Deborah Estrin

Jose Saez

Juyoul Kim

Miodrag Potkonjak

T. Bendikov

T. Schoellhammer

Thomas C. Harmon

Yeonjeong Park

eScholarship - University of California

UCLAPostersTitleNetworked Sensing of Nitrate in Support of Groundwater Quality ProtectionPermalinkhttps://escholarship.org/uc/item/82s9t9pzAuthorsJose SaezT. BendikovT. Schoellhammeret al.Publication Date2003eScholarship.org Powered by the California Digital LibraryUniversity of CaliforniaJose Saez1, T. Bendikov2, T. Schoellhammer3, Yeonjeong Park2, Juyoul Kim2, Miodrag Potkonjak3, Deborah Estrin3 and Thomas C. Harmon41Loyola Marymount University Civil & Environmental Engineering, 2UCLA Civil & Environmental Engineering, 3UCLA Computer Science, 4UC Merced School of EngineeringMunicipal wastewater flows in a megapolis like Los Angeles exceed 100s of millions of gallons per day.  In land-locked areas, prudent watershed management demands that we monitor and control the release of treated wastewater, and the associated contaminants and nutrients, into the environment.  If the release is into the soil, such as for irrigation or artificial recharge of aquifers, monitoring networks are currently sparse due to costs of deployment (well drilling and construction).  The objective of this  project is to systematically develop all aspects of a chemical sensor network, from sensor development to systems design.  The work is being completed in the context of a real-world problem of monitoring nitrate propagation in soil being irrigated with reclaimed wastewater.  • We are designing novel multi-level sensing stations (pylons) for temperature, moisture and nitrate, and deploy these nodes at varying spatial densities over a portion of a 30 acre test plot in Palmdale, CA.Response of the microsensor to different nitrate concentrations and temperatures (right).Palmdale, CA wastewater treatment plantReclaimed wastewaterirrigation pivot plots● Pylons are equipped with multiple sensor groups, each containing temperature, moisture and nitrate senors● Sensor groups are deployed along the trunk of the pylon for sensing at multiple soil depths● Multiple runners/tentacles protrude from the pylon at the surface for supplemental near-surface sensing● Each pylon monitors conditions (temperature, moisture and nitrate distributions) in its own region● Pylons communicate with other nearby pylons to delineate nitrate concentration distribution in time and spacePrototype Pylon Design● The watering pivot is instrumented with high accuracy nitrate and flow sensors● The pivot communicates with nearby pylons to inform them of current water conditions● Feedback from the pylons can be used to help control pivot operation, maximizing the safe discharge of nitrate-laden wastewater.PivotNSFThe Center for Embedded Networked Sensing (CENS)is a National Science Foundation Science & Technology Centerunder Cooperative Agreement #CCR-01207781. Sensor developmentA potentiometric ion selective electrode (ISE) approach by Hutchins and Bachas Anal. Chem. 67, 1654(1995) is being investigated.The ion selective membrane used is polypyrrole doped with nitrate anions.This approach is relatively simple and expected to scale down to the microchip.- Presently attempting silicon-based prototypes- Current recipe not long-lived 1 2 3 4 5160200240280320360a)                            For linear portion of the graph    20 oC       Slope: 52.2 mV, R2 = 0.999    30 oC       Slope: 55.3 mV, R2 = 0.999    40 oC       Slope: 55.9 mV, R2 = 0.999    50 oC       Slope: 58.2 mV, R2 = 0.999    60 oC       Slope: 57.6 mV, R2 = 0.999    70 oC       Slope: 57.5 mV, R2 = 0.999Solution: Pyrrole 1M, NaNO3 0.1MDeposition: Constant current 100 µA during 20 minConditioning: 24 hours in NaNO3 10-2 MMeasurements: 2 days after depositionISA: (NH4)2SO4 1 x 10-2 M-log(NO3-)  Voltage, mV1 2 3 4 5 64080120160200240280320360Commercial and Homemade electrodes    Thermoorion 1, Slope: 53.4 mV    Thermorion 2, Slope: 54.2 mV    Sentek 1, Slope: 53.6 mV    Sentek 2, Slope: 53.2 mV    Carbon Fiber, Slope: 58.2 mV    Pencil Lead, Slope: 55.9 mV-log(NO3-)  Voltage (mV)Comparison of lab-fabricated microsensor response to COTS sensors2. Calibration and testingSensor-level calibration is being undertaken under a range of environmental conditions (pH, temperature, salinity, etc.)Sensor network calibration will focus on minimizing the error transmitted from an array of sensors.moisture sensorsnitrate sensorstemperaturesensorwirelessmote raincollectorNetworked Sensing of Nitrate in Support of Groundwater Quality ProtectionCenter for Embedded Networked SensingIntroduction: Soil sensor networks in a real-world applicationProblem Description: Creating sensors that scale to error resilient, large-scale deploymentProposed Solution: Irrigation using reclaimed wastewater—protecting the groundwaterUCLA – UCR – Caltech – USC – CSU – JPL – UC Merced

English

Networked Sensing of Nitrate in Support of Groundwater Quality Protection

Networked Sensing of Nitrate in Support of Groundwater Quality Protection

Abstract

Similar works

Full text

Available Versions

eScholarship - University of California