ANALYSIS OF AIRPORT
SOLID WASTES AND
COLLECTION SYSTEMS
SAN FRANCISCO INTERNATIONAL AIRPORT
U.S. ENVIRONMENTAL PROTECTION AGENCY
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9273
ANALYSIS OF AIRPORT
SOLID WASTES AND
COLLECTION SYSTEMS
SAN FRANCISCO INTERNATIONAL AIRPORT
This final report (SW-48d) on work performed
under solid waste management demonstration grant no. G06-EC-00294
to the City and County of San FranaisGO Airports Commission
was written by METCALF & EDDY, INC.,
and is reproduced as received from the grantee.
U.S. ENVIRONMENTAL PROTECTION AGENCY
1973
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Additional copies of this publication will soon be
available from the National Technical Information
Service, U.S. Department of Commerce, Springfield,
Virginia 22151.
An environmental protection publication in the
solid waste management series (SW-48d)
This report hoe been reviewed by the 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 commercial
products constitute endorsement or recommendation for use by the
U.S. Government.
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PREFACE
This is the first published study of airport solid
wastes. It focuses on the quantities, kinds, and sources
of the wastes and their storage, collection, and transfer.
Actual field data was gathered at the San Francisco
International Airport. In addition, data was assembled
from 36 other major airports who responded to mailed
questionnaires. Eight of the 36 questionnaires were
supplemented with personal interviews.
Located some 14 miles from downtown San Francisco on
a 3,000-acre site, San Francisco International supports
commercial, general, and some minor military traffic.
The fourth busiest airport in the United States and the
fifth busiest in the Free World, it is typical of the
modern aviation complex—the isolated, self-contained,
expanding institution whose wastes differ in content
from the usual residential and municipal solid wastes.
San Francisco International handles as many as 2,000
aircraft movements daily. On an annual basis, these repre-
sented, in 1971, some 15 million passengers moving through
the airport, ^36 thousand tons of mail and air cargo that
were processed—and almost 15 thousand tons of solid wastes
that were generated.
Although the specific locale for this study was the
San Francisco Airport, the premise of the study is
applicable to other commercial airports. Through a
thorough understanding of waste sources, quantities, and
characteristics, and how these are related to levels of
operation (i.e., numbers of flights, passenger load, air
cargo tonnage), basic planning factors can be developed
for a management system for handling both existing and
projected waste loads. It also could guide in selecting
flexible and economical methods for storing, collecting,
and transporting refuse. This study did not extend to
disposal, and processing was evaluated only as it re-
lated to storage and collection.
iii
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R. Kent Anderson served as the Project Officer for
the Office of Solid Waste Management Programs. Robert G.
Lee was the Project Director for the Airports Commission)
City and County of San Francisco, and Hilary Theisen was
the Project Manager for Metcalf & Eddy, Inc.
—Clyde J. Dial, Director
Systems Management Division
Office of Solid Waste Management
Programs
iv
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TABLE OF CONTENTS
Chapter
1 SCOPE OF THE PROJECT 1
Authorization 1
Scope of Work 1
Approach to the Project 3
2 SUMMARY OF FINDINGS 5
Solid Waste Characteristics 5
Alternative Collection and 7
Transportation Systems
3 PRESENT CONDITIONS 16
Study Area Characteristics 16
Airport and Tenant Activities 18
Existing Solid Waste System 20
Solid Waste Handling Costs 32
Classification of Wastes by Source 33
Weighing Program 33
Physical and Chemical Characteristics 38
Survey of Other Airports 41
Purpose and Scope 41
Solid Waste Systems 42
Management Methods 45
Adequacy of the Existing System 46
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TABLE OF CONTENTS (continued)
Chapter
POTENTIAL MANAGEMENT METHODS 48
Introduction 48
Types of Management Methods 48
Method 1 48
Method 2 49
Method 3 50
Important Planning Considerations 51
Implementation 51
Operations and Environment 52
Finances 53
POTENTIAL COLLECTION AND HANDLING METHODS 55
Introduction 55
Collection 55
Containers 56
Frequency of Collection 57
Collection Routes 58
Collection Vehicles 59
Crew Size 62
Transport 62
Pipelines 63
Vehicles 65
vi
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TABLE OF CONTENTS (concluded)
Chapter
(cont'd)
Appendix
A
B
C
Processing
Compaction
Shredding
Separation
High-Compression Baling
Incineration
Transfer
ALTERNATIVE COLLECTION SYSTEMS
Present and Future Demands for Solid
Waste Systems
Selected Collection and Handling Methods
Potential Locations for Equipment
Selected Management Methods
System Development
Alternative 1
Alternative 2
Cost Analysis
Conclusion
WEIGHING AND SAMPLING TECHNIQUES
SAMPLE OF SURVEY QUESTIONNAIRE
REGULATIONS
Page
67
67
68
69
69
70
71
73
73
76
78
80
81
83
88
93
96
98
121
123
vii
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FIGURES
Number Page
1 San Francisco International Airport 17
2 Refuse Storage Containers at Passenger 26
Terminals
3 Refuse Storage Containers at Air Freight 28
Area
4 Refuse Storage Containers at Aircraft 31
Maintenance Base
5 Typical Compaction Trailer and Tractor 66
6 Typical Cross-section View of Small 72
Transfer Station
7 Projected Quantity of Airport Refuse, 74
1970-1985
8 Alternative Collection System 1 84
9 Alternative Collection System 2 89
viii
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TABLES
Number Page
1 Existing Solid Waste System, San Francisco 22
International Airport, July 1971
2 Collection Vehicles and Internal Routing 24
Used by Private Hauler in Existing Solid
Waste System, San Francisco International
Airport, July 1971
3 Sampling Data - Summary of Quantities of 34
Solid Wastes Collected in One Week, San
Francisco International Airport, July 1971
4 Sampling Data - Quantities of Solid Wastes 37
Discharged per Passenger, San Francisco
International Airport, July 1971
5 Sampling Data - Solid Waste Components by 40
Source, San Francisco International Airport,
July-November 1971
6 Sampling Data - Chemical Characteristics of 40
Organic Solid Wastes by Source, San Francisco
International Airport, July-November 1971
7 Selected Results from National Airport 43
Survey, November 1971
8 Collection and Handling Equipment Costs 77
9 Equipment Evaluated for Use at San Francisco 82
International Airport
10 Equipment and Manpower Requirements and 86
Capital Costs for Alternative 1
11 Equipment and Manpower Requirements and 90
Capital Costs for Alternative 2
A-1 Sampling Data - Quantities of Solid Wastes 103
from Passenger Terminals by Component, San
Francisco International Airport, July 1971
ix
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TABLES (continued)
Number
A-2 Sampling Data - Confidence Range on Data
from Passenger Terminals by Component,
San Francisco International Airport,
July 1971
A-3 Sampling Data - Quantities of Solid Wastes 107
from Air Freight Area by Component, San
Francisco International Airport, July 1971
A-4 Sampling Data - Confidence Range on Data 108
from Air Freight Area by Component, San
Francisco International Airport, July 1971
A-5 Sampling Data - Quantities of Solid Wastes 110
from Aircraft Service Center by Component,
San Francisco International Airport, August-
December 1971
A-6 Sampling Data - Percent Distribution of 111
Wastes Comprising Aircraft Service Center
Wastes by Component, San Francisco
International Airport, August-December 1971
A-7 Sampling Data - Confidence Range on Data 112
for Meal Service Wastes by Component, San
Francisco International Airport, August-
September 1971
A-8 Sampling Data - Confidence Range on Data 112
for Aircraft Wastes (Excluding Meal Service
Wastes) by Component, San Francisco
International Airport, August-September 1971
A-9 Sampling Data - Confidence Range on Data 113
for Service Buildings by Component, San
Francisco International Airport, December
1971
A-10 Sampling Data - Quantities of Solid Wastes 115
from Aircraft Maintenance Base by Component,
San Francisco International Airport, August
1971
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TABLES (concluded)
Number
A-ll Sampling Data - Confidence Range on Data 117
from Aircraft Maintenance Base by Component,
San Francisco International Airport,
August 1971
A-12 Sampling Data - Chemical Characteristics 119
of Organic Solid Wastes by Source and Sample
Number, San Francisco International Airport,
July-November 1971
xi
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Chapter 1
SCOPE OF THE PROJECT
Authorization
Many airports across the nation are developing into
major commercial complexes, often remote from urban areas,
which are generating increasing quantities of solid wastes.
Recognizing the need for better solid waste systems, San
Francisco International Airport undertook this project to
assist in the development of solid waste planning.
The project was authorized by the City and County of
San Francisco through its Airports Commission. Because the
work to be accomplished would have significance for airport
operations in other parts of the country, a federal demon-
stration grant was awarded to assist in the funding of the
project. The contract between the City and County of San
Francisco and Metcalf § Eddy, Inc. (M§E), was executed in
March 1971. A period of 12 months was granted for the
study.
Scope of Work
The two primary objectives of this demonstration proj-
ect were (1) to develop basic information on solid wastes
generated at San Francisco International Airport, and
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(2) to study alternative collection and transportation systems
that might demonstrate engineering feasibility and economic
benefit. To accomplish these objectives, the following major
work items were delineated in the contract:
1. Develop basic information as to the quantities, char-
acteristics, and sources of solid wastes generated at
the San Francisco International Airport.
2. Develop facts regarding the above information as
related to levels of operation, such as number of
flights, passenger load, air cargo tonnage, etc., for
predicting future solid waste loadings. This infor-
mation would have national significance in that it
could be used to compute similar information for other
commercial airports.
3. Study alternative systems for collection, transfer,
and transportation of solid wastes.
4. Select the most feasible system from the standpoint
of suitability, flexibility, and economy, and prepare
a cost estimate for construction of facilities to
demonstrate a system of engineering feasibility and
economic benefit.
Although not specifically identified in the contract
scope, a future planning period up to 1985 was selected to
study alternative collection and transportation systems.
2
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It should be noted that, because of funding limitations,
an evaluation of solid waste disposal systems was not included
in this project. A practical evaluation of collection and
transportation systems, however, must include a limited evalua-
tion of processing systems as an aid to both collection and
disposal systems. Therefore, processing and disposal systems
were considered, but only as they relate directly to collection
and transportation.
Approach to the Project
The management of solid wastes is becoming an important
element in the overall operations of large commercial airport
complexes. The increasing numbers of aircraft passengers,
coupled with the trend toward throwaway packaging and meal
utensils, are producing significant increases in solid waste
quantities. As these wastes continue to increase it becomes
more necessary to use predictive methods in management plan-
ning. Such methods are not now available. Only when a
thorough understanding of waste sources, quantities, and char-
acteristics is achieved can effective waste management methods
be developed.
The approach to achieving an understanding of airport
wastes for this study was one of utilizing the knowledge of
both airport engineers who were familiar with operational
requirements and of consulting engineers and planners
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experienced in solid waste systems. A work program was devel-
oped which split the tasks of this project between the two
teams. All field data and airport planning data were accumulated
by airport personnel under guidelines prepared by the consultant.
Data evaluation and waste management system development were
accomplished by the consultant. Close coordination was main-
tained during all phases of the work. In this way, the know-
ledge and capability of each team was used fully so that
practical and useful results could be attained.
Because this was to be the first in-depth study of airport
solid wastes, a broad survey of many national airports was
included. The approach used was one of mailed questionnaires
to airports to determine their operating levels. These levels
were then compared to those at San Francisco International
Airport to ascertain whether solid waste data derived there
would be applicable on a nationwide basis. If useful results
would be achieved, the planning process for other airports would
be greatly accelerated.
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Chapter 2
SUMMARY OF FINDINGS
The significant conclusions and findings of this study
are presented in this chapter. Detailed background informa-
tion concerning the findings is presented in following chap-
ters. As identified in Chapter 1, the main objectives of the
study were (1) to develop basic information on solid wastes
generated at airports, and (2) to study alternative collection
and transportation systems. The findings are presented
accordingly in two lists.
Solid Waste Characteristics
1. Sources of solid wastes at airports are definable and
are similar throughout large airport complexes around
the United States. These sources were classified,
both by function and by geographic location within
the airport complex, into the following four types of
facilities:
• Passenger terminals
• Air freight area, including mail service facilities
• Aircraft service centers
• Aircraft maintenance bases
2. Solid waste characteristics (weight and composition)
were identified for each of the four sources.
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The characteristics were derived through field data
gathering only at San Francisco International Airport
The significant characteristics of weight and composi-
tion for each source, based on data representing a
composite week of field observations, include the
following:
• Passenger
terminals
• Air freight
area
Aircraft
service
centers
• Aircraft
maintenance
base
Weight,
tons per week
68.7
29.8
133.2
55.6
Primary composition
type
70 percent paper
46 percent paper
17 percent wood
10 percent plastics
34 percent food
32 percent paper
12 percent metal
10 percent plastics
51 percent paper
15 percent food
10 percent plastics
Demolition material, normally generated in large
quantities at an airport complex, was not generated
during the sampling period and therefore could not be
measured.
3. The unit generation values derived for each source are:
• Passenger terminals - 0.53 pound per passenger
• Air freight area - 7.10 pounds per ton of cargo
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• Aircraft service
centers:
Composite of all - 1.02 pounds per passenger
activities
Aircraft flights - 2.51 pounds per passenger
including meal
service wastes
Aircraft flights - 0.54 pound per passenger
excluding meal
service wastes
• Aircraft maintenance - 2.19 pounds per employee
base per day
4. The total quantity of refuse generated on the airport
complex on a holiday (Labor Day) does not fluctuate
significantly from that on a normal weekday. A
possible explanation is the balancing effect of lower
work activity in the maintenance base and service
centers versus higher passenger and cargo activity
at the terminals and air freight area.
Alternative Collection and Transportation Systems
1. The total quantity of refuse generated at San Francisco
International Airport is 287 tons per week. This
quantity is projected to increase to 500 tons per week
by 1985. These figures are based on the following
basic data: passenger loading approximately 15 million
in 1971, projected to increase to 32 million by 1985;
air cargo approximately 436,000 tons in 1971, projected
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to increase to 1,660,000 tons by 1985; employee levels
at the maintenance base approximately 8,000 to 10,000,
projected to increase only slightly by 1985.
2. Existing solid waste systems are controlled individually
by each airport tenant, except in the terminals where
the airport authority controls the system. There has
been very little coordinated planning for the airport
solid waste systems under this fragmented control
condition. Although many different types of efficient
equipment are used, a highly inefficient loose-garbage
room exists in the South Terminal. This is an example
of inadequate and uncoordinated planning. The major
coordination has been achieved by a single hauler who
serves all tenants on the airport. The hauler removes
all wastes from the airport for disposal at a sanitary
landfill located about 15 miles from the complex.
3. Regarding the control of solid waste systems at other
airports, selected results from the survey revealed
that 58 percent of the airports had no solid waste
systems operated by a public agency, while 33 percent
had a combined public-private collection system. In
61 percent of the airports each tenant makes his own
contract arrangements with the private hauler.
4. The existing solid waste collection system has the
following equipment: 30- to 50-gallon storage cans,
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2-cubic yard back-end loading storage containers, 2- to
6-cubic yard front-end loading storage containers, 10-
to 40-cubic yard debris boxes, a loose-refuse room,
stationary compactors, back-end loading trucks, and
tilt-frame trucks. This type of collection system
equipment is common to most of the other airports
contacted during the survey.
5. Demolition material is hauled in debris boxes or stan-
dard earthwork construction vehicles (dump trucks) .
Wood wastes, normally placed in debris boxes, are
disposed of off the airport at the sanitary landfill.
Dirt, broken concrete, and broken asphalt pavement are
disposed of on the airport in areas where the existing
land has subsided and benefits from filling.
6. The existing system removes all refuse from the airport
with only minor interference with airport operations
and limited litter or debris. The system does require
frequent truck traffic in the terminal and passenger
loading pier area, increasing the potential for con-
gestion and equipment damage. Under these conditions,
the cost of the present system could be higher than
that of a system utilizing more efficient equipment.
The cost of the present system of collection and dis-
posal is approximately $20,000 per month, or about
$16.10 per ton of refuse collected.
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7. Collection and handling methods selected as feasible
for evaluation at San Francisco International Airport
as alternatives or modifications to the existing system
were: stationary compactors, debris boxes, wheel
mounted cans (compacted and uncompacted), front-end
loading trucks, towing tractors, and tilt-frame trucks.
Because of their potential benefits to the collection
system, the following processing methods were consid-
ered: shredding, incinerating, and wet pulping.
8. Two collection systems of potential economic benefit to
the airport complex were selected from the various
alternatives evaluated. Both offer significant advan-
tages over the existing system, but the final selection
should be made by the airport commission as discussed
in Item 10. Alternative 1 is a modification to the
existing system, incorporating the wider use of
stationary compactors, debris boxes, and a shredder
for bulky wastes in the air freight area. The equip-
ment might be supplied by private haulers, and system
operation might be continued by private haulers.
Alternative 1 capital costs are $302,000, and annual
costs average $5.20 per ton of refuse handled. Alter-
native 2 is a completely new collection and transfer
system for the airport complex. All existing equip-
ment would be replaced (feasible since most existing
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system equipment is owned by the private hauler) by a
wheel mounted portable equipment system. This system
would serve all tenants and areas of the airport. The
equipment would be purchased by the airport and the
system would be operated by airport personnel. Alter-
native 2 capital costs are $164,000 and annual costs
average $5.60 per ton of refuse handled.
The annual costs and cost savings for two periods (1971
and 1985) under the existing system, Alternative 1, and
Alternative 2 are shown in the following tabulation.
For 1971 refuse For 1985 refuse
quantity(1) quantity(2)
Existing system
Annual cost $128,700 $302,000
Alternative 1
Annual cost 77,700 182,000
Annual savings 51,000 120,000
compared with
existing system
costs
Alternative 2
Annual cost 83,200 195,000
Annual savings 45,500 107,000
compared with
existing system
costs
(1) 14,900 tons per year for 1971,
(2) 34,900 tons per year for 1985
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9. Alternative 1 has the following advantages over the
existing system:
• Present collection trips could be reduced from 70
trips per week to 54 trips per week, and total time
consumed in the airport collection could also be
cut approximately by 50 percent (from 51 hours to
24 hours).
• Lower annual costs would result for all tenants
collectively, although each individual tenant might
have a higher or lower cost, depending on present
in-house collection equipment and contract arrange-
ments .
• Potential interference with aircraft movement would
be greatly reduced.
• Security within aircraft operating areas would be
more easily maintained.
• Refuse would be delivered to a limited number of
collection locations by each tenant, thereby uti-
lizing to a greater degree the in-house equipment
(and its flexibility for both refuse hauling and
aircraft operations) of each tenant.
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Alternative 2 has the following advantages over the
existing systems:
• Solid wastes technology is presently evolving at a
very rapid rate. More efficient processes may soon
be developed. This alternative would be most flex-
ible for adapting to future change.
• Through an integrated management system operated
exclusively by the airport, tenants would collec-
tively benefit from lower annual costs and also from
future changes in technology that might require a
large amount of investment to update the system.
• Although the collection time and number of pickups
would be nearly equivalent to the existing system,
airport security would be increased under Alter-
native 2 because airport personnel would be oper-
ating on collection routes. Interference with
aircraft operations would also be minimized because
the towing tractors and containers are approximately
the same size as baggage handling equipment widely
used around aircraft.
10. On the basis of the reported cost savings, the airport
should change its refuse collection procedures. The
changes in equipment that have shown a potential for
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benefit are related to container size and location.
The equipment with the greatest benefit potential has
been identified in Alternatives 1 and 2. The final
determination of the alternative to be used should be
based upon the degree of operational control the airport
wishes to maintain over refuse collection operations.
Three management methods have been identified and are
listed below.
• Method 1 - The airport commission maintains full
operational control over the entire refuse handling
function (collection, transport, and disposal). All
equipment is the property of the commission, and
tenants are billed for the service provided.
• Method 2 - The airport commission shares management
with the tenants. Shared management ranges from
complete control (nonoperational) of management by
the airport to 99 percent control by the tenants.
• Method 3 - The airport commission leaves all manage-
ment, including refuse collection and disposal
functions, in the control of each tenant. Only an
enforcement control is maintained over the tenants
to the extent of safeguarding aircraft movement,
the environment, and public health.
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If the airport continues with collection service by
private haulers, Alternative 1 should be implemented,
If operational control by the airport is important,
Alternative 2 should be implemented. With either
alternative, however, the airport authority should
play a stronger future role in controlling its solid
waste system.
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Chapter 3
PRESENT CONDITIONS
Study Area Characteristics^
The San Francisco International Airport is a large commer-
cial airport complex located in San Mateo County, California,
approximately 14 miles south of San Francisco. The total land
area within the airport boundaries is approximately 3,000 acres.
The physical details of the airport complex are shown on Figure
1. With San Francisco Bay as a boundary on two sides, the
airport is somewhat remote from population concentrations and
associated solid waste producing activities. Commercial and
industrial facilities have developed in areas adjacent to the
airport, however, and solid waste service is provided in these
areas.
As might be expected from the location -of the airport
along an estuary, the underlying soils of the airport contain
significant quantities of decomposing organic materials. This
condition causes high rates of soil consolidation and settlement-
a factor which must be considered when underground waste collec-
tion systems are evaluated.
The configuration of mountains to the west of the airport
causes very strong winds during the afternoon and early evening.
Such winds are strongest in the summer when ocean fogs move
in over the coast mountains. Air temperatures are affected
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ICIL E IK MET
SERVICE CEKIEIS
III RCI1FT lllNTEMtNCC !*SE
SCHEOULfD fOII COHS:>C';TI3N
ACTIVITI CUSSIFI OTIOM IOUNO*IT
17
FIG. I
SAN FRANCISCO INTERNATIONAL AIRPORT
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by these atmospheric conditions, especially in the summer.
The average temperature during the summer ranges from 72 degrees
during the day to 54 degrees at night. Annual precipitation
is approximately 19 inches, and 90 percent of this occurs in
the period from November through April.
Airport and Tenant Activities
San Francisco International Airport is one of the busiest
in the United States. All major airlines use the facility
on a regular schedule. In addition, the airport handles general
aviation traffic plus some minor military traffic. Support
facilities include major aircraft overhaul shops, aircraft
service centers, terminals, and a hotel. Passenger loading
(enplaning and deplaning) during 1971 was approximately 15
million. The total amount of air freight and mail in 1971
was approximately 925 million pounds. A significant quantity
of solid wastes is generated by support activities for an oper-
ation of this magnitude.
There are more than 40 tenants in the airport complex.
The majority are airlines providing passenger, air freight,
and aircraft service. Other tenants include supplementary
passenger service businesses, such as banks, car rental agencies,
restaurants, and mail service, and support services for aircraft
operations, such as fuel farms, flight kitchens, and flight
training. Normally, similar services are located close to
18
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each other. Therefore, the tenants may be classified on the
basis of their geographic locations within the airport, as
well as by their function, into four main sections: (1) passenger
terminals, (2) air freight area, including mail service facilities,
(3) aircraft service centers, and (4) aircraft maintenance
base. The locations of these four main sections are shown
on Figure 1.
The passenger terminals (in two separate buildings) pro-
vide all types of services that are convenient to and used
by passengers. The most significant generation of solid wastes
at the terminals takes place in the food and baggage service
areas of each airline.
The air freight area, which provides all air freight and
mail services, generates a large quantity of solid wastes con-
sisting mostly of bulky packing and shipping materials.
The aircraft service centers, spread around the airport
complex, are hangars that provide aircraft supplies and minor
maintenance. Interior cleaning service for arriving planes
is also provided by a crew from the service center. These
cleaning wastes are brought back to the service center for
future collection.
The aircraft maintenance base provides services for major
repairing and overhaul of aircraft. There is only one such
base at San Francisco International Airport, as shown on Figure
1. The base, a facility of United Air Lines, consists of
three major departments: Maintenance, Engineering, and Supply.
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The complete base is similar to an industrial plant, and the
solid wastes generated are typical industrial wastes (oil sludges,
plastics, metals, paper, wood cratings).
The airport has experienced rapid growth in the past 10
years. Future planning by airport tenants will be based upon
this growth pattern, resulting in continued construction activ-
ities during the near future. Limited space availability will
eventually stop area expansion, but remodeling of facilities
to fit new aircraft equipment will continue. Future planning
does not include any significant changes (such as an additional
maintenance base for a second airline) by any of the existing
tenants. Passenger loading piers and terminal facilities are
presently being expanded, however, and this will substantially
increase the generation of solid wastes at the terminals.
Existing Solid Waste System
The existing system for airport solid wastes comprises
three major parts: (1) in-house handling, (2) collection and
transport, and (3) disposal. In-house handling is defined
as the movement of refuse by a tenant (includes airport oper-
ations personnel) to a collection point for handling by a second
party. It is normally performed by each tenant, except in
specific areas of the passenger terminals such as ticket counters
and rest rooms, where it is performed by airport operations
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personnel as a part of the utility service. Collection and
transport, defined as the picking up and movement of refuse
after in-house handling, as well as disposal, are presently
provided by a private hauler. The hauler collects all wastes
generated at buildings and hangars inside the airport complex
and transports them to a privately-owned landfill site located
about 15 miles from the airport.
At present, solid waste systems are managed by many inde-
pendent tenants. The airport management, on behalf of tenants
in the terminal only, contracts with the South San Francisco
Scavenger Company to collect and transport the solid wastes
generated from the terminals and the passenger loading piers.
Other than this, the airport management has not become involved
in the management of solid wastes generated by tenants. His-
torically, each tenant has managed its solid waste activities
independently without consulting with the airport management
or other tenants. Because few private haulers are available
for contract hauling in the vicinity of the airport, almost
all tenants have contracted with the same one. The airport
management has never attempted to integrate all activities
into a single system.
The existing solid waste system at the airport is described
in Tables 1 and 2. The data shown in Table 1 include the types
of containers used by the tenants, the types of collection
vehicles used by the private hauler, and the collection frequency
As a general practice, containers are furnished by the private
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Table 1
EXISTING SOLID WASTE SYSTEM
San Francisco International Airport
July 1971
Collection vehicle
Source and
loot ion
Tenant
Containers ,
number and si:e (cy)
Front -end Back-end
loader loader
Pull-on
truck
Collection
frequency
Passenger terminals:
1.
2.
3,
4.
S.
«.
7.
Air
1.
2.
3.
4.
5.
6.
7.
1.
9.
Central and South
Terminal buildings
Airport parking
Miscellaneous
Pier F
Pier £
Pier D
Pier C
freight arcs:
Cargo 1
Cargo J
Cargo 4
Cargo 5
Cargo <
Cargo 7
P. 0. building
Flying Tiger hangar
Miscellaneous
buildings
Airport operation
Avis Rent-a-Car
Airvay Equip. Rental
Hertt
Host International
National Car Rental
DeLaval
Airport Garage
Yellow Cab
Contractor H.V. Olsen
Bank of America
Western Airlines
PSA
Delta
Serv-Air-Calif.
Miscellaneous Tenants
Airlift International
TWA
American Airlines
Pan American
Delta Airlines
Japan Airlines
Qantas
Airport Mall Facility
Flying Tiger
Wheeler Animal
Shelter
South Pacific Air
Freight
WTC Air Freight
Philippine Airlines
14 - S'xZ'xJ' (1)
10 - J'xZ'xl.S' (1/3)
1 - S'x2'x3' (1)
1 - S'x2'xJ' (1)
1 - S'xZ'xJ1 (1)
6 - S'x2'xJ' (11
3 - S'x2'xJ' (1)
1 - S'xZ'xJ' (!)
Barrels
2 - S'xZ'xJ' (1)
1 - S'xZ'xJ' (1)
1 - S'xZ'xJ' (1)
Barrels
3 - 6'xS'xS' (6)
2 - 6'xS'xS' (6)
1 - 6'x5'xS' (6)
1 - 12'x7'x5' (14)
1 • S'xZ'x3' (1)
1 - 12'x7'xS' (14)
1 - 6'x4.S'x4.S' (5)
1 - 12'x7'xS' (14)
1 - 14'x8'xS' (16)
1 - 6'x$'x5' (6)
1 - 14'x8'xS' (16)
1 • 6'xS'xS' (6)
2 • S'xZ'xJ' (1)
2 - 22" diara x 36"
4 • 6'x3'x3' (2)
1 - 12'x7'xS' (14)
1 - 12'x8'x5' (14)
1 - S'x2'xJ' (1)
Barrels
3 - S'xZ'xJ' (1)
Barrels
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
3-4/day
3-4/day
J-4/day
J-4/day
S-4/day
3-4/day
3-4/day
3-4/day
3-4/day
3-4/da>
3-4/week
6-7/week
Z-3/week
3-4/day
Z-3/week
3-4/week
2-J/week
2-J/week
6-7/wcek
2-J/week
Z-3/week
J-4/day
J-4/day
«-7/week
J-4/week
I-2/week
I/week
1-2/day
1-2/day
J-2/day
22
-------
Table 1 (continued)
Collection vehicle
Source and
location
Aircraft service
centers;
1. Hangars (service
buildings)
Z. Other Itations
Aircraft aatntenanee
base:
1. United Air Lines
Maintenance Base
Tenant
American Airlines
Airborne Freight
Nestern Airlines
TKA
United Air Lines
PSA
A>ir Nest
North Western
National Airlines
Pan American
U.S. Coast Guard
Butler Aviation
Air California
Shell Oil Depot
Standard Oil
Satellite
S.P. Unified School
District facility
United Air Lines
Containers, Front-end Back-end
number and size (cy) loader loader
S - 6'xS'xS' (6) X
1 - 6'xS'x5' (6) X
5 - 6'xS'xS' (6) X
S - 6'xS'xS' (6) X
1 - 32-cy compactor
box
5 - 6'xS'xJ' (2) X
4 - 6'X*.S'X4.5' (5) X
2 - 6'x-t.S'x4.S' (S) X
I - 6'xS'xS' (6) X
1 - 6'xS'xS' (6) X
1 - 40-cy compactor
box
1 - 12'x7'xS' (14)
1 - «'x2'x3' CD X
2 - S'x2'xJ' (1) X
Barrels X
Barrels X
Barrels X
1 - 40-cy compactor
box
1 - U'xS'xS' (16)
Pull-on Collection
truck frequency
6-7/veek
5-4/veek
S-A/veek.
6-7/weck
X 6-7/wcek
6-7/veek
6-7/week
6-7/veek
l-2/«ek
I/week
X 3/week
X 2/week
S-4/diy
1-2/d.y
1-2/day
1-2/d.y
1-2/d.y
X 6-7/week
X I/week
23
-------
Table 2
COLLECTION VEHICLES AND INTERNAL ROUTING USED
BY PRIVATE HAULER IN EXISTING SOLID WASTE SYSTEM,
San Francisco International Airport
July 1971
Type of vehicle
Collection route
f]. Approximate tint
Daily scheduled1' for each intern»l
collection time Collection frequency collection, ain
Back-end loader Hilton—-South Terminal— Piers—*
Garage——• Central Terminal—••
Standard Oil— UAL .Service —*•
HTC Air Freight — Cargo 7
7:00 a.m. - 8:00 a.m.,
11:00 a.m. - 1:00 p.m.,
10:00 p.m. - 2:00 a.m.,
4:00 a.m. • 6:00 a,n.
Front-end loader Kestern—» Air West —. Post Office—*• 12:30 a.a. - 2:30 a.m.
PSA —» Airborne— AA —• Cargo 7-»
UAL— Pier D and F — TKA
Pull-oa truck
Compactor box:
PAN-AM
UAL Service Center
UAL Maintenance Base
Debris box:
Delta, UAL (MB), AA, TNA
FTL, U.S.C.C., others
7:00 a.m. - 8:00 a.m.
7:00 a.m. - 8:00 a.m.
7:00 a.m. • 8:00 a.m.
irregular
on call
5 or 4/day
I/day
every other day
every other day
irregular
60
45
75
JO
150
IS
IS
IS
(1) The daily schedule ii very flexible, with the actual collection time set at the convenience of the hauler.
hauler for storing the refuse after in-house handling and prior
to truck collection. Containers vary in types and sizes, depen-
ding upon the tenant's need and the storage situation. The
collection schedules and routes are described in Table 2. Addi-
tional details on collection in each of the four main airport
areas are presented in the following paragraphs.
1. Passenger terminals. As seen from Table 1, the termi-
nal complex includes a variety of tenants. The in-
house handling of refuse is done by each tenant. The
equipment used is normally of the janitorial type
(brooms, waste baskets, miscellaneous containers, etc.)
After in-house handling, the refuse is placed in the
collection containers. In the passenger terminals,
most of the wastes are deposited in three large refuse
24
-------
rooms (two in the Central Terminal and one in the
South Terminal) where wastes are stored for collection,
In the Central Terminal rolling containers of approxi-
mately 1-cubic yard capacity are usually positioned in
each room for storing refuse at the completion of in-
house handling. A photograph of the container is
shown on Figure 2. In the South Terminal refuse is
thrown loose on the floor of the refuse room. A
photograph of the refuse room is also shown on Figure
2. The hauler then shovels or throws the refuse into
his collection truck. He collects from the terminal
refuse rooms three or four times each day, and from
other terminal areas as described in Table 2,
2. Air freight area. The in-house handling of freight
and air mail wastes is done by each tenant. The
containers and equipment used include standard
janitorial containers plus special freight handling
equipment for hauling the bulky packaging waste.
All packing wastes do not remain at the airport for
collection and disposal since the crating and un-
crating of freight is normally done off the airport
complex. Those wastes that are generated in the
freight area result from additional crating or break-
age. After in-house handling, refuse is stored for
collection in front-end loading containers and debris
25
-------
PORTABLE BACK-END LOADING CONTAINER
LOOSE-REFUSE ROOM
FIG. 2
REFUSE STORAGE CONTAINERS AT PASSENGER TERMINALS
26
-------
boxes. Photographs of the containers and debris box
are shown on Figure 3. The bulky nature of the wastes
requires containers with large volume capacities. The
contents of these containers are hauled either to a
transfer point or directly to the landfill.
Aircraft service centers. Refuse from the service
centers includes both hangar wastes and aircraft
passenger wastes. In-house handling for hangar wastes
is done by janitorial type service. In-house han-
dling for aircraft passenger wastes is done in
several different ways. The most significant of
these involves wastes from flights serving meals.
When the tenant has a flight kitchen at the airport,
wastes from aircraft are taken to the service center.
This in-house handling is done by tenant cleaning crews
using special cleaning equipment, containers, and a
truck. Refuse is taken from the aircraft, often in
special portable containers (used to hold food and
drinks at the originating airport, then to hold
refuse as the food and drinks are used) , and placed
into a truck for delivery to the service center.
Additional in-house handling at the service center
includes hand separation of food wastes for grinding
and disposal to the sewer at several locations, and
paper and other wastes for delivery to a storage
27
-------
PORTABLE FRONT-END LOADING CONTAINER
STATIONARY FRONT-END LOADING CONTAINER
PULL-ON DEBRIS BOX
FIG. 3
REFUSE STORAGE CONTAINERS AT AIR FREIGHT AREA
-------
container and collection by the private hauler. Those
airlines without flight kitchens have catering services
provided by off-airport caterers. The in-house handling
of meal wastes for these airlines includes the
caterer, since he removes meal wastes in the portable
containers in which meals were delivered. In this
instance, those wastes do not become a part of the
airport wastes. However, a change in the supplier
of flight meals could cause a significant increase in
wastes to be handled. For these airlines, the internal
aircraft cleanings (dirt, newspapers, etc.) are handled
by cleaning crews. These cleaning wastes are normally
taken by truck to the service center, although an
airline with limited support facilities at the service
center may dump such wastes into containers located at
the terminal passenger loading piers.
After in-house handling, service center refuse is
placed in front-end loading containers or stationary
compactor containers for further collection. The
contents of these containers are hauled directly to
landfill, except when the tenant has provided a
separate container to store salvageable metals.
Several airlines have these special containers out-
side their hangars and sell the metals to scrap
dealers.
29
-------
4. Aircraft maintenance base. As noted previously, the
single maintenance base at San Francisco Interna-
tional Airport is similar to an industrial complex.
In-house refuse handling, therefore, involves more than
normal janitorial service. Two full-time in-house
collectors are employed to collect refuse in more
than one hundred 2-cubic yard rolling containers
using a small power tractor. The rolling containers
are located throughout each plant department and are
collected once a day during the day shift and moved
to a 40-cubic yard stationary compactor for storage
and collection. A photograph of the stationary com-
pactor is shown on Figure 4. Some of the bulky and
dense wastes are placed in an open 32-cubic yard debris
box for storage and collection. These containers are
hauled directly to sanitary landfill by the collector.
Because this is an industrial complex, there are
additional special in-house waste handling systems.
Industrial sludges (oils, paint strappings, heavy
metal coatings) are stored for periodic pumping and
removal by the private hauler. Also, special salvage
containers are used to store metals for a scrap dealer.
There are miscellaneous unorganized refuse collection
activities not itemized above. Examples are demolition wastes
and sewage sludge. As a part of the total waste handling
30
-------
STATIONARY COMPACTOR WITH AUTOMATIC DUMPING DEVICE
FIG. 4
REFUSE STORAGE CONTAINERS AT AIRCRAFT MAINTENANCE BASE
31
-------
system their impact is small. Only when a major structure is
demolished does the quantity of demolition waste become signifi-
cant. It is then normally handled as a part of the construction
contract with wood materials disposed of outside the airport and
dirt, concrete, and broken asphalt used for fill material on the
airport complex. Sewage sludge is normally processed as a part
of wastewater treatment and is not included in this study of
collection systems.
Solid Waste Handling Costs
The total solid waste handling costs should include the
cost attributed to in-house handling, in addition to the fees
paid to the private hauler. The cost of in-house handling
for tenants at the airport was not available since the cost
of janitorial service, which includes both building cleaning
and refuse collection, is very difficult to split apart. Also,
tenant records of maintenance crew activity often do not even
identify the waste handling function. The collection and dis-
posal costs, however, are available through the monthly bill
from the private hauler. Each tenant was asked to provide,
for the purposes of this study, his average monthly bill for
refuse collection and disposal. The reported total cost for
all airport tenants is approximately $20,000 per month. The
unit collection cost, as quoted by the private hauler, is $4.00
per compacted cubic yard and $2.15 per loose cubic yard. This
32
-------
unit service cost varies with the account, depending upon the
size of the account and the degree of difficulty in pickup.
Classification of Wastes by Source
A primary objective of this study was to develop infor-
mation, in the form of predictive unit values, regarding refuse
generation at the airport. To accomplish this, source and
quantity data were developed from a weighing program and from
a physical and chemical classification program. The results
are summarized in the following subsections; the detailed pro-
cedures and data are presented in Appendix A.
Weighing Program
The weighing program was set up to determine both the
total quantity of refuse generated within the entire airport
complex and the portion of that total generated by each of
the four major types of facilities within the airport previously
described. In addition, a weighing of the wastes directly
discharged from the aircraft was also conducted. The results
of that weighing are included under the service center category.
To gain a meaningful result that represents existing solid
waste practices, a one-week period was selected for the weighing
of all the refuse generated at the airport. This weighing
program was accomplished in the late summer of 1971 by a
33
-------
four-man team from the Engineering Department of San Francisco
International Airport. The results are given in Table 3.
Table 3
SAMPLING DATA - SUMMARY OF QUANTITIES OF
SOLID WASTES COLLECTED IN ONE WEEK
San Francisco International Airport, July 1971
Tons
Source ^^^
Passenger terminals^ '
Air freight area
Aircraft service
centers '*>
Aircraft maintenance
base
Total
Mon. Tues. Wed
9.0 10. S 9.
S.I 5.5 3.
29.8 IS. 5 23.
IS. 8 7.7 7.
59.7 37.2 44.
. Thurs.
9
3
0
8
0
13.
3.
13.
7.
38.
7
4
6
8
5
Fri
7.
4.
14.
7.
35.
8
8
6
8
0
Sat.
9.1
S.2
15.7
..«>
30.0
Sun
8.
4.
21.
8.
42.
Total
7
S
0
7
9
68
29
133
55
287
.7
.8
.2
.6
.3
(1) Defined as 7:00 a.m. from the day shown to 7:00 a.m. of the following day.
(2) Includes wastes from passenger aircraft that are discharged to the
containers around the piers, but excludes wastes from Hilton Hotel.
(3) Includes wastes from passenger aircraft that are discharged to the
containers located at the service center.
(4) No waste is hauled on Saturday.
The daily total amounts varied from 30.0 tons on Saturday
to 59.7 tons on Monday. The total refuse generation from all
San Francisco International Airport activities in one week
was 287.3 tons. This figure excludes the wastes from the Hilton
Hotel, which is located on the airport premises, because hotel
service was not considered a normal part of airport activities.
The largest quantity of waste comes from the aircraft service
34
-------
centers, as most aircraft wastes are handled through this point.
In those few cases where aircraft wastes are discharged to
containers around the terminal piers, the quantities were included
as a part of the passenger terminal wastes.
Since the weekly generation datum was to be used in estab-
lishing average annual refuse generation figures for the airport,
it was necessary to examine the change in generation caused
by a busy holiday weekday. This special weighing program was
conducted on Labor Day in September 1971. The results showed
that the one-day refuse generation was 35.1 tons subdivided
as follows: passenger terminals, 11.2 tons; air freight service
area, 8.5 tons; aircraft service centers, 7.3 tons; and main-
tenance base, 8.1 tons. These data indicate that the refuse
generation on a holiday does not differ greatly from a normal
weekday. The reason might be the balancing effect of work
activity at the different refuse sources on holidays. The
increase of passengers and the accumulation of mail and cargo
tend to increase the wastes at the terminal and cargo areas,
whereas the slowdown of work at service centers and the main-
tenance base tend to decrease the wastes at those areas.
The total weight of refuse generated in one week is believed
to be an average value that can be used for projecting future
waste quantities. To be useful in projections, each source
(as shown in Table 3) should have a unit of waste generation
identified that is directly related to the quantity of waste
from that source. Examples would be number of passengers,
35
-------
number of flights, or square feet of floor space in service
centers; number of flights or cargo tonnage in air freight
service; and number of aircraft, number of employees, or square
feet of space in maintenance bases. The units considered most
representative and the unit generation of solid wastes for
each source are:
• 0.53 pound per passenger for the terminals,
• 7.10 pounds per ton of cargo for the air freight area,
• 1.02 pounds per passenger for the service centers, and
• 2.19 pounds per employee per day for the aircraft
maintenance base.
As mentioned, the weighing of wastes discharged directly
from aircraft was done through a separate measuring program.
A summary of these weights, along with flight information,
is shown in Table 4. The quantity of wastes from aircraft
was proportional to the number of meals served, the types of
meals served, and the total flight time. Unit quantity values
ranged from 0.18 pound per passenger to 3.76 pounds per passenger
The average weight of wastes was 2.51 pounds per passenger
for meal service flights where meal wastes were discharged
at the airport. The weight of wastes per passenger where
flight meal wastes were removed from the airport complex by
caterers and where no meals were offered on the flight was
0.54 pound per passenger. These per passenger figures are
used in Chapter 6 for the projection of solid waste generation
36
-------
Table 4
SAMPLING DATA - QUANTITIES OF SOLID WASTES
DISCHARGED PER PASSENGER,
San Francisco International Airport
July 1971
Destination
I. Passenger
Salt Lake -
San Francisco
Portland -
San Francisco
Omaha -
San Francisco
Honolulu -
San Francisco
New York -
San Francisco
Tokyo -
San Francisco
Average
II. Passenger
Los Angeles -
San Francisco
Long Beach -
San Francisco
Las Vegas -
San Francisco
Salt Lake -
San Francisco
Seattle -
San Francisco
Vancouver -
San Francisco
Kansas City -
San Francisco
Total
flying
time
aircraft wastes
1 hr 33 min.
1 hr 33 min.
1 hr 33 min.
1 hr 33 min.
3 hr 20 min.
* hr SO min.
4 hr SO min.
6 hr S rain.
13 hr 0 min.
13 hr 0 min.
Meals,,,
served11'
B
B
B
B
B
SB/B
SB/B
D
D/SB/B
D/SB/B
aircraft wastes excluding meal
1 hr 3 min.
1 hr 3 min.
1 hr 5 min.
1 hr 13 min.
1 hr 33 min.
1 hr 38 min.
1 hr 59 min.
3 hr 18 min.
Washington, D.C. - 5 hr 22 min.
San Francisco
Pittsburgh -
San Francisco
Cincinnati -
San Francisco
Average
6 hr 16 min.
6 hr 16 min.
none
none
none
B
none
B
D
B
L
B
B/SB
Number
of
stops
0
0
0
0
0
0
0
0
0
b
service
0
0
0
0
0
0
0
0
0
1
2
Total
solid wastes
discharged,
Ib
82.1
52. 1
6S.O
72.1
55.2
219.0
235.2
349.0
325.6
465.0
wastes^"
68.1
30.6
17.0
8.0
14. S
24. S
20.0
25.0
24.0
28.7
25.6
Number
of
passengers
48
36
46
29
31
83
88
101
96
124
73
40
48
31
82
82
21
48
23
88
66
Solid wastes
discharged
per passenger,
Ib
1.71
1.79
1.47
2.48
1.72
2.64
2.69
3.46
3.40
3.76
2.51
0.86
0.77
0.35
0.26
0.18
0.30
0.95
0.52
1.04
0.33
0.39
0.54
(1) B, L, D, and SB represent breakfast, lunch, dinner, and snack, respectively.
(2) The meal service wastes, which are normally separated at the cleaning service, were not
included in the samples. The wastes included were sweepings, paper towels, etc.
37
-------
for those areas where wastes are considered to vary with the
number of passengers.
For the interpretation of the unit quantity values presen-
ted here, it should be noted that separate and different passen-
ger loading data were used to derive the terminal and service
center values from those used to derive the aircraft values.
In deriving the terminal and service centers' values, total
annual refuse quantities were divided by total annual passenger
loadings. The passenger aircraft values were derived by di-
viding the quantity of refuse from each aircraft by the number
of passengers on that flight.
Physical and Chemical Characteristics
As a first step in determining waste characteristics,
a review of the physical and chemical testing methods availa-
ble for airport solid wastes was completed. By observation
it was noted that most of the airport wastes were paper and
corrugated paper boxboard, plastic products, food wastes, and
wood pallets. The following nine categories were selected
for the classification of airport wastes:
1. Paper and paper products
2. Plastics
3. Food wastes
4. Wood and wood products
38
-------
5. Trimmings
6. Metal and cans
7. Glass, stone, and ceramics
8. Dirt and demolition materials
9. Miscellaneous wastes, such as rubber, rags, and
leather, etc.
The development of refuse characteristics was aimed at
these categories to provide basic data for the selection of
waste handling, processing, and recycling methods.
The sampling technique for physical composition followed
APWA (American Public Works Association) standard procedures.
Wastes from the four main airport sections were sampled and
subjected to statistical analysis. The summary result is shown
in Table 5. The percentages of refuse components shown reflect
clearly the types of areas from which the refuse is generated.
The passenger terminals generate a large quantity of paper
wastes; the air freight area discharges mostly bulky cardboard
boxes and wood pallets; the aircraft service centers throw
away a lot of waste foods and metal cans ; and the maintenance
base combines all types of wastes and shows the characteristics
of an industrial complex.
The organic portion of all refuse samples from all sources
was subjected to shredding and subsequent chemical analysis.
Moisture content and volatile solids and ash tests were con-
ducted. These two tests provide information on the chemical
and physical nature of refuse that may be needed for selecting
39
-------
Table 5
SAMPLING DATA - SOLID WASTE COMPONENTS BY SOURCE
San Francisco International Airport, July-November 1971
Percent in weight (mean values)
^~-""- — »^^ Source
Component ^~^~~--^^^
Paper § paper
products
Plastics
Food wastes
Hood fi wood
products
Trimmings
Metal $ cans
Glass, stone,
$ ceramics
Dirt f, demolition
materials
Miscellaneous
Total
Passenger
terminals
70.6
5.3
S.3
3.3
0.2
6.1
4.1
1.8
3.3
100.0
Air
freight
area
45
10
3
17
2
7
3
4
6
100
.7
.0
.2
.1
.6
.7
.3
.4
.0
.0
Aircraft
service
centers
32
10
33
2
0
11
4
0
4
100
.1
.3
.6
.5
.9
.0
.9
.7
.0
Aircraft
maintenance
base
50
9
14
S
0
5
9
0
3
100
.9
.5
.9
.0
.8
.6
.9
.4
.0
Table 6
SAMPLING DATA - CHEMICAL CHARACTERISTICS OF
ORGANIC SOLID WASTES BY SOURCE
San Francisco International Airport, July-November 1971
Percent (mean values)
^~""~-»^^ Source
^~-^^^^
Content *- — ^^^
Passenger
terminals
Moisture 25.4
Volatile solids 90.9
Ash 9.1
Air
freight
area
20.5
89.5
10.5
Aircraft
service
centers
28.5
91.9
8.1
Aircraft
maintenance
base
16.5
93.6
6.4
40
-------
waste processing methods. Results of the analyses are shown
in Table 6. The average moisture content ranged from 16.5
to 28.5 percent by weight; volatile solids, from 89.5 to 93.6
percent; and ash from 6.4 to 10.5 percent. It is important
to note that these percentages were of total organics and not
of total sampled refuse, since the inorganic materials were
separated prior to shredding and testing.
Survey of Other Airports
Purpose and Scope
As mentioned in Chapter 1, a survey of other airports
was conducted as a part of this study in an attempt to deter-
mine what types of solid waste systems and management methods
are used throughout the country. The following criteria were
used in selecting the airports.
• Airport location (wide geographic distribution de-
sirable) .
• Capacity of passenger service (larger facilities
preferred).
• Volume of air freight (large volume preferred).
• Types of aircraft served (wide variety preferred, both
domestic and international flights).
• Physical layout of the airport (both spread-out and
concentrated layouts desirable).
It was hoped that the data gathered from the survey would help
to establish the general validity of refuse generation parameters
41
-------
set by sampling at San Francisco International Airport. For
example, if another airport wishes to use the San Francisco
refuse parameter of pounds per passenger per day in selecting
equipment, it would be important to know if the quantity measured
at San Francisco was similar to the quantity that must be handled
at another airport.
The survey was conducted by mailing questionnaires to
selected airports, and then by conducting personal interviews
with management personnel at certain airports that received
the questionnaire. A sample of the questionnaire is included
in Appendix B. The questionnaires were mailed to 46 airports,
and responses were received from 36. Interviews were held
at 8, A compilation of selected data contained in the returned
questionnaires is included in Table 7. A brief interpretation
of that information is presented in the following subsections.
Solid Waste Systems
The most widely used storage container is the 2- to 6-
cubic yard front-loading equipment. Of airports responding,
67 percent used this type of container. Generally, the larger
and more efficient containers are used at the larger airports.
Some large airports may use every container size, from 1-cubic
yard through 30-cubic yard compactors.
Transfer of refuse to increase the efficiency of trans-
portation to the disposal site is practiced at 14 percent of
42
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Table 7
SELECTED RESULTS FROM
NATIONAL AIRPORT SURVEY, NOVEMBER 1971
Total number of airports responding: 36
Number of Percent of
Item airports total
Solid Waste Systems
1. Types of storage containers used
Less than 1 cy 10 28
1 to 4 cy rear loading 16 44
2 to 6 cy front loading 24 67
10 to 20 cy pull-on debris boxes 11 Jl
Larger than 30 cy compactor 11 31
Open storage requiring shoveling 1 3
2. Transfer 5 14
3. Recycling 1 3
4. Waste discharge point used for aircraft
Service center hangar 4 11
Containers at piers 26 72
Terminal refuse rooms 4 11
Containers at the terminal 1 3
Centrally located compactors 2 6
Management Methods
1. Types of agencies collecting solid wastes
Private 21 S8
Public 1 3
Airport 2 6
Combined (public or airport and private) 12 33
2. Types of contractual arrangements
Each tenant does all contract negotiation 22 61
without assistance from the airport
authority
Each tenant does all contract negotiation 1 3
with rate control by the airport
authority
Combination of above 1 3
Airport authority represents all tenants 3 8
with no exclusions
Airport authority represents all tenants 6 17
but tenant may elect to be excluded
3. Solid waste collection activity interference
with aircraft operations
Frequently 0 0
Occasional 1 3
Seldom 11 30
Never 24 67
4. Up-to-date solid waste planning
Yes 7 19
No 29 81
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the airports. This figure is expected to increase in the future
as disposal sites become more limited and remote.
Processing and recovery of refuse is becoming a more sig-
nificant aspect of planning for solid waste systems. Several
airports presently have tenants who have installed incinerators
or wet pulping units to improve the efficiency of refuse collec-
tion and transport. However, the high capital cost of processing
equipment has limited its use in an airport complex where the
total quantity of waste has been small. Only the Sacramento
Metropolitan Airport now practices recycling, and there only
cardboard is recovered. In addition to high capital cost,
a further deterrent to processing and recovery is the lack
of nearby markets for the recovered materials.
Because of the significant quantities of refuse generated
on aircraft, each airport was asked at what point this mate-
rial was collected and in what type of container. An effi-
cient application of equipment at one airport might be adapted
to others. It is indicated in Table 7 that 72 percent of the
airports discharge aircraft wastes to containers located at
the loading piers. Although this is the most commonly reported
container location for all airports, the authorities contacted
during the personal visits expressed concern that solid waste
handling in this location may conflict with the increasing
number of aircraft movements. Also, the importance of security
in aircraft movement areas is now becoming more widely recog-
nized, thereby limiting the freedom of vehicle movement.
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Management Methods
Data on the management of solid waste systems were gath-
ered from the questionnaire in an attempt to identify any sig-
nificant trends or successful modifications of methods commonly
used on an airport complex. A majority (58 percent) of the
airports are served exclusively by private haulers. The next
largest group (33 percent) is a combined management of private
haulers (usually serving each individual tenant) and public
or airport haulers (usually serving the terminal area). Each
tenant handles his own contract arrangements with the private
hauler in 61 percent of the airports, while 31 percent of the
remaining airport authorities exercise some amount of control
in arrangements with the private haulers. Each method of con-
tracting seems acceptable since interference with aircraft
operations is reported as practically nonexistent in 97 percent
of the airports.
Airport personnel were also asked if any up-to-date planning
for solid waste systems was being done. The greatest number
(81 percent) responded that no planning had been done or was
now underway. Although individual tenants or private haulers
might have underway or completed planning studies unknown to
the airport officials, the widespread existence of such studies
is not expected.
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Adequacy of the Existing System
Before ending a discussion of the present conditions of
solid waste systems both at San Francisco International Air-
port and at other airports around the country, it is worth-
while to comment on the adequacy of existing systems. The
primary function of the system is to collect and remove refuse
efficiently and with limited effect on the environment. Is
this now being done, and if not, what is the potential for
its being done in the future?
Existing solid waste systems are effectively collecting
and removing materials within most airport complexes. The
detailed review of the existing San Francisco International
Airport system revealed that it includes most of the more
practical and efficient containers and trucks available.
Environmental problems are minimal. One problem is that of
blowing papers at the piers in the terminal area, which nor-
mally occurs under a high wind condition when front-loading
containers are emptied. A second environmental problem is
caused in the areas where stationary compactors are used.
Because the refuse thrown in compactor containers often is
wet garbage, a leachate develops at the interface of the com-
pactor and container. This leachate is presently collected
and routed to the sanitary sewer at only one of the three com-
pactor installations on the airport. Although the San Francisco
International Airport treats all storm drainage waters and
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therefore does not discharge leachate directly to San Francisco
Bay, airports should require that leachates be discharged to
a sanitary sewer for subsequent treatment.
The solid waste management method at San Francisco Inter-
national Airport is adequate in most areas of the complex.
The terminal buildings are the greatest problem. Access to
the existing refuse rooms is difficult by collection truck,
and because of the container size used there, the hauler must
make three to four trips per day to collect wastes. This is
inefficient. The number of collection trips and costs could
be greatly reduced by increasing container size and using more
compactors.
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Chapter 4
POTENTIAL MANAGEMENT METHODS
Introduction
The management of solid wastes is growing more complex as
airports become larger and waste quantities become greater.
With increasing costs, more attention should be given to coordi-
nated management in an attempt to improve the efficiency of
solid waste systems. Alternative management methods should be
considered in an attempt to develop the most efficient combina-
tion of collection, transport, and disposal of solid waste.
In this chapter, potential management methods are de-
scribed. Potential solid waste systems are described in
Chapter S.
Types of Management Methods
After a review of airport operations (including those at
San Francisco and other visited airports), three primary manage-
ment methods were identified and selected for evaluation.
Method 1
The airport authority maintains full operational control
over the entire refuse handling function (collection, transport,
and disposal). All equipment is the property of the authority,
48
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and tenants are billed for the service provided. The charac-
teristics of this system are as follows:
a. The airport authority makes a final decision on the
solid waste system activities that are acceptable for
the total airport complex.
b. Prices for refuse service for all tenants are set by
a single authority.
c. Capital and operational costs for the system are
borne by the authority and paid for by the user charge
Under this method, the airport authority plays a major
role in providing refuse service to its tenants. This is a
function that public agencies do not now normally undertake
for commercial and industrial entities.
Method 2
The airport authority shares management with the tenants.
The sharing can take place in many ways, ranging all the way
from complete control (nonoperational) of management by the
airport to 99 percent control by the tenants. Primary charac-
teristics of this method are as follows:
a. The airport authority, acting as the control agency
for the tenants, awards a franchise on a competitively
bid basis for refuse collection and disposal.
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b. Within limits, each tenant selects the collection
system best suited to his needs.
c. Capital and operational costs are incurred by pri-
vate industry.
Under this method, the airport authority is directly
involved in evaluating refuse systems as to environmental
effects and economies, but relies on private industry to
provide refuse service.
Method 3
The airport authority leaves all management, including
refuse collection and disposal functions, in the control of
each tenant, maintaining only an enforcement control over
tenants to the extent of safeguarding aircraft movement,
the environment, and public health. The characteristics
of this system are as follows.
a. Each tenant provides for refuse removal activities
independent of the airport authority, either through
contract with a private hauler or by using his own
system.
b. The function of the airport authority is only regula-
tory, thereby diluting the potential for recognizing
and installing refuse systems that would benefit the
airport complex and the environment.
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Under this method, the airport authority plays a minor
role in selecting new refuse systems or improving existing
systems. Each tenant evaluates his system, and any modifi-
cations to that system are accomplished on an individual
cost-benefit analysis.
Important Planning Considerations^
Before making a final decision on the selection of a
management method, the airport authority should recognize
the important considerations involved. These concern imple-
mentation, operations and environment, and finances.
Implementation
Implementation involves organizing all of the elements
of a selected management method so that operations can begin.
The most important consideration here usually relates to pro-
viding the transition from an existing method to a new or
modified method. In the case of a new or modified method,
the transition may be extremely difficult. An example would
be changing from private hauler contracts with each tenant to
a negotiated contract between the airport and the hauler. A
change from any of the existing methods to a new one may re-
quire extensive capital investment, financing, and changes to
existing operational procedures.
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Management Methods 1 and 2 show the greatest internal
implementation potential because a strong public agency, the
airport authority, can act directly to improve collection
efficiency for the entire airport complex. Under Method 3,
the individual tenant may have difficulty implementing a
method of areawide benefit within his specific lease area.
Careful method selection is necessary if the implementation
problems are to be overcome.
Operations and Environment
Operational requirements for the airport would vary
significantly according to the method selected. Under
Method 1, full operational control, the airport needs the
men and equipment to accomplish daily refuse collection
and hauling. The arrangements for disposal would also have
to be handled by the airport. Vehicle maintenance facili-
ties and storage buildings would be operated by airport
personnel. In contrast, Methods 2 and 3 would not require
the operation of any part of the collection, transport, and
disposal system by the airport.
Total effect upon the airport environment is a primary
concern in assessing the advantages of each method. Method
1 offers the best opportunity for public control of environ-
mental effect. An airport complex is a highly developed
commercial area that is exposed to constant public scrutiny
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in heavily traveled sections such as the terminal, a fact
often overlooked under Management Methods 2 and 3. Manage-
ment under these methods often considers only individual
tenant development of cost-benefit without regard for area-
wide environmental effects.
Finances
The capital required to purchase, install, and operate
a solid waste collection system is an important consideration
in selecting a management method. The initial capital outlay
may be a large amount. Funding such amounts is included
under finances, along with an evaluation of interest rates,
billing methods, and bond alternatives.
The control of financing varies with the different man-
agement methods. Under Method 1, the airport authority must
set the financing program. The sources of funds are general
obligation bonds and revenue bonds. Each tenant would be
billed for service at a level to pay back the bonds, cover
operational expenses, and meet administration costs. Under
Methods 2 and 3, financing would be done by each tenant,
either through direct capital investment at prevailing inter-
est rates or by paying a private hauler a service fee which
covers capital, operating, and administrative costs. In
assessing the impact of financing on the desirability of each
method, it should be noted that private industry can obtain
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capital much faster than a public agency if immediate changes
are needed. However, private capital is usually more expen-
sive than that acquired through public bonds, thereby increas
ing the long-term cost of the system.
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Chapter 5
POTENTIAL COLLECTION AND HANDLING METHODS
Introduction
Before proceeding with the evaluation of alternatives and
selection of a recommended system, it is important to consider
the general characteristics of steps in the handling of refuse
from point of generation through disposal. As set by the scope
of work for this study, the only step to be evaluated was col-
lection (including in-house handling). However, subsequent
transport, transfer, and processing are an integral part of
refuse handling and must be considered when evaluating collec-
tion. An evaluation of the existing methods and of modifica-
tions or more efficient combinations of them is presented in
subsequent sections of this chapter.
The in-house handling step is difficult to remove from
individual tenant control (a no-control condition for the air-
port) and therefore is not evaluated here.
Compaction is discussed as a separate process, although
it can be used as a part of transfer stations or within col-
lection vehicles.
Collection
The aspects of collection that must be analyzed are size,
type, and location of refuse containers, frequency of collection,
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collection routes, type and size of collection vehicles, and
size of crew. Typical unit costs for collection range from
$8 to $25 per ton.
Containers
The alternatives for refuse containers at the individual
pickup points include the following: metal or plastic bar-
rels (usually 32-gallon size); enclosed metal boxes, either
wheel mounted (usually 2- to 10-cubic yard) or stationary
(usually 2- to 6-cubic yard), that may be emptied into a collec-
tion truck or may be hauled individually to the disposal site;
larger debris boxes (usually 10- to 30-cubic yard) that are
pulled onto a tilt-frame truck bed for delivery to the disposal
site; and large compaction-type metal boxes (10- to 40-cubic
yard) that are either pulled onto a tilt-frame truck bed or
are complete trailers in themselves.
The selection of container type is determined largely
by the collection equipment utilized; discussions of this are
included within the subsections entitled "Collection Routes"
and "Collection Vehicles." The container size is dependent
upon quantities and types of refuse generated and upon frequency
of collection; further details are given in the following sub-
section. The location of refuse containers is determined by
convenience to those generating the wastes, by convenience
to those collecting the wastes, and by general overall appearances
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In commercial and industrial areas such as the airport,
the pickup point for refuse is usually established to suit
the operations and convenience of the tenant. In most indus-
trial areas and in well planned commercial areas, this location
is also suitable for the collector, but in areas with poor
vehicular access the location may result in added time and
expense for collection.
Frequency of Collection
The frequency of collection is related to the rate at
which the wastes are generated, the size of the container in
which they are stored, and the potential health hazard they
may represent. Collection from such mass wet-garbage producing
sources as restaurants and flight food kitchens should be at
least once a day for proper health protection.
Non-food wastes (from commercial and industrial areas)
create no health problems and thus may be collected as gen-
eration rates dictate. In some areas, this may be several
times in one day; in others, it may be once every two weeks
or even longer. Collection may be either on a regularly sched-
uled basis or an on-call basis; both are used by the tenants
at the airport. It is important, however, that collection
be frequent enough to prevent the wastes from ever becoming
a visual nuisance.
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There must be a balance between size of container and
frequency of collection. In wet-garbage producing areas, fre-
quency of collection is dictated by health considerations,
and the required container size is automatically determined
by the volume required to contain the maximum amount of refuse
generated in the interval between regular pickups. In other
areas, there is an economic balance between size of containers
and frequency of collection. Too small a container would require
too frequent collection. An oversized container, on the other
hand, might never be filled within a reasonable period and
thus would require extra time and effort for handling a large
unit to collect a small amount of wastes. In areas exhibiting
uniform conditions, the balance between container size and
collection frequency can be theoretically derived. For most
conditions, however, a knowledge of the collection system and
visual observation of container contents are sufficient for
recommending changes in container size and number or in collec-
tion frequency. At present, the private hauler and each tenant
work out the proper balance independently of other tenants.
Collection Routes
Efficiency of vehicular movement dictates that a collection
route should be in as compact a geographic area as possible.
Accordingly, containers within a given area should be as stan-
dardized as possible to allow uniform service from a single
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collection, vehicle. Different types of containers require
different types of collection vehicles, and it can be highly
inefficient to have several collection routes through the same
area just to service different types of containers. Some dif-
ferences in container types will be required to serve the differ-
ent sources of wastes properly, but the variety should be kept
to a minimum. Since different types of containers are actually
needed in a given system, it is probable that they will require
different frequencies of collection, which will necessitate
separate collection routes anyway.
The number of stops along a collection route is set by
the number that can reasonably be accomplished in a working
day. This will vary with type of in-house handling, size of
collection crew, type of collection vehicle, vehicular access,
distance between pickup points, terrain, haul distance to trans-
fer station or disposal site, and weather.
Collection Vehicles
There are several types of collection vehicles, and some
types are available in several sizes. Many of the vehicles
are designed to coordinate with only one type of container,
so flexibility becomes a problem in selecting solid waste equip-
ment. The more common types of vehicles in use today are de-
scribed in the following paragraphs. Most of these are used
by the private hauler who serves San Francisco International
Airport.
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One common type of vehicle-container system is the self-
loading front-end compaction system. Truck capacities usually
range from 20 to 35 cubic yards. Individual containers are
lifted over the truck cab (using the truck hydraulic system),
and dumped into a top opening immediately behind the cab. After
the dumping cycle is completed, the contents of the truck are
compacted by means of a hydraulically operated blade that achieves
a volume reduction of about 4 to 1. A one-man crew is used,
and that man need never exit from the cab of his truck to perform
the collection duties along his route. The front-end loader
may also be obtained as a noncompaction unit. In balancing
the cost of a compaction unit against that of the noncompaction
unit, the extra load-carrying capabilities of the compaction
unit must be considered. Typical unit costs range from $9.00
to $12.00 per ton, depending on haul distance to the landfill.
A second type of vehicle-container system is the back-
end loader. Truck capacities usually range from 15 to 26 cubic
yards. The usual containers for this system are 32- to 50-
gallon metal or plastic barrels, although somewhat larger units
may also be used. A wheeled container (usually 1- to 2-cubic
yard capacity) is available that can be emptied into a back-
end loader using the hydraulic system of the truck. Because
of the relatively small size of all the containers, the back-
end loading system is ordinarily used only within residential
areas. However, space for larger commercial type containers
is limited in some areas of the airport, so small containers
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have been used and may be needed in the future. Crews of one
to three men (including the driver) may be used on back-end
loaders. The refuse is partially compacted by a hydraulic
compaction blade that achieves about 3 to 1 volume reduction.
In deciding on the use of a back-end loader, the flexibility
it offers for loading loose refuse by hand often is an important
factor. Typical unit costs for back-end loader systems range
from $13.00 to $19.00 per ton, depending on haul distance to
the landfill.
A third type of vehicle-container system is a tilt-frame
truck and debris box. The large metal debris boxes are stationed
in areas that produce large volumes or bulky types of refuse.
When full, the boxes are pulled onto the trucks and taken to
the disposal site for emptying. One-man crews are used. In
areas where large volumes of readily compactible refuse (e.g.,
a maintenance or terminal area) are produced, a self-compaction
debris box may be used. In evaluating the use of this equipment,
the combination of in-house handling methods and debris box
location is important. The larger the debris box, the larger
is the area that may be served and the more extensive must
be the in-house handling that delivers the refuse to the box.
Typical unit costs range from $6.00 to $17.50, depending on
whether or not contents are compacted and on distance to the
landfill.
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Crew Size
The significant increase in labor costs over recent years
has had the same effect in refuse collection as in other fields
an emphasis on increasing automation and decreasing manpower.
Accordingly, the trend in development of refuse collection
equipment has been away from the traditional back-end loaders
with multi-man crews toward systems using one-man crews.
As indicated in the preceding subsection, the only major
equipment in use today with multi-man crews is the back-end
loader. In choosing the optimum size for a refuse collection
crew, one must consider an economic balance between the effi-
ciency gained by having several men load a truck and the labor
time lost by having those same men sit idle while they ride
to the disposal site and back.
Transport
Transport is defined here as the moving of refuse from
a collection point to another area for additional processing
or disposal. Considerations in selecting a means of trans-
port include the following:
1. The wastes should be moved efficiently and
economically from one area to another.
2. The wastes should be fully contained to prevent
dust, litter, and possible health hazard.
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The transport methods available for use at the airport
include pipeline and vehicles. Vehicle (truck) transport is
presently used by the private hauler to remove refuse from
the airport complex to a disposal site. Both pipeline and
vehicle transport systems are discussed in this section.
Pipelines
Pulping and Wet Transport. The pumping of a slurry of
refuse and water through a pipeline from in-house processing
to a collection point is defined as wet transport. Transporting
refuse in this way is normally done for only short distances
and within a limited number of buildings. At San Francisco
International Airport, the candidate areas for installing such
a system are the terminal complex and the aircraft maintenance
base. In-house processing is normally done by a grinding or
pulping device similar to a home garbage disposal unit. These
devices are larger than home grinders, ranging in size from
5 to 40 horsepower. After grinding, the slurry either flows
by gravity or is pumped to the collection point where an extrac-
tor removes the water, and the remaining solid material is
placed in a container for subsequent processing. As described
here, wet transport is not a complete transport system because
additional vehicle transport is normally necessary to deliver
the solid waste to a disposal site.
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The wet transport system is usable at the airport only
as an in-house handling system, and has been included in this
discussion only because its beneficial effects extend beyond
the in-house system. The unit cost of the wet pulping and
transport system would range from $1.50 to $6.60 per ton under
normal conditions.
Dry Vacuum Transport. Within the past 10 years, a new
method of pipeline transport of solid wastes has been intro-
duced. This transport system moves dry unprocessed domestic
refuse (no bulky items) by air-stream from individual collec-
tion points to a central processing, transfer, or disposal
station. The system is still in the development stage, but
problems are being worked out on a large (30-ton per day) system
completed in 1971 at Disney World in Florida. That system
size is comparable to the present 287.3 tons per week (40 tons
per day) of refuse generated at San Francisco International
Airport.
A dry vacuum transport system might serve the entire air-
port complex. However, an areawide installation would require
extensive excavations in existing paved areas for a large-
diameter buried pipeline (12 to 20 inches), and thus may not
be feasible. Construction costs under these conditions would
be higher than normally expected. The unit cost of the dry
vacuum transport system would exceed $10.00 per ton, depending
on the size of the collection area.
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Vehicles
Trucks. Transport of refuse in trucks has been the tradi*
tional method of moving waste materials after collection.
Often, the same truck is used for both collection and transport,
but refuse may be transferred from small trucks to larger trucks
for subsequent transport.
The unit costs for a transport system using transfer trailers
are dependent upon labor costs and vehicle maintenance costs.
The range is from $0.08 to $0.13 per ton per mile. Transport
costs within an airport complex are low because the longest
haul distance without leaving airport boundaries will normally
be from 1 to 2 miles. Internal transport costs in this case
are included with collection costs.
Other Vehicles. Vehicles other than trucks can be used
within an airport where the standard refuse truck is too large
to serve an area with limited space or where it would interfere
with aircraft operations on the parking apron. Since size
is the most critical factor in those cases, smaller vehicles
are normally used. One example is the powered towing tractor
used to pull baggage carts. In a refuse movement application,
a tractor could serve the aircraft passenger loading piers
by towing rolling refuse containers from generation points
within operational areas to a collection or loading area outside
operational areas for transfer to a larger vehicle. A conceptual
drawing of typical equipment is shown on Figure 5.
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t* Jaraty-/fa\:
SOURCE: AMS CO., FRESNO, CALIF.
FIG. 5
TYPICAL COMPACTION TRAILER AND TRACTOR
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The unit costs for transport vehicles of this type are
based on equipment and operator costs. Full utilization is
important to obtain a low unit cost because a single towing
vehicle and operator has the capacity to serve many rolling
cans. Since this is an internal transport system (total mileage
of transport is low), the unit cost is expressed on a per ton
basis, not per ton per mile. This cost ranges from $2.00 to
$3.60 per ton as estimated for San Francisco International
Airport.
Processing
Processing methods that have been developed and that are
important to collection and transport include compaction, shred-
ding, separation, and high-compression baling. These processes
are discussed in the following subsections. Additionally,
incineration is important to the airport collection system
when it is used as a volume reduction process by individual
sources of refuse (tenants). Of the processes, only compaction
(in collection vehicles and containers) is presently used in
the airport's system.
Compaction
The process of compaction is used most effectively in
conjunction with transfer stations. The purpose is to reduce
the number of transport vehicles by consolidating the loads.
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There is, however, a practical limit to the amount of compaction
that may be attained. If the loads are too tightly packed,
unloading becomes problematic. In addition, over-compaction
may produce load weights in excess of the vehicle's tolerance
or in excess of highway load limits. Compaction may be achieved
either in a loading chute at the transfer station or in the
transport vehicle itself. The cost of compaction is minimal
and adds only $0.10 to $0.20 per ton to the total annual costs
of transfer.
Shredding^
A shredder is used to reduce solid wastes to a uniform
size. Examples of shredding equipment are shears, pulpers ,
and different types of mills. Recently developed shredders
are designed to process all types of heterogeneous refuse with-
out the necessity for pre-separation of heavy or bulky items.
A shredder can be used in combination with other processes.
Until recently, shredding was considered only as a preparation
of solid wastes for immediate disposal, but now it has proven
to be a beneficial first step to other processing methods.
Examples of this are included in research now underway on separ-
ation and incineration at Menlo Park, California, and high-
compression baling at San Diego.
Shredding costs are dependent upon the processing sequence
in which a shredder is used. As a separate process, total
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annual costs for shredding would be approximately $5.00 per
ton of refuse processed.
Separation
The process of segregating solid wastes into individual
components is known as separation. It is used in combination
with other processes, usually to aid in the recovery of specific
materials. The separation can be accomplished by a variety
of methods: hand picking, magnetic separation, vibrating screens,
flotation, and air classification. Hand picking is the most
commonly used method, but its efficiency is very low. All
other methods require size-reduction processing (shredding)
prior to separation.
The operating costs ($0.50 - $14.00 per ton) for separa-
tion are usually included in a combined processing cost with
shredding, incineration, or disposal.
High-Compression Baling
High-compression baling is a process that produces high-
density refuse bales. The range in density is from 50 to 70
pounds per cubic foot. At such densities, the volume is reported
to be only 20 percent of the volume taken up by the same refuse
in an uncompacted state. The use of high-compression baling
for solid wastes is a recent development, and data from full-
scale operations are not yet available in sufficient quantities
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for complete evaluation. As might be expected, the bales are
economically advantageous in long-distance transportation of
refuse. They also have advantages in sanitary landfills, although
the condition of the bales after an extended time period in
a landfill has not been fully established. Research in disposal
of baled refuse in an ocean environment is presently being
conducted as a part of airport expansion in Hawaii.
The total annual costs for baling are expected to range
between $3 and $5 per ton of refuse processed. The costs will
vary with the type of auxiliary equipment that may be used
to seal the bales before disposal.
Incineration
Incineration is a means of processing a large volume of
solid wastes under controlled burning conditions to produce
for disposal a much smaller volume of inert ash and residue.
The particulate and gas emissions from modern installations
are controlled by particulate removal equipment and by addi-
tional combustion chambers. Incineration is not usually pre-
ceded by any other processing, although shredding of refuse
is proving advantageous for better combustion, and the separation
and removal of selected noncombustibles prior to incineration
also improves combustion. Recent developments in incineration
include the addition of electrostatic precipitators for par-
ticulate removal and the addition of heat energy conversion
systems to provide steam or to generate electricity.
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Incineration of solid wastes must be evaluated in con-
nection with final disposal of the residue. It is an excellent
method of reducing solid waste volume but does require skilled
operators.
Total annual costs for incineration are dependent upon
the type of furnace installed and the method of particulate
discharge control. Typical annual costs range from $8 to $12
per ton of refuse processed. These quoted costs do not include
any allowance for potential revenue from the sale of steam
or electric power because the market for those products is
limited at this time.
Transfer
Transfer stations provide a means of reducing the costs
for transportation of refuse between the point of collection
and the point of processing or disposal. Although it is neces-
sary to have a relatively large number of vehicles of different
sizes to serve the refuse collection needs of an airport complex,
it may prove costly to have each of those vehicles transport
its load to the processing or disposal point.
To make the use of a transfer station economically feasible,
the savings in transportation costs must be at least sufficient
to offset the extra equipment and handling costs. Transfer
stations will naturally be more economical for systems utilizing
multi-man collection crews than for systems with one-man crews,
depending on the hauling distance.
71
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Transfer costs are dependent upon the type of facility
constructed. A typical cross-section view of a small transfer
station for airport use is shown on Figure 6. Total annual
costs (composed of operation and maintenance expenses plus
amortization of capital costs) range from $0.35 to $2.60 per
ton of capacity, excluding the capital cost of transport vehicles
The higher costs include compaction equipment, a building,
and dust collection equipment.
PREFABRICATED
METAL BUILDING
SECTION A=A
FIG. 6
TYPICAL CROSS-SECTION VIEW OF SMALL TRANSFER STATION
72
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Chapter 6
ALTERNATIVE COLLECTION SYSTEMS
Present and Future Demands for Solid Waste Systems
The existing demand for an efficient waste collection
and removal system is evident from the quantities (average
of 287.3 tons per week) measured and reported in Chapter 3.
Collection equipment can be selected and the associated man-
power can be planned for under these existing conditions.
However, the equipment and equipment locations selected on
the basis of present waste quantities of systems might
become inadequate as quantities increase in the future. To
assist in planning, therefore, San Francisco International
Airport specified that system evaluation be done for a period
up to 1985.
Future demands for solid waste systems were projected
to 1985 based on projected passenger loadings and air cargo
tonnage to that time. The future refuse quantities are
shown on Figure 7. The quantities were derived by multi-
plying future passenger loadings, air cargo tonnage, and
maintenance base employees by solid waste parameters (pounds
per passenger, pounds per ton of cargo, and pounds per
employee) developed during the weighing program. The param-
eters are listed in Chapter 3. These projections are
extremely sensitive and subject to change because of the
73
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35 r
30
20
10
I
I
1970
1975
1990
YEAR
TOTAL A| IF-OIIT REFUSE
AIRCRAFT SERVICE
CENTER REFUSE
PASSENGER TERMINALS
REFUSE
AIR FREI8H T
AREA REFUSE
AIRCRAFT MAINTENANCE
BASE REFUSE
1985
FIG. 7
PROJECTED QUANTITY OF AIRPORT REFUSE, 1970-m5
74
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uncertainty of air travel projections. For example, passen-
ger traffic at the airport stopped increasing in 1970, and
has remained at a constant level through 1971. Because of
this and the potential for changes in flight equipment, air-
port planning and associated projections do not often exceed
a period of 5 years into the future, thereby making long-
term projections difficult. For this study, the airport did
provide an estimate of passenger loadings anticipated in
1985. This future estimate was used to form the projections
for refuse quantities from the passenger terminals and ser-
vice centers. Historical records were used to develop an
annual growth rate of 10 percent in air cargo tonnage, and
this rate was used to develop the projection for refuse from
the air freight area. Finally, maintenance base refuse pro-
jections were made on the basis of a 5-year employee growth
rate extended at a constant level through 1985.
Solid wastes requiring special handling (sewage sludge,
demolition material, and industrial sludges) will continue to
exist on the airport complex throughout the period. The
quantity of sewage sludge is estimated to be 850,000 gallons
per year today and is projected to increase to 1,820,000
gallons per year by 1985. Demolition materials were not
measured during this study, and an estimate of annual quanti-
ties could not be obtained. The quantity is large, and should
continue to be handled in the existing manner. Industrial
sludges and contaminated oils are presently generated at a
75
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rate in excess of 500,000 gallons per year. Future quantities
are projected to remain at that level. Although this study
did not fully evaluate equipment to handle these special
wastes, a brief commentary is appropriate. The alternative
methods for disposal of industrial wastes are becoming very
limited, thereby increasing disposal costs significantly.
In the future, processing and treatment at the source will
become economically desirable. When this happens, collection
equipment will change. For the present, the industrial tank
trucks and open dump trucks should continue in use.
Selected Collection and Handling Methods
Potential collection and handling methods were identi-
fied in Chapter 5. Each of these methods was subjected to
a technical and economic evaluation based upon present and
future conditions at the airport. The economic evaluation
was based upon unit costs ($ per ton of refuse) and capital
costs. The technical evaluation included construction,
operation, and demonstrated capability of solid waste systems
under airport conditions. Table 8 shows the unit and capital
costs for the collection and handling equipment for which cost
information was obtained. Cost information was not available
for the dry vacuum transport system because complete technical
information on the system is only now becoming available.
Also, the back-end loader vehicle-container system was not
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Table 8
COLLECTION AND HANDLING EQUIPMENT COSTS
,., p> Estimated
Unit cost,UJ Capital cost,1-"' useful life,
Item $ per ton $ years
In-house collection
Rolling cans - 2-cy capacity 5.69 400 10
Stationary compactor (10-ton/day capacity) 1.33 17,500 15
with debris box - 40-cy capacity
Debris box - 20-cy capacity 0.23 1,950 10
Wheel mounted cans (uncompacted) - 4-cy 1.58 775 8
capacity
Wheel mounted cans (compacted) - S-cy capacity 1.11 3,000 10
Collection vehicle
Front-end loader - 30-cy capacity 2.29 31,000 8
Towing tractor - 2-container (compacted) 2.01 3,000 8
capacity
Tilt-frame truck - 30-cy capacity 0.99 23,650 8
Processing
Shredder • 7.5-ton/hr capacity 1.84 21,500 15
Incinerator - 20-ton/day capacity 11.00 500,000 20
Wet pulping - 3,200-lb/hr capacity 5.80 84,700 12
Note: The equipment capacities listed were used to develop the unit costs and might not be the sane
capacities as selected in the final systems.
(1) Includes capital costs amortized at 6 percent interest over the estimated useful life of
equipment and annual operation and maintenance costs for a typical airport system.
(2) Includes equipment cost, shipnent costs to San Francisco, installation costs, and contingencies.
Capital costs based on an ENR of 1900.
Source: Unit costs derived by Metcalf 6 Eddy; capital costs and estimated useful life derived by
Metcalf £ Eddy from data provided by equipment suppliers.
77
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selected for detailed economic analysis because its efficiency
in commercial types of waste systems is known to be extremely
low. Its potential use was in collecting loose hand-thrown
wastes, a system not considered necessary or desirable after
monitoring the airport refuse generation.
The cost data from Table 8 were used initially to
select combinations of collection and handling equipment
that were the most beneficial to the airport solid waste
collection system. The total solid waste management system,
including collection, transfer, processing, and disposal,
did not receive primary consideration during this analysis
of beneficial collection equipment.
Potential Locations for Equipment
The storage containers and processing equipment of the
system should be placed in locations (1) where they will not
interfere with aircraft operations, (2) close to large
quantities of refuse, (3) where they are accessible to
collection vehicles, and (4) where they are accessible to
the tenants delivering in-house collection containers. The
most important criterion concerns aircraft operations.
Airports have much open space, and the potential locations
for storage containers are numerous. Locations where con-
tainers should be placed are listed as follows.
78
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Type of storage container
Location
Stationary compactor with Alongside hangars or terminal
debris box building where power is avail-
able. Exclude from Piers A
through G.
Debris box
Wheel mounted cans
(compacted and uncom-
pacted)
Alongside buildings or fences,
Provide wind protection where
possible. Exclude from Piers
A through G.
Can be used anywhere if kept
outside of aircraft movement
areas.
The potential locations for processing equipment (shred-
ding and wet pulping) are more limited. In reviewing the
use of a shredder at the airport, the most beneficial use
was found in processing bulky wastes. These bulky wastes
are normally concentrated in the air freight area. The wet
pulping system requires the installation of pumps and piping,
and is most beneficial where it serves a single building or
a close grouping of buildings. The potential locations are
listed as follows:
Processing equipment
Shredder and containers
Wet pulping and contain-
ers
Location
Air freight area.
The main terminal garage to
serve all terminals.
United Air Lines maintenance
base.
79
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The final locations of containers will be determined
by the management organization specifying and controlling
solid waste collection systems.
Selected Management Methods
Three management methods for airport solid waste col-
lection systems were identified in Chapter 4. Two of these
methods were selected for evaluation in system development:
full operational control by the airport authority (Method 1),
and control shared between the tenants and the authority
(Method 2). The full tenant control method (Method 3) was
rejected because the quantity and characteristics of the
wastes, and the increasing public concern for the environ-
ment in which solid wastes are generated, require a greater
control by public officials. In addition, only an integrated
management system could yield an economical operation for
all airport tenants.
The present management of the solid waste collection
system has been satisfactory in most areas. Only limited
amounts of paper have been observed blowing, and in no case
has a health hazard existed. Because the existing manage-
ment has been successful in performing the refuse removal
task, a change in management method would require a strong
economic benefit to offset the expense of implementing
changes.
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System Development
Six separate equipment configurations were subjected to an
economic analysis in an attempt to find the most efficient
system. Table 9 shows the equipment evaluated.
From this equipment evaluation two alternative systems were
derived and are presented here. Each system has a potential for
economic benefit to the entire airport complex. Alternative 1
is a modification of the existing collection equipment that would
improve efficiency. Management would exercise a stronger con-
trol over the refuse storage equipment used, but the collection
would be done by the private hauler. Alternative 2 is a complete
change from the existing system. The airport authority would
purchase all storage and handling equipment and would provide
complete refuse collection service.
Before describing each alternative individually, it is im-
portant to identify the guidelines considered essential to the
development of both systems.
1. Flexibility. Because the airport must be constantly
changing and adapting to new tenants, flight equipment,
and passenger service, the solid waste collection sys-
tem must be flexible. In the past, the airport has
undergone major reconstruction on a 5-year cycle.
Solid waste collection systems permanently installed,
with a normal 15-year capital write-off period, may be
obsolete or require relocation after only 5 years.
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Table 9
EQUIPMENT EVALUATED FOR USE
AT SAN FRANCISCO INTERNATIONAL AIRPORT
Configuration
1
2
3
In-house
collection
Wet pulping system
Rolling containers*
Rolling containers*
Storage with
or without
processing
Debris box
Debris box
(stationary com-
pactor)*
Debris box
(stationary com-
pactor)*
Transport
vehicle
Tilt-frame
truck*
Tilt-frame
truck*
Tilt-frame
truck*
Rolling containers*
Rolling containers*
Rolling containers*
Shredding at air
freight area
Wheel mounted cans
(compacted)
Wheel mounted cans
(uncompacted)
Front-end loading
containers*
Towing tractor
Towing tractor
Front-end-
loader truck*
*Equipment presently used.
82
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2. Non-interference with Aircraft Operations. The loading
piers, aprons, taxiways, and runways are reserved for
aircraft movement. The transfer of refuse from a stor-
age container to a collection truck should be prevented
in those areas.
3. In-house Handling. Most major airlines at the airport
have ground support vehicles which handle the materials
entering the solid waste systems. Maximum utilization
of these in-house vehicles to deliver wastes to central
collection containers is desirable.
The two alternatives are described in the following sub-
sections .
Alternative 1
The collection equipment and its approximate locations are
shown on Figure 8. The most significant feature of this system
is the abandoning of 38 front-end loading containers and 60 back-
end loading containers and the consolidation of refuse formerly
stored in those containers into 7 compacted and 5 uncompacted
debris boxes. The locations shown for the containers are only
approximate. Exact locations would depend on power availabil-
ity at compactor locations and generally clear access at all
locations. The removal of all existing front-end and back-end
loading containers is economically feasible since the private
hauler owns them.
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(Tj EJISTIN! ST1TIONMT COIPACTOM
mtnutt tDDiTiONK $t«Tia*»«i
I C * L F In ' I [ T
fllSTIMQ DEIII S
A PROroSEO ADDITIONAL DEMI!
— DOXU
m PIDPQSCD SKXDOIN1 EQUIPIENT
*' II IN STOHA8E DOI
___ SERVICE Alt> lOUHDilT
ISEE Fit. I )
SCHEDULED F0» CONST >U CT I ON
FIG. 8
ALTERNATIVE COLLECTION SYSTEM 1
-------
A shredder has been located in the air cargo area to
reduce the volume of bulky air freight wastes. Again, the
delivery of wastes to the shredder would be an in-house
collection task for each tenant. The shredder is to receive
only wood pallets and bulky nonmetal packing materials. It
would be operated by each tenant as he delivers bulky wastes.
The economic importance of the shredder is small, and if tenants
object to preparing and delivering bulky wastes to this facility
it can be deleted from the system. Three open uncompacted
debris boxes should be substituted if the shredder is not
installed.
The implementation of this system could be accomplished
only through strong control by the airport authority. Most
smaller tenants will not see an immediate benefit, and there-
fore will not react favorably to change. In addition, a
degree of convenience is lost because the storage container
will no longer be outside the door of each tenant. The final
configuration of the total number of containers and container
locations must be worked out with each tenant at the time of
system implementation.
Capital costs and operating personnel requirements are
shown in Table 10. The capital requirements are high while
manpower requirements are low. Capital costs have been
amortized at 6 percent and combined with estimated annual
operation and maintenance costs to form an estimated annual
system cost of $5.20 per ton of refuse collected.
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Table 10
EQUIPMENT AND MANPOWER REQUIREMENTS
AND CAPITAL COSTS FOR
ALTERNATIVE 1
Item
Capital
Amount of Manpower costs
equipment needed for operation $
In-house collection
As practiced by
each tenant
N.I.
N.I.
Storage
Stationary compactor 7^ • '
(with debris box)
Debris box 5
(uncompacted)
Collection vehicle
Tilt-frame truck 2
Processing
Shredder 1
Total
0.5(3) 208,000
(4)
9,000
2 47,000
-- (3) 38,000
2.5 302,000
(1) N.I. - no information.
(2) Compactors already owned and used are capitalized at new cost
here.
(3) One man needed half-time for all equipment maintenance.
(4) Operator of collection vehicle handles debris boxes.
86
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Since the container locations and containers are con-
trolled by the airport, the contract for collection of ref-
use from the airport complex must be administered by the
airport. The contractor would be paid by the airport on the
basis of refuse hauled, and tenant costs would be billed by
the airport as sewage and other utilities are billed now.
With centralized containers and no means of keeping records
on the actual quantity of refuse generated by each tenant,
billings to the tenant should be based on monthly air pas-
sengers and cargo. The weight parameters of pounds per
passenger per day and pounds per ton of cargo, as described
in Chapter 3, are sufficiently accurate to be used for billing
purposes. Smaller waste sources (such as car rental agencies)
not directly involved in air passengers or cargo, would be
charged an equitable flat rate.
The advantages of Alternative 1 over the existing system
are summarized as follows:
• Present collection trips could be reduced from 70
trips per week to 54 trips per week, and total time
consumed in the airport collection could also be
cut approximately by 50 percent (from 51 hours to
24 hours).
• Lower annual costs would result for all tenants
collectively, although each individual tenant might
have a higher or lower cost, depending on present
87
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in-house collection equipment and contract arrange-
ments .
• Potential interference with aircraft movement would
be greatly reduced.
• Security within aircraft operating areas would be
more easily maintained.
• Refuse would be delivered to a limited number of
collection locations by each tenant, thereby uti-
lizing to a greater degree the in-house equipment
(and its flexibility for both refuse hauling and
aircraft operations) of each tennant.
Alternative 2
The collection equipment of Alternative 2, and its approxi-
mate locations, are shown on Figure 9. The most significant
feature of the system is the complete change in containers
and vehicles from the existing system. All existing storage
equipment would be replaced by wheel mounted containers,
and multiple containers would be collected and transported
in a single train by a small powered tractor. The points for
container location shown on Figure 9 represent the center
of refuse collection for the service area shown, not a single
container. The actual number of containers needed to store
and transport the refuse is shown in Table 11, along with the
total system cost.
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PIOPOSED TRANSFER STATION
SCHEDULED F0« COKSIIUC T I ON
SFDVICE >•[> lOUNDtir (SEE FIB.I)
IOUIES 10 IE USED IN
IOKINI COHTOINEIS TO THE
TMNSFCI STIIT ION
<00 0 iOO BOO 1700
SCAL( IH F[[ T
FIG. 9
ALTERNATIVE COLLECTION SYSTEK 2
89
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Table 11
EQUIPMENT AND MANPOWER REQUIREMENTS
AND CAPITAL COSTS FOR
ALTERNATIVE 2
Item
Capital
Amount of Manpower costs
equipment needed fo'r operation $
•In-house collection
As practiced by
each tenant
N.I.
N.I.
N.I.
Storage
Wheel mounted cans
(uncompacted)
Wheel mounted cans
(compacted)
Collection vehicle
Towing tractor
Transfer
48
5
.. (2)
.. (2)
(1) N.I. - no information.
(2) Operator of vehicle handles wheel mounted cans.
36,000
38,000
12,000
Station 1
Truck and trailer 1
Total
1
1
5
32,000
46,000
164,000
90
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Since the wheel mounted containers considered here are
not constructed for operating at speeds over 15 to 20 miles
per hour, it is not feasible to transport the individual
containers long distances to a disposal site. Therefore, a
transfer station has been located on the airport at which
each small container can be emptied into a single larger
trailer for movement to the disposal site. The station has
the capacity to handle all present solid wastes, and would
be capable of handling all wastes generated through 1985.
The location of the station as shown on Figure 9 is approxi-
mate. If moved to another place, it should be located so that
access for the small wheel mounted containers is good, and
also so that the large transfer trailer and tractor have good
access to the freeway.
The implementation of this system would be accomplished
under full operational control by the airport. The airport
utility staff would be expanded to provide the container
pickup service, operate the transfer station, and operate
the transfer truck between the airport and the disposal site.
The number of people needed to operate the system is shown
in Table 11. A small garage and equipment storage space would
be needed in the same location as the transfer station. As
in Alternative 1, the in-house collection system of the tenants
would be used to the maximum degree possible in Alternative 2.
The wheel mounted containers would be grouped in the loca-
tions shown, and each tenant would use in-house collection
91
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to deliver solid wastes to that location. The airport col-
lection crew would then come to the collection point on a
preset schedule, attach all filled containers to the powered
tractor and, following the routes shown on Figure 9, deliver
the containers to the transfer station.
The capital cost is shown in Table 11, Capital costs
are low while manpower requirements are high. Capital costs
have been amortized at 6 percent and combined with estimated
annual operation and maintenance costs to form an estimated
annual system cost of $5.60 per ton of refuse collected and
delivered to a transfer vehicle.
The billing of tenants to cover the cost of installing
and operating the solid waste collection system would be done
by the airport. Each tenant should be billed in relation to
the wastes generated. As described in Alternative 1, this could
be done on the basis of air passengers and cargo handled during
the billing period.
The advantages of Alternative 2 over the existing system
are summarized as follows:
• Solid wastes technology is presently evolving at a
very rapid rate. More efficient processes may soon
be developed. This alternative would be most flex-
ible for adapting to future change.
• Through an integrated management system operated
exclusively by the airport, tenants would collectively
92
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benefit from lower annual costs and also from future
changes in technology that might require a large
amount of investment to update the system.
• Although the collection time and number of pickups
would be nearly equivalent to the existing system,
airport security would be increased under Alter-
native 2 because airport personnel would be oper-
ating on collection routes. Interference with
aircraft operations would also be minimized because
the towing tractors and containers are approximately
the same size as baggage handling equipment widely
used around aircraft.
Cost Analysis
The capital and operation and maintenance costs for each
alternative collection system were developed in preceding
sections. These values were then compared to the present
system costs in an attempt to establish economic benefit by
implementing system modifications.
The present system costs were derived from data supplied
by the private hauler. To verify those costs, each tenant
was requested to provide the total cost of refuse collection
for July and August 1971. The results of summing tenant data
verified the billings supplied by the hauler. The annual
costs were divided by the total annual weight of refuse collected
93
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(total weekly weight was measured during this study) to obtain
a unit cost of collection. The unit cost of the present system
was computed to be $16.10 per ton of refuse collected. This
is a cost for refuse collection (including a lease charge for
most containers on the airport), transportation, and disposal.
It cannot be compared directly with costs for Alternatives 1
and 2 without identifying the transportation and disposal costs
The private hauler reported a disposal fee of $3.48 per
ton. Assuming a transportation charge of $4.00 per ton (a
high figure to give the present system the greatest advantage),
the total disposal and transportation cost to be deducted from
the present system cost was $7.48 per ton. The estimated
collection cost under the present system, then, is $8.63 per
ton (say $8.60).
A comparison of the unit costs is shown in the following
tabulation:
Unit cost,
'ton collected
Alternative 1 5.20
Alternative 2 5.60
Present system 8.60
It can be seen that a potential benefit of $3.40 per ton exists
for Alternative 1 over the present system, and a benefit of
$3.00 per ton exists for Alternative 2 over the present system.
94
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At the present refuse generation rate of 14,900 tons per year,
Alternative 1 has an annual benefit of $51,000 per year. Ex-
pressed as a percentage of present costs, this would be a 21
percent reduction in costs. Projecting refuse quantities and
cost to 1985, Alternative 1 would be handling 34,900 tons
per year at $3.40 per ton less, or a benefit by 1985 of $120,000
per year.
The annual costs and cost savings for two periods (1971
and 1985) under the existing system, Alternative 1, and
Alternative 2 are shown in the following tabulation.
For 1971 refuse For 1985 refuse
quantity(l) quantityf2)
Existing system
Annual cost $128,700 $302,000
Alternative 1
Annual cost 77,700 182,000
Annual savings 51,000 120,000
compared with
existing system
costs
Alternative 2
Annual cost 83,200 195,000
Annual savings 45,500 107,000
compared with
existing system
costs
(1) 14,900 tons per year for 1971
(2) 34,900 tons per year for 1985
95
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Conclusion
A phased schedule of improvements is not presented here
because such a schedule is difficult to develop and coordi-
nate under the present conditions of fragmented control. The
study scope was not broad enough to include an evaluation of
each tenant, his waste generation, and his improvements in
collection so that individual benefit is achieved.
The airport complex cost benefits that could be achieved
in either system are large enough to warrant a serious con-
sideration of modifications to the existing collection system.
The primary consideration in undertaking system modifications
is not entirely one of economics or available capital, but
rather strong airport control of solid waste management so
that a combination of unimpeded operations, strong security,
and economy is obtained. As an example, under present
management control, the obvious benefits of installing a large,
efficient compaction unit cannot be realized if a tenant does
not want it. Yet, the benefit is there. The airport should
take action with respect to both management and equipment.
This can be accomplished under either Alternative 1 or 2.
The changes in equipment that have shown a potential for
benefit are related to container size and location. The
equipment with the greatest benefit potential for the
collection system has been identified in Alternatives 1 and 2.
The final determination of the alternative to be used should
96
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be based upon the degree of operational control the airport
wishes to maintain over refuse collection. With either
alternative, however, the airport authority should play a
stronger future role in controlling its solid waste system.
97
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Appendix A
WEIGHING AND SAMPLING TECHNIQUES
Weighing Method
The weighing program was planned on the basis of the
existing collection system. The objective was to determine
the total weight of waste generated and the quantity gen-
erated by each of four major types of airport facilities.
Therefore, the program included weighing every refuse
truck serving the airport. Since the present collection
routes vary with the quantity of refuse generated every day,
close coordination with the private hauler was maintained.
A semi-permanent weighing station was set up at a con-
venient location for the haulers, and all refuse trucks
were weighed upon entering and again upon leaving the air-
port premises. Since most refuse collection takes place at
night, the working hours of the weighing team were from
10:30 p.m. to 9:00 a.m. Collections made during other
times of the day, such as those from debris boxes and
special accounts, were weighed individually upon
notification by the haulers.
Some trucks collected only from one of the four major
types of airport facilities, and for these trucks it was
sufficient to record their incoming and outgoing weights,
98
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and the source of their wastes. Other trucks, however,
collected from several different types of facilities. To
determine the portion of their loads attributable to each
type, it was necessary to follow them with portable scales
and weigh them after each facility stop. Accordingly, two
two-man teams were used to accomplish the entire weighing
program--one team at the semi-permanent weigh station and
one team following individual trucks to identify their
refuse collection routes and weigh them at intermediate
collection points.
The weighing program was accomplished in a one-week
period during the summer of 1971. The results were
summarized and are shown in Chapter 3 (Table 3).
The weighing for the aircraft wastes was conducted by
direct measurement of wastes removed from the flight by
the service crew. Since it was not practical to obtain
samples from all airlines, United Air Lines, Pan Am, TWA,
and Western Airlines were selected as typical carriers to
be sampled. The factors that determine the quantity and the
composition of aircraft passenger wastes are considered to
be: (1) the number of passengers, (2) time of flight, (3)
distance of flight, (4) number of meals served on board, and
(5) type of aircraft. In order to facilitate identification
of these factors, each sample was weighed and identified by
99
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flight number. The results are presented in Chapter 3
(Table 4).
Sampling Methods
The sampling program was set up so that statistically
sound data would be obtained within the funding limitations
of the study. Based upon previous sampling experience, 10
samples were to be taken from each of the four major sources
and then subjected to physical and chemical analyses. This
was an optimum number which was modified later to suit the
actual airport conditions. No attempt was made to identify
seasonal variation on samples because the composition of
refuse from airports was not known to vary with the season.
The sampling procedures generally followed the recom-
mended procedures of the APWA. The only modifications in-
volved the quantity sampled and the sampling location. The
quantity sampled was to be less than 500 pounds, and the
sampling location was directly at the source instead of from
the collection truck. The specific sampling procedures used
at each source are described in the following paragraphs.
1. Passenger Terminals. The refuse storage rooms of
the Central and South terminals were used as sampling
rooms. Refuse from the Central and South terminals
100
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was considered as being representative of the entire
passenger terminal area, and composite samples were
prepared of 60 percent Central Terminal wastes and
40 percent South Terminal wastes.
Within the Central Terminal sampling room, the space
was divided into four quadrants with equal numbers
of refuse containers in each quadrant. To minimize
the prejudgment factor involved in selecting the
wastes, each sample was restricted to one quadrant
of the room without regard to the composition of the
refuse in that quadrant. From the Central Terminal
room, approximately 150 pounds of refuse were taken
for each sample. This quantity was then separated
into nine standard components, and the weight of
each was recorded. The organic components were then
extracted, mixed, and bagged for temporary storage.
The procedure was repeated in the South Terminal
sampling room, except that approximately 100 pounds
were taken from one quadrant of the room for each
sample. After separation into the nine components
and subsequent weighing, the organic components
were extracted, mixed, bagged, and transported to
the Central Terminal sampling room for mixture with
101
-------
the organics bagged there. After thorough mixing,
the organics were quartered, and about 20 pounds
were extracted from one quadrant and shredded. The
shredded sample was then placed in sealed containers
and taken to the laboratory for chemical analysis.
The sampling schedule for the passenger terminals
was arranged to cover different collection trips
during a 2-week sampling period from July 16 through
July 29. Ten composite samples were taken, and the
results are shown in Table A-l, which lists the
weight of each component in each sample and the per-
cent by weight of each component. The mean value
of each component was then computed to present a
representative pattern of component distribution.
Variance and standard deviation were calculated to
determine the dispersion of the sampled data.
Since the sampling program was designed to obtain
representative results through random sampling,
the distribution of sampled data was assumed to be
normal. With this assumption, the confidence ranges
of the data that would result in a 95 percent con-
fidence range of normal distribution using 10 sam-
ples were identified and are shown in Table A-2.
102
-------
Table A-l
SAMPLING DATA - QUANTITIES OF SOLID WASTES FROM
PASSENGER TERMINALS BY COMPONENT
San Francisco International Airport, July 1971
^^^^Jample no. 5
^^^*^ du te
Component ^^^v^
Paper 5 paper
products
Plastics
Food wastes
Wood S wood
products
Trimmings
Metal 6 cans
Glass, stone
S ceramics
Dirt S demolition
materials
Miscellaneous
Total
Pounds
1 2
7/15 7/16
238 201
17 19
43 23
9 0
0 0
53 21
49 9
15 11
28 10
452 294
3
7/19
188
13
21
11
0
14
11
8
13
279
4
7/2.'
20o
10
11
S
5
15
5
3
3
266
5
7/21
205
a
15
7
1
7
0
4
14
259
6
7/2:
173
13
10
21
0
18
10
3
7
255
7
7/23
20:
7
11
15
0
8
S
4
9
261
8
7/26
175
19
14
7
0
21
26
5
10
277
9
1/21
210
13
9
5
0
14
9
2
5
267
10
7/2S
193
30
5
4
0
14
7
3
6
262
Percent
Paper 3 paper
products
Plastics
Pood wastes
Wood 8, wood
products
Trimmings
Metal 5 cans
Glass, stone,
$ ceramics
Dirt 5 demolition
materials
Miscellaneous
Tot.lt"
53 68
4 6
10 8
2 0
0 0
12 7
11 3
3 4
6 __3
100 100
67
5
g
4
0
S
4
3
.5
100
78
4
4
3
2
6
2
1
1
100
79
2
6
3
0C
X
0
2
_J
100
68
5
4
8
" 0
7
4
1
3
100
77
3
4
6
0
3
2
2
3
100
63
7
5
3
0
8
9
2
(
4
100
79
5
3
2
0
S
3
1
_ 2
100
74
12
2
2
0
S
3
1
_2
100
Total
1,991
147
162
87
6
185
131
58
105
2,872
Mean
value
71
5
5
3
0C2)
6
4
2
3
100
(1) Figures may not add due to rounding.
(2) Less than 0.5 percent.
103
-------
Table A-2
SAMPLING DATA - CONFIDENCE RANGE ON DATA
FROM PASSENGER TERMINALS BY COMPONENT
San Francisco International Airport, July 1971
Component
Paper 5 paper
products
Plastics
Food wastes
Wood (, wood
products
Trimmings
Metal 5 cans
Glass, stone,
6 ceramics
Dirt 5 demolition
materials
Miscellaneous
Mean
value Variance
(*) 0)
70.6
5.3
5.3
3.3
0.2
6.1
4.1
1.8
3.3
71.2
7.0
5.5
S.S
0.3
6.6
11.4
1.1
2.6
Standard
deviation
(*)
8.4
2.6
2.3
2.3
O.S
2.5
3.3
1.0
1.6
Number of
samples
taken
10
10
10
10
10
10
10
10
10
Confidence
(*)
95
95
95
95
95
95
95
95
95
Confidence
From
65.4
3.6
3.8
3.8
0
4.4
2.0
1.2
2.3
range (t)
To
75.8
7.0
6.8
6.8
l.S
6.8
6.2
2.4
4.3
-------
These ranges are commonly referred to as the result
range and are widely used in engineering reports.
The statistical method used generally follows stan-
dard statistical procedures. The formulas are:
n - i
where
S = standard deviation
y = value for each discrete sample, expressed
in percent by weight
y = mean value for all samples taken, expressed
in percent by weight
n = total number of samples taken
and
where
P (1 Z- ll 6) - a
I— = the random variable associated with
sample mean, or Z— = — — y
6 = positive scalar which is equal to h times
of the standard error of sample mean,
j==^- . In the case of 95 percent confidence
range, h=1.96.
a = probability of error for the desired con-
fidence range. For 95 percent confidence,
a is equal to 0.05.
105
-------
2. Air Freight Area. The refuse generation from the
air freight area is spread over a wide cargo area,
with no single source being representative of all
sources. Accordingly, composite samples included
the refuse generated by all tenants. Depending
upon availability of refuse from each tenant at the
time of collection for sampling, each composite
sample contained roughly equal proportions of refuse
from each tenant. General procedures for quartering,
separating, and weighing the refuse were the same
as described for the passenger terminals. The
sampling was completed from July 16 through July 29.
Ten composite samples of approximately 250 pounds
each were analyzed. Statistical testing was per-
formed as described for the passenger terminals.
The results are shown in Tables A-3 and A-4.
3. Aircraft Service Centers. Service center wastes
consist of wastes from flight kitchens, aircraft,
and service buildings.
Sampling was done from two sources within the
service center, with 5 samples from service build-
ings and 27 samples from aircraft. Of the 27
aircraft samples, 11 were taken from aircraft with
106
-------
Table A-3
SAMPLING DATA - QUANTITIES OF SOLID WASTES FROM
AIR FREIGHT AREA BY COMPONENT
San Francisco International Airport, July 1971
^"^^^Sample no. 5
Component ^^"-^^
Paper 5 paper
products
Plastics
Food wastes
Wood 6 wood
products
Trimmings
Metal 6 cans
Glass, stone,
& ceramics
Dirt 6 demolition
materials
Miscellaneous
Total
Pounds
1
7/15
182
21
9
15
0
12
4
11
13
267
2
7/16
140
11
S
13
8
15
20
41
25
278
3
7/19
162
25
6
19
15
10
5
7
4
253
4
7/20
85
29
24
31
15
18
7
18
48
275
5
7/21
82
17
11
58
7
56
9
4
28
272
6
7/22
122
46
6
36
20
28
8
12
16
294
7
7/23
152
26
3
40
0
18
7
5
4
265
8
7/26
81
18
12
65
S
42
10
4
24
261
9
7/27
131
60
7
84
1
3
7
20
1
314
10
7/28
102
25
3
109
0
8
12
1
2
262
Percent
Paper 6 paper
products
Plastics
Food wastes
Wood 5 wood
products
Trimmings
Metal 6 cans
Glass, stone.
6 ceramics
Dirt fi demolition
materials
Miscellaneous
Total'1'
68
8
3
6
0
5
2
4
5
100
SO
4
2
5
3
S
7
IS
9
100
64
10
2
8
6
4
2
3
2
100
31
11
9
11
5
7
3
7
18
100
30
6
4
21
3
21
3
2
10
100
42
16
2
12
7
10
3
4
S
100
61
10
1
15
0
7
3
2
2
100
31
7
5
25
2
16
4
2
9
100
42
19
2
27
0(
1
2
6
0(
100
39
10
1
42
2' 0
3
5
0(2)
2> 1
100
Total
1,249
278
86
470
71
210
89
123
165
2,741
Mean
value
46
10
3
17
' 3
8
3
4
6_
100
(1J Figures may not add due to rounding.
(2) Less than 0.5 percent.
107
-------
Table A-4
SAMPLING DATA - CONFIDENCE RANGE ON DATA
FROM AIR FREIGHT AREA BY COMPONENT
San Francisco International Airport, July 1971
Component
Paper 5 paper
products
Plastics
Food wastes
Wood 6 wood
products
Trimmings
Metal 6 cans
Glass, stone,
Q ceramics
Dirt 5 demolition
materials
Miscellaneous
Mean
value
W
45. 7
10.0
3.2
17.1
2.6
7.7
3. 3
4.4
6.0
Variance
0)
206.9
19.8
5.2
127.8
7.0
37.3
2.8
17.5
30.1
Standard
deviation
(t)
14.4
4.4
2.3
11.3
2.6
6.1
1. 7
4.2
5.5
Number of
samples
taken
10
10
10
10
10
10
10
10
10
Confidence
(*)
95
95
95
95
95
95
95
95
95
Confidence
From
36.8
7.3
1.2
10.1
1.0
3.9
2.3
1.8
2.6
range (I)
To
54.6
12.7
5.2
24.1
4.2
11.5
4.4
7.0
9.4
108
-------
mean service wastes and 16 from aircraft without
meal service wastes. The combined daily weights
are summarized in Table A-5. The sampling, quarter-
ing, and weighing was done as described for passen-
ger terminals. However, the statistical procedures
for testing the data were modified because three
separate sources of waste were measured at the
service center during sampling. The data from each
source were tested statistically, and the results
are summarized in Table A-6. The results of statis-
tical testing for each service center source are
shown in Tables A-7 through A-9. The data were
accumulated and presented in this way because it
was felt that waste generation from all aircraft
should be cataloged to the highest degree possible.
After the data were accumulated, it could be seen
that a breakdown of refuse composition by each
source was an additional step not necessary for
identifying planning criteria. General composite
refuse component values for an entire service center
are meaningful for planning equipment systems for
an entire airport complex. Therefore, the general
composite values are summarized and a mean service
center value for each component is presented.
The basic weight data from each source are also
109
-------
Table A-5
SAMPLING DATA - QUANTITIES OF SOLID WASTES FROM
AIRCRAFT SERVICE CENTER BY COMPONENT
San Francisco International Airport, August-December 1971
^^-^Sample no. &
^"N>N^ date
Component ^^v_
Paper 6 paper
products
Plastics
Food wastes
Wood 8 wood
products
Trimmings
Metal 8 cans
Glass, stone,
S ceramics
Dirt S demolition
materials
Miscellaneous
Total
Pounds
1
8/30
59
49
198
0
0
38
9
3
30
386
2
3/31
83
38
189
0
0
40
14
2
3
369
3
9/1
61
44
178
0
0
93
70
2
4
452
4
9/:
59
T
3
0
0
1
1
3
0
69
S
9/3
38
4
0
0
0
1
0
2
1
46
6
9/7
26
9
27
0
0
12
3
0
1
78
7
9/13
58
32
139
0
0
S3
5
1
1
289
8
9/14
126
50
192
0
0
60
27
4
6
465
9
9/15
115
34
42
3
0
24
22
0
9
249
10
9/16
79
11
17
0
0
15
10
1
2
135
11
i:/i
L40
18
0
14
0
25
42
16
3
258
12
i:/:
256
40
Z
80
0
59
27
9
47
520
13
i:/8
353
20
22
34
0
35
14
6
46
530
Percent
Paper S paper
products
Plastics
Food wastes
Wood 8 wood
products
Trimmings
Metal 6 cans
Glass, stone,
8 ceramics
Dirt 8 demolition
materials
Miscellaneous
Total'2'
IS
13
51
0
0
10
2
1
8
100
23
10
51
0
0
11
4
0
1
100
14
10
40
0
0
20
15
0
1
100
85
3
S
0
0
2
1
4
0
100
83
9
0
0
0
1
0
5
2
100
34
12
35
0
0
IS
3
0
1
100
20
11
48
0
0
18
2
0
1
100
27
11
41
0
0
13
6
1
1
100
46
14
17
1
0
10
9
' 0
4
100
58
8
13
0
0
11
7
1
2
100
54
7
0
6
0
16
6
1
10
100
49
8
0
16
0
6
5
3
9
100
66
4
4
6
0
7
3
1
9
100
Total
1 , 4 5 3
351
1,00?
131
0
456
244
4S
153
3,846
Mean ,,..
value(i)
32
10
34
2
0
12
4
1
5
100
Note: Composite samples 1, 2, 3, and 8 are the waste samples from meal-served flights; composite samples
4, S, 6, 7, 9, and 10 are the waste samples from non-meal flights; and composite samples 11, 12,
and 13 are the waste samples from service buildings.
(1) Mean values were computed by using the method shown in Table A-6.
(2) Figures nay not add due to rounding.
110
-------
Table A-6
SAMPLING DATA - PERCENT DISTRIBUTION OF WASTES
COMPRISING AIRCRAFT SERVICE CENTER WASTES BY COMPONENT
San Francisco International Airport, August-December 1971
Aircraft wastes
Mean of 11
samples of aircraft
Component meal service wastes
Paper 6 paper
products
Plastics
Food wastes
Wood 5 wood
products
Trimmings
Metal 5 cans
Glass, stone,
5 ceramics
Dirt 5 demolition
materials
Miscellaneous
Total
20
12
46
0
0
13
4
0
3
100
.6
.0
.3
.0
.0
.6
.5
.0
Mean of 16
samples of aircraft Composite Service
wastes excluding aircraft,.... building
meal service wastes wastes *• ' wastes
84
S
2
0
0
1
0
4
1
100
.0
.S
.8
.4
.6
.6
.0
.0
23.8
11.7
44.1
0
0
12.4
3.8
0.8
3.4
100.0
57
6
1
9
0
10
4
1
9
100
.1
.0
.8
.9
.4
.4
.4
.0
.0
Composite
service
center /2\
wastes l '
32
10
33
2
0
11
4
0
4
100
.1
.3
.6
.S
.9
.0
.9
.7
.0
(1) Composite aircraft meal service wastes are composed of 9S percent meal service wastes nnd
S percent other aircraft wastes (excludine meal service wastes). The percent distribution
was obtained from weighing data.
(2) Composite service center wastes are composed of 7S percent composite aircraft wastes and 2S
percent service building wastes. The percent distribution was obtained from weighing data.
Ill
-------
Table A-7
SAMPLING DATA - CONFIDENCE RANGE ON DATA FOR
MEAL SERVICE WASTES BY COMPONENT
San Francisco International Airport, August-September 1971
Component
Paper 5 paper
products
Plastics
Food wastes
Wood 5 wood
products
Trimmings
Metal fi cans
Glass, stone,
6 ceramics
Dirt 5 demolition
materials
Miscellaneous
Mean Standard
value Variance deviation
cn m (»)
20.6
12.0
46.3
0
0
13.0
4.0
0.6
3.5
58.4
16.6
77.5
0
0
19.4
26.8
0.2
17.8
7.7
4.1
8.8
0
0
4.4
5.2
0.4
4.2
Number of
samples
taken
11
11
11
11
11
11
11
11
11
Confidence
(*)
95
95
95
95
95
95
95
95
95
Confidence
From
16.1
9.6
41.1
0
0
10.4
0.9
0.3
1.0
range (I)
To
25.1
14.4
51. S
0
0
15.6
7.1
0.9
6.0
Table A-8
SAMPLING DATA - CONFIDENCE RANGE ON DATA FOR
AIRCRAFT WASTES (EXCLUDING MEAL SERVICE WASTES) BY COMPONENT
San Francisco International Airport, August-September 1971
Component
Paper § paper
products
Plastics
Food wastes
Wood 8 wood
products
Trimmings
Metal $ cans
Glass, stone,
6 ceramics
Dirt 5 demolition
materials
Miscellaneous
Mean
value
(*)
82.9
6.1
1.9
0
0
1.5
0.4
5.8
1.4
Variance
W
69.0
34.2
22.1
0
0
8.9
1.2
19.5
4.6
Standard
deviation
(*)
8.3
5.8
4.7
0
0
3.0
1.1
4.4
2.2
Number of
samples
taken
16
16
16
16
16
16
16
16
16
Confidence
(*)
95
95
95
95
95
95
95
95
95
Confidence
From
78.8
3.3
0
0
0
0
0
3.6
0.3
range (%)
To
87.0
8.9
4.2
0
0
3.0
0.9
8.0
2.5
112
-------
Table A-9
SAMPLING DATA - CONFIDENCE RANGE ON DATA FOR
SERVICE BUILDINGS BY COMPONENT
San Francisco International Airport, December 1971
Component
Paper 5 paper
products
Plastics
Food wastes
Wood 5 wood
products
Trimmings
Metal 5 cans
Glass, stone,
6 ceramics
Mean
value Variance
cn m
57.1
6.0
1.8
9.9
0
10.4
4.4
54.5
9.1
6.1
17.5
0
18.2
3.2
Standard
deviation
C%)
7.4
3.0
2.S
4.2
0
4.3
1.8
Number of
samples
taken
5
5
5
5
5
5
5
Confidence
(t)
95
95
95
95
95
95
95
Confidence
From
50.6
3.4
0
6.2
0
6.6
2.8
range (I)
To
63.6
8.6
4.0
13.6
0
14.2
6.0
Dirt 6 demolition 1.4 0.3 0.6 5
materials
Miscellaneous 9.0 1.3 1.2 5
95
95
0.9 1.9
7.9 10.1
113
-------
presented, but only as a summary of daily values
for each individual weighing.
4. Aircraft Maintenance Base. Five samples were taken
from the United Air Lines maintenance base. These
samples were taken from refuse generated in the
shops and administrative areas of the base. Addi-
tional wastes are generated at the base which are
not picked up and delivered to the compacted con-
tainer at which sampling was done. Examples of
wastes not sampled include industrial sludges and
salvaged metals. Such wastes are not normally
considered a part of the waste stream, and it is
believed that the wastes sampled do represent those
normally handled in a solid waste collection system.
Approximately 100 containers are used in the in-
house system to collect refuse from all of the
shops. A sampling technique of taking 50 pounds
of refuse from every tenth refuse container was
used to produce a composite sample. The sorting
and weighing was done from the in-house containers
on-site at the compactor. Sampling was completed
during the week of August 16 through August 20.
The results are shown in Table A-10. Actual sample
111
-------
Table A-10
SAMPLING DATA - QUANTITIES OF SOLID WASTES FROM
AIRCRAFT MAINTENANCE BASE BY COMPONENT
San Francisco International Airport, August 1971
^^v^S ample no. §
\^ate
Component ^\^.
Paper 5 paper
products
Plastics
Food wastes
Wood 5 wood
products
Trimmings
Metal 5 cans
Glass, stone,
5 ceramics
Dirt 6 demolition
materials
Miscellaneous
Total
Pounds
1
3/16
142
22
30
1
0
23
54
4
11
287
2
8/17
195
40
39
10
0
17
25
1
12
339
3
8/1S
158
31
87
15
0
30
20
3
17
361
4
8/19
202
22
59
35
0
13
27
3
4
365
5
8/20
328
91
85
S3
0
31
62
11
25
686
Percent
Paper 6 paper
products
Plastics
Food wastes
Wood 5 wood
products
Trimmings
Metal 5 cans
Glass, stone,
6 ceramics
Dirt 5 demolition
materials
Miscellaneous
Total'"
50
8
10
0
0
a
19
1
4
100
58
12
12
(2) 3
0
s
7
0
4
100
44
9
24
4
0
8
6
(2) !
5
100
56
6
16
10
0
4
7
1
1
100
49
13
12
8
d
5
9
2
4
100
Total
1,025
206
300
114
0
114
188
22
69
2,038
Mean
value
51
10
IS
5
0
6
10
1
3
100
(1) Figures may not add due to rounding.
(2) Less than 0.5 percent.
115
-------
size for 5 samples ranged from 287 pounds to 686
pounds. This wide variation in the quantity sampled
was caused by a variable number of in-house con-
tainers emptied during each day. Only 5 samples
were taken since the source of the refuse was well
known and extreme variations in composition were not
expected. Procedures for quartering, separating,
and weighing were similar to those described for the
passenger terminals. Statistical testing followed
the procedure described for passenger terminals.
The results of statistical analysis are shown in
Table A-ll.
In every separated and categorized sample, a 20-pound
composite mixture of the organic portions of the sample was
set aside and stored in plastic bags for additional analyses.
This sample was transported from the separation stations to
the field laboratory for additional processing, usually
within 2 hours of obtaining a sample. This refuse was then
passed through a standard garden shredder (Sears Model 28526N)
The shredded wastes were then mixed and quartered down to a
quantity that fit into a 1-gallon can. These cans were then
sealed with plastic lids and stored for chemical testing.
The final sample which was tested weighed approximately 50
grams. All testing was completed within 24 hours of taking
the sample.
116
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Table A-ll
SAMPLING DATA - CONFIDENCE RANGE ON DATA
FROM AIRCRAFT MAINTENANCE BASE BY COMPONENT
San Francisco International Airport, August 1971
Component
Paper 6 paper
products
Plastics
Food wastes
Wood 5 wood
wastes
Trimmings
Metal § cans
Glass, stone,
5 ceramics
Mean Standard
value Variance deviation
w (*) m
50
9
14
5
0
5
9
.9
.5
.9
.0
.8
.6
29
8
30
13
0
4
24
.6
.8
.9
.7
.4
.2
5.5
3.0
5.6
3.7
0
2.1
4.9
Number of
samples
taken
S
5
5
5
S
5
5
Confidence
(*)
95
95
95
95
95
95
95
Confidence
From
46.1
6.9
10.0
1.8
0
4.0
5.3
range (I)
To
55.
12.
19.
8.
0
7.
13.
7
1
2
2
8
9
Dirt 6 demolition 0.9 0.22 O.S S
materials
Miscellaneous 3.4 1.4 1.2 5
95
95
0.5 1.3
2.3 4.5
117
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Moisture content and volatile solids and ash were the
parameters selected for chemical tests. The results of these
tests were thought to be the most significant for evaluating
processing methods that would benefit the refuse collection
and transportation system. The results of these tests can
be used to estimate the Btu (British thermal unit) content
of refuse and to estimate the residue remaining after burning.
The laboratory procedures in Standard Methods for the
Examination of Water and Wastewater, 12th Edition were used to
conduct the moisture content and volatile solids and ash tests.
For each sample, three identical tests were run using 50 grams
for each test. The mean of the test results was then expressed
as the daily sample value. All individual daily results for all
samples are presented in Table A-12. It should be noted that the
average values for the service center wastes are not necessarily
equal to the average value of 15 samples. The composite weight-
ing method used to derive the average is similar to the method
used for developing averages for physical classification for
service centers. A summary table of average values is presented
in Chapter 3 (Table 6).
The values shown in Table A-12 represent moisture con-
tent and volatile solids and ash for the organic portion of
wastes only. The data were accumulated in this way because
118
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Table A-12
SAMPLING DATA - CHEMICAL CHARACTERISTICS OF
ORGANIC SOLID WASTES BY SOURCE AND SAMPLE NUMBER
San Francisco International Airport, July-November 1971
Percent (mean values)
Source
Passenger
terminals
Air freight
area
Aircraft
service,,.
centers'- '
Aircraft
maintenance
base
Sample
number
1
2
3
4
5
6
7
8
9
10
Average
1
2
3
4
5
6
7
8
9
10
Average
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Average
1
2
3
4
5
Average
Sampling
date
7/15/71
7/16/71
7/19/71
7/20/71
7/21/71
7/22/71
7/23/71
7/26/71
7/27/71
7/23/71
7/15/71
7/16/71
7/19/71
7/20/71
7/21/71
7/22/71
7/23/71
7/26/71
7/27/71
7/28/71
8/50/71
8/31/71
9/1/71
9/2/71
9/3/71
9/7/71
9/13/71
9/14/71
9/15/71
9/16/71
12/1/71
12/2/71
12/3/71
12/7/71
.,.12/8/71
(2)
8/16/71
8/17/71
8/18/71
8/19/71
8/20/71
Moisture
content
22
17
25
11
11
16
21
42
44
42
25
9
7
9
28
20
12
24
37
22
34
20
18
37
49
37
5
50
41
29
47
31
7
18
48
5
5
28
9
8
31
32
16
16
.6
.8
.0
. 1
.0
.6
. 3
.6
. 7
. 8
. 4
.2
.5
.3
. 1
. 1
. 7
.3
.3
.8
. 1
.5
.1
. 4
.1
. 4
.6
.5
. 4
. 7
.1
.1
.0
.2
.6
. 4
. 7
.5
.9
.6
.4
.5
.3
.5
Volatile
solids
t
94
93
91
89
80
87
93
96
90
92
90
95
76
95
95
94
86
78
92
92
88
89
92
91
91
95
98
93
89
96
96
90
90
92
87
89
96
91
93
94
91
95
93
93
.1
.3
.6
. 5
.4
. 1
.6
. 3
.3
.6
.9
.4
.0
. 7
. 4
.6
.3
.2
.9
. 7
.1
.5
.8
. 3
.5
. 7
. 1
.0
. 3
.3
.2
.3
.2
.5
. 3
.5
.8
.9
.'3
.1
.1
. 7
. 7
.6
Ash
5.
6.
8.
10.
19.
12.
6.
3.
9.
7.
9.
4.
24.
4.
4.
S.
13.
21.
7.
7.
11.
10.
7.
8.
8.
4.
5.
7.
10.
3.
3.
9.
9.
7.
12.
10.
3.
8.
6.
5.
8.
4.
6.
6.
9
7
4
5
6
9
4
7
7
4
1
6
0
3
6
4
7
8
1
3
9
S
2
7
5
3
e
0
7
7
8
7
8
5
7
S
2
1
7
9
9
3
3
4
(1) Composite samples 1, 2, 5, and 8 are the waste samples from
meal-served flights; composite samples 4, 5, 6, 7, 9, and 10
are the waste samples from non-meal flights; and composite
samples 11 to IS are the waste samples from service buildings.
(2) Average values were computed by using method similar to that
in Table A-6.
119
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inorganic portions of the waste could not be processed
through the shredder, requiring separation before processing.
The sampling results have been carried forward and presented
as separate data. In evaluating processing systems where
both organic and inorganic materials are mixed, the inorganic
residue must be included for sizing equipment. The effect
on the chemical testing results if inorganics are included
would be to lower the percentage of volatile solids, increase
the percentage of ash, and leave unchanged the percentage of
moisture content. This transformation of data can be done
on the basis of the weighted quantity of inorganics in the
sample.
120
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Appendix B
SAMPLE OF SURVEY QUESTIONNAIRE
Airport Solid Viastc Activity Questionnaire
Name of Ai rnort:
Please fill oui all the blanks to the best of your knowledge. If the- question asked is not
applicable to your operations, indicate by writing "Not Used (.Ml)." If there is no informa-
tion available to you, please write "No I n foria.it i on (Ml)."
In format i on on Your Airport Opev.it ions
Please provide the following dat;i for the last fiscal or calendar year.
On ii Off
1. Combined Total .Vunber of Arrivals and Departures for:
A. Passenger Flights
B. Air Freight Rights
C, Commitcr No/i-Mc.tl Mights (under 500 aiilcs)
1), General Aviation Flights
2. Combined Total Number of Passengers
3. Combined Total Tonnage of Air Caryos
4. Check the Following Types of Activities Existing in Your Airport:
Clij Gas Station "VJ Banks CLI Aircraft Overhaul Shop
CD Hotels CTJ Terminals and LI! Ai r Cargo Operation
tr.r; Food Preparation Parking Garages '—'Military Operation
CZ'l FAA Facilities Cj Aircraft Service 'JI! Sewage Treatment Plant
CLJ Gasoline !, Oil Center Hangars
Storage
Existing Solid Waste Collection and Disposal Practice
Please check the appropriate blank pertinent to your airport practice.
In 6 Out
r.!J Other
(specify)
Collected by
O Private
i_ Public
I._J Ai rport
LIU Combined
(spcci fy)
Hauled to:
[7Ij Directly CD Transfer
C3 Open Dump Site
t77i Land Fi 11 Si te
C-l Incinerator
C3 Shredder
CD Other Processing
Plant (specify)
Disposal
Site Owned by:
[71 Private
L__ Public
" Airport
CJ Combined
(specify)
Distance Disposal Site
fron Airport: Operated by:
iT_JO-10 niles ~ Private
C-'J 10-20 miles Cp Public
CJ 20-50 miles C.V: Airport
dl: 30-40 miles '1J Combined
L73 Greater than (specify)
40 niles
Are any of the solid waste collected at your airport recycled rather than disposed of?
C~l Yes If Yes: Tyj'Jl! Quantity (pounds/month)
a No
Present Solid Waste Collection Inventories
1. Please check the following types of storage containers used in your airport.
CU a.
CD b.
CTJ c.
m a.
C.V) c.
CJ f.
a g.
Less than 1 cy cans or barrels.
1 to -1 cy rear loading containers.
2 to 6 cy front loading containers.
10 to 20 cy "pull-on" debris boxes.
Larger than 30 cy stationary compactor containers.
Open storage requiring shovelling of waste into collection trucks.
Other (specify if checked)
2. To where do your passenger aircraft discharge their solid waste?
CZ) a. I'ach service center hangar.
CV] b. Containers locPtcd at loading piers.
l"_lc. Hefuse roon within the terminal.
Cl_ld. Other (specify it checked)
121
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Information on Solid IVastc fleiuT.ition ami Operation Costs
Please provide the following information. It is a very import nut part of this question-
naire. Please make on effort to estimate the values if you do not h;ive existing records.
1. The volume or weight of solid waste generated at your airport:
Estimated Monthly Volume (cy)
Airport Activity or Weight (tons or pounds)
The Entire Airport
If you have a breakdown of figures, please furnish the following data:
Passenger Service
Terminal
Aircraft Service
Center
Air Cargo Service
Overhaul Shop
Passenger Aircraft
2. The cost of solid vaste collection and disposal at your airport:
Combined Total
Airport Tenants All Operations
Monthly Annual Monthly Annual Monthly Annual
Collection cost
Disposal cost
Total Solid Waste
Operation Cost
Evaluation of Present Practice and Future Plans
1. Do the solid waste collection activities interfere with flight operations at your
airport?
dl Frequently O Occasionally CD Seldom CD Never
2. Considering the overall service given per dollar of cost to the airport, do you con-
sider the collection of solid waste at your airport to he:
O Excellent CD Above Average mi Average O Below Average d Poor
3. If collection is done by private collectors, please indicate types of contractual
arrangements:
(| a. Each airport tenant contract directly with the private hauler and the airport
management organization has no control of the contract or rates charged.
Ob. Each airport tenant contract directly with the private hauler but the airport
management organization retains the control of the contract or rates charged.
DC. The airport management organization, representing all tenants, contracts with
private collectors. Each tenant preserves the right to be excluded from the
contract.
did. The airport management organization, representing all tenants, contracts with
the private hauler. No tenant is permitted to make a separate contract with
the private hauler.
4. Has the airport undertaken any solid waste studies or engaged in short or long term
planning for solid waste management?
CJ Yes 1_] No
Explain briefly if you could:
Person to be contacted for additional information:
Name Title
Address
Please Return to: Mr. Kobcrt l.cc, Chief tnp.inccr
San !:rancisco International Airport
San !:rancisco, California 'J4128
122
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Appendix C
REGULATIONS
REGULATION 2, BAY AREA AIR POLLUTION CONTROL DISTRICT
(Fifth Rev., November 5, 1971)
DIVISION 4 - INCINERATION AND SALVAGE OPERATIONS
CHAPTER 1 - LIMITATIONS
§4110 SULFUR DIOXIDE. No person shall cause, let, permit,
suffer, or allow the emission from any incineration operation
or salvage operation of sulfur dioxide in excess of the
limits provided in §§3121 and 3122, Chapter 1, Division 3.
§4110.1 No person shall cause, let, permit, suffer, or
allow the emission from any incineration operation or salvage
operation of hydrogen sulfide in excess of the limitations
provided in §§11100 through 11102.8, Chapter 1, Division 11.
(Added by Resolution 635> effective November 5 3 1971.)
§4111 VISIBLE EMISSIONS
§4111.1 No person shall cause, let, permit, suffer or allow
any emission from any incineration operation or salvage
operation which does not comply with the visible emission
limitations in §3110, Chapter 1, Division 3.
§4111.2 No person shall cause, let, permit, suffer or allow
the emission from any incineration operation or salvage
operation of particles in sufficient number to cause
123
-------
annoyance to any other person, which particles are suffi-
ciently large as to be visible as individual particles at
the emission point or of such size and nature as to be
visible individually as incandescent particles. This section
4111.2 shall only apply if such particles fall on real prop-
erty other than that of the person responsible for the
emission.
§4112 PARTICULATE MATTER. (Amended by Resolution No. 258,
dated October 18, 2961.)
§4112.1 No person shall cause, let, permit, suffer, or
allow, any emission from any incineration operation or
salvage operation, capable of burning not more than 100
tons of waste or salvage material per day, of particulate
matter in excess of a concentration of 0.15 grain per
standard dry cubic foot of exhaust gas. For the purposes
of this §4112.1, the actual measured concentration of
particulate matter in the exhaust gas shall be corrected
to the concentration which the same quantity of particulate
matter would constitute in the exhaust gas, minus water
vapor, corrected to standard conditions, containing 6%
oxygen by volume, and as if no auxiliary fuel had been
used. (Amended by Resolution 258, dated October 18, 1961
and amended by Resolution 625, dated November 5, 1970.)
-------
§4112.2 No person shall cause, let, permit, suffer, or
allow, any emission from any incineration operation or
salvage operation, capable of burning more than 100 tons
of waste or salvage material per day, of particulate matter
in excess of a concentration of 0.05 grain per standard dry
cubic foot of exhaust gas. For the purposes of this 4112.2,
the actual measured concentration of particulate matter in
the exhaust gas shall be corrected to the concentration which
the same quantity of particulate matter would constitute in
the exhaust gas, minus water vapor, corrected to standard
conditions, containing 61 oxygen by volume, and as if no
auxiliary fuel had been used. (Amended by Resolution 258,
dated October 18, 1961 and amended by Resolution 635, dated
November 5, 1970.)
§4112.3 Calculation of the corrected concentration from
the actual measured concentration shall be as given in
Chapter 1, Division 8. Tests for determining compliance
with §§4112.1 and 4112.2 shall be for not less than 50
minutes in 60 consecutive minutes, or 90% of the time of
actual source operation, whichever is less. (Added by
Resolution 635, dated November 5, 1970.)
§4113 HYDROCARBONS AND CARBONYLS. No person shall cause,
let, permit, suffer, or allow the emission from any
125
-------
incineration operation or salvage operation of an exhaust
gas containing a concentration of more than 25 ppm (vol) of
total hydrocarbons, or a concentration of more than 25 ppm
(vol) of total carbonyls. For purposes of this §4113, the
actual measured concentrations of hydrocarbons and carbonyls
in the exhaust gas shall be corrected to concentrations which
the same quantities of hydrocarbons and carbonyls would
constitute in the exhaust gas minus water vapor, corrected
to standard conditions, containing 6% oxygen by volume, and
as if no auxiliary fuel had been used. (Amended by Resolu-
tion 625j dated November Ss 1970.)
126
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CALIFORNIA AGRICULTURAL CODE
VESSEL AND AIRCRAFT GARBAGE
Division 8
Chapter 1. Definitions
16001. Unless the context otherwise requires, the def-
initions in this chapter govern the construction
of this division.
16002. "Aircraft" means every description of craft or
other contrivance which is used, or capable of
being used, as a means of transportation through
the air from origins in other states or territories
or in foreign countries.
16003. "Food stores" mean fruits, vegetables, or animal
products which are carried as stores of vessels
and aircraft and includes fruits, vegetables, or
animal products which are carried in passengers'
and crews' quarters.
16004. "Garbage" means waste material such as food scraps,
table refuse, galley refuse, and refuse from
stores of vessels and aircraft, including such
127
-------
waste material in passengers' and crews' quarters,
which is derived, in whole or in part, from
fruits, vegetables, or animal products.
16005. "Territorial waters of California" means all
navigable waters of this state including all
portions of the sea within its jurisdiction
which are used by vessels or aircraft.
16006. "Vessel" means every description of craft or other
contrivance which is used, or capable of being
used, as a means of transportation in or on
coastal, intercoastal, or foreign waters.
Chapter 2. General Provisions
16051. Regulations which are adopted by the director
pursuant to this division shall not conflict
with Agricultural Research Service of the United
States Department of Agriculture orders or
regulations which pertain to garbage that is
derived from meats or meat products which orig-
inate in any country which is listed as a country
in which there are animals which are infected
with the disease known as rinderpest or with
128
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foot-and-mouth disease.
Chapter 3. Containers and Receptacles
16101. If means of incineration of, or other approved
processing for, garbage are not available aboard any
vessel or aircraft in the state, the master or other
person that is in charge of such vessel or aircraft
shall provide containers or receptacles with tight-
fitting covers in which the garbage shall be retained
while within the territorial waters of, or on the
land in, California pending incineration or approved
treatment under the supervision and pursuant to the
regulations of the director.
Chapter 4. Violations
16151. It is unlawful for any person to throw, discharge,
deposit, remove, or carry garbage, or cause, suffer,
or procure garbage to be thrown, discharged, de-
posited, removed, or carried, from any vessel, air-
craft, or any other vehicle into any territorial
waters, or onto land within the state, except for
any of the following:
129
-------
(a) Immediate burning in incinerators.
(b) Approved treatment or approved disposal under
the supervision and pursuant to the regulations
of the director.
(c) Delivery to a garbage collector that, for the
purpose of accepting garbage, is licensed by
the director or by the federal government.
16152. It is unlawful for any person to retain or maintain
garbage on any vessel, aircraft, or other vehicle with-
in the state, except in tightly closed containers or
receptacles and under such treatment as may be pre-
scribed by the director.
16153. It is unlawful for any person to remove food stores
from any vessel, aircraft, or other vehicle except
under a permit issued by the director.
16154. It is unlawful for any person to violate, or to aid,
abet, authorize, or instigate a violation of, this
division.
130
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CALIFORNIA ADMINISTRATIVE CODE
TITLE 3
Article 4. Vessel and Aircraft Garbage Disposal
770. Definitions. (a) As used in this article, all
terms defined in Section 286 of the Agricultural Code shall
have the same meaning as therein defined, unless a different
meaning is specified in this Article or is apparent from the
context,
(b) "Food stores" as defined in Section 286 of the
Agricultural Code shall be construed to be applicable to any
of the following when carried as stores of vessels or air-
craft, including those carried in passengers' and crews'
quarters: fresh fruits or fresh vegetables or animal products,
except milk or the products of milk or canned, sterilized
meats.
Note: Authority cited for Sections 770 to 778, in-
clusive: Section 286.1 Agricultural Code.
History: 1. New Sections 770 to 778 filed 5-13-46
(Register 3) .
771. Retention and Maintenance on Vessels, Aircraft
or Other Vehicles. Garbage may be retained on vessels, air-
craft or other vehicles in tightly closed containers or
131
-------
receptacles only subject to approval by the Director of
Agriculture, his deputy or inspector who may at any time
require such other disposal or treatment of garbage, con-
tainers, or receptacles, as he or they may deem necessary
for the protection of agriculture.
772. Collection or Transportation of Discharged
Garbage. No garbage shall be collected at or trans-
ported from any vessel or aircraft except for immediate
disposal by an approved method without removal from the
dock, pier, mole, or airport, unless the person, firm or
corporation collecting or transporting such garbage holds
a valid license issued by the director or by the Federal
Government, permitting such collection or transportation
to an approved incinerator or grinder, or for movement
to sea for dumping as herein provided and all garbage so
collected, transported, or otherwise moved from the dock,
pier, mole or airport shall be in tight containers.
773. Segregation of Garbage Prohibited. No segrega-
tion of garbage shall be permitted at any intermediate
point prior to delivery to an approved incinerator or
grinder, or for movement to sea for dumping, and all garbage
must be destroyed by one of the following approved methods
immediately upon arrival at such incinerator, grinder or
132
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dumping area at sea.
774. Approved Methods of Garbage Disposal. All
facilities used for garbage disposal shall have been
approved by the Director of Agriculture and/or the Fed-
eral Government and disposal shall be by one of the
following approved methods:
(a) Complete reduction to ash by an approved method
of incineration.
(b) Reduction to a liquid state by grinding and
discharge into sea water.
(c) Dumping at sea at a distance from shore which
will preclude the return ashore of any portion of such
garbage. Such dumping shall be in compliance with
the provisions of the Health and Safety Code of California.
(d) Sterilization by heat in a closed tank, chamber
or cabinet for a period of two hours at a constant mass
temperature not less than 212 F.
(1) The sterilization tank, chamber or cabinet
shall be provided with an adequate source of steam
133
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and equipped with a recording thermometer and a
mechanical agitator to assure complete and uniform
heat penetration to all parts of the mass for the
duration of the exposure.
(2) Temperature records shall be retained on
file for periodic checks by authorized inspectors.
(3) After sterilization, as provided in (d)
above, the garbage shall be disposed of in a sanitary
land fill approved by the Department.
(e) Garbage from vessels having food stores procured
only in California may be disposed of in a sanitary land
fill approved by the Department provided the vessels
have not had contact with ports outside of California.
(f) Garbage from aircraft, derived from meals served
or prepared for serving to passengers or crew while in
flight, may be disposed of by grinding through an approved
garbage disposal unit and discharge into a sewage disposal
system acceptable to the Department.
History: 1. Amendment filed 10-8-56; effective
thirtieth day thereafter (Register 56,
-------
No. 19).
2. Amendment adding new paragraph (e) filed
6-27-60; effective thirtieth day there-
after.
3. Amendment adding new paragraph (f) filed
6-11-65; effective thirtieth day there-
after.
775. Vessel and Aircraft Garbage Collector's License.
Each person, firm or corporation desiring to transport or
otherwise move garbage from the dock, pier, mole, or airport
shall make application for and obtain a license therefor
from the Director of Agriculture before engaging in such
operations. All applications for such license shall be
in writing on forms furnished by the Director upon
request. Licenses issued pursuant to this regulation
are valid until revoked by the Director.
Holders of a license from the Federal Government for
the purposes stated in this section shall not be required
to have a license therefor from the Director.
776. Permits for Removal of Food Stores. Permits to
remove food stores, as required in Section 286.4 of the
Agricultural Code, may be obtained from representatives
of the Director located at offices of the State Department
135
-------
of Agriculture in Sacramento, Los Angeles, San Francisco,
San Diego, or San Pedro, or from the county agricultural
commissioners of those counties served by maritime ports
or airports located in areas other than those served by
the State Department of Agriculture offices hereinabove
stated.
Permits shall not be issued to authorize the removal
of food stores which are restricted or prohibited entry
by any order or regulation of the California or Federal
Department of Agriculture.
777. Enforcing Officers. All authorized agents of
the Director and all state plant quarantine officers are
empowered to carry out all the provisions of these regula-
tions .
778. Subject to Other Rules and Regulations. Com-
pliance with the provisions of this article, governing
the disposal of vessel and aircraft garbage, shall not
be construed to be compliance with the provisions of any
rules or regulations promulgated by any other official
agency or officer or promulgated under authority of the
provisions of the Agricultural Code other than Chapter 4
of Division 2 of said Code.
136
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NOTE:
In Section 770 (a) above, Agricultural Code Section 286
referred to is now Sections 16001-16006.
In Section 770 (b) above, Agricultural Code Section 286
referred to is now Section 16003.
In Section 776 above, Agricultural Code Section 286.4
referred to is now Section 16153.
In Section 778 above, Agricultural Code Chapter 4 of
Division 2 is now Division 8.
Uff758
137 * U.S GOVEBNMEUT PRITOG OfFICL 1973— 759-551/1056
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