WATER POLLUTION CONTROL RESEARCH SERIES • WP-2O-17
   Dissolved-Air Flotation Treatment
          of
       Combined Sewer Overflows
U.S. DEPARTMENT OF THE INTERIOR • FEDERAL WATER POLLUTION CONTROL ADMINISTRATION

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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 Federal Water
Pollution Control  Administration, in  the U. S.-  Department
of the Interior (both  inhouse  and through grants and
contracts with Federal, State, and  local agencies, re-
search institutions, and  industrial organizations).  The
exchange of such data  should contribute  toward  the long
range development  of economical,  large-scale  management
of our Nation's water  resources.

Triplicate tear-out abstract cards are placed inside the
back cover to facilitate  information  retrieval.  Space is
provided on the card for  the user's accession number and
for additional uniterms.

Water Pollution Control Research Series  will  be distributed
to requesters as supplies permit.  Requests should be sent
to the Office of Research and Development, Department of
the Interior, Federal Water Pollution  Control Administration,
Washington, D. C.   20242.

Previously issued  reports on the Storm & Combined Sewer
Pollution Control  Program:

     WP 20-11  Problems of Combined Sewer Facilities and
     Overflows - 1967

     WP 20-15  Water Pollution Aspects of Urban Runoff

     WP 20-16 "Strainer/Filter Treatment of Combined Sewer
     Overflows;

     WP 20-18  Improved Sealants  for  Infiltration Control

     WP 20-21  Selected Urban  Storm Water Abstracts

     WP 20-22  Polymers for  Sewer Flow Control

     ORD-4     Combined Sewer  Separation Using Pressure Sewers

     DAST-4    Crazed  Resin Filtration of Combined Sewer
     Overflows

     DAST-9    Sewer Infiltration Reduction by Zone Pumping

     DAST-13   Design of  a Combined Sewer Fluidic Regulator

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  DISSOLVED-AIR TREATMENT
               OF
COMBINED SEWER  OVERFLOWS
       A DEMONSTRATION PROJECT OF A PROTOTYPE

      TREATMENT PLANT DESIGNED TO TREAT WASTES

        FOUND AT A COMBINED SEWER OVERFLOW
    FEDERAL WATER POLLUTION CONTROL ADMINISTRATION

         DEPARTMENT OF THE INTERIOR
               by

         RHODES TECHNOLOGY CORPORATION
            HOUSTON, TEXAS

          CONTRACT NUMBER 14-12-11


             JANUARY 1970

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                       ABSTRACT









     A dissolved-air flotation system was evaluated for primary




treatment of combined sewer overflows.  The major pieces of




component equipment were a gyratory screen, hydrocyclones, an




air dissolving tank, and a flotation cell.






     The principal aspects investigated were:  (1) Performance




of the system during rain events and dry periods; (2) Evaluation




of individual components; (3) Capital costs and operating




costs for utilizing a flotation system for various size




combined sewage overflows; (4) The adaptability of the




system for automation and use in remote location; and (5) The




ability of the system to treat intermittent and highly variable




flows from combined sewage systems.  Some chemical aids to




flocculation were also tested.






     The system performed comparably to conventional clarifiers.




It appears dissolved-air flotation systems would be economical




for handling combined sewer overflows up to 8 MGD.  Automation




of dissolved-air flotation systems appears possible with conven-




tional control equipment.  Chemical aids to flocculation appear




to have promise that warrants further study.






     The system was unique in that all liquid flow passed




directly through the air dissolving tank with no recycle.




Domestic sewage was studied in lieu of combined sewage during




periods of no rain.






     Conclusions, recommendations, and benefit-cost relation-




ships are presented in the report.  A description of the




demonstration plant and of the drainage area served by the




flotation system are appended.






     This report was submitted in fulfillment of Contract 14-12-




11 between the Federal Water Pollution Control Administration




and Rhodes Technology Corporation, Houston, Texas.

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                       CONTENTS



Section                                             Page

Abstract

I       - Results and Conclusions
          Recommendations                              1

II      - Introduction                                 5

III     - Initiation of Investigation and Site
          Selection                                   13

IV      - Characteristics of System Components        16

V       - Air Flotation Studies and Treatment Plant
          Design                                      32

VI      - Design Details of Major Component Parts     38

VII     - Sampling and Initial Plant Modifications    43

VIII    - Testing and Evaluation                      53

IX      - Additional Testing of Chemical Aids to
          Flocculation                                67

X       - Component Parts Performance                 75

XI      - Benefit-Cost Relationships                  88

XII     - Possibilities for Automation  and Other
          Potential Applications                      95

XIII    - Acknowledgements                            106

XIV     - References and Bibliography                 108

XV      - Appendices

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                        FIGURES
Figure                                                 Page

   1     Schematic Diagrams of Various Methods of
         Dissolving Air in Waste Water                  22

   2     Schematic Diagram of an Hydrocyclone           26

   3     Drum and Traveling Screens                     29

   4     Circular Vibrating Screen                      30

   5     Air Dissolving Tank                            33

   6     Flow Diagram - Combined Sewer Effluent
         Treatment Plant                                36

   6a    Demonstration Pilot Plant                      39

   7     Pressure Control Valves                        41

   8     Flotation Tank                                 42

   9     Sample Point Diagram - Demonstration Pilot
         Plant                                          44

  10     Distribution Box at the Fort Smith "P" Street
         Pollution Control Facility                     48

  11     Modification of Distribution Box at Fort Smith
         "P" Street Pollution Control Facility          49

  12     Detail of Flotation Cell Showing the Baffle
         Plate Installed to Trap Large Air Bubbles      50

  13     Inlet Header as Built; Suggested Design for
         Inlet Header                                   51

  14     Relationship Between Suspended Solids Removal
         Efficiency and Pressure Differential           81

  15     Location and Size of Holes Cut in Exit Weir
         of One Cell of Flotation Tank                  86

  16     Benefit-Cost Ratios                            92

  17     Automated Standby Combined Stormwater -
         Domestic Sewage Treatment Plant                97
                           ii

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                        TABLES


Table                                                   Page

  I    Air Dissolving Tank, Air Flotation Tank           24

  2    Percent Removal of Sewage Components When
       Different Equipment Combinations Were Used
       (No Chemical Flocculants)                         55

  3    Percent Removal of the Various Components When
       Different Chemical Treatments Were Used.  All
       Mechanical Separatory Equipment Was On Stream     59

  4    Percent Removals of the Various Components
       During Rain Events.  All Mechanical Separatory
       Equipment Was On Stream                           62

  5    Summary of Removal Rates                          64

  6    Comparison of Sewage Strengths                    65

  7    Additional Chemical Tests                         68

  8    Additional Chemical Tests                         69

  9    Additional Chemical Tests                         70

 10    Chemical Treatment Costs                          72

 11    Oil Removal Test                                  73

 12    Supplementary Data On Pressure Drop Across
       Cyclones                                          78

 13    Effect of Air Feed Rate and Pressure Differ-
       ential On Total Suspended Solids Removal, Percent 80

 14    Effect of Flow Rate On Suspended Solids Removal   86

 15    Effective Flotation Depth                         87

 16    Costs and Benefits, Air Flotation and Conven-
       tional Clarifiers                                 89

 17    Physical Sizes and Land Areas Required by
       Conventional Clarifiers and Dissolved Air
       Flotation Units                                   93
                          iii

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       SECTION 1






RESULTS AND CONCLUSIONS




    RECOMMENDATIONS

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                RESULTS AND CONCLUSIONS






     1)  The dissolved-air flotation system removed suspended




solids from combined sewage with 12 minutes retention  time  as




effectively as conventional clarifiers with 4 hours reten-




tion time.  During rain events and without chemical aids, the




system removed an average of 69 percent of the  suspended solids




passing a gyratory screen installed to removed  gross particles.




Injection of alum and a polyelectrolyte into  the  system in-




creased the removal rate to an average of 84  percent.  Alum  alone




was ineffective.  Without chemical aids, BOD  reduction averaged




26 percent.  When chemical flocculating aids  were injected,  BOD




reduction increased to an average of 42 percent.






     2)  Efficiency during dry weather, was essentially the




same as during rain periods.






     3)  Automation of dissolved-air flotation  systems




appears feasible for the treatment of  intermittent, variable,




and high instantaneous flow rates normally encountered with




combined sewage overflow.  Surge  tanks or retention basins




are unnecessary when dissolved-air flotation  is used  as a




treatment for combined sewer overflows, provided there are




approximately 2 minutes storage time available  in the




sewer system.

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     4)  Total annual costs for dissolved-air flotation systems




are less than costs for conventional clarifiers for flows up




to 8 million gallons per day.  For treatment of storm water




flows more than 8 million gallons per day, conventional clari-




fiers show lower total annual costs.  As capacities increase,




operation and maintenance costs become very significant in



the dissolved air process.  However, dissolved-air flotation




units require only one-tenth as much land area as conventional




clarifiers.






     5)  The foam collected contained 5 to 7 percent dried




solids of 70 percent volatility.   Conventional sludge hand-




ling techniques  may be used to dispose of the foam, except




sludge thickeners can probably be eliminated.






     6)  Evaluations of individual components show the gyratory




screen, the full flow air dissolving tank and the flotation




cell were very  effective.   Cover against wind and rain was




essential to full efficiency of the flotation cell.  The



hydrocyclones used could not be evaluated fully because of




periodic plugging.   However,  the cyclones did remove the kind




of dense inorganic materials which overload sludge digesters or




form clinkers during sludge incineration.

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                    RECOMMENDATIONS









     1)  Dissolved-air flotation of combined sewer overflows




should be considered as an alternate to conventional treat-




ment methods.







     2)  Additional research is necessary to fully evaluate




hydrocyclones.   The solids collection pots and pneumatically




operated dump valves should be eliminated from the cyclones




and replaced by adjustable apex valves allowing continuous




cyclone underflow.







     3)  Consideration should be given the use of screw




conveyors to move foam from the foam collection troughs.  This




will permit a drier foam to be produced.






     4)  Alternate screening mechanisms should be considered.




In future applications of the present dissolved-air flotation




design, a comprehensive study should be made of the




characteristics of suspended solids for each application.






     5)  Pilot  plant studies of chemical aids  to flocculation




are recommended to determine costs of producing waters of




secondary treatment plant quality.






     6)  The efficiency of a total treatment unit consisting




of the dissolved-air flotation system for both primary and final




clarification of trickling filter and activated sludge effluents




and combinations of the following secondary and tertiary treating




systems should  be investigated:

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         a.  Rapid sand filtration.




         b.  High rate trickling filters.




         c.  Activated carbon filtration.




         d.  Chlorination or hypochlorination.






     7)  Additional research and pilot plant work is




recommended to study the applicability of dissolved-air




flotation to the treatment of various industrial wastes

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                  SECTION  II






                 INTRODUCTION






THE COMBINED SANITARY AND  STORM  SEWER OVERFLOW






         PROBLEM IN THE UNITED STATES






  PROPOSED SOLUTIONS TO THE OVERFLOW PROBLEM

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                     INTRODUCTION




    THE COMBINED SANITARY AND STORM SEWER OVERFLOW




             PROBLEM IN THE UNITED STATES






     The flooding of basements,  low lying buildings,  and  land




by combined sewage causes immeasurable direct  damage  and




inconvenience to an estimated 36 million people  in  over  1300




cities and communities in the United  States.   Collector  sewers




which are too small for the large flows from  storm  water  run-




off are the major cause of the direct damage.   The  costs  of




this direct damage are spread indirectly in  the  form  of  higher




costs for goods and services to  the entire U.  S.  population  (1).






     Reduced water quality is one example of  indirect damage




caused by storm water run-off and combined sewer  overflows.




Many treatment plants have insufficient capacity  to remove  the




silt and organic matter flushed  from  sewers  by the  surge  of




storm waters.  It is not uncommon, after an  extended  dry  spell,




for treatment plant operating personnel to bypass the first




waters received after the start  of a  rainfall to  avoid a buildup




of grit and silt in the clarifiers.   Receiving waters also




suffer quality reduction when improperly maintained or




inoperative flow regulators permit storm waters to  overflow




directly to receiving waters, bypassing all  treatment facilities.






     Because of these and many similar  situations,  there is




great need for low-cost and reliable  facilities to  handle

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combined sewage overflows.






     The concept of  the  combined sanitary and  storm  system  is




several thousand years old  (2).  Originally, sewers  were  used




for storm drainage only.  Domestic wastes were  the responsi-




bility of the individual householder and were  disposed  of in




dry wells, cesspools, and septic tanks.  It became necessary




to dump domestic wastes into the streets to be  washed  into




storm drains when rains occurred.  The practice spread.   With




increasing urban populations and the advent of  industrialization,




true combined sewer systems became a fact through  the  piecemeal




addition of open channels draining into  the storm  sewers.




Eventually, closed conduits and pipes were added to  the  system.




In many instances the old closed facilities still  exist  and




are in service,  but,  because they were designed for  small




drainage areas and have a limited capacity, they are over-




burdened even in dry  weather.  During storm periods  the




combined waste waters cause local flooding.







     Each of these old sewers has its own outfall  at a  nearby




river or stream.  The result is a multitude of  outfalls  and




evil-smelling areas along water courses.  Interceptors  have




been constructed to alleviate the situation, but overflows




still course through the outfalls.  More than  400  such  outlets




are still to be found in Cleveland, for  example (3).






     The total number of cities having combined sewers  has




decreased in recent years.  The reduction has

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been accomplished by building  new  interceptors  to  separate the




wastes and by rebuilding  the old sewer  systems.  Most new




construction involves separate sewers,  but  occasionally the




separate sewers in new suburbs and  residential  areas are




connected to the interceptors  of a  combined system in older




sections of the communities, compounding  the existing over-




flow problems.  Some combined  facilities  are still being con-




structed in cities which  already have  combined  sewers (4).






     Haphazard additions  to sewer  systems have  led to numerous




overflow and treatment problems.   Additionally,  lax enforce-




ment of sewer regulations  and  restrictions  plus  ambiguous and




conflicting interjurisdictional construction codes have led




to large networks of sewer lines feeding  to central treatment




facilities.  For example,  Cleveland,  Ohio,  serves  32 govern-




mental units outside its  city  limits;  many  of these are




without any form of municipal  organization  (1).






     These problems have  not gone  unrecognized,  and in some




areas sanitary districts  or authorities with broad powers and




adequate financial structure have  been established to help




combat and correct these  problems.






     The American Public  Works Association  in its  report for




the FWP.CA, "Problems of Combined  Sewer Facilities  and Overflows'




(1), states that over 50  percent  of the jurisdictions inter-




viewed have problems due  to infiltration of ground waters.




The surcharge of sewers due to infiltration of  ground waters

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is a problem common to both combined and separate sewer systems




The separate sewer systems found in much of the Southwestern




United States are particularly susceptible to infiltration of



ground waters during both wet and dry weather.






     Dry weather infiltration occurs when sewers are below the




water table.  Infiltration during dry weather is often unre-



cognized until attempts are made to relate water utility




service pumping output to waste water treatment plant flow



records.  Dry weather infiltration waters together with the




existing flow of sanitary wastes often approach the capacity




of the treatment facilities, leaving little or no capacity



for rain waters.  The infiltration of ground water into the




sewer systems during rain events causes many of the same



problems as occur in combined sewers:  Namely, flooding of




basements,  overloading of treatment facilities, and dis-




charging of wastes through overflows.






     The magnitude of the infiltration problem is illustrated




by an unsigned article in "American City" (5).  The author



discusses the methods used by the city of North Miami, Florida,




to dispose  of daily treatment plant effluents containing up to




75 tons of  salt from salt water constantly infiltrating the



municipal sewer system.






    Among the methods used to control infiltration are better




supervision of the installation of the facilities and the



sealing of  existing facilities against infiltration.
                              8

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                     PROPOSED SOLUTIONS




                   TO THE OVERFLOW PROBLEM









     The cost of separating the combined sewers in the



United States has been estimated up to $30 billion plus an




additional $18 billion for plumbing service connections to




private property (1).  Other sources list the cost at $10




million per square mile or about $1,000 per family served (3).




The cost in time and inconvenience to the populations involved




is beyond estimation; the need to alter roof and basement




drains alone would entail a tremendous public relations effort




and would provide fertile ground for countless property damage




suits.  Peters and Troemper (6) report on the difficulties




encountered by the Springfield, Illinois, Sanitary District




in removing or attempting to remove the rainwater downspouts




from residences.  Several "questionnaires, letters, and inspec-




tions were necessary to approach 100 percent compliance with




a long-existing regulation concerning the connection of




downspouts to sanitary sewers.  The authors report that




compliance with the regulation eliminated flooding of basements




due to surcharge of sanitary sewers during rainstorms.






     Many alternatives to complete separation are available.




Although each situation presents its own problems, there are




enough similarities that solutions can be categorized.  The




Chief of the Storm and Combined Sewer Pollution Control Branch,

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Federal Water Pollution Control Administration of the U. S.




Department of Interior, in a speech presented at the Spring




1968 Meeting of the New England Water Pollution Control




Association, discussed three basic approaches that can be




utilized to solve combined sewage or storm water pollution




problems:




     1)  Control.




     2)  Treatment.




     3)  Combinations of control and treatment.






     It is not the purpose or intent of this report to treat




or discuss all the details and ramifications of each categorical




solution or even to  list all the possible solutions.  Some of.




the more publicized  solutions are listed for illustrative




purposes.






     The storage of  storm induced overflows in limestone tunnels




deep under Chicago has been mentioned; the sale of excavated




limestone would help to defray some of the construction costs (7).






     Two large collapsible rubberized storage tanks, each of 100,00




gallons capacity, to be anchored in the Anacostia River to store




overflows during heavy rainfalls are being constructed and installe




in Washington, D. C.  This is not intended to provide complete




relief to the overflow problem; need for ten tanks is estimated.




After the storm ends, stored waste waters will be pumped to




currently available  treatment facilities.  Similar projects are in
                            10

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 process at  Cambridge, Maryland,  and  Sandusky,  Ohio.




     Chemical additives for waste water have been developed




which reportedly increase the flow in sewer pipes up to 2-1/2




times, thereby achieving peak-flow relief without new




construction (8).  A novel plastic sealant to eliminate




excessive  sewer flows due to infiltration of ground waters




has been reported by the same source.






     Chlorination and hypochlorination of storm waters are




being investigated by the city of New Orleans.  Although the




sewers in  New Orleans are separated, storm waters pumped into




Lake Pontchartrain carry a tremendous load, necessitating the




closing of some public beaches after major rainfalls.  The




City of Boston is studying the use of retention basins for




storage and sedimentation in conjunction with hypochlorination




for the treatment of storm overflows from its combined sewer




system.






    Some treatment or control methods have been in use for




some time  in various communities throughout the United States




and abroad.






     One current test, supported by FWPCA, has been described




as follows.






     "One  of the Dallas grants in the amount of $828,750, or




75 percent of the total eligible project costs, funds a project
                             11

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which consists of the design, construction, and evaluation of




a facility to treat overflows from sewers carrying a mixture




of domestic waste water plus storm water infiltration.




Physical features include a diversion structure, a pumping




station, flocculation and sedimentation basins, chemical feed




facilities, and a conveyance system for transporting waste




lime sludge from a municipal water plant to the storm water




treatment facility.   Unique features of this project include




the demonstration of tube-type clarifiers and the evaluation




of the utilization of waste chemicals from a water-softening




plant to enhance settling in the waste water sedimentation




unit" (9).
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        SECTION III






INITIATION OF INVESTIGATION






    AND SITE SELECTION

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              INITIATION OF INVESTIGATION




                  AND SITE SELECTION









     In mid-1966, the Federal Water Pollution Control




Administration advertised in The Commerce Business Daily for




concepts and new approaches to the solution of the problems




of combined sewer facilities.  Engineers of Rhodes Technology




Corporation, Houston, Texas, were convinced that the problems




involved in the treatment of sanitary and combined sewage




were not extremely different from the problems involved in the




treatment of waste water in oil fields and that the techniques




that had been used to clarify waste water in the oil fields




would be directly applicable to the treatment of sewage.




Considerable experience has been gained over the past 15 to




20 years in the use and operation of dissolved-air flotation




units to remove oil and suspended solids from oil field




waste water.  Additionally, considerable experience has been




gained in the use of hydraulic cyclones or hydrocyclones for




the removal of heavy materials such as silt, sand, and clay




from water.






     A proposal was submitted to FWPCA suggesting the linking




of these pieces of equipment into a single treatment unit of




extremely short retention time (about 10 minutes).






     The Federal Water Pollution Control Administration awarded
                           13

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the contract for this study to investigate the concept of




using hydrocyclones, a dissolved-air flotation unit, a low




liquid retention time, and screens as well.  Screens were




thought necessary so that particle size entering cyclones




could be limited.  Comminutors were not included because




sludge digestion was not a part of this study.






     Included in the contract was a provision calling for




the selection of a site for the dissolved-air flotation unit.




Items to be considered in the site selection included the




availability of the following items :




     1)  Land for the erection of the dissolved-air flotation




         plant.




     2)  storm waters during storm events.




     3)  Domestic waste to be used in lieu of storm water in




         dry weather periods.




     4)  Fresh water for the dilution of domestic wastes,




         should the need arise.




     5)  Electric power.




     6)  A laboratory for the analysis of  the influent and




         effluent waste streams.




     7) :  The cooperation of the necessary  municipal officials




         and employees.




     Several of the sites inspected included Kansas City and




St. Louis, Missouri; Oklahoma City, Norman,and Stillwater,




Oklahoma; and Fort Smith, Arkansas.  Each  of the sites offered




many possibilities for the successful completion of the project,
                            14

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Fort Smith, Arkansas,  was selected because it was the only




site at which all of the desired items were available.






     This report covers results of bench scale tests, design




of a dissolved-air flotation plant, and operation of the




plant from October 1967 to December 1968.
                             15

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             SECTION IV






CHARACTERISTICS OF SYSTEM COMPONENTS

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         CHARACTERISTICS OF SYSTEM COMPONENTS






                Dissolved-Air Flotation






    Air flotation systems have been used for many years in




the mining industry to concentrate low grade ores by frothing.




Hanson and Gotaas (10) claim the first froth process was




patented in 1860 by Hanes.  The froth process does not use




dissolved air;  air is injected by several means.  In recent




years the trend has apparently been to use air injected




through the shaft of an impeller.  The impeller breaks the




air stream into millions of bubbles creating a froth or foam




which rises to  the surface, floating the ore or gangue,




whichever is lighter.  In most cases frothing is aided by




the use of chemicals such as alcohols, resins, or soaps.






    The flotation method of separating ores from overburden




material is discussed in much research literature.  Gaudin




(11) mentions that gas flotation was first recognized as early




as 1901.  Fromet obtained a British patent on the use of gas




bubbles to remove sulphite minerals from ores in 1903.  The




vacuum process  is mentioned by one author as being patented




in 1907.  Norris (12) was issued a patent in 1907 in which




a pressurized slurry of water and ore was used.  Elmore




(13) was granted an English patent in 1905 for  the vacuum




separation of ores.  Previous systems, according to Elmore,




used frothing aids such as oil,  tars, and soaps.
                            16

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Elmore claimed his system would reduce the amount of chemical




aids needed.  Another English patent was awarded for the use




of a pressurized flotation system in 1906 to Suhman,




Kirkpatrick-Picard, and Ballot .  The patent was also granted




in the United States(14).






     All. dissolved air. systems involve injection of air into




a liquid/under pressure followed by transfer of the liquid to




a cell where the air leaves solution in  the form of small




bubbles.






     D'Arcy (15) claims the modern dissolved-air flotation




system was invented in Norway  by Sveen and Pederson.  No date




for the invention is given.  The Sveen-Pederson process is




widely used in the paper and pulp industry for the clarification




of "white'water".  The dissolved-air flotation system is




widely used in.industry, as indicated by many references




throughout the:literature to its various applications.  Specific




applications include the removal of oil  and suspended matter




from oil field wastes;  The use of dissolved-air flotation




systems is discussed in several papers relating to the separation




of oils and fats in the soap, and .detergent industry.  Dissolved-




air flotation systems are also used by the food processing,




meat packing, and slaughterhouse industries.  Several steel




mills,report the use of dissolved-air flotation for the removal




of grease and oil from water,  while both the Santa Fe and the




Union Pacific railroads report the use of dissolved-air




flotation to clean wash water. Chrysler  Corporation reports
                             17

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using the dissolved-air flotation system to clean process


water (16).




     The operator of a 400-gallon-per-minute dissolved-air


flotation system installed at the Indiana Farm Bureau


Cooperative  Association Refinery near Mount Vernon, Indiana,


claims a BOD reduction of 78 percent and a suspended solids


reduction of 93 percent when waste waters with pH 9


are fed through the system.  In addition, he reports a 90


percent removal of oil (17).




     An extensive literature search reveals a considerable
                                                         •>

amount of data relating to the design and use of flotation


cells.  Howe (18), in a mathematical derivation of flotation


cell design, recommends that considerable experimentation
                                       /•

with each different waste precede the use of his equations in


determining  the exact criteria for flotation cells.  He  further


states that  particle size and density, liquid viscosity, and


liquid density are factors to be considered in designing tank


depth, overflow rate, and retention time.  He goes on to state


that bubbles released in the liquid are less than 130 microns


in diameter, smaller than the bubble size in the froth system.




     A comprehensive discussion by D'Arcy (15) of the use of


dissolved-air flotation systems to separate oil from waste


waters includes six important general considerations:


     1)  Dissolving a maximum amount of air in the influent.


     2)  Elimination of all entrained air as the release of
                           18

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         entrained air in the flotation system introduces




         turbulence and short circuiting.




     3)  Proper hydrodynamic design of the entire flotation




         system, especially the flotation chamber.




     4)  Selection of proper coagulant and floe-forming




         chemicals if they are required--always bearing in




         mind that the most economical as well as the most




         efficient chemicals should be used.




     5)  Continuous mechanical removal of oil or floe on the




         surface of the water in the flotation chamber.




     6)  Design of the entire system to produce a unit which




         will operate automatically under a wide range of




         conditions and which requres the minimum amount of




         trained personnel for its operation.






     The equipment discussed by D'Arcy is operated by regular




oil field personnel and seldom requires more than 3 man-




hours per day, this time being used for mixing chemicals and




lubrication of equipment.   Chemical costs are in the neigh-




borhood of $2 per thousand barrels ($48/million gallons) of




waste treated and have been as low as 80 cents per thousand




barrels ($19/million gallons) when alum or activated silica




are used for treatment.






     The fundamental principles of dissolved-air flotation




as applied to industrial wastes were discussed by Vrablic at




the Fourteenth Annual Industrial Waste Conference at Purdue




University (19).  Among other things, Vrablic hints that
                             19

-------
advantage should taken of fact that oxygen is  twice




as soluble in water as nitrogen.  He further claims




that the flotation system makes use of three funda-




mental processes:




     1)  Adsorption of air bubbles on the solids.




     2)  Trapping of air bubbles by the solids.




     3)  Adhesion of air bubbles on the solids.




Vrablic states that hydrophobic solids will float much more




easily than will hydrophillic ones.  He recommends an air  to




solids ratio of 0.06 (Ib of air/lb of dry solids).






     Eckenfelder, et al, found a ratio of 0.02 most  favorable  (20)




These researchers report the use of a laboratory scale model




to treat domestic sewage.  The scale model consisted of  a




stell pressure tank which was filled with waste activiated




sludge, pressurized, and then shaken.  The liquid was then




released into a Lucite cylinder for decompression and foaming;




periods of foam formation took up to 20 minutes.  They report




excellent suspended solids removal and further indicate  that




turbulence must be controlled to reduce the shearing of  fine




floe.






     Results varying from between 20 and 82 percent  removal of




unemulsified oil are discussed by Rohlich (21).  A 75 gallon-




per-minute flow of waste water was directed through  an air




flotation unit using a retention time of 12 minutes.  The  tank




had a surface area of 34 square feet and was 3-1/2 feet  deep.
                           20

-------
The air dissolving tank had a capacity of 150 gallons with a




resulting retention time of 2 minutes.






     Rohlich feels that a retention time of 2 minutes is




necessary to insure saturation of air in the liquid stream.




Air was dissolved in the waste stream at a pressure of  50  to




60 pounds per square inch.  The three types of pressurization




shown in Figure 1 were attempted.  These include  the diversion




of part of the influent stream through the pressure tank,




recirculation and pressurization of the recycled  waste  water,




and total pressurization with air injected through a venturi




device.  The experiments relating to  total pressurization  used




a flow rate of 50 gallons per minute.






     Prather (22) discusses the reduction in chemical oxygen




demand (COD) in an oil refinery waste using dissolved-air




flotation.   In the waste discussed, the COD was due primarily




to suspended solids.   The dissolved-air flotation system  in




this application was  originally designed to remove oil  and




suspended material.   In order to achieve a significant  removal




of COD and suspended  solids, pH adjustments were  necessary.




Values of pH between 8 and 9 are reported.






     Hopper and McGowan (23) report the use of frothing to




purify surface waters in a 1950 experiment using  34 different




surface waters as test media.  Nontoxic quaternary ammonium




compounds were used in an attempt to  reduce the bacterial




content of drinking water.  Bacterial reductions  up to
                            21

-------
     SCHEMATIC  DIAGRAMS  OF VARIOUS METHODS OF
           DISSOLVING AIR IN WASTE WATER

                                        AIR  FLOTATION
                                           TANK

1
t
^ ( 1 \ /r-ir-tr-
i


                  PUMP
                                    AIR
                                 COMPRESSOR
(Q) PI VERSION OF PART OF FLOW THROUGH PRESSURE TANK
                    AIR  FLOTATION
                        TANK
      PRESSURE TANK
                             PUMP
                        AIR
                      COMPRESSOR

     (b) DISSOLVING AIR IN RECYCLED WASTE WATER
                         AIR
                        INLET
                         I
AIR FLOTATION
    TANK
          PUMP
                       VENTURI
                         TUBE
    (c) INJECTION OF AIR THROUGH A VENTURI  DEVICE
                        FIGURE 1


                          22

-------
99 percent (plate count method) were reported, and




95 percent of suspended solids were removed.  Cost of




operating the system is reported as 5 cents per thousand




gallons.






     Air bubbles less than 100 microns in diameter were used




for sludge thickening and total solids removal in several units




reported by Katz and Geinapolos (24).  The units being studied




used a 50 percent recycle rate in which air was introduced at




the rate of 1 cubic foot of air per 100 gallons of recycle




water.  The authors indicate dry solids loading rates of 10




to 20 pounds per square foot per day for activated sludge and




55 pounds per square foot per day for primary wastes.  The




units varied from 7 to 12 feet in depth.  Katz suggests that




the flotation system includes several types of flotation and




that hindered flotation was one of the phynomena encountered.




Sludge was thickened to a •consistency of 3 to 4 percent




solids.






     Bubbles forming in sanitary sewage have terminal velocities




of 0.14 inches per second.  This value is the basis of a




design discussed by Masterson and Pratt (25) .  They suggest




that free air evolves in the air dissolving tank when over 60




percent of saturation is reached.  However, they also state,




"The greater the amount of air dissolved, the greater will be




the (flotation) effect".
                           23

-------
     A summary of the pertinent suggested values reported in




the design of dissolved-air flotation systems are given in




Table 1 below:








                         TABLE 1




     Air Dissolving Tank;




     Pressure -                50 to 60 psig




     Retention time -          2 minutes




     Air feed rate -           1 cu ft/100 gal waste




     Recycle rate -            50 percent




     Air to dry solids ratio - 0.02 to 0.06 Ib air/lb solids








     Air Flotation Tank;




     Dry solids loading rate - 55 Ib/sq ft/day




     Surface loading rate--    2.0 to 2.5 gal/sq ft/min




     Depth -                   3.5 to 12 ft






                   Hydraulic Cyclones




     Storm water overflows and combined sewer systems receive




a variety of dense materials; it is almost impossible to control




the influx and arrival of these materials at treatment plants.




In order to minimize the accumulation of the resulting sediments




on the bottom of flotation tanks, Rhodes Corporation engineers,




on the basis "of their oil field experience, suggested the use




of hydrocyclones for the removal of the dense material.
                            24

-------
     The pneumatic cyclone has long been used in the lumber




and furniture industries for removing wood chips and sawdust




from air streams.  The hydraulic cyclone, or hydrocyclone,




uses the same principle as the pneumatic cyclone.  A comment




by Pryor indicates that hydrocyclones were first used in the




petroleum industry in 1939.  Figure 2 indicates the general




configuration of a cyclone in which an inverted cone has a




cylinder attached to its wide end.  Waste water is injected




tangentially into the cylinder and is forced to travel in




a spiral pattern through a shorter and shorter radius toward




the narrow end.  Centrifugal force causes the heavier particles




to move to the outer edge of the stream.  Upon approaching




the narrow end of the cone, waste water escapes through a




tube called a vortex finder running up the center of the




cone.  Solid materials which have been forced to the outside




of the waste stream fall to the bottom of the cone, are




collected, and disposed of.






     Leniger states, "When dealing with suspensions of very




fine particles, an obvious measure to be adopted consists




of accelerating sedimentation by centrifugal force.  There




has been a choice between hydrocyclones in which a rotation




of the suspension is produced by introducing it  tangentially




into a stationary apparatus and centrifuges  (here termed




clarifiers), in which the liquid is caused to rotate by




revolving a drum.  For hydraulic classification a  so-called
                             25

-------
                             APEX VALVE
               SOLIDS OUTLET
SCHEMATIC DIAGRAM OF AN  HYDROCYCLONE
              FIGURE  2
                     26

-------
hydrocyclone  is not used with  much success.   Hydro-




cyclones have the  advantage of  simplicity and flexibility




so that  the results  may be modified  by altering  various




operating  conditions.   As opposed  to other types of




apparatus,  they are  better for  classifying than for




clarifying.   The reason is that the   high shearing stresses




in the hydrocyclone promote the suspension of particles and




oppose flocculation.  A disadvantage lies in the fact that




both the fine and coarse fractions are obtained in suspensions




of relatively high dilution.  Furthermore they only operate




well in a medium of low viscosity" (27).






     There is abundant literature on the theory and design of




hydrocyclones.   Broer (28)  discusses efficiency as judged by




the separating  capacity and power consumption of the hydro-




cyclone, and Van der Kolk (29) investigates the ability of




cyclones in series arrangements to protect expensive devices




and to collect  several grades of bulk material.  Van der Kolk




illustrates his discussion with several diagrams showing




different schemes for connecting cyclones in series.   He




concludes his article with a discussion of the advantages




of the various  ways of linking the cyclones.






    A major manufacturer (30) of hydrocyclones uses an adver-




tising brochure for a very enlightening discussion on the use




of hydrocyclones as classifiers.   Among other comments, the




manufacturer lists four major cyclone applications.
                             27

-------
     1)   Classification  or  sizing  of  particles.   Cyclones




         separate  particles according to  their  relative  mass




         rather  than  strictly  by particle size.   However,




         the  generally  accepted  range of  cyclone operation




         is from 35 mesh to 5  microns.




     2)   Degritting water or water suspensions  of fine solids.




     3)   Desliming operations.




     4)   Closed  circuit  grinding  classification.








                           Screens






     The apex valve of  the  hydrocyclone is generally of much




smaller  diameter than the inlet,  and large particles which




enter the cyclone  can sometimes  clog the apex valve.  To




prevent  this  plugging,  the  manufacturer suggested screening




the waste water  entering the cyclone.  Of particular hazard




are materials such as sticks,  pencils, etc., which can bridge




the narrow apex  valve.   Once bridgedt  the valve easily becomes




further  clogged  with  other  materials and, within a short time,




the cyclone must be  removed from the system, dismantled,




and unplugged.






     The commonly-used bar screen is of no value in this




application;  turbulence can cause sticks to twist in  such a




way as to pass through the screen.   Screens which are available




for the  operation envisioned include drum screens and endless




belts illustrated in  Figures 3a and  3b and vibrating  screens




illustrated in Figure 4.   The vibrating screen  apparatus
                             28

-------
            SCREENINGS
            DISCHARGE
            TROUGH
INFLUENT   —-<
SPRAY PIPES
    SCREEN COVERED
   'DRUM
                (a) DRUM SCREEN
             i  EFFLUENT
               (b) TRAVELING  SCREEN


                      FIGURE 3
                          29

-------
          FEED
 SOLIDS
OUTLET
                                 WASTE  WATER
                                   OUTLET
                 FIGURE 4
                     30

-------
has several advantages:




     1)  The screen is easily removed from the apparatus for



         replacement and changing of mesh size.




     2)  There is only one moving part.




     3)  The screen is self cleaning.



The vibratory screen is found in a variety of applications,




including the removal of stones, rocks, and coarse material in



mining operations; the removal of feathers in turkey and chicken




processing plants; the removal of water from vegetables in the



frozen food industry; and the removal of wastes in the vegetable



and fruit canning industries.
                            31

-------
       SECTION V






 AIR FLOTATION STUDIES






          AND






TREATMENT PLANT DESIGN

-------
      AIR FLOTATION STUDIES AND TREATMENT PLANT DESIGN








     Items to be investigated before the dissolved-air




flotation system could be designed included methods of




dissolving air in the waste stream and design of the air




flotation tank.






     Several methods are often used for dissolving a gas in




a liquid.  Many  of the conventional methods suggested in The




Chemical Engineers' Handbook (31) were discarded because of




the possibility  of trapping suspended particles in the




dissolving unit.  Two designs were selected for trial.  One




design included  the use of Raschig rings as a packing material,




The other design is illustrated in Figure 5 and consists of




a cylindrical outer tank with a stand pipe in the  center of




the tank.  Air and the incoming waste stream enter the




bottom of the inner stand pipe; air dissovles in the waste




liquid as the air and waste liquid rise through the stand pipe,




Additional air is dissolved as the waste liquid overflows




the stand pipe and falls through the air gap at the top of




the outer cylinder.  Because oxygen is more soluble than




nitrogen, the unit was designed for a constant  flow of air




through the air dissolving tank.  Air deficient in oxygen




but rich with nitrogen was constantly being replaced with




oxygen-rich air for better dissolving efficiency.
                             32

-------
INFLUENT
            5
            o




            o

            en
            UJ
            o


            o
                             t
                               VENT VALVE
                                     , t
                                  LJJ
                                                    EFFLUENT


                                                    PRESS COh

                                                          \AU
              AIR  DISSOLVING  TANK
                     FIGURE 5
                           33

-------
     The design  indicated in Figure 5 was selected after trial

     because:

     1)   The Raschig rings in the alternate design collected

         waste  solids.

     2)   Air dissolving efficiency in the alternate design was

         low,  as evidenced by a lack of bubbles in the flotation

         tank.

     3)   The tank used  in the selected design had few places

         where  solids could become lodged.

     4)   There  were abundant bubbles produced in the flotation

         tank when the  selected design was tested.


     The waste  particles entering the flotation cell have two

major velocity  components.  A horizontal component is imparted

to the particle  by the  hydraulic flow; a vertical component

results  from the buoyant effect of the air bubbles.  Therefore,

the critical dimensions of the flotation cell are obviously

depth and length.


     A modified  version of Stokes Law:

          v =    g ( P1 - Pd ) D2

                      18  u

          where

                 v = terminal velocity of particle
                 g = acceleration of gravity
                P^ = liquid density
                Pj =* particle density
                 D = particle diameter
                 u = liquid viscosity
                              34

-------
indicates that the vertical velocity is a function of particle




size and particle density.  If the vertical travel of the




particle could be decreased, the length of the air flotation




tank could also be decreased.






     A model of the air flotation tank was constructed using




a rectangular design 14 inches deep by 2 feet wide by 5 feet




long.  The tank was constructed in such a way that the liquid




depth, the length of the tank, and the depth of the influent




stream could be varied.  Flow rates with turndown ratios of 15




to 1 were provided.   Optimum suspended solids removal rates




occurred for surface loading rates in the neighborhood of 1.5




gallons per square foot of surface per minute.  The foam




formed was quite easily removed by means of a scraper and




appeared to be stable.






     On the basis  of data obtained from the models of the air




flotation tank and air  dissolving tank, the demonstration




treatment plant (Figure 6) was designed.






     The demonstration  plant provided primary treatment only.




No solids treatment  facilities were included.  Combined waste-




waters first flow  over  screens to remove the gross debris expected




from storm run-offs.  Grit and organic matter are removed by




hydrocyclones.  The  liquid overflow from the cyclones then




passes through a pressurized air dissolving- tank and on to the




air flotation cells.  In the cells dissolved air comes out of




the solution and forms  tiny bubbles around the suspended solids
                           35

-------
      INFLUENT
SOLIDS TO
                    1
                                           P-l
                GYRATORY
                 SCREEN
                                    TANK
DISPOSAL
  CLARIFIED WATER
    KEY

P-l   ...PUMP I
C-l	PRIMARY CYCLONE
C-21
C-3|	SECONDARY CYCLONES
CA)
PCV.	PRESSURE  CONTOL VALVE
T\  i
                                         FLOTATION
                                           CELL
                                                                                        AIR
                                                                                    DISSOLVING
                                                                                       TANK
                                                                         PCV
                                      FLOW DIAGRAM
                         COMBINED  SEWER  EFFLUENT TREATMENT  PLANT
                                                                                 f
                                                                                 AIR
                                        FIGURE 6

-------
or immiscible liquid microparticles, which act as nuclei.  The




bubbler-particles float to the surface and form thin mats which




are removed by scrapers.  Dense materials which escape removal




in the cyclones sink to the bottom of the flotation cell and




are scraped into a collection trough.  Effluent waters may




be further treated or discharged into a receiving stream or river;




the solids collected may be passed to conventional sludge




equipment.
                            37

-------
     SECTION VI
   DESIGN DETAILS
         OF
MAJOR COMPONENT PARTS

-------
                    DESIGN DETAILS




                          OF




                 MAJOR COMPONENT PARTS








     Figure 6a is a detailed diagram of the dissolved-air




flotation system as contructed at Fort Smith, Arkansas.




Incoming waste water was screened by a 48-inch gyratory screen,




and the screened waste water was then dumped into Tank 1.  The




liquid level was controlled by a flow control valve at the




outlet from the Fort Smith sewage distribution box.






     A multi-stage vertical turbine pump removed waste water




from Tank 1 and forced it through two banks of hydrocyclones




at a design rate of 350 GPM.  The primary cyclone was 12




inches in diameter and was sized to remove particles as small




as 50 microns in diameter.  Partially degritted water from




the primary cyclone was directed to a bank of three secondary




cyclones operated in parallel.  The secondary cyclones were




10 inches in diameter and were each capable of handling




150 GPM of flow.  The secondary cyclones were designed to




remove particles as small as 25 microns in diameter.  The




design pressure drop across the secondary cyclones was




approximately 20 pounds per square inch.






     The two-stage cyclone design was selected for two reasons:




     1)  The primary cyclone was included to remove the larger




         dense particles, because it was feared that these
                           38

-------
FROM MAIN
INLET
JUNCTION BOX
     ...PUMP  I
     ...PUMP  2
     ..PRIMARY CYCLONE
       SECONDARY CYCLONES
                                                                                                                                 FOAM COLLECTION
                                                                                                                                 TROUGH
 PCV.., ..PRESSURE CONTROL VALVE
 LLC.... LIQUID LEVEL CONTROLLER
                                                                                                                                 DISTRIBUTION
                                                                                                                                 HEADER
                                                                                                                                 BOTTOM DRAIN
                                                                                                                                 FOR SETTLED
                                                                                                                                 SOLIDS
 FRESH WATFR SUPPLY
                                                                                                                                                AIR
                                                                                                                                              COMPRESSOR
   TO MAIN IN|.ET
   JUNCTION BOX
                                                                                                                                  LIQUID  COLLECTION
                                                                 DETAILED   DIAGRAM
                                                            DEMONSTRATION  PILOT PLANT
                                                                     (FIGURE  6a)
                                                                                                                                                         39

-------
         particles  might tend to overload the secondary




         cyclones  and clog the apex valves.




     2)   Experimental flexibility was needed so that various




         cyclone  combinations could be studied to obtain the




         maximum  removal of dense particles.






      The hydrocyclone overflow passed through the air dissolving




tank and on  to  a  pressure control device consisting of two, 2-




inch diaphragm  valves.  One valve was operated by a pneumatic




activator;  the  other valve was manually operated (Figure 7).




This dual operational capacity was included for testing purposes.




For flow rates  greater than 350 GPM, both control valves were




necessary to handle the flow.  Wastes entered the air flotation




tank through a  6-inch header with 2-inch nozzles evenly spaced




along it and passing through the end wall of the tank (Figure 8).




The air  flotation  tank was 20 feet wide and 15 feet long and was




divided  into two  cells, each 10 feet wide, for greater experimental




flexibility.  The  cell wall height, 29-1/4 inches, was dictated




by the size  and availability of the chain sprockets used for




the foam scraper  mechanism.  The flotation chamber of each cell




was 10 feet  wide  by 12 feet long; the remaining  3 feet of




length was used as  a foam trough and liquid effluent collector.






      Solid  and liquid effluent wastes from the air flotation




tank were piped into Tanks 2, 3, 4, and 5, for collection,




sampling and disposal.  Disposal was accomplished by remixing




and returning the wastes to the Fort Smith sewage distribution




box.
                              40

-------
THE PRESSURE CONTROL VALVES
          FIGURE 7
              41

-------
                                   TOP SCRAPER
 .£>

 N3
     SLUDGE
     DRAIN
 INFLUENT
FROM AIR
DISSOLVING
TANK  AND
PRESS.  CONTROL
VALVES
                      . - •    -        .
            '•'.•.'. BOTTGMSCRAPER •.>•.••.
CLEAN WATER
EFFLUENT
        DRAIN FOR
SETTLED SOLIDS
                                          FLOTATION  TANK
                                             FIGURE  8

-------
        SECTION VII






         SAMPLING






            AND






INITIAL PLANT MODIFICATIONS

-------
                     SAMPLING AND




              INITIAL PLANT MODIFICATIONS









     Following the commissioning of the pilot plant  and  the




initial start-up exercises, a program of sample-point  and




sampling-technique evaluation was initiated.  Figure 9 is




a schematic diagram of the sampling points  finally  selected




for the demonstration plant.  Note that sampling  points  are




located so that the efficiency of each major piece  of




equipment can be ascertained.  Most sampling points  were




controlled by a diaphragm valve.  In most cases composite  samples




were accumulated every 1/2 hour on a 4- or  8-hour schedule.




Grab samples were also used as the need arose.  Samples  were  placed




in gallon jugs and immediately iced to slow chemical and




biological action.






     Sampling difficulties with the liquid  effluent  or over-




flow from the cyclones made it impossible to conduct detailed




material balances for evaluation of performance.  In some  cases




it was suspected that the cyclones were breaking  up  part of  the




larger or more fragile solids.  Initially,  sampling  was  done




from 1/2 inch valves which drained from the center  of  the  pipe




installed immediately down-stream of the cyclone  overflows.




Because of the difficulty experienced in obtaining  duplicate




samples, it was theorized that the swirling motion  imparted




to the liquid as it passed through the cyclones was  carried




on by the liquid as it left the cyclone causing the  solid
                           43

-------
        FROM
        INLET JUNCTION
                BOX

    KEY

 P-l	PUMP*I
 P-2	PUMP*2
 C-l.	PRIMARY CYCLONE
 f* 9> 1
 ?.§ 	SECONDARY CYCLONES

 PCV	PRESSURE CONTROL VALVE

 M-2f"— MIXERS
 M-3)
 LLC	LIQUID LEVEL CONTROLLER
©.	SAMPLE POINT
                                                                                                                                           BOTTOM DRAIN
                                                                                                                                           FOR SETTLED
                                                                                                                                           SOLIDS
       FRESH WATER SUPPLY
        TO MAIN INLET
        JUNCTION
                                                                                                                                           LIQUID COLLECTION
                                                                            SAMPLE POINT DIAGRAM
                                                                       DEMONSTRATION PILOT  PLANT
                                                                               (  FIGURE  9 )

-------
particles to remain near the periphery  of  the  flow  rather




than being mixed thoroughly with  the  liquid  as  it passed




through the pipe.  Additionally,  some of  the duplication




difficulties were undoubtedly due  to  rapidly changing  waste




characteristics.







     Laboratory analysis of the samples were performed to




ascertain the following:




     1)  pH.




     2)  Turbidity.




     3)  Total suspended solids.




     4)  Volatile suspended solids.




     5)  Total solids .




     6)  Total volatile solids.




     7)  Total nitrogen.




     8)  Total phosphates.




     9)  Biochemical oxygen demand  (BOD).






     The laboratory analyses were  accomplished  using  the




methods outlined in "Standard Methods for  the  Examination  of




Water and Waste Water," 12th Edition, published jointly by




the American Public Health Association, the  American  Waterworks




Association, and The Water Pollution  Control Federation (32).




Laboratory quality control procedures suggested by  the Taft




Engineering Center, FWPCA, Cincinnati,  Ohio, were used.






     Two modifications added significantly to  the success  of




the demonstration.  These included  (1)  change  of the  point of
                           45

-------
influent selection from the Fort Smith sewage distribution




box to eliminate much of the industrial waste, and (2) the




addition of a baffle plate in the flotation cell to eliminate




large bubbles.






     The wastes arriving at the distribution box at Fort




Smith's sewage disposal plant consisted of a mixture of




industrial wastes and domestic sewage.  Laboratory analyses




showed wide variations in both pH and total suspended solids.




Some of these variations are illustrated in the appendix.  The




industries discharging waste into the sewage system at Fort




Smith include a fertilizer plant, packing houses, a slaughter-




house, a major appliance manufacturer, and several metal




plating and fabricating shops.  These industries cause Fort




Smith sewage to vary quite drastically from domestic sewage




in both physical and chemical makeup.  At times acid wastes




reduced the pH to a value of 3.2.  Heavy intermittent loads




of hair, blood ,and animal greases were also noted.






     Wastes from two Fort Smith collection systems, Mill




Creek and "P" Street, were mixed in the distribution box.




The Mill Creek sewage main carried primarily domestic wastes,




but the major appliance manufacturing plant and the slaughter-




house also discharged their wastes into the Mill Creek system.






     The "P" Street collection system contained a mixture  of




domestic wastes and heavy industrial wastes which was charac-




terized by a high percentage of nonvolatile suspended solids




and a widely varying pH.
                             46

-------
     Wastes flowed from the distribution box to the Fort Smith




clarifiers when gates "A" and "D" were opened and also flowed




to the demonstration plant when gates "B" and "C" were opened




(Figure 10).   To prevent the "P" Street wastes from entering




the demonstration plant the ends of two 4-inch pipes were




inserted deep into the Mill Creek inlet.  The other ends of




the pipes were passed through two flanged holes in a 12-inch^




wide steel plate installed beneath gate "B"  (Figure 11).




This plate raised gate "B" so its top edge was 12 inches




above the top of closed gate "A".  The mixture of Mill Creek




and "P" Street wastes overflowed gate "A" to the clarifiers




while the hydraulic head thus produced forced Mill Creek wastes




through the 4-inch pipes into the demonstration plant.  The




modification  was effective in eliminating "P" Street wastes




from the demonstration plant influent.






     The air  flotation cell as originally built permitted




large bubbles of air to rise through the liquid and disrupt




the mat of floating solids.  A baffle plate was installed above




the liquid inlet nozzles to trap and vent these bubbles  (Figure 12)




It should be  possible to accomplish the venting by inverting




the inlet header to the air flotation cell so that the waste




liquid exits  the inlet header from the bottom rather than the




top.  The large bubbles of air would then rise to the top of




the inlet header where they could be vented with a 1/2-inch




pipe.  Figure 13a shows the inlet header as built; Figure 13b




shows the recommended modification.
                             47

-------
    SLIDE GATES


      GATE 'D1
TO FT SMITH
CLARIFIERS
       GATE 'A'
                           OVERFLOW TO
                          ARKANSAS  RIVER
            /—GATE 'C'
                  TO DEMONSTRATION
                  PLANT
                                                    GATE  'B1
                   MILL CREEK
                      INLET
>" STREET
   INLET
                                 >LAr
            DISTRIBUTION BOX AT THE  FT SMITH V  STREET
                      POLLUTION CONTROL FACILITY
                                FIGURE 10
                                 48

-------
                            OVERFLOW TO
                          ARKANSAS  RIVER
      GATE 'D1
TO FT.  SMITH
CLARIFIERS
        GATE A'
                                                          GATES
                                                     GATE 'C1
                                             TO DEMONSTRATION
                                             PLANT
                                                    GATE 'B'
                                        STREET
                                        INLET
         MILL  CREEK
           INLET
                      PLAN

MODIFICATION  OF DISTRIBUTION  BOX  AT  FT SMITH

   "P" STREET  POLLUTION CONTROL   FACILITY
 WASTE TO
 FT. SMITH
 CLARIFIERS
                                                    LIQUID LEVEL
                                             WASTE TO
                                             DEMONSTRATION
                                             PLANT
                                                 \
                                                   STEEL PLATE
                      MILL     CAPPED      "P"
                  CREEK INLET         STREET INLET

                           SECTION A-A
                            FIGURE 11
                                49

-------
                                       AIR  DISCHARGE
INFLUENT
                                            TOP  SCRAPER
                             ;^,'.:':.'.'-ZlLIQUID LEVEL;
                             ^•^i^-:  :.'-•••••//.•;:.••.
                             '"'I'-"'.r^^^-BAFFLE PLATE
              BOTTOM
              DRAIN
                               FIGURE 12
                                  50

-------
   INFLUENT FROM AIR
   DISSOLVING TANK AND
   PRESS. CONTROL VALVES
VENT
/INFI
                (a)  INLET  HEADER AS  BUILT
INFLUENT FROM AIR
DISSOLVING TANK
AND PRESS. CONTROL
VALVES
            (b) SUGGESTED DESIGN FOR INLET  HEADER
                           FIGURE  13
                             51

-------
     During commissioning and start-up activities in the fall




of 1967 it was noted that rain beat some of the particles down




out of the floating mat; extremely high winds had a similar




effect.  To protect the foam, a Visqueen cover was installed




over the entire air flotation tank.  Location of a dissolved-




air flotation unit so as to take advantage of the protection




offered by already existing walls and cover should be considered.






     Photographs of the demonstration plant appear in Appendix




A.  Appendix B shows the Fort Smith drainage area, and Appendix




C is a resume of construction costs.
                           52

-------
     SECTION VIII






TESTING AND EVALUATION

-------
                   TESTING AND EVALUATION








     Two groups of tests were scheduled for completion at the




Fort Smith demonstration plant.  The first group, called the




basic data collection tests,  were selected to perfect operating




techniques and  parameters for the plant.  The tests included




operation of the plant with various air dissolving pressures,




determination of optimum air feed rates, and the determination




of optimum waste flow rates.   Various chemical flocculating




agents were tried in jar tests.   Results of the jar tests were




later used in determining the best chemicals for use in the




demonstration plant.  During the period of basic data collection,




sampling and laboratory analysis techniques were evaluated.




Retention time  studies using tracer dyes were also performed.






     Upon completion of the basic data collection tests the




second group of tests were scheduled.  The second group of




tests included:




     1)  Equipment testing.




     2)  Chemical testing.




     3)  Rain event testing.




Rain event testing had precedence over all other testing;




arrangements were made so that personnel were on call whenever




a storm event occurred, even if this event occurred after




normal working hours or during weekends.
                             53

-------
      Table 2 lists the  removal percentages  of  the various




waste components when different equipment  combinations were




used.  No chemical aids  to  flocculation were  used during this




series of tests.






      As indicated in Table  2, the  equipment  combinations in




this phase of operations were:  (1)  All the  separatory




equipment including screen,  four  cyclones, and  air flotation




tank; (2) The screen and air  flotation tank;  (3) The screen,




primary cyclone, and air flotation  tank;  (4)  The screen, three




secondary cyclones, and  air  flotation tank;  (5) The screen, two




secondary cyclones, and  air  flotation tank.   A  one-way analysis




of variance was performed on  the  results.  The  computations and




resulting analysis are shown  in Tables D-5, D-6, and D-7,




in Appendix, D, pages D-48  through  D-58.






      These analysis show that:






      1)  There is a statistically-significant  difference




          between the suspended solids removal  rates.   The




          best removal rates  were obtained when all the




          separatory equipment was  in use and when two




          secondary cyclones  and  the flotation  tank were in use.




      2)  Any differences between the rates of  BOD reduction are




          due to chance, and  changes in auxiliary separatory




          equipment do not significantly affect BOD reduction




          rates.

-------
                                        TABLE  2

                        PERCENT REMOVAL OF  SEWAGE  COMPONENTS WHEN

                       DIFFERENT EQUIPMENT  COMBINATIONS WERE USED

                                (NO CHEMICAL FLOCCULANTS)
Equipment Used
All Equipment
Screen &
Flotation Cell

Screen, Primary
Cyclone & Flo-
tation Cell

Screen, 3 Sec-
ondary Cyclones
& Flotation Cell

Screen, 2 Sec-
ondary & Flo-
tation Cell

Removal of
Suspended
Solids
X
62
49
49
53
65
95% C.I,
59 to 65
42 to 57
43 to 55
46 to 70
57 to 73
Reduction
of BOD
X~
26
27
35
36
41
95% C.I.
18 to 34
3 to 65
16 to 54
15 to 57
5 to 80
Removal of
Total Solids
X
17
27
16
23
23
95% C,I.
7 to 27
0 to 70
0 to 65
13 to 33
20 to 26
Removal of
Total
Phosphorous
X
J
:
\
I
.4
95% C.I.
t
8 tc
,
\
3 20
f
Removal of
Total Nitrogen
X
i
L
,
[
i
f
95% C.I.
i
3
,
i
to 6
r
X * Arithmetic Mean
95% C.I. « 95% Confidence Interval
                                           55

-------
     Because total nitrogen and total phosphorus content in




the waste treated at the demonstration pilot plant was primarily




due to dissolved solids, a cursory  examination of the data is




sufficient to indicate that there is no  significant difference




in the removal rates of these  components in the various




operational modes.  Further examination  shows that the total




nitrogen phosphate removal was  14 percent; Table 2 indicates




the 95 percent confidence intervals  for  the removal rates in




both cases.






     The results indicate that  the  dissolved air flotation




system is capable of removing  up  to  65 percent of suspended




solids after the influent waste has  been screened to remove gross




solids.






     The BOD reduction varies  from  26 to 41 percent with a




mean of 33 percent.  This compares  favorably with the removal




by conventional primary treatment plants.  The BOD and total




solids removal rates can be attributed to the removal of




suspended solids in the influent  waste.






     A chemical testing program was  accomplished.  Letters




of inquiry sent to various chemical  companies brought offers




of technical assistance in the  initial testing of the chemical




additives.  Jar tests were used to  reduce the wide field of




possibilities, and the most promising chemicals were tried in




conjunction with each other in  attempts  to achieve even better




results.   Results of the jar , tests  were  applied to full scale




demonstration plant operation.
                            56

-------
     The chemical companies volunteering to participate in the




program included:






     1)  Calgon Corporation.




     2)  Dow Chemical Company.




     3)  Drew Chemical Corporation.




     4)  Pennsalt Chemicals Corporation.




     5)  Tretolite Division of Petrolite Corporation.






     Letters of inquiry to several other manufactures of waste




water chemical additives brought no response.






     In almost all cases, the chemical additives were used as




"polishing agents" to improve the performance of the alum or




lime used as the primary or main flocculant.  The data obtained




are by no means exhaustive.  In some cases not enough chemical




additive was available for extensive testing.  In other cases




equipment problems, corrosion, and plugging prevented attempts




to inject the chemicals into the waste stream.






     Chemical feed rates were usually determined by  first




adjusting the alum feed rate to give the least turbid effluent,




then adding increments of polishing agent  chemicals  to further




decrease turbidity.  Effects of feed rate  changes were apparent




in the effluent waste stream within  10  minutes of the change.




Because of the extremely variable  strength and pH of the  influent




waste, it was impossible to maintain optimum  chemical  feed




rates for longer than  1/2  hour.    Operating procedure  was
                              57

-------
to determine optimum feed rates at  the start of a test run




and continue the test without changes in  this feed rate.






     Some polishing agents exhibited a synergistic effect




in combination with alum so  that  the alum feed rate could be




reduced. Ferric chloride is  an example.






     Data obtained for ferric chloride and a combination of




ferric chloride, alum,  and Tretolite FR-50 (a polyelectrolyte)




are the result of a rather limited  testing program.  The




extremely corrosive ferric chloride made  extensive testing




impossible.  Ferric chloride was  fed to the system by




siphoning it from plastic-lined drums into Tank 1.  When tests




using lime were performed, lime was also  introduced into the




waste stream by siphoning into Tank 1.  Tests using alum and




the polyelectrolytes indicated that the best point of injection




was after the air dissolving tank.  This  may well have been




the case with ferric chloride and lime also, and better results




might have been obtained if  they  had been injected after the




air dissolving tank.






     T^ble 3 lists the results obtained when various chemical




flocculation aids were used  during  periods of no rain.  In




all cases all the separatory equipment was in use except as




noted.






     Chemical feed rates varied,  as previously noted, but




ranged as follows:
                              58

-------
                                                TABLE 3

                             PERCENT REMOVAL OF THE VARIOUS  COMPONENTS  WHEN

                             DIFFERENT CHEMICAL TREATMENTS WERE  USED.   ALL

                             MECHANICAL SEPARATORY EQUIPMENT  WAS  ON  STREAM.
Chemicals Used
No Chemicals
Alum Only
Alum + Tretolite
FR-50
Alum + Dow
SA118.1A
Removal of
Suspended Solids
X
62
64
69
93
95% C.I.
59 to 65
22 to 100
59 to 80
88 to 98
Reduction of
BOD
X
26
47
53
63
95% C.I.
18 to 34
22 to 71
39 to 66
45 to 81
Removal
Total Solids
X
17
19
34
31
95% C.I.
7 to 27
9 to 30
16 to 59
16 to 46
Removal of
Total Phosphorous
X
29
53
43
34
95% C.I.
0 to 100
29 to 77
27 to 59
12 to 56
Removal
Total Nitrogen
x"
13
5
5
7
95% C.I.
10 to 16
2 to 8
2 to 8
0 to 10
           "There is insufficient data for full statistical analysis  of  the  following  results:
FeCl3 Only
FeCl3 + Alum +
Tretolite FR-50
Alum + Tretolite
FR-50 (Screen, 3
Secondary Cy-
clones & Flota-
tion Tank)
90

95

89



84 to 96

89 to 100

70 to 100



42

86

68



8 to 76

53 to 100

25 to 100



19

58

60



0 to 65

15 to 95

15 to 100



73

80





30 to 100

35 to 100





6

27





0 to 50

0 to 45





X = Arithmetic Mean
95% C.I. = 95% Confidence Interval
                                                   59

-------
     1)  Alum - 15 mg/1 to 175 mg/1.




     2)  Tretolite FR-50 - 1 mg/1 to 30 mg/1.




     3)  Dow SA1188.1A - 1 mg/1 to 10 mg/1.




     4)  Ferric Chloride - 10 mg/1 to 60 mg/1.






     Computations and the resulting analyses are shown in




Appendix D, pages D-70 through D-88 and in Tables D-8, D-9 ,



D-10, D-ll.






     The analyses show that:






     1)  Of the chemicals tried, alum plus Dow SA1188.1A




         provides the most effective treatment for suspended




         solids removal.






     2)  There is no apparent statistical difference between




         the BOD reduction rates, the total solids removal




         rates, the total phosphorus  and the total nitrogen




         removal rates for the chemical treatments listed in




         Table 3.
                             60

-------
     The demonstration plant was operated during every rain




event with total precipitation of 0.1 inch or more.  Results




of these operations are shown in Table 4.  Chemical feed rates




were varied to yield the least turbid effluent and then left




at that rate for the remainder of the storm event or sample




period.  Typical feed rates were:   (1) alum - 5 mg/1 to 175




mg/1; (2) Tretolite FR-50 - 1 mg/1  to 30 mg/1.






     Note that Table 4 shows that treatment with alum resulted




in poorer removal rates than no treatment at all.  However,




there were so few rain events that  the computed means have a




wide confidence interval (essentially, there can be only a




very low confidence in the answer).  The statistical analyses




found in Appendix D, Tables D-l, D-2, D-3 , and D-4, pages D-21




through D-38 bear this out






     The analyses show that:




     1)  Suspended solids removal during storm events is not




         a function of the treatment or  chemicals used.




     2)  There was no significant difference in BOD reduction




         between treatments using no chemicals and treatments




         using alum.  However, BOD  reduction during the




         operations using alum plus Tretolite FR-50 was




         significantly better than  the other two treatments.




     3)  Alum plus Tretolite FR-50  was significantly better




         in reducing total solids than was treatment with




         alum or without chemicals.
                           61

-------
                                              TABLE 4




                   PERCENT REMOVALS OF THE VARIOUS COMPONENTS DURING RAIN EVENTS.




                         ALL MECHANICAL SEPARATORY EQUIPMENT WAS ON STREAM.
Modes of Operation
No Chemicals
Alum Only
Alum + Tretolite
FR-50
Removal of
Suspended
Solids
X
69
56
84
95% C.I.
40 to 98
34 to 78
82 to 86
Reduction
of
BOD
X
40
35
73
95% C.I.
8 to 76
9 to 61
67 to 79
Removal of
Total
Solids
JC
24
36
52
95% C.I.
11 to 57
23 to 48
43 to 60
Removal of
Total
Phosphorous
X
48
30
74
95% C.I.
6 to 80
2 to 72
56 to 92
Removal of
Total
Nitrogen
X
4

6
95% C.I.
0 to 50
	
0 to 45
X  =  Arithmetic Mean




95% C.I.  =  95% Confidence Interval
                                                 62

-------
     4)  Removal rates of  total phosphorus  were  unaffected  by




         chemical treatment  or lack  of  chemical  treatment.




     5)  There was insufficient data concerning  total  nitrogen




         removals to make  any analysis.






     A resume of reductions  in suspended  solids,  BOD,




and total solids appears in  Table  5.






     Table 6 lists some of the various  components of Fort




Smith sewage during both dry weather and  rain  events and




compares them to the content of a  typical medium  strength




sewage (33, 34) .






     During dry  weather the  total  solids  content  of  Fort




Smith sewage is  about 25 percent less than  typical waste,




however, the organic content of each waste  is  nearly the  same.




Fort Smith's dry weather sewage contains  a  greater percentage




of suspended solids, but again the percentages of volatile




content are much the same.






     The high phosphate content of dry  weather sewage  may be




due to the discharge of waste from a fertilizer  plant  into




the Mill Creek force main.  A satisfactory  explanation for  the




low total nitrogen content could not  be found.






     During rain events both total solids and  suspended solids




content increased.   In many other  cities  solids  concentration




decreases during  rain events.  The organic  fraction  decreased




for both total and suspended solids.  Dilution of phosphate




content was also  observed.
                            63

-------
                             TABLE 5

            PERCENT REMOVAL OF SEVERAL COMPONENTS WHEN
            DIFFERENT EQUIPMENT COMBINATIONS WERE USED

                          (No Chemicals)
Equipment Used
Screen i Flotation
Cell
Screen, Primary
Cyclone & Flo-
tation Cell
Screen, 3 Secon-
dary Cyclones &
Flotation Cell
Screen, 2 Secon-
dary Cyclones &
Flotation Cell
Removal Total
Suspended Solids
X
49
49
53
65
95% C.I.
42 to 57
43 to 55
46 to 70
57 to 80
Reduction
BOD
ic
27
35
36
41
95% C.I.
3 to 65
16 to 54
15 to 57
5 to 80
Removal
Total Solids
X
27
16
23
23
95% C.I.
0 to 70
0 to 65
13 to 33
20 to 26
               PERCENT REMOVAL OF SEVERAL COMPONENTS
           WHEN DIFFERENT CHEMICAL TREATMENTS WERE USED.
        ALL MECHANICAL SEPARATORY EQUIPMENT WAS ON STREAM.


Chemical Used
No Chemicals
Alum Only
Alum + Tretolite
FR-50
Alum + Dow
SA1188.1A
Removal Total
Suspended Solids
X
62
64

69

93
95% C.I.
59 to 65
22 to 100

59 to 80

88 to 98
Reduction
BOD
x"
26
47

53

63
95% C.I.
18 to 34
22 to 71

39 to 66

45 to 81
Removal
Total Solids
X
17
19

34

31
95% C.I.
7 to 27
9 to 30

16 to 51

16 to 46
There is insufficient data for full statistical analysis of the
                            following:
Fed, Only
FeCl, + Alum +
Tretolite FR-50
*Alura + Tretolite
FR-50
90
95
89
84 to 96
89 to 100
70 to 100
42
86
68
8 to 76
53 to 100
25 to 100
19
58
60
0 to 65
15 to 95
15 to 100
   Primary Cyclone not used in this instance.
       PERCENT REMOVAL OF SEVERAL COMPONENTS
                DURING RAIN EVENTS.

ALL MECHANICAL SEPARATORY EQUIPMENT WAS ON STREAM.
Modes of Operation
No Chemicals
Alum Only
Alun + Tretolite
FR-50
Removal Total
Suspended Solids
X
69
56
84
95% C.I.
40 to 98
34 to 78
82 to 86
Reduction
BOD
X
40
35
73
95% C.I.
8 to 76
9 to 61
67 to 79
Removal
Total Solids
3c
24
36
52
95% C.I.
11 to 57
23 to 48
43 to 60
Tables 2, 3,  4, and 5 contain abbreviations for

several statistical terms.  They are(

             X-Ex£
                TT~

      Where X - sample arithmetic mean,

           x. - experimental values, and

            N « number of values.
     95% C.I. - The 95% Confidence Interval.  The data

                indicates there is a 95% probability

                (chance) that the true or population

                arithmetic mean lies between these two

                values inclusive.  Alternatively, there

                is a 5% probability that the true mean

                lies outside the given set of values.
                                                                                                                     64

-------
                        TABLE 6
            COMPARISON OF SEWAGE STRENGTHS *
Component
Total Solids
Total Volatile Solids
Total Volatile Solids x 100
Total solids
Suspended Solids
Volatile Suspended Solids
Suspended Solids v inn
Total Solids
Volatile Suspended Solids Y -\ nn
Suspended Solids
BOD
Total Nitrogen
Total Phosphate
pH
Turbidity

Fort Smith Sewage
Dry
Weather
mg/1
621
349
56%
272
195
44%
72%
174
18
40
7.0
180.0
J.U.
Rain
Events
mg/1
880
396
45%
534
273
61%
51%
212
16
28
7.0
231.0
J.U.
Typical Medium
Strength Sewage
(33, 34)
mg/1
880
420
52%
200
135
25%
68%
210
40
10



     *From the above table, it can be  seen  that  wet  weather
solids content is higher than the dry  weather  content.   This
fact does not support opinions that  bypassing  during rain  events
constitutes but a minor pollution problem because  wastes are
weak and diluted.  If the above data is  typical  of storm weather
flows from many municipalities, the  importance of  controlling
excess flows, rather than bypassing, becomes more  apparent.
                           65

-------
     Because the demonstration plant was contracted to test




the feasibility of operation during storm events, several tests




were made to determine the time necessary for start-up.  These




tests were performed during storm events as well as during dry




weather operation.






     Starting activities included:






     1)  Starting the air compressor to build up enough




         pressure to close the dump valves on the cyclones.




     2)  Closing the drain valves at the bottom of the air




         dissolving tank.




     3)  Closing Gate "A" and opening Gate "C" in the Fort Smith




         sewage disposal plant distribution box.




     4)  Starting Pump P-l.






     Average time between arrival of operating personnel at




the plant site and start-up was 2 minutes.  In all tests,




Tank 1 was partially filled.  If Tank 1 were empty at the




start of the tests, one minute additional time would be




necessary.
                           66

-------
         SECTION IX






ADDITIONAL TESTING OF CHEMICAL




    AIDS TO FLOCCULATION

-------
            ADDITIONAL  TESTING  OF  CHEMICAL




                AIDS TO  FLOCCULATION









     Tables 7, 8, and 9  show  the results  of  testing  of




additional chemical aids  to flocculation.   The  data  collected




for inclusion in these  tables are  insufficient  for  inclusion




in Table 5.  However, the data  are  indicative of  the ability




of these various chemicals to aid  the  removal of  suspended




solids and to reduce BOD.  In many  of  the  tests included  in




the following tables, grab samples  were used as opposed  to




the composite samples which were used  to  compile  the data




for Table 3.   Some rain  events  occurred during  the  tests.  The




data which include percent reduction in BOD  are the  result  of




composite sampling.






     Chemical feed rates varied widely and  are  a  function of




influent waste strength  and pH.  Reduction  of turbidity  was




initially used as the basis for chemical  feed rate  adjustment.




However, little correlation could  be found  between  turbidity




and suspended solids due  to the widely varying  influent  waste




characteristics.






     Justification for  chemical treatment  depends largely upon




effluent water quality  specifications.  Data obtained during




the demonstration of the  dissolved-air flotation  unit indicate
                           67

-------
        TABLE  7




ADDITIONAL CHEMICAL  TESTS
Chemical Aids
75 mg/1 Alum + 25 mg/1 Dow SA1188.1A
75 mg/1 Alum + 50 mg/1 Dow SA1188.1A
75 mg/1 Alum + 50 mg/1 Dow SA1188.1A
75 mg/1 Alum + 1/4 mg/1 Dow A23
75 mg/1 Alum + 1/2 mg/1 Dow A23
75 mg/1 Alum = 1 mg/1 Dow A23
75 mg/1 Alum + 2 mg/1 Dow A23
75 mg/1 Alum + 2 1/2 mg/1 Dow A23
75 mg/1 Alum + 8 mg/1 Drew Floe 400
60 mg/1 Alum + 4 mg/1 Drew Floe 410
Suspended
Solids
% Removal
97
96
86
73
56
62
88
90
78
91
BOD
% Reduction
--
—
76
—

--
—
--
57
68
            68

-------
                          TABLE 8

                   ADDITIONAL CHEMICAL TESTS
Treatment
Lime (mg/1)
150
150
150
150
150
150
0
75
100
50
100
100
100
100
???
???
Drew Floe
Number

400
400
400
400
410
410
410
410
410
410
410
410**
410**
410
410
mg/1
0
2.5
1
5
2
5
5
5
5
5
1
2
2
10
2
1
Suspended Solids
Plant
Influent
mg/1
260
226
206
268*
242*
205*
32
116
80
56
66
98
200
274
322
264
Plant
Effluent
mg/1
100
58
54
126
126
94
26
54
66
54
64
60
90
88
78
70
Removal , %
62
74
74
53
48
54
19
53
18
4
3
39
55
68
76
74
*    Blood present in the influent stream.
**   Drew Floe injected before air dissolving tank.
???  Measuring equipment inoperative, feed rate unknown, data
     is included to indicate the potential of the polishing
     chemical.
Lime was injected immediately before the hydrocyclones except
     for the two cases marked  ??? .
Drew Floe was injected immediately after the air dissolving
     tank, except as noted.
                             69

-------
                         TABLE  9




                 ADDITIONAL  CHEMICAL  TESTS
Alum
mg/1
0
0
0
75
50
75
100
100
125
125

Calgon
ST 25*
mg/1
40
50
50
0
0
0
0
0
0

30
Calgon
St 266*
mg/1
25
25
30
0
10
10
15
20
20
25
20
Turbidity
Removal ,%
52
44
50
17
7
-
41
45
72
64
-
Suspended
Solids
Removal , %
61
58
73
48
42
21
42
45
56
65
83
*  ST 266  is  an  anionic  polyelectrolyte;  ST 25 is a clay.
                             70

-------
that its effluent waters were often of secondary treatment




plant quality when chemical aids were used.  The possible




savings in equipment and construction costs made possible by a




dissolved-air flotation system and chemical aids suggest their




consideration as alternatives to secondary treatment.






     Costs for various chemical treatments are listed in Table




10.  The chemicals are listed alphabetically, and the suggested




feed rates are those which gave best removal rates under the




influent waste conditions existing during the test.  No




conclusions have been made.  Freight expenses have not been




included.   Unit costs vary with quantity ordered; the minimum




order varies from single 55 gallon drums to 5,000 pound lots.






     An average specific gravity of 1.01 for waste water was




used in calculating the costs in Table 10.  Rates are given in




terms of cost per million gallons of waste rather than in




cost per pound of dry solids.






     Interviews with several filling station operators in the




Fort Smith area led to the conclusion that used crankcase oil




is often disposed of (illegally) by pouring it into  the floor




drains  in  the service station or into nearby storm water catch




basins.   Several chance observations bore out this fact.  In




order to determine the effectiveness of the dissolved-air




flotation  system in removing the oil washed through  the combined




sewers  during the first surge of a rain event, it was necessary




to inject  oil directly into the flow stream of the demonstration
                             71

-------
        TABLE  10




CHEMICAL TREATMENT  COSTS
Chemical Used
And Feed Rate,
mg/1
Dry Alum — 75
Liquid Alum - 75
Calgon ST266-20
+ Calgon ST25 - 30
Dry Alum - 75
+ Dow SA1188.1A - 25
Dry Alum - 75
Dow A23 - 2-1/2
l
Dry Alum - 60
Drewfloc 410 - 4
Dry Alum - 75
Drewfloc 400 - 8
Dry Alum - 30
Anhydrous Ferric
Chloride - 30
Tretolite FR-50 - 4
Anhydrous Ferric
Chloride - 56
Alum - 75
Tretolite Fr-50 -
15
Unit Cost

-------
plant.  This was done by using both chemical feed pumps and

by pouring oil into the suction stream of pump P-l.


     Several tests were performed in which oil was injected

into the waste stream or dumped into Tank 1.  Little or no

oil was visible in the effluent from the air flotation tank,

Tests in which analyses were performed confirmed the visual

observations.  Results are shown in Table IT.


                          TABLE 11

                      OIL REMOVAL TEST
     mg/1 Oil Injected                      mg/1 Oil in the
      into the System                       Plant Effluent
          Blank                                  0.6

           100                                   0.6

           200                                   0.6

           300                                   0.6



     The oil used for this test was SAE 30 motor oil which

had previously been used as a break-in oil for motor vehicles,

The oil was injected into an influent waste stream containing

slaughterhouse wastes as indicated by the presence of paunch

wastes and blood.  Table 11 indicates that all the injected

oil was removed from the system.  It is probable that the oil

which was not removed was emulsified or dissolved oil and

grease from the slaughterhouse operation.  The analytical
                             73

-------
procedures used for the determination of oil involved use of




toluene as an extractant.  Colorimetric methods were used to




analyze the toluene bearing the extracted oil.
                              74

-------
        SECTION X
COMPONENT PARTS PERFORMANCE

-------
              COMPONENT PARTS PERFORMANCE









                        S creen









     The initial design of  the pilot  demonstration  plant  called




for the evaluation of a 3-mesh (1/4 inch)  and  a  6-mesh  (1/8  inch)




screen.  Removal rates of suspended solids  by  these screens




varied from 6 percent to 49 percent.   Removal  rates were




dependent more upon time elapsed  since  cleaning  of  the  screen




than upon screen size.  Solids removal  was  also  a  function  of




the time of the day and waste characteristics.   Almost  no




screenings were collected in the  early  morning hours.   The




solids discharge volume increased  during  the  day,  reaching  a




peak in the late afternoon.  Frequent  manual  cleaning,  often




after 12 to 16 hours of operation, was  necessary to prevent




total clogging.  Clogging was caused  by the stapling of fibers




and hair over the wires of  the screen.






     The hair and fiber load was  so heavy  that addition of




plastic cleaning rings recommended by  the  screen manufacturer




proved ineffective.  The rate of  stapling  was  so rapid  that




the cleaning rings became entangled and immovable  soon  after




the cleaned screen was placed in  operation.






     The manufacturer supplied a  32-mesh  screen  at  his  own




expense for evaluation to replace  the  3-  and  6-mesh screens.




The 32-mesh screen provided markedly  improved  solids removal




and was in use for one month during which  time it  was  never
                           75

-------
cleaned.  When the screen was removed for return to the




manufacturer, it was still clean with no evidence of




stapled hair or fibers.






     The 32-mesh screen  removed between 13 percent and




61 percent of the suspended solids.  There are insufficient




data to state a statistically significant difference between




these removal rates and  those for the 3- and 6-mesh screens.




However, visual observations indicated that the 32-mesh




screen was far superior  to the 3- and 6-mesh screens.  Also,




the 32-mesh screen removed a volume of the solids so great




that screenings had to be continuously shoveled from the solids




collection box and wheelbarrowed to Fort Smith's grit disposal




system.






     The removal of this tremendous quantity of solids




improved the capacity of Pump P-l to the point where it was




necessary to bypass part of the flow to maintain a flow rate




of 350 GPM.






     The screen is essential for the treatment of combined




sewage; proper mesh size is important.  For other applications,




the screen may eliminate need for the cyclones.
                           76

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                        Cyclones









     The demonstration pilot plant was designed with one




primary cyclone and three secondary cyclones. Results  as




indicated in Table 12 show that a flow of  350 gallons  per




minute, two 10-inch cyclones are sufficient.  Cyclones provide




maximum efficiency in removing total suspended solids  when




liquid flow is near capacity.  Provision should be made in




the design of future systems so that additional cyclones can




be readily added if the through-put of the  system is increased.






     Table 12 lists the pressure differentials across  the




cyclones for varying flow rates and for several combinations




of flow paths through the cyclones.






     Cyclone efficiency is a function of pressure differential




across the cyclones and optimum pressure differentials indicated




by Tables 2 and 12 appear to be in the neighborhood of 20 psi.






     All four cyclones were equipped with  air-operated dump




valves signalled by an electrical impulse  coming  from  a timer.




During several storm events, fine clay silt  accumulated at




such a high rate that solids collection pots on all three




secondary cyclones filled and became plugged.  The plant had




to be shut down and the cyclones dismantled  and cleaned.  If




cyclones are retained they should be designed to  permit




continuous solids discharge.
                             77

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           TABLE 12






SUPPLEMENTARY DATA ON PRESSURE




     DROP ACROSS CYCLONES
Flow Thru
Plant,
GPM
350
350
350
350
350
350
350
385
300
250
200
200
200
Back
Pressure,
psi
50
40
30
20
50
50
50
50
50
50
50
50
50
Pressure Differential
Across Cyclones,
psi
Primary
Cyclone
22
20
20
21
20
not in use
not in use
24
14
9
3
5
not in use
Secondary Cyclones
1
10
10
11
10
not in use
20
10
12
6
4
3
15
15
2
10
10
9
7
not in use
20
10
9
6
2
0
not in use
not in use
3
10
10
10
12
not in use
not in use
7
11
8
5
3
not in use
not in use
              78

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                     AIR DISSOLVING TANK









     The  literature indicates that a liquid retention time of




one to three minutes is desirable for dissolving tanks.  The




air dissolving tank dissolved air by three separate mechanisms:






     1)   As  the air bubbles through the liquid in the inner




         stand pipe.




     2)   As  the liquid falls through the air cap in the outer




         stand pipe.




     3)   In  the turbulence produced as the falling liquid




         strikes the liquid surface at the bottom of the air




         dissolving tank.






     The  efficiency of the air dissolving tank was tested by




comparing suspended solids removal rates with changes  in air




pressure  in  the tank and with changes in air feed rate.  A




scattergram   of the results is shown in Table 13.  Values in




the body  of  the table are percent removal rates of suspended




solids .






     Additional equipment testing was scheduled to determine




the proper liquid level in the air dissolving tank.  Reference




to Figure 5  shows the liquid level controller was located in




such a way that liquid level control in the upper half  of the




sight glass  was not possible.  The results of the tests were




inconclusive; very little difference in the suspended  solids




removal rate was noticed  for all  controllable levels of liquid




in the air dissolving  tank.
                              79

-------
                TABLE 13
THE EFFECT OF AIR FEED RATE AND PRESSURE




  DIFFERENTIAL ON TSS REMOVAL, PERCENT






           Pressure psi

Air Feed Rate,
cf m
20
25
30
40
Mean Values of
Suspended
Solids Removed
60

73
58

65
50
64, 43

62
69
54
40

58
67, 51,
50, 28

51
30

53, 34


43
20


43

43
Mean Values of
Suspended
Solids Removed
54
54
51
69

                   fin

-------
      The Relationship Between Suspended  Solids Removal
            Efficiency and Pressure Differential
   Suspended
    Solids
   Removal,
    Percent
             70
             60
             40
             3O
                   10   2O   30   40   50   60  70
                             AP
                           psi

                          FIGURE 14

    Figure 14 illustrates that  suspended  solids removal

efficiency approaches a maximum in  the  neighborhood of 50
to 60 psig.  Table 13 shows  that there  is no  relationship

between air feed rates tested and  suspended solids removal
rate.  This is to be expected,  since  a  surplus air feed rate

was designed into the system.   Low  air  feed rates were not

tested.

    The chemical feed system was arranged so  that chemicals

could be injected into the waste stream before the cyclones,
immediately after the cyclones, or  immediately after the air

dissolving tank.  Various tests were  run to determine the
                            81

-------
optimum point of injecting chemicals.  In practically all cases




it was determined that best results were obtained when chemicals




were injected immediately after the air dissolving tank.




Little or no effect was noticed when chemicals were injected




before the cyclones.






     There were occasions when the feed lines to the chemical




feed pumps were clogged.  The addition of sight glasses or




rotameters in the chemical feed lines to show when chemicals




were being pumped might be helpful.  Feed pumps capable of




handling relatively thick slurries such as might be




encountered in the feeding of lime are also desirable.






     Two pressure control valves were included in the system




(see Figure 7).  One valve was automatically operated by a




liquid level controller; the other was regulated manually.  The




automatically operated valve worked very well.  It was also




relatively easy to maintain pressure in the air dissolving tank




using the manually operated pressure control valve.  Manually




operated valves should be adequate for most applications




except in remote or automatic operations.






                   Air Flotation Cell




     Two sets of scrapers were installed in the air flotation




cell.  The scrapers on the bottom of the cell were used to




scrape dense materials deposited on the bottom to a collection




channel.  The upper scrapers were used to remove the floating
                            82

-------
foam.  Both scrapers were driven by a 1/2 hp variable speed




motor which was included in the design to determine the optimum




rate of scraper travel.  The bottom scraper was activated by a




chain drive and fitted with an air-operated clutch and timer to




permit intermittent operation.  However, when the bottom




scraper was not kept in continuous operation, sediment deposited




on the bottom of the cell was picked up by turbulence and




carried over the exit weir with the effluent stream.






     Scraper travel of 6 to 8 feet per minute yielded a foam




that was sufficiently thin to flow readily in the foam collection




hopper.  If other means of removing the foam are used, such as




an endless belt or an auger, slower foam scraper speeds can be




used.






     The amount of water in the foam was dependent upon two




factors related to foam scraper speed:




     1)  The scraper blades extended below the  foam  into  the




         waste water in the flotation  tank.  As  the  blades




         moved up the foam collection  ramp, water was  pushed




         along.  At low scraper speeds  (4  ft/sec or  less),




         water was able to trickle past imperfections  in  the




         blades.



     2)  At low scraper speeds, the water  in the interstices




         between the foam particles had time to  drain  away;




         a dryer foam resulted.






     During most of the demonstration,  foam  consistency was




deliberately kept thin  to avoid having  to  wash  it  from  the  foam
                             83

-------
collection trough.   The mean total solids content of the foam




was 0.43 percent and varied from 0.08 percent  to 3.4 percent.



During experiments  to determine the maximum foam solids concen-




trations, scraper speeds of 2 to 3 feet per second were used




to yield foam consistencies of 5 percent to 7  percent.  All




foam samples were collected by sampling from Tank 4 with the




mixer in operation.






     Volatile foam  solids varied from 24.7 percent to 83.4



percent, with a mean of 70.3 percent volatility.  After standing




for several hours,  the foam broke and the dense material sank




to the bottom of the sample bottle.  The less  dense material




floated.  A layer of relatively clear water separated the two




fractions.  The high volatility of the foam suggests incineration,




after dewatering, as a possible method of sludge disposal.






     The air flotation cell was 29-1/4 inches  deep by 20 feet




wide by 15 feet long and was divided into two  cells, each 10




feet wide.  The exit weir was adjusted to a liquid depth of




19 inches.  The inlet nozzles entered the tank 5-3/4 inches



from the bottom so  the bubble rise was 13-1/4  inches.  The




effective flotation length of each cell was 12 feet.  The




remaining length was used for foam collection  and effluent




liquid collecting troughs (see Figure 8)-   The theoretical




hydraulic retention time of each air flotation cell was 8.2



minutes.  Assuming that the 5-3/4-inch layer of liquid below




the inlet nozzles is relatively quiescent, the theoretical




hydraulic retention time is 5.6 minutes.  This agrees closely
                             84

-------
with the value of 5 minutes indicated with tracer dye tests.




The bottom scraper moved counter to  the liquid flow and probably




set up a circular flow pattern with  the hydraulic effect of a




still layer.  The exit baffle was modified in an attempt to




increase the retention time.  Modification consisted of




moving the exit baffle nearer to the exit weir and extending




it to within 2 inches of the bottom  of the flotation tank.




Although the modification did not noticeably affect the




retention time, it did increase efficiency of suspended solids




removal approximately 5 percent, apparently by decreasing  some




hydraulic short-circuiting in the tank.






     Valves installed in the inlet leaders were  adjusted to




direct all flow through one cell in  an attempt to determine




the optimum flotation cell flow rate.  The pumping rates were




varied from 125 GPM to 380 GPM.  Design through-put per cell




was 175 GPM.  Pressure differential  and air feed rates were




held constant at 50 psig and 30 cfm, respectively; no chemicals




were used.  Results of this test shown in Table  14 lead to




the conclusion that the flotation tank had greater capacity




than the design value; there was little or no difference




between the rates of suspended solids removal for  the flow




rates used.
                             85

-------
                     TABLE 14

THE EFFECT OF FLOW RATE ON SUSPENDED SOLIDS REMOVAL
                                       Suspended Solids
                                            Removal
Pumping Rate         Effective Flotation
                    Tank Throughput Rate
    GPM                      GPM                    %

  350-380                  700-760                  60

  200-225                  400-450                  65

    175*                     350                    62

    150                      300                    61

    125                      250                    66


*  Design Flow Rate


     To determine the minimum depth of the flotation tank, a

series of holes were cut in the exit weir of one cell of the

flotation tank.  The location and size of the holes is

indicated in Figure 15.


0>


vj




t


36"





V|
L 	 : 	 1 — 1

36"





H
t

36"



Normal Liquid Lew

Vil ±

=«=
t
                     FIGURE 15
                        86

-------
     The lower holes were  covered  and sealed in order to test

the effect of lowering  the liquid  depth to 14-1/4 inches

(three-quarters of  the  designed  depth of 19 inches).  The lower

set of holes was used  to  test  the  efficiency of suspended solids

removal at one-half design depth.   The results shown in Table

15 show a sharp drop in efficiency for the shallower

cells and fix the minimum  depth  in the neighborhood of 19

inches.  A simultaneous test was performed using the unmodified

cell for comparison purposes.



                           TABLE  15
Liquid Depth, in.
                  EFFECTIVE  FLOTATION DEPTH
   Distance of
Bubble Rise, in
     19(unmodified cell)

     14.25

      9.5
Suspended
 Solids
Removal,%
13.25
8-. 5
3. 75
92.1
73.0
71.3
     To aid in suspended  solids  removal  in this test, 100 mg/1

alum and 20 mg/1 Tretolite  FR-50 were  used as flocculating

aids.  The tests were performed  during a period when there

was little variation in the  influent waste stream;  influent

pH was 7.1 and the influent  suspended  solids  content was

784 mg/1.
                             87

-------
         SECTION XI






BENEFIT-COST RELATIONSHIPS

-------
               BENEFIT-COST RELATIONSHIPS









     A hypothetical community was considered in order to




obtain an analysis and comparison of costs and benefit-cost




ratios.  75 rain events, averaging 4 hours each occur




annually in this community.  Run-off disposal is by means of




combined sewers which overflow directly into a nearby river.




The suspended solids content of the overflow averages 534 mg/1,




which was the average value at Fort Smith.






     It was assumed that the city needed to provide primary




treatment of the overflow to comply with effluent waste water




quality standards.  Conventional clarifiers and dissolved air




flotation were chosen for comparison.  The costs and benefits




of each method are presented in Table 16 for flow rates varying




from 1 MGD to 20 MGD.






     To aid in the analysis, it has been assumed that an




overflow outfall already exists above the high water line of




the river, so the cost of delivering the waste overflow to the




treatment plant need not be considered.  Land is available at




$100 per acre.  Twenty-year, 5.5 percent bonds will be used




for financing.  The expected life of both treatment plants is




50 years.






     Evans, et al., (35) in their study of the treatment of




urban storm water run-off suggest that during storm events,



conventional clarifiers with four hours retention time can
                            88

-------
                                                           TABLE 16
                                  COSTS  AND BENEFITS,  AIR FLOTATION ANP CONVENTIONAL CLARIFIERS
Capacity

MGD Treatment
Air
1
Conv
Air
2
Conv
Air
4
Conv
Air
8
Conv
Air
16
Conv
Air
20
Conv
Flotation

. Clarifier
Flotation

. Clarifier
Flotation

. Clarifier
Flotation

. Clarifier
Flotation

. Clarifier
Flotation

. Clarifier
Total
Installed
Cost
Including
Land
$26,380

44,520
43,270

69,435
73,085

108,225
123,440

168,950
208,495

263,550
253,135

308,465
Total
Interest
(3 5.5%
20
$29

48
47

76
80

119
135

185
229

290
278

339
yrs .
,020

,960
,600

,380
,400

,160
,800

,900
,420

,020
,460

,320
Annual
Amortized
Cost
$2,

4,
4,

7,
7,

11,
12,

17,
21,

27,
26,

32,
770

675
545

290
675

370
960

745
895

680
580

390
Annual
Operating &
Maintenance
Costs
$2,

1,
3,

1,
5,

2,
8,

2,
14,

4,
17,

5,
990

500
970

770
720

140
750

750
890

600
600

050
Lb
Suspended
Total Solids
Annual Removed
Benefit
Cost
Ratios
Cost Annually *
$5

6
8

9
13

13
21

20
36

32
44

37
,760 38,920

,175
,515 77,840

,060
,395 155,690

,510
,710 311,380

,495
,785 622,750

,280
,180 778,440

,440
6.8

6.3
9.1

8.6
11.6

11-. 5
14.3

15.2
16.9

19,3
17.6

20.8
* Lb   suspended solids removed/$.
                                                  89

-------
remove 70 percent of the suspended solids.  These values were

used as a basis for the design of the clarifiers, since the

removal rates approximate those attained during storm events

using dissolved-air flotation at Fort Smith.


     The bases for calculating operating and maintenance costs

are:


     1)  Electricity @ IC/hr/H.P.
                                      Horsepower
         Capacity           Flotation            Conventional
           MGD                Units               Clarifiers

            1                   50                    1
            2                   95                    1
            4                  180                    1
            8                  350                    2
           16                  680                    4
           20                  840                    4
     2)  Labor costs are the same for both air flotation units

         and conventional clarifiers of equal capacity at the

         rate of 4 hours per rain event for  the  1-,  2-,  4-,  and

         8-MGD plants and 8 hours per rain event  for  the larger

         plants.  Cleanup activities are responsible  for most

         of the labor charges.
                              90

-------
     3)   Maintenance

                     Air  Flotation         Conventional Clarifiers

         Labor       4  hours per week      1 hour per week
                     @  $3.00 per hour      @ $3.00 per hour

         Parts and    5% of  initial cost    1% of initial cost
         Supplies

     Cost analyses  are  provided for the installed clarifiers

and flotation units only  and do not include the costs of treat-

ing the  separated solids  and sludge or the effluent waste waters.

These cost factors  must be  included in any comprehensive cost

analysis (36).


     Table 17 shows that  only 0.1 as much land area is needed by

dissolved-air flotation units.   This could be important at

overflow points.


     The benefit-cost ratios in pounds of suspended solids

removed  per dollar  of annual cost, shown in Table 16, favor

dissolved-air flotation for capacities less than 8 MGD.

Figure 16 illustrates the data  of Table 16 in graphical form.


     If  dissolved-air flotation is used for treatment,

additional savings  are  realized because the floated foam has

a solids content  of 7 percent and a thickener will probably be

unnecessary.  Flotation cell underflow, containing solids which

sink to  the bottom, can be controlled to yield a low volume

sludge of 1 to 2  percent  consistency.  Mixing the solid screenings

with the underflow  will increase the solids content of the

foam-underflow mixture.  This sludge should be amenable to
                            91

-------
      24 -
•co-

•o
01
>
o
6
o>
•o
•o
01
tJ
c
 to
 3
 (A
      20
       16
       12
 (0

 O
 m
 o
                                    Dissolved-air flotation


                                    Conventional  Clarifiers
 
-------
                                       TABLE 17
PHYSICAL SIZES AND LAND AREAS
REQUIRED BY CONVENTIONAL CLARIFIERS
AND DISSOLVED AIR FLOTATION UNITS
Conventional Clarifiers Air Flotation
Tank Size
Capacity
MGD
1
2
4
8
16
20
Diameter
ft
50
70
100
140
200
150
Depth
ft
11
11
11
11
12
11
Number
Required
1
1
1
1
1
2
Area
Needed
sq ft
3600
6400
12100
22500
44100
50400
Cell
Length
12
12
12
12
12
12
Size
Width
10
10
10
40
40
40
Number
of Cells
2
4 *
8 *
4 *
8 *
10 *
Area
Required
sq ft
350
350
700
2000
4000
5000
* Cells can be stacked two high to conserve space.
                                         93

-------
direct vacuum filtration with an expected filter cake moisture




content of 70 percent (36).  Final disposition of the filter




cake is dependent upon local conditions.  Some typical options




include:




     1)  Incineration.




         a .   On site.




         b.   Trucking to off-site incinerator.




     2)  Burial.




     3)  Composting.






     Alternatives to dewatering the sludge on site include




digestion on site and pumping to an existing  treatment plant




for treatment.  On-site digestion appears to  present more




problems and is the less attractive.
                            94

-------
        SECTION XII






POSSIBILITIES FOR AUTOMATION




             AND




OTHER POTENTIAL APPLICATIONS

-------
                POSSIBILITIES FOR AUTOMATION




                             AND




                OTHER POTENTIAL APPLICATIONS









                  Automation Possibilities








     Results of the tests performed and observations obtained




at the plant site indicate that the operation might well be




automated.  In very few instances was  the operator necessary.




With the use of standard, easily available equipment, the




entire operation could be automated from start-up to shut., down.




An automated unit would also be adaptable for use at remote




locations.






     Detailed design of an automated unit is  somewhat dependent




upon conditions and location.  However, the basic premises




will remain fairly constant.  The modification  of the existing




Fort Smith plant will be used as an example in  the discussion




of the design of an automated dissolved-air flotation system.






     The design includes a method of disposing  of the foam




and the solid wastes from the screen,  the cyclones,  and  the




bottom of the flotation cell.  Some of the design modifications




recommended earlier in this  report have been  included in this




design.






     The following items are considered essential for the




modification.  Figure 17 is  a detailed diagram  of this  design.
                              95

-------
1)   Select start up mechanism.  The  criteria  is  the




    detection of increased flow to  the  Fort  Smith  municipal




    treating plant.




    a.   A liquid level sensor set at  a  predetermined




        level in the 12 ft concrete  "P" Street  interceptor




        will detect rising water and  will  signal the start




        of a sequential start-up, washing,  and  shut-down




        cycle .




    b.   Manual  start of the sequence.   (For  check  out of




        the unit.)




2)   Revise the  existing flow  rate measurement and  control




    sys tern.




    a.   A flow  controller signaled  by the  existing orifice-




        flow recorder system  will:




        1.  Actuate a pneumatic flow control valve (FCV-1)




            upstream of the air dissolving  tank.




        2.  Regulate air flow to the air dissolving  tank




            (T-7)  by means of a pressure control valve




            (PCV-3).




        3.  Open and close a  by pass valve  (BPV-1)




            controlling flow  to the primary  hydrocyclone (C-l)




    b.   Control of  the by pass valve (BPV-1)  may be




        provided through the  use of signals  from a liquid




        level controller (LLC-1) in the liquid  to  influent




        Tank 1.
                       96

-------
                                  SCREEN
       FROM MAJN
     DISTRIBUTION
         BOX

   J
-------
3)   Design a sequential turn-on, turn-off, clean-up, and




    shut-down cycle.




    a.  An electric signal will start the air compressor




        and energize all electrical control  circuits.




    b.  Air will open shut-down valve (SDV-1) and start




        the screen.




    c.  Air will close all dump valves.




    d.  A rising liquid level in Tank 1 will  close  a




        pump switch to :




        1.  Start Pump P-l.




        2.  Start the foam and bottom scrapers.




        3.  Start Chemical Feed Pump 1.




    e.  A high-low liquid level safety  shut-down will




        control SDV-1 and prevent  overflow of Tank  1.




    f.  The flow rate will be controlled  by  a signal  from




        a flow controller connected  to  the orifice  3  pen




        recorder system (FM-1), from liquid  level  controller




        (LLC-1), or from both.  The  signals  will:




        1.  Provide throttling  through  flow  control valve




            (FCV-1).




        2.  Control flow through  the primary cyclone  by




            opening by pass valve  (BPV-1) when  flow rates




            exceed  350 GPM.




        3.  Control flow to one flotation cell  by  opening




            by pass valve  (BPV-2)  when  flow  rates  exceed




            350 GPM.
                       98

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     4.  Regulate air flow to the air dissolving tank




         (T-7) by means of the pneumatically operated




         pressure control valve  (PCV-3).   Start Feed




         Pump-2 .




g.  An air operated valve signaled  by a  timer  on the




    chain drive turning the  bottom  scrapers will permit




    periodic dumping of the  bottom  sludge  in  the




    flotation cells.




h.  A liquid level controller  (LLC-2) will stop  the




    liquid effluent pump  (P-2)  in  the liquid  effluent




    Tank 2.




i.  Fort Smith Sewage Department personnel pump  the




    sludge hoppers to the existing  clarifiers  every




    2 hours.  Volumes of  sludge  and foam accumulated




    in 2 hours are not  expected  to  exceed  the  capacity




    of the storage facilities  (Tanks 3,  4  and 5).




    Mixers will be controlled  by liquid  level




    controllers.




j.  When the liquid level in the 12 ft  concrete  inter-




    ceptor falls  below  the  predetermined height  or at




    the discretion of  the Superintendent of the  Fort




    Smith Sewage  Disposal Facility, the  clean-up and




    shut-down sequence  will  begin.




k.  The shut-down valve (SDV-1)  will close.




1.  The pump  switch will  stop  Pump P-l  when the




    liquid level  falls  in the  liquid influent Tank 1.
                    99

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        An override switch will keep  the  screen  and




        scrapers in operation.




    m.   A signal will trigger an air  operated  valve,




        dumping fresh rinse water through  the  screen  into




        Tank 1.




    n.   Pump P-l will start, flushing  the  system with




        rinse water.




    o.   A timer will  close the fresh  water  valve and  stop




        the screen.  Pump P-l will stop at  the low  level




        signal.




    p.   The air compressor and scrapers will stop.




    q.   Dump valves will drain all lines  and the flotation




        cells to the  liquid effluent  Tank  1.   When  Tank




        2 is empty a  timer will turn  off  power to the




        electrical control circuits and reset  the air




        compressor switch to repeat the sequence on




        signal.




    r.   An electrical lockout will prevent  SDV-1 from




        opening when  the wash-out cycle is  in  operation.




4)   Replace the 3- and 6-mesh screens  with  screens  of




    32  mesh or smaller.  During these  tests, the 32-mesh




    screen exhibited  little or no tendency  to  blind




    because of stapling.




5)   Change the solids discharge system on  the  hydro-




    cyclones to continuous blowdown.   The  use  of smaller




    screens will permit the removal of the  automatic




    dump valves and the solids pots on the  hydrocyclones
                     100

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    and the installation of apex valves with small




    diameters.  This will permit continuous blowdown of




    solids with a bypass of approximately 3 percent




    of the liquid flow.




6)  Modify the hydrocyclone flow sequence.




    To accommodate a flow rate of 700 GPM, the primary




    cyclone (C-l) will be placed in parallel with the




    bank of secondary cyclones (C-2, C-3, C-4).   C-l will




    be cut out of the circuit at flow rates of 350 GPM




    or less.




7)  Select a discharge system for the flotation cell




    liquid effluents.




    The present demonstration plant remixes all the solid




    and liquid effluents.  Modification of the discharge




    system will permit the discharge of the separated




    solids and liquids.  The existing liquid effluent




    pump (P-2) will be moved to  the liquid effluent Tank 2.




    Liquid effluent from the flotation cells will be




    pumped to the exit cell of the Fort Smith distribution




    box, decreasing the hydraulic load in the Fort Smith




    sewage disposal plant and increasing  the efficiency




    of solids removal during storm events.




8)  Select a disposal system for the solids collected.




    a.  A gravity flow line will run from mixing Tank  3




        to an existing line upstream of the Fort Smith




        sludge pump.




    b.  A stop valve would prevent back flow.
                       101

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      c.  A pump (P-3) installed in mixing Tank 3 will pump




          the accumulated sludge and foam to the Fort Smith




          sludge thickeners.  The solids removed by the




          screens,  cyclones, and flotation cells would not




          pass through the Fort Smith clarifiers.  The




          automated unit thereby will decrease the solids




          load and  further increase the efficiency of the




          Fort Smith sewage disposal plant.




 9)  Redesign the sludge collection trough on the bottom




     of each flotation cell.




     The slotted pipe in the collection trough will be




     removed and replaced with an inclined plane to improve




     the bottom sludge collection efficiency, provide for




     a more positive hydraulic sweeping action, and minimize




     channeling.




10)  Design a spray jet system to wash the chains and




     sprockets during the clean-up cycle.






         Other Potential Applications









 Combined sewer and storm water overflows are not the




 only source of pollution in the nation's receiving




 waters.  The research project discussed in this report




 has suggested answers to industrial waste pollution




 problems as well.   Some of these are discussed below.
                      102

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One application  includes  use  by  the  meat  processing




industry.  Fort  Smith  sewage  contained  quantities  of




feathers, hair,  paunch wastes,  and blood.   These




materials were easily  removed by the plant.   Most  of




the blood was removed, and  a  very clear liquid effluent




was obtained.  However,  it  was  difficult  to  remove




all of the color.







Some present applications of  the dissoIved-air




flotation system were  discussed  in  Section IV.




Similar systems  have been used  in the petroleum




industry, and the  design  discussed  in this report




seems particularly  adaptable  to  oil  field applications.




Low retention time  plus  extreme  compactness  make




dissolved-air flotation  very  suitable for use on




offshore production platforms.







Dissolved-air flotation  systems  are  currently being




used by several  of  the food processing  industries.




Some canneries use  the air  flotation system to remove




suspended solids from  their process  wastes.   In most




cases, the air flotation  cells  being used are of  the




old design in which retention times  are approximately




one hour or  longer.  The  design  demonstrated at Fort




Smith is unique  in  that:




1)  Air is dissolved in  the entire  waste  flow, and




2)  The retention  time in the air flotation tank is




    extremely short.
                 103

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Future plants might well be designed around a basic




unit with dimensions the same as a single cell of the




air flotation tank located at Fort Smith; approximately




10 feet wide with an effective inner length of 12




feet.  An entire plant (0.5 MGD) could be contained




on a skid, trailer, or pad with dimensions of 10 feet




by 25 feet.  If additional hydraulic capacity is




necessary, tanks could be paralleled or  stacked one




above another.  The area of the pad not  occupied by




the air flotation tank would be used for the ancillary




equipment.






The same concept is sound for larger or  smaller




flotation cell dimensions and capacities.






Recommendations for future development of dissolved-




air flotation include:




1)  Further investigation using specific industrial




    wastes from the ferrous and nonferrous metal




    industries, packing houses, rendering plants and




    slaughterhouses, and the petrochemical and




    petroleum industries.




2)  Design and construction of a completely automatic,




    in-line plant to be used in one or more of the




    above applications.




3)  The construction and operation of a  pilot plant




    in which the specific goal would be  to test various
                 104

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    chemical aids to flocculation both singly and




    in combination, attempting to reduce suspended




    solids, BOD, total phosphates, and total nitrogen.




4)  Use of the dissolved-air flotation system as the




    primary treatment device in combination with




    various high rate secondary devices to produce




    a very high quality effluent waste water.  Suggested




    secondary devices include high rate trickling




    filters or a rapid sand filter (to remove the




    remaining suspended materials) followed by an




    activated carbon unit  (to remove  BOD and dissolved




    chemicals).  This step, in turn,  could be followed




    by chlorination or aeration or both.




5)  Use of the dissolved-air flotation unit with




    chemical aids as a replacement for both primary




    and secondary treatment plants.
                   105

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  SECTION XIII






ACKNOWLEDGEMENTS

-------
                      ACKNOWLEDGEMENTS


     The research team is most appreciative of  the aid and

assistance given them by a host of people and organizations.

The demonstration was carried to a successful completion by

their willing and unselfish support.
     Gene Andrews, Superintendent,
     Water Pollution Control Facilities  -  Springdale,  Arkansas

     Robert F. Andrews - Pennsalt  Chemical  Corporation

     Darrel L. Cornelius - Drew  Chemical  Company

     V.  Bruce Dorsett - Drew Chemical  Company

     Dr. Robert A. Gearheart, Professor  of  Sanitary  Engineering,
     University of Arkansas - Fayetteville,  Arkansas

     Everett H. Janssen - Calgon Corporation

     Dr. Edwin H. Klehr, Professor of  Water  and  Sanitary  Chemistry,
     Civil Engineering and Environmental Science,
     University of Oklahoma - Norman,  Oklahoma

     Webb Minor,  Superintendent,
     Water Pollution Control Facilities  - Russellville,  Arkansas

     Zack Mouradian - Southwestern Engineering Company

     Carl Reames, Superintendent,  and  his staff,
     npii street Sewage Pollution Control Facility  -
     Fort Smith,  Arkansas

     Professor George W. Reid,  Director
     Civil Engineering and Environmental Science
     University of Oklahoma - Norman,  Oklahoma

     Ray A.  Sierka, Graduate  Student
     Civil Engineering and Environmental Science
     University of Oklahoma - Norman,  Oklahoma

     G. Wade  Spencer  - Pennsalt Chemical Corporation
                               106

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           ACKNOWLEDGEMENTS - CONTINUED
Max I. Suchanek - Dow Chemical Company

Robert W. Taylor
Tretolite Division - Petrolite Corporation
                         107

-------
        SECTION  XIV







REFERENCES AND BIBLIOGRAPHY

-------
                         REFERENCES
(1)  USDI, FWPCA; "Problems of Combined Sewer Facilities and
     Overflows, 1967." Water Polution Control Research Series,
     WP-20-11, xii - xx, 2-5, 30-39, 74-86, 163-173.

(2)  Weiner, D. L., "Understanding  the World of  Sewage."  Can-
     Tex Industries, Mineral Wells,  Texas,  (1963),  3.

(3)  "Restoring the Quality of Our  Environment."  Report of
     the Environmental Pollution  Panel, President's  Science
     Advisory Committee,   1965, 158-167.

(4)  "Roundtable:  Wastes,  Separate and Combined  Sewers."
     Water and Waste Engineering, 5, 7, 26.  (1968).

(5)  Anon, "Salt Water in  the Sewers." American  City,  80, 12,
     112   (1965).

(6)  Peters, G. L. and Troemper,  A. P., "Reduction  of  Hydraulic
     sewer Loading by Downspout Removal."   Journal  Water
     Pollution Control Federation,  41, 1,  63-81  (1969).

(7)  Koelzer, Victor A., Bauer, William J.,  and  Dalton, Frank  E.;
     "The  Chicagoland Deep Tunnel Project  - A  Use of the  Under-
     ground  Storage Resource." Paper presented  at the  41st
     annual  meeting of the Water  Pollution Control  Federation,
     September 23, 1968, Chicago.

(8)  Overfield,  J. L. , Baxter, J. K. ,  Crawford,  H.  R., and
     Santry,  I.  W., "Increasing  Sewage  Flow Velocity by Using
     Chemical Additives."   Paper  presented at  WPCF Annual
     Meeting September 23, 1968,  Chicago.

(9)  Putnicki, G.  J.,  "FWPCA's Research  and Development Program."
     Water,  Southwest Water Works Journal, 50,  12,  25  (1969).

(10)  Hanson, C.  A. and Gotaas, H. D.,  "Sewage  Treatment by
     Flotation."  Sewage  Works  Journal,  15  2, 242-252 (1943).

(11)  Gaudin, A.  M.,  "Flotation."  1st edition,  McGraw Hill
     Book Co.,  Inc.,  New York,  N. Y.,  1932 .

(12)  Norris, U.  S.  Patent  #864,  856, September 3, 1907.

(13)  Elmore, F.  E.,  U.  S.  Patent #826,  411, May 11, 1907.

(14)  Suhman, Kirkpatrick-Picard,  and Ballot, U. S.  Patent #793,
     808.   July  4,  1906
                              108

-------
(15)   D'Arcy,  N.  A.,  Jr.,  "Dissolved  Air Flotation Separates
      Oil From Waste  Water."   Proceedings,  American Petroleum
      Institute,  31M,  3,  34-42 (1951).

(16)   Osterman, J.,  "Chrysler Plant Pretreats Oil Wastes by
      Flotation." Wastes  Engineering,  26,2, 69,  (1955).

(17)   Jacobsen, S.  E.  and  Meinhold, T.  F.,  "Removes Oil  by
      Dissolved-Air  Flotation."   Chemical Processing, 12-14,
      (February 1955).

(18)   Howe,  R.  H. L.,  "Mathematical Interpretation of Flotation
      for Solid-Liquid  Separation." in  "Biological Treatment
      of  Sewerage and  Industrial  Wastes." Reinhold Publishing
      Co.,  Inc.,  2nd  edition, New York, N.  Y., 1958, 241-250.

(19)   Vrablic,  R. R.,  "Fundamental Principles of Dissolved
      Air Flotation  of  Industrial Wastes."  Proceedings.	
      Industrial  Waste  Conference, Purdue University, (1959)
      743-779.

(20)   Eckenfelder, W.  W.,  Jr., Rooney,  T. F., Burger, T. B.,
      and Gruspier,  J.  T.,  "Dissolved Air Flotation of
      Biological  Sludges."  in "Biological Treatment of Sewerage
      and Industrial  Wastes,"Reinhold Publishing Co., Inc.,
      2nd edition, New  York,  N.  Y., 1958, 251-258.

(21)   Rohlich,  G. A.,  "Application of Air Flotation to
      Refinery Waste  Waters." Industrial and Engineering
      Chemistry,  46,  3,  304 (1954) .

(22)   Prather,  B. V.,  "Will Air  Flotation Remove the Chemical
      Oxygen Demand  of  Refinery  Waste Water?v Petroleum  Refinery,
      (May 1961), 177-180.

(23)   Hopper,  S.  H.,  and  McGowan, M.  C., "A Flotation Process
      for Water Purification." Journal  of the American Water-
      works  Association.  44,  8,  719-726  (1952).

(24)   Katz,  W.  J. and  Geinapolos, A., "Sludge Thickening by
      Dissolved Air  Flotation."  Paper presented  at Ohio  Water
      Pollution Control Conference, (June 16, 1967).

(25)   Masterson,  E.  M.  and  Pratt, J.  W. , "Applications of
      Pressure Flotation  Principles to  Process Equipment Design."in
      "Biological Treatment of Sewerage and Industrial Wastes,"
      Reinhold Publishing  Co., Inc.,  New York, N. Y., 2nd
      edition, 1958 ,  232-240.

(26)   Pryor, E. J.,  "Mineral  Processing." Elsevier Publishing
      Co., Amsterdam,  Holland 1965  222-232.
                              109

-------
(27)   Leniger,  H.  A.,  "General Remarks on Phase Separations
      and  Classification." in "Cyclones in Industry." Elsevier
      Publishing  Co.,  Amsterdam, Holland  1961  12-13.

(28)   Broer,  L. J.  F., "Flow Phenomena in Cyclones." in "Cyclones
      in  Industry." Elsevier Publishing Co., Amsterdam,
      Holland  1961,  33-45.

(29)   Van  Der Kolk, H.,  "Linking Cyclones in Series and Its
      Effect  on Total  Separation," in "Cyclones in Industry."
      Elsevier Publishing Co., Amsterdam, Holland, 1961,
      77-88.

(30)   Technical Bulletin no. 3301, "Krebs Cyclones" Krebs
      Engineers,  Palo  Alto,  California.

(31)   Perry,  J. H., "Chemical Engineers"Handbook." McGraw-
      Hill Book Co..  New York, N. Y., 4th edition 1963, 14-1 -
      14-69,  18-1 - 18-59.

(32)   American Public  Health Assn., Inc., "Standard Methods
      for  the Examination of Water and Wastewater." 12th edition,
      New  York, N.  Y.,  1965  .

(33)   Sawyer, C.  N.,  and McCarty, P. L., "Chemistry for
      Sanitary Engineers," McGraw-Hill Book Co., New York, N. Y.,
      2nd  edition,  1967, 466-472.

(34)   Steel,  E. W., "Water Supply and Sewerage," McGraw-Hill
      Book Co., New York, N. Y., 1960, 444-462.

(35)   Evans,  L.  S., Geldreich, R. S., Weibel,  S. R., and
      Robeck, G.  G.,  "Treatment of Urban Stormwater Runoff."
      Journal Water Pollution Control Federation, 40,  5,
      R162-R170 (1968).

(36)   Burd, R. S.,  "A Study of Sludge Handling and Disposal."
      USDI, FWPCA Publication WP-20-4, 130-159  (1968).

(37)   Freund, J.  E.,  Livermore, P. E., and Miller, J.,  "Manual
      of  Experimental Statistics." Prentice-Hall, Inc.,
      Englewood Cliffs,  N. J., 1960, 54, 123,  131.

(38)   Kennedy, J. B.,  and Neville, A. M., "Basic  Statistical
      Methods." International Textbook Co., Scranton,  Pa., 1964,
      125, 307, Table A-6.
                               110

-------
                        BIBLIOGRAPHY
Chase, E. S., "Flotation Treatment of Sewage and Industrial
Wastes." Sewage and Industrial Wastes. 30, 6, 783-791 (1958).

Clark, J. W. and Viessman, W., Jr., "Water Supply and Pollution
Control." International Textbook Company, Scranton, Pa., 1965.

Eckenfelder, W. W., Jr., "Industrial Water Pollution Control."
McGraw-Hill Book Co., New York, N. Y., 1966.

Fahlstrom, P. H., "Studies of the Hydrocyclone as a Classifier."
Proceedings of the International Mineral Processing Congress,
Pergamon Press, London, 1963, 87-114.

Harding, J. C., and Griffin, G. E., "Sludge Disposal by Wet
Air Oxidation in a Five MGD Plant." Journal of the Water
Pollution Control Federation, 37, 8, 1134,(1965).

Hay, T. T., "Air Flotation Studies of Sanitary Sewage."
Journal of the Water Pollution Control Federation, 28, 1,
100 (1956).

Kalinske, A. A. and Evans, R. R., "Comparison of Flotation and
Sedimentation in Treatment of Industrial Wastes," in "Flotation
in Waste Treatment," "Biological Treatment of Sewerage and
Industrial Wastes," Reinhold Publishing Co., Inc., New York,
N. Y.  2nd edition, 1958, 222-231.

Marson, H. W. "The Disposal of Sewage Sludge by Combustion
with Special Reference to Fluidization Methods." Journal and
Proceedings, Institute of Sewer Purification, Part 4, 320
(1965).

McGraw, H. A., "The Flotation Process." McGraw-Hill Book Co.,
Inc.,  New York, N. Y., 1918, 81.

McKinley, J. B., "Wet Air Oxidation Process." Water Works and
Wastes Engineering, 2, 19, 97 (1965).

Nemerow, N. L., "Theories and Practices of Industrial Waste
Treatment." Addison-Wesley Publishing Co., Inc., Reading,
Mass., 1963.

Prather, B. V., "Development of a Modern Petroleum Refinery
Waste Treatment Program." Journal of the Water Pollution
Control Federation, 36, 1, 96-102 (1964).
                             Ill

-------
Rebhun,  M.,  and Argaman, W., "Evaluation of Hydraulic Efficiency
of Sedimentation Basins." Journal of the Sanitary Engineering
Division, Proceedings of American Society of Civil Engineers.
91, SA 5, 37 (1965).

Rich, L. G., "Unit Operations of Sanitary Engineering." John
Wiley and Son, New York, N. Y., 1961.

Rich, L. G., "Unit Processes of Sanitary Engineering." John
Wiley and Son, New York, N. Y., 1963.

Simpson, G.  D. and Curtis, L. W., "Treatment of Combined
Sewer Overflows and Surface Waters at  Cleveland, Ohio."  Paper
presented at the 41st Annual Conference Water Pollution Control
Federation,  Chicago, 111., September 23, 1968.

USDHEW, Public Health Service;  "Modern Sewage Treatment Plants,
How Much Do They Cost?" PHS Publication no.  1229,  (1964) 14-28.

USDI, FWPCA; "Storm Water  Runoff From  Urban  Areas, Selected
Abstracts of Related Topics."  (1966).

Van der Kolk, H., "Linking Cyclones  in Series and  Its  Effect
on Total Separation," in "Cyclones in  Industry," Elsevier
Publishing  Co., Amsterday, Holland,  1961  ,  77-88.

Vilentin, F. H. H., "Absorbtion in Gas-Liquid Dispersions:
Some Aspects of Bubble  Technology,"  E. & F.  N.  Spon, Ltd.,
London, England, 1967.

Weibel, S.  R., Anderson, R. J., Woodward,  R. L.,  "Urban Land
Runoff  as a Factor  in Stream Pollution." Journal of  the Water
Pollution Control Federation,  36,  7, 914,  (1964).

Wine, R. L.,  "Statistics for Scientists  and  Engineers."
Prentice-Hall  Inc., Englewood  Cliffs,  N. J., 1964.
                              112

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             SECTION XV


             APPENDICES


A.  Photographs of the Demonstration Plant

B.  The Fort Smith Drainage Area

C.  Construction Costs

D.  Data and Calculations

E.  Typical Data Obtained During Plant
    Shake Down in 1967

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               APPENDIX  A




PHOTOGRAPHS  OF THE DEMONSTRATION PLANT

-------
Two views of the demonstration  pilot plant showing the major  pieces
of equipment.  The visqueen  cover has been removed from  the air-
flotation tank.

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A view of the four  hydrocyclones used  in  the  demonstration pilot
plant.
Comparison  of  different treatments.   The first jar on the left  con-
tains  untreated influent waste;  the  remaining jars contain plant
effluents,  reading left to right,  no chemical treatment, 50 mg/1
Alum,  75  mg/1  Alum, 100 mg/1 Alum,  125  mg/1 Alum, 125 mg/1 Alum +
15 mg/1 Tretolite FR-50, and tap water.   A heavy load
present in  the influent stream.
of blood was

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         APPENDIX B




THE FORT SMITH  DRAINAGE AREA

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     The Fort Smith drainage area is approximately 12,000




acres.  About 10 percent of this total has water-impervious




covers such as streets, parking lots, houses, etc.  The city




proper covers an estimated three-fourths of the area.






     The 1960 U. S. Census listed the Fort Smith population




as 52,991; the 1962 population was 63,309; and the 1968




population of Fort Smith has been estimated in the neighborhood




of 70,000.  The Fort Smith sewer department had an average




of 16,300 non-industrial customers in 1968 and 222 industrial




customers.  Three major industries dispose of their wastes




directly to the Arkansas River.






     Of the nine million gallons of potable water produced




per day, about 70 percent is used for domestic and residential




purposes.  The total daily waste volume of 5.3 million gallons




is treated in two plants - North "P" Street, the location of




the demonstration plant,and Massard Creek.  The Massard Creek




facility provides both primary and secondary treatment for




1.8 million gallons per day of waste estimated to be of 95




percent domestic origin.  The Massard Creek treatment plant




was built as the result of an engineering study submitted to




the City of Fort Smith in 1962.  The plant has a daily capacity




of ten million gallons to provide for future expansion of the




city in the Massard Creek area.  The plant's current flow is




sufficient to operate only one of the two trickling  filters.




There are no sludge treatment facilities other than  a vacuum

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filter; filter solids are buried.






     The North "P" Street treatment plant consists of bar




screens, primary clarifiers, degritters, sludge thickeners




and vacuum filters.  Total daily waste flow averages 3.5




million gallons which is estimated at 77 percent industrial



waste.  The clarifiers have a retention time of one hour and




forty-five minutes and have a design surface loading rate of




700 gallons per square foot per day.






     The sewage collection system in the city consisted of




170 miles of combined and separate sewers as of January 1,




1969.  At that time, there were seven pump stations in operation




with five more in various stages of construction.  Upon




completion of these pumping stations, there will be two sewage




outfalls for the city, one for each of the treatment plants.






     As of January 1, 1969, the City of Fort Smith had no



municipal restrictions or regulations pertaining to sewer




connections or sewage discharge rates and strengths.  The State




of Arkansas Water Pollution Control Regulations are being used



in lieu of city laws.






     The Fort Smith drainage area is described in Table B-l,




and a map of this area is shown in Figure B-l.

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                               TABLE B-l




                   THE FORT SMITH DRAINAGE AREA







The area covers about 36 square miles  and includes:










T 10 N,  R 27 E, Sections 9*.  10, 15, 16*, 21 *, 22




TUN,  R 27 E, Sections 34* in the  State of Oklahoma, and;







T 8 N,  R 32 W, Sections 2,  3, 4, 5*. 8*, 9, 10,  11, 14,  15,  16, 17, 20,




       21,  22,  23,  26, 27, 28, 29, 32,  33, 34,  35




T 9 N,  R 32 W, Sections 21*, 22*,  26,  27,  28, 33,  34, 35 in the State




       of Arkansas .










*Part of the section.
                                   B-3

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       0    I/?
                         I Mile
            SCALE: MILES
              C.I.= EOFT.
THE  FORT  SMITH  DRAINAGE AREA
            FIGURE  B-l

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    APPENDIX C




CONSTRUCTION COSTS

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                    CONSTRUCTION COST RESUME

                             FOR THE
             DISSOLVED AIR FLOTATION DEMONSTRATION
               PILOT PLANT AT FT. SMITH, ARKANSAS
   CONSTRUCTION

   Subcontractor's  Fee:
       Section    I   Civil Work
       Section   II   Mechanical Work
       Section  III   Electrical Work
                    SUBTOTAL:

   Material  Furnished by Rhodes
       Concrete,  Gravel,  Sand
       Reinforcement Steel,etc.
                    SUBTOTAL:

                    I - TOTAL
$ 19,700.00
           $   6,800.00
               8,400.00
               4,500.00
$  1,860.25

$ 21.560.25
                 908.38
                 951.87
II   MECHANICAL EQUIPMENT

    (1)  Flotation Cell

    (1)  Air Dissolving Tank

    (1)  Screen

    (4)  Cyclones

    (1)  Electric Control Panel

    (1)  Motor Control Center

    (2)  Sewage Pumps

    (2)  Chemical Feed Pumps w/100 gal.  tank

    (1)  Air Compressor

    (5)  Mixers

    (7)  Liquid Level  Controllers

    (1)  3-Pen Recorder

    (1)  Instrument  Air  Dryer

    (1)  Flow Meter  w/40" open flow nozzle

    (1) Air  Flow Meter
               9,955.55

               2,948.00

               3,673.00

               4,068.50

               2,401.90

               3,794.00

               2,371.70

               1,408.00

               1,351.00

               1,900.00

               1,175.00

                  453.70

                  107.85

                  814.50

                   99.25
                                C-l

-------
  II  Mechanical  Equipment (Continued)--









  (4)  Slide  Gates                                $    2,210.00




  (9)  Air  Regulators                                    135.00




  (1)  Liquid Level  Gauge                               142.02




  (2)  Temperature  Indicators                         1,046.00




 (24)  Pressure  Indicators                            1,072.77




  (4)  Pressure  Controllers                             357.85




      Electric  Supply Material                       1,856.15




  (I)  Flow Tube                                         343.20




  (2)  Flow Controller                                  102.00




(106)  Valves                                         7,062.85




      Pipe Fittings                                  1,736.13






                       II TOTAL   $ 51,585.79









                          GRAND TOTAL     $ 73,146.04
                             C-2

-------
     APPENDIX  D




DATA AND CALCULATIONS

-------
    Influent  pH  During  Dry  Weather
        3.2                 1
        6.2                 1
        6.4                 2
        6.5                 4
        6.6                 7
        6.7                 5
        6.8                12
        6.9                 5
        7.0                26
        7.1                18
        7.2                10
        7.3                11
        7.4                 3
        7.5                 2
        7.8                 1
        8.3                 1
        8.7                 1

           TOTAL         110
        X   =   7.0

        S   =   0.3

        Median  =   7.0


 95% Confidence Interval

     6. 9 <  M   ±1.1

 X = Sample Arithmetic  Mean

 S =  Standard Deviation

M. -  True Population Arithmetic Mean
                   D-l

-------
   Influent  Turbidity During  Dry Weather
 Turbidity
  Jackson Units                       £

 500 - 549                             1
 450 - 499                             1
 400 - 449                             1
 350 - 399                             3
 300 - 349                             7
 250 - 299                             6
 200 - 249                            26
 150 - 199                            17
 100 - 149                            33
  50 -  99                            10
   0-49                             8
                  TOTAL              113
 X  =   180  J.U.

 S  =   99 J.U.

 Median  =   177 J.U.


 95% Confidence Interval (37)

    178 * M  £ 182


 X = Sample Arithmetic Mean

 S  = Standard Deviation

Jil  - True Population Arithmetic Mean
                      D-2

-------
        Influent Suspended Solids and Volatile Suspended Solids Concentrations
        During Dry Weather
        Suspended Solids
        mg/1
                       Volatile Suspended Solids
                       mg/1           f


900-999
800-899
700-799
600-699
500-599
400-499
300-399
200-299
100-199



3
1
3
2
4
2
20
34
25

350
325
300
275
250
225
200
175
150
125
100
75
2
3
0
1
8
11
5
9
4
2
0
4
       TOTAL
112
TOTAL
49
       X = 272. 3 mg/1

       S = 201 mg/1

       Median = 239 mg/1

       95% Confidence Interval

         269.  7 £ JLL  ^ 274. 9
                       X = 195. 1 mg/1

                       S= 14.5 mg/1

                       Median = 202 mg/1

                       95% Confidence Interval

                       194. 0 £JUL  ± 196. 2
The table does not include suspended solids for two isolated events during which
the concentrations were 1297 mg/1 and 1140 mg/1.
                                 D-3

-------
    Influent  BOD Concentrations  During Dry Weather


320
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
0
BOD
mg/1
- 339
- 319
- 299
- 279
- 259
-239
- 219
- 199
- 179
- 159
- 139
- 119
- 99
- 79
- 59
- 39
- 19
      TOTAL
 1
 2
 4
 4
 6
 5
 3
10
 9
11
 7
 1
 3
 2
 3
 4
 1

76
      X  =   174.5 mg/1

      S  =   75.8  mg/1

      Median  =   174 mg/1


      95% Confidence Interval

        168.3 ±JUL  ± 180.7
 X = Sample Arithmetic Mean
 S = Standard Deviation
JH = True Population Arithmetic Mean
                          D-4

-------
       Influent Total Solids and Total Volatile Solids Concentrations During
       Dry Weather
             Total Solids
                                                  Total Volatile Solids
mg/1
900-999
800-899
700-799
600-699
500-599
400-499
300-399
200-299
100-199

TOTAL
F
5
8
8
17
17
8
1
2
3

69
mg/1
601-650
551-600
501-550
451-500
401-450
351-400
301-350
251-300
201-250
151-200
TOTAL
F
1
1
1
1
5
10
11
7
7
3
47
       X = 621. 0 mg/1
       S = 189. 5 mg/1
       Median = 623 mg/1
       95% Confidence Interval
         617. 8^JJ  1 624.2
X = 348. 9
S =  18. 8
Median = 340
95% Confidence Interval
   347. 7 ±JJL £ 350. 1
The table does not include total solids for several isoladed events in which
concentrations were as high as 2136 mg/1.


       X = Sample Arithmetic Mean

       S =  Standard Deviation

      JU. = True Population Arithmetic  Mean
                                   D-5

-------
   Total Influent  Phosphate  Concentration During

                      Dry Weather
     Total Phosphate
           mg/1
                                    2
                                    2
                                   11
                                   13
                                    9
                                   15
                                   21
                                    6
                                    2
      TOTAL                        81
80
70
60
50
40
30
20
10
0
- 89
- 79
- 69
- 59
- 49
- 39
- 29
- 19
9
     X  =   39.8  mg/1

     S  -   25.5  mg/1

     Median   »   38 mg/1


      95% Confidence Interval

       38.7 ±JUL * 40.9


 X = Sample Arithmetic Mean

 S = Standard Deviation

JLl = True Population Arithmetic Mean
                           D-6

-------
      Influent  Total  Nitrogen  During  Dry Weather
      Total Nitrogen
           mg/1
                                              1
                                              0
                                              2
                                              2
                                              6
                                             22
                                             20
                                              9
                                              2
                                              8
                                              4
                                              4
                                              2
                                              2
                        TOTAL                84
30.
28.
26.
24.
22.
20.
18.
16.
14.
12.
10.
8.
6.
4.
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
0 -
31.9
29.9
27.9
25.9
23.9
21.9
19.9
17.9
15.9
13.9
11.9
9.9
7.9
5.9
      }T  =   17.7 mg/1

      S  =   5.0 mg/1

      Median   =  19.3  mg/1


       95% Confidence Interval

        17.Z ±M  ± 18.2


 X = Sample Arithmetic Mean

 S = Standard Deviation

M - True Population Arithmetic Mean
                             D-7

-------
            Influent pH  During Storm Events
                          PH
                          7.4
                          7.3
                          7.3
                          7.3
                          7.2
                          7.2
                          7.0
                          7.0
                          7.0
                          6.9
                          6.9
                          6.9
                          6.8
                          6.7
                          6.6

              TOTAL      1055
         T  =  7.0

         S  =  0.2

         Median  =   7.0


          95% Confidence Interval

               6.8 *M  ± 7.2


 X = Sample Arithmetic Mean

 S = Standard Deviation

JLL - True Population Arithmetic Mean
                           D-8

-------
      Influent  Turbidity  During Storm Events
                     Turbidity
                    Jackson Units

                        340
                        332
                        326
                        252
                        238
                        238
                        230
                        223
                        210
                        210
                        210
                        192
                        186
                         50
              TOTAL    3237
  X   =   231 J.U.

  S   =   73 J.U.

  Median  =  226

  95% Confidence Interval

        226 ±11  ± 236




 X = Sample Arithmetic Mean

 S = Standard Deviation

jLL = True Population Arithmetic Mean
                           D-9

-------
Influent Suspended Solids and Volatile Suspended Solids Concentrations
During Rain Events
      Suspended Solids
         og/1

       987

       788

       775

       730

       665

       520

       484

       438

       425

       405

       386

       385

       377

       329

       317
Volatile Suspended Solids
       mg/1

       377

       333

       333

       282

       263

       231

       220

       144
       X = 534 mg/1
       S = 197 mg/1
       Median = 438 mg/1
       95% Confidence Interval
        526 ±JUL  = 542
       X = 273 mg/1
       S =  75 mg/1
       Median =272
       95% Confidence Interval
         387 =>U = 405
       X = Sample Arithmetic Mean
       S = Standard Deviation
      M. - True Population Arithmetic Mean
                          D-10

-------
    Influent BOD  Concentrations  During Rain  Events
                          BOD
                          mg/1

                          440
                          282
                          245
                          242
                          202
                          202
                          200
                          190
                          165
                          160
                          148
                          147
                          139
  X  =   212 mg/1

  S  =    80.8  mg/1

  Median   =  200 mg/1

  95% Confidence Interval

     207 ±J1< £ 217
 X = Sample Arithmetic Mean
 S = Standard Deviation
Jd = True Population Arithmetic Mean
                           D-ll

-------
Influent Total Solids and Total Volatile Solids Concentrations During
Rain Events
       Total Solids
       mg/1

       1282

       1216

       1190

       1073

       1061

        929

        820

        812

        777

        777

        753

        750

        721

        677

        647

        602

X = 880 mg/1
S = 209 mg/1
Median = 794 mg/1
95% Confidence Interval
       872 ±JLL ± 888

       X = Sample Arithmetic Mean
       S = Standard Deviation
      ~U- = True Population Arithmetic Mean
Total Volatile Solids
mg/1

588

410

410

406

360

303

294
X = 396
S =  98
Median = 406
95% Confidence Interval
    387 ^ JUL   ± 405
                         D-12

-------
        Influent  Total Phosphate Concentrations

                  During Rain  Events
                         Total
                        Phosphate
                          mg/1

                           68
                           50
                           35
                           29
                           26
                           24
                           24
                           24
                           23
                           21
                           18
                           17
                           16
                           12
   X  =  2 7..6  mg/1

   S   =   14.3 mg/1

   Median =  24 mg/1

   95% Confidence Interval
       25.4 £ JLL  ± 29. 8


 X = Sample Arithmetic Mean

 S = Standard  Deviation

JU. = True Population Arithmetic Mean
                           D-13

-------
        Influent  Nitrogen During  Storm Events
                   Nitrogen
                    mg/1

                    25.2
                    24.0
                    21.8
                    20.3
                    17.9
                    17.9
                    15.7
                    15.4
                    14.8
                    14.2
                    13.8
                    11.4
                    10.4
                     8.2
           TOTAL   231.0
      T  =  16.5  mg/1

      S  =  5.4 mg/1

      Median  =   15.6 mg/1

      95% Confidence Interval
         15.2 ± JUL  ± 17.8


 X = Sample Arithmetic Mean

 S = Standard Deviation

AL = True Population Arithmetic Mean
                           D-14

-------
                           CALCULATIONS

  Computations of the  mean removal rates of suspended solids,

  BOD, total solids,  total phosphate and total nitrogen during

  rain events using various chemical treatments.  All mechanical

  equipment on stream.



Waste Flow Rate    =   350  GPM

 AP                =    50  psi

Air Feed Rate      =    30  cfm
95% confidence interval  was  calculated using values of  "t"  found
in Table II in the Manual  of Experimental Statistics  (37).
     /(X-X)2
                            Where
                            X  =  Removal Rates
                            X~  =  Mean Sample Removal Rate
                            01  =  Mean Population Removal Rate
                            n  =  Number of Observations
                     X  -  t   S.   -s  P  ;=  t  S.  +  x
                           Krf              {ri
                                D-15

-------
                       Suspended Solids Removal- During

               Rain Events Using No  Chemical Treatment
X
79
71
56
206
69
X-X
10
2
-13

(X-X)
100
4
169
273
    X" = 69
                                       =   11.7


                        If  Q  ^   4.303,  Reject 56 **

                        t  =  13(1.732)   =  1.924  cannot reject  56
                                11.7
69 - 4.303(11.7)
      1.732

   69 - 29.1  *

   39.9  ±  »  ±
                                  ±  4.303(11.7)  +  69
                                        1.732

                                 69  +  29.1
                            98.1
**  Application of Chauvenet's Criteria;  critical values found
in Table A-6, Basic Statistical Methods.  /OON
                                          (.JO)
                                    D-16

-------
  309
   62
        X-X
   85      23    529
   71       9     81
   66       4     16
   44      18    324
   43      19    361
                Suspended Solids Removal During Rain Events

                           Using Alum Only
             (X-X)2
             1311
                               S = ,1311  =  18.1
If  t  >.   2.571,  Reject 43 *

t  =  19 ^  =   2.35
      18 .1

   Cannot  Reject  43




If t  ^  2.571,  reject 85

t  =  23	|(F  =   2.841
      18.1

Reject 85
        X-X
 224
  56

  X  =  56
             (X-X)2
71     15    225
66     10    100
44    -12    144
43    -13    169
             638
                                  S  -»/ 6^8
                                        3
 If  t

 t  = 15
                                  16.03
   ••  16.03


2.776, Reject  71

  = 1.871, Cannot  Reject 71
             56  -   2 .776(16.03)
                          2
                                            ^  2.776(16.03) +  56
                                                      2
                    56 - 22.2  ^  p.  4.   56  + 22.2

                      33.8  ^  /i     78.2
11 Application of Chauvenet's  Criteria; critical  values found in
'able A-6,  Basic Statistical Methods.
                                   D-17

-------
                    Suspended Solids Removal During

              Rain  Events  Using Alum and Tretolite   (Continued)
      X-X   (X-X)2
 85     3     9
 85     3     9                 S  - \j 71  = If 17.75   =   4.213
 84     2     4                         4
 82     0     0
 75    -7    49                If  t  ^. 2.776,  reject 75 **
411          71
 82                            t  =  7	/5~ =   3.727,    Reject 75
                                      4.2
  X   X-X  (X-X)
 85     1     1
 85     1     1                 S  =\fT  =/~2  =   1.414
 84     0     0                       3
 82    -2	4
336                            If t  i.  3.182, Reject  82 **
 84
                               t  - 2 \/4"   =  2.828
                                    1.414           Cannot  Reject 82
      84 ;  S  -  1.414
X  =  t s  ^  p  4.  X + Ju	s_
       n                 n

84 - 3.182(1.414)   £  /i   ±  84 + 3.182(1.414)
          2                              2

84 - 2.25  ^  ju  ^  84 + 2.25

  81.75  ^  ju  ^  86.25


 ** Application  of  Chauvenet's  Criteria;  critical values found in
   Table A-6, Basic Statistical Methods.
                                D-18

-------
              Suspended Solids Removal During Rain Events

                   Using  Alum and Tretolite
     X-X
(X-X)
85
85
84
82
75
75
74
66
626
78

X
85
85
84
82
75
75
74
560
80

X
85
85
84
82
75
75
486
81
7
7
6
4
- 3
- 3
- 4
-12



X-X
5
5
4
2
-5
-5
-6



X-X
4
4
3
1
-6
-6


49
49
36
16
9
9
16
144
328

— 2
(X-X)
26
25
16
4
25
25
36
156

— 2
(X— X)
16
16
9
1
36
36
114

                                    328  =  \/46.86
                                     7
                                           6.85
                              If t  ^  2.365,  Reject 66  **

                              for X =  66,  t   = 12 i/T = 4.95
                                                6.85
                              Reject  66
                                  = /  156   = \/2T  =  5.099
                             If t  ^  2.447,  Reject 74   **

                             for X = 74,  t  =  6  iTf  =   3.116
                                                 5.1
                               Reject 74
                                S   = \/114 = \/22.8   -   4.775
                                       5
                                If  t ^  2.571, Reject  75  **
                                for X = 75 ; t


                                Reject 75
                                     6 \/6~
                                     4 .8
2.811
**  Application of Chauvenet's Criteria;  critical values found  in
Table  A-6,  Basic Statistical Methods.
                                 D-19

-------
          ONE  WAY  ANALYSIS  OF VARIANCE

SUSPENDED SOLIDS REMOVAL DURING RAIN EVENTS

Rain Events
No Chemicals
Alum
Alum + Tretolite

Totals

T = 766
2
r. . T2 = (766)
N"~ 11
SSB= s: T±2 - C
n
2
i
SSE= SST - SSB =
MSB= SSB = 1572
k-1 2

MSE= SSE - 6542
N-k 8
F - MSB - 0.96
MSE
T T 2 X 2
Ti Ti Xi
206 42436 14418
224 50176 13182
336 112896 33855

766 205508 61455


- 586756 - 53341
11
54913 - 53341 - 1572

61455 - 53341 - 8114

8114 - 1572 = 6542
- 786


- 817.75



n T12/n
3 14145
4 12544
4 28224

11 54913




Source of
Variation

Between
Samples
Error


Total




X
79 k =
56 k-1
84 N -
	 N-k
CX - C
F



Degrees of
Freedom


2
8


10




                                                               3
                                                               -  2
                                                               11
                                                               -  8
                                                             0.05
                                                              4.46
                                                                  Sum  of
                                                                  Squares


                                                                   1572

                                                                   6542


                                                                   8114
Mean
Squa


 786

 818
                          D-20

-------
                        TABLE  D-l






     One way analysis  of  variance  of  suspended solids removal




during rain events using  various  chemical  treatments.  All




mechanical equipment on stream.   Chemical  treatments include




(1) no chemicals,  (2)  alum  only,  and  (3)  alum plus Tretolite




Fr-50.




Null Hypothesis




HQ:  There is no significant  difference  between the mean rates of




TSS removal for the modes of  operation  listed above.









Alternate Hypothesis




Ha:  There is a significant difference  between the mean rates of




Suspended Solids removal  for  the  modes  of  operation listed above.







**•   = 0.05






Fot  = 4.46








Criteria:  Reject  HQ if F >• F   ,  reserve  judgement if F <   Fo«,






Result:  F  =  0.134




Decision:  F is less than F oe. ,  therefore cannot reject HQ .




There is no apparent significant  difference between the mean




suspended solids removal  rates  for the  modes of operations listed




above.




     To determine  where the difference  between these mean exists,




a modified version of  Duncan's  Multiple  Range Test  (39) was used.
                           D-21

-------
 119
       X-X
39.7
 X = 40
               BOD Removal During Rain Events

                  Using No Chemical Treatment
(X-X)2
  69    29    841
  35-5     25
  15   -25    625
1491
1491
                              =  \/745.5
                              80   *
                    27.3
                T.S. Removal During Rain Events

                  Using No Chemical Treatment
   X   X-X  (X-X)2
45
29
29
103
34.3
X =
11
- 5
- 5


34
121
25
25
171


                                                      9.25
                      34.3 - 9.25(4.303)  ±  ju  ^  34.3 + 9.25(4.303)
         34.3 - 23.0
                                         £.  34.3  +  23.0

                                        57
 *  95% confidence interval obtained from Table V, Manual of
 Experimental Statistics.
                                D-22

-------
                      BOD Removal During

                  Rain Events Using Alum  Only
      X-X
       (X-X)2
 59      23    529
 31     -4     16
 30     - 5     25
 20     -15    225
139
795
34.75
X = 35
                         s  • 1/795  = 1/265  =  16.3
                             '  3

                         Reject 58 if  Q  i.  1.53
                                                           **
                                   23    =   1.41,  Cannot Reject 58
                                  16.3
35 - 16.3(3.182)
                     35  + 16.3(3.182)
 35  - 25.9  ^  u  -j.  35 +  25.9

         9  ^  ju  ^  61
 I
36
                      T.S.  Removal  During

                 Rain Events  Using  Alum Only
X
48
36
35
23
142
X-X
12
0
- 1
-12

(X-X)2
144
0
1
144
289
35.5
                                              17. = 9.82
                                               3
                 35.5 - (9.82) (3.182)
                            \TT
                                                    ^  35.5 +  (9.82) (3.182)
                        35.5  -  12.4
                              23
                                       35.5 +  12.4
                                    48
 **   Application of Chauvenet's Criteria,  critical values found in
 Table  A-6,  Basic Statistical Methods.
                                D-23

-------
                 BOD Removal During Rain  Events

                    Using Alum + Tretolite
      X-X   (X-X)2
X
82
77
74
72
70
64
439
X-X
9
4
1
- 1
- 3
- 9

(X-X)2
81
16
1
1
9
81
189
73
 82     14    196
 77      9     81                    	     	
 74      6     36              S  =  v/1438  - \|239.7  =  15-5
 72      4     16                      6
 70      2      4
 64    - 4     16              Reject  35  if Q  ;>  1.80 **
 35     33   1089
474	1438              Q  =  .33	  -  2.13,  Reject 35
67.7                                 15.5
                               S   -  ,189    \D7.8  = 6.15
                          73 -  6.15(2.571)   ^  ju  ^  73 + 6.15(2.571)
     73                            rg"                        vTg-

                          73 -  6.5  ^ »  ^  73 + 6.5

                          67  ^ ju  ^  79
 **  Application of Chauvenet's Criteria,  critical values found in
     Table A-6, Basic Statistical Methods.
                                 D-24

-------
  ONE WAY ANALYSIS  OF  VARIANCE




BOD REDUCTION DURING RAIN EVENTS
                        n
/n
No Chemicals
Alum
Alum + Tretolite
Tot

C =
SSB
SST
SSE
MSB


MSB

F -

als

T2 -
N
• Z-
= SST
" SSB
k-1

" SSE
N-k
MSB
MSB


(697)2
13
i! - c =
n
.2 - C =
- SSB =
- 4300
2

= 2474
10
= 2150
247
119 14161 6211
139 19321 5624
439 192721 32309
697 44144

= 485809 = 37370
13
41670 - 37370 = 4300
44144 - 37370 = 6774
6774 - 4300 - 2474
= 2150


= 247

= 8.70

3 4720
4 4830
6 32120
13 41670


Source of
Variation
Be tween
Samples
Error


Total




40 k = 3
35 k - i = 2
73 N = 13
N\r — TO
— K — -LU
ex - 0.05
F = 4.10

Degrees of Sum of
Freedom Squares
2 4300
10 2474


13 6775







Mean
Square
2150
247







                D-25

-------
                   DUNCAN'S MULTIPLE RANGE TEST (39)
                           (MODIFIED VERSION)
                  BOD REDUCTION DURING RAIN EVENTS
1.      Alum
2.      Alum + Tretolite
                           X
                           35
                           73
      .=/ (MSE)2  _= 1(247) 2  =Y49.4   =  7.05
                        10
    =  0. 05; N   = 10
                           r  & r  = Sample Sizes
                            1    2
P = 2
SSR
LSR =
(SSR)S-
x
3. 15
22.21
Ranked Means
Means
201
1.
2.
Sv =,i
Diff
P
1
35
LSR
38 2 22.2
No Chemicals
Alum + Tretolite
(MSE)2 =/
(247) 2
2
73
De
X
40
73
= 1
                           Decision:  Difference is significant.
                     9
                           r  & r? = Sample Sizes
     = 0. 05; N  = 10
              Lt
P = 2
SSR
LSR =
(SSR) S-
.X.
3. 15
23. 31
Ranked Means 1
40
Means
201
Diff
33
P
2
LSR
23.3
2
73
- r
                           Decision:  Difference is significant.
                                   D-26

-------
                   DUNCAN'S MULTIPLE RANGE TEST
                          (MODIFIED VERSION)
                 BOD REDUCTION DURING RAIN EVENTS

1.
2.
s,-r =,,

Alum
No Chemicals
/ (MSE) 2 =1(24
X
35
40
7) 2
      rl + r2
                           r, & r  = Sample Sizes
                             •*•    £A
   = 0. 05; N  = 10
P = 2
SSR
T GT3 — fQCt?\C;
j_joxv — ^ oo x\ /OY
3. 15
26.46
Ranked Means
1 2
35 40
Mean
201
Diff
5
P
2
LSR
26.5
                            Decision:  Difference is not significant.
                                     D-27

-------
                    DUNCAN'S MULTIPLE RANGE TEST

                         (MODIFIED VERSION)

                 BOD REDUCTION DURING RAIN EVENTS
1.
2.
Alum
Alum + Tretolite
             J(2150)2
                     10
      0.05; N2  =  10
P  =  2
SSR
LSR =
(SSR)S-
A
3.15
65.33
Ranked Means
                  1
                 35
Means
201
Diff
38
P
2
LSR
653
 X
35
73
  V43~0
                             rl & r2
 2
73
                                       20.74
                                      Sample  Sizes
                             Decision:   Difference  is  not  significant
1.  No Chemicals
2.  Alum + Tretolite
S-  =  (MSE)2
             tf (2150)2
             '    9
      0.05; N2  =  10

      2
                         X
                        40
                        73
SSR
LSR =
Ranked
(SSR)S-
3.15
68.86
Means
1
40
Means
2-1
Diff
33
P
2
LSR
6886
   1/3 V4300   =   1/3   (65.57)


   r-, &  r_  =  Sample  Sizes
21.86
                                2
                               73
                              Decision:   Difference is  not significant
                               D-28

-------
1.   Alum
2.   No Chemicals
                    DUNCAN'S MULTIPLE RANGE  TEST

                         (MODIFIED VERSION)

                  BOD  REDUCTION DURING RAIN  EVENTS
 X
35
40
     i/ (MSB) 2  =  .[(2150)2  =i/655.7   =   24.79
     V n+ ro     V    7
                                          r2   =  Sample Sizes
      0.05;  N2
10
1 2
Ranked Means 35 40
Means
2-1
Diff
5
P
2
LSR
78.1

                              Decision:   Difference is not  significant,
                               D-29

-------
                       TABLE D-2




     One way analysis of variance for BOD reduction during rain




events using various chemical treatments.  All mechanical equip-




ment on stream.  Chemical treatments include  (1) no chemicals,




(2) alum only, and (3) Alum plus Tretolite FR-50.




Null Hypothesis




HQ:  There is no significant difference between the mean rates of




BOD reduction for the modes of operation listed above.




Alternate Hypothesis




Ha:  There is a significant difference between the mean rates of




BOD reduction for the modes of operation listed above.






ex:       =  0.05






Foe      =  4.10




Criteria:  Reject H  if F > F    , reserve judgement if F £   Foe






Result:  F  =  8.70




Decision:  F is greater than F«:  , therefore reject HQ.  There is




an apparent significant difference between the mean rates of BOD




reduction as listed above.




     The application of a modified version of Duncan's Multiple




Range Test indicates that a difference exists between the mean re-




duction rate of BOD when alum and Tretolite FR-50 are used and




the other treatments.
                            D-30

-------
      Total Solids Removal During Rain Events

     Using Alum  +  Tretolite FR-50
                           538 = \tf6.9  =   8.77
                51.7  -  8.77(2.447)  ^  ;u  ^  51.7  + (8.77) (2.447)
                                                        s/T
                51.7  -  8 .5  4.  jn  ^  51. 7 +  8.5

                43      ^      60
     Total Phosphate  Removal During

Rain Events  Using  Alum + Tretolite FR-50
X
100
91
83
81
58
53
52
513
X* -
X-X
26
17
9
7
-16
-21
-22
74
(X-X)2
676
289
81 S = ./2276 - J/379.3 = 19.47
49 6
256
441 74 - (19.47) (2.447) ^ ju ^ 74 + (19 . 47) (2 . 447 )
484 VT~ V 1
2276
74-18 ^ u ^ 74+18
56 ^ p ^ 92
                   D-31

-------
                           ONE WAY ANALYSIS .OF VARIANCE

                      TOTAL SOLIDS REMOVAL DURING RAIN EVENTS
Ti Ti2
No Chemicals 103 10609
Alum 142 20164
Alum & Tretolite FR-SO 362 131044
TOTALS 607
T = 607
C - T2 = 6072 = 368449 = 26318
J~ 14 14
SSB =y Ti - C = 27298 - 26318 = 980
n
SST -SIZIXi2 _ c - 28319 - 26318 = 2001
SSE - SST-SSB = 2001 - 980 = 1021
MSB - SSB = 980 = 490
k-1 2
X 2
3707
5354
19258
28319
Source of
Variation
Be tween
Samples
Error
Total
T 2 /
n TI /n
3 3536
4 5041
7 18721
14 27298
Degrees of
Freedom
2
11
13
X

34 k = 3
36 k-1 = 2
52 N - 14
N-k = 11
F
Sum of
Squares
980
1021
2001
.05
= 3.98
Mean
Square
490
92.8
5.28
MSB - SSE , 1021 = 92.8
    MSB - 490
    MSB   92.8
5.28
                                          D-32

-------
                       TABLE D-3




   One way analysis of variance of total solids  removal  during




rain events using various chemical treatments.   All mechanical




equipment on stream.  Chemical treatments include:   (1)  no




chemicals; (2) alum only; (3) Alum plus Tretolite FR-50.




Null Hypothesis




H0:  There is no significant difference between  the mean rates




of total solids removal  for the modes  of operation  listed above.








Alternate Hypothesis




H :  There is a significant difference between  the  mean  rates  of
 3



total solids removal  for  the modes of  operation  listed  above.






 «*•        =  0.05




F-c        =  3.98






Criteria:  Reject H   if  F > F    ,  reserve judgement if  F <    F«






Result:  F   =   5.28






Decision:  F is greater  than  Foe  ,  therefore reject HQ .   There




is a significant difference  between  the  mean rates  of Total Solids




removal  during rain  events.






   An analysis using  a modified  version  of  Duncan's Multiple




Range Test indicates  the difference  exists  between  the  mean




removal  rate of  total solids  when alum and  Tretolite FR-50 is




used and the other  treatments.
                           D-33

-------
               Total Phosphate Removal During

                 Rain Events Using Alum Only
X
48
11
59
X-X
18.5
-18.5

(X-X)2
342.25
342.25
684.5
29.5
                                    V684.5
26.16
                                              71 *
X « 30
* 95% confidence interval obtained from Table V, Manual of
Experimental Statistics.
                                D-34

-------
         Total Phosphate  Removal During  Rain  Events

                 Using No Chemical  Treatment
 83
 12
 95
      X-X
       (X-X)2
 35.5
-35.5
1260.25
1260.25
        2520.5
 47.5

X  =  48
S  = V 2520.5  =  50.2
                                          80 *
          Total  Nitrogen  Removal  During Rain Events

                  Using  No Chemical  Treatment

  X  X-X    (X-X)2

                               S
10
4
1
0
15
6
0
3
4

36
0
9
16
61
3.75
                            i/61   = V 20.3   =   4.51
                                                50%  *
*  95% confidence interval obtained  from Table V,  Manual  of
Experimental Statistics.
                               D-35

-------
              Total Nitrogen Removal During

        Rain Events Using Alum + Tretolite FR-50
  Total Nitrogen
      mg/1
X
15
12
10
8
0
0
0
45
— o • —
x-x
8.6
5.6
3.6
1.6
6.4
6.4
6.4

(X-X)2
73.96
31.36
12.96
2.56
40.96
40.96
40.96
243.72
6.4
                                0 %
                                    =   y60.7


                                    <£  45%
                                                          7.79
Suspended Solids removal during an isolated rain event using alum
+ Tretolite FR-50, waste flow rate » 200 GPM, p = 50 psi, air feed
rate =25 cfm.
Suspended Solids
       mg/1
In       Out      %R
775
79
90
Suspended solids removal during an isolated rain event using 150
mg/1 lime and 5 mg/1 Drew Floe 410 waste flow rate =350 GPM,
p=50 psi, air feed rate =30 cfm.
Suspended Solids

In	Out	  % Removal
220
175
    21
* 95% confidence interval obtained from Table V, Manual of
  Experimental Statistics.
                           D-36

-------
       ONE WAY  ANALYSIS OF VARIANCE




TOTAL PHOSPHATE REMOVAL DURING RAIN  EVENTS
It V
Su'11"1"1' H IHI llll
Alum + Tretolite FR-50 518 268325 40608
Totals 672 50066
T = 672
C - T2 = 6722 = 451584 = 41053
N 11 11
SSB - T±2 - C • 44584 - 41053 = 3531
n
SST =52X.2 - C - 50066 - 41053 - 9013
SSE = SST - SSB = 9013 - 3531 - 5482
MSB = SSB = 3531 = 1766
k-1 2
MSE - SSE = 5482 = 685
N-k 8
F - MSB - 1766 = 2.58
MSE 685
n Ti2/n X
2 4512 48 k - 3
2 1740 30 k - 1 - 2
7 38332 74 N = 11
N- V = 8
— K. ^ o
11 44584 ex = 0.05
F = 4.26



Source of Degrees of Sum of
Variation Freedom Squares

Between
Samples 2 3531
Error 8 5482

Total 10 9013









Mean
Square

1766
685






                      D-37

-------
                        TABLE D-4






      One way analysis of variance for the removal of total




phosphates during rain events using various chemical treatments.




All mechanical equipment on stream.  Chemical treatments include




(1) no chemicals, (2) alum only, and (3) alum plus Tretolite




FR-50.




Null Hypothesis




HQ:  There is no significant difference between the mean rates  of




total phosphate removal for the modes of operation listed in




Table 4.






Alternate Hypothesis




H :  There is a significant difference between the mean rates of
 a



total phosphate removal fro the modes of operation listed in




Table 4.









 00          =  0.05






Foe           =4.26






Criteria:  Reject HQ if F •>• F   , reserve judgement if F <    F«.








Result:  F   =   2.58









Decision:  F is less than F«*  , therefore reserve judgement.




There is no significant difference in the TS removal rates  during




rain  events.
                           D-38

-------
      Computations of The mean rates  of  suspended  solids ,

BOD, total solids, total phosphate, and  total  nitrogen  removal

using The various combinations of  the  screen,  cyclones  and

flotation cell.
Waste Flow Rate   =   350 GPM

 AP               =    50 psi

Air Feed Rate     -    30 cfm



95% confidence interval was  calculated  using  values of  " t " found

in Table II in the Manual of Experimental  Statistics.

      n-1                   Where
                            JC   =   Removal Rates
                            It   =   Mean Sample Removal Rate
                            n   =   Number  of  Observations
                            M   =   Mean Population Removal Rate
      X - t  _s_ ^ ju   ^   t_s_    +X
             /n"       ~
                            D-39

-------
Removal of Suspended Solids Using Screen and Flotation Tank
X
58
49
48
48
41
244
X-X (X-X)2
9
0
- 1
- 1
8
Totals
81
0
1
1
64
147
49
 49 - 6.06(2.776)
         5
49-7.5

41.5  ^
          ju
                                                    6.06
                                                49 + 6.06(2.776)
                                                           5
ju   ^  49 + 7.5

z   56.5
                           D-40

-------
             Removal of Suspended Solids Using Screen,

               Primary Cyclone  and  Flotation Tank
       X-X    (X-X)2
  60     11     121
  55      6      36              S   =\j 399 =  19.975   =   7.5
  53      4      16                     7      2.646
  52      3       9
  51      2       4    49 -  (2.365) (7 .5)  ^  >u  ^  49 +  (2.365) (7.5)
  42     -7      49           /3~
  41     -8      64
  39    -10     100       49  -  6.3   ±  ju.  ^  49 +  6.3
 393  Totals    399
49.1                      42.7   ^   ja  ^  55.3
 X  =  49
                                 D-41

-------
             Removal of Suspended Solids Using Two Secondary

                  Cyclones  and Flotation Tank
_X	X-X   (X-X)2
 67      24           S = \/21  -  4.583   - 3.24
 66      1     1                 2     1.414
 61    - 4    16
194	2_1           64.7 - 3.24(4.3)   <  fi  <  64.7 +  3.24(4.3)
64.7                                 V3~                         VT

                           64.7 - 8.0  ^ »   <  64.7 + 8.0
 X  =  65
                           56.7  ^  ju  ^  72.7
                                 D-42

-------
            Removal of Suspended Solids Using Screen,

          Three  Secondary Cyclones and  Flotation Tank
      X-X     (X-X)2
 60      7      49
 59      6      36
 54      1       1               S = J202  =  14.213 = 6.35
 53      0       0                      5      2.236
 49      4      16
 43     10    100       53 - (6.35) (2.571)   *.  p  ^  53 + (6.35) (2.571)
318 _ 202               6                               6
 53
                          53-6.7  ^  /u  ^  53 + 6.7

 X  =  53                 46.3     ju      59.7
                                D-43

-------
                       ONE WAY ANALYSIS OF VARIANCE
   SUSPENDED SOLIDS REMOVAL  USING  VARIOUS COMBINATIONS OF SEPARATORY  EQUIPMENT
                                                     n
Screen
Screen &
Screen &
Screen &
TOTALS
T = 11
C = T2 =
N
ll
SSB - 2,


SST - 2
SSE -
MSB -
MSB -

244
Primary Cyclone 393
3 Secondary Cyclones 318
2 Secondary Cyclones 194

49
(1149)2
22

3' - c
n

c v 2 r
> X-JL - L
SST - SS
SSB =
k-1
SSE -
N-k
1149

- 1320201 = 60009
22

= 60612 - 60009 - 603


= 61348 - 60009 = 1339
B = 736
603 - 201
3
736 = 40.9
18
59536 12054 5
154449 19703 8
101124 17056 6
37636 12535 3
61348 22



Source of
Variation

Between
Samples
Error
Total


11907 49
19306 49
16854 53
12545 65
60612



Degrees of
Freedom


3
18
21


k = 4
k-1 - 3
N = 22
N-k = 18
— — _. - _ r\ r\ c
cXi = U . U j
F = 3.16



Sum of Mean
Squares Square


603 201
736 40.9
1339


MSB  -  201  -  4.91
MSE     40.9
                                     D-44

-------
                    DUNCAN'S  MULTIPLE RANGE TEST

                          (MODIFIED VERSION)

 SUSPENDED SOLIDS  REMOVAL USING VARIOUS COMBINATIONS OF SEPARATORY
                           EQUIPMENT


Non-Rain Events

1.  Screen, primary cyclones,  flotation cell
2.  Screen, 3  secondary  cyclones, flotation cell
Sx
(MSE)2
rl+r2
\/ (40.9)2
     14
5.843  =  2.42
                                       r2  =  Sample sizes
      0 .05 ;
            18
P  =  2
SSR
LSR = (SSR)S-
X
2.97
7.19
1 2
Ranked Means 49 53
Means
B-A
Diff
4
P
2
LSR
7.19

                              Decision:  The difference between  the
                                         mean removal  rates  is not
                                         s ignifican t.
                                D-45

-------
                   DUNCAN'S MULTIPLE RANGE  TEST

                        (MODIFIED VERSION)

Suspended solids removal using various combinations  of  Separatory
equipment.

Non-Rain Events
                                                    X
1.  Screen, flotation cell, 3 secondary  cyclones    53
2.  Screen, flotation cell, 2 secondary  cyclones    65
S-  =  (MSE)2  ^\/(40.9)2  =  (2 . 13) (1. 414)
         +r     \T   9
.05;  N2
                  18
                                  rl  &  r2
                                          3.014
                                         Sample  sizes
SSR
LSR

= (SSR)S-
A
2.97
8.95
1
Ranked Means 53
Means
B-A
Diff
12
P
2
LSR
8.95
D
                               2
                              65
                   Decision:
                                    There  is  a significant difference
                                    between  the two mean rates of
                                    suspended solids removal.
                               D-46

-------
                    BOD Removal  Using Screen and

                         Flotation Tank
X
47
26
9
82
X-X
20
1
-18

(X-X)2
400
1
324
725
27.3
                                                V362.5
                                                         19.04
 Y  =  27
                                                      75
                Total Solids Removal Using Screen and

                           Flotation Tank
      X-X
           (X-X)2
35     8
30     3
15    12
  80
26.7
    =  27
                64
                 9
               144
             217
                                              75
    95% confidence interval obtained from Table V,  Manual  of
    Experimental Statistics.
                                  D-47

-------
                             TABLE  D-5
      One way analysis of variance for the suspended  solids removal rates  using

the various combinations of the screen cyclones and flotation cell.  No chemicals
in use.
Null Hypothesis
Ho:  There  is no  significant difference between the mean total suspended
solids removal  rates  for  the five modes of  operation shown in Table 2.

Alternate Hypothesis
Ha:  There  is a significant  difference between  the mean total suspended
solids removal  rate  for  the  five modes of  operation shown in Table  2.

<=*-   =  0.05
F^   =  3.16

Criteria:   Reject  HQ  if  F>  F   ; reserve  judgement if F ^ F,^

Result:  F  = 4.91

Decision:   F is greater  than Fo<  , therefore reject H ;
            there  is  a significant difference between these
            mean total suspended solids removal  rates.
                                D-48

-------
                  BOD  Removal  Using Screen,

               Primary Cyclone,  and Flotation Tank
X    X-X    (X-X)2
 57     22    484
 36      1       1
 36      1       1               S  = \/93I  =  ]]237 .8   =   15.25
 33    - 2       4                      4
 14    -21    441
176	931        35 - 15.3(2.776)  <  ju  ^   35  + 15.3(2.776)
35.2                             /5~                           /F


 X"  =   35                    35 - 19  ^  ,u  <  35 +  19

                                  16  ^  w  <  54
                               D-49

-------
                  BOD  Removal Using Screen,

          Two  Secondary  Cyclones and Flotation Tank
  X  X-X   (X-X)2
 75     34    1156                     	     	
 29    -12     144               S  = ^1784  -  i/892  =   29.9
 19    -22     484                      2
123	1784
 41

 *  -  41                       5  ^  ^  ^  80  *
      95% confidence interval obtained  from  Table  V,  Manual
      of Experimental Statistics.
                              D-50

-------
                   BOD  Removal Using Screen,

               Three Cyclones  and Flotation Tank
X
44
44
40
16
144
X-X
8
8
4
20

(X-X
64
64
16
400
544
36

X
36
                                S = x/544  = \Tl81. 3  = 13.5
                                      3

                        36  -  13.5(3 .182)  .£  ju  <  36 + 13.5(3 .182)
^  p.  <   57
               Total Solids Removal Using Screen,

          Three Secondary  Cyclones and Flotation Tank
X
41
'29
28
21
20
13
11
163
X-X
18
6
5
2
3
10
12

(X-X)2
324
36
25
4
9
100
144
642
23.3
                                S = \/642
                                      6
                                               10.3
   =  23
                  Z3 -  10.3(2.447)  ^  ju   <  23 + 10.3(2.447)
                         /T

                  23-9.5   ^  >u  ^  23+9.5

                        13   ^ ju   <  33
                              D-51

-------
                           ONE  WAY  ANALYSIS  OF VARIANCE

        BOD REDUCTION USING VARIOUS  COMBINATIONS OF SEPARATORY EQUIPMENT
All Equipment
Screen & Flotation Cell
Screen ,
Screen ,
Screen ,
Flotation
Flotation
Flotation
Cell,
Cell,
Cell,
Primary Cyclone
2
3
S econdary
Secondary
Cyclones
Cyclones
130
82
176
70
144
16900
6724
30976
4900
20736
3556
2966
7126
1636
5728
5
3
5
3
4
3380
2241
6195
1633
5184
26
27
35
23
36
TOTALS
                                             602
21012  20  18633
                                                                                 k - 5
                                                                                 k-1 - 4
                                                                                 N = 20
                                                                                 N-k - 15
                                                                                 o<  = 0.05
                                                                                 F_^  - 3.06
    602
C » T
N
SSB =
SST
SSE
MSB

MSB
F -

1 = 362404 • 18120
20
T±2 - C - 18633 - 18120 - 513
n
= 2£Xi2 - C - 21012 - 18120 = 2892
= SST - SSB - 2379
- 513 - 128.25
4
- 2379 - 158.6
15
MSB - 128.25 - ' 0.807
MSB 158.6

Source of
Variation
Between
Samples
Error

Total



Degrees of Sum of Mean
Freedom Squares Square
4 513 128.25
15 2379 158.6

19 2892


                                         D-52

-------
                               TABLE D-6




        One way analysis of variance for the BOD reduction rates using the various





 combinations of the screen,  cyclones and flotation cell.  No chemicals were used.







 Null  Hypothesis




 HQ : There is no significant difference between the rates  of BOD




 reduction for  the  operational modes  listed in Table 2






 Alternate Hypothesis




 Ha ; There is a significant difference between the rates of BOD




 reduction for  the  operational modes  listed in Table 2.






 «=»«     = 0.05




 F^     = 3.06
 Criteria:  Reject HQ  if  F > F    ;  reserve judgement  if  F-^
 Result:   F  =  0.807
Decision:  F  is  less than
                                 ; reserve judgement.
     This one-way analysis  of  variance indicates  that any difference




between the  rates of BOD reduction in Table    is  due to chance  and




that changes  in auxiliary equipment do not significantly affect




BOD reduction  rates.  Apparently  flotation produces the major  reduction




in BOD.
                                  D-53

-------
               Total Solids Removal Using Screen,

             Primary Cyclone and  Flotation Tank
X
27
23
13
3
66
X-X
10.5
6.5
3.5
13.5

(X-X)2
110.25
42.25
12.25
182.25
347 .00
V/116
                                                       10.8
                                 0%
 65%  *
      16
*  95% confidence interval  obtained from Table V, Manual  of
   Experimental Statistics.
                              D-54

-------
70
                Total Solids  Removal Using

         Two  Secondary Cyclones  and Flotation Cell
X    X-X     (X-X)
24      1      1
24      11               S = \I~T~  =  1.225
22      1      1                   V  2
23                       23 -  (1.225) (4.303)  ^  ;u  ^.   23  +  (1.225) (4.303)
                                   3                                  3

                         23-3  
-------
             Total Solids Removal Using  Screen,


        Three Secondary Cyclones, Flotation  Tank  With


                  Alum and Tretolite FR-50
        X-X  (X-X)2
 61     0.5    .25               S  = \ /0.5 0 = 0.707
 60    -0.5    .25                    V~T
 121	0.50
 60.5

 _                              15%  £ M  <  100%  *
 X  =  60                                  ~
*
   95%  confidence  interval  obtained from Table V, Manual of
   Experimental  Statistics.
                             D-56

-------
                                  ONE WAY ANALYSIS OF VARIANCE

               TOTAL SOLIDS REMOVAL USING VARIOUS COMBINATIONS OF SEPARATORY EQUIPMENT

All Equipment
Screen Flotation Tank
Screen, Primary Cyclone , Flo ta t ion Tank
Screen, 3 Secondary Cyclone, Flotation Tank
Screen 2 Secondary Cyclone , Flo tation Tank
Totals
TI
134
80
66
121
70
471
'I2
17956
6400
4356
14641
4900

^
X
3390
2350
1436
7321
1636
1 £1 T 1
n
7
3
4
2
3
1 Q
T^/n
2565
2133
1089
7320
1633
i /. 7 /. n
X
19
2 7
16
60
23


k
k-1
N
N-k

F

« 5
« 4
= 19
- 14
= 0.05
= 3.11
      471


        I!
        N
SSB  =
SST
slii
   n
=  471'
    19
                 - C
                 - C
SSE
MSB
MSE
SST -
= SSB
k -1
= SSE
N-k
SSB
3064
4
1393
14
221841
  19
           14740
     11676
11676
  3064
           16133   -  11676    =  4457
                       =  4457 - 3064
                           766
                           9.95
                           1393
                           Source  of    Degrees     Sum  of   Mean
                           Variation   of  Freedom   Square   Square
                           Between
                           samples

                           Error

                           Total
                                                          4

                                                         14

                                                         18
                                      3064

                                      1393

                                      4457
                                                                                  766

                                                                                  9.95
F  =  MSB
      MSE
   776   =   78
  9.95
                                           P-57

-------
                            TABLE D-7






       One way analysis of variance for removal of total solids using the




various combinations of the screen,  cyclones and flotation cell.  No chemicals




were used.






Null  Hypothesis




HQ:   There  is no significant difference  between  the mean removal rates




of  total  solids for the  operational  modes listed  in Table 2.






Alternate Hypothesis




Ha:   There  is a significant  difference  between  the  mean removal  rates




of  total  solids for the  operational  modes listed  in Table 2.






   Foe   ; reserve judgement if F-£ F^  .






Result:   F  =   78







Decision:   Cannot reject HQ; there is  a  significant difference




between the rates of total  solids removal.  The difference exists between




the  otal  olids removal rate for the screen, 3 secondary cyclones, and




flotation  cell and the other treatments.
                                D-58

-------
       Total Phosphate  Removal  Using the Various

Combinations of The  Screen,  Cyclones and Flotation Cell
X
37
36
33
21
21
20
17
13
10
8
8
7
6
5
4
2
2
2
252
X-X
23
22
19
7
7
6
3
-1
-4
-6
-6
-7
-8
-9
-10
-12
-12
-12

(X-X)2
529
484
361
49
49
36
9
1
16
36
36
49
64
81
100
144
144
144
2332
14
    14
                      14  -  2.11(11.7)   ^  »  .<.  14 + 2.11(11.7)
                            VT8~

                      14-5.8   ^  M  ^  14+5.8

                         8   <  yu  <  20
                             D-59

-------
           Total Nitrogen Removal  Using  the Various

    Combinations of The  Screen,  Cyclones  and Flotation Cell
X X-X
(x-x)2
*32
*21
10
8
8
8
6
6
5
5
5
4
1
0
0
0
0
66
5.6
3.6
3.6
3.6
1.6
1.6
0.6
0.6
0.6
0.4
3.4
4.4
4.4
4.4
4.4

31.36
12.96
12.96
12.96
2.56
2.56
.36
.36
.36
.16
11.56
19.36
19.36
19.36
19.36
144.24
                               S   = y/144.24   \/10.3  =  3.21
                                       14

                      4.4  -  (2.145) (3.21)   *  p.  <  4.4 + (2 . 145) (3 . 2 1)
                                                                  ~
                       4.4-1.8   ^  »  ^  4.4+1.8

                          2.6   <   11  ^  6.2
4.4                        *  Values disregarded in computation
                             o £  mean.
                               D-60

-------
Computations of the mean removal rates of suspended solids, BOD,
total solids, total phosphate and total nitrogen using various
chemical treatments.  All mechanical separation equipment on
stream.
Waste Flow Rate    =  350 GPM

 £P                =   50 psi

Air Feed Rate      =   30 cfm
95% confidence interval was calculated using values in Table  II
    as found in the Manual of Experimental Statistics. (  )
                                   Where
       N-l                         X  =  Removal rates
                                   X  =  Mean removal rate
                                   N  -  Number of observations
                                   ji  =  Mean population removal rate
X  -  t S
       /TT
                              D-61

-------
         Removal of Suspended Solids Using No Chemical Treatment
X
68
63
61
61
61
60
58
34
27
493
55
X
68
63
61
61
61
60
58
34
466
58
X
68
63
61
61
61
60
58
432
x-x
13
8
6
6
6
5
3
-21
-28
Totals

X-X
10
5
3
3
3
2
0
-24
Totals

X-X
6
1
-1
-1
-1
2
-4

(X-X)2
169
64
36
36
36
25
9
441
784
1600

(X-X)2
100
25
9
9
9
4
0
576
732

(X-X) 2
36
1
1
1
1
4
16
60
62
                                 S   =  \/1600  =  \/200   =   14.14
                                 If  Q  >  1.91,  Reject  27 **

                                 =  28    1.98   Reject  27
                                  14.14
                                 S = 1/732  =   27.055  =  10.22
                                     * 7       2.646

                                 If Q  ^  1.860, Reject 34**
                                   =   24 .
                                       10.22
           =  2.348,  Reject 34
62 - 3.162(2.447)   ^  p
        \rr

  62-2.9   <  /a  ^  f. 2

    59.1   ^  M  ^  64.9
                                                              62-3.162 ( 2 . 4|
                                                           -*• ? . 9
** Application of Chauvenet's Criteria;  critical values  found  in
   Table A-6, Basic Statistical Methods.
                              D-62

-------
                      Removal of Suspended Solids Using Alum
           X-X
          (X-X)2
              S =1/2050  =/683 = 26.1

92
69
68
29

258
64
X =

28
5
4
35



64

784
25
16
1225

2050


3

Reject 29

Q = 35
26.1

Cannot re1
64 - 26.1 (3.


if Q > 1.53 **

- 1.34


ect 29
182) . „ . <
                                     2                             2
                   64 - 41.5
                                            ju
                                                  64 +  41.5
                          22
                                                  100
                       BOD Removal Using  Alum
   27
  237
  47.4
          X-X
   73      26
   59      12
   50        3
   28     -19
-20
     =   47
          (X-X)2
676
144
  9
361
400
        1590
                          S = 1/1590   = /398
                              ' 4
                         19.95
47 - 19.95(2. 776)   -£  p.  <  47 +  19.95(2. 775)
            /T
              47-24.8

                     22
                                         <  47 + 24.8

                                         .   71
**  Application of Chauvenet's  Criteria;  critical  values found in
   Table A-6, Basic Statistical Methods.
                                D-63

-------
  Removal of Suspended Solids Using Alum and Tretolite FR-50
   X-X
(X-X)
100.0
88.4
78.8
77.5
73.0
71.0
58.2
*55.4
54.1
51.3
*42.4
39.6
*12.4
691.9
30.8
19.2
9.6
8.3
3.8
1.8
-11.0
--
-15.1
-17.9

-29.6


948.6
368.6
92.2
69.2
14.4
3.2
121.0

228.0
320.4

876.2

3041.8
69.2
                               Eliminated  because of  blood
                               present  or  low pH  (3.2).




Eliminate 39.6%
X
88.4
78.8
77.5
73.0
71.0
58.2
54.1
51.3
552.3
69.0
X-X
19.4
9.8
8.5
4.0
2.0
-10.8
14.9
17.7




and 100
(x-x)2
376.4
96.0
72.2
16.0
4.0
116.6
222.0
313.3
1216.5

S=\/3042 = ^304 = 17.4
10
% as outliers.

S = 1/1216.5 = V173.8 = 13.2
V 8

69.0 - 13.2(2.365) ^ p < 69.0 + 13.2(2.3651
1 8 . /~8~


69.0 - 11.0 *z p ^ 69.0 + 11.0

58.0 ^ u , 80.0
69
                        D-64

-------
        Removal of Suspended Solids Using Alum and Dow 1188. 1A
     Chemical  feed  rate adjusted to give least  turbidity.
=  93
         X-X     (X-X)2
97
96
92
92
87
466
93
.2
.5
.9
.3
.6
.5
.3
3
3
0
1
5


.9
.2
.4
.0
.7


15
10
1
32
59

.21
.24
.16
.00
.49
.10

s =\/59.lO
4
93.3 - 3.84(2. 776)
/5~

93.3-4.8 /
                                 88.5  <
 /14.77   =   3.84






 u  ^  93.3 + 3.84(2.776)







:  93.3  + 4.8




<   98.1
                           D-65

-------
          Removal of Suspended Solids Using Alum and

                   Dow SA1188.1A
  Chemical feed rate varied by pattern

  4  mg/1  SA 1188.1A + 75 mg/1 and 100 mg/1 alum

  8  mg/1  SA 1188.1A + 75 mg/1 and . 100 mg/1 alum
X
*77
71
65
63
61
339
67

.4
.6
.1
.6
.8
.5
.9
X-X
9
3
-2
-4
6

.5
.7
.8
.3
.1
Totals
(X-X)
90
13
7
18
37
167
2
.25
.69
.84
.49
.21
.48
                                 =\A67.48  = \/41.87  =  6.47
                                  V   /l      I
                   67.9 - 6.47(2.776)  *   P  ±  67.9  + 6 . 4 7 (2^7^
       68                    ^"

                     67.9-8.0  ^  p  ^   67.9+8.0

                           59.9  <  u  <   759
*  Heavy blood load in the influent  stream.
  One experiment was performed  in  which  all  flow (350 GPM)
  was forced through one cell of  the  flotation tank.   This
  in effect halved the retention  time  in the flotation tank.
  75 mg/1 alum and 50 mg/1 Dow  SA1188.1A were used as
  flocculation aids.

  Input was 207 mg/1 T.S.S.; output T.S.S.  was 30 mg/1 for
  a removal rate of 85.5%.  The test  was of  4 hours duration,
                        D-66

-------
                    Removal of Suspended Solids
 Using FeCl3 only
                                        S = \/0 .50  =  0. 707
                                              1
       x-r
 90. 7   0.5     0.25
 89 .8  -0.5     0.25
180.5
 90.2
       90
0.50
              90.2 - (.71) (12.7)
<£,  90.2 +  (.71)(12.7)
              \T~2
                              90.2   £  6.4  ^  AI  ±  90.2 + 6.4

                              83.8   <  AI  <  96.6
 Using  FeCl3  + Alum + Tretolite  FR-50
X
92. 1
97.4
96.6


X =


X-X (X-X)2
3.3 10.89
2.0 4.00
1.2 1.44


95




S = J16.33
V 3 '
95.4 - 2.33(4.3) <
3

95.4-^.8 ^ Ai ±
89.2 ^ Ai ± 100


= \/ 5.44

1^ ^*


95.4 +

                                                             =   2.33


                                                            95.4  + 2.33(4.3)
                                                                      3
                                   D-67

-------
         ONE WAY ANALYSIS OF VARIANCE




SUSPENDED SOLIDS REMOVAL DURING NON-RAIN EVENTS
Ti Ti2
No Rain
No Chemicals 432 186624
Alum 258 66564
Alum + Tretolite 552 304704
Alum + Dow SA1188.1A 467 218089

Totals 1709
T = 1709
C = T2 = 2920681 = 116827
N 25
SSB » T.2 - C

n
SSB = 120776 - 116827 = 3949

SST ^^^X-L2 - C

SST = 128212 - 116827 = 11385
SSE - SST - SSB = 11385 - 3949 -
MSB = SSB = 3949 - 1316
k-1 3
MSE - 7436 - 354
21
F - MSB = 3.72
MSE
29
XM rri *• y "v"
^ n 1 £ /n X
26720 7 26661 62 k = 4
18690 4 16641 64 k - 1 - 3
39320 9 33856 69 N = 25
43482 5 43618 93 N - k = 21
<=>< = 0 .05
128212 25 120776 F = 3i07




Source of Degrees of Sum of Mean
Variation Freedom Squares Square
Between
Samples 3 3949 1316

Error 21 7436 354

7436 Total 24 11385






                   D-68

-------
                   DUNCAN'S MULTIPLE RANGE TEST

                         (MODIFIED VERSION)

Suspended solids removal using various combinations of chemicals
Non-Rain Events

     No Chemicals
     Alum

1.  Alum + Tretolite FR-50
2.  Alum + Dow SA1188.1A
                              X
                             69
                             93
S-  =
    = \/(MSE)2  -y/(354)2
      Vn + r,    V   14
      0.5;  N2
                   21
50.6
7.11
                                   rj. &
                                            -   Sample sizes
1 2
Ranked Means 69 93
Means
2-1
Diff
21
P
2
LSR
20.9
                                   Decision:  There  is a  significant
                                      difference between  the  rates  of
                                      suspended solids removal  for  alum
                                      and Dow SA1188.1A.   Inspection
                                      shows that the difference  between
                                      the suspended  solids  removal  Bate
                                      for alum and Dow SA1188.1A and the
                                      other treatments would  also be
                                      significant.
                                D-69

-------
                              TABLE  D-8







       One  way  analysis  of variance  for suspended solids removal rate




as indicated below.  The  chemical treatments  to  be  analyzed  include:




(1)  No chemicals;  (2)  Alum  only;  (3)  Alum plus Tretolite FR-50;




and (4) Alum plus Dow SA1188.1A.






Null Hypothesis




HQ:  There  is  no significant  difference between  the total suspended




solids removal rates for  the  chemical  operations listed above.






Alternate Hypothesis




Ha:  There  is  a significant difference  between  the  total suspended




solids removal rates listed for  the  chemical  operations listed  above,






ex    = 0.05






F^   - 3.07






Criteria:   Reject HQ if F > F   ; reserve  judgement if F  ^  F.<






Result:  F  =  3.71






Decision:   F is greater than  F«<  ,  therefore  reject H0.  There  is




a  significant  difference  between  these  mean total suspended  solids




removal rates.




     The application of the modified version  of  Duncan's Multiple




Range Test  indicates that  a   difference exists  between the  chemical




treatment using alum plus  Dow SA1188.1A and the  other chemical  treat-




ments .
                              D-70

-------
                           Total Solids Removal

                     Using No Chemical Treatment
       X-X    (X-X)2
  40    21      441
  26      7       49
  24      5       25                    	     	
  17-2        4             S   =  1/825  = 1/13775  =  11.8
  10   -  9       81                      6
  10-9       81
   7   -12      144       19.1 - 11.8(2.365)  ^  ju  ^  19.1 +  11.8(2.365)
 134	825                 
-------
  43
  41
  31
  19
335
         X-X
  9
  7
 -3
-15
       34
                     Total Solids Removal Using Alum
          (X-X)
 81
 49
  9
225
                  364
S =./364  =  1/121.3   =  11
                   33.5 - (11)(3.182)
                               2

                   33.5 - 17.5  ^  /i

                            16  ^  ^
                                                          11(3.182) +  33.5
                                                            2
                                                   33.5 + 17.5

                                                   51
                               D-72

-------
Total Solids Removal Using Alum and Tretolite FR-50
X
34
31
29
26
13
13
4
2
2
154
(X-X)
17
14
12
9
-4
-4
-13
-15
-15

(X-T)2
289
196
144
81
16
16
169
225
225
1361
17-1
                                            70.1  =   13.0
17.1 -
                          17.1  -
  17
13(2.306)
   3

9.9  A  »

7.2     #1
                                                     17.1 + 13(2.306)
                                                                3
                     17.1+9.9

                     27
                          D-73

-------
                        ONE  WAY  ANALYSIS OF VARIANCE
               Total Solids Removal Using Various Chemical Treatments
                                          n
No Chemicals
Alum
Alum + Tretolite FR-50
Alum + Dow SA1188.1A

Totals
134
134
171
185

624
17956
17956
29241
34225


3390
4862
3996
6707

18955
7
4
9
6

26
2565
4489
3249
5704

16007
19
34
17
31


k
k
N
N
ex
F
- 4
-1 = 3
- 26
- k - 22
c; = 0.05
= 3.05
624
C  =  T_  =  (624)   -  389376   -   14976
      N       26        26

SSB= v-T±2  - C  -  16007 -  14976   =  1031
SST=^
SSE =
MSB =
MSE =
F -
ElXi^
SST
SSB
k-1
SSE
N-k
MSB -
MSE
- C =
- SSE =
- 1031
3
= 2948
22
344 -
134
              18955 -  14976

                3979 -  1031

                -  344


                =  134


                2.57
3979

2948
Source of
Variation

Be tween
Samples

Error
          Total
                                                        Degrees  of
                                                        Freedom
                                                                   3

                                                                  22


                                                                  25
                                      Sum of    Mean
                                      Squares   Square
1031

2948


3979
344

134
                                      D-74

-------
                                TABLE  D-9



       One way analysis of variance of removal of total solids with the various



chemical treatments listed below.   The chemical treatments to be analyzed



include:  (1) no chemicals; (2) alum only; (3) alum plus Tretolite FR-50; (4)



alum plus Dow SA1188. 1A.



Null Hypothesis



H  :  There  is no significant difference between the rates of removal of total



solids  using the various chemical  treatments listed above.




Alternate Hypothesis



H  :  There  is a significant difference between the rates of removal of total
 cl


solids  using the various chemical  treatments listed above.
       = 0. 05



     oc = 3. 05



Criteria:  Reject  H  if F - F^   ; reserve judgment if F <.  Foe  .



Result:   F = 2. 57



Decision:  F is less than Foe , therefore, reserve judgment.   There is no



significant difference in the total solids removal rates using  the chemical



treatments listed  above.
                                  D-75

-------
             BOD Removal Using  No  Chemical Treatment
X
59
36
27
27
21
19
189
X-X
27
4
-5
-5
-11
-13

(X-X)2
729
16
25
25
121
169
1085
31.5
                                            =  1/2l7


                                 S  =  14.7

                                 If Q  >.  1.73, Reject  59**

                                 Q     27  =   183,   Reject  59
                                     14.7
X
36
27
27
21
19
130
X-X
10
I
1
-5
-7

(X-X)2
100
1
1
25
49
176
26
                                 S  = ^176  -  1/44"  -   6.633
                                        4
      26
26 - 6.63(2.776)   <;   u  <_  26 + 6.63(2.776)
        i/T                         7?

26 - 8.2  <  /i  ^  26 + 8.2

18  ^  p  <  34
**  Application of Chauvenet
Table A-6, Basic  Statistical
  's Criteria;
   Methods.
critical values found  in
                              D-76

-------
           BOD Removal Using Alum  and  Tretolite FR-50
        X-X
(X-30
89
77
71
70
58
56
53
51
36
31
28
18
638
36
24
18
17
5
3
0
-2
-17
-22
-25
-35

1296
576
324
289
25
9
0
4
289
484
625
1225
5146
53.2
                                            =  V4 6 7 . 8  =  21.6






                              53 - 21.6(2.201)  ^  ju  <  53 +  21.6(2.201)
                              53-13.7  ^  »  ^  53 + 13. 7




                                  39.3  ^  u  ^  65.7
X  =  53
                              D-77

-------
                      BOD  Removal Using




                   Alum and  Dow  SA1188.1A
X
76
74
71
49
46
316
63.2
X-X
13
11
8
-14
-17

63.2
(X-X) 2
169
121
64
196
289
837

S = 1/837 = 1/209
V 4 '
63 - 14.5(2.776) ^ p
/5~
14.46

-------
                            BOD Removal
 Using Fed-  Only
X
22
62
84
X-X
+20
-20

(X-XK
400
400
800
42
       42
                                    S = /800  =  28.28
                                     <  ju  <  80 *
 Using FeCl3 + Alum +  Tretolite  FR-50

   X   X-X
  88
  83
 171
85.5
-2.5
(X-X)2
  6.25
  6.25
       12.50
S = yi2.50
        1
                                          3.54
       86
                               86  - 3.54(12. 7)  <  p  <    86  + 3.54(12. 7)
                                      rr                           VT
                      85.5  -  32   <.  p

                      54  <  /i      100
                                                   85.5 +  32
 *  95% confidence  interval  obtained from Table V, Manual of
    Experimental  Statistics.
                                D-79

-------
          ONE WAY ANALYSIS OF VARIANCE

BOD REDUCTION USING VARIOUS  CHEMICAL  COMBINATIONS
T. Tt2 X.2
No Chemicals 130 16900 3556
Alum 237 15169 12823
Alum + Tretolite 638 407044 39066
Alum + Dow SA1188.1A 316 99856 20810
TOTALS 1321 76255
T = 1321
C = T2 = 1745041 - 64631
N 27
SSB= yTt2 - C = 68505 - 64631 = 1874
n
SST = £Zxi2 - C - 76255 - 64631 = 11624
SSE= SST - SSB - 9750
MSB= SSB - 1874 » 625
k-1 3
MSE= SSE - 9750 • 424
N-k 23
F = MSB - 625 = 1.74
MSB 424
n Ti2/n Y
5 3380 26 k
5 11234 47 k
12 33920 53 N
5 19971 63 N
27 68505 F
Source of Degrees of
Variation Freedom
Between
Samples 3
Error 23
Total 26
                                                        -  4
                                                        •1  =  3
                                                        =  27
                                                        • k  =  23
                                                         = 0.05
                                                         = 3.03
                                                           Sum of    Mean
                                                           Squares   Square
                                                              1874

                                                              9750


                                                              11624
624
                            D-80

-------
                      TABLE  D-10





   One way analysis of variances  of  BOD  reduction using all



separatory equipment with various  chemical  treatments as



indicated below.  The chemical  include:   (1)  no chemicals,



(2) alum only,  (3) alum plus  Tretolite  FR-50, and (4)



alum plus Dow SA1188.1A.



Null Hypothesis



HQ:  There is no significant  difference  between the rates of



BOD reduction for the chemical  treatments listed above.







Alternate Hypothesis



H  :  There is a significant  difference  between the rates of
 a


BOD reduction for the chemical  treatments listed above.







ex:        =  0.05



Foe       =  3.03



Criteria:  Reject H  if F>  F   ;  reserve judgement if F ^  F



Result:  F  =   1.47



Decision:  F is less than Fix.  ,  therefore the null hypothesis



cannot be rejected.



   The one-way  analysis of variance  indicates that there is



apparently no significant difference between the rates of



BOD reduction for the chemical  treatments listed above.
                            D-81

-------
                   Total  Phosphate Removal

                  Using No  Chemical Treatment
 X   X-X    (X-X)2
 67     38    1444
 52     23     529
 21   - 8      64               S  = 1/3088  = \J617 .6  =  24.84
 20   - 9      81                    V 5
  8   -21     441
  6   -23     529      29  -  2.571(24.84)  -c  ju  ^  29 +  (2.571) (24.84)
174	3088             2.236                          2.236
 29
                      29-28.6  -i  M  <:  29+28.6
X~ = 29
                       0  -:  u  -c  58
                     Total  Nitrogen Removal

                  Using  No  Chemical Treatment
      X-X   (X-X)2
 16    3.4  11.56              S   = 1/23.20  = /5T8   =  2.408
 14    1.4   1.96                     4
 12   -  .6     .36
 11   -1.6   2.56
 10   -2.6   6.76        12.6- 2.41(2.776) ^ ju <. 12.6 + 2.41(2.776)
 63	23.20
 12.6                    12.6  - 3.0  ^  »  ^  12.6  +  3.0

  = 13                      9.6^^<.15.6
                             D-82

-------
             Total Phosphate  Removal Using Alum
X
78
69
48
39
31
265
53
X
X-X
25
14
-5
-14
-22

= 53
(x-x)2
625
196
25
196
484 53
1526


S = 1/1526 = \/381.5 = 19.53
' 4
- (19.53) (2.776) * » ^ 53 + (19 . 5 3) (2 . 7 76)
2.236 2.23o
53-24.2 ^ jj ^ 53+24.2
29 ^ M ^- 77
              Total  Nitrogen Removal Using Alum
X
21
17
7
4
4
4
19
4. 75
X-X


2.25
. 75
. 75
. 75


(X-X)2


5.0625
.5625
.5625
. 5625
6. 75

= 5
                             S =i/6.75  =  1/2.25
4.75 - (1.5)(3.182)
           2

4.75 - 2.75  ^  ^u  .

        2.0  ^  u  .
        1.5
                                                     4.75  + (1.5) (3. 182)
                                                                 2
4.75 + 2. 75

7.5
                            D-83

-------
Total Phosphate Removal Using Alum and Tretolite FR-50
X
75
64
60
42
38
37
31
25
14

386
42.9
X

X
X-X
32
21
17
-1
-5
-6
-12
-18
-31



- 43
Total
X-X
(X-X)2

1024 S = 1/3245 = 1/405.6 = 20.14
441 ' 8
289
1 43 - (20.14) (2.306) ^ u ^ 43 + (20 . 14) (2 . 306 )
25 3 3
36
144
324 43 - 15.5 ^ u < 43 + 15.5
961
77 , ?» - SQ
3245 +


Nitrogen Removal Using Alum and Tretolite FR-50
(X-X)2
30 Eliminated as Outliers
24
8
8
7
7
2
2
1
35
5
T =


3
3
2
2
-3
-3
-4


5


9
9
4 S = i/60 - \/10" = 3.162
4 V 6
9
9
10 5 - (3.16X2.447) , u j. 5 + (3.16X2.447
60 f7~ ^7-

5-2.9 ^ M ^ 5+2.9
2 ^ u ^ 8
                       D-84

-------
 Total  Phosphate Removal Using  Alum plus Dow SA1188.1A

  X    X-X   (X-X)2
  57    23    529
  44    10    100
  37     3      9
  21    13    169
  12    22    484
 171
34.2

X  =   34
      1291
                                 \/322.7  =  17.96
         34.2 - 17.96(2.776)
                  2.336
                            34.2  + (17.96) (2.776)
                                       2.336
                      34.2 - 22.3  *.  ju  *.   34.2  +  22.3

                              12            56
                Total Nitrogen Removal Using Alum plus Dow SA1188. 1A
   X
   17
   16
    0
    0
    0
    33
X-X  (X-X)2
 10
  9
  7
  7
  7
   6.6
  X  =  7
100
 81
 49
 49
 49
      328
S  =
        328
\/82
9.06
6.6 - (9.1)(2.776)
                             6.6 + (9.1)(2.776)
            6.6  -  11.3  ±  u

                     0  ^  11
                                        6.6  + 11.3

                                        17.9
                              D-85

-------
                      Total Phosphate Removal
Using FeCl3  Only
 73
 73

146
"75"

X  =
                                S   =  0

                              30 ^  ju  <  100 *
73
Using FeCl3 + Alum +  Tretolite  FR-50
X
90
71
161
X-X
9.5
9.5

(X-X)2
90.25
90.25
180.5
80.5
                                    V180.5
                                         13.4
                  80
                  35%
                                          100% *
Using FeCl3 Only
  9
  3
 12
X-X
  3
 -3
             (X-X)2
9
9
        18
                      Total  Nitrogen Removal
                 S  = 1/18  =   4.242
                                 0%   ^  AI  -c  50%
FeCl.
Using FeCl3 + Alum + Tretolite  FR-50




2.
X~
X
5
0
5
5
_
X
2
2


2
-X
.5
.5



(X-X)2
6.
6.
12.


25
25
5


                                   12.5   =  3.46
                                              45% *
* 95% confidence interval  obtained  from Table V,  Manual of
Experimental Statistics.

                               D-86

-------
           ONE WAY  ANALYSIS  OF VARIANCE




TOTAL PHOSPHATE REMOVAL  USING CHEMICAL TREATMENT

No Chemicals
Alum
Alum + Tretolite FR-
Alum + Dow SA1188.1A

Totals
C = T2 = 996 =
N 25
SSB =yT..2 - C
n
SST ^^Xi2 - C =
SSE = SST - SSB

MSB - SSB = 1813
k-1 3
MSE = SSE = 8090
N-k 21
F = MSB = 604 =
MSE 385
T± Ti2 Xi2 n
174 30276 8134 6
265 70225 15631 5
50 386 148996 18680 9
171 29241 7139 5

996 49584 25
992016 - 39681
25
= 41494 - 39681 = 1813

49584 - 39681 = 9903
9903 - 1813 = 8090

= 604

= 385

1.57

Ti2/n X
5046 29 k = 4
14045 53 k - 1 = 3
16555 43 N = 25
5848 34 N - k - 21
Cy; = 0.05
41494 F,^ = 3.07



Source of Degrees of Sum of
Variation Freedom Squares
Between
Samples 3 1813

Error 21 8090

Total 24







Mean
Square

604






                            D-87

-------
                       TABLE  D-ll




   One way analysis of variance of  removal  of  total phosphate




with the chemical  treatments  listed  below.   The chemical treat-




ments to be analyzed  include  (1)  no  chemicals;  (2)  alum only;




(3) alum plus Tretolite FR-50; and  (4)  alum plus Dow SA1188.1A.




HQ:  There  is no  significant difference between the phosphorous




removal  rates using  the various  chemical treatments listed above.
Alternate  Hypothesis




Ha:  There  is  a  significant  difference between the  phosphorous




removal  rates  using  the  various chemical treatments listed above.
 ex   =  0.05






 Fo<   -  3.07






 Criteria:  Reject  Ho  if  F >•  F«.  ,  reserve judgement if F  ^  F0






 Result:  F   =   1.57






 Decision:  F is  less  than Fo<  ,  therefore reserve judgement.




 There is no  significant  difference between the total phosphate




 removal  rates  with various  chemical treatments listed above.
                              D-88

-------
                        ONE  WAY ANALYSIS OF VARIANCE

             TOTAL NITROGEN REMOVAL USING CHEMICAL TREATMENTS

No Chemicals
Alum
Alum + Tretolite FR-50
Alum + Dow SA1188. 1A


Totals

Ti
64
19
35
33


151

V
4096
361
1225
1089




X 2
xi
818
97
235
545


1695

n
6
4
7
5


22

T±2/n
683
90
175
218


1166

X
11
5
5
7






k =
k-1
N =
- N-k
=><
F~


4
- 3
22
= 18
- 0.05
= 3.16
151
Il
N
SSB  =
  n
22801  =  1036
 22
=  1166 - 1036
SST
SSE
MSB
MSE
F =
= 52Xi2
= 529
• SSB
k-1
= SSE
N-k
MSB =
MSE
- C

= 130 =
3
• 529 =
18
43.3 =
29.4
1695 -

43.3
29.4
1.47
                                 130
                                 659
                                     Source  of
                                     Variation

                                     Between
                                     S amples

                                     Error
                                            Total
Degrees of
Freedom
    3

   18


   21
Sum of   Mean
Squares  Square
  130

  529


  659
                                                                                          43.3

                                                                                          29 .4
                                    D-89

-------
                      TABLE D-12
   One way analysis of variance of  the  removal  of  total
nitrogen with the various chemical  treatments  listed  below.
Chemical treatments to be analyzed  include:  (1)  no chemicals,
(2) alum only,  (3) alum plus  Tretolite  FR-50,  and  (4)  alum
plus Dow SA1188.1A.
Null Hypothesis
HO 5  There  is no  significant  difference between the mean nitrogen
removal  rates using the  chemical  treatments listed above.

Alternate Hypothesis
Ha:  There  is a significant  difference  between the mean nitrogen
removal  rates using the  chemical  treatments listed above.

•=x   =0.05

F«   =  3.16

Criteria:   Reject  HQ  if  F >• Foe ;  reserve judgement if F ^ Fo<   .

Result:  F  =   1.47

Decision:   F is less  than F«<  ,  therefore reserve judgement.   There
is no significant  difference  between the total nitrogen removal
rates using the various  chemical  treatments listed above.
                               D-90

-------
Computations of mean rates of  suspended  solids,  BOD,  total solids,

total phosphates, and total nitrogen  removal  using  all separatory

equipment, alum and Dow SA1188.1A.
      Waste Flow Rate  =  350  GPM

      A P              =   50psi

      Air Feed Rate    =   30  cfm -

      X = % Removal



      95 percent confidence interval  was  calculated using

         values found in the Manual of  Experimental Statistics

         (38).
                              Where
                              X   =   Removal  Rates
            N-l               ~X   =   Mean  Removal Rate
                              N   =   Number  of Observations
                              M   =   Mean  Population Removal Rate
      X - tS  ^ u  £_ tS_ + X
           N          N
                         D-91

-------
            Removal  of  Suspended Solids Using Screen,

       Three Secondary  Cyclones and Flotation Cell + Alum

                     and  Tretolite FR-50
 X   X-X
 90
 88
178
 89
  1
- 1
       89
      (X-X)2
  1
  1
       S =\     =  1.414
            1

89 - (1.414) (12.7)  £.  >u  <  89 + (1.414) (12.7)
        /T
                        89 - 12.7  ^  »  ^   89 +  12.7

                        75%  ^  u  <  100%



                 Removal of BOD Using Screen,

        Three Secondary Cyclones and Flotation Cell +  Alum

                       and Tretolite FR-50
 80
 57
137
     X-X
     (X-X)2
68.5
11.5
11.5
       68
132.25
132.25
      264.5
       S =/ 264.5
                         25
16.2
                                100 *
 *  95% confidence interval obtained  from  Table  V,  Manual  of
    Experimental Statistics.
                              D-92

-------
         APPENDIX  E




TYPICAL DATA OBTAINED DURING




   PLANT SHAKEDOWN  IN 1967

-------
      Data accumulated during  the  commissioning and equipment




shakedown exercises in late  1967  indicated  that the waste influent




contained a widely varying load  of industrial solids:  dissolved




and suspended.




      Graphs of some of  the  data  obtained  illustrate the hourly




and daily variations.  The relatively  low  suspended solids content




on November 18th and 19th clearly  suggests  a  weekend with little




industrial activity.  These  graphs are included on the following




pages .
                                   E-l

-------
                        VARIATION  OF TOTAL  SOLIDS

                        WITH TIME WEDNESDAY DEC. 13,1967
o
    24OOi-
5
o.
tO
(O

*
p
   20 OO-
    1600 -
    1200
     800
     4OO
            9:00
             AM
                        IOOO
I COO
12-00
NOON
                                                            100
                                                                        200
300
 PM
                                             TIME
                                              E-2

-------
                              VARIATION OF  SUSPENDED  SOLIDS WITH

                              TIME  WEDNESDAY DECEMBER  13,1967
    2500
    2000
(O
Q


O
at
UJ
0.
to

CO
     1500
     1000-
     500-
ro
 I
W
1
6:00
AM
1
900
1
IO-.00
1
IIOO
1
12:00
NOON
1
I:OO
1
^00
1
3:00
1
4-OO
PM
                                                    TIME

-------
                      VARIATION  OF SUSPENDED  SOLIDS
                      WITH  TIME  WEDNESDAY  DEC.  6 ,1967
    4000
9
E

tn
Q
CO
o
UJ
UJ
Q.
CO

CO
g
3000
2000
    1000
                    12.00
                    NOON
                           COO
2-00
3:00
                                                                PM
                                      E-4

-------
                         TOTAL SOLIDS mg/£ AS A FUNCTION OF TIME
                         WED. NOV.I5 THROUGH  SUNDAY  NOV. 19,1967
   6000
   5000
o<  4000
>v
9
E

o
CO
    3000
    2OOO
    1000
              J	L
     .1
     _L
                                                                  J_
                                                        _L
              12
 8    4
NOV. 15
                            12
8    4
 NOV. 16
                                          12
8   4
NOV. 17
                                                        12
8    4
NOV. 18
                                                                      12
8    4
NOV 19
                                   TIME AND DATE

-------
                                                                                        ACCESSION NO.I
                                                                                        KIT WOlDft
                                                           dual com-


                                                           1 <5)*the
                                                       Combined Sowar*

                                                       Storm Hater

                                                       Overflow!


                                                       Flotation.
                                                                                               Primary  Tr*atB«nt
                                                                                                •tori  tuaoff
                                                                                         ACCeSSIOR ».:
* fl.

The |
*y*tem for various • !** combined aewege
Of th« ayatem for automation and ua* la
overflows; (4) Tha edaotabll
remote location; and (S) Tb«
Combined Sawera

•tor* Vator

Ovorflova

Diaoolv*d-»Alt
Plotatloa
ayat**a appaaro po»albl* with conventional control cquipatnt.  Cha*ieal
aida to flocculatlon appear to b»a promlaa that warrant* further atady.
                                                        TroaCBant M*thod«

                                                        Primary TroatB*Rt

                                                        Ploccttlant Aid*



                                                        Storm lunoff
                                                                                          ACCESSION 10.i
 Tha  principal  aapacta  in»*«tls«ted waia:  (1) P«rfor»«nc« of  tha »7«e««
 durloc  rain evant*  and  dry  period*; (2)  Evaluation of individual com-
 ponent*;  (3) Capital  coata  and  operating coata for utlllting  a flotation
 •yatem  for  varloua  al*a combined  **w*ge  ovatflowa; (4) The adaptability
 of  Che  aystcm  for cutomatlon »nd  oac in  remote location; end  (5) The
 ability of  tha *yat*m  to treat  Intermittent and hlfhly variable flow*
                                                         Combined Sawcn

                                                         Storm Water

                                                         OvertIowa

                                                         Dlaaolved-Alr
                                                         Flotation

                                                         Infiltration
 dlaaolved-air  flotation ayatem* would be economical for handling com-
 bined eewer overflow* up to 8 HCD.   Automation of dl**olved-alr flotatioi
 ayatem* appaara poeaible with conventional control equipment.  Chemical
 aide to flocculatlon appear to have promlae that warranta further atudy.
 Toe *y*tam wa* unique in that all liquid floi
 air dloBolvlns tank with no recycle.  Domaat
 lieu of combined **wase during period* of no
                                               pa**ed din
                                                         Sueponded Solid*

                                                         Storm Knnoff

-------