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

                                                             &U. S. GOVERNMENT PRINTING OFFICE: 198^559-09^0456

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