EPA-600/2-76-289
December 1976
Environmental Protection Technology Series
DEVELOPMENT AND TESTING OF A
WASTEWATER RECYCLER AND HEATER
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed to develop and
demonstrate instrumentation, equipment, and methodology to repair or prevent
environmental degradation from point and non-point sources of pollution. This
work provides the new or improved technology required for the control and
treatment of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
-------
EPA-600/2-76-289
December 1976
DEVELOPMENT AND TESTING OF A WASTEWATER
RECYCLER AND HEATER
by
Victor J. Guarino
Robert A. Bambenek
CHEMTRIC Incorporated
Rosemont, Illinois 60018
EPA Contract No. 68-03-0436
Project Officer
Harry E. Bostian
Wastewater Research Division
Municipal Environmental Research Laboratory
Cincinnati, Ohio 45268
This study was conducted
in cooperation with
National Aeronautics and Space Administration
Department of Housing and Urban Development
U.S. Army Medical R § D Command
U.S. Coast Guard
MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
-------
DISCLAIMER
This report has been reviewed by the Municipal Environmental
Research Laboratory, U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the
contents necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade names
or commercial products constitute endorsement or recommendation
for use.
11
-------
FOREWORD
The Environmental Protection Agency was created because of
increasing public and government concern about the dangers of
pollution to the health and welfare of the American people.
Noxious air, foul water, and spoiled land are tragic testimony
to the deterioration of our natural environment. The complexity
of that environment and the interplay between its components
require a concentrated and integrated attack on the problem.
Research and development is that necessary first step in
problem solution and it involves defining the problem, measuring
its impact, and searching for solutions. The Municipal Environ-
mental Research Laboratory develops new and improved technology
and systems for the prevention, treatment, and management of
wastewater and solid and hazardous waste pollutant discharges
from municipal and community sources, for the preservation and
treatment of public drinking water supplies, and to minimize the
adverse economic, social, health, and aesthetic effects of pollu-
tion. This publication is one of the products of that research;
a most vital communications link between the researcher and the
user community.
The work described here presents the design and evaluation
of an appliance intended for use in applications where it is
economical to recover usable hot water from wastewater without
the expenditure of additional energy.
Francis T. Mayo, Director
Municipal Environmental Research
Laboratory
111
-------
ABSTRACT
This report describes the design, fabrication and testing
of a distillation unit that utilizes the flash evaporation and
vapor compression processes to recover usable hot water from
contaminated wastewater. This unit does not require the use
of any expendable materials, and it is capable of recoverying
more than 96% of the available wastewater while using less than
80 watt-hours of energy per liter of recovered water.
Two units were fabricated—one for the U.S. Army Medical
R § D Command, and one for the National Aeronautics and Space
Administration. The Army unit was tested for 38 days with real
laundry water, and 21 days with a synthetic brine water that
simulates concentrated wastewater from a hospital. The results
achieved with the real laundry water were as expected-- that
is, neutral water with very low solids and low turbidity; how-
ever, the presence of organic volatiles and ammonia in the syn-
thetic brine water caused the water recovered during the second
test to be unacceptable--thus indicating that pretreatment
and/or additional processing is necessary when these contami-
nants are present.
This report also includes an economic assessment that
concludes that this type of unit is advantageous for use in
areas where fresh water must be transported by vehicles. To
justify the use of this appliance in metropolitan areas, how-
ever, a lower cost design and mass production techniques are
required.
IV
-------
Pa
CONTENTS
Foreword [[[
Abstract ........................................ ........... iv
List of Figures ............................................ vii
List of Tables ............................................. viii
Abbreviations and Symbols .................................. ix
Acknowledgments ............................................ xi
Section I Introduction .................................. 1
Background ................................. 1
Scope of Work .............................. 4
Section II Conclusions ................................... 6
Section III Recommendations ............................... 7
Section IV Design Analysis ............................... 9
Conceptual Arrangement ..................... 9
Design Requirements ........................ 11
Thermodynamic Model ..... ................... 12
Calculations ............................... 15
Section V Prototype Design .............................. 23
Weldment Assembly .......................... 23
Processor Tank Assembly .................... 23
Components and Controls .................... 29
Section VI Evaluation Tests .............................. 34
Real Laundry Water ......................... 3-4
Test Apparatus .......................... 34
Test Procedure .......................... 37
Test Results ............................ 38
Synthetic MUST Brine ....................... 47
Test Description ........................ 53
Test Results ............................ 54
-------
Contents continued.
Section VII Discussion of Results 65
Design 65
Water Quality 66
Section VIII Economic Assessment 68
Total Annual Costs 68
Water and Sewer Costs 70
Potential Demand 72
Section IX Appendices 73
Design Calculations 73
Design Details » 77
Evaporator Tank 77
Condenser Tank 78
Condenser Coil 79
Storage Tank 79
Weldment Assembly 80
Insulation 80
Analytical Methods 80
CHEMTRIC Analyses 80
Subcontracted Analyses 82
Installation, Operation § Maintenance ... 83
Installation 83
Preliminary 83
Filling § Heating 85
Start-Up 87
Operation 87
Maintenance 89
Replacement Parts 90
Compressor Drive Assembly 90
Recycle Pump Assembly 91
Condensate § Purge Pumps 91
Control Components 91
VI
-------
LIST OF FIGURES
Number Page
1 Proposed Water Recycler/Heater 3
2 Conceptual Arrangement of Recycler/Heater 10
3 T-S Diagram for Vapor Compression 13
4 T-S Diagram for Flash Evaporation 13
5 Schematic Arrangement of Processor 14
6 Results of Design Calculations 16
7 Heat Transfer Model of Condenser Coil 19
8 Model of Insulation Heat Loss 21
9 Effect of Boiling Point Elevation 22
10 Recycler/Heater With Door Removed. 24
11 Recycler/Heater With Test Equipment * 25
12 Recycler/Heater Without Insulation ... 26
13 Recycler/Heater Physical Dimensions 27
14 Process Tank With Head Removed 28
15 Sketch Showing Demister Location 30
16 Arrangement of Components and Controls 31
17 Recycler/Heater Electrical Schematic 33
18 Real Laundry Water Test Arrangement 35
19 Jet-Pump Purging Arrangement 48
20 Daily Synthetic Brine Ingredients 52
21 Synthetic Brine Test Initial Arrangement 56
22 Synthetic Brine Test Final Arrangement 57
A-l Installation Schematic 84
A-2 Control Schematic 86
VII
-------
LIST OF TABLES
Number Page
x
1 Component Identification 32
2 Laundry Tests Daily Analyses 39
3 Laundry Test No. 32 Detailed Analyses 41
4 Laundry Test Feed and Concentrate 43
5 Performance During Laundry Test No. 2 44
6 Performance During Laundry Test No. 20 45
7 ., Performance During Laundry Test No. 38 46
8 Synthetic Brine Formula 50
9 Synthetic Brine Test Modes 55
10 Synthetic Brine Test Daily Analyses 58
11 Synthetic Brine Test Detailed Analyses 59
12 Comparison of Organics Determinations 61
13 Purge Gas Analyses 62
14 Performance During Brine Test No. 1 63
15 Performance During Brine Test No. 21 64
16 Projected Cost of Recycler/Heater 69
17 Typical Water and Sewer Costs 71
A-l Recycle Flow Requirements 74
A-2 Compressor Power Requirements 75
A-3 Pump Power Requirements 76
Vlll
-------
LIST OF ABBREVIATIONS AND SYMBOLS
AQ Outside area of insulation jacket.
AI Outside area of processor tank.
Cp Isobaric heat capacity.
D Compressor displacement.
DQ Outside diameter of condenser coil.
D^ Inside diameter of condenser coil.
h-L Enthalpy of saturated vapor at temperature T]_.
Ji2 Enthalpy of saturated vapor at temperature T£.
1*3 Enthalpy of saturated vapor at temperature T3.
hf Enthalpy of saturated liquid at temperature T-^.
hf Enthalpy of saturated liquid at temperature Te.
h0 Enthalpy of influent.
H Heat transfer coefficient due to convection.
Hr Heat transfer coefficient due to radiation.
K Compressor slip coefficient.
k Thermal conductivity of condenser coil material.
k' Thermal conductivity of insulation material.
L Length of condenser coil.
M Compressor productive speed.
N Compressor shaft speed.
n Number of coils in condenser.
n' Number of spirals in each condenser coil.
P-j_ Evaporator saturation pressure.
Po Condenser saturation pressure.
Pe Liquor pressure at exit of condenser coil.
q^ Heat loss from processor.
RL Condenser coil heat transfer resistance.
Ry Condenser coil vapor side heat transfer resistance,
IX
-------
Abbreviations and Symbols Continued.
RW Condenser coil wall heat transfer resistance.
rQ Minimum spiral radius of condenser coil.
S Compressor slippage rpm.
Ta Ambient temperature.
Tj^ Vapor temperature in evaporator.
T2 Vapor temperature at compressor discharge.
Tj Vapor temperature in condenser.
Te Liquor temperature at exit of condenser coil.
Tm Mean temperature (Te+T1)/2.
T Surface temperature of insulation jacket.
t Condenser coil wall thickness.
U Condenser coil overall heat transfer coefficient,
V Liquor velocity in condenser coil.
Ws Compressor motor shaft power.
W' Recycle pump motor shaft power.
x Fraction vapor content in recycle liquor.
y Thickness of insulation jacket.
AP Vapor pressure rise across compressor.
AP1 Liquor pressure drop across condenser coil.
ATm Mean temperature difference (T3-Tm) .
Ar Condenser coil spiral spacing.
v Vapor specific volume.
v' Liquor specific volume.
U> Recovery rate.
ci) Recycle liquor flow rate.
Log mean temperature difference.
Ratio of specific heats.
Compressor polytropic efficiency.
Compressor volumetric efficiency.
Compressor motor efficiency.
Recycle pump hydraulic efficiency.
-------
ACKNOWLEDGMENTS
This project was carried out by Victor Guarino (Project
Engineer) under the direction of Robert Bambenek (President of
CHEMTRIC, Inc.). Walter Jasionowski served as chemical engi-
neering consultant throughout the program and provided valuable
guidance in setting up the water quality evaluation tests. All
of the day-to-day testing of the equipment and the in-house wa-
ter analyses were conducted by Andrew Murman (Technician) and
Reid Urban (Biochemist); their work is gratefully acknowledged.
The detailed chemical analysis of the product water for trace
metals, ions and organics were carried out by the Nalco Chem-
ical Company, Analytical Services Division.
Five government agencies contributed financially to this
project; sincere appreciation is expressed to these supporters
and the respective project monitors: Dr. Harry E. Bostian,
Environmental Protection Agency; Lt. Col. LeRoy H. Reuter,
U.S. Army Medical R § D Command; Mr. James A. White, U.S.
Coast Guard; Mr. Jeff Hamilton, National Aeronautics and
Space Administration; and Mr. J. H. Rothenberg, Department
of Housing and Urban Development. Special acknowledgment is
due to Dr. Harry E. Bostian for his support as Project Officer,
and to Lt. Col. LeRoy H. Reuter for providing chemical con-
stituents and supporting organic analyses conducted by the
Environmental Chemistry Branch at Fort Detrick.
XI
-------
SECTION I
INTRODUCTION
The National Environmental Research Center (NERC) of the
Environmental Protection Agency (EPA) awarded contract 69-03-0436
to CHEMTRIC Incorporated on 16 April 1974 for the "development
and testing of a wastewater recycler and heater". This report
summarizes the technical work performed under that contract; the
installation, operation and maintenance requirements of the Re-
cycler/Heater are described in the Appendices.
The Recycler/Heater utilizes previously developed space-
craft technology to recover usable hot water from wastewater; it
can be used in domestic, industrial, military and marine applica-
tions. Consequently, EPA contract 68-03-0436 was jointly mon-
itored and funded by five Federal Agencies -- namely, the Envi-
ronmental Protection Agency, the National Aeronautics and Space
Administration, the Department of Housing and Urban Development,
the U.S. Army, and the U.S. Coast Guard.
Background
The continuously increasing use of fresh water from public
water supplies and the attendant increase of wastewater has
created two major problems: conserving our limited fresh water
reserves, and stablizing the burden on our limited capacity water
and wastewater treatment systems. Since domestic water usage
accounts for nearly 50% of the water supplied from public utili-
ties, long term conservation policies should have an important
impact on the stabilization of per capita costs to build and
operate these systems.
Methods of reducing home water consumption have been analyz-
ed. 1»2>3 These studies, sponsored by the Environmental Pro-
1.Bailey, James R.; Benoit, Richard J.; Dobson, John L.; Robb,
James M. and Wallman, Harold, A_Study of Flow Reduction and
Treatment of Waste Water from Households. General Dynamics,
Electric Boat Division, Groton, Conn. ("1969)
Z.Cohen, Sheldon and Wallman, Harold, Demonstration of Waste Flow
Reduction from Households. General Dynamics, Electric Boat
Division, Groton, Conn. (1974)
3.Chan, Michael L., Wastewater Flow Reductions Study, Energy
Resources Co., Inc^Cambridge, Mass.(1975)
-------
tection Agency, focus primarily on the use of water-saving plumb-
ing fixtures, public education, metering and pricing schemes, and
building codes. Cohen and Wallman2 have evaluated a pilot re-
cycle system to reuse bath and laundry water for toilet flushing
and lawn watering. This system used filtration and chemical dis-
infection and did not recover hot water.
Water recycling has been used for many years in industrial
plants to reduce pretreatment costs and/or concentrate wastewater
for disposal or mineral recovery. In Windheock, South Africa,
30% of the domestic water supply is recovered from the sewage
treatment plant.4 Thus, large-scale recycling has already been
justified in certain applications and areas. Now the question
is: How and where can water recycling be justified on a house-
hold-size scale?
Since 1958, a relatively large amount of research has been
performed on processes that appear to be suitable for recycling
water onboard manned spacecraft. The most developed system
utilizes reverse osmosis to recover usable water from expended
wash water, and compression distillation followed by adsorption
filtration to recover potable water from pretreated urine,
urinal flush water, humidity condensate, and the reverse osmosis
concentrate.5 The compression distillation unit, which CHEMTRIC
developed under several NASA contracts, was selected because it
requires less energy and less make-up water than the other pro-
cesses considered for spacecraft.
In 1971, using technology acquired under NASA contracts,
CHEMTRIC personnel devised the compression distillation unit
illustrated in Figure 1. The unique feature of this design is
its ability to first use the input energy to distill water from
wastewater, and finally recover most of this energy as sensible
heat in the product water. Thus, the cost to operate this unit
should not be any greater than an equivalent-capacity, electric-
ally operated water heater. Other advantages of this design are:
A. Wastewater is processed at 165°F to assure
the delivery of sterile product water.
B. Flash evaporation, instead of submerged evaporation
surfaces, is used to minimize the effects of dis-
solved solids on distillation rate and thereby re-
covered a high percentage of the available water.
4.Weinstein, Richard, H., Water Recycling for Domestic Use,
Astronautics § Aeronautics, March 1972, 44-51.
S.Ziegler, Leon, Water and Waste Management System Design
for a Space Station Prototype, ASME Publication 72-ENAv-8.
August 1972.
-------
HOT COMDENSk TE
COMPRESSOR
MOTOR
pome
THERMAL
/ISOLATION
HTR.
HOT
WATER
FRESH
WATER
Figure 1.
PROPOSED WATER RECYCLER/HEATER
-------
Subsequent to the conception of the unit in Figure 1,
CHEMTRIC proposed the development of this system to the following
agencies for the reasons stated.
Environmental Protection Agency (EPA)
Recovery of usable hot water from
domestic wastewater.
National Aeronautics § Space Administration (NASA)
Utilization of NASA technology for
domestic applications.
Department of Housing § Urban Development (HUD)
Recovery of usable hot water from
domestic wastewater.
U.S. Army Medical R§D Command (AMRDC)
Recovery of usable hot water from field
hospital wastewater.
U.S. Coast Guard (USCG)
Recovery of shower wastewater for reuse
as laundry water.
Since all of these agencies were found to be interested
in the proposed system, they met with CHEMTRIC personnel at NASA
Headquarters on 17 October 1973. At this meeting it was agreed
that they would jointly fund an EPA contract with CHEMTRIC for
the development of the proposed system. Subsequently, CHEMTRIC
was awarded EPA contract 68-03-0436. '
Scope of Work
The objective of this program was to design, fabricate and
evaluate a prototype unit which is capable of recoverying up to
6 gallons per hour of usable 165°F water from .room-temperature
wastewater, using no more than 1800 watts of electrical power.
This capacity was selected because it (1) corresponds to the
smallest, commercially-available, domestic water heater, and (2)
equals the highest distillation rate attainable at 165°F with
the smallest vapor compressor used by CHEMTRIC for spacecraft
water recovery systems.
Before the detail design drawings were prepared, the basic
design was analyzed mathematically to determine the combination
of independent parameters which would yield a design requiring
no more than 1800/6, or 300 watt-hours per gallon (79 watt-hours
-------
per liter). When this was determined, the detailed design draw-
ings were prepared.
Two units were fabricated so that the AMRDC and at least
one other agency would each have a unit to evaluate at their
facilities. The second unit was eventually assigned to the NASA
Langley Research Center, but delivered on a loan basis to the
Naval Ships R§D Center at Annapolis for evaluation as a concen-
trator for shipboard wastes.
Evaluation of the device was primarily concerned with a
quanitative analysis of the recovered water and the thermo-
dynamic performance of the system. To this end two wastewater
streams were processed - i.e., real laundry water and a synthe-
tic waste which simulates the brine from the AMRDC Medical Unit,
Self contained, Transportable (MUST) hospital water treatment
system. It was originally proposed that shower water and sink
water would also be processed, but hardware development problems
delayed the testing phase and time did not permit evaluations
with these waste streams. It was recognized, however, that the
simulated brine waste stream was a synthetic composite of con-
centrated laundry, shower, and sink wastes. For all test runs,
system data and water samples for chemical and physical analysis
were collected at regular intervals. All the detailed results
are presented in this report under Section VI. In Sections IV
and V the detailed design analysis and description of the proto-
type design are presented.
-------
SECTION II
CONCLUSIONS
The results of this program have demonstrated the fea-
sibility of an automatic and self-contained appliance that can
recover and store usable hot water from waste laundry water,
using essentially the same amount of energy as an equivalent-
capacity water heater. It has been shown by extended evaluation
tests with a waste stream of real laundry water that this unit
is capable of recovering sterile hot water at a steady state
rate of 22.7 liters/hour (6 gph) with a specific energy draw of
79 watt-hours/liter (299 watt-hours/gal), without the use of any
expendable chemicals. It has also been shown by extended
evaluation tests with a feed that simulates hospital wastewater
preconcentrated by ultrafiltration and reverse osmosis that this
unit can increase the solids concentration of a waste water from
less than 2% to at least 29.31.
When real laundry water is processed, the product water is
typically neutral with a turbidity below 10 Jtu and has COD and
total dissolved solids levels below 75 mg/1. When the feed stock
contains a large quantity of volatile liquids, which the hospital
waste simulant contained, low boiling point volatiles such as
ammonia and the alcohols will carry over and dissolve in the pro-
duct water. In this case, therefore, pretreatment and/or post-
treatment is required to obtain usable hot water.
The results of a manufacturing cost analysis have shown
that a conservative annual cost (that is, a maximum annual
cost) of this appliance is $717 per year. This is based on a
production quantity of 10,000 units per year, a 20-year opera-
tional life, and an interest rate of 81. Since this appliance
could typically conserve 166,000 liters (44,000 gallons) per
year of potable water per household, economic feasibility is
based on comparison of unit cost per year to savings in water
and sewer costs. It has shown that at the present time (1974
data), these savings are typically under 200 dollars in metro-
politan areas across the United States (except in isolated cases
such as the outskirts of Fairbanks and Anchorage where the sav-
ings could be as high as $2,100 per Year). Economic feasibility
therefore is not demonstrable at present on a large scale. How-
ever this analysis does point out that should water cost increase
in the future by a factor of 4 or more, or if the cost of the
appliance is reduced by a factor of 4 or more to yield a "break-
even" situation, a viable demand for household water recovery
with the appliance would be possible.
6
-------
SECTION III
RECOMMENDATIONS
Upon completion of the development tests, the two pro-
totype units constructed as part of this development program
were shipped to the following locations for further evaluation
of their performance when processing various wastewaters.
Unit #1:
U.S. Army Medical Bioengineering Laboratory
Fort Detrick, Frederick, Maryland
Unit #2:
Naval Ships R§D Center
Annapolis, Maryland
The tests planned at Annapolis, with preconcentrated real
laundry water, should be continued until the solids concentra-
tion causes the recovery rate and/or the water quality to fall
below the Navy's acceptable level for shipboard use.. With these
data it will be possible to design a shipboard unit that has the
required overall performance.
The tests planned at Fort Detrick with simulated hospital
wastewater should be performed to determine whether processing
real brine yields ammonia and organic volatiles, and if it does,
whether acidifying and degassing reduce the quantity of these
contaminants to an acceptable level.
A cost reduction study is recommended to determine the
design that yields the lowest "installed cost". For example,
the prototype assemblies contain an integrated weldment assembly
of the processor tank, sump tank and hot water storage tank;
separation of these tanks would facilitate transportation and
allow the use of a standard storage tank. The tanks could be
fastened together after installation to maintain the advantage of
conduction between the two tanks (i.e., only one heating element
required). A value engineering study would reveal how each item
should incorporate only those functions and materials necessary
and how these might be arranged differently to effect cost re-
ductions in the overall appliance design.
In addition to a cost reduction study, it is necessary to
set up the hot water recovery appliance in a real household
-------
situation so that user reactions can be fully integrated into
the design, and water balances and cycle times can be monitored.
In this situation, sink water and/or shower water could also be
processed to provide the make-up wash water.
Finally, the Recycler/Heater should be considered for
applications where its ability to concentrate solutions to more
than 30% solids yields additional cost savings. Examples of
this are applications where the concentrate must be stored and
transported to a storage facility or disposed by means of in-
cineration and/or pyrolysis.
-------
SECTION IV
DESIGN ANALYSIS
This section presents the thermodynamic, fluid mechanical,
and heat transfer analysis which preceded the hardware design.
Conceptual Arrangement
Figure 2 shows a sketch of the system concept. The system
is comprised of three basic elements--a processor tank, a sump
or wastewater holding tank, and a hot water storage tank. The
processor tank, which is the primary element and the subject of
this analysis, incorporates the processes of flash evaporation
and compression distillation. The sump tank is used to control
the feed of waste water into the processor and also serves as a
phase separator, as described in Section V. The storage tank
is used to hold the hot product water from the processor and to
maintain the product water temperature when the processor is
shut down.
Referring to Figure 2, the system operates as follows.
Wastewater enters the sump which contains a float control to
automatically start the processor when the sump is filled (and
automatically turn the processor off when empty). From the sump
it enters the evaporator section of the processor tank on demand
via a liquid level control of the feed valve. The fresh feed is
mixed with previously concentrated liquor, and the solution is
continuously circulated in the recycle loop via a centrifugal
pump (recycle pump). It is seen that the recycle pump takes the
liquor from the evaporator shell and passes it through a heat
exchanger coil located within the condenser shell. The heated
liquor is then returned to the evaporator through a manifold of
spray nozzles where a small portion is flashed into water vapor
and the remainder returned to the recycle loop to become more
concentrated. The vapor is simultaneously drawn into the conden-
ser shell via a small positive displacement compressor which
raises its pressure and temperature. Within the condenser shell
the vapor is directed over the heat exchanger coil containing the
recycle liquor at a lower temperature. The vapor condenses on the
coil and the latent heat is transferred back to the evaporator to
continue the evaporation process. The hot condensate is removed
from the condenser shell and transferred to the storage tank via
a small positive displacement pump (condensate or product water
pump). When the pressure in the storage tank reaches a maximum
the processor is automatically shut down. A thermostatically-
controlled heater then maintains the temperature of the stored
-------
WASTE WATER
FLOAT SWITCH
HEATER/THERMOSTAT
CONDENSATE(Product Water)PUMP
Figure 2 CONCEPTUAL ARRANGEMENT OF RECYCLER/HEATER
-------
water at the pasteruization temperature, which is also the sat-
uration temperature of the condensate in the processor.
The unique feature of the processor is its ability to re-
cycle the latent heat of condensation, and at the same time con-
centrate the waste stream.
Design Requirements
The fundamental design philosophy was to incorporate the
system concept presented in Figure 2 into a practical design for
home use. To this end the following requirements were stipulated.
1. The processing rate should be 6 gph, comparable to
a domestic hot water heater.
2. The condenser temperature should be at the pasteur-
ization temperature, 165°F, to avoid biological con-
tamination.
3. The power required to operate the processor should
be essentially the same as the power to run an
electric water heater of the same recovery rate, which
for a 100°F temperature rise is approximately 1600 to
1800 watts.
4. The physical dimensions of the processor should be such
that the overall width is smaller than a standard re-
sidential door opening, 71 cm (28 in), and the overall
height, including head space for maintenance is smaller
than a standard residential basement ceiling height,
213 cm (84 in).
5. The heat exchanger should be a compact design consist-
ing of two horizontal spirals of copper tubing which
are series wound. The outside diameter of the spirals
should not exceed 48 cm (19 in).
6. The exit temperature of the recycle liquor passing
through the heat exchanger should be 164°F - that is,
one degree less than the condenser temperature.
7. The vapor compressor should be a Gardner-Denver Model
2PDR4, or a Sutorbilt Model 2LB. These compressors
have the respective displacements of 0.033 and 0.035
cubic feet per revolution, and both have a volumetric
efficiency near 90% with air at standard conditions.
8. The recycle pump should be a centrifugal pump with an
efficiency near 501 and a net positive suction head re-
quirement (NPSH) not more than two feet.
These design requirements together with a thermodynamic
11
-------
model of the vapor compression and flash evaporation processes
allowed a complete set of calculations to be performed. The
results of these calculations were used to complete the detailed
mechanical design of the processor.
Thermodynamic Model
For the purpose of performing the numerical calculations
necessary in the mechanical, design of the processor a thermo-
dynamic model was described by using the temperature - entropy
(T-S) diagrams shown in Figures 3 and 4. In Figure 5,a sche-
matic of the processor shows where, within the mechanical sys-
tem, the thermodynamic variables in the T-S diagrams occur.
Following the T-S diagram in Figure 3, vapor in the evaporator
at the saturation temperature TJL and pressure P-j_ is drawn into
the compressor at a recovery rate & , where its temperature and
pressure are raised via an isentropic compression to the super-
heat temperature 1^ at condenser pressure ?2. The compressor
discharges the vapor at temperature T^ directly into a transfer
pipe where it passes to the bottom of the condenser shell and
then upward past the heat exchanger coils. Counter-flowing water
droplets dripping off the cooling coils dissipate the superheat
(h2 - hj) so that the vapor temperature is reduced to the sat-
uration temperature T3 at condenser pressure P'2- The amount of
re-vaporization that occurs is balanced by the amount of conden-
sation that occurs on the walls of the condenser shell. The log-
mean temperature differential €>£„, necessary^ to transfer the latent
heat of condensation (113 - 114) is generated by the liquor flow
' in the condenser coil. The liquor enters the coil at tem-
perature T]_, and exists the coil at temperature T~, which is one
degree less than Tj. The log-mean temperature difference, then,
is :
Following the T-S diagram in Figure 4, the liquor at temperature
1 y undergoes a constant enthalpy expansion (throttling process)
through a manifold of spray nozzles. The expansion occurs be-
tween states Te, Pe and Ti, PI. The nozzles are located within
the evaporator shell in the space above the liquor reservoir to
allow the vapor to separate from the liquid. Energy transferred
(heat) to the liquor, (hft - hf) «0' > just balances the latent
heat of condensation (113 - h^) eC>
In the real system heat losses, hL, occur through the evap-
orator shell to the environment so that the heat rate balance is:
' + ht. (2)
12
-------
Entropy
Figure 3 T-S DIAGRAM FOR VAPOR COMPRESSION
Tl
rt
f-i
V
0)
H
Entropy
Figure 4 T-S DIAGRAM FOR FLASH EVAPORATION
13
-------
CONMNSATE PUMP
Figure 5 SCHEMATIC ARRANGEMENT OF PROCESSOR
14
-------
In order to maintain the rate balance without an external heat
source the processor is insulated so that the following relation-
ship applies.
. ,\* (3)
Rate of Rate of Rate of Rate of Heat Trans-
Heat Loss Superheat Motor Heat fer to Influent
Since the vapor compression ratio is small the superheat
• h-3) is small; also, the feed stock flow x £»' is very
small compared to the recycle flow eO1 . Therefore, in the model
the heat loss is balanced primarily by the motor heat generation.
That is to say, in the thermodynamic model a heat rate balance
occurs such that the rate of heat generated by the motor just
balances the rate of heat loss to the environment. It is this
heat balance that determines the actual steady state operating
temperatures of the processor.
By virtue of the thermodynamic model and design requirements
described above, a detailed quantitative analysis was conducted
in order to arrive at the optimum design point. In the next
Section the optimum design point is shown to be the evaporator
saturation temperature, Tj, at which the power required to ope-
rate the processor is minimal. By proper mechanical design, the
actual steady state operating point can be made to closely coin-
c.ide with the optimum design point.
Calculations
The optimum design point for operation of the processor is
found by computing the vapor compressor and recycle pump power
requirements as a function of evaporator vapor temperature T-^.
Figure 6 presents a graph of the numerical results. It is seen
that for a fixed condenser temperature T3 the compressor shaft
power is inversely related to the evaporator temperature T^ -
but the recycle pump shaft power varies directly with temperature
T-p Therefore, for a given heat exchanger tube diameter there is
a saturation temperature, Tj_, which yields a minimum power re-
quirement. At this point the compressor shaft speed is also spe-
cified. The following steady state equations were used to de-
rive the optimization curve in Figure 6.
The compressor power is related to the evaporation tempera-
ture via the relationship:
% •
(4)
15
-------
1.4
Ws + Ws , TOTAL POWER
OPTIMUM
POINT
N,COMPRESSOR SPEED
Ws, COMPRESSOR POWER
DESIGN REQUIREMENTS:
T3 = 165°F
) = 50.1 Ib/hr (22.7 kg/hr)
Ws'. PUMP POWER
152
154 156 158
TI, EVAPORATOR TEMPERATURE, °F
Figure 6 RESULTS OF DESIGN CALCULATIONS
160
-------
The shaft power, Ws , is dependent on the shaft speed, N, and
again dependent on temperature Tj through the volumetric effi-
ciency
V}
-------
stant enthalpy expansion through the spray nozzles - that is,
(10)
which shows that the fraction x decreases as temperature TI in
creases. Hence the pump capacity requirement, O" > increases,
and, for a fixed heat exchanger size the power requirement in-
creases.
The heat exchanger size requirement is related to the eva
porator temperature, TI, via the heat transfer equation:
I - ( Ha - h*)
u tr D0
It is seen that the length, L, is directly related to evaporator
temperature, TI, through the log-mean temperature diff^rence,€>k,.
Further, the overall heat transfer coefficient, IT , is influ-
enced by the selection of temperature T]_. A model of the heat
transfer in condensation is illustrated in Figure 7. An impor-
tant feature of the heat exchanger design is that the coil oper-
ates at a relatively high Reynolds Number, on the order of 200,
000. This serves two purposes; first, high liquid-side film
coefficients are possible, and second, the probability of fouling
is greatly reduced. The numerical analysis shows that the values
of the liquid side and vapor side film coefficients are of the
same magnitude, on the order of 3000 Btu per hr per square foot
per °F. Another interesting feature is that the liquid side film
coefficient varies inversely with viscosity to the 0.4 power,
which is a relatively weak function. Hence, as the liquor vis-
cosity increases with increase in total solids concentration the
heat transfer is not strongly affected. And since the Reynolds
Number is high (200,000) a threefold increase in viscosity chan-
ges the friction factor by only 181 (Moody Diagram) . This means
that by proper selection of the operating point on the centri-
fugal pump curve, the change in pump flow and power due to a re-
latively large increase in viscosity can be made relatively small.
Viscosity measurements have shown that the viscosity change for
water at 120°F with 30% solids in solution is on the order of 2:1
compared to tap water at room temperature. Since it takes a
viscosity change on the order of 6:1 to noticeably decrease the
head and capacity of a centrifugal pump, the performance of the
recycle loop can be made to be relatively independent of % solute
in the liquor solution.
18
-------
^
(U
^
— I
V
^ "
Figure 7 HEAT TRANSFER MODEL OF CONDENSER COIL (source
for Rv § Ri: McAdams, W. H.,Heat Transmission, 3rd ed.,
McGraw-Hill, New York, 1954.)
19
-------
Results of the numerical analysis shown in Figure 6 were
obtained by evaluating the aforementioned equations at different
values of the evaporator temperature, Tj_, in the temperature range
152°F to 160°F. The minimal power point is shown to occur at an
evaporator temperature of 157°F. At this condition the required
shaft power for the compressor drive and recycle pump are respec-
tively, 0.71 HP and 0.26 HP, and the compressor speed requirement
is 3140 rpm. Therefore, the motor selections for the compressor
drive and recycle pump are respectively, 3/4 HP, and 1/3 HP, and
for a single phase 3450 rpm compressor motor the belt drive ratio
is 1.09. An additional motor is required to transfer the conden-
sate to the hot water storage tank; its power requirement is
small. However, condensate pumps are inefficient - so a 1/8 HP
motor was selected. Hence, the total shaft HP requirement to
operate the processor is, (3/4 + 1/3 + 1/8) HP, or 899 watts.
The total shaft power divided by an average motor efficiency is
the power draw for the processor. For an average efficiency of
50%, the total power draw is 1798 watts - and for a 115 VAC, sin-
gle phase service, the current draw is 15.6 amperes.
Having calculated the power requirements, it remains to
determine the insulation requirement for the processor. From
equation 3 it is seen that the insulation should be sized so that
the heat loss does not exceed the heat generated by the compres-
sor motor. Using a compressor motor e'fficiency of 0.50, the heat
generation is 560 watts. Then the insulation thickness, y, can
be estimated by considering the radial heat transfer across an in-
sulated cylindrical wall. This is illustrated in Figure 8. It
is shown that for the steady state operating condition the insul-
ation thickness need not be greater than 1/4 inch (for an out-
side surface temperature of 120°F). The insulation size, there-
fore, is governed by the stand-by conditions. Thus, a two-inch
thickness was selected for the prototype units in order to mini-
mize the heat loss between runs, and to minimize the start-up
time to reach steady-state operating temperature during a run.
Finally, mention should be made of the operational effect
due to elevation of boiling point by the solute concentration in
the recycle liquor. A rise in boiling point means a reduced
saturation pressure, P^. Therefore, at evaporator temperature,
TI, the vapor is in the superheat region on the T-S diagram of
Figure 3. Then the isentropic compression raises the vapor tem-
perature, T2, to a higher value, T£, which for the same recovery
rate, co , increases the rate of superheat to the value (h^ -
113) ; this is illustrated in Figure 9. The effect of this phen-
omenon was ignored because the unit was to be evaluated using a
variety of wastewaters. On the other hand, it can be accounted
for as CHEMTRIC has done for treated urine and expended photo-
chemicals on other Government contracts.
20
-------
T.
SURFACE,
SURFACE,
INSULATION
EVAPORATOR
SHELL
12" RADIUS
Figure 8 MODEL OF INSULATION HEAT LOSS
Heat loss, hL = Tj-TA
y/k1
AI+AO
(Hc+Hr)A0
where values of (Hc+H-p) are given in
McAdams, W. H., Heat Transmission, 3rd
ed, McGraw-Hill, New York, 1954.
21
-------
Entropy
Figure 9 EFFECT OF BOILING POINT ELEVATION
22
-------
SECTION V
PROTOTYPE DESIGN
Upon completion of the preliminary analysis described in
Section IV, mechanical design of prototype hardware was under-
taken. This section contains a design description of the proto-
type assembly. Two identical units were fabricated, of which one
unit was used for extended evaluation and development tests.
Photographs of the test unit at the test-site in the CHEMTRIC
laboratory are shown in Figures 10 and 11.
Weldment Assembly
The basic elements of the Recycler/Heater system, that is,
the processor tanks, holding tank, and storage tank were incor-
porated into a skeleton weldment assembly as shown in Figure 12.
This was accomplished by seal welding three steel sheet sections
between the process tank and the storage tank, the left and right
tanks respectively in Figure 12. The center section then forms
the holding tank. Material of construction for all three tanks
was low carbon, commercial-grade, 10-gauge steel sheet. Light-
steel channels welded vertically on both sides of the end tanks
form the support legs and frame for securing the insulation
panels. Additional light channels form a rectangular frame at
the bottom to support the recycle and condensate pumps. It is
seen in Figures 10, 11, and 12 that all the external control com-
ponents, wiring and plumbing are accessible when the front insu-
lation panel is removed. In Figure 13, an illustration is given
which shows the pertinent volume, area, and linear dimensions in
the assembly.
Processor Tank Assembly
The processor tank contains the evaporator, condenser and
compressor drive assembly inside a 10-gauge, 24-inch I.D. by 48-
inch long cylindrical shell. The bottom of the shell is closed
by a weld-on, standard-type, 24-inch O.D. head. A ring flange is
closed by a bolt-on standard head containing a matching ring
flange. Removal of the flanged head allows access to the compres'
sor and drive for maintenance. In Figure 14, a top-view photo-
graph reveals the compressor drive assembly, and shows the loca-
tions of the inlet and outlet connections to the heat exchanger,
pipe line to the spray ring, flexible purge gas line, relief
valve, and power connections for the compressor motor. The add-
itional flexible line which runs along the purge gas line was
used for thermocouple wires. A thermocouple was located inside
23
-------
Figure 10 RECYCLER/HEATER WITH DOOR REMOVED
24
-------
Figure 11 RECYCLER/HEATER WITH TEST EQUIPMENT
-------
Figure 12 RECYCLER/HEATER WITHOUT INSULATION
26
-------
(91.4cm)
28 (71.1cm)
(162.6 cm)
Floor space • 1.15m2(12.4ft2)
Envelope = 2.2m3(77.8ft3)
Dry Weight =499 kg(1100 Ib)
4-
OVERFLOW
FEED
__v
8
75 (190.5;cm)
Storage Volume - 100 Gal (379L)
Sump Volume =29 Gal. (110 L)
Recycle Loop Volume - 33 Gal (125 L)
Figure 13 RECYCLER/HEATER PHYSICAL DIMENSIONS
27
-------
Figure 14 PROCESS TANK WITH HEAD REMOVED
-------
the condenser shell to measure compressor discharge temperature,
T2-
During the evaluation test program in or-der to prevent the
carry-over of foam through the compressor it was found convenient
to add an entrainment control medium inside the processor tank.
This material is packed into the annulus formed by the evaporator
shell I.D. and condenser shell O.D. The assembly is shown in
Figure 15.
Components and Controls
Except for the weldment assembly, condenser coil and spray
ring assemblies, and compressor relief valve which were designed
by CHEMTRIC, all the system components were off-the-shelf type
purchased items. These components were selected for industrial
grade quality and availability throughout the country. Figure
16 is a schematic arrangement of the system in which all the pur-
chased parts are identified by numbered bubbles. These numbers
refer to the component descriptions given in Table 1. In Figure
17 an electrical schematic identifies the control components.
In the evaluation test program, described in Section VI, the sump
level control and storage tank pressure control were not used;
also, an interlock between the compressor motor and storage tank
heater was not used. The purging circuit arrangement, and con-
densate pump operation, as shown in Figure 16 was the result of
development efforts during the evaluation test program. Refer-
ring to Figures 16 and 17, for home use the system would operate
as follows.
From a wall-mounted circuit breaker, single-phase power (115
VAC, 20A 60 HZ) is brought to a terminal box located on the weld-
ment assembly (upper left center in Figure 11). When the cireuit
breaker is closed the water heater will be "on" whenever the sto-
rage tank temperature is below 160°F, provided the compressor is
not "on". The recycle pump will be "on" provided the wastewater
level in the sump is above the feed line, and the storage tank
pressure-is below 42 psig. Operations of the recycle pump pro-
vides fluid power for the jet pump which continuously purges the
condenser of air and other non-condensible gases. Discharge from
the jet pump, 2.5 gpm, is directed into the feed sump, where the
gas phase is readily separated from the liquid phase at atmo-
spheric pressure. Whenever the liquid level in the processor tank
is reduced by one inch, a solenoid-operated pinch valve is actu-
ated which allows wastewater from the sump to enter the processor.
When the jet pump evacuates the processor tank to 21 inches HG
vacuum, a vacuum switch is actuated. From a "cold" start, that
is, the processor is initially at atmospheric pressure and the
wastewater is aerated; approximately 1% hours is required to
reach operating vacuum pressure. Actuation of the vacuum switch
turns "on" the compressor. Then the condensate pump is con-
trolled by a differential pressure switch which turns "on"
the pump when the product water column in the condenser reaches
29
-------
Reticulated Fibrous Pellets -
( Beco Engineering Company )
Figure 15 SKETCH SHOWING DEMISTER LOCATION
30 inches, and turns "off" the pump when the column is lowered
to the suction line of the pump. This insures that the pump
suction is always flooded. Whenever the wastewater level in
the sump is too low and/or the hot water storage tank is filled
(pressure at 60 psig) the recycle pump and power to the com-
pressor and product pump are turned "off". Then a normally
closed pinch valve shuts off the flexible discharge line on the
jet pump in order to maintain the processor vacuum.
-------
Figure 16 ARRANGEMENT OF COMPONENTS AND CONTROLS
-------
Table 1 COMPONENT IDENTIFICATION
Item No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Description
Source
Condenser Tube Ass'y
Rotary Lobe Compressor
Weldment Ass'y
Vacuum Switch
Vacuum Gauge
Ball Float Check Valve
Jet Pump
Reverse Acting, Hydraulic
Actuated Pinch Valve
Float Control Ass'y
Lint Filter
Shut-Off Valve
Spray Ring Ass'y
Shut-Off Valve
Shut-Off Valve
Liquid Level Control
"Y" Strainer
Solenoid Actuated Pinch
Valve
Centrifugal Pump
Pressure Gauge
Differential Pressure
Switch
Rotary Vane Pump
Shut-Off Valve
Check Valve
Shut-Off Valve
Pressure Switch
Heater Control
Dormont Mfg. Co.
Gardner Denver
CHEMTRIC, Inc.
Square-D-Co.
U.S. Gauge Co.
CHEMTRIC, Inc.
Penberthy
CHEMTRIC, Inc.
Square-D-Co.
CHEMTRIC, Inc.
Apollo Valve Div.
Dormont Mfg. Co.
Apollo Valve Div.
Apollo Valve Div.
Magnitrol Div.
Paget
Trombetta Corp.
Worthington Inc.
U.S. Gauge Co.
Square-D-Co.
Procon Inc.
Apollo Valve Co.
Bivco Valve Corp.
Apollo Valve Co.
Square-D-Co.
Chromalox
32
-------
Figure 17 RECYCLER/HEATER ELECTRICAL SCHEMATIC
-------
SECTION VI
EVALUATION TESTS
Development tests and extended water quality evaluation
tests were conducted on the prototype water Recycler/Heater
unit shown in Figures 10 and 11. The primary objectives of
these tests were (1) an evaluation of the overall mechanical,
hydrodynamic and thermodynamic performance of the system, (2)
a determination of the physical, chemical and biological char-
acteristics of the recovered water, and (3) an evaluation of
the dependence of water quality on liquor, concentration. The
tests were conducted in two phases with two very different
waste streams. The first phase was a 38-day test series using
real laundry water. The second phase was a 21-day test series
using a synthetic wastewater stream which simulates concentrat-
ed hospital wastewater. This section presents a detailed des-
cription of the apparatus and test procedures used, and the re-
sults of water quality analyses and system performance measure-
ments.
Real Laundry Water
For these tests real laundry water was obtained by washing,
in a semi-automatic Kenmore washing machine, soiled clothes
supplied by CHEMTRIC employees. Seven employees participated
in the tests. The clothes could generally be classified as
"old clothes" such as work shirts and pants, children's play
clothes, laboratory coats, throw rugs, cleaning rags, furniture
covers, and drop clothes. A good supply of children's clothes
and underclothing were included since the homes of all the par-
ticipants contained young children. No attempt was made to
quantify the washing operation. However no complaints of a
"poor" wash were voiced by any of the participants' families.
The wash load during the tests varied from 4.0 Ib to 12.60 Ib
with an average value of 7.15 Ib (3.2 kg). A 30 gallon (114
liters) volume of water and 2.8 oz (80 grams) of FSN-7930-00-
634-3935 Type 1 cleansing agent were used for each load of soil-
ed clothing. Washing consisted of a single wash and rinse cycle,
each lasting from 1/2 to 1 hour, and each using 15 gallons (571)
of recovered water. The laundry soap was selected since lab-
oratory tests at CHEMTRIC indicated that it had a lower sudsing
level than the popular household detergents.
Test Apparatus
A schematic of the test set-up is given in Figure 18. The
34
-------
tn
INSULATION
CABINET
PHASE SEPARATOR
LAUNDRY WATER
PUMP
STATION
#3
KENMORE SEMI-AUTOMATIC
WASHING MACHINE
STORAGE TANK
LEVEL GAUGE
STATION
#2
STATION
figure 18 REAL LAUNDRY WATER TEST ARRANGEMENT
-------
external recycle loop consists of the Recycler, the washing
machine, and a laundry water pump. Each test-day consisted of
a single test run in which a single load of clothes was washed
using stored product water from the Recycler; then the waste
laundry water was returned to the Recycler for reprocessing.
Processing data were recorded at regular time intervals during
each run, and all the data referenced to hours into the run.
Regarding the washing operation, the load weight, amount of soap
and anti-foam additives, and the amount of make-up water (tap
water) were recorded. At the locations indicated in Figure 18,
the variable temperature field was recorded with a Honeywell
Electronik IS-point strip-chart recorder which measured the emf
generation from type T thermocouples. The evaporator and con-
denser saturation temperatures were obtained by measurements of
the saturation pressures PI and ?2> relative to the local atmos-
phere, using Meriam mercury manometers. These pressure measure-
ments also provided the AP across the compressor and the com-
pressor compression ratio. Total power input to the processor
was measured with a Simpson panel wattmeter; power and pressure
measurements, recovery rate, recycle pump pressure, and the am-
bient temperature and local barometer were also recorded. Pump
pressure was measured with a Helicoid, 0-30 psig, test gauge, and
recovery rate was determined with the use of a calibrated sight
glass tube mounted to the storage water tank; changes in water
level per 1/2 hour interval were recorded.
Referring again to Figure 18, at stations 1, 2, and 3
water samples were taken of the raw condensate, stored conden-
sate (product water), and concentrate (recycle liquor), respec-
tively. The condensate samples were taken through 5/8-inch di-
ameter rubber septums (Hamilton). Via these samples the phys-
ical, chemical and biological characteristics of the product
water were monitored during each test run. Resistivity was mea-
sured with a YSI Model 31 Conductivity Bridge; turbidity was
measured with a Hach Laboratory Turbidimeter, Model 2100A; the
pH of the product water was measured with a Corning pH meter,
Model 7. The daily build-up in concentration of dissolved solids
was measured using equipment and procedures specified in Standard
Methods for Examination of Water and Waste Water, Am. Pub. Health
Assoc., 13th edition. A Voland Model 220-D analytical balance
was used for weight measurements. Biological conditions were as-
sessed by positive-negative tests for sterility. Using sterile
sampling apparatus, one ml of sample water was added to each of
three tubes of Fluid Thioglycollate Medium (Scientific Products
Cat. No. 21195), and the resulting broth incubated at least 48
hours. Chemical conditions were assessed daily via COD deter-
minations. The equipment and procedures were those specified in
"Standard Methods". Near the end of the test series a detailed
chemical analysis of product water samples was conducted by the
Nalco Chemical Company, Analytical Services Division. These
tests were conducted for organics, metals, and ions.
36
-------
Test Procedure
In the first day's test 114 liters of tap water from the
storage tank was.pumped directly into the sump for processing in
order to establish a baseline; the recycling of waste laundry
water commenced the second test day. Referring to the test sche-
matic in Figure 18, the day-to-day test procedure was as follows.
At the beginning of each test day at 0800 hours product water
from the storage tank was gravity fed into the washing machine to
begin the wash cycle. The quantity used was determined by drain-
ing the tank to a level marked position "B" on the liquid level
sight gauge. Make-up water (tap water) was then added directly
to the machine; the amount of make-up was determined by the dif-
ference between the water level at the end of the previous test
run and a level marked position "A" on the gauge. The volumetric
difference between levels "A" and "B" was 57 liters.
Upon completion of the wash cycle the waste laundry water
was pumped into the feed sump of the Recycler, and the processor
turned "on" - that is, the recycle pump, compressor, and conden-
sate pump were started via a panel switch. This occurred at
0900 hours and marked the beginning of the test run, and a water
sample was taken from the storage tank at station #1. From this
point of time into the run, operational conditions, pressures,
temperatures, power and recovery rate were monitored at 1/2 hour
intervals. After the processor had been running for 1/2 hour to
2 hours an additional 57 liters of product water from the storage
tank was fed into the washing machine for the rinse cycle. Upon
completion of the rinse cycle the clothes were passed through the
machine's wringer rolls, then manually wrung to minimize the
make-up water requirement. The waste rinse water was then pump-
ed into the feed sump.
After 4 hours into the run at 1300 hours a water sample of
the raw condensate was taken -at station #1. Near the end of the
run, typically at 1430 hours a sample of concentrate was taken
at station #3. Termination of the run was determined, and the
processor turned off via the panel switch, when the sump level
was lowered to a marked position on a sight gauge (slightly above
the feed line). When this occurred the calibrated level gauge
on the storage tank indicated the total wastewater processed dur-
ing the run. The difference between this quantity and 114 liters
was the make-up water requirement for the next test run. When
the processor was turned off, the thermostatically controlled
heater in the storage tank remained "on" in order to maintain tem-
perature between runs. Typically, cooling of the processor tank
occurs between runs. This cooling caused a drop in the absolute
pressure so that the next run always began with the processor at
a higher vacuum level corresponding to the saturation pressure at
the lower,temperature.
37
-------
Test Results
Quantitative information was obtained throughout this test
series to establish both quality of the product water and mechan-
ical performance of the system. The analytical results on water
quality are presented in Tables 2 and 3. Table 2 represents the
results of daily in-house analyses performed by CHEMTRIC, while
Table 3 contains the results of detailed analyses for trace
metals and other chemical substances performed by Nalco Chemical
Company on water samples taken near the end of the test series
(test run #32).
The data presented in Table 2 are grouped according to con-
secutive days on which testing was performed. The blank lines
indicate days on which testing was not performed - because test
personnel were not available, or time was required to change the
testing arrangement.
After the fifth test day into the series foam formation be-
came a problem as evidenced by the sharp increase in turbidity
of the raw condensate. As the stored condensate was mixed with
raw condensate its turbidity began to rise; this trend continu-
ed for the next eight test days through the thirteenth test run.
At the end of this run an antifoam agent (Union Carbide SAG 470
Silicone Antifoam) was mixed into the recycle liquor at a concen-
tration of 0.161. Then, subsequent test runs included antifoam
additions to the wash cycle at the amounts indicated in Table 2.
These amounts represent concentration per 30 gallons (114 liters)
which are very low for the 16 grams dosage to medium for the 160
grams dosage - according to the manufacturer's suggested starting
concentration.
The final five test runs were conducted without the use of
any antifoam additive; instead, an entrainment control medium or
demister was installed within the processor tank as shown in
Figure 15. The data indicates that water quality remained
stable. It is noteworthy that the physical characteristics of
the stored condensate or product water at the end of the test
series are nearly identical to the original tap water in the
storage tank on the first test run. The COD, however, increased
from a value below 10 mg/1 to 60 ml/1 on the last test day. As
evidenced by continuing negative results from the sterility tests,
the product water remained sterile throughout the test series.
Physical characteristics and the COD of the concentrate and
feed stock were determined during test runs 27 and 28 respective-
ly; these are presented in Table 4. Referring to the feed
stock, a 1:1 mixture of used wash and used rinse water, the COD
of the product water represents a 90% reduction - that is, from
600 ppm to 60 ppm. Referring to the concentrate, the reduction
is 99.61. Both the feed and concentrate are alkaline, having a
pH of 9+.
38
-------
Table 2 LAUNDRY TEST DAILY ANALYSES
CM
1C
Test
Code*
01--'
02-A
03-V
04-B
05-A
06-V
07-W
08-A
09-V
10-B
11-P
12-A
13-W
14-B
15-V
16-P
17-W
18-B
19-A
20-V
O1 "\T
Wash
Load
(kg)
0.0
3.8
2.5
4.0
3.3
2.9
5.2
5.7
3.0
3.2
3.2
3.2
4.5
3.4
2.9
3.3
3.1
3.4
3.6
4.0
O 7
Make
-Up
0
4
5
9
10
24
0
0'
13
10
18
10
10
10
10
0
10
3
3
7
•z
Anti Total S Sterile
Foam (g/1) (+/-)
HL
0
0
0
0
0
0
0
0
0
0
0
0
208
16
16
80
80
80
80
80
on
S-2T S-3 S-l S-2
.073
.023
.027
.057
.025
.018
.030
.181
.143
.308
.216
.310
.371
.571
.398
.601
.307
.196
.101
.107
f»TC
Oc
1 A
1 R -_- _ _ _
9 -l ___ ___
9 Q
22
4.4 NST= ---
4.3
6n
A Q
51
7.3
7 f. j,
8.6
NST NST ---
ID 1 __-
in ft _ _ _
nc. _ _ _ _ _ _
12.5
13.4
17 C ___
pH Turbidity
(units) (Jtu)
S-l
NST
7.5
7.6
8.0
7.9
7.5
NST
7.7
7.2
6.8
8.6
8.0
7.9
7.1
NST
7.1
6.7
6.9
6.9
6.9
7 9
S-2
7.1
7.3
7.3
7.5
7.5
7.4
7.4
8.5
8.0
8.2
8.1
8.2
8.3
8.3
8.3
8.4
8.0
8.0
8.2
7.6
7 Q
S-l
2
3
4
5
3
40
NST
110
160
21
170
170
230
7
100
6
4
4
5
4
c
S-2
10
10
9
6
7
9
20
72
.70
125
120
130
150
230
155
245
130
86
55
35
xn
Sp. Res.
(kohm-cni)
S-l
NST
45
81
76
45
18
NST
7
6
15
5
4
3
16
NST
10
18
16
20
15
1A
S-2
9
12
16
18
19
19
17
9
9
6
7
5
5
4
5
4
5
7
8
10
i n
COD
Cmg/1)
S-l
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
MCT
S-2
10
10
20
10
34
14
30
75
95
45
175
195
315
800
440
964
275
308
175
115
An
See Notes On Next Page
-------
Test
Code
22-A
23-B
24-W
25-V
26-A
27-A
28-B
29-W"
30-B
31-A
32-V
33-J
34-A
35-R
36-V
37-B
38-R
Wash
Load
(kg)
2.8
3.1
2.3
3.6
2.7
2.8
2.9
2.7
2.6
3.1
2.4
5.2
1.8
3.6
2.3
2.3
3.4
Make
-Up
(1)
6
8
5
10
8
10
12
5
3
4
5
10
0
12
3
10
0
Anti Total S Sterile
Foam (g/1) (+/-)
LsL
80
80
80
80
240
160
160
160
160
160
160
160
0
0
0
0
0
S-2
.056
.022
.030
.032
.016
.409
.274
.122
NST
NST
NST
NST
.023
NST
.017
.020
NST
S-3 S-l S-2
1/17
1 A ft
15.5 -
-\ A Q
15.1
17.9
18.6
17 7
18.6 NST NST
21.5
1 7 ft ~
7fi Q _ _ _
23.5
7T Q ___
7/1 r
NST
25.3
pH Turbidity
(units) (Jtu)
S-l
6.9
6.7
7.1
7.1
7.4
7.2
7.5
8.1
7.0
7.3
6.9
6.8
7.3
6.8
7.1
6.6
6.9
S-2 S-l
7.8
7.8
7.6
7.9
7.9
8.2
8.3
8.0
NST
8.0
7.7
7.1
7.4
7.5
7.5
7.2
7.2
5
6
6
6
8
8
7
1
7
7
2
6
6
6
7
6
6
S-2
21
15
13
10
8
160
100
66
NST
27
20
21
32
21
17
14
10
Sp. Res.
(kohm-cm)
S^I S^2
13
16
13
13
13
16
15
17
11
20
10
11
14
11
10
14
8
10
10
10
10
11
4
6
8
10
10
10
10
10
10
10
9
8
COD
(mg/1)
S-l
NST
NST
NST
NST
NST
NST
NST
NST
NST
NST
55
40
60
65
70
60
60
S-2
95
85
70
60
55
966
250
155
NST
NST
NST
NST
NST
NST
NST
NST
NST
* Code refers to family whose clothes were washed during test
+ S-l, S-2 § S-3 refer to sample points (see figure 18).
# Test No. 01 was conducted with tap water.
= NST refers to No Sample Taken.
- Sample S-l on Tests No. 29 § 32 was drawn through a 25 ju filter,
-------
Table 3 LAUNDRY TEST NO. 32 DETAILED ANALYSES
Item Measured* Limit
Metals:
Barium(Ba), Soluble § Insoluble 0.5 mg/1 1.0 mg/1
Cadmium(Cd), " " " 0.01 " 0.01
Chromium(Cr), Hexavalent 0.1 " 0.05
Copper(Cu), Soluble § Insoluble 0.04 " 1.0
Iron(Fe), " " " 0.1 " 0.3
Lead(Pb), " " " 0.1" 0.05
Magnesium(Mg), Soluble § Insoluble 0.02 " NS"
Manganese(Mn), " " " 0.05 " 0.05
Silver(Ag), " " " 0.04 " 0.05
n
n
it
M
It
II
II
Other Parameters:
Ammonia(N) ( 16.0 mg/1 NS
Arsenic(As), Soluble § Insoluble 0.001 " 0.05 mg/1
Chloride (Cl) 2.0 " 250. "
Cyanide(CN), Free § Combined 0.01 " 0.2 "
Fluoride(F), " " " 0.05 " 0.8
Methylene Blue Active Substances 0.12 " 0.5 "
Nitrate(N) 0.2 " 45. "
Phenols(Phenol-C6H50H) 0.42 " 0.001 "
Selenium(Se), Soluble § Insoluble 0.002 " 0.01 "
Sulfate(S) 2. " 250.
Total Organic Carbon 20. " NS "
* Measured by Nalco Chemical Company.
+ U.S. Public Health Service Drinking Water Standards, 1962.
= Not Specified.
41
-------
Results of the Nalco chemical analysis for metals, ions, and
organics, and the physical properties determined by CHEMTRIC on
water samples from test run #34 are presented in Table 3. These
data represent the quality of the product water .with the process-
or operating at a 2% solids concentration, and a water recovery
of 96.31.
At the end of the test series on the 38th test day the %
solids had increased to only 2%% (2.53 x 104 mg/1), and the final
water recovery was 96.8%. Substantially higher concentrations
could have been achieved if more funds were available for testing.
Regarding the mechanical performance of the Recycler sys-
tem during this test program, Tables 5, 6, and 7 present the var-
iations in system temperatures, pressures, power, and recovery
rate. These parameters are presented as time dependent variables
in test runs 2, 20, and 38 respectively - that is, for runs at
the beginning, middle, and end of the test series. The tempera-
tures and pressures were recorded at the positions indicated in
the schematic of Figure 18.
States TI § PI and TS § ?2 are the saturation conditions in
the evaporator and condenser, respectively; it is assumed that
the non-condensible gases exert a negligible partial pressure.
Temperature T2 is the compressor discharge temperature; temper-
ature TS is a measure of superheated vapor temperature at the
entrance into the condenser shell, just downstream of the trans-
fer pipe exit. Temperature T4 is a measure of the ambient tem-
perature of the compressor drive motor in the vicinity of the
drive pulley approximately 1-inch from the belt surface. Temper-
ature Ty indicates the wastewater temperature in the feed sump as
it enters the processor. Temperature Tg is the environment tem-
perature within the insulated enclosure in the vicinity of the
recycle pump motor - and temperature Tg is the storage tank tem-
perature which is thermostatically controlled. Hence, for a
thermostatically controlled temperature Tg, temperatures T^
through Ty gradually increase with time during the run.
Table 7 shows that on the last test day, with the Recycler
operating at a solids concentration of 2.5%, 110 liters of water
was recovered during a run time of 5 hours, 25 minutes. This
sets the average recovery rate at 20.3 liters/hour (5.4 gal/hr).
During the process the average power draw was 1773 watts, which
sets the total energy consumption at 9.6 kw-hrs. Therefore the
specific energy consumption was 87 watt-hours per liter (330 watt
-hours per gal). It is seen that the specific energy was lower
and recovery rate higher at the end of the test series than at
the start of the series. This can be explained by the operation-
al variations between the test runs. These variations were the
different set points used to control the storage tank temperature
Tg and variations in purging technique. At the start, run #2,
the storage tank temperature was set at 170°F. During the course
of the tests, the set point was reduced to 160°F, and finally to
42
-------
Table 4 LAUNDRY TEST FEED AND CONCENTRATE
FEED - TEST NO. 28
Item Value
Total Solids 1.39 s/liter
Specific Resistance 3,700 ohms-cm
pH 9.1
Turbidity , 320 Jtu
Chemical Oxygen Demand 600 ing/liter
CONCENTRATE - TEST NO. 27
Item Value
Total Solids .., 16.0 g/liter
Specific Resistance 310 ohms-cm
pH , 9.4
Turbidity 5,400 Jtu
Chemical Oxygen Demand .15,000 mg/liter
43
-------
Table 5 PERFORMANCE DURING LAUNDRY TEST No. 2
Time
Chr)
ns^n
u oo u
0900
0930
1000
1030
1 1 nn
J- J.UU
1130
1200
1230
1300
1330
1 A f\ f\
1400
1 A 1f\
T-l
1J.fi
Jit D
140
142
144
147
i ^n
J. JU
153
155
158
161
162
1 £. A
lo 4
i fi£
1-2
162
168
174
182
_ _ ..
181
187
191
194
196
H M K
Tern
T-3
1 fi?
J.D L
149
152
155
159
1 f. 9
J-O L
166
167
169
172
171
1 7 *Z
1 / J
1 7d
perat
T-4
146
150
155
160
161
155
156
158
176
ures ,
T-5
150
152
156
170
182
184
169
174
180
0F
T-6
94
125
128
131
132
133
134
134
135
T-7
141
140
138
147
149
148
157
161
160
T-8
168
171
173
171
173
172
171
171
171
Press
(in. F
P-l
6Q9
. y^
5.92
6.12
6.52
7.11
7 >;fi
/ . ou
8.16
8.68
9.10
9.80
10.00
1 n fin
1U . DU
1 1 nn
;ures
Ig abs)
P-2
9Q7
. y L
7.42
7.92
8.62
9.32
i n nfi
-LU . UU
10.96
11.28
11.90
12.70
12.40
i 7 sn
x/. . ou
i ^. ?n
Total
Power
(kw)
9 nn
L , (JU
1.50
1.52
1.56
1.60
1 fi R
-L . D J
1.70
1.75
1.75
1.75
1.68
1 fiR
1.00
1 74
Recovery
Rate
(1/hr)
Q+- n-r- +
o tar L
6
16
16
20
18
24
16
22
20
16
24
22
Fnrl
-------
Table 6 PERFORMANCE DURING LAUNDRY TEST No. 20
tn
Time
(M
n o-zn
u o o u
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1420
T-l
1 ^
-LOO
130
132
135
138
140
143
145
145
148
150
151
151
T-2
142
150
154
160
163
165
171
172
177
179
181
182
Tern
T-3
140
143
145
147
150
151
154
156
158
160
162
162
perat
T-4
131
132
141
147
148
151
157
159
164
164
167
150
ures ,
T-5
143
144
148
159
155
157
155
157
162
164
163
163
0F
T-6
114
118
122
125
123
127
128
129
130
T-7
135
138
140
142
138
140
145
146
149
150
149
142
T-8
161
159
159
159
158
157
158
158
159
159
159
159
Press
(in. I
P-l
4.50
4.80
5.10
5.52
5.92
6.32
6.72
6.72
7.22
7.52
7.82
7.82
>ures
Ig abs)
P-2
4
5.90
6.30
6.60
7.02
7; 52
7.72
8.30
8.72
9.32
9.72
10.02
10.02
Total
Power
(kw)
1.50
1.50
1.50
1.50
1.50
1.50
1.55
1.60
1.60
1.65
1.70
1.70
Recovery
Rate
(1/hr)
S
16
16
14
18
24
24
18
24
24
22
16
End
-------
Table 7 PERFORMANCE DURING LAUNDRY TEST No. 38
ON
Pressures
Time
(hr)
0900
0930
1000
1030
1100
1130
1200
1230
1300
1330
1400
1425
Temperatures ,
T-l
128
131
135
141
144
148
151
153
155
158
160
160
T-2
• — —
153
161
170
175
182
185
189
191
196
199
202
T-3
141
142
146
152
156
161
163
164
168
170
172
172
T-4
139
146
155
160
168
170
172
176
181
182
172
T-5
151
162
167
168
174
164
166
167
172
174
176
oF
T-6
140
151
157
161
162
154
161
164
170
(in. Hg abs)
T-7
138
141
143
146
144
142
.
150
151
156
150
151
T-8
156
155
155
155
154
151
150
150
151
153
156
P-l
4.22
4.62
5.20
6.00
6.50
7.20
7.70
8.20
8.50
9.20
9.60
9.60
P-2
6.12
6.22
6.92
8.00
8.80
9.80
10.30
10.60
11.60
12.30
12.90
12.90
Total
Power
(kw)
1.69
1.60
1.60
1.65
1.70
1.78
1.80
1.84
1.87
1.90
1.90
Recovery
Rate
Cl/hr)
Start
10
18
24
16
20
20
26
20
24
26
20
End
-------
155°F. The higher feed temperatures in run #2, resulting from
the higher set point Tg, lowered the temperature difference be-
tween inlet and outlet liquor through the heat exchanger. This
reduced the recovery rate and lengthened the run time.
The low specific energy obtained in run #20, 77.0 watt-hours
per liter (291 watt-hours per gal), was the result of good purg-
ing of the non-condensibles from the condenser. With good purg-
ing, low pressure differentials, £P, across the compressor can
be maintained; therefore, the compressor shaft power is lower.
These results were characteristic of runs 16 through 28 wherein
the purge circuit was arranged as shown in Figure 19. The dif-
ference in this arrangement from the previous test runs is the
addition of a vapor trap or condenser upstream of the" needle
valve. The condenser was formed from a 10-foot section of 3/4-
inch diameter copper tubing into the shape shown in Figure 19,
and mounted on the outside of the rear insulation panel. The
condenser increased the air/vapor ratio entering the jet pump and
effectively increased its purging capacity.
For test runs 30 through 38 a transfer tube was assembled to
the jet pump discharge. This tube is shown in phantom in Figure
19. It was anticipated that the transfer tube would further im-
prove the purging effectiveness. However, higher pressure dif-
ferentials across the compressor were obtained after the transfer
tube addition. This indicated that the tube diameter was too
small causing a back pressure on the jet pump resulting in mar-
ginal purging performance.
It is noteworthy to compare the temperatures TS and TS in
Tables 5, 6, and 7. It is seen that temperature T$ is very close
to the saturation temperature T3. This indicates that the water
droplets dripping off the condenser tubing effectively desuper-
heat the vapor as it enters the condenser shell. The degrees
superheat, T2-T3, is shown to characteristically increase with
time into the run. However, % superheat, defined as the change
in enthalpy (h2-h3) compared to the latent heat of condensation,
(hs-h4), at the saturation temperature, TS, remains small. The %
superheat gradually increases to 1% at the end of the run. With
the purging technique used in Run #20, the % superheat is smaller,
and does not exceed 0.81.
Synthetic MUST Brine
The second test series was performed using a synthetic waste.
Since real wash water has a relatively low solids concentration,
on the order of 1000 mg/liter (0.1%), a synthetic waste was re-
quired in order to evaluate the processor at high solids concen-
tration within a reasonable test period. For this purpose the
synthetic Medical Unit, Self-contained, Transportable (MUST) hos-
pital composite waste was used at a concentration of 20X, which
simulates the brine from an ultrafiltration and reverse osmosis
system. The chemicals used to prepare 30 gallons of 20X MUST
47
-------
WATER VAPOR TRAP
LOCATED OUTSIDE CABINET
NEEDLE
VALVE
TO CONDENSER
COIL
JET PUMP
PURGE GAS FROM
CONDENSER SHELL
RECYCLE LIQUOR
FROM EVAPORATOR
Figure 19 JET-PUMP PURGING ARRANGEMENT
48
-------
hospital composite waste each day were supplied by the Walden
Research Division of Abcor Incorporated. The" formulation is pre-
sented in Table 8; this brine has a solids concentration on the
order of 21.
Walden prepared the MUST constituents into twenty separate
boxes - that is, each box contained the chemicals needed for 30
gallons of 20X solution so that at the end of the twenty test
days the processor could be evaluated at a near 30% solids con-
centration. In Figure 20 is a photograph which shows the chem-
ical groups corresponding to the constituents in Table 8 used to
prepare the waste stream for each test run. The mixing proce-
dure is presented as follows:
Group I -
Group I components are all solids. They were weighed-out
together and mixed in first. These components were prepared by
Walden with the exception of the human hair. The hair was ob-
tained from a local barber shop and placed into plastic bags for
storage until used.
Group II -
Group II components are liquids and gels. They were weigh-
ed-out together and mixed in seconds. This group was prepared
entirely by Walden.
Group III through IX -
These components are all liquids. They were weighed-out
in their respective groups except for the dichromate cleaning
solution which was measured out separately and refrigerated.
Chemicals which were weighed-out together were added to the
waste stream in a random order.
Group X -
Group X components are gels and solids. The agars were ob-
tained from Walden, prepared as gels, mixed together, placed in
plastic containers and refrigerated.
Beef blood was obtained fresh, with sodium citrate added,
from a local butcher. It was placed in plastic containers and
refrigerated.
Dog food was obtained from Walden. It was weighed in plas-
tic bags and refrigerated.
Urine was obtained daily from lab personnel, and refrigerat-
ed.
All components were added to the batch waste in random
order.
49
-------
Table 8 SYNTHETIC BRINE FORMULA
Group
1
Constituent
Concentration
4
Detergent, Type 1 (FSN 7930-634-3935)
Sparkleen
Haema-Sol (Non-Sudsing Detergent)
Sodium Chloride
Hair
Shower/Lavatory Cleaner
Hand Soap (Lava)
Scouring Powder (FSN 7930-205-0442)
Talc
Soil (Kaolinite)
Silver Chloride
Urea
Lysol (Undiluted)
Insect Repellent (DEBT)
Deodorant
Hair Dye
Hair Coloring
Hair Oil
Hair Gel
Toothpaste
Vegetable Oil
Grease (Lard)
Phisohex (Soap)
Hair Shampoo
Mouthwash
Betadine
Wescodyne
Dichromate Cleaning Solution
Methyl Alcohol
Acetone
Kodak X-Omat Developer
Kodak X-Omat Fixer
4420.
4040.
3940.
3260.
2280.
1010.
696.
442.
202.
192.
143.2
10.1
62.6
10.1
10.1
10.1
10.1
1516.
374.
374.
352.
234.
173.
50.6
20.2
3780.
712.
1258.
404.
125.8
18.84
18.84
mg/1
tt
it
it
ti
1!
II
tl
It
tt
tt
tt
ml/1
tt
it
tt
it
mg/1
tt
tt
tt
ti
ti
tt
it
mg/1
ti
Ail /I
ti
tt
ml/1
tt
50
-------
Table 8, Continued.
Group
5
Constituent
Concentration
Giemsa Stain
Wright Stain
Crystal Violet Stain
Saf ranin
Immersion Oil
Thioglycolate
Sodium Chloride
Zinc Sulfate
0.1 N Sodium Hydroxide
5% Phenol Solution
0-Toluidine Reagent
Phenol Color Reagent
Lithium Diluent
Biurent Reagent
Alkali-Hypochlorite Reagent
Buffered Substrate
10% Formaldehyde
KI-I Solution
22.2% Sodium Sulfate
3% Sulfosalicylic Acid
Bilirubin Standard
301 Thichloroacetic
2% Sodium Citrate
Diazo Reagent
DNPH Color Developer
Ether
Suspended Solids (Dog Food)
Urine
Blood (Animal)
Blood Agar
Chocolate Agar
EMB Agar
Agar
Spinal Fluid
150.
138.2
25.2
25.2
12.58
628.
604.
414.
454.
314.
69.2
37.6
37.6
31.4
25.2
25.2
25.2
25.2
25.2
25.2
25,2
18.82
12.58
12.58
12.58
12.58
2800.
4260.
3660.
414.
414.
414.
232.
12.58
Ail/1
ii
"
11
it
,18/1
II
Lll/1
ti
it
li
il
it
it
tt
tt
it
it
it
it
tt
ii
tt
ll
it
mg/1
pl/1
ti
it
M
It
II
II
51
-------
01
r J
rj
C H£ •• i '
Figure 20 DAILY SYNTHETIC BRINE INGREDIENTS
-------
Spinal fluid was not added since it was impractical to ob-
tain from local hospitals. Also, after the second test run dog
food and hair were not included in the waste stream formula,
since these ingredients were effectively removed by the lint fil-
ter in the sump (see Figure 19 and Table 1).
Test Description
To initiate the test series the recycle loop and storage
tank were filled with tap water, 131.8 liters and 263.1 liters,
respectively. Thus, in the first day's test run tap water from
storage was fed directly into the sump for processing in order
to establish a base line. A run of three hours was conducted for
this purpose.
Recycling of 2OX MUST wastewater commenced on the second
test day .and continued for twenty test days. No additional tap
water was added throughout the test series, nor was any antifoam
agent added.
The twenty test days with the synthetic brine can be class-
ified into seven modes dependent primarily on the preconditioning
of the feed stock. These classifications are identified in Table
9. For modes 1 and 2 the test set-up is shown in Figure 21. The
20X MUST constituents were mixed with recycled product water to
make a 30 gallon solution within a calibrated polyethylene con-
tainer and pumped directly into the sump for processing. For the
remainder of the tests, modes 3 through 7, the test set-up is
shown in Figure 22. In this arrangement the storage tank was
used as a preconditioning chamber. The feed stock solution from
the polyethylene tank was pumped directly into the storage tank
the evening previous to each test day. The storage tank was
maintained under vacuum pressure via a peristaltic pump which
continuously purged the evolved gases for a period of 12 hours
or more between test runs. Modes 3 through 7 are distinguished
by different set point temperatures of the thermostatically con-
trolled heater in the storage tank. As indicated in Table 9 pre-
conditioning temperatures of 160°F and 85°F were evaluated. In
modes 6 and 7, photochemicals (groups 4 and 5 in Figure 20) were
not added to the feed stock.
/
During each test run thermodynamic data was recorded regu.-
larly at % hour intervals - and daily water samples of the feed,
concentrate, and condensate were taken at specific times into the
run. In addition, hourly test tube samples were taken of the
product water during modes 3 through 7 in order to record varia-
tions in turbidity within each test run.
Near the end of the fifth test day (Mode 2), 5% hours into
the run, gross foam carry-over through the compressor occurred.
The unit was shut-down and subsequent start-up was prevented due
to a locked compressor rotor. Inspection of the compressor drive
also revealed gross deterioration of the motor insulation, and
53
-------
gross peeling-off of the paint on the motor and compressor frames.
Also, loose rust particles covered the surfaces of the compressor
drive mounting plates (condenser cover plate). The probable
cause of the rotor locking was rust particles entering the suc-
tion side of the compressor and wedging into the close clearance
between the rotary lobes. The compressor was easily freed on the
bench with a strap wrench applied to the drive pulley. No mech-
anical damage of the lobes or timing gears occurred. Before the
start of the next test run the compressor motor was rewound with
class H insulation (the original winding had a class F rating) and
the test set-up was rearranged as shown in Figure 22.
No further foam carry-over was evident for the remainder of
the test series, consecutive test runs 6 through 21. However, on
the last test day, run #21, near the end of the test approximate-
ly six hours into the run another compressor drive failure occurr-
ed. Subsequent inspection revealed that the compressor rotor had
locked, and there was a short to ground in the motor winding.
Visual inspection of the motor, however, did not reveal any heat
deterioration of the stator insulation.
Test Results
The daily water analyses performed during the synthetic brine
tests are summarized in Table 10; these data were obtained in the
CHEMTRIC laboratory - except for the TOG data, which the Nalco
Chemical Company determined. The results of detailed analyses
performed by Nalco on raw condensate samples taken during runs 10,
15, and 18 are presented in Table 11.
The condensate total solids data presented in Table 10 in-
dicate that during the initial tests foam was being carried over
from the evaporator into the condenser. After the fifth test,
when the feed was always degassed overnight in the storage tank,
the turbidity data indicates that degassing eliminated or at least
reduced the foam carry-over problem. After the seventh test the
total solids data indicate that the problem had definitely been
eliminated or reduced to an insignificant level (i.e., TS <40 ppm
except for test #12). The condensate total solids level was still
high during tests #6 and #7 because the condenser had been contam-
inated during the previous test days by foam carry-over, and the
flushing action of fresh condensate during tests #6 and #7 was re-
quired to clean the condenser surfaces.
After the foaming problem was resolved by degassing the feed,
the specific resistance and the organic content of the condensate
were still excessively high. Reducing the degassing temperature
(i.e., increasing the vacuum) and finally eliminating the addi-
tion of fresh photochemicals did not improve the condensate qual-
ity. Instead, the quality continued to degrade - but this is at-
tributed to the fact that the concentration of solids in the con-
centrate (recycle liquor) was continuously increased during this
period from 0.05 to 0.293.
54
-------
Table 9 SYNTHETIC BRINE TEST MODES
Mode
On
On
6
7
Test Runs
1 thru 4
Description
6 thru 10
11 thru 15
16 thru 18
19 thru 20
21
Test set-up per Figure 21 - feed stock prepared
morning of test and added directly to sump -
no degassing.
Test set-up per Figure 21 - feed stock prepared
previous evening and heated in polyethelene tank
over night (250 watts) for 12 hours.
Test set-up per Figure 22 - feed stock prepared
previous evening and heated in storage tank
under saturation conditions - temperature set
point § 160°F.
Test set-up per Figure 22 and mode 3 - but
temperature set point § 135°F - door on cabinet
removed for entire test run.
Test set-up per Figure 22 and mode 3 - but no
power to storage tank heater - door and top
insulation panel removed for entire test run -
storage tank temperature at 85°F.
Test set-up per Figure 22 and mode 5 - but no
photo chemicals added to feed stock.
Test set-up per Figure 22 and mode 6 - but
temperature of storage tank maintained at 160°F.
-------
tn
ON
./- PHASE SEPARATOR
INSULATION CABINET
SUMP TANK LEVEL
GAUGE *—
STATION #1
STORAGE TANK
LEVEL GAUGE
STATION
#2
STATION
#3
CIRCULATING AND
FEED PUMP
'POLYETHELENE MIXING
TANK - MUST SOLUTION
Figure 21
SYNTHETIC BRINE TEST INITIAL ARRANGEMENT
-------
tn
-J
INSULATED CABINET
PERISTALTIC
PURGE PUMP
HOLDING TANK
LEVEL GAUGE
STATION
#1
FEED
SAMPLE
Nfc-i
'STATION
#3
TRAP
CIRCULATING AND
FEED PUMP
POLYETHLENE MIXING
TANK - MUST SOLUTION
Figure 22
SYNTHETIC BRINE TEST FINAL ARRANGEMENT
-------
Table 10 SYNTHETIC BRINE TEST DAILY ANALYSES
en
oo
Test
No. §
Mode
01-1
02-1
03-1
04-1
05-2
06-3
07-3
08-3
09-3
10-3
11-4
12-4
13-4
14-4
15-4
16-5
17-5
18-5
19-6
20-6
Total Solids
Feed
NST+
2.41 .
1.57 .
1.69 .
2.42 .
5.77 .
3.06 .
2. 78 .
.2.53 .
2.67 .
2.68 .
2.74 .
2.81 .
2.91 .
2.90 .
3.00 .
3.58 .
4.04 .
4.26 .
4.44 .
(*)
S-l*
NST
017
012
014
012
014
010
002
002
003
002
Oil
001
004
001
001
001
001
004
003
Sterile
pH
(+/-) (units)
S-3
NST
0.6
2.0
3.6
4.9
5.0
6.6
9.0
15.3
14.6
15.0
16.0
18.1
19.3
21.2
22.2
22.7
23.2
25.2
28.0
S-l S-2
NST NST
--- NST
--- NST
ii
n
ii
n
+-- NST
"
II
II
"
NST
ii
n
--- NST
M
S-l
5.6
8.9
9.0
9.3
9.3
9.4
9.4
9.6
9.7
9.6
9.6
9.6
9.4
9.4
9.4
9.1
9.1
9.4
9.4
9.1
S-2
NST
7.2
8.8
9.0
NST
NST
"
"
n
M
NST
n
n
it
n
NST
n
n
NST
tt
Turbidity
(JtuJ
S-l
4
16
18
20
25
10
10
12
16
11
6
8
8
10
10
10
12
10
10
11
S-2
NST
3
7
12
NST
NST
11
n
ti
n
NST
11
n
"
n
NST
n
it
NST
ti
Sp.
Res.
(ohm -cm)
S-l
NST
720
240
300
400
660
580
560
450
480
560
400
340
300
300
250
200
240
210
150
S-2
NST
3700
980
550
NST
NST
ii
n
M
M
NST
"
M
It
M
NST
tt
11
NST
it
COD ,
(mg/lxlO )
Feed
NST
20.0
21.0
19.0
22.0
24.0
29.5
26.5
26.5
2-5 . 5
27.5
26.5
24.5
24.5
26.5
24.5
36.5
39.5
38.5
43.0
S-l
0.1
0.9
<2.0
1.9
-1.0
1.4
1.1
* 2. 0
1.0
2.7
2.1
2.9
3.1
3.3
3.8
4.0
4.6
4.8
5.2
5,9
S-2
NST
0.1
0.6
1.0
NST
NST
it
it
"
ii
NST
ii
tt
n
n
NST
n
M
NST
it
S-3
0.6
6.0
16.0
25.0
37.5
34.0
57.5
72.5
114.
11-8.
142.
154.
150.
174.
190.
192.
206.
222.
224.
248.
TOG
Cmg/1)
S-l
NST
210
610
640
NST
360
470
700
870
720
550
740
970
2100
1000
2400
1400
1300
1500
1600
21-7 4.91 NST 29.3 NST NST 9.6 NST 17 NST 320 NST 48.0 4.4 NST 256.
* S-l, S-2 and S-3 refer to sample points (see figures 21 and 22).
+ No sample taken.
NST
-------
Table 11 SYNTHETIC BRINE TEST DETAILED ANALYSES
Item
Metals:
Barium(Ba) , Soluble § Insoluble
Cadmium (Cd), " " "
Chromium(Cr) , Hexavalent
Copper(Cu) , Soluble § Insoluble
Iron(Fe), " "
Lead(Pb), " " "
Magnesium(Mg) , Soluble § Insoluble
Manganese (Mn) , " " "
Silver(Ag), " " "
Other Parameters:
Ammonia(N)
Arsenic(As), Soluble § Insoluble
Chloride (Cl)
Cyanide (CN) , Free § Combined
Fluoride (F), " " "
Methylene Blue Active Substances
Nitrate(N)
Phenols (Phenol-C6H50H)
Selenium(Se) , Soluble § Insoluble
Sulfate(S)
Total Organic Carbon
Nalco
Test #10
'0.5
'0.01
'0.1
0.25
'0.1
'0.1
'0.02
<-0.05
'0.01
740.
'0.001
470.
'0.01
'0.05
0.22
'0.2
120.
'0.002
6.
720.
Measurements
Test #15
'0.5
0.01
'0.1
0.30
'0.1
0.1
0.02
'0.05
*0.01
1000.
'0.001
150.
'0.01
'0.05
0.38
'0.2
150.
'0.001
1.9
1000.
, mg/1
Test #18
'0.5
0.02
'0.1
2.8
0.2
'0.1
'0.02
'0.05
0.01
1400.
'0.002
1.
'0.01
'0.05
0.32
*0.2
160.
'0.002
3.
1300.
U.S. PHS
Limit
1.0
0.01
0.05
1.0
0.3
0.05
NS*
0.05
0.05
mg/1
"
"
"
"
"
"
"
NS*
0.05 mg/1
250. "
0.2 "
0.8
0.5
45.
0.001
0.01
250,
it
M
II
II
II
II
NS*
* Not Specified.
-------
Table 11 indicates that the condensate had a very strong
ammonia odor, and excessive amounts of chlorides and phenols.
The major source of these constituents was undoubtedly the
Kodak developer and fixer used to simulate wastes from an X-ray
film processor in a hospital laboratory. Thus, if these wastes
had not been added to the synthetic brine the quality of the
recovered water would have been substantially higher. Similar-
ly, if the pH of the feed had been adjusted to "fix" the am-
monia, the chloride and ammonia levels would have been near
acceptable values.
The high ammonia, chlorides and phenol levels do not ex-
plain the excessively high COD and TOG levels presented in
Table 11. Identification of the source of these organics was
undertaken by the Environmental Chemistry Branch at Fort De-
trick; their results are presented in Table 12, along with
the TOG determinations made by the Nalco Chemical Company.
As seen in this table, nearly two-thirds of the TOG is due to
organics which co-distill with water at the conditions pres-
ent in the Recycler/Heater. The other third is apparently
phenols and trace organics.
Identification of the condenser gases was attempted by
pumping a portion of the condenser purge gases into a sample
bottle, per the 5tandard Methods procedure for collecting
sludge digester gas, during one of the mode 3, 4 and 6 tests.
These samples were sent to All-Tec Associates in Arlington
Heights, Illinois for chromatographic determination of their
oxygen, nitrogen, methane, ammonia and carbon dioxide content.
The results obtained are presented in Table 13.
60
-------
Table 12
COMPARISON OF ORGANICS DETERMINATIONS
Test
No.
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
Fort Detrick Data, mg/1
Methyl Ethyl I sop ropy 1
Alcohol Alcohol + Acetone + Alcohol
112
251
244
--- No
170
219
269
403
305
270
388
420
449
548
627
713
755
738
447
40
113
105
64
84
107
129
116
94
155
190
165
169
226
281
326
357
334
7
66
50
Sample -- Taken
10
12
18
16
17
7
20
32
22
20
49
71
92
109
94
0
4
4
2
3
3
3
3
2
4
4
4
4
5
7
8
9
8
Sum
Total
159
434
403
246
318
397
551
441
373
567
646
640
741
907
1072
1181
1213
883
Nalco*
TOC
(mg/1)
210
610
640
360
470
700
870
720
550
740
970
2100
1000
2400
1400
1300
1500
1600
Fraction Identified by Fort Detrick = 0.615 = 11172 / 18140
* TOC Data Determined by Nalco Chemical Company
61
-------
Table 13 PURGE GAS ANALYSES
Test No. Oxygen Nitrogen Methane Undetermined
9 19.0% 77.5% 3.5% 0.0%
15 2.6 9.4 54.0 34.0%
20 Sample Bottle Broken In Transit --
The results obtained from the Test 9 sample were as expected -
because highly soluble gases such as ammonia should be absorb-
ed by condensate on the heat exchanger before the purge gases are
drawn from the condenser. Conversely, the large percentage of
methane and undetermined gases in the Test 15 sample was unex-
pected. Apparently, methane and other non-condensible gases were
being evolved in the storage tank - so that purge gases drawn
through the storage tank were diluted with these gases prior to
the sample bottle. In both cases, the volumetric flow rate of
non-condensible gases was relatively low - because the peristal-
tic purge pump which has a displacement of 1000 cc/min is cap-
able of maintaining the required condenser pressure.
Mechanical performance data during the MUST waste stream
tests are given in Table 14 and 15. Table 14 represents data
during Test #1 with tap water; Table 15 contains the data re-
corded during Test #21, which concluded the test series with a
total dissolved solids concentration of 29.3%. It is seen that
at the same operating temperature, TI, the recovery rate at 29.3%
solids is 30% lower than the tap water baseline rate.
Upon completion of the brine tests the flanged head was re-
moved and the compressor drive, relief valve, condenser cover
plate, condenser coil assembly, and spray ring assembly were re-
moved for inspection and cleaning. There was no mechanical dam-
age to any components; however two spray nozzles were complete-
ly plugged with lint material which was protruding into the 3/4-
inch diameter ring manifold. Hence, the lower recovery rate
feaseline can be attributed to nozzle blockage. The lint material
Mas evidently left-over from the laundry water tests and had ac-
cumulated in the nozzles to form a plug during the synthetic
brine tests.
62
-------
Table 14 PERFORMANCE DURING BRINE TEST No. 1
Time
Chr)
1500
1530
1600
1630
1700
1730
1800
Temperatures ,
T-l
137
140
141
144
148
T-2
168
171
174
181
184
184
T-3
146
149
154
157
161
T-4
154
155
159
164
166
167
T-5
155
155
159
162
165
168
op
T-6
140
144
147
142
Pressures
(in. Hg abs)
T-7
141
143
146
149
151
151
T-8
156
158
158
160
159
158
P-l
5.4
5.9
6.0
6.6
7.2
P-2
6.9
7.4
8.3
8.9
9.8
Total
Power
(kw)
1.40
1.45
1.60
1.70
1.70
Recovery
Rate
U/hr)
Start
16.0
16.0
16.5
16.6
17.5
19.2
End
-------
Table 15 PERFORMANCE DURING BRINE TEST No. 21
Time
(hr)
0940
1000
1030
1100
1130
1200
1230
1300
1330
1400
1420
* Cabinet
Temperatures ,
T-l
129
128
132
137
143
145
147
148
„ «. «
150
door
T-2
_ _ —
157
169
181
187
195
199
201
202
203
T-3
150
145
154
154
161
162
164
166
167
T-4
142
151
166
176
181
177
179
180
T-5
163
170
179
187
184
164
164
164
167
op
T-6
125
140
148
151
116*
101
103
107
107
Pressures
(in. Hg abs)
T-7
131
133
135
138
141
140
142
143
143
T-8
159
159
160
159
162
161
162
162
162
P-l
4.4
4.3
4.8
5.4
6.4
6.7
7.0
7.2
7.5
P-2
7.6
6.6
8.3
8.3
10.0
10.2
10.6
11.2
11.5
Total
Power
(kw)
1
1
1
1
1
1
1
1
_
1
-
.70
.53
.73
.54
.56
.52
.51
.55
_ _ _
.53
Recovery
Rate
d/hr)
Start
9.6
11.1
12.0
12.8
13.5
13.5
12.9
13.2
End
removed
-------
SECTION VII
DISCUSSION OF RESULTS
Design
The test results indicate that the processor tank tempera-
ture ranges from less than 165°F during standby (e.g., over-
night) to more than 165°F after several hours of continuous oper-
ation. This characteristic causes the "starting" recovery rate
to be lower than 6 gph - and the steady-state load on the com-
pressor motor to be too high. Future designs should include (1)
a standby heater in the process tank, if a fast start-up is re-
quired, and (2) less insulation or a thermostatically-controlled
cabinet-ventilation fan.
These tests have also demonstrated the need for a lint fil-
ter when processing real laundry wastewater. Long fibers tend
to coalesce and plug the spray nozzles (0.53 cm) in the evapora-
tor and the jet pump nozzle (0.31 cm). Also, for quick access-
ibility to the compressor drive, a V-retainer coupling flange in-
stead of the bolted flange used in the prototype design would
provide much easier and faster removal of the tank head; this
together with a thinner gage (12 gage) material for the head
would provide a lighter assembly weight, on the order of 25 Ibs
(11.3 kg). According to the manufacturer's recommended lubrica-
tion requirements the compressor drive should be inspected (hence
the head must be removed) every three months based on an 8-hour
day, 5 day per week operation of the Recycler.
Regarding the compressor motor, for long service life the
single phase capacitor start motor should utilize an external re-
lay instead of an internal centrifugal starter switch; this re-
lay could be located with the capacitor outside the compressor
tank. Also, the main motor winding insulation (i.e., the ground
insulation in the slots and wedges of the stator) should be Nomex
(DuPont); the strand insulation on the wire should be high-tem-
perature (220°C), polyamide resin material similar to Pyre-ML
magnet wire manufactured by Rea Magnet Wire Company; lead wire
insulation between coils should be a glass braid tape material.
This type of insulation system is not uncommon nor is it too
costly.
The importance of good purging technigue was clearly demon-
strated during this test program. Keeping the condenser shell
adequately free of air and other non-condensible gases results in
a low specific energy requirement, which is very close to that
65
-------
predicted by the analysis presented in Section 4. The predicted
power requirement was 1798 watts based on a recovery rate of 6
gallons (22.7 liters) per hour; this equals a specific energy of
79.2 watt-hours per liter. The measured values during laundry
water Test #20, in which an improved purge technique was used,
indicate that the average specific energy was 77.0 watt-hours per
liter. On the last test run, Test #38, with the processor oper-
ating at 2.5% total dissolved solids the average specific energy
is 10% higher than the predicted steady state value; however, as
explained in Section VI under Test Results, purging was marginal.
These tests have also shown that corrosion presents a prob-
lem, and corrosion resistant materials are required with the
MUST feed if degassing is not effectively accomplished. At the
higher processing temperatures required for higher recovery
rates, the chloride content in the ammonia chloride carry-over
increases and its reaction with water vapor to form hydrochloric
acid can be quite corrosive.
Water Quality
Since there are no published standards per se for wash water
it is necessary to refer to the 1962 Drinking Water Standards
published by the Public Health Service. This is done in Table 3
wherein the analytical data obtained from Laundry Test #32 is
compared to the Standards. The analytical data obtained from
Brine Test #10, 15 and 18 are presented in Table 11 for compar-
ison. It is seen that the product water from both the laundry
water and brine tests can be classified as soft since the total
solids content is well below 75 mg/1. Also, in both cases the
product water was sterile. Regarding the product water from the
laundry water tests, the water was clear but would not be consid-
ered potable due to the organic content of 20 mg/1 and ammonia
content of 16 mg/1. For use as wash water this order of magni-
tude of TOG should be harmless; also, the product water did not
have an objectionable odor due to the ammonia content.
Regarding the product water from the brine tests, though an
881 reduction in COD was achieved for example in Test #18, the
magnitude of TOC was still very high (1300 mg/1) due to the very
high organic content of the feed stock. The feed stock TOC was
not measured but its magnitude can be assessed by use of the ave-
rage CODrTOC ratio of 3.1 computed from sixteen values of COD and
TOC given in Table 10 for condensate samples (TOC values for
tests No. 14 and 16 were not used in the computation since these
were considered too high). Since the degassed feed COD was 39,
500 mg/1, the TOC value was on the order of 13,000 mg/1. The
turbidity of the feed was well beyond 1000 Jtu. The product
water was very clear in comparison having a turbidity of 10 Jtu;
however, it had characteristically a slight cloudy appearance and
a strong ammonia odor. It is interesting to point out that fixed
(acified to a pH of 2) samples of the product water stored in
quart jars sealed with aluminum foil became very clear in appear-
66
-------
ance and a spot measurement revealed a gross reduction in tur-
bidity to a value less than 1 Jtu. This was evidently due to
the gradual escape of soluable gases. Results of these tests
have indicated that the processor had concentrated the simulated
brine discharged from the MUST water treatment system to at
least 15X. A gross reduction of the TOC and ammonia in the re-
covered water, however, must be accomplished by a more effective
pretreatment of the feed stock such as extended aeration.
67
-------
SECTION VIII
ECONOMIC ASSESSMENT
The Recycler/Heater developed under this program reflects a
concern for design details that are required to achieve a steady
-state process rate of 22.7 liters/hr (6 gph) and a specific
energy draw of 79 watt-hours/liter, within a self-contained pack-
age which requires a minimum of floor space. During the test
phase, the operational conditions, control specifications, and
maintainence requirements were defined. With these data it is
possible to estimate the actual annual cost of this type of self-
contained water recovery appliance, and compare these costs to
water and disposal costs to predict the potential demand.
Total Annual Costs
Actual manufacturing costs are difficult to ascertain be-
cause they are dependent on production volume, facilities, equip-
ment, and experience. For the purpose of a cost projection, how-
ever, baseline costs were estimated by taking the confirmed Parts
List of the prototype assembly and soliciting quotations on each
component as a function of quantity purchased. This should pro-
vide an accurate baseline in today's dollars since most of the
components are purchased parts which are already production items.
It should be noted that the cost quotations on purchased parts
were solicited only from those vendors who supplied the same com-
ponents used in the prototype assemblies. Since most of these
suppliers were unable to quote on mass production quantities, the
lower quantity costs were extrapolated to estimate the cost of
10,000 and 1,000,000 units per year.
Table 16 presents the detailed cost figures for the Recycler
/Heater unit in quantities from 1 unit to 1,000,000 units per
year. The assumptions used in the cost analyses are that the
unit would be assembled and tested at the manufacturer's plant -
and shipped to a local distributor or contractor in three parts
(i.e., the processor tank assembly, holding tank, and hot water
storage tank). The distributor would handle the local installa-
tion. The estimated installed costs, which include a 33-1/31
G§A cost and a 501 profit and commission allowance, are shown to
vary from a high of $8812 per single unit production per year to
$5098 for'the production of 1,000,000 units per year.
Operating costs are based only on the cost of replacement
parts on the assumption that the compressor drive should be com-
pletely overhauled and the mechanical seals in the recycle and
68
-------
Table 16 PROJECTED COST OF RECYCLER/HEATER
Annual Production Rate
Cost Item
Vapor Compressor
Compressor Motor
Relief Valve
Recycle Pump § Motor
Condensate Pump
Pulleys § V-belt
Feed Valve
Jet Pump
Tank Heater
Level Controller
Vacuum Switch
Delta P Swtich
Pressure Switch
Sump Level Switch
Sump Piping
Condenser Coil
Spray Ring
Spray Nozzles
Tank Weldments
Tank Flanges
V-Band Clamp
Demister Material
Condensate Pump Motor
Insulation
Miscellaneous Plumbing
Electrical Suppliers
Assembly Labor § O'H'D.
Packing § Shipping
Total
G§A Expense (33-1/3%)
Total Manufacturing Cost
Profit § Discounts (50%)
Installation Cost
Installed Cost
Average Cost*
Annual Maintenance
Total Annual Cost
1
$ 279
118
32
160
52
20
76
47
40
112
17
65
4
8
14
105
50
10
1585
20
44
40
23
126
225
104
800
180
$4356
1452
$5808
2904
100
$8812
$~F99
100
$ 999
100
$ 228
90
26
135
33
16
47
42
28
70
16
57
4
8
13
87
40
7
1275
10
20
30
18
113
202
94
640
164
$3513
1171
$4684
2342
100
$8126
$~~8T9
100
$ 929
10,000
$ 200
80
21
115
24
13
33
40
22
50
15
53
3
7
12
78
35
5
1125
6
12
20
16
100
180
84
480
148
$2977
992
$3969
1984
100
$6053
$~6T7
100
$ 717
1,000,000
$ 150
70
17
100
20
11
26
39
19
40
14
51
3
6
11
74
33
4
1000
5
8
10
15
87
160
74
320
132
$2499
833
$3332
1666
100
$5098
$ 520
100
$ 620
* Ammortized over 20 years § 8%/year
69
-------
condensate pumps replaced every 30 months, and that the unit is
operated for 140 hours each week. It is assumed that this main-
tenance would be handled by the local dealer and that labor costs
would be covered by a five year renewable service guarantee issu-
ed by the manufacturer. It is further assumed that lubrication
would be conducted by the user every three months with the aid of
a lubrication kit supplied by the manufacturer. Lubrication of
the compressor drive would be accomplished from outside the unit,
but would require the user to open the circuit breaker at the
panel board and open a vacuum breaker located on the unit. In
addition, the user is required to clean the lint filter period-
ically - and, not more than once per year dump the concentrated
liquor to the sewer or perhaps to a catch basin for pick up by a
waste disposal service. Electrical power costs are not included
in the operating costs since these costs are essentially the same
as an equivalent capacity electrical water heater.
A useful life of 20 years and an 8% interest rate were as-
sumed to estimate the "actual" annual average cost - because this
type of unit must be designed to achieve a long useful life, and
the current prime rate is near 8%. Thus, with an annual mainten-
ance cost of $100, the total annual cost ranges from $999 to
$620. Since these could be lowered if the unit was redesigned,
they are considered to be the maximum cost of owning and operat-
ing a household size Recycler/Heater.
Water and Sewer Costs
Assuming that the water recovery appliance operates 20 hours
per day, 7 days per week the total volume of water recovered is
22.7 liters/hour X 140 hours/week, or 3180 liters/week, or an
average of 165,360 liters (584 cubic feet) per year. The costs
to the residential user for this amount of water in different
metropolitan areas across the country are shown in Table 17.
These costs include the commodity charge for metered water and an
equal sewer charge, and are based on a monthly billing rate.
They are an indication of the cost variations between areas
served by most municipal water utilities. The "outside city" or
suburban water and sewer costs are estimated to be double the
amounts determined for "within city" costs - because most subur-
ban waters must be "softened", or transported over longer dis-
tances. As an example of perhaps the highest cost of water in
the United States, residents in Alaska outside the city limits of
Fairbanks and Anchorage pay as high as $0.05 per gallon ($0.013
per liter).* Therefore, the cost of 165,360 liters per year to
these users would be over $2,100 per year; these residents, of
course, have learned to conserve water as much as possible.
H. J. Coutts, Personal Communication, Artie Environmental
Research Lab., EPA, College Alaska.
70
-------
Table 17 TYPICAL WATER AND SEWER COSTS
Location § Reference Within City Outside City
New Haven, Connecticut $ 73.48 $ 146.96
New Haven Water Company Rate Schedule
Oakland, California > 81.64 163.28
Dallas Water Utilities Survey, 1974
San Diego, California 83.06 166.12
Dallas Water Utilities Survey, 1974
Fort Worth, Texas 74.72 149.44
Dallas Water Utilities Survey, 1974
Indianapolis, Indiana 94.48 188.96
Dallas Water Utilities Survey, 1974
Nashville, Tennessee 89.12 178.24
Dallas Water Utilities Survey, 1974
Kansas City, Kansas 46.64 93.28
City of Kansas City Rate Schedule
Chicago, Illinois 33.12 66.24
Rate Schedules
-------
Potential Demand
Comparison of Tables 16 and 17 indicates that even if 1,000,
000 Recycler/Heaters were mass produced each year they would not
be economical to use in typical metropolitan areas. However, if
the unit was redesigned to reduce the total annual cost by a fac-
tor of 4 or more, the purchase of a Recycler/Heater could be jus-
tified by homeowners in most suburban areas. Consequently, it is
recommended that the development of a low-cost design be consid-
ered.
The developed Recycler/Heater, with a few minor improve-
ments, is currently economical to use in Alaska suburban homes -
even if it is produced at the rate of one unit per year. Thus,
it is recommended that one of these units be evaluated in a sub-
urban home in Alaska. Military installations where water and/
or sewage must be transported by vehicles can also justify the
use of the current design.
72
-------
SECTION IX
APPENDICES
Design Calculations
As stated in Section IV of this report, stepwise numerical
computations were performed in order to find the power require-
ments for the processor as a function of evaporator temperature,
TI. These calculations were carried out in one-degree increments
in the temperature range of 152°F to 160°F. All the numerical
results are presented in tables A-l, A-2, and A-3.
Table A-l shows the variations in the recycle flow rate re-
quirements, Gj' . It is seen that cj' must increase as TI in-
creases in order to maintain the flash evaporation process re-
covery rate, ci> , constant at 50.13 Ib/hr (6 gph) .
In Table A-2 the compressor shaft horsepower requirements,
Xi/Ja, , are given. As temperature TI increases the power de-
creases since both the volumetric flow, ir^cO , and the pressure
rise, Ajp, , decrease. The shaft speed, N, also decreases with
decreasing temperature due to decreasing specific volume, tr, ,
and slippage, S. It is noted that for these computations it was
convenient to express equation (4) in Section IV in the following
form.
r
l
__ P.O..
Table A-3, which gives the power requirements for the re-
cycle pump, is a solution of equation (8) in Section IV. The
determination of the condenser coil pressure drop, A-p1 , re-
quires the solution of the heat transfer relationships present-
ed in Figure 7 of Section IV in order to determine the coil
length, L. Then the total pressure drop is found by use of the
Darcy formula for smooth tubes - namely,
v'oz * L (A2>
where (A-p'),00 is the pressure drop per 100 feet of tubing. For
smooth tubes the friction factor, f. , is a function of the
73
-------
Table A-l RECYCLE FLOW REQUIREMENTS*
Tl
C°F)
152
153
154
155
156
157
158
159
160
Pl
(psi)
3.811
4.003
4.102
4. 203
4.306
4.411
4.519
4.629
4.741
(ftVlb)
92.68
90 . 57
88.52
86.52
84.58
82.69
80.84
79.04
77.29
hf
(Btu/lb)
119.89
120.89
121.89
122.89
123.89
124.89
125.89
126.89
127.89
(Btijlb)
1126.9
1127.3
1127.7
1128.1
1128.6
1129.0
1129.4
1129.8
1130.2
hrhf
(Btu/lb)
1007.01
1006.40
1005.81
1005.21
1004.71
1004.11
1003.51
1022.91
1002.31
hf-hf
hrhf
0.0119
0.0109
0.0099
0.0090
0.0080
0.0070
0.0060
0.0050
0.0040
ej'
(Ib/hr)
4213
4599
5064
5570
6266
7161
8355
10026
12533
* CO = 50.13 Ib/hr; T3 = 165°F; Te = 164°F; hf = 131.89 Btu/lb.
-------
Table A-2 COMPRESSOR POWER REQUIREMENTS*
en
TI
152
153
154
155
156
157
158
159
160
* D =
V, 6J/60 M S
(£t3/min (rpm) (rpm)
77.
75.
74.
72.
70.
69.
67.
66.
64.
0.033 f
4
7
0
3
7
1
5
0
6
t3
2345
2294
2242
2191
2142
2094
2030
2000
1958
/rev; K = 386;
1369
1228
1202
1136
1072
1005
934
859
779
tf
M+S
(rpm)
3714
3522
3444
3327
3214
3099
2964
2859
2737
= 1.32; P2
AP
(psi)
1.524
1.
1.
1.
1.
0.
0.
0.
0.
332
233
132
029
924
816
706
594
Power
(hp)
1.
1.
1.
0.
0.
0.
0.
0.
0.
= 5.335 psi; *l~*ii =
30
20
00
90
80
70
61
51
42
0.40
-------
Table A-3 PUMP POWER REQUIREMENTS*
TI Y! NRe / AP1QO AT «ln Hv HA U L AP' Power
(°F) (fps) xlO-3 xlO5 (psi) (OF) (Btu/hr-ft2-°F) (ft) (psi) (hp)
152 7.74 101.7 17.7 12.87 7.0 4.7 2678 2282 1206 45.3 5.8 0.057
153 8.43 110.8 17.5 15.10 6.5 4.4 2840 2450 1287 44.8 6.8 0.073
154 9.28 121.9 17.2 17.98 6.0 4.2 2884 2656 1348 45.1 8.1 0.096
155 10.31 135.5 17.0 21.94 5.5 3.9 2972 2889 1428 45.7 10.0 0.130
156 11.59 152.3 16.5 26.91 5.0 3.6 3066 3186 1520 46.1 12.0 0.180
157 13.23 173.8 16.0 33.99 4.5 3.4 3178 3558 1629 46.5 16.0 0.270
*•
158 15.43 202.8 15.5 44.80 4.0 3.1 3302 4041 1761 47.1 21.0 0.410
159 18.50 243,1 15.0 62.32 3.5 2.8 3440 4678 1912 47.9 30.0 0.700
160 23.12 303.8 14.3 92.80 3.0 2.5 3650 5625 2128 48.3 45.0 1.300
* D '= 0.0625 ft; D; = 0.0555 ft; V* = 0.016 ft3/lb; 7J1 = 0.5; k/t = 55866
01 Btu/hr-£t2-0p
-------
Reynolds Number, NRG, only, and can be obtained from the Moody
Diagram for a Reynolds Number defined by the flow velocity, V,
and inside tube diameter, "D^ .
Design Details
The detail design of the Wash Water Recycler and Heater is
described by the following list of assembly and detail drawings,
and parts lists. (On file with EPA and Life Systems, Inc., Cleveland,
OH.)
14958-3108-E-100 Recycler/Heater Assembly
-E-114 Processor Assembly
-E-113 Weldment
-E-112 Storage Tank
-R-106 Evaporator Tank
-R-100 Condenser Tank
-D-109 Flanged Head
-R-101 Condenser Cover Plate
-D-102 Cover Plate Channel
-B-103 Support Brackets
-B-104 Channel Gasket
-B-105 Cover Plate Gasket
-B-107 Flange Gasket
-R-108 Condenser Tubing Assembly
-C-110 Tubing Support Brackets
-D-lll Spray Manifold Assembly
-E-115 Insulation Assembly
-C-117 Control Schematic
-C-200 Relief Valve Assembly
PL-100 Parts List, Recycler/Heater Assembly
PL-114 Parts List, Processor Assembly
PL-200 Parts List, Relief Valve
Evaporator Tank
The evaporator tank weldment design is shown in drawing
#3108-R-106. The shell is constructed of 10 gauge (.1345 inches)
low-carbon, hot-rolled steel sheet, and has an ASME Code* allow-
able external working pressure of 11 psi.
In the evaporator the liquor from the condenser coil is
transferred to the spray manifold assembly. The flow exits the
coil through a 3/4-inch pipe coupling welded to the top of the
condenser cover plate. Then it splits into two paths via 1/2-
inch pipe sections, 180° apart, which connect to the spray mani-
fold concentrically within the annulus formed by the condenser
ASME Boiler and Pressure Vessel Code, Section VIII, Division
1 (see Figure USC-28.1 for a cylinder length to outside
diameter ratio of 1.98, and a outside diameter to thickness
ratio of 180.), 1974.
77
-------
and evaporator shells. In the spray manifold the flow from
each pipe feeds three equally spaced spray nozzels which have
an orifice diameter of 0.209 inches (0.53 cm). The jets are
directed downward approximately 75 degrees from the vertical,
and the spray angle is approximately 105 degrees. Thus a full
curtain is formed across the evaporator above the liquid level.
The evaporator shell contains nine weld-on pipe couplings
which are identified by numbered bubbles in the weldment draw-
ing #3108-R-106. The functions of these couplings are listed
as follows:
Coupling No.
1
2
3
4
5
6
7
8
9
Condenser Tank
Size
Function
1/4-18 NPT
1/2-14 NPT
1-11% NPT
2%-8 NPT
1/2-14 NPT
2-11% NPT
Connection for installing thermo-
couple wires, if desired.
Vacuum switch mounting
Vacuum gauge connection for
evaporator pressure reading.
Connection for purging non-con-
densible gases from condenser shell.
Connection for 115 VAC power lines
to compressor motor.
Connection for recycle liquor into
condenser coil.
Liquid level switch mounting
Connection for feed line
Connection for suction line to
recycle pump.
The condenser tank weldment design is shown in drawing
#3108-R-100. The tank consists of the condenser shell in which
the condenser coil is mounted, and a standard schedule 40, 4-
inch pipe section which is welded to the bottom of the shell.
The condenser shell is secured concentrically within the evapora-
tor shell via a weldment of the pipe support column to the bottom
head of the evaporator tank. This weldment insures complete
isolation of the condenser and evaporator sections. The pipe
section also serves to transfer the condensate or product water
out of the processor.
The condenser shell is constructed of 10-gauge, low-carbon
steel. The shell is closed at the top by a I/4-inch thick steel
plate which bolts to a rolled-steel, inside-ring flange welded to
the shell. Design calculations used to confirm the condenser
shell thickness, cover plate thickness, and flange dimensions
were based on a maximum internal pressure of 2 psi which is con-
trolled by a pressure relief valve in the cover plate. Since the
design working pressure is 0.92 psi, the relief valve is pri-
marily required to prevent overloading of the compressor motor
during transient or start-up conditions.
78
-------
The compressor drive assembly is mounted directly to the
condenser cover plate. The outlet of the compressor is sealed
from the evaporator by a rubber sleeve which is compressed into
a tappered hole in the cover plate. This sleeve arrangement also
serves as a flexible joint to relieve compressor housing stresses,
Vapor is transferred from the compressor outlet to the bottom
of the condenser shell via the cover plate channel and the con-
denser coil support pipe.
Condenser Coil
The condenser coil design is shown in drawing #3108-R-108.
The assembly consists of a central 2-inch brass pipe to which
two tiers of 3/4-inch diameter, spiral-wound copper coils are
horizontally fastened via three copper support brackets. The
brackets are brazed to the coils and serve as radial and axial
spacers. This method of assembly provides a rigid support while
minimizing thermally induced stresses in the tubing.
Inlet and outlet connections to the heat exchanger are made
with steel CPV (Combination Pump Valve Company) fittings which
are brazed to the open ends of the coils.
Storage Tank
The storage tank weldment design is shown in drawing #3108-
E-112. The shell is constructed of 10-gauge, low-carbon, hot-
rolled steel sheet and has a design internal working pressure of
76 psi, which is allowable according to the ASME Code formula
governing the head design. For a torispherical head, the max-
imum allowable working pressure is given by
P = SEt (Bl)
0.885L + O.lt
where: P = design pressure, psi
S = maximum allowable stress, 12000 psi
E = joint efficiency, 1
t = wall thickness, .1345 inches
L = crown radius, 24 inches
No corrosion allowance was used in this calculation.
The storage tank shell contains weld-on fittings which are
identified by numbered bubbles in the weldment drawing #3108-E-
112. The functions of these couplings are listed as follows:
79
-------
Coupling No. Size Function
1 %-14 NPT Condensate inlet
2 " Product water outlet
3 1-11% NPT Connection for heater/thermostat
4 %-18 NPT Connection for pressure switch
5 %-14 NPT Vent connection
6 %-18 NPT Temperature gauge connections
7 %-14 NPT Pressure/temperature relief
valve connection, or vent
connection
Weldment Assembly
The evaporator and storage tanks are welded into an integral
assembly according to the design shown in drawing #3108-E-113.
The tank center lines are three feet apart; this space forms
the sump tank which is open at the top. Standard light-steel
channels welded vertically at the front and rear of each tank
form the support legs for the assembly and a frame for securing
the insulation jacket. Additional channels at the bottom of
the structure form a rectangular frame to support the recycle
pump and product water pump assemblies. The total structure
weight is approximately 600 pounds (272 kg).
Insulation
The design of the insulation assembly is shown in drawing
#3108-E-115. Insulation is accomplished by twelve 24x48x2 inch
insulation panels which cover the sides and removable door of
the Recycler/Heater unit. Two additional panels are required to
cover the top of the unit. These glass fiber materials (Johns-
Manville Type 814) have a thermal conductivity of .020 Btu per
hr,, per ft^, per °F at a mean temperature of 110°F. The side
and rear insulation panels are cemented to thin (.060 inch) white
fiber glass-reinforced plastic sheets which are riveted to the
Recycler/Heater structure to form a smooth jacket all-around the
unit. The front panels are also cemented to a thin fiber glass
sheet. This sheet in turn is cemented to a separate rectangular
fiber glass channel frame which forms a quick access full length
removable door at the front of the unit.
Analytical Methods
All the analytical methods pertaining to the water quality
tests described in Section VI of this report are listed as follows:
CHEMTRIC Analyses
A. Total Residue: As per Standard Methods for the
Examination of Water and Wastewater, 12th edition
(1965), AWWA-APHA-WPCF, pages 534-535.
80
-------
B. COD; As per "Standard Methods", 13th edition (1971),
pages 495-499.
C. pjl: As per "Standard Methods", 13th edition (1971),
pages 276-280.
D. Specific Resistance: As per "Standard Methods" 13th
edition (1971), pages 323-327. Also YSI Model 31
Conductivity Bridge Instruction Manual.
E. Turbidity: As per "Standard Methods", 13th edition
(1971), pages 350-353. Also Hach Laboratory Turbidity
Meter Model 2100A Instruction Manual #1000-1-4-72-2 ed.
F< Sterility: The plastic bottle shown on the next page
is sterilized with the screw cap loosley in place
by autoclaving for 15 minutes at 250°F. The bottle
is stored at 2OC-8°C until used. The remaining sampl-
ing apparatus is assembled, sealed in a paper bag
and sterilized as above. In addition a paper cover
is placed over the needle prior to sterilization.
Sampling is accomplished by quickly removing the cork
assembly from the paper bag and inserting the cork
in the sample bottle. The needle is inserted into the
appropriate septum of the Recycler/Heater. Just prior
to needle insertion the septum is swabbed with iodine
saturated cotton to insure sterility.
Fluid Thioglycolate Medium (Scientific Products, Cat.
No. 21195) is used to determine sample sterility.
One ml of sample is aseptically pipetted into a test
tube of thioglycolate medium; the tube is incubated
at 35°C for 48 hrs. Standard sterility techniques
are used. Three tubes are innoculated for each sample
evaluated.
The results are recorded as positive or negative on the
basis of growth observed in the test tubes. If growth
is observed in all three tubes the result is recorded
as positive. If less than three tubes show growth the
results are recorded as negative.
81
-------
EQUIPMENT:
a. Rubber tubing
b. Bacteriological filter
c. Rubber stopper
d. Needle, hollow
e. Bottle, 500ml polypropylene
f. Cotton swabs
g. Laboratory incubator
h. Fluid Thioglycolate
i. Iodine solution
j. Laboratory autoclave
k. Pipettes, one ml
Subcontracted Analyses
The tests subcontracted to the Nalco Chemical Company,
Analytical Services Division, were performed as follows.
A. Metals: (Barium, Cadmium, Chromium, Copper, Iron,
Lead, Magnesium, Silver, Selenium): as per Methods
for Chemical Analysis of Water and Wastes, 1971, EPA
Manual, pages 78-155.
B. Ammonia: As per EPA Manual, pages 175-181.
c- Nitrate: As per EPA Manual, pages 201-214.
D. Cyanide: As per EPA Manual, pages 40-49.
E. Arsenic: As per EPA Manual, pages 9-10.
82
-------
F- Phenols; As per EPA Manual, pages 241-248.
G. MBAS: As per EPA Manual, pages 157-158.
H> Floride: As per Federal Register, Vol, 39, Part 2,
No. 206, pages 37, 730 to 37, 741.
I. TOG: As per gas chromatography using Beckman TOG
Analyzer.
J. Chloride: As per "Standard Methods", 13th edition
(1971), page 96.
K* Sulfate; As per "Standard Methods", 13th edition
(1971), pages 334-336. Also, ASTM Standard (1973)
Part 23, Water: Atmospheric Analysis, page 425.
Installation, Operation § Maintenance
The following instructions apply to the Recycler/Heater Units
shipped to (1) U.S. Army Medical Bioengineering Laboratory of
Fort Detrick, and (2) the Naval Ships R§D Center at Annapolis.
Installation
The schematic presented on the next page illustrates the
arrangement of components on the Recycler/Heater, and the re-
quired connections. In addition the schematic shows the gauges
and the replacement pumps which are recommended for laboratory
testing. The schematic arrangement of the electrical controls
is presented in figure A-l.
Preliminary
A. Remove the cabinet door on Recycler/Heater and inspect
all components for damage and loose electrical connections.
Call Chemtric if any damage or loose connections are found.
B. Remove the flanged head on the processor tank and inspect
the compressor drive for damage and loose connections or
fasteners. The flanged head is removed by removing the top
insulation panel and the upper section of the side insula-
tion panel. This section has four rivets at the front and
back side which must be drilled out with a 3/16-inch drill.
Replacement of the panel requires eight new rivets. Replace
the flanged head with a new gasket coated on both sides with
silicone vacuum grease.
C. Install clear flexible tygon tubing level gauges on sump
and storage tanks as shown in the installation schematic.
These tubes can be taped to the outside of the insulation
jacket.
83
-------
oo
Lr tt
QP_
W*3
Figure A-l INSTALLATION SCHEMATIC
-------
D. Remove the 20-mesh screen in the Y-strainer and clean
if necessary. Close the strainer valve.
E. Close the concentrate sample valve.
F. Install the peristaltic pump. Note that this is a
double-head single-motor pump. Connect the tubing to
the heads as shown in Figure A-l, and electrically in
Figure A-2. The peristaltic pump is located outside the
insulation jacket close to the unit.
G. Connect a portable vacuum pump into the purge line at
point shown in Figure A-l. Note that the vacuum pump
is only used for initial evacuation of the processor
tank, and should be electrically connected to a sep-
arate power source.
H. Install wall mounted fusible (30 ampere slow-blow fuse)
circuit breaker with manual control; install push
button switch 1PB in close vicinity to the unit. Make
interconnection wiring as per figure A-2. The main
power line from the circuit breaker is connected directly
to the terminal strip located in the wiring box mounted
on the processor tank; terminals 11 § 12 on unit at Fort
Detrick, terminals 7 § 8 at Annapolis. Wiring to push
button switch 1PB can come directly from the wiring box
terminal strip. Check that jumper wires are in place in
pressure switch IPS. Place circuit breaker and push
button switch in "off" position.
Filling § Heating
A. Fill the storage tank with tap water to the outlet line
level noted in Figure A-l; mark this position on the
liquid level gauge.
B. Fill the sump tank with tap water to the overflow line
level noted in Figure A-l; mark this position on the
liquid level gauge.
C. Close the circuit breaker. The storage tank heater
will then come "on", and feed valve will "open".
D. Start the vacuum pump and begin to evacuate the processor
tank; as the processor vacuum increases the feed rate
increases due to the higher AP. Evacuate to 26 inches
HG vacuum, and turn-off vacuum pump and close vacuum valve,
E. The processor is filled when the feed valve snaps closed.
During filling observe the sight gauge on sump tank to
insure that water level does not go below feed line
level; mark this position on liquid level gauge. Since
the processor tank holds 33 gallons and the feed sump
85
-------
//5\SAC
0 ^-^ 0
00
ON
ITS
r^
IFS
"ZJ
L€\i£L 5V^
-*r\ •-
i IP& ! IPs
^^
PUSH SUTTW (•—i
^
$
^
V)
V
Figure A-2 CONTROL SCHEMATIC
-------
holds 29 gallons, additional filling is required.
F. With the push button switch in the "off" position,
remove cover on vacuum switch 2PS and remove compressor
motor wire located at far right terminal facing switch.
G. Check operation of the recycle, and purge and condensate
pumps by placing push button switch 1PB in "start" position;
recycle pump, purge pump, and condensate pump should come
"on". Note that the feed valve will open to allow addition-
al fluid into the processor to fill the recycle line. The
recycle pump pressure should be approximately 34 psig when
the processor is at atmospheric pressure, and approximately
20 psig when the processor is at 26 inches HG. Allow re-
cycle pump to run for several hours to deaerate the fresh
feed stock. (Note: Check peristaltic pumps for proper
pumping direction).
H. Depress push button switch 1PB to "off" position. Replace
compressor motor wire in vacuum switch 2PS.
I. Close the insulated door and allow 16 hours for heat-up.
Start-Up
A. Check the vacuum gauge; vacuum should be approximately
23 inches HG after heat-up period.
B. Check the storage tank temperature; temperature should
be 16QOF.
C. Open the strainer valve.
D. Actuate push button switch 1PB; recycle pump, compressor,
purge pump and condensate pump should come "on".
E. The processor is now operational; unit will automatically
process water in feed sump, and store the processed water
in storage tank.
"'^,
F. The processor should be turned off or feed sump refilled
when the liquid level in the sump is approximately three
inches above the feed line level; mark this position on
the liquid level gauge.
G. When the processor is turned "off" the heater remains on,
unless the circuit breaker is opened, to maintain the
stored water at pasteurization temperature.
Operation
Once the unit is initially evacuated via the use of a
vacuum pump inserted into the purge line at the position shown
87
-------
in Figure A-l, the day-to-day operation is simply controlled by
the push button switch 1PB. Before starting the unit each day it
is important to observe the vacuum gauge and temperature gauge
to insure that the heater in the storage tank is operative, and
that the processor tank is at saturation pressure. The typical
operational procedure is as follows.
A. Check the storage tank temperature; it should be in the
range of 157 to 163°F.
B. Check the vacuum in processor tank; it should be 23 to
25 inches HG.
C. Fill the sump tank with wastewater to line marked on
liquid level gauge - just below overflow line.
D. Depress push button switch 1PB to "start" position -
to start the recycle pump, compressor, purge pump, and
condensate pump.
E. Check the tubing in the peristaltic pumps. For maximum
life of tubing, pull through a new section of tubing
(while pump is running) every 10 hours of operation.
When tubing takes a permanent set replace with new line.
To replace tubing shut-off purge line valve and conden-
sate line valve.
F. Maintain the sump tank level above "low" mark on level
gauge - i.e., just above the feed line.
G. Maintain the storage tank level above "low" mark on level
gauge - just above outlet line. This will insure that
the storage tank heater is always immersed in liquid.
H. Remove recovered water from storage tank as necessary
via the outlet line valve. Note that a vent hole is
provided to prevent pressure build-up in the storage tank.
I. Check the compressor discharge temperature via the type
"T" thermocouple provided. When this temperature exceeds
approximately 200°F remove front door panel to stabilize
the temperature. Replace the door when unit is shut-off.
J. Turn unit "off" as necessary by depressing push button
switch 1PB to "stop" position.
K. Note that between runs the processor temperature will
naturally decrease. Typically, for a 16 hour shut-down
between runs the processor will cool approximately 20F
degrees. This cooling will cause the absolute pressure
to drop so that the next run always begins at a higher
vacuum.
88
-------
Maintenance
The Recycler/Heater Units require the following periodic
maintenance.
A. Replace the peristaltic pump tubing when it takes a
permanent set - that is, it remains in a flattened
position. Fifty feet of tubing, Cole-Parmer #6411-45
(0.1925 I.D. x 0.3920 O.D.) should last 750 operating
hours - provided it is repositioned in the pump every
10 hours of operation.
B. Lubrication of the compressor drive should be checked
every 500 hours of operation. Lubrication consists of:*
(1) Compressor timing gears - use Chevron OC Turbine
Oil #36.
(2) Compressor bearings at drive end - use Chevron
polyurea EP grease #2.
(3) Compressor motor bearings(2) - use Chevron SRI
grease #2.
C. Remove condensate line strainer (20 mesh stainless steel
screen) every 100 hours of operation and clean and
blow-out with compressed air. Replace Strainer using
Loctite sealant/teflon (PS/T) on the strainer pipe
fitting.
D. Remove lint strainer and clean periodically as required.
A maintenance manual and list of spare parts prepared by the
manufacturer on the compressor, recycle pump, and condensate and
purge pumps, are provided with each unit. Any repair work re-
quired on the compressor should be handled through Chemtric. The
only replacement item in the recycle pump is the shaft seal. The
seal number is P-2752; it can be obtained through Chemtric, or
any Worthington Pump Distributor. A list of these distributors
is furnished with each unit. Replacement parts for the peristal-
tic pumps are the sealed bearings in each head, which can be ob-
tained directly from the Cole-Parmer Company. For replacement
of bearings and seals in the compressor motor and recycle pump
motor, these items can be ordered directly from the motor manu-
facturer according to the nameplate information on each motor.
All the control components - i.e., the storage tank tempera-
ture switch and heater (ITS), liquid level switch (IPS), evapor-
ator vacuum switch (2PS), and solenoid feed valve (ISOL) -
See Bulletin RME-12 Sutorbilt, or Bulletin 37-3-602 Gardner-
Denver Company, for complete compressor maintenance details.
89
-------
should last the life of the unit. However, should any of these
items need replacement or service contact the manufacturer
according to the information presented below.
The heat exchanger and relief valve are items that should
last the life of the unit. Should these items become defective
such that a cleaning operation cannot correct, replacements can
be obtained from Chemtric according to the part numbers #3108-
C-200 Relief Valve, and #3108-R-108 Condenser Tubing Assembly.
Replacement Parts
Replaceable parts should be ordered from the respective
manufacturers, using the information listed below.
Compressor Drive Assembly
A. Compressor: Sutorbilt Model 4L, Fuller Company, Compton,
California - or the Gardner-Denver Company Model 2PDR,
Quincy, Illinois.
B« Motor: (Gould Incorporated, Century Electric Division,
St. Louis, Missouri) 3/4 HP, 3450 rpm, NEMA 56 frame,
single phase, 60 HZ, 115 volt, ball bearing, TENV, con-
tinuous duty, rigid base for belt drive, type CP capacitor
start CW rotation. Motor to have the following special
features:
1. Class H insulation.
2. Capacitor and relay mounted outside of high
ambient environment.
3. No conduit box - lead wires exit through rear
end-bell (1/2-NPT Hole). Lead wire length -
10 inches.
4. Name plate not to be fastened to frame.
C. Belt: #AX31, Dayco Gold Label cog belt.
D. Drive Sheave: Bushing #1215, 5/8-bore; 3.4 PD
pulley, Dodge dual-duty, taper-lock sheave.
E. Driven Sheave: Bushing #1615, 5/8-bore; 3.8 PD
pulley, Dodge Dual-duty, taper-lock sheave.
F. Connector § Receptacle (motor power lines): #2004-505
receptacle, #£2004-512 connector, Cam-Lok Division,
Empire Products Company, Cincinnati, Ohio.
G. Flange Gasket: #3108-B-107, Chemtric, Inc.
90
-------
Recycle Pump Assembly
A. Pump: Model D-520, 1-1/4 x 1 x 4, cast-iron construction,
Noryl impeller, diameter 4 inches, John Crane Type 21
Mechanical Seal (Ni-Resist vs. carbon, Viton bellows),
Worthington Pump International, Division of Worthington
Corporation.
B. Motor: 1/3. 1/2. or 3/4 HP, 3450 rprii, NEMA 56J face
frame; stainless steel threaded shaft, 5/8 dia,'single
phase 60 HZ, 115 vole, ball bearing, OOP or TEFC, contin-
uous duty, CCW rotation. Order from Worthington Pump
Division, or direct from a manufacturer of electric motors.
Note: Original motor has special Class F Insulation
(thermal protective switch removed). Replace-
ment motors with standard insulation must have
thermal protection and require water cooling
via a 1/4 O.D. copper coil wrapped around
motor frame.
Condensate and Purge Pumps
A. Pump Head XPurge): Masterflex tubing pump, Cole-Parmer
#7015 standard-head steel-rotor assembly.
B. Pump Head ^Condensate): Masterflex tubing pump, Cole-
Parmer #7015-20 add-on head steel-rotor assembly.
C. Motor Drive: Masterflex fixed speed drive, 575 rpm,
Cole-Parmer #7539, Fixed Speed MF Drive, 115 VAC, 60 HZ.
D. Tubing: Silicone tubing, 0.1925 "I.D. x 0.3920" O.D.,
Cole-Parmer #6411-45.
Control Components
A. Storage Tank Heater/Thermostat (H/ITS): ARTM-2000, 2000
watts^ 120volts immersion heater with built-in thermo-
stat, Chromalox.
B. Evaporator Vacuum Switch C2PS): Class 9016, Type GVG-1,
Form R, Square-D-Company.
C. Evaporator Liquid Level Switch (IRS): Model TF-63, Type
S-l switch (SPST), NEMA 1 enclosure, 2-1/2-inch stainless
steel float, 6-inch stem length, set for minimum differen-
tial, Magnetrol Int'l, Downers Grove, 111.
D. Feed Valve (ISOL): Model PV-514-B2 Pinch yalve, 115 VAC,
6D HZ, Trombetta Corp., Milwaukee, Wisconsin.
E. Push Button Switch (1PB): Class 2510, Type MCG-1, 2-pole,
NEMA size M-l, B-36 thermal element, Square-D-Company.
91
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-76-289
3. RECIPIENT'S ACCESSIOWNO.
4. TITLE AND SUBTITLE
DEVELOPMENT AND TESTING OF A WASTEWATER
RECYCLER AND HEATER
5. REPORT DATE
December 1976 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Victor J. Guarino
Robert A. Bambenek
8. PERFORMING ORGANIZATION REPORT NO.
Project 3108
9. PERFORMING ORGANIZATION NAME AND ADDRESS
CHEMTRIC Incorporated
5301 Wesley Terrace
Rosemont, Illinois 60018
10. PROGRAM ELEMENT NO.
1BC611
11. CONTRACT/GRANT NO.
68-03-0436
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory--Gin.,OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
Jointly funded by the EPA, NASA, Army, HUD and Coast Guard
16. ABSTRACT
This report describes the design, fabrication and testing of a dis-
tillation unit that utilizes the flash evaporation and vapor compress-
ion processes to recover usable hot water from contaminated wastewater.
This unit does not require the use of any expendable materials, and it
is capable of recoverying more than 96% of the available wastewater
while using less than 80 watt-hours of energy per liter of recovered
water.
Two units were fabricated - one for the U. S. Army Medical R § D
Command, and one for the National Aeronautics and Space Administration.
The Army unit was tested for 38 days with real laundry water, and 21
days with a synthetic brine water that simulates concentrated waste-
water from a hospital. The results achieved with real laundry water
were as expected - i.e., neutral water with very low solids and low
turbidity; however, the presence of organic volatiles and ammonia in
the synthetic brine water caused the water recovered during the second
test to be unacceptable - thus indicating that pretreatment and/or ad-
ditional processing is necessary when these contaminants are present.
An economic assessment is also included in the report.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Distillation
Flashing--Evaporation
Waste Water
Water Heaters
Reclamation
Wastewater Concentra-
tion
Water Recovery
Vapor Compression
Recycler/Heater Com-
pression Distillatibn
13B
8. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
104
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
92
U.S. GOVERNMENT PRINTING OFFICE: 1977-757-056/5585 Region No. 5-11
------- |