r
URBAN BMP COST AND EFFECTIVENESS
SUMMARY DATA
FOR 6217(g) GUIDANCE
ONSITE SANITARY DISPOSAL SYSTEMS
January 29, 1993
WOODWARD-CLYDE
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URBAN BMP COST AND EFFECTIVENESS
SUMMARY DATA
FOR 6217(g) GUIDANCE
LIBRARY
US EPA Region 4
AFC/9th FL Tower
61 Forsyth St. S.W.
Atlanta, GA 30303-3104
ONSITE SANITARY DISPOSAL SYSTEMS
January 29, 1993
WOODWARD-CLYDE
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ACKNOWLEDGEMENTS
The authors of this report were Mr. Dale Lehman, Mr. Brian Donovan, and Mr. Dan Sheridan
of Woodward-Clyde.
The authors would like to thank Mr. Rod Frederick and Mr. Robert Goo of the Unites States
Environmental Protection Agency (EPA) for their guidance and comments during the
development of this document.
The project was funded by the EPA Assessment and Watershed Protection Division.
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TABLE OF CONTENTS
1.0 INTRODUCTION 1-1
2.0 ONSITE SANITARY DISPOSAL SYSTEMS MANAGEMENT
PRACTICES EFFECTIVENESS AND COST SUMMARY 2-1
2.1 DESCRIPTION OF ONSITE SANITARY SYSTEMS
MANAGEMENT PRACTICES 2-1
2.2 EFFECTIVENESS 2-10
2.3 COST 2-14
3.0 EFFECTIVENESS AND COST SUMMARY TABLE 3-1
4.0 MANAGEMENT PRACTICES OPTIONS 4-1
4.1 NEW OSDSs 4-1
4.2 REPLACEMENT OR ENHANCEMENT OF EXISTING OSDSs 4-5
5.0 REFERENCES 5-1
APPENDICES
A. STATE REGULATIONS
B. RESIDENTIAL SEPTAGE POLLUTANT LOADS
C. IMPLEMENTATION RESTRICTIONS
D. EFFICIENCY DATA
E. COST DATA
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LIST OF TABLES
TABLE 1-1. Water Use and Pollutant Loadings
by Category 1-3
TABLE 1-2. Reduction in Pollutant Loading by
Elimination of Gargage Disposals 1-3
TABLE 2-1. Minimum Lot Sizes Required to Accomodate
a Septic Tank Leaching Field 2-2
TABLE 2-2. Suggested Septic Tank Pumping
Frequency (Years) 2-10
TABLE 3-1. OSDS Effectiveness and Cost Summary 3-2
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1.0
INTRODUCTION
In November 1990, the U.S. Congress passed the Coastal Zone Act Reauthorization and
Amendments (CZARA). As part of this reauthorization, Congress created a new, distinct
program to address nonpoint source (NPS) pollution of coastal waters (Section 6217). The U.S.
Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric
Administration (NOAA) jointly drafted Proposed Program Guidance for Section 6217. EPA was
given the lead responsibility for developing the Management Measures Guidance required under
Section 6217(g) of CZARA.
EPA established five Federal/State Work Groups to assist in preparation of the 6217(g)
Guidance. Woodward-Clyde has supported the Urban Work Group through the collection and
analysis of information on Best Management Practices (BMPs) used to control urban NPS
pollution. The results of these efforts includes four books that present cost and effectiveness
information on BMPs for:
• Erosion and Sediment Control;
• Post Construction Runoff;
• Onsite Sewage Disposal Systems; and
• Roads, Highways and Bridges.
This report is a summary of the cost and pollutant removal effectiveness information that was
obtained from published literature regarding onsite sanitary disposal systems (OSDSs). The
report also contains options for management practices and systems of management practices for
control of nonpoint source (NPS) pollution from OSDSs. These options are based on the
information obtained from the literature review.
This document contains information from nearly 60 documents. The documents were obtained
through literature searches and telephone contacts with all states and territories with approved
Coastal Zone Management Plans. Cost and effectiveness data from the various management
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practices presented in the documents were reviewed and analyzed to summarize the information.
Data were omitted from consideration where substandard field technique was used in the
collection of the data or if results were influenced by atypical climatological or site
characteristics (e.g. high water table or heavy water loads to the system). Also, only
management practices that were applied in the field were considered. Experimental practices
only applied in a research setting were not considered.
Many of these documents indicate the need to address NPS pollution originating from OSDSs.
The Chesapeake Bay Program (1990) found that 55%-85% of nitrogen entering an OSDS can
pass into the groundwater. OSDSs account for 74% of the nitrogen entering Buttermilk Bay (at
the northern end of Buzzard's Bay) in Massachusetts (Horsely Witten Hegeman, 1991). Similar
results were obtained from studies performed on the Delaware Inland Bays (Reneau, 1977;
Ritter, 1986). These studies indicated that septic systems were major contributors of nitrogen
entering into the Delaware Inland Bays. Assawoman Bay, Indian River Bay, and Rehoboth Bay
received 15%, 16% and 11% of their nitrogen from septic systems, respectively. Groundwater
discharges of NPS pollution were estimated to contribute 75 % of the total nitrogen entering the
Bays (Reneau, 1977).
Water flow reduction can help to diminish NPS pollution by increasing the residence time within
OSDSs and reducing hydraulic load to the system. Flow saving devices such as water saving
appliances, flow reducing fixtures, and low flush toilets can be installed in new buildings, or
used to replace existing equipment as it wears out. When these devices are used in connection
with management practices for new and replacement construction, the reduced flows save costs
by reducing the size of new and retrofit treatment facilities, extending the life of OSDSs,
increasing performance of existing facilities, and lowering costs of operation for holding tanks.
Cost savings have also been documented due to reduced demands for potable water (Logsdon,
1990). The cost is minimal, especially for replacement when a fixture breaks.
Table 1-1 compares various sources of water usage with typical pollutant loadings.
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Table 1-1. Water Use and Pollutant Loadings by Category
Water Use
Volume
(1/capita)
BOD
(g/capita)
SS
(g/capita)
Total N
(g/capita)
Total P
(g/capita)
Garbage
Disposal
4.54
10.8
15.9
0.4
0.6
Toilet
61.3
17.2
27.6
8.6
1.2
Basins and
Sinks
84.8
22.0
13.6
1.4
2.2
Misc.
25.0
0
0
0
0
Totals
175.6
50.0
57.1
10.4
4.0
Source: EPA, 1980
Table 1-2 summarizes the effectiveness of eliminating garbage disposals in reducing the loadings
of pollutants in wastewater.
Table 1-2. Reduction in Pollutant Loading by Elimination of Garbage Disposals
Parameter
Reduction in Pollutant
Loading (%)
SS
25-40
BOD
20-28
Total N
3.6
Total P
1.7
This report contains descriptions of the management practices considered, summary cost and
effectiveness information, and recommended management practices options for use in OSDSs.
The appendices present the data analyzed to develop the summary cost and effectiveness
information.
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INDEX
MANAGEMENT
PRACTICE
PRACTICE
DESCRIPTION
PRACTICE
EFFECTIVENESS
PRACTICE
COST
Aerobic Treatment Units
Page 2-8
—
—
Alternate Trench
Page 2-3
Page 2-12
Page 2-14
Anaerobic Upflow Filter
Page 2-4
Page 2-12
Page 2-14
Center Sewage Treatment
Facility
Page 2-6
Page 2-13
Page 2-15
Cluster Systems
Page 2-7
Page 2-13
Page 2-15
Constructed Wetlands
Page 2-6
Page 2-13
Page 2-16
Conventional Septic
System
Page 2-1
Page 2-11
Page 2-14
Disinfection Devices
Page 2-8
Page 2-14
Page 2-16
Eliminating Garbage
Disposals
Page 2-7
Page 2-13
Page 2-15
Evapotranspiration
Systems
Page 2-7
Page 2-12
Page 2-15
Fixed Film Systems
Page 2-8
—
—
Intermittent Sand Filter
Page 2-3
Page 2-12
Page 2-14
Low Phosphate Detergents
Page 2-7
Page 2-12
Page 2-14
Low Pressure Systems
Page 2-3
Page 2-11
Page 2-14
Mound Systems
Page 2-2
Page 2-11
Page 2-14
Recirculating Sand Filter
Page 2-4
Page 2-12
Page 2-14
RUCK System
Page 2-6
Page 2-12
Page 2-15
Trenches and Beds
Page 2-5
Page 2-12
Page 2-14
Vaults and Holding Tanks
Page 2-7
Page 2-13
Page 2-16
Water Conservation
Fixtures
Page 2-8
Page 2-13
Page 2-16
Water Separation System
Page 2-6
Page 2-12
Page 2-15
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2.0
ONSITE SANITARY DISPOSAL SYSTEMS MANAGEMENT SYSTEMS
EFFECTIVENESS AND COST SUMMARY
This section describes the types of Onsite Sanitary Disposal System (OSDS) management
practices considered, the limitations of these types of systems, and the cost and effectiveness of
these systems.
Nearly 60 documents were reviewed to develop effectiveness and cost data for OSDSs. It should
be noted that the documents obtained and reviewed do not include all of the published literature
regarding OSDS management practices. However, many of the documents obtained were
summaries of other investigations and the most widely used OSDS documents were reviewed.
The influence of soil type, climate, water loads, and separation distance (distance to groundwater
or limiting layer) on OSDS performance are also discussed.
2.1 DESCRIPTION OF OSDS MANAGEMENT PRACTICES
The following is a description of various OSDS management practices.
Conventional Septic System - A conventional septic system consists of a settling or septic tank
and a leaching field. The traditional system accepts both greywater (wastewater from showers,
sinks and laundry) and blackwater (wastewater from toilets). These systems are typically
restricted in that the bottom invert of the leaching field must be at least 2 feet above the
seasonally high water table or impermeable layer (separation distance) and the percolation rate
of the soil must be between 1 and 60 minutes/inch. To ensure proper operation, the tank should
be pumped every 3 to 5 years. Nitrogen removal of these systems is minimal and somewhat
dependent on temperature. The most common type of failure of these systems is from clogging
of the leaching field, insufficient separation distance to the water table, insufficient percolation
capacity of the soil, and over loading of water. Table 2-1 shows estimates of lot areas required
as a function of soil type, assuming that at least 5,000 square feet is needed for a house and its
setbacks.
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Table 2-1: Minimum Lot Sizes Required to Accomodate a Septic Tank Leaching Field
Soil Texture
Perc.Rate
(min/in)
Bottom Area
Application Rate
(gpd/ft2)
Leaching Field
Area
Required"(ft5)
Lot Area Required
incl. 5,000 ft2 for
house (acres)
Gravel, coarse sand
<1
not suitable
not applicable
not applicable
Coarse/medium sand
1-5
1.2
1357
0.2
Fine sand, loam sand
5-15
0.8
2035
0.2
Sandy loam, loam
15-30
0.6
2728
0.25
Loam, porous silt loam
30-60
0.45
3608
0.3
Silty clay loam, clay loam
60-120
0.2
8140
0.5
" Area of leaching field assumes the use of a series of five, 2 ft. wide trenches, spaced 6 ft. apart, and 5 ft. setback
at each edge.
Setbacks are necessary to minimize the threat of public health or environmental problems in case
a system should fail. The setback should be based on soil type, slope, presence and character
of the water table. Setback guidelines should be set for both traditional and alternative OSDS.
EPA recommends the following setbacks for soil absorption systems although other setbacks may
be required for normal high tide marks, pressurized water lines, etc.:
Water Supply Wells:
Surface Waters, Springs:
Escarpments:
Boundary of Property:
Building Foundations:
50 to 100 feet
50 to 100 feet
10 to 20 feet
5 to 10 feet
10 to 20 feet (30 feet when located upslope from a building in
slowly permeable soils.)
Mound Systems - Mound systems operate in much the same manner as conventional septic
systems except that effluent from the septic tank enters a dosing tank and then is pumped to a
leaching field that is located in elevated sand fill above the natural soil surface. This system is
used when insufficient separation distance or percolation conditions exist for a conventional
system. It is maintained and performs in much the same manner as a conventional system. In
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fact, the performance of the system is generally a little better because the pressure dosing
provides for more uniform distribution of effluent throughout the leaching field.
For mound systems, the mound perimeter requires downslope setbacks to make certain that the
basal area of the mound is sufficient to absorb the wastewater before it reaches the perimeter
of the mound to avoid surface seepage. On level sites the entire basal area of the mound (i.e.,
the product of the length of the mound times the width) is used to determine the setbacks. On
sloping sites, only the area downslope of the absorption bed is considered. The exact downslope
setbacks will depend on the permeability of the soil. Upslope and side slope setbacks for sloped
systems should be 10 feet, based on a 3 to 1 side slope.
Where adequate area is available for subsurface effluent discharge, and permanent or seasonal
high ground water is at least 2 feet below the surface, the elevated sand mound may be used in
coastal areas. This system can treat septic tank effluent to a level that usually approaches
primary drinking water standards for BODs, suspended solids, and pathogens by the time the
effluent plume passes the property line for single-family dwellings.
Low Pressure Systems - Low pressure systems are nearly identical to mound systems except that
the leaching field is in natural soil. This system has the same design limitations as a
conventional system and its main advantage is slightly better performance because the pressure
dosing provides for more uniform distribution of effluent throughout the leaching field.
Alternate Trench - As stated in the description of the conventional septic system, the most
common failure is from clogging of the leaching field and/or overloading of water to the field.
Alternate trenches are simply a second leaching field that can be used to rest the primary
leaching field. During the rest period of the primary field, the system reverts to aerobic
clogging and the assimilative capacity of the field is usually improved. Alternate trenches are
typically used 3 to 6 months a year.
Intermittent Sand Filter - Intermittent sand filters are used in conjunction with septic tanks and
leaching fields. An intermittent sand filter receives and treats effluent from the septic tank
before it is distributed to the leaching field. The sand filter consists of a bed (either open or
buried) of granular material from 24 to 36 inches deep. The material is usually from 0.35 to
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1.0 mm in diameter. The bed of granular material is underlain with graded gravel and collector
drains. These systems have been shown to be effective for nitrogen removal, however, this
process is dependent on temperature. Water loading recommendations for these filters is
typically between 1 and 5 gallons per day/square foot (gpd/sf) but can be higher depending on
wastewater characteristics. Primary failure of sand filters is from clogging. The following
maintenance is recommended to keep the system performing properly: resting bed; raking
surface layer; or removing top surface media and replacing it with clean media. In general, the
filters should be inspected every 3-6 months to ensure that they are operating properly.
Intermittent sand filters are used for small commercial and institutional developments and
individual homes. The size of the facility is limited by land availability. The filters should be
buried in the ground, but may be constructed above ground in areas of shallow bedrock or high
water tables. Covered filters are required in areas with extended periods of subfreezing weather.
Excessive long-term rainfall and runoff may be detrimental to filter performance, requiring
measures to divert water away from the system (EPA, 1980).
Recirculating Sand Filter - A recirculating sand filter is nearly identical to an intermittent sand
filter except that effluent from the filter is recirculated through the septic tank and/or the sand
filter again before it is discharged to the distribution field. Recirculating the effluent enhances
performance and allows media size to be increased to as much as 1.5mm in diameter and water
loading rates in the range of 3 to 10 gpd/sf to be used. Recirculation ratios of 3:1 to 5:1 are
generally recommended.
Recirculating sand filters can achieve a very high level of treatment of septic tank effluent before
discharge to surface water or soil. This usually means single-digit figures for BOD5 and
suspended solids and secondary body contact standards for pathogens (in practice, 100-900 per
100 ml). Dosed recycling between sand filter and septic tank or similar devices can result in
significant levels of nitrification/denitrification, equivalent to between 50 and 75 percent overall
nitrogen removal, depending on the recycling ratio. Recirculating sand filters may require as
much as 1 square foot of filter per gallon of septic tank effluent.
Anaerobic Upflow Filter - An anaerobic upflow filter (AUF) resembles a septic tank filled with
3/8-inch gravel with a deep inlet tee and a shallow outlet tee. An AUF system includes a septic
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tank, AUF, a sand filter, and a leaching field. As with the sand filter, dose recycling can be
used to enhance this systems performance. Hydraulic loading for an AUF is generally in the
range of 3 - 15 gpd.
A growing body of data at the University of Arkansas and elsewhere suggests that an upflow
anaerobic filter (UAF) can provide further treatment of septic tank effluent before discharge to
a sand filter. This treatment allows a drastic reduction (by a factor of 8 to 20) in the size of
sand filter needed to attain the performance described above, with major reductions in cost.
An upflow anaerobic filter resembles a septic tank or the second chamber of a dual-chambered
tank. It is filled with 3/8-inch gravel, where wastewater enters at the bottom and exits at the
top. It should be sized to allow retention times between 16 and 24 hours. There is a high
degree of removal of suspended solids and insoluble BOD. Dosed recycling between sand filter
and UAF can result in 60 to 75 percent overall nitrogen removal.
Trenches and Beds - Trenches are typically 1 to 3 feet wide and can be greater than 100 feet
long. Infiltration occurs through the bottom and sides of the trench. Each trench contains one
distribution pipe, and there may be multiple trenches in a single system. Like conventional
septic systems, they require 2 to 4 feet between the bottom of the system and the seasonally high
water table or bedrock, and are best suited in sandy to loamy soils where the infiltration rate is
1 to 60 minutes per inch. Gravelly soils or poor-permeability soils (60 to 90 minutes per inch)
are not suitable for trench systems. However, where the infiltration rate is greater than 1 minute
per inch, 6 inches of loamy soil can be added around the system to create the proper infiltration
rate (Otis, undated).
Beds are similar to trenches except that infiltration occurs only through the bottom of the bed.
Beds are usually greater than 3 feet wide and contain one distribution pipe per bed. Single beds
are commonly used; however, dual beds may be installed and used alternately. The same soil
suitability conditions that apply to trenches apply to bed systems.
Trenches are often preferred to beds for a few reasons. First, with equal bottom areas, trenches
have five times the sidewall area for effluent absorption; second, there is less soil damage during
the construction of trenches; and third, trenches are more easily used on sloped sites.
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The effluent from trenches or beds can be distributed to gravity, dosing, or uniform application.
Dosing refers to periodically releasing the effluent using a siphon or pump after a small quantity
of effluent has accumulated. Uniform application similarly stores the effluent for a short time,
after which it is released through a pressurized system to achieve uniform distribution over the
bed or trench. Uniform application results in the least amount of clogging.
Maintenance of trenches and beds is minimal. Dual trench or bed systems are especially
effective because they allow the use of one system while the other rests for 6 months to a year
to restore its effectiveness (Otis, undated).
Water Separation System - A water separation system separates grey water and blackwater (toilet
waste). The greywater is treated using a conventional septic system and the blackwater is
contained in a vault/holding tank. The blackwater is later hauled offsite for disposal.
For extreme situations or for seasonal residents, some form of separation of toilet wastes from
bath and kitchen wastes may be helpful. Most nitrogen discharges in residential wastewater
come from human urine. A very efficient toilet (0.8 gallon per flush), if routed to a separate
holding tank, would need pumping only three or four times per year even for a family of four
permanent residents.
RUCK System - The RUCK system also requires separation of the greywater and the
blackwater. However the blackwater is nitrified in a buried sand filter and then mixed with the
greywater in an anaerobic tank for denitrification. The effluent is then dosed to a leaching field.
Constructed Wetlands - Constructed wetlands are usually used for polishing of septage effluent
that has already had some degree of treatment. Pretreatment could include processing through
a septic tank or some type of primary and secondary treatment of effluent from a group of
individual properties. Constructed wetlands performance will be degraded in colder climates
during winter months because of plant die off and reduction in the metabolic rate of aquatic
organisms.
Central Sewage Treatment Facility - A central sewage treatment facility would include sewering
of all units to a central facility, and primary, secondary, and tertiary treatment at the facility.
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Cluster Systems - Cluster systems can take on many forms. For this document, a cluster system
is defined as septic systems on individual properties for primary treatment of septage and then
effluent from several of these systems being collected and provided with additional treatment.
The additional treatment could include sand filters or AUF, constructed wetlands, chemical
treatment, or aerobic treatment. The benefit of cluster systems is centralization of the secondary
treatment which can provide some economy of scale in such things as filters or constructed
wetlands.
Evapotranspiration (ED Systems - ET systems combine the process of evaporation from the
surface of a bed and transpiration from plants to dispose of wastewater. The wastewater would
require some form of pretreatment such as a septic tank. An ET bed usually consists of a liner,
drainfield tile, and gravel and sand layers. ET systems are useful where soils are unsuitable for
subsurface disposal, where the climate is favorable to evaporation, and where ground-water
protection is essential. In both types of systems, distribution piping is laid in gravel, overlain
by sand, and planted with suitable vegetation. Plants can transpire up to 10 times the amount
of water evaporated during the daytime. For an ET system to be effective, evaporation must
be equal to or greater than the total water input to the system because it requires an impermeable
seal around the system. In the United States, this limits use of ET systems to the Southwest.
The size of the system depends on the quantity of effluent inflow, precipitation, the local
evapotranspiration rate, and soil permeability (Otis, undated).
Vaults and Holding Tanks - Vaults and holding tanks are used to contain wastewater in
emergency situations or other temporary functions. This technology should be discouraged
because of high anticipated overloads due to difficult pumping logistics. Such systems require
frequent pumping, which can be expensive.
Eliminating Garbage Disposals - Eliminating garbage disposals reduces the waste loads on
OSDSs. The garbage can be composted by the homeowner and the compost has beneficial uses.
Low Phosphate Detergents - Several areas require the use of low phosphate detergents. Low
phosphate detergents have been shown to be as effective in cleaning ability as other detergents.
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Water Conservation Fixtures - Water conservation fixtures can consist of low flush toilets, and
high efficiency shower heads and faucets. There are a variety of fixtures that are commercially
available and their effect on performance of OSDSs can be significant. These modern, high
efficiency fixtures include: 1.5 gallon or less per flush toilets, 2.0 gallon per minute (gpm) or
less shower heads, faucets of 1.5 gpm or less, and front loading washing machines of up to 27
gallons per 10 to 12 pound load. These can result in a 30 to 70 percent reduction of total in-
house water use. In fact, studies have shown that a majority of the failures of conventional
septic systems can be attributed to water overloads.
Fixed Film Systems - A fixed film system employs media to which microorganisms may become
attached. Fixed film systems include trickling filters, upflow filters, and rotating biological
contractors. These systems require pretreatment of septage in a septic tank and the effluent can
be discharged to a leaching field. Data were unavailable on this BMP so its cost and
effectiveness were not evaluated.
Aerobic Treatment Units - Aerobic treatment units can be employed on site. There are a couple
of commercially available packages. However, these systems require regular supervision and
maintenance to be effective. These systems require pretreatment by a septic tank and effluent
can be discharged to a leaching field. Power requirements can be significant for certain types
of these packages. Data were unavailable on this BMP so its cost and effectiveness were not
evaluated.
Disinfection Devices - In some areas, pathogen contamination from OSDS is a major concern.
Disinfection devices may be used in conjunction with the above systems to treat effluent for
pathogens before it is discharged to a soil absorption field. Disinfection devices include halogen
applicators (for chlorine and iodine), ozonators, and UV applicators. Of these three types,
halogen applicators are usually the most practical (EPA, 1980). Installation of these devices in
an OSDS increases the system's cost and adds to the system's operation and maintenance
requirements. However, it may be necessary in some areas to install these devices to control
pathogen contamination of costal waters and ground water.
(NOTE: The use of disinfection systems should be evaluated to determine the potential impacts
of chlorine and iodine loadings. Some States, such as Maryland, have additional requirements
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or prohibit the use of these processes).
General Information - Most septic tanks need to be pumped every three to five years; however,
there are several household factors that need to be considered when determining pumpout needs,
including:
• the capacity of the tank,
• the flow of wastewater (based on family size), and
• the volume of solids in the wastewater (more solids are produced if a garbage
disposal is used) (Mancl and Magette, 1991).
Failure will not occur immediately if a septic system is not pumped; however, continued neglect
will cause the system to fail because the soil absorption system is no longer protected from
solids and may need to be replaced at considerable expense.
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Table 2-2 shows an estimate of how often a septic tank should be pumped based on tank and
household size.
Table 2-2. Suggested Septic Tank Pumping Frequency (Years)
Tank
Size
(gal)
Household Size
(number of people)
1
2
3
4
5
6
7
8
9
10
500
5.8
2.6
1.5
1.0
0.7
0.4
0.3
0.2
0.1
—
750
9.1
4.2
2.6
1.8
1.3
1.0
0.7
0.6
0.4
0.3
1,000
12.4
5.9
3.7
2.6
2.0
1.5
1.2
1.0
0.8
0.7
1,250
15.6
7.5
4.8
3.4
2.6
2.0
1.7
1.4
1.2
1.0
1,500
18.9
9.1
5.9
4.2
3.3
2.6
2.1
1.8
1.5
1.3
1,750
22.1
10.7
6.9
5.0
3.9
3.1
2.6
2.2
1.9
1.6
2,000
25.4
12.4
8.0
5.9
4.5
3.7
3.1
2.6
2.2
2.0
2,250
29.6
14.0
9.1
6.7
5.2
4.2
3.5
3.0
2.6
2.3
2,500
31.9
15.6
10.2
7.5
5.9
4.8
4.0
4.0
3.0
2.6
Source: University of Maryland, 1991.
2.2 EFFECTIVENESS
Data on OSDSs were collected from nearly 60 different documents. Some of these documents
were a little dated but reliable information about removal efficiencies still seemed to be relevant.
In many of the publications, system performance was presented as quality of effluent and not
a percent reduction in pollutant. In these cases, the percent removal was computed by using the
following average household septage pollutant concentrations: Total Suspended Solids (TSS) -
220 mg/1; Biological Oxygen Demand (BOD) - 220 mg/1; Total Nitrogen (TN) - 60 mg/1; Total
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Phosphorous (TP) 25 mg/1, and pathogens - 9 logs. The data that were used to develop these
averages are presented in Section b of the Appendix. The following should be noted about the
above household septage pollutant concentrations:
• The TN value of 375mg/1 reported in Anderson and Machmeir (1988) was
eliminated from consideration because it was deemed to be unrealistically high.
• The TP value of 8 mg/1 reported in EPA (1984) was eliminated from
consideration because it was deemed to be unrealistically low.
• The TP average is based on limited data.
• COD values reported in reference Swanson and Dix (1988) were eliminated from
consideration because they were deemed to be unrealistically low (especially when
compared to the BOD values reported in the same reference).
The following discusses the factors that influence the effectiveness of the various management
practices and also discusses the development of the summary values presented in Table 3-1.
Conventional Septic Systems - The effectiveness values presented in the OSD Cost and
Effectiveness Summary Table were based on the information from 5 references. Nitrogen
removal in these systems can be influenced by temperature. The values assume that the system
is properly maintained (e.g. pumped out every 3-5 years) and that water loading is not
excessive. It should be noted that the effectiveness numbers reported in the literature generally
also considered the assimilative capacity of the soil between the bottom of the leaching field and
the water table.
Mound and Low Pressure Systems - No effectiveness data were obtained from the literature.
However, the effectiveness numbers presented in the summary table were based on these systems
being nearly identical to conventional septic systems. Some increased effectiveness was given
to these systems because the pressure dosing to the leaching field provides a more even
distribution of effluent throughout the field.
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Alternate Trench - No effectiveness data were obtained from the literature. However, the
effectiveness numbers presented in the summary table were based on these systems being nearly
identical to conventional septic systems.
Trenches and Beds - No effectiveness data were obtained from the literature. However, the
effectiveness numbers presented in the summary table were based on these systems being nearly
identical to conventional septic systems.
Anaerobic Upflow Filters - Data reported for AUFs was generally from analysis of effluent from
the filter. Given that in most cases that the effluent is generally also passed through a sand
filter, and the assimilative capacity of the leaching field and soil beneath the field, the total
effectiveness from a system with an AUF would be higher than the numbers presented in the
summary Cost and Effectiveness Table.
Intermittent and Recirculating Sand Filters - These types of filters generally have improved TSS,
BOD, TN and TP removal over conventional systems. It should again be noted that
effectiveness numbers in the literature were generally based on analysis of filter effluent.
Consequently, total system performance should be higher because of the removal that takes place
in the leaching field. TN performance of these types of systems can be effected by temperature,
however in Venhuizen (1991), the investigator concluded that these types of filters would be
very effective in Wisconsin.
Water Separation System - The effectiveness information for these systems is based on data from
4 references. The TP effectiveness would be higher if consideration is given to soil removal
capacity. Additionally, loads from the treatment facility processing the blackwater was not
considered.
RUCK Systems - Most of the data presented in references for RUCK systems concentrated on
nitrogen removal. The other effectiveness data are based on limited information.
Evapotranspiration Systems - Because of the evaporation requirements for these types of
systems, they would only be effective in certain areas of the southwestern portions of the
country. No data on the effectiveness of an operating system's performance were available.
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However, since these systems do not discharge effluent, and assuming that they are maintained
and properly lined, it is estimated that they would be 90% or higher effective at controlling
OSDS pollution.
Constructed Wetlands - The summary of constructed wetlands effectiveness data also considered
data on rock-plant filters. No data were available for TP effectiveness. Additionally, no lower
limit was placed on the TN removal effectiveness because the performance may be severely
impaired during the winter in very cold climates. However, these systems have been installed
in areas such as Michigan, but the majority have been installed in the more mid- and southern-
latitudes of the U.S.
Central Sewage Treatment Facility - Only limited effectiveness information has been included
in the summary Table because performance is dependent on the type of system used. However,
discharges from central facilities are generally regulated under NPDES and the systems
performance must meet these requirements.
Cluster Systems - No effectiveness information has been presented for cluster systems because
the effectiveness strongly depends on the types of treatment given to the effluent once it has been
collected. Effectiveness information could be developed assuming that the collected effluent is
only going to be processed to a leaching field.
Vaults and Holding Tanks - No effectiveness information has been presented for these types of
practices. One could present that they are 100% effective but this would be
-------
OSDS management practices is enhanced.
Disinfection Devices - With proper installation, disinfection devices can be 90% to 99%
effective at eliminating pathogens in OSDS effluents.
2.3 COST
No regional cost variation conclusions could be drawn from the cost data obtained. It is
believed that the cost could vary greatly within a state depending on local cost of living effects
(e.g cost of installing a septic system in rural Garrett County, Maryland as opposed to the
rapidly developing Carroll County, Maryland). The following is a discussion on how the cost
numbers presented in the Cost and Effectiveness Summary Table were determined.
Conventional Septic System - Capital and maintenance costs for these systems varied greatly in
the 6 references that reported cost information. The maintenance cost included the cost of
pumping out the tank every 3 years but did not include inspection costs. It is has been assumed
that homeowners could inspect their own systems with minimal inconvenience.
Mound and Low Pressure Systems - The maintenance costs for these systems is based on the
same septic tank cleaning schedule as for conventional septic systems. However, a slightly
higher maintenance cost is assumed because of maintenance on the pump for the pressure dosing.
Alternate Trench - Depending on the percolation rate and drain field size, the estimated capital
cost of an alternate trench ranges from $2,500 to $5,600. The estimated maintenance cost is $40
a year (Heller et al, 1992).
Trenches and Beds - Depending on the percolation rate and the drain field size, the estimated
capital cost of trenches and beds ranges from $4,900 to $11,100. These cost estimates include
the cost of a 1,000 gallon septic tank, 100 feet of 12 inch plastic perforated pipe, and 35 cubic
yards of soil excavation. The estimated maintenance cost is $40 a year (Heller et al, 1992).
Anaerobic Upflow. Intermittent Sand, and Recirculating Sand Filters - Although the literature
did not include total system costs, the costs presented appeared to include the costs of a septic
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tank and a leaching field. The maintenance costs included replacement of filter media (e.g.
sand) as necessary.
Water Separation System - The only cost information available for this type of system was from
the Draft 6217(g) Guidance Document. It is unclear what the source was for the cost presented
in that document.
RUCK System - Only one reference to cost was available for RUCK systems (Leak, 1986). The
cost number presented in that report was taken from a New Alchemy Institute report on the cost
of a system for Cape Cod ($10,000) and their assessment about what the cost of future systems
may cost ($6,000).
Central Sewage Treatment Facility - The capital cost for these systems was based on the initial
hookup fee for homeowners. It was felt that this would be reasonable even if a new system
were built because the community would attempt to recover the initial construction cost in the
hookup fees. The maintenance costs were based on average yearly user fees to the homeowners
and did not include any cost that may be incurred by the community.
Cluster Systems - The capital cost for these types of systems was based on the per homeowner
hookup fees from two projects (one in New York and one in Michigan). In both of these cases
the homeowners already have septic tanks so that cost has not been included. The maintenance
cost is based on the yearly user fee presented in the New York study.
Evapotranspiration (ET) Systems - The estimated capital cost of an ET system is $19,000. This
cost includes a 1,000 gallon septic tank and a 2,250 square foot drain field. The estimated
maintenance cost is $120 a year (Heller et al, 1992).
Eliminating Garbage Disposals and Use of Low Phosphate Detergents -No costs for these two
source control measures have been included. It is felt that no significant cost would be incurred
by eliminating garbage disposals. Additionally, many manufacturers produce low phosphate
detergents at competitive prices.
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Vaults and Holding Tanks - A fair amount of cost data are available for vaults and holding
tanks. These costs (both capital and maintenance costs) vary greatly with the size of the tank
and the water loading rate. This information should be included in the summary table, however
some careful thought must be given on how to present the costs. The cost of a 2000 gallon tank
may be a useful starting point for calculating capital cost, and maintenance could be computed
based on the average water loading from a 4 person household.
Constructed Wetlands - The costs for constructed wetlands varied greatly. The costs included
land cost and that could explain the wide range ($0.10/gpd to $3.00/gpd). The range of costs
presented in the summary table covers nearly the whole range of costs reported. Minimal
information was available on maintenance costs. The only reported value was for a wetland
serving several households. It may be prudent not to present any values for the maintenance
costs unless more data can be obtained.
Water Conservation Fixtures - No cost data were presented for water conservation fixtures in
the summary table because costs can vary greatly from manufacturer to manufactures and on the
level of fixtures installed (e.g. only low flush toilets). Additionally, savings in water use
charges, size of distribution field, filter, and septic tank should also be considered when
evaluating the total cost of installing these fixtures.
Disinfection Devices - Installation of these devices in an OSDS increases the system's capital
and maintenance costs.
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3.0
OSDS EFFECTIVENESS AND COST SUMMARY TABLE
This section presents quantitative effectiveness and cost summary information for various OSDS
management practices in Table 3-1. The summary table is based on the detailed cost and
effectiveness data presented in Appendix D and E. It should be noted that only practices that
had sufficient quantitative data on which to base conclusions are presented in the Table.
Table 3-1 presents both cost and effectiveness information. The effectiveness information
includes the average, the range observed in the reviewed literature, the probable range expected
from a properly designed and maintained practice, and the number of data values considered in
developing the averages and ranges. The cost information is presented in terms of capital cost
and annual maintenance cost.
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TABLE 3-1.-0SDS EFFECTIVENESS AND COST SUMMARY
i
to
c
S
to
f
0
o.
£
1
- Q
\a *<*
\c a.
w CP
EFFECTIVENESS
COST
PRACTICE
WATER
TSS
BOD
TN
TP
PATH.
CAPITAL
MAINTENANCE
REFERENCES
COST1
COST1
<*)
(,%)
<*)
(%)
(*)
(LOGS)
(S/HOUSE)
(S/YEAR)
CONVENTIONAL SEPTIC
EPA, 1977; EPA, 1980; EPA,
SYSTEM
1989; EPA, 1991; Sandy et al„
Average
NA
72
45
28
57
3.5
$4,500
$70
1988; Lamb et al., 1988;
Probable Range
NA
60-70
40-55
10-45
30-80
3-4
S2,000-S8,000
$50-$ 100
Rhode Island, 1989; Degen et
Observed Range
NA
54-83
3CW0
0-58
0-95
3-4
$2,000-$ 10,000
$25-5110
al., 1991; Healy, 1982; Hanson
No. Values Considered
7
7
13
12
2
8
4
et al., 1988; Dix, 1986;
Fulhage & Day, 1988.
ALTERNATE TRENCH
Heller et al, 1992
Average
NA
NA
NA
NA
NA
NA
NA
NA
Probable Range
NA
60-70
40-55
10-45
30-80
3-4
$2,400-15,600
540
Observed Range
NA
NA
NA
NA
NA
NA
NA
NA
No. Values Considered
0
0
0
0
0
1
1
MOUND SYSTEMS
EPA, 1977; EPA, 1980; EPA,
Average
NA
NA
NA
44
NA
NA
$8,300
5180
1991; Small Flows
Probable Range
NA
60-75
40-60
10-45
30-80
3-4
S7.000-S10.000
5100-5300
Clearinghouse, n.d.; Hanson et
Observed Range
NA
NA
NA
44-44
NA
NA
S6.800-S11,000
590-5310
al., 1988; Degen et al., 1991.
No. Values Considered
0
0
1
0
0
4
4
TRENCHES AND BEDS
Heller et al, 1992
Average
NA
NA
NA
NA
NA
NA
NA
NA
Probable Range
NA
60-70
40-55
10-45
30-80
3-4
S4.900-S11,100
S40
Observed Range
NA
NA
NA
NA
NA
NA
NA
NA
No. Values Considered
0
0
0
0
0
0
1
1
LOW PRESSURE
EPA, 1980; Fulhageand Day,
SYSTEMS
1988.
Average
NA
NA
NA
NA
NA
NA
$5,100
$150
Probable Range
NA
60-70
30-40
10-45
30-80
3-4
$4,000-56000
$100-$200
Observed Range
NA
NA
NA
NA
NA
NA
$2,800-$7,400
$150-$150
No. Values Considered
0
0
0
0
0
0
2
1
ANAEROBIC UPFLOW
EPA, 1991; Venhuizen, 1991;
FILTER
Mitchell, n.d.
Average
NA
44
62
59
NA
NA
$5,550
NA
Probable Range
NA
30-60
50-75
40-75
60-80
3-4
$3,000-58,000
$150-$400
Observed Range
NA
24-89
46-84
20-75
NA
NA
$3,000-58,000
NA
No. Values Considered
0
6
6
6
0
0
2
0
-------
TABLE 3-1. OSDS EFFECTIVENESS AND COST (Continued)
LO
i
Ui
c
n
to
S
Cl
NO
VO o.
U) ct
EFFECTIVENESS
COST
PRACTICE
WATER
TSS
BOD
TN
TP
PATH.
CAPITAL
MAINTENANCE
REFERENCES
COST1
COST1
(#)
C%)
(%)
(%)
<*)
(LOGS)
(S/HOUSE)
¦ (S/YEAR)
INTERMITTENT SAND
EPA, 1977; EPA, 1980; EPA,
FILTER
1991; Small Flows
Average
NA
92
92
55
80
3.2
$5,400
$275
Clearinghouse, n.d.;
Probable Range
NA
80-95
90-95
50-65
70-90
3-4
S4.000-J8.000
$2J0-$400
Venhuizen, 1991.
Observed Range
NA
70-99
80-99
40-75
70-90
2-4
$2,300-$ 10,000
$100-$440
No. Values Considered
0
7
10
7
2
6
7
5
RECIRCULATING SAND
Hoxieetal., 1988; Small
FILTER
Flows Clearinghouse, n.d.;
Average
NA
90
92
64
80
2.9
$3,900
$140
Fulhage A. Day, 1988; EPA,
Probable Range
NA
85-95
85-95
60-85
70-90
2-4
$5,000-$8,000
$250-$400
1991; Venhuizen, 1991;
Ob»erved Range
NA
70-98
75-98
1-94
70-90
2-4
$l,850-$7,500
$15-5410
Swanson& Dix, 1988; Lamb
No. Values Considered
0
12
15
13
2
8
8
7
et a!., 1988; Laak, 1986; EPA,
1980; Sandy et al., 1988.
RUCK SYSTEM
Laak, 1986; Lamb et al., 1988;
Average
NA
85
86
51
83
4
$14,000
NA
EPA, 1991.
Probable Range
NA
80-90
80-90
50-80
70-90
3-4
$12,000-S16,000
$250-$400
Observed Range
NA
85-85
86-86
6-80
83-83
4-4
$12,000-$ 16,000
NA
No. Values Considered
0
1
1
5
1
1
1
0
WATER SEPARATION
EPA, 1991; EPA, 1986; EPA,
SYSTEM
1980; EPA, 1977.
Average
NA
60
42
83
30
3
$8,000
$300
Probable Range
NA
55-70
35-55
70-90
30-55
2-4
$5,000-$11,000
$300-$750
Observed Range
NA
36-75
22-55
68-99
14-42
NA
$5,000-$ 11,000
$300-5300
No. Values Considered
0
4
3
6
6
0
1
1
CONSTRUCTED
Reed, 1991; Small Flows
WETLANDS
Clearinghouse, n.d., EPA,
Average
NA
80
81
90
NA
4
$710
$25
1980; Amberg, 1990; Dwyeret
Probable Range
NA
60-90
70-90
60-90
30-70
3-4
$1,000-$3,000
$25-$I00
al., 1989.
Observed Range
NA
50-98
65-97
90-90
NA
4-4
$50-$350
$25-$25
No. Values Considered
0
3
4
2
0
1
19
1
-------
TABLE 3-1. OSDS EFFECTIVENESS AND COST (Continued)
I
¦P*
g I
g |
^ I
N> H
>^1 Q.
Q
VO vT
VO Q-
U> CD
EFFECTIVENESS
COST
PRACTICE
WATER
TSS
BOD
TN
TP
PATH.
CAPITAL
MAINTENANCE
REFERENCES
COST1
COST'
w
<%)
w
<%)
(*)
(LOGS)
(5/HOUSE)
(S/YEAR)
CENTRAL SEWAGE
Orr, 1989; EPA, 1980;
TREATMENT FACILITY
Decker, 1987.
Average
NA
85
85
NA
NA
NA
55,450
$180
Probable Range
NA
80-90
80-90
75-95
30-70
3-4
$3,000-510,000
$150-$250
Obaerved Range
NA
85-85
85-85
NA
NA
NA
$40-59,977
$70-$240
No. Values Considered
0
1
1
0
0
0
4
3
CLUSTER SYSTEMS
Decker, 1987; Small Flows
Average
NA
NA
NA
NA
NA
NA
$4,950
$370
Clearinghouse, n.d.
Probable Range
NA
NA
NA
NA
NA
NA
$5,000-$7,000
$300-$400
Observed Range
NA
NA
NA
NA
NA
NA
$3,000-$6,900
5370-5370
No. Values Considered
0
0
0
0
0
0
3
1
EVAPOTRANSPIRATION
Heller etsl, 1992
SYSTEM
Average
NA
NA
NA
NA
NA
NA
NA
NA
Probable Range
NA
95-100
95-100
95-100
95-100
3-4
$19,000
5120
Observed Range
0
NA
NA
NA
NA
NA
NA
NA
No. Values Considered
0
0
0
0
0
0
0
ELIMINATING GARBAGE
EPA, 1991; EPA, 1986; EPA,
DISPOSALS
1980.
Average
NA
37
28
5
2.5
NA
NA
NA
Probable Range
NA
35-40
25-30
5-10
2-3
NA
Negligible
Negligible
Observed Range
NA
37-37
28-28
5 5
2-3
NA
NA
NA
No. Values Considered
0
3
2
2
2
0
0
0
LOW PHOSPHATE
EPA, 1991; EPA, 1980.
Detergents
Average
NA
NA
NA
NA
50
NA
NA
NA
Probable Range
NA
NA
NA
NA
40-50
NA
Negligible
Negligible
Observed Range
NA
NA
NA
NA
50-50
NA
NA
NA
No. Values Considered
0
0
0
0
2
0
0
0
-------
TABLE 3-1. OSDS EFFECTIVENESS AND COST (Continued)
EFFECTIVENESS
COST
PRACTICE
WATER
TSS
BOD
TN
TP
PATH.
CAPITAL-
MAINTENANCE
REFERENCES
COST'
COST'
(%)
(%)
(%)
(*>
(%)
(LOGS)
($/HOUSE)
(S/YEAR)
WATER CONSERVATION
EPA, 1991; EPA, 1980; EPA,
FIXTURES
1977; Small Flows
Average
45
NA
NA
NA
NA
NA
NA
NA
Clearinghouse, n.d.; Jarrett et
Probable Range
25-80
NA
NA
NA
NA
NA
Varies
Negligible
al„ 1985.
Observed Range
4-90
NA
NA
NA
NA
NA
NA
NA
No. Values Considered
11
0
0
0
0
0
0
0
HOLDING TANKS
Small Flows Clearinghouse,
Average
NA
NA
NA
NA
NA
NA
$3,900
$1,300
n.d.; Dix, 1986; Hanson et al.,
Probable Range
NA
95-100
95-100
95-100
95-100
3-4
S4,000-56,000
SI,000-$2,000
1988.
Observed Range
NA
NA
NA
NA
NA
NA
$1,220-56,670
$100-52,400
No. Values Considered
0
0
0
0
0
0
8
12
i
LA
e o
2? 2-
<
i
Cu
^ Q
VO CT
so Cu
Ui
'Cost are in 1988 equivalent dollars and an average household with 4 occupants was assumed.
-------
4.0
MANAGEMENT PRACTICE OPTIONS
This section presents management practices options that were deemed, based on the literature
review, technically and economically achievable for control of NPS pollution from OSDSs in
the coastal zone. In general, new OSDSs should be designed, installed, operated, and
maintained to prevent the discharge of pollutants to the surface of the ground and minimize the
discharge of pollutants into ground water. A few conditions that should be met for all new
OSDSs are the use of low-volume plumbing fixtures and the prohibition of the installation of
garbage disposals. OSDSs that minimize nitrogen loadings to ground water should be used in
areas where conditions indicate that nitrogen-limited coastal waters may be adversely affected
by excess nitrogen loadings from OSDSs. The OSDS management practice options are presented
in two sections, one for new OSDSs and one for replacement or enhancement of existing
OSDSs.
4.1 NEW OSDSs
1. Conventional Septic System with Alternate Trench and Water Conservation
Fixtures. Low Phosphate Detergents, and No Garbage Disposals
Description: Septic systems have been widely used as an OSDS practice. A septic
system can be effective if it is installed with an alternate trench to the leaching field and
if water conservation fixtures are installed in the house. An alternate trench is
recommended so that the primary leaching field can be rested for 3 to 6 month intervals
on a yearly basis. This will ensure that aerobic conditions are maintained in the soil
below the leaching field. The majority of conventional septic system failures are due to
water overload. Consequently, water conservation fixtures should also be installed in
conjunction with the system. Finally, garbage disposals can be eliminated and low
phosphate detergents can be employed at very minimal cost and can significantly reduce
the waste loads to the system.
Maintenance: The conventional septic system should be inspected yearly, the septic tank
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should be cleaned out every 3 years, and the alternate trench should be used for 3 to 6
months each year.
Limitations: Conventional septic systems should not be used if the following conditions
are present:
• Unsuitable site areas such as poorly or excessively drained soils (e.g.
percolation rate less than 5 min/inch or greater than 120 min/inch), areas
with shallow and/or rising water tables (e.g. depth to groundwater or
limiting layer less than 2 feet), areas overlaying fractured bedrock that
drain directly to ground water, areas within floodplains, or areas where
effluent cannot be sufficiently treated before it reaches sensitive
waterbodies, including ground or surface water.
• Nitrogen-limited coastal waters that may be adversely affected by excess
nitrogen loadings from conventional OSDS exist.
Regional Factors: Conventional septic systems can be applied in every region of the
country provided the above design limitations are not violated. There may be some
slightly less effectiveness with regard to nitrogen removal in colder climates. However,
these differences would be overshadowed by the variability in the performance of the
systems based on differences in soil type within one region.
2. Mound Systems with Water Conservation Fixtures. Low Phosphate Detergents,
and No Garbage Disposals
Description: This mound system would essentially function the same as the septic system
described in 1. above with the notable exception that the leaching field would be elevated
in a sand mound and pressure dosing would be used for discharging effluent to the
leaching field. The effectiveness would be very similar to the septic system described
above. Mound systems can be used when there is insufficient separation distance for a
conventional septic system. Water conservation fixtures and low phosphate detergents
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should be used in conjunction with the mound system and the use of garbage disposals
should be prohibited.
Maintenance: The system should be inspected yearly, the septic tank should be cleaned
out every 3 years, and there should be routine maintenance of the dosing pump.
Limitations: Mound systems should not be used if the following conditions are present:
• Unsuitable site areas such as poorly or excessively drained soils (e.g.
percolation rate less than 5 min/inch or greater than 120 min/inch), areas
overlaying fractured bedrock that drain directly to ground water, areas
within floodplains, or areas where effluent cannot be sufficiently treated
before it reaches sensitive waterbodies, including ground or surface water.
• Nitrogen-limited coastal waters that may be adversely affected by excess
nitrogen loadings from conventional OSDS exist.
Regional Factors: Mound systems can be applied in every region of the country
provided the above design limitations are not violated. There may be some slightly less
effectiveness with regard to nitrogen removal in colder climates. However, these
differences would be overshadowed by the variability in the performance of the systems
based on differences in soil type within one region.
3. Anaerobic. Intermittent Sand, or Recirculating Sand Filter in Conjunction with
Septic Tank. Leaching Field. Water Conservation Fixtures. No Garbage Disposals
and Low Phosphate Detergent
Description: In areas with known or suspected nitrate problems, or in areas with
excessively drained soils (e.g. percolation rates are less than 5 min/inch), denitrifying
devices such as anaerobic, intermittent sand, or recirculating sand filters should be used
in conjunction with a conventional type septic system. These filters greatly enhance the
nitrogen removal from septage (50 to 60% more effective than septic system alone). The
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type of filter selected can be based on local cost with the recirculating sand filter having
slightly better performance than the intermittent sand or anaerobic upflow filters. Again,
water conservation fixtures and low phosphate detergents should be used and garbage
disposals should be prohibited.
Maintenance: Inspect system yearly, pump out septic tank every 3 years, replace sand
as needed, and perform routine maintenance on pumps.
Limitations: Septic systems with one of the filters described above should not be used
if the following conditions are present:
• Unsuitable site areas such as poorly drained soils (e.g. percolation rate
greater than 120 min/inch), areas with shallow and/or rising water tables
(e.g. depth to groundwater or limiting layer less than 2 feet), areas
overlaying fractured bedrock that drain directly to ground water, areas
within floodplains, or areas where effluent cannot be sufficiently treated
before it reaches sensitive waterbodies, including ground or surface water.
Regional Factors: These types of systems can be applied in every region of the country
provided the above design limitations are not violated. There may be some slightly less
effectiveness with regard to nitrogen removal in colder climates. However, field studies
have shown these differences to be very small even in the most northern latitudes.
4. Constructed Wetlands or Evapotranspiration Systems
Description: In areas with known or suspected nitrate problems, or in areas with poorly
drained soils (e.g. percolation rates are greater than 120 min/inch), or where there is an
insufficient separation distance (e.g. less than 2 feet to ground water or limiting layer),
constructed wetlands or evapotranspiration systems should be used in conjunction with
a conventional septic tank. The selection of either a constructed wetland or an
evapotranspiration system will depend on the region of the country, available land, and
cost. Again, water conservation fixtures and low phosphate detergents should be used
Onsite Sanitary Disposal Systems
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and garbage disposals should be prohibited.
Maintenance: Inspect system yearly, pump out septic tank every 3 years, harvest plants
from wetlands as needed, and perform routine maintenance on pumps.
Limitations: Constructed wetlands or evapotranspiration systems should not be used if
the following conditions are present:
• Unsuitable site areas such as areas within floodplains, or areas where
effluent cannot be sufficiently treated before it reaches sensitive
waterbodies, including ground or surface water.
Regional Factors: Constructed wetland systems can be applied in every region of the
country provided the above design limitations are not violated. There may be some
slightly less effectiveness with regard to nitrogen removal in colder climates. However,
field studies have shown these differences to be very small even in the most northern
latitudes. Because of the high potential evapotranspiration rates needed,
evapotranspiration systems can only be applied in the southwestern portion of the
country.
4.2 REPLACEMENT OR ENHANCEMENT OF EXISTING OSDSS
This section assumes that the system that is being replaced or enhanced is a conventional
septic system. If a system is being replaced, the management practices described in
Section 4.1. above should be employed as appropriate. If a septic system is failing or
if there are water quality problems due to septic systems (e.g. high nitrate concentrations
in groundwater) then the following management practices should be considered.
1. Install Water Conservation Fixtures with an Alternate Trench. Low Phosphate
. Detergents, and No Garbage Disposals
As stated previously, the majority of all conventional septic system failures are due to
water overloads. Water conservation fixtures with use of alternate trenches have been
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shown to correct failing septic systems in certain situations. Using low phosphate
detergents and eliminating the use of garbage disposals should also be employed where
the conventional septic system is failing. The alternate trench should be used a minimum
of 3 months per year and its initial use should be until aerobic conditions have been
restored in the original leaching field.
2. Install Anaerobic Upflow. Intermittent Sand, or Recirculating Sand Filters in
Areas with Nitrogen Problems in Groundwater
In areas where high nitrogen concentrations are found in groundwater and where the
source of the nitrogen has been attributed to conventional septic systems, the above
mentioned filter systems should be installed. Water conservation fixtures should also be
installed, low phosphate detergent should be used, and the use of garbage disposals
eliminated.
3. Install Constructed Wetlands or Evapotranspiration Systems
In areas with failing septic systems due to either poorly drained (e.g. percolation rate
greater than 120 min/in.) or insufficient separation distance (e.g. less than 2 feet to
ground water or limiting layer) constructed wetlands or evapotranspiration systems should
be installed. Again, water conservation fixtures and low phosphate detergents should be
used in conjunction with the elimination of garbage disposals.
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5.0
REFERENCES
Alabama Dept. of Public Health. 1988. Rules of State Board of Health and Onsite Sewage
Disposal.
Amberg, L.W. 1990. Rock-Plant Filter An Alternative for Septic Tank Effluent Treatment.
U.S. EPA.
American Society of Agricultural Engineers. 1988. On-Site Wastewater Treatment Vol. 5.
Proceedings of the Fifth National Symposium on Individual and Small Community
Sewage Systems. (Chicago, Illinois. December 14-15, 1987.) ASAE. Publication No.
10-87.
Anderson, J.L. and R.E. Machmeier. 1988. "Establishment of State Rules for Land
Application and Utilization of Septage." On-Site Wastewater Treatment Vol. 5.
Proceedings of the Fifth National Symposium on Individual and Small Community
Sewage Systems. (Chicago, Illinois. December 14-15% 1987.) ASAE. Publication No.
10-87. p. 68-76.
Bailey, R., et. al. 1988. "Long-Term Performance of a Pressure Dosed Septic Tank Filter
Field." On-Site Wastewater Treatment Vol. 5. Proceedings of the Fifth National
Symposium on Individual and Small Community Sewage Systems. (Chicago, Illinois.
December 14-15, 1987.) ASAE Publication No. 10-87. pp. 114-121.
Barnstable Count Health and Environmental Department. 1991. Material Concerning Proposed
Board of Health Regulations.
California Water Resources Control Board. 1989. Onsite Septic System Regulation.
Chesapeake Bay Foundation. Date Unknown. Septic Systems and the Bay.
Onsite Sanitary Disposal Systems
80040000H:\wp\report\osd\report 1 .osd
5-1
Woodward-Clyde
January 27, 1993
-------
Converse, J., et. al. 1988. "The Wisconsin At-Grade Soil Absorption System for Septic Tank
Effluent." On-Site Wastewater Treatment Vol. 5. Proceedings of the Fifth National
Symposium on Individual and Small Community Sewage Systems. (Chicago, Illinois.
December 14-15, 1987.) ASAE Publication No. 10-87. pp. 114-121.
Decker, R.W. 1987. Crystal Lake Life or Death. Board of Public Works, Benzie County, MI.
Delaware DNR. 1990. Delaware Inland Bays Recovery Initiative. Delaware DNR.
Dix, S.P. 1986. Case Study No. 4 Crystal Lakes. Colorado. EPA/National Small Flows
Clearinghouse.
Dwyer, T. and K. Sylvester. 1989. "Natural Processes for Tertiary Treatment of Municipal
Wastewater Coupled with Shallow Ground-Water Discharge in a Saltwater Marsh
Environment." Proceedings of Groundwater Issues and Solutions in the Potomac River
Basin/Chesapeake Bay Region (Washington, DC. March 14-16, 1989.) NWWA.
Friebele, E. 1989. Present and Potential Impacts on Ground Water in the Potomac River Basin
in Maryland. Interstate Commission on the Potomac River Basin.
Frimpter, M.H., J.J. Donohue, and M.V. Rapacz. 1988. The Cape Code Aquifer Management
Project (CDAMP) A Mass Balance Nitrate Model for Predicting the Effects of Land Use
on Groundwater Quality in Municipal Wellhead Protection Areas. U.S. EPA Region I,
U.S.G.S., Mass. Department of Env. Qual. Engineering, Cape Cod Planning and
Economic Development Commission.
Fulhage, C.D. and D. Day. 1988. "Design, Installation and Operation of a Low Pressure Pipe
Sewage Absorption System in the Missouri Claypan Soil." On-Site Wastewater Treatment
Vol. 5. Proceedings of the Fifth National Symposium on Individual and Small
Community Sewage Systems. (Chicago, Illinois. December 14-15, 1987.) ASAE
Publication No. 10-87. pp. 114-121.
Onsite Sanitary Disposal Systems
80040000H:\wp\report\osd\report 1. osd
5-2
Woodward-Clyde
January 27, 1993
-------
Gunn, I. 1988. "Lehigh Laboratory Evapo-Transpiration System." On-Site Wastewater
Treatment Vol. 5. Proceedings of the Fifth National Symposium on Individual and Small
Community Sewage Systems. (Chicago, Illinois. December 14-15, 1987.) ASAE
Publication No. 10-87. pp. 114-121.
Hanson, M.E. and H.M. Jacobs. 1987. "Land Use and Cost Impacts of Private Sewage System
Policy in Wisconsin." On-Site Wastewater Treatment Vol. 5. Proceedings of the Fifth
National Symposium on Individual and Small Community Sewage Systems. (Chicago,
Illinois. December 14-15, 1987.) ASAE Publication No. 10-87. pp.26-39.
Heller, K.B., K.E. Mathews, R.A. Cushman, E.S. Newbold, and T. Applegate. May 1992.
Economic Analysis of Coastal Nonpoint Source Controls: Urban Areas.
Hydromodifications. and Wetlands - Draft. Research Triangle Institute. Prepared for
USEPA.
Hopkins, M. Date Unknown. "Sewage Disposal System Makes Residents See Red."
Broadneck Newspaper.
Horsely Witten Hegeman, Inc. 1991. Qualification and Control of Vitroga Inputs to Buttermilk
Bay. Vol. 1.
Hoxie, D.C., R.G. Martin and D.P. Rocque. 1988. "A Numerical Classification System To
Determine Overall Site Suitability for Subsurface Wastewater Disposal." On-Site
Wastewater Treatment Vol. 5. Proceedings of the Fifth National Symposium on
Individual and Small Community Sewage Systems. (Chicago, Illinois. December 14-15,
1987.) ASAE Publication No. 10-87. pp. 366-374.
Institute of Environmental Negotiation. 1991. Report of the Virginia Task Force on Septic
Regulations. University of Virginia.
Jarrett, A.R., D.D. Fritton, and W.E. Sharpe. 1985. Renovation of Failing Absorption Fields
by Water Conservation and Resting. ASAE. Paper No. 85-2630.
Onsite Sanitary Disposal Systems
80040000H:\wp\report\osd\reportl .osd
5-3
Woodward-Clyde
January 27, 1993
-------
Laak, R. 1986. RUCK Systems Environmentally Efficient Modern On-Site Wastewater
Technology.
Lamb, B., A.J. Gold, G. Loomis and C. McKiel. 1988. "Evaluation of Nitrogen Removal
Systems for On-Site Sewage Disposal." Qn-Site Wastewater Treatment Vol. No. 5.
Proceedings of the Fifth National Symposium on Individual and Small Community
Sewage Systems. (Chicago, Illinois. December 14-15, 1987.) ASAE Publication No.
10-87. pp. 151-160.
Logsdon, G. 1990. "Greenhouse Industry Breakthrough: Plant Protection Through
Compost." Biocvcle Journal, pp. 52-54.
Maclntyre, W., et. al. 1989. "Groundwater Non-Point Sources of Nutrients to the Southern
Chesapeake Bay." Proceedings of the Conference on Groundwater Issues and Solutions
in the Potomac River Basin/Chesapeake Bay Region. NWWA.
Mancl, K. and W. Magette. 1991. Maintaining Your Septic Tank. Water Resources 28.
Cooperative Extension Service, Univesity of Maryland, College Park, MD.
Mitchell, D. Date Unknown. "Laboratory and Prototype Onsite Denitrification by an Anaerobic
- Aerobic Fixed Film System WWPCRE11" University of Arkansas.
North Carolina Dept. of Env. Health and Nat. Resources. 1991. Laws and Rules for Sanitary
Sewage Collection Treatment and Disposal.
Orr, R. 1989. "Septic Tank Effluent Collection and Sand Filter Treatment." Case Study 18
New York State I/A Technology Evaluation Report No. 8. New York State Dept. Of
Environmental Conservation.
Otis, R.J. 1983. "State of Vermont Wastewater Treatment and Disposal - Individual Onsite
Systems WWPCDM19." Vermont Health Regulations Chapter 5. Sanitary Engineering.
Subchapter 10. State of Vermont, Agency of Human Services.
Onsite Sanitary Disposal Systems
80040000H:\wp\report\osd\reportl .osd
5-4
W ood ward-Clyde
February 1, 1993
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Otis, R.J. Date Unknown. Onsite Wastewater Treatment - Septic Tanks. Rural Systems
Engineering.
Reed, S.C. 1991. "Constructed Wetlands for Wastewater Treatment." BioCvcle: Journal of
Waste Recycling.
Reneau, R. 1977. "Changes in Organic Nitrogenous Compounds from Septic Tank Effluent in
a Soil with Fluctuating Water Table." Journal of Environmental Quality.
Ritter, W. 1986. Nutrient Budgets for the Inland Bays.
Rhode Island, Land Management Project. 1989. Nitrate Ntrogen Pollution from Septic systems:
and Phosphorus Pollution from Septic Systems. U.S. EPA, Land Management Project.
Sandy, A.T., W.A. Sack and S.P. Dix. 1988. "Enhanced Nitrogen Removal Using a Modified
Recirculating Sand Filter (RSF2)." On-Site Wastewater Treatment Vol. 5. Proceedings
of the Fifth National Symposium on Individual and Small Community Sewage
Systems. (Chicago, Illinois. December 14-15, 1987.) ASAE Publication No.
10-87. pp. 161-170.
Sawka, G., et. al. 1988. "Evaluation of Florida Soils for Onsite Disposal Systems." On-Site
Wastewater Treatment Vol. 5. Proceedings of the Fifth National Symposium on
Individual and Small Community Sewage Systems. (Chicago, Illinois. December 14-15,
1987.) ASAE Publication No. 10-87. pp. 161-170.
Schutz, F.R. 1990. "Constructed Wetlands Growing Throughout U.S." Small Flows Vol. 4.
No. 6. National Small Flows Clearinghouse, WVU. Vol. 4, No. 6.
Sherman, K.M., D.L. Anderson, D.L. Hargett, R.J. Otis and J.C. Heber in. 1988. "Florida's
Onsite Sewage Disposal System (OSDS) Research Project." On-Site Wastewater
Treatment Vol. No. 5. Proceedings of the Fifth National Symposium on Individual and
Small Community Sewage Systems. Chicago, Illinois. December 14-15, 1987.) ASAE
Publication No. 10-87. pp. 47-56.
Onsite Sanitary Disposal Systems Woodward-Clyde
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5-5
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Small Flows Clearinghouse, West Virginia University, editors. 1991. "Very Low Flush Toilets
WWBKGN09." (Product Information from Various Vendors.) SFC, WVU.
Small Flows Clearinghouse, West Virginia University, editors. Date Uknown. "On-Site
Systems." (A Series of Fact Sheets.) SFC, WVU.
Small Flows Clearinghouse, West Virginia University, editors. Date Uknown. "Introduction
Package on Sand Filters." SFC, WVU.
South Carolina Dept. of Health and Environment. 1986. Regulation for Conventional and
Alternative Individual Waste Disposal Systems.
Swanson, S.W. and S.P. Dix. "On-Site Batch Recirculation Bottom Ash Filter Performance."
On-Site Wastewater Treatment Vol. No. 5. Proceedings of the Fifth National Symposium
on Individual and Small Community Sewage Systems. (Chicago, Illinois. December 14-
15, 1987.) ASAE Publication No. 10-87. pp. 132-141.
U.S. EPA. 1991. "A Method for Tracing On-Site Effluent from Failing Septic Systems." EPA
Nonpoint Source News Notes. EPA-OWOW.
U.S. EPA. 1991. Proposed Guidance Specifying Management Measures for Sources of
Nonpoint Pollution in Coastal Waters. EPA-OWOW.
U.S. EPA. 1990. Buzzards Bay Comprehensive Conservation & Management Plan.
U.S. EPA. 1989(a). Septic Systems. Office of Water, The Land Management Project.
U.S. EPA. 1989(b). Process Design Manual Land Treatment of Municipal Wastewater, with
the USACE, USDA, and Dept. of Interior.
U.S. EPA. 1989(c). Research Review: Nitrate Nitrogen Pollution from Septic Systems.
Office of Water, The Land Management Project.
Onsite Sanitary Disposal Systems
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U.S. EPA. 1989(d). Research Review: Phosphorus Pollution from Septic Systems. Office of
Water, The Land Management Project.
U.S. EPA. 1986. Septic Systems and Groundwater Protection: A Program Manager's Guide
and Reference Book. Office of Water.
U.S. EPA. 1984. Handbook: Septage Treatment and Disposal. Water Planning Division.
Municipal Env. Research Lab, CERI.
U.S. EPA. 1980. Design Manual - Onsite Wastewater Treatment and Disposal Systems.
Office of Water.
U.S. EPA. 1977. Alternatives for Small Wastewater Treatment Systems (Volumes 1. 2 and 31.
EPA Technology Transfer Seminar Publication.
Venhuizen, D. 1991. Town of Washington. WI Wastewater System Feasibility Study -
Exploration of Treatment Technology and Disposal System Alternatives. WI DNR.
Virginia Department of Health. Date Uknown. Alternative Discharging Sewage Treatment
System.
Virginia Department of Health. 1989. Sewage and Handling and Disposal Regulations.
Yahner, J., et. al. 1988. "Summary of a 5-Year Monitoring Effort of Alternative Systems in
Indiana." On-Site Wastewater Treatment Vol. 5. Proceedings of the Fifth National
Symposium on Individual and Small Community Sewage Systems. (Chicago, Illinois.
December 14-15, 1987.) ASAE Publication No. 10-87. pp. 114-121.
Yates, M. 1987. Septic Tank Siting to Minimize the Contamination of Groundwater by
Microorganisms. EPA Office of Water.
Yates, M., 1985. "Septic Tank Density and Ground Water Contamination." Ground Water.
Onsite Sanitary Disposal Systems
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APPENDICES
-------
APPENDIX A
STATE REGULATIONS
-------
SUMMARY OF STATE SEPTIC SYSTEM REGULATIONS
LOCATON
PERC. RATE
SET BACKS FROM BODIES
OF WATER
SEPARATION DISTANCE
(SHWT)
Alaska
4'
American Samoa
Alabama
5-60 min./inch
50'
1.5'
California
Region I
60 min./inch
50 - 100'
5 - 40'
Region II
100'
U\
1
o
Connecticut
1.5'
Delaware
6-60 min./inch
50'(Body of water)
100'(Wetland)
3'
Florida
Use soil classification to
determine sizing of system
75'
2'
Georgia
50-90 min./inch
50'(Leach Field)
25'(Septic Tank)
T
Guam
Hawaii
10-30 min./inch
50'
3'
Indiana
50 - 100'
Louisiana
20 min./inch
2'
Maine
100'
1 -2'
Maryland
5-30 min./inch
25'
4'(May be waived but requires
groundwater protection ?)
A-l
-------
LOCATON
PERC. RATE
SET BACKS FROM BODIES
OF WATER
SEPARATION DISTANCE
(SHWT)
Massachusetts
(Clint Watson)
1-30 min./inch
25'(Septic Tank)
50'(Leach Field)
4'
Michigan
30-60 min./inch
50'
4'
(Minnesota)
0.1 min./inch - 60 min./inch
3'
Mississippi
Use soil evaluation instead of
perc. test
Slope greater than 8% = 100'
Slope less than 8% - 50'
2' if no layer within 5'
2' if layer within 5'
North Carolina
None
50 - 100*
1'
New Hampshire
1-60 min./inch
75'
4'
New Jersey
2 - 9'
New York
1-60 min./inch
100'(Leach Field)
50'(Septic Tank)
2'
Northern Marianas
(Ohio)
4*
Oregon
0.5'
Pennsylvania
4'
Puerto Rico
4'
Rhode Island
3'
South Carolina
None
50'
0.5'
Virginia
5-120 min./inch
50'
70'(Shellfish Water)
0.17 - 1.67'
Virgin Islands
A-2
-------
LOCATON
PERC. RATE
SET BACKS FROM BODIES
OF WATER
SEPARATION DISTANCE
(SHWT)
Washington
3'
Wisconsin
3'
A-3
-------
APPENDIX B
RESIDENTIAL SEPTAGE POLLUTANT LOADS
-------
RESIDENTIAL SEPTAGE POLLU
TANT LOADS
ST
STUDY
WATER
TSS
BOD
CO
D
TN
TP
PATHO.
REFERENCE
TYPE
LOAD
LOW
HI
LOW
HI
LOW
HI
LOW
HI
LOW
HI
LOW
HI
GPD
mg/l
mcj/'
mcj/l
mg/l
mfl/l
mR/l
mcj/l
ma/I
mcj/l
mH/l
LOGS
LOGS
MA
MODEL
200
35
40
Frimpter et. al., 1988
R!
30
80
EPA, 1989(a)
NAT.
200
EPA, 1986
Ml
IN—SITU
200
Decker, 1987
MD
IN-SITU
220
220
Dwyeret. al., 1989
WV
IN-SITU
175
45
102
95
250
30
80
Swanson and Dix, 1988
MN
IN-SITU
375
8
Anderson & Machmeier, 1988
WV
IN-SITU
100
42
83
Hoxie et. al., 1988
NAT.
240
200
290
200
290
680
730
35
100
18
29
8
10
EPA,1980
NAT.
220
220
500
65
8
8
10
EPA, 1984
335
264
120
25
EPA,1977
AVERAGE
183
202
220
637
95
20
8.8
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B-1
January 29, 1993
-------
APPENDIX C
IMPLEMENTATION RESTRICTIONS
-------
IMPLEMENTATION RESTRICTIONS
PRACTICE
WATER
LOADING
DEPTH TO
WATER TABL1
INFILTRATION/
PERC RATE
OTHER
REFERENCE
LOW
FT
HI
FT
LOW
MIN/IN
HI
MIN/IN
ANAER. UPFLOW FILT
ANAER. UPFLOW FILT
2.13-8.53*
8-15*
Venhuizen, 1991
Venhuizen, 1991
AVERAGE
RANGE
8
2-15
INTER. SAND FILTER
INTER. SAND FILTER
1-5**
< 1**
0.35-1.0 MM MAT.
0.5-1.0 MM MAT.
Small Flows Clearing House
EPA, 1980
AVERAGE
RANGE
2.3
1 - 5
MOUND SYSTEM
MOUND SYSTEM
NA
NA
2
3
5
0
120
120
PUMP 3-5 YR
Small Flows Clearing House
EPA, 1980
AVERAGE
RANGE
3.3
2-5
80.0
0 - 120
RECIRC. SAND FILTER
RECIRC. SAND FILTER
RECIRC. SAND FILTER
RECIRC. SAND FILTER
RECIRC. SAND FILTER
RECIRC. SAND FILTER
3-5**
3-5**
5-13.8**
5-10**
7.5-9**
3-5**
0.3-1.5 MM MAT.
INSPECT EACH YR
0.3-1.5 MM MAT.
EPA, 1980
Small Flows Clearing House
Venhuizen, 1991
Small Flows Clearing House
Venhuizen, 1991
Small Flows Clearing House
AVERAGE
RANGE
6.2
3 - m
SEPTIC SYSTEM
SEPTIC SYSTEM
SEPTIC SYSTEM
SEPTIC SYSTEM
SEPTIC SYSTEM
NA
NA
NA
NA
NA
2
2
2
3
4
4
4
1
60
60
60
PUMP3-5 YR
PUMP 3 YR
PUMP 3-5 YR
EPA, 1986
Otis, 1983
Gunn, 1987
EPA, 1980
Small Flows Clearing House
AVERAGE
RANGE
3
2-4
45.3
1-60
* GPD/CF
** GPD/SF
NA - NOT AVAILABLE
80040000\wp\report.appC
C-1
January 29, 1993
-------
APPENDIX D
EFFICIENCY DATA
-------
EFFECTIVENESS DATA FOR ONSITE SEWAGE DISPOSAL SYSTEMS
REDUCT1
ON IN PO
LLUTANTLOADS
PRACTICE
ST
STUDY
TYPE
WATER
LOAD
GPD
TSS
BOD
COD
TN
TP
PATHO.
WATER
REFERENCE
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
LOG
HI
LOG
LOW
%
HI
%
ANAEROBIC UPFLOW FILT.
ANAEROBIC UPFLOW FILT.
ANAEROBIC UPFLOW FILT.
ANAEROBIC UPFLOW FILT.
ANAEROBIC UPFLOW FILT.
AK
WA
LAB
LAB
IN—SITU
IN-SITU
24
25
30
54
40
89
54
50
46
75
65
84
20
50
60
75
75
75
Venhuizen, 1991
Mitchell, n.A
Venhuizen, 1991
Vcnhuizen, 1991
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDERED
0
44
24 89
6
62
46 84
6
*****
***** *****
0
59
20 75
6
0
0
0
CENT SEPTIC SYS (170 UNIT)
NY
38000
I 85
| 85
1
|
1
1
Orr, 1989
AVERAGE
RANGE
NO. VALUES CONSIDERED
38000
1
85
85 85
1
85
85 85
1
*****
0
0
0
0
0
CONST WETLAND(226d UNIT)
ROCK PLANT FILTERS
CONST WETLAND
MD
MD
IN-SITU
IN-SITU
100000
14000
98
92
50
67
97
96
65
90
90
4
Reed, 1991
Amberg, 1990
Dwyer, et. al. 1989
AVERAGE
RANGE
NO. VALUES CONSIDERED
57000
14K — lOOf
2
80
50 98
3
81
65 97
4
90
90 90
2
4
4 4
1
0
0
0
ELIM. GARBAGE DISPOSAL
ELIM. GARBAGE DISPOSAL
ELIM. GARBAGE DISPOSAL
37
37
37
28
28
5
5
3
2
EPA, 1986
EPA, 1980
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDERED
0
37
37 37
3
28
28 28
2
5
5 5
2
2.5
2 3
2
0
0
0
INT. SAND FILTER
INT. SAND FILTER
INT. SAND FILTER
INT. SAND FILTER
INT. SAND FILTER
INT. SAND FILTER
INT. SAND FILTER
NY
TX
IN-SITU
IN-SITU
LAB
94
70
47
98
90
98
99
96
85
80
91
99
95
92
95
94
93
40
55
60
60
46
75
50
70
90
2
2
4
4
3
4
EPA, 1977
EPA, 1980
Small Flows Gr. H»e.
Venhuizen, 1991
Venhnizen, 1991
Venhuizen, 1991
Venhuizen, 1991
AVERAGE
RANGE
NO. VALUES CONSIDERED
0
92
70 99
7
92
80 99
10
55
40 75
7
80
70 90
2
3.2
2 4
6
0
0
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
TN
WV
WV
IN-SITU
IN-SITU
IN-SITU
10500
200
84
87
93
91
95
98
69
94
80
Venhuizen, 1991
Swanton & Dix, 1988
Venhuizen, 1991
80040000\wp\r9port\appD
D— 1
January 29, 1993
-------
EFFECTIVENESS DATA FOR ONSITE SEWAGE DISPOSAL SYSTEMS
REDUCT
ON IN POLLUTANT LOADS
PRACTICE
ST
STUDY
TYPE
WATER
LOAD
GPD
TSS
BOD
COD
TN
TP
PATHO.
WATER
REFERENCE
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
LOG
HI
LOG
LOW
%
HI
%
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR. SAND FILTER
RECIR SAND FILTER
FL
RI
NY
WV
IL
IN-SITU
IN-SITU
IN-SITU
IN-SITU
IN-SITU
100
70
95
90
90
86
95
98
97
95
91
85
94
90
98
90
75
95
98
95
97
95
1
30
57
50
60
84
80
80
81
70
70
90
2
2
2
3
3
4
3
4
Venhuizen, 1991
Venhuizen, 1991
Lamb et. al., 1988
Laak, 1986
Small Flow* dr. Hje.
Small Flows CIr. Hse.
Small Flows dr. Hse.
EPA, 1980
Sandy «t. al., 1988
Small Flows dr. Hse.
Small Flows dr. Hie.
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDEREE
3600
100-10500
3
90
70 98
12
92
75 98
15
64
1 94
13
80
70 90
2
2.9
2 4
8
0
0
RUCX SYSTEM
RUCK SYSTEM
RUCK SYSTEM
RI
IN-SITU
85
86
70
6
80
50
50
.83
4
Laak, 1986
Lamb «t. al., 1988
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDEREE
0
85
85 85
1
86
86 86
1
51
6 80
5
83
83 83
1
4
4 4
1
0
0
LOW PHOSPHATE DETER.
LOW PHOSPHATE DETER.
50
50
EPA, 1980
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDEREE
0
50
50 50
2
0
0
0
0
0
0
CON V. SEPTIC SYSTEM
CON V. SEPTIC SYSTEM
CON V. SEPTIC SYSTEM
CON V. SEPTIC SYSTEM
CON V. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
WV
RI
RI
VA
CT
NY
W1
RI
CAN
IN-SITU
IN-SITU
[N-SITU
IN-SITU
IN-SITU
IN-SITU
IN-SITU
IN-SITU
100
60
65
70
54
30
60
36
50
19
0
0
45
43
6
42
9
35
40
40
0
60
15
30
90
70
70
29
95
90
90
3
4
EPA, 1480
EPA, 1977
Sandy «t. al., 1988
Lamb et. al., 1988
EPA, 1989
Rhode Island, 1989
Rhode Island, 1989
Rhode Island, 1989
Rhode Island, 1989
Rhode Island, 1989
Rhode Island, 1989
Degen et al., 1991
Healy, 1982
80040000\wp\report\appD
D—2
January 29, 1993
-------
EFFECTIVENESS DATA FOR ONSITE SEWAGE DISPOSAL SYSTEMS
REDUCTION IN POLLUTANT LOADS
PRACTICE
ST
STUDY
TYPE
WATER
LOAD
GPD
TSS
BOD
COD
TN
TP
PATHO.
WATER
REFERENCE
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
%
HI
%
LOW
LOG
HI
LOG
LOW
%
HI
%
CON V. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CON V. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
79
83
78
78
30
58
59
40
45
58
28
Healy, 1982
Healy, 1982
Healy, 1982
Healy, 1982
Healy, 1982
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDERED
80
60—1(X
2
72
54 83
7
45
30 60
7
50
50 50
1
28
0 58
13
57
0 95
12
3.5
3 4
2
0
MOUND SYSTEM
I
1
1
I 44
1
1
1
Degen et al„ 1991
AVERAGE
RANGE
NO. VALUES CONSIDERED
80
60—1(X
0
44
44 44
1
0
0
0
0
0
0
RECYCLE WAST. WATER
LOW FLUSH TOILET
WATER CONS FIX.
HIGHEFF PLUMB.
HIGH EFF PLUMB (TOIL)
HIGH EFF PLUMB.
PA
IN—SITU
36
30
25
4
30
90
90
60
33
31
70
EPA, 1980
Small Flows Or. H»e.
Jarrett et. al., 1985
EPA, 1977
EPA, 1980
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDERED
0
45
4 90
11
0
0
0
0
0
0
WATER SEP. SYSTEM
WATER SEP. SYSTEM
WATER SEP. SYSTEM
WATER SEP. SYSTEM
36
67
61
75
22
49
55
68
78
99
82
90
83
14
20
42
30
40
32
EPA, 1977
EPA, 1986
EPA, 1980
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDERED
0
60
36 75
4
42
22 55
3
0
83
68 99
6
30
14 42
6
***** *****
0
*****
***** *****
0
80040000\wp\report\appD
D—3
January 29, 1993
-------
APPENDIX E
COST DATA
-------
COST (1988S1 DATA FOR ONSITE SEWAGE DISPOSAL SYSTEMS
PRACTICE
ST
CAPITAL COST
CAPITAL COST
O&M COST
O&M COST
REFERENCE
LOW
HIGH
LOW ($/YR>
HIGH ($/YR1
CLUSTER SYSTEM
MI
$3,075
$5,124
Decker, 1987
CLUSTER SYSTEM
NY
$6,900
$370
Small Flows Clr.
House
AVERAGE
$5,033
$370
RANGE
S3,075
$6,900
$370
$370
NO. VALUES CONSIDEREE
3
1
CENT. SEWER SYSTEM
NY
S9,977
$237
Orr, 1989
CONV. TREATMENT SYS.
MI
$8,711
Decker, 1987
CONV. TREATMENT SYS.
VA
$49
$3,926
$86
$294
EPA, 1980
AVERAGE
$5,666
$206
RANGE
$49
$9,977
$86
$294
NO. VALUES CONSIDEREE
4
3
CONS WETLAND*****
AK
$800.00
Reed,1991
CONS WETLAND*****
TN
$1,500.00
Reed, 1991
CONS WETLAND*****
OK
$150.00
Reed,1991
CONS WETLAND*****
AL
$780.00
$905.00
Reed,1991
CONS WETLAND*****
KY
$675.00
Reed,1991
CONS WETLAND*****
LA
$50.00
$215.00
Reed,1991
CONS WETLAND*****
NM
$1,000.00
Reed,1991
CONS WETLAND*****
MA
$230.00
Reed,1991
CONS WETLAND*****
NA
$265.00
$495.00
Reed,1991
CONS WETLAND*****
OR
$90.00
Reed,1991
CONS WETLAND*****
CA
$155.00
Reed,1991
CONS WETLAND * * * * *
MS
$290.00
Reed,1991
CONS WETLAND*****
FL
$375.00
Reed,1991
CONS WETLAND*****
MI
$450.00
Reed,1991
CONS WETLAND (120 SITES)
KY
$1,500.00
$3,500.00
Small Flows Clr.
Hse., 1992
CONS WETLAND
VA
$24.54
EPA, 1980
AVERAGE
$706.58
$24.54
RANGE
$50.00
$3,500.00
$24.54
$24.54
NO. VALUES CONSIDEREE
19
1
HOLDING TANK(2000GAL)
$1,970
$1,200
$2,400
Small Flows Clr.
House
HOLDING TANK(4000GAL)
$4,770
$1,200
$2,400
^mall Flows Clr.
House
HOLDING TANK(5000GAL)
$6,670
$1,200
$2,400
Small Flows Clr.
House
HOLDING TANK(IOOOGAL)
$1,220
$1,200
$2,400
Small Flows Clr.
House
HOLDING TANK(2000GAL)
CO
$4,104
$103
Dix, 1986
HOLDING TANK(4000GAL)
CO
$4,104
$205
pix, 1986
80040000\wp\report\appE
E—1
January 29, 1993
-------
COST (1988S) DATA FOR ONSITE SEWAGE DISPOSAL SYSTEMS
PRACTICE
ST
CAPITAL COST
LOW
CAPITAL COST
HIGH
O&M COST
LOW C$/YR">
O&M COST
HIGH f$/YR1
REFERENCE
HOLDING TANK(8000GAL)
HOLDING TANK
CO
WI
$5,335
$3,422
$205
$850
Dix, 1986
Hanson et. al., 1988
AVERAGE
RANGE
NO. VALUES CONSIDEREE
$3,949
$1,220 $6,670
8
$1,314
$103 $2,400
12
INT. SAND FILTER*
INT. SAND FILTER**
INT. SAND FILTER
INT. SAND FILTER
INT. SAND FILTER
INT. SAND FILTER
NY
NY
$5,000
$2,373
$2,290
$4,408
$6,960
$6,700
$10,000
S25&
$98
$134
$440
$440
Small Flows Clr. House
Small Flows Clr. House
EPA, 1977
Small Flows Clr. House
Small Flows Clr. House
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDERED
$5,390
$2,290 $10,000
7
$274
$98 $440
5
LOW PRESS. SYSTEM
LOW PRESS. SYSTEM
VA
MO
$7,361
$2,833
$147
EPA, 1980
Fulhage & Day, 1988
AVERAGE
RANGE
NO. VALUES CONSIDEREE
$5,097
$2,833 $7,361
2
$147
$147 $147
1
MOUND SYSTEM
MOUND SYSTEM
MOUND SYSTEM
MOUND SYSTEM
MOUND SYSTEM
VA
WI
NY
$11,041
$8,348
$6,800
$7,000
$86
$134
$198
$310
EPA, 1980
EPA, 1977
Hanson et. al., 1988
Small Flows Clr. House
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDEREE
$8,297
$6,800 $11,041
4
$182
$86 $310
4
PACKAGE TREAT. PLANT
VA
I $4,416
I $761
EPA, 1980
AVERAGE
RANGE
NO. VALUES CONSIDEREE
$4,416
$4,416 $4,416
1
$761
$761 $761
1
RECIRC. SAND FILTER
RECIRC. SAND FILTER*«»
RECIRC. SAND FILTER
NY
$1,874
$1,900
$15
$30
$100
$410
Hoxie et. al., 1988
Small Flows Clr. House
Small Flows Clr. House
80040000\wp\report\appE
E—2
January 29,1993
-------
COST (1988$) DATA FOR ONSITE SEWAGE DISPOSAL SYSTEMS
PRACTICE
ST
CAPITAL COST
LOW
CAPITAL COST
HIGH
O&M COST
LOW f$/YR)
O&M COST
HIGH CS/YR1
REFERENCE
RECIRC. SAND FILTER
RECIRC. SAND FILTER
RECIRC. SAND FILTER****
VA
$5,700
$9,201
$2,514
$20
$196
$260
Fulhage & Day, 1988
EPA, 1980
Small Flows Clr. House
AVERAGE
RANGE
NO. VALUES CONSIDERED
$4,238
$1,874 $9,201
5
$147
$15 $410
7
RUCK SYSTEM
NY
$12,311| $16,415
|
Laak,1986
AVERAGE
RANGE
NO. VALUES CONSIDEREE
$14,363
$12,311 $16,415
2
ERR
ERR ERR
0
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
CONV. SEPTIC SYSTEM
WI
CO
VA
MO
$2,000
$4,000
$2,815
$8,207
$3,680
$2,738
$2,500
$10,000
$110
$46
$25
$83
Hanson et. al., 1988
Dix, 1986
EPA, 1980
EPA, 1977
Fulhage & Day, 1988
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDEREE
$4,493
$2,000 $10,000
8
$66
$25 $110
4
ANAEROBIC UPFLOW FIL.
$3,0001 $8,000
1
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDEREE
$5,500
$3,000 $8,000
2
ERR
ERR ERR
0
WATER SEP. SYST.
$5,000| $11,000
| $300
EPA, 1991
AVERAGE
RANGE
NO. VALUES CONSIDEREE
$8,000
$5,000 $11,000
2
$300
$300 $300
1
* Per household cost for a 5000 gpd system assuming 500gpd/household
* * Per household cost for a 30000 gpd system assuming 500gpd/household
*** Per household cost for a 30000 gpd system assuming 500gpd/household
**** Per household cost for a 5000 gpd system assuming 500gpd/household
***** per house hold cost assuming 500gpd/household
80040000\wp\report\appE
E—3
January 29, 1993
------- |