Field evaluation of resistivity sensors for in situ moisture measurement in a bioreactor landfill

    Authors

    D. Kumar; S. Jonnalagadda; P. Jain; N. A. Gawande; T. G. Townsend;D. R. Reinhart

    Abbreviated Journal Title

    Waste Manage.

    Keywords

    MEASURING WATER; WASTE; Engineering, Environmental; Environmental Sciences

    Abstract

    The ability of resistance-based sensors to measure in situ waste moisture content in a landfill was examined. One hundred and thirty-five resistance-based sensors were installed in a leachate recirculation well field at a bioreactor landfill in Florida, US. The performance of these sensors was studied for a period of over 6 years. The sensors were found to respond to an increase in moisture resulting from leachate recirculation. It was observed that 78% of sensors worked successfully in the field during the study period. The initial spatial average moisture content determined by the sensor readings (using a laboratory-derived calibration) was 42.8% compared to 23% from gravirnetric readings. Eighteen sensors (13%) showed that they were saturated before liquid addition, and no change in moisture content was observed in these sensors during the study period. Laboratory-derived calibration methods resulted in an over-estimation of moisture content. An alternate field-calibration method, where wetted sensor output was assumed equal to the average of gravimetric measurements for wet samples, was evaluated. The final spatial average Moisture contents were 64.2% and 44.4% for the laboratory-derived and field-derived calibration methodologies, respectively, compared to 45% measured gravimetrically from excavated waste samples. When moisture content was determined using a mass balance approach, the result was 34.6%. The results suggest that when appropriately calibrated, resistivity-based sensors can be used to obtain a reasonably accurate estimate of local moisture content. However, caution should be taken to extend the moisture content values that are representative of waste surrounding the sensors to estimate the overall moisture content on the landfill-wide scale. (c) 2008 Elsevier Ltd. All rights reserved.

    Journal Title

    Waste Management

    Volume

    29

    Issue/Number

    5

    Publication Date

    1-1-2009

    Document Type

    Article

    Language

    English

    First Page

    1547

    Last Page

    1557

    WOS Identifier

    WOS:000264977200014

    ISSN

    0956-053X

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