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 ------- 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: ------- 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. ------- 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 ------- 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. 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