WATER  POLLUTION CONTROL RESEARCH SERIES
17010---01/70
               TREATMENT TECHNIQUES
                        FOR
               REMOVING PHOSPHORUS
            FROM MUNICIPAL WASTEWATERS
ENVIRONMENTAL PROTECTION AGENCY • WATER QUALITY OFFICE

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         WATER POLLUTION CONTROL RESEARCH SERIES

The Water Pollution Control Research Reports describe
the results and progress in the control and abatement
of pollution in our Nation's waters.  They provide a
central source of information on the research, develop-
ment, and demonstration activities in the Water Quality
Offic'e, in the Environmental Protection Agency, through
inhouse research and grants and contracts with Federal,
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industrial organizations.

Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Head, Project Reports
System, Planning and Resources Office, Office of Research
and Development, Environmental Protection Agency, Water
Quality Office, Room 1108, Washington, D. C.  202^2.

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                 TREATMENT TECHNIQUES FOR REMOVING
               PHOSPHORUS PROM MUNICIPAL WASTEWATERS
                      John J. Convery
                      Sanitary Engineer
                          Presented

                             at
       New York Water Pollution Control Association
                     New York, New York
                         Program #17010	
                  Environmental Protection Agency
                       Water Quality Office
         Advanced Waste Treatment Research Laboratory
                        Cincinnati, Ohio
                        January 29, 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402 - Price 50 cents

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                           INTRODUCTION
A great deal of work has been and is being done to develop improved
methods for removing the nutrient phosphorus from municipal waste-
waters,,  The literature is replete with articles on the sources of
phosphorus, its eutrophying effects on the water environment, the
necessity for control, and the methodology of control.

The purpose of this paper is to summarize the alternative methods
of removing phosphorus from municipal wastewaterso  The intent is
to provide perspective to those municipal officials, engineers and
operators contemplating incorporation of nutrient control measures
into their treatment facilities and to indicate that the necessary
technology is available„  Process selection will depend on specific
wastewater characteristics, existing facilities, desired effluent
quality, and economic considerations.

Processes considered include:  conventional treatment, digester
supernatant treatment, modified biological treatment, chemical addi-
tion in primary, secondary and tertiary stages of treatment, and
moving bed filtration.

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                          TABLE OF CONTENTS
  I.  PHOSPHORUS REMOVAL BY CONVENTIONAL TREATMENT




      A.  TREATMENT OF DIGESTER SUPERNATANT




      B.  BIOLOGICAL PHOSPHORUS REMOVAL




 II.  PHOSPHORUS REMOVAL BY CHEMICAL PRECIPITATION




      A.  IRON AND ALUMINUM SYSTEMS




          I.  Treatment of Raw Sewage




              a.  Iron Systems




          2.  Chemical Addition to Secondary Biological  Processes




              a«  Activated Sludge




              b.  Trickling Filters




          3.  Tertiary Treatment with Alum




      Bo  LIME TREATMENT




          10  Raw Sewage




          2o  Tertiary Treatment




III.  MOVING BED FILTRATION OF ALUM TREATED WASTEWATER

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         I.  PHOSPHORUS REMOVAL BY CONVENTIONAL TREATMENT
The conventional treatment techniques of settling and biological
oxidation are capable of removing some phosphorus as indicated in
Table 1.
        TABLE 1.  Phosphate Removal by Conventional Waste
                  Treatment Plants

                Type of                         7o
            Treatment Plant            Phosphorus Removal
Primary Sedimentation
Primary and Trickling Filter
Primary and Activated Sludge
5-15
20-30
30-50
Regardless of the complex internal mechanism of phosphate removal
(precipitation, absorption, etc0), the actual phosphorus removal that.
a conventional plant can achieve will ultimately depend upon the amount
of sludge permanently removed from the process stream.  Since some
807o of the phosphates present in sludge are solubilized during anaerobic
digestion, the higher removal efficiencies cannot be achieved unless
the recycle of untreated digester supernatant is eliminated.

A.  TREATMENT OF DIGESTER SUPERNATANT

Treatment of the digester supernatant stream separately can achieve
effective phosphorus removal.  Lime clarification and ammonia stripping
have been evaluated*•* for the treatment of digester supernatant.  The'
supernatant is first air blown to strip out C02 which raises the pH of
806 thereby reducing the lime requirements.  A lime addition- of 3 to 4
gm/1 is then added to achieve the required operating pH of 11 to 12„
At this elevated pH, the phosphorus is precipitated and the ammonia
nitrogen in the clarifier effluent (375 mg/1) can be efficiently  •,
stripped in a countercurrent tower.  At 20°C, approximately 275 ft
of air/galoois required to achieve 907» ammonia removal.  At 60 C,
about 50 ft /gal. would be required to achieve 90% removal.  However,
heating the digester supernatant to reduce the air and equipment
requirements is not economically justified.  Removal efficiencies
of the lime clarifier are shown in Table 2.

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        TABLE 2.  Results Achieved by Lime Clarification of
                  Digester Supernatant*•*

Constituent

Suspended Solids
COD
Total Carbon
Ortho - PO, as P
Total - PO^ as P
Digester
Supernatant
mg/1
1415
2840
1284
44
96
Treated
Effluent
mg/1
140
640
260
1
3.6
% :
Removal

90
77.5
79.8
97.8
96,3
Total operating costs for digester supernatant treatment including
carbon dioxide stripping, lime clarification and ammonia stripping
are estimated to be about $0.30/1,000 gal. of supernatant which is
equivalent to $0001 to $0.015/1,000 gal, of total plant flow.

A comprehensive study  to determine the least cost solution for treating
digester liquor (primary digester overflow), digester supernatant liquor,
thickener overflow and a 50% mixture of primary and waste activated
sludge has recently been completed.  A report of the findings should
be available for distribution in the near future.

B.  "BIOLOGICAL" PHOSPHORUS REMOVAL

Several activated sludge plants have historically experienced high
phosphate removal efficiencies.  The most notable is the Rilling Road
Plant at San Antonio, Texas where an average of 80% phosphate removal
was experienced during 1965»  There is conflicting evidence in the
literature as to the mechanism of phosphorus uptake.  A chemical pre-
cipitation and a biological mechanism can both be postulated to explain
the observed phenomena.  A summary of the two schools of thought is
presented by Jenkins and Menar-^.  The first hypothesis, advocated by
Sawyer, Sekikawa,'et al., Hall and Engelbrecht, and Jenkins and Menar,
states that biological removal of phosphate can only account for 207» -
307o of the influent phosphate with an activated sludge phosphorus con-
tent of 270 - 370 and standard substrate removal rates in the range of
0.4-1.0 Ib COD removed/lb MLVSS-day.  Phosphate removal in excess of
that predicted by biological growth requirements is caused by chemical
precipitation of calcium phosphate.  Simply stated, the postulated
mechanism involves:

    I.  Hydrolysis of condensed phosphate to orthophosphate;

    2o  Decreased production of C0_ through the aerator as the
        organic matter is oxidized;

                               - 2 -

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    3.  An increase in pH occurs due to the reduced CO  generation
        and removal of CCL by aeration;

    4.  Localized pH conditions exist which are favorable for the
        precipitation of calcium phosphate.

The second point of view, advocated by Levin and Shapiro, Borchardt
and Azard, and Connell and Vacker indicates that under certain con-
ditions, activated sludge is capable of removing more phosphate than
it requires for growth.  This biological uptake of excess phosphate
has been termed "luxury uptake."  It is thought by these authors that
the percentage of phosphate incorporated into the biological sludge
is affected by the growth rate of the organisms and certain process
operating parameters such as the organic loading, mixed liquor sus-.
pended solids concentration (MLSS), aeration rate, and mixed liquor
dissolved oxygen (D.0») concentration.  The design and operating
criteria reported in the literature to achieve luxury uptake of
phosphorus are shown in Table 3.^
         TABLE 3.  Conditions for "Luxury Uptake" as Reported
                   in the Literature^
         DO - mg'/l      „                          > 2oO
         Air Supply - ft /gal.                       3-7
         Hydraulic Detention
           Time - Hours                              3-6
         Organic Loading
           Ib BOD/lb MLSS day                      0.4-0.5
         MLSS - mg/1    '                          2500-4000
         Sludge Detention Time for
           Solids Separation - Hours               < 1=0
Investigations are currently being conducted to further elucidate the
mechanisms of phosphate removal by activated sludge treatment,  A 1-mgd
plant, specifically designed and operated for maximum biological up-
take of phosphorus, has been constructed and operated through a cooper-
ative effort between the Greater Manassas Sanitary District, Prince
William County, Virginia and the Federal Water Quality Administration.
The plant treatment facilities consist of a first-stage aerator, flo-
tation unit, second-stage aerator, final clarifier, chlorine contact
tank, digesters, supernatant treatment facilities and sand drying beds,
A recent report-*-^ on the operation of this plant concluded:
                              - 3 -

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    lo  Specialized design of the activated sludge plant to achieve
        removal of phosphorus by either luxury uptake and/or physical-
        chemical phenomena should be avoided0   Such removals should be
        considered a bonus when and if they occur in existing or newly
        constructed plants0

    2.  While maximum phosphorus removals (0.022 to 0.026 Ibs of P/lb
        of COD removed) were possible at a cell residence time of 306
        days, overall phosphorus removal was limited by plant design
        considerations, effluent suspended solids concentrations and
        phosphorus release during solids separation.

    3o  Total plant operating costs were estimated to be $0048/1,000
        gal., or 2 to 3 times the cost of conventional activated sludge.

    4«  Significant operating problems were experienced in handling
        the waste activated sludge which was difficult to dewater0


         II.  PHOSPHORUS REMOVAL BY CHEMICAL PRECIPITATION

The current state-of-the-art of phosphorus removal technology indicates
that chemical precipitation is the most economical method of removing
phosphorus from municipal wastewater.  Alternatives which the design
engineer must consider include the choice of chemicals (iron, aluminum
or lime) and the point of chemical addition (primary, secondary or
tertiary).  The point at which to add the chemicals is dependent to
a great extent on the other unit processes being utilized in the treat-
ment train.  Phosphorus removal is not an isolated design problem
capable of solution through independent considerations; it requires
an integrated solution consistent with all other treatment requirements.

The choice of chemical and point of addition depends on several factors
shown in Table 4.  The significance of each will become apparent in the
detailed discussions of each chemical system.

     TABLE 40  Factors Affecting Choice of Chemical and Poifft-
               of Addition for Phosphorus Removal


     10  Influent Phosphorus Level
     2o  Effluent Discharge Standard

     3.  Wastewater Characteristics
             (Alkalinity, Etc0)
     4.  Plant Size

     5.  Chemical Costs Including Transportation
     60  Sludge Handling Facilities
     7o  Ultimate Disposal Alternatives

     8,  Other Processes Utilized
                               - 4 -

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A.  IRON AND ALUMINUM SYSTEMS

    lo  Treatment of Raw Sewage

The alternative chemical, systems for phosphorus removal in the primary
are shown in Table 50  The iron and aluminum systems are discussed
together because of the similarity in chemistry, dosing requirements,
design considerations and performance.  A discussion of lime precipi-
tation in primary and tertiary treatment applications is deferred for
separate consideration.

Phosphorus removal should be thought of as a two-step operation:   preci-
pitation of the soluble phosphorus and removal of the insoluble phos-
phorus.

With the iron and aluminum systems, the primary coagulant is added first
at a dose of 1025 to 1.75 mole of metal ion per mole of soluble phos-
phorus to precipitate the soluble phosphorus.  The dosing is therefore
proportional to both the influent soluble phosphorus concentration and
flowo

With the ferrous system, a base, either Ca(OH),, or NaOH must be added
to achieve optimum flocculation in the primary.  Next the insoluble
phosphorus is removed by flocculation with anionic polymers and settled
or filtered with a device such as the Moving Bed Filter (discussed in,
detail later).

Sufficient time  (0-5 min) should be provided between dosing of the
primary coagulant and base if necessary, and dosing of the organic
polyelectrolyte to insure completion of the precipitation reactions.
This can best be determined by preliminary jar testing.  If there is
insufficient detention time or inadequate mixing conditions in the
influent sewer, separate mixing and flocculation facilities will have
to be provided.

       TABLE 5.  Alternative Chemical Systems for Phosphorus
                 Removal in the Primary


       A.  Iron:
           Ferrous Chloride - Base Without Polymer
             or Sulfate

             Commercial or    Lime or
             Waste Pickle     Sodium
             Liquor           Hydroxide

           Ferric Chloride    Without Polymer
             or Sulfate
       B0  Aluminum:

           Alum or Aluminate  Without Polymer

       Co  Lime:              Without Additives

           1 or 2 Stage

                               . 5 _

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Iron Systems

Performance results from several full-scale plants with chemical
addition in the primary are shown in Table 6.  The chemical systems
and dosing levels used are shown in Table 7.  Overall removal of sus-
pended solids, biochemical oxygen demand and phosphorus was signifi-
cantly improved.  Since these removals were attained.in existing
facilities, higher removal efficiencies can be expected with plants
especially designed for chemical treatment of raw sewage„

It is interesting to note that both forms of waste pickle liquor,
ferrous chloride (9% Fe at Mentor) and ferrous sulfate (67o-970 Fe at
Texas City), were successfully used for phosphorus removal.  When
available within reasonable hauling distances, these materials are an
inexpensive source of iron ($0.015/lb of Fe at Texas City and $0.02/lb
of Fe at Mentor, Ohio).

Several features of the Texas City, Texas operation and performance are
significantly different from the other plants mentioned.  Ferrous
sulfate was added to the raw sewage without a base or polyelectrolyte.
Very little phosphorus (0.03 mg/1 as P) was removed by primary treat-
ment.  The bulk of the phosphorus  (4.7 mg/1,as P) was removed in the
aerator and final settler to yield an overall phosphorus removal effi-
ciency of 817o with an effluent concentration of 1.1 mg/1.  The ferrous
iron was oxidized to the; ferric iron in the aerator, thereby elimina-
ting the required addition of a base such as Ca(OH),? or NaOH.  The
aerator served as an excellent collector of the iron phosphate preci-
pitate, which can be attributed to the large floe mass available in
the aerator to absorb the precipitate,- and the presence of naturally
occurring polymeric material to aid fIocculation0  A ferrous system
can be used to attain phosphorus removal in an activated sludge plant
without the use of a base or polyelectrolyte,,  However, if a base and-
polyelectrolyte were used with the ferrous system one could expect to
remove increasing amounts of phosphorus, suspended solids and BOD in
the primary thereby reducing the load on the secondary facilities.
Also, a greater portion of the phosphorus removed in the primary
would be chemically bound, thereby reducing the phosphorus concentration
in the digester supernatant return.

Experience at Mentor, Ohio indicates that addition of a base and
polyelectrolyte are necessary to efficiently remove phosphorus from
a primary plant with a ferrous system as shown in Table 8.

These data indicate that the base is more important  than the polymer.
(Compare treatment conditions 4 and 5).  The function of the base is
not well understood; it could be an olation reaction in which the
hydroxyl ions bridge between the iron molecules effecting a certain
degree of polymerization.
                               - 6 -

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            TABLE 60  Phosphorus Removal at Full-Scale  Plants Adding
                      Chemicals in the Primary
Type of Plant
Primary:
Grayling
Mentor
Average
Influent
Phosphorus
mg/1
15.5
15.7
Fe/P
mole
ratio
1.1-1.8
1.4
% Removal - Total Plant
Suspended Total
Solids BOD Range
78(61)* 58(40) 60-80
74 59

Phosphorus
, Average
72
83.5
Trickling Filter:

   Lake Odessa

Activated Sludge:
   Benton Harbor
   Texas City
*
7.5
6,2
1.55
1.7
                     89(78)    82(62)   75-95
92.5[72.5]
             *"  •&**&••£•
           84o7     72-94
   ) Without Chemical Addition
   ] Removal Efficiency Across the Primary
 COD
                                     82
90.9[65.3]
87.2
   TABLE 7.  Chemical Systems and Dosing Levels Used at  Full-Scale  Plants
             for Phosphorus Removal
         Location
               25
Grayling, Mich.
  & Lake Odessa, Mich<
Benton Harbor, Mich.

            3
Mentor, Ohio
                    11
Texas City, Texas
                 23
               Chemical

            Fed  as Fe
            NaOH^ as CaCO~
            A-23

            FeCl, as Fe
            A-23

          Waste Pickle Liquor,
            FeCl- as Fe
          A-23

          Waste Pickle Liquor,
          FeSO. as Fe
              4
                             Dose

                            15-25 mg/1
                            30-50 mg/1
                           Oo3-0«5 mg/1

                            21.0 mg/1
                             Oo3 mg/1

                              43 mg/1

                              66 mg/1
                              .4 mg/1

                              19 mg/1
 A-23 Anionic Polyelectrolyte - Product of  the Dow  Chemical  Company
&*
  Mention of a proprietary product does not  constitute  an  endorsement
  or recommendation by the Federal Government.
                                     -  7  -

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TABLE 8.  Results of Selected-Chemical Treatment in Primary Utilizing
          Waste Pickle Liquor  - Mentor, Ohio
Treatment
Conditions
1.
2.
3.
4.

5o

6,
Polymer
Lime -
Iron -
Iron -
Polymer
Iron -
Lime -
Iron -
-
67
50
50
-
43
55
43
0.5 PPM
PPM
PPM
PPM
0.5 PPM
PPM
PPM
PPM
Flow
MGD
2
2
3
4

4

4
.4
o4
.8
.6

06

.0
7o Removal
Suspended
Solids
37
48
13
5.3

58

74
BOD
24
15
30
29

62

59
COD
44
33
29
34

63


Total
Phosphorus
9.5
46
40
42

76

83 o5
    Lime - 66 PPM
    Polymer - .4 PPM
The liquid handling aspects of phosphorus removal in the primary clari-
fier are relatively straight forward and well quantified.  Sludge
handling considerations and other plant operations are also signifi-
cant, but the current data is less definitive.  Probably the..most
quantitative data available are the results at Benton Harbor   which
are shown in Table 9,
    TABLE 9.  Plant Data at Benton Harbor Using Ferric Chloride
                                                               11
                           No Chemical
                             Addition
       Chemical Addition
                  *            *
Recycle to Primary   No Recycle
Primary Clarification

  Volume Pumped, Gal/Day     53,200
  Percent Solids              3080
  Percent Volatile             64
       51,600
        4.29
         63
46,100
 4.82
  60
Mixed Liquor Data
  Suspended Solids, mg/1      2500
  Sludge Volume Index          85
  Dissolved Oxygen, mg/1       4«8
  Air Applied, cfm            4480

Digester Operation
                     3
  Gas Production - ft.,       37,800
  Gas Production - ft /lb     3.48
                 of solids
* Recycle refers to Waste Activated Sludge
        2700
         78
         5.9
        4940
       44,400
        3.82
2400
 64
 6.6
4710
40,800
  3.67
                               - 8 -

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The study at Benton Harbor was conducted in three stages, a baseline
period with no chemical addition, a second period with the addition
of ferric chloride and polymer with wasting of the activated sludge
to the primary and a third period in which there was no wasting to the
primary.  Benton Harbor utilizes the "Kraus Process" which consists
of returning a reaerated portion of the digested solids and waste acti-
vated solids to the primary.  Chemical addition increased the solids
concentration of the primary sludge from 3.8% to 4,37o,'  When wasting
activated sludge to the primary was discontinued, the solids concen-
tration increased to A.87»«  The chemical addition and removals accom-
plished in the primary benefited the operation of the "Kraus Type"
activated sludge treatment.  Dissolved oxygen in the aeration tanks
increased and the settleability of the activated sludge improved with
the sludge volume index decreasing from 85 to 78 and 64 respectively.
No quantitative data are available on the effect of various degrees of
chemical treatment in the primary on the performance of the conventional
activated sludge process,  A full-scale study to evaluate these effects
at Grand Rapids, Michigan has been supported by an FWQA grant0  A
short-term study has been carried out at Pontiac, Michigan18.  Prelim-
inary results indicate that satisfactory performance of the biological
system was maintained utilizing 757o of the design capacity.

Digester operations proceeded normally at Texas City, Mentor and at
Benton Harbor where gas production increased from 3.48 to 3.82 ft-Vlb
total volatile solids.  The soluble phosphate concentration in the
digester supernatant return was very low.

Chemical requirements for sludge conditioning at plants utilizing
ferric chloride and lime such as Pontiac, Michigan  (activated sludge)
and Wyoming, Michigan  (trickling filter) were unaffected by the iron
treatment.  Plants utilizing polymers for sludge conditioning such
as Cleveland Westerly required additional anionic polymer to neutralize
the positive charges of the iron floe18.  Vacuum filter yields were
also comparable with and without the iron treatment.  There is of
course an increase of about 207» in the total pounds of solids that
must be handled in a primary plant.  In an activated sludge plant
this would be offset in part by a reduction in the pounds of waste
activated sludge produced,

Cost Estimates

Operating costs of chemical treatment in the primary depend  on the
choice of chemical system, chemical costs, transportation costs, and
handling costs for the additional inorganic sludge.

Capital costs will include chemical storage facilities, slurry and
feeding systems and, where necessary, additional mixing and floccu-
lation facilities.  Total operating costs have been estimated for
facilities like Lake Odessa and Grayling, Michigan to range from a
possible low of $0,01/1,000 gal. to $0.05/1,000 gal25,

                               - 9 -

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The chemical costs at Mentor, Ohio, utilizing waste pickle liquor,
are estimated to be $0,,023/1,000 gal3.,  An.additional cost of
$0.01/1,000 gal. is required to handle the excess sludge through
digestion and vacuum filtration.

2.  Chemical Addition to Secondary Biological Processes

    a0  Activated Sludge.  The pioneering work in this area was
conducted by E. A. Thomas and more recently by Earth and Ettinger „
For their studies various chemicals were added to the aerator of a
100-gpd activated sludge planto  Results are shown in Table 10.


    TABLE 10.  Phosphorus Removals Obtained by Mineral Addtion
               to the Aerator
Chemical

Dose
mg/1
Phosphorus Removal
/o

None
Calcium

150
40
64
Calcium
+
Fluoride
150

6

75

    Magnesium                   20                       50
    Ferric Iron                 15                       75*
    Aluminum^ (as Alum)          20                       70*
    Aluminum (as Alum)          30
                                                         90
    Calcium                     20
    Aluminum                     5                      74-94
    (as Sodium Aluminate)
    Aluminum                    10                      90-98
    (as Sodium Aluminate)
_
 Turbid effluent

                              - 10 -

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 Sodium aluminate was  found  to  be  superior  to the other  additives  tested
 in  terms  of  phosphorus  removal efficiency  and the fact  that  it  elimi-
 nated  the-need  for  adding sulfate,  chloride or calcium  if pH control
 is  necessary„   In general the  addition of  1,4 moles  of  aluminum for
 each mole of phosphorus entering  the aeration chamber produced  a  final
 effluent  containing approximately 0.5 to 100 mg/1 phosphorus.   Optimum
 dosages ranged  from 1.2 to  106 moles of A.l+++ per mole  of P, Over-
 dosing was detrimental  to plant performance causing  an  increase in
 effluent  turbidity  and  phosphorus concentration.

 A full-scale evaluation (2  mgd) of mineral addition  conducted at
 Pomona, California  produced the results shown in Table  11.

     TABLE 11,  Results-of  Mineral  Addition to 2-mgd Plant
                at  Pomona,  California
Aluminum
Form
NaAl (OH)4
NaAl (OH) ,
NaAl (OH).
A12(S04)3
Ratio
A1:P
1:1
1.5:1
2:1
1:1
Io4:l
Overall Phosphorus
7
to
Unfiltered
78
85
90
80
90
Removal
Filtered
85
94
96
83
95
 The  results  at  Pomona  indicate  that alum was  slightly superior to
 aluminate  in terms  of  phosphorus  removal.  One problem resulting from
 the  mineral  addition was  a deterioration of effluent quality in terms
 of turbidity,,   The  changes in effluent pH and turbidity as  a function
"of aluminum  dose  are shown in Figure 1.  The  addition of either alum
 or sodium  aluminate raised the  effluent turbidity from about 4 Jackson
 Turbidity  Units (J.T.U.)  to about 20 J.T.Uo  This turbidity can be
 attributed to  the change  in pH  beyond the optimum pH for aluminum
 flocculation.   The  effluent turbidity returned to normal within two
 days after the  mineral addition was stopped.   The turbidity problem
 was  solved by  the addition of 2 mg/1 of polyelectrolyte to  the mixed
 liquor  prior to final  clarification.  The improvement in effluent
 turbidity  effected  by  the polyelectrolyte addition is shown in Figure 2,

 Before  mineral  addition was initiated at Pomona the mixed liquor sus-
 pended  solids  averaged 1,800 mg/1 and the return sludge averaged
 4,000 mg/1,,   The  solids were 75%  volatile. After aluminum  addition
 the  MLSS  increased  to  3,000 mg/1  and the RSSS increased to  8,200 mg/1.
                                -  11  -

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8.0
                            FIGURE 1
           EFFECT  OF ALUMINUM ADDITION ON  PH  AND TURBIDITY
                      OF SECONDARY EFFLUENT
                          POMONA  STUDY
                                  MINERAL ADDITION
                                   DISCONTINUED
7.5
7.0
 30
 20
 10
  0
2
6
8        10
  TIME,DAYS
12
14
16
18

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18
                                   FIGURE 2
            EFFECT OF POLYELECTROLYTE  ADDITION ON TURBIDITY OF EFFLUENT
                       DURING PHOSPHORUS REMOVAL STUDY
                                    POMONA
                           3
4        5
TIME.HRS.
6
7
8

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The solids were 617, volatile0  Because of this significant change in
the percent of volatile solids in the return sludge and mixed liquor
solids, it is imperative that the amount of sludge wasting be accurately
controlled.  If this is not done there is a distinct possibility that
not enough active bacterial solids will be retained to maintain the
treatment efficiency of the biological process„  This is particularly
significant in the extended aeration type of operation where the rates
of cell growth are Iow0
                                        4
The pilot plant results of Earth, et al., indicated that the mixed
sludge produced with mineral addition had superior settling character-
istics (SDI=1.3) compared to the biological sludge (SDI=0.5).  Digester
operation and gas production were reported to be normal„  The phosphorus
content of digester supernatant was reduced from 50 - 100 mg/1 to 10 mg/1
as P indicating that the phosphorus remained insoluble through anaerobic
digestion.

     b,,  Trickling Filters.  Direct dosing of aluminate to a trickling
filter was evaluated at Fairborn Ohio-*.  The results are shown in Table
12o  This approach cannot be recommended where high phosphorus removal
efficiency is required„

TABLE 12„  Results of Direct Dosing of Aluminate to a Trickling Filter


        Unit efficiency - Primary effluent to final effluent

                      % Removal

Dosed
Filter
Control
Filter
Total
Phosphorus
63
13
COD
74
75
S. S.
51
51
pH
7,9
7.8
A1:P
1:1

        Overall efficiency - Raw wastewater to final effluent

                         % Removal

Dosed
Filter
Control
Filter
Total
Phosphorus
64
17
COD
83
83
S.S.
84
85
PH
7.9
7.8
A1:P
1:1

                              - 14 -

-------
 Cost Estimates

 Principal operating costs for chemical addition to the aerator will be
 the cost of chemicals.  Alum at $0.24/lb* or aluminate at $0.35/lb*
 are quite comparable in performance and can be used together for precise
 pH control if necessary,,  To achieve 90% phosphorus removal with a
 wastewater containing 10 mg/1 of phosphorus in the primary effluent,
 the alum costs would be $0.024/1,000 gal. at a mole ratio of 1.4:1 Al/P.
 The only additional costs are the amortized cost of the chemical feed
 system and the operating costs associated with handling the increased
 quantity of sludge„  Total operating and maintenance costs are esti-
 mated to be $0,036/1,000 gal.

 3.  Tertiary Treatment with Alum

 Excellent phosphorus removal can be obtained by tertiary alum clarifi-
 cation.  Results of studies at the FWQA-Lebanon Pilot Plant are shown
 in Table 13.
    TABLE 13.  Results of Tertiary Alum Treatment at Lebanon, Ohio
Process Stream
Secondary Effluent
Settled Alum-Treated
Effluent
Filtered Product
Suspended
Solids, mg/1
45.6

11.0(76%)"*
1.3(97%)
Phosphate
mg/1 P0=
22.4

2.2(90%)
0.9(96%)
Turbidity
J.T.U.
12.2

1.5(88%)
0.5(96%)
Operating Conditions :
Overflow rate:    700 gpd/ft

Alum dose:         82 mg/1 .

Aluminate dose:    68 mg/1

Silica dose:        3 mg/1


Filtration rate:    3 gpm/ft
                                    Effective size of coal:  1.325 mm

                                    Effective size of sand:   .45 mm
Length of run:

Alum sludge
  concentration:
                                                             25 hrs.
                                                            1.2% by wgt<
                                    Solids concentration
                                      in backwash water :    475 mg/1
**
  Percent Removal
  cost per pound of aluminum
                               - 15 -

-------
Tertiary alum clarification, filtration and granular carbon adsorption
is being used to renovate 400-gpm of secondary effluent from the Nassau
County, New York Bay Park Plant.  Alum was chosen to minimize post
precipitation problems in the injection well and maintain chemical
equilibrium between the renovated water and the water in the aquifer.
Unlike lime sludges, alum sludges cannot be recovered and reused-
Although several recovery schemes are being investigated for alum
recovery, none has yet proven to be practical.

Alternative methods of alum sludge dewatering might include natural
freezing  where appropriate, and rotary precoat vacuum filtration.

B.  LIME TREATMENT

The chemistry of lime treatment is entirely different from the chemis-
try of the iron and alum systems.  When slaked lime, Ca(OH)2> is added
to the wastewater, it reacts with the bicarbonate alkalinity precipi-
tating CaC03.  Calcium ions also react with the orthophosphate to
precipitate hydroxylapatite Ca,. (OH) (PO, )„, the only stable calcium
phosphate phase in the alkaline pH range.  The precipitation of Mg(OH)_
begins around pH 10 and is essentially complete at pH 12.  A simpli-
fied representation of the reactions that occur are as follows:

Precipitation

     5 Ca44" + 7 OH" + 3 H2PO^ = Ca5OH(P04)3 (S) +6 H20

     Ca"1"1" + HCO~ = CaC03(S) + H20

     Mg44" + 2 OH" = Mg(OH)2(S)

Recarbonation

     Ca4"1" + 2 OH" + C02 + H20 = CaC03(S) + 2 H20

     Mg (OH) 2 + 2 C02 = Mg44" + 2 HC03

Recalcination

     CaC03 + HEAT = CaO + C02

     Mg(OH)  + HEAT = MgO + H0
                              - 16 -

-------
1,  Raw Sewage

Lime requirements for phosphorus removal are independent of the influent
phosphorus concentration and dependent on the wastewater alakalinity
and operating pH, as shown in Figure 3„

Phosphorus removal by lime treatment is a two-step process involving
the insolubilization of the various forms of phosphorus and the physical
separation of the particulate phosphorus from the wastewater.  Jar
test results on phosphorus removal from the raw wastewater, secondary
effluent and a nitrified effluent at the FWQA-DC Pilot Plant are shown
in Figures 4, 6 and 8^1.  The total soluble phosphorus (filtered) was
reduced to 0.3 mg/1 as P or less for all three wastewaters at pH 10„
However, the total phosphorus concentration was not reduced to 0.3 mg/1
by sedimentation until pH 11.5 was attained.  Two effects are accom-
plished by operation at higher pH:  (1) Mg(OH)2> a gelatinous precipi-
tate forms, aiding, clarification and (2) additional CaCC>3 forms enhancing
floe stability and settling characteristics.  Examination of Figures
5, 7 and 9^1 provides additional insight into the chemical changes that
occur as lime is added to the wastewaters.  Below pH 10, the total and
soluble calcium concentrations increase only gradually as a function
of the lime dose because part of the added calcium settles as precipi-
tates of phosphate and carbonate.  Above pH 10, the residual calcium
(total and soluble) decreased in spite of the fact that additional
lime was being added and the precipitation of phosphorus was essentially
completed.  The precipitation of most of the bicarbonate alkalinity
as calcium carbonate accounts for this decrease in the residual calcium
concentration.  Above pH 11.5, the residual calcium concentration
increases with lime dose as the precipitation of the bicarbonate alka-
linity is nearly completed.

Comparison of the soluble calcium and total residual calcium concen-
trations indicates, especially in the D.C. secondary (Figure 7), the
existence of an unsettleable precipitate as evidenced by a visual
haze.  This haze contains phosphorus and reduces overall phosphorus
removal efficiency.  The amount of haze was variable and was usually
eliminated at pH greater than 11.5 which corresponds to the pH for
completion of the Mg(OH)_ precipitation.  The haze was much less in
the raw wastewater (Figure 5) and nonexistent in the nitrified
effluent (Figure 9).

The behavior of a wastewater of moderate alakalinity (100-150 mg/1 as
CaCCO differs from highly alkaline wastewaters (350 mg/1) such as
found at Lebanon, Ohio.  Sufficient calcium carbonate is precipitated
in the pH range between 9.5 to 10 with a highly alkaline wastewater
to produce a settleable sludge, clear effluent and filterable residual
turbidity  .  In the high pH lime process  (pH = 11.5), the excess
calcium ions from the lime may be precipitated with C0? in a recar-
bonation basin and settled in a second sedimentation basin, or may be
precipitated in the first stage with Na.CO.,.


                              - 17 -

-------
   800
        TOTAL ALKALINITY (INITIAL)
           A  22(mg/l)
           Al20(mg/l]
           a 240(mg/l)
            o600(mg/l)
   600
CO
   400
   200
     0
       7
             9         10         11
                PH
             FIGURE 3
LIME REQIREMENTS  AS  A FUNCTION OF pH
     AND WASTEWATER ALKALINITY
12

-------
                A TOTAL PHOSPHORUS,UNFILTERED

                  TOTAL  PHOSPHORUSJILTERED

                0 ORTHOPHOSPHATE, UNFILTERED
                • ORTHOPHOSPHATE,FILTERED
0
  7          8          9         10         11
                      PH
                   FIGURE 4
   RESIDUAL PHOSPHORUS IN LIME TREATED  D.C
    RAW  WASTEWATER AS A FUNCTION OF pH

-------
   150
   100
OJ9
    50
     0
        OTOTAL DECANT Ca

        • SOLUBLE Ca

      - ASOLUBLE Mg
              8
11
                                                  8
                                                  6
                                                  4 d
                                                  2
          0
12
                   9        10
                       PH
                 FIGURE 5
  CALCIUM  AND MAGNESIUM  CONCENTRATIONS IN  LIME
TREATED D.C. RAW WASTEWATER AS A FUNCTION OF pH

-------
CMO
                            A TOTAL PHOSPHORUS. UNFILTERED
                            A TOTAL PHOSPHORUS,FILTERED
                            0 ORTHOPHOSPHATE, UNFILTERED
                            • ORTHOPHOSPHATE/FILTERED
    0
     7
                            pH
                         FIGURES
        RESIDUAL PHOSPHORUS IN LIME TREATED D.C
        SECONDARY  EFFLUENT AS A FUNCTION OF pH

-------
150
100
 50
      oTOTAL  DECANT Ca
      • SOLUBLE Ca
    „ A SOLUBLE Mg
    7
8
9
10
11
                                                8
                                                6
                                                4  -
                                                2
                                                0
12
                         PH
                       FIGURE  7
CALCIUM AND MAGNESIUM  CONCENTRATIONS IN LIME TREATED
    D.C. SECONDARY  EFFLUENT AS A FUNCTION OF pH

-------
   10
    8
tSJO
C/5
                    A TOTAL PHOSPHORUS.UNFILTERED
                    A TOTAL PHOSPHORUS, FILTERED

                    o ORTHOPHOSPHATE, UNFILTERED
                    • ORTHOPHOSPHATE, FILTERED
    0
     7
                           FIGURE 8
                   RESIDUAL PHOSPHORUS IN
    LIME  TREATED NITRIFIED  EFFLUENT AS  A  FUNCTION OF pH

-------
   150
   100
to*
    30
     0
             TOTAL DECANT Ca
             SOLUBLE Ca (SIMILAR TO TOTAL DECANT Ca]
             SOLUBLE Mg
      7
8
9
10
11
                                                    8
                                                    6
                                                     4    ^
                                                     2
12
                           PH
                        FIGURE 9
    CALCIUM AND MAGNESIUM CONCENTRATIONS  IN LIME
    TREATED NITRIFIED EFFLUENT AS A FUNCTION OF  pH

-------
The reactions for these alternatives are as follows:

      Ca++ + 2 OH" + C02 —> CaC03 + H2 CaCCL + 2 Na+

A flow scheme for the two-stage lime treatment process utilizing inter-
mediate recarbonation is shown in Figure 10.  The waste lime is thickened,
dewatered on a vacuum filter, recalcined in a multiple-hearth furnace at
1850°F and reused.  The COo from the recalcination furnace is used for
the recarbonation step.  Phosphorus removal by lime precipitation is a
very flexible process.  It can be designed for single-stage or two-stage
treatment of either raw wastewater or secondary effluent.  The choice of
design configuration is governed by:  (1) residual phosphorus requirements,
(2) influent wastewater characteristics and (3) other unit processes in
the treatment train.

The excellent results obtained at the FWQA-D.C. Pilot Plant.at Washington,
B.C. and the FWQA Pilot Plant at Lebanon, Ohio on physical-chemical
treatment of primary effluent are shown in Table 14.  These studies demon-
strate the excellent removals attainable on either soft or hard waters by
two-stage and single-stage lime clarification respectively.  The studies
were conducted on primary effluents.  Similar studies on raw sewage are
planned.  The operating criteria in effect when the data in Table 14 was
obtained were as follows:

                    FWQA-DC PILOT PLANT             LEBANON PILOT PLANT

Overflow rate          1100 gpd/ft2                    1400 gpd/ft2

1st stage pH           11.8 - 12.0                         9.5

Lime dose              350-400 mg/1 as CaO                 250

2nd stage pH           10-10.5

Ferric addition to     5 mg/1 as Fe+++
   2nd stage

A 10-mgd plant employing chemical clarification of raw sewage and granular
carbon adsorption is being designed at Rocky River, Ohio.  Construction
and operation of this plant is being partially financed by an FWQA
Research and Development Grant.
                                -  25  -

-------
INFLUENT'
          FIRST
          STAGE
         CLARIFIER
         C02
       HEARTH
       FURNACE
QQ
    SOLIDS WASTE
 MAKE-UP
  LIME
RtCAPBOrt
 ATION
  TANK
                       THICKENER
                        VACUUM
                        FILTER
                       FILTRATE
CtASfFIER
                                PRODUCT
                                 LIME SLUDGE
                  FLOW  SCHEME FOR
                      TWO-STAGE
                 HSGH  LIME PROCESS

-------
TABLE 14.  Results of Treatment by Lime Clarification, Filtration and
           Carbon Adsorption of Primary Effluent at Washington, E.G.-
           (I) and Lebanon, Ohio24 (II)
                           Two-Stage Lime
                           Clarification - Low
                           Alkaline Wastewater(I)
            Single-stage Lime
            Clarification - High
            Alkaline Wastewater(II)
                             mg/1
7o Removal
7o Removal
Primary Effluent
Phosphorus , P
TOC
BOD
COD
S.S.
Turbidity (J.T.U.)
Lime Clarified Effluent
Phosphorus , P
TOC
BOD
COD
s.s.
Filtered Effluent
Phosphorus
TOC
BOD
COD
S.S.
Turbidity (J.T.U.)
Carbon Effluent
Phosphorus
TOC
BOD
COD
S.S.
Turbidity (J.T.U.)
10.4
78.4
139
265
-

Oo5
27.1
42.0
86
14.8

0.39
22.6
28
66
-

6.5
4
11
-






94.8
65.2
69.7
67.6


96.2
69.9
80oO
75.0


90.6
97
95.8


8.8
76
76
192
85
55





< 1
26
25
67
10
2
< 1
10
10
27
1
1










> 89
52.3
67.2
65,0


> 89
87
87
86


   *  All analyses run by Standard Methods 12th Edition

Single-stage low pH  lime clarification followed by activated sludge treat-
ment has been suggested as a viable treatment technique to achieve 85%
phosphorus removal.  This combination of unit processes has been called
the PEP Process and  is being marketed by Dorr-Oliver,  Inc.

Rochester, New York  is presently planning a 100 mgd plant incorporating
lime clarification followed by activated sludge treatment.
    Trademark of Dorr-Oliver, Inc., Stamford, Connecticut (Use of trade name
    does not constitute an endorsement or recommendation by the Federal
    Government of the item or product mentioned.)
                               - 27 -

-------
2.  Tertiary Treatment

Single-stage and two-stage lime clarification can be applied as tertiary
treatment processes.  A notable example of two-stage tertiary lime treat-
ment is the 7.5 mgd facility at Lake Tahoe.  Phosphorus removal achieved
by tertiary lime clarification is comparable to the results previously
reported for primary effluent.

Lime requirements: for the treatment of raw wastewater or secondary
effluent at the same raw water source will differ depending on the type
of secondary treatment.  Conventional activated sludge can be expected
to increase the lime requirements because of the C02 generated.  Nitrifi-
cation can be expected to consume alkalinity and lower the lime require-
ment .
Cost Estimates

The cost of single-stage lime clarification, without recarbonation or
post filtration, for various sized plants are shown in Table 15.  A lime
requirement of 300 mg/1 as Ca(OH)2 was assumed.  Debt service charges
were based on 4 1/2% for 25 years.  Two other assumptions made for these
cost estimates are that the cost of recalcining lime is equivalent to
the cost of buying fresh lime and the cost saving associated with recal-
cining lime sludge is the cost of sludge disposal.  The biggest cost
associated with lime clarification for the larger plants is the cost of
the lime.  The cost of two-stage lime clarification exclusive of chemicals
is shown in Figure 11. °  The cost of recalcination and make-up lime is
shown in Figure 12.^0  plants smaller than about 10 mgd will use all new
lime; larger plants will use recalcined plus make-up lime.
     TABLE 15.  Total Cost of Phosphate Removal for Single-Stage
                Lime Clarification20
     SIZE OF PLANT      „         1 mgd

Capital amortization             1.25
Land amortization                 .12
Operating and maintenance        2.30
Cost of chemicals
   Lime                          1.75
Cost of sludge disposal by
   hauling to land fill
   (25-mile one-way trip)         .67
        CENTS PER 1,000 GALLONS

         10 mgd    100 mgd
          1.12
           .12
           .79

          1.75


           .67
            .84
            .12
            .50

           1.75


            .67
              250 mgd

                 .77
                 .12
                 .47

                1.75


                 .67
TOTAL
Savings if lime can be
   reclaimed
6.09
-.67
4.45
-.67
3,88
-.67
3.78

-.67
TOTAL (with recalcining)
5.42
3.78
3.21
3.11
                                 - 28 -

-------
   20.0
   10.0
C0
   0.10
                  1IIIITTiIIIII

                  COST  ADJUSTED TO MARCH, 1969
                          20.0
                          10.0
                                        .•••
      1.0
                          rs.
                                                            oo
                                                         1.0
                       jjJO.10
10.0
100
                         FIGURE 11
    COST OF TWO STAGE  LIME  CLARIFICATION  TREATMENT
                  EXCLUSIVE OF CHEMICALS

-------
  10.0
C9
€/>
   1.0
  0.10
                      i  i
                COST  ADJUSTED TO MARCH, 1969
      1.0
j	i   i  i  i  i i  i
i	i   i  i i i  i i
                                                           20.0
                                             10.0
                                              1.0
0.10
 COST OF  SOPPLYING imt FOR LIME CLARIFICATION PROCESS
            •HANTS LESS THAN  ABOUT 10 MGD USE ALL NEW LIME;
             LARGER PLANTS USE RECALCINED  PLUS MAKE UP LIME

-------
       III.  MOVING BED FILTRATION OF ALUM TREATED WASTEWATER
As mentioned earlier, phosphorus removal is a two-step process involving
insolubilization and solids separation.  An alternative to chemical
treatment and settling is chemical precipitation and filtration.  Either
a coarse media upflow filter or a multi-media downflow filter may be used,
but both have serious operational limitations.  These include:  (1) a
limited ability to handle the wide fluctuations in solids load, and
(2) potential plugging from biological growths which may occur in a fixed
bed in the presence of high organic concentrations.

A new filter technology for wastewater involves the concept of a moving
bed.  A Moving Bed Filter (MBF) developed by Johns-Manville Products
Corporation* has been operated .under test conditions for over a year,
including limited testing on the treatment of raw sewage.  A schematic
diagram of the MBF is shown in Figure 13.  This unit is basically a
sand filter with optional chemical treatment.  Particulate matter is
removed as the water passes through the sand bed.  As the filter surface
becomes clogged, the filter media is moved forward by means of a mechani-
cal diaphragm.  The clogged filter surface is hydraulically or mechani-
cally removed thereby exposing a clean filter surface.  The sand and
accumulated sludge is washed and separated.  The sand is returned to the
base of the filter.  The sand moves countercurrent to the water being
filtered.  The unit does not have to be taken off stream for backwashing.
In theory, 1% of the filter is being backwashed 100% of the time com-
pared to the conventional practice of backwashing 100% of the filter 1%
of the time.  External and more thorough cleaning of the filter media
may prove to be an important factor in minimizing problems associated
with slime growths.

Results from an 8-gpm MBF unit treating raw wastewater at Bernard's
Township, New Jersey are shown in Table 16

The Moving Bed Filter is being designed for plant capacities up to
5 mgdo  Moving bed filtration of raw wastewater followed by granular
carbon adsorption would appear to be an efficient alternative physical-
chemical treatment combination; particularly, where land is scarce or
expensive.
   Mention of a commercial product does not imply endorsement by
   the FWQA or the U. S. Government.
                              - 31 -

-------
    INFLUENT
   I
CHEMICALS
     FEED HOPPER

     DIAPHRAGM
        HYDRAULIC
          SYSTEM
.SAND
RECYCLE
           PRODUCT
            "l WATER
                                            SLUDGE
         WASH WATER
                EDUCTOR-
                          SAND WASHING
                        WASTE
                        SLUDGE
                    FIGURM3
 SCHEMATIC ARRANGEMENT  OF MOVING BED FILTER

-------
TABLE 16.  Results of Alum Coagulation and Moving Bed Filtration Treat-
           ment of Raw Wastewater at the Bernard's Township Plant
Constituent               Raw Wastewater       MBF Effluent          %
                          Concentration        Concentration      Removal
                              mg/1                 mg/1
BOD
Phosphorus as P:
Total
Ortho
Filterable
Suspended Solids
Turbidity, JTU
Test Conditions:
115

21.5
13.2
18.6
156
119

19

2,2
0.6
Oo8
27
16

83.5

90.0
95.5
95.5
83.0
86.5

                         o
   Flow Rate   2.5 gpm/ft

   Alum Dose   200 gpm/1

   Polymer     .5-.65 mg/1
The primary application for which the Movirig Bed Filter was designed is
the filtration of unsettled trickling filter effluent.  Results of the
MBF unit in this application are shown in Table 17.

Test conditions for the filtration of unsettled trickling filter effluent
were identical to the test conditions for the filtration of raw wastewater.

A 2-mgd Moving Bed Filter facility at the Borough of Manville Plant for
the treatment of unsettled trickling filter effluent is currently under
construction.  This project is being partially funded through an FWQA
Research and Development Grant.
                               - 33 -

-------
TABLE 17.  Results of Alum Coagulation and Moving Bed Filtration of
           Unsettled Trickling Filter Effluent12
   Constitutent          Unsettled Trickling
                           Filter Effluent.        MBF Effluent        %
                               mg/1                    mg/1         Removal
BOD
Phosphorus as P:
Total
Ortho
Filterable
Suspended Solids
Turbidity
40

19.1
12.9
15.5
96
41
5

0.84
0.43
0.50
7
2.9
87.3

96.1
97.0
97.1
92.8
93.0
Cost Estimates

The capital costs of a 1-mgd Moving Bed Filter are estimated to be $190,000.
Erection costs including influent pumps, electrical and plumbing are an
additional $90,000.  The total operating costs including amortization of
capital is estimated to be $0.13/1,000 gal.

Sludge disposal costs with a rotary precoat vacuum filter are estimated
at an additional $0.02 to $0.03/1,000 gal.' based on experience with water
treatment plant sludges. '
                               - 34 -

-------
                      SUMMARY AND CONCLUSIONS
There are several alternative methods available for the removal of
phosphorus including biological uptake, chemical precipitation of the
soluble phosphorus and either settling or filtration of the particulate
phosphorus.

Based on today's technology, chemical precipitation is the most practical
method of phosphorus removal.  There are numerous chemical systems available
which can be applied to raw sewage, primary effluent or secondary effluent.
The choice of chemical and point of chemical addition depend to a great
extent upon the size of plant, phosphorus discharge standard, influent
wastewater characteristics and other processes utilized in the treatment
train.

Phosphorus removal costs range from $0.13/1,000 gal. for two-stage lime
treatment of raw sewage to attain 977o removal at 1-mgd to a potential
low of $0.015/1,000 gal. for the use of waste pickle liquor in the primary
to achieve 80% phosphorus removal.

In the process of removing phosphorus, several other benefits including
better solids and BOD removal occur.  As with all pollution control, the
benefits must be weighed against the costs.
                               - 35 -

-------
                             REFERENCES
 1.   "A Study on Removal of Carbonaceous, Nitrogenous, and Phosphorus
     Materials from Concentrated Process Waste Streams," Final Report,
     FWPCA Contract No.  14-12-431,. Engineering-Science, Inc., November,
     1969.

 2.   Albertson, 0.  E.  and Sherwood, R.  J., "Phosphate Extraction Process,"
     Technical Preprint  No. 701-P, Dorr-Oliver, Inc., Stamford, Connecticut.

 3.   Annual Report  on the Water Pollution Abatement Program for Mentor,
     Lake County, Ohio,  FWPCA Grant WPRD 172-01-68, May 15, 1968 -
     August 31, 1969.

 4.   Earth, E. F. and Ettinger, M. B.,  "Mineral Controlled Phosphorus
     Removal in the Activated Sludge Process," Journal Water Pollution
     Control Federation. Vol. 39, No.  8, August,  1967, p. 1362.

 5.   Earth, E. F.,  et al., "Phosphorus  Removal from Wastewater by Direct
     Dosing of Aluminate to a Trickling Filter," Journal Water Pollution
     Control Federation, Vol. 41, No.  11, Part 1, November, 1969, p. 1932.

 6.   Earth, E. F.,  "Treatment and Control of Phosphorus in Wastewater,"
     Internal Report,  Robert A. Taft Water Research Center, Cincinnati,
     Ohio,  1968.

 7.   Berg,  E. L. and Williams, R. T.,  "Single-Stage Lime Clarification
     of -Secondary Effluent," (In Press).

 8.   Buzzell, J. C. and  Sawyer, C. N.,  "Removal of Algal Nutrients from
     Raw Wastewater with Lime," Journal Water Pollution Control Federation,
     39, R16, October, 1967 .

 9.   Farrell, J. B., et  al., "Natural Freezing for Dewatering of Aluminum
     Hydroxide Sludge,"  U. S. Department of the Interior, FWPCA, AWTRL,
     Cincinnati, Ohio, November, 1969.

10.   Jenkins, D. and Menar, A., "The Fate of Phosphorus in Sewage
     Treatment Processes; Part II, Mechanisms of Enhanced Phosphate
     Removal by Activated Sludge," SERL Report 68-6, Berkeley, Sanitary
     Engineering Research Laboratory,  University of California, August,
     1968,

-------
                             REFERENCES
                             (Continued)


11.  Johnson, E. L., Beeghly, J. H., and Wukasch, R. F., "Phosphorus
     Removal at Benton Harbor-St. Joseph, Michigan," Dow Chemical
     Company, Midland, Michigan.

12.  Monthly Progress Report, FWPCA Contract No. 14-12-154, "Experiments
     to Determine the Effectiveness of Phosphate Removal by Means of
     the Moving Bed Filter", September, 1969.

13.  Monthly Report for November, 1969, Joint FWPCA-DC Activities.

14.  Mulbarger, M. C., Shifflett, D. G., Murphy, M. C. and Huffman, D. D.,
     "A Full-Scale Evaluation of 'Luxury Uptake1 for Phosphorus Removal",
     (In Press).

15.  "Nutrient Removal from Digester Supernatants and Related Process
     Streams," Monthly Report No. 7, FWPCA Contract No. 14-12-414^ FMC
     Corporation, February 17, 1969.

16.  O'Farrell, T. P., Bishop, D. F., and Bennett, S. M. , "Advanced Waste
     Treatment at Washington, D. C.", presented at the 65th Annual AlChe
     Meeting, Cleveland, Ohio, May, 1969.

17.  Personal Correspondence - D. Bell, Johns-Manville Products Corporation.

18.  Personal Correspondence - R. Schuessler, Dow Chemical Company.

19.  Slechta, A. F. and Gulp, G. L., "Water Reclamation Studies at the
     South Tahoe Public Utility District," Journal Water Pollution Control
     Federation, Vol. 39, No. 5, May, 1967, p. 787.

20.  Smith, R., "Cost and Performance Estimates for Tertiary Wastewater
     Treating Processes", Internal Publication, Robert A. Taft Water Research
     Center, Cincinnati, Ohio, June, 1969.

21.  Stamberg,  J., Bishop, D., Warner, H. and Griggs, S., "Lime Precipitation
     in Wastewater,"  (In Press).

22.  Stenburg, R. L., Convery, J. J., and Swanson, C. L., "New Approaches
     to Wastewater Treatment," Journal of the Sanitary Engineering
     Division,  Proceedings  of the American Society of Civil Engineers,
     SA 6, December,  1968, p. 1121.

23.  Summary Progress Report for May, 1969, "Phosphorus Removal and
     Disposal from Municipal Wastewater", FWPCA Grant WPD 223-01-68,
     The University of Texas Medical Branch, Galveston, Texas.

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                             REFERENCES
                             (Continued)
24.   Villiers, R. V., Berg, E. L., Brunner, C. A., and Masse, A. N. ,
     "Treatment of Primary Wastewater by Lime Clarification and Granular
     Carbon", November, 1969 (In Press).

25.   Wukasch, R. F., "New Phosphate Removal Process, Water.and Wastes
     Engineering, September, 1968, p. 58.

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1
Accession Number
w
5
2

Subject Field &, Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
     Environmental Protection Agency,  Water Quality Office, Washington, D.  C,
    Title
     TREATMENT TECHNIQUES FOR  REMOVING PHOSPHORUS FROM MUNICIPAL WASTEWATERS
 10
    Author(s)
     Convery, John J.
                                16
                                    Project Designation
                                                          17010---01/70
                                     21
                                        Note
 22
    Citation
     Water Pollution Control  Research Series, EPA
 23
Descriptors (Starred First)


 *Waste Water Treatment, *Tertiary Treatment,  Biological Treatment, Chemical
 Precipitation
 25
Identifiers (Starred First)

*Nutrient  Removal
*Phosphorus  Removal
 27
Abstract

 Technology is available to remove the  nutrient  phosphorus from municipal
 wastewaters.   This paper summarizes  the  alternative methods for both biological
 and  physical-chemical treatment.  The  information should be helpful in
 providing perspective to municipal officials,  engineers and treatment plant
 operators contemplating incorporation  of nutrient control measures into
 their treatment facilities.  Process selection  will depend on specific
 wastewater characteristics, existing facilities,  required effluent quality,
 and  economic considerations.

 Processes discussed include conventional biological treatment, digester
 supernatant treatment, modified biological  treatment,  chemical addition
 in primary, secondary and tertiary stages of treatment, and moving bed
 filtration.
Abstractor
     R. L. Sffinburg
                          Institution
                           EPA, Water Qualify  Office,  Cincinnati, Ohio
 WR:102 (REV. JULY 1969)
 WRSI C
                        SEND, WITH COPY OF DOCUMENT. TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTER
                                                  U.S. DEPARTMENT OF THE INTERIOR
                                                  WASHINGTON. D. C. 20240
                                                                               * GPO: 1 970-389-930

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