WATER POLLUTION CONTROL RESEARCH SERIES 11050FKE 12/69
A STUDY OF FLOW REDUCTION
AND TREATMENT OF WASTE WATER
FROM HOUSEHOLDS
U.S. DEPARTMENT OF THE INTERIOR FEDERAL. WATER QUALITY ADMINISTRATION
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe the results
and progress in the control and abatement of pollution of our
Nation's waters. They provide a central source of information on
the research, development, and demonstration activities of the
Federal Water Quality Administration, Department of the Interior,
through in-house research and grants and contracts with Federal,
State, and local agencies, research institutions, and industrial
organizations.
Water Pollution Control Research Reports will be distributed to
requesters as supplies permit. Requests should be sent to the
Planning and Resources Office, Office of Research and Development,
Federal Water Quality Administration, Department of the Interior,
Washington, D. C. 20242.
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A STUDY OF FLOW REDUCTION AND TREATMENT
OF WASTE WATER FROM HOUSEHOLDS
by
James R. Bailey
Richard J. Benoit
John L. Dodson
James M. Robb
Harold Wallman
General Dynamics, Electric Boat Division
Groton, Connecticut 06340
for the
FEDERAL WATER QUALITY ADMINISTRATION
DEPARTMENT OF THE INTERIOR
Program #11050 FKE
Contract #14-12-428
FWQA Project Officer, C. L. Swanson
Advanced Waste Treatment Research Laboratory
Cincinnati, Ohio
December, 1969
For sale by tbe Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 - Price $1.25
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FWQA Review Notice
This report has been reviewed by the Federal
Water Quality Administration and approved
for publication. Approval does not signify
that the contents necessarily reflect the
views and policies of the Federal Water
Quality Administration, nor does mention of
trade names or commercial products constitute
endorsement or recommendation for use.
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ABSTRACT
This study was conducted to find practical means of waste flow reduction or waste
treatment for the ordinary household. First, the present water quality and quantity
requirements were reviewed to determine the areas where better water and waste
management would be most beneficial. Much helpful material was gathered from a
review of previous studies on the problems of individual household waste treatment.
More recent information was obtained from manufacturers of plumbing devices and
waste treatment equipment who were surveyed for available water-saving plumbing
devices and individual waste treatment units. Also, the literature on advanced
water and waste treatment was reviewed for processes that might be applicable for
individual home usage.
The information collected was then analyzed to determine the most practical methods
for decreasing the waste volume flow from individual households. Homeowners,
plumbers, architect-engineers, and equipment manufacturers were surveyed to
obtain representative opinions from the people who would control the use of any flow
reduction or treatment schemes. The results of the study and the consumer survey
show that the water used in household functions such as bathing and toilet flushing
can be substantially reduced by the use of more efficient appliances and plumbing
devices. The use of most advanced waste treatment techniques and the reuse of
waste waters is not considered practical except for cases of unusual problems and
extremely high water or waste disposal costs.
This report was submitted in fulfillment of Program #11050 FKE, Contract
#14-12-428, between the Federal Water Quality Administration and General
Dynamics, Electric Boat Division.
ii
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TABLE OF CONTENTS
Section Title .Pag
I INTRODUCTION 1
Background
Present Study
H PRESENT WATER SYSTEM REQUIREMENTS 4
Water Quantity Requirements 4
Water Quality Requirements 8
Quality Standards for Household Uses
Bathing Water Standards 11
General Washing and Cleaning 14
Lawn and Garden Irrigation 17
Toilet Flushing 18
Effluent Quality Requirements for Disposal 20
Effluent Quality for Release to Ground 22
Water
Effluent Quality Criteria for Release 24
to Surface Waters and Storm Sewers
m THE WASTE DISPOSAL PROBLEM OF HOMES NOT 29
CONNECTED TO CENTRAL SEWERAGE SYSTEMS
Background of the Septic Tank Problem 29
Review of Previous Studies 31
Septic Tank Soil Absorption System Research 31
Other Individual Systems 36
Equipment Currently Marketed for Treatment of 40
Waste from Individual Homes
Anaerobic Systems Now Marketed 40
Conventional Septic Tank
A Variation of the Anaerobic System 42
Discussion of Anaerobic Systems 43
Survey of Aerobic Systems 44
Pretreatment 46
Aeration Chamber 46
Solids Separation 46
Final Treatments 46
Economics of Aerobic Treatment Systems 47
Discussion of the Aerobic Treatment Systems 48
iii
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TABLE OF CONTENTS (Cont'd)
Section Title Pag;
Discussion of the Future Demand for Individual 49
Waste Disposal Systems
Present Status of Individual Home Systems 49
Future Projections for Individual Home Systems 49
IV HOUSEHOLD PLUMBING FIXTURES TO REDUCE WATER 52
USAGE REQUIREMENTS
Review of Previous Studies 52
Survey of Plumbing Manufacturers 54
Faucet Flow Reduction Devices 54
Water Closets 55
Urinals 57
Automatic Clothes Washers 57
Automatic Dishwashers 59
Garbage Disposals 59
Cost Estimates 59
Water Savings 61
Cost Evaluation of Plumbing Devices 61
V POSSIBLE TECHNIQUES FOR IMPROVEMENT OF 66
HOUSEHOLD WASTE TREATMENT
Change of Phase Processes 67
Liquid to Vapor Phase Changes 67
Liquid to Solid Phase Changes 69
Solid to Vapor Phase Changes 70
Membrane Processes 70
Reverse Osmosis 71
Electrodialysis 71
Electrolytic Processes 72
Miscellaneous Processes 73
Oxidation 73
Chemical-Mechanical Removal of Contaminants 75
Collection and Storage 76
Solvent Extraction 76
Solid Hydrate Formation 76
77
Maceration-Disinfection ''
iv
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TABLE OF CONTENTS (Cont'd)
Section
VI
vn
vm
APPENDIX
Table A-I
Table A-H
Table A-IH
Table A-IV
Title Page
ENGINEERING STUDY AND EVALUATION OF PROCESSES 78
FOR WATER CONSERVATION AND WASTE TREATMENT
Preliminary Economic Analysis 84
Additional Analysis of Proposed Systems 87
Criteria for a Semi-Quantitative System Evaluation 87
Evaluation Examples 90
SURVEY RESULTS 108
Water Saving Faucets and Showerheads 108
Direct Flush Toilet Valves 110
Toilets with Separate Flush Cycles for Urine 110
and Feces
Home Urinals 110
Recycle Toilets 111
Reuse of Waste Wash Waters 111
Individual Treatment Systems 111
CONCLUSIONS AND RECOMMENDATIONS 112
Conclusions 112
Discussion and General Recommendations 115
REFERENCES 118
ADDITIONAL REFERENCES 127
Waste Treatment Manufacturers 131
Plumbing Equipment Manufacturers 132
Cost Data for Liljendahl Vacuum System 133
Preliminary Cost Comparisons of Alternative Water 135
and Waste Management Systems
Table A-V
Questionnaire Distribution
143
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Section
Table A-VI
Table A-VH
Table A-VIE
Table A-DC
TABLE OF CONTENTS (Cont'd)
Title
Results of the Survey of Homeowners
Results of the Survey of Plumbers
Results of the Survey of Architects and Engineers
Results of the Survey of Plumbing Equipment Manu-
facturers
144
146
149
152
vi
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SUMMARY
PRESENT WATER SYSTEM REQUIREMENTS
The literature on household water quantity requirements was reviewed and an average
household water use pattern postulated. The amount of water used in the various
household functions (bathing, cleaning, toilet Hushing, etc.) is estimated. The water
quantity estimates and the costs associated with using these water quantities are
used as the basis for comparison in the evaluation of all the water-saving or waste
treatment devices.
The various household water uses are then discussed in relation to the quality of the
water required in each use. The quality required is considered from three main points
of view: health, aesthetics, and engineering suitability. Water quality standards are
suggested for bathing, for general laundering and cleaning, toilet flushing, and for
disposal to underground drainage and to surface waters. All uses, except toilet
flushing, require a relatively high level of quality to satisfy the health, aesthetic,
and engineering criteria. The generally high quality requirements tend to discourage
systems with multiple water quality levels. Also, increasing water demands and
water reuse will eventually necessitate very strict disposal requirements.
THE WASTE DISPOSAL PROBLEM OF HOMES NOT CONNECTED TO CENTRAL
SEWERAGE SYSTEMS
The history of the septic tank problem in the United States is briefly outlined and a
review of previous studies on rural and suburban waste disposal problems is
presented. Currently available individual waste disposal systems are surveyed
and evaluated with regard to the information obtained from the review of previous
studies. For most individual waste treatment applications, the anaerobic digestion,
soil absorption type system seems most practical. Waste disposal systems that
discharge effluent to surface drainage are not considered advisable unless fool-
proof safeguards are provided to ensure the effluent quality. Statistics show that
individual waste disposal systems are being installed at a decreasing rate. The
knowledge gained in the many studies on rural and suburban waste disposal systems
and the development of alternative community waste systems have decreased the
tendency to rely solely on individual waste disposal. Also, there appears to be a
trend away from individual housing and toward apartment-type living units. However,
the actual number of individual waste disposal systems being installed and the
number of these systems already in use are very large. These large numbers,
and the rising water quality standards demand better individual waste treatment;
continued study of individual waste treatment systems is essential.
vii
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HOUSEHOLD PLUMBING FIXTURES TO REDUCE WATER USAGE REQUIREMENTS
Previous studies concerning the use of water in plumbing devices and home appliances
were reviewed, and plumbing equipment manufacturers were surveyed to determine
availability of water saving plumbing equipment. Manufacturers, both in this country
and abroad, have developed water saving faucets, showers, and toilets. Because of
water shortages and higher water costs, some foreign countries have placed great
emphasis on conserving water. For example, a vacuum flush toilet has been developed
in Sweden, and in the United Kingdom toilets with two flushing cycles and water-
saving spray faucets are being used. The feasibility of using the various water-
saving devices in the household is evaluated on the basis of cost and water savings.
POSSIBLE TECHNIQUES FOR IMPROVEMENT OF HOUSEHOLD WASTE TREATMENT
The demands for high quality water and the increasing costs of securing and treating
water supplies have stimulated the search for better methods of water and waste
treatment. The literature on advanced treatment methods was surveyed and the
various methods are discussed as to their applicability for household use. Most
of the methods considered do not at this time appear suitable for use in individual
households. However, changes in economic factors and technical improvements
could make some methods attractive for future use.
ENGINEERING STUDY AND EVALUATION OF PROCESSES FOR WATER CONSERVA-
TION AND WASTE TREATMENT
The practicality of using the various schemes of waste treatment or flow reduction
in the household are evaluated. An order-of-magnitude cost analysis of the various
systems led to the following conclusions:
1. Reduction of water usage appears to be the most economically feasible means
of reducing waste flow from the home.
2. Flow control faucets are of marginal value when replacing workable faucets,
but are definitely warranted for new homes and for necessary replacements.
3. Flow control showers are an inexpensive means of economically saving
considerable quantities of water.
4. The use of pressure flush valves to reduce water flow does not appear as
advantageous as the redesign of the toilet bowl to allow adequate flushing
with less water. The pressure flush valve could be advantageously used
with the redesigned toilet bowl. Siphons, as used in the English water
closets, would also provide better volume control than the system presently
used in the United States.
5. The vacuum flush toilet for the individual home is too expensive because
of the high cost of the accompanying equipment.
viii
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6. The major economic disadvantage of the recycle toilets is the high cost of
the chemical used for disinfecting the recycled flush water. Development
of a suitable, lower cost disinfectant could make their use much more
practical. There could be a problem with acceptance of reused flush water
in the home, but this objection does not appear insurmountable.
7. Incinerator toilets are excessively costly to operate and maintain for
family use. For certain applications, such as weekend cabins which are
used sporadically, the incinerator may be the most economical system,
but for normal continuous use, the incinerator toilet cannot economically
compete with conventional systems.
8. The analysis of the system to reuse wash waters for toilet flushing reveals
several very significant facts. The treatment and the quality standards
required for flushing water are minimal and the costs are thus relatively low
in comparison to those for any other reuse. Yet this treatment and reuse
is economical in only fair and poor soil areas.
9. The additional treatment of the non-sanitary waste waters by distillation,
reverse osmosis, or a multifilter system for use as laundry and bathing
water as well as toilet flushing does not appear economically feasible.
10. The treatment of all waste waters by distillation, and reuse for all purposes
except drinking is also economically unattractive.
11. Aerobic treatment is competitive with anaerobic systems in poor soil areas.
In such poor soil areas some reuse may also be warranted.
12. Electrolytic treatment for disposal is not economical for most areas because
of the low conductivity of the water.
Based on these observations, the systems that warrant further consideration are
the various means of restricting water usage, reuse of wash waters for toilet flushing,
and the use of aerobic treatment systems in poor soil areas with the possibility of
treating and reusing portions of the aerobic effluent.
Criteria suitable for a more detailed evaluation were chosen and discussed. Examples,
using these evaluation criteria with several of the water saving and waste treatment
systems, are also presented.
SURVEY RESULTS
A postal survey of homeowners, architect-engineers, plumbers, and plumbing
equipment manufacturers was conducted to obtain representative reactions from the
people who would control the actual use of any schemes for reducing water usage or
improving waste treatment and to ensure that the opinions formed from the literature
survey were not contrary to popular practice or beliefs.
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The response to the survey was relatively good as 387 homeowners, 40 plumbers,
29 architect-engineers, and 8 plumbing equipment manufacturers, representing 50%
of the equipment manufacturers contacted, 52% of the homeowners, 21% of the
architect-engineers, and 18% of the plumbers, filled out and returned the question-
naires.
The survey indicated that water-saving faucets or shower heads and direct-flush
toilet valves are the most acceptable water-saving devices.
Septic tank, soil absorption systems are by far the most common household waste
treatment system. Although 67% of the maintenance schedules reported by the home-
owners were inadequate according to the recommendations of the Public Health
Service "Manual of Septic Tank Practice", most homeowners were pleased with the
performance of their treatment systems.
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INTRODUCTION
BACKGROUND
The practice of water reuse is not new or even recent. The water supply on the
earth is constant and water reuse dates to the beginning of recorded history. Dis-
tillation, membrane processes, and freezing techniques which have occurred naturally
for millions of years are being developed into artificial systems capable of producing
pure, drinkable water from waste waters. Devices are already available to treat
the waste water on space vehicles so that water can be reused. In some water-short
areas, water from the ocean is being economically reclaimed through distillation,
and work is rapidly progressing in the development of freezing techniques and in
membrane technology.
Unfortunately, these processes are only now approaching practical, usable status
for everyday application, whereas water shortages have plagued cities and industries
for centuries. In areas where water has not been plentiful or not easily obtained
various techniques have been developed to permit reuse of water or to relieve
shortages simply by using less water. Some Asian peoples combated water shortages
by an almost complete, though primitive and hygiedcaHy dangerous, reuse of their
meager water supply. The rainfall occurring in the wet season was collected in
open ponds from which water was carried by hand for household use. To conserve
the supply, all cleaning and washing were done in the pond and household wastes
were dumped back into it.
In Chanute, Kansas, during a critical drought in 1956 and 1957, effluent from a
biofiltration plant was diluted with available river water and treated for municipal
use. Sewage provided a considerable portion of the water supply for several months,
but there were no reports of physiological ill effects on the population (17).* Many
industries which have located in water-short areas, for example, Kaiser Steel at
Fontana, California, have found that processing techniques could be designed to
reduce the use of water. Other companies, such as Bethlehem Steel near Baltimore,
Maryland, have solved their own water problems and helped to alleviate pollution
problems by the treatment and reuse of sewage plant effluent. Tourist facilities at
the Grand Canyon have reused effluent from their waste treatment plant for toilet
flushing and for lawn irrigation since 1925. In several coastal areas such as Long
Island, New York, and Southern California, treated waste water is injected into the
groundwater reservoirs to prevent intrusion of salt water as the fresh water table is
lowered by pumping. At Santee, California, and in the Golden Gate Park, San
Francisco, California, extensively treated waste water is being used to irrigate
parks and to supply recreational lakes. In many parts of the world, various schemes
*Numbers in parentheses refer to the list of references, pp. 118-126.
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for reusing treated waste water industrially are already in use; in South Africa
and Israel, reuse for the domestic water supply is also planned.
Implementation of advanced treatment processes and water reuse depend on the
development of better systems for collection of wastes and distribution of the treated
water. Cities will have to be more comprehensively planned so that urban sprawl,
with its disproportionate amount of piping, pumps, and accessories for proper service,
will be controlled. The increasing world population and the fixed supply of water
and fuel make such planning essential for future growth. Water conservation and
the reuse of partially treated water is destined to become increasingly important in
the task of supplying adequate water to the growing world population.
PRESENT STUDY
This study examines the feasibility of applying the principles of water conservation
and reuse of partially treated water to the household, not only to stretch the limited
water supply, but also to provide a transition into the approaching era of complete
water reuse with the corresponding high level of water conservation necessitated by
higher costs of water treatment.
The various uses of water in the typical home are studied in an attempt to find
methods of reusing partially treated water and changing present home practices
which use water needlessly or wastefully. The amount of water that can be poten-
tially saved in a single household may be relatively small, but even small decreases
in the daily per capita water use and waste discharge can result in large cumulative
decreases in costs at the municipal water and sewage treatment plants. Besides
savings in operating costs for water and sewage treatment, the decreased usage
would delay the need for the construction of new waste treatment facilities, for con-
struction of larger sewer lines and water mains, and for the development of new
water supply sources which are becoming increasingly scarce and costly.
This study also examines the special problems of households not connected to
central sewerage systems which must depend on individual treatment units for the
disposal of their wastes. Owners of individual treatment units are faced with the
need for better treatment of wastes to prevent pollution of recreational waters, and
to protect their own or their neighbor's individual water supply. Economical re-
duction of waste discharges would facilitate treatment, decrease pollution, and ease
the demands on an often limited water supply for home owners in areas without
municipal water or sewerage.
This study is divided into six major tasks designed to analyze the need for water
conservation and reuse schemes and to survey and evaluate available techniques of
meeting these needs. These six tasks are listed below:
1. Conduct a study and engineering evaluation of possible changes in household
plumbing fixtures to reduce water usage requirements, and hence reduce
the flow of waste water from households. (Section TV)
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2. Conduct a study of the magnitude of the waste disposal problem from homes
not connected to central sewage systems. (Section HI)
3. Study and evaluate effluent quality criteria (standards) for individual home
treatment systems. (Section n)
4. Survey and evaluate equipment currently marketed for individual home
treatment systems. (Section in)
5. Conduct a comprehensive study and evaluation of treatment processes that
indicate promise for individual home applications. (Sections V, VI)
6. Select the most promising treatment systems for individual home applica-
tion. (Section VIE)
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n
PRESENT WATER SYSTEM REQUIREMENTS
Water's most essential function is sustaining life, but this country fortunately has
such bountiful water supplies that the greatest water use in our modern households
is for removing wastes. We rinse away food wastes from our dishes, the soil from
our homes, our cars, our clothes, and our bodies. We use additional gallons of
water to flush away sanitary wastes.
As the population increases and our water supplies become more critical, it may be
prudent to decrease the amount of water used in essential tasks. This probable need
for changes necessitates an examination of the different household water uses and the
problems associated with changing any of the common practices or the appliances
associated with the present water uses. This section discusses household water
requirements with regard to both quantity and quality.
WATER QUANTITY REQUIREMENTS
Because of the importance of water quantities in the planning of water and waste
treatment facilities, the literature contains many design estimates for the daily
per capita water use. These estimates are usually presented as the quantities needed
for treatment plant design and include leakage into and out of pipes as well as miscell-
aneous non-household uses. Relatively few reports have been published on actual
water usage in individual households and the distribution of the water among the
various uses. One report (reference 65A) from the National Swedish Institute for
Building Research arrived too late to be fully evaluated and included in this study,
but excerpts from several of the tables are included for general information. This
report appears to contain a wealth of information on the quality and quantity of house-
hold waste waters, however the differences between United States and Swedish water
use must be determined before the data can be used directly. Available reports show
that per capita water use varies widely with the standard of living, the climate,
personal habits, and the number of persons per dwelling unit. The actual amount of
water (not including lawn sprinkling) varies from less than 20 to more than 100 gallons
per capita per day (gpcd). The figures most widely reported are between 40 and 80
gpcd. fii a study of 18 homes (97) the average daily water use per person varied from
20 to 70 gallons and averaged 44 gallons. Public Health Service studies to develop
design criteria for soil absorption systems, revealed that the average daily water use
was 56 gallons per person. The Public Health Service study also cited the results
of an extensive water use study in Bethlehem, Pennsylvania which showed the average
use to be 48 gpcd (86). A study at Johns Hopkins University also indicated an average
per person use of 56 gpd (49). Both the study at Johns Hopkins and the study by the
Public Health Service indicated that gpcd water use was inversely proportional to the
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number of persons per dwelling unit. The Public Health Service found that the
statistical average water use (not including lawn sprinkling) fit the formula Q =
88 + 26 P, where Q is the daily gallons of water used per household and P is the
number of persons per household.
The water delivered to the households is divided among the various uses in a
different manner in every household. A few of the published estimates of water use
quantities are listed below.
Household Water Uses (39)
Type of Use
Toilet flush
Bathing
Kitchen
Drinking
Laundry
Cleaning
Sprinkling
Auto washing
Miscellaneous
Estimated Potable Water Use (39)
Type of Use
Drinking, Cooking
Dishwashing
Garbage disposal unit
Laundering, cleaning
Bathing
Total
Percentage
45
30
6
5
4
3
3
1
3
Quantity Used (gpcd)
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Estimated Distribution of Sewage (90)
Waste Volume of Wastet gpcd
Tot. now, (gal.) 30 40 50 75 100
Kitchen wastes 0 7 10 10 15
Toilet wastes 15 15 20 25 30
Showers, wash basins, etc. 15 18 20 25 35
Laundry wastes 0 0 0 15 20
Toilet Flushing (Family of Four) (14)
Water used for toilet flushing
Day of Week % of total daily intake
Monday 44.7
Tuesday 66.9
Wednesday 47.0
Thursday 61.5
Friday 61'9
Saturday 68.5
Sunday 74.4
G. W. Reid (73) published the following estimate for the use of water in the home
of an average family of the future consisting of four members in a house with two
bathrooms, a garbage disposal, a dishwasher and an automatic washer:
Item
Drinking and Kitchen
Dishwasher
Toilet
Bathing
Laundering
Autowashing
Lawn watering
Garbage disposal unit
Total
All uses except toilet and lawn
watering
Daily Family Use, gal.
8
15
96
80
34
10
100
3
346
150
6
Daily per Capita Use, gal,
2.0
3.75
24.0
20.0
8.5
2.5
25.0
0.75
86.5
37.5
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Waste Water Flows (bt>Aj
Source gpcd
Kitchen 13.5
Showers and lavatory 16.4
Laundry 2.3
Toilets 7. (vacuum toilet 5 flushes)
For the purposes of a standard basis throughout this report, the above data and judg-
ment factors were used to fabricate a "model" home with an "average" family which
uses and disposes of water in the "average" way. The home and the values used for
water consumption are believed to be typical of a normal family; however, even if
the values used are not exceedingly close to reality, they will serve as a standard
of comparison to which all schemes for waste treatment or reduction of waste flow
can be compared.
The "average" home used as a standard is a three bedroom structure with 1-1/2
bathrooms, having a shower and tub or a shower-tub combination, and a basement
or storage room where additional equipment could be installed if necessary. The
home has an automatic washing machine and probably a dishwasher and garbage
disposal unit. The "average" family occupying this "average" house will consist
of two adults and two children who will use water in the "average" way.
The use patterns in this "average" home were assumed to be in accordance with
the studies by the Public Health Service and Johns Hopkins University which in-
dicated certain household water using functions are relatively independent of the
number of household occupants. Examples of such functions are laundering, dish-
washing, and cleaning. The amount of water used for cleaning walls, floors, and
fixtures depends primarily on the size of the surface cleaned. Whether done by hand
or by automatic dishwasher, the amount of water used for dishwashing is more
directly related to the number of times dishes are washed than to the amount of dishes
washed. A similar situation occurs with the laundry. White goods, colored goods,
and special materials all have to be laundered separately. For small families this
often means doing a load of washing for a few articles in the amount of water that
would normally be used for a larger load.
In the "model" home, the water for these household uses has been set at 55 gallons
per day: 15 gpd for dishwashing, 35 gpd for laundry, and 5 gpd for miscellaneous
cleaning. The water required for personal uses is set at 50 gallons per day per
person: 3 for drinking and cooking, 20 for bathing, 2 for oral hygiene, and 25 for
toilet flushing. Most of the household water and probably at least 75% of the bathing
water will be heated.
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For the purposes of comparison the following assumptions were made: (1) $0.42
per thousand gallons, (2) an additional cost of $0.67 per thousand gallons of water
heated, and (3) a waste water disposal cost of $0.44 per thousand gallons (municipal
sewerage). The schematic diagram of the "model" home with the corresponding
"average" water uses is shown in Figure 1.
WATER QUALITY REQUIREMENTS
Introduction
This section discusses water criteria and standards: (1) for various household
applications and (2) for disposal to underground drainage or to surface waters.
To significantly reduce total household wastewater flow without relinquishing the
conveniences of modern plumbing and appliances, wastewater treatment and reuse
systems must be considered. However, before treatment requirements for reuse
can be determined, standards of water quality needed for the various household uses
must be established. Although optimum limits of water quality could be established
for each use in a household, simplicity in plumbing and treatment equipment together
with the fact that water from any supply point in a household is used for many things,
dictates that the number of classes of water quality and the corresponding separate
piping systems involved be kept to a minimum.
A new household wastewater system could result in the discharge of a smaller
volume, but a much more concentrated final effluent. For that reason, standards
of effluents for final disposal are also discussed.
Water quality must be considered from three main points of view: health, aesthetics,
and engineering suitability. Table I lists some general aspects to consider in each
category. In household water systems health is of prime importance. However,
health hazards may be eliminated in many cases merely by disinfection.
It has been said that public policy should never compromise on public health issues,
and that the proper philosophy for public water supply planning should not be to
take any available water source and by treatment make it safe for human use, but
rather to take the best supply available and by treatment make it better. Un-
fortunately, the demands of modern life in an industrialized nation seldom permit
so simple and categorical an approach. For example, it is economically and
technically impractical to achieve sterility in public water supplies and human
foodstuffs, but experience has shown that the arbitrary standards of sanitation now
employed reduce public health risks to a minimal level.
Actual health risks are not the only factor, however. Personal habits and current
social customs may affect water conservation and reuse schemes at least as much
as the technical limits required for health considerations and engineering feasibility.
For example, water must have an acceptable appearance and odor even for such low-
level tasks as washing floors.
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255
Potable
Water
Kitchen
27
r
Utility
Sink
5 gpd
Laundry
35 gpd
Bathing
80 gpd
Lavatory
8 gpd
Toilet
100 gpd
255 gpd
to Waste Disposal
dishwashing 15 gpd
.drinking, cooking 12 gpd
Figure 1. Average Household Water Requirements for a Family
of 2 Adults and 2 Children
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Table I. Aspects of Water Quality
1. Health
2. Aesthetic
3. Engineering
Chemical quality
Microbiological quality
Taste
Odor
Appearance (color and turbidity)
Temperature
Chemical Qualities (staining)
Corrosiveness
Hardness
Salinity - Metallic Deposits
Abrasiveness
Settleable Solids
Colloid content
Temperature Bequirements
Volume Requirements
Chemical
Content
Turbidity
10
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Specific quality requirements for various uses are discussed on suosequeni pages.
The following figures and tables show the spectrum of household water uses that
helped dictate the quality requirements specified. Figure 2 shows a schematic of a
typical plumbing system and table II shows the water uses at the various supply points.
Quality Standards for Household Uses
The U. S. Public Health Service has developed water quality standards designed to
insure a product satisfactory for all the uses that commonly occur in the household,
including drinking, cooking, cleaning, home gardening, and use in heating systems
(71). This report uses these water quality standards as the basis of the quality
standards for particular household uses. For all purposes related to drinking and
cooking, these standards must be rigidly maintained; in this study it is assumed that
all drinking and cooking needs will be provided from an acceptable drinking water
supply. For most other purposes, certain of these contaminant limits can be relaxed
without increasing health hazards or decreasing the suitability of the water for the
particular purpose. In all cases, however, the bacterial limits will be maintained
to guard against disease and infection; therefore, only chemical and physical standards
will be discussed in the following sections.
Bathing Water Standards
Substances injurious to the skin should not be allowed to accumulate in water reused
for bathing. For this reason, a pH range is specified for bathing waters. The
range of 6.5 to 8.3 was recommended by the National Technical Advisory Committee
(NTAC) Report (95) for bathing water standards in order to prevent eye irritations.
The physical limits on color and odor should be maintained for aesthetic suitability.
Turbidity limits may be relaxed slightly. Limits on the organic contaminants
detected by the carbon chloroform extract should be adhered to in order to prevent
odor and possible health problems. The chemical limits on cyanide and the heavy
metals listed in section 5.22 of the drinking water standards should be maintained
because of body contact and the possibility of ingestion, especially by small children.
Limits recommended for total dissolved solids in bathing water of 1500 mg/1 are
three times the drinking water standards, but well within the range of useful,
naturally occurring waters. Hardness limits of 100 mg/1, twice the drinking water
standard, are considered reasonable for this use.
Limits on some of the other chemicals can also be somewhat relaxed. The ABS
concentration for drinking water is limited to 0.5 mg/1 to prevent frothing problems,
but frothing is less objectionable in bathing water than in the drinking supply.
Frothing is still very light in concentrations up to 1 mg/1 and this limit is recom-
mended. For drinking, chlorides and sulfates are each limited to 250 mg/1. The
chlorides are limited to prevent a salty taste and the sulfates to prevent a cathartic
reaction in consumers. Since the water is not to be consumed, the limit of either can
be set higher for actual bathing purposes. The requirements of the hot water heating
11
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Potable Vlater Supply
Kitchen
Laundry
Bathroom
Sink*
Garbage grinder
Dishwafeher
Washing Machine*
Set Tub*
Sink* -
Tub*
Shower*.
Toilet bowl
House heating system
Outdoor faucets
A
Floor and other drains
A
*
sewer system or septic tank,
absorption field system
Separate Dry Well ("orbidden by many local codes)
Part of water via hot water heater.
Figure 2. Home Water and Waste Flow Pattern
12
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Table n. Home Water Uses At Various Supply Points
Kitchen
Sink
Drinking
Cooking
Washing - food and equipment
Bathing
Household cleaning
Garbage grinding
Dishwashing - automatic or hand
Laundry
Automatic, Semi-Auto, or Hand
Bathroom (s)
Sink
Drinking
Bathing, toothbrushing
Household cleaning
Toilet - sanitary transport
Shower - Bathing
Bathtub - Bathing
Household cleaning
Occasional Drinking
Heating System
Hot Water Supply
House Heating System (Steam or Hot Water)
Outside Faucet(s)
Lawn and Garden Watering
Car Washing
Pet Washing
Sprinkling Children
Supply to Wading and Swimming Pools
Miscellaneous Cleaning
Occasional Drinking
13
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and piping system, however, limit the combined level to 1500 mg/1. Fluoride
levels could be increased to 3 times the values established for drinking. Copper
and zinc limits can be doubled with no problem other than a bitter taste which would
probably serve a useful purpose by discouraging drinking. Iron levels can also be
raised above the 0.3 mg/1 level recommended to prevent taste. It has been re-
commended that a combined iron and manganese level of 1.0 mg/1 would be sufficient
to prevent staining in laundry applications (54). Maintaining a 0.05 mg/1 limit for
manganese avoids stains and bacterial growth. Nitrate levels as high as 90 mg/1
should be permissible. The limit of 45 mg/1 (as NO ) was set to prevent meth-
emoglobinemia in infants fed on formula made with high nitrate waters, but surely
no infant young enough to be affected by the high nitrate levels would be given the
opportunity to drink even a small amount of bath water, let alone the large quantities
required for toxic effects. Significant concentrations of phenols are unlikely to
appear in household drainage systems, but concentrations in the bathing water of
several times the drinking water limits would cause no problems. The suggested
standards for bathing purposes are shown in table HI.
General Washing and Cleaning - For general household cleaning and laundering,
standards can be further relaxed. The physical standards should still be maintained to
make the water aesthetically acceptable to the housewife. Limits on the solids
concentrations also must be maintained because of the requirements for heating the
water and the fact that water with high dissolved solids will leave deposits on evapora-
tion. The chemical concentration of the other substances can be substantially in-
creased for household cleaning and laundry without increasing the concentrations
above the levels normally found in the water to which cleaning and laundering
solutions have been added.
Some of the substances will of course linger, on cleaned clothes, for example; but
any increase in concentration level will be unnoticeable and non-toxic to children
who occasionally chew on their clothes. Chromium levels of 1.5 mg/1 are re-
commended as permissible for washing and cleaning. Little physiological danger
exists even from quite high chromium levels (54). The taste and odor threshold
level of chromium are 1.4 mg/1, and the possibility of minor coloration or taste
is not deemed unacceptable for this use. Phenol levels of 0.01 mg/1 are 10 times
the USPHS (71) drinking water standards. High taste levels make ingestion of
dangerous quantities of phenols unlikely. Odor thresholds of phenol in chlorinated
water have been reported to range from 0.00001 mg/1 to 0.20 mg/1. The level of
0.01 mg/1 phenol is a reasonable compromise between chance of unpleasant odor and
treatment requirements. Although a pH of 6.0-6.8 is recommended for laundry pur-
poses, (54), attempting to achieve such an ideal is unrealistic for home use; the
wider range of 6. 0 to 8.3 will be acceptable for home laundries. The suggested
quality criteria are listed in table IV.
14
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Table HI. Suggested Bathing Water Standards
Physical Characteristics
Turbidity
Color
Odor
Chemical Characteristics
10 units
15 units
3 units
Alkyl Benzene Sulfonate (ABS)
Arsenic (As)
Barium (Ba)
Cadmium (Cd)
Chloride (Cl)
Chromium (Cr)
Copper (Cu
Carbon Chloroform Extract (CCE)
Cyanide (CN)
Fluoride (F)
Iron (Fe)
Lead (Pb)
Manganese (Mn)
Iron and Manganese
Nitrate (NOJ
O
Phenols
Selenium (Se)
Silver (Ag)
Sulfates (SO )
Total Dissolved Solids (TDS)
Zinc (Zn)
PH
Hardness
Concentration mg/1
1.0
0.05
1.0
0.01
500.0
0.05-
2.0
0.2
0.2
6.0
1.0
0.05
.05
1.0
90.0
0.005
0.01
0.05
500.0
1500.0
10.0
6.5-8.3
100.0
15
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Table IV. Suggested Standards For General Washing and Cleaning
Physical Characteristics Concentration mg/1
Turbidity 10 units
Color 15 units
Odor 3 units
Chemical Characteristics
Alkyl Benzene Sulfonate (ABS) 2.0
Arsenic (As) 0.05
Barium (Ba) 1.0
Cadmium (Cd) 0.01
Chloride (Cl) 500.0
Chromium (Cr) 1.5
Copper (Cu) 2. 0
Carbon Chloroform Extract (CCE) 0.4
Cyanide (CM) 0.2
Fluoride (F) 6.0
Iron (Fe) 1.0
Lead (Pb) 0. 05
Manganese (Mn) .05
Iron and Manganese 1. 0
Nitrate (NO_) 180.0
O
Phenols 0.01
Selenium (Se) 0.01
Silver (Ag) 0.05
Sulfates (SO4) 500.0
Total Dissolved Solids (TDS) 500.0
Zinc (Zn) 10.0
pH 6. 0-8. 3
Hardness 100.0
Alkalinity 60.0
16
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Lawn and Garden Irrigation - Standards for irrigation are less exacting than for
household uses. Untreated sewage has successfully been used for crop irrigation,
and there have been no reports of plant damage by the materials in domestic sewage.
However, the use of untreated sewage on land where human food crops are grown is
not recommended.
There have been reports of typhoid and ascaris worm infection caused by sewage
treated crops, and harmful organisms have been found in vegetables from sewage
irrigated soil. Since all water should be made biologically safe for accidental
ingestion, this should be no problem. The tourist facilities at the Grand Canyon have
used waste water from an activated sludge plant, followed by polishing with anthra-
cite coal filters and chlorination for toilet flushing and lawn watering for more than
thirty years (36).
The use of an individual household effluent for irrigation purposes, however, would
require closer supervision to prevent possible plant damage, since the dilution of
harmful contaminants by the sewage from other homes would not be possible. Boron,
for example, can cause plant damage in very low concentrations. Tolerance ranges run
from 0.5 to 1.0 mg/1 for slight to moderate damage for sensitive crops, 1. 0 to
2.0 mg/1 for semi-tolerant, and 2.0 to 4.0 mg/1 for tolerant crops. As borates
are frequently a constituent in household cleaners, it is conceivable that these con-
centrations could be occasionally exceeded in wastewaters.
The effects of various concentrations of surface active agents in irrigation waters
has not been extensively studied, but, in general, surfactants are not considered
beneficial. Foams may be produced at low concentrations (0.7 mg/1) and may prove
offensive in a sprinkler system. Non-biodegradable detergents could also pollute
ground water if applied to a lawn and garden in sufficient quantities. Limits are
therefore recommended for surfactant substances for lawn irrigation.
Sulfates in high concentrations are reportedly injurious to plants; 200 mg/1 is
recommended as a standard for irrigation waters by McKee and Wolf (54). They
quote a 576 mg/1 limit as permissible, and recommend a 500 mg/1 limit for
domestic water supplies. It is therefore recommended that 500 mg/1 be allowed as
a limit for lawn irrigation and outside faucet uses.
The limit for copper at the 1.0 mg/1 level of the USPHS standards is retained.
McKee and Wolf recommended 0.1 mg/1 for irrigation, but this is a secondary use
for water in a household system and it is not necessary to improve on the basic
water supply for this purpose.
For irrigation a level of 0.5 mg/1 manganese is permissible.
Chloride must also be limited to a level of 500 mg/1 for lawn irrigation. A lower
limit would be better, but this level is not infrequent in some areas. Phenol levels
of up to 50 mg/1 have been found to be acceptable for irrigation (54). However,
17
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at these levels strong odors exist. Considering the multiple uses of domestic lawn
irrigation water, a phenol limit of 0.05 mg/1 is recommended. This level will
create taste in a chlorinated water, but the limit is below the danger level, and taste
will help discourage accidental ingestion. Other compounds, such as nitrates which
have fertilizer properties, could be further increased, but the stipulation of water
not harmful for accidental ingestion suggests limits for these compounds similar to
the values used for wash waters. The suggested standards for irrigation are shown
in table V.
Toilet Flushing - For toilet flushing, the main requirement of the water is to carry
away the wastes. Water is usually the most convenient and economical liquid to use,
but under extreme conditions other fluids have served the purpose; for example,
fuel oil was used to convey wastes in an arctic installation and then burned along
with the waste for fuel. Recently, several attempts have been made to reuse waste
waters for flushing toilets. Stored wastewater from laundry and shower has been
used successfully for toilet flushing with no treatment other than filtration (55).
Detergents caused no foaming problem and the slight gray color was not found
objectionable. As mentioned in the previous section, treated wastewater is used for
toilet flushing at the Grand Canyon. The use of aerobic treatment effluent for toilet
flushing in individual homes was studied at the Ontario Research Foundation in
Canada (15).
Commercial jet aircraft use a recycle system in which recycled waste water (filtered.
colored, and disinfected) is used for flushing. The use of a dye colored water for
this purpose is apparently accepted by the public.
Reasonable criteria for toilet flushing are minimum odor, minimum staining
properties and prevention of serious health hazards. Acceptance of color and
turbidity is dependent on public education. It is probable that housewives in a
community with normal city water would be offended by a reuse system. The reuse
system reported by Mclaughlin (55) was used in the home of the writer, and there-
fore the quality of the water was not questioned as it might have been by an uninvolved
housewife, nor was the system taxed by introduction of unusual substances through
the laundry and shower as it occasionally might be during normal usage.
Levels of 1.0 mg/1 ABS have been reported to cause foaming under favorable
circumstances but concentrations of synthetic detergents were probably higher than
this in Mclaughlin^ system and were reported to be no problem. Of course,
excessive foaming should be avoided.
Manganese, iron, and copper limits may be imposed to prevent staining. In the
studies at the Ontario Research Foundation, this problem was avoided by using a
black toilet bowl which didn't show the stains (12). However, this solution may not
be accepted by the public because of failure to blend with bathroom decor. The
18
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Table V. Suggested Irrigation Water Standards
Physical Characteristics
Turbidity 10 units
Color 15 units
Odor 3 units
Chemical Characteristics Contamination in mg/1
Alkyl Benzene Sulfonate (ABS) 1.0
Arsenic (As) °- °5
Barium (Ba) 1-°
Cadmium (Cd) 0. 01
Chloride (Cl) 500.
Chromium (Cr) °-05
Copper (Cu) 1-0
Carbon Chloroform Extract (CCE) 0.4
Cyanide (CN) 0.2
Fluoride (F) 6- °
Iron (Fe) 1.0
Lead (Pb) °- 05
Manganese (Mn) °«5
Iron and Manganese 1« 0
Nitrate (NOg) 180.0
Phenols °5
Selenium (Se) 0. 01
Silver (Ag) °' °5
Sulfates (SO4) 500.
Total Dissolved Solids (TDS) 1000.
Zinc (Zn) 1°-0
Boron (Bo) 1<0
19
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necessity of treating flushing water to limit staining may impose economic and
physical constraints that would limit the scope of any reuse system. The extent of
this problem would depend on the degree of reuse, the number of use cycles before
disposal, and the concentrations of staining agents.
The desirability of adding disinfectants to the flushing water will depend on the system.
Disinfection was not considered necessary for McLaughlin's wash water reuse system,
but the effectiveness of the detergents and bleaches in reducing bacterial populations
should be investigated. Bacterial counts for the system reusing aerobic treatment
effluent were high, but the addition of disinfectants would disrupt the treatment system.
Therefore in this type of system bacterial kill without a residual effect (heat, radiation,
or ozone for example) will be required.
The sugg2sted standards for toilet flush water are given in table VT.
Effluent Quality Requirements for Disposal
Criteria promulgated by the USPHS (90) specify that human and domestic wastes be
disposed in such a way that:
1. They will not contaminate any drinking water supply.
2. They will not give rise to a public health hazard by being accessible to
insects, rodents, or other possible carriers which may come into contact
with food or drinking water.
3. They will not give rise to a public health hazard by being accessible to
children.
4. They will not violate laws or regulations governing water pollution or
sewage disposal.
5. They will not pollute or contaminate the waters of any bathing beach,
shellfish breeding ground, or stream used for public or domestic water
supply purposes, or for recreational purposes.
6. They will not give rise to a nuisance due to odor or unsightly appearance.
There are, however, no quantitative standards which household effluents, as such,
must meet. Normal, generally acceptable disposal methods now include public
sewerage systems and individual under ground disposal systems. This section
discusses criteria and standards applicable to household effluents for discharge to
ground waters, surface waters, and storm sewers.
Estimates of water used in various household appliances and released to drains
vary widely. Total wastewater volume from three homes studied (97) ranged from
less than 20 to 195 gpd per person. Since wastewater volume varies so widely, the
concentration of specific pollutants will also vary widely. A list of normally
20
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Table VI. Suggested Toilet Flushing Water Standards
A. Physical Characteristics
Turbidity 20 units
Color 30 units
Odor 6 units
B. Tentative Limits of Staining Agents
Mn 0.5 mg/1
Cu 1.0
Fe 1.0
Fe +Mn 1.0
C. Disinfection may be Desirable
21
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occurring potential pollutants found in household drains is given in table VH. Although
typical concentrations of these substances are quite low, actual concentration may
intermittently reach dangerous levels relative to potential reuse with minimal treat-
ment. A system ensuring that all wastewater is subject to a minimum dilution must
be used even when reuse is only for lawn irrigation.
Effluent Quality for Release to Ground Water - The prime basis for the design of
individual underground disposal systems is that they should have a long life without
failure. In practice, failure can be defined simply as refusal of the system to accept
waste, resulting in blocking of plumbing facilities or appearance at the ground surface
of objectionable fluids. Although much work has been done on the design, installa-
tion, and maintenance of septic tank and seepage bed systems to ensure long life
without failure, studies of the state of effluent fluids leaving the immediate seepage
area are sparse, and their results are inconclusive. However, certain standards
of effluent quality are implicit in the codes for underground disposal systems.
Primarily, in the household septic tank system, anaerobic digestion takes place
in the septic tank, and a clarified fluid effluent is released to aerobic percolative
filtration through at least four feet* of the soil absorption system. Accordingly,
after the anaerobic septic tank environment, and the aerobic soil percolation coupled
with mechanical filtration effects, water reaching the ground water table from a
household septic tank and absorption field operating as designed should be pathogen
free, and should contain only minimum amounts of organic substances, ammonia,
etc. Thus, the construction requirements for soil absorption systems (particularly
requirements regarding location with respect to rock ledges and the water table) are
necessary to protect the ground water supply, as well as to insure good operation.
Nitrates, however, which are the normal end products of aerobical.ly digested
nitrogenous organic matter, are not removed from deep ground waters by plant
life. Thus, water percolating from cesspools and leaching fields can cause dangerous
concentrations of nitrates in individual water supplies. Nitrates (the cause of meth-
emoglobinemia) are toxic to infants at concentrations which are harmless to older
children and adults. Nitrate concentrations up to 40 mg/1 have been found at a
distance of 20 feet from a septic tank disposal field (70). Water containing a combined
nitrate plus nitrite level of 45 mg/1 is considered unsafe for the preparation of baby
formulas or other bottle feeds. The septic tank code specifications for distance
between disposal field and water supplies are intended not only to insure adequate
filtration but also to allow for some dilution of wastes not removed.
*This figure (4 feet) is derived from the geometry of absorption fields as
recommended by the Manual for Septic Tank Practice <90).
22
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Table YE. Potential Household Pollutants
KITCHEN
Sink
Dishwashing Debris - detergents, soaps, greases, food and beverage
leftovers, any substance deposited on dishes.
Drain Cleansers
Oven Cleaners
Household Chemicals - Bleaches, ammonia, polishes, floor and
furniture waxes, solvents, ink, insect sprays.
Body Soil and Wastes - Sputum, vomitus, etc.
Any liquid or semi-liquid substances found in household.
Dishwasher - Dishwashing debris.
LAUNDRY
Detergents, bleaches, soaps.
Soil from clothing (may include small amounts of any household substance).
BATHROOM
Sink - All substances listed under kitchen sink except dishwashing debris
Toothpaste, saliva, naso-pharyngeal mucus
Body soil - (anything washed from body)
Tub and Shower - All substances listed under kitchen sink except dishwashing
debris, body soil, urine, occasionally - vomitus, feces
Toilet - Sanitary Waste
Any liquid found in household and solids small enough to be flushed.
23
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ABS and similar refractory synthetic detergents are extremely persistent in ground
water. Their use, however, is decreasing, and biodegradeable substances are
taking their place, reducing the magnitude of this problem.
In summary, explicit standards for wastewaters released to ground waters by
individual underground disposal systems cannot be specified; requirements will differ
in each area. Even the best septic tank soil absorption systems will allow significant
concentrations of nitrates to develop in ground water. However, well designed
systems of sufficient capacity in relation to loading will prevent pathogenic bacteria
and most other contaminants from reaching the ground water table.
Extensive treatment is usually required to enable the water to enter the ground water
reservoir. Deep wells for the injection of renovated municipal waste water are
planned along the south shore of Long Island. These will reduce ground water draw-
down and provide a hydraulic barrier against sea water encroachment. In that area,
27 mgpd of treated wastewater will replace the fresh water now lost in outflow toward
the sea (83, 84). The injected waters will conform to the USPHS drinking water
standards and to other standards to ensure injectability. Degassing and removal of
other constituents which might prevent continued injection will be practiced.
For disposal of wastes to the underground, standards similar to a Pennsylvania
regulation are recommended. This regulation prohibits underground disposal except
in such cases where it can be demonstrated that no conditions prejudicial to the
public interest will result (54). This inherently requires that water reaching ground
water reservoirs must at least meet drinking water standards.
Effluent Quality Criteria for Release to Surface Waters and Storm Sewers - Water
pollution in the past few years has engendered public demand for stricter surface
water standards. Recommendations of various groups, and legislation resulting from
these recommendations, are trending toward controls that preserve and enhance the
quality of water resources. Although there is some argument for the use of surface
waters for waste transport and treatment, this aspect of stream employment is
receiving less favor.
The Suggested State Water Pollution Control Act, Revised (1965), of the Federal
Water Pollution Control Administration, has the provision as a statement of policy
"that no waters be discharged into the waters of the state without first receiving the
necessary treatment or other corrective action ... to provide for the prevention,
abatement and control of new or existing water pollution".
In some states, the standards refer to the effluents before discharge into the
receiving stream. In others, the standards refer to the streams after having
received effluents. In general, at least secondary treatment of wastes (viz.,
chemical, physical or biological treatment in addition to gravity separation of
solids) is required in accordance with federal policy.
24
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Storm sewers, when they discharge into streams, are regulated similarly to other
sources of pollution. Most legal restrictions are directed toward "sanitary sewage and
industrial wastes". An International Joint Commission on Boundary Waters Control,
considering U. S. Canadian boundary waters, included storm waters in their re-
commendations that effluent waters be treated so as to achieve stated conditions in
the open waters. When any sewage waters, even when treated, are discharged into a
storm sewer system, by one line of reasoning the storm sewer becomes a sanitary
sewer, essentially an extension of a sewage treatment plant outfall. Because of
possible health problems associated with sanitary wastes, such discharges of treated
or untreated sanitary sewage to surface waters or storm drains are usually prohibited
by state or local health authorities, except where constant surveilance is provided
by qualified personnel.
Although storm water run-off from urban, suburban, and exurban areas can be as
high in BOD as sewage, these waters are not usually as rich in plant nutrients
(phosphate and nitrogenous species). Eutrophication of receiving waters, especially
impoundments, has become a serious problem, and tertiary treatment for nutrient
removal is often required. Disposal of individual household effluents to surface waters
and storm drainage systems could accelerate the eutrophication of receiving waters.
Non-degradeable polluting substances such as chlorides, metallic and other dissolved
salts, and many toxic, corrosive, colored and taste-producing materials are depen-
dent on dilution for maintenance below acceptable levels. In some streams, these
substances and others such as pharmaceutical and agricultural chemicals, pesticides,
and synthetic detergents are likely to increase in concentration downstream as the
water is reused (33). Broader legislative controls are being recommended in trade
literature and by advisory groups.
The demands for high quality surface waters will significantly affect the disposal of
effluent from individual household treatment systems. In many states, effluents
discharged to surface drainage are the responsibility of state agencies and individual
systems may be forced to meet the same effluent standards as municipal treatment
plants. The demand for assurance of high effluent quality and the possibility of
future demands for removal of nutrients from the effluent could make the surface
disposal of individual treatment system effluents impractical.
An inclusive set of water quality limits for public water supplies was recommended
in the NTAC Report (95). K is not necessarily suggested that the effluents should
meet these standards; however, it is pointed out that multiple stream water reuse
causes almost any effluent now released to surface water to be eventually a constituent
of a public water supply, and these standards may be eventually recommended for
waste-water treatment goals.
Anything short of secondary treatment of effluent for discharge to surface waters
will have to be considered marginal, open to probable criticism, and dependent on
special local conditions, if indeed it will be permitted at all. Planning and engineering
must consider the trend toward tighter control and policies of water resource enhance-
ment.
-------
Conclusions
A summary of the recommended water quality standards is presented in table VHI.
Several final remarks seem pertinent to this discussion. While the concentration
levels of some contaminants may increase several times as standards are
successively relaxed for various purposes, the allowable concentrations of some
substances in each case are still relatively low and continued surveillance is
required to see that the limits are not exceeded. The only reuse for which this is
not extremely important is toilet flushing. Ultimately engineering considerations
will determine if these varying levels of water quality can be practically supplied
to the various supply points, or whether only two or possibly only one level of water
quality is feasible for a household.
For effluent disposal the standards are being raised. The areas where discharges
of less than secondary treatment quality are permitted are decreasing rapidly. In
fact, under the influence of the increasing population the trend is toward demands
that only water of drinking quality can be disposed to ground or surface water
supplies. E is this trend that will eventually make water reuse economically
imperative.
26
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Table VEI. Summary of Recommended Water Quality Standards
(Limits in mg/1)
USPHS
Drinking
Water
Standards
(mandatory
limit)
Turbidity
Color
Odor
ABS
Ag
As
Ba
Bo
Cd
Cl
+6
Cr
Cu
CCE
CN
F
Fe
Pb
Mn
Fe + Mn
N03
Phenols
Se
so4
5
15
3
0.5
0.01
250
1
0.2
0.01
(0. 05)*
(0. 05)
(1.0)
(0. 01)
(0. 05)
(0.2)
(Appendix LA)
0.3
0.5
45
0.001
250
(0. 05)
(0. 01)
General
Washing
Bathing and
Water Cleaning
10
15
3
1.0
0.05
0.01( .05)
(1.0)
0.01
500
0.05
2.0
0.2
0.2
6.0
1.0
0.05
0.05
1
90
0.005
0.01
500
10
15
3
2.0
0.05
0.05
1.0
0.01
500
1.5
2.0
0.4
0.2
6.0
1.0
0.05
0.05
1
180
0.01
0.01
500
Irr.
Waters
10
15
3
1.0
0.05
0.05
1.0
1.0
0.01
500
0.05
1.0
0.4
0.2
6.0
1.0
0.05
0.5
1
180
0.05
0.01
500
Toilet
Flushing
Waters
20
30
6
1.0
1.0
0.5
1.0
27
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Table VIE. (Cont'd)
TDS
Zn
Ph
Hardness
Alkalinity
USPHS
Drinking
Water
Standards
(mandatory
limit)
500
5
Bathing
Water
500
10
6.5-8.3
100
60
General
Washing
and
Cleaning
500
10
6.0-8.3
100
60
Toilet
Irr. Flushing
Waters Waters
1000
10
6.5-8.3
*Numbers in parenthesis are considered the maximum allowable limits
28
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m
THE WASTE DISPOSAL PROBLEM OF HOMES NOT
CONNECTED TO CENTRAL SEWERAGE SYSTEMS
INTRODUCTION
This section discusses (1) the background of the septic tank problem (2) a review
of previous studies on waste disposal for homes not connected to central sewerage
systems, (3) a survey of the individual waste disposal systems presently available
and (4) the magnitude of the individual waste disposal problem, including an
estimation of the present number of homes served by individual waste treatment
systems and a discussion of future trends.
BACKGROUND OF THE SEPTIC TANK PROBLEM
Homes that rely on individual household waste treatment units for waste disposal face
different and more immediate problems than homes connected to a central sewerage
system, since wastes are treated on the homeowner's own lot in his own system.
Malfunctions of the waste disposal system become a problem in his own home, not
somewhere across town at the sewage plant. It is the homeowners own yard that has
unpleasant odors, his own plumbing fixtures that won't function, and his own back-
yard that may be torn up. The many and varied household waste products are not
diluted and combined with the wastes of hundreds or thousands of other homes, but go
directly to the homeowner's own disposal unit and directly affect the treatment
efficiency and the useful life of the treatment system. When the treatment device is
malfunctioning or must be replaced, the homeowner must face the maintenance or
replacement costs himself; it is not a shared community expense. In spite of these
problems, it should be pointed out, that the individual waste disposal system is not
always a source of trouble; in many cases it is the most practical and economical
solution to the waste disposal problem.
The problem of waste disposal from homes not connected to sewerage systems has
largely developed since the late 1930's. The clear differentiation between urban
and rural society had begun to fade as new technology, new demands, and new jobs
began to take effect. Until the development of rural electrification, most rural
homes had lacked not only electrical appliances but also modern plumbing due to
the absence of a pressurized water supply (100). Thus, the rural electrification
program initiated the development of modern rural plumbing and greatly increased
the demand for the septic tank soil absorption system which had first been patented
by John Louis Mouras and Abbe Moigno in 1881 (102).
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These septic tank systems consisted of a tank in which the raw sewage was allowed
to anaerobically decompose before being applied to a subsurface soil bed and were
usually constructed according to local "rules of thumb" or according to construction
guides supplied by the state or federal health departments. In the relatively sparsely
populated rural areas these systems apparently worked satisfactorily as health
officials received very few complaints. However, the paucity of complaints probably
resulted from the relative separation of the systems from populated areas and the
tendency of the owners to personally repair or replace their own sewage systems with-
out reporting the trouble to health officials (100).
Following World War n, the economic and social changes that had begun slowly were
rapidly accelerated. The years of war had left many domestic supplies and appliances
in short supply. This backlog of consumer demand helped to open jobs for the nearly
ten million returning servicemen, who further spurred the consumer demand with
their suddenly increased buying power. Most of these new jobs were in the cities,
and the migration from farms to cities that had begun in the 1800's swelled rapidly,
creating new housing demands in the central cities. Because of the higher wages and
the availability of easy credit through the Federal Housing Administration, much of
this housing demand was for individually financed homes. The percentage of owner
occupied homes rose from about 44% in 1940 to more than 60% in 1960.
Since most of the building sites within the area served by city sewerage systems
were either occupied or priced out of the speculative home building markets, most of
this housing growth occurred on the outskirts of the large cities (24). Also, the enticing
claims that the suburban developments combined all the best features of both city and
country living were partly true. These suburbs were close enough for the convenience
of working, shopping, and enjoying entertainment centers, and far enough to escape
the smoke, dirt, and noise of the industries. This trend to locate in the suburbs
surrounding the central cities was further accelerated by the superhighway systems
which made commuting from the suburbs to the cities much easier. The super-
highway construction itself destroyed city housing and created new demands in the
suburbs (21). Industries and businesses followed this outward expansion and opened
numerous branch offices and local facilities in the developing areas surrounding the
central cities in an effort to escape the rising taxes and growing traffic problems.
Water supply for these developing fringe areas was achieved relatively simply through
private wells or extensions of the municipal water system (100). Sewage disposal
was not as easily supplied, however. Many of these suburbs were well beyond the
economic limits of the central sewage disposal system. Providing city sewerage
service from the central city would have required expensive sewer extensions
with the additional problems of infiltration (7) and probably would have required
the construction of pumping stations since many suburbs were located on marginal
lands topographically unsuited for gravity drainage of sewage. Besides, in most
cities the sewage treatment plants were not prepared to treat the increased volume
of sewage from the subdivisions even if a collection system were provided (87).
Some state laws also favored individual waste disposal systems. In Connecticut, for
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example, the law forbids private institutions to operate sewage treatment plants as
a public utility. Thus, systems that may have been more practical for both builder
and buyer were never considered.
There was no immediate public concern, however, because the septic tank soil
absorption system seemed to offer an adequate solution to the problem. It could
be easily installed by the builder, expenses could be accurately charged to the
home buyer, and it seemed to offer city-type waste disposal at a relatively low cost,
and with little or no maintenance. The soil absorption system was counted on by the
central cities to give adequate treatment to the septic tank effluent right on the home-
owners lot. Health officials, though dubious of this wide-spread adoption of a relatively
untested sewage disposal system, had no real basis on which to forbid septic tank use
(100).
REVIEW OF PREVIOUS STUDIES
Unfortunately, the phenomenal increase in the use of septic tank systems after World
War II did not occur as uneventfully as had been hoped. As large numbers of in-
dividual septic tank systems were put in operation near the cities and relatively
close to neighboring homes, failures were readily noticeable. Due to inadequate
or improperly constructed systems, many of the septic tank soil absorption systems
failed. In some U.S. communities, up to a third of the septic tank systems in the
subdivisions failed within three to four years after installation, thus creating an un-
expected financial burden for the homeowners and bringing the problem to the atten-
tion of the Federal Housing Administration, the principal insurer of housing loans,
and to the attention of the Public Health Service, the principal agency in charge of
sanitary and health problems (53). These organizations initiated a series of exten-
sive studies to explore the mechanisms of waste water disposal in the soil and the
reasons for the eventual failure of the septic tank soil absorption systems. Later
research was designed to investigate other waste treatment systems that might be
better suited for the fringe areas of the large cities. The review of these studies has
been divided into two major groups for the convenience of discussion. These major
headings are: studies on septic tank and soil absorption systems and studies on
other individual treatment systems and alternatives to individual systems.
Septic Tank Soil Absorption System Research
The common concept of a septic tank soil absorption system is a tank in which
to collect and digest sewage solids and a soil absorption system from which the
effluent percolates into the ground (see figure 3). The knowledge of the complex
biological, chemical, and physical processes that occurred in this type sewage
disposal was very limited and there was no good basis for the design of septic tank,
soil absorption systems. The purpose of the initial studies was therefore to
determine the controlling parameters of septic tank, soil absorption systems for
sewage disposal.
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inspection
ports
U
\/////A
inlet
J////1
7
/
- floating scum
- ' ' '--
outlet
Figure 3. Tsrpical Septic Tank Design
-------
The treatment efficiency of the most commonly used septic tank designs was found
not to vary significantly as long as the volumes were comparable. Volume was
found to be the single most important factor of the design of the septic tank. The
volume is very important in allowing adequate settling time, providing capacity for
surge flows as from the bath and laundry, and in providing dilution for possible
chemicals that could upset digestion. Compartmentation further improved perform-
ance by forcing greater utilization of the tank volume (9). More sophisticated designs
could probably be used to improve settling efficiency, but the need for simple
construction and ease of cleaning has kept designs simple.
Later studies investigated the addition of chemicals to the septic tank (through the
water closet) in an attempt to achieve more complete solids removal in the septic
tank (101). Organic and inorganic flocculants were found to achieve significant
solids reductions, but the actual benefit of the addition is questionable. In these,
tests run at the University of California, Sanitary Engineering Research Laboratory,
no overall beneficial effects on the soil absorption system were observed (101).
A major problem connected with the septic tank is maintenance. Not all the material
which settles out of the influent sewage is decomposed. Some of the organic material
and most of the inorganic materials are essentially unaffected by the biological activity
in the septic tank. Therefore, the amount of solid material in the septic tank slowly
increases, and contrary to the popular belief in many areas, no chemical or biological
additives have proven effective in lessening septic tank maintenance (9,40). At some
time, the accumulated solids will attain sufficient bulk to prevent the attainment of
the relatively quiescent conditions which are required for the gravity separation of
suspended solids. Thus, as the volume of accumulated sludge reaches a certain level,
the efficiency of the solids removal decreases markedly and the amount of solids
discharged to the soil absorption system increases. If this solids discharge is
allowed to continue, the system will soon fail. To safeguard the system, the level
of accumulated sludge and scum (floating solids) must be checked often enough to
allow for the timely removal of the accumulated solids. Unfortunately, checking
the level of the solids in the septic tank is not easily accomplished. The earth over
the septic tank must be removed, the top opened, and some type of measuring device
used to physically measure the sludge and scum levels (90). It is time consuming,
odorous, and messy hard work which is understandably postponed even by home-
owners who realize that the septic tank system does require maintenance. Until
trouble erupts, the tendency is to assume that the system is working efficiently.
Probably the most important and expensive, but oddly enough, the most neglected
part of the septic tank, soil absorption system is the soil system. It is in the soil
that the remaining nutrients in the septic tank effluent must be oxidized and the
remaining particles and microorganisms filtered out before the used water reaches
the ground water reservoir. The soil absorption system is the final safeguard of
ground water quality. E is also the quantity limiting factor of the system since
water cannot be discharged through the septic tank faster than it can be absorbed
into the soil absorption system. If the soil cannot absorb the septic tank effluent
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as fast as it is applied, the excess sewage must either back up into the house waste
system or erupt to the surface of the ground. Either case is a serious problem.
Sewage stopped drains and sanitary fixtures are not only inconvenient and odorous
but present a possible health hazard (75). If the sewage breaks through to the ground
surface, there is danger of disease germs being spread with surface drainage,
possibly into drinking water supplies, and collecting in puddles with the likely contact
of children and animals. However, unlike the septic tank which is a physical item
that must be specifically purchased, the soil absorption system appears to simply
convey the liquid waste to the soil through a gravel filled hole. Thus, while builders
have generally accepted the need for larger capacity septic tanks as water usage
has increased, they have been reluctant to increase the size of the soil absorption
field (20).
The studies sponsored by the Public Health Service and the Federal Housing
Administration have attempted to clarify the mechanisms of treatment in the soil
absorption system and the mechanisms by which the soil absorption system becomes
clogged. The ultimate aim of the studies was to obtain sufficient information to allow
recommendations for changes in the design, construction, and operation of soil
absorption systems so that more efficient, safer, and longer lasting service would
be promoted.
The magnitude of the task undertaken is awesome. The soil itself varies from gravel,
through sand and silt, to clay in size, and from pure sand to humus in organic content,
with all manner of variations and combinations between these extremes. The con-
centration, volume, chemical nature, and rate of sewage applied varies with the
geographical location and from household to household. The weather is a very
important factor because it influences ground water level, rate of evaporation, and
to some extent the rates of water usage. To complicate matters, the amount of
sewage applied to the soil is two to ten times as great as normal rainfall and
accepted irrigation rates at which water normally seeps into the soil in nature (9).
As might be expected under these circumstances, the first attempts to systematically
design soil absorption systems were successful only in a limited area. In the 1920fs
Henry Ryon had established an empirical formula to correlate the percolation rate of
pure water to the percolation rate of sewage for some troublesome areas of his
jurisdiction. In an attempt to lend some rationality to the design of their own soil
absorption systems, other public health officials used Ryon's formula or a slightly
modified version of it for design in their own areas. The success of these attempts
was understandably limited.
Other more general design systems were also suggested. These attempted to find
the rate of percolation of water through the soil at equilibrium rather than at initial
conditions (51). However, tests run at the University of California indicate that the
long-term sewage infiltration rate is not significantly related to the initial infiltra-
tion rate for fresh water which is measured by any of the standard percolation tests
(100).
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Researchers soon realized the futility of attempting to analyze the disposal param-
eters prevalent in all the different sections of the country and instead attempted to
first define and explain the fundamental mechanisms of disposal in the soil absorption
system. Studies to determine how soil clogging began and how it progressed revealed
many unexpected facts. Between the very porous coarse sands and gravels, which
almost never clogged, and the almost impervious clay soils, which passed no water
at all, the type of soil seemed to have no great effect on the clogging by septic tank
effluents.
The studies revealed that the percolation of even pure (but not sterilized) water
through this middle range of soils resulted in the reduction of the infiltration rate
to a relatively low percentage of the initial rate. It also became clear that the
infiltration rate, rather than the percolation rate, is the limiting factor. Obviously,
the rate at which water can pass through the lower soil is insignificant if it can't get
through the surface layers (101). The soil surface, or more accurately, the inter-
face between the waste distribution system and the soil, is the key to clogging
problems. Soil grains are consolidated at the surfaces by the passage of even pure
water, and particles in the septic tank effluents are filtered out and collect at this
interface further reducing infiltration rates. At times of high flow the reduced in-
filtration rates cause ponding of the effluent over the soil and promote the anaerobic
conditions which lead to the accumulation of a ferrous sulfide precipitate. The
colloidal ferrous sulfide particles can pass through the surface mat and the insoluble
ferrous sulfide collects in the anaerobic conditions deeper in the soil. This gela-
tinous, black precipitate can soon form an impervious layer completely blocking
further infiltration.
However, even this accumulation would not necessarily ruin the system. Further
research showed that the ferrous sulfide soil blockage was reversible. Under
aerobic conditions, the ferrous sulfide is oxidized to a soluble ferric salt and flushed
through the soil, thus allowing infiltration to continue (100). The aerobic conditions
also relieve the surface clogging as the organic solids are oxidized more rapidly.
Aerobic unsaturated soil is also essential to the removal and oxidation of detergents
and other resistant organic compounds (74). The problem is to obtain and maintain
these aerobic conditions. The most effective technique for achieving these aerobic
conditions was to merely rest the system and apply no more effluents. Unfortunately,
the resting period required to restore infiltration effectiveness is much longer than
now practical, often several months (68).
Other investigations showed that many misconceptions and errors had persisted in
the installation and design of soil absorption systems. Studies showed that the distri-
bution boxes, designed to give equal distribution of septic tank effluent to all parts
of the soil absorption system, were not only unnecessary and theoretically unsound,
but unworkable in practice. Serial distribution was found to be more efficient and also
much less expensive (22). In addition, the researchers found that construction prac-
tices often partially destroyed the infiltration capacity of the soil absorption system
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before it was even put into service. The use of modern excavating equipment has
increased the possibility of smearing and sealing the soil surface so that extra care
must be taken in construction, and in the scheduling of the construction, so that wet
earth conditions conducive to smearing may be avoided (20, 8).
The summation of the experience and knowledge gained through these studies has
been embodied in the 1967 revision of the Public Health Service Publication No. 526,
"Manual of Septic Tank Practice". This manual is well written and serves as an
excellent text and reference for health officials and septic tank installers. It provides
essential information to guide the choice of the system and the design, construction,
and maintenance of the system chosen. It only begins to fulfill the basic need for
educating the users of septic tank systems, however. It is too long and too detailed
to serve the needs of the average homeowner. More brochures such as Public Health
Service Publication No. 73, "Septic Tank Care" (91), are needed and wider distribu-
tion, possibly through septic tank dealers or installers, Health departments, agri-
cultural extension services, etc. is needed. The septic tank installers themselves
have expressed a need for more information on the proper installation and care of
septic tank, soil absorption systems (47).
Another item worth investigating would be the design of septic tanks with unobtrusive
clean-out and inspection ports on the surface. This would eliminate most of the work
in checking the level of floating and settled solids in the tank and promote better
maintenance. Septic tank cleaners have reported that in over half the cases in which
they are called, the owner has acted too late and the soil absorption field has already
been clogged (9).
Other Individual Systems
Even with the best design, construction, and maintenance, septic tank, soil absorp-
tion systems cannot be universally employed. In many areas, the soil is not suitable
for soil absorption type waste disposal. It has been estimated that less than half
the land in the United States is suitable for disposal of waste water and much of the
suitable soil is in the valleys desirable for farming rather than on the high ground
which is desirable for housing (21). In other areas where the soil itself is suitable,
soil absorption systems are undesirable because of high ground water levels such
that adequate filtration cannot be achieved before the effluent enters the ground
water reservoir. This is particularly important since the areas that use individual
waste disposal systems also commonly have individual water supplies and ground
water pollution is a major concern.
In some areas where septic tank systems are widely used, the disposal of the sludge
which must be periodically removed from the tank is a major problem. The open
dumping of these sludges is understandably prohibited near any population centers,
and many municipal treatment plants are unwilling or unable to treat an additional
organic load. Cases such as these emphatically point out the need for extensive,
comprehensive planning before the decisions to permit new housing developments
can be made.
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Just as the streets and power lines in a new area must be carefully planned to
provide the most efficient and most economical service, the method of sewage dis-
posal must be carefully considered. In areas that are sparsely populated and not
likely to grow appreciably, central water distribution and sewage collection systems
may be more costly than the value of the service they could supply. In these areas the
population can be served best by individual systems. In other areas the cost of
individual systems may be greater than the cost of equal or superior service supplied
on a community basis. Before the sewage disposal system can be specified, pre-
liminary projections of future expansion and development of the community is very
important, for the specification of either individual or community systems of waste
disposal could mean a great difference in the cost of sewage disposal service. There
are numerous cases where individual systems have been installed, only to require
replacement with a community system at several times the cost if such a system had
been originally installed, rather than after sidewalks, lawns, and streets have already
been established. Also homeowners who have recently installed or repaired individual
systems usually oppose any movement to establish community service (21). Similarly,
the per household cost of operating and maintaining an improperly designed or
unnecessary community waste disposal system can be prohibitive. Also, in areas
with municipal water supplies where space is available and the soil suitable, individual
systems may not only be more economical but help prevent stream pollution. Pro-
perly designed and maintained individual waste disposal systems in these areas would
probably not burden surface water quality nearly as much as the effluent from a
community waste system providing secondary treatment. The importance of planning
for the overall requirements of a sewage disposal system in the total community
cannot be over emphasized (18).
The choice of waste treatment systems now available is relatively limited. Basically,
the choice is limited to aerobic and anaerobic biological systems. Septic tank, soil
absorption systems are by far the most inexpensive and dependable individual system.
However, they are not suitable in some areas of the country arid other methods must
be used. One modified version of the septic tank system, involving waste separation
and a redesigned soil absorption system, is now being marketed (108).
Individual aerobic treatment systems have been proposed; but while they produce
a higher quality effluent than septic tanks, aerobic treatment presents some of the
same disposal problems and additionally requires maintenance and power not needed
in the septic tank system. The purified liquid effluent from these aerobic treatment
plants still contains organic matter, suspended solids, and possibly pathogenic
bacteria. In most localities, the effluent from these systems must be discharged
to soil absorption systems to provide safe disposal. Even if some means of dis-
infecting the effluent were provided, disposal to surface drainage would be unaccep-
table to many health officials, because malfunctions could occur without notice,
and it would be very expensive for the regulatory agencies to provide the equipment
and personnel needed for even minimum checking of effluent quality. Also many
homes are not located adjacent to streams or water courses into which the treated
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effluent could be discharged. Future developments and new, more reliable systems
of control including service contracts for maintenance and performance checks,
may make these devices more readily acceptable to health officials, but at present,
if they are to enjoy wide usage, they must enable the effluent to be disposed to the
soil more economically than from a septic tank.
The University of California Sanitary Engineering Research Laboratory, conducted
a comparative study of a septic tank system and an aerobic treatment system (100).
The effluents of the two units were very similar with regard to suspended solids and
chemical oxygen demand. The septic tank gave a much more stable performance
and was less subject to upsets. The aerobic unit, on the other hand, gave an
effluent which clogged the soil less severely. Although these tests gave no clear
advantage to either system, it is important to note that the effluent from the septic
tank flowed up through a rock filter which, according to the report, was considered
only to reduce the volume of the second chamber of the septic tank. This filter
probably improved the septic tank effluent measurably.
Studies conducted at the Ohio State University (64) and the Massachusetts Health
Research Institute (19) found that the effluent from aerobic units was superior to
septic tank effluent in suspended solids and BOD. Thomas (87) suggested that with
aerobic treatment units the soil absorption area could be reduced to 1/3 the area
required with septic tanks, In some states the permitted rate for applying aerobic
effluent to soil absorption systems is substantially higher than for septic effluent.
Much recent work has been done to provide sewage disposal systems compatible
with growth areas where continued development is expected, and to develop other
systems suitable for isolated population centers where no further development is
anticipated. In areas where housing development is expected to continue, it is
desirable to install the sewerage system as the homes are built, to avoid the double
cost of temporary individual units and the higher installation costs which prevail
after development has occurred. Such a system must have very low operating costs,
must be expandable, and must fit into the overall plan for sewerage in the area. One
solution would thus be an expandable mobile unit or series of units, in which initial
collection lines would not be too long, and which could be moved and expanded as
population grew. Oxidation or stabilization ponds have begun to receive wider usage
in these situations. One plan of development is to build the stabilization pond in a
convenient location to serve the first homes constructed. When the builder is ready
to construct more homes he simply builds a new pond down stream. The old pond
can be drained and reclaimed for building sites at a relatively low cost (23). In spite
of the attractive low cost features of the stabilization pond, this method is not
completely satisfactory because of the difficulty in controlling and removing algae
growths and the detrimental effect on the effluent. Also, there are advocates of
temporary schemes with higher unit costs which reduce popular resistance to
establishment of a permanent system. Stabilization ponds have been used extensively
in warm regions, but they have also been acceptable in the colder climates (50).
Whatever the type of treatment chosen for the developing areas, the most important
factor is to make sure the initial sewerage scheme is compatible with the overall
long range plan.
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The problem in isolated population centers is somewhat different. The need is for
a permanent treatment system designed to give reliable, low cost treatment. Several
types of treatment have been considered, including package aerobic treatment units,
small anaerobic units, and oxidation ponds. Package aerobic treatment units are
widely used in some areas. Some are merely scaled down versions of a conventional
activated sludge plant, but useful variations of the activated sludge process such as
extended aeration and contact stabilization have also been developed. There are
many reputable manufacturers of package treatment plants, each offering some
special treatment feature for aeration, solids separation, etc., and careful study is
required to choose the type that best meets the requirements of a specific situation.
A problem with many of these systems is the relatively uncontrolled discharge of
aeration tank solids during periods of treatment upset. Stabilization ponds have also
given excellent sewage treatment for permanent installations when they have been
properly designed and are adequately maintained.
Anaerobic treatment systems have been used for sewage treatment for many years.
The Lnhoff tank was used for many years before activated sludge and trickling filters
became popular. Recently, the Public Health Service has investigated the use of an
anaerobic contact process in which the incoming sewage is filtered upward through a
bed of anaerobic sludge (104). Private studies of anaerobic sludge treatment units
are also being conducted (28). The choice of community treatment plants is again
dependent on the circumstances. The number of people served, the money available,
the quality of effluent required, and the maintenance force available will govern the
final selection.
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EQUIPMENT CURRENTLY MARKETED FOR TREATMENT OF WASTE FROM
INDIVIDUAL HOMES
In this section, the devices currently marketed for individual home waste treatment
are evaluated and compared as to first cost (equipment cost and installation expenses),
operating cost, and effluent quality. The evaluation was conducted solely from in-
formation in the literature and from data supplied by the manufacturers; no actual
testing was performed on any of the devices. For convenience in comparing the various
systems, we assumed the treatment devices to be installed at "average" homes
with three bedrooms, four "average" family members, and located on soil with
poor, average, or good (classification according to Thomas (87))permeability. The
discussion of anaerobic devices and aerobic devices is separate.
ANAEROBIC SYSTEMS NOW MARKETED
Conventional Septic Tank
The septic tank is the most commonly used individual waste disposal system. It
consists simply of a container in which wastes are accumulated and digested under
anaerobic conditions. Capacity and hydraulic design are the most important factors
influencing septic tank performance. The capacity is important to allow quiescent
conditions and sufficient time for sedimentation. The capacity must also be sufficient
to dilute chemicals harmful to the digestion process and absorb surge flows from
laundry and bathing without discharging digesting solids. Additional capacity is
required for storage of the digesting solids. The hydraulic design determines storage
efficiency and the extent of short circuiting and thus determines the percentage of
the capacity that is effectively used. Figure 3 showed the principal septic tank
features and figure 4 shows some of the common septic tank designs. The sewage
itself contains the bacteria which catalyze the anaerobic decomposition of the solids
which settle out. The septic tank system has no moving parts and the only main-
tenance required is the removal of solids which resist anaerobic decomposition
and slowly accumulate in the tank. The solids must be removed before the effective
liquid capacity of the tank becomes too small to allow solid particles to effectively
settle out. Empirical formulas have been suggested for the volume of solids in
the tank, but the rate of solids accumulation depends on too many factors (number
of people, type of wastes, design, size of tank, etc.) for such formulations to be
generally applicable. Thus, the time between required cleanings must be determined
by periodic examinations of the solids accumulated. The average period between
cleanings is usually two to four years.
The septic tank is usually constructed of precast concrete or steel, but brick, tile
and other materials are also used. The steel tanks are the least expensive, but
usually have a shorter life expectancy (seven to ten years). Many concrete, tile
and brick tanks, on the other hand, are still operating after more than twenty years
service.
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Figure 4. Common Septic Tank Shape (from Manual of Septic Tank Practice)
41
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Treatment Costs - An adequately sized concrete tank can be obtained for less than
$120; installation of the tank may cost over $250. The effluent from the septic tank
must be discharged to a subsurface soil absorption field for final treatment because
the septic tank effluent is still not fit for surface disposal. The cost of the soil ab-
sorption system cannot be accurately estimated unless the absorption system design,
soil conditions, type of home and labor costs, are known. For purposes of this
discussion we will assume, as mentioned in the introduction, a three-bedroom home
with a four member family and we will theoretically design for a 20-year soil
absorption system life (23) and will use some average cost figures. In a soil with
poor permeability, approximately 1600 square feet of soil interface costing approx-
imately $1600 to $2400 would be required. For a fair soil, only 500 square feet at
$500 to $750 would be needed. In good soils, 170 square feet at $200 to $300 may be
sufficient. Then, with a $14 per year maintenance charge (cleaning every 2 to 4 years),
the yearly cost for waste disposal would be $112 to $152 in poor soils, $57 to $70
in fair soils, and $42 to $47 in good soils. (Basic data from references 87 and 90).
These costs can also be approximately reported as a cost of $1.42 per 1000 gal.
in poor soils, $0.68 per 1000 gal. in fair soils, and $0.47 per 1000 gal. in good
soils.
Effluent Quality - The following table lists a few treatment parameters for the
experimental septic tank used in studies at the Sanitary Engineering Center at the
University of California. Effluent values are compared to the influent sewage values
in terms of mg/1. (Recall that this system had a rock filter which probably in-
creased removal percentages). Aesthetically, the anaerobic effluent may be more
offensive than the raw sewage that enters the tank, because the products of
anaerobic oxidation are commonly odorous compounds. Also, the bacterial content
is often higher than that of the influent sewage.
Septic Tank
Parameter Raw Sewage Effluent % Removal
BOD 150 75 50
COD 310 160 48.4
Suspended Solids 185 50 73
Volatile solids 265 160 39.6
The coliform count of the effluent may be higher than 106 per milliliter, a number
which is 10,000 times the permissible level of 102 organisms per milliliter in the
recommended standards for surface water used for bathing (95).
A Variation of the Anaerobic System
A fiberglass septic tank system now being marketed boasts two significant changes
purported to make it advantageous over the common system. The proper operation
of the system requires that wash waters be separated from sanitary and kitchen
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wastes. The sanitary and kitchen wastes can thus be held in the upper compartment
for a longer period of anaerobic digestion. Under this arrangement, the sanitary
wastes receive more concentrated treatment and the bactericidal effects of some
detergents and household cleaning agents are avoided. The waste wash waters are
conducted to a lower chamber where they are mixed with the effluent from the upper
compartment and undergo a somewhat shorter period of treatment.
This system is sold as a package unit including the soil absorption system which is
designed to be independent of the natural soil characteristics. It is claimed that
sufficient sand and gravel fill is placed around the tank to allow all the effluent to
evaporate to the atmosphere if necessary. Tests reported by the Sanitary Engineering
Research Company (108) indicated that the system can work even in impervious soil.
This system, like normal septic tanks, has no moving parts, and the only main-
tenance required is periodic solids removal. Another feature available with this unit
is a 20-inch inspection and cleaning port which is extendable to the ground surface
and gives access to both compartments.
Treatment Costs - The unit itself costs $445.41 plus shipping costs which will vary
with location. The cost of the piping, installation labor, and the material for the
soil dispersion system would raise the total system cost to approximately $1100.
These systems have been in operation for only a few years and no actual data is
available for estimating maintenance and life expectancy. However, based on the
manufacturer's claims, a soil system and tank life of 20 years with cleaning
required every four years is believed to be reasonable. Thus, an approximate yearly
cost of the system is $65.00. These systems reportedly require the same seepage
area no matter what the soil conditions, so there is no recommended differentiation
for soil conditions. It seems certain, however, that the life of the rock filter
system would increase in good soil locations.
Effluent Quality - This system is designed to produce no effluent to surface waters,
and it is claimed to be operable with no liquid discharge from the rock filter at all.
The testing data in the reports from the Sanitary Engineering Research Company
list only the suspended solids; reported removal of the suspended solids varied
roughly from 50% to 90%, a range not significantly different from the values reported
for the experimental septic tank used by the Sanitary Engineering Research Center
of the University of California, but probably considerably better than the normal
septic tank.
Conclusions - The major advantages of the anaerobic systems are their simplicity
and the resultant low maintenance costs. Of the anaerobic systems considered, the
data indicate that the conventional system is more economical in good to fair soils,
while the new system becomes competitive in fair soils and definitely more
economical in poor soils. Thus the choice depends on the soil conditions. Either
method should be reliable for use. The reliability of the conventional septic tank,
soil absorption system, when well designed and properly maintained, is reflected
by its wide acceptance and use. Such a record is not available for the new system,
but the fact that it has recently been approved by the Federal Housing Administration
testifies to its performance.
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SURVEY OF AEROBIC SYSTEMS
Several types of treatment plants using aerobic, rather than anaerobic, stabilizing
processes to reduce solids and improve effluent quality are now being marketed for
individual home use. The aerobic oxidation system consists essentially of a com-
partmented tank containing an aeration section and a settling section. Most units
are designed for continuous flow, but a few operate on a batch basis to avoid flow
surges in the aeration compartment. In the aeration compartment, the raw sewage
is mixed with the oxygen in the air for relatively long periods of time. Under the
aerobic conditions, the bacteria in the sewage utilize the organic materials for
growth and produce a flocculent bacterial sludge which rapidly absorbs nutrients
from influent sewage. In the settling chamber the bacterial matter is settled leaving
a clarified effluent from which both dissolved and particulate organics have been
removed. Figure 5 shows a typical aerobic treatment unit. Many of the marketed
units include extra treatment processes before and after the basic aeration and
settling sections.
Aerobic treatment systems do not remove unoxidizable and inert waste constituents,
unless provision is made to periodically remove solids from the aeration section or
subsequent treatment step. However, unoxidized and inert solids are not necessarily
discharged from the settling section on an even basis. There is a tendency for solids
to build up to an unstable level, followed by periodic discharge from the system.
The effluent of the aerobic system is generally better than that from an anaerobic
system. Most units claim treatment comparable to municipal secondary treatment
(approximately 90% BOD reduction and 80% reduction of suspended solids). A major
advantage of the aerobic effluent compared to the septic tank effluent is its lesser
clogging effect in soil absorption systems (87). Disadvantages of the system are
higher operating costs, greater susceptibility to shock loadings of concentrated
wastes and to harmful chemicals, and the variations in effluent quality due to such
treatment upsets (100).
In the survey of individual treatment units as many manufacturers as possible were
contacted (the manufacturers supplying information on individual home treatment units
are listed in the appendix (table 1A)). According to one manufacturer, the individual
home treatment market has been in a constant state of flux. He reported that there
had been twenty-five entries into the home waste treatment field since 1955 and that
of these only fourteen were still in business. Eight of these fourteen had entered
the market in the last three years. These figures indicate that there is a great
interest in and a need for an individual treatment system to serve certain areas,
but also that many of the treatment systems marketed have been unacceptable and
probably have created a poor public opinion of the industry.
Most manufacturers were reluctant to release sales figures, but from the data
obtained we estimated that approximately 20 to 30 thousand of the aerobic units
have been installed, primarily by a few of the more reliable manufacturers. The
correspondence and catalogues received from the various manufacturers have been
44
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Inlet
aeration chamber
overflow
weir
J_
outlet
settling
zone
"^^mmmmmm^ sludge return
Figure 5. Basic Design of Aerobic Treatment Units
45
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studied in detail, and the salient design, construction, and treatment features are
discussed below.
Pretreatment
Pretreatment of the sewage is not essential for aerobic treatment, but several of the
manufacturers do provide a pretreatment before aeration. One manufacturer uses a
grinder to reduce the waste material to small particles which are more rapidly
oxidized in the aeration chamber. Another manufacturer uses an anaerobic chamber
in which solids are settled and organics are partially digested before the aeration
chamber is reached.
Aeration Chamber
All the units attempt to mix air with the sewage, but the means of mixing vary
considerably. The greatest number of units installed utilizes mechanical mixers
which physically mix the air with the wastes and at the same time provide continuous
mixing of the liquid. Many of the remaining units blow a fine stream of compressed
air bubbles into the sewage to provide oxygen, and one system uses a vacuum aspirator
system to draw air into the waste fluid which is mixed by the same pump that creates
the vacuum. A Swedish unit (not yet marketed) utilizes a helix in a half cylinder
trough for aeration and agitation. The rough surfaces of the helix pick up a thin
film of waste which is exposed to the air and oxygenated during half of each evolution.
The bacterial scum produced on the surfaces is similar to activated sludge solids.
Solids Separation
There are also many variations in the method of separating the bacterial solids from
the effluent. The most common system is a continuous flow-through tank in which
there is no agitation and the solids settle to the bottom while the clarified liquid flows
out. There is usually a baffle to prevent floating solids from entering the effluent.
The settled solids are usually returned to the aeration chamber by gravity or by a
pump. One system which has been developed and patented but is not currently marketed
provides for completely quiescent settling. Another patented system (not currently
used in individual units though apparently adaptable) uses a slanted tube system in
the settling chamber (27) to provide better settling. Two manufacturers enclose the
aeration section in a bag filter which allows only solids smaller than the filter mesh
to escape from the aeration system. Another unit has a submerged, fixed biological
filter which effluent flows up through following the settling chamber.
Final Treatments
Many of the treatment units come equipped with or have available a variety of post
treatment systems designed to make the effluent more amenable to disposal. The
most common post treatments are disinfection of the effluent and removal of suspended
solids by filtration. Chlorine, ozone, and other chemicals as well as pasteurization
have been suggested for disinfecting the final effluent. One unit relies heavily on
46
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super chlorination to make its effluent acceptable for disposal. In another system,
the effluent is filtered through a particulate and carbon adsorption filter and then re-
used as a toilet flushing liquid.
Economics of Aerobic Treatment Systems
Obviously, the many different aerobic treatment designs vary as to purchase price
installation and operation. However, the systems have sufficient characteristics
in common to allow an approximate table of purchasing and operating costs to be
established. All the systems are designed to provide aerobic oxidation of house-
hold wastes, a process that is time-dependent. Therefore, each system must provide
an aeration chamber in which the sewage is detained long enough for the oxidation
to occur. In most cases, this requirement is simply met by a tank large enough to
provide the required detention. The National Academy of Sciences Report on
"Individual Household Aerobic Sewage Treatment Systems" (60) recommended a
volume in the aeration compartment of 67 gal. per person (no garbage grinder) or
100 gal. per person with a garbage grinder. Since most systems are planned for
at least a six-member family, the volume of the aeration chamber is usually 4 to 6
hundred gallons.
Oxygen requirements can also be treated in general terms. For design purposes,
the raw sewage is generally considered to have some average oxygen consuming value
which requires a certain amount of oxygen. Although the efficiencies of supplying
this oxygen necessarily differ, the variance is probably small in a well-maintained
system. Therefore, it is assumed that, in general, the installation and operating
costs as derived from several of the reliable systems are approximately comparable
for the basic aeration, solids-separation system. The approximate costs of aerobic
systems are listed below. Values are also included for some of the common means of
final treatment.
TREATMENT COSTS
Purchase and Installation Cost $800 to $1600
Operating Costs (per year)
Electricity $ 25 to $ 100
Service and Maintenance $ 30 to $ 50
Filtration
Initial Cost $!50 to $ 200
Yearly Operating Cost $ 10
Disinfection
Initial Cost $!50 to $ 600
Yearly Operating Cost $ 20 to $ 50.
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Using the lower estimated costs without including post treatment costs, the basic
cost of treatment is $95 per year or abour $1. 02 per 1000 gal.; inclusion of filtration
and disinfection would increase this rate to $1. 34 per 1000 gal. Thus except in poor
soil areas aerobic treatment is more costly than anaerobic waste treatment without
even considering disposal of the aerobic effluent.
Discussion of the Aerobic Treatment Systems
A comprehensive review of aerobic treatment systems, including a general review
of treatment unit objectives, general construction and operating criteria, and a
discussion of the conditions wherein aerobic systems should be used, is presented
in the National Academy of Sciences report "Individual Household Aerobic Sewage
Treatment Systems" (60).
High costs are a major problem with the aerobic treatment systems and discharging
the effluent to surface drainage rather than to a subsurface soil absorption system
has been suggested as a means of cost reduction. Some of the treatment units do
consistently produce an effluent suitable for surface drainage. However, other
units obviously have not met acceptable standards and in many areas surface disposal
of aerobic effluent is not legally permitted. The reluctance of public officials to
permit surface disposal is easily understood. Even for treatment units consistently
producing a good effluent it takes only one malfunction to release contaminated water
which could endanger the health of the community. Health officials do not have specific
criteria at this time to evaluate the many different types of treatment units, their
expected performance, or the maintenance problems that might be encountered; and
rather than permit the development of a possible health hazard, a common reaction
has been to prohibit all surface discharges from individual treatment units. Also,
health officials realize that they could not adequately police the number of surface
discharges that could occur. The quality of effluents discharged to storm drains, the
most convenient disposal method, would be even more difficult to monitor.
Sludge disposal is also a problem with aerobic systems. When the extended aeration
system was first proposed it was believed by many that all organic material would be
eventually oxidized to gaseous products and water. However, just as in the septic
tank some organic materials resist digestion, as do nearly all the inorganic solids,
so that there is a gradual build up of solids which must be removed to prevent the
periodic discharge of slugs of sludge particles in the effluent. As with anaerobic
systems the rate of accumulation depends on the system design and operation. Thus
regular inspection is a necessity.
The further growth of the market for individual home aerobic systems thus seems
dependent on the inclusion of adequate safeguards against unattended malfunctions
through better instrumentation, better service contracts, and greater cooperation
among the homeowners, the equipment manufacturers, and the public officials.
The information supplied by the manufacturers indicates that they are attempting to
achieve this goal. No completely satisfactory system has yet been proposed, but
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many advancements have been made and surface discharge is gaining acceptance in
more areas as system improvements and safeguards are supplied.
Each treatment system has features which make it more suitable for certain applica-
tions and each situation will demand a careful examination of specific requirements
before a particular treatment unit can be chosen.
DISCUSSION OF THE FUTURE DEMAND FOR INDIVIDUAL WASTE DISPOSAL SYSTEMS
PRESENT STATUS OF INDIVIDUAL HOME SYSTEMS
The wide-spread growth in the use of the septic tank soil absorption system continued
until today more than twenty-five percent of the 60 million individual housing units
in the country depend on septic tank, soil absorption type sewage disposal. Of the
approximately two hundred million people living in the United States, roughly one
hundred twenty-six million are connected to central sewerage systems, while about
seventy-four million use individual disposal systems (92). Using the national average
of three persons per household, (89) these seventy-four million persons can be
roughly equated to approximately twenty to twenty-five million individual disposal
systems.
The first nationwide data on the numbers and types of household water and waste
disposal systems was collected by the Housing Census of 1960 for communities of
twenty-five thousand or less. These data showed a total of nearly fourteen million
septic tank or cesspool systems. Including the approximately 1.4 million new homes
equipped with septic tanks that have been constructed since 1960 (reports from the
Federal Housing Administration), and allowing for a small percentage of septic tank
installations that are still operating in cities of more than twenty-five thousand people,
the number of septic tank or cesspool installations now in use can be roughly fixed
between fifteen and seventeen million.
A relatively small number of individual aerobic type treatment devices are now in
operation. The total number of these installations is considerably less than fifty
thousand. The five to ten million remaining households use primitive waste disposal
methods or discharge the untreated wastes directly into adjacent water courses.
The number of households reportedly having no plumbing at all, and specifically no
flush toilets, roughly coincides with this number of five to ten million remaining
households. This indicates that most of these homes use a primitive waste disposal
method such as the pit privy.
Future Projections for Individual Home Systems
The population of the United States has increased at a uniformly high rate since the
sudden growth surge following World War H and the demand for housing has increased
correspondingly. However, the actual demand for new homes is primarily a function
of new family formation (21) and the preference of the new family for an apartment
or an individual home. The children born in the high birth rate period of the late
forties are now coming to marriageable age and the rate of new family formation is
49
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rising. At the same time, the percentage of multifamily dwellings is increasing.
Of course, many of the newly formed families have chosen apartment dwelling from
financial necessity, but the number of families who actually prefer apartment living
seems to be increasing. This is partly a result of the growing mobility of our society.
Many families move frequently as jobs change or better opportunities become available
in other cities and other states. The task of repeatedly buying, selling, and main-
taining property becomes very burdensome. Apartments also provide other advantages,
such as recreational facilities which are not available to most homes. Also, modern
apartments are providing the privacy and work space severely lacking in older
apartments. This trend toward permanent apartment living is reflected in the in-
creasing construction of apartments with two or more bedrooms as more families
continue to choose apartment living as their families grow larger. The percentage
of apartments constructed with two or more bedrooms rose from 47% in 1964 to 58%
in 1967 (Economic News Notes, Sept. 1968).
If these trends continue, the demand for individual housing will probably not increase
as rapidly as the population. However, recent trends indicate that most of the
individual homes that are constructed will probably be built beyond the reach of
existing central sewerage systems. Nearly all the recent population gains have taken
place in metropolitan areas as rural population has actually decreased. However,
most of the metropolitan growth has been on the fringes of the cities. From 1950 to
1960,76% of the metropolitan growth was outside the central cities. From 1960 to
1966 this figure increased to 87% (88).
However, the percentage of those new individual homes that will use individual
treatment systems will be difficult to estimate. The knowledge gained in the many
studies on septic tanks and soil absorption systems and the development of alternative
methods of community waste treatment have helped to decrease the rate at which new
septic tank soil absorption systems are being installed. Records of the Federal
Housing Administration show that the percentage of new homes built with septic tank,
soil absorption systems has steadily decreased. In 1960, the percentage of new
individual homes with septic tank, soil absorption type systems was approximately
18 percent. By 1967 the percentage had dropped to approximately 10 percent.
Housing developers and public health officials now recognize that septic tank soil
absorption systems are not suitable for all areas. Also developers are recognizing
the economic advantages of comprehensive planning. It is important to emphasize,
however, that the actual number of septic tank soil absorption systems and other
individual systems being installed is still very large, and will continue to be for some
time in the future. The need for more research on treatment systems for isolated
households and the distribution of the information on individual systems to the
homeowners will increase rather than decrease in the future.
Individual aerobic systems will probably gain a larger share of the home waste
treatment market in the near future as their overall economic superiority over septic
tank systems for certain soil conditions (87) becomes more widely known. Any
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large gains, however, will depend on the development of reliable automatic controls,
fool-proof systems for effluent disinfection, the development of low cost service
contracts, and above all, the confidence of health authorities.
Although the rate of increase of individual systems should decline, the number is
already very high and as water quality requirements become more exacting the prob-
lems of individual treatment will be much greater. Thus, future research cannot be
concentrated only on the types of sewage treatment now commonly used. Other scien-
tific disciplines should be surveyed for possible processes and technology to help
meet the requirements of the future (59). Some of the advanced waste treatment
techniques that are now being tested are reviewed in a later section (section V).
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IV
HOUSEHOLD PLUMBING FIXTURES TO REDUCE
WATER USAGE REQUIREMENTS
INTRODUCTION
This section presents a study and engineering evaluation of possible changes in
household plumbing fixtures to reduce water usage requirements, and hence reduce
the flow of waste water from households (Task I). Specifically, the following program
was undertaken: (a) a review of previous studies, (b) a survey of plumbing fixtures
that have the potential of saving water, and (c) evaluation of the feasibility of using
these fixtures in the household on the basis of quantity of water saved and cost (fixture
cost plus installation labor).
REVIEW OF PREVIOUS STUDIES
The Cornell University study "Bathroom - Criteria for Design" was reviewed (45).
While this report was very interesting, it was slanted more toward physiological,
psychological, and aesthetic improvements in design (i. e., human engineering)
rather than towards a reduction in water usage. For example, the report encourages
the use of the urinal for reasons of convenience and aesthetics, but does not mention
its potential for water savings. Many of the design concepts presented would use
more water rather than less.
Very little information was found in the open literature on water savings to be
realized by the installation of special valves or fittings. In most cases, these
fixtures are designed primarily to conserve hot water and reduce fuel costs. Reduced
hot water use is particularly helpful where the hot water supply is heated instan-
taneously from a house heater.
The British have been very interested in economizing on the use of hot water in
lavatory basins since fuel costs are high in the United Kingdom. In one series of
tests run in large office buildings, wash basins were fitted with thermostatically-
controlled, single outlet spray taps (26, 78). Test results showed one-half to two-
thirds reduction in water consumption for washing as compared to standard basins
fitted with 2 faucets and a drain plug.
The British have developed a dual cycle water closet, one flush cycle for urine, the
other for solid wastes (26, 70). The water closets operate on a syphon system with
a very shallow trap seal. The flush for solid waste is 2.5 gal. (2 Imperial gal.) as
compared with 5 to 6 gal. in the standard American fixture. The urine cycle uses
only 1-1/4 gal. These cycles are actuated by a short sharp stroke or pull for the
smaller amount of water, or a longer sustained pull for solid's flushing (see fig. 6).
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- one gallon* -
, one gallon*
potential saving
A-handle, B-air intake, C-siphon, D-piston
When the piston (D) is held open, the air intake (B)
is closed and the whole contents of the tank are
siphoned.
When the piston is opened, then released, the air
intake is open and the siphon breaks when half the
tank is empty.
* Imperial gal.
Figure 6. Dual Flush Toilet Tank
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The test results using this dual flush cycle in low income flats showed a mean
saving of 27% of the normal water used, (ft should be noted that "normal" for water
closets in England is only 2 Imperial gal. per flush).
These studies have been going on in the United Kingdom since 1956, and the reports
noted above are quite detailed. However, as noted, the tests have been directed
towards large office buildings or multiple family apartments rather than individual
homes.
The reason for this greater concern for water economy in Europe is the higher
water costs and the greater public awareness of these costs. Most services in the
United Kingdom are metered. In the United States, however, public water supplies
in big cities (especially in the older sections) are not metered, and water is wasted
because so much of it seems available at no direct cost to the user.
SURVEY OF PLUMBING FIXTURE MANUFACTURERS
A survey of manufacturers of plumbing fixtures and household appliances was made
to determine the availability (commercial or under development) of hardware devices
that have the potential of reducing water consumption. The companies responding
are listed in Appendix HA. The information furnished leads us to believe that the
manufacturers of plumbing fixtures and equipment are cognizant of the problems
requiring reduction of water consumption and waste water flow reduction in house-
holds. The results of this survey are summarized below.
Faucet Flow Reduction Devices
Several manufacturers currently market limiting flow valves and mixing valves that
restrict the maximum flow rate (29, 67, 46). These valves provide maximum water
savings with showers although they can also be used in kitchen sinks and bathroom
lavatories. One company offers an inexpensive now reduction device which is pres-
sure compensating, fits in the supply lines to faucets or showers and reduces the
flow from conventional fittings.
For shower heads, the flow rate with a limiting flow valve is usually restricted to
about 3 gpm. A water savings (for showers) of 50 to 70% is claimed, but independent
test data are not available. Obviously, the quantity of water saved will be dependent on
many factors, including the water pressure available and the habits of the user.
For lavatory and kitchen sink fittings, the now is usually restricted to 2.5 gpm for
each valve. Water savings are claimed to be "up to 50%", but again test data for
households is not available.
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An important advantage of the flow reduction devices for showers and sinks is the
savings in fuel for hot water heating. A reduction in total hot water consumption of
25 to 40% is claimed; this can provide a reduction in fuel cost that is the same order
of magnitude as the total savings in water cost.
A very simple water-saving device already in wide use is the aerator used on faucets.
Although intended principally as an anti-splash device, it does provide some water
savings. It is estimated that the faucet aerator reduces water consumption at kitchen
and lavatory sinks by approximately 25%.
Another plumbing device which promotes some water savings is the thermostatic
mixing valve, a device which permits mixing of hot and cold water to attain a desired
temperature level. Once adjusted, the proportion of hot and cold water is varied
automatically by a bi-metallic coil as the temperature or pressure of the incoming
water is varied. Thus, the bather is not in danger of being suddenly scalded or
doused with cold water as others in the household stop using or begin using water
at other fixtures. This diminishes the danger of falls as bathers try to avoid the
sudden changes in water temperature while standing on slippery tub or shower
floors. Besides advantages in safety and convenience, the thermostatic mixing
valve offers the opportunity for moderate savings in water consumption. This device
enables the bather to turn the shower off while soaping and to be able to have the
same temperature when the water is turned on for rinsing. This saves the water
that would be wasted as the water temperature is readjusted before rinsing or the
water that would be wasted if the shower were left on in order to avoid the problem
of adjusting the temperature again.
Water Closets
A standard U. S. water closet with a 4 gal. tank will, in most cases, deliver about 5
to 6 gal. of water from the time the handle is tripped to the time the tank refills.
This is considerably more water than is really necessary. U. S. manufacturers now
market shallow-trap toilets that use about one-third less water, i. e., about 3.5
gal./flush (99). One such unit is shown in figure 7.
As noted earlier, the British have pioneered in the use of dual flushing cisterns
(2-1/2 gal. or 1-1/4 gal. /flush). This is now a mandatory requirement in certain
parts of the United Kingdom and has been included in the revision to British Standard
1125 (41). This same reference states:
"With regard to U. K. type closets, you will note that these' are designed
to clear the pans with one 2-gallon flush. There would be no difficulty in
designing a syphon closet, suitable for the American bottom outlet require-
ments, which will also work efficiently with a 2-gallon (Imperial) flush.
We would also mention that in England cisterns are operated by syphons
which prevent the water running away to waste into the W. C. pan. "
55
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Figure 7. Shallow Trap Water Closet
56
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This dual cycle water closet would provide a 70 to 75% reduction in water usage
(as compared to the common U.S. toilet). However, it should be noted that this
design may not meet the requirements of the plumbing codes in some U. S. localities.
Batch-type flush valves (instead of a tank) are widely used in commercial buildings
and apartments, and these could also be used in homes. They can be set to deliver
from 0.5 gal. to 4 gal./cycle (66). However, they would require a larger diameter
water line than is now used to supply a flush tank.
One of the most interesting developments in water closets is the Liljendahl* system
(Swedish) which is being investigated for use in this country by the Eljer Plumbing
Company (103). This system uses air (rather than water) as the transport fluid and
requires only 0.5 gal. water/flush. Plastic pipe (2" dia.) is used for the drain lines,
and a waste receiving tank and vacuum pump are needed. The system is in use in
hotels, motels, apartment houses, and other large buildings in Sweden and in the
Caribbean Islands; it has not , as yet, been used in individual homes. (See figure 8).
Urinals
Wall type urinals of compact design for home installations are available (99). These
urinals have batching-type flush valves set at 1.5 gal. water per use.
The use of urinals in the home would have two obvious disadvantages:
1. additional bathroom space would be required, and
2. the units would serve male household members only.
Female urinals are used on a limited basis in a few office buildings and factories, but
their use in homes is not warranted.
Automatic Clothes Washers
Water requirements for washing machines vary considerably, depending on design,
from about 20 to 33 gal./cycle.
One of the features used with automatic washing machines to save water (and detergent)
has been to store and reuse the wash water. However, this feature has not proved
popular with the consumer as indicated by the following quote (72):
"The automatic washer is but one element in the home laundry process.
Fabrics, detergents and laundry aids have far more effect on water than the
machine does. For some time we have marketed what we call "Suds Miser"
models of our washers. These utilize water twice and at one time represented
a significant share of sales. In recent years homemakers have more or less
rejected the suds saver feature . . . Changes in fabrics and detergent tech-
nology have meant the need for more water. Permanent press items, for in-
stance, require more water for washing because they must go through a gradual
cool down. There is nothing that we, as manufacturers of equipment, can do to
lessen the need for water in the washing process because of developments in
fabrics and laundry aids."
*Mention of a commercial product does not imply endorsement by the Federal Water
Pollution Control Administration.
U I
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timing and water valve
*
main valve
water trap
vacuum
receiving
tank
vacuum pump
(may be located above or below toilet)
Figure 8. Vacuum Toilet System
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Another feature now being marketed is a loading door which acts as a weighing
scale to measure the amount of clothes to be washed. Knowing the weight of the
clothes, the user then selects only the amount of water required to wash a particular
load size. In other words, a water level control is provided which can be set to
avoid using unnecessary extra amounts of water (34).
Another means of reducing the amount of water is by the use of front loader washers.
The washer tub rotates on a horizontal axis and tumbles the clothes through the water.
This type of washer uses approximately half as much water for a particular load size
as compared to the top loading washers and costs about the same. Early homewashers
(patterned after commercial laundry washers) were of this type, but consumer
acceptance was poor.
Automatic Dishwashers
In recent years the number of homes with automatic dishwashers has been increasing
fairly rapidly. Depending on the design, water requirements vary considerably,
i.e., from about 6 gal. to 19 gal./cycle (30). Based on studies that indicated an
average of 1-1/3 uses/day, the average household uses 13 to 19 gal. /day in their
automatic dishwasher (96). These values do not include water used in rinsing the
dishes before putting them in the dishwasher or the water used in washing particular
items. None of the manufacturers contacted indicated any design features specifically
intended to reduce water consumption.
Garbage Disposals
No information on potential water savings for food waste grinders was received from
manufacturers. This is understandable since published information indicates that
total water consumption in the home is not significantly increased by the use of
garbage disposals (16).
Other Fixtures
Except for the devices and features previously described, none of the manufacturers
contacted indicated any plans to market fixtures or appliances designed to reduce
water consumption. If anything, the comments received indicated that water require-
ments for household appliances would increase rather than decrease.
HOUSEHOLD FEASIBILITY OF PLUMBING FIXTURES
Cost Estimates
Cost estimates for each type of water savings device were made for both old con-
struction (remodeling) and for new home construction. For old homes, the purchase
price of the hardware device, as determined from manufacturers' prices, was used.
For new homes the difference in price between the water savings device and the con-
ventional hardware was used.
Installation costs were also estimated for old and new construction. A labor rate
of $7.50/hr was used. Installation material (e. g., piping) was included under
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material costs. Again, for old homes the total installation labor was used, while
for new homes the difference in labor (between the water savings device and
the conventional hardware) was used. The cost estimates are summarized in table
IX.
Costs for the Liljendahl vacuum flush system were estimated by Eljer (103) for
individual homes and for groups of 100 homes. These cost estimates are shown in
Appendix HIA and were used in table IX. This system is not currently being marketed
for use by single homes and would require a waste storage tank (about 50 gal.) and
a vacuum pump for each home. The tank would be discharged periodically into the
main drain line.
The plumbing devices listed in table IX are the following:
1. Shower with limiting flow valves used in place of conventional shower.
Maximum flow rate would be 3.5 gpm.
2. Bathroom lavatory with limiting flow valves (hot and cold water) in place
of conventional faucets.
3. Kitchen sink with limiting flow valves (hot and cold water) in place of con-
ventional faucets.
4. Aerator faucets for bathroom lavatory and kitchen sink.
5. Water closet with one batch-type flush valve (3.5 gal. /flush) in place of
the conventional tank. A 3/4" copper tube water line is used in place of
a 1/2" line.
6. Water closet with two batch-type flush valves (3.5 gal. /flush for solids or
2.5 gal./flush for urine) in place of conventional tank. Again, a 3/4"
water line is used.
7. Urinal with batch-type flow valve (1.5 gal./flush) in addition to conventional
water closet.
8. Water closet with shallow trap (3.5 gal. /flush) in place of conventional water
closet.
9. Dual cycle water closet (2-1/2 gal./flush for solids or 1-1/4 gal./flush
for urine) in place of conventional water closet.
10. Liljendahl-type vacuum flush toilets (0.5 gal./flush) in place of con-
ventional water closet. Drain lines are 2" plastic pipe. A central
collection tank with dual vacuum pumps is used for a group of 100 homes.
11. Same as No. 10 but with tank and vacuum pump for each home.
12. Washing machine with water savings feature such as weighing device and
level control for partial loads.
13. Thermostatic mixing valve used in tub and shower.
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Water Savings
The quantity of water saved by various hardware devices (as compared to a con-
ventional fixture) was estimated. Results are summarized in table DC. The use
of limited flow control valves for showers would give a savings up to 6 gal. /person/
day, or 24 gal./day for a 4 member household. (Item 1). Limiting flow control
valves for the lavatory or kitchen sink result in a relatively small water savings
(Items 2 and 3). Aerator faucets for kitchen and lavatory (assuming no dishwasher)
could give a savings of 2 gal./day for a 4 member household (Item 4).
The use of batch-type flush valves for toilets (rather than tanks) would result in an
average water saving of 1.5 gal./operation. In a household of 4 with 5 uses/day/
person, this would give a savings of 30 gal./day (Item 6).
The use of urinals in the home with a batch-type flush valve, assuming 2 male
members, and 4 uses per male household member would result in a savings of 3.5
gal. per use or 28 gal. /day (Item 8).
The use of the shallow-trap water closet would give a water savings of 7.5 gal./person/
day (Item 9).
A dual flush cycle water closet (British type) would result in a savings of 17.5
gal./person/day or 70 gal./day for a 4 member household (Item 10). The Liljendahl
vacuum flush system would save 23 gal./person/day (Items 11 and 12).
A washing machine with the suds savings feature or with a level control for small
loads could save an estimated 5 gal. /cycle. Based on 6-7 loads/week, water
savings would be about 5 gal./day (Item 13). The savings with the thermostatic
mixing valve would probably amount to less than two gallons per shower which is
equivalent to approximately $1.00 per year per person in water, fuel and sewage
costs. Since thermostatic mixing valves presently cost about $80.00 and installation
would be about $20.00, the thermostatic mixing valve cannot be recommended on
the basis of water savings alone. Selection of this device should be for comfort,
convenience, and safety; water savings are just a side benefit.
Cost Evaluation of Plumbing Devices
In order to evaluate the relative merit of the various plumbing devices presented
in table IX, the following ratios were calculated for each plumbing device:
Total Cost (New Construction)
Water Savings (gpcd)
Obviously, the lower the ratio, the more desirable the plumbing device. Results
are presented in table X (in order of decreasing desirability).
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Table EX. Water Savings vs Cost For Plumbing Devices
Water Savings New Construction Old Construction
Estimated Cost Estimated Cost
Installed Installed
Hardware Device gpcd + gpd* Mail. Cost Matl. Cost
1. Limiting Flow 6 24 15
Valves for
Shower
2. Limiting Flow 0.5 2 25
Valves for
Lavatory
3. Limiting Flow 0.5 2 25
Valves for
Kitchen Sink
4. Aerator for 0.5 2 2
Lavatory and
Kitchen Sink
5. Themostatic 2 8
Mixing Valve
6. Batch-type 7.5 30
Flush Valve
(1) for Water
Closet
7. Batch-type Flush 15.5 62
Valves (2) in
Dual Cycle
8. Urinal with 7 28
Batch-Type
Flush Valve
9. Shallow Trap
Water Closet
10. Dual Cycle
Water Closet
7.5
17.5
30
70
22.5 90
80
25
55
125
20
10
11. Vacuum Flush
Toilet (100
Homes)
+ gal/capita-day (gal/person/day)
* 4 member household
** Negative cost, i. e., cost reduction
15
25
25
70
148
20
10
(110)
**
35
45
45
120
150
80
100
50
68
68
90
40
80
75
100
105
158
175
110
130
295
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Table DC. (Cont'd)
Water Savings New Construction Old Construction
Estimated Cost Estimated Cost
Installed Installed
Hardware Device gpcd + gpd* Matl. Cost Matl. Cost
12. Vacuum Flush 22.5 90 - 1115 - 1520
Toilet (Single
Homes)
13. Washing Machine 1.2 5 35 35 35 35
with Level
Contret
+ gal/capita-day (gal/person/day)
* 4 member household
** Negative cost, i. e., cost reduction
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From these results the following conclusions are drawn:
1. Limiting flow valves appear to be justified for showers and should be
further considered.
2. The vacuum flush water closet can only be justified (economically) for
groups of homes or multi-family dwellings.
3. Of the various water closets and urinals considered, the dual cycle water
closet appears to be the best approach for sanitary waste and should be
further considered.
4. Aerator faucets, where not already in use, should be required.
5. The other plumbing devices listed do not appear to be warranted.
The above conclusions are tentative in that they are based on the cost/water savings
ratio only. Obviously, there are other important considerations, e.g., consumer
acceptability (see section VII). The most desirable plumbing devices are discussed
further in section VI and compared with other alternatives, such as water treatment
and reuse.
Although the available data indicate that the vacuum flush toilet system has many
economic and water conservation advantages, the group application of the vacuum
flush system will not be considered further in this study since our primary concern
is for problem solutions that can be undertaken by individual homeowners. It is,
however, recommended that further studies be conducted and the results made
available to contractors and real estate developers who work with multiple dwelling
unit systems.
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Table X. Cost Evaluation Ratio
_ Total Cost (New Const.)
Water Savings (gpcd)
Kern No. (From
table DO Hardware Device R_
*Negative Cost, i.e. cost reduction
11. Vacuum Flush Toilets (100 Homes) (4.9)*
10. Dual Cycle Water Closet 0.6
4. Aerator Faucets for Sinks 1
1. Limiting Flow Orifice for Shower Head 2.5
9. Shallow Trap Water Closet 2.7
7. Batch-type Flush Valves (2) in Dual Cycle 4.5
6. Batch-type Flush Valve (1) for Water Closet 5.3
8. Urinal with Batch-Type Flush Valve 21
13. Washing Machine with Level Control 29
5. Thermostatic Mixing Valves 45
2. Limiting Flow Valves for Lavatory 50
3. Limiting Flow Valves for Kitchen Sink 50
12. Vacuum Flush Toilet (Single Homes) 50
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POSSIBLE TECHNIQUES FOR IMPROVEMENT
OF HOUSEHOLD WASTE TREATMENT
There was little progress in water and waste treatment technology for thousands of
years. The ancient Egyptians knew the principles of most of our present methods
for purifying drinking water such as filtration, carbon adsorption, exposing to sun
light, and filtration. Although sewage was generally not even treated until after the
middle of the nineteenth century, the water and waste treatment methods most common
today (filtration, sedimentation, disinfection and biological treatment) were all in
practical use by the early 1900's.
Today these methods are no longer sufficient to treat the large quantities and high
concentrations of wastes from our cities and industries. Many locations already
require almost complete waste water renovation to prevent nuisance conditions in
the surrounding waters.
To meet these more stringent treatment demands, additional technology is being
developed and borrowed from other disciplines. The government has initiated many
of the new developments through its own research laboratories and the sponsorship
of private research and development. The government has been instrumental in
many developments through its support of aerospace and ocean exploration programs
which require exacting water and waste management systems and through sponsorship
of research on advanced waste treatment techniques and in the. demineralization of
saline waters.
The marine industry has long been confronted with the problem of limited fresh
water and the disposal of wastes. For years, the practice in all sizes and types of
watercraft was simply to discharge sanitary wastes overboard and depend on the
dilution capacity of the body of water to render the wastes harmless and inoffensive.
Although this practice was acceptable at first when there were very few boats and
relatively little waste matter, the numbers of watercraft have increased rapidly,
especially in the recreational field, and the wastes discharged are no longer
negligible. Also, watercraft waste discharges are usually concentrated in certain
areas and at particular times (summer, weekends, holidays) which usually coincide
with the heaviest water usage for fishing, swimming, and other water contact sports.
The marine industry has attempted various methods for solving this problem. These
methods range from relatively simple methods (closing marine toilets and not using
them, the grinding and disinfection technique, and simple holding tanks) to complex
combination electrochemical treatment devices (38).
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The aerospace industry has also been concerned with water supply and waste disposal,
and the demanding requirements for forced long term isolation have spurred intensive
efforts for the development of self-contained water supply and waste disposal systems.
Water is the heaviest single item required for man's survival (approximately 2500
g. per man per day) and soon becomes a limiting factor unless the water is reused
(76). Thus the very feasibility of space exploration is dependent on water reuse.
Although most of the devices and processes discussed are presently too complicated
and too expensive for the average household, it is believed that a brief presentation
is warranted because this status may be greatly changed in the next ten to twenty
years. The Ontario Research Foundation of Canada conducted a study on the use
of some of these techniques for the complete renovation and reuse of water in a
housing complex for one thousand persons. The technical and economic study indicated
that such a system would be feasible at the present time in water short isolated areas
or areas with very rough terrain (12). The United States Army is developing portable
water and waste management systems utilizing many of these techniques for use in a
mobile field hospital, and for use in advance military headquarters (37, 52). It
must be remembered, however, that in such large housing complexes and in special
service units, skilled personnel should be available at all times, and that the same
economics would not prevail in smaller units. However, continued progress in
instrumentation and automatic control could make some of these processes feasible
for the individual home in the near future.
Applicable advanced treatment processes are discussed briefly below. They are,
for convenience, grouped as change of phase processes, membrane processes,
electrolytic processes, and miscellaneous processes. The processes are first
described and then discussed as to their feasibility for household use. In the
following sections, the feasibility of using these techniques for household treatment,
either as a total process or as a means of improving the effluent from current treat-
ment units (septic tanks and aerobic treatment devices) will be explored.
CHANGE OF PHASE PROCESSES
Liquid to Vapor Phase Changes
In distillation and evaporation processes, the separation of the water from the
impurities is effected by the change of phase from liquid to vapor and back to liquid
again. Only those substances that significantly vaporize at the pressure and tem-
perature of the distillation or evaporation apparatus undergo the same phase changes
and appear as significant pollutants in the product water.
Actually, evaporation and distillation are identical processes but they have slightly
different connotations in practice. In both cases, separation occurs due to the
changes in the relative composition of the liquid and vapor. The rate at which the
liquid enters the vapor phase is dependent on the rate of heat transfer, the rate at
which the vapor is removed, and the relative composition of the liquid phase.
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An air evaporation technique utilizing waste equipment heat has been studied by
several investigators. McNeil (56) investigated an evaporator system to dispose
of urine aboard aircraft, but the product was still corrosive (93). Since then, other
investigators have reported a considerably better product which could be rendered
potable by varying degrees of auxiliary treatment with chemicals, ion exchange,
and activated carbon (76, 69). In a 60-day manned test of a closed life support
system an air evaporation unit successfully reclaimed water from urine and humidity
condensate for a crew of four men (43). For aerospace applications, the major dis-
advantages of the air evaporation system are the large surface areas (3.5 sq.
ft. per man reported by Wallman and Barnett (93) required for sufficient heat
transfer and the storage and disposal of the wicks used to provide these large
surface areas.
For the household use of an air evaporation system, the problems of weight and
storage space which were considered limiting for aerospace applications do not
seem to be as significant. However, it must be remembered that the systems
considered for aerospace use were designed to process less than one gallon per
man per day, whereas we are contemplating a use of more than sixty gallons per
person each day. Also, one of the major advantages of the system for spacecraft,
the use of waste cabin and equipment heat which would otherwise be expelled to
space, is not possible in most homes. Thus in the normal household, rather than
3. 5 square feet of wick area per person, approximately 220 square feet would be
required and power would be used at the rate of 338 watt-hours per pound of water
produced ($56.50 per 1000 gal.) (69). The water evaporated from raw wastes could
be easily disposed of, but would require further treatment (e. g. filtration, adsorption,
sterilization) before any reuse because of possible microbial contamination and pro-
bably odors. A household system would additionally require a collection tank, a
blower, and heating and condensing equipment.
The wastes from this process should be solid and easily handled though they would
probably have a disagreeable odor.
Distillation can be carried out at various interdependent temperature and pressure
combinations depending on the product desired. Generally, low pressures are
utilized to permit low temperatures and limit the decomposition and volatilization of
organics. In some units, the vapor is compressed without cooling so that the heat of
vaporization can be more easily utilized in the distillation unit (vapor compression
distillation). As with air evaporation, however, the product water still requires
additional treatment before it is judged potable. Membrane vapor diffusion is another
distillation process in which a semi-permeable membrane is used to contain and
separate the impure liquid from the vapor phase. The heated liquid diffuses through
the membrane and evaporates on the outer surface. An important advantage with
this system for aerospace use is its operability at zero gravity. With further mem-
brane improvements, the membrane vapor diffusion system should be competitive
with vapor compression (48). One method of additional treatment is to catalytically
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oxidize the vapor before it is condensed (6, 32). The major disadvantages of the
distillation schemes for aerospace use are the high power and weight require-
ments (relatively speaking) and the danger of gas leaks in systems that operate
at other than ambient pressure (82).
A household system for distillation would require a collection tank, a solids
separator (possibly included in the storage tank), and probably a final filtration,
adsorption unit which would render the effluent suitable for all uses except drinking.
A vapor compression distillation system which conserves the heat of vaporization
required 35.3 watt hours per pound of water produced, (69) or $5.90 per thousand
gallons of water. Steele (82) reported a power expenditure of 42.8 watt hours per
pound or $7.15 per thousand gallons. Studies on a vapor compression unit designed
for household use by Dr. Hickman of Rochester Institute of Technology reported
operating costs of about $1.30 to $2. 00 per thousand gallons (10). The yield from
this unit which is limited to dilute wastes, is only about 1/3 to 1/2 the input. Operation
of a distillation unit would depend on the close control of a number of variables and
would probably present household problems. The waste from a distillation system
would be a dry sterile residue which could be easily handled or a concentrated
liquid. There would also be the problem of disposing of the solids separated from
the waste water in the initial treatment step. These could probably be treated
similarly to septic tank solids.
Liquid-to-Solid Phase Changes
Pure water freezes at a higher temperature than a mixture of water and wastes.
Thus when the water-waste mixture is slowly cooled, pure crystals of water form.
The problem is to separate the crystals of pure water from the waste mixture
entrapped in the crystal interstices. Various techniques to obtain this separation are
being investigated. Multi-stage counter-current washing has been effective in
large scale operations, but at present, the technique appears uneconomical for
aerospace application (106, 82). Zone refining is another variation of the freezing
process in which a column of water, waste mixture is frozen; then a moveable
heating element forms a band of liquid which is moved along the column concentrating
impurities in the liquid phase (76). The process may be repeated for increased
purification. Other freezing processes that have not been significantly developed
are column crystallization and counter current crystallization (82). The major
objections to these techniques are the low percentage of water recovered and the
problems of separating the ice from the water-waste mixture.
In addition to cooling equipment the processes involving solid liquid separation
will require elaborate separation equipment. Work with freezing techniques involving
liquid solid separation for waste water renovation has been relatively unsuccessful
due to the difficulty of separating the pure ice from the waste water. Studies at the
Robert A. Taft Sanitary Water Research Center on freezing techniques for the
renovation of waste water were halted because of the relatively high process costs.
Besides the high costs, the freezing techniques require constant control and super-
vision to insure quality. Most homes could not supply this supervision.
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Solid-to-Vapor Phase Changes
At low temperatures and pressures, water can be changed directly from a solid to
a vapor without passing through the liquid phase. This sublimation or freeze
drying process is rapidly becoming an important food preservation process. The
low temperatures limit organic decomposition and volatilization to insure a relatively
high quality product. Virtually all the water is recoverable, and the waste materials
remain in the solid state, thus facilitating waste handling and reducing leakage pro-
blems (82).
The processes involving vapor sublimation from the solid ice will require vacuum
apparatus and vapor condensing equipment.
The system involving the solid to vapor phase change has demonstrated the capability
of producing a good quality water. Energy equal to the energy difference between the
solid and liquid must be removed from the waste water to produce ice, and then just
enough energy must be added to change the solid to a vapor from which the water is
then condensed. The household cost of these processes is estimated to be at least
(assuming 80% power recovery) $10.90 per thousand gal. and would yield water
suitable for any use but drinking.
The waste residues from the process could be easily handled and stored until cen-
trally collected.
MEMBRANE PROCESSES
Membrane processes require no phase change; they depend on membrane selectivity
to separate the water from the wastes. The membrane acts as a filter to exclude
all particles larger than its pores, and as a diffusion medium which governs the rate
at which soluble substances pass through it. By altering the structure and com-
position of the membrane the substances passed by the membrane can be selectively
controlled. The membrane mechanically restricts the passage of any substance and
a force is necessary to drive a substance through the membrane. Additional energy
is required to overcome the concentration dependent osmotic pressure. Mechanical,
electrical, thermal, and concentration gradients have been successfully used as the
driving force in various applications. One major problem with the membrane
purification process is that the practical limit to which the wastes can be concentrated
is much lower than the concentration at which the wastes can be easily handled and
disposed of. However, membrane processes theoretically require less energy than
the phase change processes, and much water treatment research is directed toward
solving or by-passing the problem areas of membrane technology. Spectacular
results are also being predicted for the application of membranes in many different
fields: medical technology (artificial organs), photographic equipment, batteries,
etc. (57). The concentrated efforts in these varied fields could hasten the discovery
of solutions to membrane problems.
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Reverse Osmosis
Originally, ultrafiltration was used to denote microstraining and reverse osmosis
was used for the process utilizing activated diffusion. Ultrafiltration membranes are
rapidly clogged, however, and there is a tendency to use reverse osmosis membranes
for ultrafiltration. As a result, the two terms are sometimes used interchangeably
to describe the forced solvent flow through a membrane from a high solute concentra-
tion to a low concentration in opposition to the natural concentration gradient. Con-
siderable research is being conducted to perfect reverse osmosis techniques for
industrial processing and for treatment of various industrial and municipal waste
streams (65).
Although reverse osmosis has the capability of removing non-ionic material as well
as ionic species, probably its first household usage will be for the removal of ionic
species. A household unit for demineralizing water and which operates on the water
line pressure has already been developed and is projected to be sold for approxi-
mately $125 and to treat the water at a cost of about $8.20 per thousand gallons
(63). One manufacturer has begun promotion of its version of a small reverse
osmosis system to remove taste, odor, color and sediment. Costs are estimated
at seven cents per gallon ($70. 00 per 1000 gal. >. The cost of treating more con-
centrated wastes would be significantly higher because of the higher osmotic pres-
sure of the wastes and the additional equipment that would be required. The wastes
from a reverse osmosis treatment unit would be a concentrated liquid with pro-
perties dependent on the wastes being processed. The product water could be used
for all household purposes except drinking.
Electrodialysis
Electrodialysis is a membrane technique in which the driving force is electrical
potential. Membranes can be prepared to pass only cations or anions, and a solution
placed between an anion permeable membrane and a cation permeable membrane
and subjected to an electrical potential can be effectively depleted of ionic solutes.
However, nonionic species are not affected. The main disadvantages of electro-
dialysis are the additional purification processes that must be used to remove
uncharged particles and particles too large to pass through the membrane (81). A
variation of electrodialysis, the osmionic process, utilizes ion permeable membranes
to produce electricity for electrodialysis. Ions flow from a concentrated salt
solution to dilute solutions through cation and anion selective membranes, creating
an electrical potential between the dilute solutions which is then used for
conventional electrodialysis. This process requires large quantities of the salt
solutions, and like electrodialysis produces dilute wastes, and a product that still
requires additional treatment (83, 11).
Thermo-osmosis utilizes a temperature gradient to drive the water through the
membrane. When solutions of different temperatures are placed on opposite sides of
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a semi-permeable membrane, there is usually some transport of water from one
solution to the other. The rate of water transport is determined by the temperature
difference and the thermal characteristics of the membrane itself (93).
Electrodialysis or related techniques could only be a part of a water treatment scheme
since they remove only ionic species. The power required for such a system is a
function of the quantity of ions in solution. The cost of power has been estimated
at $8.50 per thousand gallons for the electrodialysis of treated urine and at approx-
imately $1.00 per thousand gallons (extrapolation of data by Smith, (77) for the
effluent of a secondary treatment plant. The wastes to be disposed of will be con-
centrated salt solutions.
ELECTROLYTIC PROCESSES
Electrolytic waste treatment plants attracted a great deal of interest in the late
1800's and early 1900's. The most famous process was the Landreth method in
which the waste water was heavily dosed with lime and then subjected a direct
electrical current. The effluent was described as clear, odorless and non-putrescent.
There was some question as to whether the same degree of treatment could be ob-
tained with the concentrated lime dosage alone (58).
The Pennsalt Chemical Corporation, under contract to the Public Health Service,
completed an extensive study of electrochemical treatment of secondary treatment
effluent. This study concluded that the system was uneconomical (a cost in a 10
mgd plant of $. 90 to 2.40 per 1000 gal.) because of the low conductivity of the
water.
The electrolytic process is being investigated for treatment of raw sewage by
chemical coagulation of suspended solid material and chemical treatment of the
liquid in Norway and Italy. The sewage and sea water are mixed and electrolyti-
cally decomposed. As hydrogen is released, the increasing hydroxyl concentra-
tion permits stable formation of practically insoluble magnesium ammonium
phosphate and calcium phosphate precipitates and the flocculent precipitate of
magnesium hydroxide. The magnesium hydroxide floes occlude other suspended
solids, and the floes are floated to the surface by the hydrogen gas formed. The
oxygen and chlorine released at the cathode also help to disinfect the product water
(35).
The equipment required for this electrolytic treatment would include a rectifier to
supply direct current power, electrodes, a waste collection system, and a sludge
collection and disposal system. In an attempt to avoid the high power costs for water
of low conductivity, the idea of adding chemicals to approximate the conditions
used in the Norwegian and Italian studies was briefly investigated. However, the
cost of chemical addition would again raise the operating cost to at least the $2.00
per thousand gallons of waste treated as quoted for the low salt domestic wastes.
The effluent from the pilot plants constructed in Norway (35) was apparently high
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quality with a very low number of bacteria. After filtration the effluent could
possibly be used for all household purposes except drinking. The sludge produced
could probably be handled similarly to septic tank solids.
The U. S. Navy is testing a device which mechanically separates and incinerates
waste solids, which are transported by a seawater flush, and electrolytically treats
the remaining liquid. Electrolysis produces minute bubbles of hydrogen, oxygen,
and chlorine which float suspended solids to the surface where they are skimmed off.
The chlorine and oxygen additionally act as oxidants and are effective in the control
of disease causing microorganisms (44). This unit has been extensively tested and
when not plagued by minor mechanical difficulties has bettered effluent standards of
1000 coliform/100 ml, 50 ppm BOD, and 150 ppm suspended solids.
An electrolytic method is also being investigated by the space agency as one of the
steps in the processing of urine for reuse. This method utilizes an electrochemical
oxidation process to decompose urea and other organics into hydrogen, nitrogen, and
carbon dioxide. It is expected that a combination of this method with electrodialysis
can produce acceptable product water from urine at a total operating cost of about
190 watt-hours per pound (approximately $31.70 per thousand gallons). The equip-
ment would also be relatively expensive (5).
In another electrolytic process proposed for an aerospace system, the water and
waste mixture is electrolytically decomposed to hydrogen at the cathode and oxygen
at the anode. When the oxygen and hydrogen are recombined, pure water is formed.
When the two gases are combined by combustion, the high temperatures attained are
sufficient to completely oxidize any volatile organics. Another approach is to
recombine the oxygen and hydrogen in a fuel cell to obtain useable electrical power,
which would partially offset the power required for electrolysis, (4, 6).
Such an electrolysis system would require a waste collection system, a source of
direct current, and a device to recombine the hydrogen and oxygen to produce water.
A fuel cell could be used to recombine the hydrogen and oxygen and recover some
of the power, or if the hydrogen and oxygen were recombined by combustion, heat
recovery could be practiced to conserve power. Suitable equipment is not readily
available but operating costs can be roughly estimated (assuming 75% power recovery)
to be approximately $70.00 per thousand gallons. The recovered water could be
used for all purposes and the waste would be relatively easy to handle; but the ex-
cessive power requirements and present inefficiencies in power recovery apparatus
should make further analysis of this system unnecessary in this study.
MISCELLANEOUS PROCESSES
Oxidation
Oxidation is the process which currently dominates the domestic waste treatment
field. Biological oxidation is used in sewage treatment almost exclusively and chlorine
chemical oxidation is the most popular method of water disinfection. Organic wastes
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are oxidized to carbon dioxide, water, and oxides of nitrogen and other elements.
New techniques of inducing oxidation and new or less expensive oxidants may permit
more effective water and waste treatment in the future. A comprehensive listing of
oxidants for waste treatment is included in the series of studies for Advanced Waste
Treatment by the Federal Water Pollution Control Administration (1). One company
has reportedly developed a system utilizing gamma radiation to induce oxidation for
a home sewage treatment unit (Chemical and Engineering News, April 21, 1969).
We have no additional information on this unit, but the AWTR-19 Summary Report
(2) estimated that in large installations the cost would be least $0.50 per 1000 gal.
At high temperatures and pressures organic material in a liquid suspension can be
rapidly oxidized by oxygen in a pressurized apparatus. This technique, wet
oxidation, is gaining acceptance for the treatment of municipal sewage sludges and
is being tested as a method of shipboard sewage treatment (38, Marine Engineering
Log, 1967). The process has also been tested for aerospace use in the treatment
of waste solids collected from other water purification systems and for the
recovery of water in feces (98).
Simple incineration has been successfully used to oxidize human wastes in isolated
locations and has been suggested for use on watercraft. However, an air pollution
problem could be expected if the use of incineration became common. The problem
may not, however, be much more acute than the air pollution from individual heating
units.
For the household, the oxidation techniques that seem most likely to be used in the
near future are the oxidation of waste solids by incineration and chemical oxidation
for disinfection of treated water. Incinerator toilets capable of disposing the sanitary
wastes from an eight member family are commercially available; some can even
accommodate the rinsing of diapers. The incinerator toilets can effectively eliminate
water pollution problems but introduce the possible danger of air pollution. Using
manufacturers' data on fuel and power consumption and assuming normal usage,
the operation of the incinerator toilet would average slightly more than $17 per
person per year and cost $400 to $600 for purchase and installation.
The use of the wet oxidation technique to treat wastes of the nature and volume of
household wastes would cost about $40.00 per thousand gallons. The effluent would be
stable but not fit for any reuse without extensive additional treatment.
Chemicals have been widely used for disinfection and many different types of equip-
ment are available to dispense disinfecting chemicals. Chlorinators, for example,
can be purchased for $150 to $600 and operated for approximately $0.08 per
thousand gallons of water treated.
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Chemical-Mechanical Removal of Contaminants
Many of the mechanical means of water and waste treatment such as sedimentation,
filtration, and adsorption can be aided by the addition of proper chemicals. Lime
and soda ash are used to precipitate the ions causing hardness in water. Aluminum
and iron salts are used to coagulate suspended and colloidal solids prior to sedimen-
tation or filtration. Still other chemicals, such as activated silica and various
poly electrolytes, are used to aid coagulation by stimulating the formation of floe
particles. Activated carbon is commonly used in the removal of taste, odor, and
color by adsorption. The series of publications by the Taft Sanitary Engineering
Center on advanced waste treatment research provides an extensive discussion on the
use of these chemical-mechanical techniques in the treatment of waste water.
Chemical coagulation and activated carbon adsorption were the treatments chosen
in a study for the U. S. Army on the renovation and reuse of kitchen, laundry and
shower wastewaters for all purposes except drinking and food preparation (37).
A system utilizing coagulation, sedimentation, filtration, and carbon adsorption has
been developed to treat the waste water from coin operated laundries, (85). A
similar system installed in the Virgin Islands is reportedly treating the laundry
waste water for reuse.
New innovations are also being applied in simple filtration. Multimedia filter beds
have been developed to achieve longer filter life and more efficient utilization of
the filter depth. New filter systems have been developed to remove even bacterial
sized particles. A study of water reclamation techniques for aerospace use showed
a multifilter system (particulate removal, carbon adsorption, and ion exchange) to
be most suitable for reclamation of the wash waters and dehumidification condensate
on space voyages of intermediate lengths (94).
Most of the chemical-mechanical contaminant removal techniques are relatively
inexpensive when applied on the scale of community water treatment plants, but
become increasingly costly in small installations because of the chemical handling
costs and the supervision required. To date, few automatically controlled systems
have been marketed for household use. Filtration is practiced in rural areas to
treat water supplies of uncertain quality for household use. Slow sand filtration
and filtration through commercially available pressure filters of sand, carbon and
prefabricated cartridges were evaluated in a study at the Ohio Agricultural Experi-
ment Station (42). A slow sand filtration apparatus could be supplied for approx-
imately $120.00 and could be operated for lŁ to 26 per thousand gallons (not
including the cost of pumping water from the filter). Pressure sand filters require
less space than slow sand filters but are more expensive to operate and produce a
lower quality effluent. Pressure sand filters are sold for about $120. 00 and process
the water at approximately 10j<{ per thousand gallons. Cartridge filters are avail-
able for many filtration tasks. Swimming pool filters including pump are available
at $130.00 and filter gross solids at a cost of approximately $. 07 per thousand
gallons. Other cartridge filters are available to remove various solids down to
0.5 microns in size.
75
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Collection and Storage
Collection and storage of wastes until a disposal site is available has been practiced
by airlines and watercraft for years. The wastes are merely stored until they can be
disposed of. Obviously, as the volume to be disposed decreases, the time between
dumping increases and the economy is greater. One commercial company now offers
a water closet which recycles disinfected flushing water and reportedly collects and
stores wastes from 80 to 100 uses when primed with only four gallons of water (38).
Systems for collection and storage of waste are widely used for boats, travel trailers,
and long distance trains, busses, and aircraft. Removal and disposal of the collected
wastes is a nuisance most people would not tolerate in their homes. Any system for
the home should therefore be designed for direct discharge to sewer or septic tank.
Such a recycle toilet with a discharge pump can be purchased for approximately
$280.00 and can be operated for about $. 01 per flush including disinfection (a yearly
cost of $18 to $19 per person). Laboratory tests indicated that the chemical used for
disinfection would not hinder either anaerobic or aerobic treatment of the collected
wastes.
Solvent Extraction
Solvent extraction is a process in which the water, but not the contaminants, is
dissolved in a solvent. The water-solvent solution is then separated from the
mixture and separated from each other by distillation (103). Solvent extraction
does not appear suitable for adaptation to household use. The method requires an
extraction column which must be maintained at the proper temperature, a tank in
which to separate the water-solvent solution from the waste mixture, and distillation
apparatus to remove the water and recover the solvent. Also, pilot plant installations
have experienced difficulty in completely removing the solvent after treatment.
Preliminary cost estimates for the solvent extraction technique in large installations
approach $. 50 per thousand gallons. Household operation would be much more
costly.
Solid Hydrate Formation
Certain hydrocarbons will form addition compounds with water which are called
hydrates. The hydrates are solids that can be separated from the water-waste
mixture by filtration. This process thus depends on a fine straining process
following the hydrate formation. As in the freezing process temperature and pres-
sure control and separation of the solid phase from the mother liquid pose significant
problems which are being studied at industrial and institutional laboratories (76, 62).
The hydrate technique of water purification involves most of the same problems
encountered in the conventional freezing processes. In addition, provisions must be
made to recover and recycle the hydrocarbon after it has been removed from the
water. Temperature and pressure control are also essential in the hydrate forma-
tion. Operating costs would probably be at least as high as those of the freezing
techniques.
76
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Maceration-Disinfection
Maceration-disinfection is a technique with little value for the prevention of pollution
by treatment of wastes, and its capability for disease prevention through disinfection
is often questionable. Maceration disinfection has been used to treat wastes from
watercraft by grinding the wastes to small sizes and adding a disinfectant to kill
bacteria. The process has been only partially successful in that the grinding is not
always complete and the disinfection is not completely effective. In addition, the
treatment does not remove or effectively change any of the polluting substances (38).
77
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VI
ENGINEERING STUDY AND EVALUATION OF PROCESSES FOR WATER
CONSERVATION AND WASTE TREATMENT
This section explores the practicality of the various combinations of current water
and waste treatment techniques which appear promising for the flow reduction or
treatment of household waste waters. Rather than making a detailed examination
of all the possible systems, the large number of treatment or flow reduction tech-
niques was first reduced by a qualitative evaluation. Then a technique for the com-
prehensive analysis and evaluation of household water and waste systems is developed
and applied to some of the treatment schemes already discussed.
Tables XI and XH list the various means discussed for reducing water usage and the
various techniques for treating the wastes produced. There are hundreds of different
ways in which the water conserving devices and the various treatment techniques
could be integrated into a household water and waste handling system. To facilitate
the screening of all the possible systems for water and waste handling, the problems
associated with possible changes in the present water and waste water systems were
analyzed. The typical home plumbing system (figure 2), the uses made of water at
each of the supply points (table n), and the pollutants introduced at each drain
(table VII) were evaluated to determine a relative order for the quality of water
required at each supply point (table xm). A comparison was then made of the quality
of the various effluent streams and the quality required at the supply points so that
the treatment required for reuse could be estimated.
Figure 9 shows the whole realm of reuse possibilities for household water-waste
systems. Technically, the reuse of waste water from any appliance or drain is
possible, though possibly not economically or aesthetically feasible, at any supply
point or for any purpose if it is given suitable treatment and a suitable piping system.
In the figure, we have used explicit criteria for the decision as to the feasibility of
using waste waters from the various sources at the various points of use. For
example, water from the bathtub or shower drain for reuse in the washing machine
is coded S , the S meaning suitable with a minor degree of physical and chemical
treatment, and the subscript A indicating that there may be aesthetic grounds for not
using this reuse combination.
Assumptions used throughout this evaluation section were (1) that reclaimed water
would not be used for drinking and cooking, (2) that water from any outlet may
occasionally be ingested, and (3) that homeowner acceptance of dirty looking water
will be low even though it might be suitable for its intended use. Thus, the water
78
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Table XI. Water Savings Plumbing Devices
Hardware Device
1. Limiting Flow Valves
for Shower
2. Limiting Flow Valves
for Lavatory
3. Limiting Flow Valves
for Kitchen Sink
4. Aerator for Lavatory
and Kitchen Sink
5. Batch-type Flush
Valve (1) for Water
Closet
6. Batch-type Flush
Valves (2) for Water
Closet
7. Urinal with Batch-
Type Flush Valve
8. Shallow Trap Water
Closet
9. Dual Cycle Water
Closet
10. Vacuum Flush Toilet
(for 100 Homes)
11. Vacuum Flush Toilet
(for Single Homes) 22.5
12. Washing Machine with
Level Control
13. Recycle Toilets
Water
Savings
gpcd +
6
0.5
0.5
0.5
7.5
15.5
7
7.5
17.5
22.5
22.5
1.2
24.7
Estimated Installation
Costs
Matl.
$
35
45
45
2
75
120
150
80
100
-
Labor
$
15
23
23
0
30
38
25
30
30
-
Total
$
50
68
68
2
105
158
175
110
130
295
1520
35
300
0
25
35
325
+ gal/eapita-day (gal/person/day)
79
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Table XII. Techniques For Treatment Of Waste Waters
Estimated Average Costs (from data in the literature)
00
o
Technique
Anaerobic Treatment
Aerobic Treatment
Air Evaporation
Distillation
Freezing
Electrodialysis
Reverse Osmosis
Electrolytic Treatment
Electrolysis
Incinerator Toilets
Wet Oxidation
Disinfection
Gravity Sand Filtration
Pressure Sand Filtration
Cartridge Filtration
Solvent Extraction
Equipment
& Installa-
tion Cost
$1100
1200
700*
1000
1000*
150
150
500 *
300 *
500
1000*
200
120
120
130
_.__..
Operating Costs per
Thousand Gallons Not
Including Amortization
Less than $0. 01
$ 0.60
56.00
4.00
8.00
1.50
8.00
2.00
70.00
17.00 per person/yr.
40.00
0.05
0.02
0.10
0.10
10.00
Comment
Most common method of waste disposal
Treatment of all Wastes
Cost for mineral removal only
Mineral removal only.
Cost for mineral removal only
Usually used for concentrated wastes
Unsuitable
*household sized systems not commercially available.
-------
00
M
Technique
Gas Hydrate Formation
Maceration Disinfection
Coagulation, filtration
Carbon filtration
adsorption
Table XII. (Cont'd)
Estimated Average Costs (from data in the literature)
Equipment Operating Costs per
& Ihstalla- Thousand Gallons Not
tion Cost Including Amortization
$ $ 10.00
110 50.00 per person/yr.
600 * 3.30
600* 1.60
Comment
Unsuitable
Unsuitable
Treatment of all wastes
Cost for treatment of non sanitary wastes only
*household sized systems not commercially available.
-------
Table XHI. Relative Levels Of Water Quality Requirements
Order of Water Quality Requirements (Highest Quality First)
1. Drinking and Cooking
2. Dishwashing
3. Bathing
4. Clothes Washing
5. Household Cleaning and General Purpose
6. Toilet Flushing
Order of Supply Points as Related to Water Quality Requirements
1. Kitchen and Bathroom Sinks, Hot Water Heater
2. Dishwasher
3. Shower, Bathtub, Set Tub
4. Washing Machine
5. Outdoor Faucet, House Heating System
6. Toilet Bowl
82
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Potential Household Water Sources
rH
ft
ft
Ł3
CO
-------
for any reuse must be biologically safe and contain no chemical substances considered
dangerous to health when accidentally consumed. Also the water supplied to any
point in the system where drinking or cooking water is commonly drawn must be
connected to a drinking water supply. For example, both hot and cold water supplied
to the bathroom and kitchen sinks must be taken from a safe drinking water supply.
Present practices would dictate that only two classes of water could be used in the
household. Most people have at some time obtained water for drinking from every
supply point in the house (bathtub, shower, laundry, outside faucet) except from
the water closet; and, therefore, if present practices are to continue, the only pur-
pose for which non-potable water could be used would be toilet flushing. Present
practices could be changed, however. People could be educated not to use all the
supply points for drinking. Dual quality water systems have been used in some
areas for years. In sections of the West brackish water systems are used for many
non-critical purposes to conserve a limited fresh water supply. Many ships use a
seawater system for toilet flushing, deckwashing, and fire fighting. To encourage
the safe use of multiple quality water systems, a reminder of the lower quality,
such as color, odor, or taste, could be added to the water; in addition the outlets
themselves could be colored or shaped differently. Some people may point out that
small children may not recognize these danger signals; but this danger would be no
greater than in the present situation in which the water supply most accessible to
small children is in the toilet.
PRELIMINARY ECONOMIC ANALYSIS
After review of the problems and the requirements that must be met, the various
systems were then subjected to a preliminary economic evaluation. Most people
are interested in pollution abatement and are willing to encourage the spending of
government money in the pollution abatement program. However, they are much less
willing to spend their own money for a private pollution control measure when their
neighbors are not also compelled to do so. Thus, few homeowners are likely to put
any device into their homes that is not specifically required by law, unless it can be
shown that the device will cost less (or at least not more) and will require very little,
if any, more maintenance than their present system.
For this reason, all the treatment techniques considered in the previous sections
were examined from an order-of-magnitude cost viewpoint to eliminate those schemes
that would be economically unacceptable to the average homeowner. Each proposed
treatment or waste reduction system is compared to the cost of the present water and
sewerage system at homes with central water and sewerage and at homes with septic
tank systems on good, fair, or poor soils.
The cost figures were taken from many sources including reports from the Office
of Saline Water, the Public Health Service and the Federal Water Pollution Control
Administration. All assumptions were slanted toward making the processes less
expensive, so that no process would be unnecessarily eliminated.
84
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The general assumptions used throughout the comparison were:
a. Each system will be installed in an "average" home as described on
page 8 with a four member family having an "average" water use of 255
gallons per day distributed as follows:
27 gal. kitchen & drinking
88 gal. bathing & hygiene
40 gal. laundry & cleaning
100 gal. toilet flushing
b. Electrical energy - $0.02/KWH
c. Fuel oil - $0.15 per gal.
d. Water rate - $0.42 per 1000 gal.
e. Sewerage rate - $0.44 per 1000 gal.
f. Cost of septic tank soil absorption - as discussed on page 42,
The results of the cost comparison are shown in table IVA included in the appendix.
to this table, column (1) represents the annual per person cost of purchasing, install-
ing, operating, and maintaining the waste treatment or flow reduction system.
Column (2) is the average annual cost of the water used per person, column (3) is
the average annual per person cost of disposing of the waste water; and column (4)
is the total yearly cost of water and the disposal of waste water for one person.
Column (5) compares the total cost of the system being considered with the cost of
the conventional systems now being used. (Item 1).
Each new system evaluated is considered for installation in comparison with four
generalized conventional systems: (a) in areas having sewer service and average
water costs, (b) in areas having soil absorption systems in good soil, (o) » «*»
having soil absorption systems with fair soil, and (d) in areas having soil ab*orption
systems with poor soil, (soil classifications according to Thomas (87)). * addition
(e) shows effect of a low water rate ($0. 20/1000 gal.) and (f) shows the effect of a
very high water rate ($1.50/1000 gal.) for the system with sewers.
This brief economic analysis provided many enlightening comparisons and per-
litted recommrdationsyfor the further investigation or the elimination of various
Schemes. The information from the cost comparison table is summarized below:
1. Reduction of water usage appears to be economically the most feasible means
of reducing waste flow from the home.
85
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2. Flow control faucets are of marginal value when replacing workable faucets,
but are definitely warranted for new homes and for necessary replacements.
Faucet aerators would apparently be a useful addition to all faucets for
convenience as well as water savings.
3. Flow control showers are an inexpensive means of economically saving con-
siderable quantities of water.
4. The use of pressure flush valves to reduce water flow does not appear as
advantageous as the redesign of the toilet bowl to allow adequate flushing
with less water.
The pressure flush valve could be advantageously used with the redesigned
toilet bowl. Siphons, as used in the English water closets, would also
provide better volume control than the system presently used in the United
States.
5. The vacuum flush toilet for the individual home is too expensive because of
the high cost of the accompanying equipment when used for single homes. As
mentioned on page 64 the use of the vacuum flush system for groups of
dwellings or multiple dwelling units was considered to be outside the scope
of this study.
6. The major economic disadvantage of the recycle toilets is the high cost of
the chemical used for disinfecting the recycled flush water. Development of
a suitable, lower cost disinfectant could make their use much more practical.
There could be a problem with acceptance of reused flush water in the home,
but this objection does not appear insurmountable.
7. Incinerator toilets are excessively costly to operate and maintain for
family use. For certain applications, such as weekend cabins which are
used sporadically, the incinerator may be the most economical system, but for
normal continuous use, the incinerator toilet can not economically compete
with conventional systems.
8. The analysis of the system to reuse wash waters for toilet flushing reveals
several very significant facts. The treatment and the quality standards
required for flushing water are minimal and the costs are thus relatively
low in comparison with those for any other reuse. Yet this treatment and
reuse is economical only in fair and poor soil areas.
9. The additional treatment of the non sanitary waste waters by distillation,
reverse osmosis,carbon adsorption, or a multifilter system for use as
laundry and bathing water as well as toilet flushing does not appear econo-
mically feasible.
10. The treatment of all waste waters by distillation and reuse for all purposes
but drinking is also economically unattractive.
86
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11. Aerobic treatment is competitive with anaerobic systems in poor soil areas.
In such poor soil areas, some reuse may also be warranted.
12. Electrolytic treatment for disposal is not economical for most areas because
of the low conductivity of the water.
Based on these observations from table IVA, the systems that warrant further
discussion are the various means of restricting water usage, reuse of wash waters
for toilet flushing, and the use of aerobic treatment systems in poor soil areas
with the possibility of treating and reusing portions of the aerobic effluent.
ADDITIONAL ANALYSIS OF PKOPOSED SYSTEMS
From the information available in the literature and the limited information supplied
by the equipment manufacturers there is not enough actual data to perform an accurate
and detailed examination for most of the proposed water reduction or waste treatment
schemes. We have, however, developed criteria suitable for an actual detailed
evaluation and have presented examples pertinent to this discussion.
Criteria For A Semi-Quantitative System Evaluation
Definite evaluation criteria were established to facilitate an objective comparison
of the possible flow reduction and treatment schemes. The criteria chosen and their
relative values are given in the following table. The reasons for this selection are
then discussed.
Criteria Weighted Value (%)
1. Initial Cost 20
2. Operating Cost 20
3. Reduction in Waste Volume 20
4. Effluent Quality 10
5. Operating Attention 10
6. Aesthetics 1°
7. Safely 5
8. Compatibility with home plumbing 5
All the evaluation criteria can be grouped under cost, utility, or household
acceptability. These main groups are further broken down to make evaluation easier.
Cost is represented by initial cost and operating cost; utility is represented by
reduction in waste volume and effluent quality; household acceptability is represented
by operating attention required, aesthetic factors, safety, and compatibility with
home plumbing. Thus, of the total evaluation 40% is based on costs, 30% on utility,
and 30% on household acceptability.
87
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Cost, utility, and household acceptability are all essential for the success of a
household waste treatment or volume reduction system, but cost was given the greatest
weight because of its tendency to override the others. For example, excessive costs
would readily cause a system of great utility and desirability to be rejected, while
low costs could induce acceptance of systems with some undesirable features and of
limited utility.
Under the heading of cost, initial cost and operating cost were given equal weight.
Reduction of waste volume was considered of somewhat greater value than effluent
quality because all cases produce some waste, requiring treatment either at the source
or in a municipal system, and reduced volume allows greater efficiency in this treat-
ment. Safety is the most important factor for household consideration, but we are
assuming that all systems considered will provide adequate safeguards against
disease or accidents. Thus, in this discussion safety is considered secondary to
operating attention and aesthetic factors. Compatibility with present systems is
also given a lesser value, since it is already a factor in the initial cost and is a
lesser problem in new installation where such systems are most likely to be
accepted.
1. Initial Cost - Initial cost is meant to include all expenses of installing
and preparing a system of waste volume reduction or waste treatment for
reuse. This initial cost will include the purchase cost of equipment
required and installation costs, including the cost of alterations in the
present system needed to allow the installation and use. Costs should
not include items normally in the home. Items which are normally included
in a household system but are not required with the proposed system should
be counted as savings. The initial cost rating of systems will be determined
as follows:
T .,. , , -. ,. Initial Cost of Present System .
Initial Cost Rating = * X 20
Initial Cost of Proposed System
2. Operating Cost - Operating cost includes all direct material, power,
and labor expenses incurred in the operation of the proposed system.
Operating cost does not include a cost for the duties which would normally
be performed by the homeowner; these are accounted for under the heading
of "Operating Attention". Operating costs will include the cost of water
used and the cost of disposing of any waste water.
_ .. ,_, . _ ,. Present Operating Cost
Operating Cost Eating = \~ ^ f X 20
6 & Operating Cost of Proposed System
88
-------
3. Reduction in Waste Volume - Reduction in waste volume is very simply
computed as the decrease in water requirements, since normally all water
taken in (not including water for irrigation) is eventually discarded to the
waste disposal system.
Reduction in Waste Volume Rating = (1.0 - water used in proposed system
water used in normal system '
4. Effluent Quality - The quality of the effluent which is discarded as waste
from the system is very important in that it accounts for possible difficulties
of transporting the waste to the final treatment center (including problems
with corrosion, solids, viscosity, etc.). and the difficulty of treating this
final waste at the treatment center.
Definite values for these parameters are not readily available and will
depend on the system and the type of final treatment proposed. Thus each
system must be individually considered. For the examples presented the
systems are given a subjective rating from 1 to 10 which is then discussed.
5. Operating Attention - Operating attention refers to the time that the home-
owner must spend in the normal operation and maintenance of the system for
reducing waste volumes or treating wastes. It does not include main-
tenance work that is normally hired through service firms or contractors.
Such maintenance is included in operating cost.
.. c ^ AiA ... Hours per yr with present system __,..
Rating for Operating Attention = e * r^~ j; X 10
0 Hours per yr with proposed system
6. Aesthetics - Aesthetics refers to the personal reaction of household members
to the use of the proposed technique for treating wastes or reducing the
volume of waste water discharged. This also is a rather subjective and
individually variable rating which will be discussed for each of the examples.
7. Safety - Safety is the term included as a measure of possible health hazards
associated with the presence and use of the various devices for treating
wastes or reducing the volume of wastes produced. All devices considered
should be designed to eliminate unusual safety hazards, but the remote
possibility of a disease or accident will of course exist. This rating will
therefore be an evaluation of the risk involved. The rating of each process
assigned will be individually discussed,
8. Compatibility With Present Designs - This term refers mainly to problems
that may arise from changes required in the way homes and utilities are
currently designed and built. It does not refer to simple rearrangements in
plumbing fixtures since these are included as part of the initial cost for
installation. It does refer to such things as changes in the requirements for
power, sewage lines, and home or lot sizes. Each process will be given
a subjective rating from 1 to 5.
89
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Evaluation Examples
This section presents some brief examples (using the remaining waste reduction and
treatment schemes) of the evaluation process and illustrates the kinds of problems
that need to be considered. Also included are two comparative examples of a dis-
tillation process that had been previously eliminated because of high costs. In
these examples, the water reduction or waste treatment device is compared with the
device it would replace in the present household. Faucets with aerators are com-
pared to faucets without aerators, shallow trap toilets are compared with the normal
toilet, etc. In each case a schematic diagram is used to represent the water use in the
household. Unless stated otherwise, the items in these examples are considered
to be installed in older homes with municipal water and sewerage service. In homes
with private waste disposal systems, the evaluation process would be unchanged, but
the emphasis shifts from the waste volume to the treatability and the disposal of
wastes. The evaluation emphasis might also have to be shifted in areas where water
or sewage rates are very high.
Faucet Aerators - Faucet aerators are now very common and are manufactured as
part of most faucet combinations because of the smooth even flow and the lack of
splashing. Aeration helps remove objectionable tastes and odors, and the aerated
stream of water is more efficient for rinsing than an unaerated stream. It should
be noted, however, that the splashless characteristics considered desirable and con-
venient may actually result in the use of more water, even though the aerated stream
itself is more efficient. This results from the tendency to use a higher flow rate and
often to let the water run between rinsing operations when there is less splashing.
The use of aerators in the bathroom lavatory and the kitchen sink can save about
two gallons of water each day. Probably half of this water is heated and an estima-
tion of costs involved should include this fuel savings. It should also be specifically
noted that these savings cannot be considered additional since they are already common
in most homes.
Aerators increase the cost of faucets only slightly and they reduce operating costs
and waste volume. Aerators do require some maintenance in the removal of mineral
deposits which accumulate in some areas. There is no effect on effluent quality,
safely or compatibility and the aerated stream is aesthetically more pleasing than
the unaerated stream. Cost estimates are shown on figure 10.
90
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C.-J-J Ł1**"-
Potable
Supply
r"
27 gpd 35 5
I i I
(aerator)
Kitchen Laundry Utility
1
80 8 100
1 1 4
(aerator)
Bath Lavatory Toilet
255 gpd
Waste
Disposal
COST ESTIMATES FOR A FOUR MEMBER FAMILY
Material Cost
2 aerators $1.50
Labor Cost
1/6 hr. (non professional)
Total Installation Cost
Expected Life
15 yr.
Cost Per Year
Maintenance and Power Cost Per Year
Cost of Water Saved Per Year
2 gpd (365 day/yr) x $.42/1000 gal
Cost of Power Saved Per Year
(1/2) (2 gpd) (365 day/yr) x $.67/1000 Kal
Cost of Sewerage Saved Per Year
2 gpd (365 day/yr) x $.44/1000 gal
Total Savings Per Year
Net Savings Per Year $.87- $.20
$3.00
0
$3.00
$ .20
0
.31
.24
.32
$ .87
$ .67
Figure 10. Household with Faucet Aerators
91
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Rating for Aerators
Initial Cost 19.2
Operating Cost 21.2
Reduction in Waste Volume 1.1
Effluent Quality 10.0
Operating Attention 7.0
Aesthetics 10.0
Safety 5.0
Compatibility with Present Designs
Rating
Flow Control Slower Heads - Flow control shower heads are merely more economical
replacements for the conventional type of shower heads. They can reduce the water
consumption from the usual 5 to 15 gallons per minute to about 3 gallons per minute
of showering. The total amount of water saved will depend on the water pressure of
the system and the personal habits of the bather. Using the values for our "average"
home where the present shower is assumed to deliver 5 gallons per minute and to last
3 to 5 minutes, the flow control shower heads will save 6 to 10 gallons of water per
shower. If showering is the method of bathing sixty percent of the time, the water
saved is approximately 2200 gallons per year for each person. At least three-
fourths of the water saved would have been heated and the cost of heating the water
is an additional savings. Assuming that fuel oil ($0.15 per gallon) is the source of
heat this saving is approximately $0.67 per 1000 gallon and the total savings in water,
sewage, and heating from flow control shower heads is thus about $3.00 per person
or $12.00 per "average" family for each year.
Flow control shower heads are manufactured by several leading manufacturers and
marketed at prices varying from $3.00 to $15.00. Installation varies from simply
screwing a new showerhead in place of the old one to complete replacement of the
piping back to the supply line. The first case can be easily handled by the home
owner in 5 to 10 minutes while a plumber would probably charge $10.00 to $15.00
in the second case. Using the higher costs mentioned above, the total cost of
converting to flow control shower heads would be $30.00, and the water and fuel
savings in the "average" home would amortize the purchase and installation expenses
in two and a half years. Thereafter the family would save twelve dollars per year.
For new homes, the increase in cost over conventional devices would be much less
than the cost of conversion in an older home, and savings would be correspondingly
greater.
92
-------
The flow control shower-heads cost approximately 10% more than the conventional
shower heads but cost less to operate (reduced water and heating costs) and demand
no additional maintenance or operating attention. The quality of the shower effluent
is unchanged except for a slight increase in contaminant concentration. The reduced
volume fixture does provide a pleasant and adequate shower for cleansing. There
may, however, be some aesthetic objection to the reduced flow rate because many
people particularly enjoy a shower at full force (such a shower often consumes more
water than a tub bath). Safety and compatibility are unchanged.
Rating for Flow Control Showers
Initial Cost 18.0
Operating Cost 26.7
Reduction in Waste Volume 5.0
Effluent Quality 10.0
Operating Attention 10.0
Aesthetics 8.0
Safety 5.0
Compatibility with Present Design 5.0
87.7
Low Trap Water Closets - The conventional household water closet uses 4 to 6 gallons
of water per flush and flushing water can amount to more than one third of an
individual's daily water usage. The amount of water required for flushing is governed
by aesthetic criteria for sufficient water to effectively remove the wastes from the
toilet. Be redesigning the toilet bowl and the water trap various manufacturers
are producing toilets which require only about 3-1/2 gallons for an adequate flush,
thus saving an average of 1-1/2 gallons per flush or for the "average" individual,
about 7-1/2 gallons per day, 2740 gallons per year. Again assuming the "average"
rates this is equivalent to a savings of $2.35 per person per year or $9.40 for the
"average" four member family.
The low trap toilets are no different than the normal toilets in operation or
appearance and the only evaluation parameters that would change are initial cost,
operating cost, and waste volume.
93
-------
Potable
Supply
23<
2'
j
7 gpd 3i
> 1
(aerator)
Kitchen
5 5
r 1
Laundry
6
, J
Utility
0 E
[ |
Plow Con.
Showers
Bath
K
| |
(aerator)
Lavatory
30
r
Toilet
) gpd
Disposal COST ESTIMATES FOR A POUR MEMBER FAMILY
Material Cost
flow control shower head $15.00
Labor Cost
2 hr. $7.50/hr.
Total Installation Cost
^rpocted Life
Cost Per Year
Maintenance and Power Cost Per Year
Cost of Water Saved Per Year
Cost of Power Saved Per Year
Cost of Sewerage Saved Per Year
Total Savings Per Year
Net Savings
$15.00
15.00
$30.00
2.00
0
3.70
4.40
3.90
$12.00
$10.00 yr.
Figure 11. Household with Flow Control Showers
94
-------
Rating for Low Trap Water Closets
Initial Cost 16.5
Operating Cost 28.6
Reduction in Waste Volume 6.0
Effluent Quality 10.0
Operating Attention 10.0
Aesthetics 10.0
Safety 5.0
Compatibility with Home Plumbing 5.0
Total 91.1
Automatic Flush Valve Water Closets - The automatic flush valve offers several
advantages for conservation of water and for design changes in the bathroom. The
flush valve operates directly from the water supply line and requires no tank. The
absence of a tank could allow the utilization of additional space in the bathroom.
Flush valve operation demands larger piping for the household, at least to the
water closet, in order to supply water at a sufficient rate to start the flush siphon.
Therefore, installation of flush valves would require replacement of existing piping
in older homes and the use of larger piping for new homes in addition to the cost
of purchasing and installing the valves.
The system offers the advantage of more controlled volumes of flush water. The
flush mechanism can be set to deliver a volume of water sufficient for flushing and
no more. Unlike the conventional flush mechanism, where additional water is lost
as the tank refills, water flow stops when the flushing action is over. Also, with
the tanks water often leaks continuously and unnoticed between flushes. If the
automatic flush valve begins malfunctioning it is immediately apparent and repairs
can be made. The flush valve offers a ready means of providing a dual flush, which
would use less water to flush away liquid wastes. This could be accomplished simply
by mounting two valves in a parallel circuit. The automatic flushing valves
are also adaptable to and could be advantageously used with the shallow trap toilets.
Initial costs would be higher because of the flush valve cost and the larger size
piping that would be required. Despite possible maintenance costs, the total operating
cost would be lower because of the savings in water and sewerage. Initial cost and
volume reduction vary with the use of single flush or dual flush systems. Effluent
quality, operating attention, aesthetics, safety, and compatibility remain unchanged.
95
-------
225 gpd-
Potable
Supply
270* 35 5 80 8 70
\ J 1 1 \ 1
(aerator)
Kitchen
laundry
Utility
Bath
(aerator)
Lavatory
Toilet
f
225 gpd
Waste Disposal CQST ESTIMATES FOR A POUR MEMBER FAMILY
Material Cost
(1 shallow trap water clbset) $70.20
Labor Cost
4 hrs. $7.50
Total Installation Cost
Expected Life 20 yearn
Cost Per Year
Maintenance and Power Cost Per Year
Cost of Water Saved Per Year
Cost of Power Saved Per Year
Cost of Sewerage Saved Per Year
Total Savings Per Year
$ 70.20
30.00
$100.20
5.01
0
4.60
0
4.80
$ 9.^0
$ 4.39
Figure 12. Household with Shallow Trap Water Closets
96
-------
Rating for Automatic Flush Valve Water Closets
Single Dual
Flush Flush
Initial Cost 9.3 7.4
Operating Cost 27.6 33.9
Reduction of Waste Volume 6.0 9.2
Effluent Quality 10 10
Operating Attention 10 10
Aesthetics 10 10
Safety 5 5
Compatibility with Home Plumbing 5 5
82.9 90.5
Reuse of Wash Water for Toilet Flushing - The reuse of wash waters for flushing
toilets is a scheme in which the water from the laundry and from bathing is collected
and used as the flushing liquid in the water closet, thus saving the amount of water
normally used for toilet flushing. This use of waste wash waters for toilet flushing
is one of the simplest and least expensive methods of conserving water through
reuse. The water for reuse for flushing toilets does not require high standards,
because it is not to be ingested or to come in contact with the body. It does not have
to be heated, and therefore requirements of a heating system need not be considered.
The detergents from laundry operations should make the water safer from a health
viewpoint since many detergents are bactericidal. Also, the bad taste of soaps and
detergents should discourage small children who might accidentally ingest the water.
The main treatment problem is to make the water aesthetically acceptable to the
average housewife.
Possible aesthetic parameters for rejection would be foaming, suspended solids,
odor, and color. Suspended solids can be removed by filtration; if odor, foaming,
and color are problems, the causative agents could be removed by activated carbon.
In the experimental unit used by McLaughlin (55), odor, color, and foaming were no
problem and suspended solids were removed by filtration through a swimming pool
(cartridge type) filter.
The physical requirements of the system are collection of the waste waters,
storage of this water until usage, and a means of supplying the water to the water
closet for use. To collect the water, existing drains must be rerouted or replaced,
97
-------
209 to *
225 gpd
Potable
Supply
27 gpd 35 5
W w ^r
(aerator)
Kitchen
Laundry
Utility
80
Bath
8 70-54
, (D|(2)
1 I
(1) (2)
Flush
(aerator] Valves
Lavatory Toilet
f
209-225 gpd
Wast-.«> Disposal
COST ESTIMATES FOR A
FOUR MEMBER FAMILY
1 Valve 2 Valves
Material Cost
1 or 2 flush valves $40, piping $20
Labor Cost
5-6 hr. $7.50/hr.
Total Installation Cost
Expected Life !5 yr.
Cost Per Year
Maintenance and Power Cost Per Year
Cost of Water Saved Per Year
Cost of Power Saved Per Year
Cost of Sewerage Saved Per Year
Total Savings Per Year
Net Savings
$60.00
37.50
$97.50
$ 6.50
.75
4.60
0
4.80
$ 9.40
$ 2.15
$100.00
45.00
$145.00
$ 9.65
1.50
7.05
0
7.40
$ 14.45
$ 3.30
Figure 13. Households with Automatic Flush Valves for Water Closets
98
-------
and a tank provided for storage. A filter is required to protect the flushing system
and the pump used to lift the water to the water closet from abrasive solids. Also,
a pressure tank is required to supply pressurized water to the water closet. The
pressure tank could possibly be eliminated by slight modifications of the pump and
water closet.
Initial cost, operating cost, and operating attention will increase with this system,
while waste volume will be substantially decreased. Effluent quality and safety
will not change appreciably, but aesthetic and compatibility factors will depend on the
particular circumstances.
Initial Cost 4.2
Operating Cost 17.4
Reduction in Waste Volume 20.0
Effluent Quality 10.0
Operating Attention 9.5
Aesthetics 9.5
Safety 5
Compatibility with Home Plumbing 4.5
80.1
Aerobic Treatment of Wastes - Several manufacturers of aerobic treatment systems
offer maintenance contracts with their treatment units so that no more homeowner
attention is required than for a septic tank. This service costs additional money,
but helps make the aerobic devices more acceptable to the health authorities who
recognize both the need for periodic maintenance and service and the tendency of
most home owners to neglect maintenance and service so long as possible. The
treatment system of many of the companies contacted is designed to be buried out of
sight like the septic tank with a similar soil absorption system for disposal of the
treated effluent. Many of the companies claim that the effluent from their treatment
plant is suitable for disposal to storm sewers or small water courses. However,
many health officials do not currently permit such disposal, and we have assumed
the necessity of using a soil absorption system in this analysis. The advantages of
the aerobic treatment are the greater absorption capacities that most soils exhibit
toward aerobic over septic effluents. Thus the absorption field can be made smaller
or assumed to last a longer period of time. In this example an absorption field
1/3 the size required for a septic tank effluent (87) is assumed to be adequate.
99
-------
155
Potable
Supply
80
27 gpd 35 5
44411
100
Kitchen
Laundry
Utility
Bath
155
Waste Dioposal
Lavatory
Ł
Toilet
Overflow
15
iollection
Tank
Punip
Tank
COST ESTIMATES FOR A FOUR MEMBER FAMILY
Material Cost
tanks and piping $95, pump & filter $140
Labor Cost
12 hrs $7. 50 AT.
Total Installation Cost
Expected Life
10 yr. (main components)
Cost Per Year
Maintenance and Power Cost Per Year
Cost of Water Saved Per Year
Cost of Power Saved Per Year
Cost of Sewerage Saved Per Year
Total Savings Per Year
Net Savings
$235.00
90.00
$325.00
32.50
3.65
16.10
15.30
3?.. 40
-$ 4.75
Figure 14. Households with Reuse of Washwater for Toilet Flushing
100
-------
In poor soils, the initial cost of the aerobic system may be substantially less than an
anaerobic system. The aerobic system requires power roughly equivalent to a home
freezer. There is no reduction of volume but the effluent is of high quality. Assuming
the use of a manufacturers service contract, operating attention increases only
slightly. Aesthetically, an aerobic plant is more operationally acceptable than a
septic tank, but the greater accessibility required for maintenance may make the
aerobic system more offensive to some home owners. Safety and compatibility are
relatively unchanged.
(Note that the aerobic system is compared to a septic tank in poor soil where the
size of the absorption field for aerobic effluent is assumed to be 1/3 that required
for a septic effluent)
Initial Cost 27. 7
Operating Cost 4.8
Reduction in Waste Volume 0. 0
Effluent Quality 15.0
Operating Attention 9.5
Aesthetics 4.5
Safety 5.0
Compatibility with Home Plumbing
Distillation of Wastes with Reuse for all but Drinking and Cooking - Although this
treatment scheme has already been eliminated by the preliminary cost analysis,
it is presented again as a comparative example of one of the more complicated treat-
ment schemes.
Available distillation devices cannot handle solid materials effectively without
excessive scaling. The most inexpensive method of removing and treating the solids
would be by sedimentation and filtration. These could be supplied by a septic tank
and a commercially available pressurized sand filter. This clarified liquid would
then be fed to the distillation apparatus. For simplicity it was assumed that the use
of a vapor compression device such as the Hickman still would be used and that the
significant operating problems had been solved. Also, it was assumed that 85% of
the feed water will be recoverable in the distillation process without significantly
increasing operating costs.
101
-------
Potable
Supply
27 gpd 35 5 80 8 100
t f * * t *
Kitchen
Laundry
Utility
Bath
Lavatory
Toilet
1
255 gpd
Aerobic
Treatment
Soil -Absorption
(poor soil)
COST ESTIMATES FOR A FOUR MEMBER FAMILY
Material Cost
aerobic plant $1200, soil absorption system $800
Labor Cost
included above
Total Installation Cost
Expected Life
20 yr.
Cost Per Year
Maintenance and Power Cost Per Year
Cost of Water Saved Per Year
Cost of Sewerage Saved Per Year (Cost of Septic
Tank System in Poor Soil)
Total Savines Per Year
Wpt* ^avlnffs
$2000
$2000
if 100
51
152
1
Figure 15. Aerobic Treatment in Place of Septic Tank in Poor Soil Areas
102
-------
55 gpd
'otable
>upply
"*" F
27 Igpd
>
Kitchen
"^
)
?5
Laundry
Settling
and
Digestion
Tank
p
Utility
^^^^f
Pump
Filter
100
*
p
Toilet
)lsinfeo-
tion
»
Pres-
surized
Holding
Tank
Hot
Water
Heating
Tank
COST ESTIMATES FOR A FOUR MEMBER FAMILY
Material Cost
pumps & pressure tanks $290, pre treatment $520,
distillation unit $1500, final treatment $250
Labor Cost
Total Installation Cost
Expected Life
15 yr.
Cost Per Year
Maintenance and Power Cost Per Year
pumping $22, pretreatment $12, distillation $160,
final treatment $30
Cost of Water Saved Per Year
Cost of Power Saved Per Year
Cost of Sewerage Saved Per Year
Total Savings Per Year
Net Savings
$2560.00
200.00
$2760.00
184.00
224.00
34.00
0
114.00
148.00
-$ 260.00
Figure 16. Distillation and Reuse: All Water in Poor Soil Areas
103
-------
The low temperature operation of this still would prevent the volatilization of many
organic materials but the product water would still require disinfection and carbon
adsorption treatment to make the effluent acceptable for health and aesthetic standards.
The initial cost and the operating costs of such a system are much higher than under
present systems and the cost savings in water and sewerage are small in comparison
with the costs. The parameters of operating attention, aesthetics, safety and house-
hold acceptability would also be adversely affected. The additional equipment re-
quires additional homeowner surveilance and maintenance. Under normal conditions,
the safety of the water should be insured by the multiple steps of filtration, distilla-
tion, adsorption and disinfection but the chance of malfunction exists, and the
knowledge of possible malfunction would cause some aesthetic reaction in addition
to the normal dislike for directly reusing waste water. There would be no major
design problems with such a system, but just the bulk of the equipment could cause
some concern.
Rating for Distillation and Reuse of All Wastes
Initial Cost 0.5
Operating Cost 8.2
Reduction in Waste Volume 17.3
Effluent Quality 10.0
Operating Attention 3.3
Aesthetics 8
Safety 3
Compatibility with Home Plumbing
Total
According to the ratings just presented, the order of desirability of the waste
reduction and treatment schemes is shown below followed by a similar ordering
as to net savings per "average family" per year.
Order of Rating Rating
1. Shallow Trap Toilets 91.1
2. 2 flush valves with toilet 90.5
104
-------
Order of Rating (Cont'd) Rating
3. Flow control showers 87.7
4. 1 flush valve with toilet 82.9
5. Reuse of wash waters for toilet flushing 80.1
6. Aerators 78.5
7. Aerobic treatment (poor soil areas) 71.5
8. Distillation and reuse of all wastes 54.8
Order of Net Yearly Savings ($)
1. Flow control showers $ 10.00
2. Shallow trap toilets 4.39
3. 2 flush valves with toilet 3.30
4. 1 flush valve with toilet 2.15
5. Aerators 0.67
6. Reuse of wash waters for toilet flushing -4.75
7. Aerobic treatment 1.00 (in poor soils)
8. Distillation and reuse of all wastes -260.00 (in poor soils)
When the rating order and the savings order are combined, the listing of the
processes in order of practicality becomes:
1. Shallow trap toilets
2. Flow control showers
3. 2 flush valves with toilet
4. 1 flush valve with toilet
5. Aerators
6. Reuse of wash waters for toilet flushing
7. Aerobic treatment
8. Distillation and reuse of all wastes
Figures 17 and 18 show the probable costs and savings that would correspond to two
of the possible combinations of these devices. Each actual application would be a
different and individual problem which could be solved in the manner outlined at the
beginning of this section.
105
-------
Potablew
Supply
115 gpd
100
o
to
o
p.
to
H
O
Pressure
Storage
*
Distil-
lation
Unit
Pump
Pump
40
300 gal. 30 gal.
COST ESTIMATES FOR A FOUR MEMBER FAMILY
Pressure
Storage
Tank
Hot Water
Heating
& Storage
3° sal'
Material Cost
pumps & pressure tanks ($250), pretreatnent $270,
distillation $1000
Labor Cost
Total Installation Cost
Expected Life 15 yr.
Cost Per Year
Maintenance and Power Cost Per Year
Cost of Water Saved Per Year
Cost of Power Saved Per Year
Cost of Sewerage Saved Per Year
Total Savings Per Year
Net Savines
$.1520
200
1720
114
34
22
23
45
-$103
Figure 17. Reuse of Non-Sanitary Wastes for Toilet Flushing After
Filtration, and for Laundry After Distillation
106
-------
205 gpd ^~"1
Potable
Supply
1
1 1
"'
27 gpd 35 5 60 8 70
1 1 1 1 1 I
(aerator^
Kitchen
Laundry
Utility
Bath
(aerator)
Lavatory
Toilet
205 gpd
to TJastc Disposal
COST ESTIMATES FOR A FOUR MEMBER FAMILY
Material Cost
1 shallow trap W.C. $70.20,1 flow control
shower $15, 2 aerators at $1.50
Labor Cost
6 hr. $7.50/hr.
Total Installation Cost
Expected Life
Cost Per Year
Maintenance and Power Cost Per Year
Cost of Water Saved Per Year
Cost of Power Saved Per Year
Cost nf Sewerage Saved Per- Year
Total Savings Per Year
Net Savings
$ 88.20
$ 45.00
133.20
6.45
0
8.10
4.37
Sn6?
$-.21.09
$14.64
Figure 18. Use of Flow Control Showers, Shallow Trap Toilets, and Aerators
107
-------
vn
SURVEY RESULTS
A postal survey of homeowners, architect-engineers, plumbers, and plumbing
equipment manufacturers was conducted to obtain representative reactions from the
people who would control the actual use of any schemes for reducing water usage or
improving waste treatment and to ensure that the opinions formed from the literature
survey were not contrary to popular practice or beliefs. The questionnaires were
prepared and distributed throughout the country so that any peculiarities or radical
differences in the replies caused by climatic or cultural variations in different areas
of the country could be recognized.
The response to the survey was relatively good as 387 homeowners, 40 plumbers,
29 architect-engineers, and 8 plumbing equipment manufacturers, representing 50%
of the equipment manufacturers contacted, 52% of the homeowners, 21% of the
architect-engineers, and 18% of the plumbers, filled out and returned the question-
naires. The higher return from the equipment manufacturers and homeowners was
probably due to the fact that many from these groups were personally contacted by
phone or in person by personnel from the different General Dynamics divisions around
the country. Many of the survey participants submitted additional suggestions and
comments on the environmental pollution problem in general and on particular points
in the different questionnaires. In addition, slightly more than half of the cooperating
homeowners asked to receive a summary of the survey results and conclusions.
The responses received showed no major differences in the opinions of the people;
from the various sections of the country; nor did the responses differ significantly
with the cost of the homes. Comparison of the answers from homeowners with sewer
connections with the answers and comments from homeowners with individual waste
disposal systems also revealed no significant differences.
The questionnaire distribution schedule and samples of the questionnaires with the
tabulated results of the survey are included in the appendix (tables VA through IXA).
The pertinent results related to the use of the water reduction devices and techniques
are shown in table XIV, and the following section presents a brief discussion of all
the survey results.
WATER SAVING FAUCETS AND SHOWERHEADS
As shown by table XIV, all of the groups surveyed were favorable toward the use of
the flow restricting faucets and showerheads. Most of the objections to these devices
seemed to stem from aesthetic rather than functional or economic considerations.
108
-------
Water Saving
Device or Technique
Table XIV. Summary Of Survey Results
Percent of Responses Which Indicate Acceptance for
the Use of These Techniques or Devices
Architect- Equipment
Homeowners Plumbers Engineers Manufacturers
Water Saving Faucets
or Shower Heads 87
Direct Flush Toilet
Valves 92
Toilets with Separate
Flush Cycles for Urine
and Feces
Home Urinals
87
49
90
79
75
72
79
37
56
24
90
77
43
43
Toilets that Disinfect
and Reuse Flush Water 46
The Reuse of Wash Waters
a. For Toilet Flushing 82
b. For Lawn Irrigation 82
21
68
86
86
109
-------
Some seemed to fear that showering enjoyment would be curtailed by the reduced
flow. One of the architects surveyed was opposed because he thought the flow
reduction was to be achieved through spring loaded, rather than flow restricting
valves.
The equipment manufacturers and plumbers predicted that the flow reduction devices
would be 10% to 30% more expensive to purchase and possibly somewhat more costly
to install, although no particular installation problems were foreseen.
DIRECT FLUSH TOILET VALVES
Direct flush toilet valves received the highest percentage (92%) of homeowner
approval of all the water saving devices. However, architect-engineers, plumbers,
and plumbing equipment manufacturers gave the direct flush valves a lower rating.
Noise and the requirements for higher water pressure or larger pipe sizes were the
main objections. Although many plumbers mentioned noise, only two of the 387
homeowners mentioned noise as a problem. The pressure or pipe size requirement
can be alleviated rather simply by increasing the pipe size. To some plumbers
and homeowners, the direct flush valves were considered to be preferable to the
tank type because of their dependability and waste flow reduction.
Toilets with Separate Flush Cycles for Urine and Feces
Toilets with separate flush cycles for urine and feces are a relatively new concept
in this country and its unfamiliarity was probably the cause for the lower percentages
favoring their use. Comments from plumbing equipment manufacturers indicated
that the major problems anticipated are more costly installation and maintenance
requirements. Also, they suggested that if it is difficult to change cycles, the cycle
using the most water will be used exclusively. One of the plumbers objected because
he felt that the reduced flush for urine would not properly cleanse the toilet bowl.
Homeowners also seemed to fear that a dual flush system would be difficult to use and
expensive to maintain. However, judging from some of the European designs and
their public acceptance, most of these objections appear unfounded and most objections
could be apparently removed by simple demonstrations and explanations.
HOME URINALS
Home urinals were considered objectionable by 63% of the homeowners, 23% of the
architect-engineers, 57% of the equipment manufacturers, and 76% of the plumbers.
The major objections stated were the extra cost and bathroom space required for the
urinal; however, the study by Kira (45) indicated that the major objections against the
use of urinals are actually psychological in origin and as a result household acceptance
will probably not be readily induced by practical and economic considerations.
The feasibility of this explanation is somewhat strengthened by the greater homeowner
approval of recycle toilets which are sanitarily, aesthetically, economically, and
operationally less acceptable than the urinal.
110
-------
RECYCLE TOILETS
Most survey participants objected to the household use of recycle toilets. The major
objections were the initial expense and the fear that unsanitary conditions would
develop. Handling the wastes when the holding tank is filled could be avoided by con-
necting the discharge directly to the sewer, but the problem of higher initial and
operating costs would remain, as would the possibility of odor if the device is not
properly maintained.
REUSE OF WASTE WASH WATERS
The reuse of waste wash waters appears to be generally acceptable to architect-
engineers and homeowners, although many questioned the degree of treatment to be
given the waste waters and some named specific limits to what they would accept.
For example, the water for toilet flushing must not appear dirty, be odorous, or
stain the toilet bowl and require more frequent cleaning; for irrigation water many
mentioned the necessity of removing soaps, bleaches, and other substances poten-
tially harmful to plants. One of the architect-engineers stated that he had already
designed wash water reuse systems for water short areas, and several others men-
tioned that they had designed systems using municipal aerobic treatment effluent.
INDIVIDUAL TREATMENT SYSTEMS
Of the 149 homeowners with individual treatment systems, 90% used a septic tank
and soil absorption system and 10% used a cesspool soil absorption system. In
most of the treatment systems (68%) the laundry and bathing waters are treated in
the same system as the sanitary wastes as suggested by the "Manual of Septic Tank
Practice" (90).
It was surprising to note that although 67% of the maintenance schedules reported by
the homeowners were inadequate according to recommendations in the Public Health
Service manual, only 40% experienced any recent need for service or repair and 60%
of those requiring service needed only routine removal of accumulated solids.
Generally, the homeowners and the architects seemed satisfied with the operation
of the septic tank soil absorption system. Apparently, this acceptance of the septic
tank system is based on satisfactory performance rather than merely low costs,
as the average costs reportedly allocated for individual sewage treatment by the
architect-engineers and which the homeowners indicated they would be willing to
pay were not low enough to encourage the use of unworkable systems. Only 40% of the
homeowners indicated desire for a more effective system and only 50% felt that even
a trouble-free system was worth more money. Many felt their present system was
already trouble-free.
Aerobic treatment systems were not used by any of the 387 homeowners responding
and only 17% of the architect-engineers had found it necessary or convenient to even
consider aerobic treatment rather than a septic tank. One architect said he had
installed several units which operated quite successfully, although the initial costs
were high.
Ill
-------
vm
CONCLUSIONS AND RECOMMENDATIONS
This report presents a useful composite of available waste treatment information
for individual households and introduces an area of household water and waste
management (waste prevention) which has previously received little attention in this
country. The conclusions of the study are presented below and then discussed along
with appropriate recommendations for additional activities.
CONCLUSIONS
Household Water Use
1. Quality requirements for specific household tasks can be safely lowered.
Many household tasks do not require water of drinking quality. Many of the
established standards are related to taste or odor, and water of lower quality
could be used for practically all purposes except those associated with
drinking or food preparation. Standards are suggested fbr bathing, general
cleaning, and toilet flushing. The practicality of using differing water
qualities for various tasks depends on the availability and cost of the
alternate water systems.
2. Household water usage can be significantly reduced.
There are many household functions in which water is used wastefully.
Water for bathing, toilet flushing, and laundry could be economically
reduced approximately 35% by use of presently available devices and tech-
nology. In a city of 100,000 these savings could amount to more than two
million gallons of water per day that would not have to be supplied to the
users and eventually treated in the waste treatment plant.
The reduction in household water use is an attractive and practical way
of aiding the fight against water and waste problems. Waste prevention
is one method of pollution control that will not become obsolete as new treat-
ment technology is developed. No matter what the method of treatment
either for large installations or for individual homes, handling and treatment
of the waste will be more efficient and less expensive when it is concentrated
in a smaller volume. For example, septic tank treatment efficiency depends
on the residence time of the sewage in the septic tank, a factor inversely
proportional to the waste flow to the system. The soil absorption system
will also perform more efficiently since the septic tank effluent will have
been more completely settled and treated, and the soil will have a greater
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opportunity to rest and regain infiltrative capacity because of the reduced
flow. Reduced flow would also enhance the performance of aerobic treatment
units by allowing longer periods for oxidation in the aeration chamber and
more efficient settling in the settling compartment.
Some manufacturers have anticipated the demand for plumbing devices that
use less water. Valves which restrict flow for faucets and showers, toilets
which use reduced flushing volumes, and washing machines which allow
just the required amount of water to be used are already available. A new
toilet with flushing quantities similar to the United Kingdom toilets has just
bean introduced (House and Home, April, 1969). Other innovations such
as the dual flush cycle toilet will probably be introduced in this country in
the near future.
3. A limited public opinion survey showed little opposition to the use of flow
reducing devices.
The survey of the homeowners, plumbers, architect-engineers, and equipment
manufacturers substantiated most of the opinions formed during the study and indicated
ready acceptance for all the water reduction devices except the home urinal and the
recycle toilets. The relatively good response to the survey showed that public
interest in protecting and preserving the environment is high. Most of the survey
participants seemed to favor the concept of flow reduction devices but were somewhat
hesitant to accept them in their own homes. Many of the architect-engineers and
plumbers seemed interested, but skeptical, and said they lacked data on most of the
devices.
In addition to the indication of which water reduction devices and techniques would be
most acceptable in the home, the survey showed the interest most people have in
reducing environmental pollution. An increasing number of people are aware of the
environmental pollution problems and of the economic and aesthetic effects that
these problems have on their own lives. In a national public opinion survey for the
National Wildlife Federation, George H. Gallup, Jr. reported that three of four
Americans from all income groups are willing to pay more taxes to improve their
natural environment (Air/Water Pollution Report, p. 72, March 3, 1969). In the
Niagara peninsula of Ontario, interested citizens have organized The Committee
of a Thousand, a group of dues-paying citizens who are personally involved in the effort
to discover and terminate all sources of pollution in their area (Watertalk, 1969).
Household Treatment and Possible Reuse
1. There is no simple solution to the problem of waste treatment for individual
households.
Individual household waste treatment will continue to be a problem in the
foreseeable future. Individual treatment units are being installed at a
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decreasing rate, but the numbers being installed and the number already in
use are very large. Household aerobic treatment units are presently the only
available alternative to the septic tank system and are practically competitive
with the septic tank only in areas of poor soil. Surface disposal of aerobic
effluents, which would help reduce aerobic treatment costs, cannot be recom-
mended without the provision of adequate safeguards to ensure an effluent that
will not endanger health or degrade the surrounding environment. Require-
ments for nutrient removal from effluents could further increase the cost of
disposing effluents to surface drainage.
The problem of individual household treatment will be of great importance for
many years and the development of a more efficient, more economical system
would be very profitable. The increasing population densities and the greater
demands for high quality recreational waters are making operation of in-
adequate individual treatment units more noticeable and objectionable.
Besides the need for better treatment, there is a need for better maintenance
of equipment and better understanding of the treatment process by the home-
owners. Many homeowners would give their treatment system proper care if
they had a better understanding of its operation. Information is available from
many government agencies, but builders, septic tank installers, and possibly
even an agency such as the Welcome Wagon could help to make sure all home-
owners with individual treatment systems had the necessary information.
2. Advanced waste treatment schemes other than simple filtration and disinfec-
tion are generally not practical for a normal household.
Most households could not meet the operating expenses or provide the
operating attention required by the majority of the advanced treatment systems.
Even when an extensively treated water is reused for all purposes but
drinking, the costs are prohibitive. The only economical and practical
reuse is the filtration and reuse of wash waters for toilet flushing, and in
areas where aerobic treatment is economical, the filtration and reuse of the
aerobic effluent for toilet flushing. Where possible, the reuse of wash waters
is preferable to the reuse of effluent from a septic tank or an aerobic treat-
ment unit. With wash waters the treatment is much simpler and the danger of
disease infection is more easily avoided.
While advanced waste treatment schemes do not seem generally practical
for individual home usage under the restrictions of present technology,
progress may depend on a single development which could occur at any time.
One of the advanced treatment techniques (oxidation by activated oxygen
produced through gamma radiation) which was considered unsuitable for
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household use earlier in this study has reportedly been developed as a
household treatment process (Chemical and Engineering News, p. 61,
April 21, 1969). A chemical treatment process, reportedly applicable for
households, is being tested at Washington State University. Changes in
treatment requirements and developments in other areas such as in auto-
matic controls could make other treatment systems acceptable in the house-
hold.
Similarly, developments which could make the advanced treatment processes
suitable for household use would make reuse schemes possible.
RECOMMENDATIONS FOR ADDITIONAL ACTIVITIES
Household Water Use
1. Studies on water quality and contaminant detection should be continued.
Although household water systems utilizing different levels of water quality
for different uses do not appear generally practical for the common house-
hold, more work should be sponsored in the area of water standards and
their measurement. The presence of many new chemicals which are difficult
to treat or remove and which may be dangerous in very small concentra-
tions is increasing the need for higher standards of water quality control.
The present level of waste recycling in many of the river systems as well
as a growing number of intentional reuses will intensify this need in the near
future. More knowledge is needed on the effect of many chemicals and the
means of detecting and removing those chemicals which may be found
harmful.
2. Flow reduction concepts should be more extensively promoted and publicized.
Many persons contacted in the public opinion survey, including many
plumbers and architect engineers, had not heard of the various flow reduc-
tion devices and had received no information on them. Manufacturers
should provide the architect-engineers and plumbers with factual information
on the design, operation, and cost of these items as well as data on the
potential savings available to customers and to society in the form of better
water and waste management. It would also be advantageous for the manu-
facturers to directly contact large businesses, industries, and public
institutions where many water and waste systems are often concentrated
in one or two locations and where additional per unit savings are possible
in material and labor costs.
An impartial demonstration of the use and water saving capabilities of these
water reduction devices would also be very beneficial in securing public
support and in providing data which could be used for design purposes as
these devices become more common. At first, it might seem that such a
study would be redundant in that equipment manufacturers probably already
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have extensive data on the operation of the particular device which they
market. However, household usage does not always correspond to the
manufacturers' criteria; nor do homeowners always use equipment exactly
as directed. The proposed evaluation should not only reveal possible
difficulties, but more importantly, provide data for typical costs (installation,
maintenance, repair, etc.) and typical savings in water and fuel that could
be expected in a normal home. Such information would be very useful to
architect-engineers, plumbers, homeowners, and the equipment manu-
facturers themselves. It would also provide the data for an analysis of any
conflicts with local plumbing codes and where necessary should provide
adequate data for changes in antiquated legislation.
In the first phase of the recommended study, a representative group of
families should be chosen for the tests and their present water using system
thoroughly surveyed as to the frequency of usage and the amount of water
used in each of the household functions. For the second phase of the study
the flow reducing devices would be installed and the same data would be
recorded. In addition,the reactions of the families to the use of these
devices would be carefully examined.
3. The use of community schemes for more efficient water and waste handling
should be further investigated.
Waste collection and water distribution systems must be studied on a
community, rather than an individual, basis. Two potentially lower cost
waste collection systems have been proposed; both systems, a pressure
system and a vacuum system, allow smaller diameter waste lines and
eliminate the need for the excessively deep trenches required with gravity
sewers. In the pressure system, the sewage is ground and pumped through
a check valve from each household into small diameter pressurized sewer
lines. In the vacuum system wastes are transported from specially designed
water closets by a central vacuum system. This system has the added
advantage of using only a tenth as much flushing water. Each system
requires special equipment in the household and each would therefore re-
quire some additional maintenance. Potentially these schemes could
substantially reduce the cost of sewer lines and, for the vacuum system,
reduce water requirements; but more information is needed before either of
these systems or a combination of the two can be recommended. Con-
sideration must also be given to the effect such changes would have on the
water system, the waste treatment system, and on other utilities such as
power.
Household Treatment and Reuse
1. Additional studies should be conducted to clarify the effect of a higher
quality sewage effluent on a soil absorption system.
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Previous studies have not clearly substantiated claims for a greater soil
absorption capacity with aerobic effluents. Further information is needed
to permit effective regulation of the soil absorption systems for aerobic
treatment.
2. Criteria for the design, construction, operation, and effluent quality of
household treatment systems must be developed before the surface discharge
of treated effluents can be permitted.
Individual household treatment systems are administered primarily by local
officials who often do not have the background to adequately check individual
household systems without the aid of such detailed criteria. The criteria
developed should be general enough to apply throughout the country and to all
types of treatment systems and should include provisions requiring safe-
guards to prevent the discharge of inadequately treated effluent.
3. Research on improved individual waste treatment systems should be
continued.
The large number of homes depending on individual treatment systems, and
the sometimes less than adequate service of available treatment units insure
a ready market for an improved treatment system, whether it is a com-
pletely new system or a modification of existing systems. Because of the
septic tank's low maintenance and generally acceptable service, further
improvement of septic tank design would seem a logical starting place.
Most present designs have been related more closely to construction ease
than to treatment efficiency, but new materials and new fabrication tech-
niques may permit designs that encourage higher treatment efficiency and
better maintenance. As an example, one possible design change which would
theoretically improve septic tank digestion and solids removal would be the
combination of the principles of the anaerobic contact process and the
anaerobic filter (105). Improvement of aerobic treatment systems and the
development of entirely new concepts should also be encouraged. Poten-
tially the aerobic treatment units can provide better waste treatment than
anaerobic units; however, safety requirements indicate that subsurface
filters are still desirable. The development of controls to economically
monitor and control the effluent quality would encourage acceptance of aerobic
treatment units with surface disposal.
4. An effort should be made to channel the high public interest in environmental
protection into constructive public action.
One possibility for extending and exploiting present public interest, would be
an effort to involve youth organizations in the program to combat deteriora-
tion of the environment. Many youth organizations, especially those like
scouting with many outdoor activities, should welcome and actively support
programs to cleanse and protect our polluted land and water resources.
The ideas and practices fostered by such activities could also stimulate
interest and activity in the adult segment of the population.
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REFERENCES CITED IN THE TEXT
1. Advanced Waste Treatment Research Basic & Applied Sciences Branch,
Division of Water Supply and Pollution Control. Summary Report, The
Advanced Waste Treatment Research Program, January 1962-June 1964.
P.H.S. Publ. No. 999-WP-24, 1965.
2. Advanced Waste Treatment Research, Federal Water Pollution Control
Administration. Summary Report, Advanced Waste Treatment, July 1964-
July 1967. FWPCA Publication No. WP-20-AWTR-19, 1968.
3. Anderson, J. S. and Watson, K. S. "Patterns of Household Usage", Journal
American Water Works Association. Vol. 59, No. 10, Part 1, October 1967.
4. Badger, W. L. and Associates, "A Study of the Processes for the Production of
Potable Water from Aqueous Wastes Developed in a Shelter." Report prepared
for the Office of Civil Defense under Contract No. OCD OS 62-120, October
1962.
5. Barry, J. P., Bishop, H. K., and Outer, G. A., "Development of Design
Criteria for an Electrochemical Water Reclamation System", prepared for
Langley Research Center, NASA, August 1968.
6. Belasco, N. and Perry, D. M., "Waste Management and Personal Hygiene
for Extended Space Craft Missions", paper presented to the American Industrial
Hygiene Conference in Philadephia, Pa., April 1964.
7. Bell, G. S., "Residential Use and Misuse of Sanitary Sewers", JWPCF Vol. 35,
No. 1, January 1963.
8. Bendixen, T. W. Individual Sewage Disposal Systems. Robert A. Taft Sanitary
Engineering Center, November 1959.
9. Bendixen, T. W. and Weibel, S. R., Study on Septic Tanks and Septic Tank
Disposal Systems. Agricultural Engineering, Vol. 32, No. 9, p. 449,
September 1951.
10. Bialecki, A., Blecharzyk, S., and Oetken, E. R., "Progress on Saline
Water Demineralization and Evaluation of the Hickman Still", General
Dynamics Internal Report, 1957.
11. Brown, D. L., Lindstrom, R. W., and Smith, J. D., The Recovery of Water
From Urine by Membrane Electrodialysis. AMRL-TDR-63-30, April 1963.
12. Campbell, L. A., Director Dept. of Applied Microbiology, Ontario Research
Foundation, Ontario, Canada. Letter to V. T. Boatwright, Jr., September
1968.
118
-------
REFERENCES CITED IN THE TEXT (Cont'd)
13. Campbell, L. A., "A Feasibility Study of a Completely Recycled Water System
in an Apartment Complex with a Population of 1,000 People." Report AM-6803
for Central Mortgage and Housing Corporation, March 1968.
14. Campbell, L. A., and Smith, D. K., "The Use of Water Within a Single House-
hold, Canadian Municipal Utilities, February 1964.
15. Campbell, L. A. and Smith, D. K., "An Investigation of Individual House-
hold Aerobic Sewage Treatment Units", Canadian Municipal Utilities, November-
December 1963.
16. Clark, C. M., and Watson, K. S., "Garbage Grinders Add Only 30%", The
American City, June 1962.
17. Clark, J. W., and Viessman, W., Jr., Water Supply and Pollution Control,
International Textbook Company, Scranton, Pennsylvania, 575 pp.
18. Committee on Public Health Activities of the Sanitary Engineering Division,
"A Study of Sewage Collection and Disposal in Fringe Areas", Journal of the
Sanitary Engineering Division, Proceedings of the American Society of Civil
Engineers. Paper 1613, Paper 1686, April 1958, and June 1958, respectively.
19. Cougan, G. J., Rosenthal, B. L., and O'Brien, J. E., "Aerobic Treatment
of Household Wastes", Department of Public Health Experiment Station Report,
February 1962.
20. Coulter, J. B., "Notes on the Use of Septic Tank Soil Absorption Systems",
presented at the 1958 Home Sewage Disposal Conference, Michigan State
University, January 1958.
21. Coulter, J. B., "The Septic Tank System in Suburbia", Public Heajth Reports,
Vol. 73, No. 6, June 1958.
22. Coulter, J. B., Bendixen, T. W., "Serial Distribution, An Improved Design
for the Septic Tank", Robert A. Taft Sanitary Engineering Center, October
1958.
23. Coulter, J. B., Bendixen, T. W., "Sewage Treatment Plants for the Suburban
Sewerage System" paper presented at Iowa Sewage and Industrial Wastes Associa-
tion Meeting, June 1960.
24. Coulter, J. B., Bendixen, T. W., and Thomas, H. A., Jr. "Metropolitanism
and Sewage Handling Technology, Sewage and Industrial Wastes, p. 900,
August 1959.
25. Crisp, J. and Sobolev, A., "Water and Fuel Economy - The Use of Spray
Taps for Ablutions in Buildings", Journal of the Royal Institute of British
Architects, July 1950.
119
-------
REFERENCES CITED IN THE TEXT (Cont'd)
26. Crisp, J. and Sobolev, A., "An Investigation of the Performance of Lavatories
Using Spray-Taps and of Sanitary Accommodation in an Office Building",
Reprint of Article from Journal of Institution of Water Engineers, 1959.
Vol. 13, pp. 513-525.
27. Gulp, G. L., "High Rate Clarification of Waste Waters", paper presented at
the University of Kansas Sanitary Engineering Conference, January 1968.
28. Dague, R. R., McKinney, R. E., and Pfeffer, J. T., "Anaerobic Activated
Sludge", JWPCF, Vol. 38, No. 2, February 1966.
29. Degen, R. A., "Product Manager Brass Fittings", Kohler Co., Kohler,
Wisconsin". Letter to J. L. Dodson, General Dynamics, Electric Boat
division, August 7, 1968.
30. Dorn, J. E., "Product Safety Director", Frigidaire Div. of General Motors
Corp., Dayton, Ohio 45401, Letter to J. L. Dodson, July 31, 1968.
31. Duncan, D. L., "Individual Household Recirculating Waste Disposal System
for Rural Alaska", JWPCF, Vol. 36, No. 12, December 1964.
32. Esten, H., Murray, R. W., and Cooper, L., "Vacuum Distillation, Vapor
Pyrolysis Water Recovery System Utilizing Radioisotopes for Thermal
Energy", AMRL-TR-67-80, WPAFB, November 1967.
33. Flaherty, W. F., "The Effect of Water Reuse on Water Quality", Water
and Sewage Works, 114:8 354-357, August 1968.
34. Fox, J. J., Engineering Manager, Laundry Equipment Division, Westing-
house Electric Corp., 146 E. 4thLSt., Mansfield, Ohio 44901. Letter to
J. L. Dodson, October 11, 1968.
35. Fpyn, E., "Removal of Sewage Nutrients by Electolytic Treatment", Verh.
Internat. Verein. Limnol., XV, 569-579, February 1964.
36. Garthe, E. C., and Gilbert, W. C., "Wastewater Reuse at the Grand Canyon",
JWPCF, Vol. 40, No. 9, p. 1582, September 1968.
37. Geinopolos, A., Wullschleger, R. E., and Mason, D. G., "Engineering
Design Study for the Development of a Self-Contained, Air-Transportable
Wastewater Treatment Prototype (U)", report prepared for the U. S. Army
Mobility Equipment Research and Development Center, Ft. Belvoir,
Virginia, February 1968.
38. Hall, E. P. (Chairman Committee on Water Pollution from the Operation of
Vessels), Wastes from Watercraft, A Report to the Congress, U. S. Dept.
of the Interior, June 1967.
120
-------
REFERENCES CITED IN THE TEXT (Cont'd)
39. Haney, P. D. and Hamann, C. L., "Dual Water Systems", JAWWA, Vol.
57, No. 9, p. 1073, September 1965.
40. Hanna, G. P., Jr. and Shumate, K. S., "Evaluation of Effects of Enzyme
Products on Overloaded Anaerobic Digestion Systems", Final Report to Rohm
& Haas Company, April 1966.
41. Harrison, F. E., Managing Director, Cisterns Limited Addingham, nkley,
Yorks, U. K., Letter to V. T. Boatwright Jr., September 1968.
42. Hill, R. D., Schwab, G. Q., Maleney, G. W., and Weiser, H. H.,
"Filtration and Disinfection of Farm Pond Water", Research Bulletin 966,
Ohio Agricultural Experiment Station, August 1964.
43. Jackson, J. K., Bonura, M. L., and Putnam, D. F., "Evaluation of a Closed
Life-Support System During a 60-Day Manned Test", paper presented to 1968
S. A. E., Aeronautic and Space Engineering Meeting at Los Angeles, California,
October 1968.
44. Kinney, E. T., and Singerman, H. H., "The Navy's Technological Progress
in Water Pollution Abatement", Fifth Annual Technical Symposium, Naval
Ship Systems Command.
45. Kira, A., "The Bathroom, Criteria for Design", Research Report No. 7,
Center for Housing and Environmental Studies, Cornell University, 1966.
46. Knight, B. M., General Manager, Richard Fife, Inc., 1140 Broadway, New
York, N. Y. 10001, Letter to J. L. Dodson, General Dynamics, Electric Boat
division, October 17, 1968.
47. Kolega, J. J., Wheeler, W. C., and Hawkins, G. W., Jr., "Current Septic
Tank System Installation Practices in Connecticut", JWPCF, Vol. 38, No.
10, October 1966.
48. Kolnsberg, H. J., and Dudarevitch, M. D., "Water Reclamation by
Membrane Vapor Diffusion", Transactions of the ASME Journal of Engineering
for Industry, November 1968.
49. Linaweaver, F. P., Jr., "Report on Phase One, Residential Water Use
Research Project", The Johns Hopkins University, Dept. of Sanitary Engi-
neering, October 1963.
50. Ling, J. T., "Pilot Study of Treating Chemical Wastes With an Aerated
Lagoon", JWPCF, Vol. 35, No. 8, p. 963, August 1963.
51. Ludwig, H. F., and Stewart, J., "Equilibrium Percolation Test for Estimating
Soil Leaching Capacity", paper presented at the San Francisco National Meeting
of the APHA, October 29-November 2, 1951.
121
-------
REFERENCES CITED IN THE TEXT (Cont'd)
52. Mason, D. G., "Engineering Evaluation of Reverse Osmosis and Ion Exchange
Demineralization for Use in a Self-Contained, Air-Transportable Waste Water
Renovation Unit (U)", Report prepared for U. S. Army Mobility Equipment
Research and Development Center, Ft. Belvoir, Virginia, July 1968.
53. McGauhey, P. H. and Winneberger, J. H., "Studies of the Failure of Septic
Tank Percolation Systems", Journal Water Pollution Control Federation,
Vol. 36, p. 593, 1964.
54. McKee, J. E., and Wolf, H. W., Water Quality Criteria. Second Edition.
Resources Agency of California, State Water Quality Control Board Publica-
tion 3-A, 548 pp., 1963.
55. Mclaughlin, E. R., A Recycle System for Conservation of Water in Residences.
Water & Sewage Works 115:4, April 1968, 175-176.
56. McNeil, W., "Urine Evaporator", USAF Aero Medical Laboratory, Wright
Air Development Center, Technical Report No. 54-94, February 1954.
57. Michaels, A., Membranes, the Thin Difference. Industrial Research, April
1969, p. 48.
58. Miller, H. C., and Knipe, W., "Electrochemical Treatment of Municipal
Waste Water", P.H.S. Publication No. 999-WP-19, 1965.
59. Morris, J. C., "Conventional Approaches Not Enough", Chemical Engineering
Progress, Vol. 59, No. 4, November 1963.
60. National Academy of Sciences - National Research Council, Report on In-
dividual Household Aerobic Sewage Treatment Systems, Publication 586,
February 1958.
61. National Association of Home Builders, "Economic News Notes", Housing
Starts Bulletin, September 17, 1968.
62. Office of Saline Water, U. S. Department of the Interior, "1966 Saline Water
Conversion Report", 1966.
63. Office of Saline Water, U. S. Department of the Interior, "1967 Saline Water
Conversion Report".
64. Ohio State University Engineering Experiment Station, "A 23-Month Study of
Individual Household Aerobic Sewage Treatment Systems", July 1961.
65. Okey, R. W., and Stavenger, P. L., "Industrial Waste Treatment with
Ultrafiltration Processes", Paper Presented to Symposium on Membrane
Processes for Industry, Sponsored by the Southern Research Institute at
Birmingham, Alabama in May 1966.
122
-------
REFERENCES CITED IN THE TEXT (Cont'd)
65A. Olsson, E., Karlgren, L., and Tullander, V., "Household Waste Water",
The National Swedish Institute for Building Research, Report 24: 1968.
66. Parker, U. R., Installation Engr., Sloan Valve Co., 4300 West Lake Street,
Chicago, HI. 60624, Letter to J. L. Dodson, July 26, 1968.
67. Pecis, J. C., Vice President Research & Development, Speakman Co.,
Wilmington, Delaware 14899, Letter to J. L. Dodson, General Dynamics,
Electric Boat division, July 22, 1968.
68. Popkiu, R. A., and Bendixen, T. W., "Improved Subsurface Disposal",
JWPCF, Vol. 40, No. 8, Part 1, August 1968.
69. Popma, D. C., and Collins, V. G., "Space Vehicle Water Reclamation
Systems", paper presented at the 55th National Meeting of the American
Institute of Chemical Engineers, Houston, Texas, February 1965.
70. Preul, H. C., "Underground Movement of Nitrogen", JWPCF, Vol. 38, No. 3,
March 1966.
71. Public Health Service, "Public Health Service Drinking Water Standards".
Revised 1962. U. W. Department of Health, Education and Welfare; Public
Health Service, Washington 25, D. C. Public Health Service Publication No.
956, 1962.
72. Ranum, J. M., Executive Director, Corporate Public Affairs, Whirlpool
Corp., Benton Harbor, Michigan 49022, Letter to J. L. Dodson, September
11, 1968.
73. Reid, G. W., "Projection of Future Municipal Water Requirements", South-
west Water Works S. 46:18, 1965.
74. Robeck, G. G., Cohen, J. M., Sayers, W. T., and Woodard, R. L.,
"Degradation of ABS and other Organics in Unsaturated Soil", JWPCF,
Vol. 35, No. 10, p. 1225, October 1963.
75. Scott, J. A., "Health Considerations Involved in the Treatment and Disposal
of Sewage from Isolated Dwellings", The Sanitarian, December 1952.
76. Slonim, A. R., Hallam, A. P., Jensen, D. H., and Kammermeyer, K.,
"Water Recovery from Physiological Sources for Space Applications", Life
Support Systems Laboratory, Wright-Patter son Airforce Base, Ohio, July 1962
77. Smith, R., "Cost of Conventional and Advanced Treatment of Wastewaters",
JWPCF, Vol. 40, No. 9, September 1968.
78. Sobolev, A., Building Research Station, Garsten, Watford, Herts. U.K.,
"Spray Traps", Reprint of Paper Published in Heating, Vol. 22, 1960.
123
-------
REFERENCES CITED IN THE TEXT (Cont'd)
79. Sobolev, A., and Lloyd, C. J., Building Research Station, Garsten,
Watford, Herts, U. K., "Trials of Dual Flush Cisterns", Reprint from Journal
of Institution of Water Engineers, Vol. 18, No. 1, February 1964.
80. Steele, James A., "Waste Management System Evaluation for Space Flights
of One Year Duration", Report Prepared by General Dynamics/Astronautics
for Langley Research Center, Hampton, Va., Contract NAS1-2934, October 1963.
81. Steele, J. A., Lubitz, J. A., Wallman, H., Benoit, R. J., Speziali, V. A.,
and Bolles, T. V., "A Study of Water Reclamation Systems for Space Stations",
Research and Development Department, General Dynamics, Electric Boat
division, Groton, Connecticut, Dec ember 31, 1962.
82. Steele, J. A., Lubitz, J. A., Wallman, H., Miner, H., and Speziali, V.,
"Water Reclamation Subsystems for Space Stations", Contract NAS 1-2208,
July 1963.
83. Stevens, D. B., "Wastewater Reuse", JWPCF 40-4-677-683, April 1968.
84. Stevens, D. B., and Peters, J. H., "Long Island Recharge Studies", JWPCF
38:12, 2009, December 1966.
85. Technical Report No. LWT-68-1, "The Development, Design and Performance
of Model No. 1100-10", Met-Pro Water Treatment Corporation, 1968.
86. Thomas, R. E., and Bendixen, T. W., "Domestic Water Use in Suburban
Homes", Final Report to the Federal Housing Administration by the Robert
A. Taft Sanitary Engineering Center, June 1962.
87. Thomas, H. A., Jr., Coulter, J. B., Bendixen, T. W., and Edwards, A. B.,
"Technology and Economics of Household Sewage Disposal Systems", JWPCF,
Vol. 32, No. 2, February 1960.
88. U. S. Department of Commerce, Bureau of the Census, "Statistical Abstract
of the United States", 1968. 80th Edition.
89. U. S. Department of Commerce, Bureau of the Census, "1960 U. S. Housing
Census, Volume I".
90. U. S. Department of Health, Education, and Welfare, "Manual of Septic-Tank
Practice", Public Health Service Publication No. 526, 1967.
91. U. S. Department of Health, Education, and Welfare, "Septic Tank Care",
Public Health Service Publication No. 73, 1967.
92. U. S. Department of the Interior, Federal Water Pollution Control Administra-
tion, "Problems of Combined Sewer Facilities and Overflows 1967", WP-20-11.
124
-------
REFERENCES CITED IN THE TEXT (Cont'd)
93. Wallman, H., and Barnett, S. M., "Water Recovery Systems (Multi-Variable)",
Prepared by General Dynamics Corporation for the Aerospace Medical
Laboratory at Wright-Patter son Air Force Base under Contract AF 33 (616) -
6425, 1959.
94. Wallman, H., Steele, J. A., and Lubitz, J. A., "Multi-Filter System for
Water Reclamation", Aerospace Medicine, Vol. 36, No. 1, January 1965.
95. Water Quality Criteria, "Report of the National Technical Advisory Committee
to the Secretary of the Interior", 234 pp. April 1, 1968. Federal Water Pollu-
tion Control Administration, Washington, D. C.
96. Watson, K. S., "Water Requirements of Dishwashers and Food Waste Dis-
posers", Journal American Water Works Association, Vol. 55, No. 5,
May 1963.
97. Watson, K. S., Farrell, R. P., Anderson, J. S., "Contribution from the
Individual Home to the Sewer System", JWPCF 39:12, 2039-2054, December
1967.
98. Wheaton, R. B., Brown, J. R. C., Ramirez, R. V., and Roth, N. G.,
"Investigation of the Feasibility of Wet Oxidation for Space Craft Waste
Treatment", Report Prepared for National Aeronautics and Space Administra-
tion under Contract NAS 1-6295, by Whirlpool Corporation, 1966.
99. Williams, R. W., Manager Product Planning, American Std. Plumbing &
Heating Division, 40 West 40th Street, New York, N. Y. 10018. Letter and
phone conversation, July 29, 1968, to J. L. Dodson.
100. Winneberger, J. H., Francis, L., Klein, S. A., and McGauhey, P. H.,
"A Study of Methods of Preventing Failure of Septic-Tank Percolation Fields,
Fourth Annual Report", Sanitary Engineering Research Laboratory, University
of California, Berkeley, August 1960.
101. Winneberger, J. H., and McGauhey, P. H., "A Study of Methods of
Preventing Failure of Septic-Tank Percolation Fields, Fourth Annual Report",
Sanitary Engineering Research Laboratory, University of California, Berkeley,
SERL Report No. 65-16, October 1965.
102. Winneberger, J. H., Menar, A. B., and McGauhey, P. H., "A Study of
Methods of Preventing Failure of Septic-Tank Percolation Fields, Third
Annual Report", Sanitary Engineering Research Laboratory, University of
California, Berkeley, SERL Report No. 63-9, December 1963.
103. Witchger, E. S., Director Special Projects, Elger Plumbingware Div.,
Wallace Murray Corp., 650 Washington Rd., Pittsburgh, Pa. 15228. Letter
to H. Wallman, October 21, 1968.
125
-------
REFERENCES CITED IN THE TEXT (Conf u,
104. Witherow, J. L., Coulter, J. B., and Ettinger, M. B., "Suburban Sewage
Treatment by the Anaerobic Contact Process", Robert A. Taft Sanitary
Engineering Center, December, 1957.
105. Young, J. C., and McCarty, P. L., "The Anaerobic Filter for Waste
Treatment", JWPCF, Vol. 41, No. 5, Part 2, May 1969.
106. Zeff, J. D., and Bambenek, R. A., "Development of a Unit for Recovery of
Water and Disposal or Storage of Solids from Human Wastes", American
Machine and Foundry Company Contract No. AF 33(616)-5783, January 1959.
107. Zeitoun, M. A., Davison, R. R., White, F. B., and Hood, D. W., "Solvent
Extraction of Secondary Wastewater Effluents: Heterogeneous Equilibrium of
Organic and Inorganic Compounds", JWPCF, Vol. 38, No. 4, April 1966.
108. Ziemke, N. R., and Allen, G. S., "Functional Testing Reports, The Armon
System", Tests by Sanitary Engineering Research Company, 1966.
126
-------
ADDITIONAL REFERENCES
Ames Research Center, "The Closed Life-Support System", report prepared by
National Aeronautics and Space Administration, April 1966.
Aquatic Life Advisory Committee of the Ohio River Valley Water Sanitation Com-
mission, "Aquatic Life Water Quality Criteria", JWPCF - Vol. 32, No. 1, January
1960.
Baffa, J. J., and Bartilucci, N. J., "Waste Water Reclamation by Ground Water
Recharge on Long Island", JWPCF Vol. 39, No. 3, March 1967.
i
Barduhn, A. J., "Where Do the Chemical Engineers Come In?", Chemical Engineering
Progress, Vol. 59, No. 11, November 1963.
Bendixen, T. W., Thomas, R. E., and Coulter, J. B., "Study of Seepage Pits",
Robert A. Taft Sanitary Engineering Center, May 1963.
Clark, B. D., "Houseboat Wastes, Methods for Collection and Treatment", Federal
Water Pollution Control Administration, June 1967.
Coulter, J. B., and Bendixen, T. W., "A Study of Serial Distribution for Soil
Absorption Systems", Robert A. Taft Sanitary Engineering Center, April 1959.
Committee on Rural Sanitation, "Rural Sanitation", American Journal of Public
Health, Vol. 30, No. 5, May 1949.
Coulter, J. B., Bendixen, T. W., and Edwards, A. B., "Study of Seepage Beds
Part I", Robert A. Taft Sanitary Engineering Center, February 1960.
Coulter, J. B., and Bendixen, T. W., "Report to Federal Housing Administration
on Study to Determine if Distribution Boxes can be Eliminated Without Inducing
Increased Failure of Disposal Fields", Robert A. Taft Sanitary Engineering Center.
Coulter, J. B., "Limitations on the Use of Septic Tank Systems", Robert A. Taft
Sanitary Engineering Center.
Coulter, J. B., Bendixen, T. W., and Edwards, A. B., "Study of Seepage Beds",
Report to the Federal Housing Administration by the Robert A. Taft Sanitary
Engineering Center, December 1960.
Coulter, J. B., "Sewage Disposal Systems Applicable to Subdivisions", paper
presented to National Association of Home Builders Convention - Exposition at Chicago,
Illinois, January 1957.
Coulter, J. B., Soneda, S., and Ettinger, M. B., "Preliminary Studies on
Complete Anaerobic Sewage Treatment", Journal of the Sanitary Engineering Division.
Proceedings of the American Society of Civil Engineers. Proceedings Paper 1089,
March 1957.
127
-------
ADDITIONAL REFERENCES (Cont'd)
Coulter, J. B., Bendixen, T. W., and Edwards, A. B., "Study of Seepage Beds,
Part H", Robert A. Taft Sanitary Engineering Center, May 1960.
Eastman, "Municipal Wastewater Reuse for Irrigation", Journal of the Irrigation
and Drainage Division, Proceedings of the American Society of Civil Engineers
93:IR3, 25 (1967).
Evans, D. M., "Man-made Earthquakes in Denver", Geotimes 10:9, 11-18,
May-June 1966.
Federal Water Pollution Control Administration, U. S. Dept. of the Interior, The
Cost of Clean Water. October 1967.
Gallagher, E., "Water Reuse as a Method of Water Supply and Pollution Reduction",
Water and Sewage Works, August 1968, p. 356.
General Atomic Division of General Dynamics, "Reverse Osmosis for Waste Water
Treatment", March 1967.
Gerster, J. A., "Cost of Purifying Municipal Waste Waters by Distillation",
prepared for The Advanced Waste Treatment Research Program. U. S. Dept. of
Health, Education, and Welfare, November 1963.
Hickey, J. L. S., and Duncan, D. L., "Performance of Single Family Septic Tank
Systems in Alaska", JWPCF, Vol. 38, No. 8, August 1966.
Hickman, K. C., "A Study of Distillation Processes for Potable Water Recovery and
Residue Disposal", paper presented at the seminar on Advanced Waste Treatment
Research in Cincinnati, Ohio, May 1962.
Horowitz, H., "The Effect of Automatic-Sequence Clothes Washing Machines on
Individual Sewage Disposal Systems", Report No. 5 to the Federal Housing Ad-
ministration by the Building Research Advisory Board. National Academy of
Sciences - National Council Publication 442, March 1956.
Hydo, C. G., "The Beautification and Irrigation of Golden Gate Park with Activated
Sludge Effluent", Sewage Works Journal, Volume 9, No. 6, November 1937.
Ihglefinger, A. L., Secord, L. C., and Arndt, W. F., "Life Support System
Manned Testing with Oxygen and Water Recovery". McDonnell Douglas Corporation.
Ingram, W. T., Cardenas, R., Broglie, J., and Slate, L., "Space Capsule Waste
Treatment and Potable Water Recovery", Journal Water Pollution Control Federation,
p. 38, January 1964.
Jones, J. H., and Taylor, G. S., "Septic Tank Effluent Percolation Through Sands
Under Laboratory Conditions", Soil Science, Vol. 99, No, 5.
128
-------
ADDITIONAL REFERENCES (Cont'd)
Ledbetter, J. O., "Can We Afford Zero Health Risks", Water and Sewage Works,
Vol. 115, No. 9, p. 438, September 1968.
LeGrand, H. E., "A Broad View of Waste Disposal in the Ground", Water and
Sewage Works, Vol. 114, R. N., P. R-179.
LeGrand, H. E., "Management Aspects of Ground Water Contamination", JWPCF,
Vol. 36, No. 9, September 1964.
Lubitz, J. A., Benoit, R. J., Wallman, H., and Adamson, T. E., "Wash Water
Reclamation for Extended Duration Space Voyages", paper presented at 1st American
Institute of Aeronautics and Astronautics Annual Meeting at Washington, D. C., June
1964.
Mattson, R. J., and Tomsic, V. S., "Improved Water Quality", Chemical Engi-
neering Progress, Vol. 65, No. 1, January 1969.
McGauhey, P. H., and Winneberger, J. H., "A Study of Methods of Preventing
Failure of Septic Tank Percolation Systems", booklet published by Department of
Housing and Urban Development, Federal Housing Administration, October 1967.
McKee, J. E., "Reclaimed Sewage Water Socially Okay", Environmental Science
and Technology, Vol. 3, No. 1, January 1969.
McMahan, A. A., and Bendixen, T. W., "Report to the Federal Housing Administra-
tion on the Frequency of Occurrence of Water-Using Appliances in Suburban Homes
Having Individual Sewage Disposal Systems", March 1961.
Merten, U., "Reverse Osmosis", General Atomic Division of General Dynamics,
May 1965.
Merten, U., Nusbaum, I., and Miele, R., "Organic Removal by Reverse Osmosis",
paper presented at the American Chemical Society Symposium on Organic Residue Re-
moval from Waste Waters, September 1968, Atlantic City, N. J.
Metzger, C. A., Hearld, A. B., and McMullen, B. G., "Water Recovery from
Human Waste During Prolonged Confinement in the Life Support System Evaluator",
Aerospace Medical Research Laboratory, Wright-Patterson Air Force Base, Ohio,
April 1966.
Metzger, C. A., Hearld, A. B., and McMullen, B. G., "Evaluation of Water
Reclamation Systems and Analysis of Recovered Water for Human Consumption",
AMRL-TR-66-137 WPAFB, February 1967.
Michaels, A. S., "New Separation Technique for the C. P. I. ", Chemical Engineering
Progress, Vol. 64, No. 12, December 1968.
National Academy of Sciences, National Research Council, "Alternatives in Water
Management", 1966.
129
-------
ADDITIONAL REFERENCES (Cont'd)
Neale, J. H., "Advanced Waste Treatment by Distillation", report for the Advanced
Waste Treatment Research Program, U. S. Dept. of Health, Education, and Welfare,
March 1964.
Nichols, D. C., "Water Reclamation from Urine Thermoelectric System", AMRL-
TR-65-29, WPAFB, March 1965.
Nuccio, P. P., and Jasionowski, W. J., "Automatic Water Recovery System",
AMRL-TR-67-155, WPAFB, March 1968.
Oakley, H. R., and Cripps, T., "British Practice in the Treatment of Waste Water",
JWPCF, Vol. 41, No. 1, January 1969.
Pecoraro, J. R., Pearson, A. O., Drake, G. L., and Burnett, J. R., "Contributions
of a Developmental Integrated Life Support System to Aerospace Technology", paper
presented at American Institute of Aeronautics and Astronautics, 4th Annual Meeting
and Technical Display at Anaheim, California, October 1967.
Porges, R., and Morris, G. L., "Extended Aeration Sewage Treatment, A Pre-
liminary Evaluation", publication of the U. S. Public Health Service, Robert A.
Taft Sanitary Engineering Center 1960.
Robeck, G. G., Bendixen, T. W., Swartz, W. A., and Woodward, R. L., "Factors
Influencing the Design and Operation of Soil Systems for Waste Treatment",
JWPCF, Vol. 36, No. 8, August 1964.
Ryan, M. J., and Edgerley, E., "Water Recovery from Human Liquid Wastes by
Distillation and Chemical Oxidation", USAF School of Aerospace Medicine, Brooks
Air Force Base, Texas, December 1967,
Slonim, A. R., "Rapid Procedures to Monitor Water for Potability", Aerospace
Medicine, Vol. 39, No. 11, November 1968.
Stanford Research Institute, "Long Range Planning Report: "Water", Report No.
16, September 1959.
Stephan, D. G., and Weinberger, L. W., "Waste Water Reuse Has It 'Arrived1",
paper presented at 40th Annual Conference of the Water Pollution Control Federation,
New York, N. Y., October 1967.
Stevens, D. B., "Wastewater Reuse, Status in New York State", paper presented
at the 40th Annual Meeting of the Water Pollution Control Federation in New York
City, N. Y., October 1967.
Sudak, R. G., and Nusbaum, I., "Pilot Plant Operation of Spiral Wound Reverse
Osmosis Systems", paper presented at the Western Water and Power Symposium,
April 1968, at Los Angeles, Calif.
130
-------
Table A-l. Waste Treatment Manufacturers*
Manufacturer Contacted
Location
1. Fifer Industries Inc. Louisville, Ky.
2. DuPont Wilmington, Del.
3. Gulf General Atomic San Diego, Calif.
4. Hamilton Southern Assn. Hickory, N. C.
5. Jet Aeration Co.
6. Valdespino Labs
7. Dorr Oliver
8. Rex Chain Belt
9. Yeomans
10. General Electric Co.
11. Cromaglass Corp.
12. Converto Co.
13. Wilson Water Purif.
Company
14. BK>2 Systems Inc.
15. Svenska Interpur Ab
16. Allenaire, Inc.
17. Convert-All, Inc.
18. Microphor, Inc.
19. Sewerless Toilet Co.
Cleveland, Ohio
Orlando, Fla.
Stamford, Conn.
Milwaukee, Wis.
Melrose Park, HI.
Schenectady, N. Y.
Williamsport, Pa.
Montreal, P. Q.
Buffalo, N. Y.
Kansas City, Mo.
Stockholm, Sweden
Warren, Ohio
Brunswick, Maine
Willits, Calif.
Type Process
"Fiferator" Aerobic Stabilization
Reverse Osmosis
Reverse Osmosis
Aerobic Stabilization
Aerobic Stabilization
Aerobic Stabilization
No Process
No Process
Aerobic Stabilization
Aerobic Stabilization
Aerobic Stabilization
Aerobic Stabilization
Hypochlorination
Aeration Stabilization Trickle
Filter
Spiral Bio-Filter
Aerobic Stabilization
Aerobic Stabilization
Aerobic Stabilization
Aerobic Stabilization
Lafayette, Indiana
Of the nineteen manufacturers listed above fourteen made individual home treatment
units or contemplated making them. These fourteen are:
1. Fifer Industries 8. Wilson Water Purification Co.
2. Yeomans (Cavitette) 9. BiO2 Systems
3. Cromaglass Corp.
4. Converto Co.
5. Jet Aeration Corp.
6. Valdespino Labs
7. Hamilton Southern
10. Svenska Interpur Ab
11. Allenaire, Inc.
12. Convert-All, Inc.
13. Microphor, Inc.
14. Sewerless Toilet Co.
*Mention of a commercial product or manufacturer does not imply endorsement by
the Federal Water Pollution Control Administration.
131
-------
Table A-n. Manufacturers Supplying Information On Plumbing Fixtures*
Plumbing Valves & Fittings
Harcraft Brass, Torrance, Cal.
Speakman Company, Wilmington, Del.
Water Saver Faucet, Chicago, fll.
Mueller Brass Company, Port Huron, Mich.
Sloan Valve Company, Chigago, HI.
Milwaukee Faucets, Inc., Milwaukee, Wis.
Beacon Valves, Waltham, Mass.
Plumbing Fixtures and Water Closets
Kohler Company, Kohler, Wis.
Eljer Plumbingware Co., Pittsburg, Pa.
American Standard Controls Div., NYC, N. Y.
Monogram Industries, Inc.
Incinomode toe., Garland, Texas
LaMere Industries, Walworth, Wis.
Major Appliances
Norge
Westinghouse
Whirlpool
General Electric Co., Schenectady, N. Y.
Kelvinator Division
Kitchen Aid Hobart, Troy, Ohio
*Mention of a commercial product or manufacturer does not imply endorsement by the
Federal Water Pollution Control Administration.
132
-------
Table A-HI. Cost Data For Liljendahl* Vacuum Toilet
COST COMPARISON NO. 1
Estimated cost including a comparison of conventional versus vacuum closets in a
single home:
1. Home with conventional closets:
A. 3" plastic pipe and vents for closets, lavatories,
baths and sink $280. 00
B. 2-conventional closets @ $25, 00 each $50.00
C. Labor (Installation) $165.00
Total $495.00
2. Home with vacuum closets:
A. 2" plastic pipe and vents for lavatories,
baths and sink $175.00
B. 1-1/2" plastic pipe for closets $ 60. 00
C. 2-vacuum closets @ $57.00 each $114.00
D. Labor (Installation) $175.00
Total $524.00
3. Cost of vacuum collection system for single
home installation, including vacuum pumps,
tank, miscellaneous piping, gages, electrical
equipment and sludge transport unit. $1300.00
4. Cost of vacuum collection system for 100 homes,
including vacuum pumps, tanks, miscellaneous
piping, gages, electrical equipment, sludge pump
and shelter $7500.00
*Mention of a commercial product or manufacturer does not imply endorsement by
the Federal Water Pollution Control Administration.
133
-------
Table A-m. (Cont'd)
COST COMPARISON NO. 2
The cost of water used by the conventional closet versus the vacuum closet was
evaluated based on the following information received from private industry,
government, state and local authorities:
1. People per home - 4.5
2. Total gallons per day per person - 75
3. Water rates (national average)
4. Gallons per day per person used by conventional closet - 30
5. Gallons per day per person used by vacuum closet - 2-1/4
(based on present design)
A. Cost of water used in home per month with $6.29
conventional closet
B. Cost of water used in home per month with $3.71
vacuum closet
Savings per month $2.58
COST COMPARISON NO. 3
The additional cost of electricity to operate the vacuum pump was estimated based
on $. 015 per K. W. H.:
1. Additional cost for single home vacuum collec- $ . 837
tion system with 1/4 HP pump per month
2. Additional cost per home in allotment of 100 $ .183
homes with vacuum collection system with 5 HP
pump per month
134
-------
Table A-IV. Preliminary Cost Comparisons (Annual Cost in Dollars per Person)
co
en
System
1. Conventional Systems
(a) Sewers (average water cost)
(b) Septic tank, good soil
(c) Septic tank, fair soil
(d) Septic tank, poor soil
(e) Sewers (low water cost)
(f) Sewers (high water cost)
2. Flow Control Showers
3. Flow Control Faucet
(Kitchen or Lavatory)
Annual Waste Total
Equipment and Water Disposal Annual
Operating Cost Cost Cost Cost
Annual Savings;
( - ) Indicates
Increased Costs
jost) q>J.u. uu
(avg. water cost) 10.00
(avg. water cost) 10. 00
(avg. water cost) 10.00
4.80
) "° "
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
(f)
$0.50
0.50
0.50
0.50
0.50
0.50
0.80
0.80
0.80
0.80
0.80
0.80
9.10
9.10
9.10
9.10
4.30
26.00
9.70
9.70
9.70
9.70
4.60
27.70
$J.U. OU
11.20
16.10
33.70
10.50
1 f\ C A
1U, OU
9.50
10.20
14.70
30.80
9.50
9.50
10.10
10.80
15.60
32.70
10.10
10.10
$ŁU. OU
26.10
43.70
15.30
19.10
19.80
24.30
40.40
14.30
36.00
20.60
21.30
26.10
43.20
15.50
38.60
$1.40
1.40
1.80
3.30
1.00
3.10
-0.10
-0.10
0.00
0.50
-0.20
0.50
-------
Table A-IV. (Cont'd)
System
4. Faucet Aerators
5.
CO
05
Automatic Flush
Valve Toilets
6.
Automatic Flush
Toilets (2 Cycles)
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
-------
Table A-IV. (Cont'd)
System
7. Shallow Trap Toilets
CO
8.
English Style
Toilets
9.
English Style
(Dual Flush)
(a)
(b)
(c)
(d)
(e)
CO
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
-------
Table A-IV. (Cont'd)
Siystem
10. Vacuum Flush Toilet
Single Home
11. Recycle Toilets
co
00
12. Incinerator Toilets
Annual
Equipment and Water
Operating Cost Cost
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(d)
(e)
(f)
$ 40.00
40.00
40.00
40.00
40.00
40.00
26.30
26.30
26.30
26.30
26.30
26.30
24.00
24.00
24.00
24.00
24.00
24.00
$ 6.40
6.40
6.40
6.40
3.00
18.30
6.00
6.00
6.00
6.00
2.90
17.10
5.70
5.70
5.70
5.70
2.70
16.30
Waste
Disposal
Cost
$ 6.70
7.50
10.90
22.70
6.70
6.70
6.30
7.20
10.40
21.60
6.30
6.30
6,00
6.80
9.90
20.60
6.00
6.00
Total
Annual
Cost
$ 53.10
53.90
57.30
69.10
49.70
65.00
38.60
39.50
42,70
53.00
35.50
49.70
35.70
36.50
39.60
50.30
32,70
46.30
Annual Savings;
( - ) Indicates
Increased Costs
$ -32.60
-32.70
-31.20
-25.40
-34.40
-25.90
-18.10
-18.30
-16.60
-10.20
-20.20
-10.60
-15.20
-15.30
-13.50
- 6.60
-17.40
- 7.20
-------
Table A-IV. (Cont'd)
CO
CO
System
13. Reuse of Wash Water
for Toilet Flushing
14. Multifiltration
(All Non-Sanitary
Wastes)
15. Reverse Osmosis
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
(f)
Annual
Equipment and
Operating Cost
$ 9.10
9.10
9.10
9.10
9.10
9.10
34.00
34.00
34.00
34.00
34.00
34.00
118.00
118.00
118.00
118.00
118.00
118.00
Water
Cost
$ 5.90
5.90
5.90
5.90
2.80
16.80
4.10
4.10
4.10
4.10
2.00
11.70
4.10
4.10
4.10
4.10
2.00
11.70
Waste
Disposal
Cost
$ 6.70
7.50
10.60
21.30
6.70
6.70
4.30
5.30
7.60
15.90
4.30
4.30
4.30
5.30
7.60
15.90
4.30
4.30
Total
Annual
Cost
$ 21.70
22.50
25. 60
36.30
18.60
32.60
42.40
43.40
44.70
54.00
40.30
50.00
126.40
127.40
129.70
138.00
124.30
134.00
Annual Savings;
( - ) Indicates
Increased Costs
$ -1.20
-1.30
.50
7.40
-3.30
6.50
-21.90
-22.20
-18.60
-10.30
-25. 00
-10.90
-105.90
-106.20
-103.60
- 94.30
-109.00
- 94.90
-------
Table A-IV. (Cont'd)
16.
System
Distillation (All
Non-Sanitary Wastes)
17.
Distillation (All
Wastes - Reuse
Except Drinking)
18. Aerobic Treatment
Annual
Equipment and Water
Operating Cost Cost
(a)
(b)
(c)
(d)
(e)
(a)
(b)
(c)
(d)
(e)
(0
(a)
(b)
(c)
(e)
-------
Table A-IV. (Cont'd)
19.
20.
21.
System
Electrolytic Treat-
ment (In Place of
Septic Tank)
Biological Treat-
ment (Reuse Except
for Drinking)
Coagulation Sedi-
mentation and
Filtration (All
Wastes ,Reuse for
Toilet Flush)
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
(f)
Annual
Equipment and
Operating Cost
$ 53.00
53.00
53.00
53.00
53.00
53.00
57.00
57.00
57.00
57.00
57.00
57.00
35.00
35.00
35.00
35.00
35.00
35.00
Water
Cost
$ 10.00
10.00
10.00
10.00
4.80
28.60
1.50
1.50
1.50
1.50
0.70
4.30
5.70
5.70
5.70
5.70
2.70
16.30
Waste
Disposal
Cost
$ 2.60
2.80
4.00
8.40
2.60
2.60
1.60
2.70
3.90
8.00
1.60
1.60
6.00
6.80
9.90
20.60
6.00
6.00
Total
Annual
Cost
$ 65.60
65.80
67.00
71.40
60.40
84.20
60.10
61.20
62.40
66.50
59.30
62.90
46.70
47.50
50.60
61.30
43.70
57.30
Annual Savings;
( - ) Indicates
Increased Costs
$ -45.10
-44. 60
-40.90
-27.70
-45.10
-45.10
-39.60
-40. 00
-36.30
-23.20
-44. 00
-23.80
-26.20
-26.30
-24.50
-18.40
-28.40
-18.20
-------
Table A-IV. (Cont'd)
to
System
22. Coagulation Sedimen-
tation, Filtration
Adsorption (Reuse
Except for Drinking)
23. Carbon Filtration
and Adsorption of
Non-Sanitary Wastes
(Reuse Except for
Drinking)
(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(c)
(d)
(e)
(f)
Annual
Equipment and
Operating Cost
$ 80.00
80.00
80.00
80.00
80.00
80.00
30.00
30.00
30.00
30.00
30.00
30.00
Water
Cost
$ 1.50
1.50
1.50
1.50
0.70
4.30
4.10
4.10
4.10
4.10
2.00
11.70
Waste
Disposal
Cost
$ 1.60
2.70
3.90
8.00
1.60
1.60
4.30
5.30
7.60
15.90
4.30
4.30
Total
Annual
Cost
$ 83.10
84.20
85.40
89.50
82.30
85.90
38.40
39.40
41.70
50.00
36.30
46.00
Annual Savings;
( - ) Indicates
Increased Costs
$ -62.60
-63.00
-59.30
-45.80
-67.00
-46.80
-17.90
-18.20
-15. 60
- 6.30
-21.00
- 6.90
-------
Table A-V. Questionnaire Distribution
Localities in which questionnaires have been distributed:
1. San Diego, California
2. Rochester, New York
3. Avenel, New Jersey
Newark, New Jersey
New York, New York
4. Tulsa, Oklahoma
Dallas, Texas
Oklahoma City, Oklahoma
Ft. Worth, Texas
5. Chicago, Illinois
6. Ft. Walton Beach, Florida
Cocoa Beach, Florida
7. District of Columbia
8. New London, Connecticut
9. Pomona, California
Approximate number of questionnaires distributed in each locality:
Home Owner Questionnaires 55
Plumbing Contractor Questionnaires 25
Architect-Engineer Questionnaires 15
Sixteen (16) questionnaires were sent to a representative group of plumbing equip-
ment manufacturers throughout the country.
143
-------
Table A-VI. Results of the Survey of Homeowners
No. of
Response
(387) 1. Approximately what is the market value of your home ?
24_less than $15, 000 241J$15, 000 to $30, 000 122 over $30, OOP
(387) 2. How many people live in your home? adults children under 21 (no correlation)
(include non-family members of household).
(387) 3. Where do you get the water for your home? (check one)
285 city water system 66 private well 38 community well
(387) 4. Do you have city sewer service? 247 yes 140 no
If your answer is yes, go to question 15. If your answer is no, complete
entire questionnaire.
(149) 5. How do you dispose of bathroom and kitchen waste waters?
a. septic tank, soil absorption 134
b. cesspool 15
c. other, please specify
(167) 6. What maintenance do you give your sewage disposal system? (please check)
a. Pump out septic tank when plumbing is sluggish 47
b. Add chemicals to septic tank when plumbing is sluggish 26
c. Pump out septic tank every three years j4
d. Check tank every year and pump out when needed 32
e. Other, please describe 38
(139) ' How do you dispose of laundry waste water ?
a. With bathroom and kitchen waste waters 94
b. In a separate system 45 what type ? Soil Absorption (90%)
8. Has your waste disposal system needed service or repair in the past
three years ?
53 yes 33 minor (less than $50) 80 no
20 major (over $50)
(133) 9. How many years has the system been in operation? average 10.9 yr.
(141) 10- Do you think that you need a more effective system ? 57 yes 84 no
(133) 11. Would you be willing to pay more for a trouble-free system? 66 yes 67 no
144
-------
Table A-VI. (Cont'd)
(136) 12. Would you prefer an individual household treatment system or a community
treatment system?
55 individual household system 81 community system
(134) 13. Septic tank systems cost between $500 and $2000 to install. Would you
consider the same price range to be a reasonable cost for obtaining a
system that would provide service comparable to that provided by city
sewers ? 110 yes 24 no
(127) 14. The city sewer service charge (often included in property taxes or collected
with water charges) varies from about $25 to more than $200 per year.
Would you be willing to pay a comparable price for similar service for
your home? 77 yes 50 no
15. Would the reuse of treated waste water from bathing or laundering be
acceptable to you for:
(374) a. Toilet flushing 306 yes 68 no
(371) b. Lawn or garden watering 303 yes 68 no
16. Would you object to using any of the following water saving devices in
your home ? (Please check one column for each device)
Would Would Not
Object Object
/376) a. Water saving faucets and shower heads
that deliver adequate, but not excessive
water. 51 325
(378) b. Direct flush toilets such as are found
in most public restrooms and which use
only about 1/2 the water of the common
tank type toilet. 32 346
(365) c. Toilets with separate flush cycles for
liquid and solid sanitary wastes. 78 287
(366) d- Home urinals. 231 135
e. Toilets that disinfect and reuse flush
water many times, such as those
found on the planes of major airlines. 197 169
(370) 17. Do you feel that your water and waste disposal systems prevent your family
from being exposed to disease ? 312 yes 58 no
(387) 18. Do you wish to have a summary of the information obtained from this questionn-
aire sent to you? 196 yes 191 no
If yes, please provide your name and address on the separate sheet of paper
enclosed.
145
-------
Table A-VF Results of The Survey of Plumbing Contractors
No. of
Responses
(38)
(39)
(36)
(39)
(36)
(38)
(42)
(26)
(35)
(24)
each use.
b.
c.
d.
e.
for urine and feces
Urinals
those found on jet aircraft
f. Other, please specify
b.
urine and feces
d. Urinals
on jet aircraft
f. Other, please specify
(Use additional page if necessary)
ly of these
r "no" for
or shower heads.
ir toilets
flush cycles
and reuse
;imes, such as
craft
r
In Private
Homes
Yes No
27 11
18 15
4 31
12 16
1 34
installation difficulties with any of
or shower heads
ir toilets
i flush cycles for
and reuse flushing
uch as those found
r
No Installa-
tion Problem
(check)
37
25
16
30
14
In Commercial
Applications
Yes No
24 13_
35 4
5 31
35 4
2 34
these devices ?
Possible
Installation
Problem
(Please Describe)
1
17
10
5
10
146
-------
Table A-VII (Cont'd)
No. of
Responses
(40)
(38)
(37)
(32)
(34)
(33)
(40)
(42)
(38)
(38)
3. If, in your opinion, the installation of these devices would require increased
costs, do you think homeowners would accept these costs? (Check one column
for each device.)
Increase
No Increase Required
Increase
Required
Increase
Required But Not
And Acceptable Acceptable
(39)
(31)
(34)
(29)
b.
c.
d.
e.
a. Water saving faucets or shower
heads
Direct flush valves for toilets
Toilets with separate flush
cycles for urine and feces
Urinals
Toilets that disinfect and
reuse flushing water many times,
such as those found on jet air-
craft
f. Other, please specify
8
24
8
14
15
24
Would you recommend installation of any of these devices in private homes?
(Please check)
Yes No
a. Water saving faucets or shower heads
b. Direct flush valves for toilets
c. Toilets with separate flush cycles for urine and feces
Urinals
IS-
IS-
d.
e.
Toilets that disinfect and reuse flushing water many times,
such as those found on jet aircraft
26
f. Other, please specify
Without considering cost, how would you rate public acceptance of these devices
in single family homes? (Check one column for each device.)
Favorable Neutral Opposed
a. Water saving faucets or shower heads 27 9 _4 _
b. Direct flush valves for toilets 12 13
c. Toilets with separate flush cycles for
urine and feces 13 Ifi
d. Urinals
21
147
-------
No. of
Responses
(36)
Table A-VH. (Cont'd)
e. Toilets that disinfect and reuse
flushing water many times, such
as those found on jet aircraft
Favorable Neutral Opposed
5 10 21
f. Other, please specify
6 Additional comments or suggestions:
148
-------
Table A-VIJI. Results of the Survey of Architects and Engineers
No. of
Responses
(29) 1. Please indicate your major design interest:
housing single family apartments and
11 developments _7 homes 29 commercial buildings
(29) 2. Various devices designed to minimize water consumption and waste water
volume (e. g., water saving faucets and shower heads, direct flush toilet
valves, home urinals) are now commercially available. In your present
designs for private and development housing do you ever specify the use
of such devices ? 9 yes 20 no
If answer is yes, please specify
3. Would you object to specifying any of the following water saving devices:
Would Would Not
Object Object
(29) a. Water saving faucets or shower heads J* 27
(28) b. Direct flush toilet valves _j> _§L_
(29) c. Toilets with separate flush cycles for urine
and feces
6 20
'26) d. Home urinals
(28) e. Toilets that disinfect and reuse flush water
many times such as those found on the planes
of major airlines J JJL_
f. Other, please specify
(2l\ 4. Approximately what cost do you usually figure for waste disposal
(not including internal plumbing) for homes that will not be connected to a
city sewer system? average $1100; Range $500 to 2000.
5 What cost do you usually figure for connecting to the municipal sewer system
(not including internal plumbing) ? average $325: Range $25 to 900.
149
-------
Table A-VET. (Cont'd)
No. of
Responses
6. What maximum cost for either a private or community waste disposal system
do you think would be acceptable to a home buyer?
Annual
Initial Operating
Cost Cost
(14) In homes valued at less than $15,000 $410 $45
(14) to homes valued at $15,000 to $29,999 fid*. 35
(13) in homes valued at $30,000 and up 900 75
(28) 7. to your designs would you find acceptable the reuse of treated waste water
from, bathing and laundering for toilet flushing or for lawn and garden
irrigation? 24 yes 4 no
Please comment.
(25) g. to your designs have you considered replacing septic tanks with individual
household aerated treatment units? 5 yes 25 no
Please comment.
(16) 9. to housing developments of more than twenty-five homes do you usually
specify community sewers and sewage treatment? 9 yes _7 no
Please comment.
150
-------
Table A-Vm. (Cont'd)
No. of
Responses
(28)
(23)
(25)
10. Do you think that others in your profession would object to the following
proposals ?
Specification of water saving plumbing devices
Specification of aerobic treatment systems
Specification of water reuse systems
11. What leeway does the plumbing contractor have in selecting substitutes for
the systems specified in the contract?
Most
Others
Would
Object
_0
1
J
Most
Others
Would Not
Object
28
22
_23_
12. Additional comments or suggestions:
151
-------
Table A-IX. Results of the Survey of Plumbing Equipment Manufacturers
No. of
Responses
1. Does your company manufacture any of the following
water saving devices at the present time ? (please check)
(8) a. Water saving faucets or shower heads _JL -JL
(6) b. Direct flush toilet valves _2_ _4-
(6) c. Toilets with separate flush cycles for urine and feces _Q_ _Ł_
(7) d. Home urinals _l_ -fi_
e. Other, please specify m
2. Do you anticipate an increased demand from homeowners
and contractors for any of these devices in the near future ?
(please check)
(8) a. Water saving faucets or shower heads .3 _5_
(6) b. Direct flush toilet valves _!_ _Si_
(7) c. Toilets with separate flush cycles for urine and feces J_ _6_
(7) d. Home urinals JL JL
e. Other, please specify
Comments:
3. If you are not now manufacturing any of these devices, do you
have plans to manufacture any of them in the near future ?
(please check)
(6) a. Water saving faucets or shower heads 1 JL_
(5) b. Direct flush toilet valves _!_ _!_
(6) c. Toilets with separate flush cycles for urine and feces 1 _5__
(6) d. Home urinals JL. JL.
e. Other, please specify
152
-------
Table A-IX. (Cont'd)
No. of
Responses Yes No
4. Would you begin manufacturing any of these devices if
increased water rates, sewage rates, or fuel rates for
water heating made water conservation more attractive ?
(please check)
(5) a. Water saving faucets or shower heads __ *
(5) b. Direct flush toilet valves Ł 5
(7) c. Toilets with separate flush cycles for urine and feces 1 __
(7) d. Home urinals __ 6
e. Other, please specify
5. Please estimate selling cost of these devices if manufactured
on a mass production basis. Again, it is stressed that only
estimates are asked for and that these figures will be used
only to approximate a total for system cost.
(5)
(3)
(3)
(3)
a.
b.
c.
d.
e.
Water saving faucets or shower heads $10-20; $18; 50-8'
Direct flush toilet valves $8; $25
Toilets with separate flush cycles
feces $88, $60, 50% more
Home urinals $40, $40, 10% less
Other, please specify
; 20% more
for urine and
6. How would these costs compare with the present retail cost of
the systems now used?
Less More
Expensive Expensive
(6)
(5)
(5)
(5)
a. Water saving faucets or shower
heads
b.
c.
d.
e.
Direct flush toilet valves
Toilets with separate flush
cycles for urine and feces
Home urinals
Other, please specify
0 3
0 4
0 5
2 0
D7o more; *uy0
30% more
No Significant
Change
3
1
0
3
153
-------
Table A-IX. (Cont'd)
No. of Yes No
Responses
7. Do you think these devices would be more difficult for
plumbers to install than conventional hardware ?
(8) a. Water saving faucets or shower heads ^ J
(6) b. Direct flush toilet valves 0 6
(6) c. Toilets with separate flush cycles for urine and feces 2 4
(6) d. Home urinals 0 6
e. Other, please specify
Comments:
8. How would you rate public acceptance of these devices in private homes.
Favorable Neutral Opposed
(8) a. Water saving faucets or shower heads 4 2 2
(7) b. Direct flush toilet valves 3 2 2
(7) c. Toilets with separate flush cycles
for urine and feces 2 1 4
(7) d. Home urinals 3 0 _4
e. Other, please specify
9. Additional comments or suggestions:
154
* U. S. GOVERNMENT PRINTING OFFICE : 1970 O - 405-432
------- |