United States
Environmental Protection
Agency
Municipal Environmental Researc
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-82-043 August 1982
Project Summary
Water Reclamation and
Automated Water Quality
Monitoring
E. L Jeffers, R. L. Brooks, D. Nibley, J. D. Poel, J. Perreira, R. H. Nuss, K.
Nishioka, W. J. Sanchez, Jr., and D. F. Kriege
The Santa Clara Valley Water District
owns and operates a water reclama-
tion facility located in the Palo Alto
Baylands area in Northern California.
The purpose of the facility is to provide
reclaimed water suitable for injection
into the groundwater, thereby provid-
ing a salt water intrusion barrier and,
secondarily, to provide a research
facility for various ongoing projects.
The project results summarized here
involved using"the NASA/Ames
Research Center's Water Monitor
System to collect data on the water
reclamation process train. The Water
Monitor System is a continuous online
water quality monitoring system that
automatically measures 14 water
quality parameters in addition to 9
trace halocarbons. The system was
built and operated by Boeing Aero-
space Company personnel through a
NASA contract. For a period of 3-1 /2
years, the system has gathered infor-
mation on water quality changes at
intermittent points throughout the
treatment process train. This report
presents the results of the last 8-
month period, including performance
and costs of operation for both the
Water Reclamation Facility and the
Water Monitor System. These results,
especially for the water treatment
processes, may be unique to this
facility and should be interpreted
cautiously.
This Project Summary was devel-
oped by EPA's Municipal Environ-
mental Research Laboratory. Cincin-
nati, OH, to announce key findings of
the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
The Santa Clara Valley Water District,
in cooperation with the cities of Palo
Alto, Los Altos, and Mountain View,
embarked upon a developmental pro-
gram of water reclamation and injection
of the reclaimed water into underground
aquifers in the South San Francisco
bayfront area. The purposes of this
program were to demonstrate the
technical and economic feasibility of
certain reclamation processes and to
attempt to provide a freshwater barrier
to the intrusion of saltwater into a
shallow aquifer. The wastewater supply
to this reclamation facility is the effluent
from the Palo Alto Regional Water
Quality Control Plant.
The Water Reclamation Plant provides
tertiary treatment to the secondary
effluent from the Palo Alto city plant. In
addition to its basic function of providing
a supply for groundwater recharge, the
reclamation plant can produce water of
lesser quality for use in golf course
irrigation or as an in-plant supplemental
supply for the Palo Alto city plant's
Reclaimed Water System. A schematic
of the plant is shown in Figure 1.
As an outgrowth of its involvement in
water reclamation and water quality
monitoring for both spacecraft and
domestic applications, NASA's goal was
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Lime
Secondary
treated
Influent H~\
el
(Polymers) C02
\ I kLtfcLi 1 n n
1 J_ ^**^^J_ i _"\ i i
Flash Flocculation/ A eration
mix clarification (Aeration pumps v*
not operated duri
I this test period)
Pec
'ere
ng
*l
C/2
^•^•M
rr
[Oc
arbonation
D
Filtration
Current
sample point
Ozonation
Activated
carbon
Filtration
[g[ Effluent
Storage
Notes:
1. Maximum of six sample points active at one time.
2. Parenthesis indicat chemical feed capability not
currently utilized.
Figure 1. Santa Clara Valley Water District reclamation facility at Palo Alto.
to develop, test, and transfer the
automated WMS (water monitor system)
technology to civil applications The
objective of this project was to develop a
system whereby water quality monitor-
ing could be performed as it would be
done in a spacecraft, on-line and in real-
time. The design goal was to establish
the capability to determine conformance
to future high quality effluent standards '
and, thereby increase the viability for
reclamation and reuse of wastewater.
The WMS includes both commerically
available and NASA-developed sensors,
an automated sample collection and
distribution system, and a computerized
data acquisition and reporting system.
Figure 2 is a schematic of the system.
The assembly and checkout of the WMS
portion of the project was completed
under separate contract. The field
demonstration test phase started in July
1977 and ended on February 28, 1981.
The final portion of the test period was
from July 1980 through February 1981.
This portion of the test period was jointly
funded by NASA, the EPA, the California
State Department of Water Resources,
and the Santa Clara Valley Water
District.
Test Program Objectives
This Project Summary highlights the
results for the test period July 1980
through February 1981. Operational
and performance data for the WMS, as
well as subsystem downtime and O&M
(operations and maintenance) costs,
were recorded. Similar data were
recorded by the Santa Clara Valley
Water District for the reclamation plant
Additional test data were recorded on
the water quality at various points
within the reclamation plant as mea-
sured by the WMS sensors and through
grab samples by the city of Palo Alto
Laboratory. These data were used to
evaluate the performance, reliability,
availability, and costs of the reclamation
plant, its individual processes, and the
WMS and its components. Major
problems encountered in the operation
of the WMS and the reclamation plant
are discussed. Note that the problems
and costs reported here may vary
considerably from those of a nonexperi-
mental plant or monitoring system.
The objectives of the test program
described in this report were as follows'
1. To determine the steady-state
performance (ability to remove
contaminants) of each unit process
in the water reclamation facility
based on WMS data.
2. To determine WMS, plant, anc
unit process availability. Availa-
bility is defined as the portion ol
time that an item operates or
demand. Availability was mea-
sured as follows:
A = 10OT/(T + D)
where, A = availability, %
T = operating time, hours
D = Downtime for repair
hours
T+ D = total available oper
ating time, hours
Once established, availability can be
used to estimate annual repair time
Thus, for a continuously operated item
D =(1-A/100) (365 days/year
(24 hours/day)
3. To determine WMS and reclame
tion plant reliability. Reliability u
defined as the percentage of th<
operating time that an item per
forms within specified limits. Fo
the water reclamation plant
reliability was measured as thi
percentage of time that a wate
quality parameter was withit
specified effluent limits. The WMJ
data were statistically evaluate!
based on a log-normal data distri
bution model and compared wit!
an MCL (maximum concentratioi
limit) The MCL's for the plant an
shown in Table 1 The percentagi
of time that a measured paramete
was less than the MCL repre
sented plant reliability for tha
parameter. The product whei
availability is multiplied by relia
bility gives the portion of the tota
available operating time that ai
item will perform within givei
limits
P = (A) (R)
where, P = performance achievei
4 To determine WMS and reclama
tion plant operating and mam
tenance costs.
Process Performance
Results
1. The following conclusions relativ>
to process performance were base'
on the WMS data:
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Consumables
• Tap water
• Compressed air
• Analytical gases
• Oxygen
• Nitrogen
• Hydrogen
• Ammonia
• Carbon monoxide
• Electrical power
• Chemical reagents
Plant
influent
WMS Trailer
Unfiltered
Plant
effluent
Six
multipoint
samples
o
<>
Filt
'
ered
K
>
V
•
• J
• L
•/
• >
• 1
• (.
• ]
• i
• /
c
./
• i
• (
d
• (
c
1
roc
• Turbidity
pH
Ammonia
Nitrate
Conductivity
Temperature
Sodium
Residual
chlorine
Hardness
Biosensor
Coliform
detector
Gas
chromatograph
Commands
Status
~I
Computer
L
Figure 2. Water monitor system configuration
a. Chemical clarification removed
over 90% of the influent sus-
pended solids (biomass) and as
much as 30% of the organic
contaminants [TOC (total organic
carbon)]
b. Flocculation (floe) carryover from
the chemical clarification process
results in additional loading on
the mixed-media filters. This
caused decreased filter run times;
i.e., more frequent backwashing.
c. Except for some reduction in trace
halocarbons and biomass, the
contribution of ozone to water
quality did not appear to be
significant at the concentrations
used in the study
d A reduced level or many dissolved
contaminants was characteristic
of water processed by activated
carbon, when its useful life was
not exceeded. The chemical
oxygen demand effluent limit of
10 mg/L, however, was difficult
to achieve without significant
cost incurred by continuously
regenerating carbon.
2. The capability to collect and process
data for convenient and improved
analysis of water quality informa-
tion was demonstrated Over three
million water quality measure-
ments were recorded during the
test period and are summarized in
the full report
3. Automated water quality monitor-
ing will be an economic necessity in
the future as effluent quality control
restrictions are tightened. The costs
of repetitive laboratory analyses
will become prohibitive, thereby
increasing the demand for auto-
mated sensing, analysis, and re-
porting.
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4. There is a need for improved
reliability of many of the available
components used for automated
water quality monitoring.
Recommendations
1 When using lime for chemical
clarification, it is recommended that
a filtration step be included before
GAC (granular activated carbon)
sorption. This will reduce the
possibility of clogging the GAC with
coagulant and/or calcium carbon-
ate precipitant.
2. The potential for reducing activated
carbon regeneration costs by oper-
ating the towers in a "biologic
activated carbon" mode (no re-
generation) should be explored.
3. The WMS as configured is not ideal.
The mobility design criteria dictated
its design The following factors
should be considered in designing
an in-place integrated plant water
quality monitoring system:
a. Locate electronic equipment in an
area away from potential contact
with process or other chemical
exposure.
b. Use state-of-the-art computer
technology to simplify the data
acquisition system. Improvements
to equipment are constantly
being made
c. The system should be designed
for automatic fault detection. If
not, the time required to diagnose
electronics failures will far exceed
the time required to correct the
problem.
Water Monitoring System
(WMS)
O&M Costs
As part of the project's objective of
evaluating performance, the O&M costs
for each of the sensors and subsystems
were determined. The actual expenses
incurred during the test period were
scaled to obtain a year's cost. The cost
covers all consumables, hardware, and
labor required for 12 months of contin-
uous operation. These costs reflect the
age of the hardware. The annual O&M
costs for the WMS sensors and sub-
systems were $94,125.
The distribution of costs may be
summarized as follows:
Labor Materials Total
Operations 18.0% 4.9% 22.9%
Maintenance 57.6% 19.5% 77.1%
Total 75.6% 24.4% 1OO.O%
An additional goal of the program was
to determine, when possible, the life
expectancy of the various systems.
These data are in the full report.
Availability and Reliability
WMS availability (percent of time the
subsystem and sensors operated on
demand) was monitored during the test
period. The downtime recorded for each
of the sensors and subsystems included
actual repair times and downtime at-
tributed to waiting for necessary
reagents or parts.
Sensor and subsystem reliability
(percent of operating time the data
generated were valid) values were
calculated based on the number of
Table 1. Reliability of Palo Alto Reclamation Facility
Parameter
Chemical Oxygen Demand
Trihalomethanes
Total Nitrogen
pH
Dissolved Oxygen
Hardness
Sodium
Total Residual Chlorine
Conductivity
Turbidity
Maximum
Concentration
Limit
lOmg/L
JOOmg/L
5mg/L
8.5
500mg/L
250mg/L
1600/imho/cm
5NTU
Minimum
Concentration
Limn
65
1 mg/L
1 mg/L
Reliab
Period A
65.0% '
>99 9%
86 1% 2
INH3)
187%
>999%
786%
>999%
762%
>99.9%
ility
Period H
578%
>99.9%
< 0.0%
99.9%
97.3%
77.5%
7O9%
1 Assumes COD/TOC Ratio of 2 5.
2 Based on Ammonia or Nitrate Concentration
hourly averages determined to be
erroneous divided by thetotal numberof
hourly averages recorded.
Reclamation Facility
O&M Costs
The O&M costs for the reclamation
facility, including labor and material,
were $311,400 per year. Water produc-
tion costs were $0.60 per 1,000 gallons.
The distribution of costs may be
summarized as follows:
Labor Materials Total
Operations 49.4% 25.5% 74.9%
Maintenance 22.5% 2.6% 25.1%
Total 71.9% 28.1% 100.0%
Availability of Facility
and Process
Reclamation facility and process
availability (percent of time the facility
and process operate on demand) was
monitored during the test period. The
objective of operating the facility
continuously for the 8-month (5832
hour) test period was met except for 65
hours when influent was unavailable o
when facility equipment failed. Equip
ment failures experienced during the 8
month test period resulted in ai
estimated 20 days per year when thi
facility was not able to deliver reclaimei
water.
There were three dominant problems
1. Calcium carbonate encrustation
on equipment caused pump mal
functions and scale buildup on th
inside walls of piping; this reduce
flow capacity.
2. Plumbing failures within th
ozonator.
3. Carbon furnace equipment compc
nent failures.
Limitations
The true measure of performance b
developmental systems, such as th
WMS, and by the reclamation facility i
the contribution made toward identify
ing those key improvements necessai
for developing effective operation;
systems. This means identifying prok
lem areas and testing possible solutior
before designs are committed for open
tional systems. Predictions on pe
formance of some future operation,
system in terms of availability, reliabilit
and O&M costs based on existin
preprototypes are approximate an
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subject to error. Thus, the data devel-
oped in this test and presented in the
project report should be recognized as
such; i.e., measured performance of
commercial sensors as well as of
preptototype systems (biological analy-
zers, gas chromatograph analyzer, and
computer software).
The full report was submitted in ful-
fillment of IGA No. AD-80-F-0-054-0 by
the NASA Ames Research Center,
Moffett Field, CA, under the cosponsor-
ship of the U.S. Environmental Protec-
tion Agency
E. L Jeffers, R. L Brooks, D. Nibley, J. D. Poel. J. Perreira. andR. H. Nuss are with
the Boeing Company, Houston, TX 77058; K. Nishioka is with NASA Ames
Research Center, Moffett Field, CA 94035; and W. J. Sanchez, Jr.. and D. F.
Kriege are with the Santa Clara Valley Water District, San Jose. CA 95118.
John N. English is the EPA Project Officer (see below).
The complete report, entitled "Water Reclamation and A utomated Water Quality
Monitoring," (Order No. PB 82-227 497; Cost: $18.00, subject to change) will
be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Municipal Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
5
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