United States
Environmental Protection
Agency
Region 4
345 Courtland Street, NE
Atlanta, GA 30365
EPA 904/10-84 125
November 1984
xvEPA
Environmental
Assessment
Mountain Communities
Wastewater Management
Alternatives Report
Volume II - Technical Engineering
Alternatives
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IV - ATLANTA
MOUNTAIN COMMUNITIES WASTEWATER
MANAGEMENT ASSESSMENT
ALTERNATIVES REPORT
VOLUME II
NOVEMBER 1984
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VOLUME II
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES ii
INTRODUCTION iv
Chapter 3 TECHNICAL ENGINEERING ALTERNATIVES 3-1
3.1 Introduction 3-1
3.2 Wastewater Engineering Technique 3-3
3.2.1 Wastewater Treatment Containment and 3-3
Disposal for Individual Establishments
3.2.2 Cluster Systems 3-9
3.3 Installation/Construction Techniques 3-20
3.4 Operation, Maintenance and Repair 3-25
3.5 Enhancement Techniques for Small Wastewater 3-36
Systems
3.6 Preferred Design Practices 3-39
3.7 Evaluation of Alternative Engineering Techniques 3-43
FACT SHEETS
BIBLIOGRAPHY
APPENDICES
II-A Site Soil Survey Procedures
II-B State Health Department Contacts
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VOLUME II
LIST OF TABLES
No. Title
Page
3-1 Wastewater Engineering Techniques for Individual Systems in 3-5
Mountainous Areas
3-2 Limiting Characteristics of Wastewater Disposal Techniques 3-6
for Individual Establishments and Cluster Systems
3-3 Relationship Between Wastewater Application Rates and 3-10
Residential On-Site Wastewater Disposal Space Requirements
3-4 Wastewater Engineering Techniques for Cluster Systems in 3-11
Mountainous Areas
3-5 Design Features of Land Application Techniques for Cluster 3-14
and Small Community Systems
3-6 Wastewater Engineering Techniques for Small Community Systems 3-16
in Mountainous Areas
3-7 Wastewater Engineering Techniques for Centralized Systems in 3-17
Mountainous Areas
3-8 Limiting Characteristics of Wastewater Collection Technique 3-18
3-9 Methods for Avoiding Common Problems for Installing Small 3-21
Wastewater Systems
3-10 Operation, Maintenance and Repair of Small Wastewater Systems 3-26
3-11 Estimated Septic Tank Pumping Frequencies (In Years) for 3-34
Year-Round Residences
3-12 Operation, Maintenance and Repair (OMR) Activities for Cluster, 3-37
Small Community and Centralized Wastewater Techniques
3-13 Constraints Which May Affect the Selection of Appropriate 3-46
Engineering Techniques
3-14 Various Site Constraints Which Will Affect Selection of 3-47
Disposal Techniques
3-15 Costing Considerations 3-48
3-16 Environmental Factors That are Important in the Selection 3-49
Process
3-17 Operation Considerations for Alternative Wastewater Engineering 3-50
Systems for Rural Areas
3-18 Implementation Considerations for All Types of Wastewater 3-51
Systems
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VOLUME II
LIST OF FIGURES
Following
No. Title Page
3-1 Fact Sheet Septic Tank 3-54
3-2 Fact Sheet Aerobic Treatment 3-54
3-3 Fact Sheet Sand Filtration 3-54
3-4 Fact Sheet Disinfection 3-54
3-5 Fact Sheet Holding Tank 3-54
3-6 Fact Sheet Privy 3-54
3-7 Fact Sheet Siphon 3-54
3-8 Fact Sheet Pumping Tank 3-54
3-9 Fact Sheet Soil Absorption Trenches 3-54
3-10 Fact Sheet Soil Absorption Seepage Bed 3-54
3-11 Fact Sheet Soil Absorption Mound 3-54
3-12 Fact Sheet Soil Absorption Trenches Operated in Parallel 3-54
3-13 Fact Sheet Soil Absorption, Distribution of Effluent 3-54
With Drop Boxes
3-14 Fact Sheet Soil Absorption, Subsurface Sand Filter 3-54
Without Under Drains
3-15 Fact Sheet Soil Absorption, Filled/Built-Up Area 3-54
3-16 Fact Sheet Soil Absorption, Low-Pressure Pipe 3-54
3-17 Fact Sheet Soil Absorption, Shallow Trench(es) 3-54
3-18 Fact Sheet Soil Absorption, Alternating Trench System 3-54
With Diversion Valve
3-19 Fact Sheet Septic Tank-Sand Filtration-Irrigation 3-54
3-20 Fact Sheet Evapotranspiration Bed 3-54
3-21 Minimum Isolation Distances 3-6
3-22 Fact Sheet Small-Diameter Gravity Sewers 3-54
3-23 Fact Sheet Septic Tank Effluent Pump, Pressure System 3-54
3-24 Fact Sheet Grinder Pumps 3-54
3-25 Fact Sheet Lagoon 3-54
3-26 Fact Sheet Marsh-Pond-Meadow 3-54
3-27 Fact Sheet Irrigation 3-54
11
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VOLUME II
LIST OF FIGURES (cont'd)
Following
No. Title Page
3-28 Fact Sheet Conventional Gravity Sewers 3-54
3-29 Fact Sheet Vacuum Sewers 3-54
3-30 Fact Sheet Preliminary Treatment 3-54
3-31 Fact Sheet Rotating Biological Contactor (RBC) 3-54
3-32 Fact Sheet Trickling Filter 3-54
3-33 Fact Sheet Contact Stabilization 3-54
3-34 Fact Sheet Extended Aeration/Activated Sludge 3-54
3-35 Fact Sheet Advanced Treatment 3-54
3-36 Fact Sheet Sludge Treatment 3-54
3-37 Fact Sheet Septage or Sludge Disposal 3-54
3-38 Installation of Lateral Cleanout 3-34
3-39 Fact Sheet Waste Flow Reduction, Water Conservation 3-54
3-40 Fact Sheet Waste Flow Reduction, Wastewater Recycle/Reuse 3-54
3-41 Curtain Drain 3-39
3-42 Recommended Methodology for Selecting Preferred Engineering 3-43
Techniques for New Systems
3-43 Recommended Methodology for Selecting Preferred System 3-52
Rehabilitation Techniques
(Fact Sheets are located at back of Chapter 3)
111
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VOLUME II
INTRODUCTION
This is the second of four volumes which make up the Final Alternatives
Development Report for the Mountain Communities Wastewater Management
Assessment. This volume contains Chapter 3Technical Engineering Altern-
atives.
Chapter Three describes applicable technical approaches to wastewater
management in small mountainous communities by system type (on-site,
cluster, small community and centralized). Tabular summariesfact sheets-
-of each system are also included. Finally, a method is presented for
selecting the most appropriate technique under given circumstances.
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CHAPTER 3
TECHNICAL ENGINEERING ALTERNATIVES
3.1 Introduction
The 82-county study area, called the highlands portion of southeastern
Appalachia, has both environmental limitations and a past record of less-
than-average funding available for wastewater management systems. The
environmental limitations include steep slopes, shallow soils and shallow
depths to groundwater. Less-than-average funding has resulted in a
corresponding lack of proper design, installation and maintenance of many
wastewater systems throughout the study area. Some of the problems include
excessive amounts of water entering the wastewater system, improper
locations in relation to soil characteristics, locations of water supply
springs and wells, wastewater systems not large enough to handle maximum
flows, systems that do not provide proper wastewater treatment or disposal,
and lack of periodic maintenance and repair.
This chapter presents a wide assortment of alternative wastewater
techniques which can be used for properly managing wastewater in rural
mountain communities, households and businesses. The techniques presented
include both designs for various types of wastewater systems and methods
for repairing or maintaining existing systems. Both the techniques and the
methodologies can be relevant for low-income rural residents, families with
second homes, and residents in dense clusters of homes such as small
communities, recreational areas or mobile home parks. Certain techniques
and methodologies may be more relevant to one type of resident or homeowner
than another.
Chapter three is organized into seven sections based on the different
activities involved in wastewater engineeringplanning, design, instal-
lation and operation/maintenance/repair. Section 3.2 provides a summary
description of alternative designs for wastewater facilities suitable for
3-1
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individual homesites, cluster and small community systems, and larger scale
collection and treatment systems. The techniques suitable for each of these
settings are summarized on tables. Each technique is then described in
greater detail on a fold-out fact sheet which summarizes specific uses,
provides examples of uses within Region IV, contact persons and manu-
facturers. Finally, tables are presented which summarize the natural
features which may limit the application of several general techniques.
Sections 3.3 and 3.4 discuss installation and construction, and
operation, maintenance and repair issues associated with each alternative.
Sections 3.5 and 3.6 discuss additional factors which will affect system
performance including methods of enhancing performance of existing systems
and practices which, if followed, could ensure better system design.
The final section of the Chapter, 3.7, sets forth a recommended
procedure which local communities can use to identify the technical
alternative or alternatives which are most appropriate for their needs and
community conditions.
Cost information for each of the technical alternatives presented in this
chapter is not given in any detail. Specific costs will be developed in
detail in the final report.
3-2
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3.2 Wastewater Engineering Techniques
Numerous wastewater engineering techniques exist that are technically
sound, efficient and easily adaptable to the complex topography and
scattered population centers in southeastern Appalachia. Physical con-
straints pose problems for planning, design and installation of both large
and small systems. Shallow depths to rock and groundwater hamper
installation of system components (e.g. septic tanks and sewer conveyance
systems). Installation of facilities can become costly because of rock
excavation, and groundwater infiltration can lead to hydraulic overloading
of both large and small facilities. All wastewater engineering facilities
must be well planned and adapted to local environmental site conditions in
order to be effective. Improper siting can lead to poor performance and
high costs. Therefore, before considering the implementation of any sewage
facility components, an evaluation should be conducted to assess landscape
position, topography, drainage, geology and soil characteristics. Siting
septic tank-soil absorption systems must also consider separation distances
from wells and springs and other features which affect system performance.
3.2.1 Wastewater Treatment, Containment and Disposal For Individual
Establishments
Wastewater engineering techniques utilized at individual homes and
business establishments usually include a septic tank in conjunction with
one of an array of soil absorption options for providing final treatment
and disposal. Table 3-1 lists the many techniques available. Basically,
soil absorption techniques consist of beds, trenches and mounds all of which
can be constructed in various configurations to adjust to specific physical
and site conditions. Where soils are deep and well-drained, trenches are
preferred over beds due to the increased side wall area in trench
configurations. Mounds extend the use of soil absorption particularly
within areas where shallow soils of only two to three feet in depth are
available. Mound systems allow the wastewater to be distributed over a more
permeable topsoil layer thereby allowing the wastewater to be accepted and
3-3
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treated before reaching restrictive features such as fractured rock
groundwater or a slowly permeable subsoil layer. Figures 3-1 through 3-20
present detailed descriptions of these different techniques which may be
appropriate for individual establishments. More than one technique can be
suitable for a particular site. Most types of equipment are commonly
available. Names of specific manufacturers have been extracted from Public
Works Journal Corporation, 1984; any listing of manufacturers does not
indicate U. S. EPA endorsement. A list of both state health department and
state environmental agency personnel, which are referred to in this
chapter, appear in Appendix I-B.
Beds, trenches and mounds all have siting limitations related to land
slope, hydraulic conductivity of the underlying soil, and depth of
unsaturated soil below the disposal pipe. These are summarized on Table 3-
2. Many limitations can be overcome with mounds, shallow placement or other
variations of conventional on-site systems. Minimum distances separating
wastewater units from other types of facilities are shown in Figure 3-21.
Minimum design recommendations for on-site techniques have been published
(U.S. EPA, 1980a; Salvato, 1982 and state guidelines).
Sizes of disposal areas shown in Table 3-2 are based on wastewater
disposal rates of approximately three inches per week for beds, trenches and
mounds and 12 to 14 inches per week for other types of on-site disposal. Such
rates are much slower than soil hydraulic conductivity primarily in order to
retain the capacity of soil to treat wastewater as it percolates downward to
the water table and bedrock. Clearly, seepage pits and leaching chambers
are not as preferred as beds, trenches or mounds in locations with limited
unsaturated soil depth. Elevated mounds can be utilized with as little as
two feet of unsaturated soil depth below the filter material. In areas with
less than two feet of suitable, unsaturated soil, use of an on-site disposal
system should be avoided in nearly all circumstances.
Various types of modifications to individual disposal systems are
available. For example, a pump or siphon can be utilized to distribute
wastewater evenly throughout a trench, bed or mound. These modifications
3-4
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TABLE 3-1
WASTEWATER ENGINEERING TECHNIQUES
FOR INDIVIDUAL SYSTEMS IN MOUNTAINOUS AREAS
TREATMENT
Septic Tank
or
Aerobic Unit
CONTAINMENT AND TRANSPORT
Privy
Holding Tank
DISPOSAL
Soil Absorption^
Trenches (or pits)
. Bed
Mound
Evapotranspiration
Septic Tank
and
Sand Filter
Siphon
Pumping Tank
Soil Absorption
(see above)
Irrigation^
open land
forest land
Surface waters^
Evapotranspiration
Lagoon/Pond
Other soil absorption techniques are available that are variations of
the basic absorption techniques (see Figures 3-11 through 3-17).
Disinfection is required prior to disposal.
3-5
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TABLE 3-2
LIMITING CHARACTERISTICS OF WASTEWATER DISPOSAL TECHNIQUES
FOR INDIVIDUAL ESTABLISHMENTS AND CLUSTER SYSTEMS
Soil absorption
beds (fields)
and trenches
Typical Size of
Disposal Area *
(sq.feet of soil
contact area per
bedroom}
400
Maximum Land Slope^
(percent)
25 for trenches
5 for beds
Minimum/Maximum
Soil Hydraulic Conductivity3
(inches per hour)
0.2/6.0
Minimum Recommended Depths of Un-
saturated Soil Below Pipes (feet)
To Water Table To Bedrock
2-4
1 Based on soil hydraulic conductivity, resting of soil to enhance treatment, and 100 gallons
of wastewater generated per day per bedroom.
2 Steep slopes pose problems with operating installation equipment. Special equipment or the
use of hand tools may allow installation on steeper slopes.
3 Based on results from percolation tests conducted at the disposal site.
^ Not shown on Pact Sheets; these techniques are variations of more conventional soil
absorption techniques.
2-4
Seepage pits
OJ
1 A
°* Leaching chambers*
Mounds
Eavpotranspiration
beds
85 5
85 5
400 15
70 5
1.0/6.0 15
1.0/6.0 15
0.2/0.5 2
0.02/0.2 1
15
15
2
1
Sources: U.S. EPA, 1980 and Pennsylvania DER, 1983.
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50'- 100 MINIMUM
SURFACE DROINUGEWAY
PREFERRED MINIMUM HORIZONTAL DISTANCES
FROM SEPTIC TANK OR ABSORPTION AREA TO:
WATER SUPPLY WELLS 50-100 FEET
BUILDING FOUNDATIONS 10- 20 FEET
PRESSURE WATER LINES 10- 20 FEET
DRIVE WAYS 5-10 FEET
POOLS 10 - 20 FEET
ADJACENT ON-LOT SYSTEMS 10- 20 FEET
STREAMS AND LAKES 50-100 FEET
Wen
SOURCE: PA. DER,!983
MINIMUM
ISOLATION DISTANCES
FIGURE 3-21
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each present various possibilities for enhancing system performance as
discussed in Section 3.6.
Typical requirements for sizes of on-site disposal areas are presented
in Table 3-3. Land area required for wastewater disposal usually depends
upon soil, hydraulic conductivity, the ability of the soil to treat
wastewater and depths to both the water table and bedrock. Design flows for
on-site facilities are commonly 300 to 400 gallons per day per household to
account for 60 to 75 gallons per person per day of average wastewater
generation and also to account for peak flows to a system with a septic tank
or some other type of treatment unit. Wastewater detention times within
septic tanks are usually 24 to 36 hours at a minimum, while aerobic units for
on-site or small community systems commonly have 8 to 10 hour detention
times.
Surface area requirements for trenches can be significantly reduced
from the values shown in Table 3-3 by utilizing wider trenches. However,
wide trenches are difficult to construct on steeply-sloping lots while
maintaining the recommended 2 to 4 feet of vertical separation from ground-
water, fractured rock or other restrictive features.
It is important here to discuss the impact non-residential wastes can
have on the standard septic tank. Wastewater effluents from commercial/
industrial activities vary significantly from residential wastes. The
biodegradeability of these wastes can differ due to different fractions of
settleable, floatable and dissolved solids, thereby changing the efficiency
of the standard septic tank. Standard septic tank designs are often
inappropriate for treating non-residential wastewaters. In the case of
restaurant wastes, designers must consider the high grease loadings to the
treatment unit. Laundromats may require special prefilters in the
treatment process to ward off potential soil clogging due to high 6005
levels, phosphate precipitates and lint. Lastly, schools without showers
may be producing high concentrations of pollutants necessitating additional
treatment from non-standard design septic tanks or aerobic units.
3-7
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Given the physical problems in portions of the study area, many of the
selected wastewater management techniques will consist of using some type
of primary treatment followed by a soil absorption system for final
treatment and disposal. For many parts of the study area, use of the septic
tank-soil absorption system will be the preferred disposal/treatment
alternative, simply due to its proven performance and lowest cost of
installation and operation. Many people have not considered the septic
tank-soil absorption system to be an effective, long-term solution to their
wastewater problems. In fact, however, a properly sited, designed,
installed and maintained septic tank-soil absorption system will effec-
tively renovate wastewater and continue to function properly for twenty
(20) years or more. Research conducted by E.J. Tyler, et al, 1977, concluded
that the soil, in addition to the septic tank itself, is indeed capable of
removing a very high percentage of the organisms and substances which are
potentially harmful to human health and the environment, making this type
system an environmentally sound alternative when properly sited, designed,
installed and maintained.
3-8
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3.2.2 Cluster Systems
The term "cluster systems" is used to denote a single wastewater system
that collects, treats and disposes wastewater from a group of congregated
establishments. Cluster systems can be more feasible from a public health
and environmental standpoint than individual systems if, 1) establishments
are too densely congregated for individual systems (less than one-third to
one-half of an acre per establishment), 2) if variable soil conditions allow
a large absorption area for a cluster to be more technologically feasible
than absorption areas at each establishment, or, 3) if use of any absorption
area is not possible and wastewater needs to be discharged to a surface
water body. When considering soil absorption, this cluster approach often
requires a considerable amount of land area for construction of both an
absorption area and a reserve area for a potential replacement system.
Table 3-4 describes various approaches which may be appropriate for cluster
systems. Fact sheets included as Figures 3-22 through 3-27 provide more
detailed information on techniques for cluster systems. In addition to
techniques included on these fact sheets, many of the alternatives
addressed under the section on individual systems may also be appropriate.
Linking individual establishments into one wastewater system requires
a collection system that is designed to handle small flows and is suitable
in the rough, hilly terrain found in mountainous areas. Depending on
landscape features, gravity flow can be utilized to allow septic tanks to
be connected by gravity to a package treatment facility. Pressure sewers
can also be utilized for wastewater conveyance. Pressure sewers transmit
pumped wastewater thereby allowing greater flexibility in mountainous
terrain, because they can be utilized regardless of land topography. In
addition, pressure sewers, by their design, prevent infiltration of
rainwater and groundwater allowing for the use of smaller and cheaper small
diameter pipe. Although construction of these sewers is less expensive than
conventional gravity sewers, use and maintenance of pumps and controls may
potentially offset any savings.
3-9
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TABLE 3-3
RELATIONSHIP BETWEEN WASTEWATER APPLICATION RATES AND RESIDENTIAL
ON-SITE WASTEWATER DISPOSAL SPACE REQUIREMENTS
u>
H1
0
Wastewater
Application Rate
gallons per day
per square foot
0.05
0.20
0.50
Minimum
Absorption Area
Requirement
square foot
6,000
1,500
600
Mounds
Minimum surface
Area, sq . ft.
6,000
1,500
600
Typical Dimensions
ft. by ft.
(120'x50')
<200'x30')
(15'xlOO1)
(10'x60')
Seepage Beds
Minimum Total
Surface Area
6,000
1,500
600
or Fields
Typical
Dimensions
ft. by ft.
100 'x60'
or
23100 'x30'
15'xlOO1
30 ^SO-
lO 'x60'
20'x30'
Trenches
Minimum Total Typical
Surface Area ft. by
sq. ft.
25,000 114'x
5,800 58'x
1,800 18*x
Dimensions
ft.
100'
100 '
100*
1.20
250
250
(10'x25')
250
10'x25'
750
15'x 50'
Assumptions
Design flow of 300 gallons per day per household.
Trenches2 feet wideMaximum length 100 feet and spacing between laterals of 6 feet.
Dual Beds or Fields20 foot separation distance. Surface and subsurface soil horizons have the
same hydraulic conductivity.
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TABLE 3-4
WASTEWATER ENGINEERING TECHNIQUES
FOR CLUSTER SYSTEMS IN MOUNTAINOUS AREAS
COLLECTION
Small Diameter
Sewers
Gravity
Pressure
(with either effluent
pumps or grinder
pumps)
Holding Tanks
TREATMENT
Septic Tank
Aerobic Unit
Septic Tank and
Sand Filter2
Lagoon
Mar sh-pond-meadow
(artificial or natural)
DISPOSAL
Soil Absorption at one
site1
Trenches (or pits)
Bed(s)
Mound(s)
Evapotranspiration
Irrigation-*
open lands
forest land
Surface Waters3
1 Other soil absorption techniques are available that are variations of the
basic absorption techniques (see Figures 3-11 through 3-17).
*)
* The filter can provide for effluent to be recirculated.
3 Disinfection is required prior to disposal.
11
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A third conceivable option for wastewater collection is the use of
vacuum sewers. A vacuum pump at a pumping station provides the vacuum
source with valves located at each establishment. At selected intervals,
sewer pipes must rise sharply to form a pocket where wastewater can collect.
Air forces wastewater to the next section of downward sloping pipe. The
advantages of reduced infiltration, reduced inflow and lower installation
costs when compared to gravity sewers are the same advantages as are
available for pressure sewers. Energy is required and equipment main-
tenance may be hindered by limited availability of parts. Vacuum sewers
also have not been tested and utilized in more than a few innovative sewer
systems.
Wastewater treatment techniques for cluster systems, in addition to the
possible use of septic tanks at individual establishments, include use of
one treatment facility designed and constructed as one system rather than
as individual treatment units. If wastewater is to be discharged to a
surface water body or above-ground to a land disposal site, secondary
wastewater treatment, e.g. a lagoon or a biological treatment facility, is
required by Federal regulations. Extended aeration is the most commonly
utilized biological treatment unit for cluster treatment facilities.
Wastewater disposal options include use of soil absorption trenches,
beds or mounds or discharge above-ground to an available land area or to a
local water body. Table 3-5 presents design features which may limit the
use of different land disposal techniques. Limiting factors for other
disposal techniques were presented on Table 3-2. Any sludge from the
treatment facility must also be managed. Costs and state permitting
requirements (based on public health and environmental constraints) are the
primary factors in selecting the most suitable disposal option.
3.2.3 Small Community Systems
The term "small community systems" is utilized in this assessment to
denote wastewater collection, treatment and disposal facilities that handle
3-12
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flows from more than a handful of establishments but less than 100,000
gallons per day. Techniques for small communities include many of the
cluster system techniques already described. Small community techniques
are applicable when individual, cluster-type systems cannot adequately
handle the wastewater management needs of the service area. Where sewage
volumes and service areas are typically large, utilization of these
techniques will require more in-depth planning and an analysis of alter-
natives to reach a cost-effective solution. In some instances the
recommended plan may include several individual systems, several cluster or
grouped facilities and possibly a large treatment unit that will service the
needs of the more densely populated section of a small community.
Table 3-6 lists various techniques most often associated with managing
waste flows from small communities. Wastewater disposal via underground
soil absorption is usually too costly for all but the smallest community
systems. For the larger systems, various types of biological treatment
including rotating biological contactors merit evaluation. Figures 3-22
through 3-35 are fact sheets which describe wastewater engineering tech-
niques particularly appropriate for small communities. Other techniques
described on Figures 3-1 through 3-20 may also be used. Figures 3-36 and 3-
37 describe sludge treatment and disposal techniques respectively.
3.2.4 Centralized Systems
The term "centralized systems" is defined here as any collection,
treatment and disposal system that can handle more than 100,000 gallons per
day of incoming wastewater. Centralized systems have been utilized
extensively in the past. They are also complex systems that are generally
proven and understood by engineers and designers; therefore, centralized
systems are still quite popular and in widespread use, although emphasis on
planning of such facilities is declining due to the high cost of con-
struction, operation and maintenance. Like the other previously discussed
wastewater management techniques, centralized systems may utilize various
types of collection and conveyance techniques to serve lower density
centers in the mountain communities. Centralized systems are often not
suitable for construction in hilly terrain areas with sparse populations.
3- 13
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TABLE 3-5
DESIGN FEATURES OF LAND APPLICATION TECHNIQUES
FOR CLUSTER AND SMALL COMMUNITY SYSTEMS
Application Technique(s)
Common application rate,
inches per week
Land required, acres per
10,000 gal/day applied
(not including buffer
area, roads or ditches)1
Method by which wastewater
is ultimately disposed
Irrigation (including
surface or subsurface
application)
Rapid Infiltration
Surface-sprinklers, lagoons Sprinklers, pipe or
or pipe distribution ditch distribution
Subsurface-perforated pipes
to 2"/week
1 or more
Groundwater or subsurface
runoff to surface water
20 to 30
0.1 or more
Groundwater
Overland Flow
Natural or Artificial
Wetlands
Gravity flow from Gravity, pressure, or
higher elevation sprinklers
Perforated Plastic pipe
Gated irrigation
pipes
2 to 16
1 or more
Groundwater or sub-
surface runoff to
surface water
Less than 5 for natural
wetlands
Multiple
Possible multiple land uses
Land Slope
Agriculture
Silviculture
Horticulture
Recreation
Less than 20 percent
on cultivated lands
Recreation
Not critical
Agriculture
Silviculture
2 to 8 percent^
Agriculture
Recreation
Less than 5 percent
Minimum depth to
water table
OMR needs specifically
for disposal
3 to 4 feet
10 ft. unless under-
drained
Not critical
Not critical
1) Temporary storage 1) Possibly storage 1) Temporary storage 1) Possibly vegetation
during wet or cold during cold periods during cold weather removal
periods 2) Disc or Scarifier 2) Vegetation removal
2) Maintenance of sprinklers for basin
3) Vegetation removal 3) Periodic mowing of
vegetation
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CO
I
TABLE 3-5 (cont.)
DESIGN FEATURES OF LAND APPLICATION TECHNIQUES
FOR CLUSTER AND SMALL COMMUNITY SYSTEMS
^ Assumes 5 days per week of operation
* Steeper grades might be feasible with reduced hydraulic loadings
OMR - Operation, Maintenance and Repair
Sources of information: U.S. EPA, 1980 (CD-53) and U.S. EPA, 1981.
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TABLE 3- 6
V^ASTEWATER ENGINEERING TECHNIQUES
FOR SMALL COMMUNITY SYSTEMS IN MOUNTAINOUS AREAS
COLLECTION1
Gravity Sewers
conventional
small-diameter
Pressure Sewers
Septic tank effluent
pumps
Grinder pumps
Vacuum Sewers
TREATMENT
Preliminary Treatment
DISPOSAL
Soil Absorption at
community site(s)^
Trenches or pits
Beds
Mounds
Irrigation
crop land
open land
forest land
Surface waters-
Aerobic treatment
Rotating Biological
contactors
Trickling Filters
Contact stabilization
Extended aeration^
Lagoons
Filters5
Mar sh/Pond/Meadow
(artificial or natural)
1 Any sewer system can be designed as a conventional or small-diameter system.
2 Other soil absorption techniques are available that are variations of the
basic absorption techniques (see Figures 3-11 through 3-17).
3 Disinfection is required prior to disposal.
4 Extended aeration is a form of the activated sludge process (see Figure 3-32) .
5 Filters can provide for effluent to be recirculated.
3-16
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TABLE 3-7
WASTEWATER ENGINEERING TECHNIQUES
FOR CENTRALIZED SYSTEMS IN MOUNTAINOUS AREAS
COLLECTION
TREATMENT
DISPOSAL
Large diameter
Gravity sewers
(with pumping stations
as needed)
Activated sludge
Irrigation^-
crop land
open land
forest land
Surface waters
Rotating biological
contactors
Trickling filters
Lagoons
Filters2
Advanced treatment
processes for nitrogen,
phosphorous, carbon,
metal and/or organic
removal
1 Disinfection is required prior to disposal.
2 Filters can provide for effluent to be recirculated.
3-17
-------
TABLE 3-8
LIMITING CHARACTERISTICS OF WASTEWATER COLLECTION TECHNIQUES
Gravity Sewers
(conventional and
small-diameter)
Maximum Allowable
Land Slope (percent)
20
Minimum Recommended Depths of
Native Soils Below
To Water Table
To Bedrock
to
I
Pressure Sewers
(with septic tank effluent
pumps or grinder pumps)
Vacuum Sewers
20
-------
Table 3-7 summarizes the wastewater collection, treatment and disposal
techniques most commonly associated with centralized systems. Table 3-8
summarizes some of the natural features which would limit installation of
gravity and pressure collection systems. These systems typically consist
of large diameter gravity sewers and force mains, pumping stations and
elaborate treatment facilities capable of producing a high quality
effluent suitable for stream discharge or land disposal via irrigation,
rapid infiltration or overland flow. The various wastewater and sludge
treatment techniques are described only in broad categories; many man-
ufacturers have developed their own unique treatment processes. En-
gineering parameters for the design of relatively large centralized
treatment techniques have been well studied and tested. Treatment of
wastewater to quality levels much higher than secondary treatment can be
achieved via processes that convert or remove nitrogen, phosphorus, organic
carbon, metals and organic compounds. Many of those engineering techniques
which are applicable in small communities are also applicable in large-
scale centralized systems.
3-19
-------
3.3 Installation/Construction Techniques
Sewage facilities which have been properly sited and designed need to
be installed not only according to specifications but by also using
appropriate construction techniques. Any one of a number of problems
following system design could completely eliminate the system's effec-
tiveness. Such potential problems during installation include:
installation at a less-preferred location than designed (e.g. a
location with concave slopes),
excessively deep installation of any soil absorption system,
high soil moisture during installation,
backfilling causing damage to pipes, tanks, or other
buried structures,
compaction of soil in and around the downslope area, once
the pipes or tanks are in place,
not adhering to specifications such as placement of coarse
material beneath pipes or tanks, or leveling of
in-ground facilities,
site damage following preliminary evaluation and design,
(e.g. soil removal, compaction),
construction which does not follow land contours,
inadequate depths or protection to avoid freezing of
in-ground facilities,
lack of field testing following installation but prior to
the contractor leaving the site (such as pressure testing
pumps and siphons or water testing a level distribution
box) ,
insufficient diversion of runoff to avoid infiltration and
possible hydraulic overloading.
Methods and reasons for addressing each of these potential problems are
presented in Table 3-9 . While there are many potential problems, most can
3-20
-------
TABLE 3- 9
METHODS FOR AVOIDING COMMON PROBLEMS FOR
INSTALLING SMALL WASTEWATER SYSTEMS
Problem
Installation at a wrong or
different location
Methods for Avoiding Problem
Stake out preferred location (s) and lay-
out components prior to installation.
Have a qualified on-site inspector during
entire installation.
Review plans and specifications with con-
tractor at the site prior to construction.
Reasons for Avoiding Problem
Variable soil conditions (slope, hydraulic
conductivity, depths) in a small area
Location of the sewage facility in an
untested area may have total, different
hydraulic characteristics and result in
premature overloading and failure.
Excessively deep installation
Have a qualified inspector on-site during
excavation.
Shallow available soil depth to water table
or bedrock
U)
NJ
Figh soil moisture level
during installation
Backfilling causing damage
to pipes and tanks
Compaction of soil in or
around the absorption area
Require soil moisture test to be performed
prior to the start of construction by a
qualified inspector or soil scientist.
Lightweight track equipment and backhoes
should be utilized to place protective
layers of fill on sewage facilities working
principally from the upslope side.
Work only during dry soil conditions (hand
test or soil moisture meter)
Have a qualified on-site inspector to guard
against damaging installation practices
Critical downslope areas can be roped or
fenced off
High moisture conditins can result in
irreversible soil smearing and high
reductions in soil permeability
Wastewater loadings can be localized and
result in clogging if in particular
gravity fed laterals are not level follow-
ing backfilling operations
Excavation of trenches, beds and other land
disposal systems can result in compactions
of downslope area. Movement of
water may be restricted due to compaction
of down-gradient soils.
Not adhering to specifications
such as placement of coarse
material beneath pipes or
tanks
Have a qualified inspector on site during
installation
Adhering to specifications can make the
differnece between proper performance and
failure.
-------
TABLE 3-9 (cont.)
METHODS FOR AVOIDING COMMON PROBLEMS FOR
INSTALLING SMALL WASTEWATER SYSTEMS
Problem
Excessive water entering
system due to improper
seals
£ite damage following pre-
liminary evaluation
i
M
M
Construction which does not
follow contours
Inadequate depths to avoid
freezing of in-ground
facilities
Reasons for Avoiding Problem
. Extraneous water in the system places a
burden on the absorption system and may
result in seasonal hydraulic overloading
of the system and possible breakout of
sewage.
Methods for Avoiding Problem
Septic tanks and pumping chambers can be
installed during wet periods to check for
water tightness (if potential compaction
problems can be controlled).
Septic tank and pumping chambers can be
filled with water to check for leaks.
These facilities can also be checked
after rainfall events for inflow around
bad seals.
All sites should be inspected prior to the
start of construction to verify that the
tested site has remained in a natural con-
dition. This means soil has not been
disturbed or removed or the site has been
damaged by wheel compaction.
Staking, roping and/or fencing off the
area immediately following the site
evaluation
Staking and laying out the system prior . Trenches, if not properly installed with
to final design the contour will result in deep locations
at one end and/or shallow settings at the
other. Deep excavations may result in the
location of laterals in less permeable
material or insufficient vertical separation
between the bed or trench and limiting or
restrictive features (e.g. groundwater or
fractured rock).
Require sewers under future driveways to Lack of insulation of building sewer under
Many soil absorption systems are installed
or constructed quite some time after the .
site is evaluated. Soils are frequently
compacted by trucks during other construc-
tion activities. Topsoil is also sometimes
removed as part of general land shaping.
be insulated. Require design to have
pressure dosed systems drain back to dosing
chamber after cycle.
driveways which are cleared of snow may
result in freezing. Supply distribution
lines in pressurized systems too should
be drained between cycles to guard against
freezing.
-------
TABLE 3-9 (cont.)
METHODS FOR AVOIDING COMMON PROBLEMS FOR
INSTALLING SMALL WASTEWATER SYSTEMS
Problem
Lack of field testing
following installation
Excessive erosion following
construction
UJ
I
NJ
Ul
Insufficient diversion of
runoff to avoid excessive
infiltration and possible
overloading
Methods for Avoiding Problem
All sewage facilities should be water-
tested for leaks as well as operational
performance. Distribution and drop boxes
can be tested with water for proper dis-
charge.
Seed and mulch absorption area and provide
adequate stormwater diversion to control
erosive runoff.
« Require final inspection of facilities
prior to approval
In the case of sloping sites, random fill
upslope or separate diversion ditches
should be placed. Interceptor drains can
be installed to manage stormwater runoff.
Require final inspection of facilities
prior to approval
Reasons for Avoiding Problem
Small diameter holes are prone to clogging
from leftover construction materials left
in laterals, pumping tanks, etc. Clean-
outs are recommended on all laterals to
facilitate routine maintenance.
Minimum protective covers are usually
placed over soil absorption system though
properly designed thin cover materials
resulting from shoddy backfilling or
landscaping may result in surface breakout
of sewage and saturation of the absorption
area during rainfall events.
Soil absorption systems are frequently
constructed on hillsides in such a way
as to trap storm runoff and promote in-
filtration and system overload. Final
shaping with small lightweight equipment
can result in an aesthetically pleasing
configuration that promotes runoff instead
of infiltration.
-------
be minimized or avoided by application of relatively simple methods. Use of
a qualified inspector on-site and good communication between the inspector
and the contractor is a method for controlling many potential problems
immediately prior to and during installation. Some situations, such as
unnecessary soil compaction by the contractor's equipment and inadequate
leveling of in-ground facilities, can be controlled by the inspector and the
contractor working together. Roping off the proposed absorption area is a
simple, effective measure for avoiding unnecessary soil compaction.
Leveling of the distribution box is the biggest problem faced by installers
in four rural North Carolina counties (Berkowitz, 1981). The absorption
beds and trenches need to be aligned at a proper, uniform slope as well.
System testing prior to covering the installation is a relatively easy,
quick and effective method for avoiding many potential problems.
The methods presented in Table 3-9 are pertinent to various engineering
\
techniques, but the methods are particularly valuable for underground
facilities. Once underground facilities are in place and covered, the
process of correcting problems suddenly becomes much more costly and time-
consuming than if the problem is corrected before burial.
3-24
-------
3.4 Operation, Maintenance and Repair
Benefits of proper design and installation of small community systems
can be completely overshadowed by improper or infrequent operation,
maintenance and/or repair (OMR) activities. Inadequate maintenance is a
primary reason cited by North Carolina sanitarians for septic tank system
malfunctions (Berkowitz, 1981). Some problems which can develop even in a
properly designed and installed system are:
excessive amounts of water entering the wastewater system
resulting in backups to homes or flooding of the disposal site,
uneven wastewater distribution,
seepage from the disposal area and surface seepage or breakout,
resulting in pollution of ground or surface waters.
In general, the systems with the most hardware and moving parts are those
that require the most OMR. However, techniques like a septic tank also
require periodic maintenance.
Table 3-10 presents ways that any of the problems listed previously
could be solved. Some of the remedies are much less costly and time-
consuming than others. Clearly, persons experienced in trouble-shooting
wastewater problems would preferably be utilized to assess the type of
problem being encountered and to select and implement the remedy with the
highest likelihood of being successful. Some of the remedies can be
attempted at any time during a year without interrupting system per-
formance, however, other remedies may require use of temporary holding
tanks while rehabilitation is in progress. Some remedies also may be
successful at certain locations and inappropriate at others. For example,
use of hydrogen peroxide to unclog soils is recommended primarily for sandy
soils. Inappropriate chemical treatment could be detrimental if the
ability of the soil to provide wastewater treatment is lost.
One of the most frustrating problems encountered by a sanitarian is
receiving numerous calls for repairs on the same day, perhaps following a
3-25
-------
Potential Problem
Plumbing back-ups
Hydraulic overloading
OJ
i
Surface Seepage or
Wetness
TABLE 3- 10
OPERATION, MAINTENANCE AND REPAIR
OF SMALL WASTEWATER SYSTEMS
Possible Remedies
Inspect and rehabilitate sewer line extending from establishment.
Inspect septic tank; review maintenance records, check condition of treatment unit,
distribution lines and boxes.
With pressurized systems, inspect lateral cleanouts for clogging slime layer back
flush. Clean and repair inoperative pump and siphons.
Divert runoff around piping and treatment disposal area-regrade surface.
Inspect and rehabilitate septic tank (or other treatment unit) .
Seal pipe connections to treatment unit and any other leaks.
Verify that roof drains and other clean water discharges are not connected
to wastewater system.
Separate laundry water and dispose of it at a different area.
Increase size of disposal field bed(s) or trench(es).
Institute water conservation measures or reuse techniques.
Retest site, determine depths to restrictive feature; expand, repair or replace
absorption area.
Calculate upgradient drainage area and hydraulic capacity of the soil/site.
Inspect septic tank pumpout to be sure adequate capacity and outlet protection are in place.
Evaluate the following structural remedies:
i. Install septic solids retaining devices
ii. Install gas deflection baffles
iii. Install nonequal volume septic tank
iv. Compartmentalize septic tank
Rest absorption area by employing wasteflow reduction/water conservation efforts
and periodic pumping of tank
Convert gravity flow system to pressure dosing for more uniform distribution
and resting.
Retest soils on the site, increase absorption area based on present day wastewater
generation e.g. clays and clay loom 0.1 gals/fts up to 0.5 gals/fts for looms
and other fine textured soils.
Provide additional wastewater treatment (install aerobic treatment unit)
Reduce amounts of water entering the wastewater system. Check plumbing figures.
Discontinue use of garbage disposal.
Chemical treatment (e.g. hydrogen peroxide) as suitable.
Avoid disposal of certain industrial wastes that can contribute to clogging.
-------
Potential Problem
Poor Wastewater
Distribution
Pollution of Underlying
Groundwater (or down-
stream surface water)
TABLE 3-10(cont.)
OPERATION, MAINTENANCE AND REPAIR
OF SMALL WASTEWATER SYSTEMS
Possible Remedies
Check distribution or drop box for:
i. level outlets - water test
ii. clogged or broken outlets
Check laterals in supply distribution system, replace or relevel using smaller
diameter pipe with fewer small diameter discharge holes.
Install sewage effluent pump or siphon to distribute wastewater through small
diameter laterals and holes.
Clean distribution network by rodding and backflushing.
Pump out septic tank(s) (or maintain other types of treatment units).
Provide additional wastewater treatment.
Modify absorption area to provide a layer of less permeable soil filter
material.
Repair/replace water supply well casing(s)
NOTE: See also Section 3.5 which describes techniques to enhance system performance.
-------
large rainfall. A program of periodic inspection and homeowner interviews
could greatly reduce such problems, before they become hazardous or
otherwise noticeable to the homeowner.
The most common on-site maintenance procedure is pumping out septic
tanks. As sludge accumulates in a septic tank, the capacity of the tank to
hold and treat incoming wastewater decreases and the quantity of solids
leaving the septic tank increases. These solids can clog the soil at the
disposal location and unnecessarily pollute the groundwater or a nearby
stream or lake. Pumping out septic tanks periodically helps to avoid such
problems.
The septage or sludge which is pumped from the tank is a fluid mixture
of partly digested sewage solids and liquids. It has typically been
disposed of in rural areas by discharge into a community treatment facility,
but the distance to such facilities often results in septage being
discharged without control to woodland, farms and streams.
Because septage contains small quantities of nitrogen, phosphorus,
potassium and other trace elements that are nutrients for plant growth, it
can be beneficially used if correctly managed. In this way material that
has been a disposal problem can become an economic resource. There are
various ways in which septage can be reused including composting and
injection or controlled application to land.
The most important requirements for the successful use of septage in
normal farming operations are landowner arrangements, public acceptance,
and a cooperative relationship with municipal officials and regulatory
agencies. Farmers willing to cooperate and use septage in their normal
farming operations must be located and suitable fields selected. Travel
distances and road conditions are important factors to a septage hauler, but
field conditions, crops, and timing of application are more important to the
farmer.
3-28
-------
A septage hauler should have several alternate sites available on which
he can spread the sludge if, for any reason, the preferred site is
unavailable. The number of sites and total acreage depend on the amount of
septage that he expects to haul. Guidelines for septage loadings are
normally provided through the local agricultural extension office and the
state regulatory agency.
Septage should be applied on agricultural land as uniformly as
possible, either in a thin surface application or through subsurface
injection. If it is applied on the surface it should be plowed under within
24 hours to control odors and eliminate nuisance complaints.
The use of septage in normal farming operations may provide an
economical method of disposal for the hauler during serveral months of the
year, but there are extended periods during which other methods of
management and disposal will be required. One alternative would be to
locate one or more municipal wastewater treatment plants that will accept
this material for treatment and final disposal. If haulers cannot make
satisfactory arrangements with a treatment plant, they may have to
construct holding ponds where the septage can be stored temporarily until
conditions are more suitable for agricultural use.
There are many municipalities in EPA Region IV that are spreading sludge
and septage on agricultural lands. The following is a sample of municipal
treatment plants that are involved with the application of sludge to crop
and forest lands:
Augusta, GA
Coneyville and Leitchfield, KY
« Organa, NC
Morganton, NC
Spartanburg, SC
Woodbury, TN
3-29
-------
During the wet weather months when application of dry or wet sludges
cannot be made, anaerobic sludge and septage can be dewatered and composted.
Sludge and septage have been successfully composted using static piles and
windrows to produce a biologically stable product suitable for use in
landscaping, horticulture turfgrasses and on agricultural crops. The
following is a list of treatment facilities which are managing sludge by
composting:
Lexington, KY
Durham, NH
Washington, DC
Beltsville, MD
Manassas, VA
East Richland County, SC
On farms, livestock wastes and domestic wastes have also been used to
produce biogas to heat poultry houses, greenhouses and dairy parlors.
Biogas can also be compressed to methane for fueling farm equipment and
powering electrical generators. Methane cogeneration has also been
successfully used in conjunction with municipal treatment plant anaerobic
digesters. A treatment facility in Los Angeles, for example, is producing
25 megawatts of electricity from this method. In the study area, Henderson,
NC, is recovering methane gas from this type of process.
Sludge and septage have also been used successfully to revegetate
disturbed lands. In Pennsylvania, strip mined areas were successfully
revegetated with a mixture of dewatered sludge cake and composted sludge.
Vegetative covers have persisted for periods up to five years without
deterioration (Sopper, 1984). Similar projects have been completed in
Kentucky and other Appalachian coal fields with improved strip mine spoil
and leachate quality.
The recommended minimum frequency for pumping out septic tanks varies
depending upon the size of the tank, flow of wastewater entering the tank
and the solids content of the wastewater. Assuming a minimum wastewater
3-30
-------
residence time within a tank and assuming a certain percentage of the
retained solids are decomposed, minimum pumpout frequencies can be es-
timated. Table 3-11 lists estimated pumpout frequencies assuming a minimum
wastewater residence time of 24 hours and assuming 50 percent of the solids
are decomposed (digested)., If six people reside in a three bedroom home
with a 900 gallon septic tank, the tank should be pumped at least every 1.3
years. If the same tank serves a family of two, the tank should be pumped
at least every 5.2 years. Smaller tanks need to be pumped more often for the
same household size. Lack of any inspection and maintenance allows
structural deficiencies to go unnoticed and possibly jeopardizes the
absorption system. In septic tanks and pumping chambers bad seals and
cracks which go uncorrected may allow significant amounts of groundwater to
infiltrate and overload the system. Baffles which are no longer functional
or in their proper location may be permitting significant amounts of
undetected solids to pass into the absorption area.
Many current designs are not hydraulically sound in that too little
attention is paid to reducing in-tank turbulence and attenuating peak
discharge rates.
Septic tank designs can be modified so as to produce an inlet and outlet
device which will be efficient and long-lasting in a highly corrosive
environment. Inspections made during the repair process often find baffles
on the bottom of the tank that have deteriorated and fallen off. This
condition then allows grease and solids to flow into the soil absorption
area, possibly clogging the soil.
Septic tanks should be constructed in two compartments or have tanks of
unequal volume installed in series. Initally, these methods result in
better anerobic waste digestion. However, if sludge (which accumulates
more quickly in the first tank or compartment) continues to accumulate
without pumping, a sewage backup will occur. Unless sludge is removed
before a back-up occurs, it can cause solids to flow into the absorption
field, clogging the field and causing failure of the system.
3-31
-------
Inspection ports on septic tanks extended to the ground surface can help
facilitate maintenance checks. Current installation practices encourage
users of septic tanks to forget them, because most are deeply buried
without inspection ports or access manholes. Incorporation of ports or
manholes would serve to continuously remind the users of the location of the
facilities and allow ready access for maintenance. Utilizing cleanouts as
depicted on Figure 3-38 can aid in the location of distribution laterals
and aid in routine maintenance (e.g. flushing).
Wastewater engineering techniques for clusters of establishments,
small communities and centralized systems have more frequent maintenance
needs than do typical on-site systems. Sewers should be flushed and
periodically inspected. Treatment units need at least weekly inspections;
more sophisticated treatment units need even more intense monitoring and
adjustment. Techniques which require energy and/or chemical inputs have
particularly frequent maintenance needs. Types of OMR activities for
cluster, small community and centralized wastewater systems are described
in Table 3-12. These OMR activities are currently best understood and
implemented for the centralized systems, in part because a small number of
trained persons can concentrate on a handful of centralized facilities.
Budget constraints for maintaining numerous small systems and the seemingly
minor effect of a malfunctioning small system contribute to lower prior-
itization of OMR activities for small systems, even though OMR needs are
much more intensive for centralized systems. Operation, maintenance and
repair of small systems deserves more emphasis in terms of budget and
trained personnel than they have received in the past.
3-32
-------
Many current designs are not hydraulically sound in that too little
attention is paid to reducing in-tank turbulence and attenuating peak
discharge rates.
Septic tank designs can be modified so as to produce an inlet and outlet
device which will be efficient and long-lasting in a highly corrosive
environment. Inspections made during the repair process often find baffles
on the bottom of the tank that have deteriorated and fallen off. This
condition then allows grease and solids to flow into the soil absorption
area, possibly clogging the soil.
Septic tanks should be constructed in two compartments or have tanks of
unequal volume installed in series. Initally, these methods result in
better anerobic waste digestion. However, if sludge (which accumulates
more quickly in the first tank or compartment) continues to accumulate
without pumping, a sewage backup will occur. Unless sludge is removed
before a back-up occurs, it can cause solids to flow into the absorption
field, clogging the field and causing failure of the system.
Inspection ports on septic tanks extended to the ground surface can help
facilitate maintenance checks. Current installation practices encourage
users of septic tanks to forget them, because most are deeply buried
without inspection ports or access manholes. Incorporation of ports or
manholes would serve to continuously remind the users of the location of the
facilities and allow ready access for maintenance. Utilizing cleanouts as
depicted on Figure 3-38 can aid in the location of distribution laterals
and aid in routine maintenance (e.g. flushing).
Wastewater engineering techniques for clusters of establishments,
small communities and centralized systems have more frequent maintenance
needs than do typical on-site systems. Sewers should be flushed and
periodically inspected. Treatment units need at least weekly inspections;
more sophisticated treatment units need even more intense monitoring and
adjustment. Techniques which require energy and/or chemical inputs have
particularly frequent maintenance needs. Types of OMR activities for
3-33
-------
TABLE 3-11
ESTIMATED SEPTIC TANK PUMPING FREQUENCIES (IN YEARS)
FOR YEAR-ROUND RESIDENCES
Household Size (No. of people)
Ul
i
Ul
b.
Tank
Size
(gal)
500
750
900
1000
1250
1500
1750
2000
2250
2500
1
5.8
9.1
11.0
12.0
16.0
19.0
22.0
25-0
29.0
32.0
2
2.6
4.2
5.2
5.9
7.5
9.1
11.0
12.0
14 .0
16.0
3
1.5
2.6
3.3
3.7
4.8
5.9
6.9
8.0
9.1
10.0
4
1.0
1.8
2.3
2.6
3.4
4.2
5.0
5.9
6.7
7.5
5
0.7
1.3
1.7
2.0
2.6
3.3
3.9
4.5
5.2
5.9
6
0.4
1.0
1.3
1.5
2.0
2.6
3.1
3.7
4.2
4.8
7
0.3
0.7
1.0
1.2
1.7
2.1
2.6
3.1
3.5
4.0
8
0.2
0.6
0.8
1.0
1.4
1.8
2.2
2.6
3.0
4.0
9
0.1
0.4
0.7
0.8
1.2
1.5
1.9
2.2
2.6
3.0
10
0.3
0.5
0.7
1.0
1.3
1.6
2.0
2.3
2.6
NOTES: The frequency estimates are based on a minimum 24-hour
wastewater retention time and 50 percent digestion of
the solids entering the tank. More frequent pumping
would be needed if garbage disposals are utilized.
Source: Mancl, 1983.
-------
THREADED CAP
PVC PIPING
-CLEANOUT FITTING
NOTE : CLEANOUT VERTICAL RISER
EXTENDS TO SURFACE OR
TO JUST BELOW SURFACE
EXISTING
LATERAL
DRILL LAST
HOLE IN OUTSIDE
SWEEP OF ELBOW
REPLACE
END CAP WITH
STD. 90° ELBOW
INSTALLATION OF
LATERAL CLEANOUT
FIGURE 3-38
-------
cluster, small community and centralized wastewater systems are described
in Table 3-12. These OMR activities are currently best understood and
implemented for the centralized systems, in part because a small number of
trained persons can concentrate on a handful of centralized facilities.
Budget constraints for maintaining numerous small systems and the seemingly
minor effect of a malfunctioning small system contribute to lower prior-
itization of OMR activities for small systems, even though OMR needs are
much more intensive for centralized systems. Operation, maintenance and
repair of small systems deserves more emphasis in terms of budget and
trained personnel than they have received in the past.
3-35
-------
3.5 Enhancement Techniques for Small Wastewater Systems
There are certain engineering techniques that can improve system
performance which would, in all likelihood, not be evaluated when a system
is in need of quick repair. Such techniques, called enhancement techniques
in this report, can be highly cost-effective and implemented either before
a new system is installed or after significant modifications to an existing
system are deemed necessary.
Practices within the home or business that can enhance performance of
any wastewater system include:
use of water saving devices (see Figure 3-39),
avoiding or discontinuing use of garbage disposals,
using grease traps,
separating toilet wastes (blackwater) from other wastewaters
(greywater) (see Figure 3-40),
diverting roof runoff away from wastewater system.
The most common and inexpensive watersaving devices are low-flow shower
heads, low-flush toilets and pressure-reducing valves. Existing shower
heads and toilets can be easily modified to reduce shower and toilet water
use by as much as 60 percent; shower heads and faucets often account for
60 to 70 percent of average daily water use at a typical year-round or
seasonal household. Discontinuing use of garbage disposals and initiating
use of grease traps can be an inconvenience at first. However, reduction of
solids and grease loadings to the wastewater system can reduce wastewater
system maintenance and repair costs, thereby benefiting the homeowner.
Separating blackwater and greywater is far more costly than the other
enhancement techniques utilized within the home or business. This
technique may lessen a problem with hydraulic overloading, but may pose
problems with treatment of the greywater fraction. Toilets which compost or
incinerate wastes with minimal water use are also available. Blackwater-
greywater separation and composting or incinerating toilets have been
tested but not extensively implemented largely because of their relatively
high costs.
3-36
-------
TABLE 3- 12
OPERATION, MAINTENANCE AND REPAIR (OMR) ACTIVITIES FOR
CLUSTER, SMALL COMMUNITY AND CENTRALIZED WASTEWATER TECHNIQUES
CO
-j
Technique
Pumps
Pipelines
Septic Tank
Filters
Other treatment
systems
Underground
disposal
Above ground
land disposal
OMR Activities
Typical Service
Life, Years
Inspection and Lubrication 10 to 20
Flushing 30 to 40
Pumpout 30 to 40
Backwash 20
Operate total system 20
and remove sludge
Monitor from above ground 20
following wet period and
period of abnormal usage
Maintain nozzles 10 to 20
(irrigation)
Monitor wastewater distri-
bution and infiltration
Preferred Minimum
Frequency of OMR Activity
Monthly
Every 2 to 3 years
Typically 1 to 5 years
(see Table 3-10)
Daily to weekly
Daily to weekly
Every 1 to 2 years
Weekly
Discharge to
surface water
Comply with discharge
permit requirements
20
Weekly
-------
The performance of septic tanks, absorption beds on trenches and
irrigated fields can be enhanced with one of a number of techniques, all of
which require design, installation and maintenance:
multi-compartment or multiple septic tanks or other treatment
units in series,
pressure dosing of beds or trenches to evenly distribute
disposed wastewater,
alternating use of two or more beds, trenches or fields
(e.g. on a hillside to allow disposal areas to dry out
periodically),
use of intercepting or curtain drains to reduce infiltration
from surface runoff to disposal area (see Figure 3-41),
fewer and smaller diameter distribution pipes and discharge
holes to promote more even distribution of effluent,
for rapidly permeable coarse-textured soils, e.g.
sands and gravels, a "sandwich" of loam on silt 6 to 18
inches thick included in the total vertical thickness to
enhance wastewater treatment,
shallow placement of disposal pipes (as close as 12 inches
from the soil surface) if the upper layer of soil is
relatively permeable and the water table or bedrock is
3 to 5 feet below the soil surface,
use of distribution boxes in lieu of headers, drop boxes,
serial or step down distribution techniques.
All of these techniques have been tested and effectively utilized at least
on an experimental basis; engineers who have designed such techniques are
available.
In addition, more frequent maintenance of any wastewater facilities
than is minimally recommended (e.g. annual pumpout of septic tanks) and
frequent inspection of facilities can thwart potential problems and
effectively increase service lives of facilities. Systems which are
utilized only intermittently should preferably be inspected each time
their use is reinitiated.
3-38
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3.6 Preferred Design Practices
Public health department professionals, engineers, soil scientists and
sanitarians can more effectively design small systems if certain practices
are followed. Many such practices are not particularly costly in light of
the potential benefits to be gained.
Proper training is an important pre-requisite for any designer. This
includes periodic training updates to assimilate evolving practices. Some
states require individuals to be properly trained before the individuals
can supervise or conduct a system design. Admittedly, quality control of
numerous small system designers can be more difficult than for a handful of
large system designers.
Some of the design procedures which at times are improperly conducted
include:
relying solely on published soils information from
the local county soil survey rather than performing
field tests at the site,
poor site evaluations, including failure to assess impacts of surface
water runoff and internal groundwater movement,
poor soil profile description made by nonqualified personnel
who fail to detect seasonal high water tables as evidenced
by soil discoloration (e.g. gleying or mottling) and who fail
to locate and properly describe restrictive features, e.g. slowly
permeable layers and fractured rock,
improper assessment of the soil's ability to accept and properly
renovate wastewater effluents, particularly, failure to
determine whether or not sufficient soil exists in profiles
having high volumes of rock fragments,
failure to determine the overall site characteristics due to
the lack of sufficient soil testing (either back hoe test
pits or hand auger borings),
failure to consider different effluent quality characteristics
from different types of uses, e.g. restaurants vs residential,
failing to design treatment units and absorption system for
long-term performance. Systems are designed typically by using
3-39
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CURTAIN
DRAIN
FILL
FILL
MATERIAL
PERCHED
WATER TABLE
DRAINAGE PIPE
GRAVEL FILLED ABCVE
HIGH WATER TABLE
NOTE : CURTAIN DRAIN IS USED TO INTERCEPT LATERALLY MOVING
PERCHED WATER TABLE CAUSED BY A SHALLOW,
IMPERMEABLE LAYER.
SOURCE: KENTUCKY CABINET FOR
HUMAN RESOURCES, 1983
CURTAIN DRAIN
FIGURE 3-41
-------
State Regulations and Codes as the sole basis of design;
these guidelines are often only meant to serve as guidelines for
establishing minimum requirements,
failure to correlate soil characteristics with permeability
test results. Differences in percolation test hole construction
and presoaking techniques lead to variable test results.
Designers should use percolation test results with care,
particularly when working with fine textured soils (e.g. loams
and clay loams). Test results may not be truly representative,
because soil percolation tests are conducted with relatively
clean water, free of solids and nutrients. Designers should be
conservative with establishing wastewater loadings and consider
the long term acceptance rate of the soil.
failure of designers to fully adapt a wastewater system to the
site. Errors are made with mismatching absorption system geometry
with site conditions which often results in localized overloading
of the soil and possible groundwater mounding and flooding.
designers sometimes fail to understand the impacts of soil
characteristics relating to installation. Some designers fail
to consider the use of more permeable soil horizons for placement
of wastewater distribution networks.
improper installation or construction of the sewage facility
in an area not previously tested or with insufficient separation
from water supplies such as wells, springs or other water ways,
failure of designers to consider techniques which can be implemented
in the field to make gravity-feed systems perform better (e.g.
specifying discharge hole diameters and spacing for wastewater
distribution network),
failing to project flow inputs for the life of the proposed facility,
o not matching recommended design parameters to the prescribed field
conditions (e.g. size of absorption area or distance to water
supply well or spring),
improper siting (e.g. upslope of a water supply well or within
a poorly drained soil).
Failure to consider variations in effluent quality from
residential applications to commercial/industrial applications.
3-40
-------
Many of the problems that result from improper design procedures can be
avoided without incurring large expenses. The recommended values shown in
Tables 3-2, 3-5 and 3-8 should be followed. In addition, certain design
techniques can be followed such as:
considering modifications in wastewater applications techniques
for gravity systems with one of the methods described in Section
3.5,
providing cleanout access to sewer pipes at periodic intervals
(usually every 100 feet at a maximum),
avoiding sewer pipe bends of greater than 45 degrees ahead of
the septic tank or other type of treatment unit,
qualified supervision of design procedures by a trained local
health department staff,
properly conducted soil permeability testing often allowing 24-36
hours of presoaking for fine textured soils (e.g. clay loams),
comparing measured soil percolation test results with published
soil permeabilities for U.S.D.A. established soil series,
performing comprehensive soil testing to more accurately
describe soils and potential restrictive features in the proposed
absorption area.
To adequately evaluate suitability of soil conditions for a proposed soil
absorption system requires the determination of the presence and location
of restrictive soil features such as slowly permeable sub soil layers,
fractured rock and high groundwater elevations. A detailed description of
recommended procedures for carrying out an adequate site soils survey has
been included as Appendix II-A to this volume.
Conversely, there are site conditions for which use of certain
wastewater techniques should not be made due primarily to public health and
environmental constraints. Soils which do not have a well-structured and
drained profile for at least 2 to 4 feet should not ordinarily be used for
soil absorption treatment and disposal systems. However, some types of
3-41
-------
systems can be constructed on these marginal soils with special siting,
design and construction as illustrated on Figures 3-11 through 3-18. In
terms of costs and benefits, the avoidance of adverse impacts produced when
untreated wastewater rises to the soil surface or reaches a water supply may
be well worth the extra cost of instituting a cluster or other type system
in locations where soil or other conditions are not suitable to on-site
disposal. Such areas should be designated and enforced as not being usable
for land disposal techniques before systems are designed and installed, if
possible. Public management and authority can help greatly to enforce
restrictions on use of land disposal techniques.
3-42
-------
3.7 Evaluation of Alternative Engineering Techniques
The engineering techniques discussed in Sections 3.2 through 3.5 can be
utilized for both new development and for rehabilitation of existing
wastewater systems. In either case the objective is to select the most
cost-effective alternative which will reliably remove harmful constituents
from the wastewater and produce an effluent of sufficient quality to be
disposed of to either the land or water without causing environmental
quality or public health impacts.
A reasonable method for selecting the most appropriate engineering
technique for a given community would be to consider alternatives in order
of increasing complexity. The least complex techniques are typically least
expensive, are most straight-forward to install, and require the least
amount of OMR. However, the simplest techniques will not be appropriate for
all communities. In some locations more complex systems may be needed to
ensure adequate performance because of factors such as community population
density, growth projections, or natural features. The system must still be
within the financial and operational capability of the owner.
Figure 3-42 illustrates a method which may be used for selecting
engineering techniques for new development by considering the most basic
systems first. Simple individual on-site techniques are often the least
costly wastewater management methods (U.S. EPA, 1982b as an example). These
simplest techniques should be evaluated first, particularly for sparsely-
populated areas. The most critical design parameters for any land treatment
arid disposal system are:
depths to water table and bedrock,
size of absorption area given soil permeability, and peak
wastewater flows,
« land slope,
o distances and flow potential to water supply, stream or adjacent
property, and,
lot size.
3-43
-------
RECOMMENDED METHODOLOGY FOR SELECTING
PREFERRED ENGINEERING TECHNIQUES
FOR NEW SYSTEMS
WASTE
REVIEW INFORMATION
PREV'OJSLV WRiTTEN
ABOUT THE SITE
[EG SIZE, WATER SUPPLY)
INTERVIEW
LANDOWNER &
SITE SURVEY
INITIATE
LIST THE MOST FEASIBLE
TECHNIQUES BASED ON
ESTIMATES OF COST AND
PUBLIC HEALTH CONSTRAINTS
!E G CENTRALIZED WATER
SUPPLY)
FINAL INSPECTION,
SYSTEM BURiAL
AND START-UP
OPERA! ON,
w«, '.TENANCY
AND REPfliR!DM=,
FIGURE 3-42
-------
Sources for information on these constraints and constraints related to
public wastewater facilities are presented in Table 3-13. Any of these
constraints can eliminate consideration of on-site systems based on state
public health and environmental quality regulations. If such state
guidelines do not exist, guidelines from neighboring states should be
utilized. The engineering analysis of on-site systems for any estab-
lishment requires an evaluation of site constraints and prevailing siting
regulations. Table 3-14 lists five key site constraints and the various
types of on-site techniques which will be implemented under various
constraints. Where an "X" is not shown on Table 3-14, that on-site
technique is not considered implementable.
If on-site techniques cannot be implemented or if needed modifications
make on-site systems costly, then larger-scale cluster and small community
systems need to be evaluated. If the establishment is within a reasonable
distance of a municipal sewer system, then connection to that system should
also be evaluated.
Ideally, all potentially suitable engineering techniques should be
evaluated simultaneously for each of four basic factors:
costs, in terms of present worth and annual costs with or
without a grant or loan,
impacts on the environment,
operation of the technique, and
implementation of the technique.
Considerations related to each of these four factors are presented in
Tables 3-15 through 3-18. Clearly, the process of evaluating various
engineering techniques can be quite complex. Many parameters can be
involved. Cost is the only factor that can be quantified, although the
evaluator must be sure that each quantified dollar amount is suitable to be
compared with other costs presented. Definitions and methodologies for
3-44
-------
evaluation analyses are presented in other EPA guidance documents (U.S.
EPA, 1980d and U.S. EPA, 1982a). Judgment is always required when costs,
impacts, operation and implementation are being compared.
Conceivably, all wastewater engineering techniques except simple on-
site systems could be too costly or not desirable for other reasons. If this
type of conclusion is made, some options still exist:
install the wastewater system (with proper inspection and
periodic maintenance) and avoid use of adjacent water supply
wells, or
use holding tanks for the short-term time periods when the
on-site wastewater system fails.
Figure 3-42 presents a methodology which has a number of steps (in
squares) and decision points (in diamonds) in order to allow all feasible
wastewater techniques to be evaluated. Too often affordable, suitable
techniques are not evaluated only because they were never considered. If a
planner properly utilizes Figure 3-42, that planner must consider on-site,
cluster, small community and centralized wastewater techniques. Steps
that can be difficult in Figure 3-42 include defining which systems are
"applicable" and then weighing the trade-offs amongst all "applicable"
techniques. The planner should not need to assess costs, impacts, operation
and implementation of more than three or four types of systems, but defining
those that are most "applicable" should not be made arbitrarily. Appli-
cability of all but the most complex and costly on-site techniques is based
primarily on site conditions presented in Table 3-13. Applicability of
cluster, small community and centralized systems depends largely upon costs
for both installation and operation compared to the benefits of avoiding
on-site techniques. Weighing the trade-offs among the "applicable" should
involve non-judgmental, co-equal consideration of costs, impacts, operation
and implementation.
3-45
-------
TABLE 3-13
CONSTRAINTS WHICH MAY AFFECT THE SELECTION
OF APPROPRIATE ENGINEERING TECHNIQUES
Type of Facility
On-Site Systems
and community land
disposal sites (for
wastewater and sludge)
Sewers and treatment
plants
Factor to Consider
Soil characteristics and permeabil-ity
Depth to water table
Depth to bedrock
Land slope (e.g. concave or convex,
percent slope)
Costs to control
runoff through the site from
upstream locations
Separation distances (wells, surface
waters, springs, terraces, property
boundaries, buildings subsurface
drainage)
Water supply well (& and wastewater
system location in relation to
predominant direction and speed
of groundwater movement
Land area available as compared to
land area required to properly
handle loadings
Depths to bedrock and water table
(important to assess costs)
Land slope
Available land area as needed for
r ight-of-way
Sources of Values
Based on state guidelines
Dependent upon site
conditions
Based on state guidelines
Based on site conditions
Depends upon number of per-
sons served, soil charac-
teristics, state loading
guidelines and local
land use.
Dependent upon local con-
ditions.
H
Dependent upon local con-
ditions
3-46
-------
TABLE 3-14
VARIOUS SITE CONSTRAINTS WHICH WILL
AFFECT SELECTION OF DISPOSAL TECHNIQUES
Method
Trenches
Beds
Pits
Mounds
Fill Systems
Sand-Lined
Trenches or
Beds
Artificially
Drained
Systems
Evaporat ion
Infiltration
Lagoons
Evaporation
Lagoons
(lined)4'5
ET Beds
or Trenches
(lined)4'5
ETA Beds
or Trenches4
Site Constraints
Soil Permeability Depth to Bedrock
Very
Rapid
X
X
X
X
X
Rapid-
Moderate
X
X
X
X
xi
X
X
X
X
X
X
Slow-
Very Slow
X2
X
xi
X2
X5
X
X
X
Shallow
and
Porous
X
X
X
X
Shallow
and
Nonporous
X
X
X
X
Deep
X
X
X
X
X
X
X
X
X
X
X
Depth to
Water table
Shallow
X
X
X
X
X
Deep
X
X
X
X
X
X
X
X
X
X
Slope
0-5%
X
X
X
X
X
X
X
X
X
X
X
5-15%
X
X
X
X
X3
X
X6
X
15%
X
X
X
X3
X3
X
Small
Lot
Size
Xi
X
X
X4
X4
X
Only where surface soil can be stripped to expose sand or sandy loam material.
2 Construct only during dry soil conditions. Use trench configuration only.
3 Trenches only.
4
5
6
Flow reduction suggested.
High Evaporation potential required.
Recommended for south-facing slopes only.
ET-evapotranspirat ion
ETA-evapotranspiration and absorption
X means system can function effectively
with that constraint.
-------
TABLE 3-15
COSTING CONSIDERATIONS
Year(s) of installation for future facilities. Staged construction merits
evaluation
Utilize local labor rates and equipment costs as much as possible. These
rates and costs should be comparable by being consistent in terms of
inflation and regional cost variations, and they should also be as
up-to-date as possible
Costs for facilities with different service lifes can be compared by taking
into account salvage values at the end of a designated planning period
(usually 20 to 30 years in length)
Useful lifes of existing and possible future facilities need to be quantified
The interest rate for estimating future costs should be up-to-date. If a
particular type of low-interest loan is realistically available, such a
low interest rate could be factored into the calculations
Capacities for future development should be based on approved state, regional
or county population projections. Assumptions about reserve capacity for
future connections to service lines can be difficult to make and controversial
In planning for a facility, may want to consider that grant eligibility varies
from component to component of that facility
Land may need to be acquired or leased
Completed cost estimates cannot be assumed to have an accuracy of better
than plus or minus 5 to 10 percent, particularly for future costs related
to future development.
3-48
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TABLE 3-16
ENVIRONMENTAL FACTORS THAT ARE IMPORTANT
IN THE SELECTION PROCESS
Types of Impacts
Population and Land Use
Groundwater and Surface
Water Resources
Biological Resources
Management of-systems for future establishments
Management of systems for seasonal vs. year-round
residences and tourist businesses
Availability of current land use information
Projected effects of public sewers on land use patterns
(e.g. effects on prime agricultural lands)
Potential for development of floodplains, wetlands,
prime agricultural lands
Projected effects on potable groundwater supplies
particularly due to land disposal of wastewater
Projected effects on uses of local and downstream
surface waters (e.g. recreation, water supply, fish
and wildlife)
Wasteload allocations and discharge treatment requirements
of state agencies
Effects of installing sewer lines and treatment facilities
due to runoff during construction, including stream
crossings and construction near water courses
Conditions of springs and water supply well casings and
proximity to wastewater facilities
Evaluation of methods to reduce adverse impacts on
water quality
Presence of endangered or threatened species and projected
effects of wastewater facilities
Effects on hunting and fishing
Effects due to construction activities
Economics and Employment
Archaeological-Historical
Resources
Odor
Availability of water and sewer facilities for industry
and/or tourist development in relation to availability
of other public services
Effects on recorded sites
Evaluation,of methods to avoid recorded sites
Methods to manage any potential odor problems due to
system malfunctions.
3-49
-------
TABLE 3-17
OPERATION CONSIDERATIONS FOR ALTERNATIVE
WASTEWATER ENGINEERING SYSTEMS FOR RURAL AREAS
ADVANTAGES
OJ
I
en
o
Individual On-Site Systems
Systems are not complex to design
install or maintain.
Maintenance is only needed every
1 to 5 years.
Better sitings, designs and
installation procedures extends the
use of both inground or above ground
absorption systems over valuable soil
and site -conditions.
Energy and chemical needs are
minimal.
Cluster and
Small Community Systems
Better treatment of wastewater
can be provided than from on-site
systems.
Wastewater from households with
a density greater than three house-
holds per acre can be properly
treated and disposed.
Discharges of treated waste-
water to surface waters, if per-
mitted, can be operated regardless
of climate conditions.
Connect to an
Existing Centralized System
Only relatively infrequent
inspection and maintenance of
facilities is required.
Sewers are neither sophisti-
cated nor complex to install unless
sufficient depth to bedrock is not
available.
Maintenance access to larger
sewers is better than for small
community sewers.
DISADVANTAGES
Lot sizes less than one-third of
an acre on lots with shallow soil
depths or slowly permeable soils
should not be utilized.
A large number of systems need to
be maintained.
Experience with mound systems for
use in marginal soils is limited in
the EPA Region IV states.
Periodic maintenance cannot be
enforced without a managing entity
that has enforcement powers.
Inspection to determine cause of
failure and even whether a failure is
occurring is difficult, because most
or all of the system is beneath the
soil surface.
Weekly or more frequent oper-
ation and maintenance are required.
Additional qualified staff may be
needed.
Discharge permits and effluent
monitoring may be needed.
Shallow depth to bedrock can
inhibit sewer installation.
Energy and chemical usage can
be much greater than for on-site
systems; standby supplies are also
needed.
More sludge needs to be pro-
cessed and disposed than for on-
site systems.
Costs are often quite high
for sewer installation.
Energy usage can be parti-
cularly large.
Additional treatment capacity
at the municipal wastewater treat-
ment plant is required.
-------
TABLE 3-18
IMPLEMENTATION CONSIDERATIONS FOR ALL
TYPES OF WASTEWATER SYSTEMS
Local, State and Federal
guidelines or requirements
Individual on-site system design and installation
requirements (local or state)
Discharge permits for treatment plants and
corresponding treatment requirements (state)
Consistency with regional plans and local land
use policies
Financing
Federal, regional or state grant eligibility
and administrative requirements (see Chapter 5)
Loan eligibility and administrative requirements
(see Chapter 5)
Assessing ability to pay given existing debt
and grant loan eligibility
Public and agency perception
and involvement
Ability and willingness to pay for local share
Access to private on-site systems for maintenance
and repair
Public perception of impacts on water supply,
public health and the natural environment
Feasibility of long-term use of private lands
for community wastewater or sludge disposal
System management
Designation of the agency responsible for
installation, operation, maintenance and
repairs.
Value and content of a separate management entity
with enforcement authority (see Chapter 4)
3-51
-------
Certain county, regional and state professionals can likely assist in
providing specific types of information important to assessing types of
wastewater facilities. Such professionals include:
town or county water, sewer and solid waste departments,
county health department and sanitarians,
local or county planning agency (land use information) and
tax assessor (lot characteristics),
state wastewater engineers and planners, and perhaps,
university professors with pertinent expertise.
Once the preferred technique is selected, additional field work should
be part of the design effort. Such follow-up field work and design could
uncover problems or inconsistencies not addressed when all the "applicable"
techniques were evaluated. If problems and inconsistencies arise, some re-
evaluation should be conducted.
Existing wastewater systems can be evaluated to select the preferred
method for rehabilitation using a methodology quite similar to the
methodology just presented for new systems. Figure 3-43 illustrates a
useful methodology.
To begin consideration of rehabilitation techniques requires that a
need for rehabilitation has been discovered. Existing on-site facilities,
in particular, can cause groundwater or surface water contamination
without being noticed. Periodic water quality monitoring activities
usually cannot result in pinpointing sources of water pollution. There-
fore, unless complaints are received from homeowners or water companies
about contaminated wells, pollution can continue unnoticed for years,
particularly from wastewater facilities placed in coarse-grained soils.
County health departments are encouraged to perform field inspections and
tests of on-site systems that have been utilized for more than 20 years.
The decision points in Figure 3-43 (in diamonds) progress from least
costly to most costly methods of rehabilitation. Both the wastewater and
3-52
-------
RECOMMENDED METHODOLOGY
FOR SELECTING PREFERRED
SYSTEM REHABILITATION TECHNIQUES
IS
CURRENT
SYSTEM PERFORM
ING ADEQUATELYI8ASED
ON FIELD
SSMEND
CONTINUE
EXISTING
OUR
COULD
PROPER OMR
OR NEWER FACILITIES
CORRECT
PROBLEM
INSTITUTE
PROPER OUR OR
INSTALL NEW
HARDWARE
COULD
SOME STRUCTURAL
MODIFICATIONS
CORRECT
PROBLEM
INSTITUTE
STRUCTURAL
MODIFICATIONS
SCREEN ALL REASONABLE
ON SITE DESIGN
TECHNIQUES
(STRUCTURAL AND
NON-STRUCTURAL)
COULD
OTHER TECHNIQUE
AT THE SAME SITE
SOLVE THE
PROBLEM
EVALUATE AND
INSTITUTE NEW
TECHNIOUE(S)
ON SITE
SCREEN ALL
REASONABLE OFF-
SITE TECHNIQUES
COULD
A CLUSTER
OR SMALL COMMUNITY
SYSTEM SOLVE
THE PROBLEM
EVALUATE AND
INSTITUTE NEW
CLUSTER OR SMALL
COMMUNITY
SYSTEMS
COULD
CONNECTION TO
A CENTRALIZED SYSTEM
DABLY SOLV
PROBLEM
EVALUATE AND
INSTITUTE
CONNECTION TO
A CENTRALIZED
SYSTEM
EVALUATE
MODIFYING WATER
SYSTEM RATHER THAN
WASTE WATER SYSTEM
REVIEW ALL
AVAILABLE
WASTEWATER
TECHNIQUES
EVALUATE USE OF
HOLDING TANKS IF
PROBLEMS ARE
SHORT-TERM
SELECT THE
MOST SUITABLE
TECHNIQUE(S)
FIGURE 3-43
-------
water supply systems need to be evaluated for rehabilitation; it may be
advantageous to modify an existing well rather than modify the wastewater
system. Proper OMR (Operation, Maintenance and Repair) and replacement of
small pieces of equipment are less costly than structural modifications and
use of other techniques. Decisions about whether a certain form of
rehabilitation can correct a problem need to be made by qualified
sanitarians or sanitary engineers. Once the rehabilitation is implemented,
a check needs to be made to verify in the field that the problem was indeed
corrected as a result of rehabilitation.
If no methods for rehabilitating the wastewater system can solve the
problem, then some other change is needed. Perhaps, for example, holding
tanks can be utilized during a certain season or during wet periods. While
such changes may not be totally desirable, they may be preferred over
allowing the original problem to continue.
Many engineering techniques are available for managing wastewater and
sludge generated at individual establishments, clusters of establishments
and small communities. Most of these engineering techniques are tech-
nologically simple; problems usually arise due to improper design and
installation or excessively infrequent operation, maintenance and repair.
Many problems can develop with small wastewater systems, however, most
remedies, like the techniques; themselves, are not particularly difficult
to implement. The techniques and problems are all examined in this chapter.
In selecting which techniques to implement at newly-developed lo-
cations, four basic factors should be evaluated: costs, impacts, operation
and implementation. Any one of these four factors can rule out use of
certain techniques. Those responsible for implementation typically con-
sider costs and obstacles to implementation more than the other basic
factors, although all four basic factors deserve careful attention.
In rehabilitating existing systems, the simplest, least costly options
should be evaluated first. Careful rehabilitation can extend the life of a
3-53
-------
system in a cost-effective manner, even if rehabilitation costs seem high at
the time.
The engineering techniques for designing, installing and maintaining
small wastewater systems are neither financially burdensome nor tech-
nologically complex. Therefore, the key to successful use of small systems
is adequate involvement and guidance from wastewater professionals whose
objective is to provide safe, inexpensive and environmentally-sound waste-
water systems.
3-54
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
yxv-*--i;^X/ r1 .' -A
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-1
Septic Tank
-------
DESCRIPTION SYSTEMS
MANUFACTURER
mtel
vent
outlet
-sanitary tee
luo Cor.oartncnt Settle TanL
Precast septic tanks up to 2,000 gallons in
capacity are usually available directly from a
local concrete products company. Large
septic tanks are also built on-site by local
contractors.
Plastic septic tanks - Hancor, Inc., Findley,
OH
COMPONENTS
CONTACTS
Concrete fiberglass or plastic circular or rectangular tank
Minimum detention time - 24 hours
Surface Area to depth ratio 2:1
Length to width ratio 3:1
Inlet and outlet protection with baffles or tees
Compartments 1 or 2; Two compartments with the first from 1/2 to 2/3 the
total tank volume provide better treatment
EXAMPLES OF USAGE
Septic tanks ranging from 750 to 1,200 gallons in capacity are used in
typical three-bedroom residential sewage treatment systems. Septic tanks
connected in series can be used to treat higher waste volumes or to improve
anaerobic digestion of small residential waste flows.
Local concrete products companies, septic
tank installors and fabricators.
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-2
Aerobic KVistew^ter Treatment
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Source: Boyle and Otis, 1979.
K.istcrn linvlronncnt.il Controls, Chustcrtuwn,
Ml)
Nnyadte Sciences, Inc., Clarks Summit, I'A
Transamcrican UeLaval, Inc., Covington, KY
Jet, Inc., Cleveland, OH
Owens Manufacturing and Specialty Co.,
Lafayette, LA
Norweco, Inc., Norwalk, OH
Cromaglass Corp., Wiiliamsport, PA
Hycor Corp., Lake Bluff, IL
Bi-A-Robi Systems, Inc., Hamlin, PA
Manolf, Inc., Clearwater, FL
Economy Tank Co., St. Albans, WV
COMPONENTS
CONTACTS
Tank (concrete, plastic or fiberglass) media
Aeration equipment - blower, diffusers
Clarifier
Controls and alarms
Trash trap or septic tank
EXAMPLES OF USAGE
Extended aeration batch and continuous flow
Fixed film - rotating biological contactor
These units are f requently used to treat flows from individual resi-
denses, clusters, school and mobile home parks. Kifluent can be disin-
fected and discharged to lands or surface waters.
Local Health Department Officials
Boyd County, KY
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure J-3
Sand I'lltration
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Top Si
Drainage
Inspection Manhole
and Disinfection
Contact Tank
(If Required)
Profile
Graded Gravel V4" to 1 V
Perforated or Open
Joint Pipe, Tarpaper
Over Open Joints
Source: Salvato, 1932.
COMPONENTS
Pretreatment Unit
Sand filter constructed in an excavation lined with an impermeable liner
Underdrains and distribution piping consisted of perforated pipe surrounded
in gravel envelope
V
f
Reeirculation tank (optional) and flow splitter - recirculating sand filter
Intermittand sand filters - buried or free access J
EXAMPLES OF USAGE
Sand filtration units provide excellent treatment of septic tank and
small aerobic treatment units. High level treatment can be achieved
from recirculating sand filters. These units treat flows typicajly
ranging from 400 to 10,000 (1PD. Units have been used for residential
installation (new and repair), mobile home parks, recreation centers ami
sma.11 school s .
MOB c sand fiLtration unit components, tanks,
piping* sand, and gravel snpplled locally.
Reeirculation tanks, if used, utilize sewage
effluent pumps and controls supplied by
previously referenced pump manufacturers
CONTACTS
A. R. Rubin, N.C. State University, Raleigh,
NC
Sadieville, KY
Madison, NC
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-4
Disinfection
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
FLOM DIAGRAM -
1 ffltii nt from Ai'
Unii/Septu Tank .i
Sand Filter
Discharge
D1SINFKCTION METHODS
Source: U.S. EPA. 1979.
Cltlurinators
Capital Controls Co., Inc. (Colnur, PA)
Cheminler-Kenlcs, Inc. (Dayton, OH)
Chlorinators, Inc. (Jensen Beach, FL)
Fischer and Porter Co. (Warninster, PA)
Wallace and Tiernan Div., Pennwalt Corp.
(Belleville, NJ)
Sanuril, Diamond Shamrock (Chardon, OH)
Various chemical companies supply chlorine or
iodine.
Ultraviolet Irradiation units
Capital Controls Co., Inc. (Colmar, PA)
Katadyn U.S.A., Inc. (Potomac, MD)
Portstar Div., Ultrasonics Research, Inc.
(Jericho, NY)
Pure Water Systems, Inc. (Fairfield, NJ)
COMPONENTS
CONTACTS
Dry feed chlorinators and contact chamber, or
Iodine saturator with pump and holding tank, or
Ultraviolet disinfection unit with controls, surge tank, and pump.
EXAMPLES OF USAGE
Gravity fed tablet chlorination units are in widespread use due to simple
construction, operation, and maintenance. Properly maintained dry-feed
chlorinators, iodine saturators and ultraviolet light units have been
shown to provide consistently high levels of disinfection for small waste
f 1 ows. Ozouu Is another disinfeetant, hut its use at sinal 1 t realiiK*nt
facilities In Urn United Stales is extremely limited.
Local and State Health Department
Officials and equipment manufacturers
(See Appendix II B for a list of state health
department contacts.)
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-5
Holding Tank
-------
DESCRIPTION OF SYSTEMS
Holding Tank - A watertight
tank which receives and re-
tains sewage for ultimate
disposal at another location.
£ CONCRETE
MOLDING TANK
COMPONENTS
Minimum Tank Size - 1,000 gallons; approximately 1 week storage
Alarm System - Audio/visual such as an alarm mounted in a house and cali-
brated mechanical float device.
EXAMPLES OF USAGE
Sealed tanks which retain from typically 1,000 gallons or more from small
flow residential dwellings such as seasonal/vacational units. Can be
used in locations unsuitable for other sewage treatment and disposal units.
MANUFACTURER
Holding Lank (plugged septic tank), alarm
system fabricated or supplied locally
CONTACTS
County and State Health Department Officials
and local contractors
(See Appendix II_B for a list of state contacts.)
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-6
Wastewater Containment
Privy
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Privy - A tank designed to
receive sewage where water
under pressure is not uti-
lized.
\. Source: Pennsylvania D.E.R., 1983.
COMPONENTS
EXAMPLES OF USAGE
Stable - weatherproof super structure; ventilated and insect proof
Concrete holding tank with cleanout
Grading to control surface water runoff
Scaled tanks or vaults capable of storing sanitary waste from small flow
residential, seasonal or vacation tyjxi dwellings. Privies can be utilized
in areas unsuitable Cor other suwagu treatment and disposal techniques.
Privios constructed from materials locally
supplied
CONTACTS
County and State Health Department Officials
Installers/Contractors
(See Appendix II-B for a list of state health
department contacts.)
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-7
Siphon
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
SIPHON SPECIFICATIONS:
Diameter
Max. Discharge
Ave. Discharge
Min. Dudwrge
Low Water Level
High Water Level
Drawdown Depth
Siphons are typically installed in smaller
concrete tanks and even modified septic
tanks by local contractors. Siphon compo-
nents are in kit form and assembled in the
tank.
Fluid Dynamics Company (Boulder, CO)
COMPONENTS
CONTACTS
Trap
Corrosion resistant bell or dome with vent piping
Discharge and overflow pipes
Tank design volume and reserve, concrete
Alarm, high water
EXAMPLES OF USAGE
Dosing of soil absorption systems on sloping terrain. Three feet
elevation difference between siphon high water level and siphon discharge
line. This is a wastewater distribution technique for beds, mounds,
and trenches.
Local contractors and sanitarians site and
install siphons and sloping sites for
wastewater distribution.
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-8
Pumping Tank
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Pumping tank locally supplied
Pumps and Controls are supplied by numerous
manufacturers and suppliers.
J
COMPONENTS
Tank - sufficient capacity to accommodate design flow plus 1 to 1*5 days
reserve capacity
Submersible sewage effluent pump
Sealed mercury float switch
High water alarm system audio/visual
Sealed adjustable water level controls
CONTACTS
EXAMPLES OF USAGE
Pressure distribution/dosing of wastewater effluents and lifting effluent
to higher elevations where more suitable soil has been located for indi-
vidual and cluster size sewage facilities.
Local Health Departments and Contractors
1984 Public Works Manual (200 S. Broad St.,
Ridgewood, NJ; Phone (201)445-5800)
Water and Wastewater Equipment
Manufacturers Assn., Inc. (P.O. Box 17402,
Dulles International Airport, Washington, DC
20041; Phone (703) 661-8011)
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-9
Soil Absorption
Trenches
-------
DESCRIPTION OF SYSTEMS
SOIL ABSORPTION TRENCHES
"*7&:
tiss-1-
SLUDGE
SEPTIC TANK
f
orsmeuTiOH '
BOX ,.
p^H
f-TlLE DRAINAGE LINES
L ^
~I ^-ABSORPTION TRENCHES
r
ABSORPTION FIELD
(PLAN)
COMPONENTS
EXAMPLES OF USAGE
1,000-gallon 1 or 2-compartment septic tank with 2:1 or 3:1 length to
width ratio and a 2:1 length to liquid depth ratio
Gravel lined trenches; 6" minimum depth
Laterals, perforated 3" or 4" diameter plastic pipe
Multi outlet distribution box
Single family residential lots with suitable space for construction of a
primary and replacement system. Trench system can easily require 5,000
ft2 of surface area for installation in addition to satisfying horizontal
isolation distance requirements.
MANUFACTURER
Septic tank, distribution or drop boxes,
gravel solid and perforated piping supplied
locally
CONTACTS
County and State Health Department Officials
Local Installers/Contractors
(See Appendix II-B for a list of state contacts.)
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-10
Soil Adsorption
Seepage Bed
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
2-4'mmririuin sinJuMe soil '
I -42105'
Source: Pennsylvania DEU, 1933.
COMPONENTS
Septic tank, distribution box (or closed
loop) gravel,, perforated pipe and other
material supplied locally.
CONTACTS
1,000 gallon 1 or 2 compartment septic tank,2:1 or 3:1 length to width
ratio, 2:1 length to liquid depth ratio
Excavated bed of 300 to 3,000 ft. of bottom area - lined with a minimum of
6" of gravel or crushed stone
Laterals, perforated 3 or 4" diameter
Distribution box for gravity distribution; pumps or siphon for pressure ,
distribution J
EXAMPLES OF USAGE
Single or multiple family dwellings or clusters having permeable soils and
space limitations which preclude the use of trenches.
County and Local Health Department Officials
Contractors
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-11
Soil Absorption
Mound
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Pretreatment unit septic tank or aerobic unit
Filter Material - medium sands with 1 foot minimum depth
Crushed Stone - sand/sandy loam mixture
Crushed Stone Aggregate - 3/4 - 2*5 inches, 9 inches deep
Distribution Network - small diameter (1-3 inches) pipe
Loamy Topsoil - 1*5 feet deep at cap, 1 foot on sides
EXAMPLES OF USAGE
Allows for soil absorption on shallow (2 feet minimum) and slowly per-
meable soils. Long and narrow mounds with 3:1 downslopes highly recom-
mended. Large waste flows may require multiple mounds.
Constructed by local contractors-
CONTACTS
Madison County, NC Health Department,
Mike Bradley
Bobby L. Carlile, Raleigh, NC
James C. Converse, University of Wisconsin,
Madison, WI
Richard J. Otis, Rural Systems Engineering,
Madison, WI
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-12
Soil Absorption
Trenches Operated in Parallel
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Source: Pennsylvania DER, 1983.
COMPONENTS
1,000-gallon, 1 or 2-compartment septic tank with. 2:1 or 3:1 length to
width ratio and a 2:1 length of liquid depth ratio
Gravel lined trenches; 6" minimum depth
Laterals, perforated 3" or 4" diameter plastic pipe
Multi outlet distribution box
EXAMPLES OF USAGE
Single family residential lots with suitable space for construction of a
primary and replacement system. Trench system can easily require 5,000
ft^ of surface area for installation in addition to satisfying horizontal
isolation distance requirements.
Septic tank, distribution or drop boxes,
gravel and perforated pipe supplied locally
CONTACTS
County and State Health Department Officials 1
Local Installers
(See Appendix II-B for a list of state contacts.)
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-13
Soil Absorption
Distribution of Effiuent
With Drop Boxes
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
DROP BOXES
\. Source: Kentucky Cabinet for Human Resources, 1982.
COMPONENTS
Pretreatment unit
Drop boxes
Trenches - see separate Fact Sheet
EXAMPLES OF USAGE
Residential and other small flow applications on sloping sites. Waste-
water can flow by gravity or be lifted by pumps to higher elevation
absorption areas.
Pretreatment units, drop boxes, distribution
piping, and gravel supplied locally.
CONTACTS
State and County Health Department Officials
(See Appendix II-B for a list of state contacts.)
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-14
Soil Absorption
Subsurface Sand Filter
Without Under Drains
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
EXCESSIVE ROCK
FRAGMENTS OR
CLAY LAYER
^CONCAVE -;.-.
FILL SANDY >
- FILL ...-;:
Treatment unit, distribution piping, sand
and gravel supplied locally.
COMPONENTS
CONTACTS
Pretreatment, e.g., septic tank
Minimum of 1 foot of clean medium sand placed in the zone which is
either slowly or excessively permeable.
Distribution network - gravity or pressure
EXAMPLES OF USAGE
Utilize in areas with soils that are excessively permeable due to high
volume coarse fragment content. This system can also be used where a
slowly permeable soil horizon exists at depths of one to four feet.
Local Health Department Officials
These systems are widely used within the
study area
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-15
Soil Absorption
Filled/Built Up Area
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
!"-l8" SUITABLE SOU.
RESTRICTIVE HORIZON
GROUNDWATER
ROCK
SLOWLY PERMEABLE SOIL
COMPONENTS
Imported loamy, sandy loam soil in place long enough so that natural
permeability has been restored
Perforated laterals in stone/gravel aggregate
Supply distribution system - gravity or pressure
Pretreatment unit (septic or aerobic unit)
EXAMPLES OF USAGE
Can be utilized in areas where there is insufficient natural soil to
provide sufficient wastewater rennovation or areas where shallow depths
to restrictive features like clay pans or fracturered rock exists.
Septic tank or aerobic treatment unit,
distribution-piping and fill material locally
supplied.
CONTACTS
Madison County, NC Health Department, Mr.
Hike Bradley
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-16
Soil Absorption
Low-Pressure Pipe
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
,- SUPPLY y-SMALL DIAMETER
/DISTRIBUTION /LATERAL l|*TOR LARGER
/
K .!'
_V I '-WALL
,OLE SOIL4 2-1
COMPONENTS
Two-Compartment septic tank
Pumping chamber (tank) with sewage effluent pump or siphon
Supply distribution pipe
Small diameter lateral, IV on larger with evenly spaced small diameter
holes typically 3/16" to 3/8",located in shallow gravel lined trenches
J
^\
EXAMPLES OF USAGE
Residential and other small flow applications where suitable soil and
site conditions exist for soil absorption. System provide excellent
wastewater distribution and utilize upper more permeable soil horizons
for absorption.
y
"^\
Septic tank, pumping tank, gravel and
piping supplied locally. Pump or siphons
with alarms and controls supplied by many
manufacturers, see Fact Sheet (S.T.E.P.)
CONTACTS
Craig Cogger, University of N.C., Raleigh,
NC
Bobby Carlile, Raleigh, NC
Dennis Osborne, University of N.C., Raleigh,
NC
Larry Robinson, Williamson County Health
Department, Franklin, TN
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-17
Soil Absorption
Shallow Trench(es)
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
LIMITING FEATURES
ROCK
GROUNWftTER
Source: Pennsylvania DER, 1983 (with modifications),
COMPONENTS
Pretreatment unit, e.g. septic tank, distri-
bution network, piping, gravel, and fill
material supplied locally
CONTACTS
Pretreatment
Wastewater Distribution Network
Gravity - drop box(s)
distribution box
Pressure - pump or siphon
Laterals \\ to 4 inch diameter, perforated pipe is located in 6 inches
of crushed ston'- or gravel
Loamy backfill capable of supporting vegetative growth (grass)
EXAMPLES
Hillside trench installations on sloping sites for small individual
or cluster type absorption areas.
County and State Health Department Officials
Installers/Contractors
(See Appendix II-B for a list of state contacts-)
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-18
Soil Absorption
Alternating Trench System
With Diversion Valve
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Source: U.S. EPA, 1980a.
COMPONENTS
EXAMPLES OF USAGE
Diversion valve
Watertight riser and access cap
Absorption areas - 50 to 100% of required land area
Residential installations, allows resting of 50 - 100% of required
absorption area.
Hull Run Valve, Mannassas, VA
Some diversion devices are made from com-
mercially available materials and fabricated
at the job site.
CONTACTS
Used extensively in eastern Tennessee by
local Health Department Officials
y
~N
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-19
Septic Tank-Sand Filtration-Irrigation
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
PUMPMG TAMt
Septic tank, sand filtration unit, pumping
tank, controls and supply distribution
system supplied locally
Disinfection -
Sprinklers - Toro Company (Minneapolis, MN)
Safe-T-Lawn, Inc., (Hialeah, FL)
Turf Sprinklers - Toro Company (Minneapolis, MN)
Rain Bird (Glendora, CA)
Bardie Irrigation (Laguna
Niguel, CA)
Disinfection - See separate Fact Sheet.
COMPONENTS
CONTACTS
Two-Compartment septic tank
Distribution - dosing pump or siphon
Sand filter with granular material
Under drains
Small diameter distribution network in gravel aggregate
Disinfection/pumping tank - store 1% days of wastewater
Submersible sewage effluent pump with controls and high water alarm
Supply distribution network with non-clogging (pop up) sprinkler
fixed sprinklers; Disinfection - stock feed chlorinator
EXAMPLES OF USAGE
Treatment and disposal of residential and other small flow sand filter
effluents by curf irrigation is increasing. This method is being used
in regions with stream discharge limitations and concerns about ground-
water recharge along the East Coast.
N.C. State AG Extension Services, Robert
Rubin
Turf Irrigation Equipment Companies
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-20
Evapotransplration Bed
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
1
r
Source: U.S. EPA, 1977a and 1980c.
COMPONENTS
Treatment units (septic tank, aerobic),
sand filter material, supply distribution
components, plastic liner supplied locally.
Vegetation stock or seed obtained from
local nursery.
CONTACTS
Sand Bed
Stone/Gravel Aggregate
Impermeable Plastic Liner
Distribution Piping
Vegetation with high (water) consumptive use (e.g., grasses, shrubs,
hardwood trees, and conifers)
EXAMPLES OF USAGE
Treating and disposal of small volume waste flows in the Appalachian Moun-
tain region. Process by itself not capable of treating large waste
flows due to high rainfall.
Madison County, NC Health Department, Mike
Bradley
Tims Ford Lake, TN TVA, Mr. Winford H. Long
Sequoyah Nuclear Plant
Richard Weigand, Wood County, Health Depart-
ment, Parkersburg, WV
Peter Kenning, Bowling Green State University,
Huron, OH
Knox County, TN Health Department, Mr. David
McKinney
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
/
FACT SHEET
ENGINEERING
TECHNIQUES
\
Figure 3-22
Small- Diameter
Gravity Sewers
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
COMPONENTS
Pretreatment - septic tank to prevent grease, grit, and other solids from
entering the collector mains
Collector Mains, 4*' to 8" diameter Plastic or larger
Cleanouts, 300' to 500' spacing and at special junctions
Manholes, maj o r j unctions, deep in tersections
EXAMPLES OF USAGE
Small diameter gravity sewers are being used to collect and transport
septic tank effluent from homes in sparsely developed areas with signi-
ficant savings in construction costs.
Septic tanks, cleanouts, manholes, and small
diameter plastic pipes can be supplied locally.
CONTACTS
Fountain Run, KY
Sadieville, KY
Lafayette, IN
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
(
FACT SHEET A
ENGINEERING
TECHNIQUES
Figure 3-23
Septic lank Effluent Pump
Pressure System
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
DOUBLE SEPTIC TANK
PUMPING TANK
Septic Tanks and pumping tanks are supplied
locally. Effluent pumps can be obtained
from local plumbing/building suppliers.
Pumps can be chosen from more than a dozen
manufacturers.
COMPONENTS
Two-compartment Septic Tank
Pumping tank with reserve capacity (l% days detention time)
Submersible sewage effluent pump
Level controls - floating mercury or mechanical
High water alarm with audible and visual signals
EXAMPLES OF USAGE
Septic tank effluent pumps can be utilized to convey partially treated
wastewater directly from septic tanks or separate pumping chambers via
small diameter lines W and larger to pressurized or gravity sewers,
to a soil absorption system or other final treatment and disposal facility.
CONTACTS
Fountain Run, KY
Inez, KY
Shadyville, KY
Berry, KY
Shallotte, NC
Cresswell, NC
Canterfield Development - Chapel Hill, NC
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
*^p^ifeS?;'--f ^ .\^ -'"' T"'*
' -f"-&.rf,.£t-' ->*V '-*£', ' ; , ^^ - - ii -'._«~ \ _" -^ic'wiW^PHSKif
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-24
Grinder Pumps
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
LEVEL SENSOR-
Source: U.S. EPA, 1977.
COMPONENTS
Tanks typically made by pump manufacturer
and sold as a package along with high level
alarms and controls.
ABS Pumps Inc. (Meriden, CT)
Environment/One Corp. (Schenectady, NY)
Goulds Pumps Inc. (Seneca Falls, NY)
Peabody Barnes Inc. (Mansfield, OH)
Gorman - Rupp Co. (Mansfield, OH)
CONTACTS
Storage tank - design flow plus reserve capacity, cone-fiberglass
Grinder pump with level controls; floating or small diameter discharge
line with check valve
EXAMPLES OF USAGE
Grinder pumps can be used to serve fron one to four residential dwellings
and lift wastewater to rather high elevation with simplistic means.
Small diameter service lines typically discharge to two to twelve inch.
Pressure of gravity mains leading to the final treatment facility.
Chickasaw Point Development, Lake Hartwell,
SC
Sacramento, KY
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-25
Lagoon
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
i-GREASE LAYER
t,
\
\
n
TT
8' TO 20' DEEP fj
e' THICK SLUDGE BLANKET j\
*-LINEH (IF NECE
Source: U.S. EPA, 1980c.
Pretreatment Units
Septic tank - see separate Fact Sheet
Aeration - see separate Fact Sheet
Sand filtration - see separate Fact Sheet
Package Plant - see separate Fact Sheet
Pond excavation, liner materials and piping
supplied locally.
COMPONENTS
CONTACTS
Types of Lagoons: Depth (ft)
High-rate aerobic 1 to 1.5
Facultative 3 to 8
Anaerobic Variable
Maturation 3 to 8
Aerated Variable
Pretreatment Unit
Excavated or built up area for wastewater storage, lined with clay,
asphaltic coating, bentonite, plastic or rubber membrane, or other
materials.
EXAMPLES OF USAGE
Lagoons have been providing low cost treatment of sewage from large and
small communities. Treatment performance has been increased by construct-
ing lagoons in series to lengthen detention times. Lagoons have been
used extensively in the southeast region of the U.S.
Individual State 201 Construction Grants
Program Offices
J
"N
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-26
Marsh-Pond-Meadow
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
\. Source: Pennsylvania DER, 1983.
COMPONENTS
Components for distribution system, marsh,
pond, and meadow locally supplied.
Coircninutors - See fact sheet for preliminary
treatment
Mechanical Aerators(mid-Atlantic and South-
eastern U.S.)
Barebo, Inc./Otterbine (Emmaus, PA)
Clow Corp., Waste Treatment Div. (Florence, KY)
Environmental Protection Specialists, Inc.
(Atlanta, GA)
FMC Corp., Material Handling System Div.
(Colmar, PA)
Infilco Degremont, Inc. (Richmond, VA)
Parkson Corp. (Ft. Lauderdale, FL)
Passavant Corp. (Birmingham, AL)
Schramm, Inc. (West Chester, PA)
Sydnor Hydrodynamics, Inc. (Richmond, VA)
Washington Aluminum Co. (Baltimore, MD)
Disinfection - See fact sheet for disinfection
CONTACTS
Comminutor
Aeration cell with aerator
Marsh with hydric vegetation (e.g., cattails, bullrush)
Fond - aerobic
Meadow - water-tolerant vegetation
Disinfection
Distribution piping
EXAMPLES OF USAGE
Treatment and disposal of flows typically less than 50,000 GPD. Iselin,
PA residential rural development; Neshaminy Falls, PA, mobile home park
Foster D. Diodato, PA Department of Eovi-
mental Resources, Harrisburg, PA 17101
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MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
^
FACT SHEET A
ENGINEERING
TECHNIQUES
Figure 3-27
Irrigation
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
EVAPORATION
GRASS AM)
NON-HARVESTED
VEGETATION
Source: U.S. EPA, 1979.
COMPONENTS
Cornell Industries (Williarastown, NY)
Long Mfg. N.C. Co. (Tarboro, NC)
McDowell Manufacturing Co. (Duliois, PA)
Toro Company (Minneapolis, MN)
James Hardie Irrigation (Laguna Niguel, CA)
Rain Bird (Glendora, CA)
Rainbow Mfg. Company (Fitzgerald, GA)
Valmont Industries, Inc. (Valley, NE)
CONTACTS
Pre-Treatment Unit
Primary - acceptable for isolated locations
Biological, e.g. lagoons - acceptable for controlled agricultural
irrigation
Disinfection
Storage tank or pond
Suitable area with buffer zone
Distribution system, sprinkler or surface piping, pump
EXAMPLES OF USAGE
Septic tank - sand filtration - irrigation, cropland, woodland
Aerobic treatment - zrrigation, cropland, woodland
Rubin, A. R., N.C. State University, Raleigh
Overcash, M., N.C. State University, Raleigh
Florence Alabama, Paul M. Giordana TVA
Unicoi, GA
Chickasaw Point Development, Lake Hartwell,
SC
White House, TN
Charlotte, TN
Gibson, TN
Helen, GA
Crofton, KY
Easley, SC
Cumberland Mountain State Park, TN
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
(
FACT SHEET A
ENGINEERING
TECHNIQUES
Figure 3-28
Conventional Gravity Sewers
(with or without lift station(s))
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Plastic Pipe
Crestline Plastic Pipe
Co.
Vassallo, Inc.
Century Fiberglass Co.
North Star Co.
Charlotte Pipe and
Foundary Co.
Certalnteed Corp.
Cast Iron Pipe
American Cast Iron Co.
Atlantic States Cast
Iron Pipe Co.
Griffin Pipe Prod. Co.
McWane Cast Iron Pipe
Co.
U.S. Pipe and Foundry
Co.
Asbestos Cement Pipe
Capco Pipe Co., Inc.
Certainteed Corp.
Concrete Pipe
United Concrete Pipe
GI1A Lock Joint
Price Bros. Company
U.S. Pipe and Foundry
Co.
Building Prod. Co.
Dickey Company
Kaul Clay Company
Larsen Clay Pipe Co.
Logan Clay Pipe Co.
COMPONENTS
CONTACTS
Minimum size: 6-inch diameter for all laterals in collection system
Minimum Slope: dependent upon size and wastewater flow characteristics
Concrete manholes every 300 to 500 ft or at changes in slope or direction
Pipe materials: asbestos-cement, clay, concrete, cast iron, and plastic
EXAMPLES OF USAGE
Gravity sewers are Che oldest and most common wastewater collection system
in existence. In rural areas, gravity sewers usually have the highest
capital costs of any type of wastewater collection system due to sparse
populations, the need for lift stations and potentially deep rack
excavations.
Local contractors, engineers, and pipe manu-
facturers.
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MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-29
Vacuum Sewers
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
re-
e: U.S. EPA, 1977a.
COMPONENTS
Collection/vacuum tank with pump
Vacuum/atmospheric pressure interface valve
Vacuum sewer lines
EXAMPLES OF USAGE
Vacuum sewers have been successfully used in areas that have flat to
gently sloping terrain with shallow and somewhat poorly drained soils.
Where terrain features favor gravity systems, vacuum sewers are seldom
a cost-effective method of wastewater collection.
Airvac, Inc. (Rochester, IN)
Envirovac, Inc. (Rockford, IL)
CONTACTS
Westmoreland, IN
Eastpoint, FL
Maryland Marine Utilities, Ocean Pines, MD
Queen Anne's County, MD (Kent Norrows/
Stevensville/Grosonville Area)
Centertown, KY
Broadcreek P.S.D. and Forest Beach P.S.D,
Hilton Head, SC
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MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
?$&A'>&e& : ' '.'- .,\s -V-£-'S'HH
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-30
Preliminary Wastewater Treatment
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Preliminary Treatment
Untreated
Was tewa te r
Bar Screen
or
Trash Rack
Comrninutor
(optional)
Flow
Meter
Grit
Chamber
Large
Solids
Inorganic
Solids
Purpose - To remove or shred large objects and grit which could damage
subsequent treatment units and pumps.
Notes - Wedge-wire screens could also be utilized to remove large
organic solids.
COMPONENTS
Screens
Grinder
Comminutor (usually part of influent piping for small systems)
Flow meter
EXAMPLES OF USAGE
J
\
Preliminary treatment is utilized at nearly all municipal wastewater treat-
ment plants and at many wastewater pumping stations.
Screens and grit removal
FMC Corp. (Colmar, PA)
Dorr-Oliver, Inc. (Stamford, CT)
Envirex, Inc. (Waukesha, WI)
Comminution (small systems)
Dorr-Oliver
Euramca Ecosystems, Inc. (Addison, IL)
Franklin Miller, Inc. (West Orange, NJ)
Dresser Industries, Jeffrey Mfg. Div.
(Woodruff, SC)
Various types of grit chambers have been manu-
factured; most types are for large municipal
treatment plants.
CONTACTS
Any sanitary engineer in the government or
private sector.
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MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-31
Rotating Biological Contactor (RBC)
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Submerged Inlet
to Rolorzone
Primary Sett lenient Tank
High Side
Source: Kentucky Cabinet for Human Resources, 19T-2.
COMPONENTS
inlet Ptpe
Final Settlement Tank
Chlorine Chamber
Outlet Pipe
Sludge Storage
Purestream Waste Treatment Division of Trans-
america Delavel, Covington, KY
CMS Rotardisk, Inc., Mississauga, Ontario
CONTACTS
Tank, steel or concrete
Circular Biological Contactors
Drive motor for circular disks
EXAMPLES OF USAGE
Treats flows from 400 to 100,000 GPD. 90-95% reduction in suspended
solids and BOD. Lowest operating costs among mechanical aerobic units.
Capable of treating residential, cluster, and small community waste
flows.
Lake City, SC
Hardinsburg, KY
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MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET N\
ENGINEERING
TECHNIQUES
Figure 3-32
Trickling Filter
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
trickling filter with fixed nozzles and automatic dosing tank
Purpose - To provide secondary
wastewater treatment prior to
disposal.
trickling liter with roan distributor
Note - Various types of filter media and various wastewater application
rates can be utilized. Preliminary treatment and settling are
preferred prior to filter use. J
COMPONENTS
Synthetic filter media
The Hunters Corp. (Ft. Myers, FL)
General Filter Co. (Ames, IA)
American Surfpac Corp. (West Chester, PA)
B.F. Goodrich Co., Enviro. Products (Akron, OH)
CONTACTS
Piping, including underdrains
Roctor synthetic media within enclosed structure, sometimes including a
cover
Dosing tank and siphon
Wastewater distributors: nozzels or disc distributors for small filters
Forced ventilation (optional)
EXAMPLES OF USAGE
Trickling filters are commonly utilized at both small and large wastewater
treatment facilities for municipal and industrial wastewaters.
Any sanitary engineer in the government or
private sector.
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-33
Contact Stabilization
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Screened
Degritted
Wastewater
IClarifierh
Effluent
Return
Sludge
Excess
Sludge
Note: The process requires smaller tank volume and shock loads are handled
better than in the conventional activated sludge technique. Flow
equalization is recommended particularly for plants smaller than
50,000 gallons per day if effluent is to be discharged to a surface
water body. Close operator attention is required.
Air Piffusers
Chemineer - Kenics, Inc. (Dayton, OH)
Compressors for Aerating Wastewater
BVS, Inc. (Honey Brook, PA)
Becker Pumps Corp. (Akron, OH)
Cooper Energy Services (Mt. Vernon, OH)
FMC Corp. (Colmar, PA)
Fuller Company (Bethlehem, PA)
Ingersoll-Rand (Mocksville, NC)
Joy Mfg. Co. (Montgomeryville, PA)
Schramm, Inc. (West Chester, PA)
Sulzer Bros., Inc. (New York, NY)
Numerous manufacturers of tanks, clarifiers,
and pumps are available.
COMPONENTS
CONTACTS
Contact tank with 30 to 60 minute wastewater detention time
Clarifier
Stabilization tank with sludge detention time of 2 to 6 hours
Air diffusers and compressors
The tanks and clarifier of tan can be purchased as one package plant unit.
EXAMPLES OF USAGE
This technique is commonly utilized as package wastewater treatment plants
throughout the country. An engineer at the state environmental protection
agency can provide specific examples within each state.
Water and Wastewater Equipment Manufacturers
Association, Inc. (P.O. Box 17402, Dulles
International Airport, Washington, DC 20041
(phone - 703-661-8011)) or your state envi-
ronmental protection agency.
(See Appendix II-B for a list of state agency
contacts.)
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MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-34
Extended Aeration/Activated
Sludge Wastewater Treatment
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Screened and
degritted
wastewater
with or with-
out primary
clarification
Return Sludge
Effluent .
to"
Disposal
Excess Sludge to
Sludge Treatment
Purpose - to oxidize organic matter and then to separate the oxidized
material away from the wastewater to the sludge. With addi-
tional detention time in the aeration tank(s)j ammonia-nitro-
gen can be oxidized to nitrate-nitrogen further reducing
the oxygen demanded by the wastewater.
Extended aeration units can be provided as \
part of a package plant. See figure 3-2 for
manufacturers of aeration tanks.
Clarifiers
Clow Corp., Waste Treatment Div. (Florence, KY)
Davco Div., Davis Water and Waste Industries,
Inc. (Thomasville, GA)
Dresser Industries, Inc., Jeffrey Mfg. Div.
(Woodruff, SC)
Enviro. Elements Corp. (Baltimore, MD)
FMC Corp., Material Handling Sys. Div. (Colmar,
PA)
Hendrick Fluid Systems Div. (Owensboro, KY)
Infilco Degrement, Inc. (Richmond, VA)
Kennecott Corp. (Knoxville, IN)
The F.B. Leopold Co. (Zelienople, PA)
Met-Pro Corp. (Harleysville, PA)
N.R.G. Co. (Ardmore, PA)
Parkson Corp. (Ft. Lauderdale, FL)
Passavant Corp. (Birmingham, AL)
Purestream, Inc. (Florence, KY)
Schreiber Corp. Inc. (Trussville, AL)
COMPONENTS
Aeration tank(s) with diffuser(s) and compressor or with agitator(s)
(see Figure 3-2), clarifier(s), valves and flow meter(s) in addition D
pipeline and pumps (as needed). Various types of aerators are availab
Inserts to clarifiers can be utilized
Various types of aei.ai.ui.:> *ii.e ava
to increase solids settling.
:o
ible.
EXAMPLES OF USAGE
These processes are commonly utilized at municipal and package treatment
plants to provide secondary wastewater treatment. The wastewater may or
may not have undergone primary treatment (clarification) prior to reaching
the aeration tank.
CONTACTS
See various references for design criteria
(e.g., Fair et al., 1968, and WPCF, 1977).
Contact any sanitary engineer.
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MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-35
Advanced Wastewater Treatment
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Multi-media filters - Suspended solids and any substances absorbed onto
those solids are removed from solution.
Nitrification - ammonia is oxidized to nitrate in order to reduce the
oxygen demanded by the wastewater.
Nitrogen removal - Nitrogen can be biologically converted (under anaerobic
conditions) to nitrogen gas, stripped at high pH as ammonia gas or removed
from solution by ion exchange.
Phosphorus removal - lime or alum can be added prior to final clarifica-
tion to allow phosphorus to precipitate from solution as a metal-phosphate.
Activated carbon - powdered or granular carbon provides opportunity for
adsorption of organics onto the carbon surface.
Purpose - to remove substances from wastewater that are not sufficiently
removed in preceding treatment processes.
More intensive operation of the process is needed than for other preceding
treatment processes.
Filters
Clow Corp., Waste Treatment Div. (Florence, KY)
Davco Div., Davis Water and Waste Ind., Inc.
(Thomasville, GA)
Nutrient Removal (patented processors)
Dorr-Oliver (Stamford, CT)
Schramm, Inc. (West Chester, PA)
Air Products and Chemicals, Inc. (Allentown, PA)
Activated Carbon
Calgon Corp. (Pittsburgh, PA)
Westvaco Corp. (Covington, VA)
1CI Americas, Inc. (Wilmington, DE)
COMPONENTS
CONTACTS
Advanced treatment processes can be used separately or in combination.
Chemicals may be needed as well as tanks, aerators, clarifiers, piping,
meters, pumps and special equipment for certain processes (e.g., strip-
ping tower for ammonia stripping).
EXAMPLES OF USAGE
Treatment facilities in the Great Lakes region include phosphorus removal.
Nitrogen removal is included at some treatment facilities which discharge
to coastal waters and other environmentally-sensitive surface waters.
Sanitary engineers and regulatory officials
experienced with advanced wastewater treat-
ment processes.
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-36
Sludge Treatment
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Sludge Stabilization - Processes which chemically or biologically reduce
microbial activity and odor production often while improving the ability
of sludge to be dewatered. Examples of sludge stabilization processes for
small facilities are lagoons, aerobic digestors, and use of lime or
chlorine.
Sludge Drying - Processes which reduce the water content and volume of
sludge to be disposed. Drying can occur due to solid-liquid separation,
liquid evaporation and liquid filtration. Examples of sludge drying
processes for small facilities are lagoons and drying beds (with or with-
out covers).
More sophisticated processes which require more operation and maintenance
are in wide use at many larger, municipal wastewater treatment plants.
Aerobic digestion equipment
Dean Products, Inc. (Brooklyn, NY)
Walker Process Corp. (Aurora, 1L)
Welles Products Corp. (Roscoe, IL)
COMPONENTS
CONTACTS
Various types of unit structures and pumps are utilized depending upon
the process(es) to be utilized, llixers and/or aeration equipment could
also be utilized.
Head can be added to enhance stabilization or drying. Chemicals or
forced air could be added to enhance drying.
EXAMPLES OF USAGE
Any municipal wastewater treatment plant.
Any sanitary engineer in the government or
private sector.
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-37
Septage or Sludge Disposal
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Injector attat hment mounted behind wheel ailo* s slurry placement between crop rows.
Courtesy of: Term State Ag. Extension Service
Large (volume)
AG Chem
Big A
Small (volume)
Martin
Calumet
Avco
Deere & Co.
Sperry-New Holland
COMPONENTS
Land application/agricultural utilization
Surface, topdressing of grasses
Subsurface, injection on grassland and row crops
Trench disposal
Landfilling
Cotreatment at coventional wastewater treatment plant
EXAMPLES OF USAGE
Liquid manure spreaders with subsurface injectors are capable of dis-
posing sludge from septic tanks and aerobic treatment units, onto agricul-
tural lands. Septage has been successfully spread on grasses and plant
residues. Surface spreading normally requires incorporation by discing
for odor control. Sludge can also be composted and used on agricultural
lands.
CONTACTS
Municipal wastewater Treatment Plant Operations
Local septage haulers
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-39
Waste Flow Reduction
Water Conservation
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
Water Conservation
Water-Saving Devices and Fixtures
- Water carriage toilet inserts
- Doms
- Bottles
- Bathing devices
- Reduced flow showerheads and inserts
- On/Off showerhead valves
- Water Saving Toilets
- Non-water carriage toilets
- Composting
- Incineration
- Water meters
COMPONENTS
Aerators
Flow restrictors and line inserts
Toilet tank retrofit units (dual flush valves, dams, repair kits)
Repair kits for leaky fixtures
Water saving appliances
Level adjusters
Water Meters
J
"N
Nearly 70 principal manufacturers of fix-
tures and other water saving devices through-
out the U.S.
CONTACTS
EXAMPLES
GE
Implementing water conservation procedures and installing waterflow
reduction devices can result in significant reduction in water useage.
Reduction in hydraulic loadings to soil absorption systems has enhanced
system performance, corrected malfunctions and extended the periods of
use.
J
"\
Local plumbing dealers
-------
MOUNTAIN COMMUNITIES
WASTEWATER MANAGEMENT
ASSESSMENT
ALTERNATIVES
DEVELOPMENT REPORT
FACT SHEET
ENGINEERING
TECHNIQUES
Figure 3-40
Waste Flow Reduction
Wastewater Recycle/Reuse
-------
DESCRIPTION OF SYSTEMS
MANUFACTURER
( Other \_
V Wastewater J~
Treatment and Disposal
(e.g. Septic Tank/Soil
Absorption
Excess
Components making up the system available
from local plumbing supply and hardware
stores.
COMPONENTS
CONTACTS
Separate water supply and drain liners
Filters
Chemicals
Storage tanks
Separate disposal system for resultant toilet waste and all gray water
wastes
EXAMPLES OF USAGE
Wastewater recycle and reuse systems generally collect and treat gray-
water for future use in water-carriage toilets and possibly turf irriga-
tion. Only sanitary and excess graywater enters the septic tank - soil
absorption system.
Center for Improving Mountain Living, West-
ern Carolina University, Cullowhee, NC
-------
CHAPTER 3 BIBLIOGRAPHY
-------
BIBLIOGRAPHY
CHAPTER 3
American Society of Agricultural Engineers (ASAE). 1978. Home Sewage
Treatment. Proceedings of the Second National Home Sewage Treatment
Symposium held December 12-13, 1977. Published by ASAF. St. Joseph,
MI. ASAE Publication 5-77.
American Society of Agricultural Engineers (ASAE). 1982. On-Site
Sewage Treatment. Proceeding of the Third National Symposium on
Individual and Small Community Sewage Treatment held December 14-
15, 1-82. Published by ASAE. St. Joseph, MI. ASAE Publication
1-82
Berkowitz, S.J. 1981. On-Site Wastewater Treatment Problems and Alternatives
for Western North Carolina. Center for Improving Mountain Living.
Western Carolina University. Cullowhee, NC. Published by the
Water Resources Research Institute of the University of North
Carolina, Raleigh, NC. Report No. 163.
Boyle, W.C. and R.J. Otis. 1979. On-Site Treatment. University of
Wisconsin. Madison, WI.
Pair, G.M., J.C. Geyer and D.A. Okun. 1968. Water and Wastewater
Engineering. Volume 2. Water Purification and Wastewater Treatment
and Disposal. John Wiley & Sons, Inc.
Hyland, P. On-Site Disposal in Rural Kentucky. Legislative Research
Commission Research Report No. 155. Frankfort, KY.
Kentucky Cabinet for Human Resources. 1982. Kentucky On-Site Sewage
Treatment Systems. Technical Manual. Department for Health
Services. Frankfort, KY.
Laak, R. 1980. Wastewater Engineering Design for Unsewered Areas. Ann
Arbor Science Publishers, Inc. Ann Arbor, MI.
Mancl, K.M. 1983. Septic Tank Pumping. The Pennsylvania State University.
College of Agriculture, Cooperative Extension Service. State College,
PA. Publication SW-40.
McClelland, N.E. 1976 through 1980. Proceedings, Individual On-Site
Wastewater Systems. National Sanitation Foundation, Ann Arbor
Science. Ann Arbor, MI.
Municipal Index (Published annually). Morgan-Grampian Publishing Co.
Pittsfield, MA.
Nicholas, G.D. and Foree, E.G. 1981. Evaluation of Boyd County, Kentucky
Sanitation District No. 3 Home Wastewater Treatment Systems.
Applachian Regional Commission and Kentucky Department for Community
and Regional Development. Published by Commonwealth Technology
Inc.' Lexington, KY.
-------
Otis, R.J., Boyle, W.C. et al. 1977. On-Site Disposal of Small Wastewater
Flows. University of Wisconsin. Madison, WI.
Pennsylvania Department of Environmental Resources (DER). 1983 (plus
up-dates). Technical Manual for Sewage Enforcement Officers.
Prepared by the Local Government Research Corp. State College, PA.
Public Works Journal Corporation. 1984 Public Works Manual. Ridgewood,
NJ.
Salvato, J.A. 1982. Environmental Engineering and Sanitation. Third
Edition. A Wiley-Interscience Publication. John Wiley and Sons,
Inc.
Schutz, F.R. 1983. Madison County Clean Waters Project, Step I Sewage
Facilities Planning Report. F.R. Schutz Consulting Engineers.
Asheville, NC.
Triangle J Council of Governments. 1980. Final Report Individual
Wastewater Project. 1978-79. Triangle J Council of Governments.
Research Triangle Park, NC.
U.S. Environmental Protection Agency (EPA). 1977. Alternatives for
Small Wastewater Treatment Systems. 1. On-Site Disposal/Septage
Treatment and Disposal and 2. Pressure Sewers/Vacuum Sewers. EPA
Technology Transfer Seminar Publication (EPA-625/4-77-011).
U.S. Environmental Protection Agency. 1977. Process Design Manual;
Wastewater Treatment Facilities for Sewered Small Communities.
Environmental Research Information Center. Cincinnati, OH.
(EPA-625/1-77-009).
U.S. Environmental Protection Agency. 1979. Design Seminar Handout;
Small Wastewater Treatment Facilities. EPA Technology Transfer.
Environmental Research Information Center. Cincinnati, OH.
U.S. Environmental Protection Agency. 1980a. Design Manual; On-Site
Wastewater Treatment and Disposal Systems. Office of Water Program
Operations (Washington, DC) and Office of Research and Development.
Municipal Environmental Research Laboratory. Cincinnati, OH.
EPA 625/1-80-012.
U.S. Environmental Protection Agency. 1980b. Evaluation of Sludge
Management Systems; Evaluation Checklist and Supporting Commentary.
Office of Water Program Operations. Washington, D.C. Publication
MCD-61 (EPA 430/9-80-001).
U.S. Environmental Protection Agency. 1980c. Innovative and Alternative
Technology Assessment Manual. Office of Water Program Operations
and Office of Research and Development. Washington, D.C.
Publication MCD-53 (EPA 430/9-78-009).
-------
U.S. Environmental Protection Agency. 1980d. Planning Wastewater
Management Facilities for Small Communities. Municipal Environmental
Research Laboratory. Cincinnati, OH. (EPA-600/8-80-030).
U.S. Environmental Protection Agency. 1981. Generic Facilities Plan
for a Small Community; Stabilization Pond and Oxidation Ditch.
Office of Water Program Operations. Washington, D.C. Publication
FRD-18 (EPA-430/9-81-007).
U.S. Environmental Protection Agency. 1982a. Construction Grants '82.
Office of Water Program Operations. Washington, D.C.
U.S. Environmental Protection Agency. 1982b. Draft Environmental Impact
Statement; Blount County, Tennessee Wastewater Facilities.
EPA 904/9-82-103. EPA-Region IV, Atlanta, GA.
U.S. Environmental Protection Agency. 1983. Rural Lakes Project Handbook,
Region V. Water Division. Chicago, IL.
Water Pollution Control Federation and American Society of Civil Engineers.
1977. Wastewater Treatment Plant Design; A Manual of Practices.
Prepared by a joint committee.
-------
VOLUME II APPENDICES
-------
APPENDIX II-A SITE SOIL SURVEY PROCEDURES
-------
APPENDIX II-A
SITE SOIL SURVEY PROCEDURES1
Observation and evaluation of soil characteristics can best be determined
from a pit dug by a backhoe or other excavating equipment. However, an
experienced soil tester can do a satisfactory job by using a hand auger or
probe. Both methods are suggested. Hand tools can be used to determine soil
variability over the area and pits used to describe the various soil types
found.
Soil pits should be prepared at the perimeter of the expected soil
absorption area. Pits prepared within the absorption area often settle after
the system has been installed and may disrupt the distribution network. If
hand augers are usedj the holes may be made within the absorption area.
Sufficient borings or pits should be made to adequately describe the soils in
the area, and should be deep enough to assure that a sufficient depth of
unsaturated soil exists below the proposed bottom elevation of the absorption
area. Variable soil conditions may require many pits.
Since in some cases subtle differences in color need to be recognized, it
is often advantageous to prepare the soil pit so the sun will be shining on the
face during the observation period. Natural light will give true color
interpretations. Artificial lighting should not be used.
1. Soil Drainage
Soil drainage refers to the freedom from saturation of the soil pores. It
relates directly to the balance of air and water in the internal pores of
the soil. You can obtain direct evidence of drainage conditons in some
cases by observing free water on the surface of the soil, in shallow wells
or test probes, or by the presence of springs or seepy spots. The water
table can be best observed in test pits dug in early spring and allowed to
stay open and fill with water as the water table approaches equilibrium.
-------
You can infer the soil drainage conditions to an extent by type of
vegetation and plant root penetration. Soil drainage characteristics can
also be inferred by soil colors. Bright, uniform brown, red, and yellow
colors are associated with good drainage. Grey, pale yellow, blue, and
green colors are associated with poor drainage and lack of aeration. Soil
mottling is a variegated color pattern in the soil and is associated with
a fluctuating water table. Black or very dark grey surface soil is
associated with saturation for long periods of time. Metallic black
coatings are usually concentrations of manganese formed as a result of
restricted drainage.
The following drainage classes are of importance to the Sewage En-
forcement Officer:
a. Well Drained - free of mottling to 40 inches; usually suitable for
elevated sand mounds or in-ground systems if sufficient soil depth
exists.
b. Moderately-well Drained - Mottled in lower B and/or upper C Horizon
beginning at 20 inches to 40 inches; usually suitable for elevated
sand mounds.
c. Somewhat Poorly Drained - mottled in upper B Horizon or lower A
Horizon - beginning 10 inches to 20 inches from the surface;
unsuitable.
d. Poorly Drained - grey or light grey surface soil. Mottled or
gleyed soil begins less than 10 inches from the surface; unsuitable.
e. Very Poorly Drained - black or very dark grey surface soil mottling
or gleying begins at or very near the surface; unsuitable.
2. Soil Permeability
Soil permeability is the rate of air or water movement through the soil.
Factors that affect permeability are as follows:
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a. Texture
Texture is the "feel" of the soil. The coarseness or fineness of the combination of
mineral particles that together make up the soil. Most soils are made up of a
mixture of particles that fall in three general classes: sand, silt, and clay. Sand
is the coarsest material with a range in size from two millimeters to .05
millimeters. Silt is smaller yet, from .05 millimeters to .002 millimeters, often
called two microns. Clay particles are all smaller than .002 millimeters.
The soil may also contain coarse rock fragments of one-quarter inch or larger.
These fragments come in a range of sizes and shapes. For example, channery soils
have significant quantities of flat rock fragments up to an inch thick and two to
six inches in length and width. Flaggy fragments are somewhat larger than
channery. These are less permeable than the soil around them. Because coarse
fragments usually afford no renovation, it is important to know what proportions
of the soil they occupy. The measurement must be made by volume, not weight,
because they are heavier than the surrounding soil.
When considering waste disposal, a good blend of sand, silt, and clay is most
desirable. One hundred percent sand has no chemical renovating power.
One hundred percent silt has poor stability and little renovating capacity. Clay is
the most important class of soil particles for renovating waste. However,
excessively clayey soil has poor permeability. The presence of clay can be
determined by the plasticity of the soil when wet, as well as by texture. The clay
is sticky and helps bind the other soil particles together into aggregates.
b. Structure
The important factors in soil structure are the size, shape, and stability of the
aggregate soil particles called "peds." The simpliest ped is a loose cluster of soil
particles held together by clay and colloidal organic matter. This is called a
granule and is common in surface soils. These granules are rounded, do not pack
tightly and, therefore, are permeable.
In subsoils with a moderate to high proportion of clay, blocky structure is often
found. Such structure results largely from the alternate swelling and cracking
associated with alternate wetting and drying over long periods of time. These
blocks under certain conditions have angular edges and corners, and the soil is
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called blocky. They do not fit together tightly even when wet; therefore,
permeability is greater than angular blocky.
In the granular, blocky, and subangular blocky structures, the length, width, and
height of the peds are roughly the same. If the vertical dimension, thickness is
less than one-third as great as the horizontal dimension, length, the structure b
described as platy. Platy soils have restricted permeability. A fragipan very
often has platy structure and may be so low in permeability that it holds water on
top of it, causing a perched water table.
If the long dimension of the structural unit is the vertical dimension and it is
three times as great as the horizontal dimension, the structure is described as
prismatic. The permeability of prismatic soil is generally similar to that of
blocky soil.
Stability of soil structure is classed as weak, moderate, or strong. Weak structure
is poorly formed and readily crumbles. Strong structure is conspicuous and
durable, resisting crumbling. Moderate is an intermediate class.
The effect of detergents is to decrease the adherence between soil particles and,
hence, decrease permeability and stability of peds. This dispersion of the soil
particles can render a soil structureless.
, Depth
Depth is an important characteristic because there must be sufficient depth of soil to
allow the storage of the effluent while the chemical and biological actions are taking
place and to provide adequate filtration. Adequate soil must be available also to
provide sufficient depth for construction of the disposal system.
t, Consistence
Consistence is an easily-observed soil characteristic, but it is one that can change from
day to day. Each soil has three sets of consistence characteristics - one for when it is
wet, one for moist, and one for dry conditions. These can affect the actions of roots
and animals in the soil and may hamper or limit mechanical operations of installing a
sewage disposal system. It is also an important consideration of interpreting
permeability.
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5. Stoniness and Rockiness
Stoniness and rockiness indicate presence of stony or rocky conditions. Stoniness has
already been discussed as one category of coarse fragments. Stones are unattached to
bedrock. Rockiness is the presence of ledges or outcrops of bedrock reaching the
surface. These conditions may present serious obstacles to mechanical operations,
reduce extent of renovation, or facilitate movement of sewage effluent to ground water
through fractures in the rock.
6. Flooding
Flooding refers to the overflow of an area by a stream or river, or by runoff in a
drainage way or depression. Any overflow onto an installed subsurface disposal system
greatly increases the chances of failure of that system either through destruction of the
system by erosion or through interruption of the renovative process and clogging of the
system. Such conditions also increase the probability of pollution.
E. interpreting Soil Suitability for Subsurface Disposal of Septic Tank Effluent
1. Suitable - deep, well-drained, permeable soil with good filtration.
2. Suitable but with Hazard of Ground Water Pollution - deep, well-drained, permeable soil
over gravel or limestone with fissures.
3. Marginal - moderately-deep or moderately-sloping soils.
4. Unsuitable - steep, shallow, not well-drained or subject to flooding.
F. Limiting Zone
Any horizon or condition in the soil profile or underlying strata which will interfere in any
way with the renovation of sewage effluent before entering the ground water table is called
a limiting zone. Limiting zones can consist of the presence of a water table condition
sufficiently close to the surface that sewage effluent could be introduced to the ground
water before being renovated by passage through suitable soils. Soil mottling is the most
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common indicator of a water table condition because it is evidence that the soils have been
saturated sufficiently long enough to cause a chemical or physical change. Water tables can
be either seasonal, regional, or perched (natural surface drainage restricted or held back by
a soil structure).
The presence of a rock formation, other stratum, or even a soil condition which is so tight
and impermeable that it effectively limits the downward passage of effluent is considered a
form of limiting zone.
Rock with open joints, fractures or solution channels, or masses of loose rock fragments,
including gravel, are all conditions which permit the downward passage of sewage effluent
without proper renovation. The presence of these conditions indicates a lack of soil
material through which the sewage effluent may filter and be renovated. A limiting zone
exists whenever sewage effluent may pass freely through a portion of the soil horizon
without renovation.
G. Procedure for Examining a Soil Profile
A Sewage Enforcement Officer should gather as much information as is possible regarding a
site of a proposed on-lot system before evaluating a soil probe.
1. Before visiting the site, the Sewage Enforcement Officer may gather information
regarding soil suitability and site limitations from any or all of the following:
a. Local land owners, farmers, or municipal officials.
b. Well drillers.
c. County agents of U.S.D.A.
d. The local sanitarian.
e. The local Soil Conservation Service office.
f. U.S.G.S. maps of the area.
g. Soils survey for the county, if available.
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2. If any of the information obtained before visiting the site would indicate the possibility
of a floodplain, consult the local municipality's Federal Flood Insurance mapping, if
available, or the S.C.S, mapping for identification of floodplains or flood prone soils.
3. On the initial visit to the site, check for obvious, unsuitable characteristics such as
standing water, rock outcrops, slopes, or other conditions which would render the site
unsuitable. Estimate the total
amount of land available for use as an absorption area and make a rough determination
of the slope.
*. It is recommended that all interested parties be present at the time of the soil
evaluation, so that all can see the same conditions and obvious deficiencies can be
explained immediately. If at all possible, it is recommended that the Sewage
Enforcement Officer be present on the site as the soil probe is being excavated.
5. If road cuts, railroad embankments, or other exposed slopes are present, try to get a
broad view of the landscape, soil, and geology of the area surrounding the site. Select
potential sites for absorption areas on the lot and designate the probe locations. Check
and record the slope over the potential sites.
6. Have soil probes excavated if no obvious, unsuitable characteristics are observed and if
the slope is within the limits prescribed by the regulations.
Examine the soil as it is removed for the
presence of mottling, structure, bedrock, or other indicators of unsuitability. Before
entering the probe to perform the examination of the soil profile, make sure that the
probe is safe to enter. Check to be sure that the probe is constructed properly with a
step-type configuration to allow safe entry and exit. The probe should have no side-
wall slumps or show the potential for a cave-in. Be sure that no heavy piece of
equipment or large objects, such as rocks or boulders, is resting on the surface
immediately adjacent to the probe sidewalls. Once in the probe, check and make sure
that no type of soil or rock debris will topple into the probe. If present when the probe
is dug, have the operator align the excavation so that the best use can be made of the
available sunlight.
7. Check the sidewalls of the probe to determine which wall will be described. Chose the
soil face which will best represent the soil condition present. Using a pick-type tool
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such as a knife, sharp hammer, or screwdriver, probe the sidewall from the
top to bottom to reveal a fresh surface at least 10 inches wide. Make a
general description of the probe, including such things as slope of the
area, depth of the probe, depth to bedrock, depth to drainage mottling,
depth to pan, depth to ground water, depth to seeps, and depth of the root
zone. By repeated jabbing of the sidewall of the probe, the evaluator can
identify changes in soil density and, thereby, identify different
horizons. Heavy structures or pan-like limiting zones can be identified
by their resistance to penetration.
8. Using the prepared section of the probe, identify horizons; measure the
depth to the beginning and end of the horizons, and mark the lower
boundaries with nails or other identifying objects.
9. Work from the lowest horizons toward the top of the probe to avoid
disrupting the undescribed horizons as the lower soil is examined.
10. Describe the characteristics of each horizon using color, texture,
consistency, structure, presence of roots or animal life; coarse frag-
ments, bedrocks, mottling; examine the coarse fragments and bedrock and
identify the type if possible.
11. Avoid making verbal decisions regarding suitability of the probe for a
certain type of system. This should be reserved until the results of the
percolation test and other factors can all be analyzed together. If the
soil is unsuitable for the installation of an on-lot system, the permittee
or persons available should be advised and notified that a percolation
test may not be performed. The findings of a soils evaluation should be
recorded. As a part of the soils description, the evaluator should
designate the type of limiting zone present and the depth from the mineral
soil surface observed.
This description is mostly taken directly from the, Technical
Manual for Sewage Enforcement Offices, Pennsylvania Department
of Environmental Resources, 1983.
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APPENDIX II-B STATE HEALTH DEPARTMENT CONTACTS
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APPENDIX II-B
STATE HEALTH DEPARTMENT CONTACTS
Mr. Mike Cash
Director
Bureau of Sanitation
State Office Building
Room 316
Montgomery, AL 36130
(205)261-5007
Mr. Wilton Garrett
Environmental Protection Manager
Georgia Department of Human Resources
47 Trinity Avenue
Atlanta, GA 30334
(404)656-7045
Mr. Don Dixon
Section Supervisor
Food and Sanitation Branch
Department for Health Services
DBS Building
2nd Floor West
275 E. Main Street
Frankfort, KY 40621
(502)564-4856
Mr. Steve Steinbeck
Supervisor, On-Site Sewage Disposal Unit
P.O. Box 2091
Raleigh, NC 27602-2091
(919)733-2261
Mr. Phillip Cooper
Director, Division of General Sanitation
South Carolina Department of Health
and Environmental Control
2600 Bull Street
Columbia, SC 29201
(803)758-3908
Mr. L. Eugene Barnett
Division of Environmental Sanitation
Tennessee Department of Public Health
R.S. Gass State Office Building
Ben Allen Road
Nashville, TN 37216
(615)741-7206
*U.S. GOVERNMENT PRINTING OFFICE* 9 8"* -545-06 3/
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