charac-
teristics of the supernatant fraction were changed
as shown in the table below
A corollary benefit of recirculation is an increase
in the efficiency of suspended solids removal in the
primary treatment step The addition of lime, com-
bined with good flocculation and settling, increases
« organic removal efficiency of the plant in the
nary settling area. Figure 9 shows the residual
COD characteristics of the plant in Ohio with and
without recirculation.
Without recirculation, there was not a great amount
of improvement in the residua! COD since good clar-
ification could not be maintained at the test condi-
tions. However, with recirculation, it was possible to
get as much as a 50% increase in COD removal at
the same pH levels. Visual observation of the sam-
ples showed extremely good clarity when compared
to those tests without recirculation. This better clar-
ification efficiency, as noted by the increased COD
removal, also improves removal of the calcium phos-
phate particles from the supernatant liquor.
The COD removal characteristics of a stronger
waste, such as that previously reported in Colorado,
are shown in Figure 10. Quiescent settling of the
waste for one hour reduced the COD from about
475 parts to a little over 350 mg/l. With recircula-
tion and operating at a pH of 9.5 to 10, it was possi-
ble to reduce the residual COD down to 220-250
mg/l. All the test points shown in this figure are with
recirculation.
At this plant, the first series of tests showed ex-
tremely poor removals utilizing lime. The floe struc-
ture was poor and the supernatant was cloudy.
of the lime used for the tests showed that
highly carbonated and contained lower avail-
able calcium oxide. These series of tests were rerun
with fresh lime and checked for available CaO with
standard acid.
Residual BOD data were run on the plants in Ohio
FIG. 10-RESIDUAL COD VS pH (Plant C)
500
450
400
Settling
o>
co 350
w-
0>

-------
FIG. 11-RESIDUAL BOD VS pH
200
175
01

o
O
n
125
£
75
50
25
Plant C
9 10 11
PH
FIG. 12-CALCIUM RECOVERY VS pH

95
12
90
> 85
o
£
E 80
:*
-------
ate. Laboratory analyses were conducted on the
solids derived from the cyclone and the scrubber
effluent for ash, total and available calcium and
phosphorus. The test analyses showed that only 7%
of the Ca++ recovered by the cyclone had reverted
to calcium carbonate even though the cyclone tem-
perature was only 1100-1200°F. All of the calcium
in the wet scrubber was in the carbonate form since
the water was recirculated and was being contacted
with the waste gases containing 16-18% C02.
The commercial scale combustion facilities at
Lynnwood, Washington were deficient in that the dry
cyclone was not insulated. The sample collection
period was approximately 10 minutes and the tem-
perature was not in excess of 500°F with 18% or
more C02 present in the stack gas. The temperature
in the sample column was sufficiently low to allow
condensation during some samples.
Composite samples of the feed lime-mud, sewage
sludge, and cyclone underflow collected during the
tests showed the analyses in Table 11 .
«e cyclone, even though it could remove the
rity of particles down to one micron, exhibited
a haziness in the waste gases indicating that a sig-
nificant portion of the ashed solids was finer than
one micron. Wet scrubbing was necessary to clean
the gases to meet air pollution requirements.
The percent available lime in the cyclone under-
flows varied from 79.6% to 90%. The 56% avail-
able lime was that which was found in the ash of the
feed sludge without lime added to the reactor Avail-
able lime in the overflow stream from the DorrClone^
varied from 43.7% to 70%. (Table 111)
It was necessary to feed a small amount of sludge
feed to the reactor at all times. The lime-mud was
sufficiently dry to cause binding of the feed screw
unless the sewage sludge was added The weight of
sludge to the reactor was 25-75 Ibs. total solids per
hour during the majority of the tests The reactor
was fed 420-630 Ibs/hr of lime-mud utilizing 380-
400 scfm air at 1.0% to 3.0% 02.
TABLE II - FEED/PRODUCT ANALYSES
Total Available
CaO CaO Volatiles
Sewage
Lime Mud
Cyclone U'Flow
1.0
36.8
59.0
82
0.74
47.2
TABLE III —ANALYSES OF PRODUCTS
Available CaO/Total CaO
Time Sample No. Temp — °F

10:50
11:20
13:05
13:25
16:35
16:42
16:46
17:04
17:34
18:11

1
2
3
4
5
6
7
8
9
10
Bed
1680
1560
1610
1490
1640
1600
1580
1480
1400
1320
FB*
1650
1670
1780
1790
1800
1800
1800
1780
1760
1740
Cyclone
%
5.6
86.2
87.5
83.5
79.6
-
90.0
-
-
_
Scrubber U'F
%
_
64.5
62.8
58.4
64.8
54.0
60.0
-
-
—
D/C**O'F
%
—
70.0
59.0
50.0
61.6
56.0
58.2
56.8
56.2
43.7
'Feedboard space of reactor
**Ash cyclone (DorrClone)
-------
Discussion of results
The test results and data analyses indicated that
about 90% phosphate removal was easily obtained
at a cost commensurate with present capital and
operating costs of activated sludge treatment plants.
The operating costs increase when removals of 95%
and higher are required. However, (or many receiv-
ing streams, high degrees of phosphate removal are
not justified, and particularly so, if correspondingly
high organic carbon removals are not simultaneously
obtained.
The carbonaceous material entering a receiving
water is broken down by bacteria to its lowest oxi-
dized state, C05 and H2O, or in the benthal deposits,
the reduced state of C02 and CH4. The C05 pro-
duced by the bacteria are utilized by the algae as a
carbon source. Futhermore, benthal deposits act
as a reservoir of nutrients which becomes available
during the spring turnover of lakes.
There is a symbiotic relationship between the bac-
teria and algae. Effluent requirements of BOD, total
suspended solids, and phosphate should be con-
sidered in this light. The State of Pennsylvania re-
cently took steps which were consistent with the
above approach in requiring treatment plants in a
specific watershed area to produce effluents not
greater than 4 mg/l BOD and 0.2 mg/l P.
In the subsequent discussion of removing phos-
phate with calcium, we will refer to it as calcium
phosphate. It is not practical to differentiate between
the many possible forms of insoluble phosphate that
might be present. The chemistry of phosphate is not
precise, and it is particularly difficult in the hetero-
geneous mixture of ions present in sewage. When
calcium phosphate waste sludges are calculated,
they will be considered on the basis of tri-calcium
phosphate, although other forms may be present.
Phase I
Laboratory data established that the chemical treat-
ment of the raw waste is an efficient means of remov-
ing the bulk of the phosphate in the sewage. Not only
is the majority of the phosphate removed, but also
substantial increases in BOD removal are achieved.
In the tertiary treatment system for phosphate re-
moval, a proportion of the phosphate is removed by
primary and activated sludge. After that, it is neces-
sary to add lime or another coagulant to reduce the
FIG. 13-TERTIARY TREATMENT CHEMICAL REQUIRED
r
Tertiary
Ca(OH), Dose
FIG. 14-PEP SYSTEM CHEMICAL REQUIREMENTS
r •
PEP
Ca(OH), Dose
14
-------
phosphate to the desired level. The chemical require-
ments for this procedure is quite high In addition,
substantial equipment requirements are required.
Graphical representation of the tertiary treatment
chemical efficiency is shown in Figure 13 which
illustrates a monomolecular relationship of residual
phosphate to lime dosage.
In contrast, if the chemical treatment is practiced
first and the residual scavanged by biological treat-
ment, we get a removal characteristic as shown in
Figure 14. The test results establish that this method,
in addition to the recirculation of a substantial por-
tion of the clarifier underflow after flocculation, can
reduce lime requirements by as much as 60-75%.
The higher removals of phosphate at lower pH's
are most likely due to the recirculation of calcium
phosphate nuclei. This nuclei would act as a seed
for increasing the rate of phosphate removal from
solution. This may also account for the excellent
settling characteristics of the raw waste stream after
mixed with the recycle solids for short contact times.
lei theory is reinforced by descent) who
that colloidal chemical studies showed that
at a pH of 11, the pre-dominant calcium phosphate
compound is hydroxylapatite which may be mainly
micro-crystalline and therefore difficult to settle.
Using lime, the detention time in the Flocculator
greatly influences the efficiency of phosphate re-
moval. Detention times of one hour have been
required for many applications. It would appear that
considerable time is required to build the calcium
phosphate particle to such a size that it will settle
readily. With the application of recirculation, a large
quantity of previously precipitated calcium phos-
phate particles is maintained in circulation. The
effect of this recycle is to hasten the growth of the
calcium phosphate particles by seeding effect. This
seeding allows reducing the detention time down to
not more than 15 minutes while achieving the results
noted above.
The results indicated that pH's of 9 5 to 10 in the
Flocculator-clarifier unit will be sufficient to main-
ain the overall removal of about 90%. The system
may be controlled at the pH necessary to achieve
he desired phosphate residual This may be done
?y monitoring the pH in the Flocculator-clarifier and
adding the makeup calcium hydroxide as required.
<\ curve of residual phosphate versus pH can be
3staj^|ed for a specific plant and used as a con-
rol (Sremeter for monitoring lime addition It would
also be possible to use total phosphate analysis as
he control parameter, employing a continuous
analyzer.
Phase II

The combustion testwork, operating at calcining tem-
peratures, proved that the sludge mixture is easily
handled in the present fluidized bed conception. It
would appear that the principal consideration for
producing a completely calcined product is to main-
tain the bed within known temperature limits required
for calcination.
The testwork established that if the calcium oxide
is quickly removed from the gas stream without
severe cooling, very little recarbonation will occur.
There are a number of devices on the market which
can remove the calcined material from the stack
gases, either in dry or wet form. Actually, calcination
of a lime-mud sewage sludge mixture is not unusual,
as many vacuum filter cakes may have 20-25% cal-
cium carbonate present from the lime used to con-
dition the sludge.
-------
Evaluation of the system
The resulting sludge from the PEP system will be
significantly different than that derived from a con-
ventional treatment plant or a tertiary treatment sys-
tem. The waste stream will contain much less acti-
vated sludge. Table IV shows the relative sludge
quantities from a million gallon plant employing a
conventional primary plus activated sludge system
with an additional tertiary treatment and also a com-
parison with the PEP system
While the PEP system will have considerably more
total sludge than the conventional system, the sludge
characteristics are much different. Most important,
there is much less activated sludge The tertiary
treatment system will have about two to three times
as much sludge as the PEP system.
The operating costs for sludge handling vary de-
pending upon the type of sludge. Table V shows
typical operating costs per ton for the various types
of sludge derived from sewage treatment Primary
sludge, for example, can be dewatered by vacuum
filtration or centrifugation for about S3-S5 per ton.
The sludge can be dewatered to a concentration that
is thermally self-sufficient Conversely, activated
sludge by itself or mixed with the primary sludge will
cost S15-S25 per ton for chemicals for dewater-
ing09)i20) ancj the fuel costs will be about $12-515
Calcium carbonate particles being quite heavy are
easily dewatered and require S4-S5 of fuel per ton
to calcine.
It can be considered that the operating cost for
various sludge mixtures will be dependent upon their
proportionate amount This is generally true for the
sludges produced in domestic waste treatment. The
cost will be $30-535 per ton of activated sludge to
dewater and burn and if this sludge quantity is re-
duced, it will result in a significant savings. In the
PEP flowsheet, it is possible to reduce this sludge
quantity by as much as 60%, thus achieving a sig-
nificant savings in the operating costs for handling
activated sludge.
Table VI shows the chemical costs of phosphate
removal, reported by Nesbitt(10>, and also that for
the PEP System. In this comparison, the Dorr-Oliver
lime dosage was established at 200 mg/l, even
though high efficiency has been maintained at much
lower dosages. These costs consider that the attri-
TABLE IV-WASTE SLUDGE PER MOD
TABLE V-OPERATING COSTS FOR COMBUSTION
Sludge

Primary
Secondary
CaC03,Ca3(PO
Conventional
Ib/day
1250
630
.),
Conventional
and Tertiary
Ib/day
1250
630
51 OO1
PEP
Ib/day
1780
250
18102
1880
6980
3840
Sludge
Oper. Cost - S/Ton
Dewater
Fuel
Primary
Act. Sludge
CaCO3
3-5
15-25
0
0
12-15
4-5
(1) 450 mg/ I Ca(OH)2 - 100% Recovery Ca+ +
(2) 200 mg/ I Ca(OH)2 - 80% Recovery Ca+ +
TABLE VI-CHEMICAL COSTS*
OF PHOSPHATE REMOVAL
Coagulant
Dose(mg/l) Cost$/MG-Yr
Ca(OH)i
AI2(S04)3 • 18H,0
FeCI3
Fe,(S04)3
PEP -Lime
450
225
100
150
200
10,200
17,400
25,800
9,350
3,390
'Based on 8 mg/ I P in raw sewage.
-------
Lime recovery
tion loss of calcium is 40% and that the lime cost
as 100% calcium oxide is $20 per ton. Of the 200
mg/l dosage, 120 mg/l are provided by recovery
through a combustion-calcining system
In comparing the costs, Table VI shows that the
chemical cost of the PEP system is S3390 per mil-
lion gallons per year. However, this cost is not rep-
resentative of the actual operational cost of the over-
all plant since there are substantial reductions in
the quantity of activated sludge to be handled. In
addition, since the BOD is reduced by 60% or more
across the primary system, there is correspondingly
less power required to operate the aeration system
The net effect of this reduction in power and elimi-
nation of waste activated sludge on the overall oper-
ating cost of the plant is shown in Table VII.
Table VII shows that the additional cost of calcium
hydroxide makeup at 40% attrition (including the
cost of reburnmg the calcium carbonate sludge) is
less than the savings resulting from the elimination
of 65 tons of activated sludge plus the savings in
sration power. The cost of $3390 per million gal-
per year was more than offset by a savings of
S4560 per million gallons per year in operating costs
for the waste sludge handling and power for acti-
vated sludge system. If there was no lime recovery
practiced, the cost would be $4550 a year or equiv-
alent to the savings attributed to calcium hydroxide
treatment in the primary stage.
TABLE VII-NET OPERATING COST
FOR PEP SYSTEM
$/ MG -Yr.

Tons/MG-Yr Cost Savings
Ca(OH)2 Makeup
Ca(OH)2 Recycle
Activated Sludge
Power at 11/20/kwh
122
182
-65

1830
1560
-
—
—
-
2370
2190
3390
4560
Cost w/o Lime Recovery $4550
The pilot plant and the commercial tests indicated
that calcining of lime while burning sludge is quite
practical The end product from combustion may be
collected by either dry or wet scrubbers with low
liquor detention times and then after slaking, the
lime is extracted from the ash The ash is wasted
from the system while the calcium hydroxide is re-
cycled to the primary treatment stage It is necessary
to operate the combustion unit at a slightly higher
temperature than that required for complete deodor-
izing. However, the savings attributed to the costs
of handling activated sludge makes it economical
to burn this mixture and recover the lime particularly
for the larger waste treatment plants Due to the
elimination of much of the hydrous activated sludge,
the dewatering and combustion equipment require-
ments will be no more than that required for normal
conventional treatment plants
The decision to recover lime from ash would
depend upon the size of the treatment plant, cost
of purchased lime, and ash disposal considerations.
A typical plant could have the following ash quan-
tities produced for disposal:
TABLE VIII-ASH QUANTITIES FOR ULTIMATE DISPOSAL
Conventional
PEP System- Ib/MGD
Ibs/MGD
W/Reuse
W/o Reuse
Sludge Ash
Ca3(PO4)j
CaCOa
400
400
320
300
400
320
1490
Total-Ibs/MGD 400
— cuft/MGD 4
1020
10.2
2210
22.1
-------
Application of the results
The liquid treatment portion of the phosphorus re-
moval system is shown in Figure 15. In this system,
the raw waste is flocculated and clarified preferably
in an integral unit To the raw sewage, clanfier under-
flow solids are recycled to maintain the suspended
solids in the mixture fed to the flocculator of about
500-2000 mg/l Lime is added as required to main-
tain the pH at the desired point. The lime addition is
automatically controlled and would fluctuate depend-
ing upon raw sewage flow, the alkalinity, and the
required phosphorus removal.
FIG. 15-PEP TREATMENT SYSTEM
Flocculator and
Clarifier
Recycle AS
+ + I

+ +
Complete Mixed
Aeration
WAS
Lime
Waste Sludge
18
-------
Nitrogen removal
The raw sewage from which more than 80% of
the phosphate and suspended solids and about 60-
70% BOD have been removed would be discharged
into an aeration system employing the complete-mix
activated sludge concept This system would allow
the addition of primary clanfier effluent to the aera-
tion tank without a pH correction The homogeneity
of this activated sludge system would eliminate much
of the inhibitory effect of a relatively high pH In a
plug-flow system, the high pH could have a serious
effect on the biological culture The advantages of
the complete-mix aeration system over the plug-
flow system have been described by other inves-
tigators in the sanitary field
There will be an inherent pH adjustment in the
aeration basin when the feed has a pH of 9 5 to 10 5
This will come from the liberation of the CO, by the
activated sludge culture during metabolism of the
remaining BOD Depending upon the operating para-
meters of the aerobic system, the activated sludge
Sprovide 50-100% of the necessary pH adjust-
thru the production of C02 by the microbic
. This adjustment will produce a pH below 9 0
If it is necessary to adjust the pH to a lower value
than that achieved by natural C02 production, then
acid or stack gases from the combustion unit can
be utilized.
Since the BOD added to the aeration basin will
be in the neighborhood of 50% of that normally
present, the tankage requirements may be corre-
spondently reduced In fact, this reduction must be
included as it is desirous to operate the activated
sludge cultureatahigh loading utilizing a high MLSS.
It is quite possible that the effluent BOD's will re-
flect the large reduction in the influent BOD The
significant consequence of this lower BOD to the
aeration basin is a reduction m the quantity of bio-
logical sludge which must be wasted It must be ex-
pected that there will be some calcium carbonate
precipitation in the aeration basin This will be re-
cycled with the normal activated sludge return to the
aeration basin No deleterious effect from this is
anticipated, and it should enhance settling in the
final clarifier
The final clarifier should be of the rapid sludge
return type. Removing the activated sludge from the
final clarifier quickly will minimize the amount of
leaching of phosphate into the liquor from the acti-
sludge cell. Phase separation of the activated
e may make it possible to separate the calcium
carbonate precipitation by wastage of the sludge
near the influent portion of the clarifier. The waste
activated sludge is discharged to the primary treat-
ment portion or directly to the solids handling area
If nitrogen removal is required, it will be necessary
to raise the pH in the primary clarifier effluent to 10 5
to 11 At this pH, the ammonia nitrogen can be air
stripped from the waste This can be most economi-
cally conducted in the manner described by Culp<5'
which is to pump the waste into an ammonia stripping
tower wherein air is added in large quantities
countercurrent to its sewage flow. The reported
quantities of air have been as high as 500-700 scfm
per gallon of sewage to achieve removals of 90-95%
of the ammonia when the system is operating as a
tertiary step
The characteristic removal of ammoma by air
stripping will be similar to that of the removal of phos-
phate by lime. The rate of ammonia removal is a
function of the partial pressure of the ammonia in
the waste and in the air Since there will be a down-
stream requirement for ammonia as a nutrient by the
activated sludge system, a higher residual can be
left m the primary effluent This will greatly reduce
the amount of air required to strip the ammonia from
the waste.
When nitrogen removal is practiced, it will prob-
ably be necessary to neutralize the effluent by the
addition of C02 or another acid source. One CO:
source could be the off-gases from the combustion
unit which is destroying the waste organics However,
Sawyer and BuzzelK12' were able to add the primary
effluent at a pH of 11 to an aeration chamber without
severe inhibitory effects, but there was a consider-
able buildup of calcium carbonate in the recycle
sludge stream
-------
Sludge disposal
The sludge handling flowsheet for the PEP System
is shown in Figure 16. Sludge is wasted from the
primary system at a rate necessary to maintain the
desired recirculated solids concentration. As the
waste rate will vary, a varying quantity of dilution
water must be provided. The diluted primary under-
flow is pumped through a low pressure hydrocyclone
(DorrClone) to remove all of the +150 mesh grit.
The waste primary and secondary sludge is
thickened by gravity Thickener area requirements
for the PEP approach are the same as that required
for a conventional plant of similar capacity. This is
due to the large reduction in the waste activated
sludge which is difficult to thicken and dewater. De-
watering of the predominately primary sludge will be
easily accomplished in a "long bowl" solid bowl
FIG. 16-PEP SOLIDS HANDLING SYSTEM
Waste Primary Sludge
Dilution Water
WAS
Lime
(Purchase)
Waste Gases
Thickener
MercoBowl
O'Flow
Effluent
Water
O'Flow
Dehumidifier
Scrubber
FS Reactor
Mud Clanfier
Ash
-------
Summary and conclusions
conveyor centrifuge (MercoBowl*) Chemical costs
will be lower and final cake concentrations much
higher due to the presence of CaCO3 and the re-
duced amount of activated sludge
Combustion of the sludge mixture can be effi-
ciently carried out in a fluid-bed reactor (FluoSolids
Reactor) where critical temperatures can effectively
be controlled. Waste gases carrying the sludge ash
and the dehumidified to reduce the water vapor
plume produced by the saturated gases.
The scrubber water containing ash and the slaked
lime would be transferred to a thickener where suffi-
cient dilution water (from the thickener overflow)
would be added to dissolve the calcium hydroxide
suspension. The overflow would be returned to proc-
ess and additional lime added as required to main-
tain the pH.
The ash and calcium phosphate particles are
settled and pumped through a small hydrocyclone
(DorrClone) to classify out the solids. The overflow
is returned to the thickener feed while the phosphate
is dewatered on a mechanical classifier.
1. Laboratory tests were conducted on a comple-
mentary liquid and sludge handling treatment sys-
tem which involved chemical removal of phosphate
and a greatly increased BOD removal followed
by activated sludge to reduce the balance of the
phosphate and BOD to the desired level. The PEP
System can reduce the operating costs associated
with phosphate removal to a level equivalent to
that required for conventional treatment consider-
ing the overall operating cost for waste treatment.
2. Both laboratory and commercial tests established
the fact that combustion of lime mud with sewage
sludge is practical and that calcium oxide can be
recovered from the combustion ash The com-
bustion of sludge must be conducted at a tem-
perature sufficient for calcination of the calcium
carbonate. The recovery of the calcium carbonate
as calcium oxide can be conducted at one-half
the cost of purchased lime and reduces the prob-
lem of disposing of large quantities of chemical
precipitate
3. The PEP System design is similar to that of a con-
ventional plant. Allowing for a 40-50% reduction
in the aeration tank volume, it is possible that the
PEP System plant can be built for a cost compara-
ble to a conventional activated sludge plant
employing incineration for disposal of the waste
sludge.
4. Higher removal efficiency of phosphate combined
with ammonia nitrogen removal can be achieved
with the same basic approach However, operat-
ing and capital cost will exceed conventional
treatment costs.
5. Because of the high pH in the raw waste, an addi-
tional benefit of the PEP System will be the elim-
ination of sulfide odors commonly found in the
primary treatment portion of sewage plants.
6. The complementary approach of phosphate re-
moval, using the most economical combination
of known phosphorus removal mechanisms, now
provides the engineer with an important tool to
achieve significant levels of phosphate reduction
without incurring penalties of increased operat-
ing cost, capital cost and larger land requirements.
-------
Bibliography
1. Sawyer, C. N., "Some New Aspects of Phos-
phates in Relation to Lake Fertilization". Seworjfj
and Industrial Wastes, 24.768-776 (June 195?).

2. Wuhrmann, K. 1964. "Stickstoff-und Phosphoro-
limination; Ergebuisse von Versuchen in Techniv
chen Massatab". Schweiz A. Hydrol. 26:520-558

3. Bringmann, G., 1961. "Biologische Stickstoff.
Eliminierung aus Klarwassern. Gesundhcitv
Ingenieru", 82. Jehrg., p. 233-235.

4. Owen, R. 1953. "Removal of Phosphorus from
Sewage Plant Effluent with Lime". Sewage and
Industrial Wastes 25:548-556.

5. Rudolfs, W., "Phosphates in Sewage and Sludge
Treatment", Sewage Works Journal, Vol. 19, 43-
47(1947).

6. Gulp, R. L., "Wastewater Reclamation by Tertiary
Treatment". J Water Poll. Control Fed., 35:799-
806 (June 1963).

7. Lea, W. L, Rohlich, G. A., and Katz, W. J.,
"Removal of Phosphates from Treated Sewage",
Sewage and Ind. Wasfes, 26(3):261-275 (1954).

8. Barth, E. F., "Mineral Controlled Phosphorus Re-
moval in the Activated Sludge Process". Pre-
sented at WPCF Conference, October 8-13,19G7.

9. Rohlich, G. A , "Methods for the Removal of
Phosphorus and Nitrogen from Sewage Plant
Effluents". Proceedings of the First International
Conference (1962), Advances in Water Pollution
Research, Vol. 2.

10. Nesbitt, J B, 1966. "Removal of Phosphorus
From Municipal Sewage Plant Effluents", Eng.
Res. Bull. B-93, Penn. State Univ. 54 pps.

11. Clescen, N. L., "Physical and Chemical Removal
of Nutrients". Presented at International Confoi
ence "Algae, Man and the Environment", 1967,
12. Buzzell, J. C. and Sawyer, C. N., 1966. "Removal
of Algal Nutrients from Raw Sewage with Lime"
Presented at the Missouri Water Pollution Control
Association Meeting, Jefferson City, Missouri
(March 1, 1966).

13. Tenney, M. W. and Stumm, W., 1965. "Chemical
Flocculation of Micro-organisms in Biological
Waste Treatment". Journal Water Poll. Control
Fed. 37:1370-1388.

14. Eberhardt, W A. and Nesbitt, J. B., 1967. "Chem-
ical Precipitation of Phosphate Within a High
Rate Bio-oxidation System". Presented at 22nd
Annual Purdue Industrial Waste Conference,
Lafayette, Indiana (May 1967).

15. Levin, G. V., "Reducing Secondary Effluent Phos-
phorus Concentration", 1st Progress Rept., Dept.
of Sanitary Engineering and Water Resources,
Johns Hopkins Univ., April 1963.

16. Levin, G. V. and Shapiro, J., 1965. "Metabolic of
Phosphorus by Wastewater Organisms". Journal
WPCF, Vol. 37, 800-821.

17. Vacker, D., Connell, C. H., and Wells, W. N.,
"Phosphate Removal Through Municipal Waste-
water Treatment at San Antonio, Texas". Journal
WPCF, May, 1967, pg. 750-771.

18. Krause, F., "Softening Plant Reclaims Lime
Sludge by Fluid Bed Roasting". Water Works
Engineering, April 1957.

19. Albertson, O. E. and Guidi, E. J., "Centrifugation
of Waste Sludges". Presented at WPCF Confer-
ence Atlantic City, New Jersey (October 1965).

20. Burd, R. S., "A Study of Sludge Handling and Dis-
posal", Contract No. PH 86-66-92 Dow Chemical
Co., June 1966.
Note: FS, FluoSohds, DorrClone, MercoBowl. FlocouU.o, .1 * .^,stered trademarks of Dorr-O.iver Inc
-------
Bulletin No. PEP-1
INCORPORATED
nternational Headquarters • Stamford, Connecticut
.'125-27 Maryland Avenue
Baltimore 18, Maryland

'eterans' of Foreign Wars Building
;uite913, 406 W. 34th St.
iansas City, Missouri

400 Westchester Drive
.O. Box12167
alias, Texas

364 Peachtree Road N.W.
tlanta, Georgia 30305

30 South York
mhurst, Illinois

130 Atlantic Avenue
uite 109,
3ng Raar.h California 90807
7710 Computer Avenue
Minneapolis, Minnesota 55424

1646 West Lane Avenue
Columbus 21, Ohio

2900 Glascock Street
Oakland 1, California

3813 Hillsboro Road
Nashville, Tennessee 37215

420 First Avenue, West
Seattle, Washington 98119

308 Park Place Building
Camp Hill, Pennsylvania 17011

77 Havemeyer Lane
Stamford, Connecticut
{(ices, associated companies and representatives in the principal cities of the world.
Printed in U.S A
-------
®
Technical Reprint T-208
PHOSPHATE REMOVAL
BY
CHEMICAL PRECIPITATION
J. H. DUFF
R. DVORIN
E. Salem
PRESENTED AT
Second Workshop on Phosphorus Removal
Sponsored by: U.S. Department of
the Interior, Federal Water Pollution
Control Administration
Chicago, III. June 26 - 27, 1968
Graver Water Conditioning Co.
U.S. HIGHWAY 22, UNION, N.J.
DIVISION UNION TANK CAR COMPANY
GRAVER WATER CONDITIONING CO. - DIVISION: UNION TANK CAR CO.
-------
INTRODUCTION

Properly treated sewage effluent can be a valuable source of

industrial process water, cooling water and boiler feedwater. This is

particularly true in the chronically water short-industrial areas in

the Southwest and West. (1) In 1946, the first of many Graver plants

designed to recover industrial water from treated sewage went on stream

to supply a Kansas oil company with cooling water. Experience at this

installation, and others, indicated to users that phosphate reduction

to low levels was necessary to avoid phosphate scale deposition on heat

exchange surfaces. As a result of this need, industrial technology

rapidly developed to the point where phosphate reduction to levels of less

than 1 ppm PO^ as CaCOg (0.6 ppm as PO^, 0.2 ppm as P) became routine.

This industrial technology may now be applied to waste treatment

facilities where phosphate reduction is necessary as part of an overall

effluent upgrading program. Principal equipment and operating costs are

available, based on many long term large scale industrial installations.

PRINCIPLES OF PHOSPHATE REDUCTION

Phosphates may be removed from solutions by precipitation. Some

of the possible reactions are shown in Figure 1. Commercial factors limit

the chemical reagents applicable. The principal reagents used are lime (CaO)

and alum (Al (SO, ) ' 18 1^0. Figure 2 is based on the results of labora-

tory jar tests run on sewage and industrial phosphate bearing wastes. The

tests were run at ambient temperatures using standard jar test procedures. (2)

In virtually all cases, both poly and ortho phosphates were present in
-------
the samples. The removal efficiency indicated is based on total phosphate,

The phosphate removal by calcium precipitation in Figure 2 is

based on tests in the pH range of 9.5 to 11. (1 ppm calcium as Ca is

equivalent to 0.6 ppm of commercial 93% quick lime-CaO).

It would appear that this phosphate removal proceeds on an

equivalent basis. This presumes the calcium demand (aside from phosphate)

of the system is satisfied. The calcium demand is essentially that re-

quired for reactions with constituents other than phosphate and to leave a

residual of 75-14-0 ppm calcium (as CaCOo) in the final treated water. It

should be pointed out that in the treatment of municipal sewage and some

industrial wastes, calcium carbonate precipitation is inhibited by as yet

unidentified materials.

Phosphate removal, using aluminum or iron salts, appears to be

less efficient than lime on an equivalent basis. The curves on Figure 2

for aluminum and iron salts are based on a pH range of 6.5 to 7.5. The

degree of phosphate removal affects the chemical efficiency, that is, the

more complete phosphate removal required, the more equivalents of pre-

cipitant per equivalent of phosphate. (1 ppm Al as CaCC>3 = 0.2 ppm of

alum ... Al (SO ) • 18 H20) .

Figure 2 is based on analytical results using filtered samples.

In both the calcium and the aluminum or iron systems, some coagulant is

required, since simple precipitation of the phosphates does not insure a

low total phosphate residual unless the suspended solids concentration is

low.
- 2 -
-------
I PROCESS DESIGN
j
)
i
i Process design must insure maximum chemical efficiency, minimum

I equipment and operating costs, and low effluent turbidity in the final

j treated water. Requirements of the ideal system are shown in Figure 3.

', The chemical treatment used must produce the required treated

water characteristics. The end use of the water determines these charac-

teristics (analysis); such as, pH, alkalinity, phosphate, hardness, sus-
i
j pended solids. For example, underground disposal requires a stable water
i
t
[ low in suspended solids, while industrial uses generally require low
i

1 dissolved and suspended solids. Knowledge of the end use requirement is
i

; needed to choose the lowest cost chemical treatment (3, 4).

To utilize most effectively the chemical treatment applied, a

proper environment must be provided. This includes rapid uniform dispersion

of all reagents into the system in their proper order. Previously formed

precipitates which enhance the rapid growth of new precipitates when pro-

vided with gentle agitation, should be present. Sufficient time must be

provided in the system for the reactions to go to completion and for maxi-

mum particle growth.

Equipment scaling is controlled by maintaining high concentrations

of previously formed precipitates in circulation so that new precipitates

form on the surfaces of existing ones. The absence of sufficient quantities

of previously formed precipitates can severely hamper equipment performance.

Precipitates must be separated from the treated water. The settled sludge

volume is minimized by mechanical thickening.
-------
kOPERATING EXPERIENCE

The Graver Water Conditioning Co. has supplied equipment for

the treatment of sewage plant effluent at a number of locations. The

designs are based principally on water re-use for boiler feedwater,

cooling tower makeup, and general plant water. (2) One of these

plants, Figure 4, treats Amarillo, Texas, municipal waste water prin-

cipally for cooling tower makeup.
J5
The first of the four Reactivators was installed at this

electric generating utility in 1958. The two 56' diameter and two 70'

diameter Reactivators have a combined rating of 13 mgd. Lime treatment

of the sewage plant effluent was chosen to provide a dependable supply

of cooling tower makeup (5).

Figure 5 shows the functional design of the Graver Reactivator.

This high rate, controlled recirculation, solids contact clarifier is

ideally suited for phosphate removal as the design incorporates all
!
features necessary. These include:

j 1. Rapid mixing and recirculation zone for flash mixing

of previously formed precipitates for treatment chemicals
|
j and incoming raw water.
I
| 2. Slow mixing and floe formation in circulation zone for

| maximum precipitate growth and adsorption.

! 3. Quiescent settling zone provides for separation of the
I
' precipitates from the upflowing treated water.

J 4. Sludge collection zone.
i
I 5. Positive sludge scraper.

6. Final thickening before sludge discharge.
-------
Figure 6 shows typical operating results obtained at this

installation. Treated water requirements are being met by almost

complete phosphate removal. For cooling water purposes, silica re-

duction is desirable and is being obtained. The chemical treatment

demand varies at this installation as does the inlet water composition.

Lime demand is estimated as the sum of the following:

Magnesium reduction

Free Carbon Dioxide

Phosphate reduction

Excess hydroxide

Operating results obtained are in excellent agreement with this method

of determination. Under the conditions shown on Figure 6, approximately

2.5 Ibs. of lime (CaO) and 0.25 Ibs. of alum are used per 1000 gallons of

Phosphate Reduction Using Alum. The 40' diameter Reactivator

operating at the County of Nassau, Water Renovation Project uses alum for

phosphate removal and as a coagulant. The purpose of this plant is to

treat water for re-injection into the ground to block sea water infiltration.

The flow diagram is shown in Figure 7. The treated water quality require-

1. Chemical constituents not to exceed U.S.P.H.S. Standards for

drinking water quality.
-------
2. Turbidity not to exceed 1 JTU.

3. COD not to exceed 5 mg/1.
Treated water quality requirements are met by coagulation and

phosphate precipitation in the Reactivator followed by polishing for

! suspended solids removal in the dual media air scour filters. Final

' polishing for organic removal is carried out in the granular activated

! carbon adsorbers.

| An important feature of the Reactivator at this installation
l

'; is the recently developed hydraulic recirculation system. Recirculation

systems as used in Reactivators as shown in Figures 4 and 5, require

electrical power to drive the mechanical circulation system. The hydraulic

recirculator utilizes the kinetic energy in the incoming raw water for the

recirculation of previously formed precipitates and the mixing of chemicals

and raw water. This equipment can be operated with either the electrically

powered mechanical recirculator or with the hydraulic recirculation system.

Figure 8 shows operating results obtained at this installation

with the hydraulic recirculator in service. At the time of these tests,

; only alum was being fed to the Reactivator although jar tests indicated

, lower turbidity levels would be obtained with a polyelectrolyte. To obtain

the results shown, 1.7 Ibs. of alum per 1000 gallons was used.

< It may be noted that the total phosphate concentration of the
!

I Reactivator effluent was 6.8 ppm as calcium carbonate, while the turbidity

! was 6 JTU. Virtually complete removal of the turbidity by filtration re-

^R suited in virtually complete removal of this residual total phosphate, thus
-------
'indicating that the major part of the phosphate leaving the Reactivator

; was suspended rather than dissolved material. We believe that with
j

;improved chemical treatment using a polyelectrolyte, the Reactivator

! effluent turbidity and total phosphate level would be significantly re-

; There is no practical limit to the size plant that can be pro-

.' vided for phosphate removal from municipal or industrial waste water.

; Clarification units, such as the Graver Reactivator, are currently in

operation in sizes ranging from 8' up to and including 175' diameter.

Commercially available equipment provides an individual unit capacity

over the entire range of 0.1 to 30 mgd. Larger flows, can be handled by

multiple unit installations. Virtually any phosphate level can be reduced

to any desired level down to a practical limit of about 1 ppm as CaCOg

(0.6 ppm POij, 0.2 ppm as PO as P).

Costs. Figure 9 is an example of a 10 mgd phosphate removal

plant using lime treatment. For the purposes of this example, the sewage

plant effluent analysis given on Figure 6 was used. The chemical dosage

levels are based on 80% phosphate reduction, that is, reduction, to a

level of 8 ppm or less, as CaCCU.

Sludge Handling. Under the conditions of this example, approxi-

mately 3 Ibs. of dry weight solids are precipitated from each 1000 gallons

of water treated. For a 10 mgd plant this is equivalent to approximately

30,000 Ibs. (15 tons) of dry solids for disposal per day. For design
-------
purposes, a blowdown sludge concentration of 5% should be used, although

concentrations obtained by operating equipment is often in the range of

10-15% solids by weight. Assuming an underflow concentration of 5% by

weight, this would be equivalent to a volume of about 70,000 gallons per

day. Sludge de-watering equipment would be required to reduce this.

Although centrifugation may be used, vacuum filtration will reduce the

moisture content so that the sludge would have a maximum moisture con-

centration of 50% by weight. This would result in a maximum of 60,000

Ibs. (30 tons) of de-watered sludge, equivalent to a daily volume of

approximately 20 cu. yards.

Phosphates are removed by chemical precipitation using standard

commercially available equipment. Raw water composition and treated water

requirements are the deciding factors in choosing between lime and alum

treatment.
-------
i BIBLIOGRAPHY
i
I

I 1. "Sewage Can Aid Water Short Areas", Petroleum Week,

November 28, 1958.

' 2. Lane, M. , "Chemical Treatment for Water Clarification", Water and

Sewage Works , July, August, September, 1959.

'• 3. Keating, R.J. ; Calise, V.J., "The Treatment of Sewage Plant

: Effluent for Water Re-Use in Process and Boiler Feed", Federation
i

of Sewage and Industrial Wastes Associations, October 12, 1954.

• U. Levy, D., Calise, V.J., "Fresh Water from Sewage", Consulting
i

' Engineer, January, 1959.

! 5. Terry, S. L., "Putting Waste Water to Work", Industrial Water
i
i Engineering, October, 1965.
-------
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-------
-------
OIL REMOVAL In 1942 at the East Chicago, Indiana,
plant of the Standard Forgings Corporation, a Graver clari-
fier 35' in diameter by 14' high was installed to remove
oil and waste matter from a plant waste flow of 750,000
gpd.
£f/*3=:
rt?
>SEWAGE PLANT EFFLUENT In 1946, Socony Vacuum,
Augusta, Kansas, installed a Graver clarifier to treat sewage
plant effluent and other streams. Graver equipment was
also put into operation for fluoride removal and the treat-
ment of refinery wastes.
SUSPENDED SOLIDS In 1944, at
the Bakelite Corporation plant in
Bound Brook, N. J., a Graver Filter
System was installed to remove sus-
pended solids from organic waste.
ELECTROPLATING WASTES In 1952,
ion exchange was used for chromic
acid recovery at Channel Master Cor-
poration, Ellenville, N. Y.
-------
than a quarter of a century, Graver has
beeroviding systems and equipment to treat in-
dustrial wastes. The successful operation of equip-
ment to remove suspended, colloidal and dissolved
solids from industries as diverse as metal finishing,
printing, paper making, fiber manufacturing, steel
mills and oil refineries attests to the experience and
knowledge acquired by Graver over the years.
Graver offers sound equipment design, authoritative
process and equipment selection, efficient field en-
gineering, highest quality fabrication and construc-
tion . . . assuring you and your consulting engineer
of undivided responsibility for solving waste treat-
ment problems. Process efficiency is assured
through extensive laboratory and pilot plant research
facilities.
CYANIDE DESTRUCTION In 1954, a continuous
automatic cyanide plant went on stream at IBM's
Endicott, N. Y., plant.
SEW
Mp
ucts
AGE PLANT EFFLUENT RE-USE FOR BOILER
ER In 1956, El Paso National Gas Prod-
ucts Co., Odessa, Texas, used sewage plant effluent,
treated by clarification, filtration and ion exchange,
for boiler feedwater.
ORGANIC (POLYOL) REMOVAL In 1964,
Wyandotte Chemical Company, Washington,
N. J., used continuous adsorption to treat
polyols in solution and make the waste water
suitable for discharge. A 4' diameter, 2_0' high
Continuous Adsorption column, employing
granular activated carbon, treats 70 gpm
(100,000 gpd).
-------
I

The Mono-Scour® filter is a T ..!
high rate automatic filter "
particularly designed to op-
erate with high suspended
solids loadings. This is pos-
sible because the filter em-
ploys dual media and air
scour. Experience has indi-
cated that when conven:
tional filter media are pre-
ceded by roughing filter
media, much longer op-
erating cycles and higher
rate capabilities are ob-
»d.
3raver Mono-Scour fil-
ter offers two-stage filtra-
tion, i.e. a relatively coarse,
low density material at the
top of the filter bed, and a
finer particle polishing layer
of high density materials at
the bottom of the filter bed.
The Depth Filtration ob-
tained with combination
media permits high solids "~ ^
accumulations throughout ^
the depth of the filter bed. Certain high solids ac-
cumulations within the filter bed may not be ef-
fectively removed by conventional backwash. Effi-
cient air scour, in conjunction with backwash, is
used in the Mono-Scour filter to insure positive
bed cleaning. '
Ordinarily, subfill-less underdrain systems are ef-
fective when the turbidity load applied to the filter
is relatively light. Experience indicates that for
heavy-duty multi-media filtration, conventional
methods are frequently inadequate to prevent
localized dirt accumulations in the lower portions
of the bed. Graver Research has successfully de-
veloped the Roto-Scour System, a unique under-
* system able to meet the demanding require-
:s of heavy-duty high rate filtration. This system
has its greatest application where the turbidity load
to the filters is high, or where high filtration rates
are employed.

One condition that impairs filter efficiency is the
: • 1 r • rp
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!

fc.t»^-^. rt-i^J *»t^
gradual build-up of dirt-impregnated media between
strainers that remain untouched by ordinary
subfi!l-less underdrain systems. The Roto-Scour
Underdrain System provides great turbulence in
the entire lower portion of the media bed, scrubbing
it and eliminating "dead" areas. This scrubbing
action is induced by the swirler plate that imparts a
rotary sweeping action to the water and media
during backwash. Complete bed cleaning is possible
with the advanced Roto-Scour System.
The Roto-Scoura Underdrain System is generally
provided with an air scour system as a separate
bed cleaning step. This air scour step is par-
ticularly necessary for heavy-duty service.
Many wastes previously handled by clarifiers, such
as the effluents from steel mills, merchant mills,
sewage plants (tertiary), etc., are now treated by
filtration at considerable savings in operating costs,
space and capital investment. (Write for Bulletin
WC-133A for additional information).
-------
i-~f ~ "" ~ ~~~
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The Graver Reactivates" is a high-rate solids contact
sludge recirculation clarifier ideally suited for
chemical coagulation and clarification of waste
water. It combines flash mixing, flocculation, clari-
fication and sludge thickening into one operation.
When raw water enters the Reactivator, it is mixed
with previously formed precipitates and treatment
chemicals. The benefit of intimate contact with
solids is obtained by the full retention time pro-
vided in the mixing zone, under the conical hood,
so that by the time the water enters the outer
settling zone, the bulk of the precipitated particles
is large and dense.
The Graver Reactivator sludge removal system is
specially advantageous when treating waste waters.
esigns that use elevated open-lip concentrators, to
which the suspended solids must be carried hy-
draulically, frequently fail because part of the
sludge accumulates on the bottom and in time
builds up so that the lower ports become completely
plugged. When this occurs, it is necessary to shut
down, and shovel or sluice out the accumulated
sludge.

In the Graver Reactivator, the precipitated solids are
moved mechanically by means of scrapers across
the entire bottom of the unit to a central sump,
thereby providing positive sludge removal. The
Graver sludge removal system, including the slowly
rotating scraper, central sludge sump, and automatic
backflush and blowoff arrangements, is trouble-
free in operation and easy to control. The ability of
the Reactivator to recirculate, collect, thicken and
remove sludge, makes this machine particularly ap-
plicable to sewage tertiary treatment, metal finish-
ing, paper mills, oil refineries and steel mills. (Write
for Bulletin WC-103D for additional information).
-------
1 , ,
The Continuous Adsorption System is a fully auto-
mated countercurrent system employing adsorbents
in granular form. It is used for virtually complete re-
«val of organics, particularly refractory materials.
ste liquid is introduced continuously at the bot-
tom of the C.A. unit and flows upward through the
bed of activated carbon. A carbon retainer and upper
collector allow regenerated adsorbent to be fed into
the top of the unit, while treated water is discharged.
This operation permits the most regenerated ad-
sorbent to be in contact with the waste stream just
prior to its discharge. Acting as a "polishing" step,
this last contact cleans the waste stream to a
greater degree than is possible with fixed-bed
adsorption systems.
The contaminant-saturated carbon is dewatered and
then regenerated in a multiple hearth furnace. In
this way, the carbon is re-used approximately 30
times before new carbon is required. Colored wastes
can be cleared economically using activated carbon
in a C.A. System. This is applicable to dye wastes
and other clear but colored waste streams, as well
as to tertiary treatment. In addition, there appears
to be a definite place for the C.A. System following
biological treatment, to assure that the final ef-
fluent will meet the stringent requirements for dis-
charge set by regulatory agencies.
The Rota-Rake® provides for the gravity separation
of suspended solids from liquids. It offers maximum
separation, positive sludge removal, and complete
overload protection. Available in a wide range of
designs and sizes, the Rota - Rake is a simply de-
signed, ruggedly built unit, economical to install,
operate and maintain.
Rota-Rake installation consists of a round or
'uare, conical bottom, steel or concrete tank with
a quiescent flow feed arrangement and an overflow
effluent system. Water is fed to a central inlet well
and its velocity is reduced. Heavy solids are de-
posited on the bottom of the tank. As the water
flows radially across the unit, it settles out the
other solids, the finest particles being deposited
near the periphery where the velocity is lowest. The
water then flows into collecting launders.
For positive sludge collection and discharge with a
minimum amount of turbulence, a motor-driven,
heavy-duty, box-truss scraper continuously moves
settled solids to a central discharge sump in the
bottom of the tank. A rotating paddle in the sump
keeps the sludge moving and thickens it further.
The Rota-Rake is used as a primary clarifier for
treating paper mill effluents. With the addition of
appropriate skimming equipment, it is applicable
for the removal of floating solids or free oil. Write
for Bulletin WC-123A for additional information.
-------
Effective removal of essentially all dissolved min-
erals from fluid industrial waste is accomplished
with Graver Demineralizers. Demineralization, either
fixed bed or by the Graver Cl Process (continuous
countercurrent ion exchange), is used to convert
industrial waste water into the highest quality
process water and boiler feed-
water. As a by-product of this
water purification, valuable ma-
terials are occasionally recovered.
In some cases, the cost of the
demineralization equipment will
be more than offset by this ma-
terial savings. Waste treatment
applications include chromate and
other plating metals recovery,
Concentration of rare metals and
rare earths, and recovery of cop-
per and zinc.
In addition to demineralizers,
Graver also offers other ion ex-
change equipment including softeners, dealkalizers
and disilicizers. A complete line of packaged de-
mineralizers using the unique Partilok Strainer
subfill-less underdrain system and the Monotrol?
valve is also available. (Write for Bulletin WC-111B
for additional information).
"TT* ^ ' £ V
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"- -'---'w^-iV v-'«-.v^v«t'" ^v
>'"' "-c*-; t^rJ K" ^-it' • ir'•
II ,- _- i^^r' t>^ IV *: .-
U ^- ^^7fr.":^^'
\
T-122 Some economic aspects of white water treatment
in pulp and paper mills

T-123 Applications of ion exchange to plating plant
problems

T-124 Removing oil from water by flocculation and
filtration

T-129 The treatment of sewage plant effluent for water
re-use in process and boiler feed

T-135 Design of water clarifiers and cold process
softeners

T-136 Plating waste solutions-recovery or disposal
T-143 Plating waste treatment and chrome recovery

T-155 Recovery and re-use of boxboard mill effluent

T-163 Variations in the design of plating waste treatment
systems

T-168 Sewage can aid water short areas

T-170 Fresh water from sewage

T-175 Four integrated systems handle complex missile
plant plating solutions

T-180 Water and waste treatment for the metal finishing
industry

T-199 Countercurrent adsorption for optimum efficiency
-------
-------
USER
SERVICE
USER
SERVICE
USER
SERVICE
American Brass Co. Metal Finishing
Paramount, California (Chrome, Acid)
American Cyanamid Sodium Sulfate
Fort Worth, Texas Recovery
Armstrong Cork Co. Process Water
Lancaster, Pennsylvania (Cork Dust)
Armstrong Cork Co. Paint
Lancaster, Pennsylvania
Avco Manufacturing Co. Metal Finishing
Stratford, Connecticut (Chrome, Cyanide,
Acid, Alkali)
Borg Warner Corporation Steel Mill
Ingersoll Steel Corp.
New Castle, Indiana
Bridgeport Thermostat Division Plating
Robert Shaw-Fulton Control Co. (Chrome,
Milford, Connecticut Cyanide, Acid, Alkali)
Bristol Brass Co. Metal Finishing
Bristol, Connecticut (Chrome, Acid)
Burndy Engineering Co. Metal Finishing
Milford, Connecticut (Chrome, Cyanide,
Acid, Alkali)
I Tex Oil Co. Refinery Wastes
rmany
arbide & Carbon Chemical Co. Oily
Torrance, California Waste
Carbide & Carbon Chemical Co. Oily
Whiting, Indiana Waste
Cessna Aircraft Co. Chromic Acid
Wichita, Kansas
Channel Master Corp. Chrome Plating
Ellenville, New York
Cross Keys Foundry Chrome
Altoona, Pennsylvania
City of Dayton Tertiary Treatment
Dayton, Ohio
Delta Airlines Aircraft Washing and
Atlanta, Georgia Plating
Diamond Alkali Soda Ash Recovery
Painesville, Ohio
Donaldson Air Force Base Aircraft
Donaldson, South Carolina Washrack
Doubleday & Co, Lithography
Smithsburg, Maryland
Downingtown Paper Co. White Water
Dowmngtown, Pennsylvania
Electric Autolite Co. Plating
Decatur, Alabama
El Paso National Gas Products Co.
Odessa, Texas Tertiary Treatment
Robert Gair Division White Water
Continental Can Co.
Augusta, Georgia
General Bronze Co. Metal Finishing
Garden City, Long Island, (Chrome
New York Acid)
General Motors Corporation Oily and
New Departure Division Plating Waste
Bristol, Connecticut
General Motors Corporation Oily and
Euclid Division Metal Finishing
Hudson, Ohio
General Motors Corporation Oily Waste
Diesel Equipment Division
Grand Rapids, Michigan
Genera! Motors Corporation Plating
Ternstedt Division
Warren, Michigan
Hawthorne Paper Co. White Water
Kalamazoo, Michigan
Hercules Inc. Acetic formic acid
Wilmington, Delaware Waste-deepwell
disposal
Hercules Inc. Cotton Wash Water
Wilmington, Delaware
Hercules Powder Co. Cotton Linters
Hopewell, Virginia (Process Water)
Holland Color & Chemical Co. Dye
Holland, Michigan
Homestead Air Force Base Aircraft
Homestead, Florida Washrack
Hunter Air Force Base Aircraft Washrack
Savannah, Georgia
Inland Steel Mill waste
E. Chicago, Ind.
International Business Machines Metal
Rochester, Minnesota Finishing
(Chrome, Cyanide, Acid, Alkali)
Lincoln Air Force Base Aircraft Washrack
Lincoln, Nebraska
Lowe Paper Co. De-inking
Ridgefield, New Jersey
McGuire Air Force Base Aircraft Washrack
Wnghtstown, New Jersey
Manchester Board & Paper Co. White Water
Richmond, Virginia
The Martin Co. Metal Finishing
Orlando, Florida (Chrome, Cyanide,
Acid, Alkali)
Midwest Steel Co. Fluoride Removal
Portage, Indiana
Mobil Chemical Co. Chemical Wastes
Plamfield, New Jersey
Nassau County-Bay Park Tertiary
Sewage Plant Treatment
Hempstead, New York
Pan American Petroleum Refiner Waste
Edgewood, Texas
Phelps Dodge Co. Copper Mill
South Brunswick, New Jersey
Piedmont Co. Plating Wastes
Alta Vista, Virginia
Pine Castle Air Force Base Aircr?-'
Pine Castle, Florida Wasn-a-
Pittsburgh Plate Glass Co. Proc-= = ;
Shelby, North Carolina (Orga^;
Pyle National Co. Plating v.aste;
Aiken, South Carolina
Rayonier, Inc. White v,3te
Fernandma Beach, Florida
Rohm & Haas Trickling Fiiter EfVje-
Deer Park, Texas
Schrader Valve Co. Cyanide neutraiiza: :-
Dickson, Tennessee and Clanf-ca: rr
Syste-
Schrader Valve Co. Plating v,as:-=_
Wake Forrest, North Carolina
Shaw Air Force Base Aircraft V/as"'a'-
Shaw Field, South Carolina
Sikorsky Helicopter Division Ve'2
Stratford, Connecticut Fimsr -
Small Tube Products Chromic -: -.
Altoona, Pennsylvania
Socony Mobil Oil Co. Coking V.35:-
Beaumont, Texas
Socony Vacuum Oil Co. Refinery—Te't;"
Augusta, Kansas Treat'-e-
Standard Forgings Co. Oily v', as:-
Indiana Harbor, Indiana
Stewart Air Force Base Aircraft V,'as~T,:
Smyrna, Tennessee
Stonebridge Paper Co. White .',a':
Wilmington, Illinois
Superior Electric Co. Plat -
Bristol, Connecticut
Texas Company Refine-.
Anacortes, Washington
Triangle Conduit & Cable Co. Y<" t
Landisville, New Jersey vvate1
United Shoe Machinery Co. V;v
S. 0. & C. Division Finishing (Chr3
Ansonia, Connecticut " Cyanide, Acid, A"- _l
U. S. Steel Corporation Oily Slur.
In/in Works
Dravosburg, Pennsylvania
Westinghouse Electric Co. Coppe- V
Pittsburgh, Pennsylvania
Whippany Paperboard Co. White .'.2'.
Durham Mill
Riegelsville, Pennsylvania
Whippany Paperboard Co. White .', 3:
Stoneybrook Mill
Whippany, New Jersey
Whippany Paperboard Co. White .'.3' •
Eden Mill
Whippany, New Jersey
Wyandotte Chemical Co. Pd/o
Washington, New Jersey Treat — -;
Youngstown Sheet & Tube Oily ,'.a^-
Youngstown, Ohio
I ^
-------
-------
UNION TANK CAR COMPANY

WATER AND WASTEWATER TREATMENT LITERATURE
The following literature is available from the Smith & Loveless
division. Write to Robert J. Illidge, Advertising Manager,
Smith & Loveless division of Union Tank Car Company, Lenexa,
Kansas 66215.
Number Subject

500-C Pumps
601-A Pumping Stations
605 "DupliFlo"
615-F "Mon-0-Ject"
616-D "Du-0-Ject"
630 "Vac-0-Ject"
2001-C Check Valves
2010-C "Shewer Tap"
1200-B Factory-Built "Oxigest"
1220-C Field-Erected "Oxigest"
1260-A CY "Oxigest"
900-D Comminutors
50-A General Information
100-A General Information
620 Largest Pump Station
Please note page 7 of the Graver Water brochure for literature
available on industrial waste treatment. This literature can
be obtained by writing to Martin Stern, Advertising Manager,
Graver Water Conditioning Co. division of Union Tank Car Company,
Highway 22, Union, New Jersey 07083.
-------
fX

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ulP
HERE'S HOW THEY OPERATE: Beside the
~«cwage pump station is a wet well or receiving
manhole that receives the inflowing sev,age. As the
wer well level rises, the pipe 0 of the air-bubbler
.-.ystem is submerged in the sewage, causing an in-
creasing back pressure on the steady stream of air
that is being ejected into the wet well by the com-
pressor in the control panel ©. At a predeter-
mined level, this back pressure in the system actu-
ates a mercury pressure switch which energizes a
magnetic starter. One of the pumps 0 goes on
and the sewage flows out of the wet well, into the

-------
J
The interior of the Smith & Loveless pump station
is attractive, efficiently designed and clean, with
conditioned air. The station is compact, yet nil
equipment is readily accessible to the operator
Only the entrance tube of the factory-built pump
station is visible above ground, making it incon-
spicuous, quiet and vandal-proof
*?
-------
'•- StuW
!
lylUul.1 iSt'MR
Motor Adaptor
Motor-Pump Shaft
Stationary Carbon
Rotating Ceramic
Lubrication
Stainless Steel Spring
Bronze Seal Housing
Tapered Shaft
Impeller Cap Screw
Keyed Shaft Fit
Impeller
Volute
Filter
Heivy-DutyJ'ump Base
/l/l^t-. « the Smith & Loveless Ver-
0 tical Close-Coupled "Non-
Clog" Sewage Pump — the heart of the sewage pump
station. Its design and construction reflect years of
experience with over 2,500 varied pump installations
by the world's largest manufacturer of factory-built
sewage lift stations.

SEE BULLETIN 500-8

The double mechanical seal system in the Smith &
Loveless "Non-Clog" Sewage Pump provides a "dead-
tight" long-wearing seal that prevents sewage, noxious
and dangerous gases from entering the pump room.
The mechanical seal eliminates expensive replacement
of worn-out shaft sleeves, and the leakage and mainte-
nance problems of old-fashioned pump packing. When
inevitable wear makes it necessary to replace the dead-
tight seal, it can be done by one man in less than 30
minutes — a far cry from packing or seal maintenance
on other pumps on the market.

Designed for easy maintenance, the Smith & Loveless
"Non-Clog" Sewage Pump is built to close tolerances
with heavy, rugged construction.
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Through proper production timing and
coordination with the installing contrac-
tor, the Smith & Loveless sewage pump
station can be scheduled for delivery
at the installation site on time, when
needed by the contractor, with all me-
chanical equipment ready to operate.
The pump station is delivered to the
job site on special-made trucks or by
rail in the case of larger units. Complete
installation and operating instructions
are delivered with the pump station.
/ :*
Smith & Loveless sewage pump stations
are built "with the maintenance man
in mind." Cover rungs extend the lad-
der for his safe entry, and when the
cover is opened, the lights and ventilat-
ing blower turn on, automatically. The
station comes complete with under-
standable maintenance and operating
instructions, full color-coded wiring in
the control panel, easy-to-reach starter
and breaker switches — all fully iden-
tified for the operator's convenience
and safety — a dependable, patented
ventilating system and humidity con-
trol, plus ample "elbow room" so the
maintenance man can work more effi-
ciently. Every detail is designed for
easier, faster maintenance and safer,
mere dependable operation.
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fhe Aaith & Loveless "Mon-0-Ject"
;imp5i^pneuniatic ejector lift station is
i cylindrical steel chamber v\ith three in-
dividual compartments. The top com-
Dartment is easily accessible from ground
evel and houses the ejector controls and
compressor. The middle section is a com-
jination air-storage tank and chamber
'or the valves and manifold. The bottom
compartment is the sewage receiver.

The pneumatic ejector lift station is rec-
jmmended where the rated capacity is
ess than 100 GPM. A four-inch centrifu-
gal pump, designed for three-inch solids,
s the smallest which will operate with
•easonable freedom from clogging on raw
anitary sewage. Such a pump is not
ivailable with a rated capacity less than
00 GPM. Therefore, to lift smaller
lows, the pneumatic ejector is the only
atisfactory answer. Only the larger sew-
ge j^^ips can match the pneumatic
jectc^^n its ability to handle large sew-
;ge solids.

SEE BULLETIN 615
DESIGNED FOR LOWER CAPACITIES
UP TO 200 GALLONS PER MINUTE
"YPICAL INSTALLATION of a Smith
: Loveless "Mon-0-Ject" sewage lift
tati^^serving a school in the suburbs
if arrowing community.
IDEAL FOR SMALL SUBDIVISIONS
MOTELS • SCHOOLS • FACTORIES
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TWK LuVVtr: CAPACITIES
UP TO 200 GALLONS PER MINUTE
The Smith & Loveless "Du-O-Ject" du-
plex pneumatic ejV'tor lift sta.ion is the
'equivalent to two "Mon-0-Jecf sta-
tions, combined into the same structure
with dual piping and receivers. The
"Du-O-Ject" provides the added depend-
ability of complete stand-by equipment
throughout and extra capacity for peak
loads.

The "Du-O-Ject" is a cylindrical steel
chamber with three individual compart-
ments, housing the controls, the valves
and the sewage receivers. The top com-
partment is easily accessible from ground
level and houses the ejector controls and
compressors. The middle section is a
combination air-storage tank and cham-
ber for the dual piping, valves and com-
mon discharge piping into the force main.
The bottom section is divided into two
pp.irate compartments which are the
sewage receivers.

SEE BULLETIN 616
An exclusive "No-Fail" Electrode System (Patents
Pending)—composed of heavy-duty rectifiers and
capacitors, ultra-sensitive DC relays, high-accuracy
timing units and a uniquely designed, hollow elec-
trode—prevents grounding and insulation failures
that put conventional ejectors out of operation.
The "No-Fail" system makes these units the most
trouble-free sewage ejectors on the market today.
Complete specifications and infor-
mation on the "No-Fail" Electrode
System can be obtained by writing
|for the 100-page data manual on
Smith & Loveless sewage lift sta-
tions.
IDEAL FOR SMALL SUBDIVISIONS
MOTELS • SCHOOLS • FACTORIES
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» Smith & Loveless "Way-0-Matic"
umatic ejector lift station is con-
structed similar to the pump station but
with ejector pots (receivers) replacing
fhe pumps. A superior, patented control
system "weighs" the sewage to provide
dependable, trouble-free operation with
minimum maintenance.
SEE BULLETIN 610
Sewage enters the station through the
influent pipe (7), the inlet gate valve and
check valve, into the sewage receiver @.
Air displaced by the sewage is vented out
of doors through the three-way air valve
® during the filling cycle.

As the receiver fills, the weight of the
sewage causes the receiver to rotate
(see inset) around the pivot
r The unit is constructed to permit
a maximum movement of about one-
sixteenth inch.

When sewage reaches the high-water
level, a high-level microswitch (j) makes
an electrical contact which actuates a
relay to the three-way air valve (7) closing
off the vent line and opening the connec-
;ion to the compressed air supply. The
:ompressed air forces the sewage out the
ischarge manifold through the discharge
heck valve, gate valve and into the force
lain. (j).
.s the sewage level falls, the receiver
ivots back into the empty position,
•eaking the electrical contact and de-
.ergizing the three-way air valve which
ts off the air supply and reconnects
e veniline.

3NED FOR LOWER CAPACITIES
•O 200 GALLONS PER MINUTE
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The Smith & Loveless "Vac-O-Ject" pneu-
matic ejector provides dependable two-
stage lifting action, incorporating the prin-
ciple of vacuum intake and air-pressure
ejection. It is designed for installation on
a standard four-foot wet well or receiving
manhole.
As sewage rises in the wet well, the con-
trol system starts a reversible air pump
which evacuates air from the receiver.
Atmospheric pressure forces sewage up
to the receiver. When filled, the air pump
stops, reverses and ejects the sewage.
The "Vac-O-Ject" is specifically designed
for lower capacities requiring an economi-
cal installation. It has the plus value oi
duplex dependability.

SEE BULLETIN 630
The Smith & Loveless "Pres-O-Ject" is c
compact, factory-built pneumatic ejecto:
It can be specified with the conventiona
electrode system or the exclusive Sinit'
& Loveless "No-Fail" Electrode System.
Sewage flows by gravity into the sewag*
receiver. When filled, an electrode actu
ates a Solenoid valve which closes off th<
vent line and starts the air compresso
which forces air into the sewage receive-
ejecting the sewage.
Designed for capacities up to 200 G.P.M
the "Pres-O-Iect" can be installed i:
simplex or duplex arrangements. Als'
available for stored-air applications an
remote installation of compressors.
SEE BULLETIN 710
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B'
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y
95
WITH AUTOMATIC SURFACE SKIMMING*
Factory-built "Oxigest" sewage
treatment plants are designed
specifically for small subdivisions,
mobile home courts, motels, apartments, shopping centers,
resorts, hospitals, schools, factories and other small develop-
ments in outlying areas not served by municipal sewerage
facilities.
The "Oxigest" with Automatic Surface Skimmer* is a major
break-through in the maintenance and operation of small
sewage treatment plants. The non-mechanical surface skim-
mer automatically removes floating material, via an exclu-
sive Smith & Loveless hydraulic system, from the surface of
the settling basin compartment. The recirculation effect elimi-
nates operation problems, reduces maintenance.
Each diffuser assembly is readily removable (see
left)—just one of the many advanced engineer-
ing features on the "Oxigest."
Available in a variety of standard sizes,
"Oxigest" units can be installed in parallel, as
needed, to keep pace with a growing sewage
load from an expanding development. For com-
plete engineering data on this "Aerobic Diges-
tion" treatment plant, write for the 100-page
data manual on Smith & Loveless sewage treat-
ment plants.
0
A 16mm/ color-sound motion picture on Smith
& Loveless products is available through sales
representatives in principal cities.
iT-S
'Patents Pending
SEE BULLETIN 1200
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FOR MOTELS, MOBILE HOME PARKS,

SMALL SUBDIVISIONS, FACTORIES, SCHOOLS, MILITARY BASES
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For installations
with capacities from
30,000 to 500,000
gallons per day
to serve 300 to 5,000
persons in small
communities, large
growing subdivisions,
ulitary bases, resorts,
apartments and
other developments.
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SEE BULLETIN 1220

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Large field-erected "Oxigest" units provide dependable
sewage treatment with minimum maintenance. The plants
are factory-fabricated to be field-erected at the job site.
The purchaser receives a completely assembled plant
with all equipment installed on the concrete foundation
provided by the pur-
chaser. Model R "Oxi-
gests" can be installed
above ground (left) or be-
low ground (right).
Write for complete engi-
neering data manual on
Smith & Loveless sewage
treatment plants.
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Smith & Loveless offers a complete line of high-quality com-
minutors, engineered to provide continuous, automatic screen-
ing and cutting of large sewage solids into small particles
without removing the solids from the sewage flow.
The comminutor is ideal for location at a sewage treatment
plant, at sewage outfalls or for special applications at factories
or commercial establishments—where ever large sewage solids
must be screened, shredded or cut up. Smith & Loveless' com-
plete line of comminutors are backed by more than 20 years'
experience and proved by installations all over the world.
For information on the quality comminutors offered by Smith &
Loveless, write for the 100-page data manual on sewage treat-
ment plants.
SEE BUUETIN 900
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The "Shewer Tap" method for tapping sewer mains to make
house-to-sewer service connections is a fast, effective joining
method with structural strength as strong as the pipe to which
it is applied. It provides an absolutely water-tight, root-tight
connection to eliminate the major cause of infiltration in sewers.
This proven, effective sewer-tapping method is already being
used by cities all across the nation. Write for complete in-
formation on the "Shewer Tap" method.
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The sewer main is tapped quickly and auto-.
matically by the "Shewer Tap" drill which
cuts a perfectly round hole in the main.
Epoxy resin joint material is provided for
each "Shewer Tap" connection.
•-s
••'. *• \
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for free engineering data manuals on Smith & Loveless
sewage lift stations and sewage treatment plants. The
manuals contain complete installation and operation data,
selection and capacity charts, sample specifications,
accessory equipment and dimension drawings.
• Smith & Loveless' 16mm, color-sound
4 industrial motion pictures on factory-
built sewage lift stations and sew-
i age treatment plants are available
r for viewing at meetings and confer-
. i ences or in your own office via a
, unique, portable projector. Opera-
•' / tional characteristics are explained
by complete animated sequences.
The movies show the design fea-
tures, manufacture and installation
of Smith & Loveless products.

Ask for the name of the Smith & Loveless representative in your area.
Main Plant: Lenexa, Kansas
UNION
Factories:

Oakville, Ontario, Canada
Glasgow, Scotland
Brussels, Belgium
In U. S.: Smith & Loveless, Division-Union Tank Car Co., Lenexa, Kansas

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Environmental Protection Agency
T\33ion V, Library
230 South Dcc-.rborn Street
Chicago, Illinois 6060H
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