Robert B. Williams
             Robert G. Gumerman
           William R. Whittenberg
                Nancy E. Heim
 Culp/Wesner/Culp - Clean Water Consultants
         El 'Dorado Hills, California
            Santa Ana, California
           Contract No. 68-01-5938
               Project Officer
                 Haig Farmer
       Municipal- Construction Division
      Office of Water Program Operation
United States Environmental Protection Agency
           Washington, D.C. 20460


     This report  has  been reviewed by  the  Municipal Construction Division,  U.S.
Environmental Protection  Agency,  and  approved for publication. Approval  does  not
signify that the  contents  necessarily reflect the views and policies of  the  U.S.
Environmental Protection  Agency, nor  does  mention  of  trade  names or  commercial
products constitute endorsement  or recommendation  for use.


     To order this publication,  "Recommendation  from Value  Engineering  Studies or
Wastewater Treatment Works"  (MCD-69)  from EPA, write to;

          General Services Administration (8FFS)
          Centralized Mailing List Services
          Building 41,  Denver Federal Center
          Denver, Colorado 80225
     Please  indicate  the  MCD  number and title of publication.

     Multiple  copies  may  be purchased from;

          National Technical  Information Service
          Springfield,  Virginia 22151


     This  publication summarizes  the  best  ideas/recommendations  from 93  value
engineering  (VE)  reports which  were completed under  EPA's mandatory  VE  program
for 75  construction grant projects.  Data  abstracted from  these  reports  provided
the basis  for  an  overall evaluation of the VE program. Application of VE ideas/
recommendations  and  evaluation  results  presented  in  this  publication  should
enhance  the  effectiveness  of VE  in the  design  of  future wastewater treatment

     Since the mandatory  value  engineering (VE) program was'  initiated  in October
1976, it  has  produced substantial construction cost savings  and  a high  rate  of
return for the VE investment. The  program has saved an average. of  5.1  percent  of
the construction costs on projects which  required VE studies. Stated another way,
the VE program has achieved a $12  return  for  each dollar  invested  in VE costs.

     This publication represents the  Environmental  Protection Agency's  (EPA) con-
tinuing efforts to evaluate and improve the effectiveness, of the VE program. The
publication  summarizes  the best ideas/recommendations  from  93  VE reports  com-
pleted under EPA's mandatory program  and  presents general information for improv-
ing the future performance of the  program.                                        .

     This publication does  not  present any regulatory  requirements. The require-
ments and guidance for conducting  VE  studies  on EPA funded projects are contained
in Section  35.926 of the Construction Grants Regulations, the Value Engineering
Workbook  (MCD-29) published  in  July 1976, and  the  Value  Engineering Case Studies
and Formats For Proposals and Reports published in June 1977.

     This publication  is  designed to  serve  as a reference source.for  wastewater
treatment  design engineers and VE study  teams in  their  efforts   to improve the
quality  of future  treatment facilities  while minimizing  the construction and
operational costs.

     The  Environmental  Protection Agency intends to  continually evaluate and
improve  the VE program.  Therefore, all users of this  publication  are  encouraged
to submit any pertinent  information on the VE  program to the Director, Municipal
Construction   Division   (WH-547),   Office  of   Water  Program  Operations,  U.S.
Environmental Protection  Agency, Washington,  D.C. 20460.
                                               Eckardt .C. Beck
                                               Assistant Administrator for
                                               Water and Waste Management  (WH-556)

                                TABLE OF CONTENTS
Chapter 1 - Introduction
     Purpose and Scope
     Description of VE Studies
     Criteria Used for Selection of VE Recommendations
     Recommendations on Conducting VE Studies
Chapter 2 - Basins and Tanks
     Design Concepts
Chapter 3 - Process Equipment
     Flow Equalization
     Pumps - Influent and Effluent
     Pumps - Process
     Flow Measurement
     Grit Removal
     Trickling Filters
     Aeration System  (Including Pure Oxygen)
     Post Aeration
     Chemical Feed
     Sludge Collection
     Sludge Thickening
     Sludge Dewatering
     Sludge Stabilization
     Sludge Disposal
Chapter  4 - Site Layout  (Plant  and Equipment)
     Equipment  and Process  Layout
     Hydraulics and Hydraulic Gradeline
Chapter  5 - Buildings  or Structures
     Size  ,
     Floor Plans
     Type of  Construction

                          TABLE OF CONTENTS  (Continued)
Chapter 6 - Electrical, HVAC and Controls
     Power Distribution
     Lighting.                                   •
Chapter 7 - Energy
     On-Site Generation                              ,
     Heat Recovery
     Conservation                                            ,
Chapter ,8 - Aesthetics
     Odor Control                             •
     Noise Control           •
Chapter 9 - Constructability
     Structural Details                     '''...:          ,    .
     Construction Sequencing                                .
Chapter  11 - Sewers      .,             -  .
     General Construction
Chapter  12 - Interceptor System Pumping Stations                . .  ...
     Emergency Generator
     Piping                                        ;      ;
     Design Concepts
Chapter  13 - Ocean Outfall
     Covering Material                                    :       •
     Construction Material                                      ,  .
     Construction Technique                                 ,  . •
     Design Concept                                            , .
Appendix A - Value Engineering Program Evaluation^             .
     Productivity of  VE Teams
     Potential VE  Savings        •                               ,
     Acceptance of VE Recommendations
     Identification  of  High Cost  Components
     Composition of VE  Teams
     Cost  and Level  of  Effort  for VE Studies
     Reasons  for  Rejection of VE Recommendations
     General Observations                                          .
Appendix B -  Ideas Applicable  to  Most Wastewater Treatment Projects
     Design  Criteria
     Site  Work  and Layout
     Site  Buildings
     Equipment                                                     ,
     Mechanical        ~                                .•'•...
- A-19

                          TABLE OF CONTENTS  (Continued)
Appendix B - Ideas Applicable to Most Wastewater Treatment Projects  (cont.)
     Electrical and ISC                                                     B-5
     Energy Conservation                                                    B-6
     Miscellaneous                                                          B-7

                                 LIST OF TABLES


                                  LIST OF FIGURES
  1    Change wye wall to tee wall.                                              8
  2    Reduce length of dividing walls.                                         10
  3    Square clarifiers instead of circular.                                   11
  4    Square clarifiers instead of rectangular.                                12
  5    Common wall construction between chlorination and post aeration.         17
  6    Simplify chlorine contact tank valving.                                  18
  7    Use  outboard launders.                                                   19
  8    Substitute earthern basin for concrete basin.                            25
  9    Revise inlet to pumping station.                                         28
 10    Right  angle drive system.                                                29
 11    Vertical turbine pumps.                                    <              34
 12    Combine pumping stations.                                                36
 13    Pump primary effluent directly to bio-filters.                           37
 14    Use  mixed flow pumps in lieu of screw pumps.                             39
 15    Use  vertical mixed flow pumps.                                           40
 16    Use  vertical mixed flow pumps instead of screw pumps.                    41
 17    Exchange grit channels for Pista grit chambers.                          46
 18    Simplify grit removal.                                                   48
 19    Replace primary effluent channel with pipe.                              50
 20    Replace low pressure air scum control system with
       collection mechanism.                                                  51
 21    Emergency drive for pure oxygen air compressor system.                   54
 22    Use  dual drives for blowers.                                             56
 23    Replace swing drop pipes with lift out drop pipes.                       58
 24    Use  complete mix activated sludge.                                       61
 25    Replace mixed liquor channel with pipe.                                  63
 26    Replace control valves with telescoping valves.                          76
 27    Use  precast concrete walls.                                              80
 28    Design sludge drying beds for mechanical equipment.                      81
 29    Mechanical  mixing in anaerobic digesters.                                83
 30    Replace retaining wall with precast panels  in H-piles.                   91
 31    Simplify return activated sludge flow balancing scheme.                  95
 32    Reduce length of yard piping.                                            98
 33    Delete drain pipes and gates from head end  of aeration basin.          100
 34    Relocate flow splitter box.                                            101
 35    Simplify mixed liquor piping.                                          102
 36    Use  single  mixed liquor pipe to secondary clarifiers.                  105
 37    Simplify scum handling system.                                          106
 38    Scrubber water recycle streams.                                         108
 39    Modular design of unit processes.            '                           110
 40    Relocate odor scrubber outside  building.                                112
 41    Raise  influent screw pumps.                                            115
42    Eliminate sludge conveyors.                                             120
43    Simplify gravity sludge thickening system.                              122
44    Use  reinforced concrete pipe for tunnels.                              129
45    Use  insulated steel  siding for  buildings.                              131
46    Substitute  acoustic  metal  panel  for "Sound  Blox".                       132
47    Use  fiberglass  covers  over tertiary filters.                            133

                           LIST OF FIGURES  (continued)
48   Dissolved oxygen control system.
49   Reduce size of main  control  room.
50   Install heat exchangers on effluent  sludge  line.
51 	Extended pump discharge pipe below water surface.
52   Use two-stage carbon for odor control.
53   Wall strut system.
54   Use steel framing.
55   Use "Shotcrete" fixed  cover  on anaerobic digester.
56   Use force main instead of  gravity  interceptor.


                                    CHAPTER 1
     Value Engineering  (VE)  was first introduced  into  the  EPA Construction Grant
Program on  a voluntary basis  in  1974 based on  the  success of  this  cost control
technique in other  Federal  agencies.  VE was described  as  a "systematic and crea-
tive  approach to  identify  unnecessarily high  costs  in  a project  in  order to
arrive at a  cost savings without  sacrificing the reliability or efficiency of the
project or increasing operating and, maintenance costs." The success of the volun-
tary program was measured in terms  of the following:

     ซ    Effective in  cbjst  control
     ซป    Substantial cost  savings  achieved              ,      .  . •.-
     9    Project  delays  can be avoided
     0    Quality  and reliability maintained
     9    Provides for  more  efficient and better design techniques.

     This success  prompted  the EPA to  institute the mandatory VE program in  1976
which  required all projects with a  total estimated^construction cost  (excluding
the  cost -of  sewers) of  $10  million or :greater to have  value engineering. Projects
with lower  estimated construction  costs  still are  encouraged  to participate  in
the  VE program on  a voluntary basis.                   ,  -            .   :

      The  summary results of the  voluntary program  and the mandatory program for
fiscal  years  1977,  1978  and 1979 are, Table  1.   This table  clearly,
shows  that  the mandatory VE program  has been successful when  measured  in terms  of
the  net savings.  The program has  realized  an average  savings  of  5  percent  in
project  costs and a net capital savings to VE  costs  ratio  of  more than 12  to 1.
                            RESULTS OF VALUE ENGINEERING PROGRAM


• •--'-
No .of VE
project costs

VE costs^

4.0 •

cost ratio
 1Includes VE fee and  implementation  costs
 2Voluntary program



     The purpose of this publication is to present  a reference  document of the
most* worthwhile ideas or recommendations from 93  Value  Engineering reports pre-
pared  for 75  projects  under EPA's  mandatory VE program.  This  publication  is
intended for use by design  engineers and future  VE  teams as  a "memory  jogger,"
either for specific  ideas or to  stimulate alternative suggestions and ideas.

     A secondary benefit of examinating  such  a large spectrum of  VE studies was
the  opportunity to conduct a general  evaluation  of the VE  program. This evalua-
tion should  provide  an excellent basis for  improving the effectiveness of future
VE studies.  The details of  the  evaluation are presented in Appendix A.


     All of  the  VE  studies  were  conducted  on "mechanical"  wastewater treatment
facilities,  pumping systems, sewers,  outfall  systems.  A VE  analysis  of  a land
application  system has not yet been conducted under the mandatory VE program. The
capacity of  the wastewater  treatment facilities studied  in  the VE program ranged
from 1 mgd to  160 mgd  average daily flow, as shown in more detail on Table 2. The
estimated pre-VE construction  costs  ranged from   about  $3 million  to  $250
Number of
projects Treatment plant size
evaluated < 1 MGD
1-10 MGD
10-50 MGD
>50 MGD Outfall or P.S.
— — _
1 1
_ _ _
- _ _
2(2) - 2
_ _ _
— — 1
_ _ _
6(2)     1
lumber in parenthesis  designates  number which include AWT.

     The  wastewater  treatment  and  solids  handling  process  and  miscellaneous
facilities  included in the VE  studies  are presented  in  Table  3. This  shows the
large variety  of  treatment processes that have  been evaluated over  the past few
years  under the  mandatory VE  program.  By  far  the majority  of the  wastewater
treatment plants  were  activated sludge systems  designed to produce  better than
secondary effluent  quality,  typically 20 mg/L BOD5 and 20  mg/L  suspended solids
or  better.   Solids  handling  generally  centered  around  waste  activated  sludge
thickening,  anaerobic digestion, sludge dewatering and landfill of the stabilized

                       EVALUATED IN VE PROGRAMS     	   .	
Wastewater treatment
                               Solids handling
                                                               Mi s ce1laneous
Flow equalization
Flow measurement
Grit removal
 ' • Aerated         '   •. •
  V Constant head
  • Constant velocity
Influent pumping
  • Electric driven
  • Engine  driven
Primary sedimentation
Biological  treatment
  • Activated  sludge
  • Trickling  filter
  • Rotating biological
  • Pure  oxygen
 Secondary sedimentation
 RAS pumping
 Effluent  filtration
   • Chlorine
   • Ozone
   •  Chemical addition
   • PhoStrip
 Raw sludge pumping
 Gravity thickening
 WAS pumping
 WAS thickening
   • Dissolved air
   ซ Centrifuge
   • Belt press
 Sludge stabilization
   • Anaerobic digestion
 /  • Aerobic digestion
   • Lime addition
 Sludge dewatering
   • Vacuum filtration
   • Belt press
   • Centrifuge      :
   • Pressure filtration
 Sludge conditioning
   • Heat treatment
   ป Chemical addition
, Incineration
 Land disposal
   • Liquid
   • Dewatered
 Transport        .  :
   • Pipe
    • Truck
Odor control  :
  • Chemical ••.; ,
  • Activated Carbon
  • Organic removal
    tower  .   ,
Garage/shop bldgs.
Administration bldgs.
Site configuration
  • Facility locations
  • Roads
  • Landscape  ...
Construction Methods/
Control Systems
  • Computer
  • Analog
  • Manual     ...  .  •
Electrical  systems
Yard piping-
Site lighting
      The scope  of  the  VE studies did not  show any consistent pattern  related to
 project size  or complexity.  The majority of the VE projects consisted of  only a
 single workshop with  a  single team. Many .projects had  two workshops and  rela-
 tively  few projects  were subjected to  three or  more workshops.   In  general,
 multiple  teams were provided by  large design firms  and  single  teams by  small
 firms.                                           ,

   The  timing of  the workshops  is a critical element  of  a successful  program,
 especially for projects  with a single  workshop.   The  early workshops offer  the
 greater  potential for savings even though  details of  construction  or equipment
 selection  cannot  be  evaluated at  this  stage.  The later  workshops offer  lower
 potentials for  savings because recommended changes are of smaller magnitude since
 the  study  emphasis is  on process equipment arid constructability of the project. A
 majority of the VE reports evaluated were held early in the design stage as shown
 in more  detail  in Table  4.

Number of
Number of
Stage of design completion of
    The  enormous  number  of  individual  recommendations  from  75  VE  projects
required a selection  system to reduce the number  of  ideas  to a manageable level.
The criteria used  in  the  selection systeme are listed below:

          Estimated savings -  Initial and life cycle costs
          Widespread  applicability
          Technical validity
          Minimization  of overlap between projects (same idea not  evaluated for
          more than one project)
     •    A minimum  of 1 idea  from electrical and  architectural disciplines per
          VE contract (where possible)

     Only the first and  last criteria represent an absolute selection. The latter
item was included  in  order  to  include at least a certain number of ideas in areas
where the savings  have been small in terms of absolute dollars, at least relative
to the potential savings  associated with equipment or concrete changes. The other
criteria were included to eliminate "one-of-a-kind" recommendations that may have
saved a great amount  of money  on  one project but which are not widely applicable.
These criteria  were   an aid to selecting  the best  10  to 15 ideas  (if possible)
from each workshop out of  a total in the range  of 5  to 60  ideas.  In  the first
instance, as few  as  1 or 2 have  been included,  but in the latter  instance maybe
as many as 20 were included. The intent was  to present a representative sampling
of ideas from each VE project,  yet not  to present the same idea more than once.

RECOMMENDATIONS ON CONDUCTING  VE  STUDIES                                         •

     The VE  reports  examined for this publication  clearly demonstrated that many
positive benefits can be  achieved from  the  use of  VE  studies.  VE  serves  as a
mechanism  to enhance the  design  of wastewater treatment facilities by providing
the project  designer with  an opportunity to  utilize  the knowledge and experience
of other individuals  to  optimize  the  project  design.                            ,

     The review of  the  VE reports,  as  well  as  interviews and  discussions with
various EPA  Regional VE Coordinators,  State  personnel,  and  firms experienced  in
conducting VE  studies,   formed  the  basis   for  the  following  recommendations.
Appendix A of; this publication contains detailed discussions  of the data used  to
formulate  some  of thes recommendations.                •,,..'

     *     VE teams should closely  follow  the format for, VE  reports presented  in
           the EPA Manual on,"Case Studies and Formats", MCD 27. Such  standardiza-
           tion  of the  VE  reports will  facilitate  review and  approval  of  the
           reports.           .••-•'    -.--,.,...    ..-,-.-  .  : .  ,   ,

     •     The number of firms represented on  a VE  team should  be  minimized  to
           improve the team's  productivity.  VE  teams that include  more  than  one
           consultant firm tend to  be less creative  than VE  teams  from  a  single
           firm.                         :"''''"          .      ,        ...

   '  ซ     It is advantageous  to  the designer  and owner not to  use individuals
           from the designer's  firm on the VE team,  since VE teams not related  to
           the designer's firm provide greater originality, creativity, and  oppor-
           tunity  for cost savings. However,  in  the instances where the team must
           use personnel from  the  designer's firm,  the team coordinator and  at
           least two  other  members should be from another  firm.

     e     VE teams should recommend only those ideas that they would  implement on
           their own  designs. This approach would eliminate the tendency to  recom-
           mend unproven  ideas.

     e     Each VE recommendation should include only a  single "idea. Several  ideas
           in a recommendation may  result in  many  good  ideas  being discarded  due
           to the  rejection of one idea in the recommendation.  -.--•-

     ป     The VE teams  should spend sufficient time   on  each  recommendation  to
           carefully  and  thoroughly develop it. The recommendations  should include
           all assumptions  and computations  for capital,  operating,  and  mainte-
           nance costs.  Each  recommendation  should be  clearly and concisely pre-
           sented  in  the  VE report.

     o     VE team members  should have  attended  a  40 hour  VE training workshop.
           However,  this  training should not be a rigid  prerequisite for team mem-
           bership since  the success  of  a VE  study  is ultimately  dependent  on  .the
           pertinent  experience of individual team members.

     ซ     VE teams  should  include at  least two  sanitary engineers since  this
           engineering discipline  normally  has principal  control  of   over   70

percent  of   the  construction  costs   of   a  project.  Two   sanitary
engineering  team members will enhance  the  opportunity  for  interaction
and creativity during the VE  study.

If only one VE study is  scheduled  for  a project,  it should  be  conducted
during  the  20 to  30  percent  design stage  to  obtain  maximum  benefits
from the study.

                                                                   BASINS & TANKS
                                    CHAPTER  2 _^_

                                BASINS  AND TANKS

Replace Circular Final Clarifiers with  Rectangular Clarifi'ers

     The original concept proposed  three  100-foot diameter final clarifiers, with
     a fourth  clarifier  to  be added in the  future. The sludge  collection equip-
     ment was center column support, rapid removal type.

     The proposed  concept would use rectangular final clarifiers  with traveling
:     bridge  suction sludge  collectors.  The  tanks  would be  constructed with  a
     common wall to the  aeration tanks and contain  channels  for influent distri-
     bution, sludge collection,  and effluent  channels.             -.'.---.

Fewer Passes in Chlorine Contact Chamber

     A baffled chlorine  contact tank was designed with four  baffles,  which pro-
     duced five passes  through the  tank. The thickness of the  interior baffling
     walls was,the same as the  exterior walls of the contact  tank.

     Use of  three passes was recommended which eliminated  two of  the baffling
     walls. The thickness of  the baffling walls was also reduced.

Reduce Depth of Equalization  Basin

     A flow equalization  basin  was  designed  with a depth of 25. feet.

     Because of difficult subsurface conditions, a  shallower  depth basin with an
     equivalent volume resulted in  a lower  initial  cost.  A basin with  a depth of
     16 feet was recommended.

Change Aeration Basin Side Walls from Wye Wall to Tee Wall

     Originally, the aeration basin side walls were designed with  a wye config-
     uration at the top,  and  with the main air header located in the wye.  Alumi-
     num access plates were used over  the Wye opening.

     The proposed concept used  tee  walls, with the main air header hung under the
     head of the tee on one side. This  main  header supplied air for the basins on
     each  side of the wall.  Sketches  of  the  original  and proposed concepts are
     shown in  Figure 1.

Rearrange Basins to Reduce Length of Dividing Wall

     The original design  of the flow equalization basins involved the use of four
     separate, parallel  basins. Each basin had separate  feed and withdrawal pip-
     ing. The  walls were  sheet  pile dividers  with walkways on top.

                                        BASINS & TANKS
 ซ• .•
              •V7-7 —^
                   — AIR HEADER
Figure 1.  Change wye wall to tee wall.

                                                                   BASINS & TANKS
     The proposed  concept recommended  that* the  four  basins be  arranged into  a
     square configuration using sheet  pile wills. The  basin would  intersect  in
     the center of the  square  shape where a distribution  structure  would distri-
     bute and collect the flow and  also house  the sump pumps. Vehicular access  to
     this point would be  accomplished by using a dike substituting  for one  sheet
     pile wall and protruding to the  center of the  basin.  The recommendation also
     eliminated 1000  feet of sheet pile from  the  original  design.  Original, and
     proposed concepts  are shown in Figure  2.                     _

Change Circular Clarifiers to Square  Clarifiers           ,

     The original  design for  the  primary  and secondary  clarifiers  was circular
     with circular sludge collection  mechanisms.

     The proposed  concept used square  shaped  basins with  circular sludge collec-
     tion mechanisms. The basins were  constructed  with  common  wall  construction,
     also allowing equipment and pipe  galleries  for easier  access  for operation
     and maintenance. Sketches  of the  original and proposed system are shown  in
     Figure 3.                                              ;                   ,

Change Rectangular Clarifiers to Square Clarifiers

     The initial  design included rectangular  primary clarifiers  with  flight and
     chain  sludge collection  mechanisms.  Scum removal was  by low pressure air
     through directional  headers.

     The proposed design suggested  the use  of square primary  clarifiers with
     common  wall  construction.  A  gallery  between  the  clarifiers doubles  as the
     raw sludge  pumping  station and  a pipe .chase.  A  sketch of  the original and
     the proposed  design  is  shown  in  Figure 4.

                                                            BASINS & TANKS
                          ORIGINAL CONCEPT
                          PROPOSED CONCEPT
         Figure 2.  Reduce length of dividing walls.
Y /





                                                                BASINS &. TANKS
                                                                Shape -.-".'•
           RAW SLUDGE
      RAS & WAS
                              ORIGINAL CONCEPT
                                 ACCESS AND


/ rit-c. i3Mi_i_cni ?
• \



         ACCESS AND
         RAIN SLUDGE
                              PROPOSED CONCEPT
           Figure 3.    Square clarifiers-instead of circular,.

                                                                     BASINS & TANKS
  RAW SEWAGE                  /
                         EFFLUENT CHANNEL


J /




                  PIPE GALLERY
                              ORIGINAL CONCEPT
                    RAS PUMPING STATION
                    AND PIPE GALLERY WITH
                             AERATION BASINS
                                                       SECONDARY CLARIFIERS
                              PROPOSED CONCEPT
          Figure 4.  Square  clarifiers instead of rectangular.

                                                                   BASINS & TANKS
SIZE                             .

Reduce the Diameter and Depth of Primary Clarifiers                     ,

     The original  design concept  used  three .130'. diameter circular  clarifiers.
     Clarifiers were center fed, center well units with  two scraper arms and each
     was equipped with a  scum  skimmer.  The surface loading rate  for  the original
     clarifiers was 577 gpd/ft^.                   ,                           •

     In the  proposed concept  the surface  overflow  rate  would  increase to  800
     gpd/ft2, which  would reduce  the clarifier  diameter  from 130'  to  117'  and
     the depth from 12' to 10'.

Reduce the Number of Intermediate Clarifiers

     The original  concept specified  use  of  four circular 140'  diameter  center
     well clarifiers.     '                                        *

     In the proposed concept,  the  original surface loading rate  and  solids  load-
     ing rate would be retained, but  the number of clarifiers  would be reduced to
     three by increasing  the clarifier diameter from  140'  to 162'.

Reduce Final Clarifier Depth

     In the original concept  the sidewater depth  of  the final clarifiers was  12
     feet.  Sludge was to  be removed using  rapid sludge removal equipment.

     The proposed  concept decreased the final clarifier depth by  two  feet.  With
     the rapid sludge  removal  equipment in  the  tanks,  the sidewater  depth  could
     be reduced to 10 feet without loss of removal efficiency.

Enlarge the Clarifiers to Eliminate Need for Filters

     The original  design proposed construction of  four  100 foot diameter  clari-
     fiers followed by effluent  filters for additional suspended  solids removal.

     The proposed  concept recommended constructing rectangular clarifiers with an
     overall 32%  increase in  the  volume. This  increase  would be sufficient  to
     improve suspended solids  removal to  a  level  which  would . eliminate the need
     for effluent filtration.

                                                                  BASINS & TANKS

Replace Structural Steel Framework with Precast Concrete TEE  Sections

     Three large diameter  trickling  filters  were  to be constructed with  an  outer
     structural wall consisting of corrugated  steel sheets  supported by a cor-ten
     steel framework.

     It  was  proposed  that prestressed concrete  TEE  sections  be utilized  as  a
     substitute wall material.  To assure  a  waterproof seal,  a  membrane liner  was

Change Material for Sluice Gates

     Originally,  sluice gates  were  designed  to  be  constructed  from cast  iron,
     with either bronze or stainless steel trim.

     Heavy duty aluminum  sluice  gates trimmed with  polyethelene were proposed.
     Stainless  steel stems with crank  operation were  also  recommended.

Change Basin Liner from Permeable Asphalt  to Gunnite

     Flow  equalization basins  were  to  be constructed  using an  earth  structure
     concept  with  a  permeable  asphalt  coating.  This  method  of  construction
     required  an expensive  sub-base,  which was  planned  to  consist of  a  4"  AC
     pavement on a 20" aggregate  base.

     The proposed concept recommended using  reinforced gunnite  in place of  the
     asphalt  liner.    The  recommended  plan involved  the use  of  3" thick gunnite
     application with  4"  by  4"  wire  mesh and a 4" thick aggregate base.   Although
     the gunnite would not  be  able  to  withstand  vehicular  traffic,  vehicular
     access  to  the  bottom  of  the  basin* was not considered  necessary  in this

                                                                   BASINS & TANKS
                                                                   Design Concepts
                                   V..K- •  '     3^>-   •       "        '     •
Use Cover Over Grit Channel to Replace Handrails

     Aluminum handrails were planned  for use  around grit removal channels.

     Use of fiberglass panels  over the grit channels were  recommended instead of
     handrails*   According to OSHA  requirements/  if such  covers are  used,  they
     must be in the down position  at  all times  unless they  are attended.

Eliminate Center Walkways

     In the original  design,  each  aeration basin center wall  was'equipped  with a
     walkway and spray' nozzles for'foam control.

     It was recommended that the walkway,  spray header,  and nozzles be' eliminated
     from the center  or intermediate  walls.

Construct 3 Circular  Secondary Clarifiers Instead of 4

     The plant  to be constructed  utilized two-stage biological  treatment,  modi-
     fied  aeration activated  sludge  for the  first stage' "and  suspended  growth
     nitrification  for  the 2nd stage.   Rectangular intermediate  clarifiers  were
     used  after  the  1st  stage,  arid  4-115'  diameter clarifiers  were  recommended
     after the 2nd  stage nitrification.       ~

     The proposed  concept  recommended the construction  of  3-160*  diameter  clari-
     fiers . This change would result  in approximately the same overflow rate, but
     the cost would be  considerably  less for 3  clarifiers  than for 4  clarifiers.
     Although higher  overflow rates  would occur with one  clarifier  out of  ser-
     vice, this was judged to. be acceptable  because effluent storage lagoons were
     available for use in  emergency  conditions.

Above Grade Storage for Backwash and  Pumped  Backwash       •--

     The original  design  of the filtration  system included provisions  for back-
     washing  the  filters  using  gravity  flow,   and  then collecting the  backwash
     water in a sump  under the filter control building.

     The proposed concept recommendated using   pumped backwash from  an  at-grade
     storage tank.  This alternative  allowed  the filters  and the underground back-
     wash water sump  to be raised  to  ground  level.

Use the Interceptor Volume as Part of the Flow  Equalization Basin Storage

     The original  concept  called for  a major flow equalization basin structure to
     retain stormwater flows to the  treatment plant.  Flow was  to be diverted from
     the interceptor  to  this structure  when  the treatment  capacity of  the plant
     was exceeded.

                                                                   BASINS  &  TANKS
                                                                   Design  Concepts
     The proposed  concept recommended using  storage  capacity in the  interceptor
     tributary to  the plant,  with a resultant reduction in the  required  capacity
     of the flow equalization basin.

Combine Chlorine Contact With Post Aeration

     The original  design provided separate chlorination basin, cascade  aeration
     and post  aeration tank  followed by dechlorination  (SO2)  and pH  adjustment

     The proposed  alternative eliminated  the intermediate  cascade aerator.  The
     size of the chlorination  tank remained the same, although  the post  aeration
     tank required enlargement. Common wall construction between the  chlorination
     basin and the post aeration  tank was proposed. The  larger  post aeration tank
     provided  increased contact  time,  increased post  aeration  and  reduced  SO2
     and NaOH requirements.
Figure 5 shows sketches of the original and proposed
Use Outfall as Chlorine Contact Basin

     A chlorine contact  chamber was included  in  the original plant  design  prior
     to the outfall.

     Elimination of the  chlorine  contact chamber was proposed, with  the  required
     chlorine contact  time  being  accomplished  in  the  outfall.  This  concept  was
     feasible  because  the   outfall provided   an  overall  detention  time  which
     exceeded the detention  time  in the planned chlorine  contact  chamber.

Simplify Chlorine Contact Chamber Valving

     A chlorine  contact chamber  was  designed to operate  using serpentine  flow
     through five  channels.   Each  channel was designed with the capability  of
     being fully isolated from the  other channels, which would allow any  channel
     to be taken out of service for cleaning.

     Division of the  chlorine contact chamber  into 2 separate compartments,  each
     with a  five pass  serpentine  flow was  proposed.  This  approach would  allow
     either half of the contact chamber  to be taken out of service,  without dis-
     turbing the other half.  Redwood dividers  were proposed for baffling,  instead
     of the concrete baffle  walls in  the original design.  Sketches of  the origi-
     nal and proposed concepts are  shown in Figure 6.

Eliminate Inboard Launder on Secondary Clarifier

     The initial  design concept  utilized  80'   diameter  clarifiers with a double
     inboard launder.

     The proposed  concept  recommended eliminating the inboard launders and  using
     outboard launders.  Sketches  of the  proposed and original concepts are  shown
     in Figure 7.

                                                              BASINS  &  TANKS
                                                              Design  Concepts
                                            POST AERATION
                        ORIGINAL CONCEPT

                 -."   •      \
                          EFFLUENT LINE
                        PROPOSED CONCEPT
Figure 5.   Common wall construction between chlorination and post aeration

                                                          BASINS &  TANKS
                                                          Design Concepts
     EFFLUENT        _--^-
                        DISC SCREENS
0 — tx
3— IX
^a —
                                   REDWOOD -
                         CONTACT CHAMBER
                          140' CONCRETE
                                               f        I
            tit   tint
         Figure 6.  Simplify chlorine contact tank valving.

                                           BASINS & TANKS
                                           Design Concepts
Figure 7.   Use outboard launders.

                                                                   BASINS  & T ANKS
                                                                   Design  Concepts
Delete Headworks Grease Removal

     In  the  original concept,  grease removal  was  provided  in  a separate  basin
     located between the  grit chamber  and the primary  clarifier.  Also,  grease
     skimmers were included on the primary clarifiers.

     In  the  proposed concept,  the  grease  removal  basin was eliminated,  thereby
     having   the  complete   grease  removal   being   accomplished  at   primary

Reduce Thickness of  Effluent  Storage  Tank Walls

     In  the  original concept the  effluent storage  tanks  had interior walls  18-
     inches  thick.  The  walls were braced at  intermediate points  by  baffle walls
     or  had  no  unbalanced pressure  acting on  them.

     In  the proposed concept  the  walls  were reduced  to  12-inches thick thus
     reducing the volume  of  the  concrete required.

Reduce Clarifier Slab Thickness

     In  the  original concept,  secondary clarifiers were  designed with  a 30-inch
     slab thickness.

     In  the  proposed concept, the slab thickness was reduced to 20-inch.

Use Precast  Circular Tank Walls

     The original concept provided  two primary clarifiers  and  three final tanks
     which  had cast-in-place reinforced concrete  walls  and  effluent  launders.
     The proposed concept would used precast wall panels  either grouted or  bolted
     together  and post tensioned with  wire  strands on the  outside  covered with
      shotcrete. The launder was cast-in-place.

Use Concrete Channel for Aeration Basin Influent Instead  of  Pipe

      In the original concept the influent to  the  aeration tanks was distributed
      by  means  of a concrete box  with sluice  gates and 30-inch pipe  for each

      In the proposed concept a concrete channel with stop plates  would distribute
      the influent to each aeration tank.

 Redesign Anaerobic  Digester Walls and Mat

      The  original  design proposed a 34-inch  thick digester wall which  consisted
      of  28-inch  of  reinforced concrete,  a 2-inch  air  space,  and a 4-inch brick

      The  proposed  design was for a 22-inch thick  wall  consisting of 16-^inch   of
      reinforced concrete and 6-inch  of  insulation.  The  reduction  in  digester wall
      thickness was accomplished   using  tension  rings.   A  parapet  was also

                                                                   BASINS  &  TANKS
                                                                   Design  Concepts
     eliminated  from the  top  of the  digester wall,  and the  digester slab  was
     redesigned to reduce  concrete and reinforcing  steel.  Overall,  an approximate
     1/3 savings in concrete and reinforcing steel  was  accomplished.

Use Single Precast Scum Box                                ,

     The original design  used  a separate cast in place  scum box for each  of  two'
     primary clarifiers.                            ,

     The proposed concept  recommended combining the two scum boxes  into a single,
     precast unit, thereby lowering  the  construction cost and reducing the number
     of control valves required.

Tilt up Baffle Walls in Chlorine Contact Tank                                 - -  _

     The  original concept used conventional  12-inch  thick reinforced  concrete
     walls as baffles in the chlorine contact  basin.

     The  proposed concept reduced  installation time by  using tilt  up  baffle
     walls.  The  walls,  struts and  beams  would be cast on  the completed  floor
     slab, set  up in place,  and welded at  the  base.  Beams  and struts. would be
     placed and tack welded.

Reduce Effluent Wall Thickness

     The original concept utilized concrete channels for collection  of the final
     clarifier effluent. The walls of the  channels  were 12-inch thick.

     The proposed concept  would reduce the thickness of  the  effluent channels to

Use all Steel Effluent Troughs in  Place  of Concrete and Steel Troughs        ;;-

     The original concept  proposed to use an outboard  concrete trough  for a cir-
     cular clarifier as well as an inboard steel  effluent trough.

     The  proposed concept would  use larger diameter steel effluent troughs  and
     eliminate the exterior concrete troughs.                                .

Eliminate Cover  on Aerobic Digesters

     The  original concept included  covering the  existing primary  clarifiers  and
     aerobic digesters.  GaS  under  the covers was to be collected and cleaned for
     odor control purposes.

     In  the  proposed concept  the existing primary  clarifiers and aerobic digest-
     ers would  be utilized without covers  since  odor control was riot a problem in
     the existing facility.

                                                                  BASINS & TANKS
                                                                  Design Concepts
Omit Preareation Basin—Use Preaeration Channels

     In the  original concept,  a preaeration tank  was located  between the  grit
     tank and the primary clarifier.  The  tank  utilized mechanical  aerators  which
     were covered  to capture  and scrub the  air  for odor  control.   The  primary
     clarifiers  also  had  air  collection  and  treatment  facilities  for   odor

     In the  proposed concept,  the preaeration basin were  eliminated  and replaced-
     with an aerated channel.  The channel would have a fiberglass  cover,  but the
     air would not be treated  for odor  control.

Reduce Depth of Slab for Flow  Equalization Basin

     In the  original concept  a rectangular flow equalization basin  was designed
     with a  1.5 ft thick floor.

     In the  proposed concept,  the thickness at  the  center of the slab was reduced
     to 0.5  ft. The  perimeter  footing retained  the  1.5 ft thickness.

                                                               - PROCESS EQUIPMENT
                                                                Flow Equalization
                                     CHAPTER 3  ;•
                                PROCESS  EQUIPMENT
FLOW EQUALIZATION                       "    '         .-.--.- -..-..—	-.-......

Eliminate Flow Equalization Basin                           , ;   -      ..  -,    ซ

     Initially,  flow  equalization basins  were . provided  to  dampen flow  peaks
     influent to a plant.                                        . .         • -

     The proposed . concept  suggested using variable frequency, type pumps with var-
     iable  speed  drives , to limit  the  flow peaks,  eliminating the need .for flow
     equalization basins.                                           ...,,,.

Eliminate Blending Basin                               .           ,  .       ,  ,,

     Flow arrived at the plant through force mains from  a series of" remote pump-
     ing  stations.  A  blending  basin  was  included  in  the  original   design  to
     homogenize  the quality  of wastewater  from  the  different  force mains.  Air
     diffusion was used in the blending basin to mix the basin contents.

     Elimination  of the blending  basin was  proposed,  since  sufficient blending
     would  occur in the grit  removal basin  and the primary clarifier.

Use Interceptor Storage Capabilities

     To equalize  wet  weather  and  other peak flows  through a  plant,  an influent
     storage  basin was  proposed.  The storage  basin would be  located on-site,
     before the raw wastewater pumping facilities.

     An analysis  of the 72-inch influent sewer indicated  that it  contained over
     3.5 mgd  of  usable storage capacity ,at peak  flows,  which was more than  the
     proposed capacity of  the influent storage basin. It was proposed to use the
     storage  capacity  of  the interceptor  and  eliminate  the  proposed  storage
     basins.  Coincidentally,  because the storage  capacity of the interceptor was
     greater  than the  proposed storage  basins,  the required  capacity  of the raw
     wastewater pumping facilities was also reduced.    .

Substitute  Swirl Concentrator for  Flow Equalization Basin       .!.

     The  original concept provided for  flow equalization by  use , of  a covered
     three  cell basin,  with  sludge collection equipment. The basin had  a capacity
     of 5.5 million .gallons.  Coagulants were planned to be added to the equaliza-
     tion basin.           ,                                       . • - '.

     The proposal was  to  use  a swirl  concentrator in lieu  of the  flow equaliza-
     tion basin.  Flows in excess  of plant  hydraulic capacity were  to be settled
     to remove solids,  disinfected, and discharged through a chlorination basin.

                                                                PROCESS  EQUIPMENT
                                                                Flow Equalization
Remove Sludge Collection System from the Flow Equalization Basin

     In the  original concept a covered three cell  basin with  sludge  collection
     equipment  was  provided  for  flow  equalization.   Traveling  bridge  sludge
     collection mechanisms were to be provided to  collect and remove  the sludge.

     The  proposed concept  recommended flow equalization basins without  sludge
     removal equipment. The  sludge would be  removed  manually.

Eliminate Flow Equalization  Basin

     Flow equalization basins were provided  at the treatment plant to dampen flow
     peaks which were caused by several large package lift  stations.

     The  proposed change was  to  use a throttling valve at the lift  station  to
     limit flow peaks,  and  thereby eliminate  the  need for  the  flow  equalization

Use Concrete Lined Earthen Basin

     The  original design  included concrete ' flow equalization  basins  with sub-
     merged  turbine  aerators for  aeration and mixing.

     The  use of concrete lined  earthen basins  of the  same  volume was proposed.
     Because the  project  was upgrading an existing plant, it was recommended that
     the  static tubes  from existing aerated lagoons  to  be  salvaged and used with
     a  new blower to  insure adequate  mixing. The proposed  and original designs
     are  shown  in Figure  8.

Pumped  Mixing  Instead of  Jet Aeration Mixing

     Originally the  flow  equalization basin used a -jet aeration mixing  system.

     The  proposed concept  recommended using pumped mixing to replace  the jet
     aeration  system.

Eliminate Flow Equalization Basin

     In the initial concept flow equalization  was  provided  by a covered  three-
     cell basin  with  collection equipment  provided to  remove  the  sludge.  The
     basin was intended  to  be  used  during wet  weather flow  in excess  of the
     design flow rate. If overflows occurred during  a storm,  they would discharge
     to  the  plant  effluent after  receiving chemical  aids  for  coagulation and
     disinfection. Raw wastewater  remaining after  the  storm would be  treated in
     the plant after influent flow dropped  below  the plant  design flow.  The basin
     was covered  and ventilated  air  from the basin  would  be treated by  chemical

      In  the  proposed  concept,   the  flow equalization  basin would  be  completly
      removed and influent  in  excess  of  plant  design  would be  chlorinated and

                                                              PROCESS EQUIPMENT
                                                              Flow Equalization
                                                                PROCESS EQUIPMENT
                                                                Flow Equalization
Eliminate Flow Equalization Basin  Cover
     In  the  original concept  a covered three-cell  basin with  sludge  collection
     equipment was provided  to receive wet weather  flows  in  excess  of  the design
     flow rate.

     In  the  proposed  concept the  flow equalization  basin  was  designed without
     roof  or  odor   control.  Odor  control  for   the   equalization  basin  was
     unnecessary  due to  the  infrequent usage and  the short  periods of  time it
     would be used.

                                                      PROCESS  EQUIPMENT  ''-
                                                      Pumps -  Influent & Effluent
PUMPS - INFLUENT AND EFFLUENT                ,                      .

Revise Inlet Direction into Pumping  Station

     A large effluent pumping  station  used a rectangular wet well and five pumps.
     The wet  well was arranged in  a  manner which  required flow  to make  a  90ฐ
     change in direction before  reaching the pumps.

     A re-arrangement of the  wet well  was proposed which  would equalize the flow
     to  each  of the pumps and  eliminate potential dead  spots in the  wet well.
     The  re-arrangement was   based  upon  Hydraulic  Institue  Standards for  wet
     wells, and  eliminated the  90ฐ  change'.  in  direction in  the  original design.
     Figure 9 shows sketches  of  the  original and proposed concepts.

Delete Redundant Wet Well  Dewatering Systems

     A  large interceptor  pumping  station   was  designed  to handle  separate  wet
     weather flows and dry weather flows. The  pumping station was designed  as two
     separate pumping stations  in  one structure. Separate  wet wells,  pumps,  and
     discharge piping were provided for wet weather  and dry weather flows.  Pro-
     vision  was  made for  separate  dewatering  systems  for  the wet  weather pump
     sump  and  dry weather pump  sump when systems pumps were not  in operation or
     were  down for repairs.

     Use of a single  sump dewatering system  for both  the wet weather and  dry
     weather pumps was proposed, thereby eliminating one of the original dewater-
     ing systems.

Variable Speed and Constant  Speed

     The original design concept used four variable speed pumps in the  raw  sewage
     pump  station.    The pump  station was  planned  to  pump an  equalized flow of
      12.5  mgd.                                                                     .

     The proposed change  modified the  system  to utilize two  constant speed and
      two variable speed drive pumps.  The constant speed  units would be sized to
     pump  the average flow rate while the  variable speed units  would be used to
     pump  the  additional flows.

 Right  Angle Drive Instead of Horizontal Drive

      The original concept proposed  five gas engine  drives  for the  influent pump
      station.   The pumps and  gas engines were both located  below grade  in  the  dry
      well, thereby allowing horizontal drive between the  engines and pumps.

      The  proposed  concept recommended the  installation of  the  gas  engines at
      grade, with a right angle  gearbox  to transmit power to the pumps.  The pro-
      posal significantly  reduced the  dry well  size.  Simplified  sketches  of  the
      original and proposed designs  are  shown in  Figure 10.

                                     PROCESS EQUIPMENT
                                     Pumps - Influent & Effluent
                   O    Q   O
                                            7) INFLUENT
                         WET WELL-PLAN VIEW
Figure 9.  Revise inlet to pumping station.
t?        V

                                     PROCESl EQUIPMENT
                                     Pumps - Influent & Effluent





k 1




                ORIGINAL CONCEPT
                 RIGHT ANGLE DRIVE
                                      GAS ENGINE
                                     \DRY WELL
               PROPOSED CONCEPT
Figure 10.   Right angle drive system.

                                                      PROCESS EQUIPMENT
                                                      Pumps - Influent & Effluent
Four Pumps in Place of Five

     In the original  concept five raw wastewater pumps,  each sized  at  7,900 gpm
     were proposed for the influent pump  station.

     In the proposed  concept four raw wastewater pumps,  each sized  at  9,900 gpm
     would be utilized.
Combination of Gas Driven and Electric Driven Pumps

     The original concept used  five  gas  engine driven pumps  (each  150 HP)  in the
     influent pump station.

     In the proposed  concept two  gas  engine  driven pumps  and three  electric motor
     driven pumps, each  150 HP, were  used. Two of the three electric  driven pumps
     would have variable speed  controls.

Vertical Pumps in Place of Horizontal Pumps

     The original concept  proposed using a  primary  pump station with four hori-
     zontal constant  speed pumps^to pump  13  mgd average  flow to  the primary clar-
     ifiers. The horizontal  pumps were located  in a dry well with a superstruc-
     ture constructed above  the dry well to  house the motor control  center, air
     compressors, stairwell, and  equipment hatches and overhead  hoist.

     The proposed concept would use  either three or  four vertical  pumps in place
     of the horizontal pumps,   thereby allowing a reduction  in  the dry  well and
     building size.

Prefabricated Pump Station for  Cast-In-Place Pump Station

     In the original  concept,  the designer proposed  a cast-in-place  pump station
     with four horizontal  constant speed pumps. The  station  capacity was 13 mgd.
     The horizontal pumps were  located  in a dry well, and  a  building was located
     above  the  dry  well to  house the  motor  control center,  air  compressors,
     stairwell, equipment hatches and overhead hoist.

     The proposed concept would use a prefabricated  pump  station with four verti-
     cal pumps. The package pump  station  with adjacent wet  well  would contain all
     the pumps,  controls,  appurtenances, and elevator access to the  below grade
     pumping facility.

Vertical Propeller Pumps in Lieu  of Screw Pumps

     The  original  concept proposes  a secondary  effluent  pumping  station  using
     72-inch  diameter screw pumps each  having a capacity  of  17,000  gpm  and  a
     lift of 20 feet.

     The  proposed  concept used  vertical propeller  pumps  with  a  simplified but
     deeper wet well.

                                                      PROCESS EQUIPMENT
                                                      Pumps - Influent & Effluent
Switch Sizes of Variable Speed and Constant  Speed Pumps

     A raw wastewater pumping station was  to be  constructed with 120 mgd of pump-
     ing capacity. Two 40 mgd variable  speed pumps were  to be used-in conjunction
     with two 20 mgd fixed speed pumps.

     As a greater  percentage of flow occured  in  the lower. flow  ranges,  an over-
     all increase  in pumping station efficiency was proposed  by  the use of fixed
     speed  pumps  to  handle the  lower  flows and  variable  speed  pumps  for  the
     peaks. Two 40 mgd fixed speed pumps and two 20 mgd variable speed pumps were
. :    proposed.

Fixed Speed Pumps  for Variable Speed Pumps                                 ,

     Four raw sewage influent' pumps• we're .called  for, each designed  as a variable
     speed unit.                               " .        | .•.-"•...•.-•.•

     Two variable  speed  and two constant  speed pumps were proposed .to eliminate
     the need for  two  100 HP magnetic  drive  units.

Combine Separate Effluent and Storm  Water Pump Stations into One Station

     In the original  concept there were two  60 mgd pumping stations,  one for the
     plant  effluent, and  one for a storm-water channel  located on the .plant site.
     Both  stations pumped flow  to  an  adj acent  river and  both  had approximately
     the same discharge .head.              •

     It was proposed that  these  two pumping  stations  should be combined into  a
     single structure, with use of the same pump (20 mgd)  as  the standby for both
     facilities.   Aspects of- the proposal were  the use of common  wall construc-
     tion,  a  savings  in electrical power  distribution  facilities,  and an overall
     reduction  in  .excavation.           , ,              ..

Cooling Water Pumps for  Diesels

     A large  effluent  pumping station  used  two  diesel  engines to drive two pump-
     ing units.  Cooling water for the diesels was provided by three  (one  standby)
     electrically-driven cooling water pumps.  In  the  event  of  a  power  failure,
     the  plant - did have standby .generation capability,  which would  be  able  to
     supply power- to  the electric motors driving the cooling  water pumps.

     The  proposed concept recommended  driving the  cooling water pumps by a  gear
     drive from the diesel  units.  One  cooling  water pump was  proposed for  each
     diesel,  eliminating the standby pump in the original  design. The three elec-
     tric  motors in the original design were also  eliminated.

 Substitute Screw Pumps for Vertical Propeller Pumps           ,

     Effluent pumping to  a nearby  river  was .planned  to  be  by  a  60 mgd  pumping
      station  which would use four 20 mgd vertical  propeller pumps.

                                                PROCESS EQUIPMENT
                                                Pumps - Influent & Effluent
Screw pumps  were proposed  as a  replacement,  using  3  installed at  20 mgd
each, with one 20 mgd standby pump.

                                                               PROCESS  EQUIPMENT
                                                               Process    •

Change Suction and Discharge Valving

     An effluent pumping  station was  designed with manually operated gate valves
     on suction and  discharge  lines,  and a  24-inch  check valve on  the  discharge

     A proposal was  made to substitute  butterfly valves  for  the gate  valves  on
     the influent and effluent lines.  Also,  replacement of the  check  valves  on
     the effluent lines with motor  operated  butterfly valves was proposed.
Vertical Turbine Pumps to Eliminate Dry Well
     Effluent  pumping was originally  planned to be  by use of  centrifugal mixed
     flow  pumps.   Pumps were  located in  a dry well  and  drew suction  from an
     adjacent  wet well.

     To  eliminate the need  for the dry well, vertical turbine pumps were proposed
     instead of the  centrifugal mixed flow pumps.   The vertical  turbine pumps
     would be  located directly  above  the  wet well.  The  proposal  eliminated the
     dry well  and   considerable amount  of  suction  valving.  Schematics  of  the
     proposed  and original  concepts are shown in Figure 11.

 Add Influent Pumping and Eliminate Effluent Pumping

     Influent  wastewater flow to the plant  was  by  two  conduits, one a force  main
     and the other  a gravity interceptor,  the .latter carrying less than half the
     - influent  flow.  Due to  the plant layout,  and elevation,  a portion  of the
     available head, in the  force main was lost at the headworks. The plant layout
     required  a low lift pumping station for the plant effluent.

     The  proposed  concept  recommended  some minor  plant  layout  changes which
     resulted in raising the  headworks elevation and  utilization  of the  head  in
     the influent force main  flow.  This  change  also necessitated the addition  of
     a  screw  pump  to  boost  the  flow from the gravity  interceptor to  the new
     headworks elevation. The proposed changes,  allowed gravity  discharge  from the
     plant, eliminating the need for an effluent pumping  station.

 Smaller Influent Pumps with a Pump Added in the Future

      The  original  concept called'' for three influent 'pumps  of 33.6,  38.5,	and
    •  39.5 mgd. The pumps were" to  utilize wound rotor motors with  liquid  rheostat

      The proposed concept suggested the ^initial installation  of 3  pumps of 24 mgd
      each,  and  the  addition  of a forth 24  mgd pump  12 years  in the  future,  when
      influent  flows projection dictated  such an  addition.  The proposed  concept
      also  included  use  of frequency change for  motor speed,control and  the use  of
      squirrel cage motors.

                                                   PROCESS EQUIPMENT
                    !>-  MOTOR
               ORIGINAL CONCEPT
              PROPOSED CONCEPT
Figure 11.   Vertical turbine pumps.

Use Self-Priming Pumps

     The original design  for  the  sludge  pumps  used  centrifugal pumps located in a
     dry pit. The design  also  included an  upper  level  building above the pit.

     The proposed  concept recommended using self-priming pumps located• at  grade
     to eliminate the dry pit at the decant .pump station.  The recommended system
   '  eliminated  the  dry pit,;  reduced piping,  and eliminated  building  and venti-
     lating requirements.  ,           ,

Use' Return Pumps for Wasting  Sludge              ,

     In the  original  design/  separate pumps were  use  for  return  and waste  acti-
   •  vated sludge.                              ,    '                 •          •

     The proposed  concept recommended using the return pumps for both returning
     and wasting activated sludge.
   '•                                                •                  '
Combine Primary  Effluent and  Biofilter  Recirculation Pump Stations

     In  the  original design,  a pump station  lifted primary  effluent  to the wet
     well  of the biofilter pumping station. The biofilter pumping station pumped
   ;  primary effluent plus biofilter recycle to the top of the biofilter.

     The  proposed concept recommended   combining these  two pump  stations into  a
   ••- single  station in  order to provide  a lower construction  cost, fewer  pumps
     and  simpler operation.  Sketches of  the  original and proposed concepts are
     shown  in Figure 12.                            ,   •

Pump Directly to Biofilter'

     In  the  original .design^ the  primary  effluent  pump  station lifted primary
   ;  effluent to the recirculation pump station which then pumped primary  efflu-
     ent and~biofilter  recirculation to the top of the biofilter.

     The proposed concept recommended reduced the  size of the recirculation pump
      station and increased efficient energy use when  it recommended pumping pri-
   •  mary effluent directly to the  biofilter  using the primary effluent.pump sta-
      tion. The recirculation pump  station would then be  used only  for  biofilter
     ^circulation to  maintain the wetting rate on  the  media.  Sketches of  the
      original and proposed .concepts are shown in Figure  13.

 Use Positive Displacement Pumps at Air  Flotation Thickeners                      ;

      The  original  concept  used recessed impeller pumps  to  pump  air  flotation
      thickened sludge from a  wet well to  subsequent dewatering.

      The proposed .concept recommended  positive  displacement  pumps. It  was  noted
      that experience  with the original  pumps  indicated  that recessed  impeller
      pumps would air lock when used in  this application.

                                                        PROCESS EQUIPMENT
       Figure 12.  Combine pumping stations.


                                                            PROCESS EQUIPMENT
                   ORIGINAL CONCEPT
     PoSo ~	
                   PROPOSED CONCEPT
 Figure 13.  Pump primary  effluent directly to bio-filters.

                                                                PROCESS  EQUIPMENT
Substitute Centrifugal Returned Activated Sludge Pumps  for  Screw Pumps

     In  the  original  concept,  screw pumps  were specified  for return  activated-
     sludge pumping  to a channel  and hence  to the  aeration basin. Pump  control
     was to be by either speed control or wet well  level  control.

     In  the  proposed concept, centrifugal  pumps were  provided for return  acti-
     vated  sludge  pumping.  Speed  control  or  discharge   valve  throtting  was
     proposed for rate control. Figure 14 shows before  and  after sketches.

Vertical Mixed Flow Pumps for Return Activated Sludge

     The  original concept  used horizontal  single  stage  centrifugal  pumps  for
     return activated sludge. Four pumps were  to  be used with one  to be  added in
     the future. A wet well/dry well pumping station was  planned.

     In  the proposed  concept,  pump* selection was  changed to vertical mixed flow
     (wet pit) pumps  and the building size was reduced.  The dry well was  elimi-
     nated in  this concept. Figure  15  shows  sketches  of  the  original  idea  and
     proposed idea.                                           ,   .   ;

Use Variable Speed Vertical  Mixed  Flow Pumps for Filter Influent

     The original  concept  called  for four screw pumps  to.lift  final effluent to
     the tertiary filters. The pumps were located  at the  tertiary filter building
     and the screws  are  exposed to the weather  while  drives and pump discharges
     were enclosed in a building.

     The proposed  concept  used four vertical  pumps driven  by  variable  frequency
     drives. The  pumps and  drives were  enclosed  in a smaller  building while  a
     portion of the wet well was exposed to  the weather.  Figure 16  shows sketches
     of the original and proposed  concepts.

Vertical Turbine Pumps in Place of End Suction Backwash Pumps

     The original concept uses ,3 - 7200 GPM  end suction backwash pumps.

     The proposed concept recommended using  2 -  10,000  GPM  vertical turbine back-
     wash  pumps  with  separate   backwash   supply  and  backwash  waste  headers

Use Vertical Pumps Instead of Horizontal Pumps

     The original  concept  used horizontal centrifugal pumps for return  of  nitri-
     fied  secondary  effluent and" nitrified return  sludge.  Pumping head was  21"
     Use  of  vertical  mixed  flow pumps  in  the  return
     recommended to eliminate  the  dry well.
sludge  wet  well  was

                                                              PROCESS EQUIPMENT
                                                     CHANNEL TO
                                                     AERATION BASIN
                         ORIGINAL CONCEPT
                         HAS PUMPING



: <
                                            AERATION BASIN
                         PROPOSED CONCEPT
 Figure  14.   Use mixed flow pumps in lieu of screw pumps.

                                                                 PROCESS EQUIPMENT
                                              RETURN SLUDGE
                           ORIGINAL CONCEPT
                                       RETURN SLUDGE PUMP

                                       MIXED LIQUOR
                                            STAIRS IN THIS AREA
                          PROPOSED CONCEPT
             Figure  15.   Use  vertical mixed flow pumps.

                                                                PROCESS EQUIPMENT
                                                                Process       ,
                                                   SCREW PUMP ROOM
                         ORIGINAL CONCEPT
                         PROPOSED CONCEPT
                                                       > FILTER

Figure 16.   Use vertical mixed flow pumps instead of screw pumps.

                                                               PROCESS  EQUIPMENT
Eliminate Digester Sludge Transfer Pumps

     In the original design,  two  pumps were provided to transfer sludge  from  one
     digester to another.

     The proposed  concept  suggested  eliminating  the  sludge  transfer  pumps  and
     using  the  recirculation  pumps for  the  transfer  operations.  The  proposal
     eliminated  building area  and  simplified piping.  Although  the  transfer  of
     sludge would  take  about four times  longer  using  the recirculation  pumps,
     this  was not  considered  to be  critical  since  transfer  of  sludge  is  an
     infrequent operation.             •

Use Aluminum  Zip-Rib Instead of  Aluminum Checkplate for  Covers on Pump Station
and Pretreatment Complex                                             *>•

     The initial design used 3/8" thick  aluminum checkplates to provide walking
    > surfaces above  all channels and  basins  in  the raw  sewage  pumping  and  pre-
     treatment areas.

     The proposed  concept  recommended a  lightweight  cover  system  of  aluminum
     zip-rib. In the area  of  the comminutors and flumes, the  aluminum  checker-
     plate covers were  retained to allow unrestricted access  for plant personnel
     and the public  as  a viewing  platform during tours.

                                                                PROCESS EQUIPMENT
                                                                Flow Measurement

Eliminate .Flow Meter

     Flow to a  chlorine contact chamber  was  originally through an  84-inch pipe,
     which was split into 2-54" pipes  for diversion to  two separate  chlorine con-
     tact chambers".   A. metering pit  was  to be  provided with  valves and  flow
     meters to divide the flow between the two  contact  chambers./
     Deletion  of the  flow meters  and  associated valving was recommended,  with
     control of the flow split  to be  accomplished hydraulically.

                                                                PROCESS EQUIPMENT
Use Existing Mechanical Screens

     An existing facility  was to be abandoned and a new  1.5  mgd plant was to  be
     constructed a short distance away.   All existing facilities were planned  to
     be abandoned,  and a pumping  station  was  to be constructed  to  pump flow  to
     the new plant.   At the new plant, mechanically  cleaned  bar screens, with  a
     standby manually-cleaned bar  screen  in a bypass  channel,  were included  in
     the design.

     Continued use of the  existing manually cleaned  bar  screens at  the  existing
     plant prior to pumping to the  new plant was  recommended.

Eliminate Screw Conveyor

     The original headworks  design provided for screenings to be discharged  from
     three bar  screens onto  a belt conveyor.  The belt conveyor discharged  into
     the hopper of  an inclined screw conveyor.  The  screw conveyor dewatered the
     screenings and discharged to  a screenings bin for  transportation by forklift
     to the energy/solids building.

     It was recommended to  eliminate the screw conveyor and extend the  belt  con-
     veyor to  discharge directly  into  the bin.  The  bottom of  the  bin would  be
     perforated to permit the screenings  to  dewater to  the  floor drain  below.

Haul Screenings to Sanitary Landfill           '

     The original idea was  to incinerate  screenings on  site at the plant.

     The proposed concept  recommended reducing the energy  requirements  by  elimi-
     nating  the incinerator  and hauling  the  screenings directly  to a  landfill
     where odor would not be  a problem.

Use Mechanical Screen Instead of  Barminutor

     The original design included a barminutor  in the head  works.

     The proposed concept  recommended using  a mechanical  screen.

Eliminate Standby Mechanically Cleaned Bar Screen

     The  headworks  was designed  with two mechanically cleaned bar  screens  each
     having capacity  for the  entire plant flow.   One of the  screens  was  for  nor-
     mal operation and one  was for standby.

     The proposed concept  recommended that  the  standby screen be converted  to  a
     manually cleaned screen.

                                                                PROCESS EQUIPMENT
                                                                Grit Removal

Grit Removal Channels in Lieu of Pista Grit Chambers

     As  originally  designed,  two  pista  grit chambers  were  provided for  grit
     removal. An  airlift was used  to  lift grit from each  chamber into a slurry
     pipe for conveyance to a container.

     The  proposed  concept  recommended  using  four grit  channels  approximately
     eight feet wide by 50; feet  in  length.  The grit would be  handled using con-
     ventional  collectors,  conventional  grit elevator,  and  conveyed  using  a
     screw-type  conveyer.    Sketches of  the  original  and  proposed,  concepts  are
     shown in Figure 17.               •                   '..'..'

Delete Grit Washer  and Pump Directly to  Sludge Storage  Basin

     As  initially designed,  the grit handling system included pumping grit from
     an  aerated  grit chamber to a  grit  washer and a_ grit  cyclone.  The grit  was
     then to be hauled to a landfill for disposal.                               ••''••

     To  simplify  the  operation,  it was recommended  that  the   grit be  pumped
     directly to  sludge storage basins, which store  digested, dewatered sludge
     prior to trucking to landfiJLl.  The  proposal  eliminated the need for separate
     grit treatment and hauling.                                       ,

Eliminate Grit Washer and Use Cyclone

     The  original design included  a grit  system consisting,  of  an  aerated grit
     chamber, a grit washer and  a grit cyclone.

     The  proposed concept recommended eliminating  the  washer  and  only using  the
     aerated grit chamber and the cyclone"to  concentrate the  grit.

Replace  Tube Conveyor and Storage with Belt Conveyor  and Dumpster

     The  original design of  the headworks included the use of tube  conveyors to
     transport screenings and grit  to a  storage tank.                      •     .

     The  proposed concept recommended  elimination of  the  silo storage tank  arid
     the  tube conveyor and using a  belt  conveyor and  a  dumpster box.

Eliminate Truck Scale to Measure Grit Removal From Plant Site                   ,

     Trucks  were planned  to  remove dewatered grit  from the  plant  site,  and  a
     •truck scale  was planned for truck weighing.

     Elimination  of the scale  was  proposed  with grit  measurement  to  be accom-
     plished  by  measuring  grit volume  using marks  on the  side  of  the  trucks.
     According  to sand and gravel  haulers,   this  technique  should give about 1%
     accuracy.  The  uniform density of  grit  would  be  beneficial  in  attaining
     accurate  results.  At  the  plant  under  consideration,  scales  were  also

                                 PROCESS EQUIPMENT

                                 Grit  Removal
             <    /
             5   /



                                                                PROCESS EQUIPMENT
                                                                Grit Removal
   • 'available  in the  digester' area*/' -and these  were planned  to -be •• used•  on.' a
     periodic basis to check the accuracy  of  the proposed technique.

Simplify Grit Removal from Primary  Sludge                               ..-'.-'

     Cyclone degritters were planned  for degritting primary sludge. The plant was
     designed with  four primary clarifiers,  four  sludge pumps and  four cyclone
     degritters.  The  primary sludge pumps  were to be  located 600 feet  from the
     cyclone degrittjers.                                  '  ,    .            .      ;

     Use of one primary sludge  pump and cyclone degritter  for two primary clari-
   -  fiers  was  proposed  with  a standby  pump  and  degritter.  Sketches of  the
     original and proposed concepts are shown in Figure 1.8. ,;,

Use Aerated Grit Chamber in Place of Gravity  Grit Chamber

     The  original  concept  proposed   using  a  shallow  gravity grit  chamber  in
     parallel with an existing  unit of the same type.  The  new' grit chamber would
     be built  on a severely sloping  grade,  thus  requiring  foundation  piles  or
   .  other special support;  ,   .-.                      -     •

    , The proposed concept recommended  using an aerated grit chamber to handle the
     entire-design  flow. Because  of the greater depth involved with the aerated
     grit chamber, special foundations and retaining walls were not required. The
     existing gravity  tank  would be  retained for  periods  when the  aerated  tank
     was out of service. ,             ••            .-.'...                       ;

Substitute Low Head Grit Basins for Velocity  Controlled ..  ...

     The  ;original  plan .  used  two   velocity  controlled  grit   basins  and  a;
     barminutor.                        .   t.   • .. .                                -

     The proposed change recommended  using two ''more reliable;'lbw' head grit basins
    •and a mechanically cleaned screen. The proposed system would provide contin-
     uous grit removal and would not  be dependent on/an operator.

                                                 PROCESS EQUIPMENT
                                                 Grit Removal
        8     * 8     ^8      f8


              O   O    O   O

Figure 18.  Simplify grit removal.
                                      PUMPS ON
                                      TIME CLOCK (TYP)
                                            DEGRITTER (TYP)

                                                                PROCESS EQUIPMENT
                                                                Clarifiers   .  ".
CLARIFIERS           '             ..--a*        :M^. ,...,    ....... . „ ..  ,   .,,...;...  ,     ...

Replace Primary Effluent Channel  with Pipe

     Effluent  from the primary  clarifiers originally  was  collected  in  a common
     channel and piped over  an interstage pumping station.

     The proposed  concept  recommended replacing the effluent  channel with a pipe
     and transferring the  effluent directly to the interstage pumping station.  A
     sketch of the before  and after concepts  is shown  in Figure 19.

Eliminate Low Air Pressure Scum Control System

     In  the original  design concept, rectangular  primary sedimentation basins
     were equipped with a  low pressure directional air system to move the scum to
     the head  end of the  basin.   The  basin also  had  an air  scrubber system for.
     odor control. .;•.-•-•••   •'     '   '            •     "

     The proposed concept recommended' eliminating  the low pressure directional
     air system for.  scum removal  and replacing it with .more positive, less energy
     intensive, collection mechanisms using flights or separate drive system. The
     recommended  system  reduced  the  required odor scrubbing  capacity needed for
     the system. Figure 20 shows  sketches of  the original and proposed concept.

Eliminate Settling Tubes in  Secondary Clarifiers

     The  initial  design  of •"-.rectangular- secondary  clarifiers  included   tube
     settlers  in the last  115* of :each clarifier basin.      ",    .

     The proposed recommended eliminating the tube settlers  to  reduce  construc-
   :  tion   and O&M  costs.  Although  some  loss  of  suspended   Solids  removal
     efficiency would occur, the  change was considered negligible.

                                                                  PROCESS  EQUIPMENT
 Primary   """**
                      Effluent channel
                            To interstage P.S.
                  36" Collection pipe
                            • To interstage P.S.
      ——Aeration Basin
        distribution flume
                                                      •Interstage P.S.
                                                        Ba s i ns —,
         "Aeration Basin
          Distribution flume

          Interstage pumps
            Basins -
Figure 19.   Replace primary  effluent channel with pipe.

                                                                    .PROCESS EQUIPMENT
                                                                    Clarlflers , .
                    Helical skimmer
                           4-3" Air headers
                        ORIGINAL CONCEPT
                            Scum trough
                       PROPOSED CONCEPT
                                         Air' from blower
                                                  •Chain & flight
                                                   collectors  ."-".
                                                  Chain & flight
                                                  col lector   ' .
Figure  20.
Replace  low pressure  air scum control system with
collection mechanism.    .                   ;

                                                               PROCESS  EQUIPMENT
                                                               Trickling  Filters

Modify Existing Distributor Instead of Replacing

     An  existing  plant used  a trickling filter  to  treat primary  effluent.   To
     maintain  sufficient  flow through the  distributor  and the trickling  filter,
     the system was capable of up to  50% recycle. Planned upgrading of  the  plant
     by  adding activated  sludge  treatment  after  the trickling filter eliminated
     the capability  of recycling flow through the  filter,  and without  recycle,
     the primary  effluent  flow  was  incapable of  turning  the distributor  arm.
     Plans for upgrading  the plant included a  new distributor arm.

     The proposed concept recommended blocking off two opposing distributor arms
     with  blind flanges,  thereby increasing  the flow  through the remaining  two
     arms by 50%.  The  assumption was made that  the distributor should  turn sat-
     isfactorily with 2 arms  blocked  off,  but  an  alternate solution was  to remove
     two opposing arms.

                                                                PROCESS  EQUIPMENT
                                                                Aeration Systems

Change Air Piping Material

     In the original  design  concept,  a steel cylinder concrete pipe  was  utilized
     from the blower  building to  the  aeration  basins,  with ductile iron pipe used
     for distribution at the aeration tanks.

     A piping material  change from the  steel  cylinder concrete pipe  and ductile
     iron pipe to steel pipe with multiple wrap coating was proposed.

Increased Aeration Basin Depth Change Type of  Diffusers

     An  aeration basin  depth of 15  feet and  fine bubble  dome  diffusers  were

     An  increase in  the aeration basin depth from  15'  to 20' was proposed, and
     change  to  coarse  bubble   static  diffusers  to  increase  oxygen  transfer
     efficiency, and  reduce power costs.

Emergency Drive  of Air Compressors for Pure Oxygen Plant

     Pure  oxygen was to be  generated  on-site  for use  in  secondary treatment.
     Three  20  ton/day units  were planned, two  for  normal operation  and one for
     back-up unit.  Each  of the air compressors  was  driven by an electrical motor
     under  normal operation,  and during  a power  outage, any  two of  the  three
     could  be driven  by  gas  engines.  Digester gas would be used as the gas source
     for these  engines.

     The proposal concept recommended  using  two air compressors, each  rated at
      100% of  required capacity.   A single  gas  engine,  which could drive  either of
     the compressors, was  proposed for  use during power outages.  A sketch of the
     original  and proposed concepts is  shown in Figure 21.

 Use Smaller Blower  for Low Pressure Air Supply

      In the original , concept,  low pressure  air  for  aerating  the aeration tank
      influent and effluent channels  was taken off the high  pressure line to the
      aeration tank.

      The proposed concept recommended two low  pressure  blowers (one or standby)
      with an equivalent reduction in  the main blower size.

 Use Welded Steel Pipe in Place of Flanged Ductile Iron Pipe

      In the original design, pipe from the air blower building was specified  to
      be flanged ductile iron piping.

      The proposed  concept  recommended using  welded steel  or  stainless  steel
      blower piping.       -

                                                              PROCESS  EQUIPMENT
                                                              Aeration Systems
            ENGINE -
                                 • 3 AIR COMPRESSORS-
                         AIR COMP. ROOM
                           FIRST FLOOR PLAN
                            ORIGINAL CONCEPT
                    GAS ENGINE
                            -AIR COMPRESSORS
                      FIRST FLOOR PLAN
                          PROPOSED CONCEPT
Figure 21.  Emergency drive for pure oxygen air compressor system.

                                                                PROCESS EQUIPMENT
                                                                Aeration Systems
Use Plastic Insert type Vehturi  Meters' for Airline .Metering  '"    !  ' ' •*.•;•"=•*•••-:-••'•?•;-?ซ•••-.'••<•.•

     The original concept proposed using venturies on the aeration lines.

     In the proposed concept plastic  insert type  venturies  with a  20  year  life '
     are used for airline metering.

Reduce Number of Blowers, Use Dual Drive, and Increase Speed                      "

     The original concept  for  the aeration  system  was  to use six blowers  operat-
     ing at 1200 RPM. Three  blowers were to be motor driven, two dual fuel (meth-
   ,  ane .and natural , gas)  engine  driven,  and one  engine  driven using only  meth-'
     ane.  To  provide the  required  air delivery,  only 4  of the 6  blowers  were
     required.  •
      a .       •       ^j--   r  _,;-..    -       -    -
     The proposal was  to use four 1750 RPM blowers which were  dual drive,  motor
     or  engine driven.  When digester  gas ' was  available, -the blower  would  be
     driven by  the  engines, and during other  times  by the  motors.  Three of  the"
     units were for  normal operation,  and one was standby* : A sketch showing  the
     before and after concepts  is shown in Figure 22.

Move Blower Building Closer  to  Aeration Basin      '                           '   '•..

     A blower building was to be  constructed to  provide  air to a new nitrifica-:
     tion basin.

     The  proposed  concept  recommended  moving the  blower  building to  allow  a
   '.  common wall with the  new nitrification basins.

Mechanical Aeration  to  Replace  Diffused Aeration in 1st and  2nd Stage Aeration

     The  original concept utilized a  diffused air  system  for  first  and second
      (nitrification)  biological  treatment.  The first  stage  was completely  mixedr
     and the second  stage  was plug-flow.

     The proposed concept recommended using mechanical  surface aerators  instead
     of  the  swing diffuser aerators.  Aerators were 'proposed to be dual  speed in
   \  the 1st stage  aeration  with one aerator per aeration basin. To  vary aeration
     capacity  in  the 2nd stage,  two dual speed aerators were recommended in each
     2nd stage  aeration basin.                  '-•:.-•

Lift Out Drop Pipes  Instead of  Swing Drop Pipes

     Aeration  basins were designed  "with "tee" walls  between the basins,  and the
     walkway between basins  was at  the  top  of  the  "tee".   The main  air header was
     attached  to the underside  of the tee, and was used  to  supply air  to basins
     on  each  side of the tee wall.  Between  the diffusers and the main air header.
     were  swivel  joint (top) and knee  jointed  (mid-point)  drop  pipes.

      The  proposal was to replace the  swivel joint drop  pipes  with lift  out drop
     pipes.  To check  diffusers,  the  lift out pipes  would  be  disconnected  at a

                                                               PROCESS EQUIPMENT
                                                               Aeration Systems


EACH AT 10.000 CFM

r.    .1
                                   ORIGINAL CONCEPT
     J   I
                                   PROPOSED CONCEPT
           Figure 22.  Use dual drives for blowers.

                                                                PROCESS EQUIPMENT
                                                                Aeration Systems
     quick  disconnect joint,  and  then lifted out.  A sketch of  the  original and
     proposed concepts  is  shown in Figure 23.                                   -

Constant  Speed/  Centrifugal Blowers  Instead of  Variable  Speed, Positive Dis-
placement Blowers

     The original design proposed rotary positive displacement blowers with vari-
     able speed drive motors to control  the volume  of  air  and power consumption
     for the  aeration system.

     The proposed alternate was to install centrifugal type blowers with constant
     speed  drives and use  valves  to throttle the  blower to vary  the air volume
     and power consumption.                                 ','-..

Use  Fixed Headers for Air  Supply Piping                                      :.

     The  original aeration concept was  a high efficiency  fine  bubble diffusion
     system,  using drop pipes from a main aeration  header near  the  top  of the

     The  proposed  concept  recommended  installing the  main  air  header  at the
     bottom of the tank, and attaching the  tube headers directly to the main air
     header.  This concept  eliminates the  need for  drop pipes and fitting, but it
     would  require the basin to be dewatered for diffuser maintenance.

Fine Bubble Diffusion in Lieu of Coarse Bubble Diffusion

     The original concept  proposed coarse bubble diffusion  as  the  oxygen transfer
     system for both  secondary and nitrification aeration.

     The proposed conqept  recommended  switching,.to fine bubble diffusion  because
     of the higher transfer efficiency and lower energy costs.

Replace Air Flow Tubes with Orifices

     The  original  concept used flow  tubes  for  measurement of  air  flow  to the
     aeration basins.

     The proposed concept  would use flange  mounted orifice plates to measure air
;     flow.        .      _'    ...'_-  '	  	    ..-'....-.

Mechanical  Surface Aerators in Place of Diffused Air System

     The   original  concept  used  conventional  diffused   air  system  utilizing
     blowers,  a  blower building,  air distribution  piping, and  baffle  walls in
     aeration basins.

     The proposed concept  would utilize mechanical surface  aerators which  provide
     a more   efficient  oxygen  transfer  and eliminate the  need  for  a   blower
     building, blowers, and baffle walls.

                                                               PROCESS EQUIPMENT
                                                               Aeration Systems
                            ORIGINAL CONCEPT
                                                     LIFT OUT DROP PIPE
Figure 23.   Replace swing drop pipes with  lift  out  drop pipes.

                                                                PROCESS EQUIPMENT
                                                                Aeration Systems
Use Single-Louver Control System

     In the original  concept,  louvers on  aeration tank blower inlets  were  indi-
     vidually controlled.   A louver would be  opened and closed with  the  corres-
     ponding blower, with the  amount of .opening regulated by  the  air  pressure in
     the inlet air channel.  As designed,  the  system could search for  the  correct
     louver opening, with  louvers fighting each other  unless  complicated  control
     systems were used.

     In the proposed  concept,  only one  control  system would  be used  to regulate
     the opening of all the louvers online.  This number of  louvers  open  would
     vary  from one  to  five louvers  depending  upon the number of  blowers  operat-
     ing, 'whether  screens  were clogged  by leaves  or snow,  or other  conditions.
     The  proposal  eliminates  four  sets  of  controls and  associated  hardware,
     software, and engineering.                                        ...:--

Use Common Air Piping  for Aeration

     The original concept  proposed one  air header pipe for each aeration basin.

     The proposed concept  recommended using one air  header  for each two tanks.A
     header  pipe' for  a single basin was  only required  when there  was an odd
     number of aeration basins.

Provide Single-stage Oxygen Plant
    I       '   • •    '•   : •      "    '••'•.           '       '•
     The  original concept  used a two-stage activated  sludge  system with carbon-
     aceous BOD  removal in the first stage "and nitrification  in the second stage.
     The plant utilized a  pure oxygen process for each stage.

     In  the proposed .concept  a   single-stage pure  oxygen  activated  sludge was
     used, thereby  eliminating the  intermediate  clarification step and providing
     a more compact plant.

Substitute Pressure Swing Adsorption for Cryogenic Oxygen System

     In  the original  concept pure oxygen  aeration was  used for  the  two   stage
     activated sludge system.  The  oxygen,was provided through cryogenic genera-
     tion which  has a limited turndown .capacity.          .  .  •

     In  the proposed concept pressure swing absorption oxygen generation was used
     thus  providing   substantial  turndown  capability to  meet   various  oxygen

 Substitute Anaerobic Filter for Periodic Peak Load Treatment

     In  the original concept the  treatment  plant was designed to  treat the  aver-
     age  flow with a  two-stage aerobic biological process. This  treatment  scheme
      included treating a seasonal wasteload from  a  food processing plant.

                                                                PROCESS EQUIPMENT
                                                                Aeration Systems
     In the  proposed concept the  food  processing plant waste  was pumped  to  the
     treatment plant  in  a separate pipeline. The proposed treatment  for  the  food
     processing  plant waste  would be  an  anaerobic filter,  which would  recover
     energy as methane gas and  reduce  the  BOD load to the plant.  The design  peak
     BOD  to  the main plant  would be  reduced  37.7% and  average loadings  19.5%
     using this  concept. The  existing trickling filters  would be renovated  for
     the  anaerobic  filters by  adding  covers,  improving underdrain structure  and
     providing radial collector pipes  from the  existing  turntable structure.

Change Aeration Basins to Complete Mix  Activated Sludge

     The  original  design included an  aeration  system  consisting of  long narrow
     basins  designed to  permit plug  flow,  step feed,  or contact  stabilization
     activated sludge.  The return activated  sludge  piping and inlet piping  were
     set-up to permit any and all  of the above  variations.

     It was recommended  that  the  basins be converted to complete  mix basins  in a
     single activated sludge  operating scheme.  The basins  for complete mix elimi-
     nated much of  the piping and  intermediate  walls associated with  the  original
     design. The proposed and original  concepts are  shown  schematically in Figure

Eliminate Spray System in Aeration Tanks

     The  original  design concept  included froth control using spray headers  and
     nozzles around the  aeration basins.

     The proposed concept recognized  that  froth was  not  a  problem in  the  existing
     plant and  that it  would not be  a problem  in  the  new plant, except during
     plant startup. It  was recommended to eliminate the froth control system in
     order to lower construction  cost.

Submerged Turbines  Instead of Diffused Air

     In  the  original design,  aeration   was  to be provided  using  centrifugal

     It was  recommended  that submerged turbines be  installed  in the  basins  and
     new  smaller centrifugal  blowers,  with a lower operating cost, be used.

Remove Covering from  Biofilters

     The  initial design  concept   included two  biofilters  covered with  geodesic

     It was proposed  to  use  the same  filters and remove  the covers.

Replace Mixed Liquor  Channel  with Pipe

     Originally, the  mixed liquor from the aeration  basin  discharged to a channel
     which passed between the secondary clarifiers  and was.used to distribute the


                                                                 PROCESS  EQUIPMENT
                                                                 Aeration Systems

           '  I    FLOW CONTROL GATES TYP) f~*" SECTION
                         PLUG FLOW REACTOR
                           •STEP FEED CHANNEL
                                                             MIXED LIQUOR
                                                             COLLECTION CHANNEL
                                                              TO SECONDARY
                  ORIGINAL CONCEPT .



-T-*- - .
• • -rz^:. ,
• . * '
                                                       .•  *.
                                                  FIXED DIFFUSERS

                              TO SECONDARY
         CLARIFIER (TYP)
                                                      SURFACE AERATORS
                             PIPE (TYP)'

                                          PRIMARY EFFLUENT
                                          DIFFUSER PIPES
                             PROPOSED CONCEPT
                Figure 24.   Use  complete mix activated sludge.

                                                                PROCESS EQUIPMENT
                                                                Aeration Systems
     The proposed system was  to  replace the MLSS channel with pipe  and distribu-
     tion boxes  at  each pair  of secondary clarifiers.  This system  required  the
     construction of  multiple distribution  boxes and had  reduced access  to  the
     pipeline.  However, the  recommended  system  was less  costly  and  provided
     better scum control  since no scum  formation would  occur until  the  effluent
     reached the distribution  box.  At the distribution box  the  scum would settle
     much better  than  in  a reinforced  concrete channel  as originally  planned.
     Figure 25 shows sketches of the  original  and proposed  ideas.

Use One 70 ton Cold Box in Place of 2-35 Ton Boxes

     The initial design consisted of  a cryogenic oxygen production plant  consist-
     ing of two 35 ton  cold boxes,  two 100% compressors, and two  70% compressors
     used as support facilities.

     It is recommended that a single  70  ton cold box with  required support facil-
     ities be used in place of the two 35 ton  boxes.  The required  support facili-
     ties then included a single 100% compressor and a single 70%  compressor.

Use Oxidation Ditch Instead of Extended  Aeration

     The original design  concept included extended  aeration with submerged  tur-
     bine aerators.    The  original  concept also provided  aerobic   digestion  of

     To provide simplier operation and more reliable treatment,  the  proposed  con-
     cept suggested  using an  oxidation ditch with  brush  aeration. This  system
     required no primary treatment and no aerobic digestion.

Use Activated Bio-Filter (ABF) Process Instead of Extended  Aeration

     The original design  was  an extended aeration system with  submerged turbine

     The proposed  concept  recommended  using  the ABF process  with  the biofilter
     followed  by  short aeration basin  using  mechanical aerators.   The  proposed
     system could  tolerate shock  loads better, was more  energy efficient,  and
     eliminated equalization storage.

Centralize Air Supply System

     The  original  design  concept included  blowers  located at three different
     locations with a total blower capacity of 2,000  CFM.

     The proposed concept suggested  centralizing the air supply system at a  sec-
     ondary control building.  The proposed design  increased the  blower  capacity
     to 2,500 CFM, but eliminated two blowers,  and reduced  housing requirements.

                                                                PROCESS EQUIPMENT
                                                                Aeration Systems
Aeration Basins
Clarifiers (typ)
 Aeration Basins
                    60" pipe-j
                                          Distribution weirs
                                                                   Clarifiers (typ)
                                                                   F i na I
                                                                   Clarifiers (typ)

                                                                 '.  Clarifiers (typ)
           Figure 25.  Replace  mixed liquor channel with pipe.

                                                               PROCESS EQUIPMENT
                                                               Aeration Systems
Use Aluminum Covers Rather Than Concrete Over Aeration Basins

     The original design  of  the  aeration basins in  a pure oxygen plant included
     concrete slab covers.

     The proposal recommended using aluminum covers in place of concrete slabs.

                                                                PROCESS EQUIPMENT
DISINFECTION.    " '.'.    ;._'.'"......'.'           .                                    •.'....

Use Ozone Instead of Chlorine

     The plant utilized high rate  trickling filters for carbonaceous BOD removal,
     and .pure  oxygen activated sludge  for nitrification . On-site  oxygen genera-
     tion facilities  were  planned. Chlorine with dechlorination  was required for
     effluent disinfection.

     The proposed concept  recommended -. using  ozoriation instead  of chlorination ,
     since pure oxygen generation  facilities were already planned for the site.

Reduce Chlorine Contact Basin  Size

     Plant  effluent was disposed  to a  deep-well system  near  the  plant  site. A
     chlorine  contact basin was used to meet disinfection  requirements prior to
     flow diversion  to the deep-well system.

     Use  of the  deep-well system capacity to provide  a  portion  of  the overall
     chlorine  contact time, similar to  an outfall, was  proposed. This proposal
     resulted  in  a  40% reduction in the size of the chlorine contact chamber.
Use Tank Trailer for SO2 and
     The  original  concept used  large  cylinders for  SO2 and  C19 storage  in  a

     The  proposed concept recommended  using tank trailers with a capacity of  18
     tons each  to deliver  and  store  SO2  and C12ซ  The required building  size
     would be reduced by 2300 square feet.

 Revise Location of Chemical Injection Points

     The  original concept was  for  chlorine contact tanks which provided  approxi-
     mately 15 minutes detention time from the tank inlet at maximum  flow.

     The  proposed concept was  to move  the point of chlorine application  from the
     inlet of the  chlorine  contact tank  upstream and also to  move the point  of
     the  sulfur dioxide  application from  the  outlet of  the  chlorine tank  down-
      stream. The  lengths  of  influent conduit  and effluent conduit would  provide
     additional contact  time  for  the  chlorine,.  .The additional  volume in  these
     conduits permitted shortening of  the contact tanks, and reducing  the number
     of concrete piles, excavation  and  backfill.

 Reduce the Number of Chlorine Cylinders

     The  original design concept  included  room for  two operational  cylinders,
     plus a  storage  capacity for fifteen  chlorine  cylinders.  A bridge  crane was
     provided to move  the  cylinders .  The chlorine system was designed  to provide
      disinfection for the entire plant  flow.

                                                                PROCESS EQUIPMENT
     The proposed concept recognized  that  it  was  not necessary to provide  disin-
     fection for the entire plant flow  and that only the  portion of flow used for
     reclamation  needed be  chlorinated.  The proposal   recommended  cutting  the
     storage area in half to provide  room  for five cylinders  plus an area for the
     two operational cylinders. Also, it was  recommended  that the bridge crane be
     replaced with a monorail crane.

Reduce Chlorine Contact Chamber Size

     In  the  original  design,  the  chlorine contact  tank and three  chlorinators
     were sized for disinfecting the  entire plant flow. A portion of the flow was
     to be used as reclaimed water.

     In the proposed  recommendation,  the chlorinators would  continue  to be sized
     for all of the plant flow, but the size of  the  chlorine contact  tanks would
     be reduced so that only a portion  of  the effluent would  enter. The reclaimed
     water would attain  an  adequate contact  time while  in plug  flow  through the
     pipeline to its reclamation use.

Eliminate Chlorine Contact Tank Bypass

     The treatment facilities were  to be constructed in two phases.  In the orig-
     inal phase,  a  chlorine contact  basin bypass line was  to be  constructed in
     order  to  facilitate  the additional  chlorine  contact  basins  construction.
     The chlorine contact basin drains  connected  to the bypass line.

     It was recommended  to  eliminate the bypass  under the  chlorine contact tank.
     The proposed  change would result  in  some   loss  of  flexibility  during  con-
     struction. However,  the  effluent  flumes would permit operation  of the  con-
     tact basins  while the new  basins are  being constructed.   The  entire  flow
     would be diverted to  one-half of  the chlorine contact  facilities  for short
     periods when the  new basins were being connected into the flumes.

Ton Containers Instead of 150 Ib Containers for Cl^ and SO? Containers

     The original design  called for  chlorine and sulfur  dioxide  to be dispensed
     from 150 Ib cylinders with tank-mount type gas feeders.

     The proposed concept recommended dispensing  chlorine and sulfur dioxide from
     1-ton cylinders  with  the same  type  of  feeders.   The proposed system would
     provide  less frequent  changeovers and more  reliability  due to  increased
     storage capability.

Replace SOp Mechanical Mixer with a Hydraulic Mixer

     The initial design mixed SOg with  plant effluent by  mechanical jet mixer.

     The proposed concept  suggeted mixing  the   SC>2  by   hydraulic  mixing  at the
     chlorine contact  basin effluent  weir.

                                                                PROCESS EQUIPMENT
Simplify Chlorine Scrubbing System

     The initial design included  a chlorine  scrubbing system to collect and scrub
     chlorine gas in the event of a chlorine cylinder break.

     Realizing the high expense  of  this system, the VE  team recommended elimina-
     ting  spent  caustic  storage, redundancy in pumps and  fans,  and all  but the
     most  basic  controls.  The  proposed  system layout  consisted of a scrubber,
     pump, a  3500  gallon  sump tank, and  a chlorine detection  system to automat-
     ically start the  system. The sump tank  would be filled with caustic solution
     from  55  gallon  drums and diluted with water  to  a 10% concentration.   When
     the  scrubber system  was activated,  the  contents of the  system would  be
     pumped through the scrubber  and then back into the sump. Solution would con-
   -  tinuously  recirculate until the  emergency passed and  the scrubber  shuts
     down. The  sump  could then be drained and refilled as needed after emergen-
     cies  to  supply fresh  caustic.             ,

Reduce Dechlorination  Tank Size

     The  original concept used  open   channel  mixing  of   sulfur  dioxide, in the
     dechlorination step,  followed by  5 minutes detention  in a baffled channel.

     In  the  proposed concept, a  flash mixer for instantaneous contact was  used,
     followed by a contact basin with  about one-half the original contact time.

                                                                PROCESS EQUIPMENT

 Package Steel Filters Replacing Reinforced Concrete Structures

      Filters for  tertiary  filtration  were  to be  constructed  using reinforced
      concrete tanks.                                                    "

      Package steel tanks  were  proposed as  a substitute for  the reinforced con-
      crete structures,  with the  filters  constructed  and  shipped  for immediate
      installation.  Concrete channels were  to be used  for  influent distribution,
      while filter effluent  and  overflow connections to the  filter were  by means
      of header  pipes.

 Use Surface Washers in Place of Air Scour

      The original  concept  proposes  to  use  blowers  to -provide  air scour  for
      supplemental agitation during filter backwash. Blower's were provided in each
      filter gallery.

      The proposed concept would use a surface  wash  system  which would consist of
      turbine pumps  with two surface arm washers per filter located just above the
      media.  The nozzles on  the  wash  arms will  both rotate the  arms  and  agitate
      the media.

 Use One Backwash  Rate  Controller in Place of Two

      The original concept used one backwash  pump  in each  of  two pipe galleries,
      and an interconnection pipe between galleries.  The pump arrangement required
      two 24-inch  backwash  rate  of flow  controllers.

      The proposed concept recommended locating  both backwash  pumps in one filter
      gallery and eliminate one  backwash rate  flow  controller.  Motor  controls
      would  be all located  in the same area.

Eliminate Effluent  Rate Controllers on  Declining Rate Filters

      The original concept  proposed declining rate  filters  for filtration.  It also
      included rate  of  flow controllers  on  the effluent from the filters.

      The proposed concept  recommended  eliminating the  rate  of  flow  controllers
     because  the declining rate  filter concept  assumes   a  declining rate  flow
     through  each  filter  as the  head  loss  increases  and a  splitting  of  flow
     between  the  filters based  on  the  varying head  losses.  In  order  to  control
      the maximum rate  of flow through the  filter it  was  proposed to calibrate  the
     rate  of the  flow  through  the effluent butterfly  valve  by using  orifice
     plates or a propeller meter.

Replace Hydraulic Valve  Operation  System with Pneumatic  System

     The original concept  proposed to  use a hydraulic valve operation  system  for
     filter process valves.

                                                               PROCESS  EQUIPMENT
     The  proposed concept  would  replace  the  hydraulic  system  with pneumatic
     valves for all process'valves, and delete the fluid return pipe  system.

Reduce Gullet Width by One Foot                         ,

     The original concept proposed using  5  foot wide  gullets  in  the filters.

     The proposed concept would reduce'the. overall  structure length  by  reducing
     the gullet width to 4  foot  (without  affecting the  backwash  operation).

                                                                PROCESS EQUIPMENT
                                                                Post Aeration

Use Turbine Aerators

     An existing chlorine  contact chamber was to be converted  to  a post-aeration
     basin/ with diffused aeration being used to  supply  the air  and  turbulence
     required for reaeration.

     Submerged  turbine aerators  were proposed  to  provide  the  required air  and

Cascade Aeration Replacing Pure Oxygen

     Pure  oxygen  was  to  be stored  on-site  and  fed after  the chlorine  contact
     chamber to add dissolved oxygen  to  the plant effluent.

     Little head loss  was  available  for  the  plant  effluent, but  sufficient  head
     loss was available for a cascade type aeration chamber  immediately after the
     chlorine chamber.

                                                                PROCESS EQUIPMENT
                                                                Chemical Feed  •
CHEMICAL FEED                     '  -J         '  "

Consolidate Lime Feed Systems

     A 4 mgd  facility  was being expanded  by  14  mgd, but. because  of site limita-
     tions  there  would be  two distinct plants  on  the  site.   Lime feed systems
     were proposed  to"' control  pH prior to nitrification,  and  separate lime stor-
     age and  feed systems were proposed for  the "old" plant and the "new" plant.

     The proposed concept was  to utilize the lime storage and feed  facilities for
     the plant  expansion as a  centralized lime feed system for  the entire site,
     and to convey slaked  lime from the  cejrbral  facilities  by a  series of open
     channel  troughs to  the "old."                .       r  .

Use Larger  and  Fewer Lime Feeders         ;   .,/,,'-,;-. ...           *        ......

     Eight  lime storage  silos, each with 3750 cubic feet of storage capacity were
     in the original 'design. A separate lime feeder was utilized for each of the
     silos.            ,..-•...••.      •       •.      .               ....''

     It was proposed that the  silo capacities  be increased from 3750 cubic feet
     to 5000  cubic  feet  each,  and that the number of silos be decreased  from 8_  to

Bulk Storage  and  Handling for Chlorineand Sulfur Dioxide

     In  the  original  design,  the  disinfection  system included  the use  of ton
     cylinders  for chlorine and sulfur dioxide.

     Recognizing  the possible  unreliability  of  the  original concept  the proposed
     concept  recommended using a safer more economical bulk storage  and handling
     of these chemicals  rather than ton cylinders.

Eliminate  Lime Slurry Feeders                   .  ,  • -.

     ~From  a lime  slaker, lime  slurry was  conveyed  to a mix tank and  then  to  four
      smaller  tanks. Two dual head  metering  pumps were  used to feed from the  four
      smaller tanks to four application" points.

      One  large lime slurry tank complete with mixer was proposed  to replace  the
      original  system of  the mix tank and the four  individual tanks.  A circula-
      tion  loop would  be set up  and fed  by  recirculation pump.   At each of  the
      lime  discharge points, control valves  would be used  to  control the  rate  of
      lime  addition.  The recirculation loop, recirculation pump,  and the  control
      valves-replace the metering pumps.

                                                               PROCESS EQUIPMENT
                                                               Chemical Feed
Purchase Carbon Under a Separate Contract

     The original design obtained carbon for  charging  the  carbon  adsorption   sys-
     tem under construction contract.

     The proposed  concept would  let  a separate  contact  under  separate bid  for
     purchase of carbon.

                                                                PROCESS EQUIPMENT
                                                                Sludge Collection.
SLUDGE COLLECTION                   -         -S^-:.--;

Replace Chain Drag Sludge Collector with  a  Traveling Bridge Sludge Collector

     Twelve clarifiers  were  utilized for removal of  1st  stage  biological sludge,
     each clarifier  being 15' wide.  Sludge collection was by chain  drag units,
     one for each 12 basins,  to hoppers at  the  influent end of the. basins.  Sepa-
     rate air lift pumps were used for sludge removal from each basin.

     The proposal was  for elimination of the chain  drag units and the  air lift
     units, and  substitution of  a traveling-bridge type  sludge collector.  Addi-
     tionally, the number of clarifiers was to  be reduced from 12 basins 15' wide
     to 6  basins 30' wide.   The  traveling-bridge  mechanism which was  proposed
     would be  adapted  to operate on  two of  the  30'  wide clarifiers  at  the same
     time.  Submerged perforated pipe weirs were recommended for effluent collec-
     tion instead'of the original "v"-notch weir and trough system.

Use Non-Metallic Chains in Primary Clarifiers

     The original concept utilized cast  iron chains and redwood flights.

     The proposed  concept recommended that non-metallic chains  be utilized as a
     substitute  for  the cast-iron chains.

                                                                PROCESS  EQUIPMENT
                                                                Sludge Thickening

Reduce Number of Gravity Thickeners

     Four gravity sludge  thickeners,  each 45 feet diameter  with a 10 foot  side-
     water depth were used in the original design concept.

     Reduction  of  the number of  units from  four  to two was  proposed,  with  the
     diameter  of the  thickeners  increasing  from 45  foot  to  60  foot diameter
     thickeners being used in the proposal.

Rearrange Dissolved Air Flotation Units

     Two dissolved  flotation thickeners  were  arranged  with  a  14'  wide  gallery
     located between the  thickeners.  This gallery contained all  the  drive units,
     thickened sludge pumps, and a thickened  sludge  storage  tank.

     Elimination  of the  gallery between the  units and  use  of a  common  wall
     between the  units  was proposed.  A much smaller gallery  was constructed  at
     one end of  the units  to  contain  the  pumping equipment, and  the  sludge
     storage tank was eliminated. The  proposal  substantially reduced  the required
     building floor area, as well as the  quantity of required  piping.

Change Bottom Slope of Primary Clarifier

     Originally, the primary clarifier was intended  to provide both clarification
     and sludge thickening to  approximately a 5% solids  content. To  accomplish
     this degree  of thickening a dual-slope bottom was  used  for the  clarifier,
     and polymer was planned  to be  used in  subsequent sludge  treatment  if  5%
     solids could not be  obtained in the  clarifier.

     The proposed  concept recommended modification  of  the  clarifier bottom to a
     constant slope bottom and  the addition  of a separate gravity sludge thick-
     ener. The proposal was based upon the anticipated advantages of  better over-
     all clarifier  operation,  and a greater  likelihood  of  achieving a  5% solids
     concentration  in the  thickener  than in the clarifier.  A sludge  thickener
     should more  consistently produce  a  5%  solids  concentration sludge,  thereby
     reducing polymer costs.

Use Gravity Thickeners For All Sludge

     A pure oxygen  activated  sludge  plant was  designed to use gravity  thickening
     for the primary sludge and dissolved air flotation  (DAF)  for the pure oxygen
     secondary  sludge.  The anticipated concentration for  the  DAF product was  4%
     solids. Both the gravity  thickeners and  the DAF  units  were  enclosed  in a

     The proposed concept  recommended using  gravity thickeners for  thickening
     both the primary and secondary  sludge.   Although gravity thickening  of bio-
     logical  secondary  sludge  is  difficult,  the  proposal  was based  ' upon  the

                                                                PROCESS EQUIPMENT
                                                                Sludge Thickening
     experienced ability  of pure oxygen  activated sludge  to  be thickened  to  4%
     using gravity thickeners. The building  included  in the original proposal was

Convert Gravity Thickeners  to Air Flotation  Thickeners            ,',.",'

     The  original  concept  proposed  to  construct  two  air flotation  thickening
     tanks with  a  total of  1600  square  feet of  area  for .concentration  of  waste
     activated sludge.

     In the proposed concept two  of  the existing gravity thickeners, with a tptal
     surface area of. 2500 square  feet,  would be converted  and  used  as  air flota-
     tion thickeners.

Thickening of Waste Activated Sludge (with chlorine addition)

     The  original  concept  proposed  use  of  air flotation  to  concentrate  waste
     activated sludge.                                          .           ,

     In the  proposed concept existing 40-foot  diameter gravity  thickeners  would
     be used to thicken the waste  activated sludge.  Chlorine  was  to be  used to
     aid  in  the  thickening process.  It was  estimated  that  approximately 100 rag/L
     of chlorine would  be required  for the thickening process.

Eliminate Pump Suction  Control Valves and Magnetic Flow' Meters          '

     The  original design  balanced the sludge withdrawal rates from each clarifier
     by utilizing butterfly valves,  and magnetic flow meters with motor operators
     for  the butterfly  valves.  The  sludge return rate  to the  aeration tank would
     be controlled by variable speed return  activated sludge pumps.

     The  proposed  concept  would  use an arrangement  of telescoping  valves  and a
     headbox arrangement  at each set of  clarifiers.  By adjusting, all telescoping
     valves  to  the  same elevation  equal  quantities of  sludge  would be withdrawn
     by hydraulic displacement  from each  clarifier. This rate would be adjustable
     by raising  and  lowering the  telescoping valves.  Each telescoping valve would
     be  located in a  separate compartment  in  the headbox  and  discharge  over a
     V-notch weir so   that  the  flow balance could  be  checked and  adjusted as
     required.  Figure 26  shows  sketches of the  original and proposed concepts.

Consolidate  All  Thickening at One Location     :        ;
                     " - •                             "''",-            • f     -
     The  design  of the  treatment facilities  included a wastewater treatment plant
    'at one  site and  a  separate solids handling facility at another site. In the
     original  design, the waste  activated sludge was  thickened in ?a dissolved air
     flotation  unit  on-site at  the wastewater  treatment plant before pumping to
     the  solids  handling plant.  A 3-1/2%  solids mixture of primary and thickened
     waste activated  sludge was  to  be pumped to the solids handling plant.

.  •   The  proposed concept  recommended  no  thickening  at  the  wastewater plant.
     Instead,  a 1.8% solids mixture of  primary and waste  activated sludge would
     be pumped directly to  the solids handling  plant for thickening. This  system

                 1 ' '  - ":\- -  •  -         .75       ' •  -'  -    .:••...   .    •    /

                                                             PROCESS EQUIPMENT
                                                             Sludge Thickening
                     S"  -
            5H3      SKB



                                                                     RAS PUMPS
                                RAS PUMPS
                             ORIGINAL CONCEPT
                                                      V-NOTCH WEIR (TYP)
                          TELESCOPING VALVE
                                 RAS PUMPS
                                                                    RAS PUMPS
                            PROPOSED CONCEPT
     Figure  26.   Replace control valves with telescoping  valves.

                                                               PROCESS  EQUIPMENT
                                                               'Sludge Thickening
     eliminated  the  need  for  thickening at  the wastewater  treatment plant  and
     consolidated all thickening at one single location.

Reduce Dissolved Air Flotation Size

     In the  original design,  a  single 700 sq  ft dissolved  air flotation  (DAF)
     unit was  provided  at the facility.  The  unit was  sized  to accommodate  peak
     flows of 2.3 times the average daily flows.

     The proposed concept  recommended reducing the  size  of the DAF  thickener to
     300 sq ft and providing a polymer feed system.  The polymer feed system would
     be used only during peak  flow conditions which were estimated  to occur only
     about 5% of the time.

Eliminate Gravity Thickeners

     The original concept  provided gravity sludge thickeners  for  thickening pri-
     mary  sludge.  Included  with the  thickeners  was  a thickened sludge  holding
     tank and a pumping station.

     The  proposed concept  eliminated the  gravity thickeners  and  increased  the
     capacity  of the vacuum filters  and  also increased  the  size  of  the  mix and
     holding tanks associated  with the vacuum filters.

                                                               PROCESS  EQUIPMENT
                                                               Sludge Dewatering

Eliminate Covers from Sand Drying Beds

     The original design concept included sand drying beds with  covers.

     The proposed concept  suggested using the sand drying beds, but  deleting the
     covers and thereby providing easier  access  to  the  beds.  Drying, time  would be
     decreased during summer months but would increase  during poor  weather.

Add Heat Treatment for Sludge Dewatering

     In the  original concept, sludges from the  primary and  biological processes
     required  chemicals  in  the  dewatering  process.   The  dewatered  sludge  was
     hauled to a remote incinerator.

     In the  proposed concept, heat treatment would  be added  to  the  dewatering
     process,  thus   increasing the  percent  solids  and  decreasing  the amount  of
     sludge that needed to be hauled  to the remote  incinerator.

Substitute Filter Presses  for Vacuum  Filters Prior  to  Incineration

     In the  original concept  for the sludge handling system, vacuum filters were
     used to dewater the  sludge  prior to multiple  hearth incineration. The  orig-
     inal heat balance calculations  used  20 to 25% moisture  for  vacuum  filter
     dewatered sludge.

     In the  proposed concept,  vacuum filters would be  replaced  by  filter presses
     with a planned  capability of producing 40%  solids  filter cake. The increased
     solids  concentration  would  reduce or eliminate supplemental fuel required by
     the incinerator.

Eliminate Waste Activated  Sludge Centrifuges

     In  the  original  concept centrifuges  were  used  to thicken waste  activated
     sludge  prior to aerobic  digestion.  The system employed one unit with another
     standby centrifuge for  either  this operation or  for  thickening  anaerobic
     primary sludge  digested.

     In the  proposed concept  no  centrifuges were provided and the waste activated
     sludge  was  aerobically  digested directly  without thickening.  The  existing
     aerobic digestion  facilities provided  6-1/2 days  digestion under these oper-
     ating conditions.

Use Conveyor Belt for Dewatered  Sludge in Place  of Pumps

     The original concept  indicated that dewatered sludge cake from a belt filter
     press was to  be pumped to  a truck  loading  facilities  and  then  to  be hauled
     to a landfill.  The type  of  pump was  unspecified.

                                                                PROCESS EQUIPMENT
                                                                Sludge Dewatering
     Since the 25% to 35% moisture  content of "the dewatered  sludge  from the belt
     filter press  would be very  difficult to pump,  the proposed concept  recom-
     mended that the dewatered sludge be transported by a conveyor belt.

Use Waste Pickle Liquor in Lieu of Ferric  Chloride

     The original  concept was to use  a ferric chloride  solution  for one  of  the
     chemical conditioning agents.

     The proposed  concept would  be to obtain free  waste pickle liquor  from  a
     local steel mill.

Use Belt Filter Press with Polymer Conditioning in Lieu of Plate and Frame  .

     The original  concept  utilized  a plate and frame filter  with  ferric chloride
     for sludge dewatering.       -

     The proposed  concept used a  belt filter  press with polymer conditioning.  The
     proposed  concept •  simplifies operation  and  provides  greater  visibility  of
     operating conditions.

Use Precast Concrete Walls for Sludge Drying  Beds

     The original  concept used sand drying  beds.  Walls  for the various  sludge
     drying beds were to be constructed of cast-in-place reinforced  concrete.

     The proposal  was  to  use precast  concrete panels  as  a  replacement  for  the
     original walls.  The  precast  panels would be maintained in position  by pre-
     cast supports. A sketch  of the  proposed-concept is shown in. Figure 27.

Design Sludge Dry  Beds  for Mechanical Sludge  Removal

     Sludge disposal  by liquid application on  a  golf  course was planned  as  the
     primary method of  disposal.  When this primary method was seasonally unavail-
     able, on-site sand drying beds  were  to be utilized.  Because  the sand drying
     beds were to  be  used  only periodically,  they were  designed for  manual sludge
     removal. The  original design was  for  drain tile covered  by a sand and gravel
     blanket.                 -. •   -   -~ '". -              " - :     •       ^

     Beds  suitable for sludge  removal by  a .front end loader  were  proposed.
     Asphalt  was  proposed over a base course,  and  the  asphalt sloped to  a  six
     inch concrete drain tile running  down the   center  of the-  bed.  The proposed
     design would  allow use of mechanical  equipment. Sketches of the original and
     proposed concepts  are shown  in  Figure 28.

Substitute Belt Filters for Vacuum Filters

     Sludge dewatering  was to be  performed using  vacuum filters, with sludge con-
     ditioning by  lime  and ferric chloride.                 .

     Replacement  of  the planned  vacuum filters  with belt filters  was proposed.
     The  conditioning  chemicals  would also  be  switched, from lime  and  ferric
     chloride to polymer.

                                               PROCESS EQUIPMENT
                                               Sludge Dewatering
                  POURED CONCRETE
               ORIGINAL CONCEPT
                  PRECAST PANEL
               PROPOSED CONCEPT
Figure 27.  Use precast concrete walHs.

                                                               PROCESS EQUIPMENT
                                                               'Sludge Dewatering
                         ORIGINAL CONCEPT
3" THICK. 1/4'TO 1/2* GRAVEL


                         PROPOSED CONCEPT
Figure 28.  Design sludge drying beds for mechanical equipment

                                                            PROCESS  EQUIPMENT
                                                            Sludge Stabilization

Replace Anaerobic Digestion with Stabilization Lagoons

     Originally,  digestion and thickening was planned  for sludge  stabilization
     prior to placing  it in a storage  lagoon.  Ultimate sludge disposal  from the
     storage lagoon was  by hauling to landfill.

     The proposed concept  recommended deleting the  digestion and thickening  sys-
     tems and utilizing  a series  of anaerobic/aerobic ponds  to  store  and stabil-
     IzlTthe  sludge.  As the ponds were filled with  sludge,  they would  be taken
     out of service  and  the sludge allowed  to  dewater  and dry.  The, sludge could
     then be loaded and  hauled to  a landfill site. The  lagoon  sludge	stabiliza-
     tion  system  would  be  used   to   provide  the  detention  time  required  to
     'stabilize  the  waste sludges  from  the plant as  well  as to  provide  adequate
     surface oxygen in the ponds to minimize odors.

Replace Gas Mixing System with Mechanical Mixers

     Originally,  the  anaerobic digesters  were provided with a  gas  mixing system
     which did  not provide complete mixing.

     It was  recommended that a mechanical mixing system be used  in place of the
     gas mixing system.  The proposed  system provided better mixing for  the same
     horsepower  input,  required  less  maintenance,  consumed   less energy,  and
     required  less building space than the  original  design. A  schematic of the
     original and proposed mixing  systems are shown in Figure 29.

Reduce Digester Size

      In  the  original  design, two  anaerobic  digesters were sized to provide  a 27^
      day  detention time,  which would  give  a 13-1/2  day  detention  time  with one
      digester out of  service.

      The  proposed concept recommended  reducing the size of the digesters  to pro-
      vide a  14-day detention  time,  which  corresponded  to  0.11 Ib  VS/CF. This
      loading was considered well  within  the range of  accepted time and  loadings
      for a high rate digestion. Backup sludge holding capability was available  at
      the  plant if one of the digesters  had  to be taken  out  of service.

 Delete Waste Activated  Sludge Digestion and Dewater Directly

      The original design  combined primary sludge with waste activated sludge  for
      treatment in anaerobic digesters.  The  combined  anaerobic  digested  sludge  was
      then dewatered on  belt presses.

      It was recommended that  the  waste activated sludge be  dewatered on the belt
      presses prior to  digestion.  This  proposal  reduced the required size of  the
      anaerobic digesters.

                                                             PROCESS  EQUIPMENT
                                                             Sludge Sta]5iiization~
                                                FLOATING OR FIXED COVER
                         ORIGINAL CONCEPT
                      GEAR BOX
                      TURBINE BLADE
                         PROPOSED CONCEPT
          Figure 29,   Mechanical mixing in anaerobic digesters.

                                                             PROCESS EQUIPMENT
                                                             Sludge Stabilization
Provide Aerobic Digestion for Secondary  Sludge

     The original design concept  for  sludge  stabilization 'involved thickening the
     waste  activated sludge from the secondary  settling basin and  then  anaero-
     bically  digesting it.

     The proposed  concept  recommended using  anaerobic digestion  for  the  primary
     sludge and  providing  aerobic digestion  for stabilizing the  waste  activated

Movable Gas Holder Cover to  Replace Fixed Cover on Primary Digester

     The original  design included  a fixed cover on  the  primary  digester  and  a
     high pressure  (65 psi)  sludge  gas storage  tank with three gas compressors.

     The proposed  concept  recommended eliminating the gas storage tank  and pro-
     viding a movable cover on  the primary  digester. Gas required  for  digester
     heating  and for use  in the  digester control  buildings would  be  furnished
     from digester storage.

Insulate Anaerobic Digester  Covers

     Anaerobic digesters were  designed with  steel plate dome covers.

     Addition of a 2-inch  sprayed-on foam layer  was proposed on top  of  the steel
     cover  to provide further  insulation to  the digesters.

Digester Heating with Hydrogen Gas

     The plant  utilized on-site  hypochlorite generation  to  produce  hypochlorite
     for effluent  disinfection.  Hydrogen gas which  was  produced during  the hypo-
     chlorite generation was planned  to  be wasted.

     Use of the hydrogen gas  to  replace digester  gas used  for digester heating
     was proposed.  Hydrogen gas  would  be used  along  with the  digester  gas  in  a
     boiler to heat  hot  water.  The digester  gas  which was saved by the  substitu-
     tion  could  then be  used  in  an  engine  generator  to  generate  electrical
     power.                                                :

Earth Berms Around Anaerobic Digesters

     Anaerobic digesters were  designed with  a  25 foot wall  height,  10 feet below
     ground and  15 feet  above  ground. 16-inch thick concrete walls were used with
     no other form of insulation.          ...   . -  .	
                                         ''•'-. f "'••''  ' *'f M '••' ป          .,. , '•':''ป'   * •

     Use of earth  berms  to insulate  the  digesters  was proposed to lower.. digester
     heating  requirements  and  provide a  more aesthetically pleasing plant site.

Eliminate Anaerobic  Digester Supernatant Tank

     The  original concept  was to  construct a holding  tank to  store  anaerobic
     digester supernatant and to feed  it back  to  the headworks  at  a controlled

                                         84                           '

                                                            PROCESS  EQUIPMENT
                                                            Sludge Stabilization
     In the proposed  concept the supernatant  holding tank was deleted,  assuming
     that the secondary digester could be considered  as a  holding  tank.

Eliminate Aerobic Digester and Use Existing Anaerobic Digesters

     In  the original  concept,  centrifuges  were  to  be   used  to  thicken waste
     activated sludge. Existing primary clarifiers and aeration basins  were to  be
     converted  to  aerobic digesters  for digestion  of the  centrifuge  thickened
     WAS. Primary  sludge  was to be anaerobically  digested in existing  anaerobic

     In  the proposed  concept  the same  centrifuge  thickening  scheme  was to  be
     retained, but the existing anaerobic digestion  capacity  was  to be  used  for
     both the primary  sludge and the centrifuge  thickened  WAS.

Substitute Boilers in  Place of Supplemental Solar Panels

     The original concept utilized a solar panel hot water system  to furnish  sup-
     plemental heat to the digesters.

     The  proposed concept  would provide  more  reliable   conventional  oil fired
     boilers and completely eliminate the solar  panels.

Include Conical Portion of Anaerobic Digester  in Effective Volume

     Anaerobic digesters were  105-feet in diameter and had a bottom slope of  1:1.
     Detention  time in  the anaerobic  digesters was calculated  using  only  the
     cylindrical portion of the digester, and  did not count  the conical portion.

     The proposed  concept  recommended that the  conical portion be  included  as a
     usable  portion of the  digester capacity and  in  calculating  the  detention
     time of sludge in the digester.  This would,allow the  digester diameter to be
     reduced from  105  feet to  85  feet.

Substitute Mechanical  Aeration for Diffused Aeration in Aerobic Digesters

     A  activated sludge plant was to  aerobically  digest thickened primary  and
     waste  activated sludge. The  original concept-  was to  use diffused aeration to
     supply air to the aerobic digesters.

     The  proposal  was to  utilize surface  mechanical  aerators  to replace  the
     diffused aeration system.

Reduce Number of Digesters and Use Floating Covers

     The  plant  was to be designed using  three anaerobic   digesters,  each 90  feet
     in  diameter  and  24 feet SWD. Two feet of freeboard   was provided,  and fixed
     concrete covers  supported on concrete were used on each  digester.  Gas stor-
     age  at 50  psig  was  provided  in  a  gas  storage  Sphere  for  1  day of  gas
     production at 50  psig.

                                                             PROCESS  EQUIPMENT
                                                             Sludge Stabilization
     Reduction of  the number of  digesters  from 3 to 2  was proposed,  along  with
     elimination  of  the  gas  storage  sphere.  Gas  storage  was  proposed  to  be
     accomplished  by  the  addition of steel  floating gas holding covers  for  both
     digesters. The new digesters  would be  110  feet in diameter and  have 24  feet
     of SWD.

Eliminate Cranes from Anaerobic Digester Roofs

     Three 95  foot diameter anaerobic  digestors  with fixed  concrete  covers  were
     utilized for  sludge  stabilization.  Heating of  the  digesters  was  accomplished
     using vertical internal heat  exchangers placed into  the digesters  through
     the roof. Each digester was provided  with a roof  top crane for  removal  of
     the heat exchangers  when required.

     The proposal  was for elimination of the permanent cranes, and use of rental
     cranes or use of temporary  false  work when removal  of the heat exchangers
     was required. Removal  was  estimated  to be  once every  five  years  or  less,
     based on past  experience.

Substitute High-Rate Anaerobic Digesters for Low-Rate

     The original  concept used two gravity  thickeners  for a combination  of  pri-
     mary  and rotating  biological  contactor  secondary  sludge.  The  thickened
     sludge was to be anaerobically digested using  two  stage digestion.  Two  pri-
     mary digesters provided a  35 day detention time and  they  were equipped  with
     floating  covers. Secondary  digesters  were equipped  with  fixed  covers.  The
     four  digesters  and the  two  thickeners  were  clustered around a  central

     The proposed  change was to  construct  three high  rate digesters.  The  total
     detention time would be 14 days with  two  of the digesters in operation and
     the third utilized  as  a holding tank. The  three  digesters and  two gravity
     thickeners would be  clustered  around an enclosed pentagon shaped sludge  pump
     station and boiler room.

Reduce the Number  of  Digester Gas Mixing Compressors

     The  original  design called  for 5 gas compressors.  Each primary  digester
     would have one operational  and one standby compressor and a fifth compressor
     was to be used for the two  secondary digesters.

     In the proposed  design,  the secondary digester mixing compressor and one of
     the standby compressors for  the  primary digesters  were eliminated. When  sec-
     ondary digester  mixing was  required, it was  proposed to use the  standby com-
     pressor for that purpose.

                                                                PROCESS EQUIPMENT
SLUDGE DISPOSAL  -    . ,               '                 '            "''::''.-;.''

Haul Liquid Sludge and Eliminate all Sludge Treatment             •

     The original design concept included  aerobic  digestion plus sand drying beds
     for the first five  years of plant operation. Phases  II & r II of  the  treat-
     ment  facility,  .which  were  to occur  sometime  after  the  first  five  years,
     included aerobic digestion plus vacuum filtration.

    , The proposed  concept  recommended hauling  liquid waste activated  sludge and
     primary sludge  directly to a  treatment  plant  20  miles away  and  completely
     eliminating all sludge  treatment.                                .  ". •   -

Eliminate Sludge Storage Tank

     The regional  solids  handling facility  included a holding tank  to  receive
     sludge which was hauled from other treatment facilities.  A pump station was
   •  provided  to  transfer  sludge  from  the  holding   tank   directly   to  the

     The proposed  concept  recommended  pumping sludge directly  from the trucks to
     the anaerobic digesters, eliminating the need  for  the sludge  storage tank
     since the daily volume  of sludge  to  be  hauled  in was  only a very small per-
   •  centage of the total  sludge in the digesters.               .'"'-•

Use Pipe Line Rather Than  Trucks to Transport Sludge ',           '  „  :..   •-',.

     In  the  original concept the   digested sludge was hauled using 5500• gallon
     trucks to an  ultimate disposal site  approximately five miles from the treat-
     ment plant site. About  11 truck loads a  day were required at design  capacity
     of the plant.                                                      •

     In  the  proposed  concept an   18-inch pipeline  was  used  to  transport  a 4%
     solids sludge to the  ultimate  disposal site.                         .

Use Throttling Vanes  in  Place of Variable Speed Drives on Induced Draft'Fans

    • The  original concept proposed to  use  four induced draft  fans  on  sludge
     incinerators. The  fans were proposed to have variable speed  drives  to pro-
     vide adjustable  air inputs.                  ~                '   •

     In  the proposed concept two ID fans  were  used  with  throttling  ID fan inlet
   -  vanes rather  than variable  speed  drives.                        •

Preheat Incinerator Combustion Air                                    •

     The original  concept  utilized conventional combustion air injection without

     The proposed  concept  would  install  a type 304 stainless steel heat exchanger
     in  the  bridging between the incinerator and  scrubber thereby preheating the

                                                                PROCESS EQUIPMENT
                                                                Sludge Disposal
     combustion  air to 800  degrees  Fahrenheit prior to  injecting air into  the

Eliminate Incinerator Ash Storage Basin

     An impingement type scrubber was planned  to  be  used on a sludge incinerator,
     with the flow  from  the  scrubber passing to a storage  basin.  After settling,
     water from the basin would be returned to the scrubber system.

     Use of a cyclone separator was  proposed as a substitute  for  the  ash  storage
     basin. Water from the impingement scrubber would be pumped by a booster pump
     to the cyclone separator,  and  after separation  the  clarified  water would be
     recycled and  reused in the  impingement scrubber.  Ash would be  disposed of
     identically in either scheme.

Eliminate Sludge Storage Bins

     The original design included sludge storage bins to  hold sludge  after being
     removed the sludge drying beds.

     The proposed  concept recommended  eliminating  the  sludge  storage bins  and
     hauling the sludge directly to  a landfill

                                                                      SITE LAYOUT
       ,-,.-•-.     .  •    !  -.-..-...-..  .:,.  CHAPTER 4        .  ':-•.••::..   •-./...  ...'":•

                        V       .     EARTHWORK       .          ' '  .      ...:..-..-...

Use Reclaimed Rock From on  Site Excavation for Construction of Breakwater

     The original concept proposed  sheet steel piling for a 700 foot long  coffer-
     dam at an existing lagoon.

     The proposed concept would utilize rock,  excavated.. from another part of  the
     construction  site,  to  cover  the  surface  of  the  cofferdam.  Additional
     material would be  required to  make the cofferdam impervious.

Reduce Final Grade

     This project was to be constructed  in a swampy area,  and  costly fill mate-
:     rial would have  been required  to  raise the entire site.          .

     The proposal was to lower theentire  site elevation (not the structures)  by
     1* . This  would make the "entire site  more prone  to flooding,  but would  not
     make  the  treatment facilities themselves  more suscepible  to  flood  damage.
     Some redesign would be necessary  to implement the proposal.

Reorient Plant and Change Site Grading to Eliminate Handrails     '

     In  the  original concept,  on-site influent piping  was  conveyed through  sev-
     eral  hundred feet of  pipe tunnel before reaching the" .influent  structure.
     Also,  finished  grades  were 6- to 12-inches below tank 'tops',  and  aluminum
     handrails were  used around each of the basins.

     The proposed concept recommended reorientation. of the 'plant  to put  the  infl-
     uent  structure  closer to  the  location where the  influent  sewer  entered  the.
     plant  site.This  reorientation also eliminated "back  and  forth"  conveyance
     of  flows  on  the plant  site. Another modification was  to. lower the  finished
     grade  30- to  36-inches  below the  top of  the various  structures,  thereby
     eliminating the  need for the handrails around the basins.

Eliminate Retaining  Wall and Regrade                      ..„•..';     •

     The original concept  proposed a retaining wall to be located between a pro-
     cess building  and the  roadway.

     The  proposed  concept  would eliminate  the retaining  wall  and  regrade  the
     slope.'  -' •    -           •                       •     • ••-..   '._   -.'-     ,:  • •.

Use Precast  Panels  Instead  of Retaining Wall

     In  the original  concept  a  retaining  wall was  used  to  support  an  earth
     embankment.  Construction  was  to  be a  standard cantilevered wall with  back-
     fill  behind the wall  and a lower finish grade in  front of the  wall.  Along
     the same area  sheet  piling was  to be  placed during  construction  and  then
     later cut off  and replaced by the retaining wall.

    .                 ' •      •• •          89        •.:.-.•,;.•..- :  •..•-•'..-

                                                                      SITE LAYOUT
     In the proposed  concept the steel piling  would  remain in place  and  precast
     concrete panels are set behind the piling flanges to  form a  retaining  wall,,
     Figure 30 shows sketches of the original and proposed  concepts.

Use Open Cut Excavation in Lieu of  Coffer Dam Construction

     A  large  interceptor  pumping  station  was planned  to  be  constructed  using
     pilings,  bracing, excavation,  and deep well dewatering. EJcav-atLon would be
     using a clamshell bucket

     The proposed concept recommended  elimination of  the  complex  bracing,  pilings
     and dewatering by using open cut  excavation.

                                                               SITE LAYOUT
                       EXCAVATE &

                      CUT-OFF H-PILING
                 II  H
                                                     PRECAST CONC PANELS
Figure 30.  Replace retaining wall with precast panels in H-piles.

                                                                      SITE  LAYOUT

Use Narrower Entrance Road

     The original  concept used two 24-foot  divided entrance roads with  complete
     curbing and gutters.

     It was proposed to eliminate one  of the divided  roads,  and eliminated  the
     curb and gutter from the remaining road.

Delete Roads Required for Future Expansions

     The original concept included roads required  for not  only  the initial  phase,
     but also all subsequent phases of  the treatment facility.

     Deleting the roads required for future expansions of  the  treatment  facility
     was proposed.  This change would not affect traffic  flow  or access for  the
     initial phase.

Use Filter Fabric Under Paved Areas

     The site for the treatment facility had previously been a landfill, and  the
     soils report indicated the probability  of continued settlement.  A minimum of
     2-foot of  sand and gravel base material was  recommended  for plant  roads  by
     the soils  report,  and in  some locations,  up to 4-foot of sand and  gravel
     base material  were recommended.

     The proposed was to  excavate  to 20-inches below finished  grade  of  all paved
     areas and  to install fabric material prior  to spreading the base material.

Reduce Roadway  Width

     The original  concept provided a 20 foot wide paved  and  curved  access road
     around the perimeter of the plant.

     The  proposed  concept reduces  the paved  width  to   12   feet  with one-way

Change Road Paving

     The original  concept proposed  a  paved access road  around the  perimeter  of
     the treatment  plant.  The  pavement  consisted  of  a  10   inch subbase,  six inch
     processed  aggregate  base,  and three inch paved road section.

     In the proposed concept oil treated gravel  would be used on the  access roads
     around the plant perimeter. The  gravel base  would be 12   inches  of crushed

                                                                      SITE  LAYOUT
Revise Site Roadways and Reduce Roadway Width

     In the original  concept an extensive network  of various width of  roadways,
     multiple parking  areas,  and numerous paved  turn around or access  areas  for
     the various buildings of the treatment  units were  used.

     In the proposed concept roadway widths  were  reduced from 24 feet  to 18 feet,
     which was considered  ample  for the low speed  travel which  would  be required
     at  the  plant  site.  The parking  areas were also  revised  and reduced,  but
     still remained functional.

                                                                      SITE LAYOUT

Simplify Return Activated  Sludge Flow Balancing Scheme

     In the  original  concept, return activated sludge (RAS) flow would  be  split
     by an  instrumentation based  ratio scheme  utilizing  flow meters  and  throt-
     tling valves  to  determine the relative  proportions  of sludge  to  each  aera-
     tion  basin.   The  ratio  to  be utilized  would  be entered  by  the  operator.
     Normally, 1/2 - 1/2 for  the first  stage  aeration and  1/3  - 1/3  - 1/3 for the
     second  stage  aeration.

     In the  proposed  concept,  RAS flow would  be  routed  to  the aeration  basin
     influent  splitter boxes and  split with the  influent, thus  eliminating the
     complicated instrumentation  system. Figure 31 shows  schematics of  the  orig-
     inal and proposed schemes.

Eliminate Pipe Gallery

     The original  design proposed  air^pipe gallery along  the end of the  aeration

     The proposed  alternative was  to  eliminate  the  gallery and  to either bury the
     pipes or to support them from exterior walls  above  grade.

Mpdify ScumHandling Systems

     Scum from secondary clarifiers  and backwash  water from tertiary  filtration
     facilities was  to  be transported  to a reclaimed  water clarifier.  Settled
     material from the reclaimed water  clarifier would then go  to a waste  sludge
     pump station, and scum off the top of the clarifier  would be  pumped to the
     Sludge  Disposal  area  for further  concentration and  incineration. All  lines
     which were to carry scum or the  scum/backwash  were  lined  to prevent  build-up
     of scum in the pipe.

     The  proposal  was  based upon both eliminating the  dilution  of  scum  with
     filter  backwash  water  and then reconcentrating the  scum  in  the  reclaimed
     water clarifier,  and eliminating  as  much  piping as   possible,  particularly
     lined pipe.  Based on  these  two concepts, the  following  changes were  pro-
     posed:  eliminating the  reclaimed  water  clarifier,  pneumatically  ejecting
     scum from the final clarifier directly to  the  Sludge  Disposal Area,  elimina-
     ting the  separate lined pipeline  for scum/backwash,   and conveying  backwash
     water directly to the plant drain  through  an unlined  pipe.

Use PVC to Replace Ductile Iron Pipe

     Potable and non-potable water systems between 3-inch and 8-inch  were  orig-
     inally  designed to be of ductile iron pipe.

     Class 160 PVC (ASTM  D2241)  was  proposed  as  a  replacement  for the  ductile
     iron pipe.

                                                                    SITE LAYOUT
                                         MAGNETIC FLOW METER &
                                         THROTTLING VALVE ( TYP)

                                                 2ND STAGE
                                                                 TO FINAL,
-*ป. '

                            ORIGINAL CONCEPT
                                               . 2ND STAGE
              1ST STAGE

                           PROPOSED CONCEPT
     Figure 31.  Simplify  return activated flow balancing  scheme.

                                                                      SITE LAYOUT
Simplify Secondary Clarifier Flow Distribution and Piping

     Five  equal  diameter circular clarifiers were  to  be  utilized in the original
     concept.  Flow to the clarifiers was  to  be divided equally  by  using  a knive
     gate  valve and  a flow  meter for  each clarifier.  After flow measurement,
     42-inch  pipes conveyed  flow to  each clarifier  with the nearest  clarifier
     being 45* from the  distribution  vault and the furthest one being 230' away.

     A  simplified  approach  was  proposed  for  flow  splitting between  the  five
     clarifiers. The  knife gate valves and flow meters were  eliminated, and were
     replaced by weirs and slide  gates.  Piping to  the clarifiers  was changed from
     the  original  42-inch size,  the proposed sizes  to  be  a  function  of  the
     distance  to  each clarifier.  In the proposal,  distribution pipe sizes ranged
     from  36-inch  to  48-inch.

Reduce Size of Return Activated Sludge Pipeline

     Originally,  1200 feet of  36" diameter return activated  sludge line  capable
     of handling a peak  return sludge flow of  15  MGD was  included  in the plans.
     An average operating  condition for  the  pipeline  was  7.5  mgd.

     Concern  was  expressed over  solids  deposition  in   the  pipeline.   Scouring
     velocity probably would  not  occur at  the 7.5  mgd flow rate  in  the  36"  pipe.
     Analysis  indicated  that a -24-inch- pipe  should  be  used  to  create scouring
     velocity  at  the  7.5 mgd flow rate. Power  costs  were increased somewhat  by
     use of the smaller pipe.

Splitting  of Return and Waste Activated  Sludge

     A flow splitting chamber was used  at  the  secondary  clarifiers to  split  the
     return activated sludge  (RAS) and the waste activated sludge (WAS). Separate
     parallel pipelines were  then  used for  about 800  feet from the  flow  splitting
     chamber to  the dissolved  air flotation thickeners  (WAS  piping)  and to  the
     head  of the aeration basins  (RAS piping).
     Elimination of the RAS/WAS splitting  chamber  was  proposed and  a single  pipe-
     line  was to be used to the DAF units. RAS  flow  was  to be metered  from  this
     pipeline to the  aeration basins using two  metering pumps.

Replace Tunnels With Buried Structural Slab

     The plant under  consideration was  to  be constructed  on  the site  which  had
     previously been  a sanitary landfill.  This necessitated the use of  piling  to
     support the  tunnels which provided access between  the  treatment  processes
     and in which  piping was  located. Because  of  the possibility of methane  gas
     seeping into  the  tunnels,  a positive ventilation  system  and  a hazard-warning
     system were required.

                                                                      SITE  LAYOUT
     The proposed concept recommended use of a buried structural  slab  in  place  of
     the tunnels. Piling would  still  be required because of high  groundwater and
     poor  subsurface  conditions,  and   the  structural  slab  would  have  to   be
    .attached  to the  piling.  The  proposal would eliminate  heating, lighting,
'  .   ventilation and drainage for the tunnels.

Substitute Steel for Ductile Iron Inside Piping

     The original  concept used  ductile iron pipe with flanged  fittings • on all
     process scum, sludge, air, potable water and  non-potable  water piping.

     Standard steel piping  with welded fittings and  sleeve type  joints  was pro-
     posed as a substitute.

Relocate Influent Force Main, Outfall,  and 36" Storm Drain  Into  a Common  Trench

     In  this  study,   the  treatment  processes  and plant  layout  could  not  be
     changed,  but  relocation of the influent  force main,  the  outfall, and  an
     on-site storm  drain was identified as" an :area  of cost  savings. The  plant
     site  was  crossed  completely or partially  by an  influent  force main, the
     plant  outfall,  and  a  storm  drain.  Each  of  these   facilities  was  to  be
     installed separately in its_ own  trench.	 	                 .     ,

     The proposed concept  recommended relocation of these  facilities  so  that use
     of a  common trench was possible for much of  their length. The original and
     proposed layouts  are shown  in  Figure 32.                      ,

Use Class  IV Reinforced Concrete Pipe for Final Effluent Piping

     The original concept  proposes to use prestressed concrete  cylinder  pipe  for
     the effluent piping.               -••'_'     .

     In the proposed concept, Class IV reinforced concrete'pipe  would be substi-
     tuted for the original concept.

Revise Air Piping Material

     In the proposed concept  all air piping was to be stainless  steel whether  it
     is buried or exposed  to the atmosphere.          ,

     In  the  proposed  concept  the exposed outside piping would  remain  stainless
     steel but all other piping would be carbon  steel or cast iron.

Use Open Channel for Storm Flow Instead of  Storm Drain                  ,

     The original concept  calls for the construction of two  60  inch  storm drains
     to intercept an existing storm drain.

     In the proposed concept, the two 60-inch  pipes would be used only where open
     channel  flow was not  possible.  An  open  channel  would  be used  for  the
     remainder of the  diversion.

                                           SITE LAYOUT
     O O O Q
P Q  Jjo o
     O O
            O  JJQ o

                         	36"STORM DRAIN

                         	54" OUTFALL

                         	54" INFLUENT FORCE MAIN
                         	18" STORM DRAIN
Figure 32.  Reduce length of yard piping.

                                                                      SITE LAYOUT
                                                                     Plpln g   -
Delete Pipe and Gates to Drain Head End of  Aeration Tank

     Aeration basins in the  plant  were divided into four stages  to  allow some of
     the aeration basin tankage  to be taken out of  service  in  the winter 'months.
     Gates were  provided at both  ends of  the  aeration  basins,  even  though only
     the later stages of the aeration basins would be taken out of service in the
     winter.    '    " '   •   :	 ." '   ""  "\.   •   • "  '"•     "••.'-   -       .  '   " •   '••

     In the proposed  concept all drainage  would be removed from  the  tail end of
     the basin,  eliminating approximately  half of  the  interconnecting  pipe  and
     four sluice gates. A  sketch showing the deleted piping is in Figure 33.

Relocate Splitter Box for  New Secondary Clarifiers                     ,

     Two new secondary  clarifiers were  to be added to a  plant which  had four
     existing clarifiers.  Flow  to  the existing clarifiers was, split by a four-way
     splitter  box.  The original  concept  called  for  the  modification  of this
     four-way  splitter box  into a six-way splitter  box  which  would serve both
     existing and new  clarifiers.

     'Because the new  clarifiers were not in  the same area  as the existing  clari-
     fiers  and  because  the pipe  to  the  existing  four-way splitter box passed
     adjacent  to the new  clarifiers, it was  proposed that the  flow  for the  new
     clarifiers  be  split out ahead of the existing  four-way splitter  box.   There-
     fore,  the new splitter box would  split  the. flow for the two new clarifiers,
     and the flow  to  the existing four-way splitter box. The proposal resulted in
     a savings  of  piping,  and  eliminated  modification of  the existing  splitter
     box.  Sketches  of the original and proposed concepts are shown  in Figure  34.

 Relocate Sludge  Pumping Station More Centrally to Multiple Clarifiers

     Separate  waste sludge  arid  return sludge lines were used  from  six clarifiers
     to the sludge pumping  station.  Due to  the layout of the plant, some of these
     pipes were  relatively  long, and plugging was  a potential  problem. Horizontal
      centrifugal pumps were planned  to be  used for  sludge pumping.

      The  proposed  concept suggested  eliminating  the long pipe runs by locating a
      sludge pumping station between each  bank of two clarifiers.  Vertical  mixed
      flow pumps were * proposed  for the  waste  activated  sludge,  and vertical  cen-
      trifugal  pumps were proposed for  the  return  activated  sludge.

 Combine Mixed Liquor Suspended  Solids  Piping

      In the'.'" original 'concept, three mixed  liquor  suspended  solids lines  were
      required.  One line  was to two  existing intermediate  clarifiers and  the two
      remaining  lines were to two  new intermediate clarifiers>

      In the proposed  concept,  the MLSS piping was combined to  the  greatest pos-
      sible  extent.  Figure  35 shows  a  sketch  of  the  ^original  and  proposed
      concepts.                   •

                                                               SITE LAYOUT

ป T
1 * 1 ' 1
rH K i t 1
EXJ ea
^ B

                                                         DRAINGAGE PIPING
Figure 33.  Delete drain pipes and qates from head end of aeration  basin.

                           SITE LAYOUT

                                                  SITE LAYOUT
                       ORIGINAL CONCEPT
                       PROPOSED CONCEPT
   Figure  35.  Simplify mixed liquor piping.

                                                                     SITE LAYOUT
       ite Alt
                 itive Materials for Large Diameter Stainless Steel Air. Headers
     The  original design  concept included  using  stainless steel  air  piping for
     areas  above the primary  effluent  and mixed liquor  channels,  and  for. piping
     in the runs from the  blowers to the aeration basin.complex.

     By enclosing the mixed liquor  in  a conduit,  the air headers  on the edge of
     the aeration basin.could be supported on top of the mixed liquor conduit and
     would not  be  exposed to  the  mixed liquor.  Pipe  material  could  then be
     changecTfrom stainless  steel  to  some other  material  such  as  welded  steel
     pipe,  where corrosive conditions  did not exist, use of fusion-bonded epoxy-
     coated and lined  carbon steel pipe was recommended.

Eliminate Mixed Liquor Distribution Piping

     The initial  design  used piping to distribute mixed  liquor to the  aeration
     basins.                                                                  ,

     It  was  recommended  that the mixed liquor distribution piping  be  eliminated
     and adjustable weirs off the  center channel be used  for mixed liquor flow
     control.   -

Revise Chlorine Contact Tank  Piping

     Larcre diameter buried valves  and fittings were originally proposed for the
     chlorine contact  tank piping.       "                                     •

     Elimination  of most  of  the buried valves  and fittings  were proposed by add-
                                                                      SITE LAYOUT
     It was recommended  that the discharge pipes  be  placed above ground  to  pro-
     vide better access and  ease of maintenance.

Route Return Flows to Primary Clarifiers  Rather Than  To  Headworks

     The  plant drain,  thickener,  supernatant,  and  filter press  filtrate  were
     piped back to the headworks of the plant in the  original  design.

     The proposed concept  recommended routing the  return flow piping  to  the  head
     of the primary clarifiers  rather than  to  the  plant  headworks.  Plant  flow
     monitoring was  improved because  returned  flows would  not distort  influent
     flow measurement at the Parshall  flumes.

Eliminate Air Pipe Insulation

     In the original design, the  air blower discharge  piping was provided  with

     The  proposed  concept recommended eliminating the  insulation  from the  dis-
     charge pipe because  the pipe  was not considered  to be  hot  enough to  be  a
     safety hazard.

Piping to Secondary Clarifiers

     Flow from  rotating  biological contactor secondary  treatment  was to  be  con-
     veyed by four separate  pipes  to  the  four secondary  clarifiers.

     Use of a single pipeline to a splitter box in the  center of the  four clari-
     fiers was proposed. Slide gates  would  be used in the splitter  box to  propor-
     tion flows between  the  clarifiers.  Figure 36 presents sketches  of both the
     original and the proposed concepts.

Increase Size of Return and  Waste Activated Sludge

     A pure-oxygen activated sludge  plant was designed  with the return  activated
     sludge and waste  activated sludge piping  sized for a 2% solids  concentra-
     tion, based upon on-site pilot studies.

     The proposal recommended re-sized sludge piping based upon a  solids  content
     of 1% rather than 2%. One percent solids was  cited  as  being more  representa-
     tive of operating full-scale pure oxygen plants.

Revise Scum Piping

     In the original concept, separate scum piping  was  used  between two  inter-
     mediate clarifiers  and the pump station which  housed the  scum pumps.  Two
     scum pumps were provided for each clarifier.

     The proposed  concept  recommended  using  a  common scum  line  and  common  scum
     pumps. Sketches of  the original  and proposed concepts are  shown in  Figure

                                                           SITE LAYOUT
                  RBC UNITS
                                        2ND CLAR1FIER
                        ORIGINAL CONCEPT
                                            30  TYP

                                          2ND CLARIFIER
                         PROPOSED CONCEPT
Figure 36.  Use single mixed lj3uor pipe to secondary clarifiers.

                                                 SITE LAYOUT

PIB          P2A
              ORIGINAL CONCEPT
                    SCUM PUMPS
Figure 37.  Simplify scum handling system.

                                                      SITE LAYOUT;
                                                      Equipment  & Process Layout

Rearrange Sludge Building

     In the original concept major modifications to the incinerator  were  included
     for providing the option of operating  in a pyrolysis mode.  Dewatering equip-
     ment would be converted to a filter press so that the  combined  primary/ sec-
     ondary sludge will  be of  sufficient  dryness for autogenous  combustion.   A
     waste heat recovery boiler was also in the design to supplement the  existing
   .  heating system.                                            -.   .    .   .

     In the proposed concept the pyrolysis  option was deleted.  It  appeared unjus-
     tified since the new dewatering  equipment  would allow  the  incinerator  to
     operate autogenously.              !_

Use Tertiary Filter Backwash Water for  Incinerator Scrubber Water

     In  the  original  concept,  two recycle flows were  returned to  head of  the_
     aeration basin. The first  of these was scrubber water  from the  incinerators,
     which used plant  effluent  for the  original supply. The second of these flows
   •  was tertiary filter backwash water.

     The proposed concept  recommended using tertiary filter backwash water as the
     supply for the incinerator scrubber. This  concept eliminated  one half of the.
   'return flow. A sketch of both the  original and proposed concepts is  shown in
     Figure 38.             ,                                                    -•  .

Combine Grit Removal and Preaeration  in a Single  Structure

     Grit removal and  preaeration were  originally designed  as separate operations
     in  separate  structures.

     The proposed change used an aerated  grit  chamber  to  combine grit removal and
     preaeration  into  the  same  operation  and  structure.

Reduce Number  of  Clarifiers From 5 to 4

     The plant under  consideration was  50 mgd,  and in  the future was to undergo a
     25  mgd expansion. For the initial 50  mqd phase, 5  secondary  clarifiers were

     Using  4  instead of 5  secondary  clarifiers  in the 50  mgd  phase was  proposed
     tcT~simplify  the addition  of  the future 25  mgd phase  (2  clarifiers)  and
     result in 6  clarifiers of  equivalent, size at ultimate  capacity.

Make Site More Compact                                         -     -- -

     To construct the treatment facility at  the  site selected, about  65% of the
     site  would  have  required dewatering  during construction.   Additionally,   a
     rather extensive ditch system would have  been required for groundwater ele-
     vation  control   and   for  stormwater.  The  original  design  was  costly  in

                                                            SITE LAYOUT
                                                            Equipment & Process Layout
            2.5 MOD WATER SOURCE
                     TERTIARY FILTERS
                                                                AHEAD OF
                             ORIGINAL CONCEPT
                                                   BASE CASE PUMP
                                                                AHEAD OF
                             PROPOSED CONCEPT
               Figure 38.  Scrubber  water recycle streams.

                                                      SITE LAYOUT
                                                      Equipment & Process Layout
     construction,  and the  treatment  facilities  were  spread out  on  the site
     substantially.                                             -.     ' .

     Compacting the plant onto  the  site was proposed as  a  means  of reducing the
     intitial capital  cost,  site dewatering, road  length and  the  cost of elec-
     trical distribution. A  secondary benefit was  the  availability of more land
     for future expansion when required.

Relocate Clarifiers Closer to Aeration Basins

     A plant  service  road and  a flood control  channel were placed between the
     primary clarifiers and the aeration basins.

     Relocation of the flood control channel and the plant service road were pro-
     posed. This  allowed the primary  clarifiers and  the aeration  basins  to be
     located about 30 feet closer together.

Eliminate New Piping Between Secondary Clarifiers and Chlorine  Contact Tank

     At an existing plant which  was being  expanded,  a box conduit was  used to
     convey secondary effluent to the chlorine contact  chamber. Although the con-
     duit  could  handle the original plant design  flow of  27  mgd,  it  could not
     carry  the  new ultimate  design flow  of 36  mgd.   The  design for  the plant
     expansion abandoned the existing box conduit arid used a new 66-inch diameter
     reinforced concrete pipe.

     The proposed concept recommended continued use of  the existing  box structure
     until  its  capacity was reached,  and then adding  a parallel  pipeline at  a
     later date when future flows were more  definitively  known.

Modular Design of Equipment

     The  original  design  utilized  a  complex  of  circular primary clarifiers,
     rotating biological contactors, and a  complex  of circular  secondary clarifi-
     ers.  Primary and secondary  sludge pumping stations were  in separate  loca-
     tions, as was the effluent  pumping station, process  return  pumps,  and the
     control building.

     The  equipment. was rearranged  into a modular  concept  utilizing rectangular
     primary  and  secondary  clarifiers,  and channels  for  conveyance  of  flows
     between unit processes. A  common pipe gallery was proposed, and all pumping
     facilities were  housed in the  control  building.  Figure 39 shows  schematics
     of the original and proposed systems.

Rearrange  Plant Layout

     The  original concept  utilized a spread out  concept with   little common wall
     construction.  There was a high degree of  "back  and  forth"  conveyance of
     flows on-siteป                                              .

                                                        SITE LAYOUT
                                                        Equipment & Process Layout
                       CONTROL GATES (TYP)
                           RBC  SYSTEM
                                            LIQUOR   SECONDARY CLARIFIERS
                       PRIMARY EFFLUENT
                       DISTRIBUTION CHANNEL
                                   LIQUOR DISTRIBUTION
    •RAS & WAS
                            ORIGINAL CONCEPT
                                       /• CONTROL GATES ( TYPJ

                           RBC SYSTEM  \        SECONDARY CLARIFIERS
                      PRIMARY EFFLUENT
                      CHANNEL WITH
                      GALLERY UNDER
                           PROPOSED CONCEPT
             Figure 39.   Modular design of  unit processes.

                                                      SITE LAYOUT
                                                      Equipment  & Process Layout
     The proposed  concept  was a more  compact arrangement,  using about 25%  less
     land area. Piping  requirements  were substantially reduced and a high  degree
     of common wall construction was utilized.

Flow Equalization After Primaries

     The- original concept was to construct flow equalization basins ahead of  pre-
     liminary  treatment,  which  would require  mixing  and   aeration  to maintain
     suspension of heavy materials.

     The alternative is to place the flow equalization  after preliminary and  pri-
     mary treatment. The  effect of this  change  would  reduce  the number of  pump
    ' stations  required  from  two  to one .It would  also  make  the  water storage
     easier  by removing the  majority of  the grit,  screenings  and  the primary;
     sludge. The removal of the heavy  loadings prior  to equalization  also reduced'
     the requirements for aeration in  the equalization  basin.  ,

Relocate Air Blower Building  to Slab on Grade

     In the  original  concept, an air  blower building  with  four  air  blowers  was
     located on the  ground floor of  an intermediate pump  station building.  The
   ,  blowers were positioned  over the  below-grade dry well  for a  pump station and
     because of their location,  the blowers'require special structural design to
     support  them and  dampen  the  associated  vibrations.  This  location  also
     requires  over 200 feet of 42-inch air header pipe  to convey  the  air from the
     blowers to the aeration  tanks.                                           ,

     In the  proposed  concept  the blowers were  located  in a slab-on-grade  build-,
     ing,  thereby requiring  less  structural support  and  .vibration  dampening.
     This proposed building would be  located with  a common wall  to the new aera-
     tion tank which.also  can reduce the cost of the building and the length of'
     the required 42-inch air header.

Relocate Odor  Control Scrubber and Blower to Outside  of Building

     In the  original  design,  the odor control scrubber  and blower were located
     within  the screening building..

     The proposed  concept  suggested locating the scrubber and blower outside the
    ; screening building on a  concrete  pad. This allowed the  screening building to
     be reduced in size.  A sketch showing the  original and proposed concepts is
     shown in  Figure 40.

                            SITE  LAYOUT
                            Equipment & Process Layout



3 c
u/ "









                                               SITE LAYOUT    v:     \    ;  .
                                               Hydraulics and Hydraulic Gradeline
HYDRAULICS AND HYDRAULIC  GRADELINE                                         '

Lower Plant to Lessen  Influent Pumping

     A new treatment facility was  layed put with an influent pumping station, and''
     then gravity  flow, through the plant into an adjacent river. The plant facil-
     ities were  located  at  a high  enough  elevation to  allow gravity  flow  even
     during 100 year flood flow in the river. Accommodation  of  this gravity flow
     condition during, the .100  year flood  flow  resulted in  pumping requirements
     which were substantially in excess of  normal requirements.

     The proposed  concept recommended  lowering  the plant hydraulic  gradeline  to
     an elevation  which would allow submergence of the weirs  of the final clari-
     fier (but not the final clarifier itself) during a'  100  year flood.  The pro-
     posal resulted  in a  significant  life  cycle energy  savings.  Additional  sav-
     ings might  also  result  by  lowering  the plant  even further  and  adding  a
     standby  effluent  pumping  station  for  flood  situations  approaching  the  100
     year flood.

Reduce Filter Structure Height

     The original  concept proposed using a 12.75'  filter operating  depth and  2^_
     of filter freeboard  to  achieve 24  hour filter runs  at peak  rates.      •

     The proposed  concept recommended reducing the filter  operating depth to 10'
     and the  filter freeboard to 1.5'.

Use Flow Splitter  Boxes

     The original  concept provided a flow control structure  with flow  meters and
     automatic butterfly  valves to  split the primary effluent  and  return sludge
     between the aeration tank pairs. Tlp-S  arrangement was  alsp  used to limit the
     flow-to  the secondary process, with excess  primary influent to be  bypassed'
     to the chlorination  facilities.         ;

     In the proposed  concept  two  weir-boxes  were provided  to  split  flows,  one
     weir, box for primary effluent  and one '• if or  return sludge.  The weir  boxes
     would have the  capability of  splitting the  flow either 1/2:1/2  or 1/3:2/3
     between the aeration, tanks.  Also,, steel  bypass  launders and weirs  would  be
     provided in  the primary  tank effluent  channel  to   collect overflow to  the
     chlorination.              	                   .,   :        .

Lessen Head on Effluent Pumping Station

     The original  design  for a plant included future effluent filtration facili-
     ties in the hydraulic profile of the plant. With inclusion  of  these facili-
     ties,  a  relatively  deep  effluent pumping  station was  required.  Without,
     inclusion of  these future  facilities,only  a relatively  shallow pumping sta-
     tion  was  required,  and  pumping would only  be   required  during  flood
     conditions in the adjacent river.

                                              SITE LAYOUT
                                              Hydraulics and Hydraulic Gradeline
     Since the  future requirement for effluent  filtration was uncertain, it was
     proposed  to raise  the effluent  pumping station  to  the  highest  elevation
     possible for the first stage plant consbraction. Such an  elevation  increase
     then allowed gravity flow during  all  times except  flood conditions in the
     adjacent river,  when effluent pumping was  required.  Overall, eight feet  of
     elevation was saved.

Grit Removal After Raw Sewage Pumping

     The  original  design  located the grit  removal,  comminution  and raw sewage
     pumping in a deep gravity fed structure.

     The proposal was to place the grit  removal and comminution  downstream  from
     the raw sewage  pumps, and raising the  grit removal and  comminution  facili-
     ties to at-grade.

Raise Elevation of the Influent Screw Pumps

     In  the original concept,  the hydraulic  grade  line in the  pump  station
     influent pump trough  was 5 feet above the top  of the screw pump.

     The  proposed  concept  recommended  raising  the  bottom  elevation  of  the
     influent pump trough  by approximately 4' thereby placing the  hydraulic  grade
     line  only 1'  above the top  of  the screw.  The proposal  would shorten the
     screw by  8'  and reduce the  horsepower  required from  75  to  60.  A  sketch  of
     the original and proposed concepts is presented  in Figure 41.

Lower Primary Treatment  Processes and Eliminate  Influent Pumping  Station

     The  original concept provided hydraulic profile with  pumping required  prior
     to the new primary  settling  tanks.  The primary  tanks  were located  on  a  high allow  for gravity flow through roughing  towers with  a  24'  media
     depth, and then to  intermediate  clarifiers.  Effluent from the  intermediate
     clarifiers  was  then to be pumped  to aeration  tanks.  During  low  flows,  some
     of the intermediate flow was also  to be  recycled to the  roughing towers.

     The  proposed concept lowered the new  primary  clarifiers to allow  gravity
     inflow, thus eliminating the primary pump  station.  The  roughing towers  were
     ceduced in height  by using  only  20'  of media  depth  and  lowering the  base  of
     the  towers to allow for  gravity  flow into  the  towers from the primary clari-
     fiers. This new hydraulic  profile only required pumping of roughing  tower
     effluent  to the intermediate  clarifiers,  thereby  eliminating  one  of  the
     pumping stations.

                                                  SITE LAYOUT                .  . •  . .
                                                  Hydraulics & Hydraulic Gradeline

              Figure  41.   Raise .influent screw pumps.

                                                                    SITE  LAYOUT

Eliminate Tunnels

     In  the  initial design,  550  ft of  tunnel connected the  primary tanks  pipe
     gallery with the digesters,  secondary  tanks  pipe  gallery,  and the operations

     The  proposed concept  recommended constructing 425 ft of  pipe  trench  with
     approximately  350   ft  of protected surface  walkway,   thus  eliminating  the
     tunnels.  The proposed plan  resulted in  a  significant initial  construction
     cost savings and eliminated  the tunnel drain system and  sump  pump.  By plac-
     ing  the  small  pressure  piping in a surface  pi-pe  breach, accessibility  for
     maintenance was greatly  increased.

Eliminate High Mast Lighting

     Five High Mast Lighting  units were originally used to  light  the plant site.
     Each mast was equipped with  multiple 1,000 watt high pressure sodium lamps.

     Elimination  of  the High Mast units was  proposed,  with substitution  of  25'
     high"roadway type  luminares. 400  W mercury  vapor, metal halide or 250 W high
     pressure  tiocllaxi  lamps  were  proposed. Cost savings  were in  both initial cost
     and annual electrical  costs.

                                                         BUILDINGS  OR STRUCTURES
                                                         .Size        ,
                                   ^CHAPTER 5.,,.

                             BUILDINGS OR STRUCTURES

Reduce Size of Garage

     The original concept  provided an enclosed garage  with parking bays 20  feet
     wide and with 20 foot high clearance.

     The proposed concept  recommended reducing the bay_ width  from 20 feet to  16
     feet wide  and  the ceiling would be lowered  from 16  feet  to 10 feet,  thus
     reducing the volume of the entire building.

Reduce Garage Floor Slab Thickness

     .In the original concept a garage was provided with a s lab on grade.  The  slab
     was 8-inches thick.

     In the proposed concept  the  slab would be  reduced to 6-inches thick, which
     was capable of supporting the design load of  400  to 500 psf.

Reduce Ceiling Heights in Administration Building

     Tri the  original concept a  two story  administration building was provided.
     The distance from  the ground floor to the second Plooc  was  12 ft,  6-Inches
     and from the second floor to the roof,  was 11  ft,  6-inches.

     In the proposed concept the overall height  of the  building was reduced  by
     two feet, one foot on each  floor.  This reduction  was  accomplishable because
     the ceiling heights in the original design were greater than required for  an
     administrative building.

Reduce Size of Operations Building Basement

     In  the  original  concept,  the  operations building had  a  partial  basement
     which was used for a blower room, mechanical  room, electrical room and stor-
     age area. The first floor area  included two offices,  a conference  room,  and
     3600 sq ft of workshop and truck space.

     In the proposed concept, blower room  and storage area in the  basement  were
     reduced in size,  and  the first floor  workshop  and truck space were reduced
     to 2900 sq ft.

Reduce Building Size by Moving Bulk  Storage Tanks_Out side

     In the original concept  fiberglass storage tanks  were used  for bulk storage
    • of liquid polymer, ferric chloride,  and lime. All of  the bulk  storage tanks
     were located indoors.

                                                     BUILDINGS OR STRUCTURES
In the proposed  concept,  the chemical storage units were  located outside of
the building/ in an acea  accessible  to  trucks to facilitate truck delivery.

                                                         BUILDINGS OR  STRUCTURES
      l?iฎ_c-ฐntฎyฐ.r.s. -ฐy. Relocating Vacuum Filter Building
     In the original'concept,  both existing and new vacuum filters were used  for
     sludge  thickening.  Due  to space  limitations,  the new  vacuum filters were
     located in a new building,  which was not immediately adjacent to  the  exist-
                                                                existing  and
     ing  building.
                   Two  conveyors  were used  to  connect the
     The  proposed  concept  placed the  two  buildings  adjacent to  each  other,
     thereby  eliminating the conveyor belts  and using  a  common wall. Figure  42
    ' shows sketches of the  original and  proposed concepts.

Raise Tunnel  Elevation

     The  original  concept used tunnels which  were several  feet below grade.

     ThA  proposal  recommended raising the'tunnels,  making the top of  the tunnel
     at  ground elevation.  The tunnel top  would serve  as  the sidewalks  in  this

Relocate  Blower Building from Top of  Aeration Basins to Ground Surface

     The  original concept  located the  blower  building above  the  aeration tanks
     supported by  a  concrete beam and column  framing system.

     The  proposal recommended relocating the blower building to a location adja-
     cent to the  aeration basins. The new  location  would  place the building on a
     concrete slab directly on the  soil,  thereby providing  better  support than
     the  original concept.                    ,

 Place  Boilers Inside Existing Digester Control Building

     The initial design  to  upgrade a treatment facility included construction of
     a new boiler room beside existing  digesters.
      The  proposed  concept  suggested  placing  the new  boilers
                                                                  in the  present
     digester" control room to eliminate  the  construction cost of a new building.
     The proposed design only required  modification of the existing building and
     provided an additional benefit by reducing the amount of piping required.

Relocate Blowers to Aeration Tanks

     In the original  design  concept the blowers were housed  in  a portion of the
     power and generation building.  A. long run of  42-inch air pipe was  required
     between the blowers and the aeration building.

     The proposed concept recommended relocating the blowers  to  a separate blower
     building and  reducing the size of the  original  power/generation building.
     The new blower building would  be located adjacent to the aeration tanks and
     thus would eliminate a substantial  portion of  the 42-inch air piping.

                                      119                    ••'-.'

                                            BUILDINGS  OR STRUCTURES
  Figure 42.  Eliminate sludge conveyors.

                                                          BUILDINGS OR STRUCTURES
Relocate the Blower Building and Make a Common Wall with the Aeration Basin

     In the original  concept  the blower building was located above  the  aeration
     tanks supported by beam and column framing,  system.  A superstructure  with the
     same type of architecture as an adjacent building enclosed  the blowers.

     The proposed concept would relocate the blower building between two  aeration
     tanks, along with the  secondary sludge pump station,  thereby  using  the tank
     walls  as  common  walls and  masonry  walls  for   a  portion  of  the  building
     extending  above  the tanks.  The proposed  concept  also used  precast  double
     tees for the roof system.

Omit Gravity Thickened Sludge Holding Tank and Long Suction Lines/Add Pumps

     The original concept withdrew  6-8% sludge by gravity from sludge thickeners,
     and  then  stored the sludge  in a  sludge  holding tank.   A  thickened  sludge
     pumping station was located adjacent  to the sludge holding tank.

     Due tto the  length of the sludge lines between the thickeners and the holding
     tanks  it  appeared and. that clogging  would occur periodically.  The  proposed
     concept eliminated  the holding tank  and placed a thickened  sludge pumping
     station between every  two thickeners,  thus  eliminating  the  long suction
     lines. Sketches  of  the original  and  proposed concepts are shown in  Figure
     ~43~.   '      '    ;  •                      •      '.-.-.•;--      ..•:•  ,•'

                       BUILDINGS OR STRUCTURES



                                                         BUILDINGS  OR STRUCTURES
MATERIALS                        ,                                                :

Replace Cast-in-Place Roof with Precast Concrete Slabs

     The  original  design  concept  included  the  use  of  cast-in-place  reinforced
     concrete roof .for  a building which  housed  several facilities,  including  an
     open gravity thickener- tank.

     The  proposal  recommended using  a metal  roof  deck instead  of  the  cast-in-
     place concrete roof.          .

Use Precast Floor Slabs Instead of Cast-in-Place Concrete  Floors

     The  original design  called  for  the use of cast-in-place  reinforced concrete
     floor slabs for the  secondary treatment building.              V:

     The  proposed  concept   recommended   using . spandeck   floor   slabs  for  the

Change Cover Material on  Tanks                                        ...     • .   ;

     The  original concept included covered rectangular  tanks for  primary clarifi-
     cation  and  aeration.  The  original  covers   were  to  be  constructed  from
     fiberglass material.                                                        -:,

     The  proposed concept used precast, pre-stressed hollow-core  concrete slabs.

Eliminate Basement Waterproofing

     The  original concept used waterproofing for  the pump  station basement in the
     solids handling building, as well as a pumped underdrained system..-         ;

     The  proposed concept eliminates the basement  waterproofing because  it- was
     considered to be redundant with  the  pumped  underdrained system.
 Use  Pre-Engineered Lightweight Metal Building

      A concrete block building was  used  in the original design  for shop facili-
      ties  and engine-generator combinations.                                     f

      Use  of  a  pre-englneered  lightweight  metal  building  was proposed  as  a
  :    replacement for the concrete block building.

 Use  Steel  Frame Stairs Instead of Cast-in-Place Concrete

      Originally,  the  digester building  stairs were  designed  for  cast-in-place

      It was recommended that  steel  frame and precast concrete  stairs  be used in
      the digester building and pump drain pit.

                                                          BUILDINGS OR STRUCTURES
                                                          Floor Plans

Use One Single Building to House All Plant Equipment

     The original  plan had separate buildings  to house chlorine  feed  equipment,
     sludge handling  equipment,  plant  heating equipment, aeration  equipment,  and
     the administration and laboratory  facilities.

     It was  decided that the  construction  of a  single multipurpose building  to
     house  the  process equipment  was  not  only  cost effective,  but also  would
     improve the functionality of  the  facility. Laboratory and  office  space also
     could be incorporated into the building, if  desirable.

Layout Change for Sludge Dewatering Building

     A sludge dewatering building was  designed  with dewatering equipment  on  the
     upper floor, and  a truck  loading area below.  The loading area was  completely
     enclosed, and  required a  truck to  back into  the building for  loading.

     An open drive-through truck loading facility was proposed.  The drive-through
     capability would  eliminate the need for  sludge  trucks  to back into the load-
     ing area, resulting in overall ease of operating the sludge hauling plan.

Reduce Chlorine Building Size

     Original design placed for  the  chlorine  feed and storage in  the same  build-
     ing. Heating of the chlorine building was required about 200  days  per  year.

     The proposed  concept  recommended  using outdoor storage  for  most of  the
     on-site chlorine  storage, reducing  the  building size  by approximately 50%.
     Savings from this revision were in  the building and the  monorail crane.

Eliminate Covered Vehicle Storage Area

     For a  plant  located in a southern climate,  the original design provided  a
     covered vehicle storage area.

     Elimination of the covered the vehicle storage  area was  proposed.

Redesign Control Building to One Level

     A  two-story  control  building  was  the  initial  concept,  with  about  5,000
     square feet on the  second story.  The second story  contained  a large display
     area, a conference  room,  a restroom and several hallways,  as well  as  other

     The proposal   recommended eliminating the  second  story,  and increase  the
     first floor  area by 2700 square  feet.  The proposal resulted in  an overall
     reduction of about 2300 square feet.

                                                         BUILDINGS  OR STRUCTURES
                                                         Floor Plans
                        .  .       .  --%.       . .If. I .  •
Reorganize Floor Plan and Placement of Equipment
     In  the original  concept the  solids treatment  building  was  arranged  into
     three  levels.  In the basement were  the  lower access  to the  incinerators,
     heat treatment reactors  and storage space. On the first  floor  were  offices,
     electrical  switch  gear,  laboratory,  restroom  facilities, lunch  and  confer-
     ence  room,   vacuum  filters,   vacuum pumps  and  accessory  equipment,  heat
     exchangers  and upper access  to the  incinerators  and  heat  treatment reactors.
     Conveyor belts from each vacuum filter  approach  a main  conveyor belt running
     across the  first floor at a 90ฐ  angle to  the  main conveyor belt. The control
     room  with   motor  control centers  and  instrument panels  was  located on  a
     mezzanine level above the first  floor.

     In  the proposed  concept, all  first  floor facilities were compressed into a
     smaller  area,  and multipurpose  rooms were established.  The vacuum  filters
     wererotated  90  degrees  to  discharge   directly  onto  the  main  conveyor
 :    directly and accessory equipment was relocated closer to  the vacuum filters.
     The motor control  centers  were relocated  to the  electrical  switch gear room
     on  the first floor,  reducing the  space   required in the .mezzanine  control
     room.              •...-'

 Eliminate Housing for HVAC Equipment

     A  major  interceptor pumping station had a superstructure  which was  56 ft
     above  ground level.  The  top two floors  of the superstructure housed heating,
     ventilating, and  air conditioning equipment.

     The proposed concept recommended eliminating the top  two  floors,   reducing
     the overall height of the  superstructure  from 56  ft to 30 ft*  In the propo-
     sal,  the  HVAC  equipment  would be mounted  on  the  roof  of   the  pumping

 Reduce  Volume of Building or  Eliminate Building

     In the original  design,  many areas of the treatment plant were  covered,  such
     as the headwords,  the grit  channels, dissolved  air  flotation units, and  the
     post-chlorination/dechlorination areas. All of these areas required  ventila-
     tion and for most, odor scrubbing was  also required. In  the headworks area,
     a  rather substantial loft was utilized to house a traveling bridge crane.

     A   review  of the  housing  needs for the  various  facilities  revealed  that
     reduction  or elimination of the building  requirements  for the  grit channels,
     dissolved  air  flotation  and  units  and  post-chlorination/dechlorination
     basins was  justified.  Housing  of  the  headworks  was  still  recommended,  but
     elimination of the  loft and  the  traveling bridge  crane was  proposed since
     portable cranes could be used for the periodic  removal  of  equipment in  the
     headworks  area.

                                                         BUILDINGS OR  STRUCTURES
                                                         Floor Plans
Eliminate Housing of Exhaust Heat Recovery Muffler System

     A two-story  building was planned to house  an  engine/generator combination
     and an exhaust heat  recovery muffler system. The engine/generator was to be
     on the  ground floor, and  the  exhaust heat  recovery  muffler  system on the
     second floor.

     Elimination  of  the  second  floor was  recommended as  there  was no  need to
     house the exhaust heat recovery muffler system.

Modify Control Building to Reduce Footage

     Originally the control building was  designed as  a two-story  structure with  a
     total gross  area  of 5,000 sq  ft.  The  ground floor covered  2,900  sq ft and
     the second floor covered 2,100 sq ft.

     The proposed concept suggested modifying the control  building into a  one-
     story building  and eliminating some of  the duplicate  spaces. By combining
     the entrance and reception area,  eliminating duplicate  restrooms and combin-
     ing the lab  office with  the  laboratory,  and  reducing  the  building  to  a
     single story, the space requirements were reduced to 3,600 sq  ft.

Reorganize Maintenance Building

     The  maintenance  building  as  originally designed  was  3,600  sq  ft.  The
     building included enclosed garages for parked vehicles  and equipment.

     The proposed concept  recommended  reducing the amount of heated space in the
     maintenance  building. By  reducing the total square footage  to 3,000 sq ft.
     The vehicles would be in a covered area with open sides.

Eliminate Administration Building  Basement,  Move Proposed  Improvement to First
Story Level

     The original design constructed an  administration building  with a  basement
     of 3,700 sq ft consisting of a boiler  room and shop serviced  by an  elevator
     and two stairs.

     The proposed concept recommended eliminating the basement,  relocating the
     boiler  room  to the  first  floor   level and  relocating  the shop to a garage

                                                          BUILDINGS OR STRUCTURES
                                                          Type  of  Construction

Use Gratings Over Effluent Troughs  _.,''..                 ,

     The original  concept used a reinforced concrete slab  for  the cover  to  the
     raw wastewater'screw pump.                                 '-.',-•..'-

     The  proposed  concept  simplified  construction by  substituting  grating  and
     handrails over the  screw pump.                    ..-,...'''

Eliminate Walkway Enclosure

     In-the original  concept a 35 foot'long walkway  connected two buildings.  The
     walkway was enclosed with  masonry walls and a concrete roof.

     In  the  proposed concept,  the  masonry walls  and  the concrete  roof  over  the
     walkway were  eliminated.             ,

Redesign Walls of  Sludge Facility Building

     The  original  design consisted of six anaerobic digesters connected through  a
     center core  support building.  The center core building was a multilevel con-
     crete frame  building with a steel frame roof system covered with 2-3/4" lift
     weight  concrete plank which was  then  covered with  insulation fill concrete.
     walls of  the  building were masonry.

     The  proposed recommended concept  reducing  the weight of the roof section by
     using metal decks,  rigid insulation,  achieving roof pitch  by tapering the ^
     insulation  or  sloping the  structural  steel and  using  cantilevered beams
     where possible. For the exterior wall, the proposed concept recommended use
     of utility  brick (JUMBO)  and reducing  the  thickness of backup  blocks.  It was
     further recommended that the parapet  and limestone coping at the top  of the
     building be eliminated in favor of a gravel  stop.          •

 Eliminate Superstructure of Return Sludge Pump  Station

     A return sludge pumping installation  utilized  a wet well-dry well  concept.
      Pumps were  located in the  dry well,  but  were  driven by  motors which were
      located in a building above the  dry well.

      The proposal  was  for elimination of  the  building enclosing the motors.  An
      equipment hatch was used for access through  the  slab  and into  the  dry well.

 Delete Tile Floors and Tile Walls of  Main Pumping Station

      The original  concept  included quarry  tile floors  and ceramic tile  walls  in
      the influent pumping station.

      Use  of  quarry  tile  and  ceramic  tile  was  proposed to  be deleted,  with  the
      concrete walls  and  floors being  left  in  their natural form.

                                                         BUILDINGS OR  STRUCTURES
                                                         Type of Construction
Use Pre-Englneered Building

     Originally, dissolved air flotation sludge thickeners were  to be housed  in a
     building specifically designed and constructed for that purpose.

     The proposal recommended using of a pre-engineered building of  approximately
     the same dimensions.

Use Insulated Steel Building Instead of Concrete Block

     The  original  design  called for  a blower  building with  wall  construction
     using a concrete block with a brick veneer.

     The proposal recommended a steel-frame, insulated metal panel building.

Use Reinforced Concrete Pipe for Tunnels

     The original design used cast-in-place reinforced concrete  tunnels.

     The proposed design is to construct the tunnels  from precast reinforced  con-
     crete pipe. Figure 44 shows sketches of original and proposed concepts.

Use Pressure Relief Valves to Prevent Uplift in Chlorine Contact Tanks

     The  original  concept  used piles  to  resist  uplift  in  a  chlorine  contact

     The proposed  concept  utilizes  pressure relief valves  to relieve the  uplift
     pressures in lieu of hold down piles.

Revised Structural Framing

     The  original  concept  was a  building  constructed of  structural steel,  beam
     and column with exterior masonry wall of nonload bearing masonry. Columns at
     the building  exterior  carry a ten ton  crane.  The roof  consists  of a three
     inch metal decking overlayed by insulation.

     The proposed  concept  would be walls converted  to a  load  bearing wall. The
     ten ton crane would be carried by reinforced pilasters or  solid brick  piers.
     The  roof  system would be  changed to a  16-inch  or 32-inch double  tee  pre-
     stressed,  precast  concrete overlayed  by the  same insulation  and built-up
     roofing.  Flanges  of 32-inch tee  were  increased  to  four  inch  thickness to
     provide more corrosion resistance and higher compressive strength.

Insulated Steel in Place of Precast Panels for Building Walls
     The original  concept proposed  for the  administration building,  precast  con-
     crete panels  backed by 2-inch  rigid insulation with  6-inch concrete block
     between the insulation and the concrete panels.

     The proposed concept would substitute metal panels for the  precast  concrete,
     with no change  in  the  rigid insulation or the block  wall. The  metal  panels


                                               BUILDINGS OR STRUCTURES

                                               Type of Construction
                                        v-GROUND SURFACE
                   ORIGINAL CONCEPT
                    PROPOSED CONCEPT
        • CAST IN PLACE

                                         y~GROUND SURFACE
                                         PRECAST RCCP TUNNEL
Figure 44.   Use reinforced concrete pipe for tunnels.

                                                          BUILDINGS  OR STRUCTURES
                                                          Type  of  Construction
     would be insulated  and then attached using  girts  to fasten to  the  concrete
     block wall. Figure 45  shows  sketches  of  the  original and  proposed concepts.

Substitute Decorative Concrete Block  in  Place of  Precast  Concrete Panels

     The original concept proposed precast concrete  panels backed by 2-inch rigid
     insulation with 6-inch  concrete  block on the interior wall.

     The proposed concept would  utilize  concrete block with a 6-inch deep ribbed
     pattern and  a special  color in place  of the  precast concrete panels.  The
     exterior  block would  use reinforcing  in  the  cavities  of  the block.  The
     2-inch  rigid insulation  would  be  deleted,  but  the  original   6-inch  block
     would be retained.

Substitute Acoustic Metal Panel for "Sound Blox"

     The original  concept  proposed  to  construct the  blower  building utilizing
     "sound blox" for the walls in order to  reduce the  transfer of noise  from the
     blowers to the outside  area.

     The proposed  concept eliminated the "sound  blox"  in area  of  the  building
     where acoustical  metal panels  were  used on the  outside  of the building.
     Figure 46 shows sketches of  the  original and proposed concepts.

Use Fiberglass Covers Over Tertiary Filters

     The tertiary filters  in the original concept had  a  superstructure  over the
     entire filter area.

     In  the  proposed concept,  the superstructure would  be  eliminated  and  sub-
     stituted with  a movable fiberglass  arch cover  sized to  fit over any one of
     the filters.  The  cover would allow work to  be done on  a filter when  it is
     out of  service. The  cover  would  be a  fiberglass  arch  mounted on  rollers
     which would roll on an aluminum  track from one filter to another. Figure 47
     shows a sketch of the proposed concept.

Substitute Aluminum Geodesic Dome for Concrete Dome

     The original concept proposed using precast  concrete domes to cover  the pri-
     mary sludge thickeners, gravity  thickeners,  and sludge decant tanks.

     The proposed concept  would  substitute  aluminum  frame  geodesic domes  with
     aluminum panels  for the  precast concrete domes.  Aluminum domes are light-
     weight and can  be  erected as a  unit  in  three to  five weeks. Perimeter ten-
     sion is not  transferred to  the  concrete  tank. Openings  for skylights,  air
     intakes, or exhaust can be easily inserted as required.

                          BUILDINGS OR STRUCTURES

                          Type of  Construction




                                         . W






                                                      BUILDINGS OR STRUCTURES
                                                      Type of Construction
                      METAL PANEL
                    METAL PANEL
Figure 46.  Substitute acoustic metal panel  for  "Sound Blox".

                                            BUILDINGS OR STRUCTURES
                                            Type of Construction
A .

i I !
i i 1
.* a
— 1 ^

- '\j U


                 ORIGINAL CONCEPT
                  PROPOSED CONCEPT
Figure 47.   Use fiberglass covers over tertiary filters.

                                                          BUILDINGS OR STRUCTURES
                                                          Type of Construction
 Use  a  Ladder  and  Safety  Cage  for Access  to  Roughing  Towers  in  Place  of
 Cantilevered Walkway

     In   the  original  concept  roughing  towers   had   a  cantilevered  walkway
     completely  around  the  90  ft  diameter  towers.   This   concept  required
     structural support for the  concrete  walkway and aluminum  handrail,  as well
     as an aluminum  access  stairway  and  handrail.

     In the  proposed concept  the walkway around  the  towers was  eliminated,  and
     access  to the  top of the  tower would be  provided  by  a  ladder  and  safety

 Use Precast  Tilt-Up  Structure  in Place of  Cast-In-Place  Concrete Structure

     The  original  concept proposed a 3-story  cast-in-place concrete structure for
     the  main  control building.

     In the  proposed concept, the building would be  single story  slab on-grade
     building.  The walls would  be precast concrete  (tilt-up  type) and  the roof
     would also be  a precast  concrete  element.  Additionally,   equipment  founda-
     tions would be  cast independent of  the rest of  the  building.

Change Sidewall Construction on  Oxidation  Towers

     Oxidation  towers using plastic  matrix media were  to be  used for carbonaceous
     BOD  removal  prior to an  aeration basin.  Precast concrete  walls were  to  be
     used for sidewall  construction  of the towers.

     The proposed  concept  recommended using fiberglass walls instead of the con-
     crete walls.

Eliminate Parapet

     A 3  ft high  parapet was  used   around  a building  to  visually shield  HVAC
     equipment  located  on the  building roof and to act as  a  guardrail for mainte-
     nance personnel working on  the  roof.

     Removal of the  parapet was  recommended, and  use  of portable  guardrails was
     recommended when roof mounted equipment was serviced.

Reduce Windows in Digester Control Building and Dechlorination Building

     The original  window arrangement  required heavy wall  reinforcement in  order
     to transfer seismic loads from  the  roof  to the wall  below the windows. The
     windows in the  dechlorination building were  located  such  that little  light
     was admitted and building appearance was only slightly enhanced.

     The  proposed concept  recommended  eliminating or  reducing  the  number of
     windows in the digester control  and dechlorination  buildings,  and  using sky-
     lights to improve natural light.

                                                         BUILDINGS OR  STRUCTURES
                                                         Type of Construction
Build Sunscreen Over Chlorine Cylinders Instead of Enclosing

     In  the  original  design,  the  chlorine  cylinders were  to  be  stored. in  a
     completely enclosed structure.                                     .   .

     It was  recommended that only a sunscreen  roof with  open  side walls  be  used
     instead of a totally enclosed structure.  '

                                                          BUILDINGS  OR STRUCTURES

Eliminate Elevator

     The original concept provided an elevator to operate between  the  main  floor
     and the pump room floor,  a  distance of about 17 feet. The  elevator  would be
     used only for personnel transport.

     The proposed concept was  to eliminate  the  elevator.

Use a Reduced Capacity Crane

     The original  concept  called  for  a  10  ton capacity  motorized crane to  move
     equipment in a pump room.

     After checking the  weights  of the  pump  room items,  it was  recommended  that
     the crane capacity be reduced.

Eliminate Traveling Bridge Crane in Blower  Building

     A building supported traveling bridge  crane  was  used in  the blower building,
     providing  the  capability  of  removing  any of  the  motors,  blowers,   and
     engines.  The crane  would  have  a   capacity of  7.5 tons,  which  would  be
     sufficient to remove an engine completely.

     The proposal eliminating the traveling bridge  crane,  and  using  a  mobile
     crane with  a 5  ton capacity. This  concept  would  require  that an  engine be
     disassembled if it had to be  removed from the blower building.

Eliminate Covered Parking From the Maintenance Building

     The  original design  used  a  precast  core  slab  roof over the  maintenance
     building's parking and parts  storage areas.
     The proposed  concept  recommended eliminating the roof over  the  parking  area
     and over the open parts storage  area.

                                                   ELECTRICAL, HVAC  AND  CONTROLS
                                                   Power Distribution
                                    ''CHAPTER 6 *•"
                          ELECTRICAL, HVAC AND  CONTROLS

Substitute PVC Conduit for Rigid Steel Conduit

     The  original  design  included rigid  galvanized steel  conduit encased  in  a
     concrete  envelope to  distribute electricity  to the  various  points  of  use
     throughout the plant*   •                                    "           ,

     It was recommended to substitute PVC  conduit for the rigid steel type in the
     duct banks provided  for  the electrical  distribution system.  The PVC conduit
     would be  of  the  type designed to be  encased in concrete.  Although the PVC
     does  not  have the resistance  to crushing  that galvanized conduit  has,  the
     concrete  encasement  would give the necessary physical  protection to prevent

Use Lower kV Insulated Cable:

     In the  original  concept 15 kV insulated cable  was used  for  4800 volt power
     feeders.                                                  ,

     In the  proposed concept,  8 kV insulated cable  would be used  for 4800 volt
     power feeders.                                           ,

Reduce Number  of Transformers at One Location

     In one  building,  four separate transformers were used, each connected  to the
     same 4160 volt  system.

     Consolidation into two  transformers  was proposed,  along with conversion of
     the  substation to a double-ended substation (connected to two separate 4160
     volt systems).   The change  would  decrease initial  capital  costs  slightly,
     eliminate  "common-mode  failure",   and .  provide   increased   operational

Use Oil Filled Pad .Mounted Transformers

     The  original  system used 480  volt  distribution  transformers,  4160 volt-
     480Y/277  volt,  500 kVA, 3 phase 60 hertz dry indoor  type*  The  efficiency for
     the  dry type transformers is 97%.                                  - -•

     The  proposed  concept  recommended  using  oil  filled,  outdoor,  transformers
     have an efficiency of 99% which results in  operating cost  savings as  well as
      initial cost savings.

                                                   ELECTRICAL, HVAC AND  CONTROLS
                                                   Power Distribution
Cable Trays for Routing 15 KV Cable

     Conventional  rigid  galvanized  conduit  was  used  for 15  kV cable,  although
     cable trays were  used  for  480 volt power  cable  and 120 volt control  cable,
     in the original design.

     The  proposed  concept  recommended using  PVC  jacketed,  corrugated  metallic
     sheathed cable for cable tray installation.

Substitute 480 Volt In-plant Electrical Distribution System  for  4160V System

     The  original  design  utilized a 4160v  "in-plant"  distribution system.  There
     was  an  incoming service switch  gear  lineup and  3  double-ended  load  center
     unit substations  arranged  for both primary  and secondary selective  service.
     These substations were to  be  double-ended  units with the  transformers  having
     a dual primary  rating  of 4160V and 13.2 kV. New feeders in  new underground
     ducts were  proposed  on the assumption  that existing spare  ducts were  in  a
     distressed  condition.  A second primary voltage of  13.2 kV was  provided for
     future use.

     A review of the total plant load  after  the proposed treatment plant  addition
     revealed that the load would be too small  for a 4160V system.  The  proposal
     recommended a 480 volt secondary selective  distribution system  using  exist-
     ing  spare  ducts  to  maximum capability on  the assumption  that  they  are  in
     usable  condition. A standby  diesel generator was  relocated closer  to  the
     4160V entrance to the plant,  to reduce  required  distribution  facilities.

Replace Circuit Breakers with Fused  Interrupter Switches

     Originally,  15  kV power  air  circuit  breakers were  used  for primary power
     distribution  switchgear.

     Fused interrupter switches were proposed  as a substitute.

Modify Primary and Secondary  Distribution Concepts

     In  the  original  design,  primary electrical distribution  was a dual-radial
     system with intermediate pad-mounted switching units. Secondary distribution
     was  from outdoor power  panels,  with  automatic switching through dual auto-
     matic transfer  switches  on the  transformer secondarys.

     The  proposed  concept recommended using a dual-loop system with sectionalized
     switch  and  fused primary  selector  switch. Primary  feed would be to double-
     ended substations with secondary distribution at 480 V, 3  phase, 4W.   Auto-
     matic tie breakers would be used on the 480 V system to provide uninterrupt-
     able power.

Material  Change  for  Electrical  Conduits

     Conduit used for branch circuits and  feeder circuits was  galvanized rigid
     steel conduit in  the original design.

                                                    ELECTRICAL, HVAC AND CONTROLS
                                                    Power Distribution
     The proposed concept recommended  replacing the galvanized  rigid  steel con-
     duit  with Intermediate  Metallic  Conduit  (IMC),  which  is  accepted  by the
     National  Electric Code.          ,  .        •'.'....-'•         ;

Use Load Interrupter  Switches  With Current Limiting Fuses

     The original  concept proposes to use 4.16 kV air circuit breakers.

     The  proposed concept uses 4.16 kV load  interrupter switches  with current
     limiting  fuses.                                                              •

Reduce Size  of Feeder Cables MCC's

     The  original concept  used parallel  500  MCM  feeders  for 'two 'motor control'
. .-   centers.  These  feeders had  an ampacity of  760 A. The 'transformer would  be
     rated at  300 VA  with a full  load current of 360 A.   .

     The proposed concept would reduce the feeders  to  the  motor control centers
     to parallel  250  MCM feeders,  with  an ampacity of 510 A. The voltage drop for
     this proposal would not  exceed 1%  of the rated system voltage.

Use Full Voltage  Across  the Line Starters              ..........    .  ,,,,.,.,,

     The  original concept  used 7200 volt, reduced .voltage,  primary reactor type
     starters  for 2500 hp blower motors.               •  .

     The  proposed concept would  use  less complicated  7200  volt  full voltage,
     across  the  line starters. The utility  company permits  starting  of 2500  hp'
     motors  across the  line..                     ';   '                "-

General Power  Distribution System Modification

     The  original concept provided two 15 kV breakers,  four new  load centers, one
     new  5  kV  switch lineup,^and the one line  diagram  shows 4.8  kV r.adial  feed  to
     each, load center,  and one 4.8 kV  feeder to  each pair of  blowers.     '

     In  the proposed concept,   two  15 kV breakers and one 750  kV.load center would
     be  deleted.  The proposed  one  line diagram calls for a 4.8 kV radial  feed  to
     a group of two load centers and a 4.5 kV  feeder to. each  blower  and then ties
     a 480  volt secondary off-load center. The  proposed power distribution system
     .retains the same reliability as the original  system.        ,
 Change in Conduit Material for Underground Distribution  System

      The original  concept used a four-wire  arrangement for distribution  of  4160
      voltage . The underground  system was steel conduit in concrete,  with  a mini-
      mum conduit size of  3/4-inch

      The  proposed  concept recommended using  a  delta  three-wire  arrangement,
      rather than the four-wire arrangement,  and reducing the minimum conduit size
      from 3/4-inch to 1/2-inch.                         .                         -

                                                   ELECTRICAL,  HVAC AND  CONTROLS
                                                   Power Distribution
     Use  of  fiber  conduit  in  concrete  was  also  recommended  in-lieu  of  the
     proposed steel conduit in concrete.

Use Intermediate Metallic Conduit in Place of Steel Conduit

     In  the proposed  concept rigid  steel conduit  was utilized  throughout  the
     plant for the electrical wiring.

     In the proposed concept intermediate metallic conduit would be  substituted.

Use Owner Provided Transformer

     In  the original  concept  a 23,000-2400/4160V  transformer was  supplied  and
     connected by the electrical utility company.

     In  the proposed  concept the owner would supply,  install,  and maintain  the

Use Intermediate Metal Conduit in Place of Rigid Galvanized  Steel  Conduit

     The  original concept  specified rigid  galvanized  steel conduit  and,  100%
     redundancy for transformers throughout the project.

     The  proposed concept  suggested using  intermediate metal  conduit  for  all
     rigid  galvanized  steel  conduit. It was  also  suggested eliminating the  100%
     redundancy in the transformers.

Add Dual Primary Feed for Air Compressors

     A pure oxygen activated  sludge  plant  was planned to utilize  two 1000  HP  air
     compressors, served by  one motor  control center  and  a single  primary (4.16
     kv) feeder.

     The proposal recommended using individual motor controllers  for each  of  the
     air compressors/ and dual primary  feeders for each motor controller.  Overall
     reliability  of the  oxygen generation system would  increase from this  propo-
     sal although the initial  cost would increase.

Add Power Factor Correction Capacitors  to  10  HP or Greater Motors

     The original concept had  a low power  factor as  a  result of  using uncorrected
     squirrel cage induction motors.

     The proposed change would add power correction  capacitors of  sufficient kVAR
     to  all squirrel cage induction  motors of 10  HP and above to  provide  a mini-
     mum power factor  to be  0.95. Capacitors  would be  connected  at the  motors  and
     not in a single capacitor bank.

Reduce Standby Power Capacity

     The  original design contained provisions for a 600 kw standby generator to
     operate  during power failures.

                                                   ELECTRICAL,  HVAC  AND  CONTROLS
                                                   Power Distribution
     Receiving stream  quality required  an  EPA' 'Reliability .Class  II Plant  which
     requires generation  capacity sufficient to provide  treatment equivalent  to
     sedimentation and  disinfection.  Several of the  unit processes at  the  plant
     would  not  have to operate  a power  failure, which reduced  the  amount  of
     standby power required from  600 kw  to 200 kw.

Revise Specifications for 480v Motor Starters

     The original concept specified motor starters  having circuit  protectors with
     current limiters rated at 100,000 amps  interrupting  capacity.

     The proposed  concept would  delete the requirement  for  motor circuit  pro-
     teeters  with current  limiters  on  all 480   volt  motor  starters  and  use
     standard bus  bracing  with   combination circuit  breaker starters,, rated  at
     22,000 amps rms. The lower amp rating was determined thorugh  a closer analy-
     sis of the maximum fault current.

Use Aluminum Conductors Instead of Copper

     Copper  conductors  were  originally  specified  for  the MCC  power  feeder

     The proposed concept  recommended  using  750  (MCM)   aluminum conductors  in
     place  of the  500  MCM  copper, conductors, since  aluminum to  copper  termina-
     tions  could  be  specially designed  to  overcome  the  cold flow phenomenon  in
     thermal  expansion problems  associated with  aluminum.  Also,  the  aluminum
     could be oversized to accomplish  nearly equivalent  current  carrying capacity
     and nearly equivalent voltage drop  limitations.

                                                   ELECTRICAL,  HVAC  AND  CONTROLS

Delete Indicating Lights

     In the  original  concept the  instrument  main! control panel had  local/remote
     indicating lights provided for the motors with  local/remote switches.

     The proposed concept deletes  the  local/remote lights.

Eliminate Standby Computer

     The plant was  designed for computer  control  of major process functions.  In
     case  of failure of  the computer,  a standby computer was included in  the
     original design.

     Elimination of the second computer was proposed,  with  operation  of the  plant
     to be performed manually in the event of a  computer  malfunction.

Use Magnetic Flow Meters in Lieu of Parshall  Flume

     Under the original concept  the  plant effluent was metered using  an existing
     Parshall flume, after  the  flow  has passed  through on  existing chlorine con-
     tact chamber.

     In the proposed concept a magnetic flow  meter would  be installed in the dis-
     charge  of  the raw  wastewater pumps  to meter  the  influent  flow.  A bypass
     would  be constructed  around the existing chlorine contact  tanks and  the
     existing Parshall  flume.  This proposal  would provide a savings  in headless
     and reduce the head on the primary effluent pumps.

Eliminate Digester Gas Sampling System and Use a Laboratory Type Analysis

     The original  design  for  the anaerobic digesters  included  a methane sampling
     and analyzing system to measure digester gas methane content.

     The proposed concept  suggested  eliminating  the  sampling  system  and  using
     laboratory type analysis performed once every four  or  five hours to provide
     information on the quality and  methane  content  of the  digester gas since the
     original methane sampling  system was not reliable due to the high moisture
     content  of  the  digester  methane  off-gas.  A gas  analysis  apparatus  was
     already  specified  in  the  laboratory equipment and real time  analysis  of the
     methane  content was not necessary for process control.

Eliminate One Chlorine Residual Analyzer  and  Two Sulfur Dioxide Mixers

     In the  original  design,  two separate analyzers were used  for  sulfur dioxide
     feed  control  and final effluent  monitoring.  The  dechlorination  system also
     included two mechanical sulfur  dioxide mixers.

     It  was  recommended  that one chlorine  residual  analyzer  be eliminated  by
     alternating  the  function  of the  single analyzer  between sulfur  dioxide feed

                                                    ELECTRICAL,  HVAC.AND CONTROLS
                               .                              .
     control and. final  effluent monitorjrig. The turbulence  at  the  final  effluen^.
     weir  was  used  for sulfur dioxide  mixing and  eliminated  the  need  for  a
     mechanical mixer-                                          ...              :

Replace Magnetic Flow Meters with Sonic Flow Meters

     The original  design included the  use of 22  magnetic flow metering devices
     for all necessary process  streams.                   .-•-•'

     It was recommended that  sonic  flow meters be used in place of  the  magnetic
     flow meters.

Use Microprocessor Digital Controls at Local Control  Panels

     The original  design used  conventional analog controllers in  the  local con-
     trol  panels.  Analog  signals  were transmitted  to  the  computer  and central
     control  panel  for monitoring  only,  with  no  operator  remote  control  for

     The proposed concept  recommended using  microprocessor  based  digital  con-
     trollers in the  local panels  in place - of the electronic  analog controllers.
     Data  would be  transmitted to the. control building in  digitized  form  via
     coaxial cables.  The  proposed  digital data transmission  system  is less sus-
     ceptible to noise  and is more reliable.

Reduce Size of Central  Control  Panel

     The initial  design included a central control panel 30 feet  in length used
     to  display process variables  and  plant  status  using  a graphic  display,
     lights, and electronic indicators.

     The proposed  concept recommended reducing  the  size  of  the  panel to  5 feet
     and using  it  to, indicate  critical variable  and  annunciate critical alarms in
     case  the computer  system is down.  Cathode Ray Tube  displays would be relied
     upon  for graphic illustration of plant flow and  other noncritical data.

Use, Portable Sludge  Blanket Level Detector in Place  of Continuous Monitoring

     In  the  original concept,  continuous  monitoring of  the sludge blanket level
     in primary basins  was used as  an input to the primary  sludge  pump controls.
     In  the  proposed concept,  the  sludge blanket level control mode  was  elimi-
     nated and a portable  sludge level  detector  was provided.

Delete Rate Controllers in Final Tank Drain Lines

     In  the  original concept  rate controllers were provided for  the waste sludge
     lines from each final settling  tank. These  instruments  controlled  the rate
     of  tank underflow  from  the final tanks  to  return  sludge conduit. No pro-
     vision  was  made for monitoring or controlling  the rate of  sludge wasted to
     sludge  thickeners.      	

                                                    ELECTRICAL,  HVAC AND CONTROLS
     The proposed  concept deleted the  rate controllers on  the final tank  drain
     lines. Sludge underflow control would  be  by periodically opening and closing
     manual shutoff valves.

Eliminate "On-Off" Blower Operation for Dissolved  Oxygen Control

     The original  concept controlled  the dissolved oxygen  (DO)  in  the  aeration
     basin  by turning  the blowers  on and off as  required.  Also,  the  control
     scheme included a timer to override  the DO  system.

     The  proposed  control  scheme  recommended  that   the   DO  be  adjusted  by
     throttling the  air suction lines  to centrifugal  blowers. The blowers  would
     then run  continuously and avoid  excessive  wear and  tear on  equipment.  The
     two control schemes are shown in  Figure 48.

                                                  ELECTRICAL, HVAC & CONTROLS
                       ORIGINAL CONCEPT
                                  FLOW SIGNAL;  EQUALIZATION BASIN EFFLUENT

                       PROPOSED CONCEPT
                                                            BASIN NO,1
 Figure  48.  Dissolved oxygen control- system.

                                                   ELECTRICAL,  HVAC  AND  CONTROLS

Use Pneumatic Actuators Rather than Electrical  Actuators

     The original design  called  for  the use of electrical actuators  on 143  tele-
     scoping  return  activated  sludge  valves  at  the  secondary  sedimentation

     The  proposed  concept  recommended eliminating these  actuators  and  using
     pneumatic cylinder operators  with pneumatic controls.

Eliminate Analog Supervisory Control  Panel and Reduce Size of Main Control Room

     In the original  design concept,  the control room covered an approximate area
     32 feet by 35  feet and included  approximately 92 feet of control panel along
     the walls as well as a console  in the center of the room.

     The proposed  concept recommended using a computer based central control sta-
     tion.  This  would eliminate the  need  for an analog  type supervisory control
     ^gl.  space  would  be  provided  for about 20 feet of  computer  equipment,
     backup recorders,  multiplexers,   etc., and  the  control  room would be reduced
     in  size to approximately 20 feet  by 24 feet.  Figure  49 shows  sketches of
     original  and proposed concepts.

Eliminate  Return Activated Sludge Flow Pacing Controls

     Return sludge flow pacing controls were part of the original sludge handling

     It  was recommended that the return sludge flow pacing controls  be eliminated
     and manual  adjustment of return  sludge flow rate be provided instead.

 Reduce Number of Color Graphic Cathode Ray Tubes and Computer Printers

     A plant which utilized a computer for process  monitoring and control had two
      color graphic Cathode Ray  Tubes  in  the  control room and  a pjrinter in  both
      the control room and  the plant  superintendent's office.

      In the  control room,  use  of one black  and  white CRT and one  color  CRT,
      instead of two  color  CRT's was   proposed.  This change  would allow  the  color
      CRT to be used  for  graphic data and the  black and  white  CRT to  be used for
      tabular data and alarms. In  the event of failure of either CRT,  the  remain-
      ing one  could be used  for  all  purposes. Elimination of  the printer in the
      superintendent's  office was proposed,  since  all  reports  and  logs  could
      easily be printed in  the control room and delivered to  the  superintendent.

 Eliminate Computer Link  With City Hall

      A computer was  planned for process  monitoring and control of  the  treatment
      facility. A data link with city hall was also included to  allow administra-
      tive  officials  to obtain process and maintenance information,  as well  as to
      perform general data  processing.


                        ELECTRICAL, HVAC &  CONTROLS


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                                                   ELECTRICAL, HVAC AND  CONTROLS
     Elimination of the  data  link to city hall was  proposed.   This proposal  was
     based  partly  on  cost of  the  data  link, but  more  importantly,  due  to  a
     greater  chance  of  computer  failure  as  the  usage  for  data   processing
     increased. If such  a failure occurred when  the computer  was being used  for
     data processing by  city  hall,  it would  reduce  the  overall  reliability of  the
     treatment .facility.  A separate small business  computer was recommended  for
     city hall.

Delete Computer Control

     A  10.5 mgd,  2 stage  activated sludge  plant was  designed to be  completely
     controlled through  the use of  a computer and  a variety of  fixed  monitoring
     probes,  such  as D.O.,  suspended solids,  pH,  sludge blanket depth,  and liquid
     level.  The plant  could  be  operated manually in  the event  of   a  computer

     Elimination  of  the  computer and manual  and/or semi-automated operation of
     the plant  was proposed.  Portable probes  would be used instead of the fixed
     monitoring probes used with  the computer.

Change Pump Controls

     Pump  controls specified in  the original  design were simplex,  variable speed
     control  with  solid  state controller with wound rotor motors.

     In  order to  save electrical energy, the proposed  concept recommended using
     an  adjustable frequency drive system. The system would lend itself to future
     expansion  to the   triplex   mode  of operation  with minimal  future   cost

Use  Different Control  on Return Activated Sludge Pumps

     Originally,  the design  included eddy current  couplings for speed control  of
     return activated sludge pumps.

     Because the return activated sludge pumps  operated at low efficiencies,  the
     energy consumption  was  very high.  The proposed  concept  recommended using a
      single  large (125  kVA)  variable  frequency  parallel drive  for  all three
     pumps. The more efficient drives  would save energy and offset the high  cost
      of the drive system.

 Replace Sluice Gates With Slide  Gates

      In the  original  concept,  sluice  gates were  used  for  the  aeration  tank

      The  proposed concept recommended  replacing  the  sluice gates  with slide

                                                    ELECTRICAL,  HVAC AND CONTROLS
Use One Sluice Gate in Place of Two           lfe  -          ,.-.•'..

     Two parallel  sluice gates were  originally provided  to  control flow  in  the
     chlorine tank influent channel and  at  the  effluent  pump  station bypass.

     The proposed concept  recommended replacing each pair of sluice  gates  with a
     single gate of equal  total area.

Use Manually Operated Sluice Gates in  Place of  Motor Operated Sluice Gates

     The  original  concept  proposed motor  operated  sluice  gates  at each  screw
     pump. The function  of each gate  was to isolate an  individual  pump  for main-
     tenance and replacement.

     The proposed  concept  recommended manual slide  gates, since the gates  would
     not be operated frequently.

Change Specification for Gate Valves

     The original concept  specified gate valves for  sizes  2-1/2  inches  and  larger
     steam condensate and natural gas  piping.

     The proposed  concept  recommended  using  butterfly  valves  for  gate  valves
     greater than 2-1/2  inches.

Use a Single Weir in Place of a Double Weir

     The original  design for primary  settling  tanks includes an inboard,  double
     weir, cast-in-place concrete effluent  trough.                             ~~

     The  proposed  recommendation  was .to   utilize  an   outboard,   single  weir,
     cast-in-place concrete trough.

Use Fiberglass Trough in Place of Concrete

     The  original  concept  for  the  circular primary  clarifier  provided   an
     inboard, double weir, cast-in-place concrete effluent trough.

     The alternate  recommended was  to  use a  fiberglass  trough in  lieu of  the
     concrete.              -

Reduce Length of Splitter Weir

     The original  design  concept  included   8 ft  long splitter  weirs  in a flow
     splitting structure.

     In order  to  reduce the potential  for settling of  solids and to provide
     better low flow accuracy, the proposed concept  suggested reducing  the  length
     of the weirs to 4 ft.

                                                   ELECTRICAL, HVAC AND CONTROLS

Reduce Lighting Levels by 50%                      '••.'.

     The original  concept  utilized a combination  of fluorescent, mercury  vapor,
     and Incandescent lighting.

     The proposed  concept  recommended that the  lighting level be reduced  to  the
     levels  which  approach the General  Services Administration  Energy  Conserva-
     tion Design Guideline. The reduction  was  to be  accomplished  by  approximately
     a 50% reduction in foot candle levels, use  of high pressure  sodium or  multi-
     vapor for  high bay lighting, using  less  expensive fixtures or  changing  the
     types of fixtures,  and by using a  series lighting system for  site lighting
     at 2400 volts.

Delete Lighting on Perimeter Road

     Originally,  the plant perimeter road was  lit with  sodium lights  on  25'

     The proposal  was  to delete  these fixtures  on the plant  perimeter  road,  and
     to only light the  entrance road  and the  parking area.

General Use  of  High Pressure Sodium Lights

     In  the original  concept, mercury  vapor lights  are  used  in   high ceiling

     In  the  proposed concept, high pressure  sodium  lights  would be  used  in the
     high  ceiling  areas.  The  high lumen  output  of  high pressure  sodium  lights
     would require fewer fixtures and lower wattage for the same footcandle level

                                                     ELECTRICAL, HVAC AND CONTROLS
HVAC          '.   _                     7         •

Use an Amplified Heat Pump In Place of Electrical Resistance Heating for the  , ,,.,.
Building                                                       ...       .. - ,  .

      The original  concept uses electrical  resistance heating to,heat buildings.

   >.  In the,;piropo.sed concept an  amplified heat pump with  the  final effluent as a
 ...  ;heatr source was  substituted. The amplified heat pump  could •. be-  used as the
      main., source, fpr.heaMng the-buildings since it can concentrate the heat from
      the., final  plant effluent, ,to  a temperature of about 160ฐF.     '-,,-_-..

.Delete Pneumatic Steam Control Valves                                    ''.'.."•'""

      The original concept uses  pneumatic  steam control valves  for 'the main zone
      steam lines.                                                  .  '.     ........

      The iproposed concept would eliminate the pneumatic main  zone steam control
      valve and  manually close  the isolating valves  provided  to  shut  down the
      steam main.


                                                              On-Site Generation
                                    CHAPTER 7


Reduce Number of Standby Generators

     A plant had a total connected load of  1500 kw, with  900  kw  considered essen-
     tial  and 600 kw  nonessential.  Standby  generations  totaling 2250 kw (3 ,@
     750 kw)  were  planned  to be  installed.    One  of these  standby  generators
     served as a standby to the other two generators.

     The proposed  concept  recommended,  installing emergency  generation capacity
     for the essential load only. Two 900 kw  generators were  proposed.

Use Electric Cogeneration in Place of Flaring Excess Digester Gas

     In the  original  concept the digester  gas  was utilized  for gas engines  and
     prime mover equipment. Any gas  in excess of  these requirements  was flared as

     The proposed  concept  recommended  using excess  gas 'to  generate  electrical
     energy, with sale  of  this electrical  energy to  the power  company supplying
     the plant.

Produce Mechanical Energy With Excess Digester Gas
     Digester gas  was  planned to be  used for digester  heating,  with excess  gas
     used  in an engine/generator  combination to  produce  electrical  energy  for
     on-site  usage.  Cooling  water from  the  natural  gas  engine would  also  be
     available for digester heating.

     The proposed  concept recommended  using the  excess gas  in  an engine  which
     would directly drive other equipment,  rather  than  driving a  generator.

                                                                   Heat  Recovery

Use Digester Gas for Space Heating Boilers

     The  original  concept  used  purchased  natural  gas  to  fire  space  heating
     boilers, while the excess digester  gas  was  flared.

     In the proposed concept excess  digester gas would be used  to  fire  the  space
     heating boilers, with minimum purchases of  natural  gas.

Eliminate Engine Generators

     In the  initial  design,  two engine  generators were used to  convert digester
     gas to  electricity.  The generators  were housed  in  an energy .recovery build-
     ing which' had space  for an additional  future  generator. Plant space heating
     was accomplished using  natural  gas.

     The proposal  recommended eliminating the engine generators and using the gas
     from  the  digester for  space and process heating.  This  change  reduced the
     size  of  the  energy recovery   building significantly,  and  provided  more
     efficient  use  of  digester  gas since  conversion  to  heat  is  much  more
     efficient  than conversion to electricity.  The proposal eliminated  the need
     for purchased natural gas.

Eliminate Heat  Exchangers and Add Radiators

     In the  original  design, ebullient cooling  of  the  generator engines produced
     hot  water which  was  pumped  to  five  new   heat  exchangers  to  heat  the

     The proposed concept recommended eliminating the heat exchangers  and  using
     radiators  on  the  generator.

     The recommended change  added two new  boilers to produce  steam  for heating
     digesters. By installing  radiators, it was  possible  to  eliminate  the top
     floor of  the  maintenance building.

Install Heat Exchanger on Effluent Sludge Line

     The original  concept used anaerobic digestion for  a combined stream of pri-
     mary  sludge  and waste  activated sludge. Digester  heating  was  to  be  accom-
     plished by an existing one million Btu unit  and new units which are equiva-
     lent  to one  million Btu.  The new  units were staged with  a low temperature
     exchanger preceeding the high temperature unit.

     In  the proposed  concept  a  second  low-temperature exchanger was  added for
     preheating sludge.  This  heat  exchanger was  actually only a modification of
     the  digester influent  and  effluent piping,  in  which the  digester discharge
     would  be  passed  through  a 4"  pipe  located  concentrically  inside a pipe
     carrying  the digester  influent as   shown  in  Figure  50. The procedure  would
     allow  recovery of 50% of the heat in the digester discharge.


                                                                 Heat Recovery
                                          RECYCLE LINE-
                               HEAT INPUT
                                                       SINGLE STAGE
                                                       ANAEROBIC   .
                          ORIGINAL CONCEPT
                                              RECYCLE LINE-
                          AUXILIARY HEAT
                                            SINGLE STAGE
                                ^DIGESTED SLUDGE
                           PROPOSED CONCEPT
      Figure 50.   Install heat exchanger on effluent sludge line.

                                                                    Conse rvation

Rotate Administration Building 90ฐ

     The  original design  showed the  administration/lab building  with the  long
     axis  in  a north/south direction. This  caused  the majority of the walls  and
     windows  to  have  an east/west exposure, resulting  in  significant  energy  cost
     to cool  the  building  during warm weather.

     The proposed concept  recommended rotating the building  so  that  the  majority
     of the windows face north and south in order  to  decrease  summertime cooling

Use Reflective Insulating  Glass  in the Administration Building

     The  glass in the  adminstration  building covered  is  about  15% of the  total
     area  on  2 sides of the building. The  original  design  concept  used regular
     plate glass for  these windows.

     The proposal suggested using reflective insulating glass in place of regular
     glass.   The  proposal   resulted   in  an  increased   initial  cost,   but  reduced
     cooling  and heating requirements over the life of the building.

Extended Pump Discharge Pipe Below Water Surface

     The  original design included an intermediate pumping station to  lift primary
     effluent to the aeration basins. The pumping station  consisted of  vertical
     turbine~pumps discharging into the  top of a channel.

     The  proposed design  extended the  discharge pipe  from  each pump below the
     water level in the channel. The effective pumping head was thereby reduced
     through   a  siphoning effect.  Figure  51  shows  the  original  and  proposed

                             SLUICE GATES
               FROM PRIMARIES
 <ฃ. PUMPS .
                                                     TO AERATION
                                                         ANTI-SIPHON VACUUM
                                                         RELIEF VALVE
                                         EL 239.0
                                                                      EL 233
                     PROPOSED CONCEPT
       Figure 51.  Extended pump discharge pipe below water  surface.


                                                                     Odor Control
                                    CHAPTER  8
Reverse Air Flow Through Trickling  Filters

     Since odor-control at  the  treatment facility was an important consideration,
     domed covers  over trickling filters  were included in  the  original concept.
     Scrubbers were planned to  remove and deodorize air which collected under the
     dome covering.

     Reversal of "normal"  air flow through the  trickling  filters was proposed  in
     conjunction with elimination  of the domes  over the trickling  filters. The
     scrubbers  used  in the original  concept would  be connected through air  ducts
   '.  to  the  under/flume  area   of- the  trickling  filter,  pulling  air downward
     through  the trickling filter  and then deodorizing it.  A localized deodorant
     system was proposed  for masking minor odors.

Revise Odor Control  System

     The  original  concept used  ozone for  odor control  of  air from  the headwords
     building,  where  odor  emanated  from  both  the  raw  wastewater  and  septage
     delivered  to  the plant. Since heating requirements for the  headworks  build-
     ing  were 34,000  CFM,  the  ozone deodorization  system was  sized for  34,0_0_0_
   -  CFM.

     In  the  proposed  concept,  the  headworks  was divided  into separate areas  for
     the  septage and sewage to  allow individual control of  odor  from each  source.
     This change  was  made because  over half the  odor  was attributed  to  the
     septage. In the proposal,  activated carbon was used to treat the  more   .con-
     centrated odor from  the  headworks  area,  with the system .sized  for J100 CFM,
     and only intermittent operation required.  The ozone  system for  the headworks,
     area was in turn reduced to 17,000 CFM,  as was  the heating system.

 Hydrogen Peroxide  Injection Into Wastewater Flow

     Odor control was  a key concern at  an existing  plant,  and  extensive measures
     were included  in the  original  design for  its control. The  key odor  control
     measures consisted of covering the major  process units and  using odor con-
      trol scrubbers for the air contents.

      Injection' •of^-nydr6
                                                                    Odor Control
     In the  proposed concept, in  the  low odor  potential  area, carbon  scrubbers
     were used instead of wet chemical scrubbers.

Eliminate Covers on Standby Aerobic Digesters

     In the  original concept, standby aerobic  digesters,  preaeration tanks,  and
     aerated grit tanks  all  had covers made from  aluminum panels.  Air was  to  be
     withdrawn from under the covers and  scrubbed  for  odor control.

     In the  proposed  concept,  no covers would be  used  on  the  standby  aerobic
     digesters, but  the  covers  were  retained on the preaeration and  aerated grit

Use Scrubbers Ahead of Carbon in High Odor Areas

     In the  original  concept,  activated carbon was  used  to scrub  air as  an odor
     control measure.

     In the proposed  concept, in  the  high odor potential  areas, the  air  would be
     pretreated using a,  chemical  scrubber ahead of  the ca.rbqn, thus  reducing the
     amount of activated carbon regeneration required.

Recycle Air Thru Aerated Channels  forOdor Control

     In the  original  concept,  odor control was  accomplished  by hydrogen peroxide
     addition  to  the plant  influent,  chemical  scrubbing of  air  from  under  the
     primary clarifier covers, and  aeration of the channel between  the  primary
     clarifiers and the  aeration  basins. Bight separate  chemical scrubbers were
     used for air from under  the aeration basin covers.

     The proposed concept recommended  using   the air collected  at  the  primary
     clarifiers as  suction air  for supply to the channel  blowers.

Eliminate Biological  Odor Reduction Tower and  Use  Two-Stage Carbon

     The original design included  a two-stage  odor removal scheme  employed at two
     locations:  1)  the  headworks  building  for treating  odors from  primary and
     headwork  facilities,  and 2)  energy  solids   building  for  treating  solids
     handling odors.  The scheme included  a biological odor removal tower followed
     by activated carbon adsorption with an inner  stage  blower for  driving air
     flow. The  biological odor control  tower   operated  by blowing foul  air into
     the bottom of  the tower, and spraying  secondary  effluent  on  the top surface
     of the  tower.

     The proposed concept recommended  utilizing the two-stage odor removal scheme
     in the  same  locations,  but eliminating  the biological stage.  The recommended
     design  therefore employed  a  two-stage activated carbon system (considered to
     be  more effective  and  reliable)  and  required  the  blower  capacity  to  be
     increased  proportional  to the  increased  system pressure drop.  Figure  52
     shows sketches of the  original  and proposed concepts.


                                                                 Odor Control




                                                                     Odor  Control
Delete Odor Control from Waste Activated Sludge Thickener

     The original odor  control  system included a counter  flow packed tower  uti-
     lizing  sodium hypochlorite  as  the  oxident. Two  gravity  thickeners  were
     arranged  such  that either thickener  could  be  used  as  the waste  activated
     sludge thickener and the other used as  the primary  sludge  thickener.

     The proposed  concept  recommended deleting the  odor control system from the
     WAS thickener, since offensive odors  are generally not  emitted  when  gravity
     thickening WAS. To  implement the proposed change,  it would be  necessary to
     install the odor control system on one thickener,  and using that  thickener
     for primary sludge.

                                                                    Noise Control
NOISE CONTROL         -                                          •..-.-.."   .

Use Sound Absorbing Enclosures to Trap Sound at  the  Source

     In the\original concept  the  blower building is clad  with sound  absorbing
     materials/ i.e.  "sound blox",  hung 'ceiling,  and perforated metal  panels  to
     reduce the noise level due to blowers and motors.
     In the proposed  concept,  blowers and motors  would be partially  enclosed in
     sound absorbing  enclosures which  trap  sound at  the source," and eliminates
     the need for other acoustical treatment.


Eliminate Brick Cover on Columns in Headworks

     The original concept provided a headworks building  with  26  interior columns.
     The columns are encased in concrete and faced with  brick.

     In the proposed concept the brick facing was eliminated  on  all 26 columns.

Delete Brick Paver on Ramp to Administration Building

     The  original  concept  for  the  administration  building indicated  a brick
     paver on  the ramp  for  the entrance to the  building as  well as the stairway
     and other outside entrance areas.

     The proposed concept would eliminate the pavers from the entrance ramp, out-
     side areas  of  the  building,  and on  the entrance  wall. Brick  on  the ramp
     would be hazardous to handicapped people.

Delete Rubbed Finish for Concrete

     The  original  concept  required  all  concrete surfaces   built  against forms
     which would normally be  exposed to  view, to be  given a rubbed finish after
     patching tieholes, voids, honeycombs, and broken  edges.

     The proposed concept  would eliminate the  final  rubbed  finish.   Within  the
     proposed  concept,  the  concrete  would be  finished  as above except that  the
     final rubbing would be deleted. This would  be a "smooth  form finish"  per  ACI
     301, "Suggested Specifications for Structural Concrete Buildings."

Delete Painting

     The  original  concept  painted most  of the  concrete floors, walls, ceilings
     and stairs.

     The proposed  concept  recommended eliminating  all  painting of interior  and
     submerged concrete.
Use Surface Treatment of Concrete Block in Place of Stone Facing

     The original concept used stone facing on concrete  block.

     The proposed concept would  eliminate  the stone facing and  surface treat  the
     concrete block to create a pleasing effect.

Epoxy Finish in Place of Glazed Block

     The  original concept  used  glazed  block  for  construction of  the  filter

     The proposed concept would  use  standard  block with  an epoxy finish.  The  new
     epoxy  finishes   should be  equal  to the   glazed  blocks  and  the  building
     joints would be sealed.


Use Textured Block in Place of Stone Veneer  •

     The original concept used stone veneer  over  construction block.

     The proposed concept  recommended a  textured block  in place  of the  stone

Delete Paint on .Floors                 •

     In  the  original concept, painted floors were  used in  the  headworks,  solid
     buildings,  filter  areas, garag'e,  chemical  buildings and pump station.

     In  the proposed concept  the  floor surfaces would not be painted.

Use Stainless  Steel  Instead of Aluminum

     The original concept  used aluminum  handrails around open process facilities.
     Since the proposed treatment facility was  near the ocean.

     Substitution of stainless  steel handrails  for  the  aluminum  handrails  was
     proposed. The  service life  was  estimated to  be  20 years  for  the stainless
     steel and 10 years for the  aluminum.

Use Fiberglass Handrail and Grating

     The original conpept  proposed aluminum handrail  around the aeration tanks,
     rapid mix  tank,  grit chamber,  screen  pumps,  in the  process  building,  and
     around  the sand filters.                            :~

     The proposed concept  substitutes fiberglass handrails in place of the alum-
     inum handrail and fiberglass grating in place of  aluminum  grating. (Adequate
     safeguards  for quality control  and  proper  pigmentation  to  prevent ultra-
     violet  radiation deterioration were to be provided.)

 Use Concrete Handrails

     The original design  of  the  treatment facility included anodized metal hand-
      rails outside  primary clarifier  basins,  aeration tanks, sludge  equalization
      area, and chlorine contact basins.

      The proposed  concept recommended  using a  concrete wall 4-inches thick and
      3-1/2 feet high in the  same areas.

                                                                   Noise Control

Use Sound Absorbing Enclosures to Trap Sound  at  the  Source

     In  the  original concept  the  blower .building is clad  with sound  absorbing
     materials,  i.e.  "sound blox",  hung  ceiling,  and perforated metal panels  to
     reduce the  noise level due to blowers  and motors.

     In  the proposed  concept,  blowers and  motors  would  be partially enclosed  in
     sound absorbing  enclosures which  trap sound at  the  source, and  eliminates
     the need for other acoustical treatment.

                                                               Structural Details
                                     CHAPTER 9
                                  " '  Jt?'J* " ' •- '    . -^         ' '  '•       -...'-.     .    - -

STRUCTURAL DETAILS                       .         "•••  ~ ./'•.,-•

Use Wall Strut System  in  Place  of Cantilever-Walls

     In  the  original concept,  four  second-stage aeration basins  were built with
     common  walls.  The interior walls were  designed battered  (tapered)  and the
     exterior walls were designed uhbattered. All walls  were built  in a canti-
     lever fashion  with reinforced concrete.                             , ' ,

     In  the proposed concept  all walls would be built unbattered with Compression
     struts  installed  at  the top of the walls for strength.  The  struts would be
     placed  at  30 foot intervals. Figure  53  shows  sketches  of .the  original and
     proposed concepts.

Eliminate Peripheral Concrete Walkway on Trickling Filters               .   .

     In  the  original design, the trickling  filter  wall .were  built  with double-
     tie, precast concrete  members set vertically in a circle capped by a poured-
     in-place concrete ring.  The concrete  ring would resist hoop tension from the
     ends  of the double-tee  members,  serve  as  a "*  ft  wide walkway  around the
     filter, compensate  for unevenness in the  top of  the  double tee members, and
     provide stiffness.                         ,

     The  proposal  recommended  redesigning  the filter .with a 26" wide concrete
     stiffening  ring around  3/4 of  the filter circumference,  and  the remaining
     1/4  of  the  circumference  a  36"  walkway with  handrail. The proposal  would
     reduce  costs  and still provide  solid  footing  around  1/4 of  the  filter
   "  periphery to manually  rotate the distributor arms.

Revised  Pile Specifications

     *The  original  concept  provided  pile  specifications  with a driving point on
     "H" piles,  load test for twice the required bearing capacity,  and twice the
     required uplift capacity.

     The  proposed  concept  recommended  revising the  requirements to  delete the
     driving points for  "H"  piles which have  cut  off elevations" below the fill
•' "'  "layer,'  and  'a  reduction iri • the 'test  uplift "capa'city 'to' 1-1/2 "times ; the
••.-  •    • -  	•	• • ••<•••	-•...•    	,-'~-  	 ,• ••-    .-.-..,..>.<	

Use  Common Wall  for First and Second-Stage Aeration Basin

     Originally,  the  first  and: second-stage  aeration basins  were  parallel, to
     each other,  but did  not use common wall construction.

     It  was  proposed  to  relocate the second  stage  adjacent  to the  first stage,
     and eliminate  one of the original walls.


                                Structural  Details





             *  J      t
             ^—'      =:ซ



                                                               Structural Details
Eliminate Fillets •  ••  •  •'        ...     ,   :. . , .  ., •. ,."'..     -
                                 . .   ->Si:.  r  •:;.•  • '^T .        . ., . -,      •    ...
     Aeration tanks were designed with  fillets  in  the  bottom sides and  ends of
     the basins.                                                .    .

     Elimination  of  these  fillets  was  proposed,  since  they  serve   no  useful
    , function.        -      :               !      .          ::

Simplify Concrete Form Work               ,   ,        ,  ' :.  .,  '

     In  the  original, design,  the activated sludge  tanks consisted  of concrete
     walls with haunches and corbels.                      ••••••

     The proposed  concept  recommended eliminating  the haunches and  corbels in
    " order to simplifv the  concrete work and reduce the initial cost.

Use Straight Walls  with Minimal  Fillets  in Place of Complex Slanted Walls in
Aeration Basins     •             •
     In the original  concept the aeration tank  Used  slanted walls which required
     complex and involved  forming.                                          •

     The proposed, concept would use  straight walls  with minimal  fillets  in the
     bottom corners between  walls  and floors.

                                                         Construction Sequencing

Eliminate Installation of Equipment for Future Design Flows

     The pretreatment  facilities included  raw  influent pumping  and grit tanks.
     These facilities were  sized for  the ultimate flow  rate which was twice  the
     initial design  flow rate. In addition,  process  equipment for  these  facili-
     ties  was  sized  to  provide  treatment for  the ultimate flow.  The   process
     equipment  included . raw  sewage  influent  pumps,   mechanically  cleaned  bar
     screens, and grit collectors.

     In the proposed  concept,  any equipment  not  required  for the initial design
     rate would be eliminated.

Relocate Operations and Laboratory Building and Thus Eliminate Temporary Housing

     In the  original concept  temporary laboratory  facilities and  offices  were
     required while  the  existing structure was  demolished and reconstruction on
     the same site.

     In the proposed  concept,  a new location was  chosen for construction of  the
     new facility,  thereby  eliminating  the temporary  operations laboratory  and
     plant control. After construction of  the new  facility the original structure
     would be utilized for  storage.

Build Primary Clarifiers Before Flow Equalization  Basin

     The original design  required flow equalization basins during Phase I of  the
     project. Primary clarifiers were to  be  constructed five years  later during
     Phase II.

     The proposed concept  recommended constructing the primary clarifiers during
     Phase I  and defer  the flow equalization  basins  to  Phase  II.  The   primary
     clarifier, would be used  to  equalize  flow between Phase  I and Phase II.

MATERIALS        ....                   ...4'	;.:.   ...        .; ,.      ,,         .  ,  .'.;..

Use  PVC  Pipe  for Polymer Piping in Place of Stainless Steel

      In  the original concept,, the polymer transport piping was  stainless  steel.

      In  the,.proposed concept, ,Pyc  pipe,.with solvent weld fittings would  be  sub-
      -stituted for polymer piping.                          .

Use  Steel  Framing'

      The original, concept  used cast-in-place  concrete  to be  used for floor  and
      roof  construction.

      The proposed  concept recommended  using  steel  framing with metal  decking.
      Figure 54 shows sketches of the original  and proposed concepts."        •

'Substitute Fiberglas Grating -for Aluminum Grating               ..'••-.

      Since the  treatment  facility was located in  a coastal  area with high, cor-
      rosion rates, the original design specified aluminum gratings.     ,

      Fiberglass gratings were  proposed;as  a substitute for the aluminum  grating.
      The fiberglass gratings  would be constructed of fire  resistant,  reinforced,
      polyester.  The  fiberglass, gratings  would  have  a  20-year life  versus  a
      10-year  life for the aluminum gratings.                       . ,            :
 Use Concrete-Lined Channel in Place of.Reinforced  Concrete Pressure Pipe for
 Outfall Line      .  ..  ' '".-•-.' ;• •  ."..   ; .  '"•'•"'                   ''.'.''."'
      The original concept proposed using a concrete pressure pipe for the outfall
      line.   '.  :•      ....,,•'.-.'•.'     .             ...--'    .-'-..        - •'

      The proposed concept.recommended a concrete lined channel  in place  of the
      pressure pipe.
 Use Corrugated Steel Pipe in Place of'Reinforced Concrete Pressue Pipe for
 Outfall Line
      The original concept proposed reinforced  concrete pressure pipe for the out-
      fall line.

      The proposed  concept recommended  corrugated steel pipe  as  an alternative.
      The pipe would be lined with a bituminous coating.

 Use Fly Ash as Fill for New Construction

      The original  concept used sand  and  gravel for  fill  in the  construction of
      the plant.

      The  proposed  concept suggested  using  fly  ash  from the  incinerator  ash
      lagoons in place of  sand and gravel.                                       ;  ..

                          1% COMPOSITE DECK 22 GA
Figure 54.  Use steel framing.

"Shotcrete" Fixed Cover on Anaerobic Digester

     The  original  concept  was  to  construct  a floating  cover  on  the primary
     digester to allow storage of digester gas.

     The proposed change would construct  a fixed,  insulated "shotcrete" cover. A
     sketch of the proposed'cover is shown in Figure 55.

Replace Concrete Flow Equalization Basins With Lined Earthen Basins

     The original design included flow equalization basins constructed of formed
     reinforced concrete.                                                  ~

     The  proposed  concept  suggested  constructing  the  basins  with  earthern
     embankments lined with gunite  applied over reinforced steel. An alternative
     to the first proposal was earthen embankments lined with "Hypalon".

                       ORIGINAL CONCEPT
                                               "FLOATING COVER
                     PROPOSED CONCEPT
Figure 55.  Use "Shotcrete"  fixed cover on anaerobic digester.

                                    CHAPTER 10



Modify Method of Construction                                          .-'"',

     In the original design, manholes for a 54 inch interceptor were either 8 ft
     diameter precast  units  or 9 ft  diameter mansonry units with  top and bottom
     concrete  slabs  and grouted  inverts. Standard  4  ft diameter  precast risers
     were to be used to extend from the  top slab  to  ground level.

     The  proposal  recommended using  tee-style manholes  consisting  of  a  12  ft
     length of the 54-inch sewer  pipe placed on end and  supported  on the 54-inch
     interceptor, with an  access slot'- (-18"• x 48")  cut  in the  top  of  the inter-
     ceptor 54-inch  pipe were proposed.  Standard 4  ft  diameter  precast risers
     grouted to  the  top of  the pipe  of the 54-inch  pipe standing  on  end would
     also be used.  A plain  concrete  mat beneath  the  section of pipe containing
     the manhole would be  required for  support.  Alignment changes  in the inter-
     ceptor would be  made  with a pipe bend  ahead or  behind the 12  ft  length of
     pipe containing the manhole.

Replace Cast-in-Place. Manhole  With  Precast Manhole

     In the original design, the  interceptor used  cast-in-place  manholes.

     The proposal recommended  substituting, precast manhole sections  for  cast-in-
     place manholes.

                                                             General Construction

Eliminate Alignment Holes for Control of Line and Grade

     The original design required alignment/grade check holes  along with pipeline

     The proposed  concept  recommended deleting the  requirement for check  holes.
     The construction of the holes would be optimal  for the  contractor.

                                               INTERCEPTOR SYSTEM PUMPING STATION
                                               Structure         ' '
                                    CHAPTER 11

STRUCTURE    .    .   /';r •....'•-.   r .. ../V  :•.. .":...           ••   : ;    '•..•••-''•

Change Roof Deck From Wood Truss  to Precast Concrete

     The original roof  deck  design consisted of wood trusses with a plywood roof
     deck and soffitt framing. One pumping station used metal roofing and another
     used asphalt shingles which  would  blend with  the  s.urrounding buildings.

     Precast  concrete  roof  decks  were proposed  because  of  their  lower  cost,
     longer life, ability ,of: supporting a  monorail hoist, and resistance to fire.
     The proposed decks would* be  covered with 2-inch of lightweight concrete fill
     and a 5-ply tar and gravel roof.
                                             ?         -
Change Design Method arid Use Grade 60 Reinforcing

     The original  design utilized the  "Alternate Design Method,"  also  known as
     working stress design, and Grade 40 reinforcing.

     The  proposed  concept  recommended  'that  the  structure   be  designed  for
     restricted crack width, which allowed.the use of higher flexural reinforcing
     stresses. Grade 60. steel would be  used in the proposed change.

Reduce Structure Size due to Piping Revisions

     In  the  original  design,   the pump  discharged to  the  bottom  of  a  common

   ;  The proposed concept recommended relocating the discharge  to the side of the
     common  header instead  of  the bottom. Although  there was  little overall
     savings in piping costs by the proposed change,  the pump  stations  would be
     several feet shorter in length  and width and the  overall  pump station depth
     would be decreased about two feet. The  depth was  significant because of the
     prevailing high groundwater  conditions.

                                               INTERCEPTOR SYSTEM PUMPING STATION
                                               Emergency Generator

Reduce Size of Emergency Generator

     The original  design sized a standby generator for ultimate pumping station
     capacity of three pumps.

     The proposed  concept  recommended reducing the generator capacity  to the two
     pumps which  would be required  initially since the  third  pump would  not  be
     required until about 40 years in the future.

                                               INTERCEPTOR SYSTEM PUMPING STATION

Piping Modifications

     The original design utilized  a  discharge  gate and check valves on each pump.
     On  the  force main  leaving the pumping station,  gear  'operated  gate  valves
     were used on each side of  the control  valve.       ":   '- " -     l     •

     The proposed concept recommended  using DeZurik  eccentric plug valves  as  a
     substitute  for  the gate  valve and  the  check  valve 'an;d  knife gate  valves
     rather than  the gear operated gate valves for isolation of the control valve
     on the effluent force main.

Use Force Main Instead of Gravity Interceptor

     Two gravity  interceptors  were  tributary  to  the plant's influent  raw  waste-
     water pumping station.  One interceptor had  a pumping station  some  distance

     A proposal was recommended increasing the pumping head  on the  upstream pump
     station and  converting  the interceptor to a force  main which would  convey
     flow directly to  the  plant headworks,  bypassing the on-site  raw  wastewater
     pumping station. The other interceptor still required an  on-site  raw  waste-
     water pumping station, but the  pumping station was  now  considerably smaller
     in  capacity. Figure  56  shows  a  schematic  of  the original  and  proposed

                                          INTERCEPTOR SYSTEM PUMPING STATION
                        ORIGINAL CONCEPT
                         FORCE MAIN
                                                     TO BAR
                       PROPOSED CONCEPT
Figure 56.  Use force main instead of gravity interceptor.

                                               INTERCEPTOR SYSTEM PUMPING STATION
                                               Design  Concept

Replace Electric Motors with Diesel Drive                 ,       .  .     •

     A pumping station was  required  during  periods of  heavy precipitation,  to
     pump  flows  which exceeded the treatment  facility  capacity  into a  storage
     pond  for  subsequent  treatment. The pumping  station - would be utilized about
     _3_% of the time.  The original  concept  used 4  (1  as  standby)  pumps,  each
   '  driven by an  induction  motor and  each  having on-off control. Diesel engine
     generator sets were planned  for power generation for the electric motors,  as
     well  as for plant standby  power requirements.

     The  proposal  was  to  eliminate  the  induction motors  and  utilize  diesel
     engines to  drive the pumps  directly.  The standby pump was  eliminated,  and
     only  3 pumps  were  used  in the proposed  design.  The diesel engine on one  of
     the pumps was also  proposed to  drive  a standby  generator  for  other plant


                                                                OCEAN OUTFALL
                                                                Covering Material
              .•"'.'.'.'.   -   •.    CHAPTER, 12

                     .     •'••'-  OCEAN OUTFALL         '      .        .


Eliminate "Armor Rock" Covering

   •  In the  original design, a 36-inch ocean  outfall  was covered  with  a 5-inch
     thickness of  "Hevicote"and then to be further  covered  by 9-inch to 12-inch
     rocks. Then,  a  several foot thick layer of "Armor  Rock"  was to be added for
     additional weight  and protection.  The, top of the  "Armor Rock" was  to  be 2_
     feet deeper than the expected limit of erosion of the ocean floor.

     The proposed  concept'  recommended  elimination of the  "Armor Rock" covering,
     since  the  5-inch Hevicote and the  layer of  9-inch  to   12-inch  rocks would
     provide  sufficient protection and  weight.: No  change was  proposed  for the
     depth of the^outfall  below the ocean  floor. "Figure 57 'shows sketches of the
     original and  proposed  concepts.

Use Hold Down Piles  in Place of Rock Cover         •--.".-  .

     in the  original, a  layer of rock and a layer of. "Armor Rock" would cover for
     the outfall pipe.

     The proposed concept  recommended eliminating both layers  of  rock  covering
     and anchor  the outfall  to 2 pile bents  at 40 ft  intervals using pile caps
     and hold down strips.  Figure 58 shows  sketches  of the original and  proposed

Reduce Cover Over  Outfall  by 2 ft

     The  original  design   included  one foot  of 9-inch  to 12-inch rocks over  a
     36-inch diameter ocean outfall,  with an  additional 2  to 3  foot   layer  of
     12-inch "Armor Rocks."  The top of  the  "Armor Rock"  was  planned  to  be 2  ft
     below  the expected limit of erosion of the ocean floor.•

     The  proposed  concept recommended  that  the outfall be raised  two  feet,
     placing the  expected limit of erosion  at the surface of  the layer of  "Armor
     Rock."                           '.':'...      '   '.•-'.--"         /•.,-".

                                                OCEAN OUTFALL.
                                                Covering Material
                                          LIMIT OF EROSION
                                            NATIVE BACKFILL
                   ORIGINAL CONCEPT
                                         LIMIT OF EROSION
                                             NATIVE BACKFILL
                 PROPOSED CONCEPT
Figure 57.  Eliminate  "Armor Rock" covering.

                                              OCEAN OUTFALL
                                              Covering Material
                                     LIMIT OF EROSION
                ORIGINAL CONCEPT
                            OCEAN FLOOR
              PROPOSED CONCEPT
     Figure 58.   Use hold down piles.
                                            NATIVE BACKFILL

                                                           OCEAN OUTFALL
                                                           Construction Material

Change From Steel to PCCP

     The original outfall  design  used  a  steel pipe  with  epoxy  phenolic  coating on
     the interior  and coal  tar epoxy plus  two inches  of  mortar  coating on  the

     The  proposed  concept  recommended  constructing  the  pipe  of PCCP,  with j5
     1/2-lnch nonfloat concrete covering on  the outside.

Reduce Wall Thickness of Pipe

     in  the  original  design a  steel  pipe  outfall  with  a  wall  thickness  of
     5/8-inch  had   an  internal  coal  tar epoxy  coating and  a  3-inch to  5-inch
     layer of  "Hevicote" on the exterior.

     The   proposal  recommended  reducing  the  wall thickness from  5/8-inch  to
      1/2-inch.  Interior and exterior coating  on  the  outfall pipe  would  remain

 Substitute Reinforced Concrete Pipe for Final Effluent Box Conduit

      The   original   design  used  a  final  effluent conduit  box  constructed  of
      poured-in-place concrete.

      The  proposed concept recommended using precast reinforced concrete pipe.

                                                            OCEAN OUTFALL
                                                            Construction Technique

Reduce Radiographic  Inspection                      ^                  ,;

    .. The  original design  used welded  steel  pipe with  full circumference  radio-
  ,   logic  inspection  of. the  welded  joints  in  accordancewiththeAmerican
     Petroleum  Institute  (API) Specifications.                  •

     Because  the outfall  would be  operating at  low  pressure,  it was  suggested
     that  AWWA  Spec.  C200 for  pressure  testing be  used  instead of  radiologic
     testing. However, radiologic  testing was recommended on  10% of  the  joints
     fpr verification  purposes.  '.          '...-;.•-        ,   '              '

Join Pipe Above Water

     The  original design  used '16  ft  lengths  of reinforced concrete  pipe  with
     individual pipe lengths  joined beneath the water surface.
    •_            ^ : 'in •__._ i'^j^je,^ "'""„'.;„ ,.„„	 „,...* „.  .„— ,. . „„ , , ,  ,  "; ,„ „  ,"   „„    ,      •   t.     '  '.   .
     In order  to reduce  construction  and - underwater  time,  the proposed concept
     recommended  joining  two or more lengths of the  pipe prior to placement  in
     the water_for final positioning.

                                                                  OCEAN OUTFALL
                                                                  Design Concept

Eliminate Transition Structure

     At the  transition point between  the  rigid land  section  and the  semi-rigid
     ocean  section of an  outfall,  a transition  structure was  provided.  This
     structure housed  valves for  insertion of  the  cleaning pig  into the  ocean
     section of the outfall.

     It was proposed to delete the transition  structure  and replace  it with solid
     piping and a flexible  connection. The  pig insertion location  would be at the
     treatment plant  site.  This  location  would allow cleaning  of both the  land
     and ocean sections of  the outfall.

Eliminate Diffuser  .

     An outfall into a large  river had a 200 foot diffuser, for  dispersion of the
     effluent. No  regulatory agency requirement, direct  or  indirect,  was  evident
     for the diffuser.

     The proposed  concept suggested  that the diffuser be eliminated.

                                   APPENDIX  A

     The EPA's mandatory value  engineering program has been in effect since 1977,
with a voluntary program in  force  for  the  previous year (1976). Value engineering
studies completed  under  the  mandatory program, comprising  93  individual workshop
reports, were used to evaluate the  effectiveness of  the program.  The evaluation
encompasses subjective and objective conclusions  due  to the  nature  of  the data.
Subjective  evaluations  present  conclusions based on   opinions  expressed  by  the
EPA's  Regional  VE  Coordinators and discussions   with VE  consultants.  Objective
evaluations were based on  the data abstracted  from the 93 reports.

     The VE evaluation is  presented under  the  following general categories:

     •    Productivity of  VE Teams
     ซ    Potential VE Savings
     •    Acceptance  of VE Recommendations
 -.-  i .*    Identification of  High  Cost  Components         ,
     •    Composition of VE  Teams
     ซ    Costs and Level  of Effort for VE Studies
     •    Reasons  for Rejection of VE  Recommendations
     e    General  Observations

     In  addition,   a  comparison of  the  effectiveness   between  VE  teams different
from the Design firm  and VE  teams selected from  the Design firm was made, and  is
included in the following  discussions.


     One  measure   of  the VE teams'  productivity   is the average  number of ideas
evaluated  by each team member.   This  is  the only  item  for  which  data  can  be
directly abstracted from the VE reports.  The  resulting values are shown in Table
A-1.                 ...       .•''..     .      .
                    TABLE A-1.
Standard deviation

. 2.82
Ideas evaluated per team
VE firm
VE firm
      Inspection of  Table  A-1  shows  that separate  VE  firms evaluate  about  76
 percent more ideas than VE teams from the same firm as the  designer.

      The significance of this fact is clouded by many  issues  such  as:

      •    Complexity of design project
      *    Competance and experience of design firm

     •    Exposure of VE  team members to design from different firms
     •    Experience of team  members  in participating in workshops

The complexity of the design  project  influences the time required to consider and
evaluate various ideas. If  the design is complex, it takes longer to seek out and
identify the design alternatives.

     The  second issue  interrelates  with  the presentation  of the  design.  Firms
with greater experience generally think through the design thoroughly, by drawing
on past experiences, and  thereby minimize the number of alternative designs. More
experienced  firms  avoid  obvious  design  deficiencies,  which  are  frequently
introduced by less experienced firms.

     The third  issue also involves experience, but this time it relates to  the VE
team member. Team members who have had extensive exposure to designs by different
firms  can  identify  alternatives  quickly  and  competently.   Exposure could  be
obtained  through plan reviews  or by visiting  operating treatment facilities and
observing the good and  bad features at each location.

     The  final  issue  deals with  the  number of  workshops  completed by individual
team  members.  There tends to  be a  learning curve  effect  in VE workshops that
indicates  improved proficiency in identifying and  evaluating alternative ideas
with each  successive  workshop. In  other  words,  the efficiency of individual team
members increases with  the number of workshops completed.

     However, these issues are more applicable to  individual projects  and not the
whole program.  Therefore, although the  constraints presented must be  considered,
there is  a  definite trend that shows VE teams from a different firm are more pro-
ductive  than VE teams  from  the  design firm.  Many  subjective  reasons  can be
developed around this  phenomenon, such as: the VE  teams from different firms have
to  prove  their  capability; or the VE  team may  want to show  up  the   design firm
because  of past  grievances;  or  the  VE teams  from the design  firm have similar
design philosophies and therefore do not recognize potential alternative  ideas to
achieve equal functions;  or VE teams from  the  design firms do not want to  create
problems  for their firm  and  peer engineers and  therefore  are  not as  thorough in
their reviewing of the project. Any  one  or more of these opinions could  apply to
several  of the  VE  studies,  but  it  is  improbable that these  or  similar reasons
would permeate  the whole program. Therefore, it  appears that  a VE study by  a firm
different from  the  designer is more productive.


      The  potential VE savings  have been  computed as  a  percentage  of the construc-
tion  costs to eliminate the effect of project  size.  These  data were developed  for
various  points  in the  design schedule  represented by  the percent design  comple-
tion  stage.  To  identify  the  potential  savings attainable  at  various  points
through the design,  the  same  ranges  in percent of design completion  presented  in
Table A-2 were  used.  The results  are shown in  graphical  form  in Figure A-1.

     Inspection  of Figure A-1  clearly  shows  a point  of diminishing, return,  in
terms of the potential  savings,  the closer the design is to completion. The .shape
of this  curve  is  consistent  with the classic  curve published  in  texts on value
engineering which  depict a lower potential savings with time.

     The potential savings  have been subdivided  into those  developed by VE teams
from firms  other than  the Designer's firm and  those VE teams  selected from  the
design firm. The results are  shown in Figure A-2. As would be expected  from Table
5 on productivity,  the  VE teams from the Design firm identify a smaller potential
savings':than  those VE  teams  from different  firms.  Probably, many of the issues
suggested for  lower productivity of the VE team  from the design firm are  applic-
able to  this  situation also.  The most  probable  reason is that the team .members
from the Design firm are entrenched,  even subconciously, in the  standard design
methods used by'their  firm  and therefore do not see  alternatives that are.obvious
to others from outside  the  firm. They tend to be less  "creative" in terms., of  dif-
ferent design: approaches.     •       •                 '              ,--..'••   <     ..• ; ,;

     Another method of identifying  the  effectiveness of the VE teams in  develop-
ing  potential  savings  is  to  compute the savings  per team  member. For the  VE
studies  that  included  more  than one workshop,  the potential savings from each of
the  workshops  were  summed and divided  by  the  total number  of-: team .members  from
all  the workshops.  The results of  this  analysis  are shown  in  Table A-,2.  The
overall 'average potential savings  per  team member  is  $353,100. Separate. VE  team
members  have a higher  average potential savings than some VE teams.          ;  ,
Standard deviation
VE firm
"•-.'-• Same :
VE^firm , .
.'-• ; ,$238,400
, $110,800
      The potential  savings are  presented  in  terms  of  life  cycle costs,  which
 includes an  allowance  for operation  and  maintenance  (O&M)  costs.  However,  as
 described in more detail'in  a later section, very  few  of the VE  reports include
 O&M costs,  and therefore the savings presented  represent  principally initial cap-
 ital savings.  Less  than   15  percent of  the reports include  O&M  costs of  any
 magnitude.                             •                                          .

      A further analysis was  performed to  identify  the  potential  saving in  terms
 of. dollars ,($) per idea by comparing these unit values for  potential  savings, an
 indication, of the magnitude of the  individual ideas.  The  results of this analysis
 are shown in Table A-3. The  12. percent  difference in the  values between the same
 and separate VE  teams is  not considered  significant when considered  in conjunc-
 tion with the methods of  costing of the  various ideas recommendation.; The  "mix"
 of  ideasr,  that  is the, ratio of  large 'value ideas  to  small  value ideas' is  not
 known,  and therefore  further deduction cannot be made using  this data.
                                       ' A-3


g   60

UJ   40




_J   30


                          MAXIMUM SAVINGS
                                                          -^- MINIMUM SAVINGS
            20        20-40      40-60       60-80       80-100

              TIMING OF WORKSHOP  % of design comp letion

             Figure A-l.   Potential  VE  savings.




                                              Q  IN-HOUSE VE FIRM

                                              •  SEPARATE VE FIRM
          , 20        20-40      '_ 40-60"     60-80       80-100

              TIMING OF WORKSHOP. % of design completion
                   "A-'2. .-Potential VE savings.

                      TABLE A-3.   POTENTIAL SAVING PER IDEA
                                            Potential Per Idea
                                                Separate                 Same
Item    	Overall	    VE firm	VE team

1Values in Table A-2 divided by  values in Table A-1.

     To obtain yet another  perspective on the  amount of potential  savings that
could  be  anticipated,  a  dimensionless graph  showing  a trend  line  was prepared.
Using  the  historical data,  the  ratio  of  potential savings  to construction cost
was plotted  against  the  construction cost. This curve is shown in Figure A-3, and
clusters  the data points  in a more orderly  fashion.  The trend  line  was located
using  professional judgment, and can be used to judge the effectiveness of  the VE
study. VE  studies  with identified potential  savings that fall  on  the trend line
may be represented as  average, below the line is below average and above the line
above  average.

     To show the  "shotgun"  scatter  of the data points,  Figure A-4 was prepared.
This figure  plots  the  data points of potential savings against construction cost.
It is  interesting  to note the wide  range  of  potential savings in the $10 million
to $20 million construction range.  Potential savings  range from a  low close to
zero  up to  about  $4.5  million!  Possible  reasons  for  this are too  numerous to
list,  and  can  only be  deduced by  subjective  analysis. They would probably  center
around combinations  of "bad"  and  "good"  designs.  For example, the high potential
savings could  have been produced by a" "good" VE team and a  "bad" design, with the
reverse  being  the case  for the  low  potential savings  point.  "Good"  and  "bad"
could  be  represented generally by experience  for both the VE team members and the
design firm.


     The  most  important aspect of the  EPA's  VE  program and the VE studies  is the
rate  of acceptance of  the VE  ideas  or recommendations. Data were abstracted , from
the  individual workshop  reports  that  contained estimates  for both the potential
savings  and the accepted savings. These  data were converted into percentages of
their  respective  construction costs and then  arranged under the  percent of  design
completion,  as described in the  sub-section  on Potential VE Savings.  This  analy-
sis was  completed for  the dollar amounts  accepted  and the number of  ideas/  recom-
mendations accepted.  The results  are presented  graphically  in  Figure A-5. The
curves in Figure  A-5 are in general agreement by  showing a  greater  rate  of  accep-
tance  early in the design,  and then again later in the design.  The  lowest  accep-
tance rate is  found at  about the mid-point  of the  design  schedule. The  average
acceptance rate for the  dollar  values  is  about  46  percent-  while  that for the
ideas/recommendations  is about  44  percent.  The evaluation of this  category for
the  VE teams  from separate firms  and  those from  the  same firm., resulted in  an
interesting reversal as  was shown in  Table A-4. The VE  teams from  the design  firm
have  achieved a better  acceptance rate than  those  from separate firms. There are
several reasons that could  explain  this fact. These include:





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            20        20—40       40-60      60—80     80—100

                       TIMING OF WORKSHOP, % of design
       Figure A-5.   Acceptance  rate  of VE  ideas.

                                        Acceptance Rate, percent
                                                Separate                 Same
Item	Overall	VE firm	VE team
  Average                45.6                    39.2                    52.5
  Standard Deviation     25.4                    23.7                    24.8
Standard Deviation



     •    Frequently,  the VE teams  include  firm principals,  supervisors  or more
          senior  personnel  than  those  on  the  design  team,  and  therefore  the
          design engineers may  feel  pressured to accept the suggested ideas.

     •    The  ideas/recommendations  suggested  by  the VE team  probably  do  not
          include  ideas  that are totally foreign to the design firm. (They do not
          offer  a  fresh point  of  view to the  design).  In other  words,  they fit
          into the  general design  mold expoused by the design firm.

     •    Peer pressure  may  play a role in that  the  design engineers and VE team
          members  have to work together on  future projects.  Greater acceptance
          may relieve  any possible tensions.

     •    Eliminates  the "not  invented here"  syndrome,  and  therefore  the ideas
          are  more acceptable. This  would  occur  principally  in  long  standing
          firms  who have developed  standardized  methods for  designing certain
          items  and facilities.

     •    There  would  also be less skepticism about the motives of  the VE team  in
          suggesting alternative designs.

     A  second  analysis was  completed  to determine  the accepted dollar saving per
team member,  and the  results are  shown  in  Table A-5. This  table  shows a signif-
icantly higher accepted  dollar savings per team member for VE teams  from separate
firms than  for VE  teams  from the  design firm.  This statistic would tend to indi-
cate that separate VE teams  identify  more  ideas/recommendations with significant
savings,  which obviously would create  substantial design changes.  These higher
values  also  could  be  reflected  in  the  estimated operation   and maintenance
savings,  which extend over  the  life  of  the  project and are  born  entirely by the
local community.

     To deduce  the magnitude of  the  ideas  accepted,  the  ideas' accepted per team
member  were computed, and  in  conjunction  with Table A-2,  the dollars  per idea
were  obtained,  as  shown in  Table A-6.  Inspection  of this table  shows  that the
dollars per idea accepted for separate VE teams is about  111 percent  greater than
for the VE  teams from  the design firm, which is a  significant amount. It tends  to

                                    •  Acceptance per team member, $1,OOP's
                   VE firm
                                                                      VE firm
Standard deviation
Average 	 . •_•..
Standard deviation

.0.21 .'
Acceptance rate
- - * - - . . -. ' '
VE firm
. 0.42 :

VE firm
ideas  for VE  teams from the design firm than for separate VE teams. VE  teams  from
the  design  firm show a:higher •acceptance of smaller  ideas,  which together  total
to a higher value  than -for,separate teams. However, this fact  also, indicates  that
there  are fewer radical or different design.approaches, which  might be  considered
less creative or imaginative by some people.

     Finally, to test whether the  rate of acceptance  was  affected by,  the  report
presentation  and;  organization,  each  of , the workshop reports were  subjectively
rated.  The  rating was based  on the  ease with  which data  could be abstracted,
report organization,  inclusion of  unnecessary extraneous  material, conformance
with the  EPA  format, thoroughness evaluation and the  overall appearance.
Naturally considerable personal preferances are included in  the  ratirigs,  but  they
do tend to  identify trends. The ratings were divided  into three  categories: below
average,  average',  and,above average. The major determining factor was conciseness
and  clarity of the reports. The results are plotted graphically  on Figure A-6 and
show a distinct improvement in the rate of acceptance with an  improved  report.


     To obtain an indication of the-high cost components of wastewater treatment
facilities, the bid.tabulations'of-several treatment  plants  were studied, and the
costs  were  divided  into  the standard 16 division  format  recommended by  the  Con-
struction Specifications Institute  (CSI).  Using these costs,  their percentage of
the  total cost was Determined and is presented in Table A-7.

       80 _

       70 -
       60 -
       50 -


                                   REPORT RATING
Figure A-6.  Acceptance  rate based on report presentation and organization.

 • .      -  '       -                 _  ซsjฃ- '" " "• " '- ' "" "  "W.yi*:"-; "         "   '      -  -. , .
     Inspection of Table  A-7  shows the major  costs  for  a wastewater facility are
in  concrete,  equipment  and  mechanical  divisions,  each representing  about  20
percent of project  costs. The next tier  of  costs  are included  in the  site work,
metals, special construction  and electrical  divisions, representing between 5 and
11 percent  of the project cost.  The remaining nine  divisions combined make  up
only 9.6  percent  of the  total construction  costs.  However,  although  these nine
divisions  make   up  a   small   percentage   of  the   total   constructions  cost,
individually,  they could  represent a  significant savings to  the project.
CSI division
Percent of total construction costs
Division title Average
Mechanical ,
Special construction
General requirements
Wood and plastics
Thermal and moisture protection
Doors and windows
Conveying systems "
4.9 '
; 1.5
0 .3
- 21.7
- 18.0
- 7.4 :
- 4.0
- 1.6
- 2.9
- 3.8
- 1.5
- 0.9
- 1.0
- 1.7
- 1.4
     The  treatment facilities'used to  determine  the cost identification  in  Table
A-7  represents  a  ,cross-section  of  geographical  location,  type  of  facility  and
design  engineer. The  facilities vary  in size and complexity  and therefore  are
fairly  representative  of the treatment plants being constructed in the U.S.

      The data presented, in Table A-7 reflect the disciplines necessary  for  the VE
 teams.  Care should be exercised  in selecting team members  to  ensure an  adequate
 level of  experience  in  the  engineering 'disciplines necessary  for a  particular
 workshop.  The design  of  wastewater  treatment  facilities,   especially smaller
 facilities, is largely coordinated and completed by sanitary engineers.  Inspec-
 tion of Table A-7 shows that sanitary engineers have principal control  of over 70
 percent of  the  construction cost  of a project.  The  sanitary engineer  .normally
 selects and sizes all tankage and basins, specifies  the  equipment  and completes  a
 majority of  the  mechanical work.  Obviously other engineering disciplines  are  a
 part of any design team, but, with the exception of electrical engineering,  they
 only affect about 20 percent of the construction cost of  the project.

     These  facts  should be carefully considered  when  assembling a VE team. Also,
the  timing  of the  workshops  is another  important  variable  to  consider  when
establishing a VE team.  As the design nears completion, the team members selected
should have  experience  in  design aspects.

     All  VE teams should  include a  minimum of  two  sanitary engineers  in order
that  they  can inter-react  and  thereby  gain  the  most  benefit in  the  creative
phase. Early in  the  design phase, architectural, mechanical and structural engi-
neers are not really needed  as the  design  is ill-defined  in  these disciplines.
Depending on  specific  circumstances, a geotechnical  engineer  may  be  desirable.
Later in  the design, when  working drawings are  available,  the  other disciplines
should  be included  if  the  type  of  facility  warrants  it.  An  architect  may be
desirable for most VE  studies because of  their knowledge  of  building materials
which is  applicable' to  more  than  the  site buildings.  Architects  may  affect as
much  as  10 percent  of  the construction cost  by accumulating the  areas  in which
they are  directly involved.

     In summary,  the VE team composition should be assembled after  carefully  con-
sidering  the following:      '                                          '

     •     High cost  components - favor more sanitary engineers
     •     Timing  of  workshop
     •     Special construction consideration or techniques
     •     Type of facilities  to be constructed

After evaluating  these  factors, the VE team can be selected.


     The  engineering costs of the completed VE studies were analyzed and the  data
plotted in  Figure A-7.  The line of best fit,  using a  least squares analysis, was
also  computed and is indicated on the drawing.  Naturally  there  will  be  differ-
ences in  VE  costs, principally associated with expenses and the overhead rates of
the firms, but this  curve  represents historical fees for a project.

     The  level of effort  required for VE  studies  was also  evaluated  from other
data  abstracted  from the  individual workshop  reports.  The total  number of  team
members  (number  of workshops  times  number  of team members  in  each workshop) for
each VE  study was plotted  against the  estimated construction costs,  as  shown in
Figure A-8.  Superimposed on this figure is  an  envelope  of the suggested level of
effort  necessary  for conducting a  VE  study.  The upper  and   lower  limits  were
established  by considering the data, experience  in conducting VE studies and  dis-
cussions  with consultants  who perform VE studies.  The envelope  represents only  a
guideline for establishing a reasonable number  of  team members  for the study and
is based  on  a minimum of one  workshop.

     To test whether there is any correlation  between the number of team  members
and the potential savings, a  second  plot  of data points  was  completed,  as shown
in Figure A-9. Inspection  of  this  figure  shows that there  does  not appear to be
any  advantage  to have  more  than  11  team  members,   at least  for the   smaller



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1 '10 100 1,000
                           CONSTRUCTION COSTS, million dollars
                                                          SEPARATE VE FIRM
                                                          IN-HOUSE VE FIRM

                                                          VOLUNTARY VE PROGRAM
                          Figure  A-7.  VE fees.

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     In responding  to  the Preliminary VE Reports, Design engineers have developed
and used  an  enormous variety of reasons  for  rejecting ideas/recommendations sug-
gested by VE  teams. However, analysis of  the reasons used tend  to  show they are
variations of a theme,  and can  be  grouped into a relatively small number of basic
reasons.  These basic reasons are presented and discussed in this section. In many
instances, if  the VE  team  could specify  locations where  the  process, equipment
item,  type  of material,  etc. which  is  suggested  in the  idea/recommendation is
successfully used,  many of the  Designer's concerns would be alleviated.

     •    The  most  important  single  reason   that  frequently  underlies  the
          Designer's rejection of  an idea, is the  liability  issue. The Designer
          has  the responsibility,  and the liability, of  ensuring a reliable and
          fully  operational  treatment facility.  If a  Designer is  obligated to
          accept  an idea  that he does not understand, has  not  designed  into other
          projects, or does  not like,  he may  request  relief  from liability on
          that specific item.

     •    A  reason  used  frequently,  and that  is   difficult  to dispute,  is the
          probable  "delay"  that would be caused by implementing an idea. The VE
          team normally includes redesign fees and  makes allowances  for estimated
          times  based  on their  own experiences. These  may be substantially  dif-
          ferent  from the Designer's estimates, which would have to  prevail.

     •    The  most often used rejection  is basically one  of  "opinion" on a  par-
          ticular  item.  The Designer's   opinion  is  then  pitted against  the VE
          team's  opinion, and the client  is  frequently  left with making the  final
          decision. In many  cases,  it represents  an "easy out" for the  Designer
          who doesn't  believe  in  the VE  program or doesn't  want  to  be  bothered
          with changing  the way  he  has  designed  this  item on other jobs.  It
          therefore  harbors  a generally unimaginative  approach   to designing
          wastewater treatment facilities.

     •   Many Designer's  have used safety  aspects to reject  ideas. These  can
          extend to all  areas of  the design including  equipment, roads and  tank-
          age. Using safety  as  a  rejection reason  is difficult  to  counteract,  as
          any VE team that  voices  an  opposing opinion  could  be   considered  as
          being  unconcerned about  the  safety  of  plant personnel.  It  therefore
          becomes an emotional issue.

     •    Many ideas are rejected  by the  Designer  on the advice of  equipment sup-
          pliers and vendors. This  normally  occurs  with smaller, less  experienced
           firms   that tend to rely  on suppliers  for  design  help.

      •    Geotechnical information has  been used  to reject  ideas   as  well.  This
           occurs when  the  geotechnical  report  was  not  made  available to  the  VE
           team  for  whatever  reason. Typically,   these  are  valid reasons  for

      •    In some  cases, a  good idea is  rejected because it is new technology and
           the designer did not want to  take a  chance  on failure.  However,  with


          the new Innovative/Alternative  program introduced by the  EPA recently,
          these may not occur as frequently,."                                   •

     •    A rejection  that has  been used  occasionally  is  an  admission by  the
          Designer that he did not provide adequate  background material. The sug-
          gested recommendation  is good,  but because of  these other  considera-
          tions, of which  the VE team was  not  aware,  it cannot  be implemented,
          and must be  rejected.  The VE Team  Coordinator  (VETC) therefore should
          ensure that  all  available  and  pertinent  information  is  collected  for
          the workshop.  The  presence of an  Owner's representative  at the  work-
          shop is another method that can be  used successfully to stem this type
          of rejection.                                         .

     •    Another type of  "rejection" is> based  on previous  implementation of the
          idea. The Designer's  response  is typically,  "That's a  good  idea  which
          we have already  incorporated into the design.  Unfortunately, the  draw-
          ings showing this change  were  not available for the VE  workshop". This
          rejection really is an  acceptance of  the  idea> ' which is  the intent of
          the program, but a rejection of the VE7team's  recommendation.

     ฎ    One rejection used infrequently was based  on the fact that a regulatory
          agency required that the  original item be  incorporated into the design.
          In  this  case,*  the  specific  item  should  have  been listed  as a con-
          straint, and not allow the  VE  team,:to  waste valuable  time  evaluating
          alternatives for this item.          •-:

     •    On  several  occasions  an  idea 'initially  has been  accepted by  the
          Designer, only  to  be rejected  later. Later rejection is  usually based
          on  a  more  detailed re-evaluation of the  idea  and its  affect  on  other
          facilities in the plant.  Rejection  could be based on cost or other fea-
          tures such as incompatibility with  selected equipment,etc. This type of
          rejection is unavoidable,  because it is based on a more  careful evalua-
          tion by the Designer, who 'initially had liked the idea.

     •    The final rejection listed here is the idea of flexibility, which has
          already  been included- under the rejection based  on opinion.  In this
        •  case  the idea  relates  to  the "required"  amount  of  flexibility  and
          therefore infers  a predetermined  judgement.  Typically,  it  is used in
          cases such  as  "Fewer  units don't provide  the  required amount of  flexi-
          bility". The VE  team should be  provided with all documentation  relative
          to  any specific  requirements of the design.

GENERAL OBSERVATIONS               '       -     r •

     Many observations were noted  during  the  review of the 93 individual  workshop
reports, and  these are presented  here in  an effort,to improve the overall program
by identifying  pitfalls  and successes. Hopefully, if future design engineers and
VE team members review and think  about these  comments, everyone will benefit from
performing Value Ingineering  studiesi Many observations are similar to those pre-
sented  in  the EPA manual  on  Case  Studies  (EPA-43019-77-009). The  following are
the  general observations.

The VE program  has  been eminently successful when  measured in terms of
estimated life  cycle cost  savings.

For the open minded participants  in  the VE process, the VE workshop has
broadened horizons  on  alternative design techniques.  The  program actu-
ally provides a good mechanism for  the exchange of  ideas  and informa-
tion regarding  wastewater  treatment  facilities.

Participation of  an owner's representative in  VE workshops  has  proved
beneficial  to  both parties.  The VE  team gains  from the  background
information provided by the  representative while this person gains from
the frank 'discussions  about  alternative ideas,  which therefore give the
owner a better  understanding of the  ultimate facilities.

Participation in  the VE process builds  a  greater  awareness of investi-
gating  design  alternatives  and  thinking  through  the  proposed  design
more  thoroughly.  Any  designer who  knows  his  project  is  going  to  be
value engineered  will  tend to  be  more  thorough  in  the design and offi-
cially evaluate all elements of the  design before they are submitted to
the VE team.

Increased frequency of  participation  in VE workshops  sharpens  skills
of  the  team  members.   This  results  in more  efficient and  productive
workshops. Participants know what to expect and  are  use to the formal-
ities of  going  through  the  five  VE phases,  and are  able  to recognize
high  cost  areas  quickly.  New team  members tend  to   feel  insecure and
some pressure as  they  don't  know  what to expect next.

It is apparent  from reviewing  the workshop reports and participating in
value engineering studies that designers  frequently  do not  understand
the  alternative.  As a result, good ideas  are often rejected.  It  is
important to ensure that ideas are well presented and explained.  When-
ever possible,  sketches should be used for each recommendation,   along
with  clear,  concise  and  legible computations  and  notes showing all

Many preliminary  VE reports contain poor backup notes  relating  to the
specific recommendation. The Designer  therefore has  difficulty in fol-
lowing  the  recommendation through  and  rejects  the idea.  This observa-
tion follows from the  previous one.

Many recommendations presented in preliminary VE reports encompass more
than one idea.  Frequently, the whole recommendation is rejected because
of a  single  bad idea and  several  good  ideas are  lost.  VE teams should
be encouraged to  include only a  single idea in each recommendation and
avoid the  concept approach. The  latter approach  could  be incorporated
by combining several individual ideas to show an overall suggestion.

Each  recommendation page  (worksheet  10  in  the  VE workbook)  should
include a  concise description of the  "before"  and  "after" concepts of
the idea. Including these will demonstrate  to  the  Designer that the VE
team has grasped  the intent  of the original concept. Conversely, if the


 VE  team is  incorrect  in  their'  interpretation  of  the  concept,  the
 description presented will clearly1identify  the  error.  This  requirement
 will  also   improve  communication' with  third  parties  reviewing  the
/reports, such  as  regulatory agencies,  personnel not directly  involved
 in  the  process  (council  members),  and  other staff members  from  the
 Designer and VE firm's.

 The concept  of including  only a  single idea per recommendation  will
 result in many recommendations that  are mutually exclusive.  This is not
 a detraction, but rather it presents an opportunity for the  Designer to
 select  an  idea  from a  number  of  good ideas.  It  also  provides  the
 vehicle  to present  several alternative methods  of accomplishing  the
 same function.    :

 Discussions with regulatory personnel,  VE teams and designers  indicates
 there is  some distrust of  outside  firms doing the  VE.  This  is  espe-
 cially true, if the  firms  are  from the  same  geographic  area  and compete
 regularly  for  projects.  This probably  will  become less  significant as
 -time .passes, ,and  the  VE  process  is   more  understood  by  consulting

 There has  been.much criticism  of  the VE program by consultants who feel
 that  their design  capability  and integrity  are being questioned,  and
 that the program  is not  warranted. Their selection as  the Design Engi-
 neer by the  client indicates  they were  the  most qualified for the pro-
 ject. These  people fail to  realize  that VE  is  not an imposition  or  a
 slur on  their  ability,  but rather VE provides an opportunity to obtain
 differing  viewpoints from other knowledgeable engineers.  There is room
 for improvement  on any design or project and VE provides the opportun-
 ity to  tap these  ideas at  relatively little  cost.

 Most  of the  savings identified in the  VE reports  were related to  ini-
 tial  costs.  The inclusion  of  operation  and  maintenance  (O&M)  require-
 ments was  singularly poor. Even though much O&M data is already avail-
 able  in several  published and unpublished  reports, there  should be  a
 single  publication containing a comprehensive O&M cost guide on waste-
 water treatment  facilities.                   .

 Many  reports  reviewed  were inconsistent in  the  method  of  completing
 life  cycle costs (LCC's), and .some  did not  even include these  computa-
 tions.  It is  imperative  that LLC's   be  completed  as  accurately  as
 possible.   This   suggestion  also  requires   additional  cost   data   as
 : mentioned  in the previous observation.

 Many  of the reports were  very badly  organized  and contained totally
  inappropriate information. Review of  the Preliminary  VE Reports  would
 be easier and quicker if  the  general  EPA format  is  followed by the  VE
 team.  This will ensure uniformity in  report  content and elimination  of
'.• unnecessary  information.   As  shown  earlier  .in  this   chapter,  poorly
  organized .and presented  reports  result in  a  lower  acceptance  of  VE

There appears to be  a  tendency in VE teams to  strive  toward the "goal"
of identifying  savings in a ratio of 10 to  1  over the VE  fee.  Another
item is the  "bean  count"  factor which requires  that  the  VE team evalu-
ates at least 3, 4,  5,  or more ideas per team  member  to  show they have
done their work competently and thoroughly. Frequently,  these  two fac-
tors cause the  VE  team to lose sight of  the  purpose  of  the VE program
and in their zeal  to achieve their "goal"  or  "bean count" include ideas
that they would not  implement  themselves.  VE  team  members  should be
encouraged to  consider all ideas  carefully and develop the alternative
as though they  were  going to use  the idea  on  one of their own projects.
VE teams  should also be encouraged  to  identify those ideas/recommenda-
tions  that  are not  as good as the  others  or  would not  be  "pushed" by
the VE team.

The VE report  should  include  an  abbreviated description  of the project
including  background  history, and  proposed  project  elements,  design
criteria  and any special items.  This description should  not exceed two
pages, and  would provide the  reader with an  immediate overview of the

There  was very  little attention  paid  to  energy  consumption or energy
recovery  in  most of the VE  reports  reviewed.   VE  teams should be urged
to  take  account   of   energy  requirements  and  identify   comparative
requirements.  Energy  recovery systems should also be investigated  in
more detail  to determine their cost-effectiveness in offsetting energy

The Designer's responses to  the  VE  team's recommendations  tended to  be
long winded and often  circumvent the  subject. Responses should be  con-
cise  and  as short  as possible, commensurate  with  ensuring  that the
response  is understood.  If  the  idea/recommendation is accepted,  simply
write  "Accept"  for this  item.  Only  items that  are  rejected  need  an

There  has been a  wide variation  of idea  acceptance  in the VE  program.
Typically smaller,  inexperienced firms  reject  ideas on  the  basis  of
personal  preference,  less  qualified  opinions,  and  recommendations  of
others.  Larger, more  experienced firms,  tend  to  reject ideas  because
they  hold their own ability above that of•the  VE team. They also  resist
changes  to  their  standard way of design facilities.  The  VE team  must
develop clear ideas that  are well explained with examples  of  where and
how the  ideas are to  be implemented.

VE teams from the Design  firm tend  to  be less  critical  of  designs  than
VE teams from  different  firms.  There is probably a  subconscious  effort
not to make too many  changes that would  delay the  design completion.
Their idea/recommendations tend  to be minor in a  possible effort  to
 avoid major changes.

Many firms  appear to  be  completing the VE  study simply because  of the
 EPA regulations,  and  not because of the  advantages  the program.  It  is
 important for  the Designer  not to be "threatened" with  a  VE study, but


                                  •.•--    .  .  .
 rather  be  encouraged  to  utilize  the  VE  study  to  design  a  better
 project.                                 . •  •      ,

 There has been much discussion on the  amount  of  information that should
 be supplied to the VE team,  it  seems that too much  information can and
 does  stifle  the  creativity  of  the  VE,  team.   The  ideal  level  of
.information  would be  that /which  allows  the  proper  development  of
 ideas/recommendations but does not  overwhelm  the team.

 The experience of -the VE team is one of the most important features of
 a successful VE  study. Experienced participants bring  broad and diver-
 gent viewpoints  to the workshop which  results  in  an ability  to effec-
 tively identify  high cost  areas  and then cost out the  alternatives. It
 is more  important to have  experienced  engineers  on the  team  than to
 require that all  team members have attended the 40  hour  training work-
 shop. Typically,  a firm sends the younger less  experienced engineers to
 these schools, but they don't have  the necessary experience to maximize
 the benefits of  the study. The VE team coordinator  needs  the ability to
 direct __the_ team's conduct, ensure  that they keep  on  track,  and main-
 tains a positive, creative attitude at the  workshop,.

 Thrt v^;  team members should be carefully selected for each specific pro-
 ject. Workshops  ;:.).-.. lucted with relatively inexperienced people resulted
 in poor reports. The discipline  and experience of  team  members should
 be dictated by the timing of  the workshop.  Early workshops require more
 process  or  conceptual  oriented  participants  while  later  workshops
 require more design and operation  engineers.

 A  workshop tends to be. less creative when the team  includes  a large
 number  of  members  from  different  firms.;  Team  members  tend to  be
 restrained in the presence of engineers from other firms. This is prob-
 ably  due to  the  unknown  ability of other engineers  and therefore there
 is a  certain  degree  of distrust.  However,  after working  together on a
 couple  of  projects, these imaginary  barriers  are  removed and  the VE
 team  functions efficiently.

 Designers  frequently take the  ideas/recommendations personally. There
 is  a  great  deal of  "pride of authorship"  in  the  designs  and  the
 Designers  naturally  "defend" and finds  excuses  for  the manner in which
 they  designed  the  facility  or  item.  As  the  program   becomes  more
 accepted,  there  should be less  of a  defensive  attitude  and  more  of a
 cooperative attitude.

 There needs  to  be a  greater, participation  in the VE process, and espe-
 cially the workshops,  of  staffs  from regulatory agencies.  This partici-
 pation would demonstrate  a  commitment to the  VE  program and  provide
 them  with  a better understanding of  wastewater  facilities design.  This
 participation  would  increase  the regulatory agencies  effectiveness in
 reviewing  various wastewater projects.  The  agency representative pref-
 erably should  not be one  of  thetproject reviewers.

The  constraints  imposed on  a VE  team should  be  listed and  explained
prior  to  the start of  a workshop. This  will  increase the  quality and
acceptability of the  teams recommendations.

Communications between the  Designer  and the VE team are  an  important
element  in the success  of  a VE  study.   It  is  important that  the  VETC
establish  positive communication  between the  Owner,  the  Designer and
the VE teams at  the earliest possible date. The VETC should  develop a
"rapport"  with the Designer  and avoid an antagonistic approach.

                                    APPENDIX B

     During  the review  of  the 93  VE workshop  reports, many  of the  ideas pre-
sented could be called  "good  design  practice".  These  ideas  addressed items that
were  inadverently overlooked  in  the formulation  of  the  initial  design.  These
design features are applicable to  most wastewater treatment facilities.          '

     The  design of wastewater  treatment  facilities  requires  anticipating poten-
tial  problems;  having a sensitivity to  the site  in  terms  of  engineering  and
environmental issues;  recognizing and including the many  details  for cqnstruct-
ability and  operability; and coordinating all component parts in order to achieve
a  cost-effective,  easily operable  and convenient  treatment facility.  It is  the
intent of this  chapter  to  identify and briefly  describe  some of the  items that
should be  considered during the design phase and in VE workshops. These items may
seem  obvious to most  designers,  but they were  not  included  in  many of  the VE
reports reviewed  during this   study.  The  items are presented  under  the following
general categories:          s'                     -.....-•

     ป     Design Criteria
     e     Site  Work and Layout
     •     Site  Buildings
     •     Structural
     ฎ     Equipment
     ฎ     Mechanical
     ป     Electrical
     ฎ     Energy conservation
     ซ     Miscellaneous


1.   Influent Design  Data. Ensure  that the  wastewater treatment plant  has been
     designed for  the  maximum  day  influent wasteloads.

2.   Design  Criteria of Unit  Processes.  Review  the  design  criteria  for each unit
     process  to ensure that it is  sized  within acceptable limits.

3.   Hydraulic  Profile. Review the hydraulic profile to determine whether or not
     any  intermediate  pumping stations  can  be  eliminated to  save  energy.  Also,
     ensure  that sufficient head exists  across the plant to pass the peak hydrau-
     lic  flows  during  the  100  year flood condition.                     •  •     -

4.   Unit Selection. Ensure that a complete  economic analysis has been completed
     before  selecting  individual  unit  processes.  The economic  analysis should
     include both  capital  and  operation  and maintenance costs  of  the system and
     an  evaluation of the  effect  the  system  may have  on other processes.  For
     example,   the  effect  of recycle  streams  from  thermal  sludge  treatment
     processes  on the biological  treatment  process;  or  the  effect  an enclosed
     aerated grit  chamber may  have on the air handling system compared to a non-
     aerated system.                                                            •


5.   Unit Process  Selection. Consider  and evaluate  all  types of  processes  that
     perform  the  same  function,  such  as   circular vs  rectangular  vs  square
     sedimentation tanks, or  the  different types  of aeration devices.


1.   Access Roads.  Ensure that roads maintaining the same  functional  access are
     located  in a manner  that minimizes  the  length of roads  in order  to  save
     capital and maintenance  costs.

2.   Road Widths.  Road widths should be commensurate with  the  projected traffic
     volumes. Table B-1  shows recommended widths.
Notes : 1 •
Total roadway width, including shoulders (feet)
Little traffic Frequent traffic
Few trucks Many trucks Few trucks Many trucks
and buses and buses and buses and buses
18 20 22 24
20 22 24 26
20 22 24 26
22 24 24 26
Maximum pavement width is 24 feet; wider roadways include snouxaers.
"Little" or "Frequent" farm machinery traffic is at the designer's
Percentage of trucks and buses is defined by average daily traffic:
ADT up to 50 vehicles - Low percentage is less than 28%
ADT 51 to 100 vehicles - Low percentage is less than 12%
ADT 101 to 200 vehicles - Low percentage is less than 7%
ADT 201 to 400 vehicles - Use high percentage figures only
American City & County:  January 1980

3.    Road Design: Evaluate  the  climatic conditions of  the area, and ensure  that
      the road bed to  accommodates these conditions  in  combination with the  pro-
      jected traffic loads.  It is  frequently better to install a higher  cost  road
      initially to reduce future maintenance costs.

4.    Fencing. Fencing around the plant  site  should be  reviewed for quality  and
      quantity.  Areas  that  will  be  used  for  future  expansion may  not  require
      fencing. Fencing materials  should  be  consistent with area  in  which plant is
      located. Rural  sitings may  ony require wire  barriers;  whereas urban  areas
      may require high security fencing  consistent  with  local  aesthetics.

 5.    Yard Piping. The location of influent/effluent  piping,  transfer piping  and
      recycle  piping  should be  examined  in  an  effort  to  minimize  the  length
      requirements. Pipe  sizes  should have acceptable velocity  ranges to maintain

      solid  suspension.  In  confined "areas  piping  should be  sized for projected
      ultimate  flows. Wherever possible,  the Return  Activated Sludge/Was.te  Acti-
      vated  Sludge piping systems sho.uld  be  simplified with common discharge  pip-
      ing  and suction headers as  much as possible.

 6.   Landscaping.  Review landscaping plans  with  maintenance requirements in  mind
      For  example,  inclusion of sprinkler systems in  arid areas and minimize  area
      covered.  Use  ground  cover  such  as  bark, chips or  gravel as  this doesn't
      require  the attention of other plantings.  Select plantings  and grass  that
      are  suitable  for the area,  and require the  least amount of care.

 7.   Site Layout.  Locate proposed unit treatment processes  in  as compact  a  layout
      as  possible.  The  more  compact  plants   require  fewer  operator  steps  and
      shorter connecting piping.

 8.   Tunnels.  Long lengths  of underground tunnel should be  eliminated unless  they
      are  constructed  in conjunction  with  other  structures  since  above  ground
      walkways  are  often less expensive.

 9.   Handrails.  Handrailings around certain open tanks  or basins may be  replaced
      with either chain link fences or,  narrow  concrete walls at lower unit  costs.
      Tank walls  can be utilized  as  the handrail by  either  bringing the walls  up
      above  the ground surface as appropriate  (42-inches)', or importing less  fill
      for  the  site.  Either of  these  alternatives  could  be  used  to  yield  an
      aesthetically pleasing appearance, and meet present OSHA standards.      .

 10.   Site Lighting. Site lighting  needs  should  meet  functional requirements.  If
      security  and  full  coverage lighting  is  required,   consider  high efficiency
      light  fixtures.                       :

 SITE  BUILDINGS                           '  l '

 1.   Buildings.  Buildings  of  similar  environmental conditions  should be grouped
      together  to take  advantage of  common ..wall construction,  less  heating,  and
      more efficient movement and access between  the different zones.        '.••:•',-

 2.   Building  Space.  Review  space  requirements  for the  specific  plant.   After
      making allowances  for future  expansions,  any  non-functional space  may  be
      deleted.                                             ;   ,"'•••

 3. •  Building  Materials. Evaluate available building materials to  assure  that the
      buildings use the most cost effective materials.

 4.   Building  Architecture.  Architectural  finishes  and  materials  should  be
      selected  to minimize  construction and  maintenance  costs.  Construction  mate-
      rials  should be commensurate with the  specific  building's function, such  as
      administration building compared to sludge  handling building.

 5.   Buildings.  Evaluate  the potential  for  centralizing  operations  processes.
      Duplication of similar process around "the site  may be combined, such  as  one
-"•'••'•"  blower building. Assure  access for 'equipment maintenance and  removal.  The

     location and size  of doors and windows  should allow for  equipment  handling
     devices.  Assure that  adequate  aisleways  and  clearances is  provided  for
     equipment and  electrical panels. Evaluate  energy requirements  of  materials
     in the exterior walls.

 6.  Roofing. Roofing systems are the most  frequent cause of  claims  and litiga-
     tion  in  construction.  Roofing systems  should be reviewed  strictly  for per-
     formance in the geographical  area.


 1.  Forming.  Form  work  is  generally the  most  expensive part of  cast-in-place
     concrete. Complex  forming for concrete tanks,  basins or  buildings  should be
     minimized to reduce  unnecessary  construction costs.

 2.  Foundations.  Review  the  geotechnical  report  for  the  proposed  treatment
     facilites to evaluate the foundations  for required structures.

 3.  Slabs.  Review  alternative methods for designing the  thickness of basin bot-
     tom slabs. Consider  slab-on-grade with minimum load transfer capability.

 4.  Groundwater. Evaluate groundwater levels at the site of the treatment  facil-
     ities.  Review  the uplift forces associated  with structures  and basins and
     the placement  of pressure relief devices.

 5.  Walls.  Basin  and tank walls  design should minimize  concrete/steel require-
     ments.  Walls   for  water  retaining  structures  require  special  attention to
     minimum cover  over  steel  and other construction details  to  ensure a water
     ti ght s truc ture.

 6.  Materials. Evaluate  construction materials for compatibility with the  antic-
     ipated  environmental conditions. Structures over high humidity areas,  such
     as  over clarifiers  or  aeration  basins,  should be  carefully evaluated  since
     steel members  may  require exotic coatings.


  1.  Pumps.  Consider the  proposed application of  the type and size of pumps. For
     example, closed itnpellor pumps  would  not be  used  for  fluids  that  contain
     sludge  or  other solids.

  2.  Pumping Systems.  Evaluate the potential for  combinating  pumps for  optimum
     operations.  A  standby  unit  should be  included to  provide  for failure or
     maintenance.  Consider the mix of constant and variable  speed pumps  to  min-
     imize both capital and O&M costs.

  3.  Bearings.  Evaluate  the  bearing  life  for equipment  such as clarifier  mech-
     anisms, surface aerators or others, that typically are used continuously.

  4.  Gearboxes. When reduction gear  boxes are  required  for equipment  operation,
     such   as  for  surface   aerators,   evaluate  the  impact  load  capability.

     Frequently,  these systems  experience severe  shock  loads  (due  to transient
     loads)  that  are  substantially higher than the rated motor horsepower.

 5.  Standby Units.  Consider utilizing  flow  equalization  storage  in  lieu  of
     installing standby  equipment throughout the plant. This may not be practical
     for  large  treatment facilities,  but a simple economic  analysis can quickly
     demonstrate  the  feasibility.

 6.  Equipment Units. Evaluate.the potential  for optimizing  the  number and size
     of  each type  of equipment  item used  in the  treatment process.  Normally,
-••;.   fewer  items  of  equipment  will  result  in  lower  O&M  costs  without unduly
     affecting flexibility  and reliability.

MECHANICAL                     .      .'                        '

 1.  Valves.  Plug valves should  be  used  for  wastewater  and  sludge  lines.  These
     .valves  seldom   clog  and  are  self-cleaning  which- results  in  lower  O&M

 2.  Pipe Materials.  Evaluate the use and location of  the piping  pipe materials.
     Less expensive pipe often can be used where ductile iron or  steel pipe have
     been used historically.

 3.  Floor Drains.  Floor  drains   should  be installed  in all  buildings  and struc-
     tures.  Water may be  caused  by  equipment  drainage,  pipe  rupture,  washdown
     practices or spills.

 4.  Clean Outs.  All  sludge piping should have cleanouts. Consider including sim-
     ilar maintenance features on all  other  wastewater  lines.

 5.  Ventilation.  Ventilation systems  should be  capable of  removing  heat  from
     operating equipment and  providing a safe  environment for plant  personnel.

 6.  Pipe Flexibility.  Sufficient flexible  couplings  should be installed in the
     piping  system so that equipment,  pipe and valves  can be removed.

 7.  Vibration Isolators. Vibration isolation dampers  should  be included  for all
     high speed or large equipment items.

 8.  Acoustics. The estimated noise levels in  all equipment  rooms  should be eval-
     uated to determine  if sound attenuation materials  is  needed to  reduce the
     ambient noise levels.


 1.  Distribution.  Evaluate   the  distribution  voltage  around  the   treatment
     facility. Frequently 5kV or 15kV distribution values are cost-effective for
     large sites.          -                                             ,

2.  Luminaires.  Review the luminaires selected for lighting to determine  if  high
    intensity discharge (HID) or low intensity discharge  (LID) luminaires  should
    be  used for  large areas.

3.  Motor Voltage.  Examine the  voltage selected  for high  horsepower electric
    motors (200  hp and above).  Frequently,  2,300 volt or 4,000  volt motors  are
    more cost-effective  than 460  volt motors  since capital  and operation  and
    maintenance  costs tend to be lower for the higher voltage motors.

4.  Variable  Speed Drives.  Evaluate  the  necessity  of  variable  speed  drive
    installation in  the  treatment facility.  These  are  frequently installed  in
    locations that could  be served  by constant  speed  drives.  Variable  speed
    drives typically consume more  energy  although the overall energy use  at the
    facility may be less.

5.  Computer. Examine the total costs and performance reliability of  including a
    computer  in  the treatment  facility.  The analysis  should include  all  costs
    associated  with  operating and  maintaining  the  computer,   which  requires
    specialized technical  abilities.  Computer sytems are  rarely  justified  on an
    economic basis, and  are  often  installed as a result  of  technical  considera-
    tions. Computer operation  of a treatment  facility  has been  shown  to reduce
    operational labor  requirements up to 40  percent,  but maintenance  costs may
    offset this saving.   Computers have proven  to be effective  for  administra-
    tive purposes  and  for scheduling and tracking maintenance requirements. The
     size/capacity  of the  computer  is  directly related to the number of interface
    points,  which  many   times  include  points  for  analytical   data  which  are
     rarely, if ever, used.

 6.   Control.  Evaluate the process  control  system's  ability for  manual  control
     and monitoring of  the  facility since  all  systems will inevitably go down for
     one reason or  another.


 1.  Recovery  of Anaerobic Digester Gas.  Digester (sewage) gas can be used as the
     fuel  for  space heating,  digester heating, on-site generation of electricity,
     engine  driven  pumps or blowers,  or  any other in-plant purpose  requiring
     fuel. Another  alternative  for  larger facilities is to clean and sell the gas
     to  local  industry or a gas  company as  low heat fuel.

 2.  Waste  Heat  Recovery. Recoverable  waste heat is often generated by engines,
     blowers,  compressors, and furnaces or  incinerators.  Specially designed  heat
     exchangers  can be installed to use waste  heat  for  space heating, to supple-
     ment  anaerobic digester heating requirements, or other similar purposes.

 3.  Cogeneration.   Cogeneration is  the  concept  whereby electricity  generated
     on-site is supplied in parallel  with the  main  outside power  source. Any
     excess  electrical energy generated flows  back into  the power company's  dis-
     tribution grid, while electrical needs in  excess  of the amount generated  is
     supplied by the power  company.  This type of  system is generally  applicable
     to areas  having  high  electrical  costs  and  for medium to  large  capacity
     treatment plants.


     Heat Pumps.  Some of the heat  contained .in sewage effluents  can  be recovered
     through  the  use of  heat pumps. Water  to water or  water to air may  use the
     effluent  as  either  the  heat source of sink.  These systems  can be used for
     space  heating or  cooling,  of  a low temperature  water  loop or to  pre-heat
     fluids that  are  to be heated to higher temperatures.
     Active  Solar Collection: This  type of system  requires'that a
     (air, water or a water/glycol  mixture)  be continuously pumped
     collectors  to adsorb solar energy (heat) and then  to  a storage
     tank  of water,  bed of  rocks  or some  combination) to  release
     heat. These systems can be used for space heating  and cooling,
     and to  supplement  anaerobic digester "heating requirements.
working fluid
through solar
system  (large
 the absorbed
water heating
     Passive  Solar  Collection:  These differ frpm the  active  systems in that there
     are  few  moving parts  and  little equipment  is required.  They are  used  nor-
     mally  to augment space heating  requirements.  Typically, the  system consists
     of translucent panels of glass,'plastic  or fiberglass  separated  from a heat
     absorbing wall or panel by an air  gap.  Either  the  wall,  or the  air in the
     air  gap,  or  a  combination  of the two is heated 'from  the sun's energy passing
     through  the  translucent panels which in turn  augments the  space  heating.

MISCELLANEOUS                        :

 1.  Corrosion. Evaluate the corrosive  potential  of  the  soils at  the  plant  site
     and  the  suitability of the materials.

 2.  Security.  Consider the security needs of the  treatment  facility  and evaluate
     the  measures necessary to  ensure that security level.

,3.  Storage.  Evaluate  the specific  locations  of the  storage  areas  and. their
     ability  to adequately protect the stored items.

 4.  Odor Control.   Review the  odor  potential  from  all  areas  of the  treatment
     faciliites and evaluate any possible public relation problems.    "         "
                                         * U. S. GOVERNMENT PRINTING OFFICE 1980 - 677-094/1126 Reg. 8