SEPA
United States
Environmental Protection
Agency
Municipal Environmental Research EPA-600 2-79-079
Laboratory -Iy1979
Cincinnati OH 45268
Research and Development
Novel Methods and
Materials of
Construction
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution-sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service. Springfield, Virginia 22161.
-------
EPA-600/2-79-079
July 1979
NOVEL METHODS
AND
MATERIALS OF
CONSTRUCTION
by
A. F. Harber
R. C. Bain, Jr.
Brown and Caldwell, Consulting Engineers
Seattle, Washington 98119
Contract No. 68-03-2512
Project Officer
Francis Evans III
Wastewater Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
This report has been reviewed by the Municipal Environmental
Research Laboratory, 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.
11
-------
FOREWORD
The Environmental Protection Agency was created because of
increasing public and government concern about the dangers of
pollution to the health and welfare of the American people.
Noxious air, foul water, and spoiled land are tragic testimony to
the deterioration of our natural environment. The complexity of
that environment and the interplay between its components require
a concentrated and integrated attack on the problem.
Research and development is that necessary first step in
problem solution and it involves defining the problem, measuring
its impact^, and searching for solutions. The Municipal Environ-
mental Research Laboratory develops management of wastewater and
solid and hazardous waste pollutant discharges from municipal and
community sources, for the preservation and treatment of public
drinking water supplies, and to minimize the adverse economic,
social, health, and aesthetic effects of.pollution. This publi-
cation is one of the products of that research; a most vital
communications link between the researcher and the user community.
Wastewater facility construction project cost reductions of
only 1 or 2 percent could save many millions of dollars nationally
in the Construction Grants -Program of P.L. 92-500. In this study
an analysis of structural high cost centers and nonstructural
construction policies, procedures, and practices was performed.
Solutions are presented for reducing or eliminating the nonstruc-
tural factors of construction that significantly increase
construction costs. Unconventional and novel materials and
methods of construction are identified that can effect cost
savings in municipal wastewater treatment plant construction.
Francis T. Mayo, Director
Municipal Environmental Research
Laboratory
111
-------
ABSTRACT
Wastewater facility construction project cost reductions of
only 1 or 2 percent would save many millions of dollars nation-
ally in the Construction Grant Program of PL 92-500. This re-
port describes areas for effecting such cost savings. Sugges-
tions were developed from a wide-ranging search for ideas
having potential for wastewater facility cost reduction. This
work was essentially completed prior to passage of the 1977
Clean Water Act Amendments; innovative technology provisions of
these amendments should stimulate more suggestions.
Two areas for potential cost saving are investigated in
this study; non-structural and structural. Non-structural areas
cover administrative, regulatory and technical policies, proce-
dures and constraints affecting wastewater facility construc-
tion. Structural factors cover the actual construction process.
Many sources were checked for ideas; although it is recognized
such a search could be endless.
Suggested solutions for problems involving non-structural
processes were developed by considering input from people di-
rectly involved in the wastewater facility planning, design and
construction process. Solutions are posed for some of the iden-
tified problems and these are ranked in terms of their potential
for implementation and cost savings. Within the top six ranked
solutions two involved expansion of the facility planning phase,
two involved design criteria while the remaining top ranked
solutions involved fast track construction management procedures
and adoption of novel ideas.
Structural aspects are developed following an analysis of
high cost centers associated with typical collection and waste-
water treatment plant facilities. The procedure for developing
unconventional and novel ideas for methods and materials of
construction is explained and ideas developed are described.
Related research included use of computer searches and contacts
with contractors, suppliers, engineers, wastewater treatment
plant operators, industry, and various associations.
The best unconventional ideas identified were flexible (in
situ form) pipe liner which enables sewers to be relined using
existing access, plastic fluid control equipment, and several
fiberglass reinforced plastic (FRP) applications including
IV
-------
digester covers, small diameter piping, and access bridges for
walkways over clarifiers and other process units.
Novel ideas identified fall under three categories: Those
readily implemented, those requiring further development to con-
firm feasibility, and those which do not appear to be cost-
effective. The best readily implementable ideas were vertical
shaft construction methods and applications, precast concrete
tanks, and reinforced asphalt pond liners. The best ideas
identified as requiring further study are shipboard treatment
and botanical foul air treatment. Other ideas including those
considered non cost-effective are identified in an Appendix.
This report is submitted in fulfillment of Contract No.
68-03-2512 by Brown and Caldwell, Inc. under the sponsorship of
the U.S. Environmental Protection Agency. This report was es-
sentially completed during the period March 7, 1977 to
November 30, 1977; however, some additional work was conducted
during the summer of 1978 which accounts for references to the
Clean Water Act Amendments which were passed by Congress in
December 1977.
-------
CONTENTS
Disclaimer ii
Foreword iii
Abstract iv
Figures xii
Tables xiii
Acknowledgment xvi
1. Introduction 1
2. Conclusions and Recommendations 4
Non-Structural 4
Structural 7
3. Development of Non-Structural Factors Affecting
Construction Cost 10
Non-Structural Factors 10
Study Methodology 10
Non-Structural Impacts 13
Effluent Limitations 13
Pre-Grant, Post-Grant, Pre-Award Time
Delays 16
Source Control 17
Plant Location and Site Conditions . . 18
Consultant Fee Structure 19
Convention of Engineering Practice and
Procedure 19
Standard Design Requirements 20
Acceptance of New Design, Methods and
Materials 22
Design for a Maximum of Prefabrication,
Precasting, Standardization 23
Degree of "Openness" or "Tightness" of
Specifications 23
Effect of "Or Equal" Clause 24
Engineer Liability 25
Regulatory Agency Cost Reduction
Programs 25
Grant Funding Eligibility 26
Contract Programming Techniques;
Turnkey, Fast Track, Pre-Ordering ... 27
Turnkey 27
Fast Track 27
Time of Year Contract is Bid 29
Bid: Periods, Times (Other Than
Calendar), Types 30
vii
-------
Lead Times 30
Bid Type 30
Time Duration Allowed for Construction. 31
Contractor's Reaction to Inspection
Requirements and Methods 31
Prevailing Labor Rates Including
Government Requirements and Regulations 32
Magnitude and Distribution of Labor
Skills 32
Distribution of Construction Trades
Required 32
Effect of Labor Negotiations for
Rates, etc 33
Size of Project, Level of Competition . 33
Equipment Cost and Availability -
Standard Equipment 34
Equipment Purchase ... 34
Equipment Storage Prior to
Installation 34
Equipment Installation 35
Equipment Startup and Testing . . 35
Equipment Supplier Bidding Require-
ments - Subcontract and General
Contract Aspects 35
Competition in the Construction,
Equipment and Suppliers Markets .... 36
Use of CP, PERT by Owner and Contractor 36
Change Order, Construction Delays ... 36
Summary of Non-Structural Factors 37
4. Proposed Non-Structural Solutions 40
Procedural Or Other Non-Structural Aspects . 40
Recommendations 40
Expansion of the Planning Phase .... 40
Project Implementation Plan ... 41
Cost Saving Features .... 42
Summary 42
Equitable Cost Distribution ... 43
Implementation 44
Evaluate Innovative Technology in
Facility Plan 45
Summary 47
Design Parameter Development 48
Design/Construction Periods 49
Consider Fast Track Construction
Management Early in Project Development 50
Cost Reduction Recommendation . . 50
Small Projects 52
Design and Construction Workload
Leveling 52
Standard Equipment 53
Adoption of Less Conservative Design
Data 55
Vlll
-------
Novel Idea Adoption 57
Discouragement of Novel Ideas . . 58
Mechanical Pre-Bid Requirements .... 59
Design/Construction Periods 61
Recommendation 62
Interchangeability Provision 62
Bid Listing Requirements 63
Objections 63
Inspector Certification 64
Suggested Form 64
Working Days 66
Change Order Evaluation 66
Conclusions 67
5. Cost Centers 70
Methodology 70
Collection Systems 70
Cost Research 71
Cost Development 72
Excavation 72
Trench Support 72
Dewatering 72
Pipe and Appurtenances 72
Bedding and Backfill 73
Restoration and Disruption .... 73
Cost Tables 73
Pipeline Cost Centers 77
Wastewater Treatment Plants 78
Data Sources 78
Selection of Typical Plants 79
Unit Sizing for Typical Plants .... 82
Overall Cost of Typical Plants .... 87
Cost Center Development 88
Unit Process Cost Breakdowns 88
Cost Centers 96
6. Unconventional Methods and Materials of
Construction 99
Unconventional Methods and Materials .... 99
Research 99
Computer Searches 99
Contractor Contacts 100
Other Contacts 100
Results 100
Potentially Cost-Effective Unconventional
Methods 101
Insituform Pipe Liners 101
Applications 101
Description 101
Advantages 102
Disadvantages 103
Cost Data 103
Trenchless Sewer Pipe Installation . . 103
Applications 103
ix
-------
Description 104
Advantages 104
Disadvantages 104
Cost Data 104
Sewer-Within-Sewer 105
Applications 105
Description 105
Advantages 106
Disadvantages 106
Fiberglass Reinforced Polyester
Applications 107
Applications 107
Description 107
Advantages 108
Disadvantages 108
Cost Data 109
Fiberglass Reinforced Polyester
Bridges 109
Applications 109
Description 109
Advantages 109
Disadvantages 110
Cost Data 110
Plastic Fluid Control Equipment .... 110
Applications 110
Description Ill
Advantages Ill
Disadvantages 112
Cost Data 112
Miscellaneous FRP Uses for Wastewater
Treatment Plants ..... 112
Applications 112
Description 112
Advantages 114
Disadvantages 114
Cost Data 114
Fiberglass Reinforced Polyester
Digester Covers 114
Applications 114
Advantages 115
Disadvantages 115
Cost Data 117
Unconventional Covers and Enclosures . 117
Applications 117
Description 117
Advantages . . 120
Disadvantages 121
Cost Data 121
7. Novel Methods and Materials of Construction . . . 123
Novel Methods and Materials 123
Idea Generation 123
External Idea Development 123
-------
Industry 124
Mechanical Equipment Suppliers . . 124
Patent Information 124
Foreign Research Associations . . 125
Wastewater Treatment Plant
Personnel 125
Computer Literature Searches ... 125
Internal Idea Development 125
Idea Treatment 126
Novel Ideas 127
Drilled Vertical Shafts 127
Implementation 127
Cost Considerations 128
Reinforced Earth Tanks 130
Implementation 130
Cost Considerations 132
Advantages 132
Disadvantages 132
Precast Concrete Tanks 132
Implementation 133
Reinforced Asphalt Pond Liner 133
Implementation 134
Cost Considerations 134
Advantages 134
Disadvantages 134
Recommendations 135
Other Novel Ideas For Further Study .... 135
Shipboard Treatment 135
Implementation 136
Cost Considerations 137
Advantages 137
Disadvantages 137
Deodorizing Foul Air with Botanical
Systems 138
Implementation 138
Cost Considerations 139
Advantages 139
Disadvantages 139
Appendices
A. Construction Cost Summaries 140
B. Other Ideas Considered in This Study 157
C. Computer Searches 172
XI
-------
FIGURES
Number Page
1 Schematic flow diagram construction grants program 11
2 Wastewater treatment plant construction cost and
effluent quality 15
3 Construction management alternatives 28
4 Treatment plant size distribution 80
5 Process schematic and design assumptions,
44 1/s (1 mgd) wastewater treatment plant ... 83
6 Process schematic and design assumptions,
440 1/s (10 mgd) wastewater treatment plant . . 84
7 Constant pressure digester cover . 116
8 FRP cover for rectangular openings 119
9 Reinforced earth tank details 131
B-l ICI deep shaft unit 165
B-2 Microflotation process 168
Xll
-------
TABLES
Number Page
1 Construction Grant Process—Participants 12
2 EPA Construction Grant Program Non-Structural
Influences 14
3 Site Location—Construction Cost Impacts 18
4 Comparative Costs of Sedimentation Tanks 21
5 Cost Apportionment 22
6 Impact of Time of Year of Bid 29
7 Impact of Non-Structural Factors 38
8 Ranking of Proposed Non-Structural Solutions ... 68
9-A In Place Cost for Sewers in Varying Ground
Conditions (1976 dollars per meter) 74
9-B In Place Costs for Sewers in Varying Ground
Conditions (1976 dollars per foot) 75
10 Cost Distribution Sewers in Varying Ground
Conditions 76
11 Cost Center Distribution 78
12 Wastewater Treatment, Plants Over 888 1/s (20 mgd). 81
13 Typical Unit Processes Wastewater Treatment Plants. 82
14 Design Details and Data, 44 1/s (1 mgd) Plant ... 85
15 Design Details and Data, 440 1/s (10 mgd) Plants . 86
16 Estimated Construction Costs 87
17 Construction & Equipment Installation Cost Summary
440 1/s (10 mgd) Influent Pump Station Typical
of Deep Structures 90
xiii
-------
18 Construction & Equipment Installation Cost Summary
440 1/s (10 mgd) Rectangular Primary Sedimanta-
tion Tanks Typical of Buried Rectangular Tankage. 91
19 Construction & Equipment Installation Cost Summary
440 1/s (10 mgd) Circular Secondary Clarifiers
Typical of Buried Circular Tankage 92
20 Construction & Equipment Installation Cost Summary
440 1/s (10 mgd) Twin Primary Digesters and
Sludge Control Building Typical of Aboveground
Circular Tankage 93
21 Construction & Equipment Installation Cost Summary
440 1/s (10 mgd) Vacuum Filtration Facility
Typical of Aboveground Precast Structures .... 94
22 Summary of 440 1/s (10 mgd) Typical Plant Costs,
(thousand dollars) 95
23 Condensed Summary, Typical Plant Structural Costs
as a Percent of Total Plant Structural Cost,
440 1/s (10 mgd) 96
24 Comparisons of Digester Cover Costs and Usable
Gas Volumes 115
25 Unit Costs for Unconventional Cover Materials . . . 121
26 General Cost Ranges for Deep Shafts 129
A-l Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Influent Pump Station 141
A-2 Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Preliminary Treatment 142
A-3 Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Rectangular Primary
Sedimentation Tanks 143
A-4 Construction & Equipment Installation Cost Summary,
440 1/2 (10 mgd) Activated Sludge with
Blower Building 145
A-5 Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Circular Secondary Clarifiers . 147
A-6 Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Chlorine Disinfection
Including Chlorination Building 148
xiv
-------
A-7 Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Gravity Thickener 149
A-8 Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Sludge Pumping Equipment .... 150
A-9 Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Twin Primary Digesters
and Sludge Control Building 151
A-10 Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Vacuum Filtration Facility . . . 153
A-ll Construction & Equipment Installation Cost Summary,
440 1/s (10 mgd) Miscellaneous Structures
Consisting of Internal Maintenance, Laboratory
and Garage Facilities 154
A-12 Construction & Equipment Installation Cost Summary,
44 1/s (1 mgd) Trickling Filter 155
A-13 Construction & Equipment Installation Cost Summary,
44 1/s (1 mgd) Aerobic Digester 156
B-l Shafts for Chlorine Contact 169
xv
-------
ACKNOWLEDGMENTS
We wish to acknowldege the advice and patience of EPA pro-
ject coordinators Mr. Francis Evans and Mr. John Smith in this
search for novel methods and materials of construction. Many
groups were contacted for information; helpful suggestions have
come from all over the world. The authors are grateful to those
who took time to respond. Particularly helpful suggestions came
from our meetings with contractors in Seattle and in Southern
California; we gratefully acknowledge Venture Contractors-
Engineers of Auburn, Washington and University Mechanical
Engineers-Contractors of Tucson, Arizona as particularly active
contributors. The Asphalt Institute provided useful information
on one of the more novel ideas and Owens-Corning Fiberglas
Corporation was very helpful in providing information on rein-
forced fiberglass polyester (FRP) applications. Many Brown and
Caldwell staff engineers participated in this work; major con-
tributors included Anthony Harber, Richard Bain, Russell Freeman,
Jack Warburton, Garr Jones, Richard Stone, Roger Wilcox, Guy
Anderson and Douglas Schneider. Special recognition is also
given to John Dally for his editing efforts.
xvi
-------
SECTION 1
INTRODUCTION
Many billions of federal dollars have been awarded to as-
sist in the construction of wastewater collection and treatment
facilities. Congress authorized 42.5 billion dollars for the
Construction Grant Program for the period 1972-1982. Most of
the 18 billion dollars originally authorized in 1972 with the
passage of PL 92-500 has been obligated; however, an additional
24.5 billion dollars was authorized with the 1977 Clean Water
Act Amendments. If cost savings involving construction cost re-
ductions of only 1 or 2 percent could be accomplished, the po-
tential return in dollars saved would be substantial. Recogniz-
ing this, the U.S. Environmental Protection Agency (EPA) and the
Municipal Environmental Research Laboratory (MERL) authorized
this study to identify areas having potential for minimizing
costs for wastewater collection and treatment facilities.
General objectives of this study as defined by MERL are as
follows:
"The general objectives are to review conventional design
practices, the design/bid/contract-award sequence, and
conventional construction procedures used in the con-
struction of sewer systems and wastewater treatment fa-
cilities; to identify the administrative, regulatory,
and technical policies, procedures, and constraints
which impact the cost of construction projects; and
to develop a universe of novel construction methods
and new materials of construction, evaluating their
applicability for use in sewerage facilities construc-
tion if unconstrained by existing criteria, standards,
and policy, in order to minimize the cost of collection
and treatment facilities."
Thus the study involves procedural and other administrative
matters as well as design and construction considerations. The
terms "non-structural" and "structural" are used throughout this
report to separate administrative procedures from construction.
Accordingly, the term "non-structural" is defined to include
all aspects which affect construction cost, but are not directly
associated with construction. Included are the administrative,
regulatory and technical policies and constraints referenced
-------
above. The term "structural" includes all aspects of construc-
tion practices and costs of construction.
Non-structural aspects of the study are approached in two
phases. Initially, various agencies and individuals were con-
tacted for their opinions; personal concerns regarding the
Grant Program were also solicited. 'Secondly, these inputs were
used as a base for the development of potential solutions to
identified problems.
The structural side of the study involved a more intensive
effort (the study effort involved time apportionment of approxi-
mately 20 percent non-structural and 80 percent on structural
topics). The first phase of the structural work involved a
state-of-the-art review of current conventional methods and
materials of construction of facilities in the construction
field. This review served as background for a cost center anal-
ysis of collection and treatment systems. The cost center work
was useful in identifying items having potential for cost sav-
ings where use of novel and unconventional methods and materials
might prove feasible.
The concluding sections of this study present unconvention-
al and novel ideas for methods and materials of construction
which were identified. Emphasis is placed on those which are
apparently cost-effective. Section 6 describes the "unconven-
tional" ideas which, for purposes of this study, are defined as
relatively new construction methods or materials used infre-
quently in the wastewater field to date. Section 7 covers the
"novel ideas" which cover ideas ranging from those used else-
where in the construction industry (but not in the wastewater
field) to so called "blue sky" ideas developed by brainstorming
techniques.
The novel and unconventional ideas were developed by
several methods; each of the two sections relating to new ideas
begins with an introductory text describing development meth-
odology and problems encountered. Other ideas considered but
which are not necessarily cost-effective or are beyond the de-
fined scope are included in an Appendix. Recommendations for
both non-structural solutions and construction ideas are out-
lined in an abbreviated form in Section 2.
It should be stressed that the scope of this study was
very broad, and in consequence the amount of time which could
be expended on each idea was limited. The cost-effectiveness
and/or practicality of the unconventional methods is proven by
actual use elsewhere. For novel methods and for the non-
structural concepts, only superficial tests of economy and
practicality could be applied. Other good ideas will undoubt-
edly emerge as others focus on this subject. This particular
search was initiated before the 1977 Clean Water Act Amendments
-------
were passed; the emphasis placed on novel methods by this new
Federal Law should stimulate a wider search. It is hoped that
this initial investigative effort will provide further stimulus
and that the methods used and ideas developed here can be ap-
plied to accomplish real cost savings in future wastewater fa-
cility construction.
-------
SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
This study evolved from the realization that small percent-
age cost reductions in individual wastewater facility projects
would represent major savings in the national water pollution
control effort. Such savings would then affect the federal
municipal wastewater facility construction grant program allow-
ing more projects to be built for a given allotment of funds.
With this premise in mind the conclusions and recommendations
from this study of novel procedural and structural methods and
materials of construction are offered.
The study identifies many different ways to effect waste-
water facility construction cost reductions. Ways to accomplish
this goal are grouped depending whether the change considered
is non-structural (e.g., administrative or procedural in nature)
or structural (e.g., actual change in construction materials or
technique). The relative importance of non-structural or struc-
tural changes can best be assessed on an individual project.
Both groups are important. Conclusions and recommendations are
offered for each group.
NON-STRUCTURAL
Many diverse non-structural topic areas were identified as
having potential for effecting cost reduction. A review of 29
areas covering all phases of the Federal Construction Grant
Program revealed a pre-grant topic, effluent limitations, as
having the greatest potential for cost savings. It was observed
that overly strict effluent standards can force design of over-
sized units or even advanced treatment where more conventional
treatment is adequate; this problem is particularly evident
where design is governed by wet weather conditions. The efflu-
ent limitations topic has the potential to change construction
costs by over 20 percent.
Other important non-structural topics include time delays
caused by agency review procedures, source control (including
infiltration-inflow), conservative engineering design practices,
standard design requirements, delays related to grant eligibili-
ty determinations and construction delays associated with change
-------
orders. These other items were all rated as having potential
to reduce construction costs by 5 percent or more; most of these
items were associated with cost reductions in the 5 to 10 per-
cent range.
Proposed solutions to procedural or other non-structural
aspects are offered; 16 proposed solutions are described in
Section 4. Six of this group were rated high in terms of their
overall potential for implementation and cost savings. These
six are summarized below with their recommendations:
1. Expansion of the Planning Phase. A two-part recom-
mendation is offered for this item as follows:
First, a project implementation plan should be
developed as soon as possible after a decision
is made to prioritize a project for funding. This
plan should include a clear description of each
federal, state and local requirement which affect
facility planning, design, construction or opera-
tion and how compliance with each requirement will
be achieved. Incorporation of compatible multi-
purpose projects in the plan is encouraged. This
leads to the second part of this recommendation
which is that equitable cost distributions between
federal, state and local interests should be de-
veloped considering multi-purpose project require-
ments and goals. Basic water pollution control
functions would be defined and costs and benefits
for achieving water pollution control requirements
would be compared with plans to meet other federal
requirements as well as state or local multi-purpose
alternatives. In this way all applicable federal
requirements are defined as a first step toward
implementation; costs for compliance with non-water
quality mandates would be recorded and more flexi-
bility in planning for local needs would be attained.
2. Evaluate Innovative Technology in Facility Plan.
To assure benefits of innovative and alternative
technology are considered thoroughly, it is recom-
mended that an evaluation should be made to deter-
mine the appropriateness of including innovative
technology in the project. This process should
begin as soon as possible once grant funding de-
cisisons are made. Where innovative technology
would appear to warrant further consideration a
detailed action plan should be developed for in-
clusion in the facility plan. As a minimum, the
innovative technology plan should:
• identify innovative technology appropriate for
the project;
-------
• include an economic evaluation of the potential
impact of the proposed innovative technology on
the project;
• include a general evaluation of the impact of
such an innovation on the national wastewater
program;
• include an assessment of the risk of failure of
the innovative technology;
• describe actions to be taken in the event of
failure of the innovation; and
• describe criteria and procedures to be used to
evaluate performance of the innovative technology.
3. Design Parameter Development. In order to determine
optimum design parameters it is recommended that EPA
sponsor performance evaluations at treatment plants ap-
proaching design capacity for one or two years prior
to commencement of facility planning. The recommended
evaluations would be facilitated by making several
related procedural changes as follows:
• EPA should provide funding for construction of
minor modifications to existing facilities so
that full-scale multi-stream process evaluations
can be undertaken.
• Both EPA and state agencies should permit waiver
or reduction of routine sampling requirements
during evaluation periods to free existing labora-
tory facilities and staff to monitor experimental
work.
• Occasional violations of NPDES permit limitations
will occur and these should be accepted by regu-
latory agencies.
• Funding for additional analysis and development
of design criteria should be allowed as part of
the Step 1 grant.
4. Consider Fast Track Construction Management Early
In Project Development. To reduce cost through
minimization of time taken in the conventional pro-
ject design and construction sequence it is recom-
mended that an evaluation should be made to deter-
mine the appropriateness of utilizing fast track
design-construction techniques. This evaluation
-------
should begin as soon as possible after the decision
is made to consider grant funding for a proposed
wastewater treatment project. Where a design-
construction approach would appear to be appropri-
ate, a detailed fast track action plan should be
developed for inclusion in the facility plan.
5. Adoption of Less Conservative Design Data. Engineers
should be encouraged to adopt less conservative
design data. Currently, the trend is to use in-
creasingly conservative design data. It is recom-
mended that EPA regulations be modified to include
provision for further funding for design and con-
struction beyond Step 3 subject to certain conditions.
These conditions would be drawn up around require-
ments that the engineer and municipality show their
intent to use less conservative data during Step 2.
6. Novel Idea Adoption. To provide conditions in which
novel cost reducing ideas can be tried and tested to
determine their suitability and cost-effectiveness,
it is recommended that EPA issue regulations en-
couraging engineers to adopt novel methods and ma-
terials, and indemnify those who do so. Further,
that a group be established to record and publish
the successes and failures of adopted novel ideas.
STRUCTURAL
Cost centers were identified for typical wastewater collec-
tion systems and waste treatment facilities; this process helped
to focus attention on high cost centers where employment of un-
conventional or novel materials or methods of construction may
prove feasible.
Evaluation of pipeline cost centers revealed that pipe and
appurtenances represent the major cost of construction under
normal and minimum cost 'conditions whereas sheeting becomes the
most costly item under maximum cost conditions. Excavation
averages about 17 percent of total costs as a fairly constant
percentage. Dewatering was not a particularly high cost center
although this cost center did represent 15 percent of the total
cost under maximum cost conditions.
Evaluation of costs for representative waste treatment fa-
cilities indicated structural elements account for slightly
more than 50 percent of total plant costs. Vertical wall con-
struction for buried rectangular/circular structures alone ac-
counted for almost 20 percent of total plant costs. Various
slabs accounted for 20 percent of total'cost, with buried rec-
tangular/circular types again representing nearly half. Digester
-------
covers represented 9.0 percent of total costs. Excavation and
earthwork costs for buried rectangular/circular structures re-
presented 8.5 percent of total costs. A lower relative cost of
formwork to concrete for below ground versus above ground struc-
tures was apparent. This represents the difference between the
more massive underground structure where finish is relatively
unimportant and the thin walled abovegrade structures where
finish for visual appearance is of prime concern.
The relative costs of mechanical equipment to total plant
costs is significant. Thirty-two percent of total costs relates
to major mechanical equipment, 14.5 percent relates to other
items of mechanical equipment. The total cost of these two
items approaches 50 percent of total plant cost. Assuming po-
tential cost savings are proportional to present cost, it is
apparent that mechanical equipment offers a promising area for
potential cost savings.
The cost center analysis proved useful in identifying
areas having potential for cost savings using unconventional or
novel methods or materials of construction; the analysis pointed
to some non-structural elements as well, particularly as related
to procedures used in specifying mechanical equipment.
Unconventional and novel ideas were identified utilizing
data from computer searches, contractor contacts and various
contacts with engineers, research groups, equipment suppliers,
associations and others. Brainstorming sessions were also con-
ducted and were an important part of the search.
Unconventional methods and materials of construction in-
clude those which, though not routinely employed, have been
proven or at least demonstrated in actual installation. Nine
potentially cost-effective unconventional methods or materials
of construction are described in the report; others are identi-
fied in the appendices. These nine unconventional items are:
* Insituform pipe liners
• Trenchless sewer pipe installation
• Sewer-within-sewer
• Fiberglass reinforced polyester (FRP) piping
• Fiberglass reinforced polyester (FRP) bridges
• Plastic fluid control equipment
• Miscellaneous fiberglass reinforced polyester (FRP)
items
-------
• Fiberglass reinforced polyester (FRP) digester covers
• Unconventional covers and enclosures.
The best unconventional ideas identified were flexible (in
situ form) pipe liner which enables sewers to be relined using
existing access, plastic fluid control equipment, and several
fiberglass reinforced plastic (FRP) applications including di-
gester covers, small diameter piping, and access bridges for
walkways over clarifiers and other process units.
In contrast, novel methods and materials of construction
are those representing promising new approaches to reducing the
cost of wastewater conveyance and treatment facility construc-
tion. Novel ideas which were found suitable for inclusion in-
clude four which appear to be cost-effective and two which ap-
pear to warrant further study. Other novel ideas are identified
in the appendices. The four apparently cost-effective ideas
are:
• Drilled vertical shaft construction
* Reinforced earth tank
• Precast concrete tanks
• Reinforced asphalt pond liner.
Other novel ideas which were not tested from a cost stand-
point but which may be worth further study include:
• Shipboard treatment
• Deodorizing foul air with botanical systems.
The best readily implementable novel ideas were vertical
shaft construction methods and applications, precast concrete
tanks, and reinforced asphalt pond liners.
-------
SECTION 3
DEVELOPMENT OF NON-STRUCTURAL FACTORS
AFFECTING CONSTRUCTION COST
NON-STRUCTURAL FACTORS
Construction of a water pollution control facility is the
most costly step in the implementation of the federal wastewater
facility grant program. The construction cost of these facili-
ties reflects decisions made through numerous steps from the
point of determining facility needs through to operational
startup. Thus the construction cost reflects, in addition to
the structure to be built, a myriad of non-structural factors
that in specific instances have a significant effect on final
costs.
Evolution of a project from initial identification of need
through plant start-up is a multi-step linear process as illus-
trated in Figure 1. In addition to those participants identi-
fied in Figure l,a large array of agencies, organizations and
individuals affect the form and cost of the final product.
Potential participants and their role as related to costs of
implementation of a specific wastewater program are identified
in Table 1.
STUDY METHODOLOGY
In the previous paragraph (Table 1) agencies, organizations
and individual groups that have an impact on pollution control
projects were identified. Their impacts were broken down into
passive and active roles. By virtue of differing roles and re-
sponsibilities, and to obtain a balanced viewpoint, it was nec-
essary to interview all parties involved. Emphasis was placed
on parties that had active participation in the program. Con-
sideration of the passive group was limited to areas where their
prior actions appeared to preclude implementation of active
group recommendations.
In the initial information search maximum use was made of
existing contacts, in-house experience, regulatory agency per-
sonnel, past and present clients, equipment suppliers and con-
tractors. To obtain a national perspective the scope of infor-
10
-------
FIGURE i. schematic flow diagram
construction grants process
legend;
CD
O
state /epa applicant decision clearinghouse
-------
TABLE 1. CONSTRUCTION GRANT PROCESS—PARTICIPANTS
Participants
Owner
Federal
EPA
Other
State
Water quality
agency
Other
City/County/District
(if not owner)
Universities
Consulting Engineers
Contractors
Equipment Manufacturers
Environmental Groups
Labor Unions
Pre-
Step 1
•
e
•
•
»
0
•
P.L. 92-500 Grant Program
Step 1
•
•
•
0
0
•
t
Step 2
•
0
0
e
o
o
•
•
Step 3
•
0
O
o
0
0
•
•
•
•
Key
• Active
ft Some Active Involvement
O Passive
12
-------
mation gathering was extended to include literature searches,
and contacts with a representative number of professional organ-
izations; including the Associated General Contractors of America,
the Wastewater Equipment Manufacturers Association, the
Association of Metropolitan Sewerage Agencies, the American
Consulting Engineers Council, and the Water Pollution Control
Federation. Contact was made initially by telephone, followed
by a letter describing the study objectives, and then further
telephone and personal contacts as appropriate. Information
response was either in the form of written comments or tran-
scripts of the various telephone and personal interviews.
At the start of this study, EPA staff identified specific
non-structural factors that had a potential for affecting facil-
ity construction costs. These items, together with additional
factors developed during the study, were categorized into sub-
ject groups representing progressive stages in the wastewater
management program. Specific points developed within the sub-
ject categories are summarized in the following section. The
subject categories and their relationship to the EPA three-step
funding program are identified in Table 2.
NON-STRUCTURAL IMPACTS
The input by identified "non-structural" elements is sum-
marized below., The order of the writeup is as indicated in
Table 2.
Effluent Limitations
The selection of a required effluent quality to be met by
a specific wastewater facility dictates the extent of treatment
facilities required and thus cost. As of this time PL 92-500
requires that all municipally owned treatment works shall
achieve a secondary standard of effluent quality.1 This pro-
vides the baseline for all discharge requirements with stricter
standards being imposed on a case-by-case basis. As indicated
in Figure 2, the higher the required effluent quality is, the
higher the cost of construction will be.
For surface water discharges, receiving waters are cate-
gorized as either effluent limited or water quality limited.
By definition, discharge to water quality limited segments re-
quire effluent qualities better than secondary. Selection of
water quality limited segments is often based on limited data,
which has resulted in large sums spent on plants without any
measurable benefit.2
Well operated biological secondary treatment facilities
can consistently meet year-round effluent BOD and SS concentra-
tions of 20 mg/1. Furthermore, under optimum conditions (warm
13
-------
TABLE 2. EPA CONSTRUCTION GRANT PROGRAM
NON-STRUCTURAL INFLUENCES
Item
no.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Non- structural factors
Effluent limitations
Pre-grant, post-grant time delays
Source control
Plant location
Consultant fee structures
Conventions of engineering practice
Standard design requirements
Acceptance of new design ideas
Design for prefabrication/
standardization
Specifications strictness/ looseness
Effect of "or equal" clause
Engineer's liability
Regulatory agency cost reduction
program
Grant funding eligibility
Construction management alternatives
Time of year contract is bid
Bid - period, times and type
Time, duration allowed for construction
Contractor perception of inspection
requirements
Prevailing labor rates
Magnitude and distribution of labor
skills
Distribution of construction trades
Effect of labor negotiations
Size of project
Equipment cost
Equipment supplier bidding restrictions
Competition in construction and
equipment field
Use of CP, PERT scheduling tools
Change orders, contract delays
EPA Construction
Grant Program
Pre-
Step 1
•
Step 1
•
•
•
•
Step 2
•
•
•
•
•
•
•
•
•
•
•
Step 3
•
•
•
•
•
•
•
•
•
.
•
,
•
•
•
,
'
•
•
•
14
-------
Raw
sewage
Effluent
quality
200
400
200
20
BOO.
mg/l
% removal
COD:
mg/l
% removal
Suspended solids:
mg/l
% removal
Nitrogen:
mg/l
% removal
20
90
80
80
20
90
18
10
5
975
40
90
5
97.5
18
10
2
99
35
91
0
100
18
10
2
99
35
91
0
100
2
90
1
99.S
10
97.5
0
100
1.5
92.5
Phosphorus:
mg/l
9
10
0.1
99
0.1
99
SECONDARY + PHOSPHORUS REMOVAL + FILTRATION * NITROGEN REMOVAL + CARBON ADSORPTION
ENVIRONMENTAL POLLUTION CONTROL ALTERNATIVES:
MUNICIPAL WASTEWATER EPA-625/5-76-012
FIGURE 2 WASTEWATER TREATMENT PLANT CONSTRUCTION
COST AND EFFLUENT QUALITY
15
-------
temperatures, low hydraulic loadings) characterized by summer
wastewater flows, secondary effluent BOD and SS concentrations
of 10 mg/1 are attainable. Discharge standards requiring ef-
fluent levels of 10 mg/1 BOD and SS on a continuous basis
achieve an improvement in water quality which is, in many in-
stances, barely quantifiable. Yet such standards dictate that
a tertiary stage is required.
Standards based on strict interpretations of statistical
discharge requirements often result in oversizing of units to
meet periodic high flow conditions. An example of this is the
rigid application of the 85 percent removal criterion to all
flows. For a sewage diluted with storm flows, influent
strengths as low as 70 to 80 mg/1 BOD and SS are not unknown.
A discharge level of 10 mg/1 BOD and SS is therefore required.
This requirement involves construction of tertiary treatment to
protect the receiving waters when they may least need protec-
tion, under heavy storm stream flow conditions. Little improve-
ment in water quality may be realized at the cost of significant
dollar and resource expenditure.
Pre-Grant, Post-Grant, Pre-Award Time Delays
Consistent with all previous federal/state funded programs,
detailed procedures, rules and regulations have been promulgated
by the grantors for the disbursement of P.L. 92-500 grant funds
and where applicable local state matching funds.
Grantees, their consultants, contractors and, in many
cases, funding agency personnel, have been critical of the
management of the grant program. Particular concerns arise
over delays due to agency reviews. Implementation of a waste-
water project is a three-step process with reviews, approvals
and authorizations required at each step. These review proce-
dures plus delays in allocation of fiscal year funds have re-
sulted in some delay for many projects.
These delays do result in increased costs, due to inflation
and more recently by compressing design and construction times
to compensate for time lost during the review phase. Review of
contracts implemented prior to 1972, the first year of P.L.
92-500 grants, with current contracts indicates a contract im-
plementation time increase of from 20 percent to 50 percent for
comparable projects.
With the exception of short delays within a construction
season, all delays will result in increased costs. Currently
construction costs are inflating at over 8 percent annually.
A less obvious effect of granting agency delays on costs
is compression of design periods. When insufficient time is
available, potential new design ideas are not pursued and design
16
-------
decisions tend to default in favor of previous design. Inade-
quate time to check contract documents results in mistakes and
inconsistencies moving forward to the construction period. The
cost of a site change order exceeds the cost of changes or cor-
rections made at the design stage. The implication of com-
pressed construction periods is identified under "Time Duration
Allowed for Construction."
Source Control
The total waste volume impacts construction cost directly.
Hydraulic elements such as pumps and sedimentation tanks are
sized on the basis of average and peak flows. Reduction of
waste volume at source will tend toward a reduction of average
flows. Reduction of infiltration/inflow will act to reduce both
average and peak flows. Thus, either greater source control or
reduction of infiltration/inflow will reduce costs, since either
peak or average flows are reduced. The exception;is where one
parameter is limiting: For example, at a plant designed to
handle storm peaks of six times average, no capital cost savings
would result from a source control measure acting to reduce
average flows.
Waste discharged to a sewage collection system reflects the
use characteristics of the discharger. Sewer ordinances, EPA
pretreatment requirements, water supply characteristics, and
water use rates affect both the waste volume and pollutant con-
tent discharged in wastewater. After discharge into the sewer,
the waste may be diluted by extraneous water in the form of in-
filtration and inflow. The total pollutant load and the makeup
of the pollutants relate directly to the size and type of units.
In general, only the biological and sludge stages are influ-
enced. In extreme cases hydraulic units may also be directly
affected: For example, several wastewater plants in central
California taking high volumes of fruit and tomato wastes use
dissolved air flotation for primary solids removal rather than
sedimentation during periods of peak cannery loads.
Industrial pretreatment requirements have lessened the im-
pact of industrial wastes in municipal treatment plant perform-
ance. Provision may still be made to protect treatment plants
against accidental or illegal discharges of high strength waste
or toxic materials. The biological processes are most subject
to impact by such discharges. Protection may be provided in the
form of plant flexibility - the sludge re-aeration mode provides
a reservoir of micro-organisms protected from main stream tox-
ics; or in the form of dual units - multiple anaerobic digesters
fed individually reduces the potential for upsetting all units
under one shock load. Generally, however, such provisions are
relatively low in cost. It is not usual to provide major facil-
ities to cope with infrequent, irregular events.
17
-------
Plant Location and Site Conditions
Traditionally, treatment plants have been located adjacent
to the point of final effluent disposal, and close to the served
customers. Most large plants are located on shorelines and
riverbanks. As a result, our water pollution control programs
have located treatment plants in fully urbanized areas, on
waterfront property, in generally poor soil conditions. With
recent emphasis on wastewater reuse, this traditionally located
treatment plant is remote from areas of potential reuse. If
plant expansion/upgrading is carried out at existing sites,
additional costs are often required to ensure added features are
publically acceptable. Examples are identified in Table 3.
Conversely, location of facilities remote from urbanized
areas, whilst avoiding some of the costs identified below, may
present new areas of high cost and environmental problems which
must be evaluated. The location of existing facilities is
generally a result of logical evaluation of conveyance costs at
the time of original conception. Construction cost of major
trunk sewers, or force mains to convey sewage to a new site may
often be greater than the cost of provision for necessary
TABLE 3. SITE LOCATION—CONSTRUCTION COST IMPACTS
Site location
Additional facilities
required
Additional
costs, %
Residential area
Waterfront
For poor soil,
conditions
Covered units, odor
control, aesthetic
treatment
Public access to water-
front, aesthetic
treatment
Piled foundations
5-20
5-10
5-10
* City of Olympia, Washington
t West Point treatment plant, Municipality of
Metropolitan Seattle, Washington
18
-------
facilities at an existing site. Environmentally, new site loca-
tions are inevitably sensitive, and the question of encouraged
development pressure along the line of a new trunk system is
often a point of concern.
Consultant Fee Structure
Up until the promulgation of P.L. 92-500 the fee curves
published in ASCE No. 45 provided the basis for the negotiations
for consulting engineer's charges. The charge was based on a
percentage of construction cost, the percentage varying accord-
ing to total project cost. A variety of adjustment factors
could be applied to tailor the fee to the project in question.
Since the fee was directly related to construction cost, the
engineer's integrity stopped him from increasing his fee by
increasing the project's cost. As a result of the new EPA
consultant procurement requirements, the consultant's fee is
negotiable at the start of the contract with the scope of the
consultant work being the basis for his estimated cost, and
from this his profit or fee.
On the face of it, the new approach should be a fairer
system. However, due to the introduction of the client/consult-
ant fee negotiation phase the system is now open to price
shopping as opposed to just quality shopping as under the old
system. It also opens up the specter of the practice of
"buying" jobs as happens in the construction field; i.e., the
final price is not the initial figure, but includes an ad-
ditional substantial amount resulting from legalistic scope of
work interpretations and subsequent contract claims. Consult-
ants and contractors expressed serious concern that trimming
design fees and selection of consultants on price without regard
to competence will result in increased final contract costs
exceeding any potential savings accrued in the design phase. A
proposal for construction contract change order cost history of
a consultant to be evaluated during selection procedures is in-
cluded in Section 4.
Convention of Engineering Practice and Procedure
Engineering is not a pure science. Engineering theory pro-
vides a guide to which the engineer then applies his and the
industry's experience to finalize the design. Thus, by its very
nature engineering tends to be conservative. Refining designs
would result in some cost savings. However, additional costs
arise from refinement of specific designs; for example, pilot
studies may be undertaken to optimize unit sizing criteria for
a given treatment plant.
Maintaining information transfers between the engineering
community and research and academic institutions through their
technical organizations reduces the effects of engineering
19
-------
conservatism. The conservatism ensures that the acceptance of
promising new technologies will be limited until such time as
they are proven.
Deviation from this conservatism, specifically in the areas
of sludge processing, has resulted in some very costly mistakes.
Several installations of sludge incinerators, sludge drying
equipment and, more recently, sludge heat treatment systems
stand unused today as mute evidence of the dangers in departing
from well-proven technologies.
Standard Design Requirements
In the area of standard design requirements, there are two
opposing viewpoints. On the one hand, "standards" are promul-
gated within regulatory agencies in belief that unsuccessful
projects will be eliminated if the standards requirements are
observed. They reason that both over and underdesign will be
prevented by this action. Conversely, the view of the special-
ist engineering consultant is that standard design requirements
prevent innovation; result in overdesign, thus higher cost; and,
most seriously, may result in project failures and deficiencies
if blind acceptance of design data results in inadequate con-
sideration of actual circumstances.
Pilot studies are sometimes used to develop more specific
design criteria. These are usually justifiable for only large
scale projects where substantial capital, and operations and
maintenance cost savings may be anticipated. Otherwise, infla-
tion over the time delay involved may consume potential cost
reductions. A stronger case can be made for pilot studies where
such work is needed to prove out methods as applied to different
wastes or where more conservative designs cause non-financial
impacts as well.
To design a facility for which neither good operational
data nor pilot plant data are available the engineer must make
many decisions based on assumption. If he assumes a conserva-
tive point of view large sums of money may be expended on a
design with unnecessarily large capacity. Currently, if the
engineer uses design data which would result in less capacity,
he runs the grave risk of liability with no benefit to himself
and little to his client.
A simple example of using optimum design data to minimize
the cost of construction follows: Consider primary sedimenta-
tion tankage for a given facility. A "standard design" figure
would be an overflow rare of 0.38 L/S/m2 (800 gal/day/ft2)3.
Assume an arrangement whereby 4 tanks each 27m diameter (72')
would be provided for this design. Now consider the situation
in which the engineer believes that a higher overflow rate may
well prove acceptable. Suppose a rate of 0.51 L/S/m2 (1,070
20
-------
gpd/ft2) is felt applicable, with 3 of the 4 tanks referenced
above to be constructed. The design data is set forth In Table
ail n^ hat in-thS 3 tank situ*tion the engineer has made
tiL^n Y Pr°V1*10ns for the addition of a fourth tank, and,
tn So? n' n° *lc?niflcant engineering cost savings are realized
in designing three rather than four tanks. Under these condi-
tions the cost of constructing a fourth tank under a separate
contract would be around $170,000.
Now let us review the financial situation outlined in
Table 5. The engineer will save $12,000 for his client. Regu-
latory agencies, with minimal direct involvement in the decision
making process, stand to save approximately $100,000. In the
event that during initial plant operation the need for the
fourth tank is identified, the Municipality might well be re-
quired by the regulatory agencies to construct the additional
facility with no grant funding and cost to the city of $170,000.
TABLE 4. COMPARATIVE COSTS OF SEDIMENTATION TANKS
Plant flow
Tank overflow rate
Tank diameter
Number of tanks
Cost*
Conventional design*
Metric
570 1/s
0.38 1/s/m
22 m
4
$615,000
English
13 mgd
800 gpd/ft
72 ft
4
$615,000
Optimum design
Metric
570 1/s
0.51 1/s/nT
22 m
3
$505,000
English
13 mgd
o
1,070 gpd/ft
72 ft
3
$505,000
* Based on data from Areawide Assessment Procedures Manual, Report EPA-600/9-76-014,
July 1976, Appendix H.
21
-------
TABLE 5. COST APPORTIONMENT
Agency share*
EPA (75%)
State (15%)
Municipality (10%)
TOTAL
Conventional
design
461,000
92,000
62,000
615,000
Optimum
design
379,000
76,000
50,000
505,000
Difference
82,000
16,000
12,000
110,000
Assumed distribution, proportions vary state to state.
To recapitulate:
1. Regulatory agencies would stand to gain $90,000 and
lose nothing.
2. The Municipality would stand to gain $12,000 and lose
$170,000.
Nevertheless, engineers continue to provide the most cost-
effective solution, even if this involves going outside
"standard" design limits occasionally. Obviously, regulatory
agencies, who stand to gain the most financially from optimum
design, should actively encourage both Municipality and Engineer
by eliminating the disincentives outlined above. Section 4
includes a discussion of supplemental Step 3 grant funding to
cover a situation where the engineer has indicated to EPA during
Step 2 that abnormal design data are being adopted. This pro-
vision reflects innovative technology provisions of the 1977
Amendments to P.L. 92-500.
Acceptance of New Design, Methods and Materials
The incentive for acceptance of new ideas is that they may
either reduce cost and/or improve performance. Since conserva-
tism prevails in the wastewater field, acceptance of new designs
requires substantial support from all members of the team:
regulatory agencies, designers, clients, equipment suppliers,
and contractors. Economic incentive, the prime mover in accept-
ing new ideas, is direct for the grantor, client, equipment
22
-------
supplier and the contractor, while it is indirect or even nega-
tive for the designer, who is responsible for specifying new,
lower cost design. Recognition and resolution of the negative
position of the designer is essential if the full benefit is to
be obtained from new developments. There ought to be more in-
centive for the engineer to develop and use new design ideas.
Design for a Maximum of Prefabrication, Precasting, Standard-
ization
All contractor's personnel and all consultant's construc-
tion personnel interviewed express the opinion that cost saving
could be obtained by maximizing use of prefabrication and pre-
casting. Contractors often saw potential saving in contracts,
but were unwilling to adopt the lower cost methods because the
burden of redesign was placed on them. To maximize savings
potential the original designer must, from the earliest stages,
incorporate concepts of prefabrication/precast techniques into
the design.
Both contractors and owners were concerned about special-
ist; nonstandard items that were specified in the design when
"off-the-shelf" items would have served the same purpose.
Degree of "Openness" or "Tightness" of Specifications
Contract specifications provide the pathway from the design
to the completed contract. Together with the contract drawings
the specifications form the legal documents on which the con-
tractor bases his bid. Once bids are accepted, these documents
provide the designer and the client with legal backup in case of
any inadequacies in the product due to contractor's irresponsi-
bility, and the contractor with similar controls over his sub-
contractors and suppliers.
An "open" specification is one where the Contractor is in-
formed of the end results he is to achieve in the finished pro-
duct, as well as the quality control specifications for materi-
als used in its construction. The Contractor is free to choose
by which method he will arrive at the end result. Naturally, he
chooses the method rrost economical to himself. However, pro-
vided it is clear at the time of bid that this freedom of choice
exists, he will pass some or most of the savings on to the owner
at the time of bid.
A "tight" specification dictates to the contractor pre-
cisely what he is to provide, whether as a construction sequence
or in the purchase of equipment. This restricts the contract-
or's ability to use his construction experience "know-how , and
his ability to use available equipment is prejudiced. In equip-
ment purchase his biggest cost reducer, bargaining P°wer, is
severely curtailed. From the owner's viewpoint, tight
23
-------
specifications provide him with easy assurance of quality, al-
though at a potential cost premium.
It must be made clear that "open" specifications do not
imply incompleteness. Nor is an "open" specification an abro-
gation by the engineer of his responsibilities. It is a method
by which the contractor can apply his unique combination of ex-
perience, manpower and equipment to provide the most economical
solution for a given problem. An example is the construction of
a deep pumping station in wet ground. One contractor, equipped
with equipment and knowledge for well point dewatering from a
previous project, may be able to offer a competitive price for
a cast-in-place structure. Another, without such equipment, may
be able to construct a caisson more economically. A "tight"
specification around one or the other method has obvious limi-
tations over an "open" specification defining the finished pro-
duct only.
"Open" specifications require care'ful preparation by the
engineer. If alternate schemes are proposed by contractors,
detailed evaluation of their feasibility is often necessary.
Tight specifications are most economical for the engineer to
prepare. When pressure is applied to the engineering profession
for competition on a fee basis, the net value of open vs. tight
specifications and similar practices must be taken into account.
Effect of "Or Equal" Clause
The concept of specifying mechanical equipment using at
least two manufacturers names and the words "or equal" is now
generally accepted. One remaining exception exists; agencies
are permitted to standardize new equipment with existing opera-
tional units, for the purpose of simplified maintenance. In
addition, cases occur where the engineer knows of no equal to
the particular equipment desired. Provided this is document-
able, EPA will accept single source supply.
The viewpoint of equipment suppliers is that the present
system does not sufficiently protect reputable manufacturers
from suppliers who succeed in meeting the letter of the speci-
fication while still producing substandard equipment. We accept
this, but, rather than returning to past methods of bidding, we
feel this is best guarded against by tightening specifications
as necessary. In most instances, the more experienced consult-
ing firms have developed their own standardization of specifica-
tions which prevent substandard equipment substitution.
Contractors point to the occasional yet continuing use of
proprietary specifications where no reasonable alternative is
available, or where proprietary patented items are called for,
or where relatively unimportant features are required that are
standard for one manufacturer yet non-standard and expensive for
24
-------
competitors to provide. One example cited to us by a manufac-
non^pf af! ^° an-item °f ind*strial machinery specmSd S a
wh^h r*latjd Project. The owner required certain features
which restnct the contractor to purchasing from one manufac-
turer. Quoted cost was $90,000. The contractor was also in-
volved in a similar project in another state requiring identical
equipment. Here competitive, or "open", bidding was permitted.
The same manufacturer who quoted $90,000 on the first project
was low bidder on the second project at a bid price just under
$50,000.
More generalized information quoted by a construction
contractor was as follows:
Number of Bidders Cost as %
6 or more 100
2 120
1 up to 200
As associated cost item to contractors (and ultimately,
therefore, to EPA) is a provision in contracts that suppliers
be listed with the bid and not be changed without the consent
of the owner. Contractors argue that this enables suppliers,
who have given a firm price at bid time, to refuse to accept all
of the terms of the contractor's contract with the owner, such
as warranty requirements or spare parts, which will then be
charged as extras if the Contractor's negotiating position is
eliminated. Conversely, suppliers argue that "bid shopping" by
the contractor cheapens the equipment supplied by forcing a
lower price on the supplier.
Engineer Liability
Concern about engineer liability is one more factor in the
maintenance of engineering as a conservative profession. The
desire to limit their liability has inhibited engineers from the
initial acceptance of new ideas without the benefits of proven
installations. Sharing of this liability by clients and/or
funding agencies where new and/or improved methods appear cost
attractive will encourage their implementation and potential
cost savings.
Regulatory Agency Cost Reduction Programs
The EPA, in recognition of the escalating costs of achiev-
ing the goals of P.L. 92-500, has instigated two specific pro-
grams in addition to their normal review roles. Namely, Value
Engineering and utilization of Corps of Engineers staff for
construction inspection duties.
25
-------
Value Engineering is a technique developed originally by
the General Electric Company and subsequently adopted by the
military establishment and the Corps of Engineers. Value
Engineering is a systematic approach to obtaining optimum value
for money expended. The EPA has made value engineering manda-
tory at the Step 2 design phase for all projects exceeding $10
million. Review of value engineering analyses conducted as part
of the EPA mandatory requirements shows documented cost savings,
in addition to functional improvements. It was the opinion of
all value engineers interviewed that even greater cost savings
could have been achieved if the value engineering had been con-
ducted at the Facilities Plan Step 1 phase allowing the address-
ing of basic concepts. Although this is not official EPA policy,
in a few cases Step 1 value engineering4 has been funded by EPA.
To provide close inspection of the construction phase the
EPA has contracted with the Corps of Engineers to provide con-
struction inspection personnel. Both owners and design consult-
ants were concerned that transferring inspection responsibili-
ties to an outside agency would result in EPA staff being even
more remote from real world problems, and thus costs of con-
struction. Other concerns were expressed relating to the re-
sponsibilities of inspection personnel making construction re-
lated decisions. It was the opinion of designers and contrac-
tors that the additional inspection layer would not reduce con-
struction costs, and could result in overall cost increases due
to the inclusion of an additional administrative layer.
Grant Funding Eligibility
Public Law 92-500 provides grants of 75 percent of eligible
project costs, not total project-costs. The decision of project
eligibility is made at the local EPA level by EPA staff specifi-
cally assigned to the project. Eligibility rules and guidelines
have been promulgated since the inception of the grant program
to provide guidance to both owners and regulatory agency person-
nel alike. However, final eligibility is based on the judgment
of the local reviewers. Because of the differing interpreta-
tions, inequities have resulted between different owners.
Owners and designers quoted examples of eligibility decis-
ions not being finalized until completion of contract drawings.
(Indeed, EPA is not committed to make final eligibility deter-
minations until final audit stage.) The delay of eligibility
determination has resulted in higher than expected local costs,
and then subsequent delays while non-eligible items were either
modified or deleted to match the locally available funds, or
while arrangements for revised fundings were made. The cost of
delay can exceed the original "non-eligible" items. It was sug-
gested that project eligibility should be determined and agreed
upon, in writing, by all parties at the 10 percent design stage.
26
-------
Contract Programming Techniques; Turnkey. Fast Track Pre-
Ordering ~~ ~ ——
The majority of wastewater contract funded under P.L. 92-500
are implemented in a series-stepped fashion consistent with the
3-step grant program. Contracts are awarded for each step with
specific contractor responsibility ending on the termination of
that step. This approach is shown schematically in Figure 3.
Problems of this type of bidding include: delays between
steps; difficulty in identifying who is responsible in the case
of errors; and at the end of the project the owner has no
guarantee of plant performance.
Suggestions made in interviews by owners, consultants and
contractors to address shortcomings of the existing system were
to consider the forms of contracts used by industry for con-
struction of process and waste treatment facilities, namely
"turnkey" and "fast track".
Turnkey—
Contractually "turnkey" provides the owner with a complete
service from detailed design through construction and startup.
Turnkey projects normally guarantee performance of the product.
Only a few larger U.S. design/construction companies are at
present offering such services, because of the greater risk in-
volved in this type of contract. However, one of the con-
tractors who was contacted expressed interest in creating joint
ventures with established consultants to offer "turnkey" serv-
ices. Engineers and many municipalities have always been anti-
turnkey due to the difficulty in obtaining specification and
quality control by the owner.
Fast Track—
The major feature of "fast track" technique is the over-
lapping of the Step 2 and Step 3 phases. Responsibility of
administering the Step 2/3 phase is assigned to a contract man-
ager. Advantages of this technique are:
1. It compresses the design/construction period.
2. Eliminates owner from designer/contractor conflicts.
3. Owner and funding agencies only have to deal with one
area of responsibility — the contract manager.
The fast track approach can have the very serious disad-
vantage of removing the owner from the decision making process
as regards to design features and quality of construction.
Another bid area identified that has potential for cost
savings is in flexibility for pre-bidding major equipment items.
27
-------
OWNER
FUNDING/
REGULATORY
AGENCY
"X s' \
\ /• i
./ \ i
^ ^. i
DESIGN
CONTRACTOR
\
CONSTRUCTION
CONTRACTOR
TRAINING
O&M MANUAL
I
INSPECTION I
I
WARRANTIES
CURRENT PRACTICE
TRAINING
O&M MANUAL
WARRANTIES
FUNDING /
REGULATORY
AGENCY
CONTRACT
MANAGEMENT
I DESIGN
| CONTRACTOR
r
•-1
L_
CONSTRUCTION
CONTRACTOR
FAST TRACK
OWNER
FUNDING /
REGULATORY
AGENCY
TURNKEY
CONTRACTOR
DESIGN
CONSTRUCTION
START-UP
TURNKEY
FIGURE 3. CONSTRUCTION MANAGEMENT ALTERNATIVES
28
-------
This approach can address two areas:
1. Where equipment delivery time exceeds contract time.
2. Where selection of a specific equipment allows opti-
mization of building space and ancillary equipment.
Time of Year Contract is Bid
The significance of bid timing on cost is determined by the
question - "on contract award can the contractor proceed direct-
ly into his normal construction schedule?" Any bid period that
is not synchronized to the contractor's ability to build will be
reflected in the bid price. Seasonal influences on job charac-
teristics are summarized in Table 6. Actual cost impacts iden-
tified in Table 6 will vary with specific area construction
seasons. Contracts in southwest states with minimal winter
disruption will have less cost significance if bid outside nor-
mal bid periods.
TABLE 6. IMPACT OP TIME OF YEAR OF BID
Type of job
Earthwork,
subgrade
Earthwork,
subgrade
Superstructure
Superstructure
Equipment
installation
Equipment
installation
Construction
period
One year
or less
Multi-year
One-year
Multi-year
One-year
Multi-year
Favorable
bid time
Start of
construction
season
Start of
construction
season
Start of
construction
season
Start of
construction
season
End of
construction
season
Any time
Rationale
Construction sensitive
to groundwater and
weather conditions
Construction sensitive
to groundwater and
weather conditions
Construction sensitive
to weather
Construction sensitive
to weather
Contractor has low
work orders and is
not restricted by
weather
Weather is not a
factor
Cost
impact
High
-W
Medium
Low
Medium
29
-------
As an example, a six month earthwork subgrade contract re-
cently bid at the end of the regular construction season for
Corvallis, Oregon resulted in a bid of approximately 17 percent
over the price that was subsequently obtained for the start of the
next construction season after the first bid had been rejected.
Bid; Periods, Times (Other than Calendar), Types
The primary objective of the competitive bidding process is
to obtain a prespecified product at the least cost. Rules,
regulations and procedures related to the bidding process have
the objective of making the process honest and of eliminating
unfair advantages.
Current practice is to inform potential bidders by adver-
tisements in trade journals and personal contacts. Lead time
before bid openings varies from 4 to 12 weeks depending on job
size and complexity. Sealed bids are received up to a pre-set
time and then opened in public. On opening bids are checked by
the client's representatives and funding agencies to ensure the
potential low bidder is responsive to numerous bidding require-
ments; such as performance bonding, insurance, affirmative ac-
tion, relationships with equipment suppliers and subcontractors.
Any irregularity is normally considered non-responsive to the
bid and disqualifies the bidder.
Lead Times—
All contractors were content with bid periods provided on
EPA funded construction projects. It is normal practice for
contractors in competitive situations not to arrive at a bottom
line price until a few minutes before the bid deadline. Con-
tractors expressed the desire that the bid deadlines of similar
contracts within an area should be coordinated by owners and
their consultants to minimize overlapping bidding periods; for
smaller jobs by state, and for large jobs by region (e.g., West
Coast). Few contractors maintain large estimating staffs and
normally bid a job by utilizing staff from ongoing construction
jobs.
Bid Type—
In an attempt to obtain the lowest price a number of bid-
ding methods have been adopted including lump sum, unit price,
and itemized major equipment plus lump sum. Supporters of the
unit price method claim that bid unit rates provide the basis
for subsequent contract change orders as opposed to the lump sum
method where all prices have to be negotiated. Contractors were
shown detailed "bill of quantities" bidding lists as prepared
for European construction contracts to compare with lump sum
North American documents. Their opinion was that bid prices
would not be lower with this type of bidding approach.
30
-------
Time Duration Allowed for Construction
Traditionally the responsibility for selecting the duration
of a specific contract is with the designer. The allowable con-
tract time is identified in the contract bidding documents,
along with liquidated damages that will be assessed by the owner
for each day required for project completion beyond the allow-
able period. The degree of difficulty/risk in completing the
contract will be reflected in the contractor's price.
Contract periods are often selected on the basis of empiri-
cal rule of thumb methods based on the estimate of contract cost
and previous experience. Contractors and/or construction con-
sultants also provide useful inputs.
Deviation from this practice, in the wastewater field,
would be when the city is required to meet specific effluent
quality limits at a date earlier than would be required for con-
struction in normal circumstances. Any compression of the con-
tract period that involves regular overtime, shift work and
overlapping of trades will increase contract costs. Of those
contractors who were willing to offer a cost penalty the range
ventured was 0 to 10 percent.
The contract time allowed should take into account the time
of the bid, since jobs that are bid at the end of the construc-
tion season will normally be unable to start until the next con-
struction season. For smaller short-term contracts this could
drastically reduce the available working time within the allowed
time frame. An additional factor to be considered in bid time/
contract duration is the time of year the contract will be com-
plete to allow plant startup and testing. For severe weather
conditions (specifically cold), problems with freezing can delay
startup/testing through to the next construction season. The
difficulties related to winter startups will be reflected in the
bid price.
Contractor's Reaction to Inspection Requirements and Methods
Within a specific region, owners, architect/engineering
consultants and contractors build up a reputation. Contractors
are very aware of owners particular areas of concern, consult-
ants contract documents and their inspectors interpretation of
those contract documents.
In interviews with contractors, each contractor quoted
specific owners and engineers, who in their experience, either
made the work easier or more difficult. To obtain the lowest
bid for a specific job it was the contractor's opinion that con-
tract documents should be clear, free of loose interpretations,
and that inspectors interpretation of the documents should be
consistent as well as flexible where final product quality was
31
-------
not affected. Contractors quoted increases of one to five per-
cent on their bid prices in anticipation of difficulties with
particular contracts.
Prevailing Labor Rates Including Government Requirements and
Regulations
A requirement of all EPA funded projects is that contract-
ing staff be paid union wage rates applicable to the contract
location. Other government requirements include worker/public
health and safety standards, affirmative action, environmental
constraints (noise, air pollution, etc.), and detailed reporting
requirements to allow policing of the rules and regulations.
Union contractors by definition pay union rates; only non-
union contractors have the option to pay less than union scale
wages. In discussions with non-union contractors they indicated
that their pay scales equal or exceed union rates. Thus there
did not appear to be any cost saving by eliminating the minimum
wage scale requirement. The non-union contractor competitive-
ness is due to his greater work force flexibility, not lower
pay.
Other government requirements such as the reporting re-
quirements do impose a cost burden on the contractor. For a
small job the additional staff required to satisfy these needs
can represent up to 5 percent of project cost.
Magnitude and Distribution of Labor Skills
Construction of wastewater treatment facilities requires
specific contractor experience, however it does not require
specialist skills outside the range provided by contractors in
their other contracting business. Generally, contractors within
an area have no problems hiring the necessary skilled labor.
Contracts that exceeded the capabilities of local contractors
would, by virtue of their size, attract regional contractors
with the hiring power required to undertake the work. Contract-
ors interviewed did not see the labor skills market as a signi-
ficant factor in their bid price.
Distribution of Construction Trades Required
Modern treatment plants can involve a complete range of
construction skills. The more complex the design the greater
the number of disciplines required. Contractors did not feel
that this was an item that had significant impact on contract
prices. Most contractors import most of their labor so their
bid prices already include costs for employee travel time and
per diem expenses.
32
-------
For examn^n n^K** d° COimnand hi^her renumeration than others.
For example, plumbers earn more than iron workers. However, by
reaardl^S of wastewat?r facilities, certain skills are required
regardless of their relative cost. Cost savings will always be
made if the design provides for simple, fast construction re-
gardless of the trades involved.
Effect of Labor Negotiations for Rates, etc.
Labor contracts are for discrete periods of one, two and
three years depending on the specific trade. There is not a
common period for contract expiration; the dates of each trade
reflect historic events. Thus for most contracts at least one
of the involved trades will be involved in negotiations for a
new contract, which in all past cases, has resulted in an in-
crease in base wages or benefits or both.
The contractor, when preparing his bid, has to make an
estimate on what he thinks the increase will be and develop his
price accordingly. An alternative to letting the contractor
estimate the increase, which could result in either overcharging
the owner or reducing the contractor's profit, is to introduce
escalation clauses into the contract. This would allow the bid
price to increase by the amount of the increased costs resulting
from the new contract. The majority of contractors opposed this
alternative as being inflationary, as well as taking away their
ability to make their own judgement.
It was the contractor' s opinion that they have a close feel
of what the increases will be, and, as such, future labor nego-
tiations do not result in bid padding to cover unexpected costs.
Size of Project, Level of Competition
Every contractor has a preferred contract size range. The
lower limit of the preferred range is governed by overhead;
generally the smaller the contractor the lower his overhead rate.
A large contractor is, therefore, at a cost disadvantage to a
small contractor when bidding small projects. The upper limit
of contract size is defined by the bonding limit of the contrac-
tor. This upper figure does vary with amount of work under con-
tract, which defines tied bonding capacity. As an example, a
mid-sized general contractor specializing in water/wastewater
construction may bid competitively on projects between $1,000,000
and $15,000,000.
Some contractors extend the upper limits of their bonding
capabilities by the formation of joint ventures with other com-
panies. For example, bids for a major regional wastewater
treatment plantS (low bid $147,500,000) were received from six
bidders, five of whom were joint ventures and the other being
a co-partnership.
33
-------
In general, contractors felt that competition at all levels,
over say $1,000,000,was adequate; in the event that more compe-
tition is needed in any area it is automatically provided by the
industry itself. For smaller contracts, conflicts with peak
summer construction should be avoided.
Equipment Cost and Availability - Standard Equipment
With the exception of sewer systems, all wastewater facili-
ties include at least one item of purchased equipment. To the
contractor, equipment involves four basic costs, namely:
1. equipment purchase,
2. equipment storage prior to installation,
3. equipment installation, and
4. equipment startup and testing.
The specific contribution of each cost element on the in-
stalled equipment cost will vary widely with the specific equip-
ment item. For complex, close tolerance equipment the initial
purchase price will represent the greatest cost, where as for
lower cost equipment startup and testing could represent the
greatest cost.
Equipment Purchase—
For all bidding conditions the contractor is free to shop
the market to obtain the least cost; except for bids requiring
the prices of major equipment items, and where no "or equal"
provision is made. In many cases this is a lower cost than the
contractor used in preparing his original bid. The lower cost
the contractor obtained, he did so by virtue of his position in
the equipment manufacturing industry's market. The exchange
that takes place at that time is an expression of the contrac-
tor's role in the economic system; that being the owner's agent
for buying equipment. As a result of this, owner-contractor
relationship, cost saving is not directly passed on to the
owner.
Equipment Storage Prior to Installation—
Most equipment is sensitive to the elements and requires
covered storage. Certain equipment requires storage in a con-
trolled atmosphere. Storage is a cost to the contractor. The
option of storage at the place of manufacture, or off-site in a
warehouse, is often precluded as payment on the equipment will
only be made on delivery at the site. For sensitive large
equipment pieces storage costs can be significant; for example,
$0.20/cubic feet per month.
34
-------
Equipment Installation—
Equipment installation is the emplacement of equipment in
its proper position and in working order prior to plStlSrSp.
*nrt Sint?;011. inV°1VeLSeCUring the piece of equipment to a base,
and then hooking up the appropriate process piping, power and
instrumentation lines. The more complete and self contained the
equipment, the less work and cost there is for the contractor
Care ought to be taken to specify controls normally supplied as
a part of the equipment in order to save unnecessary costs.
Equipment Startup and Testing—
Equipment manufacturers usually provide some startup as-
sistance; such as an on-site representative, training, manuals,
and slide and topic shows. The further cost of these services
is included in the purchase price. Startup and testing time can
be reduced to a minimum by standardizing such ancillary control
equipment as motors, equipment power drains, controllers, alarm
systems, and instrumentation.
Any disruption of the contractor's normal construction
sequence will involve increased costs. Due to the rapid in-
crease in demand for wastewater control equipment difficulties
were being experienced in obtaining deliveries within the con-
tract period. Fortunately, delivery problems and long lead
times experienced two and three years ago are being reduced as
manufacturers increase their production capabilities. However,
any large electro-mechanical piece of equipment will require a
long lead time. This is especially true of one requiring inter-
facing with safety and control instrumentation devices, and
control panels. Examples of long lead items are: large
electric motors; engine drives; turbines; dewatering equipment,
such as centrifuges, filters and presses; chemical oxidation
systems; and computer systems. For these items prerequisiting
long delivery times, pre-ordering addresses directly the problem
of disrupting the construction schedule.
Equipment Supplier Bidding Requirements - Subcontract and
General Contract Aspects
Under existing bidding operations guidelines the owner may
require at the time of the bid, the identification of the manu-
facturer of specified equipment and its price. Equipment manu-
facturers generally prefer the inclusion of the identified manu-
facturer requirement because it prevents the contractor from
equipment shopping after he is awarded the contract. Conversely,
contractors prefer no listing. They claim that post bid shop-
ping enables them to obtain the lowest price possible for equip-
ment. General contractor opinion was that full flexibility
should be given to the contractor in his dealing with equipment
suppliers and subcontractors, commensurate with his overall
contract responsibilities.
35
-------
Competition in the Construction, Equipment and Suppliers Markets
Stock market analysts, industrial marketing experts, con-
tractors and members of the sanitary engineering community pro-
jected the increase in demand that the passage of P.L. 92-500
would have on designers, suppliers, contractors and equipment
manufacturers. The increase in production and product range has
been in concert with increased demand. Consequently, even with
high demand, competition within the industry has increased.
However, there are exceptions to this; for example, motor con-
trol panels. The effect of competition in the market place is
to encourage efficiency and thus lower costs.
Use of CP, PERT by Owner and Contractor
To meet tight deadlines major military contractors during
the '40s and "50s developed sophisticated "critical path" or "pert!1
techniques for programming job progress. These sophisticated
methods are being used in ever increasing number in the imple-
mentation of wastewater projects. In some cases they are pre-
pared by the owner and in other cases by the contractor.
Most contractors did not use "Critical Path" or "PERT"
techniques as they were not compatible with their needs. Con-
tractors preferred and used simpler techniques. And if CP or
PERT systems were required as part of the contract it became an
additional overhead cost with little, if any, benefit. Concern
was expressed by some owners that contractors were using the
CP/PERT program as a claims tool. Any action by the owner or
his representative that could be interpreted as a modification
to the CP/PERT program was considered justification for a delay
and thus cost claim.
Owners and contractors alike agreed on the need for a com-
mon planning method. However, to be useful and thus have cost
saving potential it must be designed to address the needs of the
wastewater contractor, not just copied from some other industry.
Change Order, Construction Delays
Most owners set aside a certain amount to cover change
orders. The amount can vary from 1 to 20 percent dependent on
the type of job. Procedures for the instigation of a contract
change order are included as part of the contract bid documents.
What is not included is the cost of the change order. This is
customarily negotiated individually between the owner's repre-
sentative and the contractor. Change orders can either reduce
or increase the scope of work and thus the contract price. For
increased scope of work a change order has two costs; one re-
lated to the additional work, and the other is potential delay
caused by disruption of the contractor's schedule.
36
-------
Excluding "turnkey" contracts the best way to reduce the
number of change orders is to provide sufficient Step 2 design
time and utilize competent experienced design contractors. An
investigation of contracts let by a major sewerage utility6 over
10 years indicated that change orders represented 15 percent of
their completed facility costs.
SUMMARY OF NON-STRUCTURAL FACTORS
The potential impact of non-structural factors on final
construction costs was described under twenty-nine sub-headings
in the previous sections. The impact of these items on influ-
encing construction costs are identified in Table 7. Specific
recommendations for implementing changes in areas that have a
significant impact on construction costs are identified in
Table 7 and described in depth in the next Section.
37
-------
TABLE 7. IMPACT OF NON-STRUCTURAL FACTORS
Item
no.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Non-structural item no.
Effluent limitations
Pre-grant, post-grant time delays
Source control
Plant location
Consultant fee structures
Conventions of engineering practice
Standard design requirements
Acceptance of new design ideas
Design for pref abrication/standardization
Specifications strictness/looseness
Effect of "or equal" clause
Engineer's liability
Regulatory agency cost reduction program
Grant funding eligibility
Construction management alternatives
Time of year contract is bid
Bid - period, times and type
Time duration allowed for construction
Contractor perception of inspection requirements
Prevailing labor rates
Magnitude and distribution of labor skills
Distribution of construction trades
Effect of labor negotiations
Size of project
Equipment cost
Equipment supplier bidding restrictions
Competition in construction and equipment field
Use of CP, PERT scheduling tools
Change orders, construction delays
Construction cost
change (%)
<5
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
5-10
•
•
•
•
•
10-20
•
>20
•
38
-------
REFERENCES
1. Amendments passed by Congress in December 1977 provide some
flexibility for marine discharges.
2. An Analysis of Planning for Advanced Waste Treatment
(EPA 68-01-4338).
3. Areawide Assessment Procedures Manual, Appendix H.
4. City of Anacortes, Washington.
5. Regional Wastewater Treatment Plant, Sacramento Regional
County Sanitation District.
6. Municipality of Metropolitan Seattle, Washington.
39
-------
SECTION 4
PROPOSED NON-STRUCTURAL SOLUTIONS
PROCEDURAL OR OTHER NON-STRUCTURAL ASPECTS
Section 4 presents a series of proposals for EPA considera-
tion which are aimed at procedural and other non-structural as-
pects of the wastewater facility construction grant program.
Many of these proposed solutions are derived from conclusions
developed in Section 3. In some instances, direct'EPA action
would be appropriate. In other instances, further research work
should be considered before proposed solutions are implemented.
The principal focus of recommendations is cost reduction in
the construction phase of the grant program, which is the main
consideration of this portion of the study. Other factors are
also referenced in the text. These other factors are considered
since they can be as important as capital cost reduction alone.
Proposals are ordered to follow approximate chronological se-
quencing through the project stages of planning, design, bid,
and construction.
RECOMMENDATIONS
Expansion of the Planning Phase
The federal grant program supporting construction of waste-
water treatment facilities is one of the larger federal public
works programs. Although control of water pollution is the
principal objective of this program, there are many other goals
and objectives tied to it. Some of these, like the requirement
for industries to bear .the cost of treating their own wastes,
are imposed by P.L. 92-500 itself. Further goals and objec-
tives, such as environmental impact or equal opportunity and
fair wage rate requirements, are imposed by other federal laws.
State and local laws, regulations and related policies may im-
pose requirements in addition to those found in federal rules.
Finally, it may be convenient and desirable to plan multi-
purpose facilities in order to economically achieve several
related objectives. Examples of such common multi-purpose
projects range from the development of recreational facilities
40
-------
and open space corridors along rights of way, to the generation
of electrical power using sewage solids and municipal refuse as
ZU.G X •
Project Implementation Plan—
Because of the need to comply with the myriad of legisla-
tive and procedural requirements, even the smallest projects
would be expedited by the development of a clear concise project
implementation plan. This project implementation plan should be
developed as soon as possible after a decision is made to pri-
oritize a project for funding. A three-part recommendation has
been formulated to meet this goal. Although the first part of
the recommendation is most important, each added part would en-
hance the workability and effectiveness of the recommended ap-
proach:
1. A project implementation plan should be developed as
soon as possible after a decision is made to place a
project on state priority list for funding. This plan
should include: (1) a clear description of each
federal, state and local requirement which must be
complied with to plan and construct the proposed fa-
cility and place it into operation; (2) for each such
requirement, a description of the project features,
activities, reports, public hearings, etc. that will
be undertaken to comply with the requirement; and (3)
for each activity, report, hearing, etc. identified,
the assignment of responsibility, timing, budget and
source of funds to accomplish it.
2. Costs for project features and implementing activities
should be distributed equitably according to the na-
ture of the requirements and purposes to be achieved.
3. Maximum flexibility should be preserved for grantees
to plan multi-purpose projects to meet local needs by
encouraging incorporation of compatible projects with
the facility plan which can be associated with pollu-
tion control efforts, and therefore, receive added
community support; examples,
recreational facilities, open space corridors and
energy recovery projects using municipal refuse and
sewage sludge s.
As previously indicated, the second and third parts of the
recommendation are separable.
It should be emphasized that the project implementation
plan would not be a conclusive document like an Environmental
Impact Statement. Rather, it would be a working plan, setting
forth (among other things) what NEPA requirements are, and how
such requirements would be complied with during the taciiity
planning phase.
41
-------
Cost Saving Features—Several cost saving features would
occur as a result of adoption of this recommendation. The first,
and most important, is that the project would be placed on a
critical path implementation schedule. This would act to reduce
overall implementation time to the practical minimum. However,
it would also guard against compressing critical actions (such
as the detailed engineering design) into excessively short time
intervals. Second, it would result in quantification of the
actions to be taken in order to comply with requirements by a
given project.
Depending on the size, location and complexity of a pro-
ject, thirty or more major laws and regulations must be complied
with. Without careful planning and documentation, endless de-
lays can be caused by the failure to deal with one or more of
these requirements in a timely manner. In other cases, similar
delays can result from differences of opinion over the adequacy
of consideration given, actions proposed, or measures provided
to meet requirements. Such potentially costly delays could be
avoided by interactive planning and negotiations done well in
advance of design and construction.
Both the requirements and the action plan for dealing with
them would be developed in the implementation schedule. Differ-
ences with responsible agencies could be resolved in advance so
that facility planning and construction could proceed expedi-
tiously. The EPA Region IX program for dealing with archeol-
ogic sites, and the California program (AB-884-Dec 1977) for
dealing with California Environmental Policy Act requirements
and state regulatory approvals exemplify how this approach would
work.
Another important benefit of this approach would be to im-
prove the effectiveness of meeting all applicable requirements.
For example, compliance with fair labor standards and equal em-
ployment opportunity requirements. In each case, the Project
Implementation Plan would call for a specific plan of action to
be developed. Responsibility for these action plans would be
useful to the grantee or to the grantee's agent for project
management. Federal and state responsibility would not be dele-
gated 1 Rather, the federal role would become one of auditing
performance to insure that: (1) planned actions were taken; and
(2) results expected to be achieved by taking the planned ac-
tions were actually achieved by taking those actions.
Summary—The project implementation plan would be an over-
all work plan, schedule and budget for planning, design and im-
plementation of the project. Implicit in the approach is: (1)
definition of each result to be achieved, (2) development of a
specific set of actions to achieve that result, (3) assignment
of responsibility for each action, and (4) establishing the
financial, administrative, audit and control procedures.
42
-------
h«5 t V?? be ?irected to: (1) minimizing the overall
schedule; (2) insuring that adequate time was provided for cri-
tical elements of the process, such as design; and (3) insuring
that adequate resources were devoted to meeting related goals
such as construction inspection, value engineering and equal
opportunity compliance.
Equitable Cost Distribution—
A second part of the recommendation is that costs be dis-
tributed equitably between federal, state and local interests
considering the nature of the requirements and goals of the
project. This recommendation would be implemented by: (1)
identifying separate goals and requirements as previously dis-
cussed; and (2) expanding the facility plan to include an eco-
nomic evaluation/cost allocation section. This section would be
similar to comparable sections in project plans for major fed-
eral water resources projects. The only difference is that
"compliance with requirements" would be treated as "benefits" in
cost allocation calculations. A brief discussion of the process
envisioned follows.
The first step in developing cost allocation would be to
define a base case project. A base case project is one which
would meet all requirements directly related to the national
water pollution control effort at a minimum life-cycle cost.
Water quality related goals include such things as treatment
requirements, discharge requirements, water quality standards,
inflow-infiltration requirements, etc.
The second step would be to formulate the economic alter-
native project. This would be defined as the project which met
all applicable requirements at the minimum life cycle cost. Any
incremental costs (over and above the base case project cost)
would be allocated among non-water pollution control purposes.
This allocation of incremental costs between federal, state and
local interests would be on the basis of standard economic pro-
cedures for cost allocation.
To implement the proposed recommendation, federal pollution
control requirements would be considered first in the cost allo-
cation procedure. The federal cost share for the project would
be based on: (1) the standard formula in the enabling laws ap-
plied to base case costs (e.g., 75 percent of the base case
cost); plus (2) 100 percent of the cost allocated to meeting
other federally imposed requirements, as determined from the
cost allocation calculations.
The basic purpose of this part of the recommendation is to
identify and define the federal requirements and responsibili-
ties as the first step toward implementing the overall recommen-
dation. The formulation is based on two assumptions: (1) that
federally imposed mandates are for the widespread general public
43
-------
benefit; and (2) that standard procedures developed for other
similar federal water programs should be applied (rather than
developing new and unique formulas and procedures).
Another benefit would be derived from this part of the re-
commendation. A record of the cost of compliance with various
federal, state and local mandates which are not related directly
to water quality would be developed. The approach would also
insure that waste water dischargers do not pay (through user
charges) for cost of meeting unrelated goals.
Cost saving and expediting benefits would also result from
the cross-walking of legal, administrative and financial re-
sponsibility. Often delays are incurred, and resentment gener-
ated, because requirements are imposed on the grantee without a
clear definition of: (1) what is required; and (2) how imple-
mentation of the requirement is to be financed. Cooperation,
understanding and more rapid progress toward attainment of all
goals will be achieved by addressing this problem directly.
A third part of the recommendation is to preserve maximum
flexibility for planning of projects to meet local needs. The
basic purpose of this recommendation is to permit formulation of
multi-purpose projects which also address important local pri-
orities. This will insure the grantee's active interest in pro-
moting the project, and working diligently to negotiate solu-
tions to any problems that may arise. For example, suppose a
community with high unemployment is being mandated to divert
scarce local funds into water pollution control. It might be
possible to formulate a labor intensive water pollution control
project alternative which met all applicable requirements. In
this case, by paying the incremental cost of the labor intensive
alternative (compared to the most economic alternative), the
community could address its own priority needs while accomplish-
ing the mandatory pollution control objective.
Under existing (August 1978) EPA policy, this option might
not be open to the community. The reason is that only the capi-
tal construction portion of the project is eligible for grant
funding. Thus, if the labor intensive alternative had a lower
capital cost than the economic alternative, the federal grant
would be reduced.
Implementation—Existing grant policy would need to be
changed to implement this recommendation. The federal policy
should be to pay the legal share of the economic alternative, as
previously recommended. This should be the case even though
some other alternative is actually constructed. The local cost
share would be: (1) the cost of the economic alternative re-
duced by federal and (where applicable) by state grant contri-
butions; plus (2) the incremental cost of the proposed alterna-
tive over and above the cost of the economic alternative. This
44
-------
formula should prevail even where the grantee seeks assistance
from another federal source to defray the incremental cost of
meeting secondary objective(s). Compliance with federal non-
water quality goals imposed by law or regulation should (if the
recommendation is accepted) be federally funded because compli-
ance with these is a necessary part of project implementation.
From the program overview perspective, maximum value is derived
by building the most economic alternative works possible (con-
sidering the established priority ordering) as soon as possible.
Where a project meets the goals of another funded federal
program, existing policy calls for sharing of all costs accord-
ing to a benefits allocation procedure. The consolidated grant
procedure is time-consuming. Rarely will the second federal
program give the second project objective a high priority for
funding. However, it is often possible to increase the priority
for federal funding of the incremental cost of the secondary
project purpose. This is because the effectiveness of the dol-
lar expenditure can be increased dramatically when the second
program only pays the incremental cost of the multi-purpose pro-
ject. Thus, by treating fundable federal goals in the same man-
ner as federal goals imposed by rule or regulations, multi-
purpose projects would be greatly facilitated. To avoid any
potential abuse of this recommended policy, it should apply only
where the secondary purpose is incidental to the wastewater
treatment purpose. This could be controlled by placing a ceil-
ing on the economic alternative-recommended alternative differ-
ential. The recommended ceiling is 25 percent of the cost ef-
fective alternative cost. It would also be necessary to place
a time delay limitation on this alternative. Two criteria are
recommended: (1) the schedule for attainment of water quality
goals should not be extended by more than 10 percent (as com-
pared to the possible schedule for the economic alternative) ;
and (2) the overall project could not be extended by more than
one year or 25 percent (whichever is higher) beyond the economic
alternative compliance date.
To implement this part of the recommendation, any secondary
project purposes and their scheduling impacts would be discussed
in the project implementation plan. The economic evaluation,
cost allocation and detailed schedules would be presented in the
amended facility plan.
Evaluate Innovative Technology in Facility Plan
To assure cost savings and environmental benefits of inno-
vative and alternative technology is considered thoroughly, it
is recommended that:
As soon as possible after the decision is made to consider
grant funding for a proposed wastewater treatment project, an
evaluation should be made to determine the appropriateness of
45
-------
including innovative technology in the project. Where innova-
tive technology would appear to warrant further consideration, a
detailed action plan should be developed for inclusion in the
facility plan. As a minimum, the innovative technology plan
should: (1) identify the innovative technology appropriate for
inclusion in the project; (2) include an economic evaluation of
the potential impact of the proposed innovative technology on
the proposed project; (3) include a general evaluation of the
impact of such an innovation on the national wastewater program;
(4) include an assessment of the risk of failure of the innova-
tive technology; (5) describe actions to be taken in the event
of failure of the innovation; and (6) describe the criteria and
procedures that will be used to evaluate the technical and eco-
nomic performance of the innovative technology (including an ex-
plicit description of circumstances constituting failure of the
technology which would initiate the failure response).
Amendments to P.L. 92-500 passed in December 1977 require
grant recipients to analyze innovative and alternative treatment
processes and techniques for use in wastewater treatment works.
Provision is made for a 10 percent increase in federal grants to
provide for 85 percent of related construction costs. Regula-
tions for implementing these new provisions are currently (March
1978) being reviewed; such matters as the criteria for distin-
guishing between conventional and innovative technology are
presently undelineated.
Independently, this project identified the use of innova-
tive technology as having considerable potential benefit in the
form of reducing construction cost and/or improving reliability
and/or performance of waste treatment works. However, by virtue
of the legal implications of performance failure, there is a
strong bias toward conventional technology and proven perform-
ance criteria. The new law, if implemented in accordance with
congressional intent, will do much to stimulate implementation
of new cost saving technology.
The definition of innovative technology should be broad,
including any facility or procedure that will: (1) reduce the
cost of treatment while meeting accepted treatment criteria; (2)
improve the performance of conventional treatment techniques;
(3) improve the reliability of treatment; (4) reduce energy de-
mands associated with treatment of wastewater; or (5) reduce
other adverse environmental impacts (such as air pollution) as-
sociated with treatment of wastewater.
Innovative technology should be carefully evaluated to as-
sure that benefits to the project outweigh the risk of failure
of the innovation. In addition to a careful engineering analy-
sis, it may be desirable to develop pilot processes to provide
design and performance data.
46
-------
Projects incorporating innovative technology with any sig-
nificant risk of failure should also incorporate fall-back pro-
visions to implement in the event of failure. For example, the
plant layout should include space for conventional technology,
and the hydraulic profile should accommodate conversion to con-
ventional technology without major design changes, etc.
Finally, every project incorporating innovative technology
should also address evaluation, correction in the event of fail-
ure, and technology transfer of either success or failure. To
accomplish this the technology transfer action plan should de-
fine the performance objectives of the proposed innovation.
Both technical and economic objectives should be addressed. A
minimum for acceptable performance should also be defined in
advance. If evaluation demonstrates that minimum performance
criteria are not met, fall back to the conventional technology
would occur automatically. To implement this process a perform-
ance evaluation program would be described in the innovative
technology action plan. Upon completion of construction, the
performance evaluation plan would go into effect.
At the conclusion of the performance evaluation period (a
maximum time of 2 years is recommended) a determination of the
innovative technology would be made. If performance failed to
meet the predetermined minimum criteria, action would automati-
cally be initiated to implement the failure response plan. An
exception would be allowed in cases where a more limited modi-
fication could be demonstrated to be appropriate (e.g., where
experience derived from the evaluation demonstrated that a minor
modification to the innovative facility would correct perform-
ance deficiencies).
Summary--Innovative technology recommendations are:
1. Prepare a plan describing the innovation.
2. Make an evaluation demonstrating that the technical
and economic benefits outweigh any risk, and that the
level of risk of failure is acceptable.
3. Prepare a plan of action to implement in the event of
failure.
4. Facilitate adoption of evaluation criteria and an
evaluation program.
All of these features should be outlined at the earliest pos-
sible stage of a project. The description and the economic and
risk evaluation should be contained in the Step 1 facility plan
report. The failure response plan and the performance evalua-
tion program should be completed prior to acceptance of the
Step 2 plan and report. Implementation of the performance
47
-------
evaluation program could be treated as an extension of the Step
3 grant (in a fashion similar to plant startup), or alternative-
ly as a fourth step in the grant program. Similarly, any re-
placement could proceed as a Step 3 grant amendment, or it could
become a fifth step in the grant process.
As a final note, implementing the technology transfer sug-
gestion would only require the inclusion of appropriate elements
in the evaluation program.
Design Parameter Development
Treatment plant design is frequently based on standardized
design criteria, such as the 10 State Standards, or on data from
brief surveys and pilot plant studies. The high cost of con-
struction resulting from this approach is described in Section
3. In contrast, accurate process design data for treatment
plant expansion and upgrading can best be developed from ex-
tended evaluation of conditions at the existing facility. The
relative cost of long-term studies undertaken by treatment plant
staff would be minimal since most needed operational data are
normally available. Therefore, it is recommended that:
"In order to determine optimum design parameters EPA
should sponsor evaluation at treatment plants approach-
ing design capacity for one or two years prior to com-
mencement of facility planning."
The recommended evaluations would be facilitated by making
several related procedural changes. First, EPA should provide
funding for construction of minor modifications to existing
facilities so that full-scale multi-stream process evaluations
can be undertaken. Second, both EPA and state agencies should
permit waiver or reduction of routine sampling requirements
during evaluation periods of one to two years in order to free
existing laboratory facilities and staff to monitor experimental
work. Third, occasional violations of NPDES permit limitations
will occur and these should be accepted by regulatory agencies.
And fourth, funding for additional analysis and .development of
design criteria should be allowed as part of the Step 1 grant.
It is not realistic to expect that this approach would be
initially applied to every wastewater treatment plant in antici-
pation of a potential future expansion. Many smaller plants do
not have the technical capabilities to handle such a program.
Therefore, a pilot program is suggested. A sample of 10 plants
having high priority for funding of plant expansion should be
selected. These plants would be subjected to intensive studies
to develop design criteria. An evaluation would then be made to
determine how much the design engineer was able to save as a
result of the availability of reliable design criteria. Based
on the results of this pilot study decisions would then be made
48
-------
regarding fuller implementation of this recommendation. The
data produced from plants of, say, 5 mgd and above can be ap-
plied to smaller facilities provided a careful comparison of
sewage characteristics is made.
Design/Construction Periods
Both optimum and minimum time intervals exist for each
activity associated with a wastewater treatment project. At-
tempting to accomplish activities in an interval shorter than
the optimum will increase costs, sometimes rather abruptly.
This is especially true of design and construction (and of com-
bined fast track design-construction interval as well).
The increase in construction cost resulting from excessive
schedule compression comes from obvious sources; such as working
overtime, compressed delivery periods, increased risk of errors
resulting in high liquidated damages payments, etc. Higher con-
struction costs, which result from a compressed design period,
are more subtle. Cost increases include: (1) inability to
maximize value engineering; (2) use of conservative, well-tried
designs to minimize conceptual design time; (3) problems associ-
ated with use of large numbers of staff, some of whom may be
trained or temporary; (4) higher change order amounts; etc.
Certainly the use of, and the potential savings from unconven-
tional and novel methods is precluded.
These factors can become even more serious in the context
of an "enforcement" setting. Both the engineer and the contrac-
tor can come to see themselves as the "target" of enforcement if
the orders do not permit them to accomplish their respective
roles well.
In the past, both EPA and other regulatory agencies have
recognized the need for reasonable design and construction
periods when setting deadlines for compliance. Unfortunately,
delays in other elements of the schedule have almost inevitably
occurred. The net result always seems to be a compression of
time allowed for design and construction. To deal with this
problem it is recommended that:
Regulatory orders, issued pursuant to the Federal Water
Pollution Control Act as amended, specify and follow
the development of a project implementation plan incor-
porating the minimum practical overall schedule. The
steps required to comply with applicable requirements
along with both the interim and final time tables
would, by appropriate reference, become the implement-
ing schedule for the order.
49
-------
Consider Fast Track Construction Management Early in Project
Development
In many cases, consolidation of the design and construction
interval can achieve considerable savings in construction cost.
A cost saving realized by more rapidly implementing the Step 3
construction phase is largely due to avoidance of inflation.
Although it can be argued that the cost of deferring construc-
tion is not a true savings since future costs are paid with in-
flated dollars, the savings to the EPA grant program is more
tangible. This is because appropriations are fixed for the next
5 years with the $20 billion budget authorized by Congress.
Therefore, if inflation effects can be minimized by minimizing
avoidable delays in the design-construction sequence (or at any
other point in the process) then more pollution control facili-
ties can be built with the fixed EPA budget. Fast track con-
struction approaches are one way to save some time during the
lengthy Step 2-Step 3 sequence.
Cost Reduction Recommendation—
To reduce cost through minimization of time taken in the
conventional project design and construction sequence it is
recommended that:
As soon as possible after the decision is made to
consider grant funding for a proposed wastewater
treatment project, an evaluation should be made to
determine the appropriateness of utilizing fast-
track design/construction techniques. Where a
design-construction approach would appear to be
appropriate, a detailed fast track action plan
should be developed for inclusion in the facility
plan.
A model for this has been developed in California. A
Guideline published by the California State Water Resources
Control Board entitled "Managing Construction" is suggested for
study if this recommendation is to be given more detailed con-
sideration. The California approach requires the grantee to
formulate a Management Plan for construction during the facility
planning phase, and to submit a plan for approval during Step 2
at approximately the 10 percent design review. The plan must
specify:
1. Construction Contracting - number and type of con-
struction contracts to be used.
2. Services During Construction - required services and
who will perform them.
3 . Grantee Organization and Personnel - responsibility,
lines of authority, staffing levels, and personnel
qualifications.
50
-------
4. Financial Planning - expenditures, revenue sources,
and cash flow requirements.
5. Grant Sequences - strategy for timing and sequence
of grants.
6. Management Procedures and Techniques - scheduling,
cost control and value engineering, and reporting
systems.
7. Master Schedule - major activities in design and
construction.
During the implementation phase of Preconstruction the
grantee takes the necessary actions before Step 3 to achieve
the desired results in construction. These include:
1. Contracting for Construction Services - public an-
nouncement, evaluation of respondents' qualifica-
tions, solicitation and evaluation of proposals,
negotiation of scope of services and engineering
fees, and award of subagreement.
2 . Value Engineering Program - recommended involvement
by an independent organization, and required in
projects with an estimated construction cost of
$10 million or more.
3 . Conditions of the Contract - listing of mandatory
and recommended contract conditions for Clean Water
Grant projects.
4 . Prebid Estimates - submitted with final plan and
specifications; estimates must be broken into pro-
cess segments or systems.
The California approach also calls for: (1) accelerated
procurement activities including purchase of some items prior to
completion of design; (2) development of specifications, and
schedule preapproval of equipment prior to bidding; (3) sched-
uling bid opening dates, conferences, and addenda procedures;
and (4) development of evaluation criteria for proposals.
Construction phases are planned through to the final audit.
During the planning phase construction management and communica-
tions systems are established, including detailed construction
scheduling and scheduling of value for progress payments. Com-
munications procedures for processing submittals, monitoring
equal employment opportunity and labor compliance are required
to be maintained by the grantee. Procedures to be followed
during inspection and testing, and for documentation and changes
during construction are also discussed and described.
51
-------
The evaluation of fast track procedures, which takes place
during facility planning, should compare time required for the
more conventional design-construction sequence with that re-
quired for a fast track alternative. A base case schedule would
be defined following the conventional approach for the recom-
mended facilities. Fast track should be implemented where it
allows significant overall cost savings expected, or where over-
lapping schedules are required to provide time needed for de-
sign.
It should be noted that the California model is compatible
with the overall approach recommended at the outset of this
chapter. The only difference is that more attention would be
given to specific requirements considered to be important (such
as the innovative technology considerations).
Consider consolidated Step 1-Step 2 Project Plan early in
Project Development.
Small Projects—
Amendments to the Federal Water Pollution Control Act
passed in December 1977 permit the consolidation of Steps 1 and
2 for small facilities. It is expected that this will reduce
both the time and the engineering costs associated with small
projects. Many of the requirements pertaining to large projects
are inappropriate to these smaller projects.
To accelerate small projects, it is recommended that:
EPA review the construction grant regulations, and
develop streamlined regulations for consolidated Step
2/3 projects.
Every effort should be made to streamline, simplify and
eliminate requirements which are not relevant to small projects.
This greatly accelerates the construction of small systems, and
it should greatly reduce the costs as well. Implementation
should proceed in two phases. Phase 1 would involve elimination
of all identified requirements which are not required by law.
Phase 2 would involve requesting legal authority to eliminate
other non-essential requirements for small systems.
Design and Construction Workload Leveling
To eliminate wasteful expenditure caused by the fluctuating
design, estimation/bid and construction requirements of the
present EPA grant funding program, it is recommended that:
"A firm governmental funding and project authorization
be adopted over a five-year moving period, in place of
the present annual budget appropriation procedure."
52
-------
The wasteful expenditure caused by present annual determi-
nations of workload is developed earlier in this report. This
recommendation calls for a reversal of the present system, in
which state and EPA funding determinations are made, and engi-
neers and contractors are expected to staff for high workloads
for periods as low as 6 months. It is recommended that long-
term projections be made for funding so that engineers and con-
tractors are able to increase or decrease staffing in proportion
to demand. The training period for a design engineer is esti-
mated as 3 to 5 years, and for a project engineer 8 to 10 years.
These figures are similar for contractor's management staff.
Training of design and construction personnel is a function of
experience gained; shorter periods are not considered to be
feasible.
It is appreciated that the major funding decisions are made
by elected representatives rather than the permanent technical
staff of EPA. However, if EPA can show that long-term funding
will enable overall cost savings the Congress may be convinced
to budget several years ahead. Certainly a commensurate ap-
proach has been carried out on other large programs (defense or
public work). It is therefore recommended that EPA conduct a
survey to determine the extent of temporary staff employment
caused by fluctuating staffing needs. Furthermore, investiga-
tions should be undertaken to determine what additional degree
of conservatism is built into project designs as a result of un-
reasonably short design periods due to the need for compliance
with regulatory timetables. The effect of compressing design
periods on construction costs can be significant for when
pressed for time an engineer will gravitate to more conservative
choices since risk of process or structural failure have more
serious consequences to him than a cost increase.
Standard Equipment
To eliminate wherever possible the high premiums paid to
obtain non-production line equipment; to simplify later replace-
ment by the municipality; and to eliminate delays arising from
the manufacturer's need to interrupt production line schedules,
it is recommended that:
"EPA encourage design engineers to maximize the use of
standard manufacturer's packages of equipment wherever
process reliability is not compromised."
To maximize the life of equipment used in wastewater treat-
ment plants engineers have developed specifications requiring
various non-standard modifications of equipment, such as elec-
tric motors. In the past, manufacturers of such items had less
sophisticated production lines, and greater competition existed
between manufacturers. At the present time there are fewer
manufacturers with more sophisticated production techniques.
53
-------
Relative costs for non-standard equipment are much higher, and
delivery quotations much longer.
As an example, the following prices are for electrical
motors, averaged between 5 hp and 40 hp, 1,200 rpm units.
Motor Type Relative Cost
Open drip-proof 1.0
Totally enclosed 1.33
Totally enclosed, severe duty
(1.15 service factor) 1.50
Explosion-proof
(1.15 service factor) 1.71
A manufacturer of process equipment will normally provide
the open drip-proof motor as standard. If the severe duty
(often called mill and chemical) motor is required not only is a
premium of 50 percent of first cost paid, but an increase is
also added due to the quantity of motors purchased. The manu-
facturer may purchase standard motors in lots of 50 or 100. Special
motors will be obtained in ones and twos. Obviously, a further
cost must be faced due to the loss of quantity discount.
A further area for wider acceptance of manufacturer's
standards is control equipment. Most complex equipment is norm-
ally supplied with manufacturer's control packages. In many
instances, the design engineer has required additions or altera-
tions to the standard package for various reasons. Such changes
may involve a disproportionate increase in cost of control
equipment, and should be carefully evaluated on a cost basis.
The design engineer should be discouraged from specifying
non-standard equipment, except where process reliability is a
concern or where it otherwise cannot be avoided. No justifica-
tion can be shown for purchase of an ancillary item, such as an
air conditioning feature that will last 15 years instead of 10,
if a substantial cost premium (e.g., 200 percent or more) is in-
volved. It is recognized that certain electrically hazardous
areas require explosion-proof equipment; wherever possible
equipment should not be located in such areas.
Process reliability for many processes is highly dependent
on certain major equipment items (e.g., blowers, pump, engines).
Although standard equipment is available for these duties, the
risk of breakdown should always be considered for key process
equipment; particularly where their repair costs approach
54
-------
original purchase price. Premium costs associated with the use
of heavy bearings and larger shafts can often be justified when
repair costs and environmental implications of more frequent
equipment disruption are evaluated. It is difficult to gener-
alize when differences in wear and climate are of concern; for
example, in Seattle, Washington, the high grit load associated
with the combined sewer system and frequent rains cause as much
wear to pumps in one year as would be found in a typical
Southern California system in five years.
It can be argued that municipalities will benefit from in-
creased use of standard equipment. Regrettably/ a small munici-
pality wishing to purchase a specialized non-standard item must
often wait for extended periods for delivery. This fact inev-
itably reduces the mechanical reliability of wastewater treat-
ment plants with such equipment. In contrast, standard equip-
ment is usually available "off-the-shelf"; if not directly with-
in the municipality itself,at least in the nearest trading
center. Where non-standard equipment is justified based on
process reliability maintenance personnel must pay careful at-
tention to spare parts inventories.
It is recommended that EPA caution designers to be conscious
that excessive use of non-standard equipment leads to cost in-
creases. Accordingly, there should be careful justification by
the design engineer where significant non-standard equipment is
specified.
Adoption of Less Conservative Design Data
It is necessary that municipalities and engineers be ac-
tively encouraged to adopt less conservative design data. Cur-
rently, the trend is to use increasingly conservative design
data. It is therefore recommended that:
"EPA regulations be modified to include provision for
further funding for design and construction beyond
Step 3 subject to certain conditions. These conditions
would be drawn up around requirements that the engineer
and municipality show their intent to use less conser-
vative data during Step 2."
EPA's policy is to achieve maximum economy in wastewater
facility design. Two forces exist opposing this desire. First,
municipalities are aware that funding may not be available in
the future, or that having received one grant, they might not
be eligible for a future grant; their concern being to ensure
that adequate facilities are provided. Secondly, engineers, in
common with all other professions, are coming under increasing
liability pressure. Therefore, their tendency is to design con-
servative plants. In the past this tendency has been accentu-
ated by pressure from municipalities; who obviously do not want
55
-------
to be faced with the need to undertake remedial work, or to con-
struct additional units entirely at their own cost within a few
years of project completion. Recent amendments (P.L. 95-217) to
the Federal Water Pollution Control Act have added special pro-
visions for funding innovative technology which minimize this
risk and actually encourage municipalities to implement less
conservative projects. Funds are also available to correct or
replace failures.
Following the spirit of these amendments, EPA should adopt
procedures encouraging engineers to use optimum rather than con-
servative design data for conventional facility construction as
well. In the event that operational data from the completed
plant indicates the applied design data was insufficient, EPA
should fund an additional project. This project, which may not
be required for five or even ten years, would be of such capac-
ity as is required to meet demonstrated treatment needs. It is
recommended that additional funding, in the form of a supple-
mental or second grant, be provided to cover the cost of this
work.
Implementation of the solution is less obvious than the
solution itself. Several fears exist: first, that the engineer
would avail himself of this subsequent phase as an insurance
against poor design; second, that municipalities would use the
subsequent phase to ensure maximum facilities are provided. The
resolution of these fears would appear possible within the
framework of existing Step 2 procedures.
At the time the pre-design, value engineering report is
reviewed, the proposed design data should be evaluated by the
designer, value engineering team, and state and/or EPA engi-
neers. A decision to proceed with the proposed data, or to use
less conservative figures should be reached. The difference in
capacity between the initially proposed design data and that
finally adopted for Step 3 should form the basis for a future
supplemental contract if proven necessary. Note that the engi-
neer, in adopting less conservative design data should contem-
plate the omission of a complete element; such as a sedimenta-
tion tank or pass of an aeration tank. The design should allow
for easy supplementation of the additional element(s) if needed.
For example, one unit of four in a square layout would be
omitted.
The potential cost savings realizable from this suggestion
are large. The potential of saving one unit in six or eight
constructed exists, giving a fair indication of potential sav-
ings. The familiar argument that if additional facilities are
to be needed within 5 to 10 years they should be added now be-
cause it is cheaper is fallacious. The real value of construc-
ted facilities is not based on any fixed datum. The real cost
of constructing 5 or 10 years hence is likely to be very similar
56
-------
to the cost today. In the meantime the released grant funds can
be used for alternate schemes where some water quality benefits
will be immediately realized.
One final point to note: if the previous section on design
parameter development is adopted, the value of this recommenda-
tion will be greatly diminished for plants over 5 mgd in size.
It will remain valid for plants of lesser size.
Novel Idea Adoption
Recommendations concerning novel idea adoption were pre-
pared prior to passage of P.L. 95-217,which incorporated a pro-
gram for implementing innovative technology,
but are in the same spirit as the 1977 Amendments to the Federal
Water Pollution Control Act. To provide conditions in which
novel cost reducing ideas can be tried and tested to determine
their suitability and cost-effectiveness, it is recommended
that:
"EPA issue regulations encouraging engineers to adopt
novel methods and materials, and indemnify those who
do so. Further, that a group be established to re-
cord and publish the successes and failures of adopted
novel ideas."
Adoption of novel methods and materials of construction is
unlikely due to present regulatory and legal restrictions.
Draft (January 27, 1978) guidelines on innovative technology
have been reviewed, and, where innovation applies to in-place
treatment, very substantial cost or energy savings criteria ap-
ply before special funding can be provided.^ Thus innovative
and alternative technology inducements may not influence major
treatment works construction. In order to encourage the use of
new ideas, which may ultimately lead to markedly reduced con-
struction costs, EPA must ensure that engineers and municipali-
ties are not penalized if such ideas turn out to be failures.
It is therefore recommended that EPA undertake three steps:
1. EPA issue a memorandum to all regions and review
agencies encouraging them to accept novel design
methods and materials of construction. Some in-
ducement for more conventional plant innovations
may be appropriate also.
2. EPA establish a small internal group of engineers
to maintain a record concerning the use of novel
ideas. Alternatively, a consultant or consultants
be retained to develop such information.
57
-------
3. EPA adopt regulations embodying their desire to see
cost reducing ideas adopted even where innovative or
alternative technology grant provisions do not ap-
ply; such regulations should provide indemnity for
engineers and municipalities who undertake to use
such ideas.
The design memorandum's intention, recommended above in 1,
should be straightforward. In addition to encouraging the use
of novel methods, the memorandum should prohibit any review
agency from rejecting a design, method or material purely on
the ground that it is untested.
The review group's design, suggested above in 2, should be
uncomplicated. Their intended purpose is to build on the
foundations of this and similar studies; to provide information
on novel ideas, and on the actual field use of those ideas.
Discouragement of Novel Ideas—
The requirement to make regulatory changes in order to en-
courage the use of novel ideas, as well as the innovative tech-
nology provisions of the 1977 amendments, are essential for
greater cost savings within conventional systems. However, it
is a well felt reality that adoption of novel ideas is dis-
couraged by a number of different factors:
First, with the enforcement of vigorous consultant selec-
tion procedures and fee negotiations initiated by EPA, engineers
are coming under increasing pressure to reduce fees. The
ability to investigate and analyze novel ideas to determine
their suitability is limited to the amount of time (as a func-
tion of the budget) that the engineer is allowed. If design
time, including both lapsed time and total manhour budgets,
must be reduced as a result of regulatory pressures, it is in-
evitable that the necessary reduction will be at the expense of
areas such as novel idea evaluation.
Second, engineers are likely to be liable for the adop-
tion of an idea that does not work; the idea's use was
intended to save the engineer's client's money.
Third, at present neither the engineer nor municipality
is offered any incentive to adopt novel ideas which may or may
not work as well as existing technology; or may not work at all.
The EPA has no means of financing unsuccessful ideas used in the
course of normal or conventional design. Indeed, a municipality
whose engineer adopts an unsuccessful idea may find EPA pressure
applied to them to not only correct the idea at their own ex-
pense, but also that they consider suing their engineer for the
cost of renovation.
58
-------
Obviously, all of the above inhibiting factors must be re-
moved before novel ideas can be considered for adoption with
intrepidation. To effect more widespread cost savings, it is
recommended that EPA provide for the use of novel methods by
adopting the following regulation format:
1. Acknowledge novel ideas exist, and that EPA desires
their implementation throughout all aspects of the
grant program.
2. Acknowledge that novel ideas may be partially or
completely unsuccessful. And recognize added risk
has been taken by all parties (EPA, State, grantee,
and the engineer) such that no penalties are to be
imposed on any one party in the event of partially
or completely unsuccessful novel ideas.
3. Provide for EPA to accept the incorporation of
novel ideas into a design at the initial VE review
point (10 to 15 percent stage of Step 2) . It
should be noted that rapid 7 to 14-day acceptance
by EPA is required; longer delay penalizes the
engineer, and discourages his use of initiative.
4. Provide for EPA to monitor, through a small in-
ternal group or consultant, the implementation
and degree of success of the idea.
5. As indicated in the 1977 amendments, provide EPA
with means and procedures to fund replacement of
any facility constructed as a result of novel
idea implementation.
6. Provide for EPA to compensate a municipality
when an idea is partially successful, but its
continued use involves operations and maintenance
costs in excess of those for the conventional
solution.
7. Provide for either EPA, or their appointed con-
sultant, to ensure national dissemination of the
results of such ideas.
Mechanical Pre-Bid Requirements
To provide the most open arena for competitive bidding on
equipment, such as sludge dewatering devices and sludge incin-
erators, it is recommended that:
"EPA regulations provide for mechanical pre-bid of
specialized equipment costing in excess of $500,000.
59
-------
The mechanical pre-bid should take place at the
earliest possible point in design."
Much thought has been given concerning ways to obtain an
increased degree of openness in specifications. Several possi-
bilities were considered before a practicable approach was
identified. Options which were subsequently rejected included:
1. Performance specifications could be written for all
items with the provision that the design would be
modified as necessary to suit the equipment selected
by the lower bidder. Virtually unlimited engineering
fees would be required. This is not considered to
be feasible.
2. Contracts could be worded so that the contractor
may request a change of design be made. New design
details and specifications must then be prepared
and agreed upon between all parties or legal com-
plications may arise. The legal problems and the
costs to each party for making such changes act
as disincentives.
3. The present value engineering system be expanded
to enable the contractor to take 50 percent of
the savings of cost reducing suggestions. As the
value engineering system has only recently been
introduced, it is too early to make a judgment of
that sort. Therefore, no changes should be made
relative to value engineering at present.
The only practical, implementable approach identified is
the use of a performance specification bid at an early stage
which does not restrict the bidder in any way. For example, in
bidding on an incinerator the engineer would not be permitted to
restrict bidders to multiple hearth, or fluidized bed; all fur-
naces could be bid and would then be evaluated by the engineer.
The following would have to be taken into account:
1. Ability to Reject Low Bidder. With a completely
open performance specification, no restrictions
would be placed on a bidder other than that his
equipment be able to perform a function efficiently
for a period of time. The engineer would be re-
quired by the Municipality to determine whether
or not a bidders' claims were correct (either that
or a bidder would need to warrant his equipment
for a 15 or 20-year period - clearly an impossi-
bility) . The ability to reject a bidder, even
though he be the low bidder, would be necessary
to insure the engineer's professional integrity.
60
-------
2. Delay of Final Contract Bid. The introduction of
an additional step in the design process contri-
butes some delay to the production of final plans
and specifications for the general contract. In-
creased costs due to inflation are likely.
Nevertheless, the attraction of potential cost savings from
bidding major mechanical equipment against an open performance
specification exists. In terms of increased competition it
could be anticipated that 5 to 10 percent of equipment costs
could be saved. The format of such bids must be as open as
possible. Present day attempts to bid mechanical equipment
separately are generally based on fairly detailed pre-concep-
tions on the part of the Engineer.
The bid must occur as soon as possible in the design stage.
Only performance and outline process selection data are re-
quired; further detailing will result in unnecessary restriction
on bidders. In order to obtain maximum cost benefits for the
grant program the mechanical bid must be a firm bid to the
owner. And, if the Engineer recommends acceptance, the owner
must purchase the equipment and provide it to the general con-
tractor .
Design/Construction Periods
Higher construction costs presently occur as a result of
regulatory pressure on both design and construction periods.
Such pressure is often a result of preset regulatory deadlines.
And, therefore, can be alleviated if minimum construction cost
is desired. It is recommended that:
"EPA develop and implement a table of optimum design
and construction periods, and provide for their in-
corporation into regulatory agency minimum deadline
requirements, where applicable."
Implementation of the proposed method of tabulating optimum
design and construction periods is recommended as a solution to
the insensitivity of regulatory agencies to higher costs result-
ing from compressed design and construction periods.
Higher construction costs result from obvious sources; such
as overtime labor charges, compressed delivery periods, risk of
high liquidated damages payments, etc. Higher construction
costs from compressed design periods are more subtle. They in-
clude: the inability to schedule for and maximize feedback from
value engineering sessions; the use of conservative, well tried
designs to minimize conceptual design time; conservatism neces-
sitated by the need to employ large numbers of relatively un-
trained temporary staff; higher change order amounts; etc.
61
-------
Certainly the use of, and potential savings from, unconventional
and novel methods is precluded.
Recommendation--
The recommendation is, therefore, to allow optimum design
and construction periods to exist which enable the contractor
and engineer to carry out their work, and produce the most cost
effective end product. It is recommended that either an in-
house EPA team be set up, or an outside consultant be retained
to determine proper design and construction periods. The evalu-
ation should take into account size and complexity of project.
For example, a new $10,000,000 plant can be designed and con-
structed more quickly than a similar plant requiring extensive
reuse of existing facilities. Local climate and other factors
affecting working days should be used to determine design and
construction periods.
On completion of the study, the EPA should issue guidance
memoranda, or some similar means of communication, requiring
agencies to adopt the developed time periods, or show cause why
they are unable to do so (artificial deadlines should not be
just cause). If an agency is unable to satisfy EPA that a real
reason exists for reducing design and/or construction period,
the EPA should assess the additional contract cost which will
result from the shortened period and refuse to fund that ad-
ditional cost.
Interchangeability Provision
In order to ensure that EPA funds only the lowest cost al-
ternative when a municipality determines that its own best
interest lies in accepting a bid from other than the low bidder
for reasons of interchangeability, it is recommended that:
"Paragraph 35-935-2 (b) of the Construction Grant
Regulations be modified to state that the grantee
shall pay the additional costs entailed in purchas-
ing proprietary equipment to provide for necessary
interchangeability of parts and equipment."
Any deviation from the method of selecting the lowest bid-
der from the maximum number of bidders leads inevitably to high-
er cost. An exception to the low bid requirement is provided
for as indicated above. The municipality is concerned with
minimizing future operations and maintenance (O&M) costs. An
identifiable present worth can be developed by comparing the
annual costs of O&M for pump A and pump B when four other pump
A's are already installed. This present worth represents the
maximum differential which should be accepted between the costs
of pumps A and B. Furthermore, this cost represents benefits
only to the municipality, and as such should be borne by them.
The payment of a yearly amount on bonds for the additional
62
-------
capital repayment will still be less than the municipality
would have paid for the additional O&M costs of accepting the
lower bid.
This recommendation requires competitive bidding on the
equipment item. Comparison by the municipality of the differ-
ence between the low bid and the bid of the manufacturer of the
desired equipment with the potential O&M savings will indicate
whether or not rejection of the low bid is economical.
Bid Listing Requirements
To maximize the bargaining power of the general contractor,
thereby obtaining the lowest possible bid, it is recommended
that:
"EPA regulations forbid the listing of equipment
suppliers and subcontractors at the time of bid in
any form. The general contractor shall have the
right of open equipment subcontractor selection up
to the point of initial submittal of working drawings."
The intent of this study is to reveal ways to minimize
construction cost. This end is not realized unless the general
contractor, who is acting in the position of purchasing agent
for the Municipality, is provided with the maximum degree of
negotiating power in his dealings with suppliers and subcontrac-
tors. Objections to this approach have been raised and these
are discussed in later paragraphs. It is emphasized that this
optimum negotiating position is not realized if the contractor
is required to list selected suppliers and subcontractors at the
time of bid. Formal binding agreements are only entered into
following contract award to the general contractor. The con-
tractor must be open to use whatever negotiating tools he deems
necessary in achieving the best possible terms with suppliers
and subcontractors.
Several institutional changes are necessary before imple-
mentation of this recommendation is possible. Many municipali-
ties and some states have requirements that subcontractors and/
or suppliers be listed at the time of bidding; and that the
permission of the municipality or state agency is necessary be-
fore a substitution can be made. EPA has an equal employment
opportunities requirement demanding that a post-bid, pre-award
conference be held to review the affirmative action programs of
contractor and subcontractors. All of these would require modi-
fication to permit the general contractor to make substitutions
as desired.
Objections—
Several objections to this proposal have been voiced, pri-
marily by equipment suppliers and engineers. The major area of
63
-------
dissent centers around a fear that severe pressure by the con-
tractor to bring prices down to a minimum would inevitably lead
to cheapening of the product and a deterioration in the services
that a manufacturer and supplier provide to the municipality.
In practice this is inevitably true. In theory it is supposed
that the engineer in preparing the contract documents can fore-
see and cover all aspects of materials, construction, control,
submittal requirements, start-up, and operations and maintenance
information. However, in practice this is not possible.
A second objection comes from engineers. In specifying two
or three manufacturers who the engineer knows to be acceptable,
preparation of lengthy specifications can be minimized, and the
municipality will be assured of obtaining a product of the de-
sired quality. The requirement that the engineer completely
detail the specification of an item of equipment undoubtedly
means additional cost to the engineer. This fact should be
borne in mind in effecting this recommendation.
Precise cost savings under all circumstances are difficult
to estimate. Cited examples, however, include up to 100 percent
over minimum cost if only one bidder is involved, and 20 percent
over minimum cost if two or three bidders are involved.
Inspector Certification
To provide a predictable and consistent level of construc-
tion inspection on construction projects, it is recommended
that:
"A construction inspector certification system be
introduced; either by EPA, or by the construction
industry at large."
The recommendation for construction inspector certification
arises from indications given by contractors that construction
inspection requirements vary considerably. It is not antici-
pated that an inspection certification system alone will equal-
ize inspection on all projects. Contracting agency requirements
vary widely. A certification system is an essential first step
toward standardization of inspection requirements.
A more uniform competency level among inspectors would re-
move some unknown factors from the contractors' bidding. Where
risk is minimized cost savings would follow.
Suggested Form—
Each state operate a certification system based on national
standards using management funds supplied from the P.L. 95-217
grant program. Each inspection division is to have unclassified
trainees and five grades of qualified inspectors. The inspec-
tion division required for EPA funded contracts are:
64
-------
1. Civil (pipelines, earthwork, paving, general duties)
2. Structural
3. Mechanical
4. Architectural
5. Electrical
6. Instrumentation
A provision enabling experienced craftsmen to become certi-
fied inspectors could be incorporated into the code. Inspectors
presently skilled in wastewater collection and treatment pro-
jects should receive automatic certification commensurate with
their documented experience within each division.
It is anticipated that multi-certified inspectors will be
the major need for inspection staff for small and medium sized
construction projects, where only one or two inspectors are
normally expected to cover day-to-day inspection of all divi-
sions.
A suggested experience requirement list is as follows:
Minimum Field Minimum Field
Total Experience Experience
Field Since Last as
Experience Classification Craftsman
Classification (years) (years) (years)
Unclassified 1-2
23 25
35 25
48 3 -
5 10 2 -
It is recommended that Grades 4 and 5 not be open to auto-
matic entry by craftsmen without examination. Class 4 and 5
inspectors should be required to pass an examination in the
legal and procedural aspects of construction. Class 4 and 5
inspectors would fulfill many of the duties of a resident engi-
neer, on small (Class 4) and medium (Class 5) contracts.
It is further recommended that EPA specify the inspection
requirements for all construction contracts. For example, a 2-
mgd secondary wastewater treatment plant with no special com-
plexity might be defined as requiring either a resident engi-
neer, a Class 3 inspector and an unclassified inspector, or a
65
-------
Class 5 and two Class 2 inspectors. EPA would then provide
construction inspection funding, providing that the minimum re-
quirements are met.
The cost savings that such a program would effect are un-
definable since the costs of the present system are illdefined.
Contractors interviewed identified poor and indecisive inspec-
tion as an item which cost them money, but which they were un-
able to allow for in their bids; doing so ruined their competi-
tive position. Several contractors indicated that they will not
bid for some work because they know the inspection staff of the
contracting agency will cost them an amount that they are unable
to define.
Working Days
To eliminate the weather element risk from contractor's
bids, it is recommended that:
"EPA regulations require all construction periods be
bid in working days not calendar days."
This method of specifying contract period is in use in some
cities. It provides a fair method of reducing the cost of in-
surance against delays arising from foul weather. The adjudica-
tion as to whether any day is a working day, one-half working
day or not should be made by someone other than the contractor
or field inspection staff. The director of public works is an
obvious choice. Whoever is selected should not be so far re-
moved from the site as to experience materially different
weather conditions.
No regulatory changes are required. A minor change to
fixed term inspection contracts is necessary to provide for
possible additional fees (inspection staff are salaried and must
be employed during inclement weather). Such additional fees
should be tied to the number of days designated as non-working.
Change Order Evaluation
To ensure that the consultant's ability to produce complete
and accurate contract documents, which require the minimum num-
ber of site changes, is evaluated during the consultant selec-
tion process, it is recommended that:
"Municipalities be encouraged to inquire into the
change order history of a consultant's prior con-
struction contracts."
The intention of this recommendation is to make consultants
more aware that many construction changes resulting from poor
designs will penalize them when they are evaluated for future
66
-------
projects. As indicated in Section 3, change orders may amount
to a significant percent of contract costs. Care should be
exercised in evaluating change order history, however; some
site changes are beyond the engineer's control.
In evaluating change order amounts municipalities should
consider three groupings. The first grouping are those result-
ing from extra work requested by the municipality, and should
not be held against the engineer. The second group are the un-
known contingency items which arise on any project. Some items
may be borderline between those that the engineer could not
reasonably have foreseen, and those that the engineer should
have foreseen. The third group, which should be considered by
evaluating municipalities, are those items which should have
been foreseen by the engineer.
The last category should either have been avoided, or in-
cluded competitively in the original contract bid. They in-
evitably result in higher project costs.
CONCLUSIONS
The preceeding conclusions were suggested in considerations
taken up in Section 3. They are listed in approximate chrono-
logical sequence, and no attempt to identify relative importance
has been made. The only test for their inclusion was that they
meet the construction cost reduction goal.
Other concerns must be evaluated for a realistic ordering
of ideas. Even if an idea offers great potential for cost sav-
ings, it is of little value if its implementation will not be
permitted on political, social or engineering grounds. Table 8
shows the relative ranking of 16 ideas based on the assessed
and combined potential of cost savings and implementation. Both
potentials are assessed on a 1 = highest to 5 = lowest ranking.
The combined ranking is therefore 1 to 10.
Four of the five best cost reducing ideas occupy the top
four final positions. The fifth idea, elimination of all fed-
eral and state grant funding, has such political shortcomings
that its potential for application is lowest. It ranks eleventh
overall. The two ideas which are easily implemented rank fifth
and ninth overall.
67
-------
TABLE 8. RANKING OF PROPOSED NON-STRUCTURAL SOLUTIONS
Text
Posi-
tion
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Proposed
non- structural
solution
Expansion of the planning
phase
Evaluate innovative tech-
nology in facility plan
Design parameter
development
Design/construction
periods
Consider fast track con-
struction management
early in project
development
Design and construction
workload leveling
Standard equipment
Adoption of less con-
servative design data
Novel idea adoption
Mechanical pre-bid
Design/construction
periods
Inter changeability
provision
Bid listing requirements
Inspector certification
Working days
Change order evaluation
Potential
for imple-
mentation
1
1
2
3
2
3
1
2
2
2
2
3
2
5
1
2
Potential
for cost
savings
2
2
1
3
1
2
4
1
1
5
3
5
3
4
5
5
Total
rating
(1-10)
3
3
3
6
3
5
5
3
3
7
5
8
5
9
6
7
Final
importance
rating
1
1
1
12
1
10
7
1
1
13
8
15
8
16
11
13
Partly
imple-
mented by
PL 95-217
~
_
Ranking Key: 1 = highest
5 = lowest
68
-------
REFERENCES
7. Division of Water Quality, California State Water Resources
Control Board. "Managing Construction of Clean Water Grant
Projects" ,November, 1977.
8. The January 27, 1978,Draft guidelines on Innovative and
Alternative Technology (Appendix) states that in-plant
treatment systems not tied to innovative or alternative
technology definition would have to show that life cycle
costs and net energy requirements were 35 percent and
75 percent or less (respectively) than those of the most
cost effective alternative.
69
-------
SECTION 5
COST CENTERS
METHODOLOGY
The remaining sections of this report deal with structural
factors which affect the cost of wastewater facility construc-
tion. As construction activities encompass a diversity of oper-
ations and materials it is useful to identify elements which can
be evaluated separately in terms of costs. Such elements which
make up a typical construction project can be termed "cost
centers". Cost centers were identified for typical wastewater
collection systems and waste treatment facilities; this cost
center identification process helps to focus attention on high
cost centers where employment of unconventional or novel ma-
terials or methods of construction may prove most feasible.
The nature of the cost centers for collection system and
wastewater treatment plant differs widely. Therefore, different
approaches were required to presently identify those elements
in each type of project.
Collection systems consist almost entirely of pipeline con-
struction. Factors which affect the costs of pipeline construc-
tion can be categorized into a very few major divisions. These
costs are primarily affected by site related conditions, e.g.,
soil types, groundwater levels, utilities, topographic fea-
tures, causes, traffic conditions, etc. In contrast, wastewater
treatment plants include a larger number and greater variety of
cost centers. Since construction of wastewater pumping stations
involves many of the construction elements required for treat-
ment plants, many of the procedures and results obtained for the
treatment plants may be applied to these installations.
COLLECTION SYSTEMS
The cost of storm and wastewater collection systems is
derived from the summed cost of six major construction elements.
These construction elements, which are fundamental for all pipe-
line construction, are:
• Excavation
70
-------
• Trench support
• Dewatering
• Pipe and appurtenances (including manholes)
• Bedding and backfill
• Restoration
As a general rule, the high risk costs associated with
pipeline construction are all related to excavation of the
trench to a suitable level. Once excavation is
completed, the remaining operations are predictable
and sensitive to inspection. Thus the range of unit costs for
sewers reflects variations necessary to accomplish the required
excavation, trench support and dewatering.
Cost Research
Data for this report were compiled through several sources:
Bid tabulations of construction contract awards, quotes from
suppliers of pipe and backfill materials, installation rates,
interviews with contractors, and construction engineering ex-
perience. With the exception of pipe and backfill, very limited
data exists to indicate the relative costs of the six elements
of pipeline construction. Virtually all sewer cost data are
based on the overall in-place cost of the pipe for a given pipe
diameter. Where extra cost items are required for bad ground
or for rock excavation, for example, the higher cost is included
directly in the in-place cost of the pipeline. The bidder is
required to assess varying surface, soil and groundwater con-
ditions, depths of excavation, and determine an average value
for each diameter and include this value as his bid item. The
usual exception to the overall in-place cost is the small per-
centage of contracts where pipe bedding and/or backfill are in-
cluded as separate bid items.
Pipeline contractors were contacted and interviewed to
determine the general approach to the preparation of project
cost estimates. They confirmed that after evaluating the cost
of known elements such as structures, pipe, granular bedding
material, removal and disposal of surplus material, etc., the
uncertain costs are evaluated largely on the basis of experi-
ence. All existing soil survey data are reviewed, the location
of the work is inspected once or several times, similar work is
visited and the contractor's specific experience in the area
recalled. The contractor evaluates these factors, takes his
available equipment and manpower into consideration and prepares
a bid value incorporating all of these factors. Typically, the
bid value is then adjusted to reflect the contractor's current
workload. If his backlog of work is low, the contractor will
71
-------
likely reduce his anticipated profit level in an effort to ob-
tain the work and keep his current staff and equipment busy.
Conversely, if the contractor has a relatively large backlog of
projects, the bid may include a high profit factor, reflecting
the need to purchase additional equipment and expand his staff.
Cost Development
Each of the six previously defined work items is explained
in more detail below. The variables considered in developing
cost for each item are as follows:
Excavation--
Items included in excavation are clearing and grubbing,
pavement cutting, removal and storage of topsoil and salvageable
landscaping, trench excavation and disposal of waste material.
Trench Support—
This item covers a range of types of support from sloping
trench walls where the cost is related to additional excavation
and backfill, to continuous braced interlocking steel sheet
piling. Included in the sheeting costs are materials and labor
for installation of sheeting and associated support systems and
factors for the higher degree of difficulty associated in oper-
ations such as excavation, pipe installation and backfill com-
paction due to interference of complex support systems. The
average cost for trench support is based on the use of a trav-
eling shield.
Dewatering—
This item ranges from zero effort for dry trench conditions
to the use of complex and costly well-point dewatering systems
employed in high groundwater, high permeability areas. The
range of items considered includes all necessary equipment for
well point systems, the cost of underdrains or other drain
systems laid with the trench and the cost of rudimentary solids
separation from discharge water.
Pipe and Appurtenances—
The cost of a range of pipe materials were considered, in-
cluding PVC, asbestos cement, reinforced concrete and ductile
iron. The cost of handling and joining the different materials
are reflected through use of varying installation rates and its
impact on labor and equipment costs.9 Appurtenances include the
cost of manholes averaged as a unit cost per linear foot of
pipeline. Infrequent appurtenances such as siphons, terminal
cleanouts, overflow structures, etc. were deemed to be a very
minor item in overall sewer cost and were therefore ignored.
In the cost tables, minimum cost construction assumes use
of the least expensive pipe available for the diameter under
72
-------
consideration while the maximum cost construction assumes the
use of the most expensive pipe.
Bedding and Backfill—
The costs for material and labor for bedding by class and
for initial backfill were evaluated. General backfill including
compaction are evaluated for native and imported materials.
Where imported material is considered, a factor to allow for
removal of spoil is included.
The total allowed for minimum conditions assumes imported
bedding, the average conditions figure includes imported initial
backfill, and the maximum cost condition assumes all backfill
imported.
Restoration and Disruption—
Disruption includes costs for site-specific items such as
diversion of vehicular and pedestrian traffic, restricted ac-
cess, detours and temporary stream diversions, sewer encase-
ments, safety precautions, provision of contractor's working
area, and costs associated with the maintenance of utility
services through temporary or permanent relocation.
Restoration costs include both temporary and permanent sur-
face replacement, including seeding, sodding, landscaping and
pavement. Also included are removal of detours and stream di-
versions and restoration of the existing street or stream chan-
nel. The minimum cost figure assumes little disruption. The
average value allows for moderate disruption and for the cost
of highway restoration. The maximum figure includes either an
allowance for major disruption, sewer encasement or the restora-
tion of a poorly founded street which requires major reconstruc-
tion following sewer construction. These costs are not gener-
ally additive and an average was therefore used.
Cost Tables
Cost tables were prepared for two different diameters of
pipe, selected because they generally represent different ma-
terials selection. Two depths were selected for analysis, and
the range of encountered costs plus average costs shown. Re-
sults are tabulated in Tables 9-A (metric units) and 9-B
(English units). Table 10 represents the same data in percent-
age of total cost terms.
The in-place costs of pipelines presented in these tables
compare favorably with those presented in a 1978 EPA publica-
tion.-^ The EPA report was compiled through summarizing of bid
tabulations from the ten EPA regional offices.
73
-------
TABLE 9-A. IN PLACE COST FOR SEWERS IN VARYING GROUND CONDITIONS
(1976 dollars per meter)
Pipe
Diameter
Depth to
Invert
Ground
Conditions
Excavation
Sheeting
Dewatering
Pipe and
Appurt .
Bedding
and
Backfill
Restoration
and
Disruption
TOTAL
305 mm 915 mm
2.7 m
Minimum
9.80
3.30
0.00
38.70
11.50
13.10
76.40
Average
26.20
42.70
3.30
46.30
14.40
19.70
152.60
Maximum
65.60
164.00
65.60
55.80
29.50
45.90
426.40
5.5 m
Minimum
23.00
16.40
0.00
55.40
19.70
13.10
127.60
Average
49.20
62.30
6.60
62.30
22.60
19.70
222.70
Maximum
131.20
459.30
65.60
71.90
57.10
45.90
831.00
2.7 m
Minimum
16.40
3.30
0.00
150.30
22.00
19.70
211.70
Average
37.40
42.70
3.30
165.30
26.90
26.20
301.80
Maximum
141.00
164.00
65.60
258.50
45.30
55.80
730.20
5.5 m
Minimum
39.40
16.40
0.00
179.10
34.40
19.70
289.00
Average
74.50
62.30
6.60
195.20
39.40
26.20
404.20
Maximum
282.10
557.70
65.60
290.40
89.20
55.80
1340.80
-------
TABLE 9-B. IN PLACE COSTS FOR SEWERS IN VARYING GROUND CONDITIONS
(1976 dollars per foot)
Pipe
Diameter
Depth to
Invert
Ground
Conditions
Excavation
Sheeting
Dewatering
Pipe and
Appurt.
Bedding
and
Backfill
Restoration
and
Disruption
TOTAL
12 inch
9 feet
Minimum
3.00
1.00
0.00
11.80
3.50
4.00
23.30
Average
8.00
13.00
1.00
14.10
4.40
6.00
46.50
Maximum
20.00
50.00
20.00
17.00
9.00
14.00
130.00
18 feet
Minimum
7.00
5.00
0.00
16.90
6.00
4.00
38.90
Average
15.00
19.00
2.00
19.00
6.90
6.00
67.90
Maximum
40.00
140.00
20.00
21.90
17.40
14.00
253.30
36 inch
9 feet
Minimum
5.00
1.00
0.00
45.80
6.70
6.00
64.50
Average
11.40
13.00
1.00
50.40
8.20
8.00
92.00
Maximum
43.00
50.00
20.00
78.80
13.80
17.00
222.60
18 feet
Minimum
12.00
5.00
0.00
54.60
10.50
6.00
88.10
Average
22.70
19.00
2.00
59.50
12.00
8.00
123.20
Maximum
86.00
170.00
20.00
88.50
27.20
17.00
408.70
U1
-------
TABLE 10. COST DISTRIBUTION
SEWERS IN VARYING GROUND CONDITIONS*
Pipe
Diameter
Depth to
Invert
Ground
Conditions
1 . Excavation
2. Sheeting
3. Dewatering
4 . Pipe and
Appurt .
5 . Bedding
and
Backfill
6. Restoration
and
Disruption
TOTAL
OF 1-3
TOTAL
OF 4-6
305 mm (12 inch)
2.7 m (9 ft)
Minimum
13
4
0
51
15
17
17
83
Average
17
28
2
30
10
13
47
53
Maximum
15
39
15
13
7
11
69
31
5.5 m (18 ft)
Minimum
18
13
0
43
16
10
31
69
Average
22
28
3
28
10
9
50
47
Maximum
16
55
8
9
7
5
71
21
915 mm (36 inch)
2.7 m (9 ft)
Minimum
8
2
0
71
10
9
10
90
Average
12
14
1
55
9
9
27
73
Maximum
19
23
9
35
6
8
51
49
5.5 m (18 ft)
Minimum
14
5
0
62
12
7
19
81
Average
18
15
2
48
10
7
35
65
Maximum
21
41
5
22
7
4
67
33
Costs are expressed as a percentage of total costs.
-------
Pipeline Cost Centers
Inspection of Tables 9-A, 9-B and 10 leads to several
conclusions. Under normal and minimum cost conditions, pipe
and appurtenances costs represent the major cost of construc-
tion. For average conditions, sheeting costs become a major
cost item. For maximum cost conditions, sheeting becomes
the single, most costly item, with excavation and dewatering
of major importance and pipe and appurtenances remaining im-
portant.
Excavation as a percentage of total cost remains approxi-
mately constant and averages 17 percent of total costs. Costs
for trench support increase dramatically according to the
degree of difficulty of construction. The percent of total
cost for minimum conditions — trench jacks or battered
trench — is a nominal 6 percent average, while for maximum
conditions up to 55 percent of total cost may be allocated
to trench supporting systems. Under average degree of dif-
ficulty conditions, using a travelling shield, approximately
30 percent of total cost for 305 mm (12 inch) diameter pipe
and 15 percent for 915 mm (36 inch) was identified against this
item.
Dewatering is not as high a cost center as had been
anticipated. Only a maximum of 15 percent was identified
against this item, and normal costs are minimal. In our
judgement, the reason the maximum figure is proportionally
low is because once a water problem is acknowledged., a de-
finable amount of equipment can be purchased or rented to
cope with the problem. The cost of this equipment will
not increase substantially above this definable base amount.
Piping and appurtenances exhibit an interesting trend.
Under minimum cost conditions, this item represented some 57
percent of total costs. This percentage falls to 40 percent
for average conditions and to 20 percent for maximum cost
conditions. The reason for the declining percentage is that,
although pipe and appurtenance costs are sensitive to type
of material, trench conditions and size, the rate of increase
is a great deal less than those associated with risk elements
such as excavation and dewatering.
Neither bedding and backfill, with weighted averages of
ten and nine percent respectively, nor restoration and dis-
ruption represent a major impact on total costs. These are
substantial but are not considered major cost centers.
Table 11 shows the cost distribution for the cost centers
examined in the study items for 305 mm (12 inch) and 915 mm
(36 inch) diameter sewers. Inspection shows that pipe and
77
-------
TABLE 11. COST CENTER DISTRIBUTION*
305 mm (12 inch)
Cost center
Excavation
Sheeting
Dewatering
Pipe and
appurtenances
Bedding and
backfill
Restoration and
disruption
Excluding
maximum
cost example
19
25
2
32
11
11
All examples
18
37
6
21
9
9
915 mm (36 inch)
Excluding
maximum
cost example
15
13
1
54
10
7
All examples
17
23
3
42
8
7
Expressed an average of total cost.
appurtenances has the greatest impact on construction cost,
followed by excavation and sheeting costs.
WASTEWATER TREATMENT PLANTS
Analysis of cost centers on a plant-by-plant basis for the
EPA construction grant program would provide a wealth of nearly
meaningless data because of the range of sizes and types of
facilities involved. Thus it was first necessary to examine the
scope of the program, select representative sizes of facilities
which would provide the most direct impact in terms of cost
saving, then identify, for those representative sizes, those
unit processes most commonly employed. These representative
samples were then analyzed for cost center identification. Data
for 157 plants were analyzed and two representative plant sizes
selected for detailed analysis. Results are summarized accord-
ing to common construction shapes and types and compared to
total cost. These cost analyses also provide baseline data for
novel method development cost comparisons.
Data Sources
Basic treatment plant costs were derived from the most up-
to-date national data rather than data available on a regional
or company basis. This approach was adopted to avoid a bias to
the developed cost centers favoring regional requirements or
individual company design approaches.
Two sources of national cost data were adopted The EPA
Areawide Assessment Manual, Appendix H data was used for overall
78
-------
treatment plant costs and for costs of process units not ana-
lyzed in depth. Data from an analysis of Construction Cost
Experience for Wastewater Treatment Plants, EPA 430/9-76-002 was
used to determine the frequency of occurrence of treatment plant
size and process. Typical plant sizes and process streams for
analysis were determined from these data.
Data for detailed cost breakdowns were obtained using ac-
tual information from job cost breakdowns or obtained from
Richardons" Estimating Manual 1977. In some instances, costs of
materials-and equipment were obtained directly from suppliers or
manufacturers.
Selection of Typical Plants
The initial requirement was to determine representative
treatment plant sizes for analysis. Data from the EPA
Construction Cost Experience reference covered 157 treatment
plant projects. Of these, 99 were new facilities and 58 pro-
jects involved modification and upgrading of installations.
Figure 4 presents a distribution of these projects by design
flow. The list of projects was then screened to classify them
by size, cost and type. Thirty-seven of the treatment facili-
ties (24 percent of the projects considered) have a capacity of
11 1/s (0.25 mgd) or less. This group, which represented an
expenditure of $14,000,000, or less than one percent of the
total, was comprised mostly of either package treatment plants
or relatively simple facilities such as oxidation ditches and
lagoons. Since the group has only a small impact on the grant
program, it was not given further consideration in the cost
center analysis.
Fifteen wastewater treatment plants larger than 880 1/s
(20 mgd), or 10 percent of the total represented a cost of
$774,000,000, nearly half of the total expenditure for the
projects examined. This group included both biological and
physical-chemical secondary plants as well as tertiary pro-
cesses. Solids stabilization and disposal processes included
watering and thickening, digestion and incineration. A summary
of these projects by type is presented in Table 12.
Typically, unit processes for large plants are constructed
as a number of modules of smaller units. This statement is true
of nearly all processes and most process elements. The more
complex mechanical items such as incinerators and oxygen genera-
tion plants may be provided singly, but in the largest plants
even these are duplicated for reliability. Thus, analyses of
smaller plants will give similar cost centers to those in larger
plants constructed from smaller modules. A decision was there-
fore made to analyze a moderately sized plant rather than a
large plant.
79
-------
100
50
20
10
5
S"
O 2
LL.
? 1
0
co 0.5
Q
0.2
O.I
.05
.02
.01
*•»»,
•**
•^^
s
\
S
\
\
\
y
\
\
\
\
\
\
y
\
V
\
\
^
\
\
\
\
\
\
\
\
\
)
V
\
\
\
\
V
^
Based on data
in Construction
Cost Experience
for Wastewater
Treatment
Plants. EPA
430/7-76-002.
.01
10
50
90 99 99.99
Percent Larger than Standard Flow
FIGURE 4 TREATMENT PLANT SIZE DISTRIBUTION
80
-------
TABLE 12. WASTEWATER TREATMENT,
PLANTS OVER 888 1/s (20 mgd)
Unit process
No. of plants
Treatment
Activated sludge
Oxygen-activated sludge
Step aeration
Physical/chemical
Solids disposal
Dewatering
Thickening
Anaerobic digestion
Incineration
Heat treatment
(two plants did not report)
10
3
1
1
10
10
7
4
1
Of the plants investigated, 108 or 69 percent lie within
the range of 11-1/2 to 880 1/s (0.25 to 20 mgd). This group
accounted for over half of the total cost of all projects.
Further, if a reasonably large plant within this range is evalu-
ated, identified cost centers will be similar to those for
larger plants. Since two plant sizes, 44 1/s (1 mgd) and 440
1/s (10 mgd), were selected for analysis it was felt these
capacities seemed to nearly represent the extremes of the group.
The 44 1/s plant is judged representative of plants with capaci-
ties -between 11 1/s and 175 1/s (0.25 to 4 mgd) and the 440 1/s
plant is considered typical of plants in the range of 175 1/s
to 880 1/s (4 mgd to 20 mgd).
Selection of unit processes for the typical plants was
based upon an analysis of those typically employed in the re-
spective groups. Table 13 presents a summary of this analysis.
A review of Table 13 reveals that over 70 percent of all
plants used the activated sludge process or a variation thereof.
The activated sludge process was therefore selected for the 440
1/s (10 mgd) plant. The activated sludge process or one of its
variations was employed with similar frequency in plants with
capacities in the 11 1/s to 175 1/s range; however, to analyze
an activated sludge process again would be repetitive. Accord-
ingly, the trickling filter, or biofilter, was selected for
analysis to obtain some diversity in the study results. Solids
stabilization was also to be evaluated. Well over half of the
plants in the 44 1/s (1 mgd) size range used aerobic digestion,
while anaerobic digestion was employed in more than half of the
plants 175 1/s or larger. These unit processes were therefore
selected for the two typical plants studied under this investi-
gation.
81
-------
TABLE 13. TYPICAL UNIT PROCESSES
WASTEWATER TREATMENT PLANTS
Unit processes
Treatment
Activated sludge*
Contact stabilization
Extended activated sludge
Step aeration
Oxygen activated sludge
Roughing filter/activated sludget
Physical/chemical
Standard rate trickling filter
High rate trickling filter
Aerated lagoons
Bio-disc
Oxidation ditch
Secondary process not stated
Total
Solids Disposal
Liquid, thickened, or dewatered sludge
to disposal
Anaerobic digestion
Aerobic digestion
Incineration and/or heat treatment
Other method*
Solids process not stated
Total
11 to 175 1/s
27
12
12
1
-
3
-
1
5
6
1
3
-
71
23
12
22
1
-
13
71
11 to 175 l/s
18
1
3
-
3
4
2
-
2
2
-
-
2
37
4
14
4
9
3*
3
37
* Includes 2 plants rated "primary chemical, activated sludge".
t Includes 1 plant rated "trickling filter (high rate), step aeration".
* Two plants reported with both aerobic and anaerobic digestion.
One plant reported with aerobic and anaerobic digestion and heat treatment.
Unit Sizing for Typical Plants
Areawide Assessment Procedures Manual Appendix H was used
as a source for design data and costs of unit processes. In
general, these design data were followed closely in order to
be consistent with the manual's cost data. An exception was
made in the case of gravity sludge thickeners to reflect an
arrangement where both primary and secondary sludges are routed
via the thickener. In the manual, unit cost data provides only
for secondary sludges; so an adjustment was made to the unit
cost data in this case.
Process schematics, wastewater characteristics and design
assumptions for the typical plants are shown in Figures 5 and 6.
Unit loadings, process unit sizing and additional items included
within the scope of the unit process are indicated in Tables 14
and 15. The process arrays selected represent those most com-
monly employed, as described previously. No implication is in-
tended or inferred that these represent recommended arrangements
82
-------
Process Schematic
. Primory
Preliminary Clorifter
High Rate
Trickling Filter
Secondary
Clarifier
6 ^ Ultimate
Disposal
Land
Thickener Digestion Disposal
Wastewater Characteristics:
BOD , mg/1
COD, mg/1
TSS, mg/1
Total-P, mg/1
NH,-N, mg/1
NO,-N, mg/1
UOD, mg/1
Sludge Audit:
Point No.
1
2
3
4
5
6
Influent
210
400
230
11
20
0
406
Sludge Quantity
Ibs/mg
1,080
450
1,530
1,530
765
765
Effluent
45
90
60
8
18
0
150
Concentration
4
3
4
5
3
20
FIGURE 5. PROCESS SCHEMATIC AND DESIGN ASSUMPTIONS,
44 l/s (I mgd) WASTEWATER TREATMENT PLANT
83
-------
Process Schematic
Primary
yft Preliminary Clarifier
Pumps Treatment
Activated
Sludge
Secondary
Clarifier
Disinfection
Gravity Vacuum
Thickener Digestion Filter
Ultimate
Disposal
Wastewater Characteristics:
BOD,-, mg/1
COD7 mg/1
TSS, mg/1
Total-P, mg/1
NH,-N, mg/1
NO^-N, mg/1
UOD, mg/1
Sludge Audit:
Point No.
1
2
3
4
5
6
Influent
210
400
230
11
20
0
406
Sludge Quantity
kg
4,900
3,700
1,900
8,600
4,300
4,300
Effluent
20
45
20
7
17
0
107
Concentration
4
0.8
2.6
8
5
20
FIGURE 6. PROCESS SCHEMATIC AND DESIGN ASSUMPTIONS,
440 l/s (10 mgd) WASTEWATER TREATMENT PLANT
84
-------
TABLE 14. DESIGN DETAILS AND DATA,
44 I/a (1 mgd) PLANT
Process Step
Influent
pumping
Preliminary
treatment
Primary
sedimenta ti on
~
Trickling
filters
Secondary
sedimentation
Disinfection
Gravity
thickening
Aerobic
digestion
Land application
of sludge
_
Description and
design parameter*
Lift, mechanically
cleaned screens
Gravity grit channels,
Parshall flume
Overflow rate.
Rectangular, number
length
width
Sludge pumping head
High rate, loading.
number
diameter
depth
Recirculation rate 3:1
(pump cost in clarifier)
Overflow rate.
Circular, number
diameter
Contact time.
Rectangular, number
length
width
depth
Solids loading rate.
Rectangular, number
" length
width
Adjustment factor for cost''"
curve = 1.0 x 6 x 1900 =
10 820
1-4 mgd
Detention time,
Rectangular, .length
width
depth
Floating mechanical aerators
Lagoon, storage time
surface dimensions
depth
side slope
Land preparation, monitoring
wells and access roads
Design criteria
Metric
6 m
2
3 m
2
2
2
1
20 days
30 days
English
20 ft
800 gpd/ft2
2
62 ft 6 in
10 ft
10 ft
45 Ib BOD/1000 ft3 /day
2
50 ft
6 ft
800 gpd/ft2
2
30 ft
30 min
2
50 ft
6 ft
4 ft 6 in
10 Ib/ft2/day
1
16 ft
12 ft
20 days
50 ft
25 ft
12 ft
30 days
80 ft x 80 ft
8 ft
3:1
* Data in this table is for cost centers development and is no* necessarily
representative of an actual facility.
t Refer Appendix H, p. H-156, cost curves are for secondary sludge, typical
plant utilizes thickener for both primary and secondary sludges.
85
-------
TABLE 15. DESIGN DETAILS AND DATA,
440 1/S CIO lugd) PLANTS
Process Step
Influent
pumping
Preliminary
treatment
Primary
sedimentation
Activated
sludge
Secondary
sedimentation
Disinfection
Gravity
thickening
Anaerobic
digestion
Vacuum
filtration
Description and
design parameter*
Lift, mechanically
cleaned screens
Gravity grit channels,
Parshall flume
Overflow rate
Circular tanks, number
diameter
depth
Rectangular tanks, number
dimensions
Sludge pumping, head
Detention time
Number of tanks
Length
Width
Depth
Diffused aeration
RAS rate assumed 25-100%
Overflow rate
Number of tanks
Diameter
Contact time, adwf
Number of tanks
Length
Width
Depth
Solids loading rate
Circular, number
diameter
Adjustment factor for
costt curve = 10 x 6/12
19,000 , , r
* 8,200 iii^Hl
Two stage, loading
number
diameter
sidewall depth
Floating cover
Gas utilized for heating
Surface loading rate
Number
Diameter
Length
Assumes 12 hr day, 5 day week
_____ — . 1
Design criteria
Metric
6 m
2
2
3 m
6 hr
3
3
30 min
2
1
15 m
2
English
20 ft
800 gpd/ft2
2
90 ft
8 ft
2
167.5 x 37.5 x 8 ft
10 ft
6 hr
3
250 ft
30 ft
15 ft
600 gpd/ft2
3
85 ft
30 min
2
110 ft
15 ft
8 ft
12 Ib/ft2/day
1
50 ft
0.16 Ib/ft3/day
2
55 ft
28 ft
5 Ib/ft2/hr
1
3
8 ft 6 in
* Data in this table is for cost centers development and is not necessarily
representative of an actual facility.
t Refer Appendix H, p. H-156, cost curves are for secondary sludge typical
plant utilizes thickener for both primary and secondary sludges.
86
-------
or practices. For further details of work included in the pro-
cess steps, the reader is directed to the relevant pages of
Appendix H of the EPA Areawide Assessment Procedures Manual.
In establishing the unit sizes, attention was given to di-
rections within Appendix H, i.e., "Secondary clarifiers" pro-
vides that units of less than 46 m2 (500 sq. ft.) be rectangular
while units of greater size be circular. Wherever feasible,
more than one unit is provided. This is a requirement of actual
plants, to permit maintenance while maintaining plant flows.
Overall Cost of Typical Plants
Table 16 presents an estimate of total costs of the typical
plants on a unit process basis. The data are derived from costs
for typical units, with additional costs for site work, miscel-
laneous structures, interconnecting piping, electrical and
instrumentation. These total costs were used as the basis of
comparison for costs within this study. As shown in the table,
two additional factors must be added to the subtotaled construc-
tion cost figures to provide for contingencies and engineering.
TABLE 16. ESTIMATED CONSTRUCTION COSTS
Influent pumping
Preliminary treatment
Primary sedimentation
Trickling filters
Activated sludge
Secondary sedimentation
Disinfection
Gravity thickening (adjusted)
Aerobic digestion
Anaerobic digestion
Sludge pumping
Land application of digested sludge
Vacuum filter dewatering
Miscellaneous structures
Subtotal
Piping (10%)
Electrical (8%)'
Instrumentation (5%)
Site preparation (5%)
Subtotal
Construction contingencies (15%)
Engineering (15%)
Total, estimated construction cost
Estimated cost*
44 1/s plant
160,000
38,000
105,000
160,000
-
200,000
50,000
36,000
115,000
-
-
25,000
-
70,000
968,000
97,000
77,000
48,000
48,000
1,238,000
186,000
186,000
1,610,000
440 1/s plant
700,000
150,000
420,000
-
1,040,000
800,000
190,000
120,000
-
600,000
37,000
-
470,000
250,000
4,777,000
478,000
382,000
239,000
239,000
6,115,000
917,000
917,000
7,949,000
* Costs per Areawide Procedures Manual Appendix H (ENR 247S, September 1976).
87
-------
These factors have not been applied to individual, costs because,
while they are applied as a percentage (15 percent) to the con-
struction cost subtotal for a given facility, in actual practice
it is not the case. Contingencies are used as an allowance for
unforeseen construction difficulties and engineering costs do
not, in actuality, apply uniformly to a facility on a unit-by-
unit basis. The construction cost of the two plants, allowing
15 percent each for contingencies and engineering, is $1,610,000
and $7,940,000 for the 44 1/s (1 mgd) and 440 1/s (10 mgd)
plants, respectively. The reader is cautioned that the data are
valid only for comparative purposes. There may, and indeed
will, be considerable cost differences between the cost esti-
mates herein and the actual construction costs of facilities.
Cost Center Development
Once the basic cost data for the two representative plans
were developed, cost centers for the unit processes could be
identified and analyzed. The remainder of this chapter de-
scribes the development of individual cost centers for unit
processes, and the summation of costs of individual elements to
determine their impact on overall treatment plant costs. These
latter analyses were carried out for the 440 1/s (10 mgd) plant.
Two process units were analyzed for the 44 1/s (1 mgd) plant.
Unit Process Cost Breakdowns
Tables in this section are for treatment plant units repre-
sentative of the common construction shapes. Details of the
cost breakdowns are given in Appendix A. All processes were
analyzed for the 440 1/s (10 mgd) plant where as only trickling
filters and aerobic digesters were analyzed for the smaller
plant.
The analysis was conducted by selecting representative
examples from actual projects, developing unit quantities, and
pricing the quantities. The cost of each major work item for
each major construction element was developed in terms of dollar
figures. These data are included as Appendix A. It should be
noted that although the unit totals are of the same order as in
Table 16, they inevitably differ to some degree. To avoid the
need to introduce cost indices into these calculations, all
costs in the main text are adjusted to the Appendix H cost base
date of September, 1976, or they are represented as percentages.
The percentage figures in Table 22 are based on a plant subtotal
cost and exclude piping, electrical, instrumentation and site
preparation costs, in accordance with the established format of
Appendix H of the Areawide Procedures Manual.
For five units, selected to be representative of each com-
mon construction shape, the cost data have been translated to
Appendix H totals by multiplying all figures by the ratio of
88
-------
Appendix H cost to calculated cost. These cost data are repre-
sented in Tables 17 through 21. The totals for each construc-
tion element and for each work item are shown as percentages,
with two percentages (structural cost = 100 percent, total cost
= 100 percent) developed. A relevant commentary on the unit
cost centers is included in the form of footnotes to many of the
tables in Appendix H.
The information within Tables 17 through 21 and the 13
tables in Appendix A is presented in condensed form. Neverthe-
less, it is still cumbersome when comparative overall treatment
plant costs are desired. Table 22 for structural costs reduces
the data to a simple 6x6 matrix.
Several facts should be noted regarding the cost tables.
The design of individual treatment units varies widely from pro-
ject to project and from designer to designer. For example, in
Table 21, the cost of the "Y-wall" item for forming effluent
launders in concrete is significant, yet in many installations
effluent launders are inboard steel channels, in which case
"Y-wall" cost would be zero and structural steel costs would be
higher. (Note that the "Y-wall" cost item represents an in-
crease over base vertical wall cost.)
"Other structural" and "Other mechanical" items as shown
on Table 22 include a variety of items. Many of the constituent
items of "Other structural" are shown on the individual unit
cost breakdowns (Tables 17 through 23 and Appendix A). The
"Miscellaneous structural" item on the detail sheets includes
such items as metal and concrete stairways and ladders, paint-
ing and other waterproofing, interior drywalls, gratings and
frames, supports, anchors and other attachments, handrails (a
larger cost item in many instances), and miscellaneous archi-
tectural items such as doors, windows, etc.
In a similar fashion, many of the items included in "Other
mechanical" can be identified on the detail sheets. Generally,
only the main process equipment is included under the heading
"Mechanical equipment". For example, in Table 21, the vacuum
filter, vacuum pump, filtrate receiver, filtrate pump and
sludge cake conveyor are included in the "Mechanical equipment"
item, but feed pumps, chemical mixing and feeding systems,
building ventilation and similar equipment are either identified
separately or included in the "Miscellaneous mechanical" item.
Examples of other items typically included under miscellaneous
mechanical are heating, ventilation and air conditioning equip-
ment, ducting, louvers, cranes, sump pumps, plant air and water
service systems, control gates, weir plates, etc.
89
-------
TABLE 17. CONSTRUCTION AND EQUIPMENT INSTALLATION COST SUMMARY
440 1/s (10 mgd) INFLUENT PUMP STATION
TYPICAL OP DEEP STRUCTURES
Item
Earthwork
Foundation base slab
Ground floor and roof slab
Discharge structure
Vertical walls
Precast architectural face panels
Miscellaneous structural
Variable speed pumps
Other mechanical equipment
Total
Cost - Percent of structural
concrete
- Percent of total
Cost*
Formwork
Material
_
763
2,429
769
10,042
-
-
-
-
14,003
5.3
2.0
Labor
_
6,407
4,999
6,472
30,636
-
-
-
-
48,514
18.2
6.9
Concrete
Material
_
21,022
5,606
21,234
21,153
20,260
13,552
-
-
102,827
38.6
14.7
sLabor
_
1,635
7,008
1,651
16,112
3,576
25,167
-
—
55,149
20.7
7.9
Rebar steel
_
4,859
14,294
4,908
21,611
-
-
-
-
45,672
17.2
6.5
Total
57,157
34,686
34,336
35,034
99,554
23,836
38,719
119,249
257,259
699,830
266,165
100
38
Cost as percent
Structural
_
13.0
12.9
13.2
37.4
9.0
14.5
-
-
100.0
Total
8.2
5.0
4.9
5.0
14.2
3.4
5.5
17.0
36.8
100.0
September, 1976 cost levels.
-------
TABLE 18. CONSTRUCTION AND EQUIPMENT INSTALLATION COST SUMMARY
440 1/s (10 mgd) RECTANGULAR PRIMARY SEDIMENTATION TANKS
TYPICAL OF BURIED RECTANGULAR TANKAGE
Item
Earthwork
Tank floor slabs
Tank solids hoppers
Vertical walls
Tank piers
Ground level cross beams
Ground level flat slabs
Miscellaneous structural
Pumping equipment
Sludge collection equipment
Miscellaneous mechanical
Total
Cost - Percent of structural
concrete
- Percent of total
Cost*
Formwork
Material
.
358
3,018
11,249
283
580
668
245
-
-
-
16,401
8.1
3.9
Labor
_
2,214
8,170
33,222
1,667
2,014
1,455
716
-
-
-
49,458
24.3
11.6
Concrete
Material
_
21,548
2,978
9,920
149
1,464
1,537
1,024
-
-
-
38,620
19.0
9.1
labor
19,817
2,623
16,303
769
3,470
1,223
942
-
-
-
45,147
22.2
10.6
Rebar steel
_
24,292
4,385
15,237
3,976
4,973
884
-
-
-
-
53,747
26.4
12.7
Total
15,678
68,229
21,174
85,931
6,844
12,501
5,767
2,927
23,914
125,222
56,672
424,859
203,373
100
47.9
Cost as percent
Structural
_
33.6
10.4
42.3
3.4
6.1
2.8
1.4
-
-
-
100.0
Total
3.7
16.1
5.0
20.2
1.6
2.9
1.4
.7
5.6
29.5
13.3
100.0
* September, 1976 cost levels.
-------
TABLE 19. CONSTRUCTION AND EQUIPMENT INSTALLATION COST SUMMARY
440 1/s (10 mgd) CIRCULAR SECONDARY CLARIFIERS
TYPICAL OF BURIED CIRCULAR TANKAGE
Item
Earthwork
Total base slab
Vertical wall sections
Y-walls
Tank top beams and ground slabs
Influent and effluent encasement
Sludge collection box
Miscelaneous structural
Tank hydraulic distribution
equipment
Pumping equipment
Other mechanical equipment
Total
Cost - Percent of structural
concrete
- Percent of total
Cost *
Formwork
Material
_
852
13,558
12,115
1,640
1,249
1,651
-
-
-
-
31,065
10.0
3.9
Labor
_
4,239
43,302
20,463
3,581
2,465
4,470
-
-
-
-
78,520
24.8
9.8
Concrete
Material
_
28,688
14,034
4,477
3,782
6,827
1,629
6,626
-
-
-
66,063
20.9
8.3
^Labor
_
31,473
15,835
9,084
4,652
2,588
1,063
1 , 342
-
-
-
66,037
20.9
8.3
Rebar steel
_
29,997
20,756
15,104
2,248
3,425
2,400
-
-
-
-
78,930
23.4
9.2
Total
40,735
95,249
107,485
61,243
15,903
16,554
11,213
7,968
286,322
62,136
95,193
800,100
315,615
100
39.5
Cost as percent
Structure 1
_
30.2
34.1
19.4
5.0
5.2
3.6
2.5
-
-
-
100.0
Total
5.0
11.9
13.4
7.7
2.0
2.1
1.4
1.0
35.8
7.8
11.9
100.0
"September, 1976 cost levels.
-------
TABLE 20. CONSTRUCTION AND EQUIPMENT INSTALLATION COST SUMMARY
440 1/S (10 mgd) TWIN PRIMARY DIGESTERS AND SLUDGE CONTROL BUILDING
TYPICAL OF ABOVEGROUND CIRCULAR TANKAGE
Item
Earthwork
Tank floor slabs
Tank vertical walls
Control building base slab
Control building floors and roof
Control building vertical walls
Architectural - tank and building
Miscellaneous structural
Floating gas holder covers
Heat exchangers
Gas mixing equipment
Sludge circulation equipment
Miscellaneous mechanical
Total
Cost - Percent of structural
concrete
- Percent of total
Cost *
Formwork
Material
_
497
13,029
120
455
4,075
589
-
-
-
-
-
-
18,765
9.4
3.1
Labor
_
3,110
43,459
595
948
11,338
1,716
1,443
-
-
-
-
-
62,609
31.5
10.4
Concrete
Ma teria 1
_
6,987
12,599
2,142
922
5,696
15,100
777
-
-
-
-
-
44,223
22.2
7.4
xLabor
—
1,874
2,688
497
241
8,991
16,771
-
-
-
-
-
-
31,062
15.6
5.2
Rebar steel
_
4,573
24,198
3,060
1,691
6,103
2,647
-
-
-
-
-
-
42,272
21.3
7.1
Total
25,758
17,041
95,973
6,414
4,257
36,203
36,823
2,220
187,859
92,222
46,110
39,279
9,819
599,978
198,931
100
33.2
Cost as percent
Structural
_
8.6
48.3
3.2
2.1
18.2
18.5
1.1
-
-
-
-
-
100.0
Total
4.3
2.8
16.0
1.1
.7
6.0
6.1
.4
31.3
15.4
7.7
6.6
1.6
100.0
U>
*September, 1976 cost levels,
-------
TABLE 21. CONSTRUCTION AND EQUIPMENT INSTALLATION COST SUMMARY
440 1/s (10 mgd) VACUUM FILTRATION FACILITY
TYPICAL OF ABOVEGROUND PRECAST STRUCTURES
Item
Earthwork
Floor and foundation slab
Precast concrete wall panels
Roof deck
Interior drywalls
Equipment mezzanine
Miscellaneous structural
Steel frame of building
Grating
Painting
Cranes
Louvers
Vacuum filter and ancillary
equipment
Pumps and metering equipment
Holding tanks
Miscellaneous
Total
Cost - Percent of structural
concrete
- Percent of total
Cost *
Formwork
Material
_
4,493
-
865
928
336
1,964
-
-
-
-
-
-
-
-
-
8,586
6.4
1.8
Labor
_
12,406
-
1,584
1,855
1,041
6,584
-
-
-
-
-
-
-
-
—
23,443
17.6
5.0
Concrete
Material
_
14,933
40,732
3,843
-
1,041
4,640
-
-
-
-
-
-
-
-
-
65,189
49.0
13.9
Labor
_
3,162
7,188
1,140
-
258
3,261
-
-
-
-
-
-
-
-
—
15,010
11.3
3.2
Rebar steel
_
14,924
.-_
431
-
1,095
4,453
-
-
-
-
-
-
-
-
-
20,903
15.7
4.4
Total
3,919
49,918
47,920
7,863
2,783
3,775
20,902
13,728
5,369
24,959
9,360
4,991
227,126
13,728
18,719
14,975
470,005
133,131
100
28.3
Cost as percent
Structural
_
37.5
36.0
5.9
2.1
2.8
1.5.7
-
-
-
-
-
-
-
-
-
100.0
Total
.8
10.6
10.2
1.7
.6
.8
4.5
2.9
1.1
5.3
2.0
1.1
48.3
2.9
4.0
3.2
100.0
>£»
'September, 1978 cost levels,
-------
TABLE 22. SUMMARY OF 440 1/S (10 mgd) TYPICAL PLANT COSTS,
(Thousand Dollars)
Structure
Buried rectangular structures
Preliminary treatment
Primary sedimentation
Activated sludge
Disinfection
Subtotal
Item cost as percent of
plant subtotal
Item cost as percent of
plant structural
Buried circular structures
Secondary sedimentation
Item cost as percent of
plant subtotal
Item cost as percent of
plant structural
Aboveground circular
structures
Grax'ity thickening
Anaerobic digestion
Subtotal
Item cost as percent of
plant subtotal
Item cost as percent of
plant structural
Buried deep structures
Influent pumping station
Item cost as percent of
plant subtotal
Item cost as percent of
plant structural
Sludae pimping
Vacuum filter facilities
Miscellaneous structures
Subtotal
Item cost as percent of
plant subtotal
Item cost as percent of
plant structural
All structural types
Subtota !
Item cost as percent of
plant subtotal
Item cost as percent of
p'ant structural
Earthwork
14
16
123
23
176
3.7
-
41
,9
11
26
37
.8
57
1.2
4
3
7
.2
318
6.6
-
Base
slabs
10
74
126
17
227
4.7
10.1
95
2.0
4.2
11
23
34
.7
1.5
35
.7
1.6
50
19
69
1.4
3.1
460
9.6
20.5
Suspended
slabs
13
6
19
.4
.8
4
4
.1
.2
35
.7
1.6
12
19
31
.7
1.4
89
1.9
4.0
Structural
Poured
vertical
23
86
238
30
377
7.9
16. B
107
2.2
5.8
11
132
143
3.0
fi.4
100
2.1
4.4
-
727
15.2
32.4
Y-walls
-
86
-
86
1.8
3.8
61
1.3
2.7
11
11
.2
.5
-
158
3.3
7.0
Precast
vertical
27
27
.6
1.2
24
.5
1.1
62
58
120
2.5
5.3
171
3.6
7.6
Hoppers
21
21
.4
.9
11
.2
.5
1
1
.1
.1
-
-
33
.7
.6
Piers
7
4
11
.2
.5
-
2
2
.1
.1
-
-
13
.3
2.4
Cross
beams
13
24
-
37
.8
1.7
16
.3
.7
-
53
1.1
9.1
Covers
_
-
-
16
188
204
4.3
9.1
'-
204
4.3
14.9
Other
5
3
101
6
115
2.4
S.2
25
.5
1.1
39
39
.8
1.7
74
1.6
3.3
59
21
80
1 .7
3.6
333
7.0
Mechanical
vlajor
Bl
149
286
55
571
12.0
348
7.3
48
178
226
4.7
119
2.5
37
227
-
264
5.5
1,528
32. n
Other
18
57
31
27
133
2.8
95
2.0
-
9
10
19
.4
257
5.4
57
130
187
3.9
691
14.5
Total13
151
426
1,032
191
1,800
37.7
799
16.7
120
600
720
15.1
701
14.7
37
471
250
758
15.9
-
4,778a
100.0
100.0
Plant. total cost=-?lant subtotal + Piping, 10%+
:= 4,778+ 478+ 382+ 239 + 239
Differences in item costs exist between
Electrical, 8%+ Instrumenta
= $6,116
this- table and tables 17
tion, 5% + Site preparation, 5%
through 21 due to rounding.
95
-------
TABLE 23. CONDENSED SUMMARY, TYPICAL PLANT
STRUCTURAL COSTS AS A PERCENT OF TOTAL
PLANT STRUCTURAL COST, 440 1/s (10 mgd)
Buried rectangular
structures
Buried circular
structures
Above ground cir-
cular structures
Buried deep
structures
Precast concrete
structures
Combined costs for
all structural
types
Earthwork
6.9
1.6
1.6
2.2
0.3
12.4
Base and
suspended
slabs
9.6
3. 7
3.7
2.7
3.9
21.4
Vertical
walls:
poured, Y
and precast
19.2
6.6
6.6
4.9
4. 7
41.4
Hoppers,
piers and
cross
beams
2.7
1.0
1.0
-
-
3.8
Covers
-
-
-
-
-
8.0
Structural
4.5
1.0
1.5
2.9
3.1
13.0
COST CENTERS
From Table 23, it is evident that vertical wall construc-
tion of various types accounts for some 40 percent of total
treatment plant structural cost. Vertical walls for buried
rectangular/circular structures alone account for almost 20
percent of total costs. Various slabs account for 20 percent
of total cost, with buried rectangular/circular types again re-
presenting nearly half. Other notable values from this table
are 9.0 percent of total cost for digester covers and some 8.5
percent for excavation and earthwork costs for buried rectangu-
lar/circular structures.
Table 22 gives similar conclusions to Table 23, in more
detail, and unit-by-unit. The relative costs of mechanical
equipment to total plant costs can be seen here. Thirty-two
percent of total costs relates to major mechanical equipment,
14.5 percent relates to other items of mechanical equipment.
The total cost of these two items approaches 50 percent of total
plant cost. Based on an assumption that potential cost savings
are proportional to present cost, it is apparent that mechanical
equipment offers a promising area for potential cost savings.
A discussion of factors impacting the cost of mechanical equip-
ment may be found in Section 4 of this report.
96
-------
The remaining tables (17 through 23 and Appendix A) show
interesting detail trends. The lower relative cost of formwork
to concrete for below ground versus above ground structures is
apparent if Tables 17 (influent pump station) and 20 (anaerobic
digesters) are compared. This represents the difference between
the more massive underground structure where finish is rela-
tively unimportant and the thin walled abovegrade structures
where finish for visual appearance is of prime concern. Table
21 (vacuum filter facility) indicates a similar aboveground
structure trend except that the concrete item is high. Inspec-
tion of the table reveals that over 60 percent of the concrete
item relates to off-site fabricated precast panels for which
no on-site forming and little concrete labor is required.
Similar trend information anomalies, and the reasons for
them, can be developed by reviewing and comparing the tables.
The data, in its present form, provides a useful guide to de-
signers by providing a means of altering the Engineer to the
impact of design decisions. However, since each wastewater
treatment project is unique because of various site, environ-
mental and process considerations, we do not believe firm con-
clusions or recommendations can be drawn from the data. We do
believe, however, that the data, in reduced form should be made
generally available for use as an aid to designers.
The cost center analysis proved useful in identifying areas
having potential for cost savings using unconventional or novel
methods or materials of construction; the analysis pointed to
some non-structural elements as well, particularly as related
to procedures used in specifying mechanical equipment.
97
-------
REFERENCES
9. 1976 Dodge Guide to Public Works and Heavy Construction
Costs.
10. Technical Report MCD-38 "Construction Costs for Municipal
Wastewater Conveyance Systems, 1973-1977".
98
-------
SECTION 6
UNCONVENTIONAL METHODS AND MATERIALS OF CONSTRUCTION
UNCONVENTIONAL METHODS AND MATERIALS
For the purposes of this report, unconventional methods
and materials of construction are those which, though not rou-
tinely employed, have been proven or at least demonstrated in
actual installations. In contrast, novel methods and materials
are those which represent promising new approaches to reducing
the cost of wastewater conveyance and treatment facility con-
struction.
This section describes the results of the search to identi-
fy unconventional methods and materials of construction. A
selection of unconventional methods and materials are described
in the latter part of the section. The format selected for
these individual reports is intended to make them useful as a
reference section. Areas of application are highlighted so that
a reviewer may easily determine whether or not an idea might
apply to a particular situation.
RESEARCH
Computer Searches
Research into unconventional methods and materials of con-
struction was initiated using computer search assistance. EPA,
in formulating the scope of the project, undertook several com-
puter searches. This research path was continued, developing a
search program, which is included as Appendix C. Authors of
articles which deal with novel and unconventional methods and
materials of construction do not necessarily term them as such.
Key words used in searches for these items were therefore de-
veloped to try to identify novel and unconventional items di-
rectly. Pairing key words to link, for example, treatment pro-
cess units with such terms as "economic analysis", "value engi-
neering" and "efficiency" was attempted.
The computer printouts generated by these searches were
subjected to careful scrutiny. The first review was always
undertaken by an experienced engineer, who eliminated unrelated
99
-------
references. Potential references were then located by staff
members, copied and reviewed again by experienced engineers.
The process was extremely barren; of over a thousand items re-
viewed, less than ten provided useful study input.
Contractor Contacts
During contacts with construction contractors to develop
input for the nonstructural phase of this study reported in
previous sections, questions were raised concerning novel and
unconventional methods and materials. The general response was
that novel and unconventional ideas were rapidly applied by con-
tractors to improve the inventor's bidding position. No novel
ideas were suggested, but several unconventional ideas were
identified.
Other Contacts
Various other contacts were made. Industrial associations,
mechanical equipment suppliers, engineers, treatment plant op-
erators and others were solicited for ideas. Several more use-
ful ideas were gained from these efforts.
Results
A number of unconventional ideas suggested were not con-
sidered since they related to equipment or process ideas. Many
ideas showed promise in the area of process improvement or op-
erational cost reductions, but were considered outside
the terms of this study. Finally, a selection of unconventional
ideas was agreed upon as appropriate to the study theme. Each
of these ideas were then examined in more depth. Some were sub-
sequently rejected because they were not effective in reducing
capital cost; these are listed in Appendix B.
The remaining unconventional methods are included in this
section. Each is described in terms of concept, application,
description, advantages, and disadvantages and costs. In some
instances, for example, "sewer-within-sewer", no comparative
data were available, but potential cost savings are apparent.
Nine potentially cost-effective unconventional methods are
identified and are described in following paragraphs:
• Insituform pipe liners
• Trenchless sewer pipe installation
• Sewer-within sewer
• FRP piping
100
-------
• FRP bridges
• Plastic fluid control equipment
• Miscellaneous FRP items
• FRP digester covers
• Unconventional covers and enclosures.
Ideas delegated to Appendix B by virtue of their inability
to pass the capital cost reduction test were:
• Ozone generation
• Shotcrete
• Concrete dome covers
• On-site wound FRP tanks.
POTENTIALLY COST-EFFECTIVE UNCONVENTIONAL METHODS
Insituform Pipe Liners
A new approach to sewer pipe relining is a flexible poly-
ethylene liner that is cured insitu. It supports deteriorated
sewer lines and seals against infiltration of groundwater. The
process was developed in England where several installations
exist.
Applications—
Generally, the insituform pipe lining method may be used to
achieve the following:
• Reduce infiltration
• Repair weak or structurally unsound sewers
• Reline brick sewers to improve capacity.
Description—
Two different techniques are used to install insituform
pipe liners, depending on whether sewage diversion or overpump-
ing is possible (inversion technique) or not (flow through
technique).
The flow through process of insituform lining involves
inserting a tube of terylene felt into a sewer pipe of slightly
larger diameter. The liner is inflated with low pressure air,
followed by steam. The liquid polyester resin that totally
101
-------
impregnates the felt cures because of the increased temperature
in four hours. The resultant shell is 3-19 mm (1/8 - 3/4 in)
thick with properties similar to glass reinforced plastic.
Flow is maintained through the curing process by the use of
an inflation bag. This is a double skinned reinforced poly-
vinylchloride tube which is placed inside the impregnated felt
tube. Air is blown between the PVC skins, collapsing the inner
layer, expanding the outer layer and pushing the impregnated
felt against the sewer wall until the water forces its way
through the middle of the bag.
Cement grout can be injected behind the liner to fill in
the voids and consolidate the sewer. The flow from lateral
sewers is intercepted and pumped to the next manhole until the
inflation bag can be withdrawn and the laterals cut out. In
smaller diameter sewers, the laterals are located by television
camera and cut out with a remotely controlled drogue.
The terylene felt is relatively inexpensive as it is made
up by a needling process from waste fiber. Impregnation is
carried out at the factory by enclosing the felt in an inner
and outer polyethene skin and applying catalyzed resin under
vacuum. The linings are transported under refrigeration.
It is possible to line pipes from 102 mm (4 in) up to
1,220 mm (48 in) diameter. The work is usually carried out
through normal manhole openings using lengths of up to 122 m
(400 ft).
The inversion technique is used when flows can be over-
pumped or diverted. This process is also appropriate for sewers
that are too small for access. A resin impregnated felt tube is
enclosed in a sheath of polyurethane film and fed through a
vertical inversion pipe with a 90-degree bend at the bottom.
The tube is turned inside out over the ends of a horizontal
spout and clamped to the end of the inversion pipe. Water is
then pumped into this pipe. As heat builds up the lining turns
inside out. Hot water (75 C) is circulated to cure the resin;
a process which requires about two hours.
Advantages—
The insituform technique provides the following benefits:
* Increases flow coefficient
• Chemically resistant to most chemicals found in
wastewaters
• Abrasion resistant
* Maintenance free
102
-------
• Conforms to contours of distorted sewer line
• Supports old sewers from collapse and prevents
scouring of mortar jointing
' Rapid and simple installation, no excavation
* Small reduction in cross-sectional area of pipe.
Research is currently being carried out on a system for
inverting resin felt lining into a new sewer with a reusable
polyurethane tube. The concrete sewer is sprayed with a non-
catalyzed resin which bonds to the catalyst contained in the
felt.
Disadvantages--
Only sparse data have been collected on the performance of
this system in the variety of environmental conditions which
commonly prevail in wastewater collection systems. The material
is not adequately resistant to plating wastes, for example.
Hence, this technique may not be suitable for use in industrial
sewers. In our judgement, careful attention to detail is re-
quired during application, or the possibility exists that the
curing process may not be accomplished properly.
Cost Data—
The insituform technique is appropriate for repair of
existing sewers, where it may be used to correct excessive in-
filtration or strengthen failing pipe. Comparative cost data,
based upon hypothetical situations, therefore, are meaningless.
The cost of repair or replacement or remedial measures, such as
soil grouting for control of infiltration, must be compared
directly against the cost of the insituform method on a site
specific basis because of the many variables to be encountered.
With due consideration of the disadvantages noted above, it
would appear that insituform pipe liners may offer promising
economic advantages.
Trenchless Sewer Pipe Installation
A recent EPA demonstration grant project has successfully
shown that installation of sewer pipe to accurate grade and
alignment is possible with trenchless pipelaying equipment.
European engineers have considerable experience with installa-
tion of drainage pipes, pressure pipes and conduit.
Applications—
Possible uses in the EPA grant program include:
* Installation of small diameter sewer pipelines
and house connections
103
-------
• Installation of conduit and small pressure
pipelines in rural areas of treatment plant
projects.
Description—
A vertically fixed, modified plough blade cuts the ground
to the required depth. The sewer pipe is connected to the
blade's toe and pulled through the cavity generated by the
plough. A pointed steel shield protects the leading end of the
pipe. Capabilities exist for installing pipe up to 22 inches
in diameter to a depth of 9 feet, assuming relatively consistent
soil conditions.
Vibratory plowing equipment, a somewhat different design
from that used in the EPA demonstration, is available in the
United States for trenchless underground pipe installation. A
plow blade with a vibrating compactor tip is used to pull con-
tinuous lengths of pipe into place. Pipe up to 4 inches in
diameter may be placed 36 inches underground with this equipment.
Vehicles equipped with vibratory plowing equipment can lay pipe
in highly manicured areas, such as golf courses, without having
unsightly trench or wheel scars.
Advantages--
• Surface disturbance is less than by conventional
construction, hence restoration costs will be less,
• Installation speeds can be greater than by con-
ventional construction, hence cost savings.
Disadvantages—
At present, the following are the major disadvantages of
trenchless sewer construction:
• Machinery is currently available only in England
and Germany, and is expensive to build and ship,
* Limiting pipe size and ground conditions,
• Limited availability of specialized pipe laying
equipment,
• Soil conditions will dictate results: Well con-
solidated soils, boulders, high ground water
table, etc., will cause problems.
Cost Data—
Potential cost savings are discernible in favorable soil
conditions, and where small diameter pipe can be laid accurately
and rapidly with the right machinery. In the only known U.S.
demonstration project, sponsored by EPA, the trenchless sewer
method proved more cost-effective than conventional methods. On
104
-------
the basis of the actual bid price, for 20.3 cm (8 in) polyvinyl-
chloride (PVC) gravity sewer mains, installed cost using conven-
tional methods was $49.21 per lineal meter ($15 per lineal foot),
while installed cost for trenchless areas was $29.33 per lineal
meter ($9 per lineal foot). On the basis of computed costs for
complete PVC sewer installation, including wyes, manholes and
laterals, the costs per lineal meter for conventional and trench-
less systems were $75.90 and $63.57 ($23.15 and $19.39) respec-
tively. Concerning labor only, the computed cost differential
was $2.76 per lineal meter ($.84 per lineal foot) in favor of
the trenchless method. •L
Sewer-Within-Sewer
Many of the nation's metropolitan areas are served by com-
bined sewers. While the need for separation of these systems is
obvious, progress has been slow because of the enormous costs
associated with sewer construction in congested areas. The
sewer-within-a-sewer technique, where the sanitary sewer is in-
stalled within the existing storm sewer promises to be an eco-
nomical solution in at least some areas.
Applications--
In the case history described below, a gravity sewer was
installed within an existing, large diameter combined sewer,
realizing large savings over more traditional approaches to the
sewer separation problem. The technique could be applied as
well to pressure sewer systems, if that type of installation was
found to be more cost effective, as indicated in EPA-R2-72-091
and Status of Pressure Sewer Technology by James F. Kreissl.
Description—
In a previous application of this technique,12 a 14 inch
diameter, asbestos-cement, sanitary sewer was laid in the invert
of an existing combined sewer; a 60 inches high by 40 inches
wide, elliptical, cast-in-place, concrete pipe. Total length
involved was approximately 1,800 feet. The sanitary sewer pipe
was placed into position (one 8 foot section at a time), working
manhole to manhole along the length of the combined sewer. Pipe
sections were connected with pressure joints.
Sanitary leads from buildings along the route were tapped
into the new sewer using 6 inch diameter asbestos-cement pipe
and fittings. The new leads were routed along the interior wall
contour of the old pipe, and were fastened to the pipe wall
using stainless steel straps and anchors. The sanitary leads
were then covered with gunite to provide protection and to keep
turbulence to a minimum. A quick-set mortar sealant prevented
leakage of sanitary sewage into the storm sewer during construc-
tion.
105
-------
Each 400 foot section of sanitary sewer pipe installed in
the manner described was then concreted over to a depth of two
inches with 3,500 psi concrete. In this particular installa-
tion, the invert of the new storm sewer formed by this process
was considerably flatter than that of the original combined
sewer. A wooden screed cut to ride the pipe walls at the de-
signed depth kept the covering uniform. Cleanouts were in-
stalled through the concrete invert at each deep manhole to al-
low for flushing by high pressure water.
Entrance to the combined sewer was made via shafts sunk at
street intersections: the shafts were located at the sites
where sanitary laterals emptied into the old combined sewer
manholes. These laterals were dead-ended into their own man-
holes, and the manholes then sewered into the new sanitary sewer.
Advantages--
The following advantages were cited for the referenced in-
stallation: -*-3
• Substantial savings in cost (a reduction from $600,000
to $200,000) over traditional methods of sewer in-
stallation involving open-cut or tunneling techniques,
* Reduced inconvenience to downtown traffic, businesses
and shoppers,
* Reduced sanitary sewer maintenance problems because
the sewer pipe is not subjected to the loads, etc.,
experienced by a conventional sewer line,
* Construction produces minimum disruption to the
existing sanitary system and the utilities.
Disadvantages--
The installation of the sewer within an existing storm
sewer will reduce the storm sewer's cross-sectional area and,
thus, its capacity. In the instance cited, the sewer was in-
stalled in the invert of the existing sewer and a new invert was
formed with concrete, possibly causing future maintenance pro-
blems because of reduced velocities at low flow. Some of these
drawbacks could potentially be avoided by installing the new
sewer in the crown of the storm sewer; where the elevations of
existing sanitary sewer laterals permit, interception system can
be justified.
The technique is limited to instances where a relatively
large diameter (60 inches or larger) existing sewer is avail-
able, and only modest quantities of sanitary wastewater must be
accommodated.
106
-------
Fiberglass Reinforced Polyester Applications
Fiberglass reinforced polyester (FRP) piping systems are
becoming more prevalent and quality control is improving. Prop-
erly engineered, FRP systems can be used to overcome problems
caused both by corrosive soils and corrosive liquids in waste-
water systems.
Applications--
Specific applications for FRP piping systems include:
• Sewerage systems carrying high-temperature,
acidic, alkaline wastewaters, or corrosive
gases,
* Sewerage systems in corrosive soils,
* Process piping systems for corrosive chemicals
or gases,
* Sewerage systems where pipe flexibility and
reduced installation time is important,
* Sewerage systems in cold climates.
Description—
Fabrication of FRP pipe system materials consists of form-
ing a laminate by combining controlled amounts of epoxy or poly-
ester resin and catalyst with fiberglass mat, cloth, woven rov-
ing, filaments or synthetic fibrous material. Successful use of
FRP depends upon proper selection of materials (resin in parti-
cular) , particular attention to details of construction, and
proper methods of fabrication, Typically, care must be exer-
cised to insure that proper protection is provided for the rein-
forcing filaments through selection of protective veils and
resins. Veils should be included in any laminate subject to
immersion in liquids, or used for the conveyance of liquids, to
protect against migration of liquid along the reinforcing fila-
ments, and destruction of the bond between the filaments and
resin. FRP laminates can be constructed by either hand layup,
contact molding or filament winding techniques. Of those three
methods, filament winding, which is limited to circular or el-
liptical sections, provides the strongest construction and the
advantages of quality control measures which can be more, rapidly
applied to machine-made products. The precision filament-
winding process integrates the lightweight materials into one
unitized high-strength piping structure. FRP is assembled and
installed using flanges or a chemical-resistant adhesive for
joining. Joints may be rapidly installed and are as strong as
the original pipe. No costly pipe threading or welding is
involved.
107
-------
In Hillsborough Cpunty, Florida, FRP manholes and pump
Station wet wells are being used to combat severe hydrogen-
sulfide corrosion in a municipal sewerage system. One 13 ton
FRP wet well 2,340 mm (92 in) in diameter-and 7.5 m (25 ft) in
length was lifted whole and set on a concrete base at ground
level. Laterals and cover were added after installation. At
another site, a 1,020 mm (42 in) ID section of FRP pipe was used
as a manhole liner to repair deteriorated bric,k manholes.14
At a wastewater treatment plant in California,-a 1,220 mm
(48 in) diameter pipe was selected by the contractor for use on
a buried foul air duct because its overall cost was less than
plastic lined concrete pipe.
Advantages—
Corrosion control is excellent due to resistance to both
chemical and biological attack. FRP offers flexibility and
toughness and is easily cut to size. Except for stiffness, FRP
strength characteristics compare favorably to carbon steel or
aluminum. Most of this comparable strength can be provided at
weights which,are only a fraction of that necessary using steel
or concrete. Time and cost of pipe installation are reduced
substantially due to the light weightr ease of handling and in-
stallation, longer pipe lengths (fewer joints), lower labor and
construction costs. FRP exhibits low thermal conductivity, is
nonconductive, and will not collect stray ground currents which
may corrode other equipment. Total energy requirements to pro-
duce a ton of FRP are less than that required to produce a ton
of steel.15 Manufacturers claim that FRP life-cycle cost is ap-
proximately equal to that of mild steel with some form of coat-
ing for protection, and is about one-half the cost of stainless
steel and one-fifth the cost of rubberlined steel.
Disadvantages—
FRP may often have a higher price or first cost than com-
petitive materials. These differences are usually offset, how-
ever-, by savings in s-upport structures, installation costs, etc.
Laboratory or field tests irtay be necessary to determine the cor-
rect resin and veiling system for each application. Without
specific protection,- FRP can be subject to degradation under
strong ultraviolet light from sunlight or fluorescent lighting.
When immersed in liquids., the material may delaminate if all
exposed edges are not completely sealed with resin. Since fab-
rication often requires hand processing,allow for the possibili-
ty of human error. At some stres-s below its ultimate burst
strength, FRP piping can-"weep" or transmit fluid through the
pipe wall without showing visible cracks. Reinforced plastics
do not have^ definite temperature and pressure limits. Care must
be used to adequately compensate for thermal expansion and
contraction.
108
-------
Care must be used in the selection and specification of FRP
pipe for buried applications. Poorly designed or installed ap-
plications can result in cracking of the protective resin from
both ring and beam tension. These cracks can lead to exposure
of the reinforcing filaments to hostile environments and ulti-
mate failure of the pipe. Several failures of reinforced plas-
tic mortar (RPM) pipe, a variation of FRP construction, have
been attributed to this cause.
Cost Data—
It is reported that two wastewater treatment plants claim
50 percent cost savings in labor and material of fiberglass
reinforced plastic pipe in lieu of glass lined cast iron for
sludge, sludge gas and scum systems.16 It is also reported that
another wastewater treatment project claimed 35 percent savings
by using FRP suspended piping in lieu of conventional materials,
such as cast iron and steel.17
Fiberglass Reinforced Polyester Bridges
A box type design walkway bridge of fiberglass reinforced
polyester (FRP) material is claimed by manufacturers to be
cheaper than steel installed costs as well as substantially
cheaper in life cycle costs.
Applications—
Specific applications for this type of bridge at a waste-
water treatment plants include:
* Walkways on circular clarifiers and gravity
thickeners,
• Access bridges between adjacent structures,
• Access bridges for surface and turbine aerators
in aeration basins and oxidation ponds.
Description—
The bridge is constructed of a high-strength continuous-
fiberglass reinforced laminate which is 1/3 as dense as steel.
It is pre-engineered in one piece according to specifications
and is designed to be bolted in place. Generally custom fabri-
cated, these structures can be equipped with a variety of ap-
purtenances for various needs. Manufacturers claim that the
bridge can meet OSHA requirements at all times without periodic
checks for safety hazards.
Advantages—
The main advantage of FRP bridges is its low capital and
operating costs. In addition, the following benefits may be
realized with FRP construction:
109
-------
• Lower installation costs, because of its lighter
weight,
• Color is impregnated into the laminate, maintenance
painting is not required,
• Non-corrosive construction,
• Non-sparking construction, suitable for hazardous
environments.
Disadvantages—
As with all FRP construction, care should be exercised in
the selection of resins and other construction details. Mechan-
ical damage to the laminate could expose the reinforcing fila-
ments to the elements and corrosive chemicals. Repairs and/or
modifications to the structure must be made with care by techni-
cians skilled in this type of construction. Since the material
is relatively new, there is uncertainty with respect to the ef-
fects of ageing (creep, embrittlement, etc.) and its overall
impact on useful life.
Cost Data—
A 21 m (70 ft.) FRP bridge is estimated to cost $9,450 in
place. A steel bridge of the same length will cost about
$17,830. This information is based on November, 1977 prices.
Plastic Fluid Control Equipment
With the advent of modern technology came the development
of plastic construction materials and their utilization in fluid
control equipment. A variety of plastics have been developed
specifically for use in wastewater and water treatment projects.
These products have structural and corrosion resistant proper-
ties which apparently make them ideally suited for wastewater
treatment applications.
Applications—
Applications for advanced technology plastics in wastewater
treatment include the following:
• Sluice gates,
• Slide gates,
• Stop gates or stop logs,
• Rigid or flexible non-return flap gates,
• Horizontal or vertical splitter gates,
• Weir plates, scumboards and baffleboards.
110
-------
Description—
A rigid compressed composite plastic, with ultra-vilolet
light inhibitors and extremely high tensile and impact strength,
is used as the outer sandwich on sluice gates, stop gates, flap
valve discs, weir plates, and scum baffles.
High pressure, wall mounted, watertight sluice gates are
available in a range of sizes with upward or downward opening
gates and with square, rectangular or circular openings. A
flush invert provides for a straight-through self-cleansing
flow, eliminating grit pockets and reducing turbulence. The
recommended maximum working head is 4 m (12 ft.); however,
special units may sustain a higher working head.
Sluice gate frames can be fabricated of stainless steel or
mild steel (sandblasted, flame zinc sprayed, etch primed and
finished with epoxy paint) to provide corrosion resistant quali-
ties consistent with those of the disc. The stem is a single-
start stub-acme thread machine cut from ferrous or non-ferrous
materials. The stem nut is machine cut from high molecular
weight polyolefin, which has both strength and low coefficient
of friction. Sluice gates fitted with a rising stem have the
nut housed in the handwheel while those with the non-rising
stem have the nut fitted in the disc.
The patented sluice disc sealing arrangement consists
of polyolefin sealing faces and side guides with a resilient
backing strip of specially expanded neoprene. The discs are
factory preadjusted but can be easily readjusted on site at any
time. All contact faces are made in materials selected for
smooth and easy operation.
Advantages—
Plastic construction, as described above, offers the fol-
lowing advantages:
• Greatly reduced thicknesses and weight results in
lower handling, installation and operation costs.
Simpler construction and less area requirements
also result. (Channel wall thickness may be re-
duced by 60 percent.)
• Non-toxic, smooth corrosion-free surfaces result
in low maintenance and long life equipment which
is not affected by and does not affect most chemi-
cal processes. Surfaces require no painting and
are resistant to fungus, and algal and marine
growths.
• Low friction in moving parts results in less physi-
cal effort for manual operation, smaller hand
wheels, and smaller and less costly electric actuators.
Ill
-------
• Low thermal expansion properties result in equip-
ment that will not buckle or warp.
• Material is self-extinguishing, hence resistant
to damage by fire.
• Satisfies AWWA specifications for water tightness.
Disadvantages—
Plastic construction could be a disadvantage in systems
where high concentrations of solvents may be present in the
wastewater.
Cost Data—
According to information furnished by the manufacturer,
lower capital and installation costs for plastic fluid control
equipment will result in savings of up to 20 percent over cast
iron equivalents. While operating costs may be reduced some-
what, because of smaller operators, this impact will be minimal.
Maintenance costs may be expected to be equal to or less than
those associated with conventional sluice gate construction.
Miscellaneous FRP Uses for Wastewater Treatment Plants
Fiberglass reinforced polyester (FRP) construction for
various elements commonly found in many waste treatment facili-
ties may offer substantial benefits in both installed and over-
all costs. Although it is an emerging engineering material, FRP
is worthy of serious consideration in a variety of applications.
Applications--
FRP could be used for the fabrication of various items
typically found in wastewater treatment applications, including:
• Weir plates, effluent launders, and scum baffles,
• Metering flume liners,
• Cabinets and shelters,
• Walkway grating,
• Supports for biofilter media,
• Chain and flight sludge scrapers for rectangular
sedimentation tanks.
Description—
Laminates of resin and fiberglass reinforcing material can
be made in any shape desired and to fit most chemical and tem-
perature environments. Given sufficient knowledge of expected
service conditions, resins and reinforcing materials may be
112
-------
selected to tailor a laminate to specific needs. Production may
be of special fabrications or standard products; again depending
upon specific service requirements. Standard products enjoy the
greatest cost saving potential.
Depending upon the nature of the corrosion protection sys-
tem specified for fabricated steel, weir plates, effluent
launders, and scum baffles, these items, manufactured in FRP,
can be equal or marginally cheaper in cost. A major advantage
of FRP elements, however, lies in lower maintenance costs when
compared to steel. Assuming proper attention to details, such
as structural loads, corrosion resistance and proper protective
systems for the reinforcing filaments, FRP laminates may be ex-
pected to be virtually trouble free.
FRP laminates are used increasingly to provide permanent
formwork for complex shapes, such as metering flumes. Cost sav-
ings of zero to 25 percent is possible over similar wood formed
shapes. A more important consideration is the increased degree
of precision obtained by using a correctly reinforced permanent
form. This latter factor is of particular significance because
of the requirements necessary to insure accurate metering
facilities.
Free-standing, weatherproof cabinets and shelters construc-
ted of FRP are becoming more readily available for the enclosure
of electrical equipment,emergency generators, pumping station
superstructures and substructures, and fuel tanks, etc.
First cost savings over mild steel enclosures are possible
provided standard sizes are adopted to permit permanent
molds to be used, and provided that the mild steel is
coated with a high quality corrosion protection system, and
miscellaneous hardware are of non-corrosive metals. FRP enclos-
ures can be substantially cheaper than permanent construction in
these areas.
FRP grating, offering superior corrosion resistance, is
available in a variety of off-the-shelf shapes and load carrying
capacities. In addition, FRP grating has been used as a support
system for synthetic media in biofilters. The grating is placed
on a concrete subframe, forming a load-carrying platform for the
media. Ease of installation plus no requirement for corrosion
protection make FRP more economical under these conditions than
comparable materials such as steel or concrete.
Fiberglass flights and thermoplastic chains are claimed to
be lower in cost, and offer superior resistance to severely cor-
rosive operating conditions of sludge collection service. The
weight savings over the conventional metal chain and redwood
flights could result in lower operating and maintenance costs
through reductions in energy consumption and wear.
113
-------
Advantages--
In addition to those qualities indicated above, the non-
corroding, non-conducting and thermal insulating characteristics
are three of FRP's foremost advantages. Its light weight fre-
quently permits relatively convenient installation, which in
turn results in lower costs. Assuming proper design and fabri-
cation, the structures require no painting and minimal mainte-
nance.
Disadvantages—
Since relatively little capital investment and only a mod-
est degree of training are required for an individual to enter
the FRP fabrication business, quality control can be a substan-
tial problem. At present, only a few standards, such as
National Bureau of Standards' Voluntary Product Standard PS-15,
are available for the use of the specifier. The industry lacks
any recognized standards setting organization, such as the
National Electrical Manufacturer's Association in the electrical
industry. FRP has consequently gained a relatively poor reputa-
tion in some circles. Until such time as specific standards are
published and some type of effective quality regulation system
is placed into effect, utilization of FRP laminates in the
public works industry must be done cautiously, with rigid,
owner-established and enforced quality control programs. This
type of control will inevitably increase costs and reduce the
attractiveness of the material.
Cost Data—
Comparative cost data are not generally applicable. An
extreme variability of application and specification require-
ments between individual projects exists. As standards are es-
tablished, and standard products developed, costs should become
more competitive with conventional engineering materials. At
present, FRP products tend to be cost-effective where special-
ized specific applications occur.
Fiberglass Reinforced Polyester Digester "Covers
Fiberglass reinforced polyester (FRP) tank covers, either
floating or fixed, are now available at a lower installed cost
than conventional steel covers used with digesters.
Applications--
FRP covers are manufactured in four styles. Analagous to
their steel counterparts are the FRP fixed, floating and float-
ing gas holder (FGH) styles. The fixed FRP cover is a ribbed
dome rigidly attached to the top of the digester tank walls.
Floating FRP covers have a ballasted perimeter collar which
floats on the tank contents and moves in well slides. A sub-
merged ceiling plate mounted in a dome attached to the ballast
collar helps control scum accumulations. The floating gas
holder is of similar construction, except that it does not have
114
-------
a ceiling plate. Recently, a new type of cover was developed
called the constant pressure (CP) cover. This unit, shown in
Figure 7, consists of the domed (fixed or floating) cover, with
an internal ballasted neoprene membrane designed to maintain a
constant gas pressure. The design allows more usable gas to be
stored within the digester.
Advantages—
FRP covers offer the following principal benefits:
• Lower installed costs. See Table 24.
• Greater volume of gas at usable pressure (FRP-CP
type). See Table 24. This could eliminate gas
storage and compression equipment at some plants.
• Better insulation properties.
• Less maintenance, corrosion free.
Disadvantages—
Presently, the specifier has only a few standards available
to him, such as National Bureau of Standards Voluntary Product
Standard PS-15. This is a consequence of the industry's lack of
any recognized standards setting organization; such as the
National Electrical Manufacturer's Association in the electrical
TABLE 24. COMPARISONS OF DIGESTER COVER
COSTS AND USABLE GAS VOLUMES
Type
40'ij> FRP-CP
40 '$ FRP-FGH
40'<]> Steel- floating
40'<|> Steel-FGH
90 '$ FRP-CP
90' Steel-FGH
Installed cost*t
41,000
63,000
58,000
63,000
165,000
214,000
241,000
250,000
Usable gas -
percent
100
75
3
33
100
75
2
21
* Does not include, mixing equipment.
t Based on November 1977 prices.
115
-------
T
f. SLIDING CENTER
I STACK (HIGH POSITION)
GUIDE ROLLERS
COMPRESSION RING &
STACK GUIDE
DIAPHRAGM HIGH
POSITION (MAX. VOLUME)
Jl
—
; — ^^
— «••
ffi)
•
— •-
~ -
t
PRESSURE RELIEF & VACUUM
"BREAKER W/FLAME ARRESTER
GAS OFF FLANGE
STANDARD FRP
COVER
DIAPHRAGM LOW POSITION
(MIN. VOLUME)
STACK (LOW POSITION)
FIGURE 7. CONSTANT PRESSURE DIGESTER COVER
References
Rysgaard, John Jr. and Gregg, Ted, personal communications,
representatives of Fiberglass Specialties Company.
Holsen, Larry, personal communication, representative of
Envirex, Inc.
116
-------
industry. By virtue of the relatively low capital investment,
and modest degree of training required of an individual to enter
the FRP fabrication business, quality control is a problem. As
a result, FRP has obtained a poor reputation in some circles.
It seems apparent that until specific standards are published.
and an effective quality regulation system put into working
order, utilization of FRP laminates by the public works industry
must be done with caution by rigid, owner-established and en-
forced quality control programs. Unfortunately, this kind of
control will have the inevitable result of increasing the cost,
while at the same time reducing the attractiveness of the ma-
terial. Since the environment in and around anaerobic digesters
presents some unique problems, special care must be employed
when selecting resins, veils and construction details.
Cost Data—
Cost data for 40 foot and 90 foot diameter examples are
provided in Table 24.
Unconventional Covers and Enclosures
Rising community expectations and regulated standards for
WWTP design in some areas have necessitated that many process
units be covered or totally enclosed. Several varieties of
covers and enclosures are more economical than conventional
concrete or steel truss units.
Applications—
Applications include the following:
* Odor containment over any size process tankage,
• Containment and recycle of generate.d process
oxygen or ozone,
• Drying bed covers,
• Equipment covers,
• Architectural treatment.
Description—
FRP circular covers are domed structures ribbed with struc-
tural reinforcement. The covers are fabricated with the exteri-
or surface against the mold to provide a smooth, dimensionally
stable finish. A protective gelcoat resin prevents ultraviolet
deterioration. Windows, entry doors, fan housings, equipment
pads, etc. are integrally molded into the dome in such a manner
that the structural integrity of the cover is not compromised.
Resins may be tinted to provide full depth color. Gasketed
panel sections can be gas tight.
117
-------
Aluminum circular covers are geodesic domes, consisting of
structural frames and skins. A wide variety of architectural
finishes are available. They are attractive and extremely
lightweight. Aluminum frames may be provided with either ex-
ternal permanent skins, or form a space frame around a fabric
cover which can be opened when desired. FRP covers for rectan-
gular openings come in many varieties. FRP covers are available
in flat, ribbed-flat, ribbed-arch, arch and half-barrel config-
urations, as illustrated in Figure 8. These shapes accommodate
different loadings and transmit different forces to the founda-
tions. For all span widths, rounded or arched covers can have
thinner cross sections than flat covers and hence are more eco-
nomical. Openings and holes of any shape can be provided with
custom FRP covers. In short spans, concrete lift slabs may be
as economical as FRP covers, but the FRP covers have the advan-
tages that they are light, and easily removable; repetitive
machinery units can have integrally molded enclosures made as
part of the cover. Moreover, FRP covers, properly designed and
fabricated, can provide superior resistance to attack by sul-
furic acid.
Aluminum covers for rectangular openings may be custom
fabricated from corrugated sheet aluminum mounted on frames,
forming an arch, thereby permitting access to the space below
through ports at the ends. Alternatively, specially formed
interlocking aluminum sheets may be used to provide a reasonably
airtight flat cover. In this form, the sheets are held in place
at the ends with a gasketed, two piece frame. The cover can be
removed for access to the tank by one man simply by removing the
top half of the frames and rolling the cover up as one would
roll up a rug.
Fabric structures or membrane structures are a relatively
recent development. They offer a means to enclose large amounts
of space (possibly entire treatment plants) with minimal inter-
nal supports. There are basically three types: (1) "single
dome" covers supported by air pressure maintained in the en-
closed space; (2) "double dome" configurations where the struc-
tural members are made of fabric and gain their strength from
air within the member itself; and (3) networks of tension mem-
bers (cables) covered by attached membranes. Classroom build-
ings, convention halls, pavilions, stadiums and recreational
centers have chosen fabric covers because they become increas-
ingly cost effective as a real requirements increase. The
fabric is composed of teflon coated fiberglass with a tensile
strength of up to 1,000 pounds per inch of width. Pressure
regulation of the building, either above or below atmospheric,
is necessary for proper roof shaping, but loss of pressure is
not catastrophic. A fabric roof which utilizes a three-layer
cell with a movable inner,half reflective, half translucent,
membrane has been developed which is capable of minimizing
118
-------
FIGURE 8. FRP COVER FOR RECTANGULAR OPENINGS
119
-------
seasonal heating and cooling loads of the enclosed space even
in severe climatic regions.
Advantages--
General advantages of these unconventional covers and en-
closures over more conventional materials are as follows:
• Lower installed cost than concrete or steel, in
most sizes,
• Extra savings from reduced wall loads,
• Lightweight. Some can be installed in a single
ground-assembled piece by crane or helicopter -
general ease and speed of erection,
• Self-supporting,
• Minimum maintenance.
Special advantages identified for FRP are as follows:
• Good light transmission,
• Non-conductive,
• Thermally insulating,
• Formable to any specialty shape; i.e., outline of
specific place of equipment.
Advantages unique to the aluminum frame covers include:
• Can be assembled by unskilled labor,
• Easily modified when penetration or additional
equipment mounting is required.
Teflon-fiberglass fabric covers have the following unique
advantages:
• Lightest weight roof - 1/3 weight of conventional
truss,
• Rain will clean teflon fabric,
• Good light transmission,
• Can be high or low profile,
• Variety of construction techniques offers wide choice
in methods used to regulate enclosure temperatures.
120
-------
Disadvantages—
Generally, these unconventional covers are:
• More vulnerable to vandalism,
• Load limitations of these materials may limit use
of cover-mounted equipment.
Cost Data—
An installation cost comparison for basic covers based upon
manufacturers information is shown in Table 25. Appurtenances
and specialty requirements for prefabricated covers greatly in-
fluence their cost and each project must be examined individu-
ally. Covers which enclose process units on all sides, have
high thermal insulation values, and transmit some light to the
interior are marketed as "enclosures" and can replace a much
more costly conventional building with its ancillary HVAC and
lighting.
TABLE 25. UNIT COSTS FOR UNCONVENTIONAL COVER MATERIALS
Type
Circular
50 '<()
lOO1*
ISO'*
200'$
FRP
Aluminum
Concrete
Fabrict
FRP
Aluminum
Concrete
Fabric
FRP
Aluminum
Concrete
Fabric
Fabric
Cost, dollars/sf*
11-13
12-14
14-16
16-18
9-11
9-11
10-12
10-12
9-11
8-10
10-12
9-11
8-10
Type
Rectangular
10" span FRP
Concrete
10' span FRP
Concrete
40' span FRP
Concrete
60' span FRP
Concrete
Aluminum spans to 60"
Cost, dollars/sf*
6-11
10-11
7-11
11-12
8-12
—
8-12
-
5-10
* Projected area.
t Teflon-fiberglass air supported.
121
-------
REFERENCES
11. Evaluation of Trenchless Sewer Construction at South
Bethany Beach, EPA-600/2-78-022.
12. Nester, A. W. The American City, February 1974, pp. 45.
13. Nester, A. W. The American City, February 1974, pp. 45.
14. Anon. "Fiberglass Fights 803 Attack on Sewers". Water
and Sewage Works, February 1976.
15. Leggatt, A. J., The Practical Application of Glass
Reinforced Polyester as a Structural Material. Paper
presented at the ASCS Spring Convention, Dallas, Texas.
April 1977.
16. City of Roseville, California Wastewater Treatment Plant.
City of Turlods Wastewater Treatment Plant.
17. Pima County, Arizona; Ina Road Wastewater Treatment
Project.
122
-------
SECTION 7
NOVEL METHODS AND MATERIALS OF CONSTRUCTION
NOVEL METHODS AND MATERIALS
Novel methods and materials are those which represent new
approaches to the task of wastewater conveyance and treatment
facilitation. In this chapter, the methodology for the develop-
ment of novel methods and materials of construction is ex-
plained, as is the rationale behind the areas of concentration
of idea development. Finally, those ideas which were considered
to have potential for cost savings are outlined.
IDEA GENERATION
At the outset of the study it was anticipated that novel
methods and materials would be generated in two principal fash-
ions: external to our company, and internally within the com-
pany. The methods employed and the results of those efforts
are described in succeeding paragraphs. Generally, the objec-
tive was to develop as many external ideas as possible, compare
these to the identified cost centers in Section 5, and generate
ideas internally to resolve any apparent problems with imple-
mentation.
External Idea Development
Contacts were established with representatives of mechani-
cal equipment suppliers, research associations, and wastewater
treatment plant owners and operators. These contacts were then
questioned in regard to novel methods they might have a know-
ledge of. In addition, computer assisted literature search
methods were employed to seek out documented, new approaches.
While many ideas were suggested for the study, the great ma-
jority did not fall into the categories of construction cost
reductive novel methods and materials. The topics most fre-
quently suggested were:
1. Process improvement ideas,
2. New process ideas,
3. Ideas which would reduce O&M costs,
123
-------
4. Mechanical equipment ideas.
Some of these categories (1, 2 and 4) produce indirect
capital cost savings. For example, a process improvement idea
leads to smaller treatment units than would previously have been
required for the same degree of treatment. Some preliminary
development of ideas within categories 1, 2 and 4 was under-
taken, along with the instigation of programs for obtaining fur-
ther ideas within these categories. The principal thrust of the
study effort was to produce new and more cost-effective methods
of wastewater facility construction. We believe these areas of
investigation should be pursued in the future studies of a simi-
lar nature. We therefore offer the following observations of
our sources:
Industry--
We know that many industrial processes involve construction
of facilities that are similar to those used in wastewater sys-
tems, and that industry strives to minimize its construction
costs. Therefore, it follows that an in-depth review of methods
and materials of industrial construction should uncover ideas
which could be effectively applied to wastewater facility con-
struction, thereby reducing costs.
Our efforts to uncover ideas from the industrial sector
were directed toward three principal areas: National associa-
tions of representative wet and liquid processing industries,
industries within the Central California area, and contractors
involved in the construction of both industrial and wastewater
facilities. In general, the associations were of little help
(no replies were received from more than 80 percent of those
contacted). Notable exceptions were the Asphalt Institute, the
Sulfur Institute, and the National Canners Association; all of
whom provided useful input. Contractors indicated that in con-
struction they were not hesitant to cross such technical bound-
aries as exist between wastewater and industrial process tech-
nology; contractors frequently undertake construction in both
fields, and, indeed, in many other construction fields.
Mechanical Equipment Suppliers—
Much of the information offered by mechanical equipment
suppliers centered around mechanical equipment, process improve-
ments and cost reduction. Some ideas were suitable for in-
creased use of state-of-the-art materials and for unconventional
methods, but no truly novel ideas were suggested.
Patent Information—
Preliminary investigations were made to establish the de-
gree of effort necessary to obtain potential ideas from patent
sources. Two volumes of Patent Abstracts for Solid Waste
Management were reviewed; this information yielded no ideas
124
-------
insofar as novel methods and materials of construction are con-
cerned. It was concluded that only patents relating directly to
construction would be valid. A patent search of the size neces-
sary to ensure full subject coverage is greatly beyond the scope
of this project and would, in fact, be best undertaken as a
separate major study.
Foreign Research Associations--
Foreign construction and wastewater treatment associations
were contacted. No information was obtained from the construc-
tion associations. Some of the wastewater treatment associa-
tions offered general information concerning their research
programs (the United Kingdom associations especially), but such
ideas fell inevitably into new process or process improvement
categories, and were dropped from further consideration.
Wastewater Treatment Plant Personnel—
Four wastewater treatment plant managerial and operations
personnel were selected for a telephone survey. It was postu-
lated that their close contact with wastewater treatment plant
construction projects might have led them to develop innovative
ideas. Unfortunately, this was not the case.
Computer Literature Searches—
The lack of success achieved with this method was document-
ed previously in Section 6.
To summarize, very little in the way of cost reductive
novel methods and materials ideas were developed from outside
sources.
Internal Idea Development
Since efforts to develop suitable ideas from various ex-
ternal sources were not successful, the study team decided to
generate ideas from within our own organization. Early attempts
to do so resulted in failure. Most engineers' minds are con-
strained by a myriad of rules, regulations and conventions which
inhibit original thought. When engineers are hired for their
conceptual abilities they are most frequently used in process
development areas, not in design and construction. This does
not imply that design and construction engineers are limited in
conceptual ability; rather, such an engineer's free conceptual
thought is alienated by requirements. This problem has been
identified by others in the past.
It was necessary to develop procedures whereby the con-
straints on the engineering mind could be relaxed, temporarily
at least. The developed solution was to isolate one or two
engineers from outside influences, to take an identified cost
center (such as excavation or vertical wall construction) and to
work from concept through to detailed methods and materials of
125
-------
construction. As soon as any constraint on an engineer's
thought became apparent, the interviewer(s) redirected thought.
All ideas were noted and no judgement on ideas was permitted.
The engineer's train of thought was allowed to flow for both the
individual and group. After development of all trains of
thought, each idea was reviewed in detail and impracticable
ideas were eliminated. The maximum period measured where useful
ideas were generated through free thought was between two and
four hours.
Idea Treatment
Novel ideas were developed through two stages. For each
idea, the methodology of the idea conception and idea develop-
ment was set down, and sufficient work was carried out to es-
tablish that the idea was suitable for potential engineering
applications. Secondly, for a selection of the best ideas,
detailed cost analyses were made, where possible, to establish
that the idea passed the test of capital cost reduction. Ad-
vantages and disadvantages were established, and in one or two
cases the ideas's potential for implementation was discussed
with manufacturers and/or contractors. In some cases, cost data
were not available or special cost studies beyond the scope of
this work would have been necessary; several ideas are identi-
fied where the cost analysis was not performed but which may be
cost-effective in certain applications.
Several of the ideas developed beyond the first stage
failed to meet the criterion of capital cost reduction. These
were rejected, and are listed in Appendix B along with uncon-
ventional ideas rejected on similar grounds. Cost information
was not uniformly available for all ideas; in some cases, only
limited cost data were available covering a narrow range of con-
struction conditions. Accordingly, selection of ideas required
engineering judgement which recognized the cost data limita-
tions. Ideas found suitable for inclusion as novel methods and
materials of construction include:
• Drilled vertical shaft construction
• Reinforced earth tank
• Precast concrete tanks
• Reinforced asphalt pond liner
Other novel ideas which were not tested from a cost stand-
point but which may be worth further study include:
• Shipboard treatment
Deodorizing foul air with botanical systems
126
-------
These two ideas are described in this section with the under-
standing that added work would be needed to determine their
suitability on novel methods as defined
NOVEL IDEAS
Drilled Vertical Shafts
The use of vertical shafts 50 to several hundred meters
deep in the earth for certain wastewater management and treat-
ment applications has been proposed. Economic justification of
the method(s) will rest on costs of constructing shafts of re-
quisite depth and diameter, and comparison with more convention-
al construction on a site-specific basis. The technology of
shaft drilling in rock has advanced significantly over the past
decade; much of the impetus toward improved methods has come
from the mining industries and construction associated with
major water resource development projects. Shaft construction
technology is still developing.
Drilling in unconsolidated overburden is likely to be more
difficult and costly than shafts in rock, especially where the
ground is wet and unstable. Methods described here apply to
rock which is essentially self-supporting. Excessive depths
of overburden will adversely affect the economics of waste
treatment systems that utilize vertical shafts.
Use of deep shafts is proposed as an alternative to con-
ventional shallow surface tankage for:
• Wastewater aeration-biological treatment
• Chlorine contact chambers
r Slvdgc thickening (dissolved air flotation)
• Solids separation (dissolved air flotation)
• Attached growth reactors
Implementation—
A discussion of some of these applications and developments
in deep shaft treatment technology may be found in Appendix B.
Raise drilling is the most economical method for shaft construc-
tion in rock for situations where access required at a given
site is sufficient to offset mobilization and other fixed costs.
In raise drilling, the rotary cutter head is placed at the bot-
tom of the shaft site for starting the bore, and drills upward,
pulled from the surface by the drill pipe which passes through
a small pilot hole. Except for the cutter head, all machinery
(derrick, motor, controls, etc.) are located on top of the
127
-------
ground. Cuttings fall to the bottom of the hole and are removed
by a normal mucking method.
Raise drills, teamed with domed reamers, have excavated
shafts up to 6 meters (20 feet) in diameter and up to 600 meters
(2,000 feet) in depth. Boring rates are highly variable, but
one to five meters per hour may be attained.
Since raise drilling requires access to the bottom of the
shaft before drilling, it is practical only for situations
where rather intensive development of underground facilities is
planned. This could occur, for example, where a number of
shafts are needed at one site, justifying driving of a horizon-
tal drift to connect the bottoms of all shafts. In any event,
the first shaft at a site will have to be drilled blind from the
top down. Where deep tunnels are used for sewage conveyance,
the necessary drop shafts can be raise drilled.
Blind drilling of large diameter (e.g., 1 meter (40 inches)
to 2.5 meters (8.3 feet)) holes is similar to the rotary well
drilling process using reverse circulation. Air or water can be
used as the medium for bringing cuttings to the ground surface.
The cuttings flow upward through the double-wall drill pipe. No
slurry or drilling mud is used. The size of the diameter that
can be blind-drilled is limited by the ability to force cuttings
to flow from the perimeter of the hole to the center where they
enter the upward flow within the drill pipe. Without further
technical advances, the maximum feasible diameter will remain
at about 2.5 meters (8.3 feet).
The blind-shaft borer is a new concept currently being de-
veloped by the Bureau of Mines (Department of Interior) for
boring extremely large and deep holes from the top down. A
machine, now being built for testing early in 1978, is designed
to bore holes up to 7.5 meters (25 feet) in diameter. It is ex-
pected to be economical only where shafts of 300 meters (1,000
feet) depth or greater are required. The blind-shaft borer
functions essentially the same as a tunnel boring machine placed
vertically, and totally different than the drill techniques pre-
viously described. The machine itself, including operator, sits
in the bottom of the shaft and has a mechanical system for re-
moving cuttings. There are no elements at ground surface, ex-
cept for muck handling. The mucking system includes scrapers at
the bottom of the hole, conveyors, and bucket elevators to the
top of the machine, where cuttings are dumped into skips that
haul them to the surface.
Cost Considerations—
The cost of deep shaft construction depends on several fac-
tors, and can be expected to vary considerably. The following
assumptions were employed for the purpose of developing the
costs presented in Table 26.
128
-------
TABLE 26. GENERAL COST RANGES FOR DEEP SHAFTS*
Average depth
Meters
2.5m
diameter
1 m
diameter
(8.2 feet)
drilled shaft
60
120
200
(3.3 feet)
drilled shaft
110
240
400
Feet
200
400
650
350
800
1,300
Cost range
$ per meter
910-6,700
860-5,900
840-5,500
405-1,150
375-870
365-800
S per foot
260-2,040
245-1,800
235-1,680
115-350
105-265
105-240
* Costs in 1978 dollars.
• Holes are drilled in competent rock of medium
strength (10 to 25 ksi compressive strength).
• Each shaft is lined with a steel casing,
grouted in place.
• Drill is fully utilized on a two-shifts per day
annual basis (95 percent or greater utilization).
• Site preparation for drilling is included, but
disposal of spoil material is not.
The cost of raise-drilling is estimated to be in the range
of 60 to 75 percent of the cost of blind down-drilling for com-
parable shaft diameters and depths. Raise-drilling can provide
much larger holes than blind-drilling, up to 6 meters or more in
diameter. However, because of the required underground access,
raise-drilling is likely to be feasible only on larger projects
which require tunnels for other purposes that could incidentally
provide access for the raise drill.
In order to fully utilize a drill, and thus minimize fixed
charges and amortization on a unit meter basis, it may be cost-
effective for EPA to own the equipment and lease it to contrac-
tors. Full utilization of a blind drill capable of making 2.5
meters (8.3 feet) diameter holes would produce a total of about
1,200 meters (4,000 feet) of vertical shaft per year in average
strength rock. This figure includes allowances for short moves
within a site, and non-productive time allowances. Long moves
129
-------
would have to be made on weekends or would result in curtailed
annual production totals.
Reinforced Earth Tank
This concept was developed as a possible solution to the
high cost of conventional vertical wall construction for sedi-
mentation, equalization, aeration, and similar excavated tanks.
Functionally such walls were determined to be watertight and to
resist internal and external liquid pressures, and external
earth loadings.
Consideration centered on how to eliminate the external
forces. Groundwater pressure could be eliminated by drainage.
Earth forces could be eliminated if the earth itself is rein-
forced. The use of a "reinforced earth" method was indicated,
which, if used in conjunction with a waterproofing agent, would
provide a vertical, waterproof wall capable of resisting in-
ternal water pressure.
Implementation—
Reinforced earth is a patented construction method in this
country; as such items used in this type of construction are
obtained through a sole source, the Reinforced Earth Company.
This method has been used by the Highway Department in the State
of Washington. Reinforced earth is a composite material formed
by the association of non-cohesive soil and reinforcements tied
together by facing plates, which form the visible wall. The
basic mechanism of reinforced earth is the action of friction
between the soil and reinforcements; the active horizontal com-
ponent of soil pressure being absorbed by the reinforcements.
Reinforcements are normally thin strips of galvanized
steel or aluminum. These strips are fastened to interlocking
precast panels or semi-elliptical steel skin facing panels.
The soil should have a minimum angle of friction of 25 degrees,
with not more than 15 percent passing a 200 sieve.
The first step in construction is to install an under-
drainage system. The reinforced earth wall is constructed by
setting lifts of facing panels on an unreinforced concrete
footing. Non-cohesive soil is spread and compacted and the
rows of reinforcements are laid horizontally and bolted to the
facing panels. This process is then repeated until the struc-
ture is complete. The structure is stable at all times during
construction.
A section of the wall proposed for use in vertical wall
construction and a typical reinforced concrete tank wall sec-
tion are shown in Figure 9. Regular details for pipe penetra-
tions, machinery fixings and sludge hoppers are also shown.
130
-------
« v ,--,-», • —Tfi
VGRANULAR FILL -^-~
REINFORCING STRIPS
-------
Cost Considerations—
Where suitable native soil material is available and where
groundwater can be maintained at a level below the reinforced
earth mass, the cost of reinforced earth walls for process units
is estimated to range from $130/m2 ($12/ft2) for a 3m (10 foot)
high wall to $170/m2 ($16/ft2) for a 12m (40 foot) high wall.
This cost includes foam board facing and a hypalon liner. Credit
is given to the reinforced earth design for a simpler base slab
construction. Analysis indicated reinforced concrete construc-
tion to be approximately 25 percent cheaper using a 3m (10 ft)
high wall. For a 12m (40 ft) high wall, reinforced earth was
approximately 30 percent cheaper than reinforced concrete.
Reinforced earth becomes more economical than reinforced con-
crete at about the 6m (20 ft) wall height. If soil must be im-
ported in order to be suitable for the reinforced earth design,
then only walls 8m (26 ft) and above are more economical in re-
inforced earth.
Advantages—
An advantage of reinforced earth over conventional rein-
forced concrete is its lower capital cost for walls greater than
6m (20 ft) high at locations where non-cohesive material is
available, and groundwater levels can be maintained naturally,
or artificially, below reinforced earth massformation. Also,
where tankage is to be constructed on unstable soils of con-
siderable depth, the reinforced earth concept is lower in cost
than pile supported structures for all wall heights.
Disadvantages—
The major disadvantage is the loss of the reinforced earth
area around the tank for future use, unless the reinforced earth
wall is removed. For a 12m (40 ft) deep tank this would involve
a strip 9.5m (32 ft) wide. This disadvantage is partially com-
pensated for by the fact that the reinforced earth materials
can be reclaimed and reused. Thus, during an in-plant expansion
project this would mean that an existing tank would be out of
service during construction of a new or larger tank.
A second limitation is the requirement that groundwater
levels be maintained below the reinforced earth structure found-
ation.
Precast Concrete Tanks
The economics and quality of factory precast concrete ele-
ments is known to be superior to cast-in-place concrete work.
Trickling filter structures have been constructed using precast
panel and post-tensioning construction techniques.
Sludge digestion tanks are frequently post-tensioned after
erection of the concrete shell. It would appear that there
should be no reason why all treatment units should not be con-
structed from precast panels.
132
-------
Potential cost savings resulting from precast versus cast-
in-place construction increase with tank height. Cost savings
are in the 0 to 5 percent range for relatively low tanks (up to
5 meters or 17 feet high), 5 to 15 percent for medium height
tanks (5m-19m or 17-30 feet)and 15 to 25 percent for higher
tanks. Tanks higher than 9 meters (30 feet) would normally
employ post-tensioning in either construction approach. Poten-
tial savings for higher tanks reflect the difference between
casting a high wall versus erection of precast tilt up panels.
Implementation--
Circular tanks can be constructed using a series of
straight wall segments. Each segment is poured with curved
post-tensioning conduits cast-in-place. Following completion
of a cast-in-place slab, each segment is erected, the spaces
between units grouted, and post-tensioning tendons are pulled
through the conduits. Each tendon is then post-tensioned to
the required force and the conduit grouted under pressure.
Rectangular tanks would be constructed with both vertical
and horizontal conduits. The cast-in-place base is poured with
threaded sockets into which high tensile bars are later thread-
ed. The precast units are threaded into the bars, the spaces
between units grouted, and horizontal tendons installed. Post-
tensioning of both horizontal and vertical steel is then carried
out.
Reinforced Asphalt Pond Liner
Where potential for leakage from an earthen basin used for
sewage or sludge exists, providing an impervious layer over the
basin area would be a high cost. Where the use of a soil addi-
tive (e.g., betonite) is not considered adequate, or suitable,
the use of sprayed liquid asphalt is recommended as being eco-
nomical. Unfortunately, the resulting layer has disadvantages:
it is brittle, subject to fracture under thermal variations, and
easily damaged by maintenance operations. Typically it has,
therefore, been covered with a 300 mm (12 inches) layer of soil.
In considering this cost center and evaluating alternatives to
asphalt, the investigation also centered on methods whereby
asphalt might be reinforced cheaply to form a suitable coating.
Discussion with the Asphalt Institute revealed the fact that
porous concrete bridge decks are waterproofed utilizing asphalt
reinforced by "Petromat"; a random, non-woven polypropylene
fabric. Use of this fabric, together with asphalt, as a pond
liner was judged potentially cost-effective. Further thought
led to the concept of using a liquid asphalt/chopped glass fiber
matrix sprayed simultaneously onto a prepared (sand) surface to
produce a similar reinforced asphalt matrix. The basis for such
a system comes from the "Monoform" roofing system owned by
Flintkote.
133
-------
Implementation--
Construction of the reinforced asphalt pond liner would
involve subgrade preparation, installation of a granular base
course and application of two coats of reinforced asphalt liner.
Subgrade preparation includes necessary pond excavation and
embankment fill adequately compacted. Large rocks would be re-
moved from the surface layer. 100 to 150 mm (4 to 6 inches) of
sand material would be laid and compacted as a base for the
liner. The line installation would require a liquid asphalt
tank truck, and a second vehicle to carry the chopped glass
fiber and spray arm. The two vehicles would work in tandem.
The spray arm would probably have a number of spray guns similar
to those in present day use for roofing application. These guns
have an individual capacity of 2,300 m2 (25,000 ft2 or approxi-
mately 0.6 acre). Ten would be required to cover six acres. If
controlled feed to so many guns became difficult, a larger gun
could, no doubt, be developed.
Application rates to achieve 3 mm (1/8 inch) layers, with
a total of 6 mm (1/4 inch) are attainable. This thickness of
coating on the granular base course should provide a waterproof
coating, with good resistance to routine maintenance and long
life.
Cost Considerations--
Costs of equivalent conventional methods of pond water-
proofing liners range from $5.00 to $8.50 per m2 ($4-7/yd2).
The cost of the proposed method is estimated by Flintkote to be
within the range $1.70 to $2.40/m2 ($1.42 to $2.0/yd2). This
assumes the use of tankers and manually operated guns. Allowing
the cost of granular bedding, the total cost for this construc-
tion is in the range of $3 to $3.60/m2 ($2.50 to $3.00/yd2).
Advantages—
The advantages of a reinforced asphalt pond liner lie be-
yond the low first cost. Repair and patching of the membrane
is extremely simple. The asphalt emulsion and glass cloth are
the only materials needed. Resistance to domestic wastewater
is excellent, and resistance to foot and even some vehicular
traffic is achieved.
Disadvantages—
The material would only be capable of absorbing limited
differential settlement, and will become increasingly less
flexible with time. This particular disadvantage is offset to
some degree by the fact that most differential settlement will
occur during the early life of the pond. The poor resistance
of reinforced asphalt to localized or point loading is also a
disadvantage. In common with most liners, weed inhibitors and
rodent control precautions must be taken.
134
-------
Recommendations—
In view of the limited potential market and the uncertainty
of whether or not this method of pond lining would be accepted
by engineers and regulatory agencies, it is possible that no
manufacturer would be interested in developing the equipment
necessary for full scale application. It is recommended, there-
fore, that a demonstration project using existing roof coating
methods and equipment be undertaken on a 1-2 ha (2.5 to 5 acre)
lagoon. Application techniques, application costs and perform-
ance should be closely monitored, and, if the project is suc-
cessful, manufacturers should be made aware of it so the poten-
tial market can be developed.
OTHER NOVEL IDEAS FOR FURTHER STUDY
Two novel ideas have been identified which require addi-
tional information to determine their potential as cost-
effective solutions. These include shipboard treatment and de-
odorization of foul air with botanical systems. Potential ap-
plication of these approaches are considered limited but worth
mentioning here.
Shipboard Treatment
In seacoast cities and cities located near major waterways,
existing separate and combined wastewater interception systems
and storm sewers follow the contour of the land to discharge
points, which are near to or in deep water. As a rule, the task
of accommodating increased wastewater flow involves construction
of new interceptor systems through already congested urban areas
to locations where suitable treatment works can be constructed.
In order to expedite dry weather flow and supplement storm sea-
son flow provisions, a possible alternative is modifying obso-
lete or surplus marine vessels into wastewater treatment facili-
ties.
The vessels could be stripped of the equipment required for
going to sea, and re-equipped in drydock where skills required
for construction of wastewater treatment systems are readily
available. The vessels could then be towed to their final
position for connection to shore-bound collection systems or
combined sewer overflows. The on-board treatment systems could
be arranged for treatment of overflow volumes to remove pollut-
ants and provide necessary disinfection. Solids removed from
the wastewater would be stored until storm flows subside, then
returned to the on-shore interceptor for conveyance to shore-
based treatment facilities.
A similar concept could be employed where a vessel is used
as a treatment system for an overloaded collection system. This
135
-------
approach would eliminate the need for providing solids stabili-
zation processes on the vessel, and reduce overall costs of
operation.
Implementation—
Existing vessels held in reserve, or for salvage, would be
required in order to implement this idea. For example, Liberty
ships in Navy mothball fleets could be used for this purpose.
However, a survey of this potential source showed that as of
the end of March 1978, only seven Liberty ships remained in the
reserve fleet. Of this number, four are located on the James
River (Virginia) and three are berthed in Suisun Bay California.
Four were scheduled to be scrapped, one is to be used as a
museum and two were reserved for use for classified Navy pro-
jects. Thus, it would appear that this particular source could
not be tapped for this purpose. The approach could be employed,
however, using other types of marine vessels; such as smaller
tankers made obsolete by the super tankers now favored by ship-
ping companies. Vessels of this type, because of their large
holds, would make ideal platforms for construction of process
tankage. In large cities where treatment sites are a premium
the use of such floating platforms could be cost-effective and
less of an aesthetic intrusion to the waterfront if the treat-
ment facility was disguised within the interior of the vessel.
Existing vessels would require modification to provide the
required treatment capacity. Scrap value would have to be low
relative to alternative site costs. Maximum utilization of
existing equipment and space would have to be made to further
reduce costs. Examples of modifications and use of existing
features include:
• Existing equipment (such as hydraulic and electric
systems) could be integrated into the plant design.
• Large holds could be converted into process tanks.
• Existing boiler water laboratories could be refitted
as water quality laboratories.
• Crew living and messing quarters could be refur-
bished for plant operators.
In the case of ships of a single design, a single treatment
plant design could be developed and used for several plants; the
plants could then be produced at shipyards similar to the con-
cept employed for construction of a class of ships. Other ad-
vantages to this arrangement would be centralized testing and
quality assurance, enabling a completed plant to be delivered
to the user.
136
-------
A pier would have to be provided by the user for docking
the floating plant. Shore supporting connections, such as
electric power and water, would be required. Additionally, con-
nection to the sewerage system,and pumping and sludge removal
would be required.
No known changes to regulations, codes, etc. would be re-
quired to implement this idea. However, some institutional
barriers may be encountered in obtaining existing vessels. For
example, at the time of writing (prior to issuance of 95-217)
it is unlikely that EPA regulations would permit the adoption
of such a project.
Cost Considerations—
Cost savings would be dependent on initial cost for the
vessels and the extensiveness of the modifications required, as
well as site specific conditions for land construction. Al-
though building floating plants from the platform up would
probably not be competitive, this technique has been used by
Ishikawajima-Harima Heavy Industries Co. (IHI) of Tokyo to
manufacture a 750 metric ton/day pulp plant for a remote loca-
tion in Brazil. IHI claims that construction costs were 15 to
30 percent less than for field fabrication.
Advantages—
Shipboard treatment plants could be located in protected
areas along seacoasts or same inland waterways. They would be
particularly attractive in areas where poor soil conditions
would make conventional construction difficult and expensive.
Advantages derived from shipboard treatment works include:
• Potential significant reduction or elimination of
land requirements.
* Enhanced salvage value and resale possibilities.
• Flexibility through modular construction.
* Potential use as interim measure or for facilities
expansion.
• Protection from vandalism.
* Built-in flood protection.
• Potential for multipurpose use of shipboard
facilities not required for treatment capacity.
Disadvantages—
Floating wastewater treatment plants could not be located
in landlocked areas or on non-navigable streams. In addition,
137
-------
certain conditions along seacoasts or inland waterways may pre
elude implementation of this idea. These include areas where
breakwaters are required to provide reasonable quiescence,
where extreme tidal variations occur, and where sufficiently
acceptable, inexpensive land is available. There would also be
plant size limitations; the number of modular units required
could make this concept realistic. Influent pumping stations
would be required.
Deodorizing Foul Air with Botanical Systems
Objectionable odors from wastewater interceptors and waste-
water pumping and treatment facilities are sometimes removed by
mechanical or biological scrubbing systems. These systems are
ordinarily constructed using conventional materials of construc-
tion (e.g., plastic media and steel tanks). A simpler system
might provide cost savings. Because foul air frequently con-
tains carbon dioxide at concentrations greatly in excess of
the atmosphere, the use of botanical systems (i.e., growing
plants in greenhouses) is an attractive concept which might
reduce construction costs as well as put the foul air to a
beneficial use.
Greenhouse structures are sometimes used to protect sludge
drying beds from rain. It is possible that foul air might be
routed to such areas and use be made of drying sludge for grow-
ing botanical systems.
A botanical deodorizing system would consist of a green-
house containing appropriately selected plants. Foul air would
be delivered to the greenhouse to provide a carbon dioxide en-
riched atmosphere for accelerated plant growth. Potential odor
reduction mechanisms include absorption on leave surfaces and
oxidation of odor producing compounds in the oxygen rich atmo-
sphere surrounding continuously lighted vegetation. Plant
growth accelerated by the unique greenhouse conditions with its
carbon dioxide source and sludge fertilized soil could produce
soluble plants or cuttings. An experimental system of this kind
near Willitts,California,produced grape cuttings as a by-product.
Off gases from a small trickling filter were captured and vented
into a small greenhouse in this particular case. Oxygen enrich-
ment of the atmosphere and the masking effect of pleasant plant
odors would also help to decrease the offensiveness of the gas
released from the greenhouse.
Implementation—
In order to implement this idea, design criteria would need
to be established and appropriate plants would need to be se-
lected. Determination of such things as growth-limiting fac-
tors, growth rates, supplemental lighting requirements, oxygen
production rates, and areal requirements must be established to
determine actual feasibility. Design and construction of
138
-------
greenhouses is ordinarily carried out according to well-
established principles, and only minor design changes would be
required to efficiently distribute the foul air and to collect
the deodorized air for release. Consideration should be given
to a cascade arrangement of greenhouses to reduce the potential
for inadvertent release of odors due to incomplete reaction.
The system for delivering the foul air from its source to the
greenhouse would be the same as for any other deodorizing
system.
Because the plants grown in the greenhouses potentially
have a marketable value, consideration should be given to har-
vesting and marketing requirements. This effort may be impor-
tant in offsetting the total costs of the botanical system.
There are no known regulations or codes which would require
change to implement this concept.
Cost Considerations—
Information on the potential savings in using botanical
deodorizing systems are not available. Greenhouse construction
would be cheaper than scrubbing systems due to its simplicity
and lower use of steel. Economics would depend heavily upon
the areal requirements for the greenhouses. It is possible
that this concept would be appropriate only at locations where
greenhouses already exist.
Advantages—
Botanical systems could be used in areas where the climate
is relatively mild and solar radiation is reasonably consistent
throughout the year. The major advantage of botanical deodoriz-
ing systems would be the potential reduction in material and
construction costs due to its simplicity. An additional benefit
would be harvesting of a marketable by-product which would put
the foul air to a beneficial use and would reduce overall costs.
Public relations aspects of such a "natural" system are probably
quite positive since the idea is in harmony with many of the
views expressed by ecologists and other concerned citizens.
Disadvantages—.
Botanical systems would be inappropriate in areas where
climatological conditions are unsuitable or would be expensive
to overcome; e.g., where excessive insulation and supplemental
light would be required. Also, the distance of the foul air
source to the greenhouse site, and the availability and cost
of land would be factors affecting the economics of botanical
systems.
139
-------
APPENDIX A
CONSTRUCTION COST SUMMARIES
The following cost breakdowns were developed to help locate
high cost centers in terms of labor, material, or area of the
completed unit process.
The breakdowns were derived by taking examples from real
projects, breaking them down to unit quantities, and pricing
the quantities. The mechanical equipment, structural style,
site conditions, and labor market are among factors which will
vary project costs from one project to the next. However, costs
for each construction category are expected to represent ap-
proximately the same percentage of the total cost.
140
-------
TABLE A-l.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Influent Pump Station
Item
Earthwork
Foundation base slab
Ground floor and
roof slab
Discharge structure
Vertical walls
Precast architec-
tural face panels
Misc. structural
Variable speed pumps
Other mechanical
equipment
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
480
1,529
484
6,320
-
-
-
-
8,813
5.3
2.0
Labor
-
4,032
3,146
4,073
19,280
-
-
-
-
30,531
18.3
6.9
Concrete
Mate-
rial
-
13,230
3,528
13,363
13,312
12,750
8,528
-
-
64,711
38.6
14.7
Labor
-
1,029
4,410
1,039
10,140
2,250
15,839
-
-
34,707
20.7
7.9
Rebar
steel
-
3,058
8,996
3,089
13,600
-
-
-
-
28,743
17.1
6.5
Cost
dollars
35,948
21,829
21,609
22,050
62,652
15,000
24,367
75,000
161,800
440,255
1167,507
100
38. 0
Cost
% of
struc-
tural
concrete
-
13.0
12.9
13.2
37.4
9.0
14.5
-
-
100
Cost
% of
total
8.3
4.9
4.9
5.0
14.3
3.4
5.5
17.0
36.7
100
ADDENDUM - TABLE A-l
1. Deep structures require the extra weight of additional
structural concrete to overcome bouyance forces, therefore,
floor and wall costs per square foot are higher than for
other structural types.
2. Mechanical equipment comprises 53.7 percent of the pump
station cost. The "typical" real station examined had
twelve separate mechanical systems.
141
-------
TABLE A-2. CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Preliminary Treatment
Item
Earthwork
Horizontal slabs
Vertical surfaces
Misc. structural
Grit collection
equipment
Grit washers
Flume + recorder +
housing
Gates
Misc. mechanical
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
292
2,528
175
-
-
-
-
-
2,995
10.0
2.5
Labor
-
1,452
7,200
954
-
-
-
-
-
9,606
32.1
7.3
Concrete
Mate-
rial
-
2,309
2,336
1,442
-
-
-
-
-
6,087
20.3
5.1
Labor
-
536
3,680
824
-
-
-
-
-
5,040
16.8
4.2
Rebar
steel
-
2,639
2,688
605
-
-
-
-
-
5,932
19.8
5'. 0
Cost
dollars
11,008
7,228
18,432
4,000
42,500
22,000
10,200
2,000
1,500
119,268
Z29,660
100
24.9
Cost
% of
struc-
tural
concrete
-
24.1
61.5
13.4
-
-
-
-
-
100
Cost
% of
total
9.2
6.1
15.5
3.4
35.6
18.4
8.6
1.7
1.3
100
142
-------
TABLE A-3.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Rectangular
Primary Sedimentation Tanks
Item
Earthwork
Tank floor slabs
Tank solids hoppers
Vertical walls
Tank piers
Ground level cross
beams
Ground level flat
slabs
Misc. structural
Pumping equipment
Sludge collection
equipment
Misc. mechanical
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
500
4,218
15,720
396
810
934
342
-
-
-
22,578
8.2
3.8
Labor
-
3,094
11,418
46,428
2,330
2,814
2,034
1,000
-
-
-
68,118
24.7
11.6
Concrete
Mate-
rial
-
30,114
4,162
13,864
208
2,046
2,148
1,431
-
-
-
52,542
19.0
9.0
Labor
-
27,696
3,666
22,784
1,075
4,850
1,709
1,317
-
-
-
57,820
20.9
9.9
Rebar
steel
-
33,948
6,128
21,294
5,556
6,958
1,236
-
-
-
-
75,120
27.2
12.8
Cost
dollars
21,910
95,352
29,592
120,090
9,565
17,478
8,061
4,090
33,420
175,000
79,200
586,958
£276,178
100
47.1
Cost
% of
struc-
tural
concrete
-
34.5
10.7
43.5
3.5
6.3
2.9
1.5
-
-
-
100
Cost
% of
total
3.7
16.2
5.0
20.5
1.6
3.0
1.4
.7
5.7
29.8
13.5
100
ADDENDUM - TABLE A-3
1. Concrete finishing of vertical surfaces comprises 80 per-
cent of the vertical concrete labor costs if "whip" sand
blasting, fin grinding and sack finishing of tank interiors
is specified.
2. Equipment and piping costs are about equal to the tank
structural construction costs.
3. The sludge and scum collection systems comprise 60 percent
of the total installed equipment cost, the effluent launders
account for 10 percent, the gallery piping 8 percent, and
the scum pumps and sludge pumps each account for 5.5 percent
143
-------
of the total. The sludge and scum collection systems carry
both a high initial cost and a fairly labor intensive in-
stallation sequence, which presupposes difficult alignment
problems associated with a great number of preplaced con-
crete anchor bolts. Flight storage and preservation is
difficult, and wastage and rejection of untrue flights is
often high.
4. In the lower or base structural slabs the material costs,
concrete and reinforcing steel, exceed the formwork and
concrete placing labor costs. Good vibratory concrete
placement and trowel finishing minimize subsequent need for
concrete surface finishing; and formwork is a minimum on
flat surfaces. Fully engineered slab design using minimal
material is required to achieve cost reductions in flat
slabs.
5. The total installed cost for the base structural slab of the
rectangular tanks is nearly double the cost of equal capaci-
ty circular tank base slabs. This is because base thickness
and reinforcing steel must be designed to take cantilever
loads from the walls. This loading may be taken in either
direction in a tank system when adjacent tanks may be al-
ternately dewatered.
6. Central tank piers (necessary for solids collection equip-
ment) require additional slab strengthening. These piers in
turn are often complex in shape, in that they have fillet
bases and "T" tops with the tank cross beams.
7. Sloping wells (sludge collection, grit collection) are ex-
pensive to form because window or shutter top forms are
necessary. Form labor is approximately 6 times as great,
and concrete placing labor 2.5 times as great as for pouring
a comparably reinforced flat structural slab. Precast con-
struction of any slab over 20 degrees inclination is worth
examining as well as minimizing area of tank used for deep
sloping hoppers.
144
-------
TABLE A-4.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Activated
Sludge with Blower Building
Item
Earthwork
Tank base slab
Channel horizontal
slabs
Vertical tank walls
Y-walls
Circular piers
Cross beams
Blower bldg. footing
Blower bldg. floor
and pipe chase
slabs
Blower bldg.
vertical walls
Blower bldg. roof
Misc. structural
and architectural
Handrails and
misc. metal
Blowers
Air diffusion
hardware
Misc. mechanical
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
1,924
854
22,066
18,957
869
4,050
96
954
4,868
1,365
-
-
-
_
-
56,003
11.0
5.6
Labor
-
12,033
4,620
61,389
40,379
1,206
7,200
280
1,988
13,865
2,520
-
-
-
-
-
145,480
28.5
14.5
Concrete
Mate-
rial
-
39,690
5,280
36,211
7,163
527
2,970
960
2,067
4,498
5,865
19,760
-
-
-
-
124,991
24.5
12.4
Labor
-
7,088
825
34,231
3,333
783
4,293
200
504
6,157
1,659
9,280
-
-
-
-
73,358
14.4
7.3
Rebar
steel
-
41,580
5,280
41,021
8,114
945
4,307
520
2,544
5,176
1,092
-
-
-
-
-
110,579
21.7
11.0
Cost
dollars
118,384
102,315
16,859
194,918
82,951
4,330
22,820
2,056
8,057
34,564
12,501
29,040
68,058
171,000
105,000
30,400
1,004,253
£510,411
100
50.8
Cost
% of
struc-
tural
concrete
-
20.0
3.3
38.2
16.3
.8
4.5
.4
1.6
6.8
2.4
5.7
13.3
-
-
-
100
Cost
% of
total
11.8
10.2
1.7
19.4
8.3
.4
2.3
.2
.8
3.4
1.2
2.9
6.8
17.0
10.5
3.0
100
ADDENDUM - TABLE A-4
1. Concrete finishing of vertical surfaces comprises 60 percent
of concrete labor costs for the activated sludge structures.
145
-------
2. On the examined "typical" activated sludge unit the by-
pass, influent and effluent channels, were cast integral
to the wall sections, cantilevered out from the wall.
This required additional wall thickness.
3. Vertical walls and walls with Y-wall top sections are the
highest cost center. Where feasible, tilt-up construction
should be employed for activated sludge tank construction.
146
-------
TABLE A-5.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 ragd) Circular
Secondary Clarifiers
Item
Earthwork
Tank bas« slab
Vertical wall section
Y-wall-s
Tank top beams and
ground slabs
Influent and efflu-
ent encasement
Sludge collection
box
Misc. structural
Tank hydraulic dis-
tribution equipment
Pumping equipment
Other mechanical
equipment
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
458
7,292
6,516
882
672
888
-
-
-
-
1-6,708
9.8
3.9"
Labor
-
2,280
23,290
11,006
1,926
1,326
2,404
-
-
-
-
42,232
24.9
9.8
Concrete
Mate-
rial
-
15,430
7,548
2,408
2,034
3,672
876
3,546
-
-
-
35,532
20.9
8.3
Labor
-
16,928
8,517
4,886
2,502
1,392
572
722
-
-
-
35,519
20.9
8.3
Rebar
steel
-
16,134
11,164
8,124
1,209
1,842
1,291
-
-
-
-
39,764
23.4
9.2
Cost
dollars
21,910
51,230
57,811
32,940
8,553
8,904
6,031
4,286
154,000
33,420
51,200
430,285
£ 169,755
100
39.5
Cost
% of
struc-
tural
concrete
-
30.2
34.1
19.4
5.0
5.2
3.6
2.5
-
-
-
100
Cost
% of
total
5.0
11.9
13.4
7.7
2.0
2.1
1.4
1.0
35.8
7.8
11.9
100
ADDENDUM - TABLE A-5
1. For a circular sedimentation tank, equipment costs are
approximately 10 percent greater than structural con-
struction costs.
2. Center pier influent well, sludge collection drive, ac-
cess bridges, and effluent rim weirs all purchased from
a common supplier account for 65 percent of installed
equipment cost on a circular clarifier. Since items are
factory built, field savings possible are quite minimal.
147
-------
TABLE A-6.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Chlorine Disinfection
Including Chlorination Building
Item
Earthwork
Tank base slab
Tank walls
Chlorine building
base slab
Chlorine building
walls precast
Chlorine building
wall footings
Concrete fill metal
roof with
waterproofing
Chlorine channel
influent/ efflu-
ent structures
Steel frame of
building
Architectural
hardware
Chlorinators ,
evaporators,
injectors
HVAC
Other mechanical
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
321
3,089
28
-
77
1,200
816
-
-
—
-
-
5,031
8.1
3.1
Labor
-
1,597
8,593
28
-
210
1,080
868
-
-
_
-
-
12,376
20.0
7.8
Concrete
Mate-
rial
-
3,696
4,316
648
13,875
356
1,776
436
-
-
_
-
-
25,103
40.6
15.8
Labor
-
858
4,673
1,848
1,688
151
840
100
-
-
_
-
-
10,158
16.4
6.4
Rebar
steel
-
3,828
4,435
324
-
75
108
448
-
-
.
-
-
9,218
14.9
5.8
Cost
dollars
18,964
10,300
25,106
2,876
15,563
869
5,004
2,168
6,600
3,200
31,600
15,000
22,300
159,010
E 61,886
100
38.9
Cost
% of
struc-
tural
concrete
-
16.6
40.6
4.6
25.1
1.4
8.1
3.5
-
-
.
-
-
100
Cost
% of
total
11.9
6.5
15.8
1.8
9.8
.5
3.1
1.4
4.1
2.0
19.5
9.4
14.0
100
148
-------
TABLE A-7.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Gravity Thickener
Item
Earthwork
Tank floor slab-
sloped
Horizontal slabs
surface level
Vertical tank walls
Y-walls
Center influent pier
and influent/
effluent encasement
Sludge collection
well
FRP cover
Foul air ducting
Tank mixer
Misc. mechanical
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
182
138
2,481
2,365
820
167
-
-
-
-
6,153
11.6
3.5
Labor
-
1,093
686
7,924
9,550
474
451
-
-
-
-
20,178
38.0
11.5
Concrete
Mate-
rial
-
2,926
2,218
2,568
1,878
385
164
-
-
-
-
10,639
20.0
6.1
Labor
-
926
515
589
822
275
71
-
-
-
-
3,198
6.0
1.8
Rebar
steel
-
3,800
3,168
3,299
2,140
403
120
-
-
-
-
12,930
24.4
7.4
Cost
dollars
16,627
8,927
6,725
16,861
16,755
2,857
973
23,561
8,800
61,000
12,535
175,621
Z 53,098
100
30.2
Cost
% of
struc-
tural
concrete
-
16.8
12.7
31.8
31.6
5.4
1.8
-
-
-
-
100
Cost
% of
total
9.5
5.1
3.8
9.6
9.5
1.6
.6
13.4
5.0
34.7
7.1
100
ADDENDUM - TABLE A-7
1. Conical sloped floor slabs require 35 percent more concrete
labor manhours, and 50 percent more edge forming materials
and labor manhours than flat structural slabs.
2. Vertical and Y-walls costs comprise 63 percent of the con-
crete construction cost.
149
-------
TABLE A-8.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd)
Sludge Pumping Equipment
Item
Sludge pumping
equipment
Formwork
Mate-
rial
—
Labor
—
Concrete
Mate-
rial
—
Labor
—
Rebar
steel
~"
Cost
dollars
37,000
Cost
% of
struc-
tural
concrete
"
Cost
% of
total
100
150
-------
TABLE A-9. CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Twin Primary Digesters
and Sludge Control Building
Item
Earthwork
Tank floor slabs
Tank vertical walls
Control building
base slab
Control building
floors and roof
Control building
vertical walls
Architectural-tank
and building
Misc. structural
Floor gas holder
covers
Heat exchangers
Gas mixing
equipment
Sludge circulation
equipment
Control building
piping
Misc. mechanical
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
582
15,258
141
533
4,772
690
-
_
-
-
-
-
-
21,976
9.4
2.6
Labor
-
3,642
50,894
697
1,110
13,278
2,010
1,690
_
-
-
-
-
-
73,321
31.5
8.6
Concrete
Mate-
rial
-
8,183
14,754
2,509
1,080
6,670
17,683
910
-
-
-
-
-
-
51,789
22.2
6.1
Labor
-
2,195
3,148
582
282
10,530
19,640
-
-
-
-
-
-
-
36,377
15.6
4.3
Rebar
steel
-
5,355
28,338
3,584
1,980
7,147
3,100
-
-
-
-
-
-
-
49,504
21.2
5.8
Cost
dollars
30,165
19,957
112,392
7,513
4,985
42,397
43,123
2,600
220,000
108,000
54,000
46,000
151,000
11,500
853,632
1232,967
100
27.3
Cost
% of
struc-
tural
concrete
-
8.6
48.2
3.2
2.1
18.2
18.5
1.1
-
-
-
-
-
-
100
Cost
% of
total
3.5
2.3
13.2
.9
.6
5.0
5.1
.3
25.8
12.7
6.3
5.4
17.7
1.3
100
ADDENDUM - TABLE A-9
1. Of the total construction plus equipment cost, the largest
individual cost items are floating covers - 31.3 percent,
digester wall construction - 16.0 percent, and heat ex-
changers - 15.4 percent.
151
-------
2. Of the total construction plus equipment cost, looking at
types of labor, material or equipment, we see that mechani-
cal equipment with its associated controls contributes 63
percent of the total cost, and the next highest being con-
struction formwork labor contributing 10 percent.
3. Construction formwork related costs exceed construction
material related costs for these circular structures.
4. For mechancial equipment the following cost order exists:
Floating covers, heat exchangers, gas compression and
mixing and flaring equipment, sludge circulation pumps, etc,
152
-------
TABLE A-10.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Vacuum
Filtration Facility
Item
Earthwork
Floor and founda-
tion slab
Precast concrete
wall panels
Roof deck
Interior drywalls
Equipment mezzanine
Misc. structural
Steel frame of
building
Grating
Painting
Cranes
Louvers
Vacuum filter and
ancillary
equipment
Pumps and metering
equipment
Holding tanks
Misc. mechanical
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
4,440
-
855
917
332
1,941
-
-
-
-
-
_
-
-
-
8,485
6.4
1.8
Labor
-
12,261
-
1,566
1,833
1,002
6,507
-
-
-
-
-
_
-
-
-
23,169
17.6
5.0
Concrete
Mate-
rial
-
14,758
40,256
3,798
-
1,028
4,586
-
-
-
-
-
„
-
-
-
64,426
49.0
13.9
Labor
-
3,125
7,104
1,127
-
256
3,223
-
-
-
-
-
_
-
-
-
14,835
11.3
3.2
Rebar
steel
-
14,749
-
426
-
1,082
4,401
-
-
-
-
-
_
-
-
-
20,658
15.7
4.4
Cost
dollars
3,873
49,333
47,360
7,770
2,750
3,700
20,658
13,567
5,303
24,667
9,250
4,933
224,467
13,567
18,500
14,800
464,498
2131,573
100
28.3
Cost
% of
struc-
tural
concrete
_
37.5
36.0
5.9
2.1
2.8
15.7
-
-
-
-
-
_
-
-
-
100
Cost
% of
total
_
10.6
10.2
1.7
.6
.8
4.4
2.9
1.1
5.3
2.0
1.0
48.3
2.9
4.0
3.2
100
153
-------
TABLE A-ll.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
440 1/s (10 mgd) Miscellaneous Structures
Consisting of Internal Maintenance,
Laboratory and Garage Facilities
Item
Earthwork
Foundations and
floor slab
Vertical precast
walls
Roof and coverings
Misc. architectural
and structural
Steel frame of
building
Miscellaneous metal
Laboratory
equipment
Garage and mainte-
nance equipment
Office furniture
and kitchen
equipment
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
2,137
-
2,101
304
-
-
-
-
_
4,542
4.7
1.9
Labor
-
4,738
-
3,438
3,480
-
-
-
-
_
11,656
12.0
4.6
Concrete
Mate-
rial
-
5,234
40,290
8,640
2,900
-
-
-
-
_
57,064
58.6
22.8
Labor
-
1,412
7,110
3,546
2,752
-
-
-
-
_
14,820
15.2
5.9
Rebar
steel
-
5,749
-
1,375
2,164
-
-
-
-
„
9,288
9.5
3.8
Cost
dollars
2,600
19,300
47,400
19,100
11,600
10,200
9,800
30,000
55,000
45,000
250,000
297,400
100
39
Cost
% of
struc-
tural
concrete
-
19.8
48.7
19.6
11.9
10.5
10.1
30.8
56.5
46.2
100
Cost
% of
total
1.0
7.7
23.0
7.6
4.6
-
3.9
12.0
22.0
18.0
100
ADDENDUM - TABLE A-ll
1. Building structural cost is only 40 percent of the total
cost.
154
-------
TABLE A-12.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
44 1/s (1 mgd) Trickling Filter
Item
Earthwork
Tank floor slab
Ventilation wall
Collection trough
floor
Influent center
pier
Perimeter wall
Precast floor beams
Underdrain blocks
Rock fill
Misc. structural
Distributor arm
assembly
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
396
1,672
274
78
2,352
-
-
-
270
-
5,042
6.3
4.0
Labor
-
2,262
5,234
3,654
100
7,608
-
-
-
810
-
19,668
24.7
15.5
Concrete
Mate-
rial
-
4,568
884
-
130
1,244
11,468
7,916
8,430
725
-
35,415
44.4
27.9
Labor
-
1,608
1,930
-
18
1,361
900
3,392
3,140
475
-
12,824
16.1
10.1
Rebar
steel
-
4,304
580
-
256
816
-
-
-
720
-
6,676
8.4
5.2
Cost
dollars
11,427
13,138
10,300
3,928
582
13,381
12,368
11,308
11,620
3,000
36,000
127,052
£ 79,625
100
62.7
Cost
% of
struc-
tural
concrete
-
16.5
12.9
4.9
.7
16.8
15.5
14.2
14.6
3.8
-
100
Cost
% of
total
8.9
10.3
8.1
3.1
.5
10.5
9.7
8.9
9.1
2.4
28.3
100
ADDENDUM - TABLE A-12
1. Low overall height makes reinforcing minimal in base struc-
tural slab; costs are very low compared to base slabs for
sedimentation tanks, digesters, etc.
2. Main cost centers are for materials - rock fill media,
block underdrain system, and precast underdrain block sup-
ports. Labor is minimal with' a rock trickling filter.
Cost reductions would be possible using underdrain block
and precast block support systems.
3. If an outer upturned ventilation wall is employed, the in-
ner wall containing the rock media must be open underneath,
requiring a suspended circular wall - a formwork cost center.
155
-------
TABLE A-13.
CONSTRUCTION AND EQUIPMENT
INSTALLATION COST SUMMARY
44 1/s (1 mgd) Aerobic Digester
Item
Earthwork
Floor slab
Vertical walls
Vertical concrete
baffles
Tank cross beams
Misc. structural
(influent and
effluent)
Mechanical aerators
and ancillary
equipment
Misc. mechanical
Cost - dollars
Cost - % of struc-
tural concrete
Cost - % of total
Formwork
Mate-
rial
-
179
1,638
748
1,000
284
_
-
3,849
8.2
3.3
Labor
-
1,117
3,555
2,083
1,600
1,772
_
-
10,127
21.5
8.8
Concrete
Mate-
rial
-
3,360
4,550
2,667
660
5,330
.
-
16,567
35.2
14.3
Labor
-
600
1,247
269
396
952
.
-
3,491
7.4
3.0
Rebar
steel
-
3,200
3,045
1,392
320
5,056
_
-
13,013
27.7
11.2
Cost
dollars
18,801
8,456
14,062
7,159
3,976
13,394
42,400
7,452
115,700
147,047
100
40.7
Cost
% of
struc-
tural
concrete
-
18.0
29.9
15.2
8.5
28.5
_
-
100
100
Cost
% of
total
16.2
7.3
12.2
6.2
3.4
11.6
36.7
6.4
100
100
156
-------
APPENDIX B
OTHER IDEAS CONSIDERED IN THIS STUDY
A number of other novel and unconventional ideas were con-
sidered during the study. Most of these novel and unconvention-
al ideas were not able to satisfy cost reduction requirements
or engineering integrity considerations. Other ideas are in-
cluded for completions. One, deep shaft treatment, is a process
development extension of a novel or unconventional construction
method; process development was specifically excluded from in
this work. However, an exception was made in the case of the
deep shaft case because process considerations were evaluated
in the course of study on this unconventional construction ap-
proach. Another, septic tanks upstream of sewers is also men-
tioned; this approach is not universally cost-effective but has
application in certain areas. These other ideas are included
in this appendix, as follows:
1. Electron beam ozone generation
2. Shotcrete
3. Concrete dome covers
4. Foam formwork
5. Sheet piled vertical walled tank
6. Mass site excavation
7. Oversize trenching plough
8. On-site wound FRP tanks
9. Deep shaft wastewater treatment
10. Septic tanks upstream of sewers
As indicated in 9 above, deep shaft wastewater treatment is
process related and is discussed in greater detail at the end of
this appendix. Ten above, septic tanks upstream of sewers, is
identified at the end of this Appendix since this approach is
used and was also considered in the study.
157
-------
Electron Beam Ozone Generation
While evaluating the comparative costs of disinfection
processes, it was noted that most of the cost of chlorine con-
tact tankage and all of the cost of dechlorination facilities
could be saved if one of the alternative methods of disinfec-
tion could be more fully developed. The savings represented
would be significant to the overall construction grant program.
A brief novel method analysis was carried out based around an
idea for ozone generation using an electron beam accelerator
to determine the impact on construction cost of the adoption of
such a method.
Development testing with lasers used routinely in the
electronics industry showed great potential for energy savings
in comparison to existing ozone generation techniques. Un-
fortunately, the manufacturer of the laser test unit has not
been successful in scaling up the equipment for prototype test-
ing. Claims of economy in capital and operating/maintenance
cost cannot therefore be accepted at present.
Any potential breakthrough in disinfection should be ac-
tively pursued, as substantial operational expenditure is neces-
sary to cover the costs of the commonly used chlorination
method.
Shotcrete
Shotcrete has several potential uses in wastewater collec-
tion and treatment. In tunneling, shotcreting has b^en used in
Japan to line tunnels without provision of intermediate support.
In tank construction, hoppers have been identified as very high
unit cost items; these have been constructed more cheaply using
shotcreting methods. Consideration has been given to construc-
ting vertically walled tanks using shotcrete. However, this
has at present been rejected, because the necessary wall thick-
ness cannot be built up in a single application.
No particular uses for shotcreting were established during
the study other than a specialized application for tunneling.
Future development of the material in conjunction with other
modern materials might open up new uses.
Concrete Dome Covers
Concrete domes have been constructed by pouring concrete
flat between two membranes and inflating the completed slab to
form a dome. When the concrete has set, doors and windows are
sawn into the green concrete. Reinforcing steel is threaded
through wire spirals to enable it to expand when the structure
is inflated.
158
-------
Covers of aluminum, fabric and fiber reinforced plastic
are considered elsewhere in this report. The potential of con-
crete domes of this type is not considered to be of sufficient
value to warrant further discussion.
Foam Formwork
Methodology—
The forming of complex concrete shapes is very costly using
conventional steel and timber forming materials. The concept
of using a single master form to create a complex shape, and
then to mold multiple forms from the prototype was suggested.
Rigid foamed plastic was recommended as a suitable material for
making the master form out of. Prior to setting, it is fluid
and can be easily shaped. After setting it is rigid, has a
smooth surface, and possesses considerable compressive strength.
Development—
Research uncovered two manufacturers who have experimented
with foam formwork. Both indicated that composite or laminated
foam form structures are necessary for strength and dimensional
stability. The making of these forms is a high technology pro-
cess. One company indicated that foam forms are cheaper than
steel where 40 or more uses can be achieved. The foam forms
have been used for slab construction, vertical walls, and for
complex curved shapes. Neither manufacturer seemed strongly
interested in the potential applications to the construction of
wastewater treatment plants. They felt that the reuse factor
was too low in this application. It was felt that no benefit
would be realized in following this idea further at the present
time.
Sheet Piled Vertical Walled Tank
Methodology—
Conventional methods and materials of construction for
vertical walls in sedimentation/aeration tanks, and similar
shallow excavated tanks, have been identified as high cost
centers. The function of such walls is to resist internal and
external forces, and to retain water.
A variety of ideas were suggested. The idea which was po-
tentially most economical — diaphragm walls — was eliminated
since no suitable method for maintaining long term integrity
was developed. Sheet piling, which is frequently used for tem-
porary excavation support, was suggested to be used in conjunc-
tion with a waterproofing of some type.
Development—
Extending beyond the steel sheet piling concept, the use of
interlocking concrete piles is also possible. Three structural
types are presently available; free cantilever, top restrained
159
-------
(propped) cantilever, and intermediate tied back cantilever.
The tied back cantilever was rejected, because the tie back
anchors nullify the tank's earth's potential for other uses.
The concept was developed and analyzed for one primary tank
76.2 m (250 ft) long by 7.6 m (25 ft) wide by 4.6 m (15 ft)
deep. A 300 x 300 mm (12 x 12 in) concrete beam was used out-
side of the tank at the surface to cap the piles and anchor the
liner. A 600 mm (24 in) high by 300 mm (12 in) wide splay was
used around the interior base to anchor the liner and provide
machinery fixing points.
Costs were developed for the sheet pile tank and for a
concrete tank of the same overall dimensions. Temporary sheet
piling was allowed for in the cost of the concrete tank (two
reuses of the piles assumed). The cost of the sheetpile wall
was approximately 1.5 times the cost of the conventional wall.
It was concluded that there would be no further benefit
from this investigation.
Mass Site Excavation
Methodology—
The excavation of several individual process unit areas
was identified as one construction task that might be improved
upon. The mass site method of excavation was examined as part
of the construction of a minimum size plant. On a conventional
plant, units are more widely spaced. The most cost-effective
method of excavating for the plant is to strip the site to a
general minimum formation level. The equipment best designed
to handle such excavation is used for strip mining overburden
removal.
Development—
The use of strip mining style of equipment would require a
contractor or plant to hire a strip mining company or purchase
such equipment for use on a contract or in an area. It is un-
likely that the use of such equipment on so small a scale would
be cost-effective. To be an economical alternative it would be
necessary for some regional or federal agency to purchase the
equipment, and make it available for rental use by contractors.
The cost of transportation of such equipment was considered
potentially prohibitive. The initial analysis was therefore
centered on determining likely first cost and transportation
costs, a unit cost for excavation using such machinery, and
comparing these costs with the cost of conventional treatment
plant excavation.
It was determined that even if the equipment capital cost
could be offset against many projects, the overall cost of
160
-------
excavation of medium and larger plants using this technique is
higher than conventional methods. No benefits are possible,
therefore, and no further action was taken.
Oversize Trenching Plough
Trench excavation for sewers is a high cost center. One
of the basic limitations with the present backhoe excavation
technique is that it is a two-step process. Soil is cut from
a trench face into a bucket, the bucket then moves to a conveyor
or truck to discharge the material. Dynamic one-step excava-
tion, such as is achieved using a plough, could be more cost-
effective if the required energy input could be developed. A
plough has been developed which excavated a trench for a 900 mm
(3 ft) diameter undersea oil pipeline.^
The plough, developed by R. J. Brown and Associates, cut
2.2 km (1.4 mile) through hard clay to allow positioning of the
oil pipeline. The trench was excavated in just 30 miniutes.
No cost data, nor information concerning maximum depth was
available. It is anticipated that such a device would have
limited value in view of its inability to cross utilities.
There is little likelihood that deep excavations are possible
in other than perfect ground conditions.
On-Site Wound Fiberglass Reinforced Polyester (FRP) Tanks
FRP Tank manufacturers suggested on-site winding of large
diameter tanks. This technique has been used in industry. Pre-
sently only small diameter FRP structures are used at wastewater
treatment plants and these structures are generally prefabri-
cated at the shop and shipped to the site in completed form.
FRP wall thickness can be of any dimension, and this thick-
ness can be varied from the top to the bottom of the walls.
Polyurethane foam in 1 inch thick sheets can be added between
the structural FRP wall and a final FRP protective coating to
provide an insulated tank. Diameters of over 100 feet are
possible,as well as sidewalls up to 50 feet high.
Cost evaluation was carried out for a 30 m (100 ft) diame-
ter tank with a 4.6 m (15 ft) high sidewall. Concrete wall
thickness was assumed to be 350 mm (14 in). The cost of FRP
tankage was based on 7C/litre (28<:/gallon) . The ratio of cost
of FRP wall vs. cost of concrete walls was 4.4 to 1. Therefore,
the proposed FRP method has no advantages over conventional
methods for use in municipal wastewater treatment.
Deodorizing Foul Air with Botanical Systems
Objectionable odors from wastewater interceptors and waste-
water pumping and treatment facilities are sometimes removed by
161
-------
mechanical or biological scrubbing systems. These systems are
ordinarily constructed using conventional materials of construc-
tion (e.g., plastic media and steel tanks). A simpler system
might provide cost savings. Because foul air frequently con-
tains carbon dioxide at concentrations greatly in excess of that
atmosphere, the use of botanical systems (i.e., growing plants
in greenhouses) is an attractive concept which might reduce
construction costs, as well as put the foul air to a beneficial
use.
Greenhouse structures are sometimes used to protect sludge
drying beds from rain. It is possible that foul air might be
routed to such areas and use be made of drying sludge for grow-
ing botanical systems.
A botanical deodorizing system would consist of a green-
house containing appropriately selected plants. Foul air would
be delivered to the greenhouse to provide a carbon dioxide en-
riched atmosphere for accelerated plant growth. Odor reduction
would be primarily from biological oxidation by bacteria on the
plant surface area. Oxygen enrichment of the atmosphere and
the masking effect of pleasant plant odors would also help to
decrease the offensiveness of the gas released from the green-
house.
Implementation—
In order to implement this idea, design criteria would
need to be established and appropriate plants would need to be
selected. Determination of such things as growth-limiting fac-
tors, growth rates, supplemental lighting requirements, oxygen
production rates, and areal requirements must be established to
determine the idea's potential. Design and construction of
greenhouses is ordinarily carried out according to well-
established principles, and only minor design changes would be
required to efficiently distribute the foul air and to collect
the deodorized air for release. Consideration should be given
to a cascade arrangement of greenhouses to reduce the potential
for inadvertent release of odors due to incomplete reaction.
The system for delivering the foul air from its source to the
greenhouse would be the same as for any other deodorizing sys-
tem.
Because the plants grown in the greenhouses potentially
have a marketable value, consideration should be given to har-
vesting and marketing requirements. This effort will be criti-
cal in offsetting the total costs of the botanical system, since
other deodorization methods are relatively cheap. There are no
known regulations or codes which would require change to imple-
ment this concept.
Cost Considerations—
Information on the potential savings in using botanical
162
-------
deodorizing systems are not available. Greenhouse construction
would be cheaper than scrubbing systems due to its simplicity
and less use of steel. Economics would depend heavily upon the
areal requirements for the greenhouses. It is possible that
this concept would be appropriate only at locations where green-
houses already exist.
Advantages—
Botanical systems could be used in areas where the climate
is relatively mild and solar radiation is reasonably consistent
throughout the year. The major advantage of botanical deodoriz-
ing systems would be the potential reduction in material and
construction costs due to its simplicity. An additional benefit
would be harvesting of a marketable by-product, which would put
the foul air to a beneficial use and would reduce overall costs.
Disadvantages—
Botanical systems would be inappropriate in areas where
climatic conditions are unsuitable or would be expensive to
overcome; e.g., where excessive insulation and supplemental heat
and light would be required. Also, the distance of the foul air
source to the greenhouse site, and the availability and cost of
land would be factors affecting the economics of botanical sys-
tems.
WASTE TREATMENT PROCESSES UTILIZING DEEP SHAFTS
Section 7 discussed the most economical construction method
for drilling deep, large and small diameter shafts. The use of
deep shafts for something more than a conduit or reservoir was
pioneered by Imperial Chemicals Industries Ltd., Billingham,
U.K. They developed a treatment process appropriately labeled
"The Deep Shaft Wastewater Treatment Process". Several other
treatment processes are clearly adaptable to deep shaft tech-
nology. Deep shaft applications include those listed below,
each of which will be described briefly.
• Deep Shaft Concept
• Dissolved Air Flotation
• Solids Contact Bed
• Microflotation
• Chlorine Contact
Several of these process units can be paired in combinations to
further increase plant economy.
163
-------
Deep Shaft Concept
This is a deep shaft, of 0.3 to 10 m (1 to 33 ft) in diame-
ter and from about 100 to 300 m (320 to 1,000 ft) deep, in which
waste is biologically oxidized (see Figure B-l). ICI claims
that this process can replace aerobic activated sludge tanks
and anaerobic sludge digestion units. After screening and de-
gritting, wastewater is fed to a concentric pipe (downcomer) in
the deep shaft. Recycled sludge is also fed at this point.
Compressed air or oxygen added in the descending leg provides
oxygen to the system. Essentially, all of the air or oxygen is
dissolved before the stream rises up the outside shaft. Carbon
dioxide, nitrogen, and unused oxygen come out of solution in
the form of microscopic bubbles as hydrostatic pressure de-
creases. Solids are separated from the main stream by clarifi-
cation or flotation and either returned to the shaft influent
as sludge recycle or wasted.
Optimal shaft depth and diameter vary with both hydraulic
and organic loading characteristics and with soils and geology
of the site as they affect the costs of shaft construction.
Typically, optimal shaft depth will be in the range of 50 to
150 (english equivalent) meters (150 to 500 feet), but in some
cases depth may be as much as 200 to 250 meters (600 to 800
feet). At a given treatment site, two or more shafts could be
used instead of only one if such configurations result in over-
all economy in shaft construction, taking into account the
specific geologic conditions present. The changes in pressure
that take place in the liquid as it travels from the top of the
shaft to the bottom, and again to the top aids the oxygen
transfer process. Power consumption is claimed to be modest;
solids separation methods are evidently in the research and
investigative stages to determine the most satisfactory ap-
proach. Flotation is held as a promising way to accomplish
economical and good quality separation by the system developers.
Only limited experience with full scale deep shaft systems
has been reported to date. Several applications for industrial
waste treatment are now operating in Europe and in U.K. In
Canada, a municipal plant employing deep shafts is now operating
at Virden, Manitoba. This installation consists of a shaft 150
meters (500 feet) deep and one meter (3 feet) in diameter de-
signed for a flow of about 25 1/s (0.6 mgd).
The deep shaft treatment system has excellent potential for
being the most economical system for meeting secondary effluent
quality requirements under certain conditions, including:
• Favorable geologic conditions for economical shaft
construction; including shallow, though stable,
overburden and completed rock of medium strength.
164
-------
."•x^ •••••••-
Compressor
INLET £>
^
SLUDGE
RECYCLE
OUTLET
Downcomer
r^* Riser
Shaft
% Lining
FIGURE B-l. ICI DEEP SHAFT UNIT
165
-------
• Relatively high land cost, because the shaft system
uses little land.
• Severe northern and extremely hot climates which
adversely affect conventional treatment.
Under the above conditions, potential advantages compared
to conventional activated sludge treatment are:
• Lower power consumption.
• Lower sludge production.
• No primary settling needed with deep shaft.
• Reduced odor potential.
• Overall lower cost, at least for plants serving
populations in excess of approximately 50,000 people.
Potential disadvantages include:
• A potential risk for groundwater contamination;
however, lining or casing of the shaft should pre-
clude this from occurring.
• Uncertainty in cost owing to high dependency on
subsurface conditions.
• Current lack of experience with the method; in-
cluding, the question of interrelation between
the deep shaft and the other units of the treat-
ment plant.
Dissolved Air Flotation
This process would employ a concentric pipe in a sealed
shaft, approximately 55 m (180 ft) deep, in place of a conven-
tional pressurization system for a dissolved air flotation unit.
This application could provide a low cost, energy-efficient
system for air saturation in dissolved air flotation of waste
activated sludge.
Liquid requiring pressurization and air saturation at ele-
vated pressure would be fed to the pipe. Air bubbles would
then be added to the descending leg of the U-tube. Thus, a
high degree of air saturation would be achieved by the turbu-
lence and static pressure in the system. Sludge and appropriate
chemicals would be added in the upward flow to combine with the
air bubbles, which form as pressure is decreased. The concen-
trated waste activated sludge would be floated in a conventional
flotation tank and removed with skimmers.
166
-------
Solids Contact Bed
This process would present a deep shaft containing a con-
tact bed of high specific surface area media. This configura-
tion offers the promise of eliminating a surface solids separa-
tion step, because the contact bed would also act as an upflow
filter.
After pretreatment, air or pure oxygen would be added to
the wastewater near the bottom of the descending leg of the U-
tube. The high specific surface area contact bed, located in
the ascending leg, would provide a fixed growth medium for the
microbiological culture, as well as a filter to reduce sus-
pended solids. Only a degassification zone would be required
at the surface. A further downstream filtration process might
be required for further additional solids removal.
The fixed growth contact bed could also be designed as an
anaerobic reactor. Air addition high in the ascending leg
would control septicity in downstream processes, and still help
provide fluid motive force.
Microflotation
This process, which has been pioneered by Environmental
Systems Division of AB Electrolux, Stockholm, requires a shaft
of about 8 to 10 m (26 to 33 ft) deep, and employs an unconven-
tional and simple method for generating microscopic air bubbles
(see Figure B-2). Electrolux claims that the process, used in
lieu of a secondary clarifier, can result in a smaller separa-
tion unit (40 minute detention time) and eliminate the need for
waste activated sludge thickening, because it can concentrate
sludge to about 3 percent.
The process is designed for solids separation. After
mechanical pretreatment to remove oversized solids, pH is ad-
justed, flocculant aids are added, and the wastewater is mixed.
Then it flows down the descending leg of the divided shaft.
Air, injected at the bottom of the shaft, dissolves under hydro-
static pressure. Undissolved air rises in the descending leg
and enhances water saturation. The rising stream is then not
only saturated with air, but also free of undissolved air bub-
bles. The dissolved air is released in the form of microscopic
bubbles, that attach to solids as the hydrostatic pressure in
the rising leg decreases. Polyelectrolytes may be added to
improve float density. The float passes into a separation tank
where it is removed by skimmers.
Chlorine Contact Chamber
A deep shaft equipped with an inner tube, or straight par-
tition, is conceived as a method for achieving desired chlorine
167
-------
Sludge tank
Polymer-dosage^
intake
Compressed-air \
intake --—,0
Floccuiation
tank \
Flotation tank
Precipitation-chemical
intake
intake
Aeration sparger'
FIGURE B-2. MICROFLOTATION PROCESS
168
-------
contact time with full assurance that no shortcircuiting can
occur. Chlorine would simply be injected at the upper part of
the inner conduit and circulation would be forcedly eltab-
lt*h™l a dl"ere*tial hydraulic head between the downcomer and
the riser. Liquid with injected chlorine would flow all the
7!SL^ l^e ^om S the shaft' then rise in the outer chamb^
(annulus) and discharge to the effluent outfall conveyance sys-
tern . •*
u ^ 6? mi*ut? contact time, the typical combinations of
shaft depth and diameter are given in Table B-l that are re-
quired to satisfy volume requirements for various design dis-
charges. Multiple shafts can be employed if found to be more
economical for a specific installation; by virtue of the geology
and/or other factors.
Uncertainty in construction cost is the major disadvantage.
This is coupled with an undemonstrated likelihood of significant
cost advantage, particularly for larger size plants. Concern
may be expressed over the potential for the contamination of
groundwater; care in the design and installation of lining or
casing should preclude this possibility, however.
TABLE B-l. SHAFTS FOR CHLORINE CONTACT
Design
discharge
(I/sec)
500
200
100
50
Net I.D-
of shaft
(meters)
2.0
2.4
2.0
1.5
2.4
2.4
1.5
1.0
2.0
2.4
2.0
1.5
1.0
Required
shaft
depth
(meters)
580
400
230
395
160
80
200
460
115
40
58
100
230
Volume
(m3)
1800
1800
720
720
720
360
360
360
360
180
180
180
180
Approximate cost
range for lined
shaft (thousand
dollars)
310-460
—
—
125-185
70-100
—
160-230
_ —
40-50
—
—
80-115
169
-------
Advantages include a relatively long and narrow flow path
with a minimal chance of short circuiting, thus assuring
achievement of desired contact time. The requirement for land
is much less than for surface tankage, and could be a signifi-
cant advantage where land is scarce. Indications are that, with
favorable geology, deep shafts are likely to be cheaper or at
least competitive for small-discharge facilities, but conven-
tional surface tankage will be cheaper for medium to large
capacity facilities. To be more specific, 50 1/s (1 mgd) and
smaller capacities have potential for saving costs with the
shaft method, whereas for 200 1/s (5 mgd) and larger flows the
shaft does not seem to be competitive under average site con-
ditions.
Septic Tanks Upstream of Sewers
Where rural sewerage systems are to be provided in areas
where existing households are connected to septic tanks, con-
tinuance of the use of septic tanks provides primary solids
removal and enables the use of much smaller shallower gravity
piping systems. A disadvantage to be considered is the lifetime
cost of removing septage from the septic tanks.
Cost data were not available on this method when these
novel ideas were developed; subsequent inquiry has revealed that
the University of Wisconsin has implemented a project in
Westboro, Wisconsin involving small diameter gravity sewers
with community subsurface disposal. Construction was completed
during the summer of 1978. Although more information is needed
to evaluate costs and performance such systems appear to be a.
positive solution to cost reduction in rural areas and should
be considered along with pressure and vacuum sewer alternatives
for these areas.
170
-------
REFERENCES
1. New Civil Engineer, July 7, 1977, p. 3
171
-------
APPENDIX C
COMPUTER SEARCHES
The following chart and listing of key words were used
during computer searches for references. The chart shows the
development path for ideas from the origination of the refer-
ence by the computer through to incorporation of the idea in
this report or its rejection. The list shows the key words
developed for the later computer searches (early searches were
by general subject) . These keywords were paired by the com-
puter, i.e., a "Stage/Process" key word and an "Operation" key
word were both required to appear in the key word listing for
any citation.
172
-------
GIVEN SUBJECT
EG EPA, LOCKHEED
SEARCH
DETERMINED
SUBJECT
ELIMINATE
NON-ITEMS
CLASSIFY
UNCONVENTIONAL
SEE
SEPARATE
FLOW
PATH
LISTING OF
SUBJECT TOPICS
IDENTIFY
GAPS
B & C REVIEW
IDENTIFY
REFERENCES
TRACK DOWN
REFERENCES
FURTHER
REFERENCES
DISCARD
EPA NOVEL METHODS _ ™,DATU
PHASE 2 TASK 3 - UNCONVENTIONAL METHOD FLOWPATH
173
-------
Stage/Process
Element
Operation
Activated Sludge
Advanced VJastewater
Treatment
Aeration
Aerobic Digestion
Anaerobic Digestion
Biodegradability
Biological Processes
Biological Treatment
Biological Waste
Treatment
Chemical Treatment
Chlorination
Collection
Denitrification
Digester Gas
Digestion
Disinfection
Equalization
Extended Aeration
Filtration
Flocculation
Flotation
Gas Utilization
Gravity Thickening
Grit Removal
Hydraulics
Land Disposal
Methane
Nitrification
Nitrogen Removal
Nutrient Addition
Ozonation
Phosphorus Removal
Preliminary Treatment
Primary Treatment
Screening
Scum Removal
Seasonal Variations
Secondary Treatment
Sedimentation
Settling
Sewage Treatment
Sludge Dewatering
Sludge Disposal
Sludge Treatment
Thickening
Wastewater
Water Pollution
Control
Activated Biofilter
Activated Carbon
Activated Sludge
Process
Aerated Grit Chamber
Aerated Lagoons
Aerators
Bar Racks
Catch Basins
Centrifuges
Channels
Chlorine Contact
Tanks
Clarifiers
Combined Sewers
Diffusers
Digesters
Digestion Tanks
Filters
Final Tanks
Furnace
Heat Treatment
Incinerators
Lagoons
Manholes
Mechanical Aerators
Microstrainer
Mixed Media Filters
Oxidation Ditch
Oxidation Ponds
Ozonators.
Polyelectrolytes
Polymers
Ponds
Presses
Pumping Stations
Pumps
Regulator Stations
Rotating Biological
Surfaces
Roughing Filter
Sanitary Sewers
Screens
Sewage Treatment
Plants
Sewage Works
Sludge Drying Beds
Stabilization Ponds
Storm Sewers
Thickeners
Trickling Filters
Application Rates
Benefit Cost
Analysis
Capital Costs
Construction Costs
Cost Comparison
Cost Effectiveness
Costs
Design
Economic Analysis
Economics
Efficiency
Facilities
Management
Instrumentation
Loading Rates
Maintenance Costs
Management
Operating Costs
Operating Results
Optimization
Performance
Evaluation
Plant Efficiencies
Power Costs
Process Control
Sensitivity
Analysis
Standards
Transfer
Efficiency
Valxie Engineering
EPA NOVEL METHODS - PHASE 2
LOCKHEED COMPUTER SEARCH KEY WORDS
174
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/2-79-079
3. RECIPIENT'S ACCESSION NO.
ITLE AND SUBTITLE
NOVEL METHODS AND MATERIALS OF CONSTRUCTION
5. REPORT DATE
July 1979 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
. AUTHOR(S)
A. F. Harber and R. C. Bain, Jr.
8. PERFORMING ORGANIZATION REPORT NO
. PERFORMING ORGANIZATION NAME AND ADDRESS
Brown and Caldwell, Consulting Engineers
100 W. Harrison
Seattle, Washington 98119
10. PROGRAM ELEMENT NO.
1BC611; SOS 2A, Task 25
11. CONTRACT/GRANT NO.
68-03-2512
2. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory—Cin.,OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Project Officer: Francis Evans III
(513) 684-7610
16. ABSTRACT The purpose of this study was to identify the structural and nonstructural fac
tors which influence the cost of construction of municipal wastewater treatment plants
and to determine if construction costs could be reduced through the modification of the
nonstructural factors or the use of unconventional or novel methods and materials of con
struction. For nonstructural factors or problems, solutions are posed for some of the
identified problems and these are ranked in terms of their potential for implementation
and cost savings. Within the top six ranked solutions two involved expansion of the fac-
ility planning phase, two involved design criteria while the remaining top ranked solu-
tions involved fast track construction management procedures and adoption of novel ideas.
From the structural aspect, those unconventional materials or methods of construction
identified as feasible and cost effective were flexible (in situ formed) pipe liner whicl
enables sewers to be relined using existing access, plastic fluid control equipment, and
several fiberglass reinforced plastic (FRP) applications including digester covers, small
diameter piping and access bridges for walkways over clarifiers and other process units.
The most readily implementable novel concepts identified were vertical shaft constructio
methods and applications, precast concrete tanks, and reinforced asphalt pond liners.The
best ideas identified as requiring further study are shipboard treatment and botanical
foul air treatment. Other ideas including those considered non-cost effective are identified.
This report is submitted in fulfillment of Contract No. 68-03-2512 by Brown and Cald-
well, Inc., under the sponsorship of the U.S. Environmental Protection Agency. This repor
was essentially completed during the period March 7, 1977 to November 30, 1977; however,
some additional work was conducted during the summer of 1978 which accounts for refer-
ences to the Clean Water Act Amendments which were passed by Congress in December 1977.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COS AT I Field/Group
Waste treatment, Expenses, Construction,
Construction costs, Construction materials,
Building codes, Fabrication, Engineering,
Construction equipment
Wastewater treatment,
Capital costs, Structural
cost centers, Nonstructura
cost centers. Design
standards, Construction
grants eligibility,
Construction grants cost
savings
13B
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
UNCLASSIFIED
!1. NO. OF PAGE!
191
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Fora 2220-1 (Rev. 4-77)
175
OUSGPO! 1979 — 657-060/5448
------- |